Extended Quantum Field Theory, Index Theory, and the Parity Anomaly
NASA Astrophysics Data System (ADS)
Müller, Lukas; Szabo, Richard J.
2018-06-01
We use techniques from functorial quantum field theory to provide a geometric description of the parity anomaly in fermionic systems coupled to background gauge and gravitational fields on odd-dimensional spacetimes. We give an explicit construction of a geometric cobordism bicategory which incorporates general background fields in a stack, and together with the theory of symmetric monoidal bicategories we use it to provide the concrete forms of invertible extended quantum field theories which capture anomalies in both the path integral and Hamiltonian frameworks. Specialising this situation by using the extension of the Atiyah-Patodi-Singer index theorem to manifolds with corners due to Loya and Melrose, we obtain a new Hamiltonian perspective on the parity anomaly. We compute explicitly the 2-cocycle of the projective representation of the gauge symmetry on the quantum state space, which is defined in a parity-symmetric way by suitably augmenting the standard chiral fermionic Fock spaces with Lagrangian subspaces of zero modes of the Dirac Hamiltonian that naturally appear in the index theorem. We describe the significance of our constructions for the bulk-boundary correspondence in a large class of time-reversal invariant gauge-gravity symmetry-protected topological phases of quantum matter with gapless charged boundary fermions, including the standard topological insulator in 3 + 1 dimensions.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ortiz, Gerardo, E-mail: ortizg@indiana.edu; Cobanera, Emilio
We investigate Majorana modes of number-conserving fermionic superfluids from both basic physics principles, and concrete models perspectives. After reviewing a criterion for establishing topological superfluidity in interacting systems, based on many-body fermionic parity switches, we reveal the emergence of zero-energy modes anticommuting with fermionic parity. Those many-body Majorana modes are constructed as coherent superpositions of states with different number of fermions. While realization of Majorana modes beyond mean field is plausible, we show that the challenge to quantum-control them is compounded by particle-conservation, and more realistic protocols will have to balance engineering needs with astringent constraints coming from superselection rules.more » Majorana modes in number-conserving systems are the result of a peculiar interplay between quantum statistics, fermionic parity, and an unusual form of spontaneous symmetry breaking. We test these ideas on the Richardson–Gaudin–Kitaev chain, a number-conserving model solvable by way of the algebraic Bethe ansatz, and equivalent in mean field to a long-range Kitaev chain.« less
Flavor and topological current correlators in parity-invariant three-dimensional QED
NASA Astrophysics Data System (ADS)
Karthik, Nikhil; Narayanan, Rajamani
2017-09-01
We use lattice regularization to study the flow of the flavor-triplet fermion current central charge CJf from its free field value in the ultraviolet limit to its conformal value in the infrared limit of the parity-invariant three-dimensional QED with two flavors of two-component fermions. The dependence of CJf on the scale is weak with a tendency to be below the free field value at intermediate distances. Our numerical data suggest that the flavor-triplet fermion current and the topological current correlators become degenerate within numerical errors in the infrared limit, thereby supporting an enhanced O(4) symmetry predicted by strong self-duality. Further, we demonstrate that fermion dynamics is necessary for the scale-invariant behavior of parity-invariant three-dimensional QED by showing that the pure gauge theory with noncompact gauge action has a nonzero bilinear condensate.
Controlled parity switch of persistent currents in quantum ladders
NASA Astrophysics Data System (ADS)
Filippone, Michele; Bardyn, Charles-Edouard; Giamarchi, Thierry
2018-05-01
We investigate the behavior of persistent currents for a fixed number of noninteracting fermions in a periodic quantum ladder threaded by Aharonov-Bohm and transverse magnetic fluxes Φ and χ . We show that the coupling between ladder legs provides a way to effectively change the ground-state fermion-number parity, by varying χ . Specifically, we demonstrate that varying χ by 2 π (one flux quantum) leads to an apparent fermion-number parity switch. We find that persistent currents exhibit a robust 4 π periodicity as a function of χ , despite the fact that χ →χ +2 π leads to modifications of order 1 /N of the energy spectrum, where N is the number of sites in each ladder leg. We show that these parity-switch and 4 π periodicity effects are robust with respect to temperature and disorder, and outline potential physical realizations using cold atomic gases and photonic lattices, for bosonic analogs of the effects.
Quantum computing with Majorana fermion codes
NASA Astrophysics Data System (ADS)
Litinski, Daniel; von Oppen, Felix
2018-05-01
We establish a unified framework for Majorana-based fault-tolerant quantum computation with Majorana surface codes and Majorana color codes. All logical Clifford gates are implemented with zero-time overhead. This is done by introducing a protocol for Pauli product measurements with tetrons and hexons which only requires local 4-Majorana parity measurements. An analogous protocol is used in the fault-tolerant setting, where tetrons and hexons are replaced by Majorana surface code patches, and parity measurements are replaced by lattice surgery, still only requiring local few-Majorana parity measurements. To this end, we discuss twist defects in Majorana fermion surface codes and adapt the technique of twist-based lattice surgery to fermionic codes. Moreover, we propose a family of codes that we refer to as Majorana color codes, which are obtained by concatenating Majorana surface codes with small Majorana fermion codes. Majorana surface and color codes can be used to decrease the space overhead and stabilizer weight compared to their bosonic counterparts.
NASA Astrophysics Data System (ADS)
Hays, M.; de Lange, G.; Serniak, K.; van Woerkom, D. J.; Väyrynen, J. I.; van Heck, B.; Vool, U.; Krogstrup, P.; Nygård, J.; Frunzio, L.; Geresdi, A.; Glazman, L. I.; Devoret, M. H.
Proximitized semiconducting nanowires subject to magnetic field should display topological superconductivity and support Majorana zero modes which have non-Abelian braiding statistics. The conventional Andreev levels formed in such wires in the absence of field are a precursor to these exotic zero modes. The fermion-parity switching time of Andreev levels sets a lower bound on the bandwidth required for experiments aimed at harnessing non-Abelian braiding statistics. We demonstrate the observation of quantum jumps between even and odd-parity states of an individual Andreev bound state in a non-topological junction, providing a direct measurement of the state populations and the parity lifetime. Work supported by: ARO, ONR, AFOSR, EU Marie Curie and YINQE.
Dai, Li; Kuo, Watson; Chung, Ming-Chiang
2015-01-01
We propose a scheme for extracting entangled charge qubits from quantum-dot chains that support zero-energy edge modes. The edge mode is composed of Majorana fermions localized at the ends of each chain. The qubit, logically encoded in double quantum dots, can be manipulated through tunneling and pairing interactions between them. The detailed form of the entangled state depends on both the parity measurement (an even or odd number) of the boundary-site electrons in each chain and the teleportation between the chains. The parity measurement is realized through the dispersive coupling of coherent-state microwave photons to the boundary sites, while the teleportation is performed via Bell measurements. Our scheme illustrates localizable entanglement in a fermionic system, which serves feasibly as a quantum repeater under realistic experimental conditions, as it allows for finite temperature effect and is robust against disorders, decoherence and quasi-particle poisoning. PMID:26062033
Negative parity states and some electromagnetic transition properties of even-odd erbium isotopes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yazar, Harun Resit; Uluer, Ihsan
2007-03-15
The negative parity states and some electromagnetic transition properties of even-odd erbium isotopes ({sup 159,161,163,165}Er) were studied within the framework of the interacting boson-fermion model. The single fermion is assumed to be in one of the lh{sub 9/2},3p{sub 3/2},2f{sub 5/2}, and 3p{sub 1/2} single-particle orbits. It was found that the calculated negative parity state energy spectra of the even-odd erbium isotopes agree quite well with the experimental data. The B(E2) values were also calculated and compared with the experimental data.
Non-Abelian fermion parity interferometry of Majorana bound states in a Fermi sea
NASA Astrophysics Data System (ADS)
Dahan, Daniel; Tanhayi Ahari, Mostafa; Ortiz, Gerardo; Seradjeh, Babak; Grosfeld, Eytan
We study the quantum dynamics of Majorana and regular fermion bound states coupled to a one-dimensional lead. The dynamics following the quench in the coupling to the lead exhibits a series of dynamical revivals as the bound state propagates in the lead and reflects from the boundaries. We show that the nature of revivals for a single Majorana bound state depends uniquely on the presence of a resonant level in the lead. When two spatially separated Majorana modes are coupled to the lead, the revivals depend only on the phase difference between their host superconductors. Remarkably, the quench in this case effectively performs a fermion-parity interferometry between Majorana bound states, revealing their unique non-Abelian braiding. Using both analytical and numerical techniques, we find the pattern of fermion parity transfers following the quench, study its evolution in the presence of disorder and interactions, and thus, ascertain the fate of Majorana in a rough Fermi sea. Work supported in part by BSF Grant No. 2014345, ISF Grant Nos. 401/12 and 1626/16, EU Seventh Framework Programme (FP7/2007-2013) Grant No. 303742, NSF CAREER Grant DMR-1350663 and the College of Arts and Sciences at Indiana University.
Extending matchgates into universal quantum computation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brod, Daniel J.; Galvao, Ernesto F.
2011-08-15
Matchgates are a family of two-qubit gates associated with noninteracting fermions. They are classically simulatable if acting only on nearest neighbors but become universal for quantum computation if we relax this restriction or use swap gates [Jozsa and Miyake, Proc. R. Soc. A 464, 3089 (2008)]. We generalize this result by proving that any nonmatchgate parity-preserving unitary is capable of extending the computational power of matchgates into universal quantum computation. We identify the single local invariant of parity-preserving unitaries responsible for this, and discuss related results in the context of fermionic systems.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lee, Hye-Sung; Soni, Amarjit
2013-01-01
We present a very simple 4th-generation (4G) model with an Abelian gauge interaction under which only the 4G fermions have nonzero charge. The U(1) gauge symmetry can have a Z_2 residual discrete symmetry (4G-parity), which can stabilize the lightest 4G particle (L4P). When the 4G neutrino is the L4P, it would be a neutral and stable particle and the other 4G fermions would decay into the L4P leaving the trace of missing energy plus the standard model fermions. Because of the new symmetry, the 4G particle creation and decay modes are different from those of the sequential 4G model, andmore » the 4G particles can be appreciably lighter than typical experimental bounds.« less
Extending matchgates into universal quantum computation
NASA Astrophysics Data System (ADS)
Brod, Daniel J.; Galvão, Ernesto F.
2011-08-01
Matchgates are a family of two-qubit gates associated with noninteracting fermions. They are classically simulatable if acting only on nearest neighbors but become universal for quantum computation if we relax this restriction or use swap gates [Jozsa and Miyake, Proc. R. Soc. ANATUAS1364-502110.1098/rspa.2008.0189 464, 3089 (2008)]. We generalize this result by proving that any nonmatchgate parity-preserving unitary is capable of extending the computational power of matchgates into universal quantum computation. We identify the single local invariant of parity-preserving unitaries responsible for this, and discuss related results in the context of fermionic systems.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Delgado-Acosta, E. G.; Napsuciale, Mauro; Rodriguez, Simon
We develop a second order formalism for massive spin 1/2 fermions based on the projection over Poincare invariant subspaces in the ((1/2),0)+(0,(1/2)) representation of the homogeneous Lorentz group. Using the U(1){sub em} gauge principle we obtain a second order description for the electromagnetic interactions of a spin 1/2 fermion with two free parameters, the gyromagnetic factor g and a parameter {xi} related to odd-parity Lorentz structures. We calculate Compton scattering in this formalism. In the particular case g=2, {xi}=0, and for states with well-defined parity, we recover Dirac results. In general, we find the correct classical limit and a finitemore » value r{sub c}{sup 2} for the forward differential cross section, independent of the photon energy and of the value of the parameters g and {xi}. The differential cross section vanishes at high energies for all g, {xi} except in the forward direction. The total cross section at high energies vanishes only for g=2, {xi}=0. We argue that this formalism is more convenient than Dirac theory in the description of low energy electromagnetic properties of baryons and illustrate the point with the proton case.« less
Quantum return probability of a system of N non-interacting lattice fermions
NASA Astrophysics Data System (ADS)
Krapivsky, P. L.; Luck, J. M.; Mallick, K.
2018-02-01
We consider N non-interacting fermions performing continuous-time quantum walks on a one-dimensional lattice. The system is launched from a most compact configuration where the fermions occupy neighboring sites. We calculate exactly the quantum return probability (sometimes referred to as the Loschmidt echo) of observing the very same compact state at a later time t. Remarkably, this probability depends on the parity of the fermion number—it decays as a power of time for even N, while for odd N it exhibits periodic oscillations modulated by a decaying power law. The exponent also slightly depends on the parity of N, and is roughly twice smaller than what it would be in the continuum limit. We also consider the same problem, and obtain similar results, in the presence of an impenetrable wall at the origin constraining the particles to remain on the positive half-line. We derive closed-form expressions for the amplitudes of the power-law decay of the return probability in all cases. The key point in the derivation is the use of Mehta integrals, which are limiting cases of the Selberg integral.
NASA Astrophysics Data System (ADS)
Duret, Q.; Machet, B.
2010-10-01
Starting from Wigner's symmetry representation theorem, we give a general account of discrete symmetries (parity P, charge conjugation C, time-reversal T), focusing on fermions in Quantum Field Theory. We provide the rules of transformation of Weyl spinors, both at the classical level (grassmanian wave functions) and quantum level (operators). Making use of Wightman's definition of invariance, we outline ambiguities linked to the notion of classical fermionic Lagrangian. We then present the general constraints cast by these transformations and their products on the propagator of the simplest among coupled fermionic system, the one made with one fermion and its antifermion. Last, we put in correspondence the propagation of C eigenstates (Majorana fermions) and the criteria cast on their propagator by C and CP invariance.
NASA Astrophysics Data System (ADS)
Rojas, Eduardo; Erler, Jens
2015-10-01
We classify the quantum numbers of the extra U(1)' symmetries contained in E 6. In particular, we categorize the cases with rational charges and present the full list of models which arise from the chains of the maximal subgroups of E 6. As an application, the classification allows us to determine all embeddings of the Standard Model fermions in all possible decompositions of the fundamental representation of E 6 under its maximal subgroups. From this we find alternative chains of subgroups for Grand Unified Theories. We show how many of the known models including some new ones appear in alternative breaking patterns. We also use low energy constraints coming from parity-violating asymmetry measurements and atomic parity non-conservation to set limits on the E 6 motivated parameter space for a Z ' boson mass of 1.2 TeV. We include projected limits for the present and upcoming QWEAK, MOLLER and SOLID experiments.
Critical flavor number of the Thirring model in three dimensions
NASA Astrophysics Data System (ADS)
Wellegehausen, Björn H.; Schmidt, Daniel; Wipf, Andreas
2017-11-01
The Thirring model is a four-fermion theory with a current-current interaction and U (2 N ) chiral symmetry. It is closely related to three-dimensional QED and other models used to describe properties of graphene. In addition, it serves as a toy model to study chiral symmetry breaking. In the limit of flavor number N →1 /2 it is equivalent to the Gross-Neveu model, which shows a parity-breaking discrete phase transition. The model was already studied with different methods, including Dyson-Schwinger equations, functional renormalization group methods, and lattice simulations. Most studies agree that there is a phase transition from a symmetric phase to a spontaneously broken phase for a small number of fermion flavors, but no symmetry breaking for large N . But there is no consensus on the critical flavor number Ncr above which there is no phase transition anymore and on further details of the critical behavior. Values of N found in the literature vary between 2 and 7. All earlier lattice studies were performed with staggered fermions. Thus it is questionable if in the continuum limit the lattice model recovers the internal symmetries of the continuum model. We present new results from lattice Monte Carlo simulations of the Thirring model with SLAC fermions which exactly implement all internal symmetries of the continuum model even at finite lattice spacing. If we reformulate the model in an irreducible representation of the Clifford algebra, we find, in contradiction to earlier results, that the behavior for even and odd flavor numbers is very different: for even flavor numbers, chiral and parity symmetry are always unbroken; for odd flavor numbers, parity symmetry is spontaneously broken below the critical flavor number Nircr=9 , while chiral symmetry is still unbroken.
Positive parity states and some electromagnetic transition properties of even-odd europium isotopes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yazar, Harun Resit, E-mail: yazar@nevsehir.edu.tr
2013-06-15
The positive-parity low-spin states of even-odd Europium isotopes ({sup 151-155}Eu) were studied within the framework of the interacting boson-fermion model. The calculated positive low-spin state energy spectra of the odd Eu isotope were found to agree quite well with the experimental data. The B(E2) values were also calculated and it was found that the calculated positive-parity low-spin state energy spectra of the odd-A Eu isotopes agree quite well with the experimental data.
Exact ground states and topological order in interacting Kitaev/Majorana chains
NASA Astrophysics Data System (ADS)
Katsura, Hosho; Schuricht, Dirk; Takahashi, Masahiro
2015-09-01
We study a system of interacting spinless fermions in one dimension that, in the absence of interactions, reduces to the Kitaev chain [Kitaev, Phys. Usp. 44, 131 (2001), 10.1070/1063-7869/44/10S/S29]. In the noninteracting case, a signal of topological order appears as zero-energy modes localized near the edges. We show that the exact ground states can be obtained analytically even in the presence of nearest-neighbor repulsive interactions when the on-site (chemical) potential is tuned to a particular function of the other parameters. As with the noninteracting case, the obtained ground states are twofold degenerate and differ in fermionic parity. We prove the uniqueness of the obtained ground states and show that they can be continuously deformed to the ground states of the noninteracting Kitaev chain without gap closing. We also demonstrate explicitly that there exists a set of operators each of which maps one of the ground states to the other with opposite fermionic parity. These operators can be thought of as an interacting generalization of Majorana edge zero modes.
Effective theory of flavor for Minimal Mirror Twin Higgs
NASA Astrophysics Data System (ADS)
Barbieri, Riccardo; Hall, Lawrence J.; Harigaya, Keisuke
2017-10-01
We consider two copies of the Standard Model, interchanged by an exact parity symmetry, P. The observed fermion mass hierarchy is described by suppression factors ɛ^{n_i} for charged fermion i, as can arise in Froggatt-Nielsen and extra-dimensional theories of flavor. The corresponding flavor factors in the mirror sector are ɛ^' {n}_i} , so that spontaneous breaking of the parity P arises from a single parameter ɛ'/ɛ, yielding a tightly constrained version of Minimal Mirror Twin Higgs, introduced in our previous paper. Models are studied for simple values of n i , including in particular one with SU(5)-compatibility, that describe the observed fermion mass hierarchy. The entire mirror quark and charged lepton spectrum is broadly predicted in terms of ɛ'/ɛ, as are the mirror QCD scale and the decoupling temperature between the two sectors. Helium-, hydrogen- and neutron-like mirror dark matter candidates are constrained by self-scattering and relic ionization. In each case, the allowed parameter space can be fully probed by proposed direct detection experiments. Correlated predictions are made as well for the Higgs signal strength and the amount of dark radiation.
Matter antimatter domains: A possible solution to the CP domain wall problem in the early universe
NASA Technical Reports Server (NTRS)
Mohanty, A. K.; Stecker, F. W.
1984-01-01
An SU(5) grand unified theory model is used to show how the degeneracy between vacua with different spontaneously broken charge parity can be dynamically lifted by a condensate of heavy fermion pairs. This drives a phase transition to a unique vacuum state with definite charge parity. The transition eliminates the domain walls in a matter antimatter symmetric domain cosmology.
Effective theory of flavor for Minimal Mirror Twin Higgs
Barbieri, Riccardo; Hall, Lawrence J.; Harigaya, Keisuke
2017-10-03
We consider two copies of the Standard Model, interchanged by an exact parity symmetry, P. The observed fermion mass hierarchy is described by suppression factors ϵ more » $$n_i$$ for charged fermion i, as can arise in Froggatt-Nielsen and extra-dimensional theories of flavor. The corresponding flavor factors in the mirror sector are ϵ' $$n_i$$, so that spontaneous breaking of the parity P arises from a single parameter ϵ'/ϵ, yielding a tightly constrained version of Minimal Mirror Twin Higgs, introduced in our previous paper. Models are studied for simple values of n i, including in particular one with SU(5)-compatibility, that describe the observed fermion mass hierarchy. The entire mirror quark and charged lepton spectrum is broadly predicted in terms of ϵ'/ϵ, as are the mirror QCD scale and the decoupling temperature between the two sectors. Helium-, hydrogen- and neutron-like mirror dark matter candidates are constrained by self-scattering and relic ionization. Lastly, in each case, the allowed parameter space can be fully probed by proposed direct detection experiments. Correlated predictions are made as well for the Higgs signal strength and the amount of dark radiation.« less
Grand unification and low scale implications: D2 parity for unification and neutrino masses
NASA Astrophysics Data System (ADS)
Tavartkiladze, Zurab
2014-06-01
The Grand Unified SU(5)-SU(5)' model, augmented with D2 Parity, is considered. The latter play crucial role for phenomenology. The model has several novel properties and gives interesting phenomenological implications. The charged leptons together with right handed (or sterile) neutrinos emerge es composite states. Within considered scenario, we study the charged fermion and neutrino mass generation. Moreover, we show that the model gives successful gauge coupling unification.
Majorana fermion surface code for universal quantum computation
Vijay, Sagar; Hsieh, Timothy H.; Fu, Liang
2015-12-10
In this study, we introduce an exactly solvable model of interacting Majorana fermions realizing Z 2 topological order with a Z 2 fermion parity grading and lattice symmetries permuting the three fundamental anyon types. We propose a concrete physical realization by utilizing quantum phase slips in an array of Josephson-coupled mesoscopic topological superconductors, which can be implemented in a wide range of solid-state systems, including topological insulators, nanowires, or two-dimensional electron gases, proximitized by s-wave superconductors. Our model finds a natural application as a Majorana fermion surface code for universal quantum computation, with a single-step stabilizer measurement requiring no physicalmore » ancilla qubits, increased error tolerance, and simpler logical gates than a surface code with bosonic physical qubits. We thoroughly discuss protocols for stabilizer measurements, encoding and manipulating logical qubits, and gate implementations.« less
Positive parity low spin states of odd-mass tellurium isotopes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yazar, Harun Resit
2006-11-15
In this work, we analyse the positive parity of states of odd-mass nucleus within the framework of interacting boson fermion model. The result of an IBFM-1 multilevel calculation with the lg{sub 9/2}, 2d{sub 5/2}, 2d{sub 3/2}, 3s{sub 1/2} and one level, 1h{sub 11/2} with negative parity, single particle orbits is reported for the positive parity states of the odd mass nucleus {sup 123-125}Te. Also, an IBM-1 calculation is presented for the low-lying states in the even-even {sup 124-126}Te core nucleus. The energy levels and B (E2) transition probabilities were calculated and compared with the experimental data. It was found thatmore » the calculated positive parity low spin state energy spectra of the odd-mass {sup 123-125}Te isotopes agree quite well with the experimental data.« less
Chirality and gravitational parity violation.
Bargueño, Pedro
2015-06-01
In this review, parity-violating gravitational potentials are presented as possible sources of both true and false chirality. In particular, whereas phenomenological long-range spin-dependent gravitational potentials contain both truly and falsely chiral terms, it is shown that there are models that extend general relativity including also coupling of fermionic degrees of freedom to gravity in the presence of torsion, which give place to short-range truly chiral interactions similar to that usually considered in molecular physics. Physical mechanisms which give place to gravitational parity violation together with the expected size of the effects and their experimental constraints are discussed. Finally, the possible role of parity-violating gravity in the origin of homochirality and a road map for future research works in quantum chemistry is presented. © 2015 Wiley Periodicals, Inc.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Constantinou, Martha; Panagopoulos, Haralambos; Skouroupathis, Apostolos
2011-04-01
In this work we calculate the corrections to the amputated Green's functions of four-fermion operators, in 1-loop lattice perturbation theory. One of the novel aspects of our calculations is that they are carried out to second order in the lattice spacing, O(a{sup 2}). We employ the Wilson/clover action for massless fermions (also applicable for the twisted mass action in the chiral limit) and a family of Symanzik improved actions for gluons. Our calculations have been carried out in a general covariant gauge. Results have been obtained for several popular choices of values for the Symanzik coefficients (Plaquette, Tree-level Symanzik, Iwasaki,more » TILW and DBW2 action). While our Green's function calculations regard any pointlike four-fermion operators which do not mix with lower dimension ones, we pay particular attention to {Delta}F=2 operators, both parity conserving and parity violating (F stands for flavor: S, C, B). By appropriately projecting those bare Green's functions we compute the perturbative renormalization constants for a complete basis of four-fermion operators and we study their mixing pattern. For some of the actions considered here, even O(a{sup 0}) results did not exist in the literature to date. The correction terms which we calculate (along with our previous O(a{sup 2}) calculation of Z{sub {Psi}}[M. Constantinou, V. Lubicz, H. Panagopoulos, and F. Stylianou, J. High Energy Phys. 10 (2009) 064.][M. Constantinou, P. Dimopoulos, R. Frezzotti, G. Herdoiza, K. Jansen, V. Lubicz, H. Panagopoulos, G. C. Rossi, S. Simula, F. Stylianou, and A. Vladikas, J. High Energy Phys. 08 (2010) 068.][C. Alexandrou, M. Constantinou, T. Korzec, H. Panagopoulos, and F. Stylianou (unpublished).]) are essential ingredients for minimizing the lattice artifacts which are present in nonperturbative evaluations of renormalization constants with the RI{sup '}-MOM method. Our perturbative results, for the matrix elements of {Delta}F=2 operators and for the corresponding renormalization matrices, depend on a large number of parameters: coupling constant, number of colors, lattice spacing, external momentum, clover parameter, Symanzik coefficients, gauge parameter. To make these results most easily accessible to the reader, we have included them in the distribution package of this paper, as an ASCII file named: 4-fermi.m; the file is best perused as Mathematica input. The main results of this work have been applied to improve nonperturbative estimates of the B{sub K}-parameter in N{sub F}=2 twisted mass lattice QCD [M. Constantinou, P. Dimopoulos, R. Frezzotti, K. Jansen, V. Gimenez, V. Lubicz, F. Mescia, H. Panagopoulos, M. Papinutto, G. C. Rossi, S. Simula, A. Skouroupathis, F. Stylianou, and A. Vladikas, arXiv:1009.5606.].« less
Constraints on T-Odd, P-Even Interactions from Electric Dipole Moments
DOE Office of Scientific and Technical Information (OSTI.GOV)
A. Kurylov; G. C. McLaughlin; M.J. Ramsey-Musolf
2001-03-01
We construct the relationship between nonrenormalizable,effective, time-reversal violating (TV) parity-conserving (PC) interactions of quarks and gauge bosons and various low-energy TVPC and TV parity-violating (PV) observables. Using effective field theory methods, we delineate the scenarios under which experimental limits on permanent electric dipole moments (EDM's) of the electron, neutron, and neutral atoms as well as limits on TVPC observables provide the most stringent bounds on new TVPC interactions. Under scenarios in which parity invariance is restored at short distances, the one-loop EDM of elementary fermions generate the most severe constraints. The limits derived from the atomic EDM of {sup 199}Hgmore » are considerably weaker. When parity symmetry remains broken at short distances, direct TVPC search limits provide the least ambiguous bounds. The direct limits follow from TVPC interactions between two quarks.« less
Selected topics on dynamical symmetry breaking
DOE Office of Scientific and Technical Information (OSTI.GOV)
Veldhuis, W.T.A.
1993-12-31
In chapter 2 the fermion number induced by nontrivial topological configurations in the O(3) nonlinear {sigma} model in 2 + 1 dimensions is studied in the presence of a parity breaking fermion mass term. We consider a scalar background configuration that adiabatically evolves from the normal vacuum to a soliton of winding number unity. The appearance of zero energy modes is analyzed as a function of the relative magnitudes of the explicit, odd parity, fermion mass, m{sub odd}, the fermion mass induced by the Yukawa coupling, m{sub Y}, and the inverse soliton width, 1/{rho}{sub s}. We find {rho}{sub c}, themore » maximum value of {rho} = {rho}{sub s}m{sub Y} for which a fermion zero energy level crossing occurs during the adiabatical evolution. We obtain that whenever the ratio M{sub f} = m{sub odd}/m{sub Y} < 1 and {rho} > {rho}{sub c}(M{sub f}) the ground state charge of the soliton is wholly determined by its topological charge. Otherwise, it vanishes. In chapter 3 the top quark mass prediction in supersymmetric top condensate models is found to be insensitive to the inclusion of the effects of higher dimensional operators. For associated coefficients of characteristically moderate strength, the supersymmetric renormalization group trajectories are strongly focused to the infrared quasi-fixed point of the top Yukawa coupling constant. In chapter 4 the sensitivity of the top quark and Higgs boson masses in the top condensate model to two loop radiative corrections is studied. Both the top quark and the Higgs boson masses vary by a few GeV with respect to their values in the one loop calculation. Finally, in chapter 5 an upper bound on the mass of the lightest neutral scalar Higgs boson is calculated in an extended version of the minimal supersymmetric standard model that contains an additional Higgs singlet.« less
Abazov, Victor Mukhamedovich
2014-10-16
In this study, we present constraints on models containing non-standard model values for the spinmore » $J$ and parity $P$ of the Higgs boson, $H$, in up to 9.7~fb$$^{-1}$$ of $$p\\bar{p}$$ collisions at $$\\sqrt{s} = $$ 1.96~TeV collected with the D0 detector at the Fermilab Tevatron Collider. These are the first studies of Higgs boson $$J^{P}$$ with fermions in the final state. In the $$ZH\\rightarrow \\ell\\ell b\\bar{b}$$, $$WH\\rightarrow \\ell\
Discrete spacetime, quantum walks, and relativistic wave equations
NASA Astrophysics Data System (ADS)
Mlodinow, Leonard; Brun, Todd A.
2018-04-01
It has been observed that quantum walks on regular lattices can give rise to wave equations for relativistic particles in the continuum limit. In this paper, we define the three-dimensional discrete-time walk as a product of three coined one-dimensional walks. The factor corresponding to each one-dimensional walk involves two projection operators that act on an internal coin space; each projector is associated with either the "forward" or "backward" direction in that physical dimension. We show that the simple requirement that there is no preferred axis or direction along an axis—that is, that the walk be symmetric under parity transformations and steps along different axes of the cubic lattice be uncorrelated—leads, in the case of the simplest solution, to the requirement that the continuum limit of the walk is fully Lorentz-invariant. We show further that, in the case of a massive particle, this symmetry requirement necessitates the use of a four-dimensional internal space (as in the Dirac equation). The "coin flip" operation is generated by the parity transformation on the internal coin space, while the differences of the projection operators associated with each dimension must all anticommute. Finally, we discuss the leading correction to the continuum limit, and the possibility of distinguishing through experiment between the discrete random walk and the continuum-based Dirac equation as a description of fermion dynamics.
Three-dimensional Majorana fermions in chiral superconductors
Kozii, Vladyslav; Venderbos, Jorn W. F.; Fu, Liang
2016-12-07
Using a systematic symmetry and topology analysis, we establish that three-dimensional chiral superconductors with strong spin-orbit coupling and odd-parity pairing generically host low-energy nodal quasiparticles that are spin-nondegenerate and realize Majorana fermions in three dimensions. By examining all types of chiral Cooper pairs with total angular momentum J formed by Bloch electrons with angular momentum j in crystals, we obtain a comprehensive classification of gapless Majorana quasiparticles in terms of energy-momentum relation and location on the Fermi surface. We show that the existence of bulk Majorana fermions in the vicinity of spin-selective point nodes is rooted in the nonunitary naturemore » of chiral pairing in spin-orbit–coupled superconductors. We address experimental signatures of Majorana fermions and find that the nuclear magnetic resonance spin relaxation rate is significantly suppressed for nuclear spins polarized along the nodal direction as a consequence of the spin-selective Majorana nature of nodal quasiparticles. Furthermore, Majorana nodes in the bulk have nontrivial topology and imply the presence of Majorana bound states on the surface, which form arcs in momentum space. We conclude by proposing the heavy fermion superconductor PrOs 4Sb 12 and related materials as promising candidates for nonunitary chiral superconductors hosting three-dimensional Majorana fermions.« less
Three-dimensional Majorana fermions in chiral superconductors.
Kozii, Vladyslav; Venderbos, Jörn W F; Fu, Liang
2016-12-01
Using a systematic symmetry and topology analysis, we establish that three-dimensional chiral superconductors with strong spin-orbit coupling and odd-parity pairing generically host low-energy nodal quasiparticles that are spin-nondegenerate and realize Majorana fermions in three dimensions. By examining all types of chiral Cooper pairs with total angular momentum J formed by Bloch electrons with angular momentum j in crystals, we obtain a comprehensive classification of gapless Majorana quasiparticles in terms of energy-momentum relation and location on the Fermi surface. We show that the existence of bulk Majorana fermions in the vicinity of spin-selective point nodes is rooted in the nonunitary nature of chiral pairing in spin-orbit-coupled superconductors. We address experimental signatures of Majorana fermions and find that the nuclear magnetic resonance spin relaxation rate is significantly suppressed for nuclear spins polarized along the nodal direction as a consequence of the spin-selective Majorana nature of nodal quasiparticles. Furthermore, Majorana nodes in the bulk have nontrivial topology and imply the presence of Majorana bound states on the surface, which form arcs in momentum space. We conclude by proposing the heavy fermion superconductor PrOs 4 Sb 12 and related materials as promising candidates for nonunitary chiral superconductors hosting three-dimensional Majorana fermions.
Three-dimensional Majorana fermions in chiral superconductors
Kozii, Vladyslav; Venderbos, Jörn W. F.; Fu, Liang
2016-01-01
Using a systematic symmetry and topology analysis, we establish that three-dimensional chiral superconductors with strong spin-orbit coupling and odd-parity pairing generically host low-energy nodal quasiparticles that are spin-nondegenerate and realize Majorana fermions in three dimensions. By examining all types of chiral Cooper pairs with total angular momentum J formed by Bloch electrons with angular momentum j in crystals, we obtain a comprehensive classification of gapless Majorana quasiparticles in terms of energy-momentum relation and location on the Fermi surface. We show that the existence of bulk Majorana fermions in the vicinity of spin-selective point nodes is rooted in the nonunitary nature of chiral pairing in spin-orbit–coupled superconductors. We address experimental signatures of Majorana fermions and find that the nuclear magnetic resonance spin relaxation rate is significantly suppressed for nuclear spins polarized along the nodal direction as a consequence of the spin-selective Majorana nature of nodal quasiparticles. Furthermore, Majorana nodes in the bulk have nontrivial topology and imply the presence of Majorana bound states on the surface, which form arcs in momentum space. We conclude by proposing the heavy fermion superconductor PrOs4Sb12 and related materials as promising candidates for nonunitary chiral superconductors hosting three-dimensional Majorana fermions. PMID:27957543
Global Symmetries of Naive and Staggered Fermions in Arbitrary Dimensions
NASA Astrophysics Data System (ADS)
Kieburg, Mario; Würfel, Tim R.
2018-03-01
It is well-known that staggered fermions do not necessarily satisfy the same global symmetries as the continuum theory. We analyze the mechanism behind this phenomenon for arbitrary dimension and gauge group representation. For this purpose we vary the number of lattice sites between even and odd parity in each single direction. Since the global symmetries are manifest in the lowest eigenvalues of the Dirac operator, the spectral statistics and also the symmetry breaking pattern will be affected. We analyze these effects and compare our predictions with Monte-Carlo simulations of naive Dirac operators in the strong coupling limit. This proceeding is a summary of our work [1].
Parity-violating hybridization in heavy Weyl semimetals
NASA Astrophysics Data System (ADS)
Chang, Po-Yao; Coleman, Piers
2018-04-01
We introduce a simple model to describe the formation of heavy Weyl semimetals in noncentrosymmetric heavy fermion compounds under the influence of a parity-mixing, onsite hybridization. A key aspect of interaction-driven heavy Weyl semimetals is the development of surface Kondo breakdown, which is expected to give rise to a temperature-dependent reconfiguration of the Fermi arcs and the Weyl cyclotron orbits which connect them via the chiral bulk states. Our theory predicts a strong temperature-dependent transformation in the quantum oscillations at low temperatures. In addition to the effects of surface Kondo breakdown, the renormalization effects in heavy Weyl semimetals will appear in a variety of thermodynamic and transport measurements.
Parity Anomaly and Spin Transmutation in Quantum Spin Hall Josephson Junctions.
Peng, Yang; Vinkler-Aviv, Yuval; Brouwer, Piet W; Glazman, Leonid I; von Oppen, Felix
2016-12-23
We study the Josephson effect in a quantum spin Hall system coupled to a localized magnetic impurity. As a consequence of the fermion parity anomaly, the spin of the combined system of impurity and spin-Hall edge alternates between half-integer and integer values when the superconducting phase difference across the junction advances by 2π. This leads to characteristic differences in the splittings of the spin multiplets by exchange coupling and single-ion anisotropy at phase differences, for which time-reversal symmetry is preserved. We discuss the resulting 8π-periodic (or Z_{4}) fractional Josephson effect in the context of recent experiments.
Six-dimensional regularization of chiral gauge theories
NASA Astrophysics Data System (ADS)
Fukaya, Hidenori; Onogi, Tetsuya; Yamamoto, Shota; Yamamura, Ryo
2017-03-01
We propose a regularization of four-dimensional chiral gauge theories using six-dimensional Dirac fermions. In our formulation, we consider two different mass terms having domain-wall profiles in the fifth and the sixth directions, respectively. A Weyl fermion appears as a localized mode at the junction of two different domain walls. One domain wall naturally exhibits the Stora-Zumino chain of the anomaly descent equations, starting from the axial U(1) anomaly in six dimensions to the gauge anomaly in four dimensions. Another domain wall implies a similar inflow of the global anomalies. The anomaly-free condition is equivalent to requiring that the axial U(1) anomaly and the parity anomaly are canceled among the six-dimensional Dirac fermions. Since our formulation is based on a massive vector-like fermion determinant, a nonperturbative regularization will be possible on a lattice. Putting the gauge field at the four-dimensional junction and extending it to the bulk using the Yang-Mills gradient flow, as recently proposed by Grabowska and Kaplan, we define the four-dimensional path integral of the target chiral gauge theory.
NASA Astrophysics Data System (ADS)
Yang, Li; Pu, Han
2016-09-01
We show that the wave function in one spatial sector x1
Constraints on parity violating conformal field theories in d = 3
NASA Astrophysics Data System (ADS)
Chowdhury, Subham Dutta; David, Justin R.; Prakash, Shiroman
2017-11-01
We derive constraints on three-point functions involving the stress tensor, T, and a conserved U(1) current, j, in 2+1 dimensional conformal field theories that violate parity, using conformal collider bounds introduced by Hofman and Maldacena. Conformal invariance allows parity-odd tensor-structures for the 〈 T T T〉 and 〈 jjT〉 correlation functions which are unique to three space-time dimensions. Let the parameters which determine the 〈 T T T〉 correlation function be t 4 and α T , where α T is the parity-violating contribution. Similarly let the parameters which determine 〈 jjT〉 correlation function be a 2, and α J , where α J is the parity-violating contribution. We show that the parameters ( t 4, α T ) and (a2, α J ) are bounded to lie inside a disc at the origin of the t 4 - α T plane and the a 2 - α J plane respectively. We then show that large N Chern-Simons theories coupled to a fundamental fermion/boson lie on the circle which bounds these discs. The `t Hooft coupling determines the location of these theories on the boundary circles.
Projective flatness in the quantisation of bosons and fermions
NASA Astrophysics Data System (ADS)
Wu, Siye
2015-07-01
We compare the quantisation of linear systems of bosons and fermions. We recall the appearance of projectively flat connection and results on parallel transport in the quantisation of bosons. We then discuss pre-quantisation and quantisation of fermions using the calculus of fermionic variables. We define a natural connection on the bundle of Hilbert spaces and show that it is projectively flat. This identifies, up to a phase, equivalent spinor representations constructed by various polarisations. We introduce the concept of metaplectic correction for fermions and show that the bundle of corrected Hilbert spaces is naturally flat. We then show that the parallel transport in the bundle of Hilbert spaces along a geodesic is a rescaled projection provided that the geodesic lies within the complement of a cut locus. Finally, we study the bundle of Hilbert spaces when there is a symmetry.
The Kitaev honeycomb model on surfaces of genus g ≥ 2
NASA Astrophysics Data System (ADS)
Brennan, John; Vala, Jiří
2018-05-01
We present a construction of the Kitaev honeycomb lattice model on an arbitrary higher genus surface. We first generalize the exact solution of the model based on the Jordan–Wigner fermionization to a surface with genus g = 2, and then use this as a basic module to extend the solution to lattices of arbitrary genus. We demonstrate our method by calculating the ground states of the model in both the Abelian doubled {Z}}}2 phase and the non-Abelian Ising topological phase on lattices with the genus up to g = 6. We verify the expected ground state degeneracy of the system in both topological phases and further illuminate the role of fermionic parity in the Abelian phase.
NASA Astrophysics Data System (ADS)
Ghapanvari, M.; Ghorashi, A. H.; Ranjbar, Z.; Jafarizadeh, M. A.
2018-03-01
In this article, the negative-parity states in the odd-mass 103 - 109Rh isotopes in terms of the sd and sdg interacting-boson fermion models were studied. The transitional interacting boson-fermion model Hamiltonians in sd and sdg-IBFM versions based on affine SU (1 , 1) Lie Algebra were employed to describe the evolution from the spherical to deformed gamma unstable shapes along with the chain of Rh isotopes. In this method, sdg-IBFM Hamiltonian, which is a three level pairing Hamiltonian was determined easily via the exactly solvable method. Some observables of the shape phase transitions such as energy levels, the two neutron separation energies, signature splitting of the γ-vibrational band, the α-decay and double β--decay energies were calculated and examined for these isotopes. The present calculation correctly reproduces the spherical to gamma-soft phase transition in the Rh isotopes. Some comparisons were made with sd-IBFM.
MESIC GROUP AND CONSERVATION OF PARITY (in French)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Petermann, A.; Ruegg, H.
1960-01-01
A principle of invariance under a continuous local group of transformations, the mesic group, is investigated. This principle has the following influences: 1. For the pseudoscslar Yukawa interaction of two Fermiore with the pseudoscalar pi -meson it entails PC invariance. 2. If the Fermions have equal bare masses with respect to electromagnetic interaction (a hypothesis which is plausible for the nucleons), the principle imposes, for the ps interaction with pi , the conservation of isotopic spin and separate P and C invariance. 3. For the Fermi interactions of the pairs (pn), nonconservation of parity. Arguments leading to this principle aremore » based on a generalization of the demonstration of the Dyson-Foldy equivalence theorem as given by Stueckelberg and Petermann. (auth)« less
NASA Astrophysics Data System (ADS)
Bonderson, Parsa; Lutchyn, Roman M.
2011-04-01
We propose computing bus devices that enable quantum information to be coherently transferred between topological and conventional qubits. We describe a concrete realization of such a topological quantum bus acting between a topological qubit in a Majorana wire network and a conventional semiconductor double quantum dot qubit. Specifically, this device measures the joint (fermion) parity of these two different qubits by using the Aharonov-Casher effect in conjunction with an ancilliary superconducting flux qubit that facilitates the measurement. Such a parity measurement, together with the ability to apply Hadamard gates to the two qubits, allows one to produce states in which the topological and conventional qubits are maximally entangled and to teleport quantum states between the topological and conventional quantum systems.
Calculation of K →π π decay amplitudes with improved Wilson fermion action in lattice QCD
NASA Astrophysics Data System (ADS)
Ishizuka, N.; Ishikawa, K.-I.; Ukawa, A.; Yoshié, T.
2015-10-01
We present our result for the K →π π decay amplitudes for both the Δ I =1 /2 and 3 /2 processes with the improved Wilson fermion action. Expanding on the earlier works by Bernard et al. and by Donini et al., we show that mixings with four-fermion operators with wrong chirality are absent even for the Wilson fermion action for the parity odd process in both channels due to CPS symmetry. Therefore, after subtraction of an effect from the lower dimensional operator, a calculation of the decay amplitudes is possible without complications from operators with wrong chirality, as for the case with chirally symmetric lattice actions. As a first step to verify the possibility of calculations with the Wilson fermion action, we consider the decay amplitudes at an unphysical quark mass mK˜2 mπ . Our calculations are carried out with Nf=2 +1 gauge configurations generated with the Iwasaki gauge action and nonperturbatively O (a )-improved Wilson fermion action at a =0.091 fm , mπ=280 MeV , and mK=580 MeV on a 323×64 (L a =2.9 fm ) lattice. For the quark loops in the penguin and disconnected contributions in the I =0 channel, the combined hopping parameter expansion and truncated solver method work very well for variance reduction. We obtain, for the first time with a Wilson-type fermion action, that Re A0=60 (36 )×1 0-8 GeV and Im A0=-67 (56 )×1 0-12 GeV for a matching scale q*=1 /a . The dependence on the matching scale q* for these values is weak.
Classification of compactified su( N c ) gauge theories with fermions in all representations
NASA Astrophysics Data System (ADS)
Anber, Mohamed M.; Vincent-Genod, Loïc
2017-12-01
We classify su( N c ) gauge theories on R^3× S^1 with massless fermions in higher representations obeying periodic boundary conditions along S^1 . In particular, we single out the class of theories that is asymptotically free and weakly coupled in the infrared, and therefore, is amenable to semi-classical treatment. Our study is conducted by carefully identifying the vacua inside the affine Weyl chamber using Verma bases and Frobenius formula techniques. Theories with fermions in pure representations are generally strongly coupled. The only exceptions are the four-index symmetric representation of su(2) and adjoint representation of su( N c ). However, we find a plethora of admissible theories with fermions in mixed representations. A sub-class of these theories have degenerate perturbative vacua separated by domain walls. In particular, su( N c ) theories with fermions in the mixed representations adjoint⊕fundamental and adjoint⊕two-index symmetric admit degenerate vacua that spontaneously break the parity P , charge conjugation C , and time reversal T symmetries. These are the first examples of strictly weakly coupled gauge theories on R^3× S^1 with spontaneously broken C , P , and T symmetries. We also compute the fermion zero modes in the background of monopole-instantons. The monopoles and their composites (topological molecules) proliferate in the vacuum leading to the confinement of electric charges. Interestingly enough, some theories have also accidental degenerate vacua, which are not related by any symmetry. These vacua admit different numbers of fermionic zero modes, and hence, different kinds of topological molecules. The lack of symmetry, however, indicates that such degeneracy might be lifted by higher order corrections. Finally, we study the general phase structure of adjoint⊕fundamental theories in the small circle and decompactification limits.
Beyond triplet: Unconventional superconductivity in a spin-3/2 topological semimetal
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kim, Hyunsoo; Wang, Kefeng; Nakajima, Yasuyuki
In all known fermionic super fluids, Cooper pairs are composed of spin-1/2 quasi-particles that pair to form either spin-singlet or spin-triplet bound states. The "spin" of a Bloch electron, however, is xed by the symmetries of the crystal and the atomic orbitals from which it is derived, and in some cases can behave as if it were a spin-3/2 particle. The superconducting state of such a system allows pairing beyond spin-triplet, with higher spin quasi-particles combining to form quintet or even septet pairs. Here, we report evidence of unconventional superconductivity emerging from a spin-3/2 quasiparticle electronic structure in the half-Heuslermore » semimetal YPtBi, a low-carrier density noncentrosymmetric cubic material with a high symmetry that preserves the p-like j = 3/2 manifold in the Bi-based Γ 8 band in the presence of strong spin-orbit coupling. With a striking linear temperature dependence of the London penetration depth, the existence of line nodes in the superconducting order parameter Δ is directly explained by a mixed-parity Cooper pairing model with high total angular momentum, consistent with a high-spin fermionic super fluid state. We propose a k ∙ p model of the j = 3/2 fermions to explain how a dominant J=3 septet pairing state is the simplest solution that naturally produces nodes in the mixed even-odd parity gap. Together with the underlying topologically non-trivial band structure, the unconventional pairing in this system represents a truly novel form of super fluidity that has strong potential for leading the development of a new generation of topological superconductors.« less
Beyond triplet: Unconventional superconductivity in a spin-3/2 topological semimetal
Kim, Hyunsoo; Wang, Kefeng; Nakajima, Yasuyuki; ...
2018-04-06
In all known fermionic super fluids, Cooper pairs are composed of spin-1/2 quasi-particles that pair to form either spin-singlet or spin-triplet bound states. The "spin" of a Bloch electron, however, is xed by the symmetries of the crystal and the atomic orbitals from which it is derived, and in some cases can behave as if it were a spin-3/2 particle. The superconducting state of such a system allows pairing beyond spin-triplet, with higher spin quasi-particles combining to form quintet or even septet pairs. Here, we report evidence of unconventional superconductivity emerging from a spin-3/2 quasiparticle electronic structure in the half-Heuslermore » semimetal YPtBi, a low-carrier density noncentrosymmetric cubic material with a high symmetry that preserves the p-like j = 3/2 manifold in the Bi-based Γ 8 band in the presence of strong spin-orbit coupling. With a striking linear temperature dependence of the London penetration depth, the existence of line nodes in the superconducting order parameter Δ is directly explained by a mixed-parity Cooper pairing model with high total angular momentum, consistent with a high-spin fermionic super fluid state. We propose a k ∙ p model of the j = 3/2 fermions to explain how a dominant J=3 septet pairing state is the simplest solution that naturally produces nodes in the mixed even-odd parity gap. Together with the underlying topologically non-trivial band structure, the unconventional pairing in this system represents a truly novel form of super fluidity that has strong potential for leading the development of a new generation of topological superconductors.« less
NASA Astrophysics Data System (ADS)
Monthus, Cécile
2018-06-01
For random interacting Majorana models where the only symmetries are the parity P and the time-reversal-symmetry T, various approaches are compared to construct exact even and odd normalized zero modes Γ in finite size, i.e. Hermitian operators that commute with the Hamiltonian, that square to the identity, and that commute (even) or anticommute (odd) with the parity P. Even normalized zero-modes are well known under the name of ‘pseudo-spins’ in the field of many-body-localization or more precisely ‘local integrals of motion’ (LIOMs) in the many-body-localized-phase where the pseudo-spins happens to be spatially localized. Odd normalized zero-modes are popular under the name of ‘Majorana zero modes’ or ‘strong zero modes’. Explicit examples for small systems are described in detail. Applications to real-space renormalization procedures based on blocks containing an odd number of Majorana fermions are also discussed.
Three-Dimensional Majorana Fermions in Chiral Superconductors
NASA Astrophysics Data System (ADS)
Kozii, Vladyslav; Venderbos, Jorn; Fu, Liang
Through a systematic symmetry and topology analysis we establish that three-dimensional chiral superconductors with strong spin-orbit coupling and odd-parity pairing generically host low-energy nodal quasiparticles that are spin-non-degenerate and realize Majorana fermions in three dimensions. By examining all types of chiral Cooper pairs with total angular momentum J formed by Bloch electrons with angular momentum j in crystals, we obtain a comprehensive classification of gapless Majorana quasiparticles in terms of energy-momentum relation and location on the Fermi surface. We show that the existence of bulk Majorana fermions in the vicinity of spin-selective point nodes is rooted in the non-unitary nature of chiral pairing in spin-orbit-coupled superconductors. We address experimental signatures of Majorana fermions, and find that the nuclear magnetic resonance spin relaxation rate is significantly suppressed for nuclear spins polarized along the nodal direction as a consequence of the spin-selective Majorana nature of nodal quasiparticles. Furthermore, Majorana nodes in the bulk have nontrivial topology and imply the presence of Majorana bound states on the surface that form arcs in momentum space. This work is supported by DOE Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award de-sc0010526 (LF and VK), and the Netherlands Organization for Scientific Research (NWO) through a Rubicon Grant (JV).
Baryon currents in QCD with compact dimensions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lucini, B.; Patella, A.; Istituto Nazionale Fisica Nucleare Sezione di Pisa, Largo Pontecorvo 3, 56126 Pisa
2007-06-15
On a compact space with nontrivial cycles, for sufficiently small values of the radii of the compact dimensions, SU(N) gauge theories coupled with fermions in the fundamental representation spontaneously break charge conjugation, time reversal, and parity. We show at one loop in perturbation theory that a physical signature for this phenomenon is a nonzero baryonic current wrapping around the compact directions. The persistence of this current beyond the perturbative regime is checked by lattice simulations.
Bonderson, Parsa; Lutchyn, Roman M
2011-04-01
We propose computing bus devices that enable quantum information to be coherently transferred between topological and conventional qubits. We describe a concrete realization of such a topological quantum bus acting between a topological qubit in a Majorana wire network and a conventional semiconductor double quantum dot qubit. Specifically, this device measures the joint (fermion) parity of these two different qubits by using the Aharonov-Casher effect in conjunction with an ancilliary superconducting flux qubit that facilitates the measurement. Such a parity measurement, together with the ability to apply Hadamard gates to the two qubits, allows one to produce states in which the topological and conventional qubits are maximally entangled and to teleport quantum states between the topological and conventional quantum systems. © 2011 American Physical Society
Bose-Fermi symmetry in the odd-even gold isotopes
NASA Astrophysics Data System (ADS)
Thomas, T.; Régis, J.-M.; Jolie, J.; Heinze, S.; Albers, M.; Bernards, C.; Fransen, C.; Radeck, D.
2014-05-01
In this work the results of an in-beam experiment on 195Au are presented, yielding new spins, multipole mixing ratios, and new low-lying states essential for the understanding of this nucleus. The positive-parity states from this work together with compiled data from the available literature for 185-199Au are compared to Interacting Boson Fermion Model calculations employing the Spin(6) Bose-Fermi symmetry. The evolution of the parameters for the τ splitting and the J splitting reveals a smooth behavior. Thereby, a common description based on the Bose-Fermi symmetry is found for 189-199Au. Furthermore, the calculated E2 transition strengths are compared to experimental values with fixed effective boson and fermion charges for all odd-even gold isotopes, emphasizing that the Spin(6) Bose-Fermi symmetry is valid for the gold isotopes.
Topological Superfluid and Majorana Zero Modes in Synthetic Dimension
Yan, Zhongbo; Wan, Shaolong; Wang, Zhong
2015-01-01
Recently it has been shown that multicomponent spin-orbit-coupled fermions in one-dimensional optical lattices can be viewed as spinless fermions moving in two-dimensional synthetic lattices with synthetic magnetic flux. The quantum Hall edge states in these systems have been observed in recent experiments. In this paper we study the effect of an attractive Hubbard interaction. Since the Hubbard interaction is long-range in the synthetic dimension, it is able to efficiently induce Cooper pairing between the counterpropagating chiral edge states. The topological class of the resultant one-dimensional superfluid is determined by the parity (even/odd) of the Chern number in the two-dimensional synthetic lattice. We also show the presence of a chiral symmetry in our model, which implies Z classification and the robustness of multiple zero modes when this symmetry is unbroken. PMID:26515084
Dynamical Electroweak Symmetry Breaking with a Heavy Fermion in Light of Recent LHC Results
Hung, Pham Q.
2013-01-01
The recent announcement of a discovery of a possible Higgs-like particle—its spin and parity are yet to be determined—at the LHC with a mass of 126 GeV necessitates a fresh look at the nature of the electroweak symmetry breaking, in particular if this newly-discovered particle will turn out to have the quantum numbers of a Standard Model Higgs boson. Even if it were a 0 + scalar with the properties expected for a SM Higgs boson, there is still the quintessential hierarchy problem that one has to deal with and which, by itself, suggests a new physics energy scale around 1 TeV.more » This paper presents a minireview of one possible scenario: the formation of a fermion-antifermion condensate coming from a very heavy fourth generation, carrying the quantum number of the SM Higgs field, and thus breaking the electroweak symmetry.« less
Exotic meson decays in the environment with chiral imbalance
NASA Astrophysics Data System (ADS)
Andrianov, A. A.; Andrianov, V. A.; Espriu, D.; Iakubovich, A. V.; Putilova, A. E.
2017-10-01
An emergence of Local Parity Breaking (LPB) in central heavy-ion collisions (HIC) at high energies is discussed. LPB in the fireball can be produced by a difference between the number densities of right- and left-handed chiral fermions (Chiral Imbalance) which is implemented by a chiral (axial) chemical potential. The effective meson lagrangian induced by QCD is extended to the medium with Chiral Imbalance and the properties of light scalar and pseudoscalar mesons (π, α0) are analyzed. It is shown that exotic decays of scalar mesons arise as a result of mixing of π and α0 vacuum states in the presence of chiral imbalance. The pion electromagnetic formfactor obtains an unusual parity-odd supplement which generates a photon polarization asymmetry in pion polarizability. We hope that the above pointed indications of LPB can be identified in experiments on LHC, RHIC, CBM FAIR and NICA accelerators.
Helical modes generate antimagnetic rotational spectra in nuclei
NASA Astrophysics Data System (ADS)
Malik, Sham S.
2018-03-01
A systematic analysis of the antimagnetic rotation band using r -helicity formalism is carried out for the first time. The observed octupole correlation in a nucleus is likely to play a role in establishing the antimagnetic spectrum. Such octupole correlations are explained within the helical orbits. In a rotating field, two identical fermions (generally protons) with paired spins generate these helical orbits in such a way that its positive (i.e., up) spin along the axis of quantization refers to one helicity (right-handedness) while negative (down) spin along the same quantization-axis decides another helicity (left-handedness). Since the helicity remains invariant under rotation, therefore, the quantum state of a fermion is represented by definite angular momentum and helicity. These helicity represented states support a pear-shaped structure of a rotating system having z axis as the symmetry axis. A combined operation of parity, time-reversal, and signature symmetries ensures an absence of one of the signature partner band from the observed antimagnetic spectrum. This formalism has also been tested for the recently observed negative parity Δ I =2 antimagnetic spectrum in odd-A 101Pd nucleus and explains nicely its energy spectrum as well as the B (E 2 ) values. Further, this formalism is found to be fully consistent with twin-shears mechanism popularly known for such type of rotational bands. It also provides significant clue for extending these experiments in various mass regions spread over the nuclear chart.
ERIC Educational Resources Information Center
Lasonen, Johanna, Ed.
This book contains the following papers on the Leonardo da Vinci project: "Looking for Post-16 Education Strategies for Parity of Esteem in Europe" (Lasonen); "Improving Parity of Esteem as a Policy Goal" (Makinen, Volanen); "Alternative Strategies for Parity of Esteem between General/Academic and Vocational Education in…
Persistent current and zero-energy Majorana modes in a p -wave disordered superconducting ring
NASA Astrophysics Data System (ADS)
Nava, Andrea; Giuliano, Rosa; Campagnano, Gabriele; Giuliano, Domenico
2017-04-01
We discuss the emergence of zero-energy Majorana modes in a disordered finite-length p -wave one-dimensional superconducting ring, pierced by a magnetic flux Φ tuned at an appropriate value Φ =Φ* . In the absence of fermion parity conservation, we evidence the emergence of the Majorana modes by looking at the discontinuities in the persistent current I [Φ ] at Φ =Φ* . By monitoring the discontinuities in I [Φ ] , we map out the region in parameter space characterized by the emergence of Majorana modes in the disordered ring.
NASA Astrophysics Data System (ADS)
Gu, Pei-Hong
2017-10-01
We introduce a mirror copy of the ordinary fermions and Higgs scalars for embedding the SU(2) L × U(1) Y electroweak gauge symmetry into an SU(2) L × SU(2) R × U(1) B-L left-right gauge symmetry. We then show the spontaneous left-right symmetry breaking can automatically break the parity symmetry motivated by solving the strong CP problem. Through the SU(2) R gauge interactions, a mirror Majorana neutrino can decay into a mirror charged lepton and two mirror quarks. Consequently we can obtain a lepton asymmetry stored in the mirror charged leptons. The Yukawa couplings of the mirror and ordinary charged fermions to a dark matter scalar then can transfer the mirror lepton asymmetry to an ordinary lepton asymmetry which provides a solution to the cosmic baryon asymmetry in association with the SU(2) L sphaleron processes. In this scenario, the baryon asymmetry can be well described by the neutrino mass matrix up to an overall factor.
NASA Astrophysics Data System (ADS)
Pu, Songyang; Wu, Ying-Hai; Jain, J. K.
2017-11-01
We achieve an explicit construction of the lowest Landau level (LLL) projected wave functions for composite fermions in the periodic (torus) geometry. To this end, we first demonstrate how the vortex attachment of the composite fermion (CF) theory can be accomplished in the torus geometry to produce the "unprojected" wave functions satisfying the correct (quasi)periodic boundary conditions. We then consider two methods for projecting these wave functions into the LLL. The direct projection produces valid wave functions but can be implemented only for very small systems. The more powerful and more useful projection method of Jain and Kamilla fails in the torus geometry because it does not preserve the periodic boundary conditions and thus takes us out of the original Hilbert space. We have succeeded in constructing a modified projection method that is consistent with both the periodic boundary conditions and the general structure of the CF theory. This method is valid for a large class of states of composite fermions, called "proper states," which includes the incompressible ground states at electron filling factors ν =n/2 p n +1 , their charged and neutral excitations, and also the quasidegenerate ground states at arbitrary filling factors of the form ν =ν/*2pν*+1 , where n and p are integers and ν* is the CF filling factor. Comparison with exact results known for small systems for the ground and excited states at filling factors ν =1 /3 , 2/5, and 3/7 demonstrates our LLL-projected wave functions to be extremely accurate representations of the actual Coulomb eigenstates. Our construction enables the study of large systems of composite fermions on the torus, thereby opening the possibility of investigating numerous interesting questions and phenomena.
Yamamoto, Arata
2016-07-29
We propose the lattice QCD calculation of the Berry phase, which is defined by the ground state of a single fermion. We perform the ground-state projection of a single-fermion propagator, construct the Berry link variable on a momentum-space lattice, and calculate the Berry phase. As the first application, the first Chern number of the (2+1)-dimensional Wilson fermion is calculated by the Monte Carlo simulation.
A Clifford algebra approach to chiral symmetry breaking and fermion mass hierarchies
NASA Astrophysics Data System (ADS)
Lu, Wei
2017-09-01
We propose a Clifford algebra approach to chiral symmetry breaking and fermion mass hierarchies in the context of composite Higgs bosons. Standard model fermions are represented by algebraic spinors of six-dimensional binary Clifford algebra, while ternary Clifford algebra-related flavor projection operators control allowable flavor-mixing interactions. There are three composite electroweak Higgs bosons resulted from top quark, tau neutrino, and tau lepton condensations. Each of the three condensations gives rise to masses of four different fermions. The fermion mass hierarchies within these three groups are determined by four-fermion condensations, which break two global chiral symmetries. The four-fermion condensations induce axion-like pseudo-Nambu-Goldstone bosons and can be dark matter candidates. In addition to the 125 GeV Higgs boson observed at the Large Hadron Collider, we anticipate detection of tau neutrino composite Higgs boson via the charm quark decay channel.
Fermionic topological quantum states as tensor networks
NASA Astrophysics Data System (ADS)
Wille, C.; Buerschaper, O.; Eisert, J.
2017-06-01
Tensor network states, and in particular projected entangled pair states, play an important role in the description of strongly correlated quantum lattice systems. They do not only serve as variational states in numerical simulation methods, but also provide a framework for classifying phases of quantum matter and capture notions of topological order in a stringent and rigorous language. The rapid development in this field for spin models and bosonic systems has not yet been mirrored by an analogous development for fermionic models. In this work, we introduce a tensor network formalism capable of capturing notions of topological order for quantum systems with fermionic components. At the heart of the formalism are axioms of fermionic matrix-product operator injectivity, stable under concatenation. Building upon that, we formulate a Grassmann number tensor network ansatz for the ground state of fermionic twisted quantum double models. A specific focus is put on the paradigmatic example of the fermionic toric code. This work shows that the program of describing topologically ordered systems using tensor networks carries over to fermionic models.
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2010-03-04
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The structure of 193Au within the Interacting Boson Fermion Model
NASA Astrophysics Data System (ADS)
Thomas, T.; Bernards, C.; Régis, J.-M.; Albers, M.; Fransen, C.; Jolie, J.; Heinze, S.; Radeck, D.; Warr, N.; Zell, K.-O.
2014-02-01
A γγ angular correlation experiment investigating the nucleus 193Au is presented. In this work the level scheme of 193Au is extended by new level information on spins, multipolarities and newly observed states. The new results are compared with theoretical predictions from a general Interacting Boson Fermion Model (IBFM) calculation for the positive-parity states. The experimental data is in good agreement with an IBFM calculation using all proton orbitals between the shell closures at Z=50 and Z=126. As a dominant contribution of the d orbital to the wave function of the lowest excited states is observed, a truncated model of the IBFM using a Bose-Fermi symmetry is applied to the describe 193Au. Using the parameters of a fit performed for 193Au, the level scheme of 192Pt, the supersymmetric partner of 193Au, is predicted but shows a too small boson seniority splitting. We obtained a common fit by including states observed in 192Pt. With the new parameters a supersymmetric description of both nuclei is established.
Top quark rare decays via loop-induced FCNC interactions in extended mirror fermion model
NASA Astrophysics Data System (ADS)
Hung, P. Q.; Lin, Yu-Xiang; Nugroho, Chrisna Setyo; Yuan, Tzu-Chiang
2018-02-01
Flavor changing neutral current (FCNC) interactions for a top quark t decays into Xq with X represents a neutral gauge or Higgs boson, and q a up- or charm-quark are highly suppressed in the Standard Model (SM) due to the Glashow-Iliopoulos-Miami mechanism. Whilst current limits on the branching ratios of these processes have been established at the order of 10-4 from the Large Hadron Collider experiments, SM predictions are at least nine orders of magnitude below. In this work, we study some of these FCNC processes in the context of an extended mirror fermion model, originally proposed to implement the electroweak scale seesaw mechanism for non-sterile right-handed neutrinos. We show that one can probe the process t → Zc for a wide range of parameter space with branching ratios varying from 10-6 to 10-8, comparable with various new physics models including the general two Higgs doublet model with or without flavor violations at tree level, minimal supersymmetric standard model with or without R-parity, and extra dimension model.
NASA Astrophysics Data System (ADS)
Zhao, Yumin
1997-07-01
By the techniques of the Wick theorem for coupled clusters, the no-energy-weighted electromagnetic sum-rule calculations are presented in the sdg neutron-proton interacting boson model, the nuclear pair shell model and the fermion-dynamical symmetry model. The project supported by Development Project Foundation of China, National Natural Science Foundation of China, Doctoral Education Fund of National Education Committee, Fundamental Research Fund of Southeast University
Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector.
Aad, G; Abbott, B; Abdallah, J; Abdinov, O; Aben, R; Abolins, M; AbouZeid, O S; Abramowicz, H; Abreu, H; Abreu, R; Abulaiti, Y; Acharya, B S; Adamczyk, L; Adams, D L; Adelman, J; Adomeit, S; Adye, T; Affolder, A A; Agatonovic-Jovin, T; Agricola, J; Aguilar-Saavedra, J A; Ahlen, S P; Ahmadov, F; Aielli, G; Akerstedt, H; Åkesson, T P A; Akimov, A V; Alberghi, G L; Albert, J; Albrand, S; Alconada Verzini, M J; Aleksa, M; Aleksandrov, I N; Alexa, C; Alexander, G; Alexopoulos, T; Alhroob, M; Alimonti, G; Alio, L; Alison, J; Alkire, S P; Allbrooke, B M M; Allport, P P; Aloisio, A; Alonso, A; Alonso, F; Alpigiani, C; Altheimer, A; Alvarez Gonzalez, B; Álvarez Piqueras, D; Alviggi, M G; Amadio, B T; Amako, K; Amaral Coutinho, Y; Amelung, C; Amidei, D; Amor Dos Santos, S P; Amorim, A; Amoroso, S; Amram, N; Amundsen, G; Anastopoulos, C; Ancu, L S; Andari, N; Andeen, T; Anders, C F; Anders, G; Anders, J K; Anderson, K J; Andreazza, A; Andrei, V; Angelidakis, S; Angelozzi, I; Anger, P; Angerami, A; Anghinolfi, F; Anisenkov, A V; Anjos, N; Annovi, A; Antonelli, M; Antonov, A; Antos, J; Anulli, F; Aoki, M; Aperio Bella, L; Arabidze, G; Arai, Y; Araque, J P; Arce, A T H; Arduh, F A; Arguin, J-F; Argyropoulos, S; Arik, M; Armbruster, A J; Arnaez, O; Arnal, V; Arnold, H; Arratia, M; Arslan, O; Artamonov, A; Artoni, G; Asai, S; Asbah, N; Ashkenazi, A; Åsman, B; Asquith, L; Assamagan, K; Astalos, R; Atkinson, M; Atlay, N B; Auerbach, B; Augsten, K; Aurousseau, M; Avolio, G; Axen, B; Ayoub, M K; Azuelos, G; Baak, M A; Baas, A E; Bacci, C; Bachacou, H; Bachas, K; Backes, M; Backhaus, M; Bagiacchi, P; Bagnaia, P; Bai, Y; Bain, T; Baines, J T; Baker, O K; Baldin, E M; Balek, P; Balestri, T; Balli, F; Banas, E; Banerjee, Sw; Bannoura, A A E; Bansil, H S; Barak, L; Barberio, E L; Barberis, D; Barbero, M; Barillari, T; Barisonzi, M; Barklow, T; Barlow, N; Barnes, S L; Barnett, B M; Barnett, R M; Barnovska, Z; Baroncelli, A; Barone, G; Barr, A J; Barreiro, F; Barreiro Guimarães da Costa, J; Bartoldus, R; Barton, A E; Bartos, P; Basalaev, A; Bassalat, A; Basye, A; Bates, R L; Batista, S J; Batley, J R; Battaglia, M; Bauce, M; Bauer, F; Bawa, H S; Beacham, J B; Beattie, M D; Beau, T; Beauchemin, P H; Beccherle, R; Bechtle, P; Beck, H P; Becker, K; Becker, M; Becker, S; Beckingham, M; Becot, C; Beddall, A J; Beddall, A; Bednyakov, V A; Bee, C P; Beemster, L J; Beermann, T A; Begel, M; Behr, J K; Belanger-Champagne, C; Bell, W H; Bella, G; Bellagamba, L; Bellerive, A; Bellomo, M; Belotskiy, K; Beltramello, O; Benary, O; Benchekroun, D; Bender, M; Bendtz, K; Benekos, N; Benhammou, Y; Benhar Noccioli, E; Benitez Garcia, J A; Benjamin, D P; Bensinger, J R; Bentvelsen, S; Beresford, L; Beretta, M; Berge, D; Bergeaas Kuutmann, E; Berger, N; Berghaus, F; Beringer, J; Bernard, C; Bernard, N R; Bernius, C; Bernlochner, F U; Berry, T; Berta, P; Bertella, C; Bertoli, G; Bertolucci, F; Bertsche, C; Bertsche, D; Besana, M I; Besjes, G J; Bessidskaia Bylund, O; Bessner, M; Besson, N; Betancourt, C; Bethke, S; Bevan, A J; Bhimji, W; Bianchi, R M; Bianchini, L; Bianco, M; Biebel, O; Biedermann, D; Bieniek, S P; Biglietti, M; Bilbao De Mendizabal, J; Bilokon, H; Bindi, M; Binet, S; Bingul, A; Bini, C; Biondi, S; Black, C W; Black, J E; Black, K M; Blackburn, D; Blair, R E; Blanchard, J-B; Blanco, J E; Blazek, T; Bloch, I; Blocker, C; Blum, W; Blumenschein, U; Bobbink, G J; Bobrovnikov, V S; Bocchetta, S S; Bocci, A; Bock, C; Boehler, M; Bogaerts, J A; Bogavac, D; Bogdanchikov, A G; Bohm, C; Boisvert, V; Bold, T; Boldea, V; Boldyrev, A S; Bomben, M; Bona, M; Boonekamp, M; Borisov, A; Borissov, G; Borroni, S; Bortfeldt, J; Bortolotto, V; Bos, K; Boscherini, D; Bosman, M; Boudreau, J; Bouffard, J; Bouhova-Thacker, E V; Boumediene, D; Bourdarios, C; Bousson, N; Boveia, A; Boyd, J; Boyko, I R; Bozic, I; Bracinik, J; Brandt, A; Brandt, G; Brandt, O; Bratzler, U; Brau, B; Brau, J E; Braun, H M; Brazzale, S F; Breaden Madden, W D; Brendlinger, K; Brennan, A J; Brenner, L; Brenner, R; Bressler, S; Bristow, K; Bristow, T M; Britton, D; Britzger, D; Brochu, F M; Brock, I; Brock, R; Bronner, J; Brooijmans, G; Brooks, T; Brooks, W K; Brosamer, J; Brost, E; Brown, J; Bruckman de Renstrom, P A; Bruncko, D; Bruneliere, R; Bruni, A; Bruni, G; Bruschi, M; Bruscino, N; Bryngemark, L; Buanes, T; Buat, Q; Buchholz, P; Buckley, A G; Buda, S I; Budagov, I A; Buehrer, F; Bugge, L; Bugge, M K; Bulekov, O; Bullock, D; Burckhart, H; Burdin, S; Burghgrave, B; Burke, S; Burmeister, I; Busato, E; Büscher, D; Büscher, V; Bussey, P; Butler, J M; Butt, A I; Buttar, C M; Butterworth, J M; Butti, P; Buttinger, W; Buzatu, A; Buzykaev, A R; Cabrera Urbán, S; Caforio, D; Cairo, V M; Cakir, O; Calafiura, P; Calandri, A; Calderini, G; Calfayan, P; Caloba, L P; Calvet, D; Calvet, S; Camacho Toro, R; Camarda, S; Camarri, P; Cameron, D; Caminal Armadans, R; Campana, S; Campanelli, M; Campoverde, A; Canale, V; Canepa, A; Cano Bret, M; Cantero, J; Cantrill, R; Cao, T; Capeans Garrido, M D M; Caprini, I; Caprini, M; Capua, M; Caputo, R; Cardarelli, R; Cardillo, F; Carli, T; Carlino, G; Carminati, L; Caron, S; Carquin, E; Carrillo-Montoya, G D; Carter, J R; Carvalho, J; Casadei, D; Casado, M P; Casolino, M; Castaneda-Miranda, E; Castelli, A; Castillo Gimenez, V; Castro, N F; Catastini, P; Catinaccio, A; Catmore, J R; Cattai, A; Caudron, J; Cavaliere, V; Cavalli, D; Cavalli-Sforza, M; Cavasinni, V; Ceradini, F; Cerio, B C; Cerny, K; Cerqueira, A S; Cerri, A; Cerrito, L; Cerutti, F; Cerv, M; Cervelli, A; Cetin, S A; Chafaq, A; Chakraborty, D; Chalupkova, I; Chang, P; Chapman, J D; Charlton, D G; Chau, C C; Chavez Barajas, C A; Cheatham, S; Chegwidden, A; Chekanov, S; Chekulaev, S V; Chelkov, G A; Chelstowska, M A; Chen, C; Chen, H; Chen, K; Chen, L; Chen, S; Chen, X; Chen, Y; Cheng, H C; Cheng, Y; Cheplakov, A; Cheremushkina, E; Cherkaoui El Moursli, R; Chernyatin, V; Cheu, E; Chevalier, L; Chiarella, V; Childers, J T; Chiodini, G; Chisholm, A S; Chislett, R T; Chitan, A; Chizhov, M V; Choi, K; Chouridou, S; Chow, B K B; Christodoulou, V; Chromek-Burckhart, D; Chudoba, J; Chuinard, A J; Chwastowski, J J; Chytka, L; Ciapetti, G; Ciftci, A K; Cinca, D; Cindro, V; Cioara, I A; Ciocio, A; Cirotto, F; Citron, Z H; Ciubancan, M; Clark, A; Clark, B L; Clark, P J; Clarke, R N; Cleland, W; Clement, C; Coadou, Y; Cobal, M; Coccaro, A; Cochran, J; Coffey, L; Cogan, J G; Cole, B; Cole, S; Colijn, A P; Collot, J; Colombo, T; Compostella, G; Conde Muiño, P; Coniavitis, E; Connell, S H; Connelly, I A; Consonni, S M; Consorti, V; Constantinescu, S; Conta, C; Conti, G; Conventi, F; Cooke, M; Cooper, B D; Cooper-Sarkar, A M; Cornelissen, T; Corradi, M; Corriveau, F; Corso-Radu, A; Cortes-Gonzalez, A; Cortiana, G; Costa, G; Costa, M J; Costanzo, D; Côté, D; Cottin, G; Cowan, G; Cox, B E; Cranmer, K; Cree, G; Crépé-Renaudin, S; Crescioli, F; Cribbs, W A; Crispin Ortuzar, M; Cristinziani, M; Croft, V; Crosetti, G; Cuhadar Donszelmann, T; Cummings, J; Curatolo, M; Cuthbert, C; Czirr, H; Czodrowski, P; D'Auria, S; D'Onofrio, M; Da Cunha Sargedas De Sousa, M J; Da Via, C; Dabrowski, W; Dafinca, A; Dai, T; Dale, O; Dallaire, F; Dallapiccola, C; Dam, M; Dandoy, J R; Dang, N P; Daniells, A C; Danninger, M; Dano Hoffmann, M; Dao, V; Darbo, G; Darmora, S; Dassoulas, J; Dattagupta, A; Davey, W; David, C; Davidek, T; Davies, E; Davies, M; Davison, P; Davygora, Y; Dawe, E; Dawson, I; Daya-Ishmukhametova, R K; De, K; de Asmundis, R; De Castro, S; De Cecco, S; De Groot, N; de Jong, P; De la Torre, H; De Lorenzi, F; De Nooij, L; De Pedis, D; De Salvo, A; De Sanctis, U; De Santo, A; De Vivie De Regie, J B; Dearnaley, W J; Debbe, R; Debenedetti, C; Dedovich, D V; Deigaard, I; Del Peso, J; Del Prete, T; Delgove, D; Deliot, F; Delitzsch, C M; Deliyergiyev, M; Dell'Acqua, A; Dell'Asta, L; Dell'Orso, M; Della Pietra, M; Della Volpe, D; Delmastro, M; Delsart, P A; Deluca, C; DeMarco, D A; Demers, S; Demichev, M; Demilly, A; Denisov, S P; Derendarz, D; Derkaoui, J E; Derue, F; Dervan, P; Desch, K; Deterre, C; Deviveiros, P O; Dewhurst, A; Dhaliwal, S; Di Ciaccio, A; Di Ciaccio, L; Di Domenico, A; Di Donato, C; Di Girolamo, A; Di Girolamo, B; Di Mattia, A; Di Micco, B; Di Nardo, R; Di Simone, A; Di Sipio, R; Di Valentino, D; Diaconu, C; Diamond, M; Dias, F A; Diaz, M A; Diehl, E B; Dietrich, J; Diglio, S; Dimitrievska, A; Dingfelder, J; Dita, P; Dita, S; Dittus, F; Djama, F; Djobava, T; Djuvsland, J I; do Vale, M A B; Dobos, D; Dobre, M; Doglioni, C; Dohmae, T; Dolejsi, J; Dolezal, Z; Dolgoshein, B A; Donadelli, M; Donati, S; Dondero, P; Donini, J; Dopke, J; Doria, A; Dova, M T; Doyle, A T; Drechsler, E; Dris, M; Dubreuil, E; Duchovni, E; Duckeck, G; Ducu, O A; Duda, D; Dudarev, A; Duflot, L; Duguid, L; Dührssen, M; Dunford, M; Duran Yildiz, H; Düren, M; Durglishvili, A; Duschinger, D; Dyndal, M; Eckardt, C; Ecker, K M; Edgar, R C; Edson, W; Edwards, N C; Ehrenfeld, W; Eifert, T; Eigen, G; Einsweiler, K; Ekelof, T; El Kacimi, M; Ellert, M; Elles, S; Ellinghaus, F; Elliot, A A; Ellis, N; Elmsheuser, J; Elsing, M; Emeliyanov, D; Enari, Y; Endner, O C; Endo, M; Erdmann, J; Ereditato, A; Ernis, G; Ernst, J; Ernst, M; Errede, S; Ertel, E; Escalier, M; Esch, H; Escobar, C; Esposito, B; Etienvre, A I; Etzion, E; Evans, H; Ezhilov, A; Fabbri, L; Facini, G; Fakhrutdinov, R M; Falciano, S; Falla, R J; Faltova, J; Fang, Y; Fanti, M; Farbin, A; Farilla, A; Farooque, T; Farrell, S; Farrington, S M; Farthouat, P; Fassi, F; Fassnacht, P; Fassouliotis, D; Faucci Giannelli, M; Favareto, A; Fayard, L; Federic, P; Fedin, O L; Fedorko, W; Feigl, S; Feligioni, L; Feng, C; Feng, E J; Feng, H; Fenyuk, A B; Feremenga, L; Fernandez Martinez, P; Fernandez Perez, S; Ferrando, J; Ferrari, A; Ferrari, P; Ferrari, R; Ferreira de Lima, D E; Ferrer, A; Ferrere, D; Ferretti, C; Ferretto Parodi, A; Fiascaris, M; Fiedler, F; Filipčič, A; Filipuzzi, M; Filthaut, F; Fincke-Keeler, M; Finelli, K D; Fiolhais, M C N; Fiorini, L; Firan, A; Fischer, A; Fischer, C; Fischer, J; Fisher, W C; Fitzgerald, E A; Flaschel, N; Fleck, I; Fleischmann, P; Fleischmann, S; Fletcher, G T; Fletcher, G; Fletcher, R R M; Flick, T; Floderus, A; Flores Castillo, L R; Flowerdew, M J; Formica, A; Forti, A; Fournier, D; Fox, H; Fracchia, S; Francavilla, P; Franchini, M; Francis, D; Franconi, L; Franklin, M; Frate, M; Fraternali, M; Freeborn, D; French, S T; Friedrich, F; Froidevaux, D; Frost, J A; Fukunaga, C; Fullana Torregrosa, E; Fulsom, B G; Fuster, J; Gabaldon, C; Gabizon, O; Gabrielli, A; Gabrielli, A; Gadatsch, S; Gadomski, S; Gagliardi, G; Gagnon, P; Galea, C; Galhardo, B; Gallas, E J; Gallop, B J; Gallus, P; Galster, G; Gan, K K; Gao, J; Gao, Y; Gao, Y S; Garay Walls, F M; Garberson, F; García, C; García Navarro, J E; Garcia-Sciveres, M; Gardner, R W; Garelli, N; Garonne, V; Gatti, C; Gaudiello, A; Gaudio, G; Gaur, B; Gauthier, L; Gauzzi, P; Gavrilenko, I L; Gay, C; Gaycken, G; Gazis, E N; Ge, P; Gecse, Z; Gee, C N P; Geerts, D A A; Geich-Gimbel, Ch; Geisler, M P; Gemme, C; Genest, M H; Gentile, S; George, M; George, S; Gerbaudo, D; Gershon, A; Ghasemi, S; Ghazlane, H; Giacobbe, B; Giagu, S; Giangiobbe, V; Giannetti, P; Gibbard, B; Gibson, S M; Gilchriese, M; Gillam, T P S; Gillberg, D; Gilles, G; Gingrich, D M; Giokaris, N; Giordani, M P; Giorgi, F M; Giorgi, F M; Giraud, P F; Giromini, P; Giugni, D; Giuliani, C; Giulini, M; Gjelsten, B K; Gkaitatzis, S; Gkialas, I; Gkougkousis, E L; Gladilin, L K; Glasman, C; Glatzer, J; Glaysher, P C F; Glazov, A; Goblirsch-Kolb, M; Goddard, J R; Godlewski, J; Goldfarb, S; Golling, T; Golubkov, D; Gomes, A; Gonçalo, R; Goncalves Pinto Firmino Da Costa, J; Gonella, L; González de la Hoz, S; Gonzalez Parra, G; Gonzalez-Sevilla, S; Goossens, L; Gorbounov, P A; Gordon, H A; Gorelov, I; Gorini, B; Gorini, E; Gorišek, A; Gornicki, E; Goshaw, A T; Gössling, C; Gostkin, M I; Goujdami, D; Goussiou, A G; Govender, N; Gozani, E; Grabas, H M X; Graber, L; Grabowska-Bold, I; Grafström, P; Grahn, K-J; Gramling, J; Gramstad, E; Grancagnolo, S; Grassi, V; Gratchev, V; Gray, H M; Graziani, E; Greenwood, Z D; Gregersen, K; Gregor, I M; Grenier, P; Griffiths, J; Grillo, A A; Grimm, K; Grinstein, S; Gris, Ph; Grivaz, J-F; Grohs, J P; Grohsjean, A; Gross, E; Grosse-Knetter, J; Grossi, G C; Grout, Z J; Guan, L; Guenther, J; Guescini, F; Guest, D; Gueta, O; Guido, E; Guillemin, T; Guindon, S; Gul, U; Gumpert, C; Guo, J; Guo, Y; Gupta, S; Gustavino, G; Gutierrez, P; Gutierrez Ortiz, N G; Gutschow, C; Guyot, C; Gwenlan, C; Gwilliam, C B; Haas, A; Haber, C; Hadavand, H K; Haddad, N; Haefner, P; Hageböck, S; Hajduk, Z; Hakobyan, H; Haleem, M; Haley, J; Hall, D; Halladjian, G; Hallewell, G D; Hamacher, K; Hamal, P; Hamano, K; Hamer, M; Hamilton, A; Hamity, G N; Hamnett, P G; Han, L; Hanagaki, K; Hanawa, K; Hance, M; Hanke, P; Hanna, R; Hansen, J B; Hansen, J D; Hansen, M C; Hansen, P H; Hara, K; Hard, A S; Harenberg, T; Hariri, F; Harkusha, S; Harrington, R D; Harrison, P F; Hartjes, F; Hasegawa, M; Hasegawa, S; Hasegawa, Y; Hasib, A; Hassani, S; Haug, S; Hauser, R; Hauswald, L; Havranek, M; Hawkes, C M; Hawkings, R J; Hawkins, A D; Hayashi, T; Hayden, D; Hays, C P; Hays, J M; Hayward, H S; Haywood, S J; Head, S J; Heck, T; Hedberg, V; Heelan, L; Heim, S; Heim, T; Heinemann, B; Heinrich, L; Hejbal, J; Helary, L; Hellman, S; Hellmich, D; Helsens, C; Henderson, J; Henderson, R C W; Heng, Y; Hengler, C; Henrichs, A; Henriques Correia, A M; Henrot-Versille, S; Herbert, G H; Hernández Jiménez, Y; Herrberg-Schubert, R; Herten, G; Hertenberger, R; Hervas, L; Hesketh, G G; Hessey, N P; Hetherly, J W; Hickling, R; Higón-Rodriguez, E; Hill, E; Hill, J C; Hiller, K H; Hillier, S J; Hinchliffe, I; Hines, E; Hinman, R R; Hirose, M; Hirschbuehl, D; Hobbs, J; Hod, N; Hodgkinson, M C; Hodgson, P; Hoecker, A; Hoeferkamp, M R; Hoenig, F; Hohlfeld, M; Hohn, D; Holmes, T R; Homann, M; Hong, T M; Hooft van Huysduynen, L; Hopkins, W H; Horii, Y; Horton, A J; Hostachy, J-Y; Hou, S; Hoummada, A; Howard, J; Howarth, J; Hrabovsky, M; Hristova, I; Hrivnac, J; Hryn'ova, T; Hrynevich, A; Hsu, C; Hsu, P J; Hsu, S-C; Hu, D; Hu, Q; Hu, X; Huang, Y; Hubacek, Z; Hubaut, F; Huegging, F; Huffman, T B; Hughes, E W; Hughes, G; Huhtinen, M; Hülsing, T A; Huseynov, N; Huston, J; Huth, J; Iacobucci, G; Iakovidis, G; Ibragimov, I; Iconomidou-Fayard, L; Ideal, E; Idrissi, Z; Iengo, P; Igonkina, O; Iizawa, T; Ikegami, Y; Ikematsu, K; Ikeno, M; Ilchenko, Y; Iliadis, D; Ilic, N; Ince, T; Introzzi, G; Ioannou, P; Iodice, M; Iordanidou, K; Ippolito, V; Irles Quiles, A; Isaksson, C; Ishino, M; Ishitsuka, M; Ishmukhametov, R; Issever, C; Istin, S; Iturbe Ponce, J M; Iuppa, R; Ivarsson, J; Iwanski, W; Iwasaki, H; Izen, J M; Izzo, V; Jabbar, S; Jackson, B; Jackson, M; Jackson, P; Jaekel, M R; Jain, V; Jakobs, K; Jakobsen, S; Jakoubek, T; Jakubek, J; Jamin, D O; Jana, D K; Jansen, E; Jansky, R; Janssen, J; Janus, M; Jarlskog, G; Javadov, N; Javůrek, T; Jeanty, L; Jejelava, J; Jeng, G-Y; Jennens, D; Jenni, P; Jentzsch, J; Jeske, C; Jézéquel, S; Ji, H; Jia, J; Jiang, Y; Jiggins, S; Jimenez Pena, J; Jin, S; Jinaru, A; Jinnouchi, O; Joergensen, M D; Johansson, P; Johns, K A; Jon-And, K; Jones, G; Jones, R W L; Jones, T J; Jongmanns, J; Jorge, P M; Joshi, K D; Jovicevic, J; Ju, X; Jung, C A; Jussel, P; Juste Rozas, A; Kaci, M; Kaczmarska, A; Kado, M; Kagan, H; Kagan, M; Kahn, S J; Kajomovitz, E; Kalderon, C W; Kama, S; Kamenshchikov, A; Kanaya, N; Kaneti, S; Kantserov, V A; Kanzaki, J; Kaplan, B; Kaplan, L S; Kapliy, A; Kar, D; Karakostas, K; Karamaoun, A; Karastathis, N; Kareem, M J; Karnevskiy, M; Karpov, S N; Karpova, Z M; Karthik, K; Kartvelishvili, V; Karyukhin, A N; Kashif, L; Kass, R D; Kastanas, A; Kataoka, Y; Katre, A; Katzy, J; Kawagoe, K; Kawamoto, T; Kawamura, G; Kazama, S; Kazanin, V F; Kazarinov, M Y; Keeler, R; Kehoe, R; Keller, J S; Kempster, J J; Keoshkerian, H; Kepka, O; Kerševan, B P; Kersten, S; Keyes, R A; Khalil-Zada, F; Khandanyan, H; Khanov, A; Kharlamov, A G; Khoo, T J; Khovanskiy, V; Khramov, E; Khubua, J; Kim, H Y; Kim, H; Kim, S H; Kim, Y; Kimura, N; Kind, O M; King, B T; King, M; King, S B; Kirk, J; Kiryunin, A E; Kishimoto, T; Kisielewska, D; Kiss, F; Kiuchi, K; Kivernyk, O; Kladiva, E; Klein, M H; Klein, M; Klein, U; Kleinknecht, K; Klimek, P; Klimentov, A; Klingenberg, R; Klinger, J A; Klioutchnikova, T; Kluge, E-E; Kluit, P; Kluth, S; Knapik, J; Kneringer, E; Knoops, E B F G; Knue, A; Kobayashi, A; Kobayashi, D; Kobayashi, T; Kobel, M; Kocian, M; Kodys, P; Koffas, T; Koffeman, E; Kogan, L A; Kohlmann, S; Kohout, Z; Kohriki, T; Koi, T; Kolanoski, H; Koletsou, I; Komar, A A; Komori, Y; Kondo, T; Kondrashova, N; Köneke, K; König, A C; Kono, T; Konoplich, R; Konstantinidis, N; Kopeliansky, R; Koperny, S; Köpke, L; Kopp, A K; Korcyl, K; Kordas, K; Korn, A; Korol, A A; Korolkov, I; Korolkova, E V; Kortner, O; Kortner, S; Kosek, T; Kostyukhin, V V; Kotov, V M; Kotwal, A; Kourkoumeli-Charalampidi, A; Kourkoumelis, C; Kouskoura, V; Koutsman, A; Kowalewski, R; Kowalski, T Z; Kozanecki, W; Kozhin, A S; Kramarenko, V A; Kramberger, G; Krasnopevtsev, D; Krasny, M W; Krasznahorkay, A; Kraus, J K; Kravchenko, A; Kreiss, S; Kretz, M; Kretzschmar, J; Kreutzfeldt, K; Krieger, P; Krizka, K; Kroeninger, K; Kroha, H; Kroll, J; Kroseberg, J; Krstic, J; Kruchonak, U; Krüger, H; Krumnack, N; Krumshteyn, Z V; Kruse, A; Kruse, M C; Kruskal, M; Kubota, T; Kucuk, H; Kuday, S; Kuehn, S; Kugel, A; Kuger, F; Kuhl, A; Kuhl, T; Kukhtin, V; Kulchitsky, Y; Kuleshov, S; Kuna, M; Kunigo, T; Kupco, A; Kurashige, H; Kurochkin, Y A; Kus, V; Kuwertz, E S; Kuze, M; Kvita, J; Kwan, T; Kyriazopoulos, D; La Rosa, A; La Rosa Navarro, J L; La Rotonda, L; Lacasta, C; Lacava, F; Lacey, J; Lacker, H; Lacour, D; Lacuesta, V R; Ladygin, E; Lafaye, R; Laforge, B; Lagouri, T; Lai, S; Lambourne, L; Lammers, S; Lampen, C L; Lampl, W; Lançon, E; Landgraf, U; Landon, M P J; Lang, V S; Lange, J C; Lankford, A J; Lanni, F; Lantzsch, K; Lanza, A; Laplace, S; Lapoire, C; Laporte, J F; Lari, T; Lasagni Manghi, F; Lassnig, M; Laurelli, P; Lavrijsen, W; Law, A T; Laycock, P; Lazovich, T; Le Dortz, O; Le Guirriec, E; Le Menedeu, E; LeBlanc, M; LeCompte, T; Ledroit-Guillon, F; Lee, C A; Lee, S C; Lee, L; Lefebvre, G; Lefebvre, M; Legger, F; Leggett, C; Lehan, A; Lehmann Miotto, G; Lei, X; Leight, W A; Leisos, A; Leister, A G; Leite, M A L; Leitner, R; Lellouch, D; Lemmer, B; Leney, K J C; Lenz, T; Lenzi, B; Leone, R; Leone, S; Leonidopoulos, C; Leontsinis, S; Leroy, C; Lester, C G; Levchenko, M; Levêque, J; Levin, D; Levinson, L J; Levy, M; Lewis, A; Leyko, A M; Leyton, M; Li, B; Li, H; Li, H L; Li, L; Li, L; Li, S; Li, Y; Liang, Z; Liao, H; Liberti, B; Liblong, A; Lichard, P; Lie, K; Liebal, J; Liebig, W; Limbach, C; Limosani, A; Lin, S C; Lin, T H; Linde, F; Lindquist, B E; Linnemann, J T; Lipeles, E; Lipniacka, A; Lisovyi, M; Liss, T M; Lissauer, D; Lister, A; Litke, A M; Liu, B; Liu, D; Liu, H; Liu, J; Liu, J B; Liu, K; Liu, L; Liu, M; Liu, M; Liu, Y; Livan, M; Lleres, A; Llorente Merino, J; Lloyd, S L; Lo Sterzo, F; Lobodzinska, E; Loch, P; Lockman, W S; Loebinger, F K; Loevschall-Jensen, A E; Loginov, A; Lohse, T; Lohwasser, K; Lokajicek, M; Long, B A; Long, J D; Long, R E; Looper, K A; Lopes, L; Lopez Mateos, D; Lopez Paredes, B; Lopez Paz, I; Lorenz, J; Lorenzo Martinez, N; Losada, M; Loscutoff, P; Lösel, P J; Lou, X; Lounis, A; Love, J; Love, P A; Lu, N; Lubatti, H J; Luci, C; Lucotte, A; Luehring, F; Lukas, W; Luminari, L; Lundberg, O; Lund-Jensen, B; Lynn, D; Lysak, R; Lytken, E; Ma, H; Ma, L L; Maccarrone, G; Macchiolo, A; Macdonald, C M; Machado Miguens, J; Macina, D; Madaffari, D; Madar, R; Maddocks, H J; Mader, W F; Madsen, A; Maeland, S; Maeno, T; Maevskiy, A; Magradze, E; Mahboubi, K; Mahlstedt, J; Maiani, C; Maidantchik, C; Maier, A A; Maier, T; Maio, A; Majewski, S; Makida, Y; Makovec, N; Malaescu, B; Malecki, Pa; Maleev, V P; Malek, F; Mallik, U; Malon, D; Malone, C; Maltezos, S; Malyshev, V M; Malyukov, S; Mamuzic, J; Mancini, G; Mandelli, B; Mandelli, L; Mandić, I; Mandrysch, R; Maneira, J; Manfredini, A; Manhaes de Andrade Filho, L; Manjarres Ramos, J; Mann, A; Manning, P M; Manousakis-Katsikakis, A; Mansoulie, B; Mantifel, R; Mantoani, M; Mapelli, L; March, L; Marchiori, G; Marcisovsky, M; Marino, C P; Marjanovic, M; Marley, D E; Marroquim, F; Marsden, S P; Marshall, Z; Marti, L F; Marti-Garcia, S; Martin, B; Martin, T A; Martin, V J; Martin Dit Latour, B; Martinez, M; Martin-Haugh, S; Martoiu, V S; Martyniuk, A C; Marx, M; Marzano, F; Marzin, A; Masetti, L; Mashimo, T; Mashinistov, R; Masik, J; Maslennikov, A L; Massa, I; Massa, L; Massol, N; Mastrandrea, P; Mastroberardino, A; Masubuchi, T; Mättig, P; Mattmann, J; Maurer, J; Maxfield, S J; Maximov, D A; Mazini, R; Mazza, S M; Mazzaferro, L; Mc Goldrick, G; Mc Kee, S P; McCarn, A; McCarthy, R L; McCarthy, T G; McCubbin, N A; McFarlane, K W; Mcfayden, J A; Mchedlidze, G; McMahon, S J; McPherson, R A; Medinnis, M; Meehan, S; Mehlhase, S; Mehta, A; Meier, K; Meineck, C; Meirose, B; Mellado Garcia, B R; Meloni, F; Mengarelli, A; Menke, S; Meoni, E; Mercurio, K M; Mergelmeyer, S; Mermod, P; Merola, L; Meroni, C; Merritt, F S; Messina, A; Metcalfe, J; Mete, A S; Meyer, C; Meyer, C; Meyer, J-P; Meyer, J; Middleton, R P; Miglioranzi, S; Mijović, L; Mikenberg, G; Mikestikova, M; Mikuž, M; Milesi, M; Milic, A; Miller, D W; Mills, C; Milov, A; Milstead, D A; Minaenko, A A; Minami, Y; Minashvili, I A; Mincer, A I; Mindur, B; Mineev, M; Ming, Y; Mir, L M; Mitani, T; Mitrevski, J; Mitsou, V A; Miucci, A; Miyagawa, P S; Mjörnmark, J U; Moa, T; Mochizuki, K; Mohapatra, S; Mohr, W; Molander, S; Moles-Valls, R; Mönig, K; Monini, C; Monk, J; Monnier, E; Montejo Berlingen, J; Monticelli, F; Monzani, S; Moore, R W; Morange, N; Moreno, D; Moreno Llácer, M; Morettini, P; Morgenstern, M; Morii, M; Morinaga, M; Morisbak, V; Moritz, S; Morley, A K; Mornacchi, G; Morris, J D; Mortensen, S S; Morton, A; Morvaj, L; Mosidze, M; Moss, J; Motohashi, K; Mount, R; Mountricha, E; Mouraviev, S V; Moyse, E J W; Muanza, S; Mudd, R D; Mueller, F; Mueller, J; Mueller, R S P; Mueller, T; Muenstermann, D; Mullen, P; Mullier, G A; Murillo Quijada, J A; Murray, W J; Musheghyan, H; Musto, E; Myagkov, A G; Myska, M; Nackenhorst, O; Nadal, J; Nagai, K; Nagai, R; Nagai, Y; Nagano, K; Nagarkar, A; Nagasaka, Y; Nagata, K; Nagel, M; Nagy, E; Nairz, A M; Nakahama, Y; Nakamura, K; Nakamura, T; Nakano, I; Namasivayam, H; Naranjo Garcia, R F; Narayan, R; Naumann, T; Navarro, G; Nayyar, R; Neal, H A; Nechaeva, P Yu; Neep, T J; Nef, P D; Negri, A; Negrini, M; Nektarijevic, S; Nellist, C; Nelson, A; Nemecek, S; Nemethy, P; Nepomuceno, A A; Nessi, M; Neubauer, M S; Neumann, M; Neves, R M; Nevski, P; Newman, P R; Nguyen, D H; Nickerson, R B; Nicolaidou, R; Nicquevert, B; Nielsen, J; Nikiforou, N; Nikiforov, A; Nikolaenko, V; Nikolic-Audit, I; Nikolopoulos, K; Nilsen, J K; Nilsson, P; Ninomiya, Y; Nisati, A; Nisius, R; Nobe, T; Nomachi, M; Nomidis, I; Nooney, T; Norberg, S; Nordberg, M; Novgorodova, O; Nowak, S; Nozaki, M; Nozka, L; Ntekas, K; Nunes Hanninger, G; Nunnemann, T; Nurse, E; Nuti, F; O'Brien, B J; O'grady, F; O'Neil, D C; O'Shea, V; Oakham, F G; Oberlack, H; Obermann, T; Ocariz, J; Ochi, A; Ochoa, I; Ochoa-Ricoux, J P; Oda, S; Odaka, S; Ogren, H; Oh, A; Oh, S H; Ohm, C C; Ohman, H; Oide, H; Okamura, W; Okawa, H; Okumura, Y; Okuyama, T; Olariu, A; Olivares Pino, S A; Oliveira Damazio, D; Oliver Garcia, E; Olszewski, A; Olszowska, J; Onofre, A; Onyisi, P U E; Oram, C J; Oreglia, M J; Oren, Y; Orestano, D; Orlando, N; Oropeza Barrera, C; Orr, R S; Osculati, B; Ospanov, R; Otero Y Garzon, G; Otono, H; Ouchrif, M; Ouellette, E A; Ould-Saada, F; Ouraou, A; Oussoren, K P; Ouyang, Q; Ovcharova, A; Owen, M; Owen, R E; Ozcan, V E; Ozturk, N; Pachal, K; Pacheco Pages, A; Padilla Aranda, C; Pagáčová, M; Pagan Griso, S; Paganis, E; Paige, F; Pais, P; Pajchel, K; Palacino, G; Palestini, S; Palka, M; Pallin, D; Palma, A; Pan, Y B; Panagiotopoulou, E; Pandini, C E; Panduro Vazquez, J G; Pani, P; Panitkin, S; Pantea, D; Paolozzi, L; Papadopoulou, Th D; Papageorgiou, K; Paramonov, A; Paredes Hernandez, D; Parker, M A; Parker, K A; Parodi, F; Parsons, J A; Parzefall, U; Pasqualucci, E; Passaggio, S; Pastore, F; Pastore, Fr; Pásztor, G; Pataraia, S; Patel, N D; Pater, J R; Pauly, T; Pearce, J; Pearson, B; Pedersen, L E; Pedersen, M; Pedraza Lopez, S; Pedro, R; Peleganchuk, S V; Pelikan, D; Penc, O; Peng, C; Peng, H; Penning, B; Penwell, J; Perepelitsa, D V; Perez Codina, E; Pérez García-Estañ, M T; Perini, L; Pernegger, H; Perrella, S; Peschke, R; Peshekhonov, V D; Peters, K; Peters, R F Y; Petersen, B A; Petersen, T C; Petit, E; Petridis, A; Petridou, C; Petrolo, E; Petrucci, F; Pettersson, N E; Pezoa, R; Phillips, P W; Piacquadio, G; Pianori, E; Picazio, A; Piccaro, E; Piccinini, M; Pickering, M A; Piegaia, R; Pignotti, D T; Pilcher, J E; Pilkington, A D; Pina, J; Pinamonti, M; Pinfold, J L; Pingel, A; Pinto, B; Pires, S; Pirumov, H; Pitt, M; Pizio, C; Plazak, L; Pleier, M-A; Pleskot, V; Plotnikova, E; Plucinski, P; Pluth, D; Poettgen, R; Poggioli, L; Pohl, D; Polesello, G; Poley, A; Policicchio, A; Polifka, R; Polini, A; Pollard, C S; Polychronakos, V; Pommès, K; Pontecorvo, L; Pope, B G; Popeneciu, G A; Popovic, D S; Poppleton, A; Pospisil, S; Potamianos, K; Potrap, I N; Potter, C J; Potter, C T; Poulard, G; Poveda, J; Pozdnyakov, V; Pralavorio, P; Pranko, A; Prasad, S; Prell, S; Price, D; Price, L E; Primavera, M; Prince, S; Proissl, M; Prokofiev, K; Prokoshin, F; Protopapadaki, E; Protopopescu, S; Proudfoot, J; Przybycien, M; Ptacek, E; Puddu, D; Pueschel, E; Puldon, D; Purohit, M; Puzo, P; Qian, J; Qin, G; Qin, Y; Quadt, A; Quarrie, D R; Quayle, W B; Queitsch-Maitland, M; Quilty, D; Raddum, S; Radeka, V; Radescu, V; Radhakrishnan, S K; Radloff, P; Rados, P; Ragusa, F; Rahal, G; Rajagopalan, S; Rammensee, M; Rangel-Smith, C; Rauscher, F; Rave, S; Ravenscroft, T; Raymond, M; Read, A L; Readioff, N P; Rebuzzi, D M; Redelbach, A; Redlinger, G; Reece, R; Reeves, K; Rehnisch, L; Reisin, H; Relich, M; Rembser, C; Ren, H; Renaud, A; Rescigno, M; Resconi, S; Rezanova, O L; Reznicek, P; Rezvani, R; Richter, R; Richter, S; Richter-Was, E; Ricken, O; Ridel, M; Rieck, P; Riegel, C J; Rieger, J; Rijssenbeek, M; Rimoldi, A; Rinaldi, L; Ristić, B; Ritsch, E; Riu, I; Rizatdinova, F; Rizvi, E; Robertson, S H; Robichaud-Veronneau, A; Robinson, D; Robinson, J E M; Robson, A; Roda, C; Roe, S; Røhne, O; Rolli, S; Romaniouk, A; Romano, M; Romano Saez, S M; Romero Adam, E; Rompotis, N; Ronzani, M; Roos, L; Ros, E; Rosati, S; Rosbach, K; Rose, P; Rosendahl, P L; Rosenthal, O; Rossetti, V; Rossi, E; Rossi, L P; Rosten, R; Rotaru, M; Roth, I; Rothberg, J; Rousseau, D; Royon, C R; Rozanov, A; Rozen, Y; Ruan, X; Rubbo, F; Rubinskiy, I; Rud, V I; Rudolph, C; Rudolph, M S; Rühr, F; Ruiz-Martinez, A; Rurikova, Z; Rusakovich, N A; Ruschke, A; Russell, H L; Rutherfoord, J P; Ruthmann, N; Ryabov, Y F; Rybar, M; Rybkin, G; Ryder, N C; Saavedra, A F; Sabato, G; Sacerdoti, S; Saddique, A; Sadrozinski, H F-W; Sadykov, R; Safai Tehrani, F; Saimpert, M; Sakamoto, H; Sakurai, Y; Salamanna, G; Salamon, A; Saleem, M; Salek, D; Sales De Bruin, P H; Salihagic, D; Salnikov, A; Salt, J; Salvatore, D; Salvatore, F; Salvucci, A; Salzburger, A; Sampsonidis, D; Sanchez, A; Sánchez, J; Sanchez Martinez, V; Sandaker, H; Sandbach, R L; Sander, H G; Sanders, M P; Sandhoff, M; Sandoval, C; Sandstroem, R; Sankey, D P C; Sannino, M; Sansoni, A; Santoni, C; Santonico, R; Santos, H; Santoyo Castillo, I; Sapp, K; Sapronov, A; Saraiva, J G; Sarrazin, B; Sasaki, O; Sasaki, Y; Sato, K; Sauvage, G; Sauvan, E; Savage, G; Savard, P; Sawyer, C; Sawyer, L; Saxon, J; Sbarra, C; Sbrizzi, A; Scanlon, T; Scannicchio, D A; Scarcella, M; Scarfone, V; Schaarschmidt, J; Schacht, P; Schaefer, D; Schaefer, R; Schaeffer, J; Schaepe, S; Schaetzel, S; Schäfer, U; Schaffer, A C; Schaile, D; Schamberger, R D; Scharf, V; Schegelsky, V A; Scheirich, D; Schernau, M; Schiavi, C; Schillo, C; Schioppa, M; Schlenker, S; Schmidt, E; Schmieden, K; Schmitt, C; Schmitt, S; Schmitt, S; Schneider, B; Schnellbach, Y J; Schnoor, U; Schoeffel, L; Schoening, A; Schoenrock, B D; Schopf, E; Schorlemmer, A L S; Schott, M; Schouten, D; Schovancova, J; Schramm, S; Schreyer, M; Schroeder, C; Schuh, N; Schultens, M J; Schultz-Coulon, H-C; Schulz, H; Schumacher, M; Schumm, B A; Schune, Ph; Schwanenberger, C; Schwartzman, A; Schwarz, T A; Schwegler, Ph; Schweiger, H; Schwemling, Ph; Schwienhorst, R; Schwindling, J; Schwindt, T; Sciacca, F G; Scifo, E; Sciolla, G; Scuri, F; Scutti, F; Searcy, J; Sedov, G; Sedykh, E; Seema, P; Seidel, S C; Seiden, A; Seifert, F; Seixas, J M; Sekhniaidze, G; Sekhon, K; Sekula, S J; Seliverstov, D M; Semprini-Cesari, N; Serfon, C; Serin, L; Serkin, L; Serre, T; Sessa, M; Seuster, R; Severini, H; Sfiligoj, T; Sforza, F; Sfyrla, A; Shabalina, E; Shamim, M; Shan, L Y; Shang, R; Shank, J T; Shapiro, M; Shatalov, P B; Shaw, K; Shaw, S M; Shcherbakova, A; Shehu, C Y; Sherwood, P; Shi, L; Shimizu, S; Shimmin, C O; Shimojima, M; Shiyakova, M; Shmeleva, A; Shoaleh Saadi, D; Shochet, M J; Shojaii, S; Shrestha, S; Shulga, E; Shupe, M A; Shushkevich, S; Sicho, P; Sidebo, P E; Sidiropoulou, O; Sidorov, D; Sidoti, A; Siegert, F; Sijacki, Dj; Silva, J; Silver, Y; Silverstein, S B; Simak, V; Simard, O; Simic, Lj; Simion, S; Simioni, E; Simmons, B; Simon, D; Simoniello, R; Sinervo, P; Sinev, N B; Sioli, M; Siragusa, G; Sisakyan, A N; Sivoklokov, S Yu; Sjölin, J; Sjursen, T B; Skinner, M B; Skottowe, H P; Skubic, P; Slater, M; Slavicek, T; Slawinska, M; Sliwa, K; Smakhtin, V; Smart, B H; Smestad, L; Smirnov, S Yu; Smirnov, Y; Smirnova, L N; Smirnova, O; Smith, M N K; Smith, R W; Smizanska, M; Smolek, K; Snesarev, A A; Snidero, G; Snyder, S; Sobie, R; Socher, F; Soffer, A; Soh, D A; Solans, C A; Solar, M; Solc, J; Soldatov, E Yu; Soldevila, U; Solodkov, A A; Soloshenko, A; Solovyanov, O V; Solovyev, V; Sommer, P; Song, H Y; Soni, N; Sood, A; Sopczak, A; Sopko, B; Sopko, V; Sorin, V; Sosa, D; Sosebee, M; Sotiropoulou, C L; Soualah, R; Soukharev, A M; South, D; Sowden, B C; Spagnolo, S; Spalla, M; Spanò, F; Spearman, W R; Sperlich, D; Spettel, F; Spighi, R; Spigo, G; Spiller, L A; Spousta, M; Spreitzer, T; St Denis, R D; Staerz, S; Stahlman, J; Stamen, R; Stamm, S; Stanecka, E; Stanescu, C; Stanescu-Bellu, M; Stanitzki, M M; Stapnes, S; Starchenko, E A; Stark, J; Staroba, P; Starovoitov, P; Staszewski, R; Stavina, P; Steinberg, P; Stelzer, B; Stelzer, H J; Stelzer-Chilton, O; Stenzel, H; Stewart, G A; Stillings, J A; Stockton, M C; Stoebe, M; Stoicea, G; Stolte, P; Stonjek, S; Stradling, A R; Straessner, A; Stramaglia, M E; Strandberg, J; Strandberg, S; Strandlie, A; Strauss, E; Strauss, M; Strizenec, P; Ströhmer, R; Strom, D M; Stroynowski, R; Strubig, A; Stucci, S A; Stugu, B; Styles, N A; Su, D; Su, J; Subramaniam, R; Succurro, A; Sugaya, Y; Suhr, C; Suk, M; Sulin, V V; Sultansoy, S; Sumida, T; Sun, S; Sun, X; Sundermann, J E; Suruliz, K; Susinno, G; Sutton, M R; Suzuki, S; Svatos, M; Swedish, S; Swiatlowski, M; Sykora, I; Sykora, T; Ta, D; Taccini, C; Tackmann, K; Taenzer, J; Taffard, A; Tafirout, R; Taiblum, N; Takai, H; Takashima, R; Takeda, H; Takeshita, T; Takubo, Y; Talby, M; Talyshev, A A; Tam, J Y C; Tan, K G; Tanaka, J; Tanaka, R; Tanaka, S; Tannenwald, B B; Tannoury, N; Tapprogge, S; Tarem, S; Tarrade, F; Tartarelli, G F; Tas, P; Tasevsky, M; Tashiro, T; Tassi, E; Tavares Delgado, A; Tayalati, Y; Taylor, F E; Taylor, G N; Taylor, W; Teischinger, F A; Teixeira Dias Castanheira, M; Teixeira-Dias, P; Temming, K K; Ten Kate, H; Teng, P K; Teoh, J J; Tepel, F; Terada, S; Terashi, K; Terron, J; Terzo, S; Testa, M; Teuscher, R J; Theveneaux-Pelzer, T; Thomas, J P; Thomas-Wilsker, J; Thompson, E N; Thompson, P D; Thompson, R J; Thompson, A S; Thomsen, L A; Thomson, E; Thomson, M; Thun, R P; Tibbetts, M J; Ticse Torres, R E; Tikhomirov, V O; Tikhonov, Yu A; Timoshenko, S; Tiouchichine, E; Tipton, P; Tisserant, S; Todome, K; Todorov, T; Todorova-Nova, S; Tojo, J; Tokár, S; Tokushuku, K; Tollefson, K; Tolley, E; Tomlinson, L; Tomoto, M; Tompkins, L; Toms, K; Torrence, E; Torres, H; Torró Pastor, E; Toth, J; Touchard, F; Tovey, D R; Trefzger, T; Tremblet, L; Tricoli, A; Trigger, I M; Trincaz-Duvoid, S; Tripiana, M F; Trischuk, W; Trocmé, B; Troncon, C; Trottier-McDonald, M; Trovatelli, M; True, P; Truong, L; Trzebinski, M; Trzupek, A; Tsarouchas, C; Tseng, J C-L; Tsiareshka, P V; Tsionou, D; Tsipolitis, G; Tsirintanis, N; Tsiskaridze, S; Tsiskaridze, V; Tskhadadze, E G; Tsukerman, I I; Tsulaia, V; Tsuno, S; Tsybychev, D; Tudorache, A; Tudorache, V; Tuna, A N; Tupputi, S A; Turchikhin, S; Turecek, D; Turra, R; Turvey, A J; Tuts, P M; Tykhonov, A; Tylmad, M; Tyndel, M; Ueda, I; Ueno, R; Ughetto, M; Ugland, M; Uhlenbrock, M; Ukegawa, F; Unal, G; Undrus, A; Unel, G; Ungaro, F C; Unno, Y; Unverdorben, C; Urban, J; Urquijo, P; Urrejola, P; Usai, G; Usanova, A; Vacavant, L; Vacek, V; Vachon, B; Valderanis, C; Valencic, N; Valentinetti, S; Valero, A; Valery, L; Valkar, S; Valladolid Gallego, E; Vallecorsa, S; Valls Ferrer, J A; Van Den Wollenberg, W; Van Der Deijl, P C; van der Geer, R; van der Graaf, H; Van Der Leeuw, R; van Eldik, N; van Gemmeren, P; Van Nieuwkoop, J; van Vulpen, I; van Woerden, M C; Vanadia, M; Vandelli, W; Vanguri, R; Vaniachine, A; Vannucci, F; Vardanyan, G; Vari, R; Varnes, E W; Varol, T; Varouchas, D; Vartapetian, A; Varvell, K E; Vazeille, F; Vazquez Schroeder, T; Veatch, J; Veloce, L M; Veloso, F; Velz, T; Veneziano, S; Ventura, A; Ventura, D; Venturi, M; Venturi, N; Venturini, A; Vercesi, V; Verducci, M; Verkerke, W; Vermeulen, J C; Vest, A; Vetterli, M C; Viazlo, O; Vichou, I; Vickey, T; Vickey Boeriu, O E; Viehhauser, G H A; Viel, S; Vigne, R; Villa, M; Villaplana Perez, M; Vilucchi, E; Vincter, M G; Vinogradov, V B; Vivarelli, I; Vives Vaque, F; Vlachos, S; Vladoiu, D; Vlasak, M; Vogel, M; Vokac, P; Volpi, G; Volpi, M; von der Schmitt, H; von Radziewski, H; von Toerne, E; Vorobel, V; Vorobev, K; Vos, M; Voss, R; Vossebeld, J H; Vranjes, N; Vranjes Milosavljevic, M; Vrba, V; Vreeswijk, M; Vuillermet, R; Vukotic, I; Vykydal, Z; Wagner, P; Wagner, W; Wahlberg, H; Wahrmund, S; Wakabayashi, J; Walder, J; Walker, R; Walkowiak, W; Wang, C; Wang, F; Wang, H; Wang, H; Wang, J; Wang, J; Wang, K; Wang, R; Wang, S M; Wang, T; Wang, T; Wang, X; Wanotayaroj, C; Warburton, A; Ward, C P; Wardrope, D R; Warsinsky, M; Washbrook, A; Wasicki, C; Watkins, P M; Watson, A T; Watson, I J; Watson, M F; Watts, G; Watts, S; Waugh, B M; Webb, S; Weber, M S; Weber, S W; Webster, J S; Weidberg, A R; Weinert, B; Weingarten, J; Weiser, C; Weits, H; Wells, P S; Wenaus, T; Wengler, T; Wenig, S; Wermes, N; Werner, M; Werner, P; Wessels, M; Wetter, J; Whalen, K; Wharton, A M; White, A; White, M J; White, R; White, S; Whiteson, D; Wickens, F J; Wiedenmann, W; Wielers, M; Wienemann, P; Wiglesworth, C; Wiik-Fuchs, L A M; Wildauer, A; Wilkens, H G; Williams, H H; Williams, S; Willis, C; Willocq, S; Wilson, A; Wilson, J A; Wingerter-Seez, I; Winklmeier, F; Winter, B T; Wittgen, M; Wittkowski, J; Wollstadt, S J; Wolter, M W; Wolters, H; Wosiek, B K; Wotschack, J; Woudstra, M J; Wozniak, K W; Wu, M; Wu, M; Wu, S L; Wu, X; Wu, Y; Wyatt, T R; Wynne, B M; Xella, S; Xu, D; Xu, L; Yabsley, B; Yacoob, S; Yakabe, R; Yamada, M; Yamaguchi, Y; Yamamoto, A; Yamamoto, S; Yamanaka, T; Yamauchi, K; Yamazaki, Y; Yan, Z; Yang, H; Yang, H; Yang, Y; Yao, W-M; Yasu, Y; Yatsenko, E; Yau Wong, K H; Ye, J; Ye, S; Yeletskikh, I; Yen, A L; Yildirim, E; Yorita, K; Yoshida, R; Yoshihara, K; Young, C; Young, C J S; Youssef, S; Yu, D R; Yu, J; Yu, J M; Yu, J; Yuan, L; Yurkewicz, A; Yusuff, I; Zabinski, B; Zaidan, R; Zaitsev, A M; Zalieckas, J; Zaman, A; Zambito, S; Zanello, L; Zanzi, D; Zeitnitz, C; Zeman, M; Zemla, A; Zengel, K; Zenin, O; Ženiš, T; Zerwas, D; Zhang, D; Zhang, F; Zhang, H; Zhang, J; Zhang, L; Zhang, R; Zhang, X; Zhang, Z; Zhao, X; Zhao, Y; Zhao, Z; Zhemchugov, A; Zhong, J; Zhou, B; Zhou, C; Zhou, L; Zhou, L; Zhou, N; Zhu, C G; Zhu, H; Zhu, J; Zhu, Y; Zhuang, X; Zhukov, K; Zibell, A; Zieminska, D; Zimine, N I; Zimmermann, C; Zimmermann, S; Zinonos, Z; Zinser, M; Ziolkowski, M; Živković, L; Zobernig, G; Zoccoli, A; Zur Nedden, M; Zurzolo, G; Zwalinski, L
Studies of the spin, parity and tensor couplings of the Higgs boson in the [Formula: see text], [Formula: see text] and [Formula: see text] decay processes at the LHC are presented. The investigations are based on [Formula: see text] of pp collision data collected by the ATLAS experiment at [Formula: see text] TeV and [Formula: see text] TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers [Formula: see text], is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at more than 99.9 % confidence level. Using the [Formula: see text] and [Formula: see text] decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. The observed distributions of variables sensitive to the non-SM tensor couplings are compatible with the SM predictions and constraints on the non-SM couplings are derived.
Search for Third Generation Squarks in the Missing Transverse Energy plus Jet Sample at CDF Run II
DOE Office of Scientific and Technical Information (OSTI.GOV)
Marono, Miguel Vidal
The twentieth century leaves behind one of the most impressive legacies, in terms of human knowledge, ever achieved. In particular the StandardModel (SM) of particle physics has proven to be one of the most accurate descriptions of Nature. The level of accuracy of some theoretical predictions has never been attained before. It includes the electromagnetic interaction, and the weak and strong force, developing the Lagrangian from symmetry principles. There are two different types of fundamental constituents of Nature, in the framework of the Standard Model: bosons and fermions. Bosons are those particles responsible for carrying the interactions among the fermions, which constitute matter. Fermions are divide into six quarks and six leptons, forming a three-folded structure. All these fermions and bosons have an antimatter partner. However, several difficulties point along with the idea that the Standard Model is only an effective low energy theory. These limitations include the difficulty to incorporate gravity and the lack of justification to fine tuning of some perturbative corrections. Moreover, some regions of the theory are not understood, like the mass spectrum of the Standard Model or the mechanism for electroweak symmetry breaking. Supersymmetry is a newer theoretical framework, thought to adress the problems found in the Standard Model, while preserving all its predictive power. It introduces a new symmetry that relates a new boson to each SM fermion and a new fermion to each SM boson. In this way, for every existing boson in the SM it must exist a fermionic super-partner (named with a sufix ino), and likewise, for every fermion a bosonic super-partner (named with a prefix s) must also exist. Moreover, another symmetry called R-parity is introduced to prevent baryon and lepton number violating interactions. If R-parity is conserved, super-particles can only be pair-produced and they cannot decay completely in SM particles. This implies the existence of a lightest SUSY particle (LSP) which would provide a candidate for cold dark matter, that account for 23% of the universe content, as strongly suggested by recent astrophysical data [1]. The Tevatron is a hadron collider operating at Fermilab, USA. This accelerator provides proton-antiproton (pmore » $$\\bar{p}$$) collisions with a center of mass energy of √s = 1.96 TeV. CDF and D0 are the detectors built to analyse the products of the collisions provided by the Tevatron. Both experiments have produced a very significant scientific output in the last few years, like the discovery of the top quark or the measurement of the B s mixing. The Tevatron experiments are also reaching sensitivity to the SM Higgs boson. The scientific program of CDF includes a broad spectrum on searches for physics signatures beyond the Standard Model. Tevatron is still the energy frontier, what means an unique opportunity to produce a discovery in physic beyond the Standard Model. The analyses presented in this thesis focus on the search for third generation squarks in the missing transverse energy plus jets final state. The production of sbottom ($$\\tilde{b}$$) and stop ($$\\tilde{t}$$) quarks could be highly enhanced at the Tevatron, giving the possibility of discovering new physics or limiting the parameter space available in the theory. No signal is found over the predicted Standard Model background in both searches. Instead, 95% confidence level limits are set on the production cross section, and then translated into the mass plane of the hypothetical particles. This thesis sketches the basic theory concepts of the Standard Model and the Minimal Supersymmetric Extension in Chapter 2. Chapter 3, describes the Tevatron and CDF. Based on the CDF subsystems information, Chapter 4 and 5 describe the analysis objet reconstruction and the heavy flavor tagging tools. The development of the analyses is shown in Chapter 6 and Chapter 7. Finally, Chapter 8 is devoted to discuss the results and conclusions of this work, and future prospects.« less
The Emergence of Fermions and the E11 Content
NASA Astrophysics Data System (ADS)
Englert, François; Houart, Laurent
Claudio's warm and endearing personality adds to our admiration for his achievements in physics a sense of friendliness. His constant interest in fundamental questions motivated the following presentation of our attempt to understand the nature of fermions. This problem is an essential element of the quantum world and might be related to the quest for quantum gravity. We shall review how space-time fermions can emerge out of bosons in string theory and how this fact affects the extended Kac-Moody approach to the M-theory project.
Multiple Types of Topological Fermions in Transition Metal Silicides
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tang, Peizhe; Zhou, Quan; Zhang, Shou -Cheng
Exotic massless fermionic excitations with nonzero Berry flux, other than the Dirac and Weyl fermions, could exist in condensed matter systems under the protection of crystalline symmetries, such as spin-1 excitations with threefold degeneracy and spin-3/2 Rarita-Schwinger-Weyl fermions. Herein, by using the ab initio density functional theory, we show that these unconventional quasiparticles coexist with type-I and type-II Weyl fermions in a family of transition metal silicides, including CoSi, RhSi, RhGe, and CoGe, when spin-orbit coupling is considered. Their nontrivial topology results in a series of extensive Fermi arcs connecting projections of these bulk excitations on the side surface, whichmore » is confirmed by (001) surface electronic spectra of CoSi. Additionally, these stable arc states exist within a wide energy window around the Fermi level, which makes them readily accessible in angle-resolved photoemission spectroscopy measurements.« less
Multiple Types of Topological Fermions in Transition Metal Silicides
Tang, Peizhe; Zhou, Quan; Zhang, Shou -Cheng
2017-11-17
Exotic massless fermionic excitations with nonzero Berry flux, other than the Dirac and Weyl fermions, could exist in condensed matter systems under the protection of crystalline symmetries, such as spin-1 excitations with threefold degeneracy and spin-3/2 Rarita-Schwinger-Weyl fermions. Herein, by using the ab initio density functional theory, we show that these unconventional quasiparticles coexist with type-I and type-II Weyl fermions in a family of transition metal silicides, including CoSi, RhSi, RhGe, and CoGe, when spin-orbit coupling is considered. Their nontrivial topology results in a series of extensive Fermi arcs connecting projections of these bulk excitations on the side surface, whichmore » is confirmed by (001) surface electronic spectra of CoSi. Additionally, these stable arc states exist within a wide energy window around the Fermi level, which makes them readily accessible in angle-resolved photoemission spectroscopy measurements.« less
Higgs boson studies at the tevatron
Herner, Kenneth
2016-05-31
We present the combination of searches for the Standard Model Higgs boson at a center-of-mass energy of √s = 1.96 TeV , using the full Run 2 dataset collected with the CDF and D0 detectors at the Fermilab Tevatron collider. We also present combined measurements of Higgs Boson production cross sections, branching ratios, and couplings to fermions and bosons. Lastly, we present tests of different spin and parity hypotheses for a particle H of mass 125 GeV produced in association with a vector boson and decaying into a pair of b quarks, and place constraints on such hypotheses using the D0more » data.« less
NASA Astrophysics Data System (ADS)
Wang, Hai-Xiao; Chen, Yige; Hang, Zhi Hong; Kee, Hae-Young; Jiang, Jian-Hua
2017-09-01
The Dirac equation for relativistic electron waves is the parent model for Weyl and Majorana fermions as well as topological insulators. Simulation of Dirac physics in three-dimensional photonic crystals, though fundamentally important for topological phenomena at optical frequencies, encounters the challenge of synthesis of both Kramers double degeneracy and parity inversion. Here we show how type-II Dirac points—exotic Dirac relativistic waves yet to be discovered—are robustly realized through the nonsymmorphic screw symmetry. The emergent type-II Dirac points carry nontrivial topology and are the mother states of type-II Weyl points. The proposed all-dielectric architecture enables robust cavity states at photonic-crystal—air interfaces and anomalous refraction, with very low energy dissipation.
77 FR 63923 - Proposed Collection; Comment Request for Regulation Project
Federal Register 2010, 2011, 2012, 2013, 2014
2012-10-17
... Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008, which requires parity... forms of information technology; and (e) estimates of capital or start-up costs and costs of operation...
NASA Astrophysics Data System (ADS)
Zhang, Yi; Vishwanath, Ashvin
2013-04-01
We use entanglement entropy signatures to establish non-Abelian topological order in projected Chern-insulator wave functions. The simplest instance is obtained by Gutzwiller projecting a filled band with Chern number C=2, whose wave function may also be viewed as the square of the Slater determinant of a band insulator. We demonstrate that this wave function is captured by the SU(2)2 Chern-Simons theory coupled to fermions. This is established most persuasively by calculating the modular S-matrix from the candidate ground-state wave functions, following a recent entanglement-entropy-based approach. This directly demonstrates the peculiar non-Abelian braiding statistics of Majorana fermion quasiparticles in this state. We also provide microscopic evidence for the field theoretic generalization, that the Nth power of a Chern number C Slater determinant realizes the topological order of the SU(N)C Chern-Simons theory coupled to fermions, by studying the SU(2)3 (Read-Rezayi-type state) and the SU(3)2 wave functions. An advantage of our projected Chern-insulator wave functions is the relative ease with which physical properties, such as entanglement entropy and modular S-matrix, can be numerically calculated using Monte Carlo techniques.
Quark seesaw mechanism, dark U (1 ) symmetry, and the baryon-dark matter coincidence
NASA Astrophysics Data System (ADS)
Gu, Pei-Hong; Mohapatra, Rabindra N.
2017-09-01
We attempt to understand the baryon-dark matter coincidence problem within the quark seesaw extension of the standard model where parity invariance is used to solve the strong C P problem. The S U (2 )L×S U (2 )R×U (1 )B -L gauge symmetry of this model is extended by a dark U (1 )X group plus inclusion of a heavy neutral vector-like fermion χL ,R charged under the dark group which plays the role of dark matter. All fermions are Dirac type in this model. Decay of heavy scalars charged under U (1 )X leads to simultaneous asymmetry generation of the dark matter and baryons after sphaleron effects are included. The U (1 )X group not only helps to stabilize the dark matter but also helps in the elimination of the symmetric part of the dark matter via χ -χ ¯ annihilation. For dark matter mass near the proton mass, it explains why the baryon and dark matter abundances are of similar magnitude (the baryon-dark matter coincidence problem). This model is testable in low threshold (sub-keV) direct dark matter search experiments.
NASA Astrophysics Data System (ADS)
Xiang-Guo, Meng; Ji-Suo, Wang; Hong-Yi, Fan; Cheng-Wei, Xia
2016-04-01
We solve the fermionic master equation for a thermal bath to obtain its explicit Kraus operator solutions via the fermionic state approach. The normalization condition of the Kraus operators is proved. The matrix representation for these solutions is obtained, which is incongruous with the result in the book completed by Nielsen and Chuang [Quantum Computation and Quantum Information, Cambridge University Press, 2000]. As especial cases, we also present the Kraus operator solutions to master equations for describing the amplitude-decay model and the diffusion process at finite temperature. Project supported by the National Natural Science Foundation of China (Grant No. 11347026), the Natural Science Foundation of Shandong Province, China (Grant Nos. ZR2013AM012 and ZR2012AM004), and the Research Fund for the Doctoral Program and Scientific Research Project of Liaocheng University, Shandong Province, China.
NASA Astrophysics Data System (ADS)
Wang, Juven; Ohmori, Kantaro; Putrov, Pavel; Zheng, Yunqin; Wan, Zheyan; Guo, Meng; Lin, Hai; Gao, Peng; Yau, Shing-Tung
2018-05-01
Distinct quantum vacua of topologically ordered states can be tunneled into each other via extended operators. The possible applications include condensed matter and quantum cosmology. We present a straightforward approach to calculate the partition function on various manifolds and ground state degeneracy (GSD), mainly based on continuum/cochain topological quantum field theories (TQFTs), in any dimension. This information can be related to the counting of extended operators of bosonic/fermionic TQFTs. On the lattice scale, anyonic particles/strings live at the ends of line/surface operators. Certain systems in different dimensions are related to each other through dimensional reduction schemes, analogous to (de)categorification. Examples include spin TQFTs derived from gauging the interacting fermionic symmetry-protected topological states (with fermion parity {Z}_2^f) of symmetry groups {Z}_4× {Z}_2 and ({Z}_4)^2 in 3+1D, also {Z}_2 and ({Z}_2)^2 in 2+1D. Gauging the last three cases begets non-Abelian spin TQFTs (fermionic topological order). We consider situations where a TQFT lives on (1) a closed spacetime or (2) a spacetime with a boundary, such that the bulk and boundary are fully gapped and short- or long-range entangled (SRE/LRE). Anyonic excitations can be deconfined on the boundary. We introduce new exotic topological interfaces on which neither particle nor string excitations alone condense, but only fuzzy-composite objects of extended operators can end (e.g., a string-like composite object formed by a set of particles can end on a special 2+1D boundary of 3+1D bulk). We explore the relations between group extension constructions and partially breaking constructions (e.g., 0-form/higher-form/"composite" breaking) of topological boundaries, after gauging. We comment on the implications of entanglement entropy for some such LRE systems.
Odd-even parity splittings and octupole correlations in neutron-rich Ba isotopes
NASA Astrophysics Data System (ADS)
Fu, Y.; Wang, H.; Wang, L.-J.; Yao, J. M.
2018-02-01
The odd-even parity splittings in low-lying parity-doublet states of atomic nuclei with octupole correlations have usually been interpreted as rotational excitations on top of octupole vibration in the language of collective models. In this paper, we report a deep analysis of the odd-even parity splittings in the parity-doublet states of neutron-rich Ba isotopes around neutron number N =88 within a full microscopic framework of beyond-mean-field multireference covariant energy density functional theory. The dynamical correlations related to symmetry restoration and quadrupole-octupole shape fluctuation are taken into account with a generator coordinate method combined with parity, particle-number, and angular-momentum projections. We show that the behavior of odd-even parity splittings is governed by the interplay of rotation, quantum tunneling, and shape evolution. Similar to 224Ra, a picture of rotation-induced octupole shape stabilization in the positive-parity states is exhibited in the neutron-rich Ba isotopes.
Promoting gender parity in basic education: Lessons from a technical cooperation project in Yemen
NASA Astrophysics Data System (ADS)
Yuki, Takako; Mizuno, Keiko; Ogawa, Keiichi; Mihoko, Sakai
2013-06-01
Many girls are not sent to school in Yemen, despite basic education being free as well as compulsory for all children aged 6-15. Aiming to improve girls' enrolment by increasing parental and community involvement, the Japan International Cooperation Agency (JICA) offered a technical cooperation project in June 2005 called Broadening Regional Initiative for Developing Girls' Education (BRIDGE). Phase 1 of this project ran for three and a half years, piloting a participatory school management model supported by school grants in six districts of the Taiz Governorate in the Southwest of Yemen. To find out how successful this approach has been in a traditional society, the authors of this paper analysed the gender parity index (GPI) of the project's pilot schools. Based on data collected at three points in time (in the initial and final years of the project, and two years after the project's end), their findings suggest that interventions in school management which strongly emphasise girls' education can be effective in improving gender parity rather quickly, regardless of the schools' initial conditions. However, the authors also observe that the pilot schools' post-project performance in terms of gender parity is mixed. While the local government allocated budgets for school grants to all pilot schools even after the project's end, training and monitoring activities were cut back. The authors further observe that the variation in performance appears to be significantly correlated with school leaders' initial perceptions of gender equality and with the number of female teachers employed. These findings point to the importance of providing schools with continuous long-term guidance and of monitoring those which implement school improvement programmes.
Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector
NASA Astrophysics Data System (ADS)
Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Bansil, H. S.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M. I.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Bieniek, S. P.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, J.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruschi, M.; Bruscino, N.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Buehrer, F.; Bugge, L.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burghgrave, B.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Cabrera Urbán, S.; Caforio, D.; Cairo, V. M.; Cakir, O.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camarda, S.; Camarri, P.; Cameron, D.; Caminal Armadans, R.; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Cano Bret, M.; Cantero, J.; Cantrill, R.; Cao, T.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Cardarelli, R.; Cardillo, F.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Castaneda-Miranda, E.; Castelli, A.; Castillo Gimenez, V.; Castro, N. F.; Catastini, P.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerio, B. C.; Cerny, K.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chau, C. C.; Chavez Barajas, C. A.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, L.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Childers, J. T.; Chiodini, G.; Chisholm, A. S.; Chislett, R. T.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, P. J.; Clarke, R. N.; Cleland, W.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Cogan, J. G.; Cole, B.; Cole, S.; Colijn, A. P.; Collot, J.; Colombo, T.; Compostella, G.; Conde Muiño, P.; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consonni, S. M.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Côté, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Crispin Ortuzar, M.; Cristinziani, M.; Croft, V.; Crosetti, G.; Cuhadar Donszelmann, T.; Cummings, J.; Curatolo, M.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; D'Auria, S.; D'Onofrio, M.; Da Cunha Sargedas De Sousa, M. J.; Da Via, C.; Dabrowski, W.; Dafinca, A.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Danninger, M.; Dano Hoffmann, M.; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, E.; Davies, M.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Castro, S.; De Cecco, S.; De Groot, N.; de Jong, P.; De la Torre, H.; De Lorenzi, F.; De Nooij, L.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Deigaard, I.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Domenico, A.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Mattia, A.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Dubreuil, E.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Duran Yildiz, H.; Düren, M.; Durglishvili, A.; Duschinger, D.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edson, W.; Edwards, N. C.; Ehrenfeld, W.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Faucci Giannelli, M.; Favareto, A.; Fayard, L.; Federic, P.; Fedin, O. L.; Fedorko, W.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Feremenga, L.; Fernandez Martinez, P.; Fernandez Perez, S.; Ferrando, J.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferreira de Lima, D. E.; Ferrer, A.; Ferrere, D.; Ferretti, C.; Ferretto Parodi, A.; Fiascaris, M.; Fiedler, F.; Filipčič, A.; Filipuzzi, M.; Filthaut, F.; Fincke-Keeler, M.; Finelli, K. D.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, A.; Fischer, C.; Fischer, J.; Fisher, W. C.; Fitzgerald, E. A.; Flaschel, N.; Fleck, I.; Fleischmann, P.; Fleischmann, S.; Fletcher, G. T.; Fletcher, G.; Fletcher, R. R. M.; Flick, T.; Floderus, A.; Flores Castillo, L. R.; Flowerdew, M. J.; Formica, A.; Forti, A.; Fournier, D.; Fox, H.; Fracchia, S.; Francavilla, P.; Franchini, M.; Francis, D.; Franconi, L.; Franklin, M.; Frate, M.; Fraternali, M.; Freeborn, D.; French, S. T.; Friedrich, F.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Fullana Torregrosa, E.; Fulsom, B. G.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gabrielli, A.; Gabrielli, A.; Gadatsch, S.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Galhardo, B.; Gallas, E. J.; Gallop, B. J.; Gallus, P.; Galster, G.; Gan, K. K.; Gao, J.; Gao, Y.; Gao, Y. S.; Garay Walls, F. M.; Garberson, F.; García, C.; García Navarro, J. E.; Garcia-Sciveres, M.; Gardner, R. W.; Garelli, N.; Garonne, V.; Gatti, C.; Gaudiello, A.; Gaudio, G.; Gaur, B.; Gauthier, L.; Gauzzi, P.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gazis, E. N.; Ge, P.; Gecse, Z.; Gee, C. N. P.; Geerts, D. A. A.; Geich-Gimbel, Ch.; Geisler, M. P.; Gemme, C.; Genest, M. H.; Gentile, S.; George, M.; George, S.; Gerbaudo, D.; Gershon, A.; Ghasemi, S.; Ghazlane, H.; Giacobbe, B.; Giagu, S.; Giangiobbe, V.; Giannetti, P.; Gibbard, B.; Gibson, S. M.; Gilchriese, M.; Gillam, T. P. S.; Gillberg, D.; Gilles, G.; Gingrich, D. M.; Giokaris, N.; Giordani, M. P.; Giorgi, F. M.; Giorgi, F. M.; Giraud, P. F.; Giromini, P.; Giugni, D.; Giuliani, C.; Giulini, M.; Gjelsten, B. K.; Gkaitatzis, S.; Gkialas, I.; Gkougkousis, E. L.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glaysher, P. C. F.; Glazov, A.; Goblirsch-Kolb, M.; Goddard, J. R.; Godlewski, J.; Goldfarb, S.; Golling, T.; Golubkov, D.; Gomes, A.; Gonçalo, R.; Goncalves Pinto Firmino Da Costa, J.; Gonella, L.; González de la Hoz, S.; Gonzalez Parra, G.; Gonzalez-Sevilla, S.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Goshaw, A. T.; Gössling, C.; Gostkin, M. I.; Goujdami, D.; Goussiou, A. G.; Govender, N.; Gozani, E.; Grabas, H. M. X.; Graber, L.; Grabowska-Bold, I.; Grafström, P.; Grahn, K.-J.; Gramling, J.; Gramstad, E.; Grancagnolo, S.; Grassi, V.; Gratchev, V.; Gray, H. M.; Graziani, E.; Greenwood, Z. D.; Gregersen, K.; Gregor, I. M.; Grenier, P.; Griffiths, J.; Grillo, A. A.; Grimm, K.; Grinstein, S.; Gris, Ph.; Grivaz, J.-F.; Grohs, J. P.; Grohsjean, A.; Gross, E.; Grosse-Knetter, J.; Grossi, G. C.; Grout, Z. J.; Guan, L.; Guenther, J.; Guescini, F.; Guest, D.; Gueta, O.; Guido, E.; Guillemin, T.; Guindon, S.; Gul, U.; Gumpert, C.; Guo, J.; Guo, Y.; Gupta, S.; Gustavino, G.; Gutierrez, P.; Gutierrez Ortiz, N. G.; Gutschow, C.; Guyot, C.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haber, C.; Hadavand, H. K.; Haddad, N.; Haefner, P.; Hageböck, S.; Hajduk, Z.; Hakobyan, H.; Haleem, M.; Haley, J.; Hall, D.; Halladjian, G.; Hallewell, G. D.; Hamacher, K.; Hamal, P.; Hamano, K.; Hamer, M.; Hamilton, A.; Hamity, G. N.; Hamnett, P. G.; Han, L.; Hanagaki, K.; Hanawa, K.; Hance, M.; Hanke, P.; Hanna, R.; Hansen, J. B.; Hansen, J. D.; Hansen, M. C.; Hansen, P. H.; Hara, K.; Hard, A. S.; Harenberg, T.; Hariri, F.; Harkusha, S.; Harrington, R. D.; Harrison, P. F.; Hartjes, F.; Hasegawa, M.; Hasegawa, S.; Hasegawa, Y.; Hasib, A.; Hassani, S.; Haug, S.; Hauser, R.; Hauswald, L.; Havranek, M.; Hawkes, C. M.; Hawkings, R. J.; Hawkins, A. D.; Hayashi, T.; Hayden, D.; Hays, C. P.; Hays, J. M.; Hayward, H. S.; Haywood, S. J.; Head, S. J.; Heck, T.; Hedberg, V.; Heelan, L.; Heim, S.; Heim, T.; Heinemann, B.; Heinrich, L.; Hejbal, J.; Helary, L.; Hellman, S.; Hellmich, D.; Helsens, C.; Henderson, J.; Henderson, R. C. W.; Heng, Y.; Hengler, C.; Henrichs, A.; Henriques Correia, A. M.; Henrot-Versille, S.; Herbert, G. H.; Hernández Jiménez, Y.; Herrberg-Schubert, R.; Herten, G.; Hertenberger, R.; Hervas, L.; Hesketh, G. G.; Hessey, N. P.; Hetherly, J. W.; Hickling, R.; Higón-Rodriguez, E.; Hill, E.; Hill, J. C.; Hiller, K. H.; Hillier, S. J.; Hinchliffe, I.; Hines, E.; Hinman, R. R.; Hirose, M.; Hirschbuehl, D.; Hobbs, J.; Hod, N.; Hodgkinson, M. C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M. R.; Hoenig, F.; Hohlfeld, M.; Hohn, D.; Holmes, T. R.; Homann, M.; Hong, T. M.; Hooft van Huysduynen, L.; Hopkins, W. H.; Horii, Y.; Horton, A. J.; Hostachy, J.-Y.; Hou, S.; Hoummada, A.; Howard, J.; Howarth, J.; Hrabovsky, M.; Hristova, I.; Hrivnac, J.; Hryn'ova, T.; Hrynevich, A.; Hsu, C.; Hsu, P. J.; Hsu, S.-C.; Hu, D.; Hu, Q.; Hu, X.; Huang, Y.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, T. B.; Hughes, E. W.; Hughes, G.; Huhtinen, M.; Hülsing, T. A.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Iakovidis, G.; Ibragimov, I.; Iconomidou-Fayard, L.; Ideal, E.; Idrissi, Z.; Iengo, P.; Igonkina, O.; Iizawa, T.; Ikegami, Y.; Ikematsu, K.; Ikeno, M.; Ilchenko, Y.; Iliadis, D.; Ilic, N.; Ince, T.; Introzzi, G.; Ioannou, P.; Iodice, M.; Iordanidou, K.; Ippolito, V.; Irles Quiles, A.; Isaksson, C.; Ishino, M.; Ishitsuka, M.; Ishmukhametov, R.; Issever, C.; Istin, S.; Iturbe Ponce, J. M.; Iuppa, R.; Ivarsson, J.; Iwanski, W.; Iwasaki, H.; Izen, J. M.; Izzo, V.; Jabbar, S.; Jackson, B.; Jackson, M.; Jackson, P.; Jaekel, M. R.; Jain, V.; Jakobs, K.; Jakobsen, S.; Jakoubek, T.; Jakubek, J.; Jamin, D. O.; Jana, D. K.; Jansen, E.; Jansky, R.; Janssen, J.; Janus, M.; Jarlskog, G.; Javadov, N.; Javůrek, T.; Jeanty, L.; Jejelava, J.; Jeng, G.-Y.; Jennens, D.; Jenni, P.; Jentzsch, J.; Jeske, C.; Jézéquel, S.; Ji, H.; Jia, J.; Jiang, Y.; Jiggins, S.; Jimenez Pena, J.; Jin, S.; Jinaru, A.; Jinnouchi, O.; Joergensen, M. D.; Johansson, P.; Johns, K. A.; Jon-And, K.; Jones, G.; Jones, R. W. L.; Jones, T. J.; Jongmanns, J.; Jorge, P. M.; Joshi, K. D.; Jovicevic, J.; Ju, X.; Jung, C. A.; Jussel, P.; Juste Rozas, A.; Kaci, M.; Kaczmarska, A.; Kado, M.; Kagan, H.; Kagan, M.; Kahn, S. J.; Kajomovitz, E.; Kalderon, C. W.; Kama, S.; Kamenshchikov, A.; Kanaya, N.; Kaneti, S.; Kantserov, V. A.; Kanzaki, J.; Kaplan, B.; Kaplan, L. S.; Kapliy, A.; Kar, D.; Karakostas, K.; Karamaoun, A.; Karastathis, N.; Kareem, M. J.; Karnevskiy, M.; Karpov, S. N.; Karpova, Z. M.; Karthik, K.; Kartvelishvili, V.; Karyukhin, A. N.; Kashif, L.; Kass, R. D.; Kastanas, A.; Kataoka, Y.; Katre, A.; Katzy, J.; Kawagoe, K.; Kawamoto, T.; Kawamura, G.; Kazama, S.; Kazanin, V. F.; Kazarinov, M. Y.; Keeler, R.; Kehoe, R.; Keller, J. S.; Kempster, J. J.; Keoshkerian, H.; Kepka, O.; Kerševan, B. P.; Kersten, S.; Keyes, R. A.; Khalil-zada, F.; Khandanyan, H.; Khanov, A.; Kharlamov, A. G.; Khoo, T. J.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kim, H. Y.; Kim, H.; Kim, S. H.; Kim, Y.; Kimura, N.; Kind, O. M.; King, B. T.; King, M.; King, S. B.; Kirk, J.; Kiryunin, A. E.; Kishimoto, T.; Kisielewska, D.; Kiss, F.; Kiuchi, K.; Kivernyk, O.; Kladiva, E.; Klein, M. H.; Klein, M.; Klein, U.; Kleinknecht, K.; Klimek, P.; Klimentov, A.; Klingenberg, R.; Klinger, J. A.; Klioutchnikova, T.; Kluge, E.-E.; Kluit, P.; Kluth, S.; Knapik, J.; Kneringer, E.; Knoops, E. B. F. G.; Knue, A.; Kobayashi, A.; Kobayashi, D.; Kobayashi, T.; Kobel, M.; Kocian, M.; Kodys, P.; Koffas, T.; Koffeman, E.; Kogan, L. A.; Kohlmann, S.; Kohout, Z.; Kohriki, T.; Koi, T.; Kolanoski, H.; Koletsou, I.; Komar, A. A.; Komori, Y.; Kondo, T.; Kondrashova, N.; Köneke, K.; König, A. C.; Kono, T.; Konoplich, R.; Konstantinidis, N.; Kopeliansky, R.; Koperny, S.; Köpke, L.; Kopp, A. K.; Korcyl, K.; Kordas, K.; Korn, A.; Korol, A. A.; Korolkov, I.; Korolkova, E. V.; Kortner, O.; Kortner, S.; Kosek, T.; Kostyukhin, V. V.; Kotov, V. M.; Kotwal, A.; Kourkoumeli-Charalampidi, A.; Kourkoumelis, C.; Kouskoura, V.; Koutsman, A.; Kowalewski, R.; Kowalski, T. Z.; Kozanecki, W.; Kozhin, A. S.; Kramarenko, V. A.; Kramberger, G.; Krasnopevtsev, D.; Krasny, M. W.; Krasznahorkay, A.; Kraus, J. K.; Kravchenko, A.; Kreiss, S.; Kretz, M.; Kretzschmar, J.; Kreutzfeldt, K.; Krieger, P.; Krizka, K.; Kroeninger, K.; Kroha, H.; Kroll, J.; Kroseberg, J.; Krstic, J.; Kruchonak, U.; Krüger, H.; Krumnack, N.; Krumshteyn, Z. V.; Kruse, A.; Kruse, M. C.; Kruskal, M.; Kubota, T.; Kucuk, H.; Kuday, S.; Kuehn, S.; Kugel, A.; Kuger, F.; Kuhl, A.; Kuhl, T.; Kukhtin, V.; Kulchitsky, Y.; Kuleshov, S.; Kuna, M.; Kunigo, T.; Kupco, A.; Kurashige, H.; Kurochkin, Y. A.; Kus, V.; Kuwertz, E. S.; Kuze, M.; Kvita, J.; Kwan, T.; Kyriazopoulos, D.; La Rosa, A.; La Rosa Navarro, J. L.; La Rotonda, L.; Lacasta, C.; Lacava, F.; Lacey, J.; Lacker, H.; Lacour, D.; Lacuesta, V. R.; Ladygin, E.; Lafaye, R.; Laforge, B.; Lagouri, T.; Lai, S.; Lambourne, L.; Lammers, S.; Lampen, C. L.; Lampl, W.; Lançon, E.; Landgraf, U.; Landon, M. P. J.; Lang, V. S.; Lange, J. C.; Lankford, A. J.; Lanni, F.; Lantzsch, K.; Lanza, A.; Laplace, S.; Lapoire, C.; Laporte, J. F.; Lari, T.; Lasagni Manghi, F.; Lassnig, M.; Laurelli, P.; Lavrijsen, W.; Law, A. T.; Laycock, P.; Lazovich, T.; Le Dortz, O.; Le Guirriec, E.; Le Menedeu, E.; LeBlanc, M.; LeCompte, T.; Ledroit-Guillon, F.; Lee, C. A.; Lee, S. C.; Lee, L.; Lefebvre, G.; Lefebvre, M.; Legger, F.; Leggett, C.; Lehan, A.; Lehmann Miotto, G.; Lei, X.; Leight, W. A.; Leisos, A.; Leister, A. G.; Leite, M. A. L.; Leitner, R.; Lellouch, D.; Lemmer, B.; Leney, K. J. C.; Lenz, T.; Lenzi, B.; Leone, R.; Leone, S.; Leonidopoulos, C.; Leontsinis, S.; Leroy, C.; Lester, C. G.; Levchenko, M.; Levêque, J.; Levin, D.; Levinson, L. J.; Levy, M.; Lewis, A.; Leyko, A. M.; Leyton, M.; Li, B.; Li, H.; Li, H. L.; Li, L.; Li, L.; Li, S.; Li, Y.; Liang, Z.; Liao, H.; Liberti, B.; Liblong, A.; Lichard, P.; Lie, K.; Liebal, J.; Liebig, W.; Limbach, C.; Limosani, A.; Lin, S. C.; Lin, T. H.; Linde, F.; Lindquist, B. E.; Linnemann, J. T.; Lipeles, E.; Lipniacka, A.; Lisovyi, M.; Liss, T. M.; Lissauer, D.; Lister, A.; Litke, A. M.; Liu, B.; Liu, D.; Liu, H.; Liu, J.; Liu, J. B.; Liu, K.; Liu, L.; Liu, M.; Liu, M.; Liu, Y.; Livan, M.; Lleres, A.; Llorente Merino, J.; Lloyd, S. L.; Lo Sterzo, F.; Lobodzinska, E.; Loch, P.; Lockman, W. S.; Loebinger, F. K.; Loevschall-Jensen, A. E.; Loginov, A.; Lohse, T.; Lohwasser, K.; Lokajicek, M.; Long, B. A.; Long, J. D.; Long, R. E.; Looper, K. A.; Lopes, L.; Lopez Mateos, D.; Lopez Paredes, B.; Lopez Paz, I.; Lorenz, J.; Lorenzo Martinez, N.; Losada, M.; Loscutoff, P.; Lösel, P. J.; Lou, X.; Lounis, A.; Love, J.; Love, P. A.; Lu, N.; Lubatti, H. J.; Luci, C.; Lucotte, A.; Luehring, F.; Lukas, W.; Luminari, L.; Lundberg, O.; Lund-Jensen, B.; Lynn, D.; Lysak, R.; Lytken, E.; Ma, H.; Ma, L. L.; Maccarrone, G.; Macchiolo, A.; Macdonald, C. M.; Machado Miguens, J.; Macina, D.; Madaffari, D.; Madar, R.; Maddocks, H. J.; Mader, W. F.; Madsen, A.; Maeland, S.; Maeno, T.; Maevskiy, A.; Magradze, E.; Mahboubi, K.; Mahlstedt, J.; Maiani, C.; Maidantchik, C.; Maier, A. A.; Maier, T.; Maio, A.; Majewski, S.; Makida, Y.; Makovec, N.; Malaescu, B.; Malecki, Pa.; Maleev, V. P.; Malek, F.; Mallik, U.; Malon, D.; Malone, C.; Maltezos, S.; Malyshev, V. M.; Malyukov, S.; Mamuzic, J.; Mancini, G.; Mandelli, B.; Mandelli, L.; Mandić, I.; Mandrysch, R.; Maneira, J.; Manfredini, A.; Manhaes de Andrade Filho, L.; Manjarres Ramos, J.; Mann, A.; Manning, P. M.; Manousakis-Katsikakis, A.; Mansoulie, B.; Mantifel, R.; Mantoani, M.; Mapelli, L.; March, L.; Marchiori, G.; Marcisovsky, M.; Marino, C. P.; Marjanovic, M.; Marley, D. E.; Marroquim, F.; Marsden, S. P.; Marshall, Z.; Marti, L. F.; Marti-Garcia, S.; Martin, B.; Martin, T. A.; Martin, V. J.; Martin dit Latour, B.; Martinez, M.; Martin-Haugh, S.; Martoiu, V. S.; Martyniuk, A. C.; Marx, M.; Marzano, F.; Marzin, A.; Masetti, L.; Mashimo, T.; Mashinistov, R.; Masik, J.; Maslennikov, A. L.; Massa, I.; Massa, L.; Massol, N.; Mastrandrea, P.; Mastroberardino, A.; Masubuchi, T.; Mättig, P.; Mattmann, J.; Maurer, J.; Maxfield, S. J.; Maximov, D. A.; Mazini, R.; Mazza, S. M.; Mazzaferro, L.; Mc Goldrick, G.; Mc Kee, S. P.; McCarn, A.; McCarthy, R. L.; McCarthy, T. G.; McCubbin, N. A.; McFarlane, K. W.; Mcfayden, J. A.; Mchedlidze, G.; McMahon, S. J.; McPherson, R. A.; Medinnis, M.; Meehan, S.; Mehlhase, S.; Mehta, A.; Meier, K.; Meineck, C.; Meirose, B.; Mellado Garcia, B. R.; Meloni, F.; Mengarelli, A.; Menke, S.; Meoni, E.; Mercurio, K. M.; Mergelmeyer, S.; Mermod, P.; Merola, L.; Meroni, C.; Merritt, F. S.; Messina, A.; Metcalfe, J.; Mete, A. S.; Meyer, C.; Meyer, C.; Meyer, J.-P.; Meyer, J.; Middleton, R. P.; Miglioranzi, S.; Mijović, L.; Mikenberg, G.; Mikestikova, M.; Mikuž, M.; Milesi, M.; Milic, A.; Miller, D. W.; Mills, C.; Milov, A.; Milstead, D. A.; Minaenko, A. A.; Minami, Y.; Minashvili, I. A.; Mincer, A. I.; Mindur, B.; Mineev, M.; Ming, Y.; Mir, L. M.; Mitani, T.; Mitrevski, J.; Mitsou, V. A.; Miucci, A.; Miyagawa, P. S.; Mjörnmark, J. U.; Moa, T.; Mochizuki, K.; Mohapatra, S.; Mohr, W.; Molander, S.; Moles-Valls, R.; Mönig, K.; Monini, C.; Monk, J.; Monnier, E.; Montejo Berlingen, J.; Monticelli, F.; Monzani, S.; Moore, R. W.; Morange, N.; Moreno, D.; Moreno Llácer, M.; Morettini, P.; Morgenstern, M.; Morii, M.; Morinaga, M.; Morisbak, V.; Moritz, S.; Morley, A. K.; Mornacchi, G.; Morris, J. D.; Mortensen, S. S.; Morton, A.; Morvaj, L.; Mosidze, M.; Moss, J.; Motohashi, K.; Mount, R.; Mountricha, E.; Mouraviev, S. V.; Moyse, E. J. W.; Muanza, S.; Mudd, R. D.; Mueller, F.; Mueller, J.; Mueller, R. S. P.; Mueller, T.; Muenstermann, D.; Mullen, P.; Mullier, G. A.; Murillo Quijada, J. A.; Murray, W. J.; Musheghyan, H.; Musto, E.; Myagkov, A. G.; Myska, M.; Nackenhorst, O.; Nadal, J.; Nagai, K.; Nagai, R.; Nagai, Y.; Nagano, K.; Nagarkar, A.; Nagasaka, Y.; Nagata, K.; Nagel, M.; Nagy, E.; Nairz, A. M.; Nakahama, Y.; Nakamura, K.; Nakamura, T.; Nakano, I.; Namasivayam, H.; Naranjo Garcia, R. F.; Narayan, R.; Naumann, T.; Navarro, G.; Nayyar, R.; Neal, H. A.; Nechaeva, P. Yu.; Neep, T. J.; Nef, P. D.; Negri, A.; Negrini, M.; Nektarijevic, S.; Nellist, C.; Nelson, A.; Nemecek, S.; Nemethy, P.; Nepomuceno, A. A.; Nessi, M.; Neubauer, M. S.; Neumann, M.; Neves, R. M.; Nevski, P.; Newman, P. R.; Nguyen, D. H.; Nickerson, R. B.; Nicolaidou, R.; Nicquevert, B.; Nielsen, J.; Nikiforou, N.; Nikiforov, A.; Nikolaenko, V.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, J. K.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nisius, R.; Nobe, T.; Nomachi, M.; Nomidis, I.; Nooney, T.; Norberg, S.; Nordberg, M.; Novgorodova, O.; Nowak, S.; Nozaki, M.; Nozka, L.; Ntekas, K.; Nunes Hanninger, G.; Nunnemann, T.; Nurse, E.; Nuti, F.; O'Brien, B. J.; O'grady, F.; O'Neil, D. C.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Obermann, T.; Ocariz, J.; Ochi, A.; Ochoa, I.; Ochoa-Ricoux, J. P.; Oda, S.; Odaka, S.; Ogren, H.; Oh, A.; Oh, S. H.; Ohm, C. C.; Ohman, H.; Oide, H.; Okamura, W.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olariu, A.; Olivares Pino, S. A.; Oliveira Damazio, D.; Oliver Garcia, E.; Olszewski, A.; Olszowska, J.; Onofre, A.; Onyisi, P. U. E.; Oram, C. J.; Oreglia, M. J.; Oren, Y.; Orestano, D.; Orlando, N.; Oropeza Barrera, C.; Orr, R. S.; Osculati, B.; Ospanov, R.; Otero y Garzon, G.; Otono, H.; Ouchrif, M.; Ouellette, E. A.; Ould-Saada, F.; Ouraou, A.; Oussoren, K. P.; Ouyang, Q.; Ovcharova, A.; Owen, M.; Owen, R. E.; Ozcan, V. E.; Ozturk, N.; Pachal, K.; Pacheco Pages, A.; Padilla Aranda, C.; Pagáčová, M.; Pagan Griso, S.; Paganis, E.; Paige, F.; Pais, P.; Pajchel, K.; Palacino, G.; Palestini, S.; Palka, M.; Pallin, D.; Palma, A.; Pan, Y. B.; Panagiotopoulou, E.; Pandini, C. E.; Panduro Vazquez, J. G.; Pani, P.; Panitkin, S.; Pantea, D.; Paolozzi, L.; Papadopoulou, Th. D.; Papageorgiou, K.; Paramonov, A.; Paredes Hernandez, D.; Parker, M. A.; Parker, K. A.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pasqualucci, E.; Passaggio, S.; Pastore, F.; Pastore, Fr.; Pásztor, G.; Pataraia, S.; Patel, N. D.; Pater, J. R.; Pauly, T.; Pearce, J.; Pearson, B.; Pedersen, L. E.; Pedersen, M.; Pedraza Lopez, S.; Pedro, R.; Peleganchuk, S. V.; Pelikan, D.; Penc, O.; Peng, C.; Peng, H.; Penning, B.; Penwell, J.; Perepelitsa, D. V.; Perez Codina, E.; Pérez García-Estañ, M. T.; Perini, L.; Pernegger, H.; Perrella, S.; Peschke, R.; Peshekhonov, V. D.; Peters, K.; Peters, R. F. Y.; Petersen, B. A.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petrolo, E.; Petrucci, F.; Pettersson, N. E.; Pezoa, R.; Phillips, P. W.; Piacquadio, G.; Pianori, E.; Picazio, A.; Piccaro, E.; Piccinini, M.; Pickering, M. A.; Piegaia, R.; Pignotti, D. T.; Pilcher, J. E.; Pilkington, A. D.; Pina, J.; Pinamonti, M.; Pinfold, J. L.; Pingel, A.; Pinto, B.; Pires, S.; Pirumov, H.; Pitt, M.; Pizio, C.; Plazak, L.; Pleier, M.-A.; Pleskot, V.; Plotnikova, E.; Plucinski, P.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Pralavorio, P.; Pranko, A.; Prasad, S.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Proissl, M.; Prokofiev, K.; Prokoshin, F.; Protopapadaki, E.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Ptacek, E.; Puddu, D.; Pueschel, E.; Puldon, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quarrie, D. R.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Raymond, M.; Read, A. L.; Readioff, N. P.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Rehnisch, L.; Reisin, H.; Relich, M.; Rembser, C.; Ren, H.; Renaud, A.; Rescigno, M.; Resconi, S.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Roe, S.; Røhne, O.; Rolli, S.; Romaniouk, A.; Romano, M.; Romano Saez, S. M.; Romero Adam, E.; Rompotis, N.; Ronzani, M.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, P.; Rosendahl, P. L.; Rosenthal, O.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rubinskiy, I.; Rud, V. I.; Rudolph, C.; Rudolph, M. S.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryder, N. C.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Saddique, A.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Saimpert, M.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salamon, A.; Saleem, M.; Salek, D.; Sales De Bruin, P. H.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sampsonidis, D.; Sanchez, A.; Sánchez, J.; Sanchez Martinez, V.; Sandaker, H.; Sandbach, R. L.; Sander, H. G.; Sanders, M. P.; Sandhoff, M.; Sandoval, C.; Sandstroem, R.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Santoyo Castillo, I.; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sasaki, Y.; Sato, K.; Sauvage, G.; Sauvan, E.; Savage, G.; Savard, P.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schaefer, D.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmidt, E.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitt, S.; Schneider, B.; Schnellbach, Y. J.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schorlemmer, A. L. S.; Schott, M.; Schouten, D.; Schovancova, J.; Schramm, S.; Schreyer, M.; Schroeder, C.; Schuh, N.; Schultens, M. J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwarz, T. A.; Schwegler, Ph.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciacca, F. G.; Scifo, E.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Sedov, G.; Sedykh, E.; Seema, P.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Seliverstov, D. M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Serre, T.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shiyakova, M.; Shmeleva, A.; Shoaleh Saadi, D.; Shochet, M. J.; Shojaii, S.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Shushkevich, S.; Sicho, P.; Sidebo, P. E.; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silver, Y.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Simoniello, R.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snidero, G.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Song, H. Y.; Soni, N.; Sood, A.; Sopczak, A.; Sopko, B.; Sopko, V.; Sorin, V.; Sosa, D.; Sosebee, M.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spanò, F.; Spearman, W. R.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; Spreitzer, T.; St. Denis, R. D.; Staerz, S.; Stahlman, J.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staszewski, R.; Stavina, P.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramaniam, R.; Succurro, A.; Sugaya, Y.; Suhr, C.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swedish, S.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Taccini, C.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tam, J. Y. C.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tannenwald, B. B.; Tannoury, N.; Tapprogge, S.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, F. E.; Taylor, G. N.; Taylor, W.; Teischinger, F. A.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, R. J.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Thun, R. P.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tiouchichine, E.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tollefson, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; True, P.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turra, R.; Turvey, A. J.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Ueda, I.; Ueno, R.; Ughetto, M.; Ugland, M.; Uhlenbrock, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J. A.; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; Van Der Leeuw, R.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vannucci, F.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veloce, L. M.; Veloso, F.; Velz, T.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, T.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Warsinsky, M.; Washbrook, A.; Wasicki, C.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Wharton, A. M.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, A.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamada, M.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yao, W.-M.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yurkewicz, A.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zwalinski, L.
2015-10-01
Studies of the spin, parity and tensor couplings of the Higgs boson in the H → ZZ^{*} → 4 ℓ, H → WW^{*} → e ν μ ν and H → γ γ decay processes at the LHC are presented. The investigations are based on 25fb^{-1} of pp collision data collected by the ATLAS experiment at √{s}=7 TeV and √{s}=8 TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers JP=0+, is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at more than 99.9 % confidence level. Using the H → ZZ^{*} → 4 ℓ and H → WW^{*} → e ν μ ν decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. The observed distributions of variables sensitive to the non-SM tensor couplings are compatible with the SM predictions and constraints on the non-SM couplings are derived.
Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector
DOE Office of Scientific and Technical Information (OSTI.GOV)
Aad, G.
Studies of the spin, parity and tensor couplings of the Higgs boson in the H→ZZ*→4ℓ, H→WW*→eνμν and H→γγ decay processes at the LHC are presented. The investigations are based on 25fb –1 of pp collision data collected by the ATLAS experiment at √s=7 TeV and √s=8 TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers JP=0 +, is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at moremore » than 99.9 % confidence level. Using the H→ZZ*→4ℓ and H→WW*→eνμν decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. Thus, the observed distributions of variables sensitive to the non SM tensor couplings are compatible with the SM predictions and constraints on the non SM couplings are derived.« less
Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector
Aad, G.
2015-10-06
Studies of the spin, parity and tensor couplings of the Higgs boson in the H→ZZ*→4ℓ, H→WW*→eνμν and H→γγ decay processes at the LHC are presented. The investigations are based on 25fb –1 of pp collision data collected by the ATLAS experiment at √s=7 TeV and √s=8 TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers JP=0 +, is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons. All tested alternative models are excluded in favour of the SM Higgs boson hypothesis at moremore » than 99.9 % confidence level. Using the H→ZZ*→4ℓ and H→WW*→eνμν decays, the tensor structure of the interaction between the spin-0 boson and the SM vector bosons is also investigated. Thus, the observed distributions of variables sensitive to the non SM tensor couplings are compatible with the SM predictions and constraints on the non SM couplings are derived.« less
Parity-expanded variational analysis for nonzero momentum
NASA Astrophysics Data System (ADS)
Stokes, Finn M.; Kamleh, Waseem; Leinweber, Derek B.; Mahbub, M. Selim; Menadue, Benjamin J.; Owen, Benjamin J.
2015-12-01
In recent years, the use of variational analysis techniques in lattice QCD has been demonstrated to be successful in the investigation of the rest-mass spectrum of many hadrons. However, due to parity mixing, more care must be taken for investigations of boosted states to ensure that the projected correlation functions provided by the variational analysis correspond to the same states at zero momentum. In this paper we present the parity-expanded variational analysis (PEVA) technique, a novel method for ensuring the successful and consistent isolation of boosted baryons through a parity expansion of the operator basis used to construct the correlation matrix.
Neutrino mixing in a left-right model
NASA Astrophysics Data System (ADS)
Martins Simões, J. A.; Ponciano, J. A.
We study the mixing among different generations of massive neutrino fields in a
W$${'}$$ signatures with odd Higgs particles
Dobrescu, Bogdan A.; Peterson, Andrea D.
2014-08-13
We point out that W' bosons may decay predominantly into Higgs particles associated with their broken gauge symmetry. We demonstrate this in a renormalizable model where the W' and W couplings to fermions differ only by an overall normalization. This "meta-sequential" W' boson decays into a scalar pair, with the charged one subsequently decaying into a W boson and a neutral scalar. These scalars are odd under a parity of the Higgs sector, which consists of a complex bidoublet and a doublet. Finally, the W' and Z' bosons have the same mass and branching fractions into scalars, and may showmore » up at the LHC in final states involving one or two electroweak bosons and missing transverse energy.« less
A model with isospin doublet U(1)D gauge symmetry
NASA Astrophysics Data System (ADS)
Nomura, Takaaki; Okada, Hiroshi
2018-05-01
We propose a model with an extra isospin doublet U(1)D gauge symmetry, in which we introduce several extra fermions with odd parity under a discrete Z2 symmetry in order to cancel the gauge anomalies out. A remarkable issue is that we impose nonzero U(1)D charge to the Standard Model Higgs, and it gives the most stringent constraint to the vacuum expectation value of a scalar field breaking the U(1)D symmetry that is severer than the LEP bound. We then explore relic density of a Majorana dark matter candidate without conflict of constraints from lepton flavor violating processes. A global analysis is carried out to search for parameters which can accommodate with the observed data.
The dark side of flipped trinification
NASA Astrophysics Data System (ADS)
Dong, P. V.; Huong, D. T.; Queiroz, Farinaldo S.; Valle, José W. F.; Vaquera-Araujo, C. A.
2018-04-01
We propose a model which unifies the Left-Right symmetry with the SU(3) L gauge group, called flipped trinification, and based on the SU(3) C ⊗ SU(3) L ⊗ SU(3) R ⊗ U(1) X gauge group. The model inherits the interesting features of both symmetries while elegantly explaining the origin of the matter parity, W P = (-1)3( B- L)+2 s , and dark matter stability. We develop the details of the spontaneous symmetry breaking mechanism in the model, determining the relevant mass eigenstates, and showing how neutrino masses are easily generated via the seesaw mechanism. Moreover, we introduce viable dark matter candidates, encompassing a fermion, scalar and possibly vector fields, leading to a potentially novel dark matter phenomenology.
Many-body physics using cold atoms
NASA Astrophysics Data System (ADS)
Sundar, Bhuvanesh
Advances in experiments on dilute ultracold atomic gases have given us access to highly tunable quantum systems. In particular, there have been substantial improvements in achieving different kinds of interaction between atoms. As a result, utracold atomic gases oer an ideal platform to simulate many-body phenomena in condensed matter physics, and engineer other novel phenomena that are a result of the exotic interactions produced between atoms. In this dissertation, I present a series of studies that explore the physics of dilute ultracold atomic gases in different settings. In each setting, I explore a different form of the inter-particle interaction. Motivated by experiments which induce artificial spin-orbit coupling for cold fermions, I explore this system in my first project. In this project, I propose a method to perform universal quantum computation using the excitations of interacting spin-orbit coupled fermions, in which effective p-wave interactions lead to the formation of a topological superfluid. Motivated by experiments which explore the physics of exotic interactions between atoms trapped inside optical cavities, I explore this system in a second project. I calculate the phase diagram of lattice bosons trapped in an optical cavity, where the cavity modes mediates effective global range checkerboard interactions between the atoms. I compare this phase diagram with one that was recently measured experimentally. In two other projects, I explore quantum simulation of condensed matter phenomena due to spin-dependent interactions between particles. I propose a method to produce tunable spin-dependent interactions between atoms, using an optical Feshbach resonance. In one project, I use these spin-dependent interactions in an ultracold Bose-Fermi system, and propose a method to produce the Kondo model. I propose an experiment to directly observe the Kondo effect in this system. In another project, I propose using lattice bosons with a large hyperfine spin, which have Feshbach-induced spin-dependent interactions, to produce a quantum dimer model. I propose an experiment to detect the ground state in this system. In a final project, I develop tools to simulate the dynamics of fermionic superfluids in which fermions interact via a short-range interaction.
Tensor Network Wavefunctions for Topological Phases
NASA Astrophysics Data System (ADS)
Ware, Brayden Alexander
The combination of quantum effects and interactions in quantum many-body systems can result in exotic phases with fundamentally entangled ground state wavefunctions--topological phases. Topological phases come in two types, both of which will be studied in this thesis. In topologically ordered phases, the pattern of entanglement in the ground state wavefunction encodes the statistics of exotic emergent excitations, a universal indicator of a phase that is robust to all types of perturbations. In symmetry protected topological phases, the entanglement instead encodes a universal response of the system to symmetry defects, an indicator that is robust only to perturbations respecting the protecting symmetry. Finding and creating these phases in physical systems is a motivating challenge that tests all aspects--analytical, numerical, and experimental--of our understanding of the quantum many-body problem. Nearly three decades ago, the creation of simple ansatz wavefunctions--such as the Laughlin fractional quantum hall state, the AKLT state, and the resonating valence bond state--spurred analytical understanding of both the role of entanglement in topological physics and physical mechanisms by which it can arise. However, quantitative understanding of the relevant phase diagrams is still challenging. For this purpose, tensor networks provide a toolbox for systematically improving wavefunction ansatz while still capturing the relevant entanglement properties. In this thesis, we use the tools of entanglement and tensor networks to analyze ansatz states for several proposed new phases. In the first part, we study a featureless phase of bosons on the honeycomb lattice and argue that this phase can be topologically protected under any one of several distinct subsets of the crystalline lattice symmetries. We discuss methods of detecting such phases with entanglement and without. In the second part, we consider the problem of constructing fixed-point wavefunctions for intrinsically fermionic topological phases, i.e. topological phases contructed out of fermions with a nontrivial response to fermion parity defects. A zero correlation length wavefunction and a commuting projector Hamiltonian that realizes this wavefunction as its ground state are constructed. Using an appropriate generalization of the minimally entangled states method for extraction of topological order from the ground states on a torus to the intrinsically fermionic case, we fully characterize the corresponding topological order as Ising x (px - ipy). We argue that this phase can be captured using fermionic tensor networks, expanding the applicability of tensor network methods.
Three-component fermions with surface Fermi arcs in tungsten carbide
NASA Astrophysics Data System (ADS)
Ma, J.-Z.; He, J.-B.; Xu, Y.-F.; Lv, B. Q.; Chen, D.; Zhu, W.-L.; Zhang, S.; Kong, L.-Y.; Gao, X.; Rong, L.-Y.; Huang, Y.-B.; Richard, P.; Xi, C.-Y.; Choi, E. S.; Shao, Y.; Wang, Y.-L.; Gao, H.-J.; Dai, X.; Fang, C.; Weng, H.-M.; Chen, G.-F.; Qian, T.; Ding, H.
2018-04-01
Topological Dirac and Weyl semimetals not only host quasiparticles analogous to the elementary fermionic particles in high-energy physics, but also have a non-trivial band topology manifested by gapless surface states, which induce exotic surface Fermi arcs1,2. Recent advances suggest new types of topological semimetal, in which spatial symmetries protect gapless electronic excitations without high-energy analogues3-11. Here, using angle-resolved photoemission spectroscopy, we observe triply degenerate nodal points near the Fermi level of tungsten carbide with space group
Generic calculation of two-body partial decay widths at the full one-loop level
NASA Astrophysics Data System (ADS)
Goodsell, Mark D.; Liebler, Stefan; Staub, Florian
2017-11-01
We describe a fully generic implementation of two-body partial decay widths at the full one-loop level in the SARAH and SPheno framework compatible with most supported models. It incorporates fermionic decays to a fermion and a scalar or a gauge boson as well as scalar decays into two fermions, two gauge bosons, two scalars or a scalar and a gauge boson. We present the relevant generic expressions for virtual and real corrections. Whereas wave-function corrections are determined from on-shell conditions, the parameters of the underlying model are by default renormalised in a \\overline{ {DR}} (or \\overline{ {MS}}) scheme. However, the user can also define model-specific counter-terms. As an example we discuss the renormalisation of the electric charge in the Thomson limit for top-quark decays in the standard model. One-loop-induced decays are also supported. The framework additionally allows the addition of mass and mixing corrections induced at higher orders for the involved external states. We explain our procedure to cancel infrared divergences for such cases, which is achieved through an infrared counter-term taking into account corrected Goldstone boson vertices. We compare our results for sfermion, gluino and Higgs decays in the minimal supersymmetric standard model (MSSM) against the public codes SFOLD, FVSFOLD and HFOLD and explain observed differences. Radiatively induced gluino and neutralino decays are compared against the original implementation in SPheno in the MSSM. We exactly reproduce the results of the code CNNDecays for decays of neutralinos and charginos in R-parity violating models. The new version SARAH 4.11.0 by default includes the calculation of two-body decay widths at the full one-loop level. Current limitations for certain model classes are described.
A rationale for long-lived quarks and leptons at the LHC: low energy flavour theory
NASA Astrophysics Data System (ADS)
Éboli, O. J. P.; Savoy, C. A.; Funchal, R. Zukanovich
2012-02-01
In the framework of gauged flavour symmetries, new fermions in parity symmetric representations of the standard model are generically needed for the compensation of mixed anomalies. The key point is that their masses are also protected by flavour symmetries and some of them are expected to lie way below the flavour symmetry breaking scale(s), which has to occur many orders of magnitude above the electroweak scale to be compatible with the available data from flavour changing neutral currents and CP violation experiments. We argue that, actually, some of these fermions would plausibly get masses within the LHC range. If they are taken to be heavy quarks and leptons, in (bi)-fundamental representations of the standard model symmetries, their mixings with the light ones are strongly constrained to be very small by electroweak precision data. The alternative chosen here is to exactly forbid such mixings by breaking of flavour symmetries into an exact discrete symmetry, the so-called proton-hexality, primarily suggested to avoid proton decay. As a consequence of the large value needed for the flavour breaking scale, those heavy particles are long-lived and rather appropriate for the current and future searches at the LHC for quasi-stable hadrons and leptons. In fact, the LHC experiments have already started to look for them.
Numerical studies of the Bethe-Salpeter equation for a two-fermion bound state
NASA Astrophysics Data System (ADS)
de Paula, W.; Frederico, T.; Salmè, G.; Viviani, M.
2018-03-01
Some recent advances on the solution of the Bethe-Salpeter equation (BSE) for a two-fermion bound system directly in Minkowski space are presented. The calculations are based on the expression of the Bethe-Salpeter amplitude in terms of the so-called Nakanishi integral representation and on the light-front projection (i.e. the integration of the light-front variable k - = k 0 - k 3). The latter technique allows for the analytically exact treatment of the singularities plaguing the two-fermion BSE in Minkowski space. The good agreement observed between our results and those obtained using other existing numerical methods, based on both Minkowski and Euclidean space techniques, fully corroborate our analytical treatment.
Scattering of massless fermions by Schwarzschild and Reissner-Nordström black holes
NASA Astrophysics Data System (ADS)
Sporea, Ciprian A.
2017-12-01
We study the scattering of massless Dirac fermions by Schwarzschild and Reissner-Nordström black holes. This is done by applying partial wave analysis to the scattering modes obtained after solving the massless Dirac equation in the asymptotic regions of the two black hole geometries. We successfully obtain analytic phase shifts, with the help of which the scattering cross section is computed. The glory and spiral scattering phenomena are shown to be present, as in the case of massive fermion scattering by black holes. Supported by a grant of the Ministry of National Education and Scientific Research, RDI Programme for Space Technology and Advanced Research - STAR, project number 181/20.07.2017
NASA Astrophysics Data System (ADS)
Andrews, Bartholomew; Möller, Gunnar
2018-01-01
We study the stability of composite fermion fractional quantum Hall states in Harper-Hofstadter bands with Chern number |C |>1 . From composite fermion theory, states are predicted to be found at filling factors ν =r /(k r |C |+1 ),r ∈Z , with k =1 for bosons and k =2 for fermions. Here, we closely analyze these series in both cases, with contact interactions for bosons and nearest-neighbor interactions for (spinless) fermions. In particular, we analyze how the many-body gap scales as the bands are tuned to the effective continuum limit of Chern number |C | bands, realized near flux density nϕ=1 /|C | . Near these points, the Hofstadter model requires large magnetic unit cells that yield bands with perfectly flat dispersion and Berry curvature. We exploit the known scaling of energies in the effective continuum limit in order to maintain a fixed square aspect ratio in finite-size calculations. Based on exact diagonalization calculations of the band-projected Hamiltonian for these lattice geometries, we show that for both bosons and fermions, the vast majority of finite-size spectra yield the ground-state degeneracy predicted by composite fermion theory. For the chosen interactions, we confirm that states with filling factor ν =1 /(k |C |+1 ) are the most robust and yield a clear gap in the thermodynamic limit. For bosons with contact interactions in |C |=2 and |C |=3 bands, our data for the composite fermion states are compatible with a finite gap in the thermodynamic limit. We also report new evidence for gapped incompressible states stabilized for fermions with nearest-neighbor interactions in |C |>1 bands. For cases with a clear gap, we confirm that the thermodynamic limit commutes with the effective continuum limit within finite-size error bounds. We analyze the nature of the correlation functions for the Abelian composite fermion states and find that the correlation functions for |C |>1 states are smooth functions for positions separated by |C | sites along both axes, giving rise to |C| 2 sheets; some of which can be related by inversion symmetry. We also comment on two cases which are associated with a bosonic integer quantum Hall effect (BIQHE): For ν =2 in |C |=1 bands, we find a strong competing state with a higher ground-state degeneracy, so no clear BIQHE is found in the band-projected Hofstadter model; for ν =1 in |C |=2 bands, we present additional data confirming the existence of a BIQHE state.
Vacuum Cherenkov radiation for Lorentz-violating fermions
NASA Astrophysics Data System (ADS)
Schreck, M.
2017-11-01
The current work focuses on the process of vacuum Cherenkov radiation for Lorentz-violating fermions that are described by the minimal standard-model extension (SME). To date, most considerations of this important hypothetical process have been restricted to Lorentz-violating photons, as the necessary theoretical tools for the SME fermion sector have not been available. With their development in a very recent paper, we are now in a position to compute the decay rates based on a modified Dirac theory. Two realizations of the Cherenkov process are studied. In the first scenario, the spin projection of the incoming fermion is assumed to be conserved, and in the second, the spin projection is allowed to flip. The first type of process is shown to be still forbidden for the dimensionful a and b coefficients where there are strong indications that it is energetically disallowed for the H coefficients, as well. However, it is rendered possible for the dimensionless c , d , e , f , and g coefficients. For large initial fermion energies, the decay rates for the c and d coefficients were found to grow linearly with momentum and to be linearly suppressed by the smallness of the Lorentz-violating coefficient where for the e , f , and g coefficients this suppression is even quadratic. The decay rates vanish in the vicinity of the threshold, as expected. The decay including a fermion spin-flip plays a role for the spin-nondegenerate operators and it was found to occur for the dimensionful b and H coefficients as well as for the dimensionless d and g . The characteristics of this process differ much from the properties of the spin-conserving one, e.g., there is no threshold. Based on experimental data of ultra-high-energy cosmic rays, new constraints on Lorentz violation in the quark sector are obtained from the thresholds. However, it does not seem to be possible to derive bounds from the spin-flip decays. This work reveals the usefulness of the quantum field theoretic methods recently developed to study the phenomenology of high-energy fermions within the framework of the SME.
McGinty, Emma E; Busch, Susan H; Stuart, Elizabeth A; Huskamp, Haiden A; Gibson, Teresa B; Goldman, Howard H; Barry, Colleen L
2015-08-01
The Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008 requires commercial insurers providing group coverage for substance use disorder services to offer benefits for those services at a level equal to those for medical or surgical benefits. Unlike previous parity policies instituted for federal employees and in individual states, the law extends parity to out-of-network services. We conducted an interrupted time-series analysis using insurance claims from large self-insured employers to evaluate whether federal parity was associated with changes in out-of-network treatment for 525,620 users of substance use disorder services. Federal parity was associated with an increased probability of using out-of-network services, an increased average number of out-of-network outpatient visits, and increased average total spending on out-of-network services among users of those services. Our findings were broadly consistent with the contention of federal parity proponents that extending parity to out-of-network services would broaden access to substance use disorder care obtained outside of plan networks. Project HOPE—The People-to-People Health Foundation, Inc.
Cascade of Quantum Transitions and Magnetocaloric Anomalies in an Open Nanowire
NASA Astrophysics Data System (ADS)
Val'kov, V. V.; Mitskan, V. A.; Shustin, M. S.
2017-12-01
A sequence of magnetocaloric anomalies occurring with the change in a magnetic field H is predicted for an open nanowire with the Rashba spin-orbit coupling and the induced superconducting pairing potential. The nature of such anomalies is due to the cascade of quantum transitions related to the successive changes in the fermion parity of the nanowire ground state with the growth of the magnetic field. It is shown that the critical H c values fall within the parameter range corresponding to the nontrivial values of the Z 2 topological invariant of the corresponding 1D band Hamiltonian characteristic of the D symmetry class. It is demonstrated that such features in the behavior of the open nanowire are retained even in the presence of Coulomb interactions.
An Exactly Solvable Spin Chain Related to Hahn Polynomials
NASA Astrophysics Data System (ADS)
Stoilova, Neli I.; van der Jeugt, Joris
2011-03-01
We study a linear spin chain which was originally introduced by Shi et al. [Phys. Rev. A 71 (2005), 032309, 5 pages], for which the coupling strength contains a parameter α and depends on the parity of the chain site. Extending the model by a second parameter β, it is shown that the single fermion eigenstates of the Hamiltonian can be computed in explicit form. The components of these eigenvectors turn out to be Hahn polynomials with parameters (α,β) and (α+1,β-1). The construction of the eigenvectors relies on two new difference equations for Hahn polynomials. The explicit knowledge of the eigenstates leads to a closed form expression for the correlation function of the spin chain. We also discuss some aspects of a q-extension of this model.
ℤ3 parafermionic chain emerging from Yang-Baxter equation.
Yu, Li-Wei; Ge, Mo-Lin
2016-02-23
We construct the 1D ℤ3 parafermionic model based on the solution of Yang-Baxter equation and express the model by three types of fermions. It is shown that the ℤ3 parafermionic chain possesses both triple degenerate ground states and non-trivial topological winding number. Hence, the ℤ3 parafermionic model is a direct generalization of 1D ℤ2 Kitaev model. Both the ℤ2 and ℤ3 model can be obtained from Yang-Baxter equation. On the other hand, to show the algebra of parafermionic tripling intuitively, we define a new 3-body Hamiltonian H123 based on Yang-Baxter equation. Different from the Majorana doubling, the H123 holds triple degeneracy at each of energy levels. The triple degeneracy is protected by two symmetry operators of the system, ω-parity P [formula in text] and emergent parafermionic operator Γ, which are the generalizations of parity PM and emergent Majorana operator in Lee-Wilczek model, respectively. Both the ℤ3 parafermionic model and H123 can be viewed as SU(3) models in color space. In comparison with the Majorana models for SU(2), it turns out that the SU(3) models are truly the generalization of Majorana models resultant from Yang-Baxter equation.
The particle spectrum of parity-violating Poincaré gravitational theory
NASA Astrophysics Data System (ADS)
Karananas, Georgios K.
2015-03-01
In this paper we investigate the physical spectrum of the gravitational theory based on the Poincaré group with terms that are at most quadratic in tetrad and spin connection, allowing for the presence of parity-even as well as parity-odd invariants. We determine restrictions on the parameters of the action so that all degrees of freedom propagate and are neither ghosts nor tachyons. We show that the addition of parity non-conserving invariants extends the healthy parameter space of the theory. To accomplish our goal, we apply the weak field approximation around flat spacetime and in order to facilitate the analysis, we separate the bilinear action for the excitations into completely independent spin sectors. For this purpose, we employ the spin-projection operator formalism and extend the original basis built previously, to be able to handle the parity-odd pieces.
Free Fermions and the Classical Compact Groups
NASA Astrophysics Data System (ADS)
Cunden, Fabio Deelan; Mezzadri, Francesco; O'Connell, Neil
2018-06-01
There is a close connection between the ground state of non-interacting fermions in a box with classical (absorbing, reflecting, and periodic) boundary conditions and the eigenvalue statistics of the classical compact groups. The associated determinantal point processes can be extended in two natural directions: (i) we consider the full family of admissible quantum boundary conditions (i.e., self-adjoint extensions) for the Laplacian on a bounded interval, and the corresponding projection correlation kernels; (ii) we construct the grand canonical extensions at finite temperature of the projection kernels, interpolating from Poisson to random matrix eigenvalue statistics. The scaling limits in the bulk and at the edges are studied in a unified framework, and the question of universality is addressed. Whether the finite temperature determinantal processes correspond to the eigenvalue statistics of some matrix models is, a priori, not obvious. We complete the picture by constructing a finite temperature extension of the Haar measure on the classical compact groups. The eigenvalue statistics of the resulting grand canonical matrix models (of random size) corresponds exactly to the grand canonical measure of free fermions with classical boundary conditions.
Deterministic entanglement of superconducting qubits by parity measurement and feedback.
Ristè, D; Dukalski, M; Watson, C A; de Lange, G; Tiggelman, M J; Blanter, Ya M; Lehnert, K W; Schouten, R N; DiCarlo, L
2013-10-17
The stochastic evolution of quantum systems during measurement is arguably the most enigmatic feature of quantum mechanics. Measuring a quantum system typically steers it towards a classical state, destroying the coherence of an initial quantum superposition and the entanglement with other quantum systems. Remarkably, the measurement of a shared property between non-interacting quantum systems can generate entanglement, starting from an uncorrelated state. Of special interest in quantum computing is the parity measurement, which projects the state of multiple qubits (quantum bits) to a state with an even or odd number of excited qubits. A parity meter must discern the two qubit-excitation parities with high fidelity while preserving coherence between same-parity states. Despite numerous proposals for atomic, semiconducting and superconducting qubits, realizing a parity meter that creates entanglement for both even and odd measurement results has remained an outstanding challenge. Here we perform a time-resolved, continuous parity measurement of two superconducting qubits using the cavity in a three-dimensional circuit quantum electrodynamics architecture and phase-sensitive parametric amplification. Using postselection, we produce entanglement by parity measurement reaching 88 per cent fidelity to the closest Bell state. Incorporating the parity meter in a feedback-control loop, we transform the entanglement generation from probabilistic to fully deterministic, achieving 66 per cent fidelity to a target Bell state on demand. These realizations of a parity meter and a feedback-enabled deterministic measurement protocol provide key ingredients for active quantum error correction in the solid state.
Domain wall fermion QCD with the exact one flavor algorithm
Jung, C.; Kelly, C.; Mawhinney, R. D.; ...
2018-03-13
Lattice QCD calculations including the effects of one or more nondegenerate sea quark flavors are conventionally performed using the rational hybrid Monte Carlo (RHMC) algorithm, which computes the square root of the determinant ofmore » $${\\mathcal{D}}^{\\dagger{}}\\mathcal{D}$$, where $$\\mathcal{D}$$ is the Dirac operator. The special case of two degenerate quark flavors with the same mass is described directly by the determinant of $${\\mathcal{D}}^{\\dagger{}}\\mathcal{D}$$—in particular, no square root is necessary—enabling a variety of algorithmic developments, which have driven down the cost of simulating the light (up and down) quarks in the isospin-symmetric limit of equal masses. As a result, the relative cost of single quark flavors—such as the strange or charm—computed with RHMC has become more expensive. This problem is even more severe in the context of our measurements of the $$\\mathrm{{\\Delta}}I=1/2$$ $$K{\\rightarrow}{\\pi}{\\pi}$$ matrix elements on lattice ensembles with $G$-parity boundary conditions, since $G$-parity is associated with a doubling of the number of quark flavors described by $$\\mathcal{D}$$ , and thus RHMC is needed for the isospin-symmetric light quarks as well. In this paper we report on our implementation of the exact one flavor algorithm (EOFA) introduced by the TWQCD Collaboration for simulations including single flavors of domain wall quarks. We have developed a new preconditioner for the EOFA Dirac equation, which both reduces the cost of solving the Dirac equation and allows us to reuse the bulk of our existing high-performance code. Coupling these improvements with careful tuning of our integrator, the time per accepted trajectory in the production of our $2+1$ flavor $G$-parity ensembles with physical pion and kaon masses has been decreased by a factor of 4.2.« less
Domain wall fermion QCD with the exact one flavor algorithm
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jung, C.; Kelly, C.; Mawhinney, R. D.
Lattice QCD calculations including the effects of one or more nondegenerate sea quark flavors are conventionally performed using the rational hybrid Monte Carlo (RHMC) algorithm, which computes the square root of the determinant ofmore » $${\\mathcal{D}}^{\\dagger{}}\\mathcal{D}$$, where $$\\mathcal{D}$$ is the Dirac operator. The special case of two degenerate quark flavors with the same mass is described directly by the determinant of $${\\mathcal{D}}^{\\dagger{}}\\mathcal{D}$$—in particular, no square root is necessary—enabling a variety of algorithmic developments, which have driven down the cost of simulating the light (up and down) quarks in the isospin-symmetric limit of equal masses. As a result, the relative cost of single quark flavors—such as the strange or charm—computed with RHMC has become more expensive. This problem is even more severe in the context of our measurements of the $$\\mathrm{{\\Delta}}I=1/2$$ $$K{\\rightarrow}{\\pi}{\\pi}$$ matrix elements on lattice ensembles with $G$-parity boundary conditions, since $G$-parity is associated with a doubling of the number of quark flavors described by $$\\mathcal{D}$$ , and thus RHMC is needed for the isospin-symmetric light quarks as well. In this paper we report on our implementation of the exact one flavor algorithm (EOFA) introduced by the TWQCD Collaboration for simulations including single flavors of domain wall quarks. We have developed a new preconditioner for the EOFA Dirac equation, which both reduces the cost of solving the Dirac equation and allows us to reuse the bulk of our existing high-performance code. Coupling these improvements with careful tuning of our integrator, the time per accepted trajectory in the production of our $2+1$ flavor $G$-parity ensembles with physical pion and kaon masses has been decreased by a factor of 4.2.« less
Domain wall fermion QCD with the exact one flavor algorithm
NASA Astrophysics Data System (ADS)
Jung, C.; Kelly, C.; Mawhinney, R. D.; Murphy, D. J.
2018-03-01
Lattice QCD calculations including the effects of one or more nondegenerate sea quark flavors are conventionally performed using the rational hybrid Monte Carlo (RHMC) algorithm, which computes the square root of the determinant of D†D , where D is the Dirac operator. The special case of two degenerate quark flavors with the same mass is described directly by the determinant of D†D —in particular, no square root is necessary—enabling a variety of algorithmic developments, which have driven down the cost of simulating the light (up and down) quarks in the isospin-symmetric limit of equal masses. As a result, the relative cost of single quark flavors—such as the strange or charm—computed with RHMC has become more expensive. This problem is even more severe in the context of our measurements of the Δ I =1 /2 K →π π matrix elements on lattice ensembles with G -parity boundary conditions, since G -parity is associated with a doubling of the number of quark flavors described by D , and thus RHMC is needed for the isospin-symmetric light quarks as well. In this paper we report on our implementation of the exact one flavor algorithm (EOFA) introduced by the TWQCD Collaboration for simulations including single flavors of domain wall quarks. We have developed a new preconditioner for the EOFA Dirac equation, which both reduces the cost of solving the Dirac equation and allows us to reuse the bulk of our existing high-performance code. Coupling these improvements with careful tuning of our integrator, the time per accepted trajectory in the production of our 2 +1 flavor G -parity ensembles with physical pion and kaon masses has been decreased by a factor of 4.2.
Quark flavour observables in the Littlest Higgs model with T-parity after LHC Run 1.
Blanke, Monika; Buras, Andrzej J; Recksiegel, Stefan
2016-01-01
The Littlest Higgs model with T-parity (LHT) belongs to the simplest new physics scenarios with new sources of flavour and CP violation. The latter originate in the interactions of ordinary quarks and leptons with heavy mirror quarks and leptons that are mediated by new heavy gauge bosons. Also a heavy fermionic top partner is present in this model which communicates with the SM fermions by means of standard [Formula: see text] and [Formula: see text] gauge bosons. We present a new analysis of quark flavour observables in the LHT model in view of the oncoming flavour precision era. We use all available information on the CKM parameters, lattice QCD input and experimental data on quark flavour observables and corresponding theoretical calculations, taking into account new lower bounds on the symmetry breaking scale and the mirror quark masses from the LHC. We investigate by how much the branching ratios for a number of rare K and B decays are still allowed to depart from their SM values. This includes [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]. Taking into account the constraints from [Formula: see text] processes, significant departures from the SM predictions for [Formula: see text] and [Formula: see text] are possible, while the effects in B decays are much smaller. In particular, the LHT model favours [Formula: see text], which is not supported by the data, and the present anomalies in [Formula: see text] decays cannot be explained in this model. With the recent lattice and large N input the imposition of the [Formula: see text] constraint implies a significant suppression of the branching ratio for [Formula: see text] with respect to its SM value while allowing only for small modifications of [Formula: see text]. Finally, we investigate how the LHT physics could be distinguished from other models by means of indirect measurements and discuss the consequences for quark flavour observables of not finding any LHT state in the coming years.
DOE Office of Scientific and Technical Information (OSTI.GOV)
MCCLEAN, JARROD; HANER, THOMAS; STEIGER, DAMIAN
FermiLib is an open source software package designed to facilitate the development and testing of algorithms for simulations of fermionic systems on quantum computers. Fermionic simulations represent an important application of early quantum devices with a lot of potential high value targets, such as quantum chemistry for the development of new catalysts. This software strives to provide a link between the required domain expertise in specific fermionic applications and quantum computing to enable more users to directly interface with, and develop for, these applications. It is an extensible Python library designed to interface with the high performance quantum simulator, ProjectQ,more » as well as application specific software such as PSI4 from the domain of quantum chemistry. Such software is key to enabling effective user facilities in quantum computation research.« less
High-pressure studies on heavy fermion systems
NASA Astrophysics Data System (ADS)
Ye, Chen; Zongfa, Weng; Smidman, Michael; Xin, Lu; Huiqiu, Yuan
2016-07-01
In this review article, we give a brief overview of heavy fermions, which are prototype examples of strongly correlated electron systems. We introduce the application of physical pressure in heavy fermion systems to construct their pressure phase diagrams and to study the close relationship between superconductivity (SC) and other electronic instabilities, such as antiferromagnetism (AFM), ferromagnetism (FM), and valence transitions. Field-angle dependent heat capacity and point-contact spectroscopic measurements under pressure are taken as examples to illustrate their ability to investigate novel physical properties of the emergent electronic states. Project supported by the National Basic Research Program of China (Grant No. 2011CBA00103), the National Natural Science Foundation of China (Grant Nos. 11174245 and 11374257), the Science Challenge Program of China, and the Fundamental Research Funds for the Central Universities of China.
Structure of sup 118 Sb nucleus
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gulyas, J.; Fenyes, T.; Fayez, M.
1992-10-01
{gamma}, {gamma}{gamma}-coincidence, internal conversion electron, and {gamma}-ray angular distribution spectra of the {sup 118}Sn({ital p},{ital n}{gamma}){sup 118}Sb reaction were measured at different bombarding proton energies between 5.5 and 7.5 MeV. {gamma}, {gamma}{gamma}-coincidence, and internal conversion electron spectra of the {sup 115}In ({alpha},{ital n}{gamma}){sup 118}Sb reaction were also measured at {ital E}{sub {alpha}}=14.5 MeV. Ge(HP), Ge(Li), Ge(LEPS) {gamma}-ray detectors, as well as a superconducting magnetic lens electron spectrometer (with Si(Li) detectors), were used in the experiments. About 210 (including {similar to}130 new) {gamma} rays have been assigned to {sup 118}Sb. The deduced {sup 118}Sb level scheme contains more than 70 newmore » levels. On the basis of the internal conversion coefficients, Hauser-Feshbach analysis of ({ital p},{ital n}) reaction cross sections, {gamma}-ray angular distributions, and other arguments spin and parity values have been determined. The parabolic rule'' prediction of the energy splitting of different proton-neutron multiplets enabled the identification of many proton-neutron multiplet states. The energy spectrum and electromagnetic properties have been calculated in the framework of the interacting boson-fermion-fermion--odd-odd truncated quadrupole phonon model, and reasonably good agreement has been obtained between experimental and theoretical results.« less
Nodal gap structure and order parameter symmetry of the unconventional superconductor UPt₃
Gannon, W. J.; Halperin, W. P.; Rastovski, C.; ...
2015-02-01
Spanning a broad range of physical systems, complex symmetry breaking is widely recognized as a hallmark of competing interactions. This is exemplified in superfluid ³He which has multiple thermodynamic phases with spin and orbital quantum numbers S = 1 and L = 1, that emerge on cooling from a nearly ferromagnetic Fermi liquid. The heavy fermion compound UPt₃ exhibits similar behavior clearly manifest in its multiple superconducting phases. However, consensus as to its order parameter symmetry has remained elusive. Our small angle neutron scattering measurements indicate a linear temperature dependence of the London penetration depth characteristic of nodal structure ofmore » the order parameter. Our theoretical analysis is consistent with assignment of its symmetry to an L = 3 odd parity state for which one of the three thermodynamic phases in non-zero magnetic field is chiral.« less
Nodal gap structure and order parameter symmetry of the unconventional superconductor UPt₃
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gannon, W. J.; Halperin, W. P.; Rastovski, C.
Spanning a broad range of physical systems, complex symmetry breaking is widely recognized as a hallmark of competing interactions. This is exemplified in superfluid ³He which has multiple thermodynamic phases with spin and orbital quantum numbers S = 1 and L = 1, that emerge on cooling from a nearly ferromagnetic Fermi liquid. The heavy fermion compound UPt₃ exhibits similar behavior clearly manifest in its multiple superconducting phases. However, consensus as to its order parameter symmetry has remained elusive. Our small angle neutron scattering measurements indicate a linear temperature dependence of the London penetration depth characteristic of nodal structure ofmore » the order parameter. Our theoretical analysis is consistent with assignment of its symmetry to an L = 3 odd parity state for which one of the three thermodynamic phases in non-zero magnetic field is chiral.« less
Constraints on models for the Higgs boson with exotic spin and parity
NASA Astrophysics Data System (ADS)
Johnson, Emily Hannah
The production of a Higgs boson in association with a vector boson at the Tevatron offers a unique opportunity to study models for the Higgs boson with exotic spin J and parity P assignments. At the Tevatron the V H system is produced near threshold. Different JP assignments of the Higgs boson can be distinguished by examining the behavior of the cross section near threshold. The relatively low backgrounds at the Tevatron compared to the LHC put us in a unique position to study the direct decay of the Higgs boson to fermions. If the Higgs sector is more complex than predicted, studying the spin and parity of the Higgs boson in all decay modes is important. In this Thesis we will examine the WH → lnu bb¯ production and decay mode using 9.7 fb-1 of data collected by the D0 experiment in an attempt to derive constraints on models containing exotic values for the spin and parity of the Higgs boson. In particular, we will examine models for a Higgs boson with J P = 0- and JP = 2+. We use a likelihood ratio to quantify the degree to which our data are incompatible with exotic JP predictions for a range of possible production rates. Assuming the production cross section times branching ratio of the signals in the models considered is equal to the standard model prediction, the WH → lnu bb¯ mode alone is unable to reject either exotic model considered. We will also discuss the combination of the ZH → llbb¯, WH → lnubb¯, and V H → nunu bb¯ production modes at the D0 experiment and with the CDF experiment. When combining all three production modes at the D0 experiment we reject the JP = 0- and J P = 2+ hypotheses at the 97.6% CL and at the 99.0% CL, respectively, when assuming the signal production cross section times branching ratio is equal to the standard model predicted value. When combining with the CDF experiment we reject the JP = 0- and JP = 2 + hypotheses with significances of 5.0 standard deviations and 4.9 standard deviations, respectively.
Federal Parity In The Evolving Mental Health And Addiction Care Landscape.
Barry, Colleen L; Goldman, Howard H; Huskamp, Haiden A
2016-06-01
The intent of the Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008 is to eliminate differences between health insurance coverage of mental health and substance use disorder benefits and coverage of medical or surgical benefits. The Affordable Care Act significantly extended the reach of the Wellstone-Domenici law by applying it to new insurance markets. We summarize the evolution of legislative and regulatory actions to bring about federal insurance parity. We also summarize available evidence on how the Wellstone-Domenici law has contributed to addressing insurance discrimination; rectifying market inefficiencies due to adverse selection; and altering utilization, spending, and health outcomes for people with mental health and substance use disorders. In addition, we highlight important gaps in knowledge about how parity has been implemented, describe the groups still lacking parity-level coverage, and make recommendations on steps to improve the likelihood that the Wellstone-Domenici law will fulfill the aims of its architects. Project HOPE—The People-to-People Health Foundation, Inc.
Grid-Parity Solar Power for Department of Defense Installations
2014-02-01
MW DC. Installed capacity of panels. Capacity of 1 MW DC. Capacity = 998.4 kWp DC. Photovoltaic Peak Capacity ( Power Delivered). PVSyst... Photovoltaic Annual Output ( Power Delivered) The power delivered to Camp Roberts should match or exceed results simulated using the University of Geneva...FINAL REPORT Grid-Parity Solar Power for Department of Defense Installations ESTCP Project EW-201134 FEBRUARY 2014 John Bender
Continuously monitoring the parity of superconducting qubits in a 2D cQED architecture
NASA Astrophysics Data System (ADS)
Blok, Machiel; Flurin, Emmanuel; Livingston, William; Colless, James; Dove, Allison; Siddiqi, Irfan
Continuous measurements of joint qubit properties such as their parity can reveal insight into the collapse dynamics of entangled states and are a prerequisite for implementing continuous quantum error correction. Here it is crucial that the measurement collects no information other than the parity to avoid measurement induced dephasing. In a cQED architecture, a full-parity measurement can be implemented by strongly coupling two transmon qubits to a single high-Q planar resonator (χ >> κ). We will discuss the experimental implementation of this on-chip technique and the prospects to extend it to more qubits. This will allow us to monitor, in real-time, the projection into multi-partite entangled states and continuously detect errors on a logical qubit encoded in an entangled subspace. This work was supported by Army Research Office.
Localization enhanced and degraded topological order in interacting p -wave wires
NASA Astrophysics Data System (ADS)
Kells, G.; Moran, N.; Meidan, D.
2018-02-01
We numerically study the effect of disorder on the stability of the many-body zero mode in a Kitaev chain with local interactions. Our numerical procedure allows us to resolve the position space and multiparticle structure of the zero modes, as well as providing estimates for the mean energy splitting between pairs of states of opposite fermion parity, over the full many-body spectrum. We find that the parameter space of a clean system can be divided into regions where interaction induced decay transitions are suppressed (region I) and where they are not (region II). In region I we observe that disorder has an adverse effect on the zero mode, which extends further into the bulk and is accompanied by an increased energy splitting between pairs of states of opposite parity. Conversely region II sees a more intricate effect of disorder, showing an enhancement of localization at the system's end accompanied by a reduction in the mean pairwise energy splitting. We discuss our results in the context of the many-body localization (MBL). We show that while the mechanism that drives the MBL transition also contributes to the fock-space localization of the many-body zero modes, measures that characterize the degree of MBL do not necessarily correlate with an enhancement of the zero mode or an improved stability of the topological region.
Projected Shell Model Description of Positive Parity Band of 130Pr Nucleus
NASA Astrophysics Data System (ADS)
Singh, Suram; Kumar, Amit; Singh, Dhanvir; Sharma, Chetan; Bharti, Arun; Bhat, G. H.; Sheikh, J. A.
2018-02-01
Theoretical investigation of positive parity yrast band of odd-odd 130Pr nucleus is performed by applying the projected shell model. The present study is undertaken to investigate and verify the very recently observed side band in 130Pr theoretically in terms of quasi-particle (qp) configuration. From the analysis of band diagram, the yrast as well as side band are found to arise from two-qp configuration πh 11/2 ⊗ νh 11/2. The present calculations are viewed to have qualitatively reproduced the known experimental data for yrast states, transition energies, and B( M1) / B( E2) ratios of this nucleus. The recently observed positive parity side band is also reproduced by the present calculations. The energy states of the side band are predicted up to spin 25+, which is far above the known experimental spin of 18+ and this could serve as a motivational factor for future experiments. In addition, the reduced transition probability B( E2) for interband transitions has also been calculated for the first time in projected shell model, which would serve as an encouragement for other research groups in the future.
Raman spectroscopy of magneto-phonon resonances in graphene and graphite
NASA Astrophysics Data System (ADS)
Goler, Sarah; Yan, Jun; Pellegrini, Vittorio; Pinczuk, Aron
2012-08-01
The magneto-phonon resonance or MPR occurs in semiconductor materials when the energy spacing between Landau levels is continuously tuned to cross the energy of an optical phonon mode. MPRs have been largely explored in bulk semiconductors, in two-dimensional systems and in quantum dots. Recently there has been significant interest in the MPR interactions of the Dirac fermion magneto-excitons in graphene, and a rich splitting and anti-crossing phenomena of the even parity E2g long wavelength optical phonon mode have been theoretically proposed and experimentally observed. The MPR has been found to crucially depend on disorder in the graphene layer. This is a feature that creates new venues for the study of interplays between disorder and interactions in the atomic layers. We review here the fundamentals of MRP in graphene and the experimental Raman scattering works that have led to the observation of these phenomena in graphene and graphite.
Photonic zero mode in a non-Hermitian photonic lattice.
Pan, Mingsen; Zhao, Han; Miao, Pei; Longhi, Stefano; Feng, Liang
2018-04-03
Zero-energy particles (such as Majorana fermions) are newly predicted quasiparticles and are expected to play an important role in fault-tolerant quantum computation. In conventional Hermitian quantum systems, however, such zero states are vulnerable and even become vanishing if couplings with surroundings are of the same topological nature. Here we demonstrate a robust photonic zero mode sustained by a spatial non-Hermitian phase transition in a parity-time (PT) symmetric lattice, despite the same topological order across the entire system. The non-Hermitian-enhanced topological protection ensures the reemergence of the zero mode at the phase transition interface when the two semi-lattices under different PT phases are decoupled effectively in their real spectra. Residing at the midgap level of the PT symmetric spectrum, the zero mode is topologically protected against topological disorder. We experimentally validated the robustness of the zero-energy mode by ultrafast heterodyne measurements of light transport dynamics in a silicon waveguide lattice.
Representation of radiative strength functions within a practical model of cascade gamma decay
DOE Office of Scientific and Technical Information (OSTI.GOV)
Vu, D. C., E-mail: vuconghnue@gmail.com; Sukhovoj, A. M., E-mail: suchovoj@nf.jinr.ru; Mitsyna, L. V., E-mail: mitsyna@nf.jinr.ru
A practical model developed at the Joint Institute for Nuclear Research (JINR, Dubna) in order to describe the cascade gamma decay of neutron resonances makes it possible to determine simultaneously, from an approximation of the intensities of two-step cascades, parameters of nuclear level densities and partial widths with respect to the emission of nuclear-reaction products. The number of the phenomenological ideas used isminimized in themodel version considered in the present study. An analysis of new results confirms what was obtained earlier for the dependence of dynamics of the interaction of fermion and boson nuclear states on the nuclear shape. Frommore » the ratio of the level densities for excitations of the vibrational and quasiparticle types, it also follows that this interaction manifests itself in the region around the neutron binding energy and is probably different in nuclei that have different parities of nucleons.« less
Band and Correlated Insulators of Cold Fermions in a Mesoscopic Lattice
NASA Astrophysics Data System (ADS)
Lebrat, Martin; Grišins, Pjotrs; Husmann, Dominik; Häusler, Samuel; Corman, Laura; Giamarchi, Thierry; Brantut, Jean-Philippe; Esslinger, Tilman
2018-01-01
We investigate the transport properties of neutral, fermionic atoms passing through a one-dimensional quantum wire containing a mesoscopic lattice. The lattice is realized by projecting individually controlled, thin optical barriers on top of a ballistic conductor. Building an increasingly longer lattice, one site after another, we observe and characterize the emergence of a band insulating phase, demonstrating control over quantum-coherent transport. We explore the influence of atom-atom interactions and show that the insulating state persists as contact interactions are tuned from moderately to strongly attractive. Using bosonization and classical Monte Carlo simulations, we analyze such a model of interacting fermions and find good qualitative agreement with the data. The robustness of the insulating state supports the existence of a Luther-Emery liquid in the one-dimensional wire. Our work realizes a tunable, site-controlled lattice Fermi gas strongly coupled to reservoirs, which is an ideal test bed for nonequilibrium many-body physics.
Fermionic spin liquid analysis of the paramagnetic state in volborthite
NASA Astrophysics Data System (ADS)
Chern, Li Ern; Schaffer, Robert; Sorn, Sopheak; Kim, Yong Baek
2017-10-01
Recently, thermal Hall effect has been observed in the paramagnetic state of volborthite, which consists of distorted kagome layers with S =1 /2 local moments. Despite the appearance of magnetic order below 1 K , the response to external magnetic field and unusual properties of the paramagnetic state above 1 K suggest possible realization of exotic quantum phases. Motivated by these discoveries, we investigate possible spin liquid phases with fermionic spinon excitations in a nonsymmorphic version of the kagome lattice, which belongs to the two-dimensional crystallographic group p 2 g g . This nonsymmorphic structure is consistent with the spin model obtained in the density functional theory calculation. Using projective symmetry group analysis and fermionic parton mean field theory, we identify twelve distinct Z2 spin liquid states, four of which are found to have correspondence in the eight Schwinger boson spin liquid states we classified earlier. We focus on the four fermionic states with bosonic counterpart and find that the spectrum of their corresponding root U (1 ) states features spinon Fermi surface. The existence of spinon Fermi surface in candidate spin liquid states may offer a possible explanation of the finite thermal Hall conductivity observed in volborthite.
NASA Astrophysics Data System (ADS)
Nori, Franco
2014-03-01
We study a heterostructure which consists of a topological insulator and a superconductor with a hole. This system supports a robust Majorana fermion state bound to the vortex core. We study the possibility of using scanning tunneling spectroscopy (i) to detect the Majorana fermion in this setup and (ii) to study excited states bound to the vortex core. The Majorana fermion manifests itself as an H-dependent zero-bias anomaly of the tunneling conductance. The excited states spectrum differs from the spectrum of a typical Abrikosov vortex, providing additional indirect confirmation of the Majorana state observation. We also study how to manipulate and probe Majorana fermions using super-conducting circuits. In we consider a semiconductor nanowire quantum dot with strong spin-orbit coupling (SOC), which can be used to achieve a spin-orbit qubit. In contrast to a spin qubit, the spin-orbit qubit can respond to an external ac electric field, i.e., electric-dipole spin resonance. We develop a theory that can apply in the strong SOC regime. We find that there is an optimal SOC strength ηopt = √ 2/2, where the Rabi frequency induced by the ac electric field becomes maximal. Also, we show that both the level spacing and the Rabi frequency of the spin-orbit qubit have periodic responses to the direction of the external static magnetic field. These responses can be used to determine the SOC in the nanowire. FN is partly supported by the RIKEN CEMS, iTHES Project, MURI Center for Dynamic Magneto-Optics, JSPS-RFBR Contract No. 12-02-92100, Grant-in-Aid for Scientific Research (S), MEXT Kakenhi on Quantum Cybernetics, and the JSPS via its FIRST program.
Projected Entangled Pair States with non-Abelian gauge symmetries: An SU(2) study
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zohar, Erez, E-mail: erez.zohar@mpq.mpg.de; Wahl, Thorsten B.; Burrello, Michele, E-mail: michele.burrello@mpq.mpg.de
Over the last years, Projected Entangled Pair States have demonstrated great power for the study of many body systems, as they naturally describe ground states of gapped many body Hamiltonians, and suggest a constructive way to encode and classify their symmetries. The PEPS study is not only limited to global symmetries, but has also been extended and applied for local symmetries, allowing to use them for the description of states in lattice gauge theories. In this paper we discuss PEPS with a local, SU(2) gauge symmetry, and demonstrate the use of PEPS features and techniques for the study of amore » simple family of many body states with a non-Abelian gauge symmetry. We present, in particular, the construction of fermionic PEPS able to describe both two-color fermionic matter and the degrees of freedom of an SU(2) gauge field with a suitable truncation.« less
Global constraints on Z2 fluxes in two different anisotropic limits of a hypernonagon Kitaev model
NASA Astrophysics Data System (ADS)
Kato, Yasuyuki; Kamiya, Yoshitomo; Nasu, Joji; Motome, Yukitoshi
2018-05-01
The Kitaev model is an exactly-soluble quantum spin model, whose ground state provides a canonical example of a quantum spin liquid. Spin excitations from the ground state are fractionalized into emergent matter fermions and Z2 fluxes. The Z2 flux excitation is pointlike in two dimensions, while it comprises a closed loop in three dimensions because of the local constraint for each closed volume. In addition, the fluxes obey global constraints involving (semi)macroscopic number of fluxes. We here investigate such global constraints in the Kitaev model on a three-dimensional lattice composed of nine-site elementary loops, dubbed the hypernonagon lattice, whose ground state is a chiral spin liquid. We consider two different anisotropic limits of the hypernonagon Kitaev model where the low-energy effective models are described solely by the Z2 fluxes. We show that there are two kinds of global constraints in the model defined on a three-dimensional torus, namely, surface and volume constraints: the surface constraint is imposed on the even-odd parity of the total number of fluxes threading a two-dimensional slice of the system, while the volume constraint is for the even-odd parity of the number of the fluxes through specific plaquettes whose total number is proportional to the system volume. In the two anisotropic limits, therefore, the elementary excitation of Z2 fluxes occurs in a pair of closed loops so as to satisfy both two global constraints as well as the local constraints.
Constraints on Models for the Higgs Boson with Exotic Spin and Parity
DOE Office of Scientific and Technical Information (OSTI.GOV)
Johnson, Emily Hannah
The production of a Higgs boson in association with a vector boson at the Tevatron offers a unique opportunity to study models for the Higgs boson with exotic spin J and parity P assignments. At the Tevatron the V H system is produced near threshold. Different JP assignments of the Higgs boson can be distinguished by examining the behavior of the cross section near threshold. The relatively low backgrounds at the Tevatron compared to the LHC put us in a unique position to study the direct decay of the Higgs boson to fermions. If the Higgs sector is more complexmore » than predicted, studying the spin and parity of the Higgs boson in all decay modes is important. In this Thesis we will examine the WH → ℓνb¯b production and decay mode using 9.7 fb -1 of data collected by the D0 experiment in an attempt to derive constraints on models containing exotic values for the spin and parity of the Higgs boson. In particular, we will examine models for a Higgs boson with JP = 0- and JP = 2+. We use a likelihood ratio to quantify the degree to which our data are incompatible with exotic JP predictions for a range of possible production rates. Assuming the production cross section times branching ratio of the signals in the models considered is equal to the standard model prediction, the WH → ℓνb¯b mode alone is unable to reject either exotic model considered. We will also discuss the combination of the ZH → ℓℓb¯b, WH → ℓνb¯b, and V H → ννb¯b production modes at the D0 experiment and with the CDF experiment. When combining all three production modes at the D0 experiment we reject the JP = 0- and JP = 2+ hypotheses at the 97.6% CL and at the 99.0% CL, respectively, when assuming the signal production cross section times branching ratio is equal to the standard model predicted value. When combining with the CDF experiment we reject the JP = 0- and JP = 2+ hypotheses with significances of 5.0 standard deviations and 4.9 standard deviations, respectively.abstract« less
Precision measurement of the weak charge of the proton.
2018-05-01
Large experimental programmes in the fields of nuclear and particle physics search for evidence of physics beyond that explained by current theories. The observation of the Higgs boson completed the set of particles predicted by the standard model, which currently provides the best description of fundamental particles and forces. However, this theory's limitations include a failure to predict fundamental parameters, such as the mass of the Higgs boson, and the inability to account for dark matter and energy, gravity, and the matter-antimatter asymmetry in the Universe, among other phenomena. These limitations have inspired searches for physics beyond the standard model in the post-Higgs era through the direct production of additional particles at high-energy accelerators, which have so far been unsuccessful. Examples include searches for supersymmetric particles, which connect bosons (integer-spin particles) with fermions (half-integer-spin particles), and for leptoquarks, which mix the fundamental quarks with leptons. Alternatively, indirect searches using precise measurements of well predicted standard-model observables allow highly targeted alternative tests for physics beyond the standard model because they can reach mass and energy scales beyond those directly accessible by today's high-energy accelerators. Such an indirect search aims to determine the weak charge of the proton, which defines the strength of the proton's interaction with other particles via the well known neutral electroweak force. Because parity symmetry (invariance under the spatial inversion (x, y, z) → (-x, -y, -z)) is violated only in the weak interaction, it provides a tool with which to isolate the weak interaction and thus to measure the proton's weak charge 1 . Here we report the value 0.0719 ± 0.0045, where the uncertainty is one standard deviation, derived from our measured parity-violating asymmetry in the scattering of polarized electrons on protons, which is -226.5 ± 9.3 parts per billion (the uncertainty is one standard deviation). Our value for the proton's weak charge is in excellent agreement with the standard model 2 and sets multi-teraelectronvolt-scale constraints on any semi-leptonic parity-violating physics not described within the standard model. Our results show that precision parity-violating measurements enable searches for physics beyond the standard model that can compete with direct searches at high-energy accelerators and, together with astronomical observations, can provide fertile approaches to probing higher mass scales.
Multigrid for Staggered Lattice Fermions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brower, Richard C.; Clark, M. A.; Strelchenko, Alexei
Critical slowing down in Krylov methods for the Dirac operator presents a major obstacle to further advances in lattice field theory as it approaches the continuum solution. Here we formulate a multi-grid algorithm for the Kogut-Susskind (or staggered) fermion discretization which has proven difficult relative to Wilson multigrid due to its first-order anti-Hermitian structure. The solution is to introduce a novel spectral transformation by the K\\"ahler-Dirac spin structure prior to the Galerkin projection. We present numerical results for the two-dimensional, two-flavor Schwinger model, however, the general formalism is agnostic to dimension and is directly applicable to four-dimensional lattice QCD.
Broecker, Peter; Trebst, Simon
2016-12-01
In the absence of a fermion sign problem, auxiliary-field (or determinantal) quantum Monte Carlo (DQMC) approaches have long been the numerical method of choice for unbiased, large-scale simulations of interacting many-fermion systems. More recently, the conceptual scope of this approach has been expanded by introducing ingenious schemes to compute entanglement entropies within its framework. On a practical level, these approaches, however, suffer from a variety of numerical instabilities that have largely impeded their applicability. Here we report on a number of algorithmic advances to overcome many of these numerical instabilities and significantly improve the calculation of entanglement measures in the zero-temperature projective DQMC approach, ultimately allowing us to reach similar system sizes as for the computation of conventional observables. We demonstrate the applicability of this improved DQMC approach by providing an entanglement perspective on the quantum phase transition from a magnetically ordered Mott insulator to a band insulator in the bilayer square lattice Hubbard model at half filling.
Fermionic entanglement in superconducting systems
NASA Astrophysics Data System (ADS)
Di Tullio, M.; Gigena, N.; Rossignoli, R.
2018-06-01
We examine distinct measures of fermionic entanglement in the exact ground state of a finite superconducting system. It is first shown that global measures such as the one-body entanglement entropy, which represents the minimum relative entropy between the exact ground state and the set of fermionic Gaussian states, exhibit a close correlation with the BCS gap, saturating in the strong superconducting regime. The same behavior is displayed by the bipartite entanglement between the set of all single-particle states k of positive quasimomenta and their time-reversed partners k ¯. In contrast, the entanglement associated with the reduced density matrix of four single-particle modes k ,k ¯ , k',k¯' , which can be measured through a properly defined fermionic concurrence, exhibits a different behavior, showing a peak in the vicinity of the superconducting transition for states k ,k' close to the Fermi level and becoming small in the strong coupling regime. In the latter, such reduced state exhibits, instead, a finite mutual information and quantum discord. While the first measures can be correctly estimated with the BCS approximation, the previous four-level concurrence lies strictly beyond the latter, requiring at least a particle-number projected BCS treatment for its description. Formal properties of all previous entanglement measures are as well discussed.
NASA Astrophysics Data System (ADS)
de Carvalho, Vanuildo S.; Kloss, Thomas; Montiel, Xavier; Freire, Hermann; Pépin, Catherine
2015-08-01
We study the fate of the so-called ΘI I-loop-current order that breaks both time-reversal and parity symmetries in a two-dimensional hot spot model with antiferromagnetically mediated interactions, using Fermi surfaces relevant to the phenomenology of the cuprate superconductors. We start from a three-band Emery model describing the hopping of holes in the CuO2 plane that includes two hopping parameters tp p and tp d, local onsite Coulomb interactions Ud and Up, and nearest-neighbor Vp d couplings between the fermions in the copper [Cu (3 dx2-y2) ] and oxygen [O (2 px) and O (2 py)] orbitals. By focusing on the lowest-energy band, we proceed to decouple the local interaction Ud of the Cu orbital in the spin channel using a Hubbard-Stratonovich transformation to arrive at the interacting part of the so-called spin-fermion model. We also decouple the nearest-neighbor interaction Vp d to introduce the order parameter of the ΘI I-loop-current order. In this way, we are able to construct a consistent mean-field theory that describes the strong competition between the composite order parameter made of a quadrupole-density wave and d -wave pairing fluctuations proposed in Efetov et al. [Nat. Phys. 9, 442 (2013), 10.1038/nphys2641] with the ΘI I-loop-current order parameter that is argued to be relevant for explaining important aspects of the physics of the pseudogap phase displayed in the underdoped cuprates.
Aspects Topologiques de la Theorie des Champs et leurs Applications
NASA Astrophysics Data System (ADS)
Caenepeel, Didier
This thesis is dedicated to the study of various topological aspects of field theory, and is divided in three parts. In two space dimensions the possibility of fractional statistics can be implemented by adding an appropriate "fictitious" electric charge and magnetic flux to each particle (after which they are known as anyons). Since the statistical interaction is rather difficult to handle, a mean-field approximation is used in order to describe a gas of anyons. We derive a criterion for the validity of this approximation using the inherent feature of parity violation in the scattering of anyons. We use this new method in various examples of anyons and show both analytically and numerically that the approximation is justified if the statistical interaction is weak, and that it must be more weak for boson-based than for fermion-based anyons. Chern-Simons theories give an elegant implementation of anyonic properties in field theories, which permits the emergence of new mechanisms for anyon superconductivity. Since it is reasonable to think that superconductivity is a low energy phenomenon, we have been interested in non-relativistic C-S systems. We present the scalar field effective potential for non-relativistic matter coupled to both Abelian and non-Abelian C-S gauge fields. We perform the calculations using functional methods in background fields. Finally, we compute the scalar effective potential in various gauges and treat divergences with various regularization schemes. In three space dimensions, a generalization of Chern-Simons theory may be achieved by introducing an antisymmetric tensor gauge field. We use these theories, called B wedge F theories, to present an alternative to the Higgs mechanism to generate masses for non-Abelian gauge fields. The initial Lagrangian is composed of a fermion with current-current and dipole-dipole type self -interactions minimally coupled to non-Abelian gauge fields. The mass generation occurs upon the fermionic functional integration. We show that by suitably adjusting the coupling constants the effective theory contains massive non-Abelian gauge fields without any residual scalars or other degrees of freedom.
Lattice calculation of electric dipole moments and form factors of the nucleon
NASA Astrophysics Data System (ADS)
Abramczyk, M.; Aoki, S.; Blum, T.; Izubuchi, T.; Ohki, H.; Syritsyn, S.
2017-07-01
We analyze commonly used expressions for computing the nucleon electric dipole form factors (EDFF) F3 and moments (EDM) on a lattice and find that they lead to spurious contributions from the Pauli form factor F2 due to inadequate definition of these form factors when parity mixing of lattice nucleon fields is involved. Using chirally symmetric domain wall fermions, we calculate the proton and the neutron EDFF induced by the C P -violating quark chromo-EDM interaction using the corrected expression. In addition, we calculate the electric dipole moment of the neutron using a background electric field that respects time translation invariance and boundary conditions, and we find that it decidedly agrees with the new formula but not the old formula for F3. Finally, we analyze some selected lattice results for the nucleon EDM and observe that after the correction is applied, they either agree with zero or are substantially reduced in magnitude, thus reconciling their difference from phenomenological estimates of the nucleon EDM.
Roper resonance and S11(1535) from lattice QCD
DOE Office of Scientific and Technical Information (OSTI.GOV)
N. Mathur; Y. Chen; S.J. Dong
2005-01-06
Using the constrained curve fitting method and overlap fermions with the lowest pion mass at 180 MeV, we observe that the masses of the first positive and negative parity excited states of the nucleon tend to cross over as the quark masses are taken to the chiral limit. Both results at the physical pion mass agree with the experimental values of the Roper resonance (N{sup 1/2+} (1440)) and S{sub 11} (N{sup 1/2-}(1535)). This is seen for the first time in a lattice QCD calculation. These results are obtained on a quenched Iwasaki 16{sup 3} x 28 lattice with a =more » 0.2 fm. We also extract the ghost {eta}{prime} N states (a quenched artifact) which are shown to decouple from the nucleon interpolation field above m{sub {pi}} {approx} 300 MeV. From the quark mass dependence of these states in the chiral region, we conclude that spontaneously broken chiral symmetry dictates the dynamics of light quarks in the nucleon.« less
Koch, E; Bogado, M; Araya, F; Romero, T; Díaz, C; Manriquez, L; Paredes, M; Román, C; Taylor, A; Kirschbaum, A
2008-05-01
To find out whether there is an association between parity and obesity, evaluated through body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) in Chilean women after controlling for sociodemographic characteristics, health risk and gynaeco-obstetric factors. Cross-sectional study, using baseline data of the San Francisco Project. San Francisco de Mostazal, located in the central region of Chile, 6512 Chilean-Hispanic women (Spanish heritage with a variable indigenous component). A weighted random sample of 508 women who had their first pregnancy inside the primary child-bearing ages. Data were collected between 1997 and 1999. Statistical associations between parity and different anthropometric measurements of adiposity in multiple linear (MLnR) and logistic regression models (MLtR) were evaluated. In MLnR a modest parity-related increment in BMI and practically null increment in WC, WHR and WHtR was observed. Covariates that showed a statistically significant association with anthropometric measures of adiposity were age, low education, marital status, employment, smoking, smoking cessation, hypertension, diabetes, dyslipidaemia, parent's obesity, menarche and fetal macrosomia. Crude odds ratio (OR) showed a strong association between parity and anthropometric markers of obesity. Nevertheless, after adjustments in MLtR models, the association remained only for BMI. All the measures of abdominal obesity related to parous women showed OR smaller than 1 (95% confidence intervals 0.57 to 0.96). Parity modestly influences BMI, but does not seem to be related to WC, WHR and WHtR after controlling by confounders. Parity can increase adiposity but not necessarily following an abdominal pattern.
Qubit and fermionic Fock spaces from type II superstring black holes
NASA Astrophysics Data System (ADS)
Belhaj, A.; Bensed, M.; Benslimane, Z.; Sedra, M. B.; Segui, A.
Using Hodge diagram combinatorial data, we study qubit and fermionic Fock spaces from the point of view of type II superstring black holes based on complex compactifications. Concretely, we establish a one-to-one correspondence between qubits, fermionic spaces and extremal black holes in maximally supersymmetric supergravity obtained from type II superstring on complex toroidal and Calabi-Yau compactifications. We interpret the differential forms of the n-dimensional complex toroidal compactification as states of n-qubits encoding information on extremal black hole charges. We show that there are 2n copies of n qubit systems which can be split as 2n = 2n-1 + 2n-1. More precisely, 2n-1 copies are associated with even D-brane charges in type IIA superstring and the other 2n-1 ones correspond to odd D-brane charges in IIB superstring. This correspondence is generalized to a class of Calabi-Yau manifolds. In connection with black hole charges in type IIA superstring, an n-qubit system has been obtained from a canonical line bundle of n factors of one-dimensional projective space ℂℙ1.
Composite fermion basis for two-component Bose gases
NASA Astrophysics Data System (ADS)
Meyer, Marius; Liabotro, Ola
The composite fermion (CF) construction is known to produce wave functions that are not necessarily orthogonal, or even linearly independent, after projection. While usually not a practical issue in the quantum Hall regime, we have previously shown that it presents a technical challenge for rotating Bose gases with low angular momentum. These are systems where the CF approach yield surprisingly good approximations to the exact eigenstates of weak short-range interactions, and so solving the problem of linearly dependent wave functions is of interest. It can also be useful for studying CF excitations for fermions. Here we present several ways of constructing a basis for the space of ``simple CF states'' for two-component rotating Bose gases in the lowest Landau level, and prove that they all give a basis. Using the basis, we study the structure of the lowest-lying state using so-called restricted wave functions. We also examine the scaling of the overlap between the exact and CF wave functions at the maximal possible angular momentum for simple states. This work was financially supported by the Research Council of Norway.
Phase coherent transport in hybrid superconductor-topological insulator devices
NASA Astrophysics Data System (ADS)
Finck, Aaron
2015-03-01
Heterostructures of superconductors and topological insulators are predicted to host unusual zero energy bound states known as Majorana fermions, which can robustly store and process quantum information. Here, I will discuss our studies of such heterostructures through phase-coherent transport, which can act as a unique probe of Majorana fermions. We have extensively explored topological insulator Josephson junctions through SQUID and single-junction diffraction patterns, whose unusual behavior give evidence for low-energy Andreev bound states. In topological insulator devices with closely spaced normal and superconducting leads, we observe prominent Fabry-Perot oscillations, signifying gate-tunable, quasi-ballistic transport that can elegantly interact with Andreev reflection. Superconducting disks deposited on the surface of a topological insulator generate Aharonov-Bohm-like oscillations, giving evidence for unusual states lying near the interface between the superconductor and topological insulator surface. Our results point the way towards sophisticated interferometers that can detect and read out the state of Majorana fermions in topological systems. This work was done in collaboration with Cihan Kurter, Yew San Hor, and Dale Van Harlingen. We acknowledge funding from Microsoft Project Q.
Promoting Gender Parity in Basic Education: Lessons from a Technical Cooperation Project in Yemen
ERIC Educational Resources Information Center
Yuki, Takako; Mizuno, Keiko; Ogawa, Keiichi; Mihoko, Sakai
2013-01-01
Many girls are not sent to school in Yemen, despite basic education being free as well as compulsory for all children aged 6-15. Aiming to improve girls' enrollment by increasing parental and community involvement, the Japan International Cooperation Agency (JICA) offered a technical cooperation project in June 2005 called Broadening Regional…
NASA Astrophysics Data System (ADS)
Xiang, Qian-Fei; Bi, Xiao-Jun; Yin, Peng-Fei; Yu, Zhao-Huan
2018-03-01
We study the impact of fermionic dark matter (DM) on projected Higgs precision measurements at the Circular Electron Positron Collider (CEPC), including the one-loop effects on the e+e-→Z h cross section and the Higgs boson diphoton decay, as well as the tree-level effects on the Higgs boson invisible decay. As illuminating examples, we discuss two UV-complete DM models, whose dark sector contains electroweak multiplets that interact with the Higgs boson via Yukawa couplings. The CEPC sensitivity to these models and current constraints from DM detection and collider experiments are investigated. We find that there exist some parameter regions where the Higgs measurements at the CEPC will be complementary to current DM searches.
Bold Diagrammatic Monte Carlo for Fermionic and Fermionized Systems
NASA Astrophysics Data System (ADS)
Svistunov, Boris
2013-03-01
In three different fermionic cases--repulsive Hubbard model, resonant fermions, and fermionized spins-1/2 (on triangular lattice)--we observe the phenomenon of sign blessing: Feynman diagrammatic series features finite convergence radius despite factorial growth of the number of diagrams with diagram order. Bold diagrammatic Monte Carlo technique allows us to sample millions of skeleton Feynman diagrams. With the universal fermionization trick we can fermionize essentially any (bosonic, spin, mixed, etc.) lattice system. The combination of fermionization and Bold diagrammatic Monte Carlo yields a universal first-principle approach to strongly correlated lattice systems, provided the sign blessing is a generic fermionic phenomenon. Supported by NSF and DARPA
Fermion masses through four-fermion condensates
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ayyar, Venkitesh; Chandrasekharan, Shailesh
Fermion masses can be generated through four-fermion condensates when symmetries prevent fermion bilinear condensates from forming. This less explored mechanism of fermion mass generation is responsible for making four reduced staggered lattice fermions massive at strong couplings in a lattice model with a local four-fermion coupling. The model has a massless fermion phase at weak couplings and a massive fermion phase at strong couplings. In particular there is no spontaneous symmetry breaking of any lattice symmetries in both these phases. Recently it was discovered that in three space-time dimensions there is a direct second order phase transition between the twomore » phases. Here we study the same model in four space-time dimensions and find results consistent with the existence of a narrow intermediate phase with fermion bilinear condensates, that separates the two asymptotic phases by continuous phase transitions.« less
What is the optimal way to prepare a Bell state using measurement and feedback?
NASA Astrophysics Data System (ADS)
Martin, Leigh; Sayrafi, Mahrud; Whaley, K. Birgitta
2017-12-01
Recent work has shown that the use of quantum feedback can significantly enhance both the speed and success rate of measurement-based remote entanglement generation, but it is generally unknown what feedback protocols are optimal for these tasks. Here we consider two common measurements that are capable of projecting into pairwise entangled states, namely half- and full-parity measurements of two qubits, and determine in each case a globally optimal protocol for generation of entanglement. For the half-parity measurement, we rederive a previously described protocol using more general methods and prove that it is globally optimal for several figures of merit, including maximal concurrence or fidelity and minimal time to reach a specified concurrence or fidelity. For the full-parity measurement, we derive a protocol for rapid entanglement generation related to that of (Hill, Ralph, Phys. Rev. A 77, 014305), and then map the dynamics of the concurrence of the state to the Bloch vector length of an effective qubit. This mapping allows us to prove several optimality results for feedback protocols with full-parity measurements. We further show that our full-parity protocol transfers entanglement optimally from one qubit to the other amongst all measurement-based schemes. The methods developed here will be useful for deriving feedback protocols and determining their optimality properties in many other quantum systems subject to measurement and unitary operations.
Light weakly coupled axial forces: models, constraints, and projections
Kahn, Yonatan; Krnjaic, Gordan; Mishra-Sharma, Siddharth; ...
2017-05-01
Here, we investigate the landscape of constraints on MeV-GeV scale, hidden U(1) forces with nonzero axial-vector couplings to Standard Model fermions. While the purely vector-coupled dark photon, which may arise from kinetic mixing, is a well-motivated scenario, several MeV-scale anomalies motivate a theory with axial couplings which can be UV-completed consistent with Standard Model gauge invariance. Moreover, existing constraints on dark photons depend on products of various combinations of axial and vector couplings, making it difficult to isolate the e ects of axial couplings for particular flavors of SM fermions. We present a representative renormalizable, UV-complete model of a darkmore » photon with adjustable axial and vector couplings, discuss its general features, and show how some UV constraints may be relaxed in a model with nonrenormalizable Yukawa couplings at the expense of fine-tuning. We survey the existing parameter space and the projected reach of planned experiments, brie y commenting on the relevance of the allowed parameter space to low-energy anomalies in π 0 and 8Be* decay.« less
Light weakly coupled axial forces: models, constraints, and projections
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kahn, Yonatan; Krnjaic, Gordan; Mishra-Sharma, Siddharth
Here, we investigate the landscape of constraints on MeV-GeV scale, hidden U(1) forces with nonzero axial-vector couplings to Standard Model fermions. While the purely vector-coupled dark photon, which may arise from kinetic mixing, is a well-motivated scenario, several MeV-scale anomalies motivate a theory with axial couplings which can be UV-completed consistent with Standard Model gauge invariance. Moreover, existing constraints on dark photons depend on products of various combinations of axial and vector couplings, making it difficult to isolate the e ects of axial couplings for particular flavors of SM fermions. We present a representative renormalizable, UV-complete model of a darkmore » photon with adjustable axial and vector couplings, discuss its general features, and show how some UV constraints may be relaxed in a model with nonrenormalizable Yukawa couplings at the expense of fine-tuning. We survey the existing parameter space and the projected reach of planned experiments, brie y commenting on the relevance of the allowed parameter space to low-energy anomalies in π 0 and 8Be* decay.« less
Observation of three-component fermions in the topological semimetal molybdenum phosphide.
Lv, B Q; Feng, Z-L; Xu, Q-N; Gao, X; Ma, J-Z; Kong, L-Y; Richard, P; Huang, Y-B; Strocov, V N; Fang, C; Weng, H-M; Shi, Y-G; Qian, T; Ding, H
2017-06-29
In quantum field theory, Lorentz invariance leads to three types of fermion-Dirac, Weyl and Majorana. Although the existence of Weyl and Majorana fermions as elementary particles in high-energy physics is debated, all three types of fermion have been proposed to exist as low-energy, long-wavelength quasiparticle excitations in condensed-matter systems. The existence of Dirac and Weyl fermions in condensed-matter systems has been confirmed experimentally, and that of Majorana fermions is supported by various experiments. However, in condensed-matter systems, fermions in crystals are constrained by the symmetries of the 230 crystal space groups rather than by Lorentz invariance, giving rise to the possibility of finding other types of fermionic excitation that have no counterparts in high-energy physics. Here we use angle-resolved photoemission spectroscopy to demonstrate the existence of a triply degenerate point in the electronic structure of crystalline molybdenum phosphide. Quasiparticle excitations near a triply degenerate point are three-component fermions, beyond the conventional Dirac-Weyl-Majorana classification, which attributes Dirac and Weyl fermions to four- and two-fold degenerate points, respectively. We also observe pairs of Weyl points in the bulk electronic structure of the crystal that coexist with the three-component fermions. This material thus represents a platform for studying the interplay between different types of fermions. Our experimental discovery opens up a way of exploring the new physics of unconventional fermions in condensed-matter systems.
Constraints on models for the Higgs boson with exotic spin and parity in VH → Vbb final states.
Abazov, V M; Abbott, B; Acharya, B S; Adams, M; Adams, T; Agnew, J P; Alexeev, G D; Alkhazov, G; Alton, A; Askew, A; Atkins, S; Augsten, K; Avila, C; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barberis, E; Baringer, P; Bartlett, J F; Bassler, U; Bazterra, V; Bean, A; Begalli, M; Bellantoni, L; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bhat, P C; Bhatia, S; Bhatnagar, V; Blazey, G; Blessing, S; Bloom, K; Boehnlein, A; Boline, D; Boos, E E; Borissov, G; Borysova, M; Brandt, A; Brandt, O; Brock, R; Bross, A; Brown, D; Bu, X B; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Buszello, C P; Camacho-Pérez, E; Casey, B C K; Castilla-Valdez, H; Caughron, S; Chakrabarti, S; Chan, K M; Chandra, A; Chapon, E; Chen, G; Cho, S W; Choi, S; Choudhary, B; Cihangir, S; Claes, D; Clutter, J; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Cutts, D; Das, A; Davies, G; de Jong, S J; De La Cruz-Burelo, E; Déliot, F; Demina, R; Denisov, D; Denisov, S P; Desai, S; Deterre, C; DeVaughan, K; Diehl, H T; Diesburg, M; Ding, P F; Dominguez, A; Dubey, A; Dudko, L V; Duperrin, A; Dutt, S; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Evans, H; Evdokimov, V N; Fauré, A; Feng, L; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fuess, S; Garbincius, P H; Garcia-Bellido, A; García-González, J A; Gavrilov, V; Geng, W; Gerber, C E; Gershtein, Y; Ginther, G; Gogota, O; Golovanov, G; Grannis, P D; Greder, S; Greenlee, H; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guillemin, T; Gutierrez, G; Gutierrez, P; Haley, J; Han, L; Harder, K; Harel, A; Hauptman, J M; Hays, J; Head, T; Hebbeker, T; Hedin, D; Hegab, H; Heinson, A P; Heintz, U; Hensel, C; Heredia-De La Cruz, I; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hoeneisen, B; Hogan, J; Hohlfeld, M; Holzbauer, J L; Howley, I; Hubacek, Z; Hynek, V; Iashvili, I; Ilchenko, Y; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jayasinghe, A; Jeong, M S; Jesik, R; Jiang, P; Johns, K; Johnson, E; Johnson, M; Jonckheere, A; Jonsson, P; Joshi, J; Jung, A W; Juste, A; Kajfasz, E; Karmanov, D; Katsanos, I; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Kiselevich, I; Kohli, J M; Kozelov, A V; Kraus, J; Kumar, A; Kupco, A; Kurča, T; Kuzmin, V A; Lammers, S; Lebrun, P; Lee, H S; Lee, S W; Lee, W M; Lei, X; Lellouch, J; Li, D; Li, H; Li, L; Li, Q Z; Lim, J K; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, H; Liu, Y; Lobodenko, A; Lokajicek, M; Lopes de Sa, R; Luna-Garcia, R; Lyon, A L; Maciel, A K A; Madar, R; Magaña-Villalba, R; Malik, S; Malyshev, V L; Mansour, J; Martínez-Ortega, J; McCarthy, R; McGivern, C L; Meijer, M M; Melnitchouk, A; Menezes, D; Mercadante, P G; Merkin, M; Meyer, A; Meyer, J; Miconi, F; Mondal, N K; Mulhearn, M; Nagy, E; Narain, M; Nayyar, R; Neal, H A; Negret, J P; Neustroev, P; Nguyen, H T; Nunnemann, T; Orduna, J; Osman, N; Osta, J; Pal, A; Parashar, N; Parihar, V; Park, S K; Partridge, R; Parua, N; Patwa, A; Penning, B; Perfilov, M; Peters, Y; Petridis, K; Petrillo, G; Pétroff, P; Pleier, M-A; Podstavkov, V M; Popov, A V; Prewitt, M; Price, D; Prokopenko, N; Qian, J; Quadt, A; Quinn, B; Ratoff, P N; Razumov, I; Ripp-Baudot, I; Rizatdinova, F; Rominsky, M; Ross, A; Royon, C; Rubinov, P; Ruchti, R; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santos, A S; Savage, G; Savitskyi, M; Sawyer, L; Scanlon, T; Schamberger, R D; Scheglov, Y; Schellman, H; Schwanenberger, C; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shary, V; Shaw, S; Shchukin, A A; Simak, V; Skubic, P; Slattery, P; Smirnov, D; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Soustruznik, K; Stark, J; Stoyanova, D A; Strauss, M; Suter, L; Svoisky, P; Titov, M; Tokmenin, V V; Tsai, Y-T; Tsybychev, D; Tuchming, B; Tully, C; Uvarov, L; Uvarov, S; Uzunyan, S; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Verkheev, A Y; Vertogradov, L S; Verzocchi, M; Vesterinen, M; Vilanova, D; Vokac, P; Wahl, H D; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weichert, J; Welty-Rieger, L; Williams, M R J; Wilson, G W; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yamada, R; Yang, S; Yasuda, T; Yatsunenko, Y A; Ye, W; Ye, Z; Yin, H; Yip, K; Youn, S W; Yu, J M; Zennamo, J; Zhao, T G; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L
2014-10-17
We present constraints on models containing non-standard-model values for the spin J and parity P of the Higgs boson H in up to 9.7 fb(-1) of pp collisions at sqrt[s] = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. These are the first studies of Higgs boson J(P) with fermions in the final state. In the ZH → ℓℓbb, WH → ℓνbb, and ZH → ννbb final states, we compare the standard model (SM) Higgs boson prediction, J(P) = 0(+), with two alternative hypotheses, J(P) = 0(-) and J(P) = 2(+). We use a likelihood ratio to quantify the degree to which our data are incompatible with non-SM J(P) predictions for a range of possible production rates. Assuming that the production rate in the signal models considered is equal to the SM prediction, we reject the J(P) = 0(-) and J(P) = 2(+) hypotheses at the 97.6% CL and at the 99.0% CL, respectively. The expected exclusion sensitivity for a J(P) = 0(-) (J(P) = 2(+)) state is at the 99.86% (99.94%) CL. Under the hypothesis that our data are the result of a combination of the SM-like Higgs boson and either a J(P) = 0(-) or a J(P) = 2(+) signal, we exclude a J(P) = 0(-) fraction above 0.80 and a J(P) = 2(+) fraction above 0.67 at the 95% CL. The expected exclusion covers J(P) = 0(-) (J(P) = 2(+)) fractions above 0.54 (0.47).
Spin-orbit-coupled Fermi gases of two-electron ytterbium atoms
NASA Astrophysics Data System (ADS)
He, Chengdong; Song, Bo; Haciyev, Elnur; Ren, Zejian; Seo, Bojeong; Zhang, Shanchao; Liu, Xiong-Jun; Jo, Gyu-Boong
2017-04-01
Spin-orbit coupling (SOC) has been realized in bosonic and fermionic atomic gases opening an avenue to novel physics associated with spin-momentum locking. In this talk, we will demonstrate all-optical method coupling two hyperfine ground states of 173Yb fermions through a narrow optical transition 1S0 -> 3P1. An optical AC Stark shift is applied to split the ground hyperfine levels and separate out an effective spin-1/2 subspace from other spin states for the realization of SOC. The spin dephasing dynamics and the asymmetric momentum distribution of the spin-orbit coupled Fermi gas are observed as a hallmark of SOC. The implementation of all-optical SOC for ytterbium fermions should offer a new route to a long-lived spin-orbit coupled Fermi gas and greatly expand our capability in studying novel spin-orbit physics with alkaline-earth-like atoms. Other ongoing experimental works related to SOC will be also discussed. Funded by Croucher Foundation and Research Grants Council (RGC) of Hong Kong (Project ECS26300014, GRF16300215, GRF16311516, and Croucher Innovation Grants); MOST (Grant No. 2016YFA0301604) and NSFC (No. 11574008).
Fermion number of twisted kinks in the NJL2 model revisited
NASA Astrophysics Data System (ADS)
Thies, Michael
2018-03-01
As a consequence of axial current conservation, fermions cannot be bound in localized lumps in the massless Nambu-Jona-Lasinio model. In the case of twisted kinks, this manifests itself in a cancellation between the valence fermion density and the fermion density induced in the Dirac sea. To attribute the correct fermion number to these bound states requires an infrared regularization. Recently, this has been achieved by introducing a bare fermion mass, at least in the nonrelativistic regime of small twist angles and fermion numbers. Here, we propose a simpler regularization using a finite box which preserves integrability and can be applied at any twist angle. A consistent and physically plausible assignment of fermion number to all twisted kinks emerges.
Transport and magnetic properties in topological materials
NASA Astrophysics Data System (ADS)
Liang, Tian
The notion of topology has been the central topic of the condensed matter physics in recent years, ranging from 2D quantum hall (QH) and quantum spin hall (QSH) states, 3D topological insulators (TIs), topological crystalline insulators (TCIs), 3D Dirac/Weyl semimetals, and topological superconductors (TSCs) etc. The key notion of the topological materials is the bulk edge correspondence, i.e., in order to preserve the symmetry of the whole system (bulk+edge), edge states must exist to counter-compensate the broken symmetry of the bulk. Combined with the fact that the bulk is topologically protected, the edge states are robust due to the bulk edge correspondence. This leads to interesting phenomena of chiral edge states in 2D QH, helical edge states in 2D QSH, "parity anomaly'' (time reversal anomaly) in 3D TI, helical edge states in the mirror plane of TCI, chiral anomaly in Dirac/Weyl semimetals, Majorana fermions in the TSCs. Transport and magnetic properties of topological materials are investigated to yield intriguing phenomena. For 3D TI Bi1.1Sb0.9Te 2S, anomalous Hall effect (AHE) is observed, and for TCI Pb1-x SnxSe, Seebeck/Nernst measurements reveal the anomalous sign change of Nernst signals as well as the massive Dirac fermions. Ferroelectricity and pressure measurements show that TCI Pb1-xSnxTe undergoes quantum phase transition (QPT) from trivial insulator through Weyl semimetal to anomalous insulator. Dirac semimetals Cd3As2, Na 3Bi show interesting results such as the ultrahigh mobility 10 7cm2V-1s-1 protected from backscattering at zero magnetic field, as well as anomalous Nernst effect (ANE) for Cd3As2, and the negative longitudinal magnetoresistance (MR) due to chiral anomaly for Na3Bi. In-plane and out-of-plane AHE are observed for semimetal ZrTe5 by in-situ double-axes rotation measurements. For interacting system Eu2Ir2O7, full angle torque magnetometry measurements reveal the existence of orthogonal magnetization breaking the symmetry of handedness, as well as additional order parameter which breaks the underlying lattice symmetry. Heat capacity measurements for CoNb2O6 detect the neutral gapless fermion-like excitations near the quantum critical point (QCP) under transverse magnetic field. The implications of these phenomena are discussed.
Observation of three-component fermions in the topological semimetal molybdenum phosphide
NASA Astrophysics Data System (ADS)
Lv, B. Q.; Feng, Z.-L.; Xu, Q.-N.; Gao, X.; Ma, J.-Z.; Kong, L.-Y.; Richard, P.; Huang, Y.-B.; Strocov, V. N.; Fang, C.; Weng, H.-M.; Shi, Y.-G.; Qian, T.; Ding, H.
2017-06-01
In quantum field theory, Lorentz invariance leads to three types of fermion—Dirac, Weyl and Majorana. Although the existence of Weyl and Majorana fermions as elementary particles in high-energy physics is debated, all three types of fermion have been proposed to exist as low-energy, long-wavelength quasiparticle excitations in condensed-matter systems. The existence of Dirac and Weyl fermions in condensed-matter systems has been confirmed experimentally, and that of Majorana fermions is supported by various experiments. However, in condensed-matter systems, fermions in crystals are constrained by the symmetries of the 230 crystal space groups rather than by Lorentz invariance, giving rise to the possibility of finding other types of fermionic excitation that have no counterparts in high-energy physics. Here we use angle-resolved photoemission spectroscopy to demonstrate the existence of a triply degenerate point in the electronic structure of crystalline molybdenum phosphide. Quasiparticle excitations near a triply degenerate point are three-component fermions, beyond the conventional Dirac-Weyl-Majorana classification, which attributes Dirac and Weyl fermions to four- and two-fold degenerate points, respectively. We also observe pairs of Weyl points in the bulk electronic structure of the crystal that coexist with the three-component fermions. This material thus represents a platform for studying the interplay between different types of fermions. Our experimental discovery opens up a way of exploring the new physics of unconventional fermions in condensed-matter systems.
Non-Abelian statistics of vortices with non-Abelian Dirac fermions.
Yasui, Shigehiro; Hirono, Yuji; Itakura, Kazunori; Nitta, Muneto
2013-05-01
We extend our previous analysis on the exchange statistics of vortices having a single Dirac fermion trapped in each core to the case where vortices trap two Dirac fermions with U(2) symmetry. Such a system of vortices with non-Abelian Dirac fermions appears in color superconductors at extremely high densities and in supersymmetric QCD. We show that the exchange of two vortices having doublet Dirac fermions in each core is expressed by non-Abelian representations of a braid group, which is explicitly verified in the matrix representation of the exchange operators when the number of vortices is up to four. We find that the result contains the matrices previously obtained for the vortices with a single Dirac fermion in each core as a special case. The whole braid group does not immediately imply non-Abelian statistics of identical particles because it also contains exchanges between vortices with different numbers of Dirac fermions. However, we find that it does contain, as its subgroup, genuine non-Abelian statistics for the exchange of the identical particles, that is, vortices with the same number of Dirac fermions. This result is surprising compared with conventional understanding because all Dirac fermions are defined locally at each vortex, unlike the case of Majorana fermions for which Dirac fermions are defined nonlocally by Majorana fermions located at two spatially separated vortices.
Lattice calculation of electric dipole moments and form factors of the nucleon
DOE Office of Scientific and Technical Information (OSTI.GOV)
Abramczyk, M.; Aoki, S.; Blum, T.
In this paper, we analyze commonly used expressions for computing the nucleon electric dipole form factors (EDFF)more » $$F_3$$ and moments (EDM) on a lattice and find that they lead to spurious contributions from the Pauli form factor $$F_2$$ due to inadequate definition of these form factors when parity mixing of lattice nucleon fields is involved. Using chirally symmetric domain wall fermions, we calculate the proton and the neutron EDFF induced by the CP-violating quark chromo-EDM interaction using the corrected expression. In addition, we calculate the electric dipole moment of the neutron using a background electric field that respects time translation invariance and boundary conditions, and we find that it decidedly agrees with the new formula but not the old formula for $$F_3$$. In conclusion, we analyze some selected lattice results for the nucleon EDM and observe that after the correction is applied, they either agree with zero or are substantially reduced in magnitude, thus reconciling their difference from phenomenological estimates of the nucleon EDM.« less
Lattice calculation of electric dipole moments and form factors of the nucleon
Abramczyk, M.; Aoki, S.; Blum, T.; ...
2017-07-10
In this paper, we analyze commonly used expressions for computing the nucleon electric dipole form factors (EDFF)more » $$F_3$$ and moments (EDM) on a lattice and find that they lead to spurious contributions from the Pauli form factor $$F_2$$ due to inadequate definition of these form factors when parity mixing of lattice nucleon fields is involved. Using chirally symmetric domain wall fermions, we calculate the proton and the neutron EDFF induced by the CP-violating quark chromo-EDM interaction using the corrected expression. In addition, we calculate the electric dipole moment of the neutron using a background electric field that respects time translation invariance and boundary conditions, and we find that it decidedly agrees with the new formula but not the old formula for $$F_3$$. In conclusion, we analyze some selected lattice results for the nucleon EDM and observe that after the correction is applied, they either agree with zero or are substantially reduced in magnitude, thus reconciling their difference from phenomenological estimates of the nucleon EDM.« less
Quark and lepton mixing as manifestations of violated mirror symmetry
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dyatlov, I. T., E-mail: dyatlov@thd.pnpi.spb.ru
2015-06-15
The existence of heavy mirror analogs of ordinary fermions would provide deeper insight into the gedanken paradox appearing in the Standard Model upon direct parity violation and consisting in a physical distinguishability of left- and right-hand coordinate frames. Arguments are presented in support of the statement that such mirror states may also be involved in the formation of observed properties of the system of Standard Model quarks and leptons—that is, their mass spectra and their weak-mixing matrices: (i) In the case of the involvement of mirror generations, the quark mixing matrix assumes the experimentally observed form. It is determined bymore » the constraints imposed by weak SU(2) symmetry and by the quark-mass hierarchy. (ii) Under the same conditions and upon the involvement of mirror particles, the lepton mixing matrix (neutrino mixing) may become drastically different from its quark analog—the Cabibbo-Kobayashi-Maskawa matrix; that is, it may acquire properties suggested by experimental data. This character of mixing is also indicative of an inverse mass spectrum of Standard Model neutrinos and their Dirac (not Majorana) nature.« less
Levy, Niv; Zhang, Tong; Ha, Jeonghoon; Sharifi, Fred; Talin, A Alec; Kuk, Young; Stroscio, Joseph A
2013-03-15
Topological superconductors represent a newly predicted phase of matter that is topologically distinct from conventional superconducting condensates of Cooper pairs. As a manifestation of their topological character, topological superconductors support solid-state realizations of Majorana fermions at their boundaries. The recently discovered superconductor Cu(x)Bi(2)Se(3) has been theoretically proposed as an odd-parity superconductor in the time-reversal-invariant topological superconductor class, and point-contact spectroscopy measurements have reported the observation of zero-bias conductance peaks corresponding to Majorana states in this material. Here we report scanning tunneling microscopy measurements of the superconducting energy gap in Cu(x)Bi(2)Se(3) as a function of spatial position and applied magnetic field. The tunneling spectrum shows that the density of states at the Fermi level is fully gapped without any in-gap states. The spectrum is well described by the Bardeen-Cooper-Schrieffer theory with a momentum independent order parameter, which suggests that Cu(x)Bi(2)Se(3) is a classical s-wave superconductor contrary to previous expectations and measurements.
Dark revelations of the [SU(3)]3 and [SU(3)]4 gauge extensions of the standard model
NASA Astrophysics Data System (ADS)
Kownacki, Corey; Ma, Ernest; Pollard, Nicholas; Popov, Oleg; Zakeri, Mohammadreza
2018-02-01
Two theoretically well-motivated gauge extensions of the standard model are SU(3)C × SU(3)L × SU(3)R and SU(3)q × SU(3)L × SU(3)l × SU(3)R, where SU(3)q is the same as SU(3)C and SU(3)l is its color leptonic counterpart. Each has three variations, according to how SU(3)R is broken. It is shown here for the first time that a built-in dark U(1)D gauge symmetry exists in all six versions. However, the corresponding symmetry breaking pattern does not reduce properly to that of the standard model, unless an additional Z2‧ symmetry is defined, so that U(1)D ×Z2‧ is broken to Z2 dark parity. The available dark matter candidates in each case include fermions, scalars, as well as vector gauge bosons. This work points to the possible unity of matter with dark matter, the origin of which may not be ad hoc.
NASA Astrophysics Data System (ADS)
Yan, Jun; Chen, Shao-Yu; Naylor, Carl; Goldstein, Thomas; Johnson, Charlie; Venkataraman, Dhandapani; Ramasubramaniam, Ashwin
Distorted octahedral (T') transition metal dichalcogenides (TMDCs) are topologically interesting material systems. Inversion-symmetry-broken bulk T'-TMDCs are predicted to be type II Weyl semimetals and inversion-symmetric monolayer (1L) T'-TMDCs are shown to be 2D topological insulators. In this talk, I will show that both the inversion symmetry and the mirror symmetry are important for understanding the lattice dynamics and Raman scattering of T'-TMDCs. The mirror plane that is perpendicular to the zigzag transition metal atomic chain classifies lattice vibrations into z-modes and m-modes where ` z' stands for zigzag and ` m' stands for mirror. Raman active z- and m- modes can be experimentally determined with light-polarization and crystal angle-resolved Raman tensor analysis. We report observation of all 9 even-parity zone-center phonons in 1L-T'-MoTe2. In bulk T'-MoTe2, we monitor inversion symmetry breaking with the shear lattice vibrations, which is important for supporting Weyl fermions. This work is supported by the Armstrong Fund for Science and NSF EFRI 2DARE EFMA-1542879.
Fermion number anomaly with the fluffy mirror fermion
NASA Astrophysics Data System (ADS)
Okumura, Ken-ichi; Suzuki, Hiroshi
2016-12-01
Quite recently, Grabowska and Kaplan presented a 4-dimensional lattice formulation of chiral gauge theories based on the chiral overlap operator. We study this formulation from the perspective of the fermion number anomaly and possible associated phenomenology. A simple argument shows that the consistency of the formulation implies that the fermion with the opposite chirality to the physical one, the "fluffy mirror fermion" or "fluff", suffers from the fermion number anomaly in the same magnitude (with the opposite sign) as the physical fermion. This immediately shows that if at least one of the fluff quarks is massless, the formulation provides a simple viable solution to the strong CP problem. Also, if the fluff interacts with gravity essentially in the same way as the physical fermion, the formulation can realize the asymmetric dark matter scenario.
State sum constructions of spin-TFTs and string net constructions of fermionic phases of matter
Bhardwaj, Lakshya; Gaiotto, Davide; Kapustin, Anton
2017-04-18
It is possible to describe fermionic phases of matter and spin-topological field theories in 2+1d in terms of bosonic “shadow” theories, which are obtained from the original theory by “gauging fermionic parity”. Furthemore, the fermionic/spin theories are recovered from their shadow by a process of fermionic anyon condensation: gauging a one-form symmetry generated by quasi-particles with fermionic statistics. We apply the formalism to theories which admit gapped boundary conditions. We obtain Turaev-Viro-like and Levin-Wen-like constructions of fermionic phases of matter. Here, we describe the group structure of fermionic SPT phases protected by Z 2f × G. The quaternion group makesmore » a surprise appearance.« less
Chip-to-chip entanglement of transmon qubits using engineered measurement fields
NASA Astrophysics Data System (ADS)
Dickel, C.; Wesdorp, J. J.; Langford, N. K.; Peiter, S.; Sagastizabal, R.; Bruno, A.; Criger, B.; Motzoi, F.; DiCarlo, L.
2018-02-01
While the on-chip processing power in circuit QED devices is growing rapidly, an open challenge is to establish high-fidelity quantum links between qubits on different chips. Here, we show entanglement between transmon qubits on different cQED chips with 49 % concurrence and 73 % Bell-state fidelity. We engineer a half-parity measurement by successively reflecting a coherent microwave field off two nearly identical transmon-resonator systems. By ensuring the measured output field does not distinguish |01 > from |10 > , unentangled superposition states are probabilistically projected onto entangled states in the odd-parity subspace. We use in situ tunability and an additional weakly coupled driving field on the second resonator to overcome imperfect matching due to fabrication variations. To demonstrate the flexibility of this approach, we also produce an even-parity entangled state of similar quality, by engineering the matching of outputs for the |00 > and |11 > states. The protocol is characterized over a range of measurement strengths using quantum state tomography showing good agreement with a comprehensive theoretical model.
High-temperature atomic superfluidity in lattice Bose-Fermi mixtures.
Illuminati, Fabrizio; Albus, Alexander
2004-08-27
We consider atomic Bose-Fermi mixtures in optical lattices and study the superfluidity of fermionic atoms due to s-wave pairing induced by boson-fermion interactions. We prove that the induced fermion-fermion coupling is always attractive if the boson-boson on-site interaction is repulsive, and predict the existence of an enhanced BEC-BCS crossover as the strength of the lattice potential is varied. We show that for direct on-site fermion-fermion repulsion, the induced attraction can give rise to superfluidity via s-wave pairing at striking variance with the case of pure systems of fermionic atoms with direct repulsive interactions.
MSW-resonant fermion mixing during reheating
NASA Astrophysics Data System (ADS)
Kanai, Tsuneto; Tsujikawa, Shinji
2003-10-01
We study the dynamics of reheating in which an inflaton field couples two flavor fermions through Yukawa-couplings. When two fermions have a mixing term with a constant coupling, we show that the Mikheyev-Smirnov-Wolfenstein (MSW)-type resonance emerges due to a time-dependent background in addition to the standard fermion creation via parametric resonance. This MSW resonance not only alters the number densities of fermions generated by a preheating process but also can lead to the larger energy transfer from the inflaton to fermions. Our mechanism can provide additional source terms for the creation of superheavy fermions which may be relevant for the leptogenesis scenario.
Xu, Yong; Chu, Rui-Lin; Zhang, Chuanwei
2014-04-04
Weyl fermions, first proposed for describing massless chiral Dirac fermions in particle physics, have not been observed yet in experiments. Recently, much effort has been devoted to explore Weyl fermions around band touching points of single-particle energy dispersions in certain solid state materials (named Weyl semimetals), similar as graphene for Dirac fermions. Here we show that such Weyl semimetals also exist in the quasiparticle excitation spectrum of a three-dimensional spin-orbit-coupled Fulde-Ferrell superfluid. By varying Zeeman fields, the properties of Weyl fermions, such as their creation and annihilation, number and position, as well as anisotropic linear dispersions around band touching points, can be tuned. We study the manifestation of anisotropic Weyl fermions in sound speeds of Fulde-Ferrell fermionic superfluids, which are detectable in experiments.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bhardwaj, Lakshya; Gaiotto, Davide; Kapustin, Anton
It is possible to describe fermionic phases of matter and spin-topological field theories in 2+1d in terms of bosonic “shadow” theories, which are obtained from the original theory by “gauging fermionic parity”. Furthemore, the fermionic/spin theories are recovered from their shadow by a process of fermionic anyon condensation: gauging a one-form symmetry generated by quasi-particles with fermionic statistics. We apply the formalism to theories which admit gapped boundary conditions. We obtain Turaev-Viro-like and Levin-Wen-like constructions of fermionic phases of matter. Here, we describe the group structure of fermionic SPT phases protected by Z 2f × G. The quaternion group makesmore » a surprise appearance.« less
Superfluid Boson-Fermion Mixture: Structure Formation and Collective Periodic Motion
NASA Astrophysics Data System (ADS)
Mitra, A.
2018-01-01
Multiple periodic domain formation due to a modulation instability in a boson-fermion mixture superfluid in the unitary regime has been studied. The periodicity of the structure evolves with time. At the early stage of evolution, bosonic domains show the periodic nature, whereas the periodicity in the fermionic (Cooper pair) domains appears at the late stage of evolution. The nature of interatomic interspecies interactions affects the domain formation. In a harmonic trap, the mixture executes an undamped oscillation. The frequency of the oscillation depends on the relative coupling strength between boson-fermion and fermion-fermion. The repulsive boson-fermion interaction reduces the oscillation frequency, whereas the attractive interaction enhances the frequency significantly.
Fermion emission from a Julia-Zee dyon
DOE Office of Scientific and Technical Information (OSTI.GOV)
Blaer, A.S.; Christ, N.H.; Tang, J.
1982-04-15
A relationship is obtained between the S matrix for the charge-exchange scattering of a fermion by a Julia-Zee dyon and the flux of fermions emitted by the dyon when the mass of the fermions is sufficiently small. In the limit of a pointlike dyon, the required S-matrix elements are obtained in closed form and the corresponding fermion flux is computed explicitly.
Spin-orbital quantum liquid on the honeycomb lattice
NASA Astrophysics Data System (ADS)
Corboz, Philippe
2013-03-01
The symmetric Kugel-Khomskii can be seen as a minimal model describing the interactions between spin and orbital degrees of freedom in transition-metal oxides with orbital degeneracy, and it is equivalent to the SU(4) Heisenberg model of four-color fermionic atoms. We present simulation results for this model on various two-dimensional lattices obtained with infinite projected-entangled pair states (iPEPS), an efficient variational tensor-network ansatz for two dimensional wave functions in the thermodynamic limit. This approach can be seen as a two-dimensional generalization of matrix product states - the underlying ansatz of the density matrix renormalization group method. We find a rich variety of exotic phases: while on the square and checkerboard lattices the ground state exhibits dimer-Néel order and plaquette order, respectively, quantum fluctuations on the honeycomb lattice destroy any order, giving rise to a spin-orbital liquid. Our results are supported from flavor-wave theory and exact diagonalization. Furthermore, the properties of the spin-orbital liquid state on the honeycomb lattice are accurately accounted for by a projected variational wave-function based on the pi-flux state of fermions on the honeycomb lattice at 1/4-filling. In that state, correlations are algebraic because of the presence of a Dirac point at the Fermi level, suggesting that the ground state is an algebraic spin-orbital liquid. This model provides a good starting point to understand the recently discovered spin-orbital liquid behavior of Ba3CuSb2O9. The present results also suggest to choose optical lattices with honeycomb geometry in the search for quantum liquids in ultra-cold four-color fermionic atoms. We acknowledge the financial support from the Swiss National Science Foundation.
Strategies for Reforming Workforce Preparation Programs in Europe
ERIC Educational Resources Information Center
Stenstrom, Marja-Leena; Lasonen, Johanna
2004-01-01
The Post-16 Strategies project coordinated by Dr. Johanna Lasonen from 1996 to 1998 was chiefly concerned with four post-16 education strategies: (1) "vocational enhancement"; (2) "mutual enrichment"; (3) "linkages;" and (4) "unification." These four strategies to promote parity of esteem between vocational…
NASA Astrophysics Data System (ADS)
Yagi, Kent; Yang, Huan
2018-05-01
The recent discovery of gravitational-wave events has offered us unique test beds of gravity in the strong and dynamical field regime. One possible modification to General Relativity is the gravitational parity violation that arises naturally from quantum gravity. Such parity violation gives rise to the so-called amplitude birefringence in gravitational waves, in which one of the circularly polarized modes is amplified while the other one is suppressed during their propagation. In this paper, we study how well one can measure gravitational parity violation via the amplitude birefringence effect of gravitational waves sourced by stellar-mass black hole binaries. We choose Chern-Simons gravity as an example and work within an effective field theory formalism to ensure that the approximate theory is well posed. We consider gravitational waves from both individual sources and stochastic gravitational-wave backgrounds. Regarding bounds from individual sources, we estimate such bounds using a Fisher analysis and carry out Monte Carlo simulations by randomly distributing sources over their sky location and binary orientation. We find that the bounds on the scalar field evolution in Chern-Simons gravity from the recently discovered gravitational-wave events are too weak to satisfy the weak Chern-Simons approximation, while aLIGO with its design sensitivity can place meaningful bounds. Regarding bounds from stochastic gravitational-wave backgrounds, we set the threshold signal-to-noise ratio for detection of the parity-violation mode as 5 and estimate projected bounds with future detectors assuming that signals are consistent with no parity violation. In an ideal situation in which all the source parameters and binary black hole merger-rate history are known a priori, we find that a network of two third-generation detectors is able to place bounds that are comparable to or slightly stronger than binary pulsar bounds. In a more realistic situation in which one does not have such information beforehand, approximate bounds can be derived if the regular parity-insensitive mode is detected and the peak redshift of the merger-rate history is known theoretically. Since gravitational-wave observations probe either the difference in parity violation between the source and the detector (with individual sources) or the line-of-sight cosmological integration of the scalar field (with gravitational-wave backgrounds), such bounds are complementary to local measurements from solar system experiments and binary pulsar observations.
Charged fermions below 100 GeV
NASA Astrophysics Data System (ADS)
Egana-Ugrinovic, Daniel; Low, Matthew; Ruderman, Joshua T.
2018-05-01
How light can a fermion be if it has unit electric charge? We revisit the lore that LEP robustly excludes charged fermions lighter than about 100 GeV. We review LEP chargino searches, and find them to exclude charged fermions lighter than 90 GeV, assuming a higgsino-like cross section. However, if the charged fermion couples to a new scalar, destructive interference among production channels can lower the LEP cross section by a factor of 3. In this case, we find that charged fermions as light as 75 GeV can evade LEP bounds, while remaining consistent with constraints from the LHC. As the LHC collects more data, charged fermions in the 75-100 GeV mass range serve as a target for future monojet and disappearing track searches.
Quantum canonical ensemble: A projection operator approach
NASA Astrophysics Data System (ADS)
Magnus, Wim; Lemmens, Lucien; Brosens, Fons
2017-09-01
Knowing the exact number of particles N, and taking this knowledge into account, the quantum canonical ensemble imposes a constraint on the occupation number operators. The constraint particularly hampers the systematic calculation of the partition function and any relevant thermodynamic expectation value for arbitrary but fixed N. On the other hand, fixing only the average number of particles, one may remove the above constraint and simply factorize the traces in Fock space into traces over single-particle states. As is well known, that would be the strategy of the grand-canonical ensemble which, however, comes with an additional Lagrange multiplier to impose the average number of particles. The appearance of this multiplier can be avoided by invoking a projection operator that enables a constraint-free computation of the partition function and its derived quantities in the canonical ensemble, at the price of an angular or contour integration. Introduced in the recent past to handle various issues related to particle-number projected statistics, the projection operator approach proves beneficial to a wide variety of problems in condensed matter physics for which the canonical ensemble offers a natural and appropriate environment. In this light, we present a systematic treatment of the canonical ensemble that embeds the projection operator into the formalism of second quantization while explicitly fixing N, the very number of particles rather than the average. Being applicable to both bosonic and fermionic systems in arbitrary dimensions, transparent integral representations are provided for the partition function ZN and the Helmholtz free energy FN as well as for two- and four-point correlation functions. The chemical potential is not a Lagrange multiplier regulating the average particle number but can be extracted from FN+1 -FN, as illustrated for a two-dimensional fermion gas.
Ghost free systems with coexisting bosons and fermions
NASA Astrophysics Data System (ADS)
Kimura, Rampei; Sakakihara, Yuki; Yamaguchi, Masahide
2017-08-01
We study the coexistence system of both bosonic and fermionic degrees of freedom. Even if a Lagrangian does not include higher derivatives, fermionic ghosts exist. For a Lagrangian with up to first derivatives, we find the fermionic ghost free condition in Hamiltonian analysis, which is found to be the same as requiring that the equations of motion of fermions be first order in Lagrangian formulation. When fermionic degrees of freedom are present, the uniqueness of time evolution is not guaranteed a priori because of the Grassmann property. We confirm that the additional condition, which is introduced to close Hamiltonian analysis, also ensures the uniqueness of the time evolution of the system.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gyenis, András; Inoue, Hiroyuki; Jeon, Sangjun
Following the intense studies on topological insulators, significant efforts have recently been devoted to the search for gapless topological systems. These materials not only broaden the topological classification of matter but also provide a condensed matter realization of various relativistic particles and phenomena previously discussed mainly in high energy physics. Weyl semimetals host massless, chiral, low-energy excitations in the bulk electronic band structure, whereas a symmetry protected pair of Weyl fermions gives rise to massless Dirac fermions.Weemployed scanning tunneling microscopy/spectroscopy to explore the behavior of electronic states both on the surface and in the bulk of topological semimetal phases. Bymore » mapping the quasiparticle interference (QPI) and emerging Landau levels at high magnetic field in Dirac semimetals Cd 3As 2 and Na 3Bi, we observed extended Dirac-like bulk electronic bands. QPI imaged on Weyl semimetal TaAs demonstrated the predicted momentum dependent delocalization of Fermi arc surface states in the vicinity of the surface projected Weyl nodes.« less
NASA Astrophysics Data System (ADS)
Gritsan, Andrei V.; Röntsch, Raoul; Schulze, Markus; Xiao, Meng
2016-09-01
In this paper, we investigate anomalous interactions of the Higgs boson with heavy fermions, employing shapes of kinematic distributions. We study the processes p p →t t ¯+H , b b ¯+H , t q +H , and p p →H →τ+τ- and present applications of event generation, reweighting techniques for fast simulation of anomalous couplings, as well as matrix element techniques for optimal sensitivity. We extend the matrix element likelihood approach (MELA) technique, which proved to be a powerful matrix element tool for Higgs boson discovery and characterization during Run I of the LHC, and implement all analysis tools in the JHU generator framework. A next-to-leading-order QCD description of the p p →t t ¯+H process allows us to investigate the performance of the MELA in the presence of extra radiation. Finally, projections for LHC measurements through the end of Run III are presented.
Particle-hole symmetry and composite fermions in fractional quantum Hall states
NASA Astrophysics Data System (ADS)
Nguyen, Dung Xuan; Golkar, Siavash; Roberts, Matthew M.; Son, Dam Thanh
2018-05-01
We study fractional quantum Hall states at filling fractions in the Jain sequences using the framework of composite Dirac fermions. Synthesizing previous work, we write an effective field theory consistent with all symmetry requirements, including Galilean invariance and particle-hole symmetry. Employing a Fermi-liquid description, we demonstrate the appearance of the Girvin-Macdonald-Platzman algebra and compute the dispersion relation of neutral excitations and various response functions. Our results satisfy requirements of particle-hole symmetry. We show that while the dispersion relation obtained from the modified random-phase approximation (MRPA) of the Halperin-Lee-Read (HLR) theory is particle-hole symmetric, correlation functions obtained from this scheme are not. The results of the Dirac theory are shown to be consistent with the Haldane bound on the projected structure factor, while those of the MPRA of the HLR theory violate it.
DOE Office of Scientific and Technical Information (OSTI.GOV)
NONE
1998-10-16
A workshop was held at the RIKEN-BNL Research Center on October 16, 1998, as part of the first anniversary celebration for the center. This meeting brought together the physicists from RIKEN-BNL, BNL and Columbia who are using the QCDSP (Quantum Chromodynamics on Digital Signal Processors) computer at the RIKEN-BNL Research Center for studies of QCD. Many of the talks in the workshop were devoted to domain wall fermions, a discretization of the continuum description of fermions which preserves the global symmetries of the continuum, even at finite lattice spacing. This formulation has been the subject of analytic investigation for somemore » time and has reached the stage where large-scale simulations in QCD seem very promising. With the computational power available from the QCDSP computers, scientists are looking forward to an exciting time for numerical simulations of QCD.« less
Exactly Solvable Models for Topological Phases of Matter
NASA Astrophysics Data System (ADS)
Tarantino, Nicolas Alessandro
Topological systems are characterized by some collection of features which remain unchanged under deformations of the Hamiltonian which leave the band gap open. The earliest examples of these were free fermion systems, allowing us to study the band structure to determine if a candidate material supports topological features. However, we can also ask the reversed question, i.e. Given a band gap, what topological features can be engineered? This classification problem proved to have numerous answers depending on which extra assumptions we allow, producing many candidate phases. While free fermion topological features could be classified by their band structures (culminating in the 10-fold way), strongly interacting systems defied this approach, and so classification outstripped the construction of even the most elementary Hamiltonians, leaving us with a number of phases which could exist, but do not have a single strongly interacting representative. The purpose of this thesis is to resolve this in certain cases by constructing commuting projector models (CPM), a class of exactly solvable models, for two types of topological phases, known as symmetry enriched topological (SET) order and fermionic symmetry protected topological (SPT) phases respectively. After introducing the background and history of commuting projector models, we will move on to the details of how these Hamiltonians are built. In the first case, we construct a CPM for a SET, showing how to encode the necessary group cohomology data into a lattice model. In the second, we construct a CPM for a fermionic SPT, and find that we must include a combinatorial representation of a spin structure to make the model consistent. While these two projects were independent, they are linked thematically by a technique known as decoration, where extra data is encoded onto simple models to generate exotic phases.
Scales of mass generation for quarks, leptons, and majorana neutrinos.
Dicus, Duane A; He, Hong-Jian
2005-06-10
We study 2-->n inelastic fermion-(anti)fermion scattering into multiple longitudinal weak gauge bosons and derive universal upper bounds on the scales of fermion mass generation by imposing unitarity of the S matrix. We place new upper limits on the scales of fermion mass generation, independent of the electroweak symmetry breaking scale. Strikingly, we find that the strongest 2-->n limits fall in a narrow range, 3-170 TeV (with n=2-24), depending on the observed fermion masses.
Achieving Mental Health Care Parity Might Require Changes In Payments And Competition.
McGuire, Thomas G
2016-06-01
One of the most prominent features of the Affordable Care Act has been the promotion of individual health plans chosen by consumers in the Marketplaces. These plans are subject to regulation and paid by risk-adjusted capitation, a set of policies known as managed competition. Individual health insurance markets, however, are vulnerable to what economists describe as efficiency problems stemming from adverse selection, and Marketplaces are no exception. Health plans have incentives to discriminate against services used by people with certain chronic illnesses, including mental health conditions. Parity regulations, which dictate coverage for mental health benefits on par with medical and surgical benefits, can eliminate discrimination in coverage but redirect discrimination toward hard-to-regulate tactics from managed care such as restrictive network design and provider payment. This article reviews policy options to contend with ongoing selection issues. "Better enforcement" of parity has less chance of success than more fundamental but feasible changes in the way plans are paid or in the way competition among plans is structured. Project HOPE—The People-to-People Health Foundation, Inc.
Stochastic quantization and holographic Wilsonian renormalization group of free massive fermion
NASA Astrophysics Data System (ADS)
Moon, Sung Pil
2018-06-01
We examine a suggested relation between stochastic quantization and the holographic Wilsonian renormalization group in the massive fermion case on Euclidean AdS space. The original suggestion about the general relation between the two theories is posted in arXiv:1209.2242. In the previous researches, it is already verified that scalar fields, U(1) gauge fields, and massless fermions are consistent with the relation. In this paper, we examine the relation in the massive fermion case. Contrary to the other case, in the massive fermion case, the action needs particular boundary terms to satisfy boundary conditions. We finally confirm that the proposed suggestion is also valid in the massive fermion case.
ERIC Educational Resources Information Center
Stenstrom, Marja-Leena, Ed.
This four-part publication contains 19 papers on educational practices and promises for post-16 education in European countries. Part I, the introduction, contains these three papers: "Sharpening Post-16 Education Strategies: Building on the Results of the Previous Projects" (Johanna Lasonen); "'Parity of Esteem' and 'Integrated…
DOE Office of Scientific and Technical Information (OSTI.GOV)
Adams, David H.
2008-05-15
To investigate the viability of the 4th root trick for the staggered fermion determinant in a simpler setting, we consider a 2-taste (flavor) lattice fermion formulation with no taste mixing but with exact taste-nonsinglet chiral symmetries analogous to the taste-nonsinglet U(1){sub A} symmetry of staggered fermions. Creutz's objections to the rooting trick apply just as much in this setting. To counter them we show that the formulation has robust would-be zero modes in topologically nontrivial gauge backgrounds, and that these manifest themselves in a viable way in the rooted fermion determinant and also in the disconnected piece of the pseudoscalarmore » meson propagator as required to solve the U(1) problem. Also, our rooted theory is heuristically seen to be in the right universality class for QCD if the same is true for an unrooted mixed fermion action theory.« less
Parametrically coupled fermionic oscillators: Correlation functions and phase-space description
NASA Astrophysics Data System (ADS)
Ghosh, Arnab
2015-01-01
A fermionic analog of a parametric amplifier is used to describe the joint quantum state of the two interacting fermionic modes. Based on a two-mode generalization of the time-dependent density operator, time evolution of the fermionic density operator is determined in terms of its two-mode Wigner and P function. It is shown that the equation of motion of the Wigner function corresponds to a fermionic analog of Liouville's equation. The equilibrium density operator for fermionic fields developed by Cahill and Glauber is thus extended to a dynamical context to show that the mathematical structures of both the correlation functions and the weight factors closely resemble their bosonic counterpart. It has been shown that the fermionic correlation functions are marked by a characteristic upper bound due to Fermi statistics, which can be verified in the matter wave counterpart of photon down-conversion experiments.
Lorentz-violating type-II Dirac fermions in transition metal dichalcogenide PtTe2.
Yan, Mingzhe; Huang, Huaqing; Zhang, Kenan; Wang, Eryin; Yao, Wei; Deng, Ke; Wan, Guoliang; Zhang, Hongyun; Arita, Masashi; Yang, Haitao; Sun, Zhe; Yao, Hong; Wu, Yang; Fan, Shoushan; Duan, Wenhui; Zhou, Shuyun
2017-08-15
Topological semimetals have recently attracted extensive research interests as host materials to condensed matter physics counterparts of Dirac and Weyl fermions originally proposed in high energy physics. Although Lorentz invariance is required in high energy physics, it is not necessarily obeyed in condensed matter physics, and thus Lorentz-violating type-II Weyl/Dirac fermions could be realized in topological semimetals. The recent realization of type-II Weyl fermions raises the question whether their spin-degenerate counterpart-type-II Dirac fermions-can be experimentally realized too. Here, we report the experimental evidence of type-II Dirac fermions in bulk stoichiometric PtTe 2 single crystal. Angle-resolved photoemission spectroscopy measurements and first-principles calculations reveal a pair of strongly tilted Dirac cones along the Γ-A direction, confirming PtTe 2 as a type-II Dirac semimetal. Our results provide opportunities for investigating novel quantum phenomena (e.g., anisotropic magneto-transport) and topological phase transition.Whether the spin-degenerate counterpart of Lorentz-violating Weyl fermions, the Dirac fermions, can be realized remains as an open question. Here, Yan et al. report experimental evidence of such type-II Dirac fermions in bulk PtTe 2 single crystal with a pair of strongly tilted Dirac cones.
Asymptotic structure of N=2 supergravity in 3D: extended super-BMS3 and nonlinear energy bounds
NASA Astrophysics Data System (ADS)
Fuentealba, Oscar; Matulich, Javier; Troncoso, Ricardo
2017-09-01
The asymptotically flat structure of N=(2,0) supergravity in three spacetime dimensions is explored. The asymptotic symmetries are found to be spanned by an extension of the super-BMS3 algebra, endowed with two independent affine û(1) currents of electric and magnetic type. These currents are associated to U(1) fields being even and odd under parity, respectively. Remarkably, although the U(1) fields do not generate a backreaction on the metric, they provide nontrivial Sugawara-like contributions to the BMS3 generators, and hence to the energy and the angular momentum. Consequently, the entropy of flat cosmological spacetimes endowed with U(1) fields acquires a nontrivial dependence on the zero modes of the û(1) charges. If the spin structure is odd, the ground state corresponds to Minkowski spacetime, and although the anticommutator of the canonical supercharges is linear in the energy and in the electric-like û(1) charge, the energy becomes bounded from below by the energy of the ground state shifted by the square of the electric-like û(1) charge. If the spin structure is even, the same bound for the energy generically holds, unless the absolute value of the electric-like charge is less than minus the mass of Minkowski spacetime in vacuum, so that the energy has to be nonnegative. The explicit form of the global and asymptotic Killing spinors is found for a wide class of configurations that fulfills our boundary conditions, and they exist precisely when the corresponding bounds are saturated. It is also shown that the spectra with periodic or antiperiodic boundary conditions for the fermionic fields are related by spectral flow, in a similar way as it occurs for the N=2 super-Virasoro algebra. Indeed, our supersymmetric extension of BMS3 can be recovered from the Inönü-Wigner contraction of the superconformal algebra with N=(2,2) , once the fermionic generators of the right copy are truncated.
Scenarios of physics beyond the standard model
NASA Astrophysics Data System (ADS)
Fok, Ricky
This dissertation discusses three topics on scenarios beyond the Standard Model. Topic one is the effects from a fourth generation of quarks and leptons on electroweak baryogenesis in the early universe. The Standard Model is incapable of electroweak baryogenesis due to an insufficiently strong enough electroweak phase transition (EWPT) as well as insufficient CP violation. We show that the presence of heavy fourth generation fermions solves the first problem but requires additional bosons to be included to stabilize the electroweak vacuum. Introducing supersymmetric partners of the heavy fermions, we find that the EWPT can be made strong enough and new sources of CP violation are present. Topic two relates to the lepton avor problem in supersymmetry. In the Minimal Supersymmetric Standard Model (MSSM), the off-diagonal elements in the slepton mass matrix must be suppressed at the 10-3 level to avoid experimental bounds from lepton avor changing processes. This dissertation shows that an enlarged R-parity can alleviate the lepton avor problem. An analysis of all sensitive parameters was performed in the mass range below 1 TeV, and we find that slepton maximal mixing is possible without violating bounds from the lepton avor changing processes: mu → egamma; mu → e conversion, and mu → 3e. Topic three is the collider phenomenology of quirky dark matter. In this model, quirks are particles that are gauged under the electroweak group, as well as a dark" color SU(2) group. The hadronization scale of this color group is well below the quirk masses. As a result, the dark color strings never break. Quirk and anti-quirk pairs can be produced at the LHC. Once produced, they immediately form a bound state of high angular momentum. The quirk pair rapidly shed angular momentum by emitting soft radiation before they annihilate into observable signals. This dissertation presents the decay branching ratios of quirkonia where quirks obtain their masses through electroweak symmetry breaking. This dissertation includes previously published and unpublished co-authored material.
Anomaly-free dark matter models are not so simple
NASA Astrophysics Data System (ADS)
Ellis, John; Fairbairn, Malcolm; Tunney, Patrick
2017-08-01
We explore the anomaly-cancellation constraints on simplified dark matter (DM) models with an extra U(1)' gauge boson Z '. We show that, if the Standard Model (SM) fermions are supplemented by a single DM fermion χ that is a singlet of the SM gauge group, and the SM quarks have non-zero U(1)' charges, the SM leptons must also have non-zero U(1)' charges, in which case LHC searches impose strong constraints on the Z ' mass. Moreover, the DM fermion χ must have a vector-like U(1)' coupling. If one requires the DM particle to have a purely axial U(1)' coupling, which would be the case if χ were a Majorana fermion and would reduce the impact of direct DM searches, the simplest possibility is that it is accompanied by one other new singlet fermion, but in this case the U(1)' charges of the SM leptons still do not vanish. This is also true in a range of models with multiple new singlet fermions with identical charges. Searching for a leptophobic model, we then introduce extra fermions that transform non-trivially under the SM gauge group. We find several such models if the DM fermion is accompanied by two or more other new fermions with non-identical charges, which may have interesting experimental signatures. We present benchmark representatives of the various model classes we discuss.
Phase space methods for Majorana fermions
NASA Astrophysics Data System (ADS)
Rushin Joseph, Ria; Rosales-Zárate, Laura E. C.; Drummond, Peter D.
2018-06-01
Fermionic phase space representations are a promising method for studying correlated fermion systems. The fermionic Q-function and P-function have been defined using Gaussian operators of fermion annihilation and creation operators. The resulting phase-space of covariance matrices belongs to the symmetry class D, one of the non-standard symmetry classes. This was originally proposed to study mesoscopic normal-metal-superconducting hybrid structures, which is the type of structure that has led to recent experimental observations of Majorana fermions. Under a unitary transformation, it is possible to express these Gaussian operators using real anti-symmetric matrices and Majorana operators, which are much simpler mathematical objects. We derive differential identities involving Majorana fermion operators and an antisymmetric matrix which are relevant to the derivation of the corresponding Fokker–Planck equations on symmetric space. These enable stochastic simulations either in real or imaginary time. This formalism has direct relevance to the study of fermionic systems in which there are Majorana type excitations, and is an alternative to using expansions involving conventional Fermi operators. The approach is illustrated by showing how a linear coupled Hamiltonian as used to study topological excitations can be transformed to Fokker–Planck and stochastic equation form, including dissipation through particle losses.
Super-sensitive phase estimation with coherent boosted light using parity measurements
NASA Astrophysics Data System (ADS)
Xu, Lan; Tan, Qing-Shou
2018-01-01
Not Available Project supported by the National Natural Science Foundation of China (Grant No. 11665010), the Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, China (Grant No. QSQC1414), and the Scientific Research Fund of Hunan Provincial Education Department, China (Grant No. 17B055).
NASA Astrophysics Data System (ADS)
Nafaa Gaafer, Fatma; Shen, Yaxi; Peng, Yugui; Wu, Aimin; Zhang, Peng; Zhu, Xuefeng
2017-06-01
Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 11674119, 11404125, and 11574389). X. F. Z acknowledges the financial support from the Bird Nest Plan of HUST, China. P. Z. is supported by One Hundred-Talent Plan of Chinese Academy of Sciences.
Implication of Tsallis entropy in the Thomas–Fermi model for self-gravitating fermions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ourabah, Kamel; Tribeche, Mouloud, E-mail: mouloudtribeche@yahoo.fr
The Thomas–Fermi approach for self-gravitating fermions is revisited within the theoretical framework of the q-statistics. Starting from the q-deformation of the Fermi–Dirac distribution function, a generalized Thomas–Fermi equation is derived. It is shown that the Tsallis entropy preserves a scaling property of this equation. The q-statistical approach to Jeans’ instability in a system of self-gravitating fermions is also addressed. The dependence of the Jeans’ wavenumber (or the Jeans length) on the parameter q is traced. It is found that the q-statistics makes the Fermionic system unstable at scales shorter than the standard Jeans length. -- Highlights: •Thomas–Fermi approach for self-gravitatingmore » fermions. •A generalized Thomas–Fermi equation is derived. •Nonextensivity preserves a scaling property of this equation. •Nonextensive approach to Jeans’ instability of self-gravitating fermions. •It is found that nonextensivity makes the Fermionic system unstable at shorter scales.« less
Review of Physics Results from the Tevatron: Higgs Boson Physics
Junk, Thomas R.; Juste, Aurelio
2015-02-17
We review the techniques and results of the searches for the Higgs boson performed by the two Tevatron collaborations, CDF and DØ. The Higgs boson predicted by the Standard Model was sought in the mass range 90 GeV < m H < 200 GeV in all main production modes at the Tevatron: gluon–gluon fusion, WH and ZH associated production, vector boson fusion, and tt - H production, and in five main decay modes: H→ bb -, H→τ +τ -, H→WW (*), H→ZZ (*) and H→γγ. An excess of events was seen in the H→ bb - searches consistent with amore » Standard Model Higgs boson with a mass in the range 115 GeV < m H < 135 GeV. We assume a Higgs boson mass of m H = 125 GeV, studies of Higgs boson properties were performed, including measurements of the product of the cross section times the branching ratio in various production and decay modes, constraints on Higgs boson couplings to fermions and vector bosons, and tests of spin and parity. We also summarize the results of searches for supersymmetric Higgs bosons, and Higgs bosons in other extensions of the Standard Model.« less
Quantum transport in coupled Majorana box systems
NASA Astrophysics Data System (ADS)
Gau, Matthias; Plugge, Stephan; Egger, Reinhold
2018-05-01
We present a theoretical analysis of low-energy quantum transport in coupled Majorana box devices. A single Majorana box represents a Coulomb-blockaded mesoscopic superconductor proximitizing two or more long topological nanowires. The box thus harbors at least four Majorana zero modes (MZMs). Setups with several Majorana boxes, where MZMs on different boxes are tunnel coupled via short nanowire segments, are key ingredients to recent Majorana qubit and code network proposals. We construct and study the low-energy theory for multiterminal junctions with normal leads connected to the coupled box device by lead-MZM tunnel contacts. Transport experiments in such setups can test the nonlocality of Majorana-based systems and the integrity of the underlying Majorana qubits. For a single box, we recover the previously described topological Kondo effect which can be captured by a purely bosonic theory. For several coupled boxes, however, nonconserved local fermion parities require the inclusion of additional local sets of Pauli operators. We present a renormalization group analysis and develop a nonperturbative strong-coupling approach to quantum transport in such systems. Our findings are illustrated for several examples, including a loop qubit device and different two-box setups.
Dynamic origins of fermionic D -terms
NASA Astrophysics Data System (ADS)
Hudson, Jonathan; Schweitzer, Peter
2018-03-01
The D -term is defined through matrix elements of the energy-momentum tensor, similarly to mass and spin, yet this important particle property is experimentally not known any fermion. In this work we show that the D -term of a spin 1/2 fermion is of dynamical origin: it vanishes for a free fermion. This is in pronounced contrast to the bosonic case where already a free spin-0 boson has a non-zero intrinsic D -term. We illustrate in two simple models how interactions generate the D -term of a fermion with an internal structure, the nucleon. All known matter is composed of elementary fermions. This indicates the importance to study this interesting particle property in more detail, which will provide novel insights especially on the structure of the nucleon.
Superfluid and Insulating Phases of Fermion Mixtures in Optical Lattices
DOE Office of Scientific and Technical Information (OSTI.GOV)
Iskin, M.; Sa de Melo, C. A. R.
2007-08-24
The ground state phase diagram of fermion mixtures in optical lattices is analyzed as a function of interaction strength, fermion filling factor, and tunneling parameters. In addition to standard superfluid, phase-separated or coexisting superfluid-excess-fermion phases found in homogeneous or harmonically trapped systems, fermions in optical lattices have several insulating phases, including a molecular Bose-Mott insulator (BMI), a Fermi-Pauli (band) insulator (FPI), a phase-separated BMI-FPI mixture or a Bose-Fermi checkerboard (BFC). The molecular BMI phase is the fermion mixture counterpart of the atomic BMI found in atomic Bose systems, the BFC or BMI-FPI phases exist in Bose-Fermi mixtures, and lastly themore » FPI phase is particular to the Fermi nature of the constituent atoms of the mixture.« less
Phenomenology of fermion production during axion inflation
NASA Astrophysics Data System (ADS)
Adshead, Peter; Pearce, Lauren; Peloso, Marco; Roberts, Michael A.; Sorbo, Lorenzo
2018-06-01
We study the production of fermions through a derivative coupling with a pseudoscalar inflaton and the effects of the produced fermions on the scalar primordial perturbations. We present analytic results for the modification of the scalar power spectrum due to the produced fermions, and we estimate the amplitude of the non-Gaussianities in the equilateral regime. Remarkably, we find a regime where the effect of the fermions gives the dominant contribution to the scalar spectrum while the amplitude of the bispectrum is small and in agreement with observation. We also note the existence of a regime in which the backreaction of the fermions on the evolution of the zero-mode of the inflaton can lead to inflation even if the potential of the inflaton is steep and does not satisfy the slow-roll conditions.
Large linear magnetoresistance in a new Dirac material BaMnBi2
NASA Astrophysics Data System (ADS)
Wang, Yi-Yan; Yu, Qiao-He; Xia, Tian-Long
2016-10-01
Dirac semimetal is a class of materials that host Dirac fermions as emergent quasi-particles. Dirac cone-type band structure can bring interesting properties such as quantum linear magnetoresistance and large mobility in the materials. In this paper, we report the synthesis of high quality single crystals of BaMnBi2 and investigate the transport properties of the samples. BaMnBi2 is a metal with an antiferromagnetic transition at T N = 288 K. The temperature dependence of magnetization displays different behavior from CaMnBi2 and SrMnBi2, which suggests the possible different magnetic structure of BaMnBi2. The Hall data reveals electron-type carriers and a mobility μ(5 K) = 1500 cm2/V·s. Angle-dependent magnetoresistance reveals the quasi-two-dimensional (2D) Fermi surface in BaMnBi2. A crossover from semiclassical MR ˜ H 2 dependence in low field to MR ˜ H dependence in high field, which is attributed to the quantum limit of Dirac fermions, has been observed in magnetoresistance. Our results indicate the existence of Dirac fermions in BaMnBi2. Project supported by the National Natural Science Foundation of China (Grant No. 11574391), the Fundamental Research Funds for the Central Universities, and the Research Funds of Renmin University of China (Grant No. 14XNLQ07).
On the regularized fermionic projector of the vacuum
NASA Astrophysics Data System (ADS)
Finster, Felix
2008-03-01
We construct families of fermionic projectors with spherically symmetric regularization, which satisfy the condition of a distributional MP-product. The method is to analyze regularization tails with a power law or logarithmic scaling in composite expressions in the fermionic projector. The resulting regularizations break the Lorentz symmetry and give rise to a multilayer structure of the fermionic projector near the light cone. Furthermore, we construct regularizations which go beyond the distributional MP-product in that they yield additional distributional contributions supported at the origin. The remaining freedom for the regularization parameters and the consequences for the normalization of the fermionic states are discussed.
Semiclassical fermion pair creation in de Sitter spacetime
DOE Office of Scientific and Technical Information (OSTI.GOV)
Stahl, Clément, E-mail: clement.stahl@icranet.org; Eckhard, Strobel, E-mail: eckhard.strobel@irap-phd.eu; Dipartimento di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome
2015-12-17
We present a method to semiclassically compute the pair creation rate of bosons and fermions in de Sitter spacetime. The results in the bosonic case agree with the ones in the literature. We find that for the constant electric field the fermionic and bosonic pair creation rate are the same. This analogy of bosons and fermions in the semiclassical limit is known from several flat spacetime examples.
Perturbative quantum field theory in the framework of the fermionic projector
NASA Astrophysics Data System (ADS)
Finster, Felix
2014-04-01
We give a microscopic derivation of perturbative quantum field theory, taking causal fermion systems and the framework of the fermionic projector as the starting point. The resulting quantum field theory agrees with standard quantum field theory on the tree level and reproduces all bosonic loop diagrams. The fermion loops are described in a different formalism in which no ultraviolet divergences occur.
NASA Astrophysics Data System (ADS)
Shifman, M.; Yung, A.
2018-03-01
Non-Abelian strings are considered in non-supersymmetric theories with fermions in various appropriate representations of the gauge group U(N). We derive the electric charge quantization conditions and the index theorems counting fermion zero modes in the string background both for the left-handed and right-handed fermions. In both cases we observe a non-trivial N dependence.
Topology and strong four fermion interactions in four dimensions
NASA Astrophysics Data System (ADS)
Catterall, Simon; Butt, Nouman
2018-05-01
We study massless fermions interacting through a particular four-fermion term in four dimensions. Exact symmetries prevent the generation of bilinear fermion mass terms. We determine the structure of the low-energy effective action for the auxiliary field needed to generate the four-fermion term and find it has an novel structure that admits topologically nontrivial defects with nonzero Hopf invariant. We show that fermions propagating in such a background pick up a mass without breaking symmetries. Furthermore, pairs of such defects experience a logarithmic interaction. We argue that a phase transition separates a phase where these defects proliferate from a broken phase where they are bound tightly. We conjecture that, by tuning one additional operator, the broken phase can be eliminated with a single BKT-like phase transition separating the massless from massive phases.
Chen, Hua-Jun; Zhu, Ka-Di
2015-01-01
In the present work, we theoretically propose an optical scheme to detect the possible signature of Majorana fermions via the optical pump-probe spectroscopy, which is very different from the current tunneling measurement based on electrical methods. The scheme consists of a metal nanoparticle and a semiconductor quantum dot coupled to a hybrid semiconductor/superconductor heterostructures. The results show that the probe absorption spectrum of the quantum dot presents a distinct splitting due to the existence of Majorana fermions. Owing to surface plasmon enhanced effect, this splitting will be more obvious, which makes Majorana fermions more easy to be detectable. The technique proposed here open the door for new applications ranging from robust manipulation of Majorana fermions to quantum information processing based on Majorana fermions. PMID:26310929
Cosmological singularities and bounce in Cartan-Einstein theory
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lucat, Stefano; Prokopec, Tomislav, E-mail: s.lucat@students.uu.nl, E-mail: t.prokopec@uu.nl
We consider a generalized Einstein-Cartan theory, in which we add the unique covariant dimension four operators to general relativity that couples fermionic spin current to the torsion tensor (with an arbitrary strength). Since torsion is local and non-dynamical, when integrated out it yields an effective four-fermion interaction of the gravitational strength. We show how to renormalize the theory, in the one-loop perturbative expansion in generally curved space-times, obtaining the first order correction to the 2PI effective action in Schwinger-Keldysh ( in-in ) formalism. We then apply the renormalized theory to study the dynamics of a collapsing universe that begins inmore » a thermal state and find that—instead of a big crunch singularity—the Universe with torsion undergoes a bounce . We solve the dynamical equations (a) classically (without particle production); (b) including the production of fermions in a fixed background in the Hartree-Fock approximation and (c) including the quantum backreaction of fermions onto the background space-time. In the first and last cases the Universe undergoes a bounce. The production of fermions due to the coupling to a contracting homogeneous background speeds up the bounce, implying that the quantum contributions from fermions is negative, presumably because fermion production contributes negatively to the energy-momentum tensor. When compared with former works on the subject, our treatment is fully microscopic (namely, we treat fermions by solving the corresponding Dirac equations) and quantum (in the sense that we include fermionic loop contributions).« less
Cosmological singularities and bounce in Cartan-Einstein theory
NASA Astrophysics Data System (ADS)
Lucat, Stefano; Prokopec, Tomislav
2017-10-01
We consider a generalized Einstein-Cartan theory, in which we add the unique covariant dimension four operators to general relativity that couples fermionic spin current to the torsion tensor (with an arbitrary strength). Since torsion is local and non-dynamical, when integrated out it yields an effective four-fermion interaction of the gravitational strength. We show how to renormalize the theory, in the one-loop perturbative expansion in generally curved space-times, obtaining the first order correction to the 2PI effective action in Schwinger-Keldysh (in-in) formalism. We then apply the renormalized theory to study the dynamics of a collapsing universe that begins in a thermal state and find that—instead of a big crunch singularity—the Universe with torsion undergoes a bounce. We solve the dynamical equations (a) classically (without particle production); (b) including the production of fermions in a fixed background in the Hartree-Fock approximation and (c) including the quantum backreaction of fermions onto the background space-time. In the first and last cases the Universe undergoes a bounce. The production of fermions due to the coupling to a contracting homogeneous background speeds up the bounce, implying that the quantum contributions from fermions is negative, presumably because fermion production contributes negatively to the energy-momentum tensor. When compared with former works on the subject, our treatment is fully microscopic (namely, we treat fermions by solving the corresponding Dirac equations) and quantum (in the sense that we include fermionic loop contributions).
LHC accessible second Higgs boson in the left-right model
NASA Astrophysics Data System (ADS)
Mohapatra, Rabindra N.; Zhang, Yongchao
2014-03-01
A second Higgs doublet arises naturally as a parity partner of the standard model (SM) Higgs, once the SM is extended to its left-right symmetric version (LRSM) to understand the origin of parity violation in weak interactions, as well as to accommodate small neutrino masses via the seesaw mechanism. The flavor-changing neutral Higgs (FCNH) effects in the minimal version of this model (LRSM), however, push the second Higgs mass to more than 15 TeV, making it inaccessible at the LHC. Furthermore, since the second Higgs mass is directly linked to the WR mass, discovery of a "low" mass WR (MWR≤5-6 TeV) at the LHC would require values for some Higgs self-couplings larger than 1. In this paper we present an extension of LRSM by adding a vectorlike SU(2)R quark doublet which weakens the FCNH constraints, allowing the second Higgs mass to be near or below the TeV range and a third neutral Higgs below 3 TeV for a WR mass below 5 TeV. It is then possible to search for these heavier Higgs bosons at the LHC without conflicting with FCNH constraints. A right-handed WR mass in the few TeV range is quite natural in this class of models without having to resort to large scalar coupling parameters. The CKM mixings are intimately linked to the vectorlike quark mixings with the known quarks, which is the main reason why the constraints on the second Higgs mass are relaxed. We present a detailed theoretical and phenomenological analysis of this extended left-right model and point out some tests as well as its potential for discovery of a second Higgs at the LHC. Two additional features of the model are a 5/3-charged quark and a fermionic top partner with masses in the TeV range.
Fermion systems in discrete space-time
NASA Astrophysics Data System (ADS)
Finster, Felix
2007-05-01
Fermion systems in discrete space-time are introduced as a model for physics on the Planck scale. We set up a variational principle which describes a non-local interaction of all fermions. This variational principle is symmetric under permutations of the discrete space-time points. We explain how for minimizers of the variational principle, the fermions spontaneously break this permutation symmetry and induce on space-time a discrete causal structure.
New chiral fermions, a new gauge interaction, Dirac neutrinos, and dark matter
de Gouvea, Andre; Hernandez, Daniel
2015-10-07
Here, we propose that all light fermionic degrees of freedom, including the Standard Model (SM) fermions and all possible light beyond-the-standard-model fields, are chiral with respect to some spontaneously broken abelian gauge symmetry. Hypercharge, for example, plays this role for the SM fermions. We introduce a new symmetry, U(1) ν , for all new light fermionic states. Anomaly cancellations mandate the existence of several new fermion fields with nontrivial U(1) ν charges. We develop a concrete model of this type, for which we show that (i) some fermions remain massless after U(1) ν breaking — similar to SM neutrinos —more » and (ii) accidental global symmetries translate into stable massive particles — similar to SM protons. These ingredients provide a solution to the dark matter and neutrino mass puzzles assuming one also postulates the existence of heavy degrees of freedom that act as “mediators” between the two sectors. The neutrino mass mechanism described here leads to parametrically small Dirac neutrino masses, and the model also requires the existence of at least four Dirac sterile neutrinos. Finally, we describe a general technique to write down chiral-fermions-only models that are at least anomaly-free under a U(1) gauge symmetry.« less
New chiral fermions, a new gauge interaction, Dirac neutrinos, and dark matter
DOE Office of Scientific and Technical Information (OSTI.GOV)
de Gouvea, Andre; Hernandez, Daniel
Here, we propose that all light fermionic degrees of freedom, including the Standard Model (SM) fermions and all possible light beyond-the-standard-model fields, are chiral with respect to some spontaneously broken abelian gauge symmetry. Hypercharge, for example, plays this role for the SM fermions. We introduce a new symmetry, U(1) ν , for all new light fermionic states. Anomaly cancellations mandate the existence of several new fermion fields with nontrivial U(1) ν charges. We develop a concrete model of this type, for which we show that (i) some fermions remain massless after U(1) ν breaking — similar to SM neutrinos —more » and (ii) accidental global symmetries translate into stable massive particles — similar to SM protons. These ingredients provide a solution to the dark matter and neutrino mass puzzles assuming one also postulates the existence of heavy degrees of freedom that act as “mediators” between the two sectors. The neutrino mass mechanism described here leads to parametrically small Dirac neutrino masses, and the model also requires the existence of at least four Dirac sterile neutrinos. Finally, we describe a general technique to write down chiral-fermions-only models that are at least anomaly-free under a U(1) gauge symmetry.« less
String theory, quantum phase transitions, and the emergent Fermi liquid.
Cubrović, Mihailo; Zaanen, Jan; Schalm, Koenraad
2009-07-24
A central problem in quantum condensed matter physics is the critical theory governing the zero-temperature quantum phase transition between strongly renormalized Fermi liquids as found in heavy fermion intermetallics and possibly in high-critical temperature superconductors. We found that the mathematics of string theory is capable of describing such fermionic quantum critical states. Using the anti-de Sitter/conformal field theory correspondence to relate fermionic quantum critical fields to a gravitational problem, we computed the spectral functions of fermions in the field theory. By increasing the fermion density away from the relativistic quantum critical point, a state emerges with all the features of the Fermi liquid.
Bosonization of fermions coupled to topologically massive gravity
NASA Astrophysics Data System (ADS)
Fradkin, Eduardo; Moreno, Enrique F.; Schaposnik, Fidel A.
2014-03-01
We establish a duality between massive fermions coupled to topologically massive gravity (TMG) in d=3 space-time dimensions and a purely gravity theory which also will turn out to be a TMG theory but with different parameters: the original graviton mass in the TMG theory coupled to fermions picks up a contribution from fermion bosonization. We obtain explicit bosonization rules for the fermionic currents and for the energy-momentum tensor showing that the identifications do not depend explicitly on the parameters of the theory. These results are the gravitational analog of the results for 2+1 Abelian and non-Abelian bosonization in flat space-time.
A four-dimensional model with the fermionic determinant exactly evaluated
NASA Astrophysics Data System (ADS)
Mignaco, J. A.; Rego Monteiro, M. A.
1986-07-01
A method is presented to compute the fermion determinant of some class of field theories. By this method the following results of the fermion determinant in two dimensions are easily recovered: (i) Schwinger model without reference to a particular gauge. (ii) QCD in the light-cone gauge. (iii) Gauge invariant result of QCD. The method is finally applied to give an analytical solution of the fermion determinant of a four-dimensional, non-abelian, Dirac-like theory with massless fermions interacting with an external vector field through a pseudo-vectorial coupling. Fellow of the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brazil.
Jia, Shaoyang; Pennington, M. R.
2017-08-01
With the introduction of a spectral representation, the Schwinger-Dyson equation (SDE) for the fermion propagator is formulated in Minkowski space in QED. After imposing the on-shell renormalization conditions, analytic solutions for the fermion propagator spectral functions are obtained in four dimensions with a renormalizable version of the Gauge Technique anzatz for the fermion-photon vertex in the quenched approximation in the Landau gauge. Despite the limitations of this model, having an explicit solution provides a guiding example of the fermion propagator with the correct analytic structure. The Padé approximation for the spectral functions is also investigated.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jia, Shaoyang; Pennington, M. R.
With the introduction of a spectral representation, the Schwinger-Dyson equation (SDE) for the fermion propagator is formulated in Minkowski space in QED. After imposing the on-shell renormalization conditions, analytic solutions for the fermion propagator spectral functions are obtained in four dimensions with a renormalizable version of the Gauge Technique anzatz for the fermion-photon vertex in the quenched approximation in the Landau gauge. Despite the limitations of this model, having an explicit solution provides a guiding example of the fermion propagator with the correct analytic structure. The Padé approximation for the spectral functions is also investigated.
Constructing the AdS dual of a Fermi liquid: AdS black holes with Dirac hair
NASA Astrophysics Data System (ADS)
Čubrović, Mihailo; Zaanen, Jan; Schalm, Koenraad
2011-10-01
We provide evidence that the holographic dual to a strongly coupled charged Fermi liquid has a non-zero fermion density in the bulk. We show that the pole-strength of the stable quasiparticle characterizing the Fermi surface is encoded in the AdS probability density of a single normalizable fermion wavefunction in AdS. Recalling Migdal's theorem which relates the pole strength to the Fermi-Dirac characteristic discontinuity in the number density at ω F , we conclude that the AdS dual of a Fermi liquid is described by occupied on-shell fermionic modes in AdS. Encoding the occupied levels in the total spatially averaged probability density of the fermion field directly, we show that an AdS Reissner-Nordström black holein a theory with charged fermions has a critical temperature, at which the system undergoes a first-order transition to a black hole with a non-vanishing profile for the bulk fermion field. Thermodynamics and spectral analysis support that the solution with non-zero AdS fermion-profile is the preferred ground state at low temperatures.
Effective interaction of electroweak-interacting dark matter with Higgs boson and its phenomenology
NASA Astrophysics Data System (ADS)
Hisano, Junji; Kobayashi, Daiki; Mori, Naoya; Senaha, Eibun
2015-03-01
We study phenomenology of electroweak-interacting fermionic dark matter (DM) with a mass of O (100) GeV. Constructing the effective Lagrangian that describes the interactions between the Higgs boson and the SU (2)L isospin multiplet fermion, we evaluate the electric dipole moment (EDM) of electron, the signal strength of Higgs boson decay to two photons and the spin-independent elastic-scattering cross section with proton. As representative cases, we consider the SU (2)L triplet fermions with zero/nonzero hypercharges and SU (2)L doublet fermion. It is found that the electron EDM gives stringent constraints on those model parameter spaces. In the cases of the triplet fermion with zero hypercharge and the doublet fermion, the Higgs signal strength does not deviate from the standard model prediction by more than a few % once the current DM direct detection constraint is taken into account, even if the CP violation is suppressed. On the contrary, O (10- 20)% deviation may occur in the case of the triplet fermion with nonzero hypercharge. Our representative scenarios may be tested by the future experiments.
The Weak Charge of the Proton. A Search For Physics Beyond the Standard Model
DOE Office of Scientific and Technical Information (OSTI.GOV)
MacEwan, Scott J.
2015-05-01
The Q weak experiment, which completed running in May of 2012 at Jefferson Laboratory, has measured the parity-violating asymmetry in elastic electron-proton scattering at four-momentum transfer Q 2 =0.025 (GeV/c) 2 in order to provide the first direct measurement of the proton's weak charge, Q W p. The Standard Model makes firm predictions for the weak charge; deviations from the predicted value would provide strong evidence of new physics beyond the Standard Model. Using an 89% polarized electron beam at 145 microA scattering from a 34.4 cm long liquid hydrogen target, scattered electrons were detected using an array of eightmore » fused-silica detectors placed symmetric about the beam axis. The parity-violating asymmetry was then measured by reversing the helicity of the incoming electrons and measuring the normalized difference in rate seen in the detectors. The low Q 2 enables a theoretically clean measurement; the higher-order hadronic corrections are constrained using previous parity-violating electron scattering world data. The experimental method will be discussed, with recent results constituting 4% of our total data and projections of our proposed uncertainties on the full data set.« less
Majorana-Based Fermionic Quantum Computation.
O'Brien, T E; Rożek, P; Akhmerov, A R
2018-06-01
Because Majorana zero modes store quantum information nonlocally, they are protected from noise, and have been proposed as a building block for a quantum computer. We show how to use the same protection from noise to implement universal fermionic quantum computation. Our architecture requires only two Majorana modes to encode a fermionic quantum degree of freedom, compared to alternative implementations which require a minimum of four Majorana modes for a spin quantum degree of freedom. The fermionic degrees of freedom support both unitary coupled cluster variational quantum eigensolver and quantum phase estimation algorithms, proposed for quantum chemistry simulations. Because we avoid the Jordan-Wigner transformation, our scheme has a lower overhead for implementing both of these algorithms, allowing for simulation of the Trotterized Hubbard Hamiltonian in O(1) time per unitary step. We finally demonstrate magic state distillation in our fermionic architecture, giving a universal set of topologically protected fermionic quantum gates.
Observing fermionic statistics with photons in arbitrary processes
Matthews, Jonathan C. F.; Poulios, Konstantinos; Meinecke, Jasmin D. A.; Politi, Alberto; Peruzzo, Alberto; Ismail, Nur; Wörhoff, Kerstin; Thompson, Mark G.; O'Brien, Jeremy L.
2013-01-01
Quantum mechanics defines two classes of particles-bosons and fermions-whose exchange statistics fundamentally dictate quantum dynamics. Here we develop a scheme that uses entanglement to directly observe the correlated detection statistics of any number of fermions in any physical process. This approach relies on sending each of the entangled particles through identical copies of the process and by controlling a single phase parameter in the entangled state, the correlated detection statistics can be continuously tuned between bosonic and fermionic statistics. We implement this scheme via two entangled photons shared across the polarisation modes of a single photonic chip to directly mimic the fermion, boson and intermediate behaviour of two-particles undergoing a continuous time quantum walk. The ability to simulate fermions with photons is likely to have applications for verifying boson scattering and for observing particle correlations in analogue simulation using any physical platform that can prepare the entangled state prescribed here. PMID:23531788
Majorana-Based Fermionic Quantum Computation
NASA Astrophysics Data System (ADS)
O'Brien, T. E.; RoŻek, P.; Akhmerov, A. R.
2018-06-01
Because Majorana zero modes store quantum information nonlocally, they are protected from noise, and have been proposed as a building block for a quantum computer. We show how to use the same protection from noise to implement universal fermionic quantum computation. Our architecture requires only two Majorana modes to encode a fermionic quantum degree of freedom, compared to alternative implementations which require a minimum of four Majorana modes for a spin quantum degree of freedom. The fermionic degrees of freedom support both unitary coupled cluster variational quantum eigensolver and quantum phase estimation algorithms, proposed for quantum chemistry simulations. Because we avoid the Jordan-Wigner transformation, our scheme has a lower overhead for implementing both of these algorithms, allowing for simulation of the Trotterized Hubbard Hamiltonian in O (1 ) time per unitary step. We finally demonstrate magic state distillation in our fermionic architecture, giving a universal set of topologically protected fermionic quantum gates.
Orientifolding of the ABJ Fermi gas
NASA Astrophysics Data System (ADS)
Okuyama, Kazumi
2016-03-01
The grand partition functions of ABJ theory can be factorized into even and odd parts under the reflection of fermion coordinate in the Fermi gas approach. In some cases, the even/odd part of ABJ grand partition function is equal to that of {N}=5O(n)× USp({n}^') theory, hence it is natural to think of the even/odd projection of grand partition function as an orientifolding of ABJ Fermi gas system. By a systematic WKB analysis, we determine the coefficients in the perturbative part of grand potential of such orientifold ABJ theory. We also find the exact form of the first few "half-instanton" corrections coming from the twisted sector of the reflection of fermion coordinate. For the Chern-Simons level k = 2 ,4 ,8 we find closed form expressions of the grand partition functions of orientifold ABJ theory, and for k = 2 , 4 we prove the functional relations among the grand partition functions conjectured in arXiv:1410.7658.
Imaging electronic states on topological semimetals using scanning tunneling microscopy
Gyenis, András; Inoue, Hiroyuki; Jeon, Sangjun; ...
2016-10-18
Following the intense studies on topological insulators, significant efforts have recently been devoted to the search for gapless topological systems. These materials not only broaden the topological classification of matter but also provide a condensed matter realization of various relativistic particles and phenomena previously discussed mainly in high energy physics. Weyl semimetals host massless, chiral, low-energy excitations in the bulk electronic band structure, whereas a symmetry protected pair of Weyl fermions gives rise to massless Dirac fermions.Weemployed scanning tunneling microscopy/spectroscopy to explore the behavior of electronic states both on the surface and in the bulk of topological semimetal phases. Bymore » mapping the quasiparticle interference (QPI) and emerging Landau levels at high magnetic field in Dirac semimetals Cd 3As 2 and Na 3Bi, we observed extended Dirac-like bulk electronic bands. QPI imaged on Weyl semimetal TaAs demonstrated the predicted momentum dependent delocalization of Fermi arc surface states in the vicinity of the surface projected Weyl nodes.« less
Observation of topological states in an optical Raman lattice with ultracold fermions
NASA Astrophysics Data System (ADS)
Song, Bo; He, Chengdong; Zhang, Long; Poon, Ting Fung Jeffrey; Hajiyev, Elnur; Ren, Zejian; Seo, Bojeong; Zhang, Shanchao; Liu, Xiong-Jun; Jo, Gyu-Boong
2017-04-01
The spin-orbit coupling with cold atoms, especially in optical lattices, provides a versatile platform to investigate the intriguing topological matters. In this talk, we will present the realization of one-dimensional spin-dependent lattice dressed by the periodic Raman field. Ultracold 173Yb fermions loaded into an optical Raman lattice reveal non-trivial spin textures due to the band topology, by which we measured topological invariants and determined a topological phase transition. In addition, we explored the non-equilibrium quench dynamics between the topological and the trivial states by suddenly changing the band topology of the optical Raman lattice. The optical Raman lattice demonstrated here opens a new avenue to study the spin-orbit coupling physics and furthermore to realize novel quantum matters such as symmetry-protected topological states. Funded by Croucher Foundation and Research Grants Council (RGC) of Hong Kong (Project ECS26300014, GRF16300215, GRF16311516, and Croucher Innovation Grants); MOST (Grant No. 2016YFA0301604) and NSFC (No. 11574008).
Semi-stochastic full configuration interaction quantum Monte Carlo
NASA Astrophysics Data System (ADS)
Holmes, Adam; Petruzielo, Frank; Khadilkar, Mihir; Changlani, Hitesh; Nightingale, M. P.; Umrigar, C. J.
2012-02-01
In the recently proposed full configuration interaction quantum Monte Carlo (FCIQMC) [1,2], the ground state is projected out stochastically, using a population of walkers each of which represents a basis state in the Hilbert space spanned by Slater determinants. The infamous fermion sign problem manifests itself in the fact that walkers of either sign can be spawned on a given determinant. We propose an improvement on this method in the form of a hybrid stochastic/deterministic technique, which we expect will improve the efficiency of the algorithm by ameliorating the sign problem. We test the method on atoms and molecules, e.g., carbon, carbon dimer, N2 molecule, and stretched N2. [4pt] [1] Fermion Monte Carlo without fixed nodes: a Game of Life, death and annihilation in Slater Determinant space. George Booth, Alex Thom, Ali Alavi. J Chem Phys 131, 050106, (2009).[0pt] [2] Survival of the fittest: Accelerating convergence in full configuration-interaction quantum Monte Carlo. Deidre Cleland, George Booth, and Ali Alavi. J Chem Phys 132, 041103 (2010).
NASA Astrophysics Data System (ADS)
Kumar, Santosh; Chanderkanta; Amphawan, Angela
2016-04-01
Parity is an extra bit which is used to add in digital information to detect error at the receiver end. It can be even and odd parity. In case of even parity, the number of one's will be even included the parity and reverse in the case of odd parity. The circuit which is used to generate the parity at the transmitter side, called the parity generator and the circuit which is used to detect the parity at receiver side is called as parity checker. In this paper, an even and odd parity generator and checker circuits are designed using electro-optic effect inside lithium niobate based Mach-Zehnder Interferometers (MZIs). The MZIs structures collectively show powerful capability in switching an input optical signal to a desired output port from a collection of output ports. The paper constitutes a mathematical description of the proposed device and thereafter simulation using MATLAB. The study is verified using beam propagation method (BPM).
Chiral Majorana fermion modes in a quantum anomalous Hall insulator–superconductor structure
He, Qing Lin; Pan, Lei; Stern, Alexander L.; ...
2017-07-21
Majorana fermion is a hypothetical particle that is its own antiparticle. We report transport measurements that suggest the existence of one-dimensional chiral Majorana fermion modes in the hybrid system of a quantum anomalous Hall insulator thin film coupled with a superconductor. As the external magnetic field is swept, half-integer quantized conductance plateaus are observed at the locations of magnetization reversals, giving a distinct signature of the Majorana fermion modes. This transport signature is reproducible over many magnetic field sweeps and appears at different temperatures. This finding may open up an avenue to control Majorana fermions for implementing robust topological quantummore » computing.« less
Novel foamy origin for singlet fermion masses
NASA Astrophysics Data System (ADS)
Ellis, John; Mavromatos, Nick E.; Nanopoulos, Dimitri V.
2017-10-01
We show how masses for singlet fermions can be generated by interactions with a D-particle model of space-time foam inspired by brane theory. It has been shown previously by one of the authors (N. E. M.) that such interactions may generate dynamically small masses for charged fermions via the recoils of D-particle defects interacting with photons. In this work we consider the direct interactions of D-particle with uncharged singlet fermions such as right-handed neutrinos. Quantum fluctuations of the lattice of D-particles have massless vector (spin-one) excitations that are analogues of phonons. These mediate forces with the singlet fermions, generating large dynamical masses that may be communicated to light neutrinos via the seesaw mechanism.
Coupled kinetic equations for fermions and bosons in the relaxation-time approximation
NASA Astrophysics Data System (ADS)
Florkowski, Wojciech; Maksymiuk, Ewa; Ryblewski, Radoslaw
2018-02-01
Kinetic equations for fermions and bosons are solved numerically in the relaxation-time approximation for the case of one-dimensional boost-invariant geometry. Fermions are massive and carry baryon number, while bosons are massless. The conservation laws for the baryon number, energy, and momentum lead to two Landau matching conditions, which specify the coupling between the fermionic and bosonic sectors and determine the proper-time dependence of the effective temperature and baryon chemical potential of the system. The numerical results illustrate how a nonequilibrium mixture of fermions and bosons approaches hydrodynamic regime described by the Navier-Stokes equations with appropriate forms of the kinetic coefficients. The shear viscosity of a mixture is the sum of the shear viscosities of fermion and boson components, while the bulk viscosity is given by the formula known for a gas of fermions, however, with the thermodynamic variables characterising the mixture. Thus, we find that massless bosons contribute in a nontrivial way to the bulk viscosity of a mixture, provided fermions are massive. We further observe the hydrodynamization effect, which takes place earlier in the shear sector than in the bulk one. The numerical studies of the ratio of the longitudinal and transverse pressures show, to a good approximation, that it depends on the ratio of the relaxation and proper times only. This behavior is connected with the existence of an attractor solution for conformal systems.
Quantum Gas Microscope for Fermionic Atoms
NASA Astrophysics Data System (ADS)
Okan, Melih; Cheuk, Lawrence; Nichols, Matthew; Lawrence, Katherine; Zhang, Hao; Zwierlein, Martin
2016-05-01
Strongly interacting fermions define the properties of complex matter throughout nature, from atomic nuclei and modern solid state materials to neutron stars. Ultracold atomic Fermi gases have emerged as a pristine platform for the study of many-fermion systems. In this poster we demonstrate the realization of a quantum gas microscope for fermionic 40 K atoms trapped in an optical lattice and the recent experiments which allows one to probe strongly correlated fermions at the single atom level. We combine 3D Raman sideband cooling with high- resolution optics to simultaneously cool and image individual atoms with single lattice site resolution at a detection fidelity above 95%. The imaging process leaves the atoms predominantly in the 3D motional ground state of their respective lattice sites, inviting the implementation of a Maxwell's demon to assemble low-entropy many-body states. Single-site resolved imaging of fermions enables the direct observation of magnetic order, time resolved measurements of the spread of particle correlations, and the detection of many-fermion entanglement. NSF, AFOSR-PECASE, AFOSR-MURI on Exotic Phases of Matter, ARO-MURI on Atomtronics, ONR, a Grant from the Army Research Office with funding from the DARPA OLE program, and the David and Lucile Packard Foundation.
Emergent pseudospin-1 Maxwell fermions with a threefold degeneracy in optical lattices
NASA Astrophysics Data System (ADS)
Zhu, Yan-Qing; Zhang, Dan-Wei; Yan, Hui; Xing, Ding-Yu; Zhu, Shi-Liang
2017-09-01
The discovery of relativistic spin-1/2 fermions such as Dirac and Weyl fermions in condensed-matter or artificial systems opens a new era in modern physics. An interesting but rarely explored question is whether other relativistic spinal excitations could be realized with artificial systems. Here, we construct two- and three-dimensional tight-binding models realizable with cold fermionic atoms in optical lattices, where the low energy excitations are effectively described by the spin-1 Maxwell equations in the Hamiltonian form. These relativistic (linear dispersion) excitations with unconventional integer pseudospin, beyond the Dirac-Weyl-Majorana fermions, are an exotic kind of fermions named as Maxwell fermions. We demonstrate that the systems have rich topological features. For instance, the threefold degenerate points called Maxwell points may have quantized Berry phases and anomalous quantum Hall effects with spin-momentum locking may appear in topological Maxwell insulators in the two-dimensional lattices. In three dimensions, Maxwell points may have nontrivial monopole charges of ±2 with two Fermi arcs connecting them, and the merging of the Maxwell points leads to topological phase transitions. Finally, we propose realistic schemes for realizing the model Hamiltonians and detecting the topological properties of the emergent Maxwell quasiparticles in optical lattices.
Modeling electron fractionalization with unconventional Fock spaces.
Cobanera, Emilio
2017-08-02
It is shown that certain fractionally-charged quasiparticles can be modeled on D-dimensional lattices in terms of unconventional yet simple Fock algebras of creation and annihilation operators. These unconventional Fock algebras are derived from the usual fermionic algebra by taking roots (the square root, cubic root, etc) of the usual fermionic creation and annihilation operators. If the fermions carry non-Abelian charges, then this approach fractionalizes the Abelian charges only. In particular, the mth-root of a spinful fermion carries charge e/m and spin 1/2. Just like taking a root of a complex number, taking a root of a fermion yields a mildly non-unique result. As a consequence, there are several possible choices of quantum exchange statistics for fermion-root quasiparticles. These choices are tied to the dimensionality [Formula: see text] of the lattice by basic physical considerations. One particular family of fermion-root quasiparticles is directly connected to the parafermion zero-energy modes expected to emerge in certain mesoscopic devices involving fractional quantum Hall states. Hence, as an application of potential mesoscopic interest, I investigate numerically the hybridization of Majorana and parafermion zero-energy edge modes caused by fractionalizing but charge-conserving tunneling.
Non-thermal leptogenesis with distinct CP violation and minimal dark matter
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhou, Hang; Gu, Pei-Hong, E-mail: einsteinzh@sjtu.edu.cn, E-mail: peihong.gu@sjtu.edu.cn
We demonstrate a unified scenario for neutrino mass, baryon asymmetry, dark matter and inflation. In addition to a fermion triplet for the so-called minimal dark matter, we extend the standard model by three heavy fields including a scalar singlet, a fermion triplet and a fermion singlet/Higgs triplet. The heavy scalar singlet, which is expected to drive an inflation, and the dark matter fermion triplet are odd under an unbroken Z {sub 2} discrete symmetry, while the other fields are all even. The heavy fermion triplet offers a tree-level type-III seesaw and then mediates a three-body decay of the inflaton intomore » the standard model lepton and Higgs doublets with the dark matter fermion triplet. The heavy fermion singlet/Higgs triplet not only results in a type-I/II seesaw at tree level but also contributes to the inflaton decay at one-loop level. In this scenario, the type-I/II seesaw contains all of the physical CP phases in the lepton sector and hence the CP violation for the non-thermal leptogenesis by the inflaton decay exactly comes from the imaginary part of the neutrino mass matrix.« less
Fermion-induced quantum critical points.
Li, Zi-Xiang; Jiang, Yi-Fan; Jian, Shao-Kai; Yao, Hong
2017-08-22
A unified theory of quantum critical points beyond the conventional Landau-Ginzburg-Wilson paradigm remains unknown. According to Landau cubic criterion, phase transitions should be first-order when cubic terms of order parameters are allowed by symmetry in the Landau-Ginzburg free energy. Here, from renormalization group analysis, we show that second-order quantum phase transitions can occur at such putatively first-order transitions in interacting two-dimensional Dirac semimetals. As such type of Landau-forbidden quantum critical points are induced by gapless fermions, we call them fermion-induced quantum critical points. We further introduce a microscopic model of SU(N) fermions on the honeycomb lattice featuring a transition between Dirac semimetals and Kekule valence bond solids. Remarkably, our large-scale sign-problem-free Majorana quantum Monte Carlo simulations show convincing evidences of a fermion-induced quantum critical points for N = 2, 3, 4, 5 and 6, consistent with the renormalization group analysis. We finally discuss possible experimental realizations of the fermion-induced quantum critical points in graphene and graphene-like materials.Quantum phase transitions are governed by Landau-Ginzburg theory and the exceptions are rare. Here, Li et al. propose a type of Landau-forbidden quantum critical points induced by gapless fermions in two-dimensional Dirac semimetals.
Koketsu, Yuzo
2005-03-15
This study investigated relationships between herd age structure and herd productivity in breeding herds; it also investigated a pattern in parity proportions of females over 2 years and its relationship with herd productivity in commercial swine herds. This study was based on data from 148 commercial farms in North America stored in the swine database program at the University of Minnesota. The primary selection criterion was fluctuations in breeding-female pig (female) inventories over a 2-year interval. Productivity measurements and parity proportions of females were extracted from the database. A 24-month time-plot in proportions of Parity 0 and Parities 3-5 females (mid-parity) was charted for each farm. Using these charts, a change in proportions of Parity 0 and mid-parity for each farm was categorized into patterns: FLUCTUATE (Parity 0 and mid-parity proportion lines crossed) or STABLE (the two proportion lines never crossed). Higher proportions of mid-parity sows were correlated with greater pigs weaned per female per year (PWFY; P < 0.01). Farms with a FLUCTUATE (73% of the 148 farms) pattern had lower PWFY than those with a STABLE pattern (P < 0.01). The STABLE farms had higher proportions of mid-parity sows, higher parity at culling, higher frequency of gilt deliveries per year, and lower replacement rate than the FLUCTUATE farms (P < 0.01). In conclusion, maintaining stable subpopulations with mid-parity and Parity 0 are recommended to optimize herd productivity.
NASA Astrophysics Data System (ADS)
Sakamoto, R.; Ono, Y.; Hatsuda, R.; Shiina, K.; Arahata, E.; Mori, H.
2018-03-01
We found that a spin current of fermions could be induced in spin-orbit coupled Bose-Fermi mixture at zero temperature. Since spatial change of the spin structure of the bosons is necessary to induce the spin current of the fermions, we analyzed the ground state of the bosons in the mixture system, using a variational method. The obtained phase diagram indicated the presence of a bosonic phase that allowed the fermions to have a spin current.
Spin-Orbit Coupling and Novel Electronic States at the Interfaces of Heavy Fermion Materials
2016-02-22
idea, which is to study novel electronic phases at the interfaces of heavy fermion heterostructures. The key physics is that the strong and tunable...of Heavy Fermion Materials The views, opinions and/or findings contained in this report are those of the author(s) and should not contrued as an...ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 2D heavy fermions, quantum criticality, spin-orbit
Fermion mass without symmetry breaking
Catterall, Simon
2016-01-20
We examine a model of reduced staggered fermions in three dimensions interacting through an SO (4) invariant four fermion interaction. The model is similar to that considered in a recent paper by Ayyer and Chandrasekharan. We present theoretical arguments and numerical evidence which support the idea that the system develops a mass gap for sufficiently strong four fermi coupling without producing a symmetry breaking fermion bilinear condensate. As a result, massless and massive phases appear to be separated by a continuous phase transition.
Itinerant quantum multicriticality of two-dimensional Dirac fermions
NASA Astrophysics Data System (ADS)
Roy, Bitan; Goswami, Pallab; Juričić, Vladimir
2018-05-01
We analyze emergent quantum multicriticality for strongly interacting, massless Dirac fermions in two spatial dimensions (d =2 ) within the framework of Gross-Neveu-Yukawa models, by considering the competing order parameters that give rise to fully gapped (insulating or superconducting) ground states. We focus only on those competing orders which can be rotated into each other by generators of an exact or emergent chiral symmetry of massless Dirac fermions, and break O(S1) and O(S2) symmetries in the ordered phase. Performing a renormalization-group analysis by using the ɛ =(3 -d ) expansion scheme, we show that all the coupling constants in the critical hyperplane flow toward a new attractive fixed point, supporting an enlarged O(S1+S2) chiral symmetry. Such a fixed point acts as an exotic quantum multicritical point (MCP), governing the continuous semimetal-insulator as well as insulator-insulator (for example, antiferromagnet to valence bond solid) quantum phase transitions. In comparison with the lower symmetric semimetal-insulator quantum critical points, possessing either O(S1) or O(S2) chiral symmetry, the MCP displays enhanced correlation length exponents, and anomalous scaling dimensions for both fermionic and bosonic fields. We discuss the scaling properties of the ratio of bosonic and fermionic masses, and the increased dc resistivity at the MCP. By computing the scaling dimensions of different local fermion bilinears in the particle-hole channel, we establish that most of the four fermion operators or generalized density-density correlation functions display faster power-law decays at the MCP compared to the free fermion and lower symmetric itinerant quantum critical points. Possible generalization of this scenario to higher-dimensional Dirac fermions is also outlined.
NASA Astrophysics Data System (ADS)
Abanov, Ar.; Chubukov, Andrey V.; Schmalian, J.
2003-03-01
We present the full analysis of the normal state properties of the spin-fermion model near the antiferromagnetic instability in two dimensions. The model describes low-energy fermions interacting with their own collective spin fluctuations, which soften at the antiferromagnetic transition. We argue that in 2D, the system has two typical energies-an effective spin-fermion interaction bar g and an energy ysf below which the system behaves as a Fermi liquid. The ratio of the two determines the dimensionless coupling constant for spin-fermion interaction lambda (2) alpha /line g /omega _{sf} . We show that u scales with the spin correlation length and diverges at criticality. This divergence implies that the conventional perturbative expansion breaks down. We develop a novel approach to the problem-the expansion in either the inverse number of hot spots in the Brillouin zone, or the inverse number of fermionic flavours-which allows us to explicitly account for all terms which diverge as powers of u, and treat the remaining, O(logu) terms in the RG formalism. We apply this technique to study the properties of the spin-fermion model in various frequency and temperature regimes. We present the results for the fermionic spectral function, spin susceptibility, optical conductivity and other observables. We compare our results in detail with the normal state data for the cuprates, and argue that the spin-fermion model is capable of explaining the anomalous normal state properties of the high Tc materials. We also show that the conventional Ӓ theory of the quantum-critical behaviour is inapplicable in 2D due to the singularity of the Ӓ vertex.
Superfluid response in heavy fermion superconductors
NASA Astrophysics Data System (ADS)
Zhong, Yin; Zhang, Lan; Shao, Can; Luo, Hong-Gang
2017-10-01
Motivated by a recent London penetration depth measurement [H. Kim, et al., Phys. Rev. Lett. 114, 027003 (2015)] and novel composite pairing scenario [O. Erten, R. Flint, and P. Coleman, Phys. Rev. Lett. 114, 027002 (2015)] of the Yb-doped heavy fermion superconductor CeCoIn5, we revisit the issue of superfluid response in the microscopic heavy fermion lattice model. However, from the literature, an explicit expression for the superfluid response function in heavy fermion superconductors is rare. In this paper, we investigate the superfluid density response function in the celebrated Kondo-Heisenberg model. To be specific, we derive the corresponding formalism from an effective fermionic large- N mean-field pairing Hamiltonian whose pairing interaction is assumed to originate from the effective local antiferromagnetic exchange interaction. Interestingly, we find that the physically correct, temperature-dependent superfluid density formula can only be obtained if the external electromagnetic field is directly coupled to the heavy fermion quasi-particle rather than the bare conduction electron or local moment. Such a unique feature emphasizes the key role of the Kondo-screening-renormalized heavy quasi-particle for low-temperature/energy thermodynamics and transport behaviors. As an important application, the theoretical result is compared to an experimental measurement in heavy fermion superconductors CeCoIn5 and Yb-doped Ce1- x Yb x CoIn5 with fairly good agreement and the transition of the pairing symmetry in the latter material is explained as a simple doping effect. In addition, the requisite formalism for the commonly encountered nonmagnetic impurity and non-local electrodynamic effect are developed. Inspired by the success in explaining classic 115-series heavy fermion superconductors, we expect the present theory will be applied to understand other heavy fermion superconductors such as CeCu2Si2 and more generic multi-band superconductors.
Fermion bag approach to Hamiltonian lattice field theories in continuous time
NASA Astrophysics Data System (ADS)
Huffman, Emilie; Chandrasekharan, Shailesh
2017-12-01
We extend the idea of fermion bags to Hamiltonian lattice field theories in the continuous time formulation. Using a class of models we argue that the temperature is a parameter that splits the fermion dynamics into small spatial regions that can be used to identify fermion bags. Using this idea we construct a continuous time quantum Monte Carlo algorithm and compute critical exponents in the 3 d Ising Gross-Neveu universality class using a single flavor of massless Hamiltonian staggered fermions. We find η =0.54 (6 ) and ν =0.88 (2 ) using lattices up to N =2304 sites. We argue that even sizes up to N =10 ,000 sites should be accessible with supercomputers available today.
Amplified fermion production from overpopulated Bose fields
NASA Astrophysics Data System (ADS)
Berges, J.; Gelfand, D.; Sexty, D.
2014-01-01
We study the real-time dynamics of fermions coupled to scalar fields in a linear sigma model, which is often employed in the context of preheating after inflation or as a low-energy effective model for quantum chromodynamics. We find a dramatic amplification of fermion production in the presence of highly occupied bosonic quanta for weak as well as strong effective couplings. For this we consider the range of validity of different methods: lattice simulations with male/female fermions, the mode functions approach and the quantum 2PI effective action with its associated kinetic theory. For strongly coupled fermions we find a rapid approach to a Fermi-Dirac distribution with time-dependent temperature and chemical potential parameters, while the bosons are still far from equilibrium.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chen, Chien-Yi; Hill, Richard J.; Solon, Mikhail P.
WIMP-nucleon scattering is analyzed at ordermore » $1/M$ in Heavy WIMP Effective Theory. The $1/M$ power corrections, where $$M\\gg m_W$$ is the WIMP mass, distinguish between different underlying UV models with the same universal limit and their impact on direct detection rates can be enhanced relative to naive expectations due to generic amplitude-level cancellations at leading order. The necessary one- and two-loop matching calculations onto the low-energy effective theory for WIMP interactions with Standard Model quarks and gluons are performed for the case of an electroweak SU(2) triplet WIMP, considering both the cases of elementary fermions and composite scalars. The low-velocity WIMP-nucleon scattering cross section is evaluated and compared with current experimental limits and projected future sensitivities. Our results provide the most robust prediction for electroweak triplet Majorana fermion dark matter direct detection rates; for this case, a cancellation between two sources of power corrections yields a small total $1/M$ correction, and a total cross section close to the universal limit for $$M \\gtrsim {\\rm few} \\times 100\\,{\\rm GeV}$$. For the SU(2) composite scalar, the $1/M$ corrections introduce dependence on underlying strong dynamics. Using a leading chiral logarithm evaluation, the total $1/M$ correction has a larger magnitude and uncertainty than in the fermionic case, with a sign that further suppresses the total cross section. These examples provide definite targets for future direct detection experiments and motivate large scale detectors capable of probing to the neutrino floor in the TeV mass regime.« less
Heavy Fermion Materials and Quantum Phase Transitions Workshop on Frontiers of the Kondo Effect
2016-02-12
Stefan Kirchner (Max Planck) discussed the role of quantum criticality on the superconducting condensation in heavy-fermion superconductors , and...Collin Broholm (Johns Hopkins) discussed magnetic excitations of heavy fermion superconductors . The workshop concluded with a wide-ranging talk by
Connecting dark matter annihilation to the vertex functions of Standard Model fermions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kumar, Jason; Light, Christopher, E-mail: jkumar@hawaii.edu, E-mail: lightc@hawaii.edu
We consider scenarios in which dark matter is a Majorana fermion which couples to Standard Model fermions through the exchange of charged mediating particles. The matrix elements for various dark matter annihilation processes are then related to one-loop corrections to the fermion-photon vertex, where dark matter and the charged mediators run in the loop. In particular, in the limit where Standard Model fermion helicity mixing is suppressed, the cross section for dark matter annihilation to various final states is related to corrections to the Standard Model fermion charge form factor. These corrections can be extracted in a gauge-invariant manner frommore » collider cross sections. Although current measurements from colliders are not precise enough to provide useful constraints on dark matter annihilation, improved measurements at future experiments, such as the International Linear Collider, could improve these constraints by several orders of magnitude, allowing them to surpass the limits obtainable by direct observation.« less
Discovery of Lorentz-violating type II Weyl fermions in LaAlGe
Xu, Su-Yang; Alidoust, Nasser; Chang, Guoqing; Lu, Hong; Singh, Bahadur; Belopolski, Ilya; Sanchez, Daniel S.; Zhang, Xiao; Bian, Guang; Zheng, Hao; Husanu, Marious-Adrian; Bian, Yi; Huang, Shin-Ming; Hsu, Chuang-Han; Chang, Tay-Rong; Jeng, Horng-Tay; Bansil, Arun; Neupert, Titus; Strocov, Vladimir N.; Lin, Hsin; Jia, Shuang; Hasan, M. Zahid
2017-01-01
In quantum field theory, Weyl fermions are relativistic particles that travel at the speed of light and strictly obey the celebrated Lorentz symmetry. Their low-energy condensed matter analogs are Weyl semimetals, which are conductors whose electronic excitations mimic the Weyl fermion equation of motion. Although the traditional (type I) emergent Weyl fermions observed in TaAs still approximately respect Lorentz symmetry, recently, the so-called type II Weyl semimetal has been proposed, where the emergent Weyl quasiparticles break the Lorentz symmetry so strongly that they cannot be smoothly connected to Lorentz symmetric Weyl particles. Despite some evidence of nontrivial surface states, the direct observation of the type II bulk Weyl fermions remains elusive. We present the direct observation of the type II Weyl fermions in crystalline solid lanthanum aluminum germanide (LaAlGe) based on our photoemission data alone, without reliance on band structure calculations. Moreover, our systematic data agree with the theoretical calculations, providing further support on our experimental results. PMID:28630919
Direct optical detection of Weyl fermion chirality in a topological semimetal
NASA Astrophysics Data System (ADS)
Ma, Qiong; Xu, Su-Yang; Chan, Ching-Kit; Zhang, Cheng-Long; Chang, Guoqing; Lin, Yuxuan; Xie, Weiwei; Palacios, Tomás; Lin, Hsin; Jia, Shuang; Lee, Patrick A.; Jarillo-Herrero, Pablo; Gedik, Nuh
2017-09-01
A Weyl semimetal is a novel topological phase of matter, in which Weyl fermions arise as pseudo-magnetic monopoles in its momentum space. The chirality of the Weyl fermions, given by the sign of the monopole charge, is central to the Weyl physics, since it directly serves as the sign of the topological number and gives rise to exotic properties such as Fermi arcs and the chiral anomaly. Here, we directly detect the chirality of the Weyl fermions by measuring the photocurrent in response to circularly polarized mid-infrared light. The resulting photocurrent is determined by both the chirality of Weyl fermions and that of the photons. Our results pave the way for realizing a wide range of theoretical proposals for studying and controlling the Weyl fermions and their associated quantum anomalies by optical and electrical means. More broadly, the two chiralities, analogous to the two valleys in two-dimensional materials, lead to a new degree of freedom in a three-dimensional crystal with potential novel pathways to store and carry information.
New vector-like fermions and flavor physics
Ishiwata, Koji; Ligeti, Zoltan; Wise, Mark B.
2015-10-06
We study renormalizable extensions of the standard model that contain vector-like fermions in a (single) complex representation of the standard model gauge group. There are 11 models where the vector-like fermions Yukawa couple to the standard model fermions via the Higgs field. These models do not introduce additional fine-tunings. They can lead to, and are constrained by, a number of different flavor-changing processes involving leptons and quarks, as well as direct searches. An interesting feature of the models with strongly interacting vector-like fermions is that constraints from neutral meson mixings (apart from CP violation inmore » $$ {K}^0-{\\overline{K}}^0 $$ mixing) are not sensitive to higher scales than other flavor-changing neutral-current processes. We identify order 1/(4πM) 2 (where M is the vector-like fermion mass) one-loop contributions to the coefficients of the four-quark operators for meson mixing, that are not suppressed by standard model quark masses and/or mixing angles.« less
Continuity or Change? Gender, Family, and Academic Work for Junior Faculty in Ontario Universities
ERIC Educational Resources Information Center
Acker, Sandra; Webber, Michelle; Smyth, Elizabeth
2016-01-01
Over the past 40 or so years, women's share of faculty positions in Canada and elsewhere has increased considerably, if not yet reaching parity. Yet working in the gendered university remains problematic. This article uses data from a qualitative research project in which 38 junior academics were interviewed about their responses to being on the…
Entanglement entropies and fermion signs of critical metals
NASA Astrophysics Data System (ADS)
Kaplis, N.; Krüger, F.; Zaanen, J.
2017-04-01
The fermion sign problem is often viewed as a sheer inconvenience that plagues numerical studies of strongly interacting electron systems. Only recently has it been suggested that fermion signs are fundamental for the universal behavior of critical metallic systems and crucially enhance their degree of quantum entanglement. In this work we explore potential connections between emergent scale invariance of fermion sign structures and scaling properties of bipartite entanglement entropies. Our analysis is based on a wave-function Ansatz that incorporates collective, long-range backflow correlations into fermionic Slater determinants. Such wave functions mimic the collapse of a Fermi liquid at a quantum critical point. Their nodal surfaces, a representation of the fermion sign structure in many-particle configurations space, show fractal behavior up to a length scale ξ that diverges at a critical backflow strength. We show that the Hausdorff dimension of the fractal nodal surface depends on ξ , the number of fermions and the exponent of the backflow. For the same wave functions we numerically calculate the second Rényi entanglement entropy S2. Our results show a crossover from volume scaling, S2˜ℓθ (θ =2 in d =2 dimensions), to the characteristic Fermi-liquid behavior S2˜ℓ lnℓ on scales larger than ξ . We find that volume scaling of the entanglement entropy is a robust feature of critical backflow fermions, independent of the backflow exponent and hence the fractal dimension of the scale invariant sign structure.
NASA Astrophysics Data System (ADS)
Zhang, Wen; Liu, Yi; Wang, Xiaoying; Zhang, Yun; Xie, Donghua
2018-03-01
The heavy fermion physics arises from the complex interplay of nearly localized 4f/5f electrons and itinerant band-like ones, yielding heavy quasiparticles with an effective mass about 100 times (or more) of the bare electrons. Recently, experimental and theoretical investigations point out a localized and delocalized dual nature in actinide compounds, where itinerant quasiparticles account for the unconventional superconductivity in the vicinity of a magnetic instability. Here we report the strong coupling between localized 5f moments and itinerant quasiparticles in the ferromagnetic superconductor UGe2. The coupling is nearly antiferromagnetic. As embedded in the ferromagnetic matrix of localized 5f moments below {T}{{C}}≈ 52 {{K}}, this coupling leads to short-range dynamic correlations of heavy quasiparticles, characterized by fluctuations of magnetic clusters. Those cluster-like spins of itinerant quasiparticles show a broad hump of magnetization at {T}X≈ 28 {{K}}, which is typical for the spin-glass freezing. Thus, our results present the direct observation of itinerant quasiparticles coexisting with localized 5f moments by conventional magnetic measurements, providing a new route into the coexistence between ferromagnetism and superconductivity in heavy fermion systems. Project supported by the National Natural Science Foundation of China (Grant No. 11404297), the Science Challenge Project (Grant No. TZ2016004), and the Science and Technology Foundation of China Academy of Engineering Physics (Grant Nos. 2013B0301050 and 2014A0301013).
Parity & Untreated Dental Caries in US Women
Russell, S.L.; Ickovics, J.R.; Yaffee, R.A.
2010-01-01
While parity (number of children) reportedly is related to tooth loss, the relationship between parity and dental caries has not been extensively investigated. We used path analysis to test a theoretical model that specified that parity influences dental caries levels through dental care, psycho- social factors, and dental health damaging behaviors in 2635 women selected from the NHANES III dataset. We found that while increased parity was not associated with a greater level of total caries (DFS), parity was related to untreated dental caries (DS). The mechanisms by which parity is related to caries, however, remain undefined. Further investigation is warranted to determine if disparities in dental caries among women are due to differences in parity and the likely changes that parallel these reproductive choices. PMID:20631092
Parity & untreated dental caries in US women.
Russell, S L; Ickovics, J R; Yaffee, R A
2010-10-01
While parity (number of children) reportedly is related to tooth loss, the relationship between parity and dental caries has not been extensively investigated. We used path analysis to test a theoretical model that specified that parity influences dental caries levels through dental care, psycho- social factors, and dental health damaging behaviors in 2635 women selected from the NHANES III dataset. We found that while increased parity was not associated with a greater level of total caries (DFS), parity was related to untreated dental caries (DS). The mechanisms by which parity is related to caries, however, remain undefined. Further investigation is warranted to determine if disparities in dental caries among women are due to differences in parity and the likely changes that parallel these reproductive choices.
Separation of the 1+ /1- parity doublet in 20Ne
NASA Astrophysics Data System (ADS)
Beller, J.; Stumpf, C.; Scheck, M.; Pietralla, N.; Deleanu, D.; Filipescu, D. M.; Glodariu, T.; Haxton, W.; Idini, A.; Kelley, J. H.; Kwan, E.; Martinez-Pinedo, G.; Raut, R.; Romig, C.; Roth, R.; Rusev, G.; Savran, D.; Tonchev, A. P.; Tornow, W.; Wagner, J.; Weller, H. R.; Zamfir, N.-V.; Zweidinger, M.
2015-02-01
The (J , T) = (1 , 1) parity doublet in 20Ne at 11.26 MeV is a good candidate to study parity violation in nuclei. However, its energy splitting is known with insufficient accuracy for quantitative estimates of parity violating effects. To improve on this unsatisfactory situation, nuclear resonance fluorescence experiments using linearly and circularly polarized γ-ray beams were used to determine the energy difference of the parity doublet ΔE = E (1-) - E (1+) = - 3.2(± 0.7) stat(-1.2+0.6)sys keV and the ratio of their integrated cross sections Is,0(+) /Is,0(-) = 29(± 3) stat(-7+14)sys. Shell-model calculations predict a parity-violating matrix element having a value in the range 0.46-0.83 eV for the parity doublet. The small energy difference of the parity doublet makes 20Ne an excellent candidate to study parity violation in nuclear excitations.
Opendf - An Implementation of the Dual Fermion Method for Strongly Correlated Systems
NASA Astrophysics Data System (ADS)
Antipov, Andrey E.; LeBlanc, James P. F.; Gull, Emanuel
The dual fermion method is a multiscale approach for solving lattice problems of interacting strongly correlated systems. In this paper, we present the opendfcode, an open-source implementation of the dual fermion method applicable to fermionic single- orbital lattice models in dimensions D = 1, 2, 3 and 4. The method is built on a dynamical mean field starting point, which neglects all local correlations, and perturbatively adds spatial correlations. Our code is distributed as an open-source package under the GNU public license version 2.
Fermions tunnelling from the charged dilatonic black holes
NASA Astrophysics Data System (ADS)
Chen, De-You; Jiang, Qing-Quan; Zu, Xiao-Tao
2008-10-01
Kerner and Mann's recent work shows that for an uncharged and non-rotating black hole its Hawking temperature can be correctly derived by fermions tunnelling from its horizons. In this paper, our main work is to improve the analysis to deal with charged fermion tunnelling from the general dilatonic black holes, specifically including the charged, spherically symmetric dilatonic black hole, the rotating Einstein Maxwell dilaton axion (EMDA) black hole and the rotating Kaluza Klein (KK) black hole. As a result, the correct Hawking temperatures are well recovered by charged fermions tunnelling from these black holes.
SDG Fermion-Pair Algebraic SO(12) and Sp(10) Models and Their Boson Realizations
NASA Astrophysics Data System (ADS)
Navratil, P.; Geyer, H. B.; Dobes, J.; Dobaczewski, J.
1995-11-01
It is shown how the boson mapping formalism may be applied as a useful many-body tool to solve a fermion problem. This is done in the context of generalized Ginocchio models for which we introduce S-, D-, and G-pairs of fermions and subsequently construct the sdg-boson realizations of the generalized Dyson type. The constructed SO(12) and Sp(10) fermion models are solved beyond the explicit symmetry limits. Phase transitions to rotational structures are obtained also in situations where there is no underlying SU(3) symmetry.
Quantization of set theory and generalization of the fermion algebra
NASA Astrophysics Data System (ADS)
Arik, M.; Tekin, S. C.
2002-05-01
The quantum states of a d-dimensional fermion algebra are in one to one correspondence with the subsets of a d-element universal set. In this paper we use this set theoretical motivation to construct a one-parameter deformation of the fermion algebra and extend it to a d-dimensional generalization which is invariant under the group U(d). This discrete fermionic oscillator system is extended to the continuous case. We also show that the q-deformation of these systems is related to supercovariant q-oscillators.
Baby Skyrme model and fermionic zero modes
NASA Astrophysics Data System (ADS)
Queiruga, J. M.
2016-09-01
In this work we investigate some features of the fermionic sector of the supersymmetric version of the baby Skyrme model. We find that, in the background of Bogomol'nyi-Prasad-Sommerfield compact baby Skyrmions, fermionic zero modes are confined to the defect core. Further, we show that, while three Supersymmetry (SUSY) generators are broken in the defect core, SUSY is completely restored outside. We study also the effect of a D-term deformation of the model. Such a deformation allows for the existence of fermionic zero modes and broken SUSY outside the compact defect.
Two-dimensional conductors with interactions and disorder from particle-vortex duality
NASA Astrophysics Data System (ADS)
Goldman, H.; Mulligan, M.; Raghu, S.; Torroba, G.; Zimet, M.
2017-12-01
We study Dirac fermions in two spatial dimensions (2D) coupled to strongly fluctuating U (1 ) gauge fields in the presence of quenched disorder. Such systems are dual to theories of free Dirac fermions, which are vortices of the original theory. In analogy to superconductivity, when these fermionic vortices localize, the original system becomes a perfect conductor, and when the vortices possess a finite conductivity, the original fermions do as well. We provide several realizations of this principle and thereby introduce examples of strongly interacting 2D metals that evade Anderson localization.
Instantons and Massless Fermions in Two Dimensions
DOE R&D Accomplishments Database
Callan, C. G. Jr.; Dashen, R.; Gross, D. J.
1977-05-01
The role of instantons in the breakdown of chiral U(N) symmetry is studied in a two dimensional model. Chiral U(1) is always destroyed by the axial vector anomaly. For N = 2 chiral SU(N) is also spontaneously broken yielding massive fermions and three (decoupled) Goldstone bosons. For N greater than or equal to 3 the fermions remain massless. Realistic four dimensional theories are believed to behave in a similar way but the critical N above which the fermions cease to be massive is not known in four dimensions.
Jia, Shaoyang; Pennington, M. R.
2016-12-12
In this paper, we derive the gauge covariance requirement imposed on the QED fermion-photon three-point function within the framework of a spectral representation for fermion propagators. When satisfied, such requirement ensures solutions to the fermion propagator Schwinger-Dyson equation (SDE) in any covariant gauge with arbitrary numbers of spacetime dimensions to be consistent with the Landau-Khalatnikov-Fradkin transformation (LKFT). The general result has been verified by the special cases of three and four dimensions. Additionally, we present the condition that ensures the vacuum polarization is independent of the gauge parameter. Finally, as an illustration, we show how the gauge technique dimensionally regularizedmore » in four dimensions does not satisfy the covariance requirement.« less
Diffusion in higher dimensional SYK model with complex fermions
NASA Astrophysics Data System (ADS)
Cai, Wenhe; Ge, Xian-Hui; Yang, Guo-Hong
2018-01-01
We construct a new higher dimensional SYK model with complex fermions on bipartite lattices. As an extension of the original zero-dimensional SYK model, we focus on the one-dimension case, and similar Hamiltonian can be obtained in higher dimensions. This model has a conserved U(1) fermion number Q and a conjugate chemical potential μ. We evaluate the thermal and charge diffusion constants via large q expansion at low temperature limit. The results show that the diffusivity depends on the ratio of free Majorana fermions to Majorana fermions with SYK interactions. The transport properties and the butterfly velocity are accordingly calculated at low temperature. The specific heat and the thermal conductivity are proportional to the temperature. The electrical resistivity also has a linear temperature dependence term.
Experimental Observation of Three-Component New Fermions in Topological Semimetal MoP
NASA Astrophysics Data System (ADS)
Lv, B. Q.; Feng, Z.-L.; Xu, Q.-N.; Ma, J.-Z.; Kong, L.-Y.; Richard, Pierre; Huang, Y.-B.; Strocov, V. N.; Fang, C.; Weng, H.-M.; Shi, Y.-G.; Qian, Tian; Ding, Hong; Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen PSI, Switzerland Team; Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics Team; University of Chinese Academy of Sciences, Beijing 100190, China Team; Collaborative Innovation Center of Quantum Matter, Beijing, China Collaboration; Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China Team
Condensed matter systems can host quasiparticle excitations that are analogues to elementary particles such as Majorana, Weyl, and Dirac fermions. Recent advances in band theory have expanded the classification of fermions in crystals, and revealed crystal symmetry-protected electron excitations that have no high-energy counterparts. Here, using angle-resolved photoemission spectroscopy, we demonstrate the existence of a triply degenerate point in the electronic structure of MoP crystal, where the quasiparticle excitations are beyond the Majorana-Weyl-Dirac classification. Furthermore, we observe pairs of Weyl points in the bulk electronic structure coexisting with the new fermions, thus introducing a platform for studying the interplay between different types of fermions. We thank Binbin Fu, Nan Xu, and Xin Gao for the assistance in the ARPES experiments.
Hamiltonian Cycle Enumeration via Fermion-Zeon Convolution
NASA Astrophysics Data System (ADS)
Staples, G. Stacey
2017-12-01
Beginning with a simple graph having finite vertex set V, operators are induced on fermion and zeon algebras by the action of the graph's adjacency matrix and combinatorial Laplacian on the vector space spanned by the graph's vertices. When the graph is simple (undirected with no loops or multiple edges), the matrices are symmetric and the induced operators are self-adjoint. The goal of the current paper is to recover a number of known graph-theoretic results from quantum observables constructed as linear operators on fermion and zeon Fock spaces. By considering an "indeterminate" fermion/zeon Fock space, a fermion-zeon convolution operator is defined whose trace recovers the number of Hamiltonian cycles in the graph. This convolution operator is a quantum observable whose expectation reveals the number of Hamiltonian cycles in the graph.
NASA Astrophysics Data System (ADS)
Giuliano, Domenico; Nava, Andrea
2015-09-01
Making a combined use of bosonization and fermionization techniques, we build nonlocal transformations between dual fermion operators, describing junctions of strongly interacting spinful one-dimensional quantum wires. Our approach allows for trading strongly interacting (in the original coordinates) fermionic Hamiltonians for weakly interacting (in the dual coordinates) ones. It enables us to generalize to the strongly interacting regime the fermionic renormalization group approach to weakly interacting junctions. As a result, on one hand, we are able to pertinently complement the information about the phase diagram of the junction obtained within the bosonization approach; on the other hand, we map out the full crossover of the conductance tensors between any two fixed points in the phase diagram connected by a renormalization group trajectory.
Chiral Majorana fermion modes in a quantum anomalous Hall insulator-superconductor structure.
He, Qing Lin; Pan, Lei; Stern, Alexander L; Burks, Edward C; Che, Xiaoyu; Yin, Gen; Wang, Jing; Lian, Biao; Zhou, Quan; Choi, Eun Sang; Murata, Koichi; Kou, Xufeng; Chen, Zhijie; Nie, Tianxiao; Shao, Qiming; Fan, Yabin; Zhang, Shou-Cheng; Liu, Kai; Xia, Jing; Wang, Kang L
2017-07-21
Majorana fermion is a hypothetical particle that is its own antiparticle. We report transport measurements that suggest the existence of one-dimensional chiral Majorana fermion modes in the hybrid system of a quantum anomalous Hall insulator thin film coupled with a superconductor. As the external magnetic field is swept, half-integer quantized conductance plateaus are observed at the locations of magnetization reversals, giving a distinct signature of the Majorana fermion modes. This transport signature is reproducible over many magnetic field sweeps and appears at different temperatures. This finding may open up an avenue to control Majorana fermions for implementing robust topological quantum computing. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
Hartree-Fock treatment of Fermi polarons using the Lee-Low-Pine transformation
NASA Astrophysics Data System (ADS)
Kain, Ben; Ling, Hong Y.
2017-09-01
We consider the Fermi polaron problem at zero temperature, where a single impurity interacts with noninteracting host fermions. We approach the problem starting with a Fröhlich-like Hamiltonian where the impurity is described with canonical position and momentum operators. We apply the Lee-Low-Pine (LLP) transformation to change the fermionic Fröhlich Hamiltonian into the fermionic LLP Hamiltonian, which describes a many-body system containing host fermions only. We adapt the self-consistent Hartree-Fock (HF) approach, first proposed by Edwards, to the fermionic LLP Hamiltonian in which a pair of host fermions with momenta k and k' interact with a potential proportional to k .k' . We apply the HF theory, which has the advantage of not restricting the number of particle-hole pairs, to repulsive Fermi polarons in one dimension. When the impurity and host fermion masses are equal our variational ansatz, where HF orbitals are expanded in terms of free-particle states, produces results in excellent agreement with McGuire's exact analytical results based on the Bethe ansatz. This work raises the prospect of using the HF ansatz and its time-dependent generalization as building blocks for developing all-coupling theories for both equilibrium and nonequilibrium Fermi polarons in higher dimensions.
Type-III and IV interacting Weyl points
NASA Astrophysics Data System (ADS)
Nissinen, J.; Volovik, G. E.
2017-04-01
3+1-dimensional Weyl fermions in interacting systems are described by effective quasi-relativistic Green's functions parametrized by a 16-element matrix e α μ in an expansion around the Weyl point. The matrix e α μ can be naturally identified as an effective tetrad field for the fermions. The correspondence between the tetrad field and an effective quasi-relativistic metric gμν governing the Weyl fermions allows for the possibility to simulate different classes of metric fields emerging in general relativity in interacting Weyl semimetals. According to this correspondence, there can be four types of Weyl fermions, depending on the signs of the components g 00 and g 00 of the effective metric. In addition to the conventional type-I fermions with a tilted Weyl cone and type-II fermions with an overtilted Weyl cone for g 00 > 0 and, respectively, g 00 > 0 or g 00 < 0, we find additional "type-III" and "type-IV" Weyl fermions with instabilities (complex frequencies) for g 00 < 0 and g 00 > 0 or g 00 < 0, respectively. While the type-I and type-II Weyl points allow us to simulate the black hole event horizon at an interface where g 00 changes sign, the type-III Weyl point leads to effective spacetimes with closed timelike curves.
Simple Z2 lattice gauge theories at finite fermion density
NASA Astrophysics Data System (ADS)
Prosko, Christian; Lee, Shu-Ping; Maciejko, Joseph
2017-11-01
Lattice gauge theories are a powerful language to theoretically describe a variety of strongly correlated systems, including frustrated magnets, high-Tc superconductors, and topological phases. However, in many cases gauge fields couple to gapless matter degrees of freedom, and such theories become notoriously difficult to analyze quantitatively. In this paper we study several examples of Z2 lattice gauge theories with gapless fermions at finite density, in one and two spatial dimensions, that are either exactly soluble or whose solution reduces to that of a known problem. We consider complex fermions (spinless and spinful) as well as Majorana fermions and study both theories where Gauss' law is strictly imposed and those where all background charge sectors are kept in the physical Hilbert space. We use a combination of duality mappings and the Z2 slave-spin representation to map our gauge theories to models of gauge-invariant fermions that are either free, or with on-site interactions of the Hubbard or Falicov-Kimball type that are amenable to further analysis. In 1D, the phase diagrams of these theories include free-fermion metals, insulators, and superconductors, Luttinger liquids, and correlated insulators. In 2D, we find a variety of gapped and gapless phases, the latter including uniform and spatially modulated flux phases featuring emergent Dirac fermions, some violating Luttinger's theorem.
Wen, Hefei; Cummings, Janet R.; Hockenberry, Jason M.; Gaydos, Laura M.; Druss, Benjamin G.
2014-01-01
Context The passage of the 2008 Mental Health Parity and Addiction Equity Act (MHPAEA) and the 2010 Affordable Care Act (ACA) incorporated parity for substance use disorder (SUD) into federal legislation. Yet prior research provides us with scant evidence as to whether federal parity legislation will hold the potential for improving access to SUD treatment. Objective This study examined the effect of state-level SUD parity laws on state-aggregate SUD treatment rates from 2000 to 2008, to shed light on the impact of the recent federal-level SUD parity legislation. Design A quasi-experimental study design using a two-way (state and year) fixed-effect method Setting and Participants All known specialty SUD treatment facilities in the United States Interventions State-level SUD parity laws between 2000 and 2008 Main Outcome Measures State-aggregate SUD treatment rates in: (1) all specialty SUD treatment facilities, and (2) specialty SUD treatment facilities accepting private insurance Results The implementation of any SUD parity law increased the treatment rate by 9 percent (p<0.01) in all specialty SUD treatment facilities and by 15 percent (p<0.05) in facilities accepting private insurance. Full parity and parity-if-offered (i.e., parity only if SUD coverage is offered) increased SUD treatment rate by 13 percent (p<0.05) and 8 percent (p<0.05) in all facilities, and by 21 percent (p<0.05) and 10 percent (p<0.05) in those accepting private insurance. Conclusions We found a positive effect of the implementation of state SUD parity legislation on access to specialty SUD treatment. Furthermore, the positive association was more pronounced in states with more comprehensive parity laws. Our findings suggest that federal parity legislation holds the potential to improve access to SUD treatment. PMID:24154931
Heavy fermion behavior explained by bosons
NASA Technical Reports Server (NTRS)
Kallio, A.; Poykko, S.; Apaja, V.
1995-01-01
Conventional heavy fermion (HF) theories require existence of massive fermions. We show that heavy fermion phenomena can also be simply explained by existence of bosons with moderate mass but temperature dependent concentration below the formation temperature T(sub B), which in turn is close to room temperature. The bosons B(++) are proposed to be in chemical equilibrium with a system of holes h(+): B(++) = h(+) + h(+). This equilibrium is governed by a boson breaking function f(T), which determines the decreasing boson density and the increasing fermion density with increasing temperature. Since HF-compounds are hybridized from minimum two elements, we assume in addition existence of another fermion component h(sub s)(+) with temperature independent density. This spectator component is thought to be the main agent in binding the bosons in analogy with electronic or muonic molecules. Using a linear boson breaking function we can explain temperature dependence of the giant linear specific heat coefficient gamma(T) coming essentially from bosons. The maxima in resistivity, Hall coefficient, and susceptibility are explained by boson localization effects due to the Wigner crystallization. The antiferromagnetic transitions in turn are explained by similar localization of the pairing fermion system when their density n(sub h)(T(sub FL)) becomes lower than n(sub WC), the critical density of Wigner crystallization. The model applies irrespective whether a compound is superconducting or not. The same model explains the occurrence of low temperature antiferromagnetism also in high-T(sub c) superconductors. The double transition in UPt3 is proposed to be due to the transition of the pairing fermion liquid from spin polarized to unpolarized state.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shonder, John A; Hughes, Patrick; Atkin, Erica
2006-11-01
A study was sponsored by FEMP in 2001 - 2002 to develop methods to compare life-cycle costs of federal energy conservation projects carried out through energy savings performance contracts (ESPCs) and projects that are directly funded by appropriations. The study described in this report follows up on the original work, taking advantage of new pricing data on equipment and on $500 million worth of Super ESPC projects awarded since the end of FY 2001. The methods developed to compare life-cycle costs of ESPCs and directly funded energy projects are based on the following tasks: (1) Verify the parity of equipmentmore » prices in ESPC vs. directly funded projects; (2) Develop a representative energy conservation project; (3) Determine representative cycle times for both ESPCs and appropriations-funded projects; (4) Model the representative energy project implemented through an ESPC and through appropriations funding; and (5) Calculate the life-cycle costs for each project.« less
Infrared problem in non-Abelian gauge theory
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yao, Y.
1976-03-22
I extend the Bloch--Nordsieck idea to show that in the lowest nontrivial order of radiative correction the fermion--fermion and gauge-meson--fermion scattering rates are finite, provided that they are averaged over the initial and summed over the final internal spin states. Questions of the physical gauge coupling and infrared slavery are discussed. (AIP)
Superalgebra and fermion-boson symmetry
Miyazawa, Hironari
2010-01-01
Fermions and bosons are quite different kinds of particles, but it is possible to unify them in a supermultiplet, by introducing a new mathematical scheme called superalgebra. In this article we discuss the development of the concept of symmetry, starting from the rotational symmetry and finally arriving at this fermion-boson (FB) symmetry. PMID:20228617
Relaxation of Fermionic Excitations in a Strongly Attractive Fermi Gas in an Optical Lattice
2011-09-27
decreases both with temperature and deviation of the fermion density from half filling. We show that quasiparticle and phase degrees of freedom are...the interaction strength to the bandwidth of the system. Thus, at strong coupling, the fermionic quasiparticles and the motion of the bosonic molecules
Role of four-fermion interaction and impurity in the states of two-dimensional semi-Dirac materials.
Wang, Jing
2018-03-28
We study the effects of four-fermion interaction and impurity on the low-energy states of 2D semi-Dirac materials by virtue of the unbiased renormalization group approach. The coupled flow equations that govern the energy-dependent evolutions of all correlated interaction parameters are derived after taking into account one-loop corrections from the interplay between four-fermion interaction and impurity. Whether and how four-fermion interaction and impurity influence the low-energy properties of 2D semi-Dirac materials are discreetly explored and addressed attentively. After carrying out the standard renormalization group analysis, we find that both trivial insulating and nontrivial semimetal states are qualitatively stable against all four kinds of four-fermion interactions. However, while switching on both four-fermion interaction and impurity, certain insulator-semimetal phase transitions and the distance of Dirac nodal points can be respectively induced and modified due to their strong interplay and intimate competition. Moreover, several non-Fermi liquid behaviors that deviate from the conventional Fermi liquids are exhibited at the lowest-energy limit.
Bose-Fermi degeneracies in large N adjoint QCD
Basar, Gokce; Cherman, Aleksey; McGady, David
2015-07-06
Here, we analyze the large N limit of adjoint QCD, an SU( N) gauge theory with N f flavors of massless adjoint Majorana fermions, compactified on S 3 × S 1. We focus on the weakly-coupled confining small- S 3 regime. If the fermions are given periodic boundary conditions on S 1, we show that there are large cancellations between bosonic and fermionic contributions to the twisted partition function. These cancellations follow a pattern previously seen in the context of misaligned supersymmetry, and lead to the absence of Hagedorn instabilities for any S 1 size L, even though the bosonicmore » and fermionic densities of states both have Hagedorn growth. Adjoint QCD stays in the confining phase for any L ~ N 0, explaining how it is able to enjoy large N volume independence for any L. The large N boson-fermion cancellations take place in a setting where adjoint QCD is manifestly non-supersymmetric at any finite N, and are consistent with the recent conjecture that adjoint QCD has emergent fermionic symmetries in the large N limit.« less
NASA Astrophysics Data System (ADS)
Mukherjee, Anamitra; Patel, Niravkumar D.; Bishop, Chris; Dagotto, Elbio
2015-06-01
Lattice spin-fermion models are important to study correlated systems where quantum dynamics allows for a separation between slow and fast degrees of freedom. The fast degrees of freedom are treated quantum mechanically while the slow variables, generically referred to as the "spins," are treated classically. At present, exact diagonalization coupled with classical Monte Carlo (ED + MC) is extensively used to solve numerically a general class of lattice spin-fermion problems. In this common setup, the classical variables (spins) are treated via the standard MC method while the fermion problem is solved by exact diagonalization. The "traveling cluster approximation" (TCA) is a real space variant of the ED + MC method that allows to solve spin-fermion problems on lattice sizes with up to 103 sites. In this publication, we present a novel reorganization of the TCA algorithm in a manner that can be efficiently parallelized. This allows us to solve generic spin-fermion models easily on 104 lattice sites and with some effort on 105 lattice sites, representing the record lattice sizes studied for this family of models.
Fermionic entanglement that survives a black hole
NASA Astrophysics Data System (ADS)
Martín-Martínez, Eduardo; León, Juan
2009-10-01
We introduce an arbitrary number of accessible modes when analyzing bipartite entanglement degradation due to Unruh effect between two partners Alice and Rob. Under the single mode approximation (SMA) a fermion field only had a few accessible levels due to Pauli exclusion principle conversely to bosonic fields which had an infinite number of excitable levels. This was argued to justify entanglement survival in the fermionic case in the SMA infinite acceleration limit. Here we relax SMA. Hence, an infinite number of modes are excited as the observer Rob accelerates, even for a fermion field. We will prove that, despite this analogy with the bosonic case, entanglement loss is limited. We will show that this comes from fermionic statistics through the characteristic structure it imposes on the infinite dimensional density matrix for Rob. Surprisingly, the surviving entanglement is independent of the specific maximally entangled state chosen, the kind of fermionic field analyzed, and the number of accessible modes considered. We shall discuss whether this surviving entanglement goes beyond the purely statistical correlations, giving insight concerning the black hole information paradox.
Role of four-fermion interaction and impurity in the states of two-dimensional semi-Dirac materials
NASA Astrophysics Data System (ADS)
Wang, Jing
2018-03-01
We study the effects of four-fermion interaction and impurity on the low-energy states of 2D semi-Dirac materials by virtue of the unbiased renormalization group approach. The coupled flow equations that govern the energy-dependent evolutions of all correlated interaction parameters are derived after taking into account one-loop corrections from the interplay between four-fermion interaction and impurity. Whether and how four-fermion interaction and impurity influence the low-energy properties of 2D semi-Dirac materials are discreetly explored and addressed attentively. After carrying out the standard renormalization group analysis, we find that both trivial insulating and nontrivial semimetal states are qualitatively stable against all four kinds of four-fermion interactions. However, while switching on both four-fermion interaction and impurity, certain insulator-semimetal phase transitions and the distance of Dirac nodal points can be respectively induced and modified due to their strong interplay and intimate competition. Moreover, several non-Fermi liquid behaviors that deviate from the conventional Fermi liquids are exhibited at the lowest-energy limit.
Van Dyke, John S.; Massee, Freek; Allan, Milan P.; Davis, J. C. Séamus; Petrovic, Cedomir; Morr, Dirk K.
2014-01-01
To identify the microscopic mechanism of heavy-fermion Cooper pairing is an unresolved challenge in quantum matter studies; it may also relate closely to finding the pairing mechanism of high-temperature superconductivity. Magnetically mediated Cooper pairing has long been the conjectured basis of heavy-fermion superconductivity but no direct verification of this hypothesis was achievable. Here, we use a novel approach based on precision measurements of the heavy-fermion band structure using quasiparticle interference imaging to reveal quantitatively the momentum space (k-space) structure of the f-electron magnetic interactions of CeCoIn5. Then, by solving the superconducting gap equations on the two heavy-fermion bands Ekα,β with these magnetic interactions as mediators of the Cooper pairing, we derive a series of quantitative predictions about the superconductive state. The agreement found between these diverse predictions and the measured characteristics of superconducting CeCoIn5 then provides direct evidence that the heavy-fermion Cooper pairing is indeed mediated by f-electron magnetism. PMID:25062692
Zitterbewegung in time-reversal Weyl semimetals
NASA Astrophysics Data System (ADS)
Huang, Tongyun; Ma, Tianxing; Wang, Li-Gang
2018-06-01
We perform a systematic study of the Zitterbewegung effect of fermions, which are described by a Gaussian wave with broken spatial-inversion symmetry in a three-dimensional low-energy Weyl semimetal. Our results show that the motion of fermions near the Weyl points is characterized by rectilinear motion and Zitterbewegung oscillation. The ZB oscillation is affected by the width of the Gaussian wave packet, the position of the Weyl node, and the chirality and anisotropy of the fermions. By introducing a one-dimensional cosine potential, the new generated massless fermions have lower Fermi velocities, which results in a robust relativistic oscillation. Modulating the height and periodicity of periodic potential demonstrates that the ZB effect of fermions in the different Brillouin zones exhibits quasi-periodic behavior. These results may provide an appropriate system for probing the Zitterbewegung effect experimentally.
Trial wave functions for a composite Fermi liquid on a torus
NASA Astrophysics Data System (ADS)
Fremling, M.; Moran, N.; Slingerland, J. K.; Simon, S. H.
2018-01-01
We study the two-dimensional electron gas in a magnetic field at filling fraction ν =1/2 . At this filling the system is in a gapless state which can be interpreted as a Fermi liquid of composite fermions. We construct trial wave functions for the system on a torus, based on this idea, and numerically compare these to exact wave functions for small systems found by exact diagonalization. We find that the trial wave functions give an excellent description of the ground state of the system, as well as its charged excitations, in all momentum sectors. We analyze the dispersion of the composite fermions and the Berry phase associated with dragging a single fermion around the Fermi surface and comment on the implications of our results for the current debate on whether composite fermions are Dirac fermions.
Wigner functions for fermions in strong magnetic fields
NASA Astrophysics Data System (ADS)
Sheng, Xin-li; Rischke, Dirk H.; Vasak, David; Wang, Qun
2018-02-01
We compute the covariant Wigner function for spin-(1/2) fermions in an arbitrarily strong magnetic field by exactly solving the Dirac equation at non-zero fermion-number and chiral-charge densities. The Landau energy levels as well as a set of orthonormal eigenfunctions are found as solutions of the Dirac equation. With these orthonormal eigenfunctions we construct the fermion field operators and the corresponding Wigner-function operator. The Wigner function is obtained by taking the ensemble average of the Wigner-function operator in global thermodynamical equilibrium, i.e., at constant temperature T and non-zero fermion-number and chiral-charge chemical potentials μ and μ_5, respectively. Extracting the vector and axial-vector components of the Wigner function, we reproduce the currents of the chiral magnetic and separation effect in an arbitrarily strong magnetic field.
Benchmark results in the 2D lattice Thirring model with a chemical potential
NASA Astrophysics Data System (ADS)
Ayyar, Venkitesh; Chandrasekharan, Shailesh; Rantaharju, Jarno
2018-03-01
We study the two-dimensional lattice Thirring model in the presence of a fermion chemical potential. Our model is asymptotically free and contains massive fermions that mimic a baryon and light bosons that mimic pions. Hence, it is a useful toy model for QCD, especially since it, too, suffers from a sign problem in the auxiliary field formulation in the presence of a fermion chemical potential. In this work, we formulate the model in both the world line and fermion-bag representations and show that the sign problem can be completely eliminated with open boundary conditions when the fermions are massless. Hence, we are able accurately compute a variety of interesting quantities in the model, and these results could provide benchmarks for other methods that are being developed to solve the sign problem in QCD.
Low Density Parity Check Codes Based on Finite Geometries: A Rediscovery and More
NASA Technical Reports Server (NTRS)
Kou, Yu; Lin, Shu; Fossorier, Marc
1999-01-01
Low density parity check (LDPC) codes with iterative decoding based on belief propagation achieve astonishing error performance close to Shannon limit. No algebraic or geometric method for constructing these codes has been reported and they are largely generated by computer search. As a result, encoding of long LDPC codes is in general very complex. This paper presents two classes of high rate LDPC codes whose constructions are based on finite Euclidean and projective geometries, respectively. These classes of codes a.re cyclic and have good constraint parameters and minimum distances. Cyclic structure adows the use of linear feedback shift registers for encoding. These finite geometry LDPC codes achieve very good error performance with either soft-decision iterative decoding based on belief propagation or Gallager's hard-decision bit flipping algorithm. These codes can be punctured or extended to obtain other good LDPC codes. A generalization of these codes is also presented.
NASA Astrophysics Data System (ADS)
Kessel, Pan; Mkrtchyan, Karapet
2018-05-01
This work completes the classification of the cubic vertices for arbitrary-spin massless bosons in three dimensions started in a previous companion paper by constructing parity-odd vertices. Similarly to the parity-even case, there is a unique parity-odd vertex for any given triple s1≥s2≥s3≥2 of massless bosons if the triangle inequalities are satisfied (s1
Renormalization of Coulomb interactions in a system of two-dimensional tilted Dirac fermions
NASA Astrophysics Data System (ADS)
Lee, Yu-Wen; Lee, Yu-Li
2018-01-01
We investigate the effects of long-ranged Coulomb interactions in a tilted Dirac semimetal in two dimensions by using the perturbative renormalization-group (RG) method. Depending on the magnitude of the tilting parameter, the undoped system can have either Fermi points (type I) or Fermi lines (type II). Previous studies usually performed the renormalization-group transformations by integrating out the modes with large momenta. This is problematic when the Fermi surface is open, like type-II Dirac fermions. In this work we study the effects of Coulomb interactions, following the spirit of Shankar [Rev. Mod. Phys. 66, 129 (1994), 10.1103/RevModPhys.66.129], by introducing a cutoff in the energy scale around the Fermi surface and integrating out the high-energy modes. For type-I Dirac fermions, our result is consistent with that of the previous work. On the other hand, we find that for type-II Dirac fermions, the magnitude of the tilting parameter increases monotonically with lowering energies. This implies the stability of type-II Dirac fermions in the presence of Coulomb interactions, in contrast with previous results. Furthermore, for type-II Dirac fermions, the velocities in different directions acquire different renormalization even if they have the same bare values. By taking into account the renormalization of the tilting parameter and the velocities due to the Coulomb interactions, we show that while the presence of a charged impurity leads only to charge redistribution around the impurity for type-I Dirac fermions, for type-II Dirac fermions, the impurity charge is completely screened, albeit with a very long screening length. The latter indicates that the temperature dependence of physical observables are essentially determined by the RG equations we derived. We illustrate this by calculating the temperature dependence of the compressibility and specific heat of the interacting tilted Dirac fermions.
Grassmann phase space methods for fermions. II. Field theory
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dalton, B.J., E-mail: bdalton@swin.edu.au; Jeffers, J.; Barnett, S.M.
In both quantum optics and cold atom physics, the behaviour of bosonic photons and atoms is often treated using phase space methods, where mode annihilation and creation operators are represented by c-number phase space variables, with the density operator equivalent to a distribution function of these variables. The anti-commutation rules for fermion annihilation, creation operators suggests the possibility of using anti-commuting Grassmann variables to represent these operators. However, in spite of the seminal work by Cahill and Glauber and a few applications, the use of Grassmann phase space methods in quantum-atom optics to treat fermionic systems is rather rare, thoughmore » fermion coherent states using Grassmann variables are widely used in particle physics. This paper presents a phase space theory for fermion systems based on distribution functionals, which replace the density operator and involve Grassmann fields representing anti-commuting fermion field annihilation, creation operators. It is an extension of a previous phase space theory paper for fermions (Paper I) based on separate modes, in which the density operator is replaced by a distribution function depending on Grassmann phase space variables which represent the mode annihilation and creation operators. This further development of the theory is important for the situation when large numbers of fermions are involved, resulting in too many modes to treat separately. Here Grassmann fields, distribution functionals, functional Fokker–Planck equations and Ito stochastic field equations are involved. Typical applications to a trapped Fermi gas of interacting spin 1/2 fermionic atoms and to multi-component Fermi gases with non-zero range interactions are presented, showing that the Ito stochastic field equations are local in these cases. For the spin 1/2 case we also show how simple solutions can be obtained both for the untrapped case and for an optical lattice trapping potential.« less
ERIC Educational Resources Information Center
San Diego City Schools, CA.
The Materials Acquisition Project (MAP) was founded in 1970 under E.S.E.A. Title VII to collect educational materials published in Spanish- and Portuguese-speaking countries for assistance and use in bilingual education programs in the U.S. MAP believes in parity in all aspects of bilingual-bicultural education and offers guidelines for such an…
Progress towards ultracold gases in arbitrary 2D potentials
NASA Astrophysics Data System (ADS)
Corcovilos, Theodore
2016-05-01
We describe our progress in building an apparatus for investigating degenerate quantum gases of potassium in arbitrary two-dimensional optical potentials. The optical potentials are created by holographic projection of an image created using a MEMS mirror array. Systems we would like to study with this experiment are quantum simulations of bosons and fermions at crystal heterojunctions and systems with well defined boundaries, including topological edge states. Funding provided by the Charles E Kaufman Foundation, a part of the Pittsburgh Foundation.
Single event upset protection circuit and method
Wallner, John; Gorder, Michael
2016-03-22
An SEU protection circuit comprises first and second storage means for receiving primary and redundant versions, respectively, of an n-bit wide data value that is to be corrected in case of an SEU occurrence; the correction circuit requires that the data value be a 1-hot encoded value. A parity engine performs a parity operation on the n bits of the primary data value. A multiplexer receives the primary and redundant data values and the parity engine output at respective inputs, and is arranged to pass the primary data value to an output when the parity engine output indicates `odd` parity, and to pass the redundant data value to the output when the parity engine output indicates `even` parity. The primary and redundant data values are suitably state variables, and the parity engine is preferably an n-bit wide XOR or XNOR gate.
Fermion localization on a split brane
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chumbes, A. E. R.; Vasquez, A. E. O.; Hott, M. B.
2011-05-15
In this work we analyze the localization of fermions on a brane embedded in five-dimensional, warped and nonwarped, space-time. In both cases we use the same nonlinear theoretical model with a nonpolynomial potential featuring a self-interacting scalar field whose minimum energy solution is a soliton (a kink) which can be continuously deformed into a two-kink. Thus a single brane splits into two branes. The behavior of spin 1/2 fermions wave functions on the split brane depends on the coupling of fermions to the scalar field and on the geometry of the space-time.
DOE Office of Scientific and Technical Information (OSTI.GOV)
He, Qing Lin; Pan, Lei; Stern, Alexander L.
Majorana fermion is a hypothetical particle that is its own antiparticle. We report transport measurements that suggest the existence of one-dimensional chiral Majorana fermion modes in the hybrid system of a quantum anomalous Hall insulator thin film coupled with a superconductor. As the external magnetic field is swept, half-integer quantized conductance plateaus are observed at the locations of magnetization reversals, giving a distinct signature of the Majorana fermion modes. This transport signature is reproducible over many magnetic field sweeps and appears at different temperatures. This finding may open up an avenue to control Majorana fermions for implementing robust topological quantummore » computing.« less
Two-dimensional conductors with interactions and disorder from particle-vortex duality
Goldman, H.; Mulligan, M.; Raghu, S.; ...
2017-12-27
Here, we study Dirac fermions in two spatial dimensions (2D) coupled to strongly fluctuating U(1) gauge fields in the presence of quenched disorder. Such systems are dual to theories of free Dirac fermions, which are vortices of the original theory. In analogy to superconductivity, when these fermionic vortices localize, the original system becomes a perfect conductor, and when the vortices possess a finite conductivity, the original fermions do as well. We provide several realizations of this principle and thereby introduce examples of strongly interacting 2D metals that evade Anderson localization.
A search for excited fermions in electron-proton collisions at HERA
NASA Astrophysics Data System (ADS)
Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Repond, J.; Schlereth, J.; Stanek, R.; Talaga, R. L.; Thron, J.; Arzarello, F.; Ayad, R.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Bruni, P.; Romeo, G. Cara; Castellini, G.; Chiarini, M.; Cifarelli, L.; Cindolo, F.; Ciralli, F.; Contin, A.; D'Auria, S.; Frasconi, F.; Gialas, I.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Nemoz, C.; Palmonari, F.; Polini, A.; Sartorelli, G.; Timellini, R.; Garcia, Y. Zamora; Zichichi, A.; Bargende, A.; Crittenden, J.; Desch, K.; Diekmann, B.; Doeker, T.; Eckart, M.; Feld, L.; Frey, A.; Geerts, M.; Geitz, G.; Grothe, M.; Hartmann, H.; Haun, D.; Heinloth, K.; Hilger, E.; Jakob, H.-P.; Katz, U. F.; Mari, S. M.; Mass, A.; Mengel, S.; Mollen, J.; Paul, E.; Rembser, Ch.; Schattevoy, R.; Schneider, J.-L.; Schramm, D.; Stamm, J.; Wedemeyer, R.; Campbell-Robson, S.; Cassidy, A.; Dyce, N.; Foster, B.; George, S.; Gilmore, R.; Heath, G. P.; Heath, H. F.; Llewellyn, T. J.; Morgado, C. J. S.; Norman, D. J. P.; O'Mara, J. A.; Tapper, R. J.; Wilson, S. S.; Yoshida, R.; Rau, R. R.; Arneodo, M.; Iannotti, L.; Schioppa, M.; Susinno, G.; Bernstein, A.; Caldwell, A.; Parsons, J. A.; Ritz, S.; Sciulli, F.; Straub, P. B.; Wai, L.; Yang, S.; Borzemski, P.; Chwastowski, J.; Eskreys, A.; Piotrzkowski, K.; Zachara, M.; Zawiejski, L.; Adamczyk, L.; Bednarek, B.; Eskreys, K.; Jeleń, K.; Kisielewska, D.; Kowalski, T.; Rulikowska-Zarebska, E.; Suszycki, L.; Zajac, J.; Kedzierski, T.; Kotański, A.; Przybycień, M.; Bauerdick, L. A. T.; Behrens, U.; Bienlein, J. K.; Böttcher, S.; Coldewey, C.; Drews, G.; Flasiński, M.; Gilkinson, D. J.; Göttlicher, P.; Gutjahr, B.; Haas, T.; Hain, W.; Hasell, D.; Heßling, H.; Hultschig, H.; Iga, Y.; Joos, P.; Kasemann, M.; Klanner, R.; Koch, W.; Köpke, L.; Kötz, U.; Kowalski, H.; Kroger, W.; Krüger, J.; Labs, J.; Ladage, A.; Löhr, B.; Löwe, M.; Lüke, D.; Mańczak, O.; Ng, J. S. T.; Nickel, S.; Notz, D.; Ohrenberg, K.; Roco, M.; Rohde, M.; Roldán, J.; Schneekloth, U.; Schulz, W.; Selonke, F.; Stiliaris, E.; Voß, T.; Westphal, D.; Wolf, G.; Youngman, C.; Grabosch, H. J.; Leich, A.; Meyer, A.; Rethfeldt, C.; Schlenstedt, S.; Barbagli, G.; Pelfer, P.; Anzivino, G.; Maccarrone, G.; de Pasquale, S.; Qian, S.; Votano, L.; Bamberger, A.; Freidhof, A.; Poser, T.; Söldner-Rembold, S.; Schroeder, J.; Theisen, G.; Trefzger, T.; Brook, N. H.; Bussey, P. J.; Doyle, A. T.; Fleck, I.; Jamieson, V. A.; Saxon, D. H.; Utley, M. L.; Wilson, A. S.; Dannemann, A.; Holm, U.; Horstmann, D.; Kammerlocher, H.; Krebs, B.; Neumann, T.; Sinkus, R.; Wick, K.; Badura, E.; Burow, B. D.; Fürtjes, A.; Hagge, L.; Lohrmann, E.; Mainusch, J.; Milewski, J.; Nakahata, M.; Pavel, N.; Poelz, G.; Schott, W.; Terron, J.; Zetsche, F.; Bacon, T. C.; Beuselinck, R.; Butterworth, I.; Gallo, E.; Harris, V. L.; Hung, B. H.; Long, K. R.; Miller, D. B.; Morawitz, P. P. O.; Prinias, A.; Sedgbeer, J. K.; Whitfield, A. F.; Mallik, U.; McCliment, E.; Wang, M. Z.; Wang, S. M.; Wu, J. T.; Zhang, Y.; Cloth, P.; Filges, D.; An, S. H.; Hong, S. M.; Nam, S. W.; Park, S. K.; Suh, M. H.; Yon, S. H.; Imlay, R.; Kartik, S.; Kim, H.-J.; McNeil, R. R.; Metcalf, W.; Nadendla, V. K.; Barreiro, F.; Cases, G.; Graciani, R.; Hernández, J. M.; Hervás, L.; Labarga, L.; Del Peso, J.; Puga, J.; de Trocóniz, J. F.; Ikraiam, F.; Mayer, J. K.; Smith, G. R.; Corriveau, F.; Hanna, D. S.; Hartmann, J.; Hung, L. W.; Lim, J. N.; Matthews, C. G.; Patel, P. M.; Sinclair, L. E.; Stairs, D. G.; St. Laurent, M.; Ullmann, R.; Zacek, G.; Bashkirov, V.; Dolgoshein, B. A.; Stifutkin, A.; Bashindzhagyan, G. L.; Ermolov, P. F.; Gladilin, L. K.; Golubkov, Y. A.; Kobrin, V. D.; Kuzmin, V. A.; Proskuryakov, A. S.; Savin, A. A.; Shcheglova, L. M.; Solomin, A. N.; Zotov, N. P.; Bentvelsen, S.; Botje, M.; Chlebana, F.; Dake, A.; Engelen, J.; de Jong, P.; de Kamps, M.; Kooijman, P.; Kruse, A.; O'Dell, V.; Tenner, A.; Tiecke, H.; Verkerke, W.; Vreeswijk, M.; Wiggers, L.; de Wolf, E.; van Woudenberg, R.; Acosta, D.; Bylsma, B.; Durkin, L. S.; Honscheid, K.; Li, C.; Ling, T. Y.; McLean, K. W.; Murray, W. N.; Park, I. H.; Romanowski, T. A.; Seidlein, R.; Bailey, D. S.; Blair, G. A.; Byrne, A.; Cashmore, R. J.; Cooper-Sarkar, A. M.; Daniels, D.; Devenish, R. C. E.; Harnew, N.; Lancaster, M.; Luffman, P. E.; Lindemann, L.; McFall, J.; Nath, C.; Quadt, A.; Uijterwaal, H.; Walczak, R.; Wilson, F. F.; Yip, T.; Abbiendi, G.; Bertolin, A.; Brugnera, R.; Carlin, R.; Dal Corso, F.; de Giorgi, M.; Dosselli, U.; Limentani, S.; Morandin, M.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Bulmahn, J.; Butterworth, J. M.; Feild, R. G.; Oh, B. Y.; Whitmore, J. J.; D'Agostini, G.; Iori, M.; Marini, G.; Mattioli, M.; Nigro, A.; Tassi, E.; Hart, J. C.; McCubbin, N. A.; Prytz, K.; Shah, T. P.; Short, T. L.; Barberis, E.; Cartiglia, N.; Dubbs, T.; Heusch, C.; van Hook, M.; Hubbard, B.; Lockman, W.; Rahn, J. T.; Sadrozinski, H. F.-W.; Seiden, A.; Biltzinger, J.; Seifert, R. J.; Walenta, A. H.; Zech, G.; Abramowicz, H.; Briskin, G.; Dagan, S.; Levy, A.; Hasegawa, T.; Hazumi, M.; Ishii, T.; Kuze, M.; Mine, S.; Nagasawa, Y.; Nagira, T.; Nakao, M.; Suzuki, I.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Chiba, M.; Hamatsu, R.; Hirose, T.; Homma, K.; Kitamura, S.; Nagayama, S.; Nakamitsu, Y.; Cirio, R.; Costa, M.; Ferrero, M. I.; Lamberti, L.; Maselli, S.; Peroni, C.; Sacchi, R.; Solano, A.; Staiano, A.; Dardo, M.; Bailey, D. C.; Bandyopadhyay, D.; Benard, F.; Brkic, M.; Crombie, M. B.; Gingrich, D. M.; Hartner, G. F.; Joo, K. K.; Levman, G. M.; Martin, J. F.; Orr, R. S.; Sampson, C. R.; Teuscher, R. J.; Catterall, C. D.; Jones, T. W.; Kaziewicz, P. B.; Lane, J. B.; Saunders, R. L.; Shulman, J.; Blankenship, K.; Kochocki, J.; Lu, B.; Mo, L. W.; Bogusz, W.; Charchula, K.; Ciborowski, J.; Gajewski, J.; Grzelak, G.; Kasprazak, M.; Krzyżanowski, M.; Muchorowski, K.; Nowak, R. J.; Pawlak, J. M.; Tymieniecka, T.; Wróblewski, A. K.; Zakrzewski, J. A.; Żarnecki, A. F.; Adamus, M.; Eisenberg, Y.; Glasman, C.; Karshon, U.; Revel, D.; Shapira, A.; Ali, I.; Behrens, B.; Dasu, S.; Fordham, C.; Foudas, C.; Goussiou, A.; Loveless, R. J.; Reeder, D. D.; Silverstein, S.; Smith, W. H.; Tsurugai, T.; Bhadra, S.; Frisken, W. R.; Furutani, K. M.
1995-12-01
A search for excited states of the standard model fermions was performed using the ZEUS detector at the HERA electron-proton collider, operating at a centre of mass energy of 296 GeV. In a sample corresponding to an integrated luminosity of 0.55 pb-1, no evidence was found for any resonant state decaying into final states composed of a fermion and a gauge boson. Limits on the coupling strength times branching ratio of excited fermions are presented for masses between 50 GeV and 250 GeV, extending previous search regions significantly.
The 't Hooft vertex for staggered fermions and flavor-singlet mesons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Donald, Gordon C.; Davies, Christine T.H.; Follana, Eduardo
2011-01-01
We derive the ’t Hooft vertex for staggered fermions and examine its symmetries for nonzero lattice spacing. We also derive a set of structural properties for the eigenvectors of the staggered Dirac operator, which should emerge in the continuum limit, if staggered fermions yield four species. This property also is needed for flavor-taste-singlet correlators to behave correctly. We then test numerically whether the needed structure arises: it does. This structure and symmetry of (unrooted) staggered fermions also imply that Creutz’s (latest) objections to the rooted determinant are without foundation.
Cosmological BCS mechanism and the big bang singularity
NASA Astrophysics Data System (ADS)
Alexander, Stephon; Biswas, Tirthabir
2009-07-01
We provide a novel mechanism that resolves the big bang singularity present in Friedman-Lemaitre-Robertson-Walker space-times without the need for ghost fields. Building on the fact that a four-fermion interaction arises in general relativity when fermions are covariantly coupled, we show that at early times the decrease in scale factor enhances the correlation between pairs of fermions. This enhancement leads to a BCS-like condensation of the fermions and opens a gap dynamically driving the Hubble parameter H to zero and results in a nonsingular bounce, at least in some special cases.
Iliesiu, Luca; Kos, Filip; Poland, David; ...
2016-03-17
We study the conformal bootstrap for a 4-point function of fermions in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.
Two-dimensional conductors with interactions and disorder from particle-vortex duality
DOE Office of Scientific and Technical Information (OSTI.GOV)
Goldman, H.; Mulligan, M.; Raghu, S.
Here, we study Dirac fermions in two spatial dimensions (2D) coupled to strongly fluctuating U(1) gauge fields in the presence of quenched disorder. Such systems are dual to theories of free Dirac fermions, which are vortices of the original theory. In analogy to superconductivity, when these fermionic vortices localize, the original system becomes a perfect conductor, and when the vortices possess a finite conductivity, the original fermions do as well. We provide several realizations of this principle and thereby introduce examples of strongly interacting 2D metals that evade Anderson localization.
Fluctuations of a q-deformed fermion gas
NASA Astrophysics Data System (ADS)
Zeng, Qijun; Ge, Jing; Luo, Yongsong
2018-05-01
The theory of q-deformed fermions is one of the theories of q-deformed oscillators. Within the framework of this theory and the traditional fluctuation theory, we investigate fluctuations of q-deformed fermion gas and obtain the expressions of fluctuations of the internal energy U, the particle number N and the correlation of fluctuations of the two physical quantities above. Further numerical calculation reveals that fluctuations of such a system have some interesting and particular features. We consider that this work may provide much insight into the theory of q fermions, and may also be helpful for the theory of q-deformed oscillators.
NASA Astrophysics Data System (ADS)
Das, Aritra; Bandyopadhyay, Aritra; Roy, Pradip K.; Mustafa, Munshi G.
2018-02-01
We have systematically constructed the general structure of the fermion self-energy and the effective quark propagator in the presence of a nontrivial background such as a hot magnetized medium. This is applicable to both QED and QCD. The hard thermal loop approximation has been used for the heat bath. We have also examined transformation properties of the effective fermion propagator under some of the discrete symmetries of the system. Using the effective fermion propagator we have analyzed the fermion dispersion spectra in a hot magnetized medium along with the spinor for each fermion mode obtained by solving the modified Dirac equation. The fermion spectra is found to reflect the discrete symmetries of the two-point functions. We note that for a chirally symmetric theory the degenerate left- and right-handed chiral modes in vacuum or in a heat bath get separated and become asymmetric in the presence of a magnetic field without disturbing the chiral invariance. The obtained general structure of the two-point functions is verified by computing the three-point function, which agrees with the existing results in one-loop order. Finally, we have computed explicitly the spectral representation of the two-point functions which would be very important to study the spectral properties of the hot magnetized medium corresponding to QED and QCD with background magnetic field.
NASA Astrophysics Data System (ADS)
Zwierlein, Martin
2017-04-01
Strongly interacting fermions govern physics at all length scales, from nuclear matter to modern electronic materials and neutron stars. The interplay of the Pauli principle with strong interactions can give rise to exotic properties that we do not understand even at a qualitative level. In recent years, ultracold Fermi gases of atoms have emerged as a new type of strongly interacting fermionic matter that can be created and studied in the laboratory with exquisite control. Feshbach resonances allow for unitarity limited interactions, leading to scale invariance, universal thermodynamics and a superfluid phase transition already at 17 Trapped in optical lattices, fermionic atoms realize the Fermi-Hubbard model, believed to capture the essence of cuprate high-temperature superconductors. Here, a microscope allows for single-atom, single-site resolved detection of density and spin correlations, revealing the Pauli hole as well as anti-ferromagnetic and doublon-hole correlations. Novel states of matter are predicted for fermions interacting via long-range dipolar interactions. As an intriguing candidate we created stable fermionic molecules of NaK at ultralow temperatures featuring large dipole moments and second-long spin coherence times. In some of the above examples the experiment outperformed the most advanced computer simulations of many-fermion systems, giving hope for a new level of understanding of strongly interacting fermions.
Wen, Hefei; Cummings, Janet R; Hockenberry, Jason M; Gaydos, Laura M; Druss, Benjamin G
2013-12-01
The passage of the 2008 Mental Health Parity and Addiction Equity Act and the 2010 Affordable Care Act incorporated parity for substance use disorder (SUD) treatment into federal legislation. However, prior research provides us with scant evidence as to whether federal parity legislation will hold the potential for improving access to SUD treatment. To examine the effect of state-level SUD parity laws on state-aggregate SUD treatment rates and to shed light on the impact of the recent federal SUD parity legislation. We conducted a quasi-experimental study using a 2-way (state and year) fixed-effect method. We included all known specialty SUD treatment facilities in the United States and examined treatment rates from October 1, 2000, through March 31, 2008. Our main source of data was the National Survey of Substance Abuse Treatment Services, which provides facility-level information on specialty SUD treatment. State-level SUD parity laws during the study period. State-aggregate SUD treatment rates in (1) all specialty SUD treatment facilities and (2) specialty SUD treatment facilities accepting private insurance. The implementation of any SUD parity law increased the treatment rate by 9% (P < .001) in all specialty SUD treatment facilities and by 15% (P = .02) in facilities accepting private insurance. Full parity and parity only if SUD coverage is offered increased the SUD treatment rate by 13% (P = .02) and 8% (P = .04), respectively, in all facilities and by 21% (P = .03) and 10% (P = .04), respectively, in facilities accepting private insurance. We found a positive effect of the implementation of state SUD parity legislation on access to specialty SUD treatment. Furthermore, the positive association is more pronounced in states with more comprehensive parity laws. Our findings suggest that federal parity legislation holds the potential to improve access to SUD treatment.
Akter, Shamima; Jesmin, Subrina; Rahman, Md Mizanur; Islam, Md Majedul; Khatun, Most Tanzila; Yamaguchi, Naoto; Akashi, Hidechika; Mizutani, Taro
2013-01-01
Parity increases the risk for coronary heart disease; however, its association with metabolic syndrome among women in low-income countries is still unknown. This study investigates the association between parity or gravidity and metabolic syndrome in rural Bangladeshi women. A cross-sectional study was conducted in 1,219 women aged 15-75 years from rural Bangladesh. Metabolic syndrome was defined according to the standard NCEP-ATP III criteria. Logistic regression was used to estimate the association between parity and gravidity and metabolic syndrome, with adjustment of potential confounding variables. Subjects with the highest gravidity (> = 4) had 1.66 times higher odds of having metabolic syndrome compared to those in the lowest gravidity (0-1) (P trend = 0.02). A similar association was found between parity and metabolic syndrome (P(trend) = 0.04), i.e., subjects in the highest parity (> = 4) had 1.65 times higher odds of having metabolic syndrome compared to those in the lowest parity (0-1). This positive association of parity and gravidity with metabolic syndrome was confined to pre-menopausal women (P(trend) <0.01). Among the components of metabolic syndrome only high blood pressure showed positive association with parity and gravidity (P(trend) = 0.01 and <0.001). Neither Parity nor gravidity was appreciably associated with other components of metabolic syndrome. Multi parity or gravidity may be a risk factor for metabolic syndrome.
Theory of the disordered ν =5/2 quantum thermal Hall state: Emergent symmetry and phase diagram
NASA Astrophysics Data System (ADS)
Lian, Biao; Wang, Juven
2018-04-01
Fractional quantum Hall (FQH) system at Landau level filling fraction ν =5 /2 has long been suggested to be non-Abelian, either Pfaffian (Pf) or antiPfaffian (APf) states by numerical studies, both with quantized Hall conductance σx y=5 e2/2 h . Thermal Hall conductances of the Pf and APf states are quantized at κx y=7 /2 and κx y=3 /2 , respectively, in a proper unit. However, a recent experiment shows the thermal Hall conductance of ν =5 /2 FQH state is κx y=5 /2 . It has been speculated that the system contains random Pf and APf domains driven by disorders, and the neutral chiral Majorana modes on the domain walls may undergo a percolation transition to a κx y=5 /2 phase. In this paper, we do perturbative and nonperturbative analyses on the domain walls between Pf and APf. We show the domain wall theory possesses an emergent SO(4) symmetry at energy scales below a threshold Λ1, which is lowered to an emergent U (1 )×U (1) symmetry at energy scales between Λ1 and a higher value Λ2, and is finally lowered to the composite fermion parity symmetry Z2F above Λ2. Based on the emergent symmetries, we propose a phase diagram of the disordered ν =5 /2 FQH system and show that a κx y=5 /2 phase arises at disorder energy scales Λ >Λ1 . Furthermore, we show the gapped double-semion sector of ND compact domain walls contributes nonlocal topological degeneracy 2ND-1, causing a low-temperature peak in the heat capacity. We implement a nonperturbative method to bootstrap generic topological 1 +1 D domain walls (two-surface defects) applicable to any 2 +1 D non-Abelian topological order. We also identify potentially relevant spin topological quantum field theories (TQFTs) for various ν =5 /2 FQH states in terms of fermionic version of U (1) ±8 Chern-Simons theory ×Z8 -class TQFTs.
DOE Office of Scientific and Technical Information (OSTI.GOV)
BLUM,T.; SONI,A.
The workshop was held to mark the 10th anniversary of the first numerical simulations of QCD using domain wall fermions initiated at BNL. It is very gratifying that in the intervening decade widespread use of domain wall and overlap fermions is being made. It therefore seemed appropriate at this stage for some ''communal introspection'' of the progress that has been made, hurdles that need to be overcome, and physics that can and should be done with chiral fermions. The meeting was very well attended, drawing about 60 registered participants primarily from Europe, Japan and the US. It was quite remarkablemore » that pioneers David Kaplan, Herbert Neuberger, Rajamani Narayanan, Yigal Shamir, Sinya Aoki, and Pavlos Vranas all attended the workshop. Comparisons between domain wall and overlap formulations, with their respective advantages and limitations, were discussed at length, and a broad physics program including pion and kaon physics, the epsilon regime, nucleon structure, and topology, among others, emerged. New machines and improved algorithms have played a key role in realizing realistic dynamical fermion lattice simulations (small quark mass, large volume, and so on), so much in fact that measurements are now as costly. Consequently, ways to make the measurements more efficient were also discussed. We were very pleased to see the keen and ever growing interest in chiral fermions in our community and the significant strides our colleagues have made in bringing chiral fermions to the fore of lattice QCD calculations. Their contributions made the workshop a success, and we thank them deeply for sharing their time and ideas. Finally, we must especially acknowledge Norman Christ and Bob Mawhinney for their early and continued collaboration without which the success of domain wall fermions would not have been possible.« less
Mixed dark matter in left-right symmetric models
DOE Office of Scientific and Technical Information (OSTI.GOV)
Berlin, Asher; Fox, Patrick J.; Hooper, Dan
Motivated by the recently reported diboson and dijet excesses in Run 1 data at ATLAS and CMS, we explore models of mixed dark matter in left-right symmetric theories. In this study, we calculate the relic abundance and the elastic scattering cross section with nuclei for a number of dark matter candidates that appear within the fermionic multiplets of left-right symmetric models. In contrast to the case of pure multiplets, WIMP-nucleon scattering proceeds at tree-level, and hence the projected reach of future direct detection experiments such as LUX-ZEPLIN and XENON1T will cover large regions of parameter space for TeV-scale thermal darkmore » matter. Decays of the heavy charged W' boson to particles in the dark sector can potentially shift the right-handed gauge coupling to larger values when fixed to the rate of the Run 1 excesses, moving towards the theoretically attractive scenario, g R = g L. Furthermore, this region of parameter space may be probed by future collider searches for new Higgs bosons or electroweak fermions.« less
Mixed dark matter in left-right symmetric models
DOE Office of Scientific and Technical Information (OSTI.GOV)
Berlin, Asher; Fox, Patrick J.; Hooper, Dan
Motivated by the recently reported diboson and dijet excesses in Run 1 data at ATLAS and CMS, we explore models of mixed dark matter in left-right symmetric theories. In this study, we calculate the relic abundance and the elastic scattering cross section with nuclei for a number of dark matter candidates that appear within the fermionic multiplets of left-right symmetric models. In contrast to the case of pure multiplets, WIMP-nucleon scattering proceeds at tree-level, and hence the projected reach of future direct detection experiments such as LUX-ZEPLIN and XENON1T will cover large regions of parameter space for TeV-scale thermal darkmore » matter. Decays of the heavy charged W{sup ′} boson to particles in the dark sector can potentially shift the right-handed gauge coupling to larger values when fixed to the rate of the Run 1 excesses, moving towards the theoretically attractive scenario, g{sub R}=g{sub L}. This region of parameter space may be probed by future collider searches for new Higgs bosons or electroweak fermions.« less
Mixed dark matter in left-right symmetric models
Berlin, Asher; Fox, Patrick J.; Hooper, Dan; ...
2016-06-08
Motivated by the recently reported diboson and dijet excesses in Run 1 data at ATLAS and CMS, we explore models of mixed dark matter in left-right symmetric theories. In this study, we calculate the relic abundance and the elastic scattering cross section with nuclei for a number of dark matter candidates that appear within the fermionic multiplets of left-right symmetric models. In contrast to the case of pure multiplets, WIMP-nucleon scattering proceeds at tree-level, and hence the projected reach of future direct detection experiments such as LUX-ZEPLIN and XENON1T will cover large regions of parameter space for TeV-scale thermal darkmore » matter. Decays of the heavy charged W' boson to particles in the dark sector can potentially shift the right-handed gauge coupling to larger values when fixed to the rate of the Run 1 excesses, moving towards the theoretically attractive scenario, g R = g L. Furthermore, this region of parameter space may be probed by future collider searches for new Higgs bosons or electroweak fermions.« less
Veselago focusing of anisotropic massless Dirac fermions
NASA Astrophysics Data System (ADS)
Zhang, Shu-Hui; Yang, Wen; Peeters, F. M.
2018-05-01
Massless Dirac fermions (MDFs) emerge as quasiparticles in various novel materials such as graphene and topological insulators, and they exhibit several intriguing properties, of which Veselago focusing is an outstanding example with a lot of possible applications. However, up to now Veselago focusing merely occurred in p-n junction devices based on the isotropic MDF, which lacks the tunability needed for realistic applications. Here, motivated by the emergence of novel Dirac materials, we investigate the propagation behaviors of anisotropic MDFs in such a p-n junction structure. By projecting the Hamiltonian of the anisotropic MDF to that of the isotropic MDF and deriving an exact analytical expression for the propagator, precise Veselago focusing is demonstrated without the need for mirror symmetry of the electron source and its focusing image. We show a tunable focusing position that can be used in a device to probe masked atom-scale defects. This study provides an innovative concept to realize Veselago focusing relevant for potential applications, and it paves the way for the design of novel electron optics devices by exploiting the anisotropic MDF.
Dark Energy and Dark Matter as w = -1 Virtual Particles and the World Hologram Model
NASA Astrophysics Data System (ADS)
Sarfatti, Jack
2011-04-01
The elementary physics battle-tested principles of Lorentz invariance, Einstein equivalence principle and the boson commutation and fermion anti-commutation rules of quantum field theory explain gravitationally repulsive dark energy as virtual bosons and gravitationally attractive dark matter as virtual fermion-antifermion pairs. The small dark energy density in our past light cone is the reciprocal entropy-area of our future light cone's 2D future event horizon in a Novikov consistent loop in time in our accelerating universe. Yakir Aharonov's "back-from-the-future" post-selected final boundary condition is set at our observer-dependent future horizon that also explains why the irreversible thermodynamic arrow of time of is aligned with the accelerating dark energy expansion of the bulk 3D space interior to our future 2D horizon surrounding it as the hologram screen. Seth Lloyd has argued that all 2D horizon surrounding surfaces are pixelated quantum computers projecting interior bulk 3D quanta of volume (Planck area)Sqrt(area of future horizon) as their hologram images in 1-1 correspondence.
Quasiparticle Representation of Coherent Nonlinear Optical Signals of Multiexcitons
NASA Astrophysics Data System (ADS)
Fingerhut, Benjamin; Bennet, Kochise; Roslyak, Oleksiy; Mukamel, Shaul
2013-03-01
Elementary excitations of many-Fermion systems can be described within the quasiparticle approach which is widely used in the calculation of transport and optical properties of metals, semiconductors, molecular aggregates and strongly correlated quantum materials. The excitations are then viewed as independent harmonic oscillators where the many-body interactions between the oscillators are mapped into anharmonicities. We present a Green's function approach based on coboson algebra for calculating nonlinear optical signals and apply it onwards the study of two and three exciton states. The method only requires the diagonalization of the single exciton manifold and avoids equations of motion of multi-exciton manifolds. Using coboson algebra many body effects are recast in terms of tetradic exciton-exciton interactions: Coulomb scattering and Pauli exchange. The physical space of Fermions is recovered by singular-value decomposition of the over-complete coboson basis set. The approach is used to calculate third and fifth order quantum coherence optical signals that directly probe correlations in two- and three exciton states and their projections on the two and single exciton manifold.
Permutation parity machines for neural cryptography.
Reyes, Oscar Mauricio; Zimmermann, Karl-Heinz
2010-06-01
Recently, synchronization was proved for permutation parity machines, multilayer feed-forward neural networks proposed as a binary variant of the tree parity machines. This ability was already used in the case of tree parity machines to introduce a key-exchange protocol. In this paper, a protocol based on permutation parity machines is proposed and its performance against common attacks (simple, geometric, majority and genetic) is studied.
Permutation parity machines for neural cryptography
DOE Office of Scientific and Technical Information (OSTI.GOV)
Reyes, Oscar Mauricio; Escuela de Ingenieria Electrica, Electronica y Telecomunicaciones, Universidad Industrial de Santander, Bucaramanga; Zimmermann, Karl-Heinz
2010-06-15
Recently, synchronization was proved for permutation parity machines, multilayer feed-forward neural networks proposed as a binary variant of the tree parity machines. This ability was already used in the case of tree parity machines to introduce a key-exchange protocol. In this paper, a protocol based on permutation parity machines is proposed and its performance against common attacks (simple, geometric, majority and genetic) is studied.
Chiral fermions in asymptotically safe quantum gravity
NASA Astrophysics Data System (ADS)
Meibohm, J.; Pawlowski, J. M.
2016-05-01
We study the consistency of dynamical fermionic matter with the asymptotic safety scenario of quantum gravity using the functional renormalisation group. Since this scenario suggests strongly coupled quantum gravity in the UV, one expects gravity-induced fermion self-interactions at energies of the Planck scale. These could lead to chiral symmetry breaking at very high energies and thus to large fermion masses in the IR. The present analysis which is based on the previous works (Christiansen et al., Phys Rev D 92:121501, 2015; Meibohm et al., Phys Rev D 93:084035, 2016), concludes that gravity-induced chiral symmetry breaking at the Planck scale is avoided for a general class of NJL-type models. We find strong evidence that this feature is independent of the number of fermion fields. This finding suggests that the phase diagram for these models is topologically stable under the influence of gravitational interactions.
Conceptual Foundations of Soliton Versus Particle Dualities Toward a Topological Model for Matter
NASA Astrophysics Data System (ADS)
Kouneiher, Joseph
2016-06-01
The idea that fermions could be solitons was actually confirmed in theoretical models in 1975 in the case when the space-time is two-dimensional and with the sine-Gordon model. More precisely S. Coleman showed that two different classical models end up describing the same fermions particle, when the quantum theory is constructed. But in one model the fermion is a quantum excitation of the field and in the other model the particle is a soliton. Hence both points of view can be reconciliated.The principal aim in this paper is to exhibit a solutions of topological type for the fermions in the wave zone, where the equations of motion are non-linear field equations, i.e. using a model generalizing sine- Gordon model to four dimensions, and describe the solutions for linear and circular polarized waves. In other words, the paper treat fermions as topological excitations of a bosonic field.
Two- and four-dimensional representations of the PT - and CPT -symmetric fermionic algebras
NASA Astrophysics Data System (ADS)
Beygi, Alireza; Klevansky, S. P.; Bender, Carl M.
2018-03-01
Fermionic systems differ from their bosonic counterparts, the main difference with regard to symmetry considerations being that T2=-1 for fermionic systems. In PT -symmetric quantum mechanics an operator has both PT and CPT adjoints. Fermionic operators η , which are quadratically nilpotent (η2=0 ), and algebras with PT and CPT adjoints can be constructed. These algebras obey different anticommutation relations: η ηPT+ηPTη =-1 , where ηPT is the PT adjoint of η , and η ηCPT+ηCPTη =1 , where ηCPT is the CPT adjoint of η . This paper presents matrix representations for the operator η and its PT and CPT adjoints in two and four dimensions. A PT -symmetric second-quantized Hamiltonian modeled on quantum electrodynamics that describes a system of interacting fermions and bosons is constructed within this framework and is solved exactly.
Chiral fermions in asymptotically safe quantum gravity.
Meibohm, J; Pawlowski, J M
2016-01-01
We study the consistency of dynamical fermionic matter with the asymptotic safety scenario of quantum gravity using the functional renormalisation group. Since this scenario suggests strongly coupled quantum gravity in the UV, one expects gravity-induced fermion self-interactions at energies of the Planck scale. These could lead to chiral symmetry breaking at very high energies and thus to large fermion masses in the IR. The present analysis which is based on the previous works (Christiansen et al., Phys Rev D 92:121501, 2015; Meibohm et al., Phys Rev D 93:084035, 2016), concludes that gravity-induced chiral symmetry breaking at the Planck scale is avoided for a general class of NJL-type models. We find strong evidence that this feature is independent of the number of fermion fields. This finding suggests that the phase diagram for these models is topologically stable under the influence of gravitational interactions.
Free-fermion descriptions of parafermion chains and string-net models
NASA Astrophysics Data System (ADS)
Meichanetzidis, Konstantinos; Turner, Christopher J.; Farjami, Ashk; Papić, Zlatko; Pachos, Jiannis K.
2018-03-01
Topological phases of matter remain a focus of interest due to their unique properties: fractionalization, ground-state degeneracy, and exotic excitations. While some of these properties can occur in systems of free fermions, their emergence is generally associated with interactions between particles. Here, we quantify the role of interactions in general classes of topological states of matter in one and two spatial dimensions, including parafermion chains and string-net models. Surprisingly, we find that certain topological states can be exactly described by free fermions, while others saturate the maximum possible distance from their optimal free-fermion description [C. J. Turner et al., Nat. Commun. 8, 14926 (2017), 10.1038/ncomms14926]. Our work opens the door to understanding the complexity of topological models by establishing new types of fermionization procedures to describe their low-energy physics, thus making them amenable to experimental realizations.
Phase diagram and re-entrant fermionic entanglement in a hybrid Ising-Hubbard ladder
NASA Astrophysics Data System (ADS)
Sousa, H. S.; Pereira, M. S. S.; de Oliveira, I. N.; Strečka, J.; Lyra, M. L.
2018-05-01
The degree of fermionic entanglement is examined in an exactly solvable Ising-Hubbard ladder, which involves interacting electrons on the ladder's rungs described by Hubbard dimers at half-filling on each rung, accounting for intrarung hopping and Coulomb terms. The coupling between neighboring Hubbard dimers is assumed to have an Ising-like nature. The ground-state phase diagram consists of four distinct regions corresponding to the saturated paramagnetic, the classical antiferromagnetic, the quantum antiferromagnetic, and the mixed classical-quantum phase. We have exactly computed the fermionic concurrence, which measures the degree of quantum entanglement between the pair of electrons on the ladder rungs. The effects of the hopping amplitude, the Coulomb term, temperature, and magnetic fields on the fermionic entanglement are explored in detail. It is shown that the fermionic concurrence displays a re-entrant behavior when quantum entanglement is being generated at moderate temperatures above the classical saturated paramagnetic ground state.
Sonneveldt, Emily; DeCormier Plosky, Willyanne; Stover, John
2013-01-01
A number of data sets show that high parity births are associated with higher child mortality than low parity births. The reasons for this relationship are not clear. In this paper we investigate whether high parity is associated with lower coverage of key health interventions that might lead to increased mortality. We used DHS data from 10 high fertility countries to examine the relationship between parity and coverage for 8 child health intervention and 9 maternal health interventions. We also used the LiST model to estimate the effect on maternal and child mortality of the lower coverage associated with high parity births. Our results show a significant relationship between coverage of maternal and child health services and birth order, even when controlling for poverty. The association between coverage and parity for maternal health interventions was more consistently significant across countries all countries, while for child health interventions there were fewer overall significant relationships and more variation both between and within countries. The differences in coverage between children of parity 3 and those of parity 6 are large enough to account for a 12% difference in the under-five mortality rate and a 22% difference in maternal mortality ratio in the countries studied. This study shows that coverage of key health interventions is lower for high parity children and the pattern is consistent across countries. This could be a partial explanation for the higher mortality rates associated with high parity. Actions to address this gap could help reduce the higher mortality experienced by high parity birth.
Power corrections to the universal heavy WIMP-nucleon cross section
NASA Astrophysics Data System (ADS)
Chen, Chien-Yi; Hill, Richard J.; Solon, Mikhail P.; Wijangco, Alexander M.
2018-06-01
WIMP-nucleon scattering is analyzed at order 1 / M in Heavy WIMP Effective Theory. The 1 / M power corrections, where M ≫mW is the WIMP mass, distinguish between different underlying UV models with the same universal limit and their impact on direct detection rates can be enhanced relative to naive expectations due to generic amplitude-level cancellations at leading order. The necessary one- and two-loop matching calculations onto the low-energy effective theory for WIMP interactions with Standard Model quarks and gluons are performed for the case of an electroweak SU(2) triplet WIMP, considering both the cases of elementary fermions and composite scalars. The low-velocity WIMP-nucleon scattering cross section is evaluated and compared with current experimental limits and projected future sensitivities. Our results provide the most robust prediction for electroweak triplet Majorana fermion dark matter direct detection rates; for this case, a cancellation between two sources of power corrections yields a small total 1 / M correction, and a total cross section close to the universal limit for M ≳ few × 100GeV. For the SU(2) composite scalar, the 1 / M corrections introduce dependence on underlying strong dynamics. Using a leading chiral logarithm evaluation, the total 1 / M correction has a larger magnitude and uncertainty than in the fermionic case, with a sign that further suppresses the total cross section. These examples provide definite targets for future direct detection experiments and motivate large scale detectors capable of probing to the neutrino floor in the TeV mass regime.
The Fermionic Projector, entanglement and the collapse of the wave function
NASA Astrophysics Data System (ADS)
Finster, Felix
2011-07-01
After a brief introduction to the fermionic projector approach, we review how entanglement and second quantized bosonic and fermionic fields can be described in this framework. The constructions are discussed with regard to decoherence phenomena and the measurement problem. We propose a mechanism leading to the collapse of the wave function in the quantum mechanical measurement process.
Drude Conductivity of Dirac Fermions in Graphene
2010-01-01
interband transitions, as required by the sum rule. Our surprising observation indicates that many-body effects and Dirac fermion-impurity interactions...reduction of free electron oscillator strength is corroborated by corresponding changes in graphene interband transitions, as required by the sum...dimensions. Researchers have demonstrated in graphene exotic Dirac fermion phenomena ranging from anomalous quantum Hall effects 1,2 to Klein tunneling 3 in
New excitations in the Thirring model
NASA Astrophysics Data System (ADS)
Cortés, J. L.; Gamboa, J.; Schmidt, I.; Zanelli, J.
1998-12-01
The quantization of the massless Thirring model in the light-cone using functional methods is considered. The need to compactify the coordinate x- in the light-cone spacetime implies that the quantum effective action for left-handed fermions contains excitations similar to abelian instantons produced by composite of left-handed fermions. Right-handed fermions don't have a similar effective action. Thus, quantum mechanically, chiral symmetry must be broken as a result of the topological excitations. The conserved charge associated to the topological states is quantized. Different cases with only fermionic excitations or bosonic excitations or both can occur depending on the boundary conditions and the value of the coupling.
Polar Kerr effect studies of time reversal symmetry breaking states in heavy fermion superconductors
Schemm, E. R.; Levenson-Falk, E. M.; Kapitulnik, A.
2016-11-30
The connection between chiral superconductivity and topological order has emerged as an active direction in research as more instances of both have been identified in condensed matter systems. Moreover, with the notable exception of 3He-B, all of the known or suspected chiral – that is to say time-reversal symmetry-breaking (TRSB) – superfluids arise in heavy fermion superconductors, although the vast majority of heavy fermion superconductors preserve time-reversal symmetry. We review recent experimental efforts to identify TRSB states in heavy fermion systems via measurement of polar Kerr effect, which is a direct consequence of TRSB.
NASA Astrophysics Data System (ADS)
Markov, Yu. A.; Shishmarev, A. A.
2010-11-01
Based on the most general principles of materiality, gauge, and re-parameterized invariance, the problem of constructing an action describing the dynamics of a classical color-charged particle moving in external non-Abelian gauge and fermion fields is considered. The case of a linear Lagrangian dependence on the external fermion fields is discussed. Within the framework of the description of the color degree of freedom of the particle with half-integer spin by the Grassmann color charges, a new concept of the Grassmann color source of the particle being a fermion analog of the conventional color current is introduced.
A beam splitter for Dirac-Weyl fermions through the Goos-Hänchen-like shift
NASA Astrophysics Data System (ADS)
Zheng, Ren-fei; Zhou, Lu; Zhang, Weiping
2017-12-01
We propose a method of realizing an effective beam splitter for Dirac-Weyl fermions through the Goos-Hänchen-like shift. It is implemented via the birefringence of a wave packet of pseudospin-3/2 Dirac-Weyl fermions impinging upon a potential barrier. It is shown that experimentally observable spatial separation between the transmitted fermions with helicity-1/2 and 3/2 can be generated by the Goos-Hänchen-like shift. The dependence of Goos-Hänchen-like shift and the corresponding transmission probability on the incident angle, the height and width of the potential barrier are carefully studied.
The Rational Hybrid Monte Carlo algorithm
NASA Astrophysics Data System (ADS)
Clark, Michael
2006-12-01
The past few years have seen considerable progress in algorithmic development for the generation of gauge fields including the effects of dynamical fermions. The Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is performed using a rational approximation in place the usual inverse quark matrix kernel is one of these developments. This algorithm has been found to be extremely beneficial in many areas of lattice QCD (chiral fermions, finite temperature, Wilson fermions etc.). We review the algorithm and some of these benefits, and we compare against other recent algorithm developements. We conclude with an update of the Berlin wall plot comparing costs of all popular fermion formulations.
Ladder physics in the spin fermion model
NASA Astrophysics Data System (ADS)
Tsvelik, A. M.
2017-05-01
A link is established between the spin fermion (SF) model of the cuprates and the approach based on the analogy between the physics of doped Mott insulators in two dimensions and the physics of fermionic ladders. This enables one to use nonperturbative results derived for fermionic ladders to move beyond the large-N approximation in the SF model. It is shown that the paramagnon exchange postulated in the SF model has exactly the right form to facilitate the emergence of the fully gapped d -Mott state in the region of the Brillouin zone at the hot spots of the Fermi surface. Hence, the SF model provides an adequate description of the pseudogap.
Stability of the two-dimensional Fermi polaron
NASA Astrophysics Data System (ADS)
Griesemer, Marcel; Linden, Ulrich
2018-02-01
A system composed of an ideal gas of N fermions interacting with an impurity particle in two space dimensions is considered. The interaction between impurity and fermions is given in terms of two-body point interactions whose strength is determined by the two-body binding energy, which is a free parameter of the model. If the mass of the impurity is 1.225 times larger than the mass of a fermion, it is shown that the energy is bounded below uniformly in the number N of fermions. This result improves previous, N-dependent lower bounds, and it complements a recent, similar bound for the Fermi polaron in three space dimensions.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kodama, Yuta; Kokubu, Kento; Sawado, Nobuyuki
We construct brane solutions in 6-dimensional Einstein-Skyrme systems. A class of baby-Skyrmion solutions realizes warped compactification of the extra dimensions and gravity localization on the brane for the negative bulk cosmological constant. Coupling of the fermions with brane Skyrmions leads to brane localized fermions. In terms of the level crossing picture, emergence of the massive localized modes are observed. The nonlinear nature of Skyrmions brings richer information for the fermions' level structure. It comprises doubly degenerate lowest plus single excited modes. Three generations of fundamental fermions are associated with this distinctive structure. The mass hierarchy of quarks or leptons appearedmore » in terms of slightly deformed baby Skyrmions with topological charge three.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chinotti, M.; Pal, A.; Ren, W. J.
Weyl fermions play a major role in quantum field theory but have been quite elusive as fundamental particles. These quasi-two-dimensional bismuth layers based materials were recently designed and provide an arena for studying the interplay between anisotropic Dirac fermions, magnetism, and structural changes, allowing the formation of Weyl fermions in condensed matter. We perform an optical investigation of YbMnBi 2 , a representative type-II Weyl semimetal, and contrast its excitation spectrum with the optical response of the more conventional semimetal EuMnBi 2 . This comparative study allows us to disentangle the optical fingerprints of type-II Weyl fermions, but also challengesmore » the present theoretical understanding of their electrodynamic response.« less
Fermion localization and resonances on a de Sitter thick brane
DOE Office of Scientific and Technical Information (OSTI.GOV)
Liu Yuxiao; Yang Jie; Zhao Zhenhua
2009-09-15
In C. A. S. Almeida, R. Casana, M. M. Ferreira, Jr., and A. R. Gomes, Phys. Rev. D 79, 125022 (2009), the simplest Yukawa coupling {eta}{psi}{phi}{chi}{psi} was considered for a two-scalar-generated Bloch brane model. Fermionic resonances for both chiralities were obtained, and their appearance is related to branes with internal structure. Inspired on this result, we investigate the localization and resonance spectrum of fermions on a one-scalar-generated de Sitter thick brane with a class of scalar-fermion couplings {eta}{psi}{phi}{sup k}{psi} with positive odd integer k. A set of massive fermionic resonances for both chiralities is obtained when provided large coupling constantmore » {eta}. We find that the masses and lifetimes of left and right chiral resonances are almost the same, which demonstrates that it is possible to compose massive Dirac fermions from the left and right chiral resonances. The resonance with lower mass has longer lifetime. For a same set of parameters, the number of resonances increases with k and the lifetime of the lower level resonance for larger k is much longer than the one for smaller k.« less
Superfluidity of identical fermions in an optical lattice: Atoms and polar molecules
NASA Astrophysics Data System (ADS)
Fedorov, A. K.; Yudson, V. I.; Shlyapnikov, G. V.
2018-02-01
In this work we discuss the emergence of p-wave superfluids of identical fermions in 2D lattices. The optical lattice potential manifests itself in an interplay between an increase in the density of states on the Fermi surface and the modification of the fermion-fermion interaction (scattering) amplitude. The density of states is enhanced due to an increase of the effective mass of atoms. In deep lattices, for short-range interacting atoms the scattering amplitude is strongly reduced compared to free space due to a small overlap of wavefunctions of fermions sitting in the neighboring lattice sites, which suppresses the p-wave superfluidity. However, we show that for a moderate lattice depth there is still a possibility to create atomic p-wave superfluids with sizable transition temperatures. The situation is drastically different for fermionic polar molecules. Being dressed with a microwave field, they acquire a dipole-dipole attractive tail in the interaction potential. Then, due to a long-range character of the dipole-dipole interaction, the effect of the suppression of the scattering amplitude in 2D lattices is absent. This leads to the emergence of a stable topological px + ipy superfluid of identical microwave-dressed polar molecules.
Mukherjee, Anamitra; Patel, Niravkumar D.; Bishop, Chris; ...
2015-06-08
Lattice spin-fermion models are quite important to study correlated systems where quantum dynamics allows for a separation between slow and fast degrees of freedom. The fast degrees of freedom are treated quantum mechanically while the slow variables, generically referred to as the “spins,” are treated classically. At present, exact diagonalization coupled with classical Monte Carlo (ED + MC) is extensively used to solve numerically a general class of lattice spin-fermion problems. In this common setup, the classical variables (spins) are treated via the standard MC method while the fermion problem is solved by exact diagonalization. The “traveling cluster approximation” (TCA)more » is a real space variant of the ED + MC method that allows to solve spin-fermion problems on lattice sizes with up to 10 3 sites. In this paper, we present a novel reorganization of the TCA algorithm in a manner that can be efficiently parallelized. Finally, this allows us to solve generic spin-fermion models easily on 10 4 lattice sites and with some effort on 10 5 lattice sites, representing the record lattice sizes studied for this family of models.« less
Nontrivial Berry phase in magnetic BaMnSb2 semimetal
Huang, Silu; Shelton, W. A.; Plummer, E. W.; Jin, Rongying
2017-01-01
The subject of topological materials has attracted immense attention in condensed-matter physics because they host new quantum states of matter containing Dirac, Majorana, or Weyl fermions. Although Majorana fermions can only exist on the surface of topological superconductors, Dirac and Weyl fermions can be realized in both 2D and 3D materials. The latter are semimetals with Dirac/Weyl cones either not tilted (type I) or tilted (type II). Although both Dirac and Weyl fermions have massless nature with the nontrivial Berry phase, the formation of Weyl fermions in 3D semimetals require either time-reversal or inversion symmetry breaking to lift degeneracy at Dirac points. Here we demonstrate experimentally that canted antiferromagnetic BaMnSb2 is a 3D Weyl semimetal with a 2D electronic structure. The Shubnikov–de Hass oscillations of the magnetoresistance give nearly zero effective mass with high mobility and the nontrivial Berry phase. The ordered magnetic arrangement (ferromagnetic ordering in the ab plane and antiferromagnetic ordering along the c axis below 286 K) breaks the time-reversal symmetry, thus offering us an ideal platform to study magnetic Weyl fermions in a centrosymmetric material. PMID:28539436
DOE Office of Scientific and Technical Information (OSTI.GOV)
Mukherjee, Anamitra; Patel, Niravkumar D.; Bishop, Chris
Lattice spin-fermion models are quite important to study correlated systems where quantum dynamics allows for a separation between slow and fast degrees of freedom. The fast degrees of freedom are treated quantum mechanically while the slow variables, generically referred to as the “spins,” are treated classically. At present, exact diagonalization coupled with classical Monte Carlo (ED + MC) is extensively used to solve numerically a general class of lattice spin-fermion problems. In this common setup, the classical variables (spins) are treated via the standard MC method while the fermion problem is solved by exact diagonalization. The “traveling cluster approximation” (TCA)more » is a real space variant of the ED + MC method that allows to solve spin-fermion problems on lattice sizes with up to 10 3 sites. In this paper, we present a novel reorganization of the TCA algorithm in a manner that can be efficiently parallelized. Finally, this allows us to solve generic spin-fermion models easily on 10 4 lattice sites and with some effort on 10 5 lattice sites, representing the record lattice sizes studied for this family of models.« less
Akter, Shamima; Jesmin, Subrina; Rahman, Md. Mizanur; Islam, Md. Majedul; Khatun, Most. Tanzila; Yamaguchi, Naoto; Akashi, Hidechika; Mizutani, Taro
2013-01-01
Background Parity increases the risk for coronary heart disease; however, its association with metabolic syndrome among women in low-income countries is still unknown. Objective This study investigates the association between parity or gravidity and metabolic syndrome in rural Bangladeshi women. Methods A cross-sectional study was conducted in 1,219 women aged 15–75 years from rural Bangladesh. Metabolic syndrome was defined according to the standard NCEP-ATP III criteria. Logistic regression was used to estimate the association between parity and gravidity and metabolic syndrome, with adjustment of potential confounding variables. Results Subjects with the highest gravidity (> = 4) had 1.66 times higher odds of having metabolic syndrome compared to those in the lowest gravidity (0-1) (P trend = 0.02). A similar association was found between parity and metabolic syndrome (P trend = 0.04), i.e., subjects in the highest parity (> = 4) had 1.65 times higher odds of having metabolic syndrome compared to those in the lowest parity (0-1). This positive association of parity and gravidity with metabolic syndrome was confined to pre-menopausal women (P trend <0.01). Among the components of metabolic syndrome only high blood pressure showed positive association with parity and gravidity (P trend = 0.01 and <0.001). Neither Parity nor gravidity was appreciably associated with other components of metabolic syndrome. Conclusions Multi parity or gravidity may be a risk factor for metabolic syndrome. PMID:23936302
Kim, Sonia A; Yount, Kathryn M; Ramakrishnan, Usha; Martorell, Reynaldo
2007-02-01
Recent studies support a positive relationship between parity and overweight among women of developing countries; however, it is unclear whether these effects vary by household wealth and national development. Our objective was to determine whether the association between parity and overweight [body mass index (BMI) > or =25 kg/m(2)] in women living in developing countries varies with levels of national human development and/or household wealth. We used data from 28 nationally representative, cross-sectional surveys conducted between 1996 and 2003 (n = 275 704 women, 15-49 years). The relationship between parity and overweight was modelled using logistic regression, controlling for several biological and sociodemographic factors and national development, as reflected by the United Nations' Human Development Index. We also modelled the interaction between parity and national development, and the three-way interaction between parity, household wealth and national development. Parity had a weak, positive association with overweight, which varied by household wealth and national development. Among the poorest women and women in the second tertile of household wealth, parity was positively related to overweight only in the most developed countries. Among the wealthiest women, parity was positively related to overweight regardless of the level of national development. As development increases, the burden of parity-related overweight shifts to include poor as well as wealthy women. In the least-developed countries, programmes to prevent parity-related overweight should target wealthy women, whereas such programmes should be provided to all women in more developed countries.
On the simulation of indistinguishable fermions in the many-body Wigner formalism
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sellier, J.M., E-mail: jeanmichel.sellier@gmail.com; Dimov, I.
2015-01-01
The simulation of quantum systems consisting of interacting, indistinguishable fermions is an incredible mathematical problem which poses formidable numerical challenges. Many sophisticated methods addressing this problem are available which are based on the many-body Schrödinger formalism. Recently a Monte Carlo technique for the resolution of the many-body Wigner equation has been introduced and successfully applied to the simulation of distinguishable, spinless particles. This numerical approach presents several advantages over other methods. Indeed, it is based on an intuitive formalism in which quantum systems are described in terms of a quasi-distribution function, and highly scalable due to its Monte Carlo nature.more » In this work, we extend the many-body Wigner Monte Carlo method to the simulation of indistinguishable fermions. To this end, we first show how fermions are incorporated into the Wigner formalism. Then we demonstrate that the Pauli exclusion principle is intrinsic to the formalism. As a matter of fact, a numerical simulation of two strongly interacting fermions (electrons) is performed which clearly shows the appearance of a Fermi (or exchange–correlation) hole in the phase-space, a clear signature of the presence of the Pauli principle. To conclude, we simulate 4, 8 and 16 non-interacting fermions, isolated in a closed box, and show that, as the number of fermions increases, we gradually recover the Fermi–Dirac statistics, a clear proof of the reliability of our proposed method for the treatment of indistinguishable particles.« less
NASA Astrophysics Data System (ADS)
Mendel Horwitz, Roberto Ruben
1982-03-01
In the framework of the Glashow-Weinberg-Salem model without elementary scalar particles, we show that masses for fermions and intermediate vector bosons can be generated dynamically. The mechanism is the formation of fermion-antifermion pseudoscalar bound states of zero total four momentum, which form a condensate in the physical vacuum. The force responsible for the binding is the short distance part of the net Coulomb force due to photon and Z exchange. Fermions and bosons acquire masses through their interaction with this condensate. The neutrinos remain massless because their righthanded components have no interactions. Also the charge -1/3 quarks remain massless because the repulsive force from the Z exchange dominates over the Coulomb force. To correct this, we propose two possible modifications to the theory. One is to cut off the Z exchange at very small distances, so that all fermions except the neutrinos acquire masses, which are then, purely electromagnetic in origin. The other is to introduce an additional gauge boson that couples to all quarks with a pure vector coupling. To make this vector boson unobservable at usual energies, at least two new fermions must couple to it. The vector boson squared masses receive additive contributions from all the fermion squared masses. The photon remains massless and the masses of the Z and W('(+OR -)) bosons are shown to be related through the Weinberg angle in the conventional way. Assuming only three families of fermions, we obtain estimates for the top quark mass.
Universal Behavior of Quantum Spin Liquid and Optical Conductivity in the Insulator Herbertsmithite
NASA Astrophysics Data System (ADS)
Shaginyan, V. R.; Msezane, A. Z.; Stephanovich, V. A.; Popov, K. G.; Japaridze, G. S.
2018-04-01
We analyze optical conductivity with the goal to demonstrate experimental manifestation of a new state of matter, the so-called fermion condensate. Fermion condensates are realized in quantum spin liquids, exhibiting typical behavior of heavy-fermion metals. Measurements of the low-frequency optical conductivity collected on the geometrically frustrated insulator herbertsmithite provide important experimental evidence of the nature of its quantum spin liquid composed of spinons. To analyze recent measurements of the herbertsmithite optical conductivity at different temperatures, we employ a model of strongly correlated quantum spin liquid located near the fermion condensation phase transition. Our theoretical analysis of the optical conductivity allows us to expose the physical mechanism of its temperature dependence. We also predict a dependence of the optical conductivity on a magnetic field. We consider an experimental manifestation (optical conductivity) of a new state of matter (so-called fermion condensate) realized in quantum spin liquids, for, in many ways, they exhibit typical behavior of heavy-fermion metals. Measurements of the low-frequency optical conductivity collected on the geometrically frustrated insulator herbertsmithite produce important experimental evidence of the nature of its quantum spin liquid composed of spinons. To analyze recent measurements of the herbertsmithite optical conductivity at different temperatures, we employ a model of a strongly correlated quantum spin liquid located near the fermion condensation phase transition. Our theoretical analysis of the optical conductivity allows us to reveal the physical mechanism of its temperature dependence. We also predict a dependence of the optical conductivity on a magnetic field.
NASA Astrophysics Data System (ADS)
Li, Wenyi; Ma, Guoli; Yu, Weitian; Zhang, Yujia; Liu, Mengli; Yang, Chunyu; Liu, Wenjun
2018-03-01
Not Available Project supported by the National Natural Science Foundation of China (Grant No. 11674036), the Beijing Youth Top-notch Talent Support Program, China (Grant No. 2017000026833ZK08), and the Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications) (Grant Nos. IPOC2016ZT04 and IPOC2017ZZ05).
NASA Astrophysics Data System (ADS)
Liu, Yun-Kai; Li, Biao
2017-01-01
Not Available Supported by the National Natural Science Foundation of China under Grant Nos 11271211, 11275072 and 11435005, the Ningbo Natural Science Foundation under Grant No 2015A610159, the Opening Project of Zhejiang Provincial Top Key Discipline of Physics Sciences in Ningbo University under Grant No xkzw11502, and the K. C. Wong Magna Fund in Ningbo University.
Lifetime measurement of high spin states in (75) Kr
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sheikh, Javid; Trivedi, T.; Maurya, K.
2010-01-01
The lifetimes of high spin states of {sup 75}Kr have been determined via {sup 50}Cr ({sup 28}Si, 2pn) {sup 75}Kr reaction in positive parity band using the Doppler-shift attenuation method. The transition quadrupole moments Q deduced from lifetime measurements have been compared with {sup 75}Br. Experimental results obtained from lifetime measurement are interpreted in the framework of projected shell model.
Competing forces in five-dimensional fermion condensation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yoon, Jongmin; Peskin, Michael E.
We study fermion condensation in the Randall-Sundrum background as a setting for composite Higgs models. We formalize the computation of the Coleman-Weinberg potential and present a simple, general formula. Using this tool, we study the competition of fermion multiplets with different boundary conditions, to find conditions for creating a little hierarchy with the Higgs field expectation value much smaller than the intrinsic Randall-Sundrum mass scale.
NASA Technical Reports Server (NTRS)
Wilczek, Frank
1987-01-01
A simple heuristic proof of the Nielsen-Ninomaya theorem is given. A method is proposed whereby the multiplication of fermion species on a lattice is reduced to the minimal doubling, in any dimension, with retention of appropriate chiral symmetries. Also, it is suggested that use of spatially thinned fermion fields is likely to be a useful and appropriate approximation in QCD - in any case, it is a self-checking one.
Competing forces in five-dimensional fermion condensation
Yoon, Jongmin; Peskin, Michael E.
2017-12-27
We study fermion condensation in the Randall-Sundrum background as a setting for composite Higgs models. We formalize the computation of the Coleman-Weinberg potential and present a simple, general formula. Using this tool, we study the competition of fermion multiplets with different boundary conditions, to find conditions for creating a little hierarchy with the Higgs field expectation value much smaller than the intrinsic Randall-Sundrum mass scale.
Competing forces in five-dimensional fermion condensation
NASA Astrophysics Data System (ADS)
Yoon, Jongmin; Peskin, Michael E.
2017-12-01
We study fermion condensation in the Randall-Sundrum background as a setting for composite Higgs models. We formalize the computation of the Coleman-Weinberg potential and present a simple, general formula. Using this tool, we study the competition of fermion multiplets with different boundary conditions, to find conditions for creating a little hierarchy with the Higgs field expectation value much smaller than the intrinsic Randall-Sundrum mass scale.
Aspects of Strongly Correlated Many-Body Fermi Systems
NASA Astrophysics Data System (ADS)
Porter, William J., III
A, by now, well-known signal-to-noise problem plagues Monte Carlo calculations of quantum-information-theoretic observables in systems of interacting fermions, particularly the Renyi entanglement entropies Sn, even in many cases where the infamous sign problem does not appear. Several methods have been put forward to circumvent this affliction including ensemble-switching techniques using auxiliary partition-function ratios. This dissertation presents an algorithm that modifies the recently proposed free-fermion decomposition in an essential way: we incorporate the entanglement-sensitive correlations directly into the probability measure in a natural way. Implementing this algorithm, we demonstrate that it is compatible with the hybrid Monte Carlo algorithm, the workhorse of the lattice quantum chromodynamics community and an essential tool for studying gauge theories that contain dynamical fermions. By studying a simple one-dimensional Hubbard model, we demonstrate that our method does not exhibit the same debilitating numerical difficulties that naive attempts to study entanglement often encounter. Following that, we illustrate some key probabilistic insights, using intuition derived from the previous method and its successes to construct a simpler, better behaved, and more elegant algorithm. Using this method, in combination with new identities which allow us to avoid seemingly necessary numerical difficulties, the inversion of the restricted one-body density matrices, we compute high order Renyi entropies and perform a thorough comparison to this new algorithm's predecessor using the Hubbard model mentioned before. Finally, we characterize non-perturbatively the Renyi entropies of degree n = 2,3,4, and 5 of three-dimensional, strongly coupled many-fermion systems in the scale-invariant regime of short interaction range and large scattering length, i.e. in the unitary limit using the algorithms detailed herein. We also detail an exact, few-body projective method which we use to characterize the entanglement properties of the two-body sector across a broad range of attractive couplings. In the many-body case, we determine universal scaling properties of this system, and for the two-body case, we compute the entanglement spectrum exactly, successfully characterizing a vast range of entanglement behavior across the BCS-BEC crossover.
Towards a heralded eigenstate-preserving measurement of multi-qubit parity in circuit QED
NASA Astrophysics Data System (ADS)
Huembeli, Patrick; Nigg, Simon E.
2017-07-01
Eigenstate-preserving multi-qubit parity measurements lie at the heart of stabilizer quantum error correction, which is a promising approach to mitigate the problem of decoherence in quantum computers. In this work we explore a high-fidelity, eigenstate-preserving parity readout for superconducting qubits dispersively coupled to a microwave resonator, where the parity bit is encoded in the amplitude of a coherent state of the resonator. Detecting photons emitted by the resonator via a current biased Josephson junction yields information about the parity bit. We analyze theoretically the measurement back action in the limit of a strongly coupled fast detector and show that in general such a parity measurement, while approximately quantum nondemolition is not eigenstate preserving. To remediate this shortcoming we propose a simple dynamical decoupling technique during photon detection, which greatly reduces decoherence within a given parity subspace. Furthermore, by applying a sequence of fast displacement operations interleaved with the dynamical decoupling pulses, the natural bias of this binary detector can be efficiently suppressed. Finally, we introduce the concept of a heralded parity measurement, where a detector click guarantees successful multi-qubit parity detection even for finite detection efficiency.
Non-Abelian S =1 chiral spin liquid on the kagome lattice
NASA Astrophysics Data System (ADS)
Liu, Zheng-Xin; Tu, Hong-Hao; Wu, Ying-Hai; He, Rong-Qiang; Liu, Xiong-Jun; Zhou, Yi; Ng, Tai-Kai
2018-05-01
We study S =1 spin liquid states on the kagome lattice constructed by Gutzwiller-projected px+i py superconductors. We show that the obtained spin liquids are either non-Abelian or Abelian topological phases, depending on the topology of the fermionic mean-field state. By calculating the modular matrices S and T , we confirm that projected topological superconductors are non-Abelian chiral spin liquid (NACSL). The chiral central charge and the spin Hall conductance we obtained agree very well with the S O (3) 1 (or, equivalently, S U (2) 2 ) field-theory predictions. We propose a local Hamiltonian which may stabilize the NACSL. From a variational study, we observe a topological phase transition from the NACSL to the Z2 Abelian spin liquid.
Multiparity evaluation of calving ease and stillbirth with separate genetic effects by parity.
Wiggans, G R; Cole, J B; Thornton, L L M
2008-08-01
Evaluations that analyze first and later parities as correlated traits were developed separately for calving ease (CE) from over 15 million calving records of Holsteins, Brown Swiss, and Holstein-Brown Swiss crossbreds and for stillbirth (SB) from 7.4 million of the Holstein CE records. Calving ease was measured on a scale of 1 (no difficulty) to 5 (difficult birth); SB status was designated as live or dead within 48 h. Scores for CE and SB were transformed separately for each trait by parity (first or later) and calf sex (male or female) and converted to a unit standard deviation scale. For variance component estimation, Holstein data were selected for the 2,968 bulls with the most records as sire or maternal grandsire (MGS). Six samples were selected by herd; samples ranged in size from 97,756 to 146,138 records. A multiparity sire-MGS model was used to calculate evaluations separately for CE and for SB with first and later parities as correlated traits. Fixed effects were year-season, calf sex, and sire and MGS birth years; random effects were herd-year interaction, sire, and MGS. For later parities, sex effects were separated by parity. The genetic correlation between first and later parities was 0.79 for sire and 0.81 for MGS for CE, and 0.83 for sire and 0.74 for MGS for SB. For national CE evaluations, which also include Brown Swiss, a fixed effect for breed was added to the model. Correlations between solutions on the underlying scale from the January 2008 USDA CE evaluation with those from the multiparity analysis for CE were 0.89 and 0.91 for first- and later-parity sire effects and 0.71 and 0.88 for first- and later-parity MGS effects; the larger value for later parity reflects that later parities comprised 64% of the data. Corresponding correlations for SB were 0.81 and 0.82 for first- and later-parity sire effects and 0.46 and 0.83 for first- and later-parity MGS effects, respectively. Correlations were higher when only bulls with a multiparity reliability of >65% were included. The multiparity analysis accounted for genetic differences in calving performance between first and later parities. Evaluations should become more stable as the portion of a bull's observations from different parities changes over his lifetime. Accuracy of the net merit index can be improved by adjusting weights to use evaluations for separate parities optimally.
Ugwuja, Emmanuel I; Nnabu, Richard C; Ezeonu, Paul O; Uro-Chukwu, Henry
2015-09-01
Adverse pregnancy outcome is an important public health problem that has been partly associated with increasing maternal parity. To determine the effect of parity on maternal body mass index (BMI), mineral element status and newborn anthropometrics. Data for 349 pregnant women previously studied for the impacts of maternal plasma mineral element status on pregnancy and its outcomes was analysed. Obstetric and demographic data and 5mls of blood samples were obtained from each subject. Blood lead, plasma copper, iron and zinc were determined using atomic absorption spectrophotometer. Maternal BMI increases with parity. Women with parity two had significantly higher plasma zinc but lower plasma copper with comparable levels of the elements in nulliparous and higher parity groups. Although plasma iron was comparable among the groups, blood lead was significantly higher in parity > three. Newborn birth length increases with parity with a positive correlation between parity and maternal BMI (r = 0.221; p = 0.001) and newborn birth length (r = 0.170; p = 0.002) while plasma copper was negatively correlated with newborn's head circumference (r = -0.115; p = 0.040). It is plausible that parity affects maternal BMI and newborn anthropometrics through alterations in maternal plasma mineral element levels. While further studies are desired to confirm the present findings, there is need for pregnant and would-be pregnant women to diversify their diet to optimize their mineral element status.
Iida, R; Piñeiro, C; Koketsu, Y
2015-05-01
Our objectives were 1) to compare reproductive performance across parity and lifetime performance in sow groups categorized by the number of pigs born alive (PBA) in parity 1 and 2) to examine the factors associated with more PBA in parity 1. We analyzed 476,816 parity records and 109,373 lifetime records of sows entered into 125 herds from 2008 to 2010. Sows were categorized into 4 groups based on the 10th, 50th, and 90th percentiles of PBA in parity 1 as follows: 7 pigs or fewer, 8 to 11 pigs, 12 to 14 pigs, and 15 pigs or more. Generalized linear models were applied to the data. For reproductive performance across parity, sows that had 15 or more PBA in parity 1 had 0.5 to 1.8 more PBA in any subsequent parity than the other 3 PBA groups ( P< 0.05). In addition, they had 2.8 to 5.4% higher farrowing rates in parities 1 through 3 than sows that had 7 or fewer PBA (P < 0.05). However, there were no differences between the sow PBA groups for weaning-to-first-mating interval in any parity (P ≥ 0.37). For lifetime performance, sows that had 15 or more PBA in parity 1 had 4.4 to 26.1 more lifetime PBA than sows that had 14 or fewer PBA (P < 0.05). Also, for sows that had 14 or fewer PBA in parity 1, those that were first mated at 229 d old (25th percentile) or earlier had 2.9 to 3.3 more lifetime PBA than those first mated at 278 d old (75th percentile) or later (P < 0.05). Factors associated with fewer PBA in parity 1 were summer mating and lower age of gilts at first mating (AFM; P < 0.05) but not reservice occurrences (P = 0.34). Additionally, there was a 2-way interaction between mated month groups and AFM for PBA in parity 1 (P < 0.05); PBA in parity 1 sows mated from July to December increased nonlinearly by 0.3 to 0.4 pigs when AFM increased from 200 to 310 d old (P < 0.05). However, the same rise in AFM had no significant effect on the PBA of sows mated between January and June (P ≥ 0.17). In conclusion, high PBA in parity 1 can be used to predict that a sow will have high reproductive performance and lifetime performance. Also, the data indicate that the upper limit of AFM for mating between July and December should be 278 d old.
Ladder physics in the spin fermion model
Tsvelik, A. M.
2017-05-01
A link is established between the spin fermion (SF) model of the cuprates and the approach based on the analogy between the physics of doped Mott insulators in two dimensions and the physics of fermionic ladders. This enables one to use nonperturbative results derived for fermionic ladders to move beyond the large-N approximation in the SF model. Here, it is shown that the paramagnon exchange postulated in the SF model has exactly the right form to facilitate the emergence of the fully gapped d-Mott state in the region of the Brillouin zone at the hot spots of the Fermi surface.more » Hence, the SF model provides an adequate description of the pseudogap.« less
Weak antilocalization of composite fermions in graphene
NASA Astrophysics Data System (ADS)
Laitinen, Antti; Kumar, Manohar; Hakonen, Pertti J.
2018-02-01
We demonstrate experimentally that composite fermions in monolayer graphene display weak antilocalization. Our experiments deal with fractional quantum Hall (FQH) states in high-mobility, suspended graphene Corbino disks in the vicinity of ν =1 /2 . We find a strong temperature dependence of conductivity σ away from half filling, which is consistent with the expected electron-electron interaction-induced gaps in the FQH state. At half filling, however, the temperature dependence of conductivity σ (T ) becomes quite weak, as anticipated for a Fermi sea of composite fermions, and we find a logarithmic dependence of σ on T . The sign of this quantum correction coincides with the weak antilocalization of graphene composite fermions, indigenous to chiral Dirac particles.
Numerical studies of a model fermion-boson system
NASA Astrophysics Data System (ADS)
Cheng, T.; Gospodarczyk, E. R.; Su, Q.; Grobe, R.
2010-02-01
We study the spectral and dynamical properties of a simplified model system of interacting fermions and bosons. The spatial discretization and an effective truncation of the Hilbert space permit us to compute the distribution of the bare fermions and bosons in the energy eigenstates of the coupled system. These states represent the physical particles and are used to examine the validity of the analytical predictions by perturbation theory and by the Greenberg-Schweber approximation that assumes all fermions are at rest. As an example of our numerical framework, we examine how a bare electron can trigger the creation of a cloud of virtual bosons around. We relate this cloud to the properties of the associated energy eigenstates.
Short interpregnancy interval and low birth weight: A role of parity.
Merklinger-Gruchala, Anna; Jasienska, Grazyna; Kapiszewska, Maria
2015-01-01
Short interpregnancy intervals (IPI) and high parity may be synergistically associated with the risk of unfavorable pregnancy outcomes. This study tests if the effect of short IPI on the odds ratio for low birth weight (LBW, <2,500 g) differs across parity status. The study was carried out on the birth registry sample of almost 40,000 singleton, live-born infants who were delivered between the years 1995 and 2009 to multiparous mothers whose residence at the time of infant's birth was the city of Krakow. Multiple logistic regression analyses were used for testing the effect of IPI on the odds ratio (OR) for LBW, after controlling for employment, educational and marital status, parity, sex of the child, maternal and gestational age. Stratified analyses (according to parity) and tests for interaction were performed. Very short IPI (0-5 months) was associated with an increased OR for LBW, but only among high parity mothers with three or more births (OR = 2.64; 95% CI 1.45-4.80). The test for interaction between very short IPI and parity on the OR for LBW was statistically significant after adjustment for multiple comparisons (P = 0.04). Among low parity mothers (two births) no statistically significant associations were found between IPI and LBW after standardization. Parity may modify the association between short birth spacing and LBW. Women with very short IPI and high parity may have a higher risk of having LBW infants than those with very short IPI but low parity. © 2015 Wiley Periodicals, Inc.
47 CFR 51.215 - Dialing parity: Cost recovery.
Code of Federal Regulations, 2010 CFR
2010-10-01
... (CONTINUED) INTERCONNECTION Obligations of All Local Exchange Carriers § 51.215 Dialing parity: Cost recovery. (a) A LEC may recover the incremental costs necessary for the implementation of toll dialing parity... 47 Telecommunication 3 2010-10-01 2010-10-01 false Dialing parity: Cost recovery. 51.215 Section...
Yang-Mills matrix mechanics and quantum phases
NASA Astrophysics Data System (ADS)
Pandey, Mahul; Vaidya, Sachindeo
The SU(2) Yang-Mills matrix model coupled to fundamental fermions is studied in the adiabatic limit, and quantum critical behavior is seen at special corners of the gauge field configuration space. The quantum scalar potential for the gauge field induced by the fermions diverges at the corners, and is intimately related to points of enhanced degeneracy of the fermionic Hamiltonian. This in turn leads to superselection sectors in the Hilbert space of the gauge field, the ground states in different sectors being orthogonal to each other. The SU(2) Yang-Mills matrix model coupled to two Weyl fermions has three quantum phases. When coupled to a massless Dirac fermion, the number of quantum phases is four. One of these phases is the color-spin locked phase. This paper is an extended version of the lectures given by the second author (SV) at the International Workshop on Quantum Physics: Foundations and Applications, Bangalore, in February 2016, and is based on [1].
Strings, boundary fermions and coincident D-branes
NASA Astrophysics Data System (ADS)
Wulff, Linus
2007-01-01
This thesis describes an attempt to write down covariant actions for coincident D-branes using so-called boundary fermions instead of matrices to describe the non-abelian fields. These fermions can be thought of as Chan-Paton degrees of freedom for the open string. It is shown that by gauge-fixing and by suitably quantizing these boundary fermions the non-abelian action that is known, the Myers action, can be reproduced. Furthermore it is shown that under natural assumptions, unlike the Myers action, the action formulated using boundary fermions also posseses kappa-symmetry when formulated on superspace. Another aspect of string theory discussed in this thesis is that of tensionless strings. These are of great interest for example because of their possible relation to higher spin gauge theories via the AdS/CFT-correspondence. The tensionless superstring in a plane wave background, a Penrose limit of the near-horizon geometry of a stack of D3-branes, is considered and compared to the tensile case.
Effect of boson on-site repulsion on the superfluidity in the boson-fermion-Hubbard model
NASA Astrophysics Data System (ADS)
Sajna, A. S.; Micnas, R.
2018-03-01
We analyze the finite-temperature phase diagram of the boson-fermion-Hubbard model with Feshbach converting interaction, using the coherent-state path-integral method. We show that depending on the position of the bosonic band, this type of interaction, even if weak, can drive the system into the resonant superfluid phase in the strong bosonic interaction limit. It turns out that this phase can exist for an arbitrary number of fermions (i.e., fermionic concentration between 0 and 2), but with the bosonic particle number very close to an integer value. We point out that the standard time-of-flight method in optical lattice experiments can be an adequate technique to confirm the existence of this resonant phase. Moreover, in the nonresonant regime, the enhancement of the critical temperature of the superfluid phase due to Feshbach interaction is also observed. We account for this interesting phenomena for a hole- or particlelike pairing mechanism depending on the system density and mutual location of the fermionic and bosonic bands.
NASA Astrophysics Data System (ADS)
Bergner, Georg; Piemonte, Stefano
2018-04-01
Non-Abelian gauge theories with fermions transforming in the adjoint representation of the gauge group (AdjQCD) are a fundamental ingredient of many models that describe the physics beyond the Standard Model. Two relevant examples are N =1 supersymmetric Yang-Mills (SYM) theory and minimal walking technicolor, which are gauge theories coupled to one adjoint Majorana and two adjoint Dirac fermions, respectively. While confinement is a property of N =1 SYM, minimal walking technicolor is expected to be infrared conformal. We study the propagators of ghost and gluon fields in the Landau gauge to compute the running coupling in the MiniMom scheme. We analyze several different ensembles of lattice Monte Carlo simulations for the SU(2) adjoint QCD with Nf=1 /2 ,1 ,3 /2 , and 2 Dirac fermions. We show how the running of the coupling changes as the number of interacting fermions is increased towards the conformal window.
Shen, Bing; Yu, Li; Liu, Kai; ...
2017-06-01
We have carried out high-resolution angle-resolved photoemission measurements on the Cebased heavy fermion compound CePt 2In 7 that exhibits stronger two-dimensional character than the prototypical heavy fermion system CeCoIn 5. Multiple Fermi surface sheets and a complex band structure are clearly resolved. We have also performed detailed band structure calculations on CePt 2In 7. The good agreement found between our measurements and the calculations suggests that the band renormalization effect is rather weak in CePt 2In 7. A comparison of the common features of the electronic structure of CePt 2In 7 and CeCoIn5 indicates that CeCoIn 5 shows a muchmore » stronger band renormalization effect than CePt 2In 7. These results provide new information for understanding the heavy fermion behaviors and unconventional superconductivity in Ce-based heavy fermion systems.« less
Hybrid Monte Carlo approach to the entanglement entropy of interacting fermions
NASA Astrophysics Data System (ADS)
Drut, Joaquín E.; Porter, William J.
2015-09-01
The Monte Carlo calculation of Rényi entanglement entropies Sn of interacting fermions suffers from a well-known signal-to-noise problem, even for a large number of situations in which the infamous sign problem is absent. A few methods have been proposed to overcome this issue, such as ensemble switching and the use of auxiliary partition-function ratios. Here, we present an approach that builds on the recently proposed free-fermion decomposition method; it incorporates entanglement in the probability measure in a natural way; it takes advantage of the hybrid Monte Carlo algorithm (an essential tool in lattice quantum chromodynamics and other gauge theories with dynamical fermions); and it does not suffer from noise problems. This method displays no sign problem for the same cases as other approaches and is therefore useful for a wide variety of systems. As a proof of principle, we calculate S2 for the one-dimensional, half-filled Hubbard model and compare with results from exact diagonalization and the free-fermion decomposition method.
Multipartite entanglement in fermionic systems via a geometric measure
NASA Astrophysics Data System (ADS)
Lari, Behzad; Durganandini, P.; Joag, Pramod S.
2010-12-01
We study multipartite entanglement in a system consisting of indistinguishable fermions. Specifically, we have proposed a geometric entanglement measure for N spin-(1)/(2) fermions distributed over 2L modes (single-particle states). The measure is defined on the 2L qubit space isomorphic to the Fock space for 2L single-particle states. This entanglement measure is defined for a given partition of 2L modes containing m⩾2 subsets. Thus this measure applies to m⩽2L partite fermionic systems where L is any finite number, giving the number of sites. The Hilbert spaces associated with these subsets may have different dimensions. Further, we have defined the local quantum operations with respect to a given partition of modes. This definition is generic and unifies different ways of dividing a fermionic system into subsystems. We have shown, using a representative case, that the geometric measure is invariant under local unitary operators corresponding to a given partition. We explicitly demonstrate the use of the measure to calculate multipartite entanglement in some correlated electron systems.
Production of black holes and their angular momentum distribution in models with split fermions
NASA Astrophysics Data System (ADS)
Dai, De-Chang; Starkman, Glenn D.; Stojkovic, Dejan
2006-05-01
In models with TeV-scale gravity it is expected that mini black holes will be produced in near-future accelerators. On the other hand, TeV-scale gravity is plagued with many problems like fast proton decay, unacceptably large n-n¯ oscillations, flavor changing neutral currents, large mixing between leptons, etc. Most of these problems can be solved if different fermions are localized at different points in the extra dimensions. We study the cross section for the production of black holes and their angular momentum distribution in these models with “split” fermions. We find that, for a fixed value of the fundamental mass scale, the total production cross section is reduced compared with models where all the fermions are localized at the same point in the extra dimensions. Fermion splitting also implies that the bulk component of the black hole angular momentum must be taken into account in studies of the black hole decay via Hawking radiation.
Entanglement and the fermion sign problem in auxiliary field quantum Monte Carlo simulations
NASA Astrophysics Data System (ADS)
Broecker, Peter; Trebst, Simon
2016-08-01
Quantum Monte Carlo simulations of fermions are hampered by the notorious sign problem whose most striking manifestation is an exponential growth of sampling errors with the number of particles. With the sign problem known to be an NP-hard problem and any generic solution thus highly elusive, the Monte Carlo sampling of interacting many-fermion systems is commonly thought to be restricted to a small class of model systems for which a sign-free basis has been identified. Here we demonstrate that entanglement measures, in particular the so-called Rényi entropies, can intrinsically exhibit a certain robustness against the sign problem in auxiliary-field quantum Monte Carlo approaches and possibly allow for the identification of global ground-state properties via their scaling behavior even in the presence of a strong sign problem. We corroborate these findings via numerical simulations of fermionic quantum phase transitions of spinless fermions on the honeycomb lattice at and below half filling.
The linear -- non-linear frontier for the Goldstone Higgs
Gavela, M. B.; Kanshin, K.; Machado, P. A. N.; ...
2016-12-01
The minimalmore » $SO(5)/SO(4)$ sigma model is used as a template for the ultraviolet completion of scenarios in which the Higgs particle is a low-energy remnant of some high-energy dynamics, enjoying a (pseudo) Nambu-Goldstone boson ancestry. Varying the $$\\sigma$$ mass allows to sweep from the perturbative regime to the customary non-linear implementations. The low-energy benchmark effective non-linear Lagrangian for bosons and fermions is obtained, determining as well the operator coefficients including linear corrections. At first order in the latter, three effective bosonic operators emerge which are independent of the explicit soft breaking assumed. The Higgs couplings to vector bosons and fermions turn out to be quite universal: the linear corrections are proportional to the explicit symmetry breaking parameters. Furthermore, we define an effective Yukawa operator which allows a simple parametrization and comparison of different heavy fermion ultraviolet completions. In addition, one particular fermionic completion is explored in detail, obtaining the corresponding leading low-energy fermionic operators.« less
Fermion-induced quantum criticality with two length scales in Dirac systems
NASA Astrophysics Data System (ADS)
Torres, Emilio; Classen, Laura; Herbut, Igor F.; Scherer, Michael M.
2018-03-01
The quantum phase transition to a Z3-ordered Kekulé valence bond solid in two-dimensional Dirac semimetals is governed by a fermion-induced quantum critical point, which renders the putatively discontinuous transition continuous. We study the resulting universal critical behavior in terms of a functional RG approach, which gives access to the scaling behavior on the symmetry-broken side of the phase transition, for general dimensions and number of Dirac fermions. In particular, we investigate the emergence of the fermion-induced quantum critical point for spacetime dimensions 2
Spectral properties of four-time fermionic Green's functions
Shvaika, A. M.
2016-09-01
The spectral relations for the four-time fermionic Green's functions are derived in the most general case. The terms which correspond to the zero-frequency anomalies, known before only for the bosonic Green's functions, are separated and their connection with the second cumulants of the Boltzmann distribution function is elucidated. Furthermore, the high-frequency expansions of the four-time fermionic Green's functions are provided for different directions in the frequency space.
Spectral properties of four-time fermionic Green's functions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shvaika, A. M.
The spectral relations for the four-time fermionic Green's functions are derived in the most general case. The terms which correspond to the zero-frequency anomalies, known before only for the bosonic Green's functions, are separated and their connection with the second cumulants of the Boltzmann distribution function is elucidated. Furthermore, the high-frequency expansions of the four-time fermionic Green's functions are provided for different directions in the frequency space.
Local moment relaxation in heavy-fermion compounds
DOE Office of Scientific and Technical Information (OSTI.GOV)
Simanek, E.; Sasahara, K.
1987-02-01
The Korringa relaxation rate for a local moment of an impurity in a heavy fermion compound is calculated using the model of Yoshimori and Kasai. Consistent with the recent ESR data for local moments in UBe/sub 13/, the relaxation rate is found to be unaffected by the heavy fermion renormalizations. This result can be traced to the single-site approximation and the weak k dependence of the conduction electron self-energy.
SPheno 3.1: extensions including flavour, CP-phases and models beyond the MSSM
NASA Astrophysics Data System (ADS)
Porod, W.; Staub, F.
2012-11-01
We describe recent extensions of the program SPhenoincluding flavour aspects, CP-phases, R-parity violation and low energy observables. In case of flavour mixing all masses of supersymmetric particles are calculated including the complete flavour structure and all possible CP-phases at the 1-loop level. We give details on implemented seesaw models, low energy observables and the corresponding extension of the SUSY Les Houches Accord. Moreover, we comment on the possibilities to include MSSM extensions in SPheno. Catalogue identifier: ADRV_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADRV_v2_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 154062 No. of bytes in distributed program, including test data, etc.: 1336037 Distribution format: tar.gz Programming language: Fortran95. Computer: PC running under Linux, should run in every Unix environment. Operating system: Linux, Unix. Classification: 11.6. Catalogue identifier of previous version: ADRV_v1_0 Journal reference of previous version: Comput. Phys. Comm. 153(2003)275 Does the new version supersede the previous version?: Yes Nature of problem: The first issue is the determination of the masses and couplings of supersymmetric particles in various supersymmetric models, the R-parity conserved MSSM with generation mixing and including CP-violating phases, various seesaw extensions of the MSSM and the MSSM with bilinear R-parity breaking. Low energy data on Standard Model fermion masses, gauge couplings and electroweak gauge boson masses serve as constraints. Radiative corrections from supersymmetric particles to these inputs must be calculated. Theoretical constraints on the soft SUSY breaking parameters from a high scale theory are imposed and the parameters at the electroweak scale are obtained from the high scale parameters by evaluating the corresponding renormalisation group equations. These parameters must be consistent with the requirement of correct electroweak symmetry breaking. The second issue is to use the obtained masses and couplings for calculating decay widths and branching ratios of supersymmetric particles as well as the cross sections for these particles in electron-positron annihilation. The third issue is to calculate low energy constraints in the B-meson sector such as BR(b s), MB s, rare lepton decays, such as BR(e), the SUSY contributions to anomalous magnetic moments and electric dipole moments of leptons, the SUSY contributions to the ρ parameter as well as lepton flavour violating Z decays. Solution method: The renormalisation connecting a high scale and the electroweak scale is calculated by the Runge-Kutta method. Iteration provides a solution consistent with the multi-boundary conditions. In case of three-body decays and for the calculation of initial state radiation Gaussian quadrature is used for the numerical solution of the integrals. Reasons for new version: Inclusion of new models as well as additional observables. Moreover, a new standard for data transfer had been established, which is now supported. Summary of revisions: The already existing models have been extended to include also CP-violation and flavour mixing. The data transfer is done using the so-called SLHA2 standard. In addition new models have been included: all three types of seesaw models as well as bilinear R-parity violation. Moreover, additional observables are calculated: branching ratios for flavour violating lepton decays, EDMs of leptons and of the neutron, CP-violating mass difference in the B-meson sector and branching ratios for flavour violating b-quark decays. Restrictions: In case of R-parity violation the cross sections are not calculated. Running time: 0.2 seconds on an Intel(R) Core(TM)2 Duo CPU T9900 with 3.06 GHz
How Kondo-holes create intense nanoscale heavy-fermion hybridization disorder
Hamidian, Mohammad H.; Schmidt, Andrew R.; Firmo, Inês A.; Allan, Milan P.; Bradley, Phelim; Garrett, Jim D.; Williams, Travis J.; Luke, Graeme M.; Dubi, Yonatan; Balatsky, Alexander V.; Davis, J. C.
2011-01-01
Replacing a magnetic atom by a spinless atom in a heavy-fermion compound generates a quantum state often referred to as a “Kondo-hole”. No experimental imaging has been achieved of the atomic-scale electronic structure of a Kondo-hole, or of their destructive impact [Lawrence JM, et al. (1996) Phys Rev B 53:12559–12562] [Bauer ED, et al. (2011) Proc Natl Acad Sci. 108:6857–6861] on the hybridization process between conduction and localized electrons which generates the heavy-fermion state. Here we report visualization of the electronic structure at Kondo-holes created by substituting spinless thorium atoms for magnetic uranium atoms in the heavy-fermion system URu2Si2. At each thorium atom, an electronic bound state is observed. Moreover, surrounding each thorium atom we find the unusual modulations of hybridization strength recently predicted to occur at Kondo-holes [Figgins J, Morr DK (2011) Phys Rev Lett 107:066401]. Then, by introducing the “hybridization gapmap” technique to heavy-fermion studies, we discover intense nanoscale heterogeneity of hybridization due to a combination of the randomness of Kondo-hole sites and the long-range nature of the hybridization oscillations. These observations provide direct insight into both the microscopic processes of heavy-fermion forming hybridization and the macroscopic effects of Kondo-hole doping. PMID:22006302
NASA Astrophysics Data System (ADS)
Bai, Ke-Ke; Qiao, Jia-Bin; Jiang, Hua; Liu, Haiwen; He, Lin
2017-05-01
Massless Dirac fermions in graphene provide unprecedented opportunities to realize the Klein paradox, which is one of the most exotic and striking properties of relativistic particles. In the seminal theoretical work [M. I. Katsnelson et al., Nat. Phys. 2, 620 (2006), 10.1038/nphys384], it was predicted that the massless Dirac fermions can pass through one-dimensional (1D) potential barriers unimpededly at normal incidence. Such a result seems to preclude confinement of the massless Dirac fermions in graphene by using 1D potential barriers. Here, we demonstrate both experimentally and theoretically that massless Dirac fermions can be trapped in a quasi-1D n p n junction of a continuous graphene monolayer. Because of highly anisotropic transmission of the massless Dirac fermions at n-p junction boundaries (the so-called Klein tunneling in graphene), charge carriers incident at large oblique angles will be reflected from one edge of the junction with high probability and continue to bounce from the opposite edge. Consequently, these electrons are trapped for a finite time to form quasibound states in the quasi-1D n p n junction. The quasibound states seen as pronounced resonances are probed and the quantum interference patterns arising from these states are directly visualized in our scanning tunneling microscope measurements.
Hierarchical fermions and detectable Z' from effective two-Higgs-triplet 3-3-1 model
NASA Astrophysics Data System (ADS)
Barreto, E. R.; Dias, A. G.; Leite, J.; Nishi, C. C.; Oliveira, R. L. N.; Vieira, W. C.
2018-03-01
We develop a SU (3 )C⊗SU (3 )L⊗U (1 )X model where the number of fermion generations is fixed by cancellation of gauge anomalies, being a type of 3-3-1 model with new charged leptons. Similarly to the economical 3-3-1 models, symmetry breaking is achieved effectively with two scalar triplets so that the spectrum of scalar particles at the TeV scale contains just two C P even scalars, one of which is the recently discovered Higgs boson, plus a charged scalar. Such a scalar sector is simpler than the one in the Two Higgs Doublet Model, hence more attractive for phenomenological studies, and has no flavor changing neutral currents (FCNC) mediated by scalars except for the ones induced by the mixing of Standard Model (SM) fermions with heavy fermions. We identify a global residual symmetry of the model which guarantees mass degeneracies and some massless fermions whose masses need to be generated by the introduction of effective operators. The fermion masses so generated require less fine-tuning for most of the SM fermions and FCNC are naturally suppressed by the small mixing between the third family of quarks and the rest. The effective setting is justified by an ultraviolet completion of the model from which the effective operators emerge naturally. A detailed particle mass spectrum is presented, and an analysis of the Z' production at the LHC run II is performed to show that it could be easily detected by considering the invariant mass and transverse momentum distributions in the dimuon channel.
Parity partners in the baryon resonance spectrum
Lu, Ya; Chen, Chen; Roberts, Craig D.; ...
2017-07-28
Here, we describe a calculation of the spectrum of flavor-SU(3) octet and decuplet baryons, their parity partners, and the radial excitations of these systems, made using a symmetry-preserving treatment of a vector x vector contact interaction as the foundation for the relevant few-body equations. Dynamical chiral symmetry breaking generates nonpointlike diquarks within these baryons and hence, using the contact interaction, flavor-antitriplet scalar, pseudoscalar, vector, and flavor-sextet axial-vector quark-quark correlations can all play active roles. The model yields reasonable masses for all systems studied and Faddeev amplitudes for ground states and associated parity partners that sketch a realistic picture of theirmore » internal structure: ground-state, even-parity baryons are constituted, almost exclusively, from like-parity diquark correlations, but orbital angular momentum plays an important role in the rest-frame wave functions of odd-parity baryons, whose Faddeev amplitudes are dominated by odd-parity diquarks.« less
Parity partners in the baryon resonance spectrum
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lu, Ya; Chen, Chen; Roberts, Craig D.
Here, we describe a calculation of the spectrum of flavor-SU(3) octet and decuplet baryons, their parity partners, and the radial excitations of these systems, made using a symmetry-preserving treatment of a vector x vector contact interaction as the foundation for the relevant few-body equations. Dynamical chiral symmetry breaking generates nonpointlike diquarks within these baryons and hence, using the contact interaction, flavor-antitriplet scalar, pseudoscalar, vector, and flavor-sextet axial-vector quark-quark correlations can all play active roles. The model yields reasonable masses for all systems studied and Faddeev amplitudes for ground states and associated parity partners that sketch a realistic picture of theirmore » internal structure: ground-state, even-parity baryons are constituted, almost exclusively, from like-parity diquark correlations, but orbital angular momentum plays an important role in the rest-frame wave functions of odd-parity baryons, whose Faddeev amplitudes are dominated by odd-parity diquarks.« less
Goldman, Howard H; Barry, Colleen L; Normand, Sharon-Lise T; Azzone, Vanessa; Busch, Alisa B; Huskamp, Haiden A
2012-02-01
The impact of parity coverage on the quantity of behavioral health services used by enrollees and on the prices of these services was examined in a set of Federal Employees Health Benefit (FEHB) Program plans. After parity implementation, the quantity of services used in the FEHB plans declined in five service categories, compared with plans that did not have parity coverage. The decline was significant for all service types except inpatient care. Because a previous study of the FEHB Program found that total spending on behavioral health services did not increase after parity implementation, it can be inferred that average prices must have increased over the period. The finding of a decline in service use and increase in prices provides an empirical window on what might be expected after implementation of the federal parity law and the parity requirement under the health care reform law.
What Does Mental Health Parity Really Mean for the Care of People with Serious Mental Illness?
Bartlett, John; Manderscheid, Ron
2016-06-01
Parity of mental health and substance abuse insurance benefits with medical care benefits, as well as parity in their management, are major ongoing concerns for adults with serious mental illness (SMI). The Mental Health Parity and Addiction Equity Act of 2008 guaranteed this parity of benefits and management in large private insurance plans and privately managed state Medicaid plans, but only if the benefits were offered at all. The Patient Protection and Affordable Care Act of 2010 extended parity to all persons receiving insurance through the state health insurance marketplaces, through the state Medicaid Expansions, and through new individual and small group plans. This article presents an analysis of how accessible parity has become for adults with SMI at both the system and personal levels several years after these legislative changes have been implemented. Copyright © 2016 Elsevier Inc. All rights reserved.
Can R-parity violation hide vanilla supersymmetry at the LHC?
NASA Astrophysics Data System (ADS)
Asano, Masaki; Rolbiecki, Krzysztof; Sakurai, Kazuki
2013-01-01
Current experimental constraints on a large parameter space in supersymmetric models rely on the large missing energy signature. This is usually provided by the lightest neutralino which stability is ensured by R-parity. However, if R-parity is violated, the lightest neutralino decays into the standard model particles and the missing energy cut is not efficient anymore. In particular, the U DD type R-parity violation induces the neutralino decay to three quarks which potentially leads to the most difficult signal to be searched at hadron colliders. In this paper, we study the constraints on R-parity violating supersymmetric models using a same-sign dilepton and a multijet signatures. We show that the gluino and squarks lighter than TeV are already excluded in the constrained minimal supersymmetric standard model with the R-parity violation if their masses are approximately equal. We also analyze constraints in a simplified model with the R-parity violation. We compare how the R-parity violation changes some of the observables typically used to distinguish a supersymmetric signal from standard model backgrounds.
The effect of parity on expenditures for individuals with severe mental illness.
McConnell, K John
2013-10-01
To determine whether comprehensive behavioral health parity leads to changes in expenditures for individuals with severe mental illness (SMI), who are likely to be in greatest need for services that could be outside of health plans' traditional limitations on behavioral health care. We studied the effects of a comprehensive parity law enacted by Oregon in 2007. Using claims data, we compared expenditures for individuals in four Oregon commercial plans from 2005 through 2008 to a group of commercially insured individuals in Oregon who were exempt from parity. We used difference-in-differences and difference-in-difference-in-differences analyses to estimate changes in spending, and quantile regression methods to assess changes in the distribution of expenditures associated with parity. Among 2,195 individuals with SMI, parity was associated with increased expenditures for behavioral health services of $333 (95 percent CI $67, $615), without corresponding increases in out-of-pocket spending. The increase in expenditures was primarily attributable to shifts in the right tail of the distribution. Oregon's parity law led to higher average expenditures for individuals with SMI. Parity may allow individuals with high mental health needs to receive services that may have been limited without parity regulations. © Health Research and Educational Trust.
Iowa State University – Final Report for SciDAC3/NUCLEI
DOE Office of Scientific and Technical Information (OSTI.GOV)
Vary, James P
The Iowa State University (ISU) contributions to the NUCLEI project are focused on developing, implementing and running an efficient and scalable configuration interaction code (Many-Fermion Dynamics – nuclear or MFDn) for leadership class supercomputers addressing forefront research problems in low-energy nuclear physics. We investigate nuclear structure and reactions with realistic nucleon-nucleon (NN) and three-nucleon (3N) interactions. We select a few highlights from our work that has produced a total of more than 82 refereed publications and more than 109 invited talks under SciDAC3/NUCLEI.
NASA Astrophysics Data System (ADS)
Valkov, V. V.; Dzebisashvili, D. M.; Barabanov, A. F.
2017-05-01
The spin-fermion model, which is an effective low-energy realization of the three-band Emery model after passing to the Wannier representation for the px and py orbitals of the subsystem of oxygen ions, reduces to the generalized Kondo lattice model. A specific feature of this model is the existence of spin-correlated hoppings of the current carriers between distant cells. Numerical calculations of the spectrum of spin-electron excitations highlight the important role of the long-range spin-correlated hoppings.
The association between parity and birthweight in a longitudinal consecutive pregnancy cohort.
Hinkle, Stefanie N; Albert, Paul S; Mendola, Pauline; Sjaarda, Lindsey A; Yeung, Edwina; Boghossian, Nansi S; Laughon, S Katherine
2014-03-01
Nulliparity is associated with lower birthweight, but few studies have examined how within-mother changes in risk factors impact this association. We used longitudinal electronic medical record data from a hospital-based cohort of consecutive singleton live births from 2002-2010 in Utah. To reduce bias from unobserved pregnancies, primary analyses were limited to 9484 women who entered nulliparous from 2002-2004, with 23,380 pregnancies up to parity 3. Unrestricted secondary analyses used 101,225 pregnancies from 45,212 women with pregnancies up to parity 7. We calculated gestational age and sex-specific birthweight z-scores with nulliparas as the reference. Using linear mixed models, we estimated birthweight z-score by parity adjusting for pregnancy-specific sociodemographics, smoking, alcohol, prepregnancy body mass index, gestational weight gain, and medical conditions. Compared with nulliparas', infants of primiparas were larger by 0.20 unadjusted z-score units [95% confidence interval (CI) 0.18, 0.22]; the adjusted increase was similar at 0.18 z-score units [95% CI 0.15, 0.20]. Birthweight continued to increase up to parity 3, but with a smaller difference (parity 3 vs. 0 β = 0.27 [95% CI 0.20, 0.34]). In the unrestricted secondary sample, there was significant departure in linearity from parity 1 to 7 (P < 0.001); birthweight increased only up to parity 4 (parity 4 vs. 0 β = 0.34 [95% CI 0.31, 0.37]). The association between parity and birthweight was non-linear with the greatest increase observed between first- and second-born infants of the same mother. Adjustment for changes in weight or chronic diseases did not change the relationship between parity and birthweight. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Allali, Fadoua; Maaroufi, Houda; Aichaoui, Siham El; Khazani, Hamza; Saoud, Bouchra; Benyahya, Boubker; Abouqal, Redouane; Hajjaj-Hassouni, Najia
2007-08-20
The aims of the study were to determine: (1) the relationship between parity and bone mineral density (BMD); (2) the relationship between parity and osteoporotic peripheral fractures. The group studied included 730 postmenopausal women. Patients were separated into four groups according to the number of fullterm pregnancies, group 1: nulliparae, group 2: one to three pregnancies, group 3: four to five pregnancies, and group 4: six and more pregnancies. Additionally, patients were separated into three groups according to their ages, as <50 years, 50-59 years and >or=60 years. The median parity was 4 [0-20]. All the patients with parity greater than six had spine and hip BMD values significantly lower than values in the other groups (p<0.001). After adjustment for age and body mass index (BMI), decreased lumbar and total hip BMD were still associated to increased parity (analysis of covariance (ANCOVA), p=0.04 and 0.023, respectively). The relation between parity and lumbar BMD was highly significant among women aged <50 years (age-adjusted p=0.022), while there was no parity-spine BMD association in the other age groups. The relation between parity and hip BMD was seen only in the group 50-59 years (age-adjusted p=0.042). A positive history for peripheral fractures was present in 170 (23%) patients. There was relationship between parity and peripheral fractures neither in the whole population nor in the sub-groups according to age. The present study suggests that the BMD of the spine and hip decreases with an increasing number of pregnancies, and this situation shows variations in different age groups. However, there was no correlation between parity level and peripheral fractures.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yang, Zili; Nordhaus, William
2009-03-19
In the duration of this project, we finished the main tasks set up in the initial proposal. These tasks include: setting up the basic platform in GAMS language for the new RICE 2007 model; testing various model structure of RICE 2007; incorporating PPP data set in the new RICE model; developing gridded data set for IA modeling.
Did Caravaggio employ optical projections? An image analysis of the parity in the artist's paintings
NASA Astrophysics Data System (ADS)
Stork, David G.
2011-03-01
We examine one class of evidence put forth in support of the recent claim that the Italian Baroque master Caravaggio secretly employed optical projectors as a direct drawing aid. Specically, we test the claims that there is an "abnormal number" of left-handed gures in his works and, more specically, that "During the Del Monte period he had too many left-handed models." We also test whether there was a reversal in the handedness of specic models in different paintings. Such evidence would be consistent with the claim that Caravaggio switched between using a convex-lens projector to using a concave-mirror projector and would support, but not prove, the claim that Caravaggio used optical projections. We estimate the parity (+ or -) of each of Caravaggio's 76 appropriate oil paintings based on the handedness of gures, the orientation of asymmetric objects, placement of scabbards, depicted text, and so on, and search for statistically significant changes in handedness in figures. We also track the direction of the illumination over time in the artist's uvre. We discuss some historical evidence as it relates to the question of his possible use of optics. We nd the proportion of left-handed figures lower than that in the general population (not higher), and no significant change in estimated handedness even of individual models. Optical proponents have argued that Bacchus (1597) portrays a left-handed gure, but we give visual and cultural evidence showing that this gure is instead right-handed, thereby rebutting this claim that the painting was executed using optical projections. Moreover, scholars recently re-discovered the image of the artist with easel and canvas reflected in the carafe of wine at the front left in the tableau in Bacchus, showing that this painting was almost surely executed using traditional (non-optical) easel methods. We conclude that there is 1) no statistically signicant abnormally high number of left-handed gures in Caravaggio's uvre, including during any limited working period, 2) no statistically significant change in handedness among all gures or even individual gures that might be consistent with a change in optical projector, and 3) the visual and cultural evidence in Bacchus shows the gure was right-handed and that the artist executed this work by traditional (non-optical) easel methods. We conclude that the general parity and handedness evidence does not support the claim that Caravaggio employed optical projections.
Rajan, Sowmya; Nanda, Priya; Calhoun, Lisa M; Speizer, Ilene S
2018-02-27
The sex composition of existing children has been shown to influence childbearing decision-making and behaviors of women and couples. One aspect of this influence is the preference for sons. In India, where son preference is deeply entrenched, research has normally focused on rural areas using cross-sectional data. However, urban areas in India are rapidly changing, with profound implications for childbearing patterns. Yet, evidence on the effect of the sex composition of current children on subsequent childbearing intentions and behavior in urban areas is scant. In this study, we analyze the impact of sex composition of children on subsequent (1) parity progression, (2) contraceptive use, and (3) desire for another child. We analyze prospective data from women over a four year period in urban Uttar Pradesh using discrete-time event history logistic regression models to analyze parity progression from the first to second parity, second to third parity, and third to fourth parity. We also use logistic regression models to analyze contraceptive use and desire for another child. Relative to women with no daughters, women with no sons had significantly higher odds of progressing to the next birth (parity 1 - aOR: 1.31; CI: 1.04-1.66; parity 2 - aOR: 4.65; CI: 3.11-6.93; parity 3 - aOR:3.45; CI: 1.83-6.52), as well as reduced odds of using contraception (parity 2 - aOR:.58; CI: .44-.76; parity 3 - aOR: .58; CI: .35-.98). Relative to women with two or more sons, women with two or more daughters had significantly higher odds of wanting to have another child (parity 1 - aOR: 1.33; CI: 1.06-1.67; parity 2 - aOR: 3.96; CI: 2.45-6.41; parity 3-4.89; CI: 2.22-10.77). Our study demonstrates the pervasiveness of son preference in urban areas of Uttar Pradesh. We discuss these findings for future programmatic strategies to mitigate son preference in urban settings.
Togashi, K; Lin, C Y
2008-07-01
The objective of this study was to compare 6 selection criteria in terms of 3-parity total milk yield and 9 selection criteria in terms of total net merit (H) comprising 3-parity total milk yield and total lactation persistency. The 6 selection criteria compared were as follows: first-parity milk estimated breeding value (EBV; M1), first 2-parity milk EBV (M2), first 3-parity milk EBV (M3), first-parity eigen index (EI(1)), first 2-parity eigen index (EI(2)), and first 3-parity eigen index (EI(3)). The 9 selection criteria compared in terms of H were M1, M2, M3, EI(1), EI(2), EI(3), and first-parity, first 2-parity, and first 3-parity selection indices (I(1), I(2), and I(3), respectively). In terms of total milk yield, selection on M3 or EI(3) achieved the greatest genetic response, whereas selection on EI(1) produced the largest genetic progress per day. In terms of total net merit, selection on I(3) brought the largest response, whereas selection EI(1) yielded the greatest genetic progress per day. A multiple-lactation random regression test-day model simultaneously yields the EBV of the 3 lactations for all animals included in the analysis even though the younger animals do not have the opportunity to complete the first 3 lactations. It is important to use the first 3 lactation EBV for selection decision rather than only the first lactation EBV in spite of the fact that the first-parity selection criteria achieved a faster genetic progress per day than the 3-parity selection criteria. Under a multiple-lactation random regression animal model analysis, the use of the first 3 lactation EBV for selection decision does not prolong the generation interval as compared with the use of only the first lactation EBV. Thus, it is justified to compare genetic response on a lifetime basis rather than on a per-day basis. The results suggest the use of M3 or EI(3) for genetic improvement of total milk yield and the use of I(3) for genetic improvement of total net merit H. Although this study deals with selection for 3-parity milk production, the same principle applies to selection for lifetime milk production.
The Fermionic Signature Operator and Hadamard States in the Presence of a Plane Electromagnetic Wave
NASA Astrophysics Data System (ADS)
Finster, Felix; Reintjes, Moritz
2017-05-01
We give a non-perturbative construction of a distinguished state for the quantized Dirac field in Minkowski space in the presence of a time-dependent external field of the form of a plane electromagnetic wave. By explicit computation of the fermionic signature operator, it is shown that the Dirac operator has the strong mass oscillation property. We prove that the resulting fermionic projector state is a Hadamard state.
Staggered fermions, zero modes, and flavor-singlet mesons
Donald, Gordon C; Davies, Christine T.H.; Follana, Eduardo; ...
2011-09-12
We examine the taste structure of eigenvectors of the staggered-fermion Dirac operator. We derive a set of conditions on the eigenvectors of modes with small eigenvalues (near-zero modes), such that staggered fermions reproduce the 't Hooft vertex in the continuum limit. We also show that, assuming these conditions, the correlators of flavor-singlet mesons are free of contributions singular in 1/m, where m is the quark mass. This conclusion holds also when a single flavor of sea quark is represented by the fourth root of the staggered-fermion determinant. We then test numerically, using the HISQ action, whether these conditions hold onmore » realistic lattice gauge fields. We find that the needed structure does indeed emerge.« less
Counting local integrals of motion in disordered spinless-fermion and Hubbard chains
NASA Astrophysics Data System (ADS)
Mierzejewski, Marcin; Kozarzewski, Maciej; Prelovšek, Peter
2018-02-01
We develop a procedure which systematically generates all conserved operators in the disordered models of interacting fermions. Among these operators, we identify and count the independent and local integrals of motion (LIOM), which represent the hallmark of the many-body localization (MBL). The method is tested first on the prototype disordered chain of interacting spinless fermions. As expected for full MBL, we find for large enough disorder NM=2M-1 independent and quasilocal LIOM with support on M consecutive sites. On the other hand, the study of the disordered Hubbard chain reveals that 3M-1
Split Orthogonal Group: A Guiding Principle for Sign-Problem-Free Fermionic Simulations
NASA Astrophysics Data System (ADS)
Wang, Lei; Liu, Ye-Hua; Iazzi, Mauro; Troyer, Matthias; Harcos, Gergely
2015-12-01
We present a guiding principle for designing fermionic Hamiltonians and quantum Monte Carlo (QMC) methods that are free from the infamous sign problem by exploiting the Lie groups and Lie algebras that appear naturally in the Monte Carlo weight of fermionic QMC simulations. Specifically, rigorous mathematical constraints on the determinants involving matrices that lie in the split orthogonal group provide a guideline for sign-free simulations of fermionic models on bipartite lattices. This guiding principle not only unifies the recent solutions of the sign problem based on the continuous-time quantum Monte Carlo methods and the Majorana representation, but also suggests new efficient algorithms to simulate physical systems that were previously prohibitive because of the sign problem.
Particlelike solutions of the Einstein-Dirac equations
NASA Astrophysics Data System (ADS)
Finster, Felix; Smoller, Joel; Yau, Shing-Tung
1999-05-01
The coupled Einstein-Dirac equations for a static, spherically symmetric system of two fermions in a singlet spinor state are derived. Using numerical methods, we construct an infinite number of solitonlike solutions of these equations. The stability of the solutions is analyzed. For weak coupling (i.e., small rest mass of the fermions), all the solutions are linearly stable (with respect to spherically symmetric perturbations), whereas for stronger coupling, both stable and unstable solutions exist. For the physical interpretation, we discuss how the energy of the fermions and the (ADM) mass behave as functions of the rest mass of the fermions. Although gravitation is not renormalizable, our solutions of the Einstein-Dirac equations are regular and well behaved even for strong coupling.
Magnetotransport in Layered Dirac Fermion System Coupled with Magnetic Moments
NASA Astrophysics Data System (ADS)
Iwasaki, Yoshiki; Morinari, Takao
2018-03-01
We theoretically investigate the magnetotransport of Dirac fermions coupled with localized moments to understand the physical properties of the Dirac material EuMnBi2. Using an interlayer hopping form, which simplifies the complicated interaction between the layers of Dirac fermions and the layers of magnetic moments in EuMnBi2, the theory reproduces most of the features observed in this system. The hysteresis observed in EuMnBi2 can be caused by the valley splitting that is induced by the spin-orbit coupling and the external magnetic field with the molecular field created by localized moments. Our theory suggests that the magnetotransport in EuMnBi2 is due to the interplay among Dirac fermions, localized moments, and spin-orbit coupling.
Electrodynamic response of the type-II Weyl semimetal YbMnBi 2
Chinotti, M.; Pal, A.; Ren, W. J.; ...
2016-12-01
Weyl fermions play a major role in quantum field theory but have been quite elusive as fundamental particles. These quasi-two-dimensional bismuth layers based materials were recently designed and provide an arena for studying the interplay between anisotropic Dirac fermions, magnetism, and structural changes, allowing the formation of Weyl fermions in condensed matter. We perform an optical investigation of YbMnBi 2 , a representative type-II Weyl semimetal, and contrast its excitation spectrum with the optical response of the more conventional semimetal EuMnBi 2 . This comparative study allows us to disentangle the optical fingerprints of type-II Weyl fermions, but also challengesmore » the present theoretical understanding of their electrodynamic response.« less
7 CFR 5.5 - Publication of season average, calendar year, and parity price data.
Code of Federal Regulations, 2010 CFR
2010-01-01
... cases where preliminary marketing season average price data are used in estimating the adjusted base... parity price data. 5.5 Section 5.5 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.5 Publication of season average, calendar year, and parity price data. (a) New adjusted...
ERIC Educational Resources Information Center
Bozalek, Vivienne
2011-01-01
This article proposes a model for judging children's participatory parity in different social spaces. The notion of participatory parity originates in Nancy Fraser's normative theory for social justice, where it concerns the participatory status of adults. What, then, constitutes participatory parity for children? How should we judge the extent to…
Long-lived stop at the LHC with or without R-parity
DOE Office of Scientific and Technical Information (OSTI.GOV)
Covi, L.; Dradi, F., E-mail: laura.covi@theorie.physik.uni-goettingen.de, E-mail: federico.dradi@theorie.physik.uni-goettingen.de
2014-10-01
We consider scenarios of gravitino LSP and DM with stop NLSP both within R-parity conserving and R-parity violating supersymmetry (RPC and RPV SUSY, respectively). We discuss cosmological bounds from Big Bang Nucleosynthesis (BBN) and the gravitino abundance and then concentrate on the signals of long-lived stops at the LHC as displaced vertices or metastable particles. Finally we discuss how to distinguish R-parity conserving and R-parity breaking stop decays if they happen within the detector and how to suppress SM backgrounds.
The economic consequences of neurosurgical disease in low- and middle-income countries.
Rudolfson, Niclas; Dewan, Michael C; Park, Kee B; Shrime, Mark G; Meara, John G; Alkire, Blake C
2018-05-18
OBJECTIVE The objective of this study was to estimate the economic consequences of neurosurgical disease in low- and middle-income countries (LMICs). METHODS The authors estimated gross domestic product (GDP) losses and the broader welfare losses attributable to 5 neurosurgical disease categories in LMICs using two distinct economic models. The value of lost output (VLO) model projects annual GDP losses due to neurosurgical disease during 2015-2030, and is based on the WHO's "Projecting the Economic Cost of Ill-health" tool. The value of lost economic welfare (VLW) model estimates total welfare losses, which is based on the value of a statistical life and includes nonmarket losses such as the inherent value placed on good health, resulting from neurosurgical disease in 2015 alone. RESULTS The VLO model estimates the selected neurosurgical diseases will result in $4.4 trillion (2013 US dollars, purchasing power parity) in GDP losses during 2015-2030 in the 90 included LMICs. Economic losses are projected to disproportionately affect low- and lower-middle-income countries, risking up to a 0.6% and 0.54% loss of GDP, respectively, in 2030. The VLW model evaluated 127 LMICs, and estimates that these countries experienced $3 trillion (2013 US dollars, purchasing power parity) in economic welfare losses in 2015. Regardless of the model used, the majority of the losses can be attributed to stroke and traumatic brain injury. CONCLUSIONS The economic impact of neurosurgical diseases in LMICs is significant. The magnitude of economic losses due to neurosurgical diseases in LMICs provides further motivation beyond already compelling humanitarian reasons for action.
Gröbner bases for finite-temperature quantum computing and their complexity
NASA Astrophysics Data System (ADS)
Crompton, P. R.
2011-11-01
Following the recent approach of using order domains to construct Gröbner bases from general projective varieties, we examine the parity and time-reversal arguments relating to the Wightman axioms of quantum field theory and propose that the definition of associativity in these axioms should be introduced a posteriori to the cluster property in order to generalize the anyon conjecture for quantum computing to indefinite metrics. We then show that this modification, which we define via ideal quotients, does not admit a faithful representation of the Braid group, because the generalized twisted inner automorphisms that we use to reintroduce associativity are only parity invariant for the prime spectra of the exterior algebra. We then use a coordinate prescription for the quantum deformations of toric varieties to show how a faithful representation of the Braid group can be reconstructed and argue that for a degree reverse lexicographic (monomial) ordered Gröbner basis, the complexity class of this problem is bounded quantum polynomial.
NASA Astrophysics Data System (ADS)
Foster, Kerwin Crayton
The fractional quantum Hall effect (FQHE) occurs when a two-dimensional electron gas is placed in a strong magnetic field at low temperatures. When this effect occurs the Hall resistance, RH, defined to be the Hall voltage divided by the current, is quantized, with RH = (1/nu)h/ e2 where nu = p/q is the Landau level filling fraction; and p and q are relatively prime integers. For almost all observed FQHE states, q is odd with one notable exception: the nu = 5/2 FQHE state. Understanding the nature of this incompressible even-denominator state is one of the central questions in the theory of the FQHE and is the subject of this Dissertation. We use a powerful theoretical tool for studying the FQHE: composite fermion theory. Composite fermions can be viewed as electrons bound to an even number of magnetic flux quanta. Jain has shown that the FQHE for electrons can be viewed as an integer quantum Hall effect (p = 1) for composite fermions. More recently, Halperin, Lee and Read developed a successful theory of the compressible nu = 1/2 state using composite fermions. There is now compelling theoretical evidence that the 5/2 state is a so-called Moore-Read state---a state which can be viewed as a spin-polarized p-wave superconductor of composite fermions. We have developed a semi-phenomenological description of this state by modifying the Halperin-Lee-Read theory, adding a p-wave pairing interaction between composite fermions by hand. The electromagnetic response functions for the resulting superconducting state of composite fermions are then calculated. We show that these response functions exhibit the expected BCS 'coherence factor' effects, such as the Hebel-Slichter peak. Using the composite fermion response functions, we then calculate the corresponding electronic response functions using Chern-Simons theory. We find that in the electronic response, the most striking coherence factor effects (e.g., the Hebel-Slichter peak) are strongly suppressed. However, the low-temperature o = 2Delta threshold behavior does show clear coherence factor effects. Finally, we use our model to predict the wave-vector and frequency dependence of the longitudinal conductivity, sigmaxx( q, o), which can be measured in surface-acoustic-wave propagation experiments.
NASA Technical Reports Server (NTRS)
Strecker, Kevin; Truscott, Andrew; Partridge, Guthrie; Chen, Ying-Cheng
2003-01-01
Dual evaporation gives 50 million fermions at T = 0.1 T(sub F). Demonstrated suppression of interactions by coherent superposition - applicable to atomic clocks. Looking for evidence of Cooper pairing and superfluidity.
Fermionic influence on inflationary fluctuations
NASA Astrophysics Data System (ADS)
Boyanovsky, Daniel
2016-04-01
Motivated by apparent persistent large scale anomalies in the cosmic microwave background we study the influence of fermionic degrees of freedom on the dynamics of inflaton fluctuations as a possible source of violations of (nearly) scale invariance on cosmological scales. We obtain the nonequilibrium effective action of an inflaton-like scalar field with Yukawa interactions (YD ,M) to light fermionic degrees of freedom both for Dirac and Majorana fields in de Sitter space-time. The effective action leads to Langevin equations of motion for the fluctuations of the inflaton-like field, with self-energy corrections and a stochastic Gaussian noise. We solve the Langevin equation in the super-Hubble limit implementing a dynamical renormalization group resummation. For a nearly massless inflaton its power spectrum of super-Hubble fluctuations is enhanced, P (k ;η )=(H/2 π )2eγt[-k η ] with γt[-k η ]=1/6 π2 [∑i =1 NDYi,D 2+2 ∑j =1 NMYj,M 2]{ln2[-k η ]-2 ln [-k η ]ln [-k η0]} for ND Dirac and NM Majorana fermions, and η0 is the renormalization scale at which the inflaton mass vanishes. The full power spectrum is shown to be renormalization group invariant. These corrections to the super-Hubble power spectrum entail a violation of scale invariance as a consequence of the coupling to the fermionic fields. The effective action is argued to be exact in the limit of a large number of fermionic fields. A cancellation between the enhancement from fermionic degrees of freedom and suppression from light scalar degrees of freedom conformally coupled to gravity suggests the possibility of a finely tuned supersymmetry among these fields.
Foundations of heavy-fermion superconductivity: lattice Kondo effect and Mott physics.
Steglich, Frank; Wirth, Steffen
2016-08-01
This article overviews the development of heavy-fermion superconductivity, notably in such rare-earth-based intermetallic compounds which behave as Kondo-lattice systems. Heavy-fermion superconductivity is of unconventional nature in the sense that it is not mediated by electron-phonon coupling. Rather, in most cases the attractive interaction between charge carriers is apparently magnetic in origin. Fluctuations associated with an antiferromagnetic (AF) quantum critical point (QCP) play a major role. The first heavy-fermion superconductor CeCu2Si2 turned out to be the prototype of a larger group of materials for which the underlying, often pressure-induced, AF QCP is likely to be of a three-dimensional (3D) spin-density-wave (SDW) variety. For UBe13, the second heavy-fermion superconductor, a magnetic-field-induced 3D SDW QCP inside the superconducting phase can be conjectured. Such a 'conventional', itinerant QCP can be well understood within Landau's paradigm of order-parameter fluctuations. In contrast, the low-temperature normal-state properties of a few heavy-fermion superconductors are at odds with the Landau framework. They are characterized by an 'unconventional', local QCP which may be considered a zero-temperature 4 f-orbital selective Mott transition. Here, as concluded for YbRh2Si2, the breakdown of the Kondo effect concurring with the AF instability gives rise to an abrupt change of the Fermi surface. Very recently, superconductivity was discovered for this compound at ultra-low temperatures. Therefore, YbRh2Si2 along with CeRhIn5 under pressure provide a natural link between the large group of about fifty low-temperature heavy-fermion superconductors and other families of unconventional superconductors with substantially higher T c, e.g. the doped Mott insulators of the perovskite-type cuprates and the organic charge-transfer salts.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brinckmann, Jan; Woelfle, Peter
2004-11-01
The nearest-neighbor quantum antiferromagnetic (AF) Heisenberg model for spin-1/2 on a two-dimensional square lattice is studied in the auxiliary-fermion representation. Expressing spin operators by canonical fermionic particles requires a constraint on the fermion charge Q{sub i}=1 on each lattice site i, which is imposed approximately through the thermal average. The resulting interacting fermion system is first treated in mean-field theory (MFT), which yields an AF ordered ground state and spin waves in quantitative agreement with conventional spin-wave theory. At finite temperature a self-consistent approximation beyond mean field is required in order to fulfill the Mermin-Wagner theorem. We first discuss amore » fully self-consistent approximation, where fermions are renormalized due to fluctuations of their spin density, in close analogy to FLEX. While static properties like the correlation length, {xi}(T){proportional_to}exp(aJ/T), come out correctly, the dynamical response lacks the magnon-like peaks which would reflect the appearance of short-range order at low T. This drawback, which is caused by overdamping, is overcome in a 'minimal self-consistent approximation' (MSCA), which we derive from the equations of motion. The MSCA features dynamical scaling at small energy and temperature and is qualitatively correct both in the regime of order-parameter relaxation at long wavelengths {lambda}>{xi} and in the short-range-order regime at {lambda}<{xi}. We also discuss the impact of vertex corrections and the problem of pseudo-gap formation in the single-particle density of states due to long-range fluctuations. Finally we show that the (short-range) magnetic order in MFT and MSCA helps to fulfill the constraint on the local fermion occupancy.« less
Faust, M A; Robison, O W; Tess, M W
1992-07-01
A stochastic life-cycle swine production model was used to study the effect of female replacement rates in the dam-daughter pathway for a tiered breeding structure on genetic change and returns to the breeder. Genetic, environmental, and economic parameters were used to simulate characteristics of individual pigs in a system producing F1 female replacements. Evaluated were maximum culling ages for nucleus and multiplier tier sows. System combinations included one- and five-parity alternatives for both levels and 10-parity options for the multiplier tier. Yearly changes and average phenotypic levels were computed for performance and economic measures. Generally, at the nucleus level, responses to 10 yr of selection for sow and pig performance in five-parity herds were 70 to 85% of response in one-parity herds. Similarly, the highest selection responses in multiplier herds were from systems with one-parity nucleus tiers. Responses in these were typically greater than 115% of the response for systems with the smallest yearly change, namely, the five-parity nucleus and five- and 10-parity multiplier levels. In contrast, the most profitable multiplier tiers (10-parity) had the lowest replacement costs. Within a multiplier culling strategy, rapid genetic change was desirable. Differences between systems that culled after five or 10 parities were smaller than differences between five- and one-parity multiplier options. To recover production costs, systems with the lowest returns required 140% of market hog value for gilts available to commercial tiers, whereas more economically efficient systems required no premium.
Wallace, Neal T; McConnell, K John
2013-10-01
This study assessed the impact of Oregon's 2007 parity law, which required behavioral health insurance parity, on rates of follow-up care provided within 30 days of psychiatric inpatient care. Data sources were claims (2005-2008) for 737 individuals with inpatient stays for a mental disorder who were continuously enrolled in insurance plans affected by the parity law (intervention group) or in commercial, self-insured plans that were not affected by the law (control group). A difference-in-difference analysis was used to compare rates of follow-up care before and after the parity law between discharges of individuals in the intervention group and the control group and between discharges of individuals in the intervention group who had or had not met preparity quantitative coverage limits during a coverage year. Estimates of the marginal effects of the parity law were adjusted for gender, discharge diagnosis, relationship to policy holder, and calendar quarter of discharge. The study included 353 discharges in the intervention group and 535 discharges in the control group. After the parity law, follow-up rates increased by 11% (p=.042) overall and by 20% for discharges of individuals who had met coverage limits (p=.028). The Oregon parity law was associated with a large increase in the rate of follow-up care, predominantly for discharges of individuals who had met preparity quantitative coverage limits. Given similarities between the law and the 2008 Mental Health Parity and Addiction Equity Act, the results may portend a national effect of more comprehensive parity laws.
Unitarity violation in noninteger dimensional Gross-Neveu-Yukawa model
NASA Astrophysics Data System (ADS)
Ji, Yao; Kelly, Michael
2018-05-01
We construct an explicit example of unitarity violation in fermionic quantum field theories in noninteger dimensions. We study the two-point correlation function of four-fermion operators. We compute the one-loop anomalous dimensions of these operators in the Gross-Neveu-Yukawa model. We find that at one-loop order, the four-fermion operators split into three classes with one class having negative norms. This implies that the theory violates unitarity, following the definition in Ref. [1].
Unconventional States of Matter with Cold Atoms and Dipolar Molecules
2014-08-20
ferromagnetic state. For alkaline-earth fermions, the large SU(2N) symmetry greatly enhances quantum spin fluctuations, which give rises to novel...both bosons and fermions, novel quantum magnetism with large spin SU(2N) al- kaline fermions, novel topological states with synthetic gauge fields...presented in Sect. 1.1. The study of novel quantum magnetism with large spin alkaline earth atoms is presented in Sect. 1.2. In Sect. 1.3, we present our
Fermion-to-qubit mappings with varying resource requirements for quantum simulation
NASA Astrophysics Data System (ADS)
Steudtner, Mark; Wehner, Stephanie
2018-06-01
The mapping of fermionic states onto qubit states, as well as the mapping of fermionic Hamiltonian into quantum gates enables us to simulate electronic systems with a quantum computer. Benefiting the understanding of many-body systems in chemistry and physics, quantum simulation is one of the great promises of the coming age of quantum computers. Interestingly, the minimal requirement of qubits for simulating Fermions seems to be agnostic of the actual number of particles as well as other symmetries. This leads to qubit requirements that are well above the minimal requirements as suggested by combinatorial considerations. In this work, we develop methods that allow us to trade-off qubit requirements against the complexity of the resulting quantum circuit. We first show that any classical code used to map the state of a fermionic Fock space to qubits gives rise to a mapping of fermionic models to quantum gates. As an illustrative example, we present a mapping based on a nonlinear classical error correcting code, which leads to significant qubit savings albeit at the expense of additional quantum gates. We proceed to use this framework to present a number of simpler mappings that lead to qubit savings with a more modest increase in gate difficulty. We discuss the role of symmetries such as particle conservation, and savings that could be obtained if an experimental platform could easily realize multi-controlled gates.
New directions in the pursuit of Majorana fermions in solid state systems.
Alicea, Jason
2012-07-01
The 1937 theoretical discovery of Majorana fermions-whose defining property is that they are their own anti-particles-has since impacted diverse problems ranging from neutrino physics and dark matter searches to the fractional quantum Hall effect and superconductivity. Despite this long history the unambiguous observation of Majorana fermions nevertheless remains an outstanding goal. This review paper highlights recent advances in the condensed matter search for Majorana that have led many in the field to believe that this quest may soon bear fruit. We begin by introducing in some detail exotic 'topological' one- and two-dimensional superconductors that support Majorana fermions at their boundaries and at vortices. We then turn to one of the key insights that arose during the past few years; namely, that it is possible to 'engineer' such exotic superconductors in the laboratory by forming appropriate heterostructures with ordinary s-wave superconductors. Numerous proposals of this type are discussed, based on diverse materials such as topological insulators, conventional semiconductors, ferromagnetic metals and many others. The all-important question of how one experimentally detects Majorana fermions in these setups is then addressed. We focus on three classes of measurements that provide smoking-gun Majorana signatures: tunneling, Josephson effects and interferometry. Finally, we discuss the most remarkable properties of condensed matter Majorana fermions-the non-Abelian exchange statistics that they generate and their associated potential for quantum computation.
NASA Astrophysics Data System (ADS)
Wehling, T. O.; Black-Schaffer, A. M.; Balatsky, A. V.
2014-01-01
A wide range of materials, like d-wave superconductors, graphene, and topological insulators, share a fundamental similarity: their low-energy fermionic excitations behave as massless Dirac particles rather than fermions obeying the usual Schrodinger Hamiltonian. This emergent behavior of Dirac fermions in condensed matter systems defines the unifying framework for a class of materials we call "Dirac materials''. In order to establish this class of materials, we illustrate how Dirac fermions emerge in multiple entirely different condensed matter systems and we discuss how Dirac fermions have been identified experimentally using electron spectroscopy techniques (angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy). As a consequence of their common low-energy excitations, this diverse set of materials shares a significant number of universal properties in the low-energy (infrared) limit. We review these common properties including nodal points in the excitation spectrum, density of states, specific heat, transport, thermodynamic properties, impurity resonances, and magnetic field responses, as well as discuss many-body interaction effects. We further review how the emergence of Dirac excitations is controlled by specific symmetries of the material, such as time-reversal, gauge, and spin-orbit symmetries, and how by breaking these symmetries a finite Dirac mass is generated. We give examples of how the interaction of Dirac fermions with their distinct real material background leads to rich novel physics with common fingerprints such as the suppression of back scattering and impurity-induced resonant states.
Thermoelectric Transport Signatures of Dirac Composite Fermions in the Half-Filled Landau Level
NASA Astrophysics Data System (ADS)
Potter, Andrew C.; Serbyn, Maksym; Vishwanath, Ashvin
2016-07-01
The half-filled Landau level is expected to be approximately particle-hole symmetric, which requires an extension of the Halperin-Lee-Read (HLR) theory of the compressible state observed at this filling. Recent work indicates that, when particle-hole symmetry is preserved, the composite fermions experience a quantized π -Berry phase upon winding around the composite Fermi surface, analogous to Dirac fermions at the surface of a 3D topological insulator. In contrast, the effective low-energy theory of the composite fermion liquid originally proposed by HLR lacks particle-hole symmetry and has vanishing Berry phase. In this paper, we explain how thermoelectric transport measurements can be used to test the Dirac nature of the composite fermions by quantitatively extracting this Berry phase. First, we point out that longitudinal thermopower (Seebeck effect) is nonvanishing because of the unusual nature of particle-hole symmetry in this context and is not sensitive to the Berry phase. In contrast, we find that off-diagonal thermopower (Nernst effect) is directly related to the topological structure of the composite Fermi surface, vanishing for zero Berry phase and taking its maximal value for π Berry phase. In contrast, in purely electrical transport signatures, the Berry phase contributions appear as small corrections to a large background signal, making the Nernst effect a promising diagnostic of the Dirac nature of composite fermions.
7 CFR 5.1 - Parity index and index of prices received by farmers.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 7 Agriculture 1 2010-01-01 2010-01-01 false Parity index and index of prices received by farmers... § 5.1 Parity index and index of prices received by farmers. (a) The parity index and related indices... farmers, interest, taxes, and farm wage rates, as revised May 1976 and published in the May 28, 1976, and...
First measurement of coherent ϕ -meson photoproduction from 4He near threshold
NASA Astrophysics Data System (ADS)
Hiraiwa, T.; Yosoi, M.; Niiyama, M.; Morino, Y.; Nakatsugawa, Y.; Sumihama, M.; Ahn, D. S.; Ahn, J. K.; Chang, W. C.; Chen, J. Y.; Daté, S.; Fujimura, H.; Fukui, S.; Hicks, K.; Hotta, T.; Hwang, S. H.; Ishikawa, T.; Kato, Y.; Kawai, H.; Kohri, H.; Kon, Y.; Lin, P. J.; Maeda, Y.; Miyabe, M.; Mizutani, K.; Muramatsu, N.; Nakano, T.; Nozawa, Y.; Ohashi, Y.; Ohta, T.; Oka, M.; Rangacharyulu, C.; Ryu, S. Y.; Saito, T.; Sawada, T.; Shimizu, H.; Strokovsky, E. A.; Sugaya, Y.; Suzuki, K.; Tokiyasu, A. O.; Tomioka, T.; Tsunemi, T.; Uchida, M.; Yorita, T.; LEPS Collaboration
2018-03-01
The differential cross sections and decay angular distributions for coherent ϕ -meson photoproduction from helium-4 are measured for the first time at forward angles with linearly polarized photons in the energy range Eγ=1.685 -2.385 GeV . Thanks to the target with spin-parity JP=0+ , unnatural-parity exchanges are absent, and thus natural-parity exchanges can be investigated clearly. The decay asymmetry with respect to photon polarization is shown to be very close to the maximal value. This ensures the strong dominance (>94 %) of natural-parity exchanges in this reaction. To evaluate the contribution from natural-parity exchanges to the forward cross section (θ =0∘ ) for the γ p →ϕ p reaction near threshold, the energy dependence of the forward cross section (θ =0∘ ) for the γ 4He →ϕ 4He reaction is analyzed. The comparison to γ p →ϕ p data suggests that enhancement of the forward cross section arising from natural-parity exchanges and/or destructive interference between natural-parity and unnatural-parity exchanges is needed in the γ p →ϕ p reaction near threshold.
Rotem, Avital; Henik, Avishai
2013-02-01
Parity helps us determine whether an arithmetic equation is true or false. The current research examines the development of sensitivity to parity cues in multiplication in typically achieving (TA) children (grades 2, 3, 4 and 6) and in children with mathematics learning disabilities (MLD, grades 6 and 8), via a verification task. In TA children the onset of parity sensitivity was observed at the beginning of 3rd grade, whereas in children with MLD it was documented only in 8th grade. These results suggest that children with MLD develop parity aspects of number sense, though later than TA children. To check the plausibility of equations, children used mainly the multiplication parity rule rather than familiarity with even products. Similar to observations in adults, parity sensitivity was largest for problems with two even operands, moderate for problems with one even and one odd operand, and smallest for problems with two odd operands. Copyright © 2012 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Liu, Tuo; Zhu, Xuefeng; Chen, Fei; Liang, Shanjun; Zhu, Jie
2018-03-01
Exploring the concept of non-Hermitian Hamiltonians respecting parity-time symmetry with classical wave systems is of great interest as it enables the experimental investigation of parity-time-symmetric systems through the quantum-classical analogue. Here, we demonstrate unidirectional wave vector manipulation in two-dimensional space, with an all passive acoustic parity-time-symmetric metamaterials crystal. The metamaterials crystal is constructed through interleaving groove- and holey-structured acoustic metamaterials to provide an intrinsic parity-time-symmetric potential that is two-dimensionally extended and curved, which allows the flexible manipulation of unpaired wave vectors. At the transition point from the unbroken to broken parity-time symmetry phase, the unidirectional sound focusing effect (along with reflectionless acoustic transparency in the opposite direction) is experimentally realized over the spectrum. This demonstration confirms the capability of passive acoustic systems to carry the experimental studies on general parity-time symmetry physics and further reveals the unique functionalities enabled by the judiciously tailored unidirectional wave vectors in space.
Taste symmetry breaking with hypercubic-smeared staggered fermions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bae, Taegil; Adams, David H.; Kim, Hyung-Jin
2008-05-01
We study the impact of hypercubic (HYP) smearing on the size of taste-breaking for staggered fermions, comparing to unimproved and to asqtad-improved staggered fermions. As in previous studies, we find a substantial reduction in taste-breaking compared to unimproved staggered fermions (by a factor of 4-7 on lattices with spacing a{approx_equal}0.1 fm). In addition, we observe that discretization effects of next-to-leading order in the chiral expansion (O(a{sup 2}p{sup 2})) are markedly reduced by HYP smearing. Compared to asqtad valence fermions, we find that taste-breaking in the pion spectrum is reduced by a factor of 2.5-3, down to a level comparable tomore » the expected size of generic O(a{sup 2}) effects. Our results suggest that, once one reaches a lattice spacing of a{approx_equal}0.09 fm, taste-breaking will be small enough after HYP smearing that one can use a modified power counting in which O(a{sup 2})<
Fermion-number violation in regularizations that preserve fermion-number symmetry
NASA Astrophysics Data System (ADS)
Golterman, Maarten; Shamir, Yigal
2003-01-01
There exist both continuum and lattice regularizations of gauge theories with fermions which preserve chiral U(1) invariance (“fermion number”). Such regularizations necessarily break gauge invariance but, in a covariant gauge, one recovers gauge invariance to all orders in perturbation theory by including suitable counterterms. At the nonperturbative level, an apparent conflict then arises between the chiral U(1) symmetry of the regularized theory and the existence of ’t Hooft vertices in the renormalized theory. The only possible resolution of the paradox is that the chiral U(1) symmetry is broken spontaneously in the enlarged Hilbert space of the covariantly gauge-fixed theory. The corresponding Goldstone pole is unphysical. The theory must therefore be defined by introducing a small fermion-mass term that breaks explicitly the chiral U(1) invariance and is sent to zero after the infinite-volume limit has been taken. Using this careful definition (and a lattice regularization) for the calculation of correlation functions in the one-instanton sector, we show that the ’t Hooft vertices are recovered as expected.
Bravyi-Kitaev Superfast simulation of electronic structure on a quantum computer.
Setia, Kanav; Whitfield, James D
2018-04-28
Present quantum computers often work with distinguishable qubits as their computational units. In order to simulate indistinguishable fermionic particles, it is first required to map the fermionic state to the state of the qubits. The Bravyi-Kitaev Superfast (BKSF) algorithm can be used to accomplish this mapping. The BKSF mapping has connections to quantum error correction and opens the door to new ways of understanding fermionic simulation in a topological context. Here, we present the first detailed exposition of the BKSF algorithm for molecular simulation. We provide the BKSF transformed qubit operators and report on our implementation of the BKSF fermion-to-qubits transform in OpenFermion. In this initial study of a hydrogen molecule we have compared BKSF, Jordan-Wigner, and Bravyi-Kitaev transforms under the Trotter approximation. The gate count to implement BKSF is lower than Jordan-Wigner but higher than Bravyi-Kitaev. We considered different orderings of the exponentiated terms and found lower Trotter errors than the previously reported for Jordan-Wigner and Bravyi-Kitaev algorithms. These results open the door to the further study of the BKSF algorithm for quantum simulation.
Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions.
Weng, Z F; Smidman, M; Jiao, L; Lu, Xin; Yuan, H Q
2016-09-01
Heavy fermions have served as prototype examples of strongly-correlated electron systems. The occurrence of unconventional superconductivity in close proximity to the electronic instabilities associated with various degrees of freedom points to an intricate relationship between superconductivity and other electronic states, which is unique but also shares some common features with high temperature superconductivity. The magnetic order in heavy fermion compounds can be continuously suppressed by tuning external parameters to a quantum critical point, and the role of quantum criticality in determining the properties of heavy fermion systems is an important unresolved issue. Here we review the recent progress of studies on Ce based heavy fermion superconductors, with an emphasis on the superconductivity emerging on the edge of magnetic and charge instabilities as well as the quantum phase transitions which occur by tuning different parameters, such as pressure, magnetic field and doping. We discuss systems where multiple quantum critical points occur and whether they can be classified in a unified manner, in particular in terms of the evolution of the Fermi surface topology.
Destruction of the Kondo effect in the cubic heavy-fermion compound Ce3Pd20Si6
NASA Astrophysics Data System (ADS)
Custers, J.; Lorenzer, K.-A.; Müller, M.; Prokofiev, A.; Sidorenko, A.; Winkler, H.; Strydom, A. M.; Shimura, Y.; Sakakibara, T.; Yu, R.; Si, Q.; Paschen, S.
2012-03-01
How ground states of quantum matter transform between one another reveals deep insights into the mechanisms stabilizing them. Correspondingly, quantum phase transitions are explored in numerous materials classes, with heavy-fermion compounds being among the most prominent ones. Recent studies in an anisotropic heavy-fermion compound have shown that different types of transitions are induced by variations of chemical or external pressure, raising the question of the extent to which heavy-fermion quantum criticality is universal. To make progress, it is essential to broaden both the materials basis and the microscopic parameter variety. Here, we identify a cubic heavy-fermion material as exhibiting a field-induced quantum phase transition, and show how the material can be used to explore one extreme of the dimensionality axis. The transition between two different ordered phases is accompanied by an abrupt change of Fermi surface, reminiscent of what happens across the field-induced antiferromagnetic to paramagnetic transition in the anisotropic YbRh2Si2. This finding leads to a materials-based global phase diagram—a precondition for a unified theoretical description.
Scattering of fermions in the Yukawa theory coupled to unimodular gravity
NASA Astrophysics Data System (ADS)
Gonzalez-Martin, S.; Martin, C. P.
2018-03-01
We compute the lowest order gravitational UV divergent radiative corrections to the S matrix element of the fermion + fermion→ fermion + fermion scattering process in the massive Yukawa theory, coupled either to Unimodular Gravity or to General Relativity. We show that both Unimodular Gravity and General Relativity give rise to the same UV divergent contribution in Dimensional Regularization. This is a nontrivial result, since in the classical action of Unimodular Gravity coupled to the Yukawa theory, the graviton field does not couple neither to the mass operator nor to the Yukawa operator. This is unlike the General Relativity case. The agreement found points in the direction that Unimodular Gravity and General Relativity give rise to the same quantum theory when coupled to matter, as long as the Cosmological Constant vanishes. Along the way we have come across another unexpected cancellation of UV divergences for both Unimodular Gravity and General Relativity, resulting in the UV finiteness of the one-loop and κ y^2 order of the vertex involving two fermions and one graviton only.
Interplay between magnetism and relativistic fermions in Eu doped (Sr/Ba)MnSb2
NASA Astrophysics Data System (ADS)
Liu, Jinyu; Hu, Jin; Zhu, Yanglin; Chuang, Alyssa; Graf, David; Jaime, Marcelo; Balakirev, Fedor; Weickert, Franziska; Zhang, Qiang; Ditusa, John; Wu, Yan; Cao, Huibo; Mao, Zhiqiang
Layered compounds AMnBi2 (A =Ca, Sr, Ba, Eu, and Yb) have been established as Dirac materials with fascinating properties. In our previous work, we have demonstrated that Sr1-y Mn1-z Sb2 (y, z <0.1), isostructural to AMnBi2, not only host relativistic fermions, but also exhibit ferromagnetic properties, with its ferromagnetism being coupled to the relativistic fermions' transport. To gain further insight into the relativistic fermion-magnetism coupling, we have synthesized a series of Eu doped (Sr/Ba)MnSb2 single crystals and found Eu moments order antiferromagnetically. Through neutron scattering experiments, we determined the magnetic structures for Sr1-xEuxMnSb2 with x = 0.2, 0.5, and 0.8. From magnetotransport measurements, we find the Eu antiferromagnetism is also coupled to relativistic fermion transport. More importantly, we observed a novel quantum phase with saturated magnetoresistivity near the quantum limit for the 10% Eu doped BaMnSb2 sample. We will discuss possible mechanisms for this novel phase.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jain, Jainendra
2011-07-15
The fractional quantum Hall effect (FQHE) is one of the most amazing collective states discovered in modern times. A remarkably detailed and accurate understanding of its nonperturbative physics has been achieved in terms of a new class of exotic particles called composite fermions. I will begin with a brief review of the composite fermion theory and its outstanding successes. The rest of the talk will be concerned with fractional quantum Hall effect in graphene, observed recently. I will present results of theoretical studies that demonstrate that composite fermions are formed in graphene as well, but the spin and valley degeneraciesmore » and the linear dispersion of electrons produce interesting new physics relative to that in the usual two-dimensional GaAs systems. Composite fermion theory allows detailed predictions about FQHE in graphene in regimes when either or both of the spin and valley degeneracies are broken. I will discuss the relevance of our theory to recent experiments. This work on FQHE in graphene has been performed in collaboration with Csaba Toke.« less
Fermion-induced quantum critical points in two-dimensional Dirac semimetals
NASA Astrophysics Data System (ADS)
Jian, Shao-Kai; Yao, Hong
2017-11-01
In this paper we investigate the nature of quantum phase transitions between two-dimensional Dirac semimetals and Z3-ordered phases (e.g., Kekule valence-bond solid), where cubic terms of the order parameter are allowed in the quantum Landau-Ginzberg theory and the transitions are putatively first order. From large-N renormalization-group (RG) analysis, we find that fermion-induced quantum critical points (FIQCPs) [Z.-X. Li et al., Nat. Commun. 8, 314 (2017), 10.1038/s41467-017-00167-6] occur when N (the number of flavors of four-component Dirac fermions) is larger than a critical value Nc. Remarkably, from the knowledge of space-time supersymmetry, we obtain an exact lower bound for Nc, i.e., Nc>1 /2 . (Here the "1/2" flavor of four-component Dirac fermions is equivalent to one flavor of four-component Majorana fermions). Moreover, we show that the emergence of two length scales is a typical phenomenon of FIQCPs and obtain two different critical exponents, i.e., ν ≠ν' , by large-N RG calculations. We further give a brief discussion of possible experimental realizations of FIQCPs.
NASA Astrophysics Data System (ADS)
Sepehri, Alireza; Shoorvazi, Somayyeh
In this paper, we will consider the birth and evolution of fields during formation of N-dimensional manifolds from joining point-like ones. We will show that at the beginning, only there are point-like manifolds which some strings are attached to them. By joining these manifolds, 1-dimensional manifolds are appeared and gravity, fermion, and gauge fields are emerged. By coupling these manifolds, higher dimensional manifolds are produced and higher orders of fermion, gauge fields and gravity are emerged. By decaying N-dimensional manifold, two child manifolds and a Chern-Simons one are born and anomaly is emerged. The Chern-Simons manifold connects two child manifolds and leads to the energy transmission from the bulk to manifolds and their expansion. We show that F-gravity can be emerged during the formation of N-dimensional manifold from point-like manifolds. This type of F-gravity includes both type of fermionic and bosonic gravity. G-fields and also C-fields which are produced by fermionic strings produce extra energy and change the gravity.
Minimally doubled fermions and spontaneous chiral symmetry breaking
NASA Astrophysics Data System (ADS)
Osmanaj (Zeqirllari), Rudina; Hyka (Xhako), Dafina
2018-03-01
Chiral symmetry breaking in massless QCD is a very important feature in the current understanding of low energy physics. Low - lying Dirac modes are suitable to help us understand the spontaneous chiral symmetry breaking, since the formation of a non zero chiral condensate is an effect of their accumulation near zero. The Banks - Casher relation links the spectral density of the Dirac operator to the condensate with an identity that can be read in both directions. In this work we propose a spectral method to achieve a reliable determination of the density of eigenvalues of Dirac operator near zero using the Gauss - Lanczos quadrature. In order to understand better the dynamical chiral symmetry breaking and use the method we propose, we have chosen to work with minimally doubled fermions. These kind of fermions have been proposed as a strictly local discretization of the QCD fermions action, which preserves chiral symmetry at finite cut-off. Being chiral fermions, is easier to work with them and their low - lying Dirac modes and to understand the dynamical spontaneous chiral symmetry breaking.
Effective four-fermion operators in top physics: A roadmap
NASA Astrophysics Data System (ADS)
Aguilar-Saavedra, J. A.
2011-02-01
We write down a minimal basis for dimension-six gauge-invariant four-fermion operators, with some operator replacements with respect to previous ones which make it simpler for calculations. Using this basis we classify all four-fermion operator contributions involving one or two top quarks. Taking into account the different fermion chiralities, possible colour contractions and independent flavour combinations, a total number of 572 gauge-invariant operators are involved. We apply this to calculate all three-body top decay widths t→dud, t→dei+ν, t→uuu, t→uej+ei-, t→uνν (with i,j,k generation indices) mediated by dimension-six four-fermion operators, including the interference with the Standard Model amplitudes when present. All single top production cross sections in pp, pp¯ and ee collisions are calculated as well, namely ud→dt, dd→ut, ud→dt, uu→ut, uu→ut, ee→ut and the charge conjugate processes. We also compute all top pair production cross sections, uu→tt¯, dd→tt¯, uu→tt and ee→tt¯. Our results are completely general, without assuming any particular relation among effective operator coefficients.
Towards a complete A4 × SU(5) SUSY GUT
NASA Astrophysics Data System (ADS)
Björkeroth, Fredrik; de Anda, Francisco J.; de Medeiros Varzielas, Ivo; King, Stephen F.
2015-06-01
We propose a renormalisable model based on A 4 family symmetry with an SU(5) grand unified theory (GUT) which leads to the minimal supersymmetric standard model (MSSM) with a ℤ9 × ℤ6 symmetry provides the fermion mass hierarchy in both the quark and lepton sectors, while ℤ {4/ R } symmetry is broken to ℤ {2/ R }, identified as usual R-parity. Proton decay is highly sup-pressed by these symmetries. The strong CP problem is solved in a similar way to the Nelson-Barr mechanism. We discuss both the A 4 and SU(5) symmetry breaking sectors, including doublet-triplet splitting, Higgs mixing and the origin of the μ term. The model provides an excellent fit (better than one sigma) to all quark and lepton (including neu-trino) masses and mixing with spontaneous CP violation. With the A 4 vacuum alignments, (0, 1, 1) and (1, 3, 1), the model predicts the entire PMNS mixing matrix with no free pa-rameters, up to a relative phase, selected to be 2π/3 from a choice of the nine complex roots of unity, which is identified as the leptogenesis phase. The model predicts a normal neutrino mass hierarchy with leptonic angles θ{13/ ι } ≈ 8.7∘, θ{12/ ι } ≈ 34∘, θ{23/ ι } ≈ 46∘ and an oscillation phase δ ι ≈ - 87∘.
Peterson, Emma; Busch, Susan
2018-04-01
The Mental Health Parity and Addiction Equity Act (MHPAEA) of 2008 changed the landscape of mental health and substance use disorder coverage in the United States. The MHPAEA's comprehensiveness compared with past parity laws, including its extension of parity to plan management strategies, the so-called nonquantitative treatment limitations (NQTL), led to significant improvements in mental health care coverage. In this article, we review the history of this landmark legislation and its recent expansions to new populations, describe past research on the effects of this and other mental health/substance use disorder parity laws, and describe some directions for future research, including NQTL compliance issues, effects of parity on individuals with severe mental illness, and measurement of benefits other than mental health care use.
NASA Astrophysics Data System (ADS)
Mazzucchi, Gabriel; Kozlowski, Wojciech; Caballero-Benitez, Santiago F.; Elliott, Thomas J.; Mekhov, Igor B.
2016-02-01
Trapping ultracold atoms in optical lattices enabled numerous breakthroughs uniting several disciplines. Coupling these systems to quantized light leads to a plethora of new phenomena and has opened up a new field of study. Here we introduce an unusual additional source of competition in a many-body strongly correlated system: We prove that quantum backaction of global measurement is able to efficiently compete with intrinsic short-range dynamics of an atomic system. The competition becomes possible due to the ability to change the spatial profile of a global measurement at a microscopic scale comparable to the lattice period without the need of single site addressing. In coherence with a general physical concept, where new competitions typically lead to new phenomena, we demonstrate nontrivial dynamical effects such as large-scale multimode oscillations, long-range entanglement, and correlated tunneling, as well as selective suppression and enhancement of dynamical processes beyond the projective limit of the quantum Zeno effect. We demonstrate both the breakup and protection of strongly interacting fermion pairs by measurement. Such a quantum optical approach introduces into many-body physics novel processes, objects, and methods of quantum engineering, including the design of many-body entangled environments for open systems.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ma, Junzhang; Yi, Changjiang; Lv, Baiqing
Topological insulators (TIs) host novel states of quantum matter characterized by nontrivial conducting boundary states connecting valence and conduction bulk bands. All TIs discovered experimentally so far rely on either time-reversal or mirror crystal symmorphic symmetry to protect massless Dirac-like boundary states. Several materials were recently proposed to be TIs with nonsymmorphic symmetry, where a glide mirror protects exotic surface fermions with hourglass-shaped dispersion. However, an experimental confirmation of this new fermion is missing. Using angle-resolved photoemission spectroscopy, we provide experimental evidence of hourglass fermions on the (010) surface of crystalline KHgSb, whereas the (001) surface has no boundary state,more » in agreement with first-principles calculations. Our study will stimulate further research activities of topological properties of nonsymmorphic materials.« less
Scattering length of composite bosons in the three-dimensional BCS-BEC crossover
NASA Astrophysics Data System (ADS)
Salasnich, L.; Bighin, G.
2015-03-01
We study the zero-temperature grand potential of a three-dimensional superfluid made of ultracold fermionic alkali-metal atoms in the BCS-BEC crossover. In particular, we analyze the zero-point energy of both fermionic single-particle excitations and bosonic collective excitations. The bosonic elementary excitations, which are crucial to obtain a reliable equation of state in the Bose-Einstein condensate regime, are obtained with a low-momentum expansion up to the forth order of the quadratic (Gaussian) action of the fluctuating pairing field. By performing a cutoff regularization and renormalization of Gaussian fluctuations, we find that the scattering length aB of composite bosons, bound states of fermionic pairs, is given by aB=(2 /3 ) aF , where aF is the scattering length of fermions.
Ma, Junzhang; Yi, Changjiang; Lv, Baiqing; ...
2017-05-05
Topological insulators (TIs) host novel states of quantum matter characterized by nontrivial conducting boundary states connecting valence and conduction bulk bands. All TIs discovered experimentally so far rely on either time-reversal or mirror crystal symmorphic symmetry to protect massless Dirac-like boundary states. Several materials were recently proposed to be TIs with nonsymmorphic symmetry, where a glide mirror protects exotic surface fermions with hourglass-shaped dispersion. However, an experimental confirmation of this new fermion is missing. Using angle-resolved photoemission spectroscopy, we provide experimental evidence of hourglass fermions on the (010) surface of crystalline KHgSb, whereas the (001) surface has no boundary state,more » in agreement with first-principles calculations. Our study will stimulate further research activities of topological properties of nonsymmorphic materials.« less
Solution to the sign problem in a frustrated quantum impurity model
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hann, Connor T., E-mail: connor.hann@yale.edu; Huffman, Emilie; Chandrasekharan, Shailesh
2017-01-15
In this work we solve the sign problem of a frustrated quantum impurity model consisting of three quantum spin-half chains interacting through an anti-ferromagnetic Heisenberg interaction at one end. We first map the model into a repulsive Hubbard model of spin-half fermions hopping on three independent one dimensional chains that interact through a triangular hopping at one end. We then convert the fermion model into an inhomogeneous one dimensional model and express the partition function as a weighted sum over fermion worldline configurations. By imposing a pairing of fermion worldlines in half the space we show that all negative weightmore » configurations can be eliminated. This pairing naturally leads to the original frustrated quantum spin model at half filling and thus solves its sign problem.« less
Annihilation of singlet fermionic dark matter into two photons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ettefaghi, M.M.; Moazzemi, R., E-mail: mettefaghi@qom.ac.ir, E-mail: r.moazzemi@qom.ac.ir
2013-02-01
We consider an extension of the standard model in which a singlet fermionic particle, to serve as cold dark matter, and a singlet Higgs are added. We perform a reanalysis on the free parameters. In particular, demanding a correct relic abundance of dark matter, we derive and plot the coupling of the singlet fermion with the singlet Higgs, g{sub s}, versus the dark matter mass. We analytically compute the pair annihilation cross section of singlet fermionic dark matter into two photons. The thermally averaged of this cross section is calculated for wide range of energies and plotted versus dark mattermore » mass using g{sub s} consistent with the relic abundance condition. We also compare our results with the Fermi-Lat observations.« less
Dirac fermions in an antiferromagnetic semimetal
NASA Astrophysics Data System (ADS)
Tang, Peizhe; Zhou, Quan; Xu, Gang; Zhang, Shou-Cheng
2016-12-01
Analogues of the elementary particles have been extensively searched for in condensed-matter systems for both scientific interest and technological applications. Recently, massless Dirac fermions were found to emerge as low-energy excitations in materials now known as Dirac semimetals. All of the currently known Dirac semimetals are non-magnetic with both time-reversal symmetry and inversion symmetry . Here we show that Dirac fermions can exist in one type of antiferromagnetic system, where both and are broken but their combination is respected. We propose orthorhombic antiferromagnet CuMnAs as a candidate, analyse the robustness of the Dirac points under symmetry protections and demonstrate its distinctive bulk dispersions, as well as the corresponding surface states, by ab initio calculations. Our results provide a possible platform to study the interplay of Dirac fermion physics and magnetism.
Landau Levels of Majorana Fermions in a Spin Liquid.
Rachel, Stephan; Fritz, Lars; Vojta, Matthias
2016-04-22
Majorana fermions, originally proposed as elementary particles acting as their own antiparticles, can be realized in condensed-matter systems as emergent quasiparticles, a situation often accompanied by topological order. Here we propose a physical system which realizes Landau levels-highly degenerate single-particle states usually resulting from an orbital magnetic field acting on charged particles-for Majorana fermions. This is achieved in a variant of a quantum spin system due to Kitaev which is distorted by triaxial strain. This strained Kitaev model displays a spin-liquid phase with charge-neutral Majorana-fermion excitations whose spectrum corresponds to that of Landau levels, here arising from a tailored pseudomagnetic field. We show that measuring the dynamic spin susceptibility reveals the Landau-level structure by a remarkable mechanism of probe-induced bound-state formation.
Baryon spectrum of SU(4) composite Higgs theory with two distinct fermion representations
NASA Astrophysics Data System (ADS)
Ayyar, Venkitesh; DeGrand, Thomas; Hackett, Daniel C.; Jay, William I.; Neil, Ethan T.; Shamir, Yigal; Svetitsky, Benjamin
2018-06-01
We use lattice simulations to compute the baryon spectrum of SU(4) lattice gauge theory coupled to dynamical fermions in the fundamental and two-index antisymmetric (sextet) representations simultaneously. This model is closely related to a composite Higgs model in which the chimera baryon made up of fermions from both representations plays the role of a composite top-quark partner. The dependence of the baryon masses on each underlying fermion mass is found to be generally consistent with a quark-model description and large-Nc scaling. We combine our numerical results with experimental bounds on the scale of the new strong sector to estimate a lower bound on the mass of the top-quark partner. We discuss some theoretical uncertainties associated with this estimate.
Gravitationally bound BCS state as dark matter
DOE Office of Scientific and Technical Information (OSTI.GOV)
Alexander, Stephon; Cormack, Sam, E-mail: stephon_alexander@brown.edu, E-mail: samuel.c.cormack.gr@dartmouth.edu
2017-04-01
We explore the possibility that fermionic dark matter undergoes a BCS transition to form a superfluid. This requires an attractive interaction between fermions and we describe a possible source of this interaction induced by torsion. We describe the gravitating fermion system with the Bogoliubov-de Gennes formalism in the local density approximation. We solve the Poisson equation along with the equations for the density and gap energy of the fermions to find a self-gravitating, superfluid solution for dark matter halos. In order to produce halos the size of dwarf galaxies, we require a particle mass of ∼ 200 eV. We findmore » a maximum attractive coupling strength before the halo becomes unstable. If dark matter halos do have a superfluid component, this raises the possibility that they contain vortex lines.« less
Birefringent breakup of Dirac fermions on a square optical lattice
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kennett, Malcolm P.; Komeilizadeh, Nazanin; Kaveh, Kamran
2011-05-15
We introduce a lattice model for fermions in a spatially periodic magnetic field that also has spatially periodic hopping amplitudes. We discuss how this model might be realized with cold atoms in an artificial magnetic field on a square optical lattice. When there is an average flux of half a flux quantum per plaquette, the spectrum of low-energy excitations can be described by massless Dirac fermions in which the usually doubly degenerate Dirac cones split into cones with different ''speeds of light.'' These gapless birefringent Dirac fermions arise because of broken chiral symmetry in the kinetic energy term of themore » effective low-energy Hamiltonian. We characterize the effects of various perturbations to the low-energy spectrum, including staggered potentials, interactions, and domain-wall topological defects.« less
Quantum Monte Carlo Simulation of Frustrated Kondo Lattice Models
NASA Astrophysics Data System (ADS)
Sato, Toshihiro; Assaad, Fakher F.; Grover, Tarun
2018-03-01
The absence of the negative sign problem in quantum Monte Carlo simulations of spin and fermion systems has different origins. World-line based algorithms for spins require positivity of matrix elements whereas auxiliary field approaches for fermions depend on symmetries such as particle-hole symmetry. For negative-sign-free spin and fermionic systems, we show that one can formulate a negative-sign-free auxiliary field quantum Monte Carlo algorithm that allows Kondo coupling of fermions with the spins. Using this general approach, we study a half-filled Kondo lattice model on the honeycomb lattice with geometric frustration. In addition to the conventional Kondo insulator and antiferromagnetically ordered phases, we find a partial Kondo screened state where spins are selectively screened so as to alleviate frustration, and the lattice rotation symmetry is broken nematically.
Classification of symmetry-protected phases for interacting fermions in two dimensions
NASA Astrophysics Data System (ADS)
Cheng, Meng; Bi, Zhen; You, Yi-Zhuang; Gu, Zheng-Cheng
2018-05-01
Recently, it has been established that two-dimensional bosonic symmetry-protected topological (SPT) phases with on-site unitary symmetry G can be completely classified by the group cohomology H3( G ,U (1 ) ) . Later, group supercohomology was proposed as a partial classification for SPT phases of interacting fermions. In this work, we revisit this problem based on the algebraic theory of symmetry and defects in two-dimensional topological phases. We reproduce the partial classifications given by group supercohomology, and we also show that with an additional H1(G ,Z2) structure, a complete classification of SPT phases for two-dimensional interacting fermion systems with a total symmetry group G ×Z2f is obtained. We also discuss the classification of interacting fermionic SPT phases protected by time-reversal symmetry.
Adding gauge fields to Kaplan's fermions
NASA Astrophysics Data System (ADS)
Blum, T.; Kärkkäinen, Leo
1994-04-01
We experiment with adding dynamical gauge field to Kaplan (defect) fermions. In the case of U (1) gauge theory we use an inhomogenous Higgs mechanism to restrict the 3d gauge dynamics to a planar 2d defect. In our simulations the 3d theory produce the correct 2d gauge dynamics. We measure fermion propagators with dynamical gauge fields. They posses the correct chiral structure. The fermions at the boundary of the support of the gauge field (waveguide) are non-chiral, and have a mass two times heavier than the chiral modes. Moreover, these modes cannot be excited by a source at the defect; implying that they are dynamically decoupled. We have also checked that the anomaly relation is fullfilled for the case of a smooth external gauge field.
Heidari, Behzad; Heidari, Parnaz; Nourooddini, Haj Ghorban; Hajian-Tilaki, Karim Ollah
2013-01-01
To investigate the impact of multiple pregnancies on postmenopausal bone mineral density (BMD). BMD at the femoral neck (FN) and lumbar spine (LS) was measured by dual energy X-ray absorptiometry (DXA) method. Diagnosis of osteoporosis (OP) was confirmed by World Health Organization criteria. Women were stratified according to number of parity as < 3, 4-7, and > 7 parity groups as well as in age groups of < 65 and 65 in age groups of < 65 and > or = 65 years. BMD values and frequency of OP were compared across the groups according to age. Multiple logistic regression analysis with calculation of adjusted odds ratio (OR) was used for association. A total of 264 women with mean age of 63 +/- 8.7 and mean menopausal duration of 15.8 +/- 10.2 years were studied. LS-OP and FN-OP were observed in 28% and 58.3% of women, respectively. There were significant differences in BMD values across different parity groups at both sites of LS and FN (p = 0.011 and p = 0.036, respectively). Parity 4-7 (vs. < or = 3) increased BMD nonsignificantly, but > 7 significantly decreased LS-BMD and FN-BMD as compared with 0-7 parity (p = 0.006 and p = 0.009, respectively). Parity > 7 increased the risk of LS-OP by OR = 1.81 (95% CI 1.03-3.1, p = 0.037) and FN-OP by OR = 1.67 (95% CI 0.97-2.8, p = 0.063). In addition, women with high parity had lower BMD decline at LS and FN by age (> or = 65 vs. < 65 years) by 1.3% (p = 0.77) and -10.1% (p = 0.009) as compared with 0-7 parity group by -9.5% (p = 0.001) and -15% (p = 0.0001), respectively. Parity > 7 is associated with spinal trabecular bone loss in younger postmenopausal women as well as an osteoprotective effect against age-related bone loss, which counteracts the early negative effect. Therefore, parity should not be considered as a risk factor for postmenopausal osteoporosis.
Local Hamiltonian Monte Carlo study of the massive schwinger model, the decoupling of heavy flavours
NASA Astrophysics Data System (ADS)
Ranft, J.
1983-12-01
The massive Schwinger model with two flavours is studied using the local hamiltonian lattice Monte Carlo method. Chiral symmetry breaking is studied using the fermion condensate as order parameter. For a small ratio of the two fermion masses, degeneracy of the two flavours is found. For a large ratio of the masses, the heavy flavour decouples and the light fermion behaves like in the one flavour Schwinger model. On leave from Sektion Physik, Karl-Marx-Universität, Leipzig, GDR.
Fermions tunneling from the Horowitz-Strominger Dilaton black hole
NASA Astrophysics Data System (ADS)
Li, Qiang; Zeng, Xiaoxiong
2009-06-01
Based on the work of Kerner and Mann, fermions tunneling from the Horowitz-Strominger Dilaton black hole on the membrane is studied. Owing to the coupling among electromagnetic field, matter field and gravity field, the Dirac equation of charged particles is introduced, and according to that, the expected emission temperature is obtained. After the self-gravitational interaction is considered, it is found that the tunneling rate of fermions also satisfies the underlying Unitary theory as the case of scalar particles.
Global analysis of fermion mixing with exotics
NASA Technical Reports Server (NTRS)
Nardi, Enrico; Roulet, Esteban; Tommasini, Daniele
1991-01-01
The limits are analyzed on deviation of the lepton and quark weak-couplings from their standard model values in a general class of models where the known fermions are allowed to mix with new heavy particles with exotic SU(2) x U(1) quantum number assignments (left-handed singlets or right-handed doublets). These mixings appear in many extensions of the electroweak theory such as models with mirror fermions, E(sub 6) models, etc. The results update previous analyses and improve considerably the existing bounds.
Gapped fermionic spectrum from a domain wall in seven dimension
NASA Astrophysics Data System (ADS)
Mukhopadhyay, Subir; Rai, Nishal
2018-05-01
We obtain a domain wall solution in maximally gauged seven dimensional supergravity, which interpolates between two AdS spaces and spontaneously breaks a U (1) symmetry. We analyse frequency dependence of conductivity and find power law behaviour at low frequency. We consider certain fermions of supergravity in the background of this domain wall and compute holographic spectral function of the operators in the dual six dimensional theory. We find fermionic operators involving bosons with non-zero expectation value lead to gapped spectrum.
The Feynman-Vernon Influence Functional Approach in QED
NASA Astrophysics Data System (ADS)
Biryukov, Alexander; Shleenkov, Mark
2016-10-01
In the path integral approach we describe evolution of interacting electromagnetic and fermionic fields by the use of density matrix formalism. The equation for density matrix and transitions probability for fermionic field is obtained as average of electromagnetic field influence functional. We obtain a formula for electromagnetic field influence functional calculating for its various initial and final state. We derive electromagnetic field influence functional when its initial and final states are vacuum. We present Lagrangian for relativistic fermionic field under influence of electromagnetic field vacuum.
Coherent vs. incoherent pairing in 2D systems near magnetic instability
NASA Astrophysics Data System (ADS)
Abanov, Ar.; Chubukov, A. V.; Finkel'stein, A. M.
2001-05-01
We study the superconductivity in 2D fermionic systems near antiferromagnetic instability, assuming that the pairing is mediated by spin fluctuations. This pairing involves fully incoherent fermions and diffusive spin excitations. We show that the competition between fermionic incoherence and strong pairing interaction yields the pairing instability temperature Tins which increases and saturates as the magnetic correlation length ξ → ∞. We argue that in this quantum-critical regime the pairing problem is qualitatively different from the BCS one.
On bound-states of the Gross Neveu model with massive fundamental fermions
NASA Astrophysics Data System (ADS)
Frishman, Yitzhak; Sonnenschein, Jacob
2018-01-01
In the search for QFT's that admit boundstates, we reinvestigate the two dimensional Gross-Neveu model, but with massive fermions. By computing the self-energy for the auxiliary boundstate field and the effective potential, we show that there are no bound states around the lowest minimum, but there is a meta-stable bound state around the other minimum, a local one. The latter decays by tunneling. We determine the dependence of its lifetime on the fermion mass and coupling constant.
NASA Astrophysics Data System (ADS)
Moessner, Roderich
Condensed matter systems provide emergent mini-universes in which quasiparticles may exist which do not correspond to any experimentally detected elementary particle. Topological quantum materials have been particularly productive in this regard, with the present search focussing on Majorana fermions, known theoretically already for decades. Here, we discuss manifestations of magnetic Majorana fermions in the Kitaev model. We place particular emphasis on their fate when perturbations, such as Heisenberg terms, are added to the ideal model system, and address experimental signatures of their vestiges in phases adjacent to the spin liquid.
Entanglement of Dirac fields in an expanding spacetime
NASA Astrophysics Data System (ADS)
Fuentes, Ivette; Mann, Robert B.; Martín-Martínez, Eduardo; Moradi, Shahpoor
2010-08-01
We study the entanglement generated between Dirac modes in a 2-dimensional conformally flat Robertson-Walker universe. We find radical qualitative differences between the bosonic and fermionic entanglement generated by the expansion. The particular way in which fermionic fields get entangled encodes more information about the underlying spacetime than the bosonic case, thereby allowing us to reconstruct the parameters of the history of the expansion. This highlights the importance of bosonic/fermionic statistics to account for relativistic effects on the entanglement of quantum fields.
Magnetotransport study of Dirac fermions in YbMnBi 2 antiferromagnet
Wang, Aifeng; Zaliznyak, I.; Ren, Weijun; ...
2016-10-15
We report quantum transport and Dirac fermions in YbMnBi 2 single crystals. YbMnBi 2 is a layered material with anisotropic conductivity and magnetic order below 290 K. Magnetotransport properties, nonzero Berry phase, and small cyclotron mass indicate the presence of Dirac fermions. Lastly, angular-dependent magnetoresistance indicates a possible quasi-two-dimensional Fermi surface, whereas the deviation from the nontrivial Berry phase expected for Dirac states suggests the contribution of parabolic bands at the Fermi level or spin-orbit coupling.
Is the Luttinger Liquid a New State of Matter?
NASA Astrophysics Data System (ADS)
Afonin, V. V.; Petrov, V. Y.
2010-02-01
We are demonstrating that the Luttinger model with short range interaction can be treated as a type of Fermi liquid. In line with the main dogma of Landau’s theory one can define a fermion excitation renormalized by interaction and show that in terms of these fermions any excited state of the system is described by free particles. The fermions are a mixture of renormalized right and left electrons. The electric charge and chirality of the Landau quasi-particle is discussed.
NASA Astrophysics Data System (ADS)
Siddiqui, Jawad M.
Grid parity for alternative energy resources occurs when the cost of electricity generated from the source is lower than or equal to the purchasing price of power from the electricity grid. This thesis aims to quantitatively analyze the evolution of hybrid stand-alone microgrids in the US, Germany, Pakistan and South Africa to determine grid parity for a solar PV/Diesel/Battery hybrid system. The Energy System Model (ESM) and NREL's Hybrid Optimization of Multiple Energy Resources (HOMER) software are used to simulate the microgrid operation and determine a Levelized Cost of Electricity (LCOE) figure for each location. This cost per kWh is then compared with two distinct estimates of future retail electricity prices at each location to determine grid parity points. Analysis results reveal that future estimates of LCOE for such hybrid stand-alone microgrids range within the 35-55 cents/kWh over the 25 year study period. Grid parity occurs earlier in locations with higher power prices or unreliable grids. For Pakistan grid parity is already here, while Germany hits parity between the years 2023-2029. Results for South Africa suggest a parity time range of the years 2040-2045. In the US, places with low grid prices do not hit parity during the study period. Sensitivity analysis results reveal the significant impact of financing and the cost of capital on these grid parity points, particularly in developing markets of Pakistan and South Africa. Overall, the study helps conclude that variations in energy markets may determine the fate of emerging energy technologies like microgrids. However, policy interventions have a significant impact on the final outcome, such as the grid parity in this case. Measures such as eliminating uncertainty in policies and improving financing can help these grids overcome barriers in developing economies, where they may find a greater use much earlier in time.
Implementation of mental health parity: lessons from california.
Rosenbach, Margo L; Lake, Timothy K; Williams, Susan R; Buck, Jeffrey A
2009-12-01
This article reports the experiences of health plans, providers, and consumers with California's mental health parity law and discusses implications for implementation of the 2008 federal parity law. This study used a multimodal data collection approach to assess the first five years of California's parity implementation (from 2000 to 2005). Telephone interviews were conducted with 68 state-level stakeholders, and in-person interviews were conducted with 77 community-based stakeholders. Six focus groups included 52 providers, and six included 32 consumers. A semistructured interview protocol was used. Interview notes and transcripts were coded to facilitate analysis. Health plans eliminated differential benefit limits and cost-sharing requirements for certain mental disorders to comply with the law, and they used managed care to control costs. In response to concerns about access to and quality of care, the state expanded oversight of health plans, issuing access-to-care regulations and conducting focused studies. California's parity law applied to a limited list of psychiatric diagnoses. Health plan executives said they spent considerable resources clarifying which diagnoses were covered at parity levels and concluded that the limited diagnosis list was unnecessary with managed care. Providers indicated that the diagnosis list had unintended consequences, including incentives to assign a more severe diagnosis that would be covered at parity levels, rather than a less severe diagnosis that would not be covered at such levels. The lack of consumer knowledge about parity was widely acknowledged, and consumers in the focus groups requested additional information about parity. Experiences in California suggest that implementation of the 2008 federal parity law should include monitoring health plan performance related to access and quality, in addition to monitoring coverage and costs; examining the breadth of diagnoses covered by health plans; and mounting a campaign to educate consumers about their insurance benefits.
Probing Novel Properties of Nucleons and Nuclei via Parity Violating Electron Scattering
DOE Office of Scientific and Technical Information (OSTI.GOV)
Mercado, Luis
2012-05-01
This thesis reports on two experiments conducted by the HAPPEx (Hall A Proton Parity Experiment) collaboration at the Thomas Jefferson National Accelerator Facility. For both, the weak neutral current interaction (WNC, mediated by the Z 0 boson) is used to probe novel properties of hadronic targets. The WNC interaction amplitude is extracted by measuring the parity-violating asymmetry in the elastic scattering of longitudinally polarized electrons o unpolarized target hadrons. HAPPEx-III, conducted in the Fall of 2009, used a liquid hydrogen target at a momentum transfer of Q 2 = 0.62 GeV 2. The measured asymmetry was used to set newmore » constraints on the contribution of strange quark form factors (G s E,M ) to the nucleon electromagnetic form factors. A value of A PV = -23.803±} 0.778 (stat)± 0.359 (syst) ppm resulted in G s E + 0.517G s M = 0.003± 0.010 (stat)± 0.004 (syst)± 0.009 (FF). PREx, conducted in the Spring of 2010, used a polarized electron beam on a 208Pb target at a momentum transfer of Q 2 = 0.009 GeV 2. This parity-violating asymmetry can be used to obtain a clean measurement of the root-mean-square radius of the neutrons in the 208Pb nucleus. The Z 0 boson couples mainly to neutrons; the neutron weak charge is much larger than that of the proton. The value of this asymmetry is at the sub-ppm level and has a projected experimental fractional precision of 3%. We will describe the accelerator setup used to set controls on helicity-correlated beam asymmetries and the analysis methods for finding the raw asymmetry for HAPPEx-III. We will also discuss in some detail the preparations to meet the experimental challenges associated with measuring such a small asymmetry with the degree of precision required for PREx.« less
Kim, Jin Soo; Yang, Xiaojian; Baidoo, Samuel Kofi
2016-01-01
The present study investigated the impact of parity 1 gilt body weight during late gestation (d 109) on subsequent reproductive performance of sows and performance of suckling pigs. A total of 2,404 farrowing records over 6 parities were divided into six groups on the basis of body weight (190, 200, 210, 220, 230, and 240 kg) at d 109 of gestation of 585 gilts. Significant effects (p< 0.05) of body weight on sow retention rate was noticed, with the 210 kg group having the lowest culling rate and highest total number of piglets born alive over the 6 parities. With increase of body weight, a linear increase (p<0.05) in losses of body weight and backfat during the lactation period of parity 1 and a linear decrease (p<0.05) in backfat loss for parities 4 and 6 were found. Compared with light sows, heavy sows had higher (p<0.05) litter weight at birth for parities 1 and 2 and at weaning in parity 1. Sow weaning-to-estrus interval of sows was not influenced (p>0.05) by body weight. In conclusion, maintaining optimal body weight during gestation would be beneficial to sows and suckling piglets. PMID:26954198
Phenomenology of the littlest Higgs model with T-parity
NASA Astrophysics Data System (ADS)
Hubisz, Jay; Meade, Patrick
2005-02-01
Little Higgs models offer an interesting approach to weakly coupled electroweak symmetry breaking without fine-tuning. The original little Higgs models were plagued by strong constraints from electroweak precision data which required a fine-tuning to be reintroduced. An economical solution to this problem is to introduce a discrete symmetry (analogous to R-parity of SUSY) called T-parity. T-parity not only eliminates most constraints from electroweak precision data, but it also leads to a promising dark matter candidate. In this paper we investigate the dark matter candidate in the littlest Higgs model with T-parity. An upper bound on the symmetry breaking scale f≲1.8 TeV naturally arises from calculating the relic density. We begin the study of the LHC phenomenology of the littlest Higgs model with T-parity. We find that the model offers an interesting collider signature that has a generic missing energy signal which could “fake” SUSY at the LHC. We also investigate the properties of the heavy partner of the top quark which is common to all littlest Higgs models, and how its properties are modified with the introduction of T-parity. We include an appendix with a list of Feynman rules specific to the littlest Higgs with T-parity to facilitate further study.
A high-performance Fortran code to calculate spin- and parity-dependent nuclear level densities
NASA Astrophysics Data System (ADS)
Sen'kov, R. A.; Horoi, M.; Zelevinsky, V. G.
2013-01-01
A high-performance Fortran code is developed to calculate the spin- and parity-dependent shell model nuclear level densities. The algorithm is based on the extension of methods of statistical spectroscopy and implies exact calculation of the first and second Hamiltonian moments for different configurations at fixed spin and parity. The proton-neutron formalism is used. We have applied the method for calculating the level densities for a set of nuclei in the sd-, pf-, and pf+g- model spaces. Examples of the calculations for 28Si (in the sd-model space) and 64Ge (in the pf+g-model space) are presented. To illustrate the power of the method we estimate the ground state energy of 64Ge in the larger model space pf+g, which is not accessible to direct shell model diagonalization due to the prohibitively large dimension, by comparing with the nuclear level densities at low excitation energy calculated in the smaller model space pf. Program summaryProgram title: MM Catalogue identifier: AENM_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENM_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 193181 No. of bytes in distributed program, including test data, etc.: 1298585 Distribution format: tar.gz Programming language: Fortran 90, MPI. Computer: Any architecture with a Fortran 90 compiler and MPI. Operating system: Linux. RAM: Proportional to the system size, in our examples, up to 75Mb Classification: 17.15. External routines: MPICH2 (http://www.mcs.anl.gov/research/projects/mpich2/) Nature of problem: Calculating of the spin- and parity-dependent nuclear level density. Solution method: The algorithm implies exact calculation of the first and second Hamiltonian moments for different configurations at fixed spin and parity. The code is parallelized using the Message Passing Interface and a master-slaves dynamical load-balancing approach. Restrictions: The program uses two-body interaction in a restricted single-level basis. For example, GXPF1A in the pf-valence space. Running time: Depends on the system size and the number of processors used (from 1 min to several hours).
Two- and Three-Dimensional Probes of Parity in Primordial Gravity Waves.
Masui, Kiyoshi Wesley; Pen, Ue-Li; Turok, Neil
2017-06-02
We show that three-dimensional information is critical to discerning the effects of parity violation in the primordial gravity-wave background. If present, helical gravity waves induce parity-violating correlations in the cosmic microwave background (CMB) between parity-odd polarization B modes and parity-even temperature anisotropies (T) or polarization E modes. Unfortunately, EB correlations are much weaker than would be naively expected, which we show is due to an approximate symmetry resulting from the two-dimensional nature of the CMB. The detectability of parity-violating correlations is exacerbated by the fact that the handedness of individual modes cannot be discerned in the two-dimensional CMB, leading to a noise contribution from scalar matter perturbations. In contrast, the tidal imprints of primordial gravity waves fossilized into the large-scale structure of the Universe are a three-dimensional probe of parity violation. Using such fossils the handedness of gravity waves may be determined on a mode-by-mode basis, permitting future surveys to probe helicity at the percent level if the amplitude of primordial gravity waves is near current observational upper limits.
Parity and the medicalization of addiction treatment.
Roy, Ken; Miller, Michael
2010-06-01
Parity, the idea that insurance coverage for the treatment of addiction should be on a par with insurance coverage for the treatment of other medical illnesses, is not a new idea, but the path to achieving "real parity" has been a long, hard and complex journey. Action by Congress to pass major parity legislation in 2008 was a huge step forward, but does not mean that parity has been achieved. Parity has required a paradigm shift in the understanding of addiction as a biological illness: many developments of science and policy changes by professional organizations and governmental entities have contributed to that paradigm shift. Access to adequate treatment for patients must acknowledge the paradigm shift reflected in parity as it has evolved to the current point: that this biological illness is widespread, that it is important that it be treated effectively, that appropriate third party payment for physician-provided or physician-supervised addiction treatment is critical for addiction medicine to become a part of the mainstream of our nation's healthcare delivery system, and that medical specialty care provides the most effective and cost effective benefit to patients and therefore to our society.
The realization of Majorana fermions in Kitaev Quantum Spin Lattice
NASA Astrophysics Data System (ADS)
Do, Seung-Hwan; Park, Sang-Youn; Yoshitake, Junki; Nasu, Joji; Motome, Yukitoshi; Kwon, Y. S.; Adroja, D. T.; Voneshen, D.; Park, J.-H.; Choi, Kwang-Yong; Ji, Sungdae
The Kitaev honeycomb lattice is envisioned as an ideal host for Majorana fermions that are created out of the spin liquid background. Combining specific heat and neutron scattering experiments with theoretical calculations, here, we establish a hitherto unparalleled spin fractionalization to two species of Majorana fermions in the Kitaev material α-RuCl3. The specific heat data unveil a two-stage release of magnetic entropy by (R/2)ln2 and the T-linear dependence at intermediate temperatures. Our inelastic neutron scattering measurements further corroborate two distinct characters of fractionalized excitations: an Y-like, dispersive, magnetic continuum at higher energies and a dispersionless excitation at low energies around the Brillouin zone center. These dual features are well described by a Ferromagnetic Kitaev model, providing a smoking gun proof of the itinerant and localized Majorana fermions emergent in Kitaev magnets.
Proposal to probe quantum nonlocality of Majorana fermions in tunneling experiments
NASA Astrophysics Data System (ADS)
Sau, Jay D.; Swingle, Brian; Tewari, Sumanta
2015-07-01
Topological Majorana fermion (MF) quasiparticles have been recently suggested to exist in semiconductor quantum wires with proximity induced superconductivity and a Zeeman field. Although the experimentally observed zero bias tunneling peak and a fractional ac-Josephson effect can be taken as necessary signatures of MFs, neither of them constitutes a sufficient "smoking gun" experiment. Since one pair of Majorana fermions share a single conventional fermionic degree of freedom, MFs are in a sense fractionalized excitations. Based on this fractionalization we propose a tunneling experiment that furnishes a nearly unique signature of end state MFs in semiconductor quantum wires. In particular, we show that a "teleportation"-like experiment is not enough to distinguish MFs from pairs of MFs, which are equivalent to conventional zero energy states, but our proposed tunneling experiment, in principle, can make this distinction.
High-order Path Integral Monte Carlo methods for solving strongly correlated fermion problems
NASA Astrophysics Data System (ADS)
Chin, Siu A.
2015-03-01
In solving for the ground state of a strongly correlated many-fermion system, the conventional second-order Path Integral Monte Carlo method is plagued with the sign problem. This is due to the large number of anti-symmetric free fermion propagators that are needed to extract the square of the ground state wave function at large imaginary time. In this work, I show that optimized fourth-order Path Integral Monte Carlo methods, which uses no more than 5 free-fermion propagators, in conjunction with the use of the Hamiltonian energy estimator, can yield accurate ground state energies for quantum dots with up to 20 polarized electrons. The correlations are directly built-in and no explicit wave functions are needed. This work is supported by the Qatar National Research Fund NPRP GRANT #5-674-1-114.
Particle statistics and lossy dynamics of ultracold atoms in optical lattices
NASA Astrophysics Data System (ADS)
Yago Malo, J.; van Nieuwenburg, E. P. L.; Fischer, M. H.; Daley, A. J.
2018-05-01
Experimental control over ultracold quantum gases has made it possible to investigate low-dimensional systems of both bosonic and fermionic atoms. In closed one-dimensional systems there are many similarities in the dynamics of local quantities for spinless fermions and strongly interacting "hard-core" bosons, which on a lattice can be formalized via a Jordan-Wigner transformation. In this study, we analyze the similarities and differences for spinless fermions and hard-core bosons on a lattice in the presence of particle loss. The removal of a single fermion causes differences in local quantities compared with the bosonic case because of the different particle exchange symmetry in the two cases. We identify deterministic and probabilistic signatures of these dynamics in terms of local particle density, which could be measured in ongoing experiments with quantum gas microscopes.
Realizing universal Majorana fermionic quantum computation
NASA Astrophysics Data System (ADS)
Wu, Ya-Jie; He, Jing; Kou, Su-Peng
2014-08-01
Majorana fermionic quantum computation (MFQC) was proposed by S. B. Bravyi and A. Yu. Kitaev [Ann. Phys. (NY) 298, 210 (2002), 10.1006/aphy.2002.6254], who indicated that a (nontopological) fault-tolerant quantum computer built from Majorana fermions may be more efficient than that built from distinguishable two-state systems. However, until now scientists have not known how to realize a MFQC in a physical system. In this paper we propose a possible realization of MFQC. We find that the end of a line defect of a p-wave superconductor or superfluid in a honeycomb lattice traps a Majorana zero mode, which becomes the starting point of MFQC. Then we show how to manipulate Majorana fermions to perform universal MFQC, which possesses possibilities for high-level local controllability through individually addressing the quantum states of individual constituent elements by using timely cold-atom technology.
Dirac fermions in an antiferromagnetic semimetal
Tang, Peizhe; Zhou, Quan; Xu, Gang; ...
2016-08-08
Analogues of the elementary particles have been extensively searched for in condensed-matter systems for both scientific interest and technological applications. Recently, massless Dirac fermions were found to emerge as low-energy excitations in materials now known as Dirac semimetals. All of the currently known Dirac semimetals are non-magnetic with both time-reversal symmetry and inversion symmetry. Here in this paper, we show that Dirac fermions can exist in one type of antiferromagnetic system, where both and are broken but their combination is respected. We propose orthorhombic antiferromagnet CuMnAs as a candidate, analyse the robustness of the Dirac points under symmetry protections andmore » demonstrate its distinctive bulk dispersions, as well as the corresponding surface states, by ab initio calculations. Our results provide a possible platform to study the interplay of Dirac fermion physics and magnetism.« less
Optical Selection Rule of Excitons in Gapped Chiral Fermion Systems
NASA Astrophysics Data System (ADS)
Zhang, Xiaoou; Shan, Wen-Yu; Xiao, Di
2018-02-01
We show that the exciton optical selection rule in gapped chiral fermion systems is governed by their winding number w , a topological quantity of the Bloch bands. Specifically, in a CN-invariant chiral fermion system, the angular momentum of bright exciton states is given by w ±1 +n N with n being an integer. We demonstrate our theory by proposing two chiral fermion systems capable of hosting dark s -like excitons: gapped surface states of a topological crystalline insulator with C4 rotational symmetry and biased 3 R -stacked MoS2 bilayers. In the latter case, we show that gating can be used to tune the s -like excitons from bright to dark by changing the winding number. Our theory thus provides a pathway to electrical control of optical transitions in two-dimensional material.
Role of quantum statistics in multi-particle decay dynamics
NASA Astrophysics Data System (ADS)
Marchewka, Avi; Granot, Er'el
2015-04-01
The role of quantum statistics in the decay dynamics of a multi-particle state, which is suddenly released from a confining potential, is investigated. For an initially confined double particle state, the exact dynamics is presented for both bosons and fermions. The time-evolution of the probability to measure two-particle is evaluated and some counterintuitive features are discussed. For instance, it is shown that although there is a higher chance of finding the two bosons (as oppose to fermions, and even distinguishable particles) at the initial trap region, there is a higher chance (higher than fermions) of finding them on two opposite sides of the trap as if the repulsion between bosons is higher than the repulsion between fermions. The results are demonstrated by numerical simulations and are calculated analytically in the short-time approximation. Furthermore, experimental validation is suggested.
Custodial isospin violation in the Lee-Wick standard model
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chivukula, R. Sekhar; Farzinnia, Arsham; Foadi, Roshan
2010-05-01
We analyze the tension between naturalness and isospin violation in the Lee-Wick standard model (LW SM) by computing tree-level and fermionic one-loop contributions to the post-LEP electroweak parameters (S-circumflex, T-circumflex, W, and Y) and the Zb{sub L}b-bar{sub L} coupling. The model is most natural when the LW partners of the gauge bosons and fermions are light, but small partner masses can lead to large isospin violation. The post-LEP parameters yield a simple picture in the LW SM: the gauge sector contributes to Y and W only, with leading contributions arising at tree level, while the fermion sector contributes to S-circumflexmore » and T-circumflex only, with leading corrections arising at one loop. Hence, W and Y constrain the masses of the LW gauge bosons to satisfy M{sub 1}, M{sub 2} > or approx. 2.4 TeV at 95% C.L. Likewise, experimental limits on T-circumflex reveal that the masses of the LW fermions must satisfy M{sub q}, M{sub t} > or approx. 1.6 TeV at 95% C.L. if the Higgs mass is light and tend to exclude the LW SM for any LW fermion masses if the Higgs mass is heavy. Contributions from the top-quark sector to the Zb{sub L}b{sub L} coupling can be even more stringent, placing a lower bound of 4 TeV on the LW fermion masses at 95% C.L.« less
Fermionic Spinon Theory of Square Lattice Spin Liquids near the Néel State
NASA Astrophysics Data System (ADS)
Thomson, Alex; Sachdev, Subir
2018-01-01
Quantum fluctuations of the Néel state of the square lattice antiferromagnet are usually described by a CP1 theory of bosonic spinons coupled to a U(1) gauge field, and with a global SU(2) spin rotation symmetry. Such a theory also has a confining phase with valence bond solid (VBS) order, and upon including spin-singlet charge-2 Higgs fields, deconfined phases with Z2 topological order possibly intertwined with discrete broken global symmetries. We present dual theories of the same phases starting from a mean-field theory of fermionic spinons moving in π flux in each square lattice plaquette. Fluctuations about this π -flux state are described by (2 +1 )-dimensional quantum chromodynamics (QCD3 ) with a SU(2) gauge group and Nf=2 flavors of massless Dirac fermions. It has recently been argued by Wang et al. [Deconfined Quantum Critical Points: Symmetries and Dualities, Phys. Rev. X 7, 031051 (2017)., 10.1103/PhysRevX.7.031051] that this QCD3 theory describes the Néel-VBS quantum phase transition. We introduce adjoint Higgs fields in QCD3 and obtain fermionic dual descriptions of the phases with Z2 topological order obtained earlier using the bosonic CP1 theory. We also present a fermionic spinon derivation of the monopole Berry phases in the U(1) gauge theory of the VBS state. The global phase diagram of these phases contains multicritical points, and our results imply new boson-fermion dualities between critical gauge theories of these points.
Quasi-stationary states and fermion pair creation from a vacuum in supercritical Coulomb field
NASA Astrophysics Data System (ADS)
Khalilov, V. R.
2017-12-01
Creation of charged fermion pair from a vacuum in so-called supercritical Coulomb potential is examined for the case when fermions can move only in the same (one) plane. In which case, quantum dynamics of charged massive or massless fermions can be described by the two-dimensional Dirac Hamiltonians with an usual (-a/r) Coulomb potential. These Hamiltonians are singular and require the additional definition in order for them to be treated as self-adjoint quantum-mechanical operators. We construct the self-adjoint two-dimensional Dirac Hamiltonians with a Coulomb potential and determine the quantum-mechanical states for such Hamiltonians in the corresponding Hilbert spaces of square-integrable functions. We determine the scattering amplitude in which the self-adjoint extension parameter is incorporated and then obtain equations implicitly defining possible discrete energy spectra of the self-adjoint Dirac Hamiltonians with a Coulomb potential. It is shown that this quantum system becomes unstable in the presence of a supercritical Coulomb potential which manifests in the appearance of quasi-stationary states in the lower (negative) energy continuum. The energy spectrum of those states is quasi-discrete, consists of broadened levels with widths related to the inverse lifetimes of the quasi-stationary states as well as the probability of creation of charged fermion pair by a supercritical Coulomb field. Explicit analytical expressions for the creation probabilities of charged (massive or massless) fermion pair are obtained in a supercritical Coulomb field.
Dong, Hang; Zhang, Wenyuan; Zhou, Li; Ma, Yongli
2015-01-01
We investigate the transition and damping of low-energy collective modes in a trapped unitary Fermi gas by solving the Boltzmann-Vlasov kinetic equation in a scaled form, which is combined with both the T-matrix fluctuation theory in normal phase and the mean-field theory in order phase. In order to connect the microscopic and kinetic descriptions of many-body Feshbach scattering, we adopt a phenomenological two-fluid physical approach, and derive the coupling constants in the order phase. By solving the Boltzmann-Vlasov steady-state equation in a variational form, we calculate two viscous relaxation rates with the collision probabilities of fermion’s scattering including fermions in the normal fluid and fermion pairs in the superfluid. Additionally, by considering the pairing and depairing of fermions, we get results of the frequency and damping of collective modes versus temperature and s-wave scattering length. Our theoretical results are in a remarkable agreement with the experimental data, particularly for the sharp transition between collisionless and hydrodynamic behaviour and strong damping between BCS and unitary limits near the phase transition. The sharp transition originates from the maximum of viscous relaxation rate caused by fermion-fermion pair collision at the phase transition point when the fermion depair, while the strong damping due to the fast varying of the frequency of collective modes from BCS limit to unitary limit. PMID:26522094
Domain wall fermion and CP symmetry breaking
NASA Astrophysics Data System (ADS)
Fujikawa, Kazuo; Suzuki, Hiroshi
2003-02-01
We examine the CP properties of chiral gauge theory defined by a formulation of the domain wall fermion, where the light field variables q and q¯ together with Pauli-Villars fields Q and Q¯ are utilized. It is shown that this domain wall representation in the infinite flavor limit N=∞ is valid only in the topologically trivial sector, and that the conflict among lattice chiral symmetry, strict locality and CP symmetry still persists for finite lattice spacing a. The CP transformation generally sends one representation of lattice chiral gauge theory into another representation of lattice chiral gauge theory, resulting in the inevitable change of propagators. A modified form of lattice CP transformation motivated by the domain wall fermion, which keeps the chiral action in terms of the Ginsparg-Wilson fermion invariant, is analyzed in detail; this provides an alternative way to understand the breaking of CP symmetry at least in the topologically trivial sector. We note that the conflict with CP symmetry could be regarded as a topological obstruction. We also discuss the issues related to the definition of Majorana fermions in connection with the supersymmetric Wess-Zumino model on the lattice.
Flavorful Z‧ signatures at LHC and ILC
NASA Astrophysics Data System (ADS)
Chen, Shao-Long; Okada, Nobuchika
2008-10-01
There are lots of new physics models which predict an extra neutral gauge boson, referred as Z‧-boson. In a certain class of these new physics models, the Z‧-boson has flavor-dependent couplings with the fermions in the Standard Model (SM). Based on a simple model in which couplings of the SM fermions in the third generation with the Z‧-boson are different from those of the corresponding fermions in the first two generations, we study the signatures of Z‧-boson at the Large Hadron Collider (LHC) and the International Linear Collider (ILC). We show that at the LHC, the Z‧-boson with mass around 1 TeV can be produced through the Drell-Yan processes and its dilepton decay modes provide us clean signatures not only for the resonant production of Z‧-boson but also for flavor-dependences of the production cross sections. We also study fermion pair productions at the ILC involving the virtual Z‧-boson exchange. Even though the center-of-energy of the ILC is much lower than a Z‧-boson mass, the angular distributions and the forward-backward asymmetries of fermion pair productions show not only sizable deviations from the SM predictions but also significant flavor-dependences.
Direct observation of how the heavy-fermion state develops in CeCoIn5
NASA Astrophysics Data System (ADS)
Chen, Q. Y.; Xu, D. F.; Niu, X. H.; Jiang, J.; Peng, R.; Xu, H. C.; Wen, C. H. P.; Ding, Z. F.; Huang, K.; Shu, L.; Zhang, Y. J.; Lee, H.; Strocov, V. N.; Shi, M.; Bisti, F.; Schmitt, T.; Huang, Y. B.; Dudin, P.; Lai, X. C.; Kirchner, S.; Yuan, H. Q.; Feng, D. L.
2017-07-01
Heavy-fermion systems share some of the strange metal phenomenology seen in other unconventional superconductors, providing a unique opportunity to set strange metals in a broader context. Central to understanding heavy-fermion systems is the interplay of localization and itinerancy. These materials acquire high electronic masses and a concomitant Fermi volume increase as the f electrons delocalize at low temperatures. However, despite the wide-spread acceptance of this view, a direct microscopic verification has been lacking. Here we report high-resolution angle-resolved photoemission measurements on CeCoIn5, a prototypical heavy-fermion compound, which spectroscopically resolve the development of band hybridization and the Fermi surface expansion over a wide temperature region. Unexpectedly, the localized-to-itinerant transition occurs at surprisingly high temperatures, yet f electrons are still largely localized even at the lowest temperature. These findings point to an unanticipated role played by crystal-field excitations in the strange metal behavior of CeCoIn5. Our results offer a comprehensive experimental picture of the heavy-fermion formation, setting the stage for understanding the emergent properties, including unconventional superconductivity, in this and related materials.
NASA Astrophysics Data System (ADS)
Xiao, R. C.; Cheung, C. H.; Gong, P. L.; Lu, W. J.; Si, J. G.; Sun, Y. P.
2018-06-01
k paths exactly with symmetry allow to find triply degenerate points (TDPs) in band structures. The paths that host the type-II Dirac points in PtSe2 family materials also have the spatial symmetry. However, due to Kramers degeneracy (the systems have both inversion symmetry and time reversal symmetry), the crossing points in them are Dirac ones. In this work, based on symmetry analysis, first-principles calculations, and method, we predict that PtSe2 family materials should undergo topological transitions if the inversion symmetry is broken, i.e. the Dirac fermions in PtSe2 family materials split into TDPs in PtSeTe family materials (PtSSe, PtSeTe, and PdSeTe) with orderly arranged S/Se (Se/Te). It is different from the case in high-energy physics that breaking inversion symmetry I leads to the splitting of Dirac fermion into Weyl fermions. We also address a possible method to achieve the orderly arranged in PtSeTe family materials in experiments. Our study provides a real example that Dirac points transform into TDPs, and is helpful to investigate the topological transition between Dirac fermions and TDP fermions.
Fermion superfluid with hybridized s- and p-wave pairings
NASA Astrophysics Data System (ADS)
Zhou, LiHong; Yi, Wei; Cui, XiaoLing
2017-12-01
Ever since the pioneering work of Bardeen, Cooper and Schrieffer in the 1950s, exploring novel pairing mechanisms for fermion superfluids has become one of the central tasks in modern physics. Here, we investigate a new type of fermion superfluid with hybridized s- and p-wave pairings in an ultracold spin-1/2 Fermi gas. Its occurrence is facilitated by the co-existence of comparable s- and p-wave interactions, which is realizable in a two-component 40K Fermi gas with close-by s- and p-wave Feshbach resonances. The hybridized superfluid state is stable over a considerable parameter region on the phase diagram, and can lead to intriguing patterns of spin densities and pairing fields in momentum space. In particular, it can induce a phase-locked p-wave pairing in the fermion species that has no p-wave interactions. The hybridized nature of this novel superfluid can also be confirmed by measuring the s- and p-wave contacts, which can be extracted from the high-momentum tail of the momentum distribution of each spin component. These results enrich our knowledge of pairing superfluidity in Fermi systems, and open the avenue for achieving novel fermion superfluids with multiple partial-wave scatterings in cold atomic gases.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Levay, Peter; Nagy, Szilvia; Pipek, Janos
An elementary formula for the von Neumann and Renyi entropies describing quantum correlations in two-fermionic systems having four single-particle states is presented. An interesting geometric structure of fermionic entanglement is revealed. A connection with the generalized Pauli principle is established.
Busch, Alisa B; Huskamp, Haiden A; Normand, Sharon-Lise T; Young, Alexander S; Goldman, Howard; Frank, Richard G
2006-06-01
Since the 1990s, parity laws have been implemented to reduce inequities in mental health coverage compared with that for general medical conditions. It is unclear if parity under managed care is associated with improvements in mental health treatment quality. Major depressive disorder (MDD) is a prevalent but often undetected and undertreated and thus could potentially benefit from parity implementation. The objective of this study was to examine the association between parity implementation and changes in MDD treatment quality in the Federal Employees' Health Benefits (FEHB) Program. We conducted retrospective analyses of insurance claims data. Logistic regression models estimated quality changes for MDD-diagnosed enrollees from pre- to postparity. Subjects included MDD-diagnosed FEHB insured enrollees, aged 18-64, across multiple states and 6 FEHB plans before (1999-2000) and after (2001-2002) parity implementation. Measures included receipt of any antidepressant or psychotherapy within a given calendar year of diagnosis; receipt of appropriate psychotherapy frequency/intensity and duration; and pharmacotherapy duration during acute-phase treatment episodes. Postparity, several plans improved significantly in the likelihood of receiving antidepressant medication. In the acute-phase episodes, the greatest improvement was seen in the likelihood of follow up >or=4 months. Few or no other changes were observed in the acute-phase treatment intensity or duration quality measures. Parity under managed care was associated with modest improvements. The observed improvements were consistent with secular trends in MDD treatment. Whereas mental health parity is an important policy goal, these results highlight its limitations: improving the financing of care may not be sufficient to improve quality.
Description of alternating-parity bands within the dinuclear-system model
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shneidman, T. M.; Adamian, G. G., E-mail: adamian@theor.jinr.ru; Antonenko, N. V.
2016-11-15
A cluster approach is used to describe ground-state-based alternating-parity bands in even–even nuclei and to study the band-termination mechanism. A method is proposed for testing the cluster nature of alternating-parity bands.
Behavioral health benefits for public employees: effect of mental health parity legislation.
Borzi, P C; Rosenbaum, S
2001-04-01
With the passage of the Mental Health Parity Act of 1996 (MHPA), Congress took an important first step toward equalizing treatment under medical plans between physical and mental illnesses by requiring parity in annual and lifetime dollar limits between physical and mental illness. But the Act was limited in scope: it did not mandate mental health benefits nor prohibit other common types of differentials between physical and mental illnesses, such as higher cost-sharing or lower limits on outpatient visits or inpatient treatments. Before Congress' action in 1996, a few of the states had adopted some type of parity requirement. Since 1996, state parity activity has accelerated.Recently, the Center for Health Services Research and Policy through a grant from the Substance Abuse and Mental Health Services Administration of the U.S. Department of Health and Human Services, examined contracts providing for mental health benefits for state employees in eight states to assess whether legislative attempts to require parity between physical and mental illnesses resulted in noticeable differences in behavioral health benefits for state employees. We concluded that, except in states that have mandated full parity for some or all types of mental illnesses, behavioral health benefits for state employees have not changed significantly as a result of the state parity laws, since they still remain subject to traditional restrictions, such as higher cost-sharing and greater limitations on outpatient visits and inpatient treatment days, than those imposed on physical illnesses. Thus the considerable state activity surrounding mental health parity may have little effect on state employees' access to mental health services, since although state laws required parity in dollar limitations, they generally permitted the continuation of other plan design features that are more restrictive for mental health coverage. However, many of the contracts we examined were multi-year contract and may not have fully reflected recent state activity. Moreover, if Congress renews the Mental Health Parity Act when it expires in September, 2001, and expands the scope of the Act to cover some of these other plan design features, states with more limited parity laws are likely to follow. In that case, perhaps state employees with mental illnesses may see significant change in the future.
Mapfumo, Lizwell; Muchenje, Voster; Mupangwa, John F; Scholtz, Michiel M
2017-10-01
The objective of this study was to determine the changes in biochemical indicators for nutritional stress from a herd of Boran and Nguni cows. A total of 40 cows (20 from each herd) were randomly selected for the study. The animals were identified according to their parities as follows: parity 1 (n = 8), parity 2 (n = 16), parity 3 (n = 8) and parity 4 (n = 8). Serum chemistry levels of glucose, total cholesterol, urea, creatinine, albumin, globulin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma glutylaminotransferase (GGT), leukocytes, erythrocytes, haemoglobin, packed cell volume (PCV) and platelet counts were determined for 12 consecutive months spanning across the wet and dry seasons. The Boran cows had different creatinine concentration levels at different parities. The Boran cows in parity 1 had the highest (P < 0.05) concentration of creatinine 87.2 ± 5.17 μmol/L than other cows in different parities within the herd. There were significant differences in enzymes such as AST, ALP and ALT among the herd and parities. Boran cows in parity 3 had the lowest (P < 0.05) AST concentration levels of 52.6 ± 3.48 U/L, Nguni cows in parity 4 had the highest concentration of ALP of 161.3 ± 8.10 U/L while Nguni cows in parity 1 had the highest concentration level of ALT 55.1 ± 1.56 U/L than all the cows within the same herd. The Nguni herd had significantly higher (P < 0.05) levels of creatinine in both the wet (97.8 ± 3.27 μmol/L) and dry seasons (108.7 ± 3.29 μmol/L) compared with the Boran herd. Cows from the Nguni herd maintained significantly higher amount of urea, creatinine, albumin and total protein in both the wet and dry seasons as compared with cows from the Boran herd. Cows from the Nguni herd maintained significantly higher amount of urea, creatinine, albumin and total protein in both the wet and dry seasons as compared with those from the Boran herd.