Phase structure, magnetic monopoles, and vortices in the lattice Abelian Higgs model
Ranft, J.; Kripfganz, J.; Ranft, G.
1983-07-15
We present Monte Carlo calculations of lattice Abelian Higgs models in four dimensions and with charges of the Higgs particles equal to q = 1, 2, and 6. The phase transitions are studied in the plane of the two coupling constants considering separately average plaquette and average link expectation values. The density of topological excitations is studied. In the confinement phase we find finite densities of magnetic-monopole currents, electric currents, and vortex currents. The magnetic-monopole currents vanish exponentially in the Coulomb phase. The density of electric currents and vortex currents is finite in the Coulomb phase and vanishes exponentially in the Higgs phase.
Non-Abelian vortices and non-Abelian statistics
Lo, H.; Preskill, J. )
1993-11-15
We study the interactions of non-Abelian vortices in two spatial dimensions. These interactions have novel features, because the Aharonov-Bohm effect enables a pair of vortices to exchange quantum numbers. The cross section for vortex-vortex scattering is typically a multivalued function of the scattering angle. There can be an exchange contribution to the vortex-vortex scattering amplitude that adds coherently with the direct amplitude, even if the two vortices have distinct quantum numbers. Thus two vortices can be indistinguishable'' even though they are not the same.
NASA Astrophysics Data System (ADS)
Chagoya, Javier; Tasinato, Gianmassimo
2016-02-01
Vortex solutions are topologically stable field configurations that can play an important role in condensed matter, field theory, and cosmology. We investigate vortex configuration in a 2+1 dimensional Abelian Higgs theory supplemented by higher order derivative self-interactions, related with Galileons. Our vortex solutions have features that make them qualitatively different from well-known Abrikosov-Nielsen-Olesen configurations, since the derivative interactions turn on gauge invariant field profiles that break axial symmetry. By promoting the system to a 3+1 dimensional string configuration, we study its gravitational backreaction. Our results are all derived within a specific, analytically manageable system, and might offer indications for understanding Galileonic interactions and screening mechanisms around configurations that are not spherically symmetric, but only at most cylindrically symmetric.
Geometry and energy of non-Abelian vortices
Manton, Nicholas S.; Rink, Norman A.
2011-04-15
We study pure Yang-Mills theory on {Sigma}xS{sup 2}, where {Sigma} is a compact Riemann surface, and invariance is assumed under rotations of S{sup 2}. It is well known that the self-duality equations in this setup reduce to vortex equations on {Sigma}. If the Yang-Mills gauge group is SU(2), the Bogomolny vortex equations of the Abelian Higgs model are obtained. For larger gauge groups, one generally finds vortex equations involving several matrix-valued Higgs fields. Here we focus on Yang-Mills theory with gauge group SU(N)/Z{sub N} and a special reduction which yields only one non-Abelian Higgs field. One of the new features of this reduction is the fact that while the instanton number of the theory in four dimensions is generally fractional with denominator N, we still obtain an integral vortex number in the reduced theory. We clarify the relation between these two topological charges at a bundle geometric level. Another striking feature is the emergence of nontrivial lower and upper bounds for the energy of the reduced theory on {Sigma}. These bounds are proportional to the area of {Sigma}. We give special solutions of the theory on {Sigma} by embedding solutions of the Abelian Higgs model into the non-Abelian theory, and we relate our work to the language of quiver bundles, which has recently proved fruitful in the study of dimensional reduction of Yang-Mills theory.
Fun with the Abelian Higgs model
NASA Astrophysics Data System (ADS)
Malinský, Michal
2013-05-01
In calculations of the elementary scalar spectra of spontaneously broken gauge theories there are a number of subtleties which, though it is often unnecessary to deal with them in the order-of-magnitude type of calculations, have to be taken into account if fully consistent results are sought for. Within the "canonical" effective-potential approach these are, for instance: the need to handle infinite series of nested commutators of derivatives of field-dependent mass matrices, the need to cope with spurious IR divergences emerging in the consistent leading-order approximation and, in particular, the need to account for the fine interplay between the renormalization effects in the one- and two-point Green functions which, indeed, is essential for the proper stable vacuum identification and, thus, for the correct interpretation of the results. In this note we illustrate some of these issues in the realm of the minimal Abelian Higgs model and two of its simplest extensions including extra heavy scalars in the spectrum in attempt to exemplify the key aspects of the usual "hierarchy problem" lore in a very specific and simple setting. We emphasize that, regardless of the omnipresent polynomial cut-off dependence in the one-loop corrections to the scalar two-point function, the physical Higgs boson mass is always governed by the associated symmetry-breaking VEV and, as such, it is generally as UV-robust as all other VEV-driven masses in the theory.
Non-Abelian vortices on a cylinder: Duality between vortices and walls
Eto, Minoru; Fujimori, Toshiaki; Isozumi, Youichi; Nitta, Muneto; Ohashi, Keisuke; Sakai, Norisuke; Ohta, Kazutoshi
2006-04-15
We investigate vortices on a cylinder in supersymmetric non-Abelian gauge theory with hypermultiplets in the fundamental representation. We identify moduli space of periodic vortices and find that a pair of wall-like objects appears as the vortex moduli is varied. Usual domain walls also can be obtained from the single vortex on the cylinder by introducing a twisted boundary condition. We can understand these phenomena as a T duality among D-brane configurations in type II superstring theories. Using this T-duality picture, we find a one-to-one correspondence between the moduli space of non-Abelian vortices and that of kinky D-brane configurations for domain walls.
Peristaltic modes of a single vortex in the Abelian Higgs model
Kojo, Toru; Suganuma, Hideo; Tsumura, Kyosuke
2007-05-15
Using the Abelian Higgs model, we study the radial excitations of single vortex and their propagation modes along the vortex line. We call such beyond-stringy modes peristaltic modes of single vortex. With the profile of the static vortex, we derive the vortex-induced potential, i.e., single-particle potential for the Higgs and the photon field fluctuations around the static vortex, and investigate the coherently propagating fluctuations which correspond to the vibration of the vortex. We derive, analyze, and numerically solve the field equations of the Higgs and the photon field fluctuations around the static vortex with various Ginzburg-Landau parameter {kappa} and topological charge n. Around the Bogomol'nyi-Prasad-Sommerfield value or critical coupling {kappa}{sup 2}=1/2, there appears a significant correlation between the Higgs and the photon field fluctuations mediated by the static vortex. As a result, for {kappa}{sup 2}=1/2, we find the characteristic new-type discrete pole of the peristaltic mode corresponding to the quasibound state of coherently fluctuating fields and the static vortex. We investigate its excitation energy, correlation energy of coherent fluctuations, spatial distributions, and the resulting magnetic flux behavior in detail. Our investigation covers not only usual type-II vortices with n=1 but also type-I and type-II vortices with n set-membership sign Z for the application to various general systems where the vortexlike objects behave as the essential degrees of freedom.
Phase transitions at strong coupling in the 2+1-d abelian Higgs model
NASA Astrophysics Data System (ADS)
MacKenzie, R. B.; Nebia-Rahal, Faïza; Paranjape, M. B.
2013-12-01
We study, using numerical Monte-Carlo simulations, an effective description of the 2+1 dimensional Abelian Higgs model which is valid at strong coupling, in the broken symmetry sector. In this limit, the massive gauge boson and the massive neutral Higgs decouple leaving only the massive vortices. The vortices have no long range interactions. We find a phase transition as the mass of the vortices is made lighter and lighter. At the transition, the contributions to the functional integral come from a so-called infinite vortex anti-vortex loop. Adding the Chern-Simons term simply counts the linking number between the vortices. We find that the Wilson loop exhibits perimeter law behaviour in both phases, although the polarization cloud increases by an order of magnitude at the transition. We also study the 't Hooft loop. We find the 't Hooft loop exhibits perimeter law behaviour in the presence of the Chern-Simons term but is trivial in its absence. Thus we have a theory with perimeter law for both the Wilson loop and the 't Hooft loop, but contains no massless particles.
Asymptotically free scaling solutions in non-Abelian Higgs models
NASA Astrophysics Data System (ADS)
Gies, Holger; Zambelli, Luca
2015-07-01
We construct asymptotically free renormalization group trajectories for the generic non-Abelian Higgs model in four-dimensional spacetime. These ultraviolet-complete trajectories become visible by generalizing the renormalization/boundary conditions in the definition of the correlation functions of the theory. Though they are accessible in a controlled weak-coupling analysis, these trajectories originate from threshold phenomena which are missed in a conventional perturbative analysis relying on the deep Euclidean region. We identify a candidate three-parameter family of renormalization group trajectories interconnecting the asymptotically free ultraviolet regime with a Higgs phase in the low-energy limit. We provide estimates of their low-energy properties in the light of a possible application to the standard model Higgs sector. Finally, we find a two-parameter subclass of asymptotically free Coleman-Weinberg-type trajectories that do not suffer from a naturalness problem.
The Abelian Higgs model on Optical Lattice?
NASA Astrophysics Data System (ADS)
Meurice, Yannick; Tsai, Shan-Wen; Bazavov, Alexei; Zhang, Jin
2015-03-01
We study the Lattice Gauge Theory of the U(1)-Higgs model in 1+1 dimensions in the strongly coupled regime. We discuss the plaquette corrections to the effective theory where link variables are integrated out. We discuss matching with the second-order perturbation theory effective Hamiltonian for various Bose-Hubbard models. This correspondence can be exploited for building a lattice gauge theory simulator on optical lattices. We propose to implement the quantum rotors which appear in the Hamiltonian formulation using Bose mixtures or p-orbitals. Recent progress on magnetic effects in 2+1 dimensions will be discussed. Supported by the Army Research Office of the Department of Defense under Award Number W911NF-13-1-0119.
Effective action for the Abelian Higgs model in FLRW
George, Damien P.; Mooij, Sander; Postma, Marieke E-mail: smooij@nikhef.nl
2012-11-01
We compute the divergent contributions to the one-loop action of the U(1) Abelian Higgs model. The calculation allows for a Friedmann-Lemaitre-Robertson-Walker space-time and a time-dependent expectation value for the scalar field. Treating the time-dependent masses as two-point interactions, we use the in-in formalism to compute the first, second and third order graphs that contribute quadratic and logarithmic divergences to the effective scalar action. Working in R{sub ξ} gauge we show that the result is gauge invariant upon using the equations of motion.
Non-Abelian dynamics in the resonant decay of the Higgs after inflation
Enqvist, Kari; Nurmi, Sami; Rusak, Stanislav E-mail: sami.nurmi@helsinki.fi
2014-10-01
We study the resonant decay of the Higgs condensate into weak gauge bosons after inflation and estimate the corrections arising from the non-Abelian self-interactions of the gauge fields. We find that non-Abelian interaction terms induce an effective mass which tends to shut down the resonance. For the broad resonance relevant for the Standard Model Higgs the produced gauge particles backreact on the dynamics of the Higgs condensate before the non-Abelian terms grow large. The non-Abelian terms can however significantly affect the final stages of the resonance after the backreaction. In the narrow resonance regime, which may be important for extensions of the Standard Model, the non-Abelian terms affect already the linear stage and terminate the resonance before the Higgs condensate is affected by the backreaction of decay products.
Non-Abelian vortices at weak and strong coupling in mass deformed ABJM theory
NASA Astrophysics Data System (ADS)
Auzzi, Roberto; Kumar, S. Prem
2009-10-01
We find half-BPS vortex solitons, at both weak and strong coupling, in the Script N = 6 supersymmetric mass deformation of ABJM theory with U(N) × U(N) gauge symmetry and Chern-Simons level k. The strong coupling gravity dual is obtained by performing a Bbb Zk quotient of the Script N = 8 supersymmetric eleven dimensional supergravity background of Lin, Lunin and Maldacena corresponding to the mass deformed M2-brane theory. At weak coupling, the BPS vortices preserving six supersymmetries are found in the Higgs vacuum of the theory where the gauge symmetry is broken to U(1) × U(1). The classical vortex solitons break a colour-flavour locked global symmetry resulting in non-Abelian internal orientational moduli and a CP1 moduli space of solutions. At strong coupling and large k, upon reduction to type IIA strings, the vortex moduli space and its action are computed by a probe D0-brane in the dual geometry. The mass of the D0-brane matches the classical vortex mass. However, the gravity picture exhibits a six dimensional moduli space of solutions, a section of which can be identified as the CP1 we find classically, along with a Dirac monopole connection of strength k. It is likely that the extra four dimensions in the moduli space are an artifact of the strong coupling limit and of the supergravity approximation.
Fixed point structure of the Abelian Higgs model
NASA Astrophysics Data System (ADS)
Fejős, G.; Hatsuda, T.
2016-06-01
The order of the superconducting phase transition is analyzed via the functional renormalization group approach. For the first time, we derive fully analytic expressions for the β functions of the charge and the self-coupling in the Abelian Higgs model with one complex scalar field in d =3 dimensions that support the existence of two charged fixed points: an infrared (IR) stable fixed point describing a second-order phase transition and a tricritical fixed point controlling the region of the parameter space that is attracted by the former one. It is found that the region separating first- and second-order transitions can be uniquely characterized by the Ginzburg-Landau parameter κ , and the system undergoes a second-order transition only if κ >κc≈0.62 /√{2 }.
A non-perturbative argument for the non-abelian Higgs mechanism
De Palma, G.; Strocchi, F.
2013-09-15
The evasion of massless Goldstone bosons by the non-abelian Higgs mechanism is proved by a non-perturbative argument in the local BRST gauge. -- Highlights: •The perturbative explanation of the Higgs mechanism (HM) is not under mathematical control. •We offer a non-perturbative proof of the absence of Goldstone bosons from the non-abelian HM. •Our non-perturbative proof in the BRST gauge avoids a mean field ansatz and expansion.
Energy-momentum correlations for Abelian Higgs cosmic strings
NASA Astrophysics Data System (ADS)
Daverio, David; Hindmarsh, Mark; Kunz, Martin; Lizarraga, Joanes; Urrestilla, Jon
2016-04-01
We report on the energy-momentum correlators obtained with recent numerical simulations of the Abelian Higgs model, essential for the computation of cosmic microwave background and matter perturbations of cosmic strings. Due to significant improvements both in raw computing power and in our parallel simulation framework, the dynamical range of the simulations has increased fourfold both in space and time, and for the first time we are able to simulate strings with a constant physical width in both the radiation and matter eras. The new simulations improve the accuracy of the measurements of the correlation functions at the horizon scale and confirm the shape around the peak. The normalization is slightly higher in the high wave-number tails, due to a small increase in the string density. We study, for the first time, the behavior of the correlators across cosmological transitions and discover that the correlation functions evolve adiabatically; i.e., the network adapts quickly to changes in the expansion rate. We propose a new method for constructing source functions for Einstein-Boltzmann integrators, comparing it with two other methods previously used. The new method is more consistent, easier to implement, and significantly more accurate.
Topological vortices in generalized Born-Infeld-Higgs electrodynamics
NASA Astrophysics Data System (ADS)
Casana, R.; Hora, E. da; Rubiera-Garcia, D.; Santos, C. dos
2015-08-01
A consistent BPS formalism to study the existence of topological axially symmetric vortices in generalized versions of the Born-Infeld-Higgs electrodynamics is implemented. Such a generalization modifies the field dynamics via the introduction of three nonnegative functions depending only in the Higgs field, namely, , , and . A set of first-order differential equations is attained when these functions satisfy a constraint related to the Ampère law. Such a constraint allows one to minimize the system's energy in such way that it becomes proportional to the magnetic flux. Our results provides an enhancement of the role of topological vortex solutions in Born-Infeld-Higgs electrodynamics. Finally, we analyze a set of models entailing the recovery of a generalized version of Maxwell-Higgs electrodynamics in a certain limit of the theory.
Fermion structure of non-Abelian vortices in high density QCD
Yasui, Shigehiro; Itakura, Kazunori; Nitta, Muneto
2010-05-15
We study the internal structure of a non-Abelian vortex in color superconductivity with respect to quark degrees of freedom. Stable non-Abelian vortices appear in the color-flavor-locked phase whose symmetry SU(3){sub c+L+R} is further broken to SU(2){sub c+L+R} x U(1){sub c+L+R} at the vortex cores. Microscopic structure of vortices at scales shorter than the coherence length can be analyzed by the Bogoliubov-de Gennes equation (rather than the Ginzburg-Landau equation). We obtain quark spectra from the Bogoliubov-de Gennes equation by treating the diquark gap having the vortex configuration as a background field. We find that there are massless modes (zero modes) well-localized around a vortex, in the triplet and singlet states of the unbroken symmetry SU(2){sub c+L+R} x U(1){sub c+L+R}. The velocities v{sub i} of the massless modes (i=t, s for triplet and singlet) change at finite chemical potential {mu}{ne}0, and decrease as {mu} becomes large. Therefore, low energy excitations in the vicinity of the vortices are effectively described by 1+1 dimensional massless fermions whose velocities are reduced v{sub i}<1.
NASA Astrophysics Data System (ADS)
Borgh, Magnus O.; Ruostekoski, Janne
2016-05-01
We demonstrate that multiple interaction-dependent defect core structures as well as dynamics of non-Abelian vortices can be realized in the biaxial nematic (BN) phase of a spin-2 atomic Bose-Einstein condensate (BEC). An experimentally simple protocol may be used to break degeneracy with the uniaxial nematic phase. We show that a discrete spin-space symmetry in the core may be reflected in a breaking of its spatial symmetry. The discrete symmetry of the BN order parameter leads to non-commuting vortex charges. We numerically simulate reconnection of non-Abelian vortices, demonstrating formation of the obligatory rung vortex. In addition to atomic BECs, non-Abelian vortices are theorized in, e.g., liquid crystals and cosmic strings. Our results suggest the BN spin-2 BEC as a prime candidate for their realization. We acknowledge financial support from the EPSRC.
Three phases in the three-dimensional Abelian-Higgs model with nonlocal gauge interactions
Takashima, Shunsuke; Ichinose, Ikuo; Matsui, Tetsuo; Sakakibara, Kazuhiko
2006-08-15
We study the phase structure of the three-dimensional (3D) nonlocal compact U(1) lattice gauge theory coupled with a Higgs field by Monte Carlo simulations. The nonlocal interactions among gauge variables are along the temporal direction and mimic the effect of local coupling to massless particles. In contrast to the 3D local Abelian-Higgs model having only the confinement phase, the present model exhibits the confinement, Higgs, and Coulomb phases separated by three second-order transition lines emanating from a triple point. This result is relevant not only to the 3D massless QED coupled with a Higgs field but also to electron fractionalization phenomena in strongly correlated electron systems like the high-T{sub c} superconductors and the fractional quantum Hall effect.
The Abelian Higgs model and a minimal length in an un-particle scenario
NASA Astrophysics Data System (ADS)
Gaete, Patricio; Spallucci, Euro
2014-01-01
We consider both the Abelian Higgs model and the impact of a minimal length in the un-particle sector. It is shown that even if the Higgs field takes a non-vanishing vacuum expectation value (v.e.v.), gauge interaction keeps its long-range character leading to an effective gauge symmetry restoration. The effect of a quantum-gravity-induced minimal length on a physical observable is then estimated by using a physically based alternative to the usual Wilson loop approach. Interestingly, we obtain an ultraviolet finite interaction energy described by a confluent hypergeometric function, which shows a remarkable richness of behavior.
Symmetric solitonic excitations of the (1 + 1)-dimensional Abelian-Higgs classical vacuum.
Diakonos, F K; Katsimiga, G C; Maintas, X N; Tsagkarakis, C E
2015-02-01
We study the classical dynamics of the Abelian-Higgs model in (1 + 1) space-time dimensions for the case of strongly broken gauge symmetry. In this limit the wells of the potential are almost harmonic and sufficiently deep, presenting a scenario far from the associated critical point. Using a multiscale perturbation expansion, the equations of motion for the fields are reduced to a system of coupled nonlinear Schrödinger equations. Exact solutions of the latter are used to obtain approximate analytical solutions for the full dynamics of both the gauge and Higgs field in the form of oscillons and oscillating kinks. Numerical simulations of the exact dynamics verify the validity of these solutions. We explore their persistence for a wide range of the model's single parameter, which is the ratio of the Higgs mass (m(H)) to the gauge-field mass (m(A)). We show that only oscillons oscillating symmetrically with respect to the "classical vacuum," for both the gauge and the Higgs field, are long lived. Furthermore, plane waves and oscillating kinks are shown to decay into oscillon-like patterns, due to the modulation instability mechanism. PMID:25768621
Quiver gauge theory of non-Abelian vortices and noncommutative instantons in higher dimensions
Popov, Alexander D.; Szabo, Richard J.
2006-01-15
We construct explicit Bogomolnyi, Prasad, Sommerfeld (BPS) and non-BPS solutions of the Yang-Mills equations on the noncommutative space R{sub {theta}}{sup 2n}xS{sup 2} which have manifest spherical symmetry. Using SU(2)-equivariant dimensional reduction techniques, we show that the solutions imply an equivalence between instantons on R{sub {theta}}{sup 2n}xS{sup 2} and non-Abelian vortices on R{sub {theta}}{sup 2n}, which can be interpreted as a blowing-up of a chain of D0-branes on R{sub {theta}}{sup 2n} into a chain of spherical D2-branes on R{sub {theta}}{sup 2n}xS{sup 2}. The low-energy dynamics of these configurations is described by a quiver gauge theory which can be formulated in terms of new geometrical objects generalizing superconnections. This formalism enables the explicit assignment of D0-brane charges in equivariant K-theory to the instanton solutions.
Gauge-invariant implementation of the Abelian-Higgs model on optical lattices
NASA Astrophysics Data System (ADS)
Bazavov, A.; Meurice, Y.; Tsai, S.-W.; Unmuth-Yockey, J.; Zhang, Jin
2015-10-01
We present a gauge-invariant effective action for the Abelian-Higgs model (scalar electrodynamics) with a chemical potential μ on a (1 +1 )-dimensional lattice. This formulation provides an expansion in the hopping parameter κ which we test with Monte Carlo simulations for a broad range of the inverse gauge coupling βp l=1 /g2 and small values of the scalar self-coupling λ . In the opposite limit of infinitely large λ , the partition function can be written as a traced product of local tensors which allows us to write exact blocking formulas. Gauss's law is automatically satisfied and the introduction of μ has consequences only if we have an external electric field, g2=0 or an explicit gauge symmetry breaking. The time-continuum limit of the blocked transfer matrix can be obtained numerically and, for g2=0 and a spin-1 truncation, the small volume energy spectrum is identical to the low energy spectrum of a two-species Bose-Hubbard model in the limit of large on-site repulsion. We extend this procedure for finite βp l and derive a spin-1 approximation of the Hamiltonian. It involves new terms corresponding to transitions among the two species in the Bose-Hubbard model. We propose an optical lattice implementation involving a ladder structure.
The existence of self-dual vortices in a non-Abelian {Phi}{sup 2} Chern-Simons theory
Chen Shouxin; Wang Ying
2010-09-15
Applying the dynamic shooting method, we proved the existence of nontopological radially symmetric n-vortex solutions to the self-dual equation in non-Abelian Chern-Simons gauge theory with a {Phi}{sup 2}-type potential. Moreover, we obtained all possible radially symmetric nontopological bare (or 0-vortex) solutions in the non-Abelian Chern-Simons model. Meanwhile, we established the asymptotic behavior for the solutions as |x|{yields}{infinity}.
Bevis, Neil; Hindmarsh, Mark; Kunz, Martin; Urrestilla, Jon
2007-03-15
We present the first field-theoretic calculations of the contribution made by cosmic strings to the temperature power spectrum of the cosmic microwave background (CMB). Unlike previous work, in which strings were modeled as idealized one-dimensional objects, we evolve the simplest example of an underlying field theory containing local U(1) strings, the Abelian Higgs model. Limitations imposed by finite computational volumes are overcome using the scaling property of string networks and a further extrapolation related to the lessening of the string width in comoving coordinates. The strings and their decay products, which are automatically included in the field theory approach, source metric perturbations via their energy-momentum tensor, the unequal-time correlation functions of which are used as input into the CMB calculation phase. These calculations involve the use of a modified version of CMBEASY, with results provided over the full range of relevant scales. We find that the string tension {mu} required to normalize to the WMAP 3-year data at multipole l=10 is G{mu}=[2.04{+-}0.06(stat.){+-}0.12(sys.)]x10{sup -6}, where we have quoted statistical and systematic errors separately, and G is Newton's constant. This is a factor 2-3 higher than values in current circulation.
Classical dynamics of the Abelian Higgs model from the critical point and beyond
NASA Astrophysics Data System (ADS)
Katsimiga, G. C.; Diakonos, F. K.; Maintas, X. N.
2015-09-01
We present two different families of solutions of the U(1)-Higgs model in a (1 + 1) dimensional setting leading to a localization of the gauge field. First we consider a uniform background (the usual vacuum), which corresponds to the fully higgsed-superconducting phase. Then we study the case of a non-uniform background in the form of a domain wall which could be relevantly close to the critical point of the associated spontaneous symmetry breaking. For both cases we obtain approximate analytical nodeless and nodal solutions for the gauge field resulting as bound states of an effective Pöschl-Teller potential created by the scalar field. The two scenaria differ only in the scale of the characteristic localization length. Numerical simulations confirm the validity of the obtained analytical solutions. Additionally we demonstrate how a kink may be used as a mediator driving the dynamics from the critical point and beyond.
Superconducting vortices in semilocal models.
Forgács, Péter; Reuillon, Sébastien; Volkov, Mikhail S
2006-02-01
It is shown that the SU(2) semilocal model--the Abelian Higgs model with two complex scalars--admits a new class of stationary, straight string solutions carrying a persistent current and having finite energy per unit length. In the plane orthogonal to their direction they correspond to a nontrivial deformation of the embedded Abrikosov-Nielsen-Olesen (ANO) vortices by the current flowing through them. The new solutions bifurcate with the ANO vortices in the limit of vanishing current. They can be either static or stationary. In the stationary case, the relative phase of the two scalars rotates at constant velocity, giving rise to an electric field and angular momentum, while the energy remains finite. The new static vortex solutions have lower energy than the ANO vortices and could be of considerable importance in various physical systems (from condensed matter to cosmic strings). PMID:16486806
Majorana meets Coxeter: Non-Abelian Majorana fermions and non-Abelian statistics
Yasui, Shigehiro; Itakura, Kazunori; Nitta, Muneto
2011-04-01
We discuss statistics of vortices having zero-energy non-Abelian Majorana fermions inside them. Considering the system of multiple non-Abelian vortices, we derive a non-Abelian statistics that differs from the previously derived non-Abelian statistics. The non-Abelian statistics presented here is given by a tensor product of two different groups, namely the non-Abelian statistics obeyed by the Abelian Majorana fermions and the Coxeter group. The Coxeter group is a symmetric group related to the symmetry of polytopes in a high-dimensional space. As the simplest example, we consider the case in which a vortex contains three Majorana fermions that are mixed with each other under the SO(3) transformations. We concretely present the representation of the Coxeter group in our case and its geometrical expressions in the high-dimensional Hilbert space constructed from non-Abelian Majorana fermions.
Some exact BPS solutions for exotic vortices and monopoles
NASA Astrophysics Data System (ADS)
Ramadhan, Handhika S.
2016-07-01
We present several analytical solutions of BPS vortices and monopoles in the generalized Abelian Maxwell-Higgs and Yang-Mills-Higgs theories, respectively. These models have recently been extensively studied and several exact solutions have already been obtained in [1,2]. In each theory, the dynamics is controlled by the additional two positive scalar-field-dependent functions, f (| ϕ |) and w (| ϕ |). For the case of vortices, we work in the ordinary symmetry-breaking Higgs potential, while for the case of monopoles we have the ordinary condition of the Prasad-Sommerfield limit. Our results generalize the exact solutions found previously. We also present solutions for BPS vortices with higher winding number. These solutions suffer from the condition that w (| ϕ |) has negative value at some finite range of r, but we argue that since it satisfies the weaker positive-value conditions then the corresponding energy density is still positive-definite and, thus, they are acceptable BPS solutions.
Chern-Simons-Higgs transitions out of topological superconducting phases
NASA Astrophysics Data System (ADS)
Clarke, David J.; Nayak, Chetan
2015-10-01
In this study, we examine effective field theories of superconducting phases with topological order, making a connection to proposed realizations of exotic topological phases (including those hosting Ising and Fibonacci anyons) in superconductor-quantum Hall heterostructures. Our effective field theories for the non-Abelian superconducting states are non-Abelian Chern-Simons theories in which the condensation of vortices carrying non-Abelian gauge flux leads to the associated Abelian quantum Hall states. This Chern-Simons-Higgs condensation process is dual to the emergence of superconducting non-Abelian topological phases in coupled chain constructions. In such transitions, the chiral central charge of the system generally changes, so they fall outside the description of bosonic condensation transitions put forth by Bais and Slingerland [F. A. Bais and J. K. Slingerland, Phys. Rev. B 79, 045316 (2009), 10.1103/PhysRevB.79.045316] (though the two approaches agree when the described transitions coincide). Our condensation process may be generalized to Chern-Simons theories based on arbitrary Lie groups, always describing a transition from a Lie algebra to its Cartan subalgebra. We include several instructive examples of such transitions.
Universal Reconnection of Non-Abelian Cosmic Strings
Eto, Minoru; Hashimoto, Koji; Marmorini, Giacomo; Nitta, Muneto; Ohashi, Keisuke; Vinci, Walter
2007-03-02
We show that local and semilocal strings in Abelian and non-Abelian gauge theories with critical couplings always reconnect classically in collision, by using moduli space approximation. The moduli matrix formalism explicitly identifies a well-defined set of the vortex moduli parameters. Our analysis of generic geodesic motion in terms of those shows right-angle scattering in head-on collision of two vortices, which is known to give the reconnection of the strings.
Universal reconnection of non-Abelian cosmic strings.
Eto, Minoru; Hashimoto, Koji; Marmorini, Giacomo; Nitta, Muneto; Ohashi, Keisuke; Vinci, Walter
2007-03-01
We show that local and semilocal strings in Abelian and non-Abelian gauge theories with critical couplings always reconnect classically in collision, by using moduli space approximation. The moduli matrix formalism explicitly identifies a well-defined set of the vortex moduli parameters. Our analysis of generic geodesic motion in terms of those shows right-angle scattering in head-on collision of two vortices, which is known to give the reconnection of the strings. PMID:17359147
NASA Technical Reports Server (NTRS)
Dowker, Fay; Gregory, Ruth; Traschen, Jennie
1991-01-01
We argue the existence of solutions of the Euclidean Einstein equations that correspond to a vortex sitting at the horizon of a black hole. We find the asymptotic behaviors, at the horizon and at infinity, of vortex solutions for the gauge and scalar fields in an abelian Higgs model on a Euclidean Schwarzschild background and interpolate between them by integrating the equations numerically. Calculating the backreaction shows that the effect of the vortex is to cut a slice out of the Schwarzschild geometry. Consequences of these solutions for black hole thermodynamics are discussed.
Breaking an Abelian gauge symmetry near a black hole horizon
Gubser, Steven S.
2008-09-15
I argue that coupling the Abelian Higgs model to gravity plus a negative cosmological constant leads to black holes which spontaneously break the gauge invariance via a charged scalar condensate slightly outside their horizon. This suggests that black holes can superconduct.
Infrared Maximally Abelian Gauge
Mendes, Tereza; Cucchieri, Attilio; Mihara, Antonio
2007-02-27
The confinement scenario in Maximally Abelian gauge (MAG) is based on the concepts of Abelian dominance and of dual superconductivity. Recently, several groups pointed out the possible existence in MAG of ghost and gluon condensates with mass dimension 2, which in turn should influence the infrared behavior of ghost and gluon propagators. We present preliminary results for the first lattice numerical study of the ghost propagator and of ghost condensation for pure SU(2) theory in the MAG.
Potential vorticity in magnetohydrodynamics
NASA Astrophysics Data System (ADS)
Webb, G. M.; Mace, R. L.
2015-01-01
A version of Noether's second theorem using Lagrange multipliers is used to investigate fluid relabelling symmetries conservation laws in magnetohydrodynamics (MHD). We obtain a new generalized potential vorticity type conservation equation for MHD which takes into account entropy gradients and the J × B force on the plasma due to the current J and magnetic induction B. This new conservation law for MHD is derived by using Noether's second theorem in conjunction with a class of fluid relabelling symmetries in which the symmetry generator for the Lagrange label transformations is non-parallel to the magnetic field induction in Lagrange label space. This is associated with an Abelian Lie pseudo algebra and a foliated phase space in Lagrange label space. It contains as a special case Ertel's theorem in ideal fluid mechanics. An independent derivation shows that the new conservation law is also valid for more general physical situations.
Stirring vortices with vorticity holes
NASA Astrophysics Data System (ADS)
Velasco Fuentes, Oscar
2012-11-01
A vorticity hole is a region with, in absolute value, significantly lower vorticity than its surroundings. Here we discuss the dynamics of a Rankine vortex with two equal circular holes. If a symmetric initial condition is assumed, the evolution depends on three parameters: the vorticity drop, the hole size and the distance between the holes. We computed the evolution with a contour-dynamics model and quantified the stirring of fluid particles using finite-time Lyapunov exponents and Melnikov's method. The vorticity holes evolve similarly to a pair of vortices in an otherwise quiescent fluid, although they are additionally affected by their interaction with the boundary of the Rankine vortex. The strongest stirring occurs when the holes interact elastically and then always in the center of the vortex. This result contradicts the generally accepted notion that vortices are regions of null to weak stirring.
Nonrelativistic limit of the abelianized ABJM model and the ADS/CMT correspondence
NASA Astrophysics Data System (ADS)
Lopez-Arcos, Cristhiam; Murugan, Jeff; Nastase, Horatiu
2016-05-01
We consider the nonrelativistic limit of the abelian reduction of the massive ABJM model proposed in [1], obtaining a supersymmetric version of the Jackiw-Pi model. The system exhibits an N=2 Super-Schrödinger symmetry with the Jackiw-Pi vortices emerging as BPS solutions. We find that this (2 + 1)-dimensional abelian field theory is dual to a certain (3+1)-dimensional gravity theory that differs somewhat from previously considered abelian condensed matter stand-ins for the ABJM model. We close by commenting on progress in the top-down realization of the AdS/CMT correspondence in a critical string theory.
Condensing Non-Abelian Quasiparticles
Hermanns, M.
2010-02-05
A most interesting feature of certain fractional quantum Hall states is that their quasiparticles obey non-Abelian fractional statistics. So far, candidate non-Abelian wave functions have been constructed from conformal blocks in cleverly chosen conformal field theories. In this work we present a hierarchy scheme by which we can construct daughter states by condensing non-Abelian quasiparticles (as opposed to quasiholes) in a parent state, and show that the daughters have a non-Abelian statistics that differs from the parent. In particular, we discuss the daughter of the bosonic, spin-polarized Moore-Read state at nu=4/3 as an explicit example.
Generalized self-dual Chern-Simons vortices
Bazeia, D.; Hora, E. da; Santos, C. dos; Menezes, R.
2010-06-15
We search for vortices in a generalized Abelian Chern-Simons model with a nonstandard kinetic term. We illustrate our results, plotting and comparing several features of the vortex solution of the generalized model with those of the vortex solution found in the standard Chern-Simons model.
Center vortices as composites of monopole fluxes
NASA Astrophysics Data System (ADS)
Deldar, S.; Nejad, S. M. Hosseini
2016-01-01
We study the relation between the flux of a center vortex obtained from the center vortex model and the flux formed between monopoles from the Abelian gauge fixing method. Motivated by the Monte Carlo simulations which have shown that almost all monopoles are sitting on the top of vortices, we construct the fluxes of center vortices for SU (2) and SU (3) gauge groups using fractional fluxes of monopoles. Then, we compute the potentials in the fundamental representation induced by center vortices and fractional fluxes of monopoles. We show that by combining the fractional fluxes of monopoles one can produce the center vortex fluxes for SU (3) gauge group in a "center vortex model". Comparing the potentials, we conclude that the fractional fluxes of monopoles attract each other.
Moduli of Vortices and Grassmann Manifolds
NASA Astrophysics Data System (ADS)
Biswas, Indranil; Romão, Nuno M.
2013-05-01
We use the framework of Quot schemes to give a novel description of the moduli spaces of stable n-pairs, also interpreted as gauged vortices on a closed Riemann surface Σ with target {Mat_{r × n}({C})}, where n ≥ r. We then show that these moduli spaces embed canonically into certain Grassmann manifolds, and thus obtain natural Kähler metrics of Fubini-Study type. These spaces are smooth at least in the local case r = n. For abelian local vortices we prove that, if a certain "quantization" condition is satisfied, the embedding can be chosen in such a way that the induced Fubini-Study structure realizes the Kähler class of the usual L 2 metric of gauged vortices.
Symmetries of abelian orbifolds
NASA Astrophysics Data System (ADS)
Hanany, Amihay; Seong, Rak-Kyeong
2011-01-01
Using the Polya Enumeration Theorem, we count with particular attention to {{{{mathbb{C}^3}}} left/ {Γ } right.} up to {{{{mathbb{C}^6}}} left/ {Γ } right.} , abelian orbifolds in various dimensions which are invariant under cycles of the permutation group S D . This produces a collection of multiplicative sequences, one for each cycle in the Cycle Index of the permutation group. A multiplicative sequence is controlled by its values on prime numbers and their pure powers. Therefore, we pay particular attention to orbifolds of the form {{{{mathbb{C}^D}}} left/ {Γ } right.} where the order of Γ is p α. We propose a generalization of these sequences for any D and any p.
Lattice calculation of the decay of primordial Higgs condensate
NASA Astrophysics Data System (ADS)
Enqvist, Kari; Nurmi, Sami; Rusak, Stanislav; Weir, David J.
2016-02-01
We study the resonant decay of the primordial Standard Model Higgs condensate after inflation into SU(2) gauge bosons on the lattice. We find that the non-Abelian interactions between the gauge bosons quickly extend the momentum distribution towards high values, efficiently destroying the condensate after the onset of backreaction. For the inflationary scale H = 108 GeV, we find that 90% of the Higgs condensate has decayed after n~ 10 oscillation cycles. This differs significantly from the Abelian case where, given the same coupling strengths, most of the condensate would persist after the resonance.
Minimal non-Abelian model of atomic dark matter
NASA Astrophysics Data System (ADS)
Choquette, Jeremie; Cline, James M.
2015-12-01
A dark sector resembling the Standard Model, where the abundance of matter is explained by baryon and lepton asymmetries and stable constituents bind to form atoms, is a theoretically appealing possibility. We show that a minimal model with a hidden SU(2) gauge symmetry broken to U(1), with a Dirac fermion doublet, suffices to realize this scenario. Supplemented with a dark Higgs doublet that gets no vacuum expectation value, we readily achieve the dark matter asymmetry through leptogenesis. The model can simultaneously have three portals to the Standard Model, through the Higgs, non-Abelian kinetic mixing, and the heavy neutrino, with interesting phenomenology for direct and collider searches, as well as cosmologically relevant dark matter self-interactions. Exotic bound states consisting of two fermions and a doubly charged vector boson can exist in one phase of the theory.
Detecting 3d Non-Abelian Anyons via Adiabatic Cooling
NASA Astrophysics Data System (ADS)
Yamamoto, Seiji; Freedman, Michael; Yang, Kun
2011-03-01
Majorana fermions lie at the heart of a number of recent developments in condensed matter physics. One important application is the realization of non-abelian statistics and consequently a foundation for topological quantum computation. Theoretical propositions for Majorana systems abound, but experimental detection has proven challenging. Most attempts involve interferometry, but the degeneracy of the anyon state can be leveraged to produce a cooling effect, as previously shown in 2d. We apply this method of anyon detection to the 3d anyon model of Teo and Kane. Like the Fu-Kane model, this involves a hybrid system of topological insulator (TI) and superconductor (SC). The Majorana modes are localized to anisotropic hedgehogs in the order parameter which appear at the TI-SC interface. The effective model bears some resemblance to the non-Abelian Higgs model with scalar coupling as studied, for example, by Jackiw and Rebbi. In order to make concrete estimates relevant to experiments, we use parameters appropriate to Ca doped Bi 2 Se 3 as the topological insulator and Cu doped Bi 2 Se 3 as the superconductor. We find a temperature window in the milli-Kelvin regime where the presence of 3d non-abelian anyons will lead to an observable cooling effect.
Coverings of topological semi-abelian algebras
NASA Astrophysics Data System (ADS)
Mucuk, Osman; Demir, Serap
2016-08-01
In this work, we study on a category of topological semi-abelian algebras which are topological models of given an algebraic theory T whose category of models is semi-abelian; and investigate some results on the coverings of topological models of such theories yielding semi-abelian categories. We also consider the internal groupoid structure in the semi-abelian category of T-algebras, and give a criteria for the lifting of internal groupoid structure to the covering groupoids.
Two-component Abelian sandpile models.
Alcaraz, F C; Pyatov, P; Rittenberg, V
2009-04-01
In one-component Abelian sandpile models, the toppling probabilities are independent quantities. This is not the case in multicomponent models. The condition of associativity of the underlying Abelian algebras imposes nonlinear relations among the toppling probabilities. These relations are derived for the case of two-component quadratic Abelian algebras. We show that Abelian sandpile models with two conservation laws have only trivial avalanches. PMID:19518280
Introducing Abelian Groups Using Bullseyes and Jenga
ERIC Educational Resources Information Center
Smith, Michael D.
2016-01-01
The purpose of this article is to share a new approach for introducing students to the definition and standard examples of Abelian groups. The definition of an Abelian group is revised to include six axioms. A bullseye provides a way to visualize elementary examples and non-examples of Abelian groups. An activity based on the game of Jenga is used…
Mohammed, Asadig; Murugan, Jeff; Nastase, Horatiu
2012-11-01
We present an embedding of the three-dimensional relativistic Landau-Ginzburg model for condensed matter systems in an N = 6, U(N) × U(N) Chern-Simons-matter theory [the Aharony-Bergman-Jafferis-Maldacena model] by consistently truncating the latter to an Abelian effective field theory encoding the collective dynamics of O(N) of the O(N(2)) modes. In fact, depending on the vacuum expectation value on one of the Aharony-Bergman-Jafferis-Maldacena scalars, a mass deformation parameter μ and the Chern-Simons level number k, our Abelianization prescription allows us to interpolate between the Abelian Higgs model with its usual multivortex solutions and a Ø(4) theory. We sketch a simple condensed matter model that reproduces all the salient features of the Abelianization. In this context, the Abelianization can be interpreted as giving a dimensional reduction from four dimensions. PMID:23215268
Inverse avalanches on Abelian sandpiles
Chau, H.F. Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080 )
1994-11-01
A simple and computationally efficient way of finding inverse avalanches for Abelian sandpiles, called the inverse particle addition operator, is presented. In addition, the method is shown to be optimal in the sense that it requires the minimum amount of computation among methods of the same kind. The method is also conceptually succinct because avalanche and inverse avalanche are placed in the same footing.
Dowling, T.E.; Spiegel, E.A. )
1990-12-01
The characteristics of 'Jovian' vortices (the large vortices observed in the atmospheres of Jupiter, Saturn, Neptune) are summarized, and the existence of similar structures in the atmospheres of stars is considered theoretically. The problem of vortex maintenance is addressed, including potential vorticity, numerical simulations of Jovian vortices, and cyclones and anticyclones; the Great Red Spot of Jupiter is described on the basis of Voyager data; the evidence for convective generation of vertical vorticity in the sun is examined; the possibly vortical nature of the large spots of RS CVn stars is discussed; and models of spots on rapidly rotating hot stars are surveyed. 62 refs.
Universal Topological Quantum Computation from a Superconductor-Abelian Quantum Hall Heterostructure
NASA Astrophysics Data System (ADS)
Mong, Roger S. K.; Clarke, David J.; Alicea, Jason; Lindner, Netanel H.; Fendley, Paul; Nayak, Chetan; Oreg, Yuval; Stern, Ady; Berg, Erez; Shtengel, Kirill; Fisher, Matthew P. A.
2014-01-01
Non-Abelian anyons promise to reveal spectacular features of quantum mechanics that could ultimately provide the foundation for a decoherence-free quantum computer. A key breakthrough in the pursuit of these exotic particles originated from Read and Green's observation that the Moore-Read quantum Hall state and a (relatively simple) two-dimensional p+ip superconductor both support so-called Ising non-Abelian anyons. Here, we establish a similar correspondence between the Z3 Read-Rezayi quantum Hall state and a novel two-dimensional superconductor in which charge-2e Cooper pairs are built from fractionalized quasiparticles. In particular, both phases harbor Fibonacci anyons that—unlike Ising anyons—allow for universal topological quantum computation solely through braiding. Using a variant of Teo and Kane's construction of non-Abelian phases from weakly coupled chains, we provide a blueprint for such a superconductor using Abelian quantum Hall states interlaced with an array of superconducting islands. Fibonacci anyons appear as neutral deconfined particles that lead to a twofold ground-state degeneracy on a torus. In contrast to a p+ip superconductor, vortices do not yield additional particle types, yet depending on nonuniversal energetics can serve as a trap for Fibonacci anyons. These results imply that one can, in principle, combine well-understood and widely available phases of matter to realize non-Abelian anyons with universal braid statistics. Numerous future directions are discussed, including speculations on alternative realizations with fewer experimental requirements.
NASA Astrophysics Data System (ADS)
Passarino, Giampiero
2014-05-01
Higgs Computed Axial Tomography, an excerpt. The Higgs boson lineshape ( and the devil hath power to assume a pleasing shape, Hamlet, Act II, scene 2) is analyzed for the process, with special emphasis on the off-shell tail which shows up for large values of the Higgs virtuality. The effect of including background and interference is also discussed. The main focus of this work is on residual theoretical uncertainties, discussing how much-improved constraint on the Higgs intrinsic width can be revealed by an improved approach to analysis.
Defining coherent vortices objectively from the vorticity
NASA Astrophysics Data System (ADS)
Haller, G.; Hadjighasem, A.; Farazmand, M.; Huhn, F.
2016-05-01
Rotationally coherent Lagrangian vortices are formed by tubes of deforming fluid elements that complete equal bulk material rotation relative to the mean rotation of the deforming fluid volume. We show that initial positions of such tubes coincide with tubular level surfaces of the Lagrangian-Averaged Vorticity Deviation (LAVD), the trajectory integral of the normed difference of the vorticity from its spatial mean. LAVD-based vortices are objective, i.e., remain unchanged under time-dependent rotations and translations of the coordinate frame. In the limit of vanishing Rossby numbers in geostrophic flows, cyclonic LAVD vortex centers are precisely the observed attractors for light particles. A similar result holds for heavy particles in anticyclonic LAVD vortices. We also establish a relationship between rotationally coherent Lagrangian vortices and their instantaneous Eulerian counterparts. The latter are formed by tubular surfaces of equal material rotation rate, objectively measured by the Instantaneous Vorticity Deviation (IVD). We illustrate the use of the LAVD and the IVD to detect rotationally coherent Lagrangian and Eulerian vortices objectively in several two- and three-dimensional flows.
Stable fractional vortices in the cyclic states of Bose-Einstein condensates
NASA Astrophysics Data System (ADS)
Huhtamäki, J. A. M.; Simula, T. P.; Kobayashi, M.; Machida, K.
2009-11-01
We propose methods to create fractional vortices in the cyclic state of an F=2 spinor Bose-Einstein condensate by manipulating its internal spin structure using pulsed microwave and laser fields. The stability of such vortices is studied as a function of the rotation frequency of the confining harmonic trap both in pancake- and cigar-shaped condensates. We find a range of parameters for which the so-called (1)/(3) vortex state is energetically favorable. Such fractional vortices could be created in condensates of R87b atoms using current experimental techniques facilitating probing of topological defects with non-Abelian statistics.
Matrix model for non-Abelian quantum Hall states
NASA Astrophysics Data System (ADS)
Dorey, Nick; Tong, David; Turner, Carl
2016-08-01
We propose a matrix quantum mechanics for a class of non-Abelian quantum Hall states. The model describes electrons which carry an internal SU(p ) spin. The ground states of the matrix model include spin-singlet generalizations of the Moore-Read and Read-Rezayi states and, in general, lie in a class previously introduced by Blok and Wen. The effective action for these states is a U(p ) Chern-Simons theory. We show how the matrix model can be derived from quantization of the vortices in this Chern-Simons theory and how the matrix model ground states can be reconstructed as correlation functions in the boundary WZW model.
Vortex operator and BKT transition in Abelian duality
NASA Astrophysics Data System (ADS)
Chern, Tong
2016-04-01
We give a new simple derivation for the sine-Gordon description of Berezinskii-Kosterlitz-Thouless (BKT) phase transition. Our derivation is simpler than traditional derivations. Besides, our derivation is a continuous field theoretic derivation by using path integration, different from the traditional derivations which are based on lattice theory or based on Coulomb gas model. Our new derivation relies on Abelian duality of two dimensional quantum field theory. By utilizing this duality in path integration, we find that the vortex configurations are naturally mapped to exponential operators in dual description. Since these operators are the vortex operators that can create vortices, the sine-Gordon description then naturally follows. Our method may be useful for the investigation to the BKT physics of superconductors.
Critical string from non-Abelian vortex in four dimensions
NASA Astrophysics Data System (ADS)
Shifman, M.; Yung, A.
2015-11-01
In a class of non-Abelian solitonic vortex strings supported in certain N = 2 super-Yang-Mills theories we search for the vortex which can behave as a critical fundamental string. We use the Polchinski-Strominger criterion of the ultraviolet completeness. We identify an appropriate four-dimensional bulk theory: it has the U (2) gauge group, the Fayet-Iliopoulos term and four flavor hypermultiplets. It supports semilocal vortices with the world-sheet theory for orientational (size) moduli described by the weighted CP (2 , 2) model. The latter is superconformal. Its target space is six-dimensional. The overall Virasoro central charge is critical. We show that the world-sheet theory on the vortex supported in this bulk model is the bona fide critical string.
Abelian and non-abelian D-brane effective actions
NASA Astrophysics Data System (ADS)
Koerber, P.
2004-09-01
In this Ph.D. thesis, accepted at the Vrije Universiteit Brussel, we review and elaborate on a method to find the D-brane effective action, based on BPS equations. Firstly, both for the Yang-Mills action and the Born-Infeld action it is shown that these configurations are indeed BPS, i.e. solutions to these equations saturate a Bogomolny bound and leave some supersymmetry unbroken. Next, we use the BPS equations as a tool to construct the D-brane effective action and require that (a deformation of) these equations should still imply the equations of motion in more general cases. In the abelian case we managed to calculate all order in four-derivative corrections to the effective action and the BPS equations while in the non-abelian case we obtained the effective action up to order 4. Furthermore, we discuss a check based on the spectrum of strings stretching between intersecting branes. Finally, this Ph.D. thesis also discusses the construction of a boundary superspace which would be the first step to use the method of Weyl invariance in N = 2 superspace in order to again construct the D-brane effective action. A more detailed summary of each section can be found in the introduction.
NASA Astrophysics Data System (ADS)
Gerbier, Fabrice; Goldman, Nathan; Lewenstein, Maciej; Sengstock, Klaus
2013-07-01
Building a universal quantum computer is a central goal of emerging quantum technologies, which has the potential to revolutionize science and technology. Unfortunately, this future does not seem to be very close at hand. However, quantum computers built for a special purpose, i.e. quantum simulators , are currently developed in many leading laboratories. Many schemes for quantum simulation have been proposed and realized using, e.g., ultracold atoms in optical lattices, ultracold trapped ions, atoms in arrays of cavities, atoms/ions in arrays of traps, quantum dots, photonic networks, or superconducting circuits. The progress in experimental implementations is more than spectacular. Particularly interesting are those systems that simulate quantum matter evolving in the presence of gauge fields. In the quantum simulation framework, the generated (synthetic) gauge fields may be Abelian, in which case they are the direct analogues of the vector potentials commonly associated with magnetic fields. In condensed matter physics, strong magnetic fields lead to a plethora of fascinating phenomena, among which the most paradigmatic is perhaps the quantum Hall effect. The standard Hall effect consists in the appearance of a transverse current, when a longitudinal voltage difference is applied to a conducting sample. For quasi-two-dimensional semiconductors at low temperatures placed in very strong magnetic fields, the transverse conductivity, the ratio between the transverse current and the applied voltage, exhibits perfect and robust quantization, independent for instance of the material or of its geometry. Such an integer quantum Hall effect, is now understood as a deep consequence of underlying topological order. Although such a system is an insulator in the bulk, it supports topologically robust edge excitations which carry the Hall current. The robustness of these chiral excitations against backscattering explains the universality of the quantum Hall effect. Another
NASA Astrophysics Data System (ADS)
Ortín, Tomás; Ramírez, Pedro F.
2016-09-01
We construct a supersymmetric black ring solution of SU (2) N = 1, d = 5 Super-Einstein-Yang-Mills (SEYM) theory by adding a distorted BPST instanton to an Abelian black ring solution of the same theory. The change cannot be observed from spatial infinity: neither the mass, nor the angular momenta or the values of the scalars at infinity differ from those of the Abelian ring. The entropy is, however, sensitive to the presence of the non-Abelian instanton, and it is smaller than that of the Abelian ring, in analogy to what happens in the supersymmetric colored black holes recently constructed in the same theory and in N = 2, d = 4 SEYM. By taking the limit in which the two angular momenta become equal we derive a non-Abelian generalization of the BMPV rotating black-hole solution.
Observation of the Meissner effect in a lattice Higgs model
NASA Technical Reports Server (NTRS)
Damgaard, Poul H.; Heller, Urs M.
1988-01-01
The lattice-regularized U(1) Higgs model in an external electromagnetic field is studied by Monte Carlo techniques. In the Coulomb phase, magnetic flux can flow through uniformly. The Higgs phase splits into a region where magnetic flux can penetrate only in the form of vortices and a region where the magnetic flux is completely expelled, the relativistic analog of the Meissner effect in superconductivity. Evidence is presented for symmetry restoration in strong external fields.
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; Sexty, Dénes
2014-07-28
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; Sexty, Dénes
2014-07-28
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixedmore » point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.« less
Annihilation of strained vortices
NASA Astrophysics Data System (ADS)
Kimura, Yoshifumi
2014-11-01
As an initial stage of vortex reconnection, approach of nearly anti-parallel vortices has often been observed experimentally and studied numerically. Inspired by the recent experiment by Kleckner and Irvine on the dynamics of knotted vortices, we have studied the motion of two anti-parellel Burgers vortices driven by an axisymmetric linear straining field. We first extend the Burgers vortex solution which is a steady exact solution of the Navier-Stokes equation to a time-dependent exact solution. Then by superposing two such solutions, we investigate the annihilation process analytically. We can demonstrate that during the annihilation process the total vorticity decays exponentially on a time-scale proportional to the inverse of the rate of strain, even as the kinematic viscosity tends to 0. The analytic results are compared with the numerical simulations of two strained vortices with the vortex-vortex nonlinear interaction by Buntine and Pullin.
NASA Astrophysics Data System (ADS)
Gerbier, Fabrice; Goldman, Nathan; Lewenstein, Maciej; Sengstock, Klaus
2013-07-01
Building a universal quantum computer is a central goal of emerging quantum technologies, which has the potential to revolutionize science and technology. Unfortunately, this future does not seem to be very close at hand. However, quantum computers built for a special purpose, i.e. quantum simulators , are currently developed in many leading laboratories. Many schemes for quantum simulation have been proposed and realized using, e.g., ultracold atoms in optical lattices, ultracold trapped ions, atoms in arrays of cavities, atoms/ions in arrays of traps, quantum dots, photonic networks, or superconducting circuits. The progress in experimental implementations is more than spectacular. Particularly interesting are those systems that simulate quantum matter evolving in the presence of gauge fields. In the quantum simulation framework, the generated (synthetic) gauge fields may be Abelian, in which case they are the direct analogues of the vector potentials commonly associated with magnetic fields. In condensed matter physics, strong magnetic fields lead to a plethora of fascinating phenomena, among which the most paradigmatic is perhaps the quantum Hall effect. The standard Hall effect consists in the appearance of a transverse current, when a longitudinal voltage difference is applied to a conducting sample. For quasi-two-dimensional semiconductors at low temperatures placed in very strong magnetic fields, the transverse conductivity, the ratio between the transverse current and the applied voltage, exhibits perfect and robust quantization, independent for instance of the material or of its geometry. Such an integer quantum Hall effect, is now understood as a deep consequence of underlying topological order. Although such a system is an insulator in the bulk, it supports topologically robust edge excitations which carry the Hall current. The robustness of these chiral excitations against backscattering explains the universality of the quantum Hall effect. Another
Abelian link invariants and homology
Guadagnini, Enore; Mancarella, Francesco
2010-06-15
We consider the link invariants defined by the quantum Chern-Simons field theory with compact gauge group U(1) in a closed oriented 3-manifold M. The relation of the Abelian link invariants with the homology group of the complement of the links is discussed. We prove that, when M is a homology sphere or when a link--in a generic manifold M--is homologically trivial, the associated observables coincide with the observables of the sphere S{sup 3}. Finally, we show that the U(1) Reshetikhin-Turaev surgery invariant of the manifold M is not a function of the homology group only, nor a function of the homotopy type of M alone.
Optical Abelian lattice gauge theories
Tagliacozzo, L.; Celi, A.; Zamora, A.; Lewenstein, M.
2013-03-15
We discuss a general framework for the realization of a family of Abelian lattice gauge theories, i.e., link models or gauge magnets, in optical lattices. We analyze the properties of these models that make them suitable for quantum simulations. Within this class, we study in detail the phases of a U(1)-invariant lattice gauge theory in 2+1 dimensions, originally proposed by P. Orland. By using exact diagonalization, we extract the low-energy states for small lattices, up to 4 Multiplication-Sign 4. We confirm that the model has two phases, with the confined entangled one characterized by strings wrapping around the whole lattice. We explain how to study larger lattices by using either tensor network techniques or digital quantum simulations with Rydberg atoms loaded in optical lattices, where we discuss in detail a protocol for the preparation of the ground-state. We propose two key experimental tests that can be used as smoking gun of the proper implementation of a gauge theory in optical lattices. These tests consist in verifying the absence of spontaneous (gauge) symmetry breaking of the ground-state and the presence of charge confinement. We also comment on the relation between standard compact U(1) lattice gauge theory and the model considered in this paper. - Highlights: Black-Right-Pointing-Pointer We study the quantum simulation of dynamical gauge theories in optical lattices. Black-Right-Pointing-Pointer We focus on digital simulation of abelian lattice gauge theory. Black-Right-Pointing-Pointer We rediscover and discuss the puzzling phase diagram of gauge magnets. Black-Right-Pointing-Pointer We detail the protocol for time evolution and ground-state preparation in any phase. Black-Right-Pointing-Pointer We provide two experimental tests to validate gauge theory quantum simulators.
Bardeen, William A.; /Fermilab
2008-05-01
I discuss the Standard Model of Elementary Particle Physics and potential for discoveries of the physics responsible for electroweak symmetry breaking. I review the ideas leading to development of the Brout-Englert-Higgs mechanism that now forms the basis for the conventional Standard Model. I discuss various issues that challenge application of the Standard Model to the known physics of elementary particles. I examine alternatives to the Standard Model that address these issues and may lead to new discoveries at the LHC that go Beyond Higgs.
Abelian and non-Abelian bosonization: The operator solution of the WZW. sigma. model
do Amaral, R.L.P.G. ); Stephany Ruiz, J.E. )
1991-03-15
The complete equivalence between the Abelian and the non-Abelian bosonization formalisms for the treatment of SU({ital N}) fermions in two dimensions is analyzed and the operator solution of the Wess-Zumino-Witten nonlinear {sigma} model, written in terms of the scalar fields of the non-Abelian construction, is obtained. The importance of the order and disorder operators is stressed. In particular, they are used to show that an adequate reinterpretation of Mandelstam's formula gives the fermion representation in the non-Abelian bosonization formalism.
NASA Technical Reports Server (NTRS)
Holmes, Bruce J. (Inventor); Carraway, Debra L. (Inventor); Holmes, Harlan K. (Inventor); Moore, Thomas C. (Inventor)
1988-01-01
A crossflow vorticity sensor for the detection of crossflow vorticity characteristics is described. The sensor is comprised of crossflow sensors which are noninvasively adhered to a swept wing laminar surface either singularly, in multi-element strips, in polar patterns, or in orthogonal patterns. These crossflow sensors are comprised of hot-film sensor elements which operate as a constant temperature anemometer circuit to detect heat transfer rate changes. Accordingly, crossflow vorticity characteristics are determined via cross-correlation. In addition, the crossflow sensors have a thickness which does not exceed a maximum value h in order to avoid contamination of downstream crossflow sensors.
The distribution of vorticity in a large vortical motion
NASA Technical Reports Server (NTRS)
Disimile, Peter J.
1988-01-01
An experimental investigation into the distribution of vorticity in the large scale vortical motions which are found in free shear layers was undertaken. Using hot-wire anemometry, both quasi-instantaneous and phase averaged transverse vorticity were acquired. These results appear to indicate that the transverse vorticity in a large scale vortical motion is distributed in a marble cake manner and not in laminated sheets spooled up into a coil or helical spring. Also, levels of vorticity were found to vary by as much as an order of magnitude in these concentrated vortical cores.
ERIC Educational Resources Information Center
Veltman, Martinus J. G.
1986-01-01
Reports recent findings related to the particle Higgs boson and examines its possible contribution to the standard mode of elementary processes. Critically explores the strengths and uncertainties of the Higgs boson and proposed Higgs field. (ML)
On whole Abelian model dynamics
Chauca, J.; Doria, R.
2012-09-24
Physics challenge is to determine the objects dynamics. However, there are two ways for deciphering the part. The first one is to search for the ultimate constituents; the second one is to understand its behaviour in whole terms. Therefore, the parts can be defined either from elementary constituents or as whole functions. Historically, science has been moving through the first aspect, however, quarks confinement and complexity are interrupting this usual approach. These relevant facts are supporting for a systemic vision be introduced. Our effort here is to study on the whole meaning through gauge theory. Consider a systemic dynamics oriented through the U(1) - systemic gauge parameter which function is to collect a fields set {l_brace}A{sub {mu}I}{r_brace}. Derive the corresponding whole gauge invariant Lagrangian, equations of motion, Bianchi identities, Noether relationships, charges and Ward-Takahashi equations. Whole Lorentz force and BRST symmetry are also studied. These expressions bring new interpretations further than the usual abelian model. They are generating a systemic system governed by 2N+ 10 classical equations plus Ward-Takahashi identities. A whole dynamics based on the notions of directive and circumstance is producing a set determinism where the parts dynamics are inserted in the whole evolution. A dynamics based on state, collective and individual equations with a systemic interdependence.
Vortex dynamics in self-dual Chern-Simons-Higgs systems
Kim, Y. ); Lee, K. )
1994-02-15
We consider vortex dynamics in self-dual Chern-Simons-Higgs systems. We show that the naive Aharonov-Bohm phase is the inverse of the statistical phase expected from the vortex spin, and that the self-dual configurations of vortices are degenerate in energy but not in angular momentum. We also use the path integral formalism to derive the dual formulation of Chern-Simons-Higgs systems in which vortices appear as charged particles. We argue that in addition to the electromagnetic interaction, there is an additional interaction between vortices, the so-called Magnus force, and that these forces can be put together into a single dual electromagnetic'' interaction. This dual electromagnetic interaction leads to the right statistical phase. We also derive and study the effective action for slowly moving vortices, which contains terms both linear and quadratic in the vortex velocity. We show that vortices can be bounded to each other by the Magnus force.
S-duality in SU(3) Yang-Mills theory with non-abelian unbroken gauge group
NASA Astrophysics Data System (ADS)
Schroers, B. J.; Bais, F. A.
1998-12-01
It is observed that the magnetic charges of classical monopole solutions in Yang-Mills-Higgs theory with non-abelian unbroken gauge group H are in one-to-one correspondence with coherent states of a dual or magnetic group H˜. In the spirit of the Goddard-Nuyts-Olive conjecture this observation is interpreted as evidence for a hidden magnetic symmetry of Yang-Mills theory. SU(3) Yang-Mills-Higgs theory with unbroken gauge group U(2) is studied in detail. The action of the magnetic group on semi-classical states is given explicitly. Investigations of dyonic excitations show that electric and magnetic symmetry are never manifest at the same time: Non-abelian magnetic charge obstructs the realisation of electric symmetry and vice-versa. On the basis of this fact the charge sectors in the theory are classified and their fusion rules are discussed. Non-abelian electric-magnetic duality is formulated as a map between charge sectors. Coherent states obey particularly simple fusion rules, and in the set of coherent states S-duality can be formulated as an SL(2, Z) mapping between sectors which leaves the fusion rules invariant.
Macek, Joseph H ORNL
2012-01-01
The time-dependent Schrodinger equation describes dynamical processes of one-electron species in terms of a complex wave function. The function is inherently complex, therefore zeros occur only when both the real and imaginary parts of the wave function vanish. If this happens at isolated points rather than on a nodal surface one can show the zero must correspond to a vortex. An imaging theorem is given which shows how such vortices can be seen experimentally. Since the theorem requires time propagation from microscopic to macroscopic scales, a method is developed that does just that. Examples of vortices that emerge in dynamical processes are given. The vortices that we nd are linked to the hydrodynamic interpretation of Schrodinger's time-dependent equation.
Relaminarization under stationary vortices
NASA Astrophysics Data System (ADS)
Breidenthal, Robert
2005-11-01
Flow visualization reveals that a turbulent boundary layer is relaminarized when stationary streamwise vortices are introduced. Following a suggestion of Balle, the vortices are stabilized by large streamwise ``Karman'' grooves in a wavy wall. In a water tunnel, upstream vortex generators place a large streamwise vortex in the middle of each groove, at the stationary point where Prandtl's vortex force vanishes. According to a theory by Cotel, the wall fluxes of a turbulent boundary layer should decline to laminar values under such ``persistent'' vortices. The observed relaminarization is consistent with this theory and with previous measurements of heat transfer by Touel and Balle. However, the structure of the transverse flow resembles the cats-eye pattern of a temporal shear layer rather than the anticipated von Karman wake. The cats-eye pattern corresponds to the forced shear layers of Oster-Wygnanski and Roberts, who found that the Reynolds stresses and mixing rate also decline to laminar values.
Abelian 3-form gauge theory: Superfield approach
NASA Astrophysics Data System (ADS)
Malik, R. P.
2012-09-01
We discuss a D-dimensional Abelian 3-form gauge theory within the framework of Bonora-Tonin's superfield formalism and derive the off-shell nilpotent and absolutely anticommuting Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for this theory. To pay our homage to Victor I. Ogievetsky (1928-1996), who was one of the inventors of Abelian 2-form (antisymmetric tensor) gauge field, we go a step further and discuss the above D-dimensional Abelian 3-form gauge theory within the framework of BRST formalism and establish that the existence of the (anti-)BRST invariant Curci-Ferrari (CF) type of restrictions is the hallmark of any arbitrary p-form gauge theory (discussed within the framework of BRST formalism).
NASA Astrophysics Data System (ADS)
Iadecola, Thomas; Schuster, Thomas; Chamon, Claudio
2016-08-01
Many topological phenomena first proposed and observed in the context of electrons in solids have recently found counterparts in photonic and acoustic systems. In this work, we demonstrate that non-Abelian Berry phases can arise when coherent states of light are injected into "topological guided modes" in specially fabricated photonic waveguide arrays. These modes are photonic analogues of topological zero modes in electronic systems. Light traveling inside spatially well-separated topological guided modes can be braided, leading to the accumulation of non-Abelian phases, which depend on the order in which the guided beams are wound around one another. Notably, these effects survive the limit of large photon occupation, and can thus also be understood as wave phenomena arising directly from Maxwell's equations, without resorting to the quantization of light. We propose an optical interference experiment as a direct probe of this non-Abelian braiding of light.
Non-Abelian Braiding of Light.
Iadecola, Thomas; Schuster, Thomas; Chamon, Claudio
2016-08-12
Many topological phenomena first proposed and observed in the context of electrons in solids have recently found counterparts in photonic and acoustic systems. In this work, we demonstrate that non-Abelian Berry phases can arise when coherent states of light are injected into "topological guided modes" in specially fabricated photonic waveguide arrays. These modes are photonic analogues of topological zero modes in electronic systems. Light traveling inside spatially well-separated topological guided modes can be braided, leading to the accumulation of non-Abelian phases, which depend on the order in which the guided beams are wound around one another. Notably, these effects survive the limit of large photon occupation, and can thus also be understood as wave phenomena arising directly from Maxwell's equations, without resorting to the quantization of light. We propose an optical interference experiment as a direct probe of this non-Abelian braiding of light. PMID:27563965
NASA Astrophysics Data System (ADS)
Olson Reichhardt, C. J.; Hastings, M. B.
2004-04-01
We propose an experiment for directly constructing and locally probing topologically entangled states of superconducting vortices which can be performed with present-day technology. Calculations using an elastic string vortex model indicate that as the pitch (the winding angle divided by the vertical distance) increases, the vortices approach each other. At values of the pitch higher than a maximum value the entangled state becomes unstable to collapse via a singularity of the model. We provide predicted experimental signatures for both vortex entanglement and vortex cutting. The local probe we propose can also be used to explore a wide range of other quantities.
Decay of the standard model Higgs field after inflation
NASA Astrophysics Data System (ADS)
Figueroa, Daniel G.; García-Bellido, Juan; Torrentí, Francisco
2015-10-01
We study the nonperturbative dynamics of the standard model (SM) after inflation, in the regime where the SM is decoupled from (or weakly coupled to) the inflationary sector. We use classical lattice simulations in an expanding box in (3 +1 ) dimensions, modeling the SM gauge interactions with both global and Abelian-Higgs analogue scenarios. We consider different postinflationary expansion rates. During inflation, the Higgs forms a condensate, which starts oscillating soon after inflation ends. Via nonperturbative effects, the oscillations lead to a fast decay of the Higgs into the SM species, transferring most of the energy into Z and W± bosons. All species are initially excited far away from equilibrium, but their interactions lead them into a stationary stage, with exact equipartition among the different energy components. From there on, the system eventually reaches equilibrium. We have characterized in detail, in the different expansion histories considered, the evolution of the Higgs and of its dominant decay products until equipartition is established. We provide a useful mapping between simulations with different parameters, from which we derive a master formula for the Higgs decay time as a function of the coupling constants, Higgs initial amplitude and postinflationary expansion rate.
Continuously tailored Taylor vortices
NASA Astrophysics Data System (ADS)
Sprague, M. A.; Weidman, P. D.
2009-11-01
Modified axisymmetric, finite-length Taylor-Couette (TC) cells with stationary outer cylinder and rotating inner cylinder are designed in an effort to produce simultaneous onset of toroidal vortices of continuously varying wavelength along the gap. For a given axial variation in the inner radius, the axial variation in the outer radius can be chosen such that at every axial position, the criterion for the onset of Taylor vortices in a corresponding classical TC cell is met. In one scenario, a conical inner cylinder is chosen and the shape of the outer cylinder is then determined by locally satisfying the onset criterion. In another scenario, the inner and outer radii are chosen such that the onset criterion is locally satisfied and the axial rate of change in the classical onset wave number is held constant. In both cases, the modified cells possess a large-scale meridional circulation wrought by the finite Ekman (Bödewadt) pumping on the inner (outer) cylinder walls. Using direct numerical simulation, it is found that for sufficiently large aspect ratio, there exists a critical rotation rate for the simultaneous transition from the base flow to counter-rotating toroidal vortices throughout the varying-radius region. The vortices propagate in the direction of decreasing gap width with a phase speed that decreases with increasing aspect ratio.
Multiflavor QCD* on R_3 * S_1: Studying Transition From Abelian to Non-Abelian Confinement
Shifman, M.; Unsal, M.; /SLAC /Stanford U., Phys. Dept.
2009-03-31
The center-stabilized multiflavor QCD* theories formulated on R{sub 3} x S{sub 1} exhibit both Abelian and non-Abelian confinement as a function of the S{sub 1} radius, similar to the Seiberg-Witten theory as a function of the mass deformation parameter. For sufficiently small number of flavors and small r(S{sub 1}), we show occurrence of a mass gap in gauge fluctuations, and linear confinement. This is a regime of confinement without continuous chiral symmetry breaking ({chi}SB). Unlike one-flavor theories where there is no phase transition in r(S{sub 1}), the multiflavor theories possess a single phase transition associated with breaking of the continuous {chi}S. We conjecture that the scale of the {chi}SB is parametrically tied up with the scale of Abelian to non-Abelian confinement transition.
Vorticity production in shock diffraction
NASA Astrophysics Data System (ADS)
Sun, M.; Takayama, K.
2003-03-01
The production of vorticity or circulation production in shock wave diffraction over sharp convex corners has been numerically simulated and quantified. The corner angle is varied from 5° to 180°. Total vorticity is represented by the circulation, which is evaluated by integrating the velocity along a path enclosing the perturbed region behind a diffracting shock wave. The increase of circulation in unit time, or the rate of circulation production, depends on the shock strength and wall angle if the effects of viscosity and heat conductivity are neglected. The rate of vorticity production is determined by using a solution-adaptive code, which solves the Euler equations. It is shown that the rate of vorticity production is independent of the computational mesh and numerical scheme by comparing solutions from two different codes. It is found that larger wall angles always enhance the vorticity production. The vorticity production increases sharply when the corner angle is varied from 15° to 45°. However, for corner angles over 90°, the rate of vorticity production hardly increases and reaches to a constant value. Strong shock waves produce vorticity faster in general, except when the slipstream originating from the shallow corner attaches to the downstream wall. It is found that the vorticity produced by the slipstream represents a large proportion of the total vorticity. The slipstream is therefore a more important source of vorticity than baroclinic effects in shock diffraction.
NASA Astrophysics Data System (ADS)
Sprague, M. A.; Weidman, P. D.; Macumber, S.; Fischer, P. F.
2008-01-01
The stability of circular Couette flow in discontinuous axisymmetric geometries is investigated using numerical simulations and physical experiments. By contouring the geometry of the inner cylinder, Taylor vortices can be made to appear in discrete sections along the length of the cylinder while adjoining sections remain stable. The disparate flows are connected by transition regions that arise from the stability of the axially nonuniform base flow state. The geometry of the inner cylinder can be tailored to produce the simultaneous onset of Taylor vortices of different wavelength in neighboring sections. In another variant, a stack of inner cylinders of common radius are made to rotate independently to produce adjacent regions of stable and unstable flow.
Toward modeling wingtip vortices
NASA Technical Reports Server (NTRS)
Zeman, O.
1993-01-01
Wingtip vortices are generated by lifting airfoils; their salient features are compactness and relatively slow rate of decay. The principal motivation for studying the far field evolution of wingtip vortices is the need to understand and predict the extent of the vortex influence during aircraft take-off or landing. On submarines a wingtip vortex ingested into a propeller can be a source of undesirable noise. The main objectives of this research are (1) to establish theoretical understanding of the principal mechanisms that govern the later (diffusive) stages of a turbulent vortex, (2) to develop a turbulence closure model representing the basic physical mechanisms that control the vortex diffusive stage, and further (3) to investigate coupling between the near and far field evolutions; in other words, to study the effect of initial conditions on the vortex lifetime and the ultimate state.
NASA Astrophysics Data System (ADS)
Cropp, Bethan; Liberati, Stefano; Turcati, Rodrigo
2016-06-01
In the analog gravity framework, the acoustic disturbances in a moving fluid can be described by an equation of motion identical to a relativistic scalar massless field propagating in curved space-time. This description is possible only when the fluid under consideration is barotropic, inviscid, and irrotational. In this case, the propagation of the perturbations is governed by an acoustic metric that depends algebrically on the local speed of sound, density, and the background flow velocity, the latter assumed to be vorticity-free. In this work we provide a straightforward extension in order to go beyond the irrotational constraint. Using a charged—relativistic and nonrelativistic—Bose–Einstein condensate as a physical system, we show that in the low-momentum limit and performing the eikonal approximation we can derive a d’Alembertian equation of motion for the charged phonons where the emergent acoustic metric depends on flow velocity in the presence of vorticity.
Untangling Superfluid Vortices
NASA Astrophysics Data System (ADS)
Kleckner, Dustin; Scheeler, Martin W.; Proment, Davide; Irvine, William T. M.
2015-03-01
What is the role of topology, or knottedness, in superfluid phase defects (quantum vortices)? In ideal classical fluids, vortex knots may never untie, and so there is an associated conserved quantity - helicity - which measures how tangled a flow is. One might expect a similar robustness for superfluid defects, however, simulations of the Gross-Pitevskii equation demonstrate that vortex knots and links spontaneously untie and unlink. Nonetheless, the topology dramatically affects the vortex evolution, and a component of the initial helicity is transferred to helical coils as the knots unravel. These effects are remarkably similar to the behavior of tangled vortices in viscous fluids, suggesting they are universal features of non-ideal fluids.
NASA Technical Reports Server (NTRS)
Perry, A. E.; Chong, M. S.; Lim, T. T.
1982-01-01
Theoretical and experimental results of studies to determine the flow parameters and structures of plane mixing layers are reported. Smoke visualization, combined with hot-wire anemometry, sheets of laser light, and photography were used to gather data from the wall flow. The behavior of vortex rods was examined, noting that the rods persisted only if new vortex energy was supplied from the sublayer. A power spectral density was defined for the velocity fluctuations, as was a hierarchy of velocity scales for geometrically similar vortices. The length scale grows linearly with downstream distance, where the flow structures are fed by longitudinal vortices. A model is developed for vortex pairing in sequential order from the bottom of the mixing layer outward in a repetitive process involving vortex stretching. The model is actually a migration strategy that satisfies the flow self-preservation constraints.
Axisymmetric Vortices with Swirl
NASA Astrophysics Data System (ADS)
Elcrat, A.
2007-11-01
This talk is concerned with finding solutions of the Euler equations by solving elliptic boundary value problems for the Bragg-Hawthorne equation L u= -urr -(1/r)ur - = r^2f (u) + h(u). Theoretical results have been given for previously (Elcrat and Miller, Differential and Integral Equations 16(4) 2003, 949-968) for problems with swirl and general classes of profile functions f, h by iterating Lu(n+1)= rf(u)n)) + h(u(n)), and showing u(n) converges montonically to a solution. The solutions obtained depend on the initial guess, which can be thought of as prescribing level sets of the vortex. When a computational program was attempted these monotone iterations turned out to be numerically unstable, and a stable computation was acheived by fixing the moment of the cross section of a vortex in the merideanal plane. (This generalizes previous computational results in Elcrat, Fornberg and Miller, JFM 433 2001, (315-328) We obtain famillies of vortices related to vortex rings with swirl, Moffatt's generalization of Hill's vortex and tubes of vorticity with swirl wrapped around the symmetry axis. The vortices are embedded in either an irrotational flow or a flow with shear, and we deal with the transition form no swirl in the vortex to flow with only swirl, a Beltrami flow.
Vorticity in the solar photosphere
NASA Astrophysics Data System (ADS)
Shelyag, S.; Keys, P.; Mathioudakis, M.; Keenan, F. P.
2011-02-01
Aims: We use magnetic and non-magnetic 3D numerical simulations of solar granulation and G-band radiative diagnostics from the resulting models to analyse the generation of small-scale vortex motions in the solar photosphere. Methods: Radiative MHD simulations of magnetoconvection are used to produce photospheric models. Our starting point is a non-magnetic model of solar convection, where we introduce a uniform magnetic field and follow the evolution of the field in the simulated photosphere. We find two different types of photospheric vortices, and provide a link between the vorticity generation and the presence of the intergranular magnetic field. A detailed analysis of the vorticity equation, combined with the G-band radiative diagnostics, allows us to identify the sources and observational signatures of photospheric vorticity in the simulated photosphere. Results: Two different types of photospheric vorticity, magnetic and non-magnetic, are generated in the domain. Non-magnetic vortices are generated by the baroclinic motions of the plasma in the photosphere, while magnetic vortices are produced by the magnetic tension in the intergranular magnetic flux concentrations. The two types of vortices have different shapes. We find that the vorticity is generated more efficiently in the magnetised model. Simulated G-band images show a direct connection between magnetic vortices and rotary motions of photospheric bright points, and suggest that there may be a connection between the magnetic bright point rotation and small-scale swirl motions observed higher in the atmosphere.
Abelian and non-Abelian states in ν = 2 / 3 bilayer fractional quantum Hall systems
NASA Astrophysics Data System (ADS)
Peterson, Michael; Wu, Yang-Le; Cheng, Meng; Barkeshli, Maissam; Wang, Zhenghan
There are several possible theoretically allowed non-Abelian fractional quantum Hall (FQH) states that could potentially be realized in one- and two-component FQH systems at total filling fraction ν = n + 2 / 3 , for integer n. Some of these states even possess quasiparticles with non-Abelian statistics that are powerful enough for universal topological quantum computation, and are thus of particular interest. Here we initiate a systematic numerical study, using both exact diagonalization and variational Monte Carlo, to investigate the phase diagram of FQH systems at total filling fraction ν = n + 2 / 3 , including in particular the possibility of the non-Abelian Z4 parafermion state. In ν = 2 / 3 bilayers we determine the phase diagram as a function of interlayer tunneling and repulsion, finding only three competing Abelian states, without the Z4 state. On the other hand, in single-component systems at ν = 8 / 3 , we find that the Z4 parafermion state has significantly higher overlap with the exact ground state than the Laughlin state, together with a larger gap, suggesting that the experimentally observed ν = 8 / 3 state may be non-Abelian. Our results from the two complementary numerical techniques agree well with each other qualitatively. We acknowledge the Office of Research and Sponsored Programs at California State University Long Beach and Microsoft Station Q.
Anomalous Abelian symmetry in the standard model
Ramond, P.
1995-12-31
The observed hierarchy of quark and lepton masses can be parametrized by nonrenormalizable operators with dimensions determined by an anomalous Abelian family symmetry, a gauge extension to the minimal supersymmetric standard model. Such an Abelian symmetry is generic to compactified superstring theories, with its anomalies compensated by the Green-Schwarz mechanism. If we assume these two symmetries to be the same, we find the electroweak mixing angle to be sin {sup 2}{theta}{sub {omega}} = 3/8 at the string scale, just by setting the ratio of the product of down quark to charged lepton masses equal to one at the string scale. This assumes no GUT structure. The generality of the result suggests a superstring origin for the standard model. We generalize our analysis to massive neutrinos, and mixings in the lepton sector.
Interaction of Atmospheric Plasma Vortices
NASA Astrophysics Data System (ADS)
Izhovkina, N. I.; Artekha, S. N.; Erokhin, N. S.; Mikhailovskaya, L. A.
2016-06-01
Atmospheric electric fields, connected with the ionization of particles and plasma processes, occur in the fields of pressure gradients of mosaic mesh topology. Atmospheric aerosol particles play a significant role in the vortex generation. The Coriolis force and the motion of charged particles in the geomagnetic field lead to gyrotropy of the atmosphere and ionosphere. Occurrence of plasma vortices is stochastically determined for such an inhomogeneous gyrotropic medium. The geomagnetic field influences the change of structures of inhomogeneous media in the process of excitation of plasma vortices and their interaction. If colliding vortices are centered on the one geomagnetic line, the merge of vortices and the generation of a joint powerful vortex are possible. If a collision of vortices with centers at different geomagnetic field lines occurs, then the emergence of areas of heating and jet streams and the generation of new vortices are possible.
Interaction of Atmospheric Plasma Vortices
NASA Astrophysics Data System (ADS)
Izhovkina, N. I.; Artekha, S. N.; Erokhin, N. S.; Mikhailovskaya, L. A.
2016-08-01
Atmospheric electric fields, connected with the ionization of particles and plasma processes, occur in the fields of pressure gradients of mosaic mesh topology. Atmospheric aerosol particles play a significant role in the vortex generation. The Coriolis force and the motion of charged particles in the geomagnetic field lead to gyrotropy of the atmosphere and ionosphere. Occurrence of plasma vortices is stochastically determined for such an inhomogeneous gyrotropic medium. The geomagnetic field influences the change of structures of inhomogeneous media in the process of excitation of plasma vortices and their interaction. If colliding vortices are centered on the one geomagnetic line, the merge of vortices and the generation of a joint powerful vortex are possible. If a collision of vortices with centers at different geomagnetic field lines occurs, then the emergence of areas of heating and jet streams and the generation of new vortices are possible.
Low energy dynamics of slender monopoles in non-Abelian superconductor
NASA Astrophysics Data System (ADS)
Arai, M.; Blaschke, F.; Eto, M.; Sakai, N.
2016-01-01
Low energy dynamics of magnetic monopoles and anti-monopoles in the U(2)c gauge theory is studied in the Higgs (non-Abelian superconducting) phase. The monopoles in this phase are slender ellipsoids, pierced by a vortex string. We investigate scattering of monopole with anti-monopole and find that they do not always decay into radiation, contrary to our naive intuition. They can repel, make bound states (magnetic mesons) or resonances. We point out that some part of solutions in 1 + 3 dimensions can be mapped exactly onto the sine-Gordon system in 1 + 1 dimensions in the first non-trivial order of rigid-body approximation and we provide analytic formulas for such solutions there.
Geller, Michael; Telem, Ofri
2015-05-15
We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider. PMID:26024160
Photon collider Higgs factories
NASA Astrophysics Data System (ADS)
Telnov, V. I.
2014-09-01
The discovery of the Higgs boson (and still nothing else) have triggered appearance of many proposals of Higgs factories for precision measurement of the Higgs properties. Among them there are several projects of photon colliders (PC) without e+e- in addition to PLC based on e+e- linear colliders ILC and CLIC. In this paper, following a brief discussion of Higgs factories physics program I give an overview of photon colliders based on linear colliders ILC and CLIC, and of the recently proposed photon-collider Higgs factories with no e+e- collision option based on recirculation linacs in ring tunnels.
Defining and Computing Vortices Objectively from the Vorticity
NASA Astrophysics Data System (ADS)
Haller, George; Hadjighasem, Alireza; Farazmand, Mohammad; Huhn, Florian
2015-11-01
We introduce the notion of rotationally coherent Lagrangian vortices as tubular material surfaces in which fluid elements complete equal bulk material rotation relative to the mean rotation of the fluid. We find that initial positions of such tubes coincide with tubular level surfaces of the Lagrangian-Averaged Vorticity Deviation (LAVD), the trajectory integral of the normed difference of the vorticity from its spatial mean. LAVD-based vortices turn out to be objective, i.e., invariant under time-dependent rotations and translations of the reference frame. In the limit of vanishing Rossby numbers in geostrophic flows, cyclonic LAVD vortex centers can be proven to coincide with the observed attractors for light particles. A similar result holds for heavy particles in anticyclonic LAVD vortices. We also discuss a relationship between rotationally coherent Lagrangian vortices and their instantaneous Eulerian counterparts. The latter are formed by tubular surfaces of equal material rotation rate, objectively measured by the Instantaneous Vorticity Deviation (IVD). We show how the LAVD and the IVD detect rotationally coherent Lagrangian and Eulerian vortices objectively in analytic flow models and numerical flow data.
NASA Technical Reports Server (NTRS)
Greenblatt, David
2005-01-01
A wind tunnel investigation was carried out on a semi-span wing model to assess the feasibility of controlling vortices emanating from outboard flaps and tip-flaps by actively varying the degree of boundary layer separation. Separation was varied by means of perturbations produced from segmented zero-efflux oscillatory blowing slots, while estimates of span loadings and vortex sheet strengths were obtained by integrating wing surface pressures. These estimates were used as input to inviscid rollup relations as a means of predicting changes to the vortex characteristics resulting from the perturbations. Surveys of flow in the wake of the outboard and tip-flaps were made using a seven-hole probe, from which the vortex characteristics were directly deduced. Varying the degree of separation had a marked effect on vortex location, strength, tangential velocity, axial velocity and size for both outboard and tip-flaps. Qualitative changes in vortex characteristics were well predicted by the inviscid rollup relations, while the failure to account for viscosity was presumed to be the main reason for observed discrepancies. Introducing perturbations near the outboard flap-edges or on the tip-flap exerted significant control over vortices while producing negligible lift excursions.
Abelian gauge symmetries and proton decay in global F-theory GUTs
Grimm, Thomas W.; Weigand, Timo
2010-10-15
The existence of Abelian gauge symmetries in four-dimensional F-theory compactifications depends on the global geometry of the internal Calabi-Yau four-fold and has important phenomenological consequences. We study conceptual and phenomenological aspects of such U(1) symmetries along the Coulomb and the Higgs branch. As one application we examine Abelian gauge factors arising after a certain global restriction of the Tate model that goes beyond a local spectral cover analysis. In SU(5) grand unified theory (GUT) models this mechanism enforces a global U(1){sub X} symmetry that prevents dimension-4 proton decay and allows for an identification of candidate right-handed neutrinos. We invoke a detailed account of the singularities of Calabi-Yau four-folds and their mirror duals starting from an underlying E{sub 8} and E{sub 7}xU(1) enhanced Tate model. The global resolutions and deformations of these singularities can be used as the appropriate framework to analyze F-theory GUT models.
Yang-Mills Gauge Theory and Higgs Particle
NASA Astrophysics Data System (ADS)
Wu, Tai Tsun; Wu, Sau Lan
Motivated by the experimental data on the Higgs particle from the ATLAS Collaboration and the CMS Collaboration at CERN, the standard model, which is a Yang-Mills non-Abelian gauge theory with the group U(1) × SU (2) × SU (3), is augmented by scalar quarks and scalar leptons without changing the gauge group and without any additional Higgs particle. Thus there is fermion-boson symmetry between these new particles and the known quarks and leptons. In a simplest scenario, the cancellation of the quadratic divergences in this augmented standard model leads to a determination of the masses of all these scalar quarks and scalar leptons. All these masses are found to be less than 100 GeV/c2, and the right-handed scalar neutrinos are especially light. Alterative procedures are given with less reliance on the experimental data, leading to the same conclusions.
Yang-Mills gauge theory and Higgs particle
NASA Astrophysics Data System (ADS)
Wu, Tai Tsun; Wu, Sau Lan
2015-12-01
Motivated by the experimental data on the Higgs particle from the ATLAS Collaboration and the CMS Collaboration at CERN, the standard model, which is a Yang-Mills non-Abelian gauge theory with the group U(1) × SU(2) × SU(3), is augmented by scalar quarks and scalar leptons without changing the gauge group and without any additional Higgs particle. Thus there is fermion-boson symmetry between these new particles and the known quarks and leptons. In a simplest scenario, the cancellation of the quadratic divergences in this augmented standard model leads to a determination of the masses of all these scalar quarks and scalar leptons. All these masses are found to be less than 100 GeV/c2, and the right-handed scalar neutrinos are especially light. Alterative procedures are given with less reliance on the experimental data, leading to the same conclusions.
Dynamics of vortices in superconductors
Weinan, E.
1992-12-31
We study the dynamics of vortices in type-II superconductors from the point of view of time-dependent Ginzburg-Landau equations. We outline a proof of existence, uniqueness and regularity of strong solutions for these equations. We then derive reduced systems of ODEs governing the motion of the vortices in the asymptotic limit of large Ginzburg-Landau parameter.
Quantised vortices in polariton lattices
NASA Astrophysics Data System (ADS)
Berloff, Natalia
2015-11-01
The first comprehensive treatment of quantised vorticity in the light of research on vortices in modern fluid mechanics appeared in Russell Donnelly seminal research papers and summarized in his 1991 book ``Quantized Vortices in Helium II''. Recently quantized vortices have been studied in polariton condensates. Polaritons are the mixed light-matter quasi-particles that are formed in the strong exciton-photon coupling regime. Under non-resonant optical excitation rapid relaxation of carriers and bosonic stimulation result in the formation of a non-equilibrium polariton condensate characterized by a single many-body wave-function, therefore, naturally possessing quantized vortices. Polariton condensates can be imprinted into any two-dimensional lattice by spatial modulation of the pumping laser and form vortices via interacting outfows from the pumping sites. Optically pumped polariton condensates can be injected in lattice configurations with arbitrary density profiles offering the possibility to control the kinetics of the condensate and therefore the number and location of vortices. I will present some new developments in theoretical and experimental studies of quantized vortices in polariton condensates and discuss possible practical implementations of polariton lattices.
Flame propagation through periodic vortices
Dold, J.W.; Kerr, O.S.; Nikolova, I.P.
1995-02-01
The discovery of a new class of Navier-Stokes solutions representing steady periodic stretched vortices offers a useful test-bed for examining interactions between flames and complex flow-fields. After briefly describing these vortex solutions and their wide-ranging parameterization in terms of wavelength and amplitude, this article examines their effect on flames of constant normal propagation speed as observed through numerical solutions of an eikonal equation. Over certain ranges of vortex amplitude and flame-speed, a corridor of enhanced flame passage is seen to be created as a leading flame-tip managers to leap-frog between successive vortices. However, for large enough amplitudes of vorticity or small enough flame-speeds, the flame fails to be able to benefit from the advection due to the vortices. It is shown that the leading tips of such flames are effectively trapped by the stretched vortices.
Vorticity flux from active dimples
NASA Astrophysics Data System (ADS)
McKeon, Beverley; Sherwin, Spencer; Morrison, Jonathan
2004-11-01
The effect of surface depressions, or dimples, in reducing drag on golf balls is well-known. Here this concept is extended to using ``active" dimples to manipulate vorticity flux at the wall. Surface vorticity flux is governed by surface accelerations, pressure and shear stress gradients, and surface curvature. ``Active" (or vibrating) dimples may generate vorticity flux by each of these terms, making them an excellent candidate for a basic study of flux manipulation, by which flow control may be achieved. Flow over an active dimple in fully-developed laminar channel flow is simulated with velocity boundary conditions developed from a linearized perturbation method imposed at the wall. This simple model cannot capture flow separation, but gives insight into the most straightforward means of flux generation from the concave surface. Vorticity flux due to dimple geometry and motion is quantified, and enhancements of two to three orders of magnitude in peak vorticity over the static dimple case are observed.
Directed Abelian sandpile with multiple downward neighbors.
Dhar, D; Pruessner, G; Expert, P; Christensen, K; Zachariou, N
2016-04-01
We study the directed Abelian sandpile model on a square lattice, with K downward neighbors per site, K>2. The K=3 case is solved exactly, which extends the earlier known solution for the K=2 case. For K>2, the avalanche clusters can have holes and side branches and are thus qualitatively different from the K=2 case where avalanche clusters are compact. However, we find that the critical exponents for K>2 are identical with those for the K=2 case, and the large-scale structure of the avalanches for K>2 tends to the K=2 case. PMID:27176254
Directed Abelian sandpile with multiple downward neighbors
NASA Astrophysics Data System (ADS)
Dhar, D.; Pruessner, G.; Expert, P.; Christensen, K.; Zachariou, N.
2016-04-01
We study the directed Abelian sandpile model on a square lattice, with K downward neighbors per site, K >2 . The K =3 case is solved exactly, which extends the earlier known solution for the K =2 case. For K >2 , the avalanche clusters can have holes and side branches and are thus qualitatively different from the K =2 case where avalanche clusters are compact. However, we find that the critical exponents for K >2 are identical with those for the K =2 case, and the large-scale structure of the avalanches for K >2 tends to the K =2 case.
On abelian group actions and Galois quantizations
NASA Astrophysics Data System (ADS)
Huru, H. L.; Lychagin, V. V.
2013-08-01
Quantizations of actions of finite abelian groups G are explicitly described by elements in the tensor square of the group algebra of G. Over algebraically closed fields of characteristic 0 these are in one to one correspondence with the second cohomology group of the dual of G. With certain adjustments this result is applied to group actions over any field of characteristic 0. In particular we consider the quantizations of Galois extensions, which are quantized by "deforming" the multiplication. For the splitting fields of products of quadratic polynomials this produces quantized Galois extensions that all are Clifford type algebras.
Non abelian hydrodynamics and heavy ion collisions
Calzetta, E.
2014-01-14
The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined by the conservation laws of energy momentum and color currents. Therefore it is possible to describe its main features in hydrodynamic terms, the very short color neutralization time notwithstanding. In this lecture we shall give a simple derivation of the hydrodynamics of a color charged fluid, by generalizing the usual derivation of hydrodynamics from kinetic theory to the non abelian case.
Abelian BF theory and Turaev-Viro invariant
NASA Astrophysics Data System (ADS)
Mathieu, P.; Thuillier, F.
2016-02-01
The U(1) BF quantum field theory is revisited in the light of Deligne-Beilinson cohomology. We show how the U(1) Chern-Simons partition function is related to the BF one and how the latter on its turn coincides with an abelian Turaev-Viro invariant. Significant differences compared to the non-abelian case are highlighted.
Higgs central exclusive production
NASA Astrophysics Data System (ADS)
Cudell, J. R.; Dechambre, A.; Hernández, O. F.
2012-01-01
Using the CHIDe model, we tune the calculation of central exclusive Higgs production to the recent CDF central exclusive dijet data, and predict the cross section for the exclusive production of Higgs boson at the LHC. In this model, due to different choices of the scale in the Sudakov form factor for dijet and Higgs production, it is always below 1 fb, and below 0.3 fb after experimental cuts.
NASA Astrophysics Data System (ADS)
Calmet, Xavier; Kuntz, Iberê
2016-05-01
In this paper we point out that Starobinsky inflation could be induced by quantum effects due to a large non-minimal coupling of the Higgs boson to the Ricci scalar. The Higgs Starobinsky mechanism provides a solution to issues attached to large Higgs field values in the early universe which in a metastable universe would not be a viable option. We verify explicitly that these large quantum corrections do not destabilize Starobinsky's potential.
Dawson, S.; Haber, H.E.; Rindani, S.D.
1989-05-01
This is the summary report of the Higgs Boson Working Group. We discuss a variety of search techniques for a Higgs boson which is lighter than the Z. The processes K /yields/ /pi/H, /eta//prime/ /yields/ /eta/H,/Upsilon/ /yields/ H/gamma/ and e/sup +/e/sup /minus// /yields/ ZH are examined with particular attention paid to theoretical uncertainties in the calculations. We also briefly examine new features of Higgs phenomenology in a model which contains Higgs triplets as well as the usual doublet of scalar fields. 33 refs., 6 figs., 1 tab.
NASA Technical Reports Server (NTRS)
Rossow, Vernon J.
2011-01-01
As part of an ongoing effort to find ways to make vortex flow fields decompose more quickly, photographs and observations are presented of vortex flow fields that indicate the presence of multiple layers of fluid rotating about a common axis. A survey of the literature indicates that multiple-layered vortices form in waterspouts, tornadoes and lift-generated vortices of aircraft. An explanation for the appearance of multiple-layered structures in vortices is suggested. The observations and data presented are intended to improve the understanding of the formation and persistence of vortex flow fields.
Non-Abelian Anyons and Interferometry
NASA Astrophysics Data System (ADS)
Bonderson, Parsa Hassan
This thesis is primarily a study of the measurement theory of non-Abelian anyons through interference experiments. We give an introduction to the theory of anyon models, providing all the formalism necessary to apply standard quantum measurement theory to such systems. This formalism is then applied to give a detailed analysis of a Mach-Zehnder interferometer for arbitrary anyon models. In this treatment, we find that the collapse behavior exhibited by a target anyon in a superposition of states is determined by the monodromy of the probe anyons with the target. Such measurements may also be used to gain knowledge that would help to properly identify the anyon model describing an unknown system. The techniques used and results obtained from this model interferometer have general applicability, and we use them to also describe the interferometry measurements in a two point-contact interferometer proposed for non-Abelian fractional quantum Hall states. Additionally, we give the complete description of a number of important examples of anyon models, as well as their corresponding quantities that are relevant for interferometry. Finally, we give a partial classification of anyon models with small numbers of particle types.
Vorticity Transfer in Shock Wave Interactions with Turbulence and Vortices
NASA Astrophysics Data System (ADS)
Agui, J. H.; Andreopoulos, J.
1998-11-01
Time-dependent, three-dimensional vorticity measurements of shock waves interacting with grid generated turbulence and concentrated tip vortices were conducted in a large diameter shock tube facility. Two different mesh size grids and a NACA-0012 semi-span wing acting as a tip vortex generator were used to carry out different relative Mach number interactions. The turbulence interactions produced a clear amplification of the lateral and spanwise vorticity rms, while the longitudinal component remained mostly unaffected. By comparison, the tip vortex/shock wave interactions produced a two fold increase in the rms of longitudinal vorticity. Considerable attention was given to the vorticity source terms. The mean and rms of the vorticity stretching terms dominated by 5 to 7 orders of magnitude over the dilitational compression terms in all the interactions. All three signals of the stretching terms manifested very intermittent, large amplitude peak events which indicated the bursting character of the stretching process. Distributions of these signals were characterized by extremely large levels of flatness with varying degrees of skewness. These distribution patterns were found to change only slightly through the turbulence interactions. However, the tip vortex/shock wave interactions brought about significant changes in these distributions which were associated with the abrupt structural changes of the vortex after the interaction.
Studying critical string emerging from non-Abelian vortex in four dimensions
NASA Astrophysics Data System (ADS)
Koroteev, P.; Shifman, M.; Yung, A.
2016-08-01
Recently a special vortex string was found [5] in a class of soliton vortices supported in four-dimensional Yang-Mills theories that under certain conditions can become infinitely thin and can be interpreted as a critical ten-dimensional string. The appropriate bulk Yang-Mills theory has the U (2) gauge group and the Fayet-Iliopoulos term. It supports semilocal non-Abelian vortices with the world-sheet theory for orientational and size moduli described by the weighted CP (2 , 2) model. The full target space is R4 ×Y6 where Y6 is a non-compact Calabi-Yau space. We study the above vortex string from the standpoint of string theory, focusing on the massless states in four dimensions. In the generic case all massless modes are non-normalizable, hence, no massless gravitons or vector fields are predicted in the physical spectrum. However, at the selfdual point (at strong coupling) weighted CP (2 , 2) admits deformation of the complex structure, resulting in a single massless hypermultiplet in the bulk. We interpret it as a composite "baryon."
NASA Astrophysics Data System (ADS)
Papanicolaou, N.; Tomaras, T. N.
1991-08-01
The canonical conservation laws of linear and angular momentum in the ferromagnetic continuum have been known to be plagued by certain ambiguities which are resolved in this paper by constructing conservation laws as suitable moments of a topological density. The resulting canonical structure is then shown to be analogous to that encountered in the familiar Hall effect and explains the unusual features of the dynamics of magnetic vortices without resorting to a detailed solution of the underlying nonlinear equations. Thus, in the absence of external magnetic fields, a magnetic vortex is shown to be spontaneously pinned around a fixed guiding center. The guiding center would drift in a direction perpendicular to an applied magnetic field gradient, provided that dissipation can be neglected, with a Hall velocity that is calculated explicitly in terms of the initial configuration of the vortex. In the presence of dissipation, the vortex undergoes skew deflection at an angle δ ≠ 90° with respect to the applied field gradient. The angle δ is related to the winding number of the vortex according to the well-known golden rule of bubble dynamics.
NASA Astrophysics Data System (ADS)
Schröck, Mario; Vogt, Hannes
2016-01-01
On lattice gauge field configurations with 2 +1 dynamical quark flavors, we investigate the momentum space quark and gluon propagators in the combined maximally Abelian plus U (1 )3×U (1 )8 Landau gauge. We extract the gluon fields from the lattice link variables and study the diagonal and off-diagonal gluon propagators. We find that the infrared region of the transverse diagonal gluon propagator is strongly enhanced compared to the off-diagonal propagator. The Dirac operator from the Asqtad action is inverted on the diagonal and off-diagonal gluon backgrounds separately. In agreement with the hypothesis of infrared Abelian dominance, we find that the off-diagonal gluon background hardly gives rise to any nontrivial quark dynamics while the quark propagator from the diagonal gluon background closely resembles its Landau gauge counterpart.
Higgs portal vector dark matter for GeV scale γ-ray excess from galactic center
Ko, P.; Park, Wan-Il; Tang, Yong E-mail: wipark@kias.re.kr
2014-09-01
We show that the GeV scale γ-ray excess from the direction of the Galactic Center can be naturally explained by the pair annihilation of Abelian vector dark matter (VDM) into a pair of dark Higgs bosons (VV→ φ φ), followed by the subsequent decay of φ into b b-bar or τ τ-bar . All the processes are described by a renormalizable VDM model with the Higgs portal, which is naturally flavor-dependent. Some parameter space of this scenario can be tested at the near future direct dark matter search experiments such as LUX and XENON1T.
Higgs portal vector dark matter for GeV scale γ-ray excess from galactic center
Ko, P.; Park, Wan-Il; Tang, Yong
2014-09-05
We show that the GeV scale γ-ray excess from the direction of the Galactic Center can be naturally explained by the pair annihilation of Abelian vector dark matter (VDM) into a pair of dark Higgs bosons (VV→ϕϕ), followed by the subsequent decay of ϕ into bb{sup -bar} or ττ{sup -bar}. All the processes are described by a renormalizable VDM model with the Higgs portal, which is naturally flavor-dependent. Some parameter space of this scenario can be tested at the near future direct dark matter search experiments such as LUX and XENON1T.
Non-Abelian quantum error correction
NASA Astrophysics Data System (ADS)
Feng, Weibo
A quantum computer is a proposed device which would be capable of initializing, coherently manipulating, and measuring quantum states with sufficient accuracy to carry out new kinds of computations. In the standard scenario, a quantum computer is built out of quantum bits, or qubits, two-level quantum systems which replace the ordinary classical bits of a classical computer. Quantum computation is then carried out by applying quantum gates, the quantum equivalent of Boolean logic gates, to these qubits. The most fundamental barrier to building a quantum computer is the inevitable errors which occur when carrying out quantum gates and the loss of quantum coherence of the qubits due to their coupling to the environment (decoherence). Remarkably, it has been shown that in a quantum computer such errors and decoherence can be actively fought using what is known as quantum error correction. A closely related proposal for fighting errors and decoherence in a quantum computer is to build the computer out of so-called topologically ordered states of matter. These are states of matter which allow for the storage and manipulation of quantum states with a built in protection from error and decoherence. The excitations of these states are non-Abelian anyons, particle-like excitations which satisfy non-Abelian statistics, meaning that when two excitations are interchanged the result is not the usual +1 and -1 associated with identical Bosons or Fermions, but rather a unitary operation which acts on a multidimensional Hilbert space. It is therefore possible to envision computing with these anyons by braiding their world-lines in 2+1-dimensional spacetime. In this Dissertation we present explicit procedures for a scheme which lives at the intersection of these two approaches. In this scheme we envision a functioning ``conventional" quantum computer consisting of an array of qubits and the ability to carry out quantum gates on these qubits. We then give explicit quantum circuits
LHC diphoton Higgs signal predicted by little Higgs models
Wang Lei; Yang Jinmin
2011-10-01
Little Higgs theory naturally predicts a light Higgs boson whose most important discovery channel at the LHC is the diphoton signal pp{yields}h{yields}{gamma}{gamma}. In this work, we perform a comparative study for this signal in some typical little Higgs models, namely, the littlest Higgs model, two littlest Higgs models with T-parity (named LHT-I and LHT-II), and the simplest little Higgs models. We find that compared with the standard model prediction, the diphoton signal rate is always suppressed and the suppression extent can be quite different for different models. The suppression is mild (< or approx. 10%) in the littlest Higgs model but can be quite severe ({approx_equal}90%) in other three models. This means that discovering the light Higgs boson predicted by the little Higgs theory through the diphoton channel at the LHC will be more difficult than discovering the standard model Higgs boson.
Topological invariants measured for Abelian and non-Abelian monopole fields
NASA Astrophysics Data System (ADS)
Sugawa, Seiji; Salces Carcoba, Francisco; Perry, Abigail; Yue, Yuchen; Putra, Andika; Spielman, Ian
2016-05-01
Understanding the topological nature of physical systems is an important topic in contemporary physics, ranging from condensed matter to high energy. In this talk, I will present experiments measuring the 1st and 2nd Chern number in a four-level quantum system both with degenerate and non-degenerate energies. We engineered the system's Hamiltonian by coupling hyperfine ground states of rubidium-87 Bose-Einstein condensates with rf and microwave fields. We non-adiabatically drove the system and measured the linear response to obtain the local (non-Abelian) Berry curvatures. Then, the Chern numbers were evaluated on (hyper-)spherical manifolds in parameter space. We obtain Chern numbers close to unity for both the 1st and the 2nd Chern numbers. The non-zero Chern number can be interpreted as monopole residing inside the manifold. For our system, the monopoles correspond to a Dirac monopole for non-degenerate spectra and a Yang monopole for our degenerate case. We also show how the dynamical evolution under non-Abelian gauge field emerged in degenerate quantum system is different from non-degenerate case by showing path-dependent acquisition of non-Abelian geometric phase and Wilson loops.
NASA Astrophysics Data System (ADS)
Schmaltz, Martin; Tucker-Smith, David
2005-12-01
Recently there has been renewed interest in the possibility that the Higgs particle of the Standard Model is a pseudo-Nambu-Goldstone boson. This development was spurred by the observation that if certain global symmetries are broken only by the interplay between two or more coupling constants, then the Higgs mass-squared is free from quadratic divergences at one loop. This collective symmetry breaking is the essential ingredient in little Higgs theories, which are weakly coupled extensions of the Standard Model with little or no fine tuning, describing physics up to an energy scale 10 TeV. Here we give a pedagogical introduction to little Higgs theories. We review their structure and phenomenology, focusing mainly on the SU(3) theory, the Minimal Moose, and the littlest Higgs as concrete examples.
Dynamical non-Abelian two-form: BRST quantization
Lahiri, A.
1997-04-01
When an antisymmetric tensor potential is coupled to the field strength of a gauge field via a BANDF coupling and a kinetic term for B is included, the gauge field develops an effective mass. The theory can be made invariant under a non-Abelian vector gauge symmetry by introducing an auxiliary vector field. The covariant quantization of this theory requires ghosts for ghosts. The resultant theory including gauge fixing and ghost terms is BRST invariant by construction, and therefore unitary. The construction of the BRST-invariant action is given for both Abelian and non-Abelian models of mass generation. {copyright} {ital 1997} {ital The American Physical Society}
Gauge invariance for a whole Abelian model
Chauca, J.; Doria, R.; Soares, W.
2012-09-24
Light invariance is a fundamental principle for physics be done. It generates Maxwell equations, relativity, Lorentz group. However there is still space for a fourth picture be developed which is to include fields with same Lorentz nature. It brings a new room for field theory. It says that light invariance does not work just to connect space and time but it also associates different fields with same nature. Thus for the ((1/2),(1/2)) representation there is a fields family {l_brace}A{sub {mu}I}{r_brace} to be studied. This means that given such fields association one should derive its corresponding gauge theory. This is the effort at this work. Show that there is a whole gauge theory to cover these fields relationships. Considering the abelian case, prove its gauge invariance. It yields the kinetic, massive, trilinear and quadrilinear gauge invariant terms.
Jupiter's Great Red Spot and other vortices
NASA Technical Reports Server (NTRS)
Marcus, Philip S.
1993-01-01
A theoretical explanation of Jupiter's Great Red Spot (GRS) as the self-organization of vorticity in turbulence is presented. A number of properties of the GRS and other Jovian vortices that are unambiguous from the data are listed. The simplest possible model that explains these properties one at a time rather than in a difficult all-encompassing planetary global circulation model is presented. It is shown that Jovian vortices reflect the behavior of quasi-geostrophic (QG) vortices embedded in an east-west wind with bands of uniform potential vorticity. It is argued that most of the properties of the Jovian vortices can be easily explained and understood with QG theory. Many of the signatures of QG vortices are apparent on Voyager images. In numerical and laboratory experiments, QG vortices relax to approximately steady states like the Jovian vortices, rather than oscillating or rotating Kida ellipses.
Topological quantum liquids with quaternion non-Abelian statistics.
Xu, Cenke; Ludwig, Andreas W W
2012-01-27
Noncollinear magnetic order is typically characterized by a tetrad ground state manifold (GSM) of three perpendicular vectors or nematic directors. We study three types of tetrad orders in two spatial dimensions, whose GSMs are SO(3) = S(3)/Z(2), S(3)/Z(4), and S(3)/Q(8), respectively. Q(8) denotes the non-Abelian quaternion group with eight elements. We demonstrate that after quantum disordering these three types of tetrad orders, the systems enter fully gapped liquid phases described by Z(2), Z(4), and non-Abelian quaternion gauge field theories, respectively. The latter case realizes Kitaev's non-Abelian toric code in terms of a rather simple spin-1 SU(2) quantum magnet. This non-Abelian topological phase possesses a 22-fold ground state degeneracy on the torus arising from the 22 representations of the Drinfeld double of Q(8). PMID:22400884
Engineering complex topological memories from simple Abelian models
NASA Astrophysics Data System (ADS)
Wootton, James R.; Lahtinen, Ville; Doucot, Benoit; Pachos, Jiannis K.
2011-09-01
In three spatial dimensions, particles are limited to either bosonic or fermionic statistics. Two-dimensional systems, on the other hand, can support anyonic quasiparticles exhibiting richer statistical behaviors. An exciting proposal for quantum computation is to employ anyonic statistics to manipulate information. Since such statistical evolutions depend only on topological characteristics, the resulting computation is intrinsically resilient to errors. The so-called non-Abelian anyons are most promising for quantum computation, but their physical realization may prove to be complex. Abelian anyons, however, are easier to understand theoretically and realize experimentally. Here we show that complex topological memories inspired by non-Abelian anyons can be engineered in Abelian models. We explicitly demonstrate the control procedures for the encoding and manipulation of quantum information in specific lattice models that can be implemented in the laboratory. This bridges the gap between requirements for anyonic quantum computation and the potential of state-of-the-art technology.
The non-abelian tensor multiplet in loop space
NASA Astrophysics Data System (ADS)
Gustavsson, Andreas
2006-01-01
We introduce a non-abelian tensor multiplet directly in the loop space associated with flat six-dimensional Miskowski space-time, and derive the supersymmetry variations for on-shell Script N = (2,0) supersymmetry.
How rotational vortices enhance transfers
NASA Astrophysics Data System (ADS)
Griffani, D.; Rognon, P.; Metzger, B.; Einav, I.
2013-09-01
Inspired by recent observations of granular flow, we examine how rotational vortices contribute to heat or mass transfer enhancement in a fluid. We use a tracer method to simulate both diffusion and advection in systems of differing intrinsic diffusivities D0, vortex sizes R, vortex rotation frequencies f, and vortex lifetimes ℓ. The results reveal that these systems exhibit an effective diffusive behavior, characterized by an effective diffusivity Deff. A striking finding is the existence of two regimes, dichotomised by the Péclet number Pe = R2f/D0. When the Péclet number is less than one, there is no transfer enhancement, Deff = D0. For higher values, vortices produce some transfer enhancement with a corresponding power law Deff/D0 ≈ Pen. The power n ranges from a lower bound of 0.5 for stationary vortices of lifetime infinity, to an upper bound of 1 for vortices of lifetimes shorter than half a rotation. This difference is attributed to two different internal mechanisms involving the coupling of diffusion and advection. These results could provide new insights on the transfer properties of fluid systems comprising rotational vortices, such as granular materials, suspensions, foams, and emulsions, as well as low Reynolds number stirred flows.
Filamentation with nonlinear Bessel vortices.
Jukna, V; Milián, C; Xie, C; Itina, T; Dudley, J; Courvoisier, F; Couairon, A
2014-10-20
We present a new type of ring-shaped filaments featured by stationary nonlinear high-order Bessel solutions to the laser beam propagation equation. Two different regimes are identified by direct numerical simulations of the nonlinear propagation of axicon focused Gaussian beams carrying helicity in a Kerr medium with multiphoton absorption: the stable nonlinear propagation regime corresponds to a slow beam reshaping into one of the stationary nonlinear high-order Bessel solutions, called nonlinear Bessel vortices. The region of existence of nonlinear Bessel vortices is found semi-analytically. The influence of the Kerr nonlinearity and nonlinear losses on the beam shape is presented. Direct numerical simulations highlight the role of attractors played by nonlinear Bessel vortices in the stable propagation regime. Large input powers or small cone angles lead to the unstable propagation regime where nonlinear Bessel vortices break up into an helical multiple filament pattern or a more irregular structure. Nonlinear Bessel vortices are shown to be sufficiently intense to generate a ring-shaped filamentary ionized channel in the medium which is foreseen as opening the way to novel applications in laser material processing of transparent dielectrics. PMID:25401574
General composite Higgs models
NASA Astrophysics Data System (ADS)
Marzocca, David; Serone, Marco; Shu, Jing
2012-08-01
We construct a general class of pseudo-Goldstone composite Higgs models, within the minimal SO(5)/SO(4) coset structure, that are not necessarily of moose-type. We characterize the main properties these models should have in order to give rise to a Higgs mass around 125 GeV. We assume the existence of relatively light and weakly coupled spin 1 and 1/2 resonances. In absence of a symmetry principle, we introduce the Minimal Higgs Potential (MHP) hypothesis: the Higgs potential is assumed to be one-loop dominated by the SM fields and the above resonances, with a contribution that is made calculable by imposing suitable generalizations of the first and second Weinberg sum rules. We show that a 125 GeV Higgs requires light, often sub-TeV, fermion resonances. Their presence can also be important for the models to successfully pass the electroweak precision tests. Interestingly enough, the latter can also be passed by models with a heavy Higgs around 320 GeV. The composite Higgs models of the moose-type considered in the literature can be seen as particular limits of our class of models.
NASA Astrophysics Data System (ADS)
Bornheim, Adolf
2014-03-01
The Nobel Prize in physics 2013 has been awarded to François Englert and Peter W. Higgs for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles which plays a crucial role in our understanding of electro-weak symmetry breaking. I will review the experimental results manifesting the discovery of the so called Higgs boson from the perspective of the Compact Muon Solenoid (CMS) collaboration. The review is based on the final results from the proton-proton collision data at 7 TeV and 8 TeV center-of-mass energy, collected in 2011 and 2012 in the initial run of the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN). Results on the properties of the new particle with a mass around 125 GeV, all in agreement with the expectations for the Standard Model (SM) Higgs boson, are highlighted. Latest results on the couplings between the Higgs and fermionic fields, in particular the final results of searches for a Higgs boson decaying into a b-quark or a tau-lepton pair, are presented. Non-SM Higgs searches are briefly summarized. Future perspectives for Higgs physics with CMS at LHC for the next data taking period starting in 2015 and beyond are discussed. CMS Collaboration.
NASA Astrophysics Data System (ADS)
Boughezal, Radja
2015-04-01
The future of the high energy physics program will increasingly rely upon precision studies looking for deviations from the Standard Model. Run I of the Large Hadron Collider (LHC) triumphantly discovered the long-awaited Higgs boson, and there is great hope in the particle physics community that this new state will open a portal onto a new theory of Nature at the smallest scales. A precision study of Higgs boson properties is needed in order to test whether this belief is true. New theoretical ideas and high-precision QCD tools are crucial to fulfill this goal. They become even more important as larger data sets from LHC Run II further reduce the experimental errors and theoretical uncertainties begin to dominate. In this talk, I will review recent progress in understanding Higgs properties,including the calculation of precision predictions needed to identify possible physics beyond the Standard Model in the Higgs sector. New ideas for measuring the Higgs couplings to light quarks as well as bounding the Higgs width in a model-independent way will be discussed. Precision predictions for Higgs production in association with jets and ongoing efforts to calculate the inclusive N3LO cross section will be reviewed.
Higher Genus Abelian Functions Associated with Cyclic Trigonal Curves
NASA Astrophysics Data System (ADS)
England, Matthew
2010-03-01
We develop the theory of Abelian functions associated with cyclic trigonal curves by considering two new cases. We investigate curves of genus six and seven and consider whether it is the trigonal nature or the genus which dictates certain areas of the theory. We present solutions to the Jacobi inversion problem, sets of relations between the Abelian function, links to the Boussinesq equation and a new addition formula.
Barger, V.; Deshpande, N.G.; Hewett, J.L. |; Rizzo, T.G. |
1992-11-01
We investigate the possibility of a multi-Higgs doublet model where the lightest neutral Higgs boson (h{sup o}) decouples from the fermion sector. We are partially motivated by the four {ell}{sup +}{ell}{sup {minus}} events with M{gamma}{gamma} {approx_equal} 60 GeV recently observed by the L3 collaboration, which could be a signal for Z {yields} (Z{sup *} {yields} {ell}{sup +}{ell}{sup {minus}}) + (h{sup o} {yields} {gamma}{gamma}). Collider signatures for the additional physical Higgs bosons present in such models are discussed.
Asymptotically safe Higgs inflation
Xianyu, Zhong-Zhi; He, Hong-Jian E-mail: hjhe@tsinghua.edu.cn
2014-10-01
We construct a new inflation model in which the standard model Higgs boson couples minimally to gravity and acts as the inflaton. Our construction of Higgs inflation incorporates the standard model with Einstein gravity which exhibits asymptotic safety in the ultraviolet region. The slow roll condition is satisfied at large field value due to the asymptotically safe behavior of Higgs self-coupling at high energies. We find that this minimal construction is highly predictive, and is consistent with both cosmological observations and collider experiments.
Hairpin Vortices: Autogeneration and Interaction
NASA Astrophysics Data System (ADS)
Sabatino, Daniel; Maharjan, Rijan; Sanders, Andrew
2013-11-01
The regeneration of hairpin vortices is examined in a free-surface water channel where vortices are artificially generated by means of injection in a laminar boundary layer. The process is visualized with dye and hydrogen bubble-wire techniques. The strength of an isolated hairpin required to begin the autogeneration process is established by means of PIV measurements on the symmetry plane. Because hairpins are in close proximity in a fully-turbulent boundary layer, two hairpins are generated at different streamwise locations and allowed to interact at different stages of development. The relative position, strength and maturity of the interacting hairpins that generate secondary vortices are examined. The morphology of the generation process and of the resulting secondary hairpin for both the isolated and interacting cases are discussed and compared to previous work. Supported by the National Science Foundation under Grant CBET-1040236.
Multiflavor QCD∗ on R3 ×S1: Studying transition from Abelian to non-Abelian confinement
NASA Astrophysics Data System (ADS)
Shifman, M.; Ünsal, M.
2009-11-01
The center-stabilized multiflavor QCD∗ theories formulated on R3 ×S1 exhibit both Abelian and non-Abelian confinement as a function of the S1 radius, similar to the Seiberg-Witten theory as a function of the mass deformation parameter. For sufficiently small number of flavors and small r (S1), we show occurrence of a mass gap in gauge fluctuations, and linear confinement. This is a regime of confinement without continuous chiral symmetry breaking (χSB). Unlike one-flavor theories where there is no phase transition in r (S1), the multiflavor theories possess a single phase transition associated with breaking of the continuous χS. We conjecture that the scale of the χSB is parametrically tied up with the scale of Abelian to non-Abelian confinement transition.
NASA Astrophysics Data System (ADS)
Porto, Rafael A.; Zee, A.
2008-09-01
We introduce Higgs democracy in the Yukawa sector by constructing a model with a private Higgs and a dark scalar for each fermion thus addressing the large hierarchy among fermion masses. The model has interesting implications for the LHC, while the Standard Model phenomenology is recovered at low energies. We discuss some phenomenological implications such as FCNC, new Higgses at the TeV scale and dark matter candidates.
NASA Astrophysics Data System (ADS)
Eto, Minoru; Murakami, Yoshihide
2015-03-01
Dyonic non-Abelian local/semi-global vortex strings are studied in detail in supersymmetric/non-supersymmetric Yang-Mills-Higgs theories. While the BPS tension formula is known to be the same as that for the BPS dyonic instanton, we find that the non-BPS tension formula is approximated very well by the well-known tension formula of the BPS dyon. We show that this mysterious tension formula for the dyonic non-BPS vortex stings can be understood from the perspective of a low energy effective field theory. Furthermore, we propose an efficient method to obtain an effective theory of a single vortex string, which includes not only lower derivative terms but also all order derivative corrections by making use of the tension formula. We also find a novel dyonic vortex string whose internal orientation vectors rotate in time and spiral along the string axis.
NASA Astrophysics Data System (ADS)
Brivio, I.; Éboli, O. J. P.; Gavela, M. B.; Gonzalez-García, M. C.; Merlo, L.; Rigolin, S.
2014-12-01
We analyze the leading effective operators which induce a quartic momentum dependence in the Higgs propagator, for a linear and for a non-linear realization of electroweak symmetry breaking. Their specific study is relevant for the understanding of the ultraviolet sensitivity to new physics. Two methods of analysis are applied, trading the Lagrangian coupling by: i) a "ghost" scalar, after the Lee-Wick procedure; ii) other effective operators via the equations of motion. The two paths are shown to lead to the same effective Lagrangian at first order in the operator coefficients. It follows a modification of the Higgs potential and of the fermionic couplings in the linear realization, while in the non-linear one anomalous quartic gauge couplings, Higgs-gauge couplings and gauge-fermion interactions are induced in addition. Finally, all LHC Higgs and other data presently available are used to constrain the operator coefficients; the future impact of pp → 4 leptons data via off-shell Higgs exchange and of vector boson fusion data is considered as well. For completeness, a summary of pure-gauge and gauge-Higgs signals exclusive to non-linear dynamics at leading-order is included.
Higgs dynamics during inflation
Enqvist, Kari; Meriniemi, Tuukka; Nurmi, Sami E-mail: tuukka.meriniemi@helsinki.fi
2014-07-01
We investigate inflationary Higgs dynamics and constraints on the Standard Model parameters assuming the Higgs potential, computed to next-to-next leading order precision, is not significantly affected by new physics. For a high inflationary scale H ∼ 10{sup 14} GeV suggested by BICEP2, we show that the Higgs is a light field subject to fluctuations which affect its dynamics in a stochastic way. Starting from its inflationary value the Higgs must be able to relax to the Standard Model vacuum well before the electroweak scale. We find that this is consistent with the high inflationary scale only if the top mass m{sub t} is significantly below the best fit value. The region within 2σ errors of the measured m{sub t}, the Higgs mass m{sub h} and the strong coupling α{sub s} and consistent with inflation covers approximately the interval m{sub t}∼<171.8 GeV+0.538(m{sub h}−125.5 GeV) with 125.4 GeV∼
Black holes and Abelian symmetry breaking
NASA Astrophysics Data System (ADS)
Chagoya, Javier; Niz, Gustavo; Tasinato, Gianmassimo
2016-09-01
Black hole configurations offer insights on the nonlinear aspects of gravitational theories, and can suggest testable predictions for modifications of General Relativity. In this work, we examine exact black hole configurations in vector–tensor theories, originally proposed to explain dark energy by breaking the Abelian symmetry with a non-minimal coupling of the vector to gravity. We are able to evade the no-go theorems by Bekenstein on the existence of regular black holes in vector–tensor theories with Proca mass terms, and exhibit regular black hole solutions with a profile for the longitudinal vector polarisation, characterised by an additional charge. We analytically find the most general static, spherically symmetric black hole solutions with and without a cosmological constant, and study in some detail their features, such as how the geometry depends on the vector charges. We also include angular momentum, and find solutions describing slowly-rotating black holes. Finally, we extend some of these solutions to higher dimensions.
On the light quark mass effects in Higgs boson production in gluon fusion
NASA Astrophysics Data System (ADS)
Melnikov, Kirill; Penin, Alexander
2016-05-01
Production of Higgs bosons at the LHC is affected by the contribution of light quarks, that mediate the gg → Hg transition. Although their impact is suppressed by small Yukawa couplings, it is enhanced by large logarithms of the ratio of the Higgs boson mass or its transverse momentum to light quark masses. We study the origin of this enhancement, focusing on the abelian corrections to gg → Hg amplitudes of the form {({C}_F{α}_s{mathcal{L}}^2)}^n , where mathcal{L}in \\{ ln (s/{m}_b^2),kern0.5em ln ({p}_{perp}^2/{m}_b^2)\\} . We show how these non-Sudakov double logarithmic terms can be resummed to all orders in the strong coupling constant. Interestingly, we find that the transverse momentum dependence of these corrections is very weak due to a peculiar cancellation between different logarithmic terms. Although the abelian part of QCD corrections is not expected to be dominant, it can be used to estimate missing higher-order corrections to light quark contributions to Higgs boson production at the LHC.
Paraboloids and Vortices in Hydrodynamics
ERIC Educational Resources Information Center
Goodman, John M.
1969-01-01
Describes an apparatus designed to demonstrate vortical flow of a fluid. The apparatus consists of a transparent acrylic cylinder, with a drain hole, and mounted so that it can be rotated about its axis at speeds up to 1000 rpm. Experimental observations with water as the fluid under study are reported. (LC)
Combustor with multistage internal vortices
Shang, Jer Y.; Harrington, Richard E.
1989-01-01
A fluidized bed combustor is provided with a multistage arrangement of vortex generators in the freeboard area. The vortex generators are provided by nozzle means which extend into the interior of the freeboard for forming vortices within the freeboard area to enhance the combustion of particulate material entrained in product gases ascending into the freeboard from the fluidized bed. Each of the nozzles are radially inwardly spaced from the combustor walls defining the freeboard to provide for the formation of an essentially vortex-free, vertically extending annulus about the vortices whereby the particulate material centrifuged from the vortices against the inner walls of the combustor is returned through the annulus to the fluidized bed. By adjusting the vortex pattern within the freeboard, a significant portion of the full cross-sectional area of the freeboard except for the peripheral annulus can be contacted with the turbulent vortical flow for removing the particulate material from the gaseous products and also for enhancing the combustion thereof within the freeboard.
Combustor with multistage internal vortices
Shang, Jer Yu; Harrington, R.E.
1987-05-01
A fluidized bed combustor is provided with a multistage arrangement of vortex generators in the freeboard area. The vortex generators are provided by nozzle means which extend into the interior of the freeboard for forming vortices within the freeboard areas to enhance the combustion of particulate material entrained in product gases ascending into the freeboard from the fluidized bed. Each of the nozzles are radially inwardly spaced from the combustor walls defining the freeboard to provide for the formation of an essentially vortex-free, vertically extending annulus about the vortices whereby the particulate material centrifuged from the vortices against the inner walls of the combustor is returned through the annulus to the fluidized bed. By adjusting the vortex pattern within the freeboard, a significant portion of the full cross-sectional area of the freeboard except for the peripheral annulus can be contacted with the turbulent vortical flow for removing the particulate material from the gaseous products and also for enhancing the combustion thereof within the freeboard. 2 figs.
Adiabatic dynamics of magnetic vortices
NASA Astrophysics Data System (ADS)
Papanicolaou, N.
1994-03-01
We formulate a reasonably detailed adiabatic conjecture concerning the dynamics of skew deflection of magnetic vortices in a field gradient, which is expected to be valid at sufficiently large values of the winding number. The conjecture is consistent with the golden rule used to describe the dynamics of realistic magnetic bubbles and is verified here numerically within the 2-D isotropic Heisenberg model.
Stochastic Vorticity and Associated Filtering Theory
Amirdjanova, A.; Kallianpur, G.
2002-12-19
The focus of this work is on a two-dimensional stochastic vorticity equation for an incompressible homogeneous viscous fluid. We consider a signed measure-valued stochastic partial differential equation for a vorticity process based on the Skorohod-Ito evolution of a system of N randomly moving point vortices. A nonlinear filtering problem associated with the evolution of the vorticity is considered and a corresponding Fujisaki-Kallianpur-Kunita stochastic differential equation for the optimal filter is derived.
Nonperturbative construction of massive Yang-Mills fields without the Higgs field
NASA Astrophysics Data System (ADS)
Kondo, Kei-Ichi
2013-01-01
In order to understand the so-called decoupling solution for gluon and ghost propagators in QCD, we give a nonperturbative construction of a massive vector field describing a non-Abelian massive spin-one particle, which has the correct physical degrees of freedom and is invariant under a modified Becchi-Rouet-Stora-Tyutin transformation, in a massive Yang-Mills model without the Higgs field, i.e., the Curci-Ferrari model. The resulting non-Abelian massive vector boson field is written by using a nonlinear but local transformation from the original fields in the Curci-Ferrari model. As an application, we write down a local mass term for the Yang-Mills field and a dimension-two condensate, which are exactly invariant under the modified Becchi-Rouet-Stora-Tyutin transformation, Lorentz transformation, and color rotation.
Origins of inert Higgs doublets
NASA Astrophysics Data System (ADS)
Kephart, Thomas W.; Yuan, Tzu-Chiang
2016-05-01
We consider beyond the standard model embedding of inert Higgs doublet fields. We argue that inert Higgs doublets can arise naturally in grand unified theories where the necessary associated Z2 symmetry can occur automatically. Several examples are discussed.
Vorticity from Isocurvature in the Early Universe
NASA Astrophysics Data System (ADS)
Christopherson, Adam J.; Malik, Karim A.
2015-01-01
Vorticity is ubiquitous in nature however, to date, studies of vorticity in cosmology and the early universe have been quite rare. In this paper, based on a talk in session CM1 of the 13th Marcel Grossmann Meeting, we consider vorticity generation from scalar cosmological perturbations of a perfect fluid system. We show that, at second order in perturbation theory, vorticity is sourced by a coupling between energy density and entropy gradients, thus extending a well-known feature of classical fluid dynamics to a relativistic cosmological framework. This induced vorticity, sourced by isocurvature perturbations, may prove useful in the future as an additional discriminator between inflationary models.
Potential Vorticity Structure of the Mars Polar Vortices
NASA Astrophysics Data System (ADS)
Guzewich, S.; Toigo, A. D.; Waugh, D.; Montabone, L.; Greybush, S. J.
2015-12-01
The increasing sophistication of Mars general circulation models (MGCMs) and the availability of regular atmospheric observations have allowed several teams to begin to assimilate these observations into their MGCMs and produce atmospheric reanalyses that enable, among other things, the potential vorticity (PV) structure of the Martian polar vortices to be examined. Here we perform such an analysis using the Mars Analysis Correction Data Assimilation (MACDA, Montabone et al., 2013) and the Ensembles Mars Reanalysis System (EMARS, Greybush et al., 2012) reanalyses together with free-running MGCM simulations. Monthly-mean fields from the reanalyses and MGCMs show strong westerly winds in northern mid-high latitudes during NH winter, with near-zero PV at and equatorward of the maximum winds (jet core) and steep meridional PV gradients poleward of the jet core. Furthermore, in the lower atmosphere the maximum PV occurs off the pole and monthly-mean maps show a continuous ring (annulus) of high PV. On shorter (e.g., daily) time scales a different picture emerges, with maps showing multiple small-scale coherent regions of high PV that rotate around the pole, and only when averaged over monthly times does a high PV annulus appear. A PV budget analysis is performed to examine the cause of the annulus of high PV. We also relate the ring of small-scale vortices to the stability of the PV annulus, and discuss the implications on meridional transport between mid and high latitudes.
Jupiter's closed cyclones and anticyclones vorticity
NASA Astrophysics Data System (ADS)
Legarreta, J.; Sánchez-Lavega, A.
2003-05-01
We have measured the motions and derived de velocity field tracking the cloud elements present in Jovian large-scale cyclones and anticyclones. We have used very high spatial resolution images obtained by the Voyager 1 and 2 (in 1979) and the Galileo (1997-1999) spacecrafts. In total we measured motions in 13 vortices covering a range of latitudes from -59 deg to + 41 deg. The tangential component of the velocity as a function of the distance to the vortex centre and position angle is used to retrieve the vorticity field. Then, we compare each vortex mean vorticity with the ambient and planetary vorticities (i. e. with latitude). For most cases studied (11), the vortex vorticity is greater than the ambient vorticity, although two types of vortices showed the same vorticity than the ambient, suggesting that their periphery motions can be entrained by the ambient shear. We present an analysis of the correlations between the mean vorticity and mean zonal motion of each vortex, and the relationship between the ambient to intrinsic vorticity versus the zonal to meridional size ratio. This is used to demonstrate that most vortices do not follow the Kida type vortex relationship. Acknowledgements: This work was supported by the Spanish MCYT PNAYA 2000-0932 and Grupos-UPV/EHU. We acknowledge the access to the Voyager and Galileo images through the NASA - PDS Atmospheric node at NMSU.
Resolution of Chern-Simons-Higgs Vortex Equations
NASA Astrophysics Data System (ADS)
Han, Xiaosen; Lin, Chang-Shou; Yang, Yisong
2016-04-01
It is well known that the presence of multiple constraints of non-Abelian relativisitic Chern-Simons-Higgs vortex equations makes it difficult to develop an existence theory when the underlying Cartan matrix K of the equations is that of a general simple Lie algebra and the strongest result in the literature so far is when the Cartan subalgebra is of dimension 2. In this paper we overcome this difficulty by implicitly resolving the multiple constraints using a degree-theorem argument, utilizing a key positivity property of the inverse of the Cartan matrix deduced in an earlier work of Lusztig and Tits, which enables a process that converts the equality constraints to inequality constraints in the variational formalism. Thus this work establishes a general existence theorem that settles a long-standing open problem in the field regarding the general solvability of the equations.
Mechanical Control of Individual Superconducting Vortices.
Kremen, Anna; Wissberg, Shai; Haham, Noam; Persky, Eylon; Frenkel, Yiftach; Kalisky, Beena
2016-03-01
Manipulating individual vortices in a deterministic way is challenging; ideally, manipulation should be effective, local, and tunable in strength and location. Here, we show that vortices respond to local mechanical stress applied in the vicinity of the vortex. We utilized this interaction to move individual vortices in thin superconducting films via local mechanical contact without magnetic field or current. We used a scanning superconducting quantum interference device to image vortices and to apply local vertical stress with the tip of our sensor. Vortices were attracted to the contact point, relocated, and were stable at their new location. We show that vortices move only after contact and that more effective manipulation is achieved with stronger force and longer contact time. Mechanical manipulation of vortices provides a local view of the interaction between strain and nanomagnetic objects as well as controllable, effective, and reproducible manipulation technique. PMID:26836018
Mechanical Control of Individual Superconducting Vortices
2016-01-01
Manipulating individual vortices in a deterministic way is challenging; ideally, manipulation should be effective, local, and tunable in strength and location. Here, we show that vortices respond to local mechanical stress applied in the vicinity of the vortex. We utilized this interaction to move individual vortices in thin superconducting films via local mechanical contact without magnetic field or current. We used a scanning superconducting quantum interference device to image vortices and to apply local vertical stress with the tip of our sensor. Vortices were attracted to the contact point, relocated, and were stable at their new location. We show that vortices move only after contact and that more effective manipulation is achieved with stronger force and longer contact time. Mechanical manipulation of vortices provides a local view of the interaction between strain and nanomagnetic objects as well as controllable, effective, and reproducible manipulation technique. PMID:26836018
G2HDM: Gauged Two Higgs Doublet Model
NASA Astrophysics Data System (ADS)
Huang, Wei-Chih; Tsai, Yue-Lin Sming; Yuan, Tzu-Chiang
2016-04-01
A novel model embedding the two Higgs doublets in the popular two Higgs doublet models into a doublet of a non-abelian gauge group SU(2) H is presented. The Standard Model SU(2) L right-handed fermion singlets are paired up with new heavy fermions to form SU(2) H doublets, while SU(2) L left-handed fermion doublets are singlets under SU(2) H . Distinctive features of this anomaly-free model are: (1) Electroweak symmetry breaking is induced from spontaneous symmetry breaking of SU(2) H via its triplet vacuum expectation value; (2) One of the Higgs doublet can be inert, with its neutral component being a dark matter candidate as protected by the SU(2) H gauge symmetry instead of a discrete Z 2 symmetry in the usual case; (3) Unlike Left-Right Symmetric Models, the complex gauge fields ( W 1 ' ∓ W 2 ' ) (along with other complex scalar fields) associated with the SU(2) H do not carry electric charges, while the third component W 3 ' can mix with the hypercharge U(1) Y gauge field and the third component of SU(2) L ; (4) Absence of tree level flavour changing neutral current is guaranteed by gauge symmetry; and etc. In this work, we concentrate on the mass spectra of scalar and gauge bosons in the model. Constraints from previous Z' data at LEP and the Large Hadron Collider measurements of the Standard Model Higgs mass, its partial widths of γγ and Zγ modes are discussed.
NASA Astrophysics Data System (ADS)
Pogrebkov, A. K.
2016-06-01
We show that the non-Abelian Hirota difference equation is directly related to a commutator identity on an associative algebra. Evolutions generated by similarity transformations of elements of this algebra lead to a linear difference equation. We develop a special dressing procedure that results in an integrable non-Abelian Hirota difference equation and propose two regular reduction procedures that lead to a set of known equations, Abelian or non-Abelian, and also to some new integrable equations.
Non-Abelian bosonic currents in cosmic strings
Lilley, Marc; Di Marco, Fabrizio; Martin, Jerome; Peter, Patrick
2010-07-15
A non-Abelian generalization of the neutral Witten current-carrying string model is discussed in which the bosonic current carrier belongs to a two-dimensional representation of SU(2). We find that the current-carrying solutions can be of three different kinds: either the current spans a U(1) subgroup, and in which case one is left with an Abelian current-carrying string, or the three currents are all lightlike, traveling in the same direction (only left or right movers). The third, genuinely non-Abelian situation, cannot be handled within a cylindrically symmetric framework, but can be shown to depend on all possible string Lorentz invariant quantities that can be constructed out of the phase gradients.
Non-Abelian quantum holonomy of hydrogenlike atoms
Mousolou, Vahid Azimi; Canali, Carlo M.; Sjoeqvist, Erik
2011-09-15
We study the Uhlmann holonomy [Rep. Math. Phys. 24, 229 (1986)] of quantum states for hydrogenlike atoms where the intrinsic spin and orbital angular momentum are coupled by the spin-orbit interaction and are subject to a slowly varying magnetic field. We show that the holonomy for the orbital angular momentum and spin subsystems is non-Abelian while the holonomy of the whole system is Abelian. Quantum entanglement in the states of the whole system is crucially related to the non-Abelian gauge structure of the subsystems. We analyze the phase of the Wilson loop variable associated with the Uhlmann holonomy and find a relation between the phase of the whole system and corresponding marginal phases. Based on the results for the model system, we provide evidence that the phase of the Wilson loop variable and the mixed-state geometric phase [E. Sjoeqvist et al., Phys. Rev. Lett. 85, 2845 (2000).] are generally inequivalent.
The Hilbert scheme of points for supersingular abelian surfaces
NASA Astrophysics Data System (ADS)
Schröer, Stefan
2009-04-01
We study the geometry of Hilbert schemes of points on abelian surfaces and Beauville’s generalized Kummer varieties in positive characteristics. The main result is that, in characteristic two, the addition map from the Hilbert scheme of two points to the abelian surface is a quasifibration such that all fibers are nonsmooth. In particular, the corresponding generalized Kummer surface is nonsmooth, and minimally elliptic singularities occur in the supersingular case. We unravel the structure of the singularities in dependence of p-rank and a-number of the abelian surface. To do so, we establish a McKay Correspondence for Artin’s wild involutions on surfaces. Along the line, we find examples of canonical singularities that are not rational singularities.
Chern-Simons number diffusion in (1+1)-dimensional Higgs theory
Forcrand, P.d.; Krasnitz, A. ); Potting, R. )
1994-11-15
We study the Chern-Simons number diffusion rate in the (1+1)-dimensional lattice Abelian Higgs model at temperatures much higher than, as well as comparable to, the sphaleron energy. It is found that in the high-temperature limit the rate is likely to grow as a power of 2/3 of the temperature. In the intermediate-temperature regime, our numerical simulations show that the very weak temperature dependence of the rate, found in previous work, persists at smaller lattice spacings. We discuss possibilities of relating the observed behavior of the rate to static finite-temperature properties of the model.
Gauge invariance and the physical spectrum in the two-Higgs-doublet model
NASA Astrophysics Data System (ADS)
Maas, Axel; Pedro, Leonardo
2016-03-01
Observable states are gauge invariant. In a non-Abelian gauge theory, these are necessarily composite operators. We investigate the spectrum of these operators in the two-Higgs-doublet model. For this purpose, we are working along the lines of the Fröhlich-Morchio-Strocchi mechanism to relate the physical spectrum to the spectrum of the elementary particles. We also investigate the consequences of spontaneous breaking of the global (custodial) symmetry group. Finally, we briefly comment on how to test the results using lattice methods.
Dynamical symmetry breaking, gauge fields, and stability in four-Fermi, non-abelian interactions
Portney, M.N.
1983-01-01
The Nambu model of dynamical breaking of global symmetry is extended to the case of non-abelian SU(N) models. The possible patterns of symmetry breaking are investigated, and the masses of the composite spinless particles are found. Corresponding to each broken generator, this composite is the massless Goldstone boson. When the global symmetries are made local by the addition of gauge fields, the composite pseudoscalar Goldstone bosons disappear and the axial gauge fields become massive. This is analogous to the Higgs mechanism, but without the introduction of fundamental scalar fields. The composite scalar Goldstone bosons remain in the theory, and the vector gauge fields are still massless. This is in agreement with the charge conjugation argument. The stability of the possible solutions is discussed using several criteria. It is concluded that in theories with zero bare mass, if a nontrivial solution exists, the completely symmetric massive solution is realized. If the bare mass is symmetric and non-zero, asymmetric solutions may be found, with corresponding scalar Goldstone composites. These violate the persistent mass condition of Preskill and Weinberg.
Breathers on quantized superfluid vortices.
Salman, Hayder
2013-10-18
We consider the propagation of breathers along a quantized superfluid vortex. Using the correspondence between the local induction approximation (LIA) and the nonlinear Schrödinger equation, we identify a set of initial conditions corresponding to breather solutions of vortex motion governed by the LIA. These initial conditions, which give rise to a long-wavelength modulational instability, result in the emergence of large amplitude perturbations that are localized in both space and time. The emergent structures on the vortex filament are analogous to loop solitons but arise from the dual action of bending and twisting of the vortex. Although the breather solutions we study are exact solutions of the LIA equations, we demonstrate through full numerical simulations that their key emergent attributes carry over to vortex dynamics governed by the Biot-Savart law and to quantized vortices described by the Gross-Pitaevskii equation. The breather excitations can lead to self-reconnections, a mechanism that can play an important role within the crossover range of scales in superfluid turbulence. Moreover, the observation of breather solutions on vortices in a field model suggests that these solutions are expected to arise in a wide range of other physical contexts from classical vortices to cosmological strings. PMID:24182275
Breathers on Quantized Superfluid Vortices
NASA Astrophysics Data System (ADS)
Salman, Hayder
2013-10-01
We consider the propagation of breathers along a quantized superfluid vortex. Using the correspondence between the local induction approximation (LIA) and the nonlinear Schrödinger equation, we identify a set of initial conditions corresponding to breather solutions of vortex motion governed by the LIA. These initial conditions, which give rise to a long-wavelength modulational instability, result in the emergence of large amplitude perturbations that are localized in both space and time. The emergent structures on the vortex filament are analogous to loop solitons but arise from the dual action of bending and twisting of the vortex. Although the breather solutions we study are exact solutions of the LIA equations, we demonstrate through full numerical simulations that their key emergent attributes carry over to vortex dynamics governed by the Biot-Savart law and to quantized vortices described by the Gross-Pitaevskii equation. The breather excitations can lead to self-reconnections, a mechanism that can play an important role within the crossover range of scales in superfluid turbulence. Moreover, the observation of breather solutions on vortices in a field model suggests that these solutions are expected to arise in a wide range of other physical contexts from classical vortices to cosmological strings.
Vortices in vibrated granular rods
NASA Astrophysics Data System (ADS)
Neicu, Toni; Kudrolli, Arshad
2002-03-01
We report the first experimental observation of vortex patterns in granular rods inside a container that is vibrated vertically . The experiments were carried out with an anodized aluminum circular container which is rigidly attached to an electromagnetic shaker and the patterns are imaged using a high-frame rate digital camera. At low rod numbers and driving amplitudes, the rods are observed to lie horizontally. Above a critical number or packing fraction of rods, moving domains of vertical rods are spontaneously observed to form which coexist with horizontal rods. These small domains of vertical rods coarsen over time to form a few large vortices. The size of the vortices increases with the number of rods. We are able to track the ends of the vertical rods and obtain the velocity fields of the vortices. The mean azimuthal velocity as a function of distance from the center of the vortex is obtained as a function of the packing fraction. We will report the phase diagram of the various patterns observed as function of number of rods and driving amplitude. The mechanism for the formation and motion of the domains of vertical rods will be also discussed.
Buoyancy-Induced, Columnar Vortices
NASA Astrophysics Data System (ADS)
Simpson, Mark; Glezer, Ari
2015-11-01
Free buoyancy-induced, columnar vortices (dust devils) that are driven by thermal instabilities of ground-heated, stratified air in areas with sufficient insolation convert the potential energy of low-grade heat in the surface air layer into a vortex flow with significant kinetic energy. A variant of the naturally-occurring vortex is deliberately triggered and anchored within an azimuthal array of vertical, stator-like flow vanes that form an open-top enclosure and impart tangential momentum to the radially entrained air. This flow may be exploited for power generation by coupling the vortex to a vertical-axis turbine. The fundamental mechanisms associated with the formation, evolution, and dynamics of an anchored, buoyancy-driven columnar vortex within such a facility are investigated experimentally using a heated ground plane. Specific emphasis is placed on the manipulation of the vortex formation and structure and the dependence of the vorticity production and sustainment mechanisms on the thermal resources and characteristic scales of the anchoring flow vanes using stereo-PIV. It is shown that manipulation of the formation and advection of vorticity concentrations within the enclosure can be exploited for increasing the available kinetic energy. Supported by ARPA-E.
Correlation-induced non-Abelian quantum holonomies
NASA Astrophysics Data System (ADS)
Johansson, Markus; Ericsson, Marie; Singh, Kuldip; Sjöqvist, Erik; Williamson, Mark S.
2011-04-01
In the context of two-particle interferometry, we construct a parallel transport condition that is based on the maximization of coincidence intensity with respect to local unitary operations on one of the subsystems. The dependence on correlation is investigated and it is found that the holonomy group is generally non-Abelian, but Abelian for uncorrelated systems. It is found that our framework contains the Lévay geometric phase (2004 J. Phys. A: Math. Gen. 37 1821) in the case of two-qubit systems undergoing local SU(2) evolutions.
Ward-Takahashi identities for Abelian chiral gauge theories
NASA Astrophysics Data System (ADS)
de Lima, Ana Paula Cardoso Rodrigues; Dias, Sebastião Alves
2016-04-01
By considering a general Abelian chiral gauge theory, we investigate the behavior of anomalous Ward-Takahashi (WT) identities concerning their prediction for the usual relationship between the vertex and two-point fermion functions. Using gauge anomaly vanishing results, we show that the usual (in the nonanomalous case) WT identity connecting the vertex and two-point fermion 1PI functions is modified for Abelian chiral gauge theories. The modification, however, implies a relation between fermion and charge renormalization constants that can be important in a future study of renormalization of such theories.
Non-Abelian family symmetries as portals to dark matter
NASA Astrophysics Data System (ADS)
de Medeiros Varzielas, I.; Fischer, O.
2016-01-01
Non-Abelian family symmetries offer a very promising explanation for the flavour structure in the Standard Model and its extensions. We explore the possibility that dark matter consists in fermions that transform under a family symmetry, such that the visible and dark sector are linked by the familons - Standard Model gauge singlet scalars, responsible for spontaneously breaking the family symmetry. We study three representative models with non-Abelian family symmetries that have been shown capable to explain the masses and mixing of the Standard Model fermions.
Harnik, Roni
2004-10-27
Supersymmetric models have traditionally been assumed to be perturbative up to high scales due to the requirement of calculable unification. In this note I review the recently proposed `Fat Higgs' model which relaxes the requirement of perturbativity. In this framework, an NMSSM-like trilinear coupling becomes strong at some intermediate scale. The NMSSM Higgses are meson composites of an asymptotically-free gauge theory. This allows us to raise the mass of the Higgs, thus alleviating the MSSM of its fine tuning problem. Despite the strong coupling at an intermediate scale, the UV completion allows us to maintain gauge coupling unification.
Constraints on abelian extensions of the Standard Model from two-loop vacuum stability and U(1) B- L
NASA Astrophysics Data System (ADS)
Corianò, Claudio; Rose, Luigi Delle; Marzo, Carlo
2016-02-01
We present a renormalization group study of the scalar potential in a minimal U(1) B- L extension of the Standard Model involving one extra heavier Higgs and three heavy right-handed neutrinos with family universal B-L charge assignments. We implement a type-I seesaw for the masses of the light neutrinos of the Standard Model. In particular, compared to a previous study, we perform a two-loop extension of the evolution, showing that two-loop effects are essential for the study of the stability of the scalar potential up to the Planck scale. The analysis includes the contribution of the kinetic mixing between the two abelian gauge groups, which is radiatively generated by the evolution, and the one-loop matching conditions at the electroweak scale. By requiring the stability of the potential up to the Planck mass, significant constraints on the masses of the heavy neutrinos, on the gauge couplings and the mixing in the Higgs sector are identified.
NASA Astrophysics Data System (ADS)
Deveaud-Plédran, Benoit
2012-02-01
Polariton quantum fluids may be created both spontaneously through a standard phase transition towards a Bose Einstein condensate, or may be resonantly driven with a well-defined speed. Thanks to the photonic component of polaritons, the properties of the quantum fluid may be accessed rather directly with in particular the possibility of detained interferometric studies. Here, I will detail the dynamics of vortices, obtained with a picosecond time resolution, in different configurations, with in particular their phase dynamics. I will show in particular the dynamics the dynamics of spontaneous creation of a vortex, the dissociation of a full vortex into two half vortices as well as the dynamics of the dissociation of a dark soliton line into a street of pairs of vortices. Work done at EPFL by a dream team of Postdocs PhD students and collaborators: K. Lagoudakis, G. Nardin, T. Paraiso, G. Grosso, F. Manni, Y L'eger, M. Portella Oberli, F. Morier-Genoud and the help of our friend theorists V, Savona, M. Vouters and T. Liew.
Gauged Two Higgs Doublet Model confronts the LHC 750 GeV diphoton anomaly
NASA Astrophysics Data System (ADS)
Huang, Wei-Chih; Tsai, Yue-Lin Sming; Yuan, Tzu-Chiang
2016-08-01
In light of the recent 750 GeV diphoton anomaly observed at the LHC, we study the possibility of accommodating the deviation from the standard model prediction based on the recently proposed Gauged Two Higgs Doublet Model. The model embeds two Higgs doublets into a doublet of a non-abelian gauge group SU(2)H, while the standard model SU(2)L right-handed fermion singlets are paired up with new heavy fermions to form SU(2)H doublets, and SU(2)L left-handed fermion doublets are singlets under SU(2)H. An SU(2)H scalar doublet, which provides masses to the new heavy fermions as well as the SU(2)H gauge bosons, can be produced via gluon fusion and subsequently decays into two photons with the new fermions circulating the triangle loops to account for the deviation from the standard model prediction.
Higgs inflation and naturalness
NASA Astrophysics Data System (ADS)
Lerner, Rose N.; McDonald, John
2010-04-01
Inflation based on scalar fields which are non-minimally coupled to gravity has been proposed as a way to unify inflation with weak-scale physics, with the inflaton being identified with the Higgs boson or other weak-scale scalar particle. These models require a large non-minimal coupling ξ ~ 104 to have agreement with the observed density perturbations. However, it has been suggested that such models are unnatural, due to an apparent breakdown of the calculation of Higgs-Higgs scattering via graviton exchange in the Jordan frame. Here we argue that Higgs inflation models are in fact natural and that the breakdown does not imply new physics due to strong-coupling effects or unitarity breakdown, but simply a failure of perturbation theory in the Jordan frame as a calculational method. This can be understood by noting that the model is completely consistent when analysed in the Einstein frame and that scattering rates in the two frames are equal by the Equivalence Theorem for non-linear field redefinitions.
CDF's Higgs sensitivity status
Junk, Tom; /Illinois U., Urbana
2005-10-01
The combined sensitivity of CDF's current Standard Model Higgs boson searches is presented. The expected 95% CL limits on the production cross section times the relevant Higgs boson branching ratios are computed for the W{sup {+-}}H {yields} {ell}{sup {+-}}{nu}b{bar b}, ZH {yields} {nu}{bar {nu}}b{bar b}, gg {yields} H {yields} W{sup +}W{sup -} W{sup {+-}}H {yields} W{sup {+-}}W{sup +}W{sup -} channels as they stand as of the October 2005, using results which were prepared for Summer 2005 conferences and a newer result form the gg {yields} H {yields} W{sup +}W{sup -} channel. Correlated and uncorrelated systematic uncertainties are taken into account, and the luminosity requirements for 95% CL exclusion, 3{sigma} evidence, and 5{sigma} discovery are computed for median experimental outcomes. A list of improvements required to achieve the sensitivity to a SM Higgs boson as quantified in the Higgs Sensitivity Working Group's report is provided.
Gordon, H.A.
1984-01-01
The prospects for detecting heavy Higgs are discussed. In particular a general procedure is developed which includes studying first the characteristics of producing the signal, estimating the most important background, simulating both types of events via Monte Carlo techniques in an appropriate detector and concluding with the prospects for detection. 20 references.
Plane mixing layer vortical structure kinematics
NASA Technical Reports Server (NTRS)
Leboeuf, Richard L.
1993-01-01
The objective of the current project was to experimentally investigate the structure and dynamics of the streamwise vorticity in a plane mixing layer. The first part of this research program was intended to clarify whether the observed decrease in mean streamwise vorticity in the far-field of mixing layers is due primarily to the 'smearing' caused by vortex meander or to diffusion. Two-point velocity correlation measurements have been used to show that there is little spanwise meander of the large-scale streamwise vortical structure. The correlation measurements also indicate a large degree of transverse meander of the streamwise vorticity which is not surprising since the streamwise vorticity exists in the inclined braid region between the spanwise vortex core regions. The streamwise convection of the braid region thereby introduces an apparent transverse meander into measurements using stationary probes. These results corroborated with estimated secondary velocity profiles in which the streamwise vorticity produces a signature which was tracked in time.
Fibonacci anyons from Abelian bilayer quantum Hall states.
Vaezi, Abolhassan; Barkeshli, Maissam
2014-12-01
The possibility of realizing non-Abelian statistics and utilizing it for topological quantum computation (TQC) has generated widespread interest. However, the non-Abelian statistics that can be realized in most accessible proposals is not powerful enough for universal TQC. In this Letter, we consider a simple bilayer fractional quantum Hall system with the 1/3 Laughlin state in each layer. We show that interlayer tunneling can drive a transition to an exotic non-Abelian state that contains the famous "Fibonacci" anyon, whose non-Abelian statistics is powerful enough for universal TQC. Our analysis rests on startling agreements from a variety of distinct methods, including thin torus limits, effective field theories, and coupled wire constructions. We provide evidence that the transition can be continuous, at which point the charge gap remains open while the neutral gap closes. This raises the question of whether these exotic phases may have already been realized at ν=2/3 in bilayers, as past experiments may not have definitively ruled them out. PMID:25526149
Deligne-Beilinson cohomology and Abelian link invariants: Torsion case
Thuillier, F.
2009-12-15
For the Abelian Chern-Simons field theory, we consider the quantum functional integration over the Deligne-Beilinson cohomology classes and present an explicit path-integral nonperturbative computation of the Chern-Simons link invariants in SO(3){approx_equal}RP{sup 3}, a toy example of a 3-manifold with torsion.
Non-Abelian strings in supersymmetric Yang-Mills
Shifman, M.
2012-09-26
I give a broad review of novel phenomena discovered in certain Yang-Mills theories: non-Abelian strings and confined monopoles. Then I explain how these phenomena allow one to study strong dynamics of gauge theories in four dimensions from two-dimensional models emerging on the string world sheet.
Quantization of higher abelian gauge theory in generalized differential cohomology
NASA Astrophysics Data System (ADS)
Szabo, R.
We review and elaborate on some aspects of the quantization of certain classes of higher abelian gauge theories using techniques of generalized differential cohomology. Particular emphasis is placed on the examples of generalized Maxwell theory and Cheeger-Simons cohomology, and of Ramond-Ramond fields in Type II superstring theory and differential K-theory.
Probing Non-Abelian Statistics with Quasiparticle Interferometry
Bonderson, Parsa; Shtengel, Kirill; Slingerland, J.K.
2006-07-07
We examine interferometric experiments in systems that exhibit non-Abelian braiding statistics, expressing outcomes in terms of the modular S-matrix. In particular, this result applies to fractional quantum Hall interferometry, and we give a detailed treatment of the Read-Rezayi states, providing explicit predictions for the recently observed {nu}=12/5 plateau.
Two applications of potential vorticity thinking
NASA Technical Reports Server (NTRS)
Robinson, Walter A.
1987-01-01
The phenomena of dissipative destabilization of external Rossby waves and the acceleration of the zonal mean jet during baroclinic life cycles are described in terms of potential vorticity. The main principle of the potential temperature variations at rigid boundaries have the same effect on the interior flow as do sheets of potential vorticity located just within the boundaries. It is noted that the potential vorticity theory is useful for understanding the dynamical behavior of meterological phenomena.
NASA Astrophysics Data System (ADS)
Hamada, Yuta; Kawai, Hikaru; Oda, Kin-ya
2014-02-01
We consider a possibility that the Higgs field in the Standard Model (SM) serves as an inflaton when its value is around the Planck scale. We assume that the SM is valid up to an ultraviolet cutoff scale Λ , which is slightly below the Planck scale, and that the Higgs potential becomes almost flat above Λ . Contrary to the ordinary Higgs inflation scenario, we do not assume the huge non-minimal coupling, of O(10^4), of the Higgs field to the Ricci scalar. We find that Λ must be less than 5× 10^{17} {GeV} in order to explain the observed fluctuation of the cosmic microwave background, no matter how we extrapolate the Higgs potential above Λ . The scale 10^{17} {GeV} coincides with the perturbative string scale, which suggests that the SM is directly connected with string theory. For this to be true, the top quark mass is restricted to around 171 GeV, with which Λ can exceed 10^{17} {GeV}. As a concrete example of the potential above Λ , we propose a simple log-type potential. The predictions of this specific model for the e-foldings N_*=50-60 are consistent with the current observation, namely, the scalar spectral index is n_s=0.977hbox {-}0.983 and the tensor to scalar ratio 0
Gauge invariance of color confinement due to the dual Meissner effect caused by Abelian monopoles
Suzuki, Tsuneo; Hasegawa, Masayasu; Ishiguro, Katsuya; Koma, Yoshiaki; Sekido, Toru
2009-09-01
The mechanism of non-Abelian color confinement is studied in SU(2) lattice gauge theory in terms of the Abelian fields and monopoles extracted from non-Abelian link variables without adopting gauge fixing. First, the static quark-antiquark potential and force are computed with the Abelian and monopole Polyakov loop correlators, and the resulting string tensions are found to be identical to the non-Abelian string tension. These potentials also show the scaling behavior with respect to the change of lattice spacing. Second, the profile of the color-electric field between a quark and an antiquark is investigated with the Abelian and monopole Wilson loops. The color-electric field is squeezed into a flux tube due to monopole supercurrent with the same Abelian color direction. The parameters corresponding to the penetration and coherence lengths show the scaling behavior, and the ratio of these lengths, i.e., the Ginzburg-Landau parameter, indicates that the vacuum type is near the border of the type 1 and type 2 (dual) superconductors. These results are summarized in which the Abelian fundamental charge defined in an arbitrary color direction is confined inside a hadronic state by the dual Meissner effect. As the color-neutral state in any Abelian color direction corresponds to the physical color-singlet state, this effect explains non-Abelian color confinement and supports the existence of a gauge-invariant mechanism of color confinement due to the dual Meissner effect caused by Abelian monopoles.
An Integrated Higgs Force Theory
NASA Astrophysics Data System (ADS)
Colella, Antonio
2016-03-01
An Integrated Higgs force theory (IHFT) was based on 2 key requirement amplifications: a matter particle/Higgs force was one and inseparable; a matter particle/Higgs force bidirectionally condensed/evaporated from/to super force. These were basis of 5 theories: particle creation, baryogenesis, superpartner/quark decays, spontaneous symmetry breaking, and stellar black holes. Our universe's 129 matter/force particles contained 64 supersymmetric Higgs particles; 9 transient matter particles/Higgs forces decayed to 8 permanent matter particles/Higgs forces; mass was given to a matter particle by its Higgs force and gravitons; and sum of 8 Higgs force energies of 8 permanent matter particles was dark energy. An IHFT's essence is the intimate physical relationships between 8 theories. These theories are independent because physicists in one theory worked independently of physicists in the other seven. An IHFT's premise is without sacrificing their integrities, 8 independent existing theories are replaced by 8 interrelated amplified theories. Requirement amplifications provide interfaces between the 8 theories. Intimate relationships between 8 theories including the above 5 and string, Higgs forces, and Super Universe are described. The sorting category selected was F. PARTICLES AND FIELDS (e.g., F1 Higgs Physics, F10 Alternative Beyond the Standard Model Physics, F11 Dark Sector Theories and Searches, and F12 Particle Cosmology).
Aircraft trailing vortices: an introduction
NASA Astrophysics Data System (ADS)
Jacquin, Laurent
2005-05-01
Flow momentum that is deflected in a persistent way by a wing, or by another flow, becomes organised in coherent and energetic vortex structures. This phenomenon is briefly introduced here by comparison with other phenomena such as the production of vortices by impulsive forces (e.g. during animal flight), or the production of turbulence by jets. These considerations aim at underlining the fundamental nature of this strange mechanism, which is usually hidden behind engineering models produced by aerodynamic science. The control of these mechanisms, for applications to the safety of the airplanes for example, opens a vast multidisciplinary field of research. To cite this article: L. Jacquin, C. R. Physique 6 (2005).
Making sound vortices by metasurfaces
NASA Astrophysics Data System (ADS)
Ye, Liping; Qiu, Chunyin; Lu, Jiuyang; Tang, Kun; Jia, Han; Ke, Manzhu; Peng, Shasha; Liu, Zhengyou
2016-08-01
Based on the Huygens-Fresnel principle, a metasurface structure is designed to generate a sound vortex beam in airborne environment. The metasurface is constructed by a thin planar plate perforated with a circular array of deep subwavelength resonators with desired phase and amplitude responses. The metasurface approach in making sound vortices is validated well by full-wave simulations and experimental measurements. Potential applications of such artificial spiral beams can be anticipated, as exemplified experimentally by the torque effect exerting on an absorbing disk.
Vortices on surfaces with cylindrical ends
NASA Astrophysics Data System (ADS)
Venugopalan, Sushmita
2015-12-01
We consider Riemann surfaces obtained from nodal curves with infinite cylinders in the place of nodal and marked points, and study the space of finite energy vortices defined on these surfaces. To compactify the space of vortices, we need to consider stable vortices - these incorporate breaking of cylinders and sphere bubbling in the fibers. In this paper, we prove that the space of gauge equivalence classes of stable vortices representing a fixed equivariant homology class is compact and Hausdorff under the Gromov topology. We also show that this space is homeomorphic to the moduli space of quasimaps defined by Ciocan-Fontanine et al. (2014).
Quantized vortices around wavefront nodes, 2
NASA Technical Reports Server (NTRS)
Hirschfelder, J. O.; Goebel, C. J.; Bruch, L. W.
1974-01-01
Quantized vortices can occur around nodal points in wavefunctions. The derivation depends only on the wavefunction being single valued, continuous, and having continuous first derivatives. Since the derivation does not depend upon the dynamical equations, the quantized vortices are expected to occur for many types of waves such as electromagnetic and acoustic. Such vortices have appeared in the calculations of the H + H2 molecular collisions and play a role in the chemical kinetics. In a companion paper, it is shown that quantized vortices occur when optical waves are internally reflected from the face of a prism or particle beams are reflected from potential energy barriers.
Higgs boson decays in the littlest Higgs model
Gonzalez-Sprinberg, G.A.; Martinez, R.; Rodriguez, J.-Alexis
2005-02-01
We calculate the two body Higgs boson decays in the framework of the littlest Higgs model. The decay H{yields}{gamma}Z is computed at one-loop-level and, using previous results, we evaluate the branching fractions in the framework of the littlest Higgs model. A wide range of the space parameter of the model is considered and possible deviations from the standard model are explored.
Competing Abelian and non-Abelian topological orders in ν =1 /3 +1 /3 quantum Hall bilayers
NASA Astrophysics Data System (ADS)
Geraedts, Scott; Zaletel, Michael P.; Papić, Zlatko; Mong, Roger S. K.
2015-05-01
Bilayer quantum Hall systems, realized either in two separated wells or in the lowest two subbands of a wide quantum well, provide an experimentally realizable way to tune between competing quantum orders at the same filling fraction. Using newly developed density matrix renormalization group techniques combined with exact diagonalization, we return to the problem of quantum Hall bilayers at filling ν =1 /3 +1 /3 . We first consider the Coulomb interaction at bilayer separation d , bilayer tunneling energy ΔSAS, and individual layer width w , where we find a phase diagram which includes three competing Abelian phases: a bilayer Laughlin phase (two nearly decoupled ν =1 /3 layers), a bilayer spin-singlet phase, and a bilayer symmetric phase. We also study the order of the transitions between these phases. A variety of non-Abelian phases has also been proposed for these systems. While absent in the simplest phase diagram, by slightly modifying the interlayer repulsion we find a robust non-Abelian phase which we identify as the "interlayer-Pfaffian" phase. In addition to non-Abelian statistics similar to the Moore-Read state, it exhibits a novel form of bilayer-spin charge separation. Our results suggest that ν =1 /3 +1 /3 systems merit further experimental study.
Atmospheric Vortices in Shallow Convection.
NASA Astrophysics Data System (ADS)
Hess, G. D.; Spillane, K. T.; Lourensz, R. S.
1988-03-01
Observations of funnel clouds over Port Phillip Bay, Victoria, Australia, indicate that they occur during outbreaks of cool air from the Southern Ocean advecting over the relatively warm bay waters. These clouds act as tracers for shallow convection vortices with dynamics similar to large dust devils. The related phenomena of waterspouts and tornadoes differ from these vortices by requiring deep convection and downdraft and updraft interactions associated with rain processes.Deardorff (1978a) suggests that a necessary condition for the formation of dust devils is /L of the order of 100 or more, where h is the convective boundary layer height and L the Obukhov length. Calculations of /L over the bay and over land for the days of observation are consistent with this suggestion. They indicate that significant rotation may occur at /L as low as 50. This information, if confirmed, may make it possible to use boundary layer numerical models to forecast likely conditions of dust devil occurrence over mesoscale regions, which would be of benefit to pilots of light aircraft and helicopters.
Tunneling decay of false vortices
NASA Astrophysics Data System (ADS)
Lee, Bum-Hoon; Lee, Wonwoo; MacKenzie, Richard; Paranjape, M. B.; Yajnik, U. A.; Yeom, Dong-han
2013-10-01
We consider the decay of vortices trapped in the false vacuum of a theory of scalar electrodynamics in 2+1 dimensions. The potential is inspired by models with intermediate symmetry breaking to a metastable vacuum that completely breaks a U(1) symmetry, while in the true vacuum, the symmetry is unbroken. The false vacuum is unstable through the formation of true vacuum bubbles; however, the rate of decay can be extremely long. On the other hand, the false vacuum can contain metastable vortex solutions. These vortices contain the true vacuum inside in addition to a unit of magnetic flux and the appropriate topologically nontrivial false vacuum outside. We numerically establish the existence of vortex solutions which are classically stable; however, they can decay via tunneling. In general terms, they tunnel to a configuration which is a large, thin-walled vortex configuration that is now classically unstable to the expansion of its radius. We compute an estimate for the tunneling amplitude in the semiclassical approximation. We believe our analysis would be relevant to superconducting thin films or superfluids.
Goh, Hock-Seng; Goh, Hock-Seng; Krenke, Christopher A.
2007-07-25
We present a twin Higgs model based on left-right symmetry with a tree level quartic. This is made possible by extending the symmetry of the model to include two Z_2 parities, each of which is sufficient to protect the Higgs from getting a quadratically divergent mass squared. Although both parities are brokenexplicitly, the symmetries that protect the Higgs from getting a quadratically divergent mass are broken only collectively. The quadratic divergences of the Higgs mass are thus still protected at one loop. We find that the fine-tuning in this model is reduced substantially compared to the original left-right twin Higgs model. This mechanism can also be applied to the mirror twin Higgs model to get a significant reduction of the fine-tuning, while keeping the mirror photon massless.
The Higgs portal above threshold
NASA Astrophysics Data System (ADS)
Craig, Nathaniel; Lou, Hou Keong; McCullough, Matthew; Thalapillil, Arun
2016-02-01
The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at √{s}=14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.
Discussion on the complete-form vorticity equation and slantwise vorticity development
NASA Astrophysics Data System (ADS)
Wang, Xiuming; Zhou, Xiaogang; Tao, Zuyu; Liu, Hua
2016-02-01
The complete form of the vertical vorticity tendency equation (the complete-form vorticity equation) is derived from the Ertel potential vorticity equation to contain thermodynamic factors. In this study, a new complete-form vorticity equation, which has the same form as the original complete-form vorticity equation, is deduced from the absolute vorticity vector equation combined with the continuity equation and the expression of three-dimensional (3D) entropy gradient. By comparing the complete-form vorticity equation with the classical vertical vorticity equation, it is found that regardless of whether or not the isentropic surface is tilting, the two vorticity equations are in essence the same. The "baroclinic term" of the complete-form vorticity equation is exactly equal to the solenoidal term of the classical one, and there is a significant amount of cancellation between the two baroclinic items (the "slantwise term" and the horizontal vorticity change term) in the complete-form vorticity equation. In operational weather analysis, the tilt of the isentropic surface can be diagnosed according to the density of the isotherm on the upper-level isobaric map. For synoptic-scale motion, the vertical vorticity produced by the tilt of the isentropic surface is due to the contribution of atmospheric baroclinicity, which is measured by the solenoid. The 3D solenoid is parallel to the isentropic surface, so the more tilted the isentropic surface, the bigger the projection of the 3D solenoid in the vertical direction. The baroclinic contribution can be interpreted based on the PV thinking theory, but the relationship between the vorticity field and the potential vorticity field is not immediate.
On generating counter-rotating streamwise vortices
NASA Astrophysics Data System (ADS)
Winoto, S. H.; Mitsudharmadi, H.; Budiman, A. C.; Hasheminejad, S. M.; Nadesan, T.; Tandiono; Low, H. T.; Lee, T. S.
2015-09-01
Counter-rotating streamwise vortices are known to enhance the heat transfer rate from a surface and also to improve the aerodynamic performance of an aerofoil. In this paper, some methods to generate such counter-rotating vortices using different methods or physical conditions will be briefly considered and discussed.
Flute vortices in nonuniform magnetic fields
Yu, M.Y.; Shukla, P.K.; Varma, R.K.
1985-09-01
Localized double vortices associated with the flute modes are shown to exist. Special emphasis is given to the effect of the convective variation of the fluid magnetic moment. It is shown that the latter effect considerably modifies the existence regions of the vortices.
Optical vortices generation using the Wollaston prism
Kurzynowski, Piotr; Wozniak, Wladyslaw A.; Fraczek, Ewa
2006-10-20
A new setup of interferometers is proposed in which the set of specific optical markers - optical vortices - could be generated. The classical Mach-Zender two-beam interferometer has been modernized using the Wollaston prism. In this setup, the optical vortices could be obtained for a wide range of both beam parameters. The numerical analysis and experiments confirm our theoretical predictions.
Vortices in normal part of proximity system
Kogan, V. G.
2015-05-26
It is shown that the order parameter Δ induced in the normal part of superconductor-normal-superconductor proximity system is modulated in the magnetic field differently from vortices in bulk superconductors. Whereas Δ turns zero at vortex centers, the magnetic structure of these vortices differs from that of Abrikosov's.
Nonquasineutral electron vortices in nonuniform plasmas
Angus, J. R.; Richardson, A. S.; Swanekamp, S. B.; Schumer, J. W.; Ottinger, P. F.
2014-11-15
Electron vortices are observed in the numerical simulation of current carrying plasmas on fast time scales where the ion motion can be ignored. In plasmas with nonuniform density n, vortices drift in the B × ∇n direction with a speed that is on the order of the Hall speed. This provides a mechanism for magnetic field penetration into a plasma. Here, we consider strong vortices with rotation speeds V{sub ϕ} close to the speed of light c where the vortex size δ is on the order of the magnetic Debye length λ{sub B}=|B|/4πen and the vortex is thus nonquasineutral. Drifting vortices are typically studied using the electron magnetohydrodynamic model (EMHD), which ignores the displacement current and assumes quasineutrality. However, these assumptions are not strictly valid for drifting vortices when δ ≈ λ{sub B}. In this paper, 2D electron vortices in nonuniform plasmas are studied for the first time using a fully electromagnetic, collisionless fluid code. Relatively large amplitude oscillations with periods that correspond to high frequency extraordinary modes are observed in the average drift speed. The drift speed W is calculated by averaging the electron velocity field over the vorticity. Interestingly, the time-averaged W from these simulations matches very well with W from the much simpler EMHD simulations even for strong vortices with order unity charge density separation.
Draper, P.; Liu, T.; Wagner, C. E. M.; Wang, L.-T.; Zhang, H.
2011-03-24
We study a limit of the nearly Peccei-Quinn-symmetric next-to-minimal supersymmetric standard model possessing novel Higgs and dark matter (DM) properties. In this scenario, there naturally coexist three light singletlike particles: a scalar, a pseudoscalar, and a singlinolike DM candidate, all with masses of order 0.1-10 GeV. The decay of a standard model-like Higgs boson to pairs of the light scalars or pseudoscalars is generically suppressed, avoiding constraints from collider searches for these channels. For a certain parameter window annihilation into the light pseudoscalar and exchange of the light scalar with nucleons allow the singlino to achieve the correct relic density and a large direct-detection cross section consistent with the DM direct-detection experiments, CoGeNT and DAMA/LIBRA, preferred region simultaneously. This parameter space is consistent with experimental constraints from LEP, the Tevatron, ?, and flavor physics.
NASA Astrophysics Data System (ADS)
Arraut, Ivan
2015-09-01
The Higgs mechanism at the graviton level formulated as a Vainshtein mechanism in time domains implies that the extra-degrees of freedom become relevant depending on the direction of time (frame of reference) with respect to the preferred time direction (preferred frame) defined by the Stückelberg function T_0(r,t) which contains the information of the extra-degrees of freedom of the theory. In this manuscript, I make the general definition of the Higgs mechanism by analyzing the gauge symmetries of the action and the general form of the vacuum solutions for the graviton field. In general, the symmetry generators depending explicitly on the Stückelberg fields are broken at the vacuum level. These broken generators, define the number of Nambu-Goldstone bosons which will be eating up by the dynamical metric in order to become massive.
Relative equilibria of vortices in two dimensions.
Palmore, J I
1982-01-01
An old problem of the evolution of finitely many interacting point vortices in the plane is shown to be amenable to investigation by critical point theory in a way that is identical to the study of the planar n-body problem of celestial mechanics. For any choice of positive circulations of the vortices it is shown by critical point theory applied to Kirchhoff's function that there are many relative equilibria configurations. Each of these configurations gives rise to a stationary configuration of the vortices in a suitably chosen rotating coordinate system. A sharp lower bound on the number of stationary vortex configurations for the problem of point vortices interacting in the plane is given. The problem of point vortices in a circular disk is defined and it is shown that these estimates hold for stationary configurations of small size. PMID:16593155
Vorticity generation by contoured wall injectors
NASA Technical Reports Server (NTRS)
Waitz, Ian A.; Marble, Frank E.; Zukoski, Edward E.
1992-01-01
A class of contoured wall fuel injectors was designed to enable shock-enhancement of hypervelocity mixing for supersonic combustion ramjet applications. Previous studies of these geometries left unresolved questions concerning the relative importance of various axial vorticity sources in mixing the injectant with the freestream. The present study is a numerical simulation of two generic fuel injectors which is aimed at elucidating the relative roles of axial vorticity sources including: baroclinic torque through shock-impingement, cross-stream shear, turning of boundary layer vorticity, shock curvature, and diffusive flux. Both the magnitude of the circulation, and the location of vorticity with respect to the mixing interface were considered. Baroclinic torque and cross-stream shear were found to be most important in convectively mixing the injectant with the freestream, with the former providing for deposition of vorticity directly on the fuel/air interface.
Electrothermal blinking vortices for chaotic mixing
NASA Astrophysics Data System (ADS)
Loire, Sophie; Kauffmann, Paul; Gimenez, Paul; Meinhart, Carl; Mezic, Igor
2012-11-01
We present an experimental and theoretical study of electrothermal chaotic mixing using blinking of asymmetric 2D electrothermal vortices. Electrothermal flows are modelled with 2D finite element method using COMSOL software based on an enhanced electrothermal model. Velocities in top-view and side-view devices are measured by micro particle image velocimetry (μPIV). The experimentally reconstructed velocity profile shows a dramatic asymmetry between the two vortices, in good agreement with the FEM model. The separation line between the two vortices is shifted and tilted making the blinking vortices overlap. We use the mix-variance coefficient (MVC) on experimental particle detection data and numerical trajectory simulations to evaluate mixing at different scales including the layering of fluid interfaces by the flow, a keypoint for efficient mixing. The blinking vortices method greatly improve mixing efficiency. Theoretical, experimental and simulation results of the mixing process will be presented.
Schafer-Nameki, Sakura; Tamarit, Carlos; Torroba, Gonzalo; /SLAC /Santa Barbara, KITP
2010-08-26
We construct composite Higgs models admitting a weakly coupled Seiberg dual description. We focus on the possibility that only the up-type Higgs is an elementary field, while the down-type Higgs arises as a composite hadron. The model, based on a confining SQCD theory, breaks supersymmetry and electroweak symmetry dynamically and calculably. This simultaneously solves the {mu}/B{sub {mu}} problem and explains the smallness of the bottom and tau masses compared to the top mass. The proposal is then applied to a class of models where the same confining dynamics is used to generate the Standard Model flavor hierarchy by quark and lepton compositeness. This provides a unified framework for flavor, supersymmetry breaking and electroweak physics. The weakly coupled dual is used to explicitly compute the MSSM parameters in terms of a few microscopic couplings, giving interesting relations between the electroweak and soft parameters. The RG evolution down to the TeV scale is obtained and salient phenomenological predictions of this class of 'single-sector' models are discussed.
Quantum dissipative Higgs model
Amooghorban, Ehsan Mahdifar, Ali
2015-09-15
By using a continuum of oscillators as a reservoir, we present a classical and a quantum-mechanical treatment for the Higgs model in the presence of dissipation. In this base, a fully canonical approach is used to quantize the damped particle on a spherical surface under the action of a conservative central force, the conjugate momentum is defined and the Hamiltonian is derived. The equations of motion for the canonical variables and in turn the Langevin equation are obtained. It is shown that the dynamics of the dissipative Higgs model is not only determined by a projected susceptibility tensor that obeys the Kramers–Kronig relations and a noise operator but also the curvature of the spherical space. Due to the gnomonic projection from the spherical space to the tangent plane, the projected susceptibility displays anisotropic character in the tangent plane. To illuminate the effect of dissipation on the Higgs model, the transition rate between energy levels of the particle on the sphere is calculated. It is seen that appreciable probabilities for transition are possible only if the transition and reservoir’s oscillators frequencies to be nearly on resonance.
Possibility of early Higgs boson discovery in nonminimal Higgs sectors
Chang, Spencer; Evans, Jared A.; Luty, Markus A.
2011-11-01
Particle physics models with more than one Higgs boson occur in many frameworks for physics beyond the standard model, including supersymmetry, technicolor, composite Higgs, and ''little Higgs'' models. If the Higgs sector contains couplings stronger than electroweak gauge couplings, there will be heavy Higgs particles that decay to lighter Higgs particles plus heavy particles such as W, Z, and t. This motivates searches for final states involving multiple W, Z, t, and bb pairs. A two Higgs doublet model with custodial symmetry is a useful simplified model to describe many of these signals. The model can be parameterized by the physical Higgs masses and the mixing angles {alpha} and {beta}, so discovery or exclusion in this parameter space has a straightforward physical interpretation. We illustrate this with a detailed analysis of the process gg{yields}A followed by A{yields}hZ and h{yields}WW. For m{sub A}{approx_equal}330 GeV, m{sub h}{approx_equal}200 GeV we can get a 4.5{sigma} signal with 1 fb{sup -1} of integrated luminosity at the Large Hadron Collider.
Turbulent vortices in stratified fluids
NASA Technical Reports Server (NTRS)
Hecht, A. M.; Bilanin, A. J.; Hirsh, J. E.; Snedeker, R. S.
1979-01-01
In the present paper, calculations, made with the finite difference axisymmetric WAKE computer code, of the influence of turbulence and stratification on the behavior of vortex rings are compared with experimental data. Calculations, made with the two-dimensional version of the code, are used to study the behavior of vortex pairs in stably stratified atmospheres for a range of Froude numbers. Stratification is shown to have a profound effect on the radius of a vortex ring descending into a stably stratified fluid. The separation of the vortices of a vortex pair remains nearly constant or decreases monotonically with increasing penetration of a stably stratified fluid, depending on whether the stratification is discontinuous or linear. An analysis based on an energy balance is used to assess the maximum descent of a vortex pair in a stably stratified fluid.
Twist Helicity in Classical Vortices
NASA Astrophysics Data System (ADS)
Scheeler, Martin W.; Kedia, Hridesh; Kleckner, Dustin; Irvine, William T. M.
2015-11-01
Recent experimental work has demonstrated that a partial measure of fluid Helicity (the sum of linking and writhing of vortex tubes) is conserved even as those vortices undergo topology changing reconnections. Measuring the total Helicity, however, requires additional information about how the vortex lines are locally twisted inside the vortex core. To bridge this gap, we have developed a novel technique for experimentally measuring twist Helicity. Using this method, we are able to measure the production and eventual decay of twist for a variety of vortex evolutions. Remarkably, we observe twist dynamics capable of conserving total Helicity even in the presence of rapidly changing writhe. This work was supported by the NSF MRSEC shared facilities at the University of Chicago (DMR-0820054) and an NSF CAREER award (DMR-1351506). W.T.M.I. further acknowledges support from the A.P. Sloan Foundation and the Packard Foundation.
Non-Abelian Effects on D-Branes
Russo, Jorge G.
2008-07-28
We review different non-Abelian configurations of D-branes. We then extend the Myers dielectric effect to configurations with angular momentum. The resulting time-dependent N D0-brane bound states can be interpreted as describing rotating fuzzy ellipsoids. A similar solution exists also in the presence of a RR magnetic field, that we study in detail. We show that, for any finite N, above a certain critical angular momentum it is energetically more favorable for the bound state system to dissociate into an Abelian configuration of N D0-branes moving independently. We further study D-string configurations representing fuzzy funnels deformed by the magnetic field and by the rotational motion.
Braiding non-Abelian quasiholes in fractional quantum Hall states.
Wu, Yang-Le; Estienne, B; Regnault, N; Bernevig, B Andrei
2014-09-12
Quasiholes in certain fractional quantum Hall states are promising candidates for the experimental realization of non-Abelian anyons. They are assumed to be localized excitations, and to display non-Abelian statistics when sufficiently separated, but these properties have not been explicitly demonstrated except for the Moore-Read state. In this work, we apply the newly developed matrix product state technique to examine these exotic excitations. For the Moore-Read and the Z_{3} Read-Rezayi states, we estimate the quasihole radii, and determine the correlation lengths associated with the exponential convergence of the braiding statistics. We provide the first microscopic verification for the Fibonacci nature of the Z_{3} Read-Rezayi quasiholes. We also present evidence for the failure of plasma screening in the nonunitary Gaffnian wave function. PMID:25259996
Identifying non-Abelian topological order through minimal entangled states.
Zhu, W; Gong, S S; Haldane, F D M; Sheng, D N
2014-03-01
The topological order is encoded in the pattern of long-range quantum entanglements, which cannot be measured by any local observable. Here we perform an exact diagonalization study to establish the non-Abelian topological order for topological band models through entanglement entropy measurement. We focus on the quasiparticle statistics of the non-Abelian Moore-Read and Read-Rezayi states on the lattice models with bosonic particles. We identify multiple independent minimal entangled states (MESs) in the ground state manifold on a torus. The extracted modular S matrix from MESs faithfully demonstrates the Ising anyon or Fibonacci quasiparticle statistics, including the quasiparticle quantum dimensions and the fusion rules for such systems. These findings unambiguously demonstrate the topological nature of the quantum states for these flatband models without using the knowledge of model wave functions. PMID:24655269
Maximal Abelian gauge and a generalized BRST transformation
NASA Astrophysics Data System (ADS)
Deguchi, Shinichi; Pandey, Vipul Kumar; Mandal, Bhabani Prasad
2016-05-01
We apply a generalized Becchi-Rouet-Stora-Tyutin (BRST) formulation to establish a connection between the gauge-fixed SU (2) Yang-Mills (YM) theories formulated in the Lorenz gauge and in the Maximal Abelian (MA) gauge. It is shown that the generating functional corresponding to the Faddeev-Popov (FP) effective action in the MA gauge can be obtained from that in the Lorenz gauge by carrying out an appropriate finite and field-dependent BRST (FFBRST) transformation. In this procedure, the FP effective action in the MA gauge is found from that in the Lorenz gauge by incorporating the contribution of non-trivial Jacobian due to the FFBRST transformation of the path integral measure. The present FFBRST formulation might be useful to see how Abelian dominance in the MA gauge is realized in the Lorenz gauge.
Generation and Growth of Single Hairpin Vortices
NASA Astrophysics Data System (ADS)
Haji-Haidari, Ahmad
The behavior of selectively generated single hairpin vortices are examined within a laminar boundary layer environment over a range of Reynolds numbers, the hairpin vortices are experimentally generated by means of controlled fluid injection from a streamwise slot. Flow visualization using both dye and hydrogen bubble wire is employed in conjunction with hot film anemometry to investigate the growth characteristics and evolution of these single hairpin vortices. Qualitatively, it is established that hairpin vortices form by local destabilization at the interface between the low-speed fluid introduced through the slot and the higher speed boundary layer flow. Kinematical considerations of the hairpin vortex are established. It is observed that a hairpin vortex generally displays visualization and velocity signatures characteristic of those observed for a turbulent boundary layer. Hydrogen-bubble wire visualization results specifically indicate that hairpin vortices generate two purely turbulent-like flow patterns. The first is a low-speed streak pattern developing immediately adjacent to the surface due to surface interaction by the counter -rotating legs of the hairpin vortex; the second pattern is a turbulent pocket-like pattern farther removed from the surface. It is determined from the visualization data that hairpin vortices manifest the necessary flow characteristics which give rise to the regenerative and sustained process required for maintenance of turbulence. The regeneration and the growth process takes place through the formation of similar hairpin-like vortices by one of two means. The first is an inviscid lateral propagation of the initial disturbance which gives rise to outboard (subsidiary), vortices which cause the lateral spreading of the structure. A more complicated and eruptive process occurs by means of viscous-inviscid interactions which give rise to trailing vortices (secondary), which cause the streamwise elongation of the disturbance. A
An Exact Chiral Spin Liquid with Non-Abelian Anyons
Yao, Hong
2010-04-06
We establish the existence of a chiral spin liquid (CSL) as the exact ground state of the Kitaev model on a decorated honeycomb lattice, which is obtained by replacing each site in the familiar honeycomb lattice with a triangle. The CSL state spontaneously breaks time reversal symmetry but preserves other symmetries. There are two topologically distinct CSLs separated by a quantum critical point. Interestingly, vortex excitations in the topologically nontrivial (Chern number {+-}1) CSL obey non-Abelian statistics.
Linear resistivity from non-abelian black holes
NASA Astrophysics Data System (ADS)
Herzog, Christopher P.; Huang, Kuo-Wei; Vaz, Ricardo
2014-11-01
Starting with the holographic p-wave superconductor, we show how to obtain a finite DC conductivity through a non-abelian gauge transformation. The translational symmetry is preserved. We obtain phenomenological similarities with high temperature cuprate superconductors. Our results suggest that a lattice or impurities are not essential to produce a finite DC resistivity with a linear temperature dependence. An analogous field theory calculation for free fermions, presented in the appendix, indicates our results may be a special feature of strong interactions.
Non-Abelian anomalies on a curved space with torsion
Cognola, G.; Giacconi, P.
1989-05-15
Using path-integral methods and /zeta/-function regularization a nonperturbative derivation of non-Abelian-covariant and consistent anomalies on a curved space with torsion is given. All terms depending on torsion, that one has in the expression of the consistent anomaly, can be eliminated by adding suitable counterterms to the Lagrangian density. In this way, the well-known result of Bardeen is recovered. The so-called ''covariant anomaly'' will be discussed too.
Dawson, S.
1988-01-01
Experimental limits on light Higgs bosons (M/sub H/ < 5 GeV) are examined. Particular attention is paid to the process K H. It is shown that there may be an allowed window for light Higgs bosons between about 100 and 210 MeV. 13 refs., 2 figs.
Designer non-Abelian anyon platforms: from Majorana to Fibonacci
NASA Astrophysics Data System (ADS)
Alicea, Jason; Stern, Ady
2015-12-01
The emergence of non-Abelian anyons from large collections of interacting elementary particles is a conceptually beautiful phenomenon with important ramifications for fault-tolerant quantum computing. Over the last few decades the field has evolved from a highly theoretical subject to an active experimental area, particularly following proposals for trapping non-Abelian anyons in ‘engineered’ structures built from well-understood components. In this short overview we briefly tour the impressive progress that has taken place in the quest for the simplest type of non-Abelian anyon—defects binding Majorana zero modes—and then turn to similar strategies for pursuing more exotic excitations. Specifically, we describe how interfacing simple quantum Hall systems with conventional superconductors yields ‘parafermionic’ generalizations of Majorana modes and even Fibonacci anyons—the latter enabling fully fault tolerant universal quantum computation. We structure our treatment in a manner that unifies these topics in a coherent way. The ideas synthesized here spotlight largely uncharted experimental territory in the field of quantum Hall physics that appears ripe for discovery.
Non-Abelian discrete gauge symmetries in F-theory
NASA Astrophysics Data System (ADS)
Grimm, Thomas W.; Pugh, Tom G.; Regalado, Diego
2016-02-01
The presence of non-Abelian discrete gauge symmetries in four-dimensional F-theory compactifications is investigated. Such symmetries are shown to arise from seven-brane configurations in genuine F-theory settings without a weak string coupling description. Gauge fields on mutually non-local seven-branes are argued to gauge both R-R and NS-NS two-form bulk axions. The gauging is completed into a generalisation of the Heisenberg group with either additional seven-brane gauge fields or R-R bulk gauge fields. The former case relies on having seven-brane fluxes, while the latter case requires torsion cohomology and is analysed in detail through the M-theory dual. Remarkably, the M-theory reduction yields an Abelian theory that becomes non-Abelian when translated into the correct duality frame to perform the F-theory limit. The reduction shows that the gauge coupling function depends on the gauged scalars and transforms non-trivially as required for the groups encountered. This field dependence agrees with the expectations for the kinetic mixing of seven-branes and is unchanged if the gaugings are absent.
Universal attractor in a highly occupied non-Abelian plasma
NASA Astrophysics Data System (ADS)
Berges, J.; Boguslavski, K.; Schlichting, S.; Venugopalan, R.
2014-06-01
We study the thermalization process in highly occupied non-Abelian plasmas at weak coupling. The nonequilibrium dynamics of such systems is classical in nature and can be simulated with real-time lattice gauge theory techniques. We provide a detailed discussion of this framework and elaborate on the results reported in J. Berges, K. Boguslavski, S. Schlichting, and R. Venugopalan, Phys. Rev. D 89, 074011 (2014), 10.1103/PhysRevD.89.074011 along with novel findings. We demonstrate the emergence of universal attractor solutions, which govern the nonequilibrium evolution on large time scales both for nonexpanding and expanding non-Abelian plasmas. The turbulent attractor for a nonexpanding plasma drives the system close to thermal equilibrium on a time scale t ˜Q-1αs-7/4. The attractor solution for an expanding non-Abelian plasma leads to a strongly interacting albeit highly anisotropic system at the transition to the low-occupancy or quantum regime. This evolution in the classical regime is, within the uncertainties of our simulations, consistent with the "bottom up" thermalization scenario [R. Baier, A. H. Mueller, D. Schiff, and D. T. Son, Phys. Lett. B 502, 51 (2001), 10.1016/S0370-2693(01)00191-5]. While the focus of this paper is to understand the nonequilibrium dynamics in weak coupling asymptotics, we also discuss the relevance of our results for larger couplings in the early time dynamics of heavy ion collision experiments.
Fermion zero modes in the vortex background of a Chern-Simons-Higgs theory with a hidden sector
NASA Astrophysics Data System (ADS)
Lozano, Gustavo; Mohammadi, Azadeh; Schaposnik, Fidel A.
2015-11-01
In this paper we study a 2 + 1 dimensional system in which fermions are coupled to the self-dual topological vortex in U(1) × U(1) Chern-Simons theory, where both U(1) gauge symmetries are spontaneously broken. We consider two Abelian Higgs scalars with visible and hidden sectors coupled to a fermionic field through three interaction La-grangians, where one of them violates the fermion number. Using a fine tuning procedure, we could obtain the number of the fermionic zero modes which is equal to the absolute value of the sum of the vortex numbers in the visible and hidden sectors.
Escalante, Alberto Manuel-Cabrera, J.
2015-10-15
A detailed Faddeev–Jackiw quantization of an Abelian and non-Abelian exotic action for gravity in three dimensions is performed. We obtain for the theories under study the constraints, the gauge transformations, the generalized Faddeev–Jackiw brackets and we perform the counting of physical degrees of freedom. In addition, we compare our results with those found in the literature where the canonical analysis is developed, in particular, we show that both the generalized Faddeev–Jackiw brackets and Dirac’s brackets coincide to each other. Finally we discuss some remarks and prospects. - Highlights: • A detailed Faddeev–Jackiw analysis for exotic action of gravity is performed. • We show that Dirac’s brackets and Generalized [FJ] brackets are equivalent. • Without fixing the gauge exotic action is a non-commutative theory. • The fundamental gauge transformations of the theory are found. • Dirac and Faddeev–Jackiw approaches are compared.
Measurement of vorticity diffusion by NMR microscopy.
Brown, Jennifer R; Callaghan, Paul T
2010-05-01
In a Newtonian fluid, vorticity diffuses at a rate determined by the kinematic viscosity. Here we use rapid NMR velocimetry, based on a RARE sequence, to image the time-dependent velocity field on startup of a fluid-filled cylinder and therefore measure the diffusion of vorticity. The results are consistent with the solution to the vorticity diffusion equation where the angular velocity on the outside surface of the fluid, at the cylinder's rotating wall, is fixed. This method is a means of measuring kinematic viscosity for low viscosity fluids without the need to measure stress. PMID:20189854
Vortices and turbulence in trapped atomic condensates
White, Angela C.; Anderson, Brian P.; Bagnato, Vanderlei S.
2014-01-01
After more than a decade of experiments generating and studying the physics of quantized vortices in atomic gas Bose–Einstein condensates, research is beginning to focus on the roles of vortices in quantum turbulence, as well as other measures of quantum turbulence in atomic condensates. Such research directions have the potential to uncover new insights into quantum turbulence, vortices, and superfluidity and also explore the similarities and differences between quantum and classical turbulence in entirely new settings. Here we present a critical assessment of theoretical and experimental studies in this emerging field of quantum turbulence in atomic condensates. PMID:24704880
Vortices in magnetically coupled superconducting layered systems
Mints, Roman G.; Kogan, Vladimir G.; Clem, John R.
2000-01-01
Pancake vortices in stacks of thin superconducting films or layers are considered. It is stressed that in the absence of Josephson coupling topological restrictions upon possible configurations of vortices are removed and various examples of structures forbidden in bulk superconductors are given. In particular, it is shown that vortices may skip surface layers in samples of less than a certain size R{sub c} which might be macroscopic. The Josephson coupling suppresses R{sub c} estimates. (c) 2000 The American Physical Society.
Vorticity in heavy-ion collisions
NASA Astrophysics Data System (ADS)
Deng, Wei-Tian; Huang, Xu-Guang
2016-06-01
We study the event-by-event generation of flow vorticity in the BNL Relativistic Heavy Ion Collider Au +Au collisions and CERN Large Hadron Collider Pb +Pb collisions by using the hijing model. Different definitions of the vorticity field and velocity field are considered. A variety of properties of the vorticity are explored, including the impact parameter dependence, the collision energy dependence, the spatial distribution, the event-by-event fluctuation of the magnitude and azimuthal direction, and the time evolution. In addition, the spatial distribution of the flow helicity is also studied.
Hollow vortices in weakly compressible flows
NASA Astrophysics Data System (ADS)
Krishnamurthy, Vikas; Crowdy, Darren
2014-11-01
In a two-dimensional, inviscid and steady fluid flow, hollow vortices are bounded regions of constant pressure with non-zero circulation. It is known that for an infinite row of incompressible hollow vortices, analytical solutions for the flow field and the shape of the hollow vortex boundary can be obtained using conformal mapping methods. In this talk, we show how to derive analytical expressions for a weakly compressible hollow vortex row. This is done by introducing a new method based on the Imai-Lamla formula. We will also touch upon how to extend these results to a von-Karman street of hollow vortices.
Hollow vortices in weakly compressible flows
NASA Astrophysics Data System (ADS)
Krishnamurthy, Vikas; Crowdy, Darren
2015-11-01
In a two-dimensional, inviscid and steady fluid flow, hollow vortices are bounded regions of constant pressure with non-zero circulation. It is known that for an infinite row of incompressible hollow vortices, analytical solutions for the flow field and the shape of the hollow vortex boundary can be obtained using conformal mapping methods. In this talk, we show how to derive analytical expressions for a weakly compressible hollow vortex row. This is done by introducing a new method based on the Imai-Lamla formula. We will also touch upon how to extend these results to a von-Karman street of hollow vortices.
Transonic interactions of unsteady vortical flows
NASA Technical Reports Server (NTRS)
Mccroskey, W. J.; Srinivasan, G. R.
1984-01-01
Unsteady interactions of strong concentrated vortices, distributed gusts, and sharp-edged gusts with stationary airfoils were analyzed in two-dimensional transonic flow. A simple and efficient method for introducing such vortical disturbances was implemented in numerical codes that range from inviscid transonic small disturbance to thin-layer Navier Stokes. The numerical results demonstrate the large distortions in the overall flow field and in the surface air loads that are produced by various vortical interactions. The results of the different codes are in excellent qualitative agreement, but, as might expected, the transonic small-disturbance calculations are deficient in the important region near the leading edge.
Non-Abelian Aharonov-Bohm effect with the time-dependent gauge fields
NASA Astrophysics Data System (ADS)
Hosseini Mansoori, Seyed Ali; Mirza, Behrouz
2016-04-01
We investigate the non-Abelian Aharonov-Bohm (AB) effect for time-dependent gauge fields. We prove that the non-Abelian AB phase shift related to time-dependent gauge fields, in which the electric and magnetic fields are written in the adjoint representation of SU (N) generators, vanishes up to the first order expansion of the phase factor. Therefore, the flux quantization in a superconductor ring does not appear in the time-dependent Abelian or non-Abelian AB effect.
NASA Astrophysics Data System (ADS)
Khan, Mayukh; Teo, Jeffrey; Hughes, Taylor
2014-03-01
We consider bosonic abelian Fractional Quantum Hall (FQH) and Fractional Quantum Spin Hall (FQSH) states with edge theories drawn from the ADE Kac Moody algebras at level 1 . This set of systems have `anyonic' symmetries that leave braiding and fusion invariant Remarkably, the group of anyonic symmetries for this class of models is isomorphic to the symmetries of the Dynkin diagrams of the particular ADE Lie Algebra under consideration. The triality symmetry of the Dynkin diagram of so(8) leads to the largest anyonic symmetry group S3 (the permutation group on 3 elements). Each element of the anyonic symmetry group corresponds to a distinct way of gapping out the edge (i.e., each element corresponds to a Lagrangian subgroup). Junctions between two distinct gapped edges host non abelian twist defects with quantum dimensions (> 1). In the case of so(8) we have more exotic twist defects with non-abelian fusion. We acknowledge support from the U.S. Department of Energy, Division of Materials Sciences under Award No. DE-FG02- 07ER46453 (MK, TLH) and the Simons Foundation (JT).
Atmospheric Vortices near Guadalupe Island
NASA Technical Reports Server (NTRS)
2000-01-01
These MISR images from June 11, 2000 (Terra orbit 2569) demonstrate a turbulent atmospheric flow pattern known as the von Karman vortex street. This phenomenon is named after aerodynamicist Theodore von Karman, who theoretically derived the conditions under which it occurs. The alternating double row of vortices can form in the wake of an obstacle, in this instance the eastern Pacific island of Guadalupe. The rugged terrain of this volcanic Mexican island reaches a maximum elevation of 1.3 kilometers. The island is about 35 kilometers long and is located 260 kilometers west of Baja California.
The vortex pattern is made visible by the marine stratocumulus clouds around Guadalupe Island. The upper image is a color view obtained by MISR's vertical-viewing (nadir) camera. North is toward the left. The orientation of the vortex street indicates that the wind direction is from lower left to upper right (northwest to southeast). The areas within the vortex centers tend to be clear because the rotating motions induce a vertical wind component that can break up the cloud deck.
The lower view is a stereo picture generated from data acquired by MISR's fore- and aft-viewing 70-degree cameras. A 3-D effect is obtained by viewing the image with red/blue glasses and placing the red filter over your left eye. Note how the downwelling atmospheric motion (change in elevation from high to low) is accompanied by a clearing in the center of the first vortex. As the vortices propagate downstream, their rotational velocities weaken. As a consequence, the induced vertical motion and cloud-clearing effect weakens as well.
Theodore von Karman was a Professor of Aeronautics at Caltech and Director of Caltech's Guggenheim Aeronautical Laboratory from 1930-1949. He was one of the principal founders of the Jet Propulsion Laboratory.
MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra
NASA Technical Reports Server (NTRS)
Harrison, D. E.; Holland, W. R.
1981-01-01
A mean vorticity budget analysis is presented of Holland's (1978) numerical ocean general circulation experiment. The stable budgets are compared with classical circulation theory to emphasize the ways in which the mesoscale motions of the model alter (or leave unaltered) classical vorticity balances. The basinwide meridional transports of vorticity by the mean flow and by the mesoscale flow in the mean are evaluated to establish the role(s) of the mesoscale in the larger scale equilibrium vorticity transports. The vorticity equation for this model fluid system is presented and the budget analysis method is described. Vorticity budgets over the selected regions and on a larger scale are given, and a summary of budget results is provided along with remarks about the utility of this type of analysis.
Analytic vortex solutions on compact hyperbolic surfaces
NASA Astrophysics Data System (ADS)
Maldonado, Rafael; Manton, Nicholas S.
2015-06-01
We construct, for the first time, abelian Higgs vortices on certain compact surfaces of constant negative curvature. Such surfaces are represented by a tessellation of the hyperbolic plane by regular polygons. The Higgs field is given implicitly in terms of Schwarz triangle functions and analytic solutions are available for certain highly symmetric configurations.
Exotic Higgs decay via charged Higgs
NASA Astrophysics Data System (ADS)
Li, Tong; Su, Shufang
2015-11-01
The most common search channel for heavy neutral Higgses in models with an extension of the Standard Model Higgs sector is A/H 0 → ττ which becomes ineffective when new decay modes of A/H 0 open. In this paper, we analyzed two such channels involving charged Higgses in the final states: A/H 0 → W ± H ∓ and H 0 → H + H -. With the consequent decay of H ± → τν, we found that the limits for σ × BR( gg → A/H 0 → W ± H ∓) × BR( H ± → τν) vary from 30 to 10fb for m A/ H 0 between 300 and 1000GeV for 95% C.L. exclusion, and about 80 to 30 fb for 5 σ discovery. For H + H - mode, 95% C.L. limits on σ × BR( gg → H 0 → H + H -) × BR2( H ± → τν) vary from 9 to 4 fb for m H 0 between 400 and 1000 GeV, while the 5σ reach is about 20 to 10 fb. We further interpret the cross section limits in the Type II 2HDM parameter space. While A → W ± H ∓ offers great sensitivity in both sin( β - α) versus tan β and m A versus tan β parameter space, H 0 → H + H - can cover most of the parameter space for H 0. Reach in H 0 → W ± H ∓ is more limited, especially for m H 0 > 2 m H ± . It is, however, complementary to H 0 → H + H - when BR( H 0 → H + H -) is accidentally suppressed.
Tornadoes and other atmospheric vortices
NASA Technical Reports Server (NTRS)
Deissler, R. G.
1976-01-01
The growth of random vortices in an atmosphere with buoyant instability and vertical wind shear is studied along with the velocities in a single gravity-driven vortex; a frictionless adiabatic model which is supported by laboratory experiments is first considered. The effects of axial drag, heat transfer, and precipitation-induced downdrafts are then calculated. Heat transfer and axial drag tend to have stabilizing effects; they reduce the downdrafts of updrafts due to buoyancy. It is found that downdrafts or tornadic magnitude might occur in negatively-buoyant columns. The radial-inflow velocity required to maintain a given maximum tangential velocity in a tornado is determined by using a turbulent vortex model. Conditions under which radial-inflow velocities become sufficiently large to produce tangential velocities of tornadic magnitude are determined. The radial velocities in the outer regions, as well as the tangential velocities in the inner regions may be large enough to cause damage. The surface boundary layer, which is a region where large radial inflows can occur, is studied, and the thickness of the radial-inflow friction layer is estimated. A tornado model which involves a rotating parent cloud, as well as buoyancy and precipitation effects, is discussed.
Combustion enhancement by axial vortices
NASA Astrophysics Data System (ADS)
Gutmark, E.; Schadow, K. C.; Parr, T. P.; Parr, D. M.; Wilson, K. J.
1987-06-01
A tapered slot jet was studied experimentally in nonreacting and reacting tests using hot-wire anemometry, water-tunnel flow visualization, and Planar Laser Induced Fluorescence (PLIF). The tapered slot jet is a modified elliptic jet which has a conical contraction leading to its outlet. The added contraction changes the entire flow field. The jet spread in the major axis plane is larger than in the minor axis plane, which is the opposite behavior of an elliptic jet. Consequently, no axes switching, typical to an elliptic jet, is observed. The turbulence amplification in the jet core is higher than in circular and elliptic jets. The different behavior is attributed to the change in flow direction, inside the nozzle, from the conical section to the slot outlet. During this transition, the flow acquires angular momentum thereby generating axial vorticity. The influence of the contraction angle and the outlet aspect ratio were investigated. The effect of the augmented turbulence on reactive flow was tested in a premixed flame. The combustion rate was augmented in both the core and edges of the flame relative to a circular burner.
Vorticity matching in superfluid helium
NASA Astrophysics Data System (ADS)
Samuels, David C.
1991-12-01
Recent experiments have rekindled interest in high Reynolds number flows using superfluid helium. In a continuing series of experiments, the flow of helium II through various devices (smooth pipes, corrugated pipes, valves, venturies, turbine flowmeters, and coanda flowmeters for example) was investigated. In all cases, the measured values (typically, mass flow rates and pressure drops) were found to be well described by classical relations for high Reynolds flows. This is unexpected since helium II consists of two interpenetrating fluids; one fluid with nonzero viscosity (the normal fluid) and one with zero viscosity (the superfluid). Only the normal fluid component should directly obey classical relations. Since the experiments listed above only measure the external behavior of the flow (i.e., pressure drops over devices), there is a great deal of room for interpretation of their results. One possible interpretation is that in turbulent flows the normal fluid and the superfluid velocity fields are somehow 'locked' together, presumably by the mutual friction force between the superfluid vortex filaments and the normal fluid. We refer to this locking together of the two fluids as 'vorticity matching.'
Vortices in simulations of solar surface convection
NASA Astrophysics Data System (ADS)
Moll, R.; Cameron, R. H.; Schüssler, M.
2011-09-01
We report on the occurrence of small-scale vortices in simulations of the convective solar surface. Using an eigenanalysis of the velocity gradient tensor, we find the subset of high-vorticity regions in which the plasma is swirling. The swirling regions form an unsteady, tangled network of filaments in the turbulent downflow lanes. Near-surface vertical vortices are underdense and cause a local depression of the optical surface. They are potentially observable as bright points in the dark intergranular lanes. Vortex features typically exist for a few minutes, during which they are moved and twisted by the motion of the ambient plasma. The bigger vortices found in the simulations are possibly, but not necessarily, related to observations of granular-scale spiraling pathlines in "cork animations" or feature tracking. Three movies are available in electronic form at http://www.aanda.org
Partially composite Higgs in supersymmetry
NASA Astrophysics Data System (ADS)
Kitano, Ryuichiro; Luty, Markus A.; Nakai, Yuichiro
2012-08-01
We propose a framework for natural breaking of electroweak symmetry in supersymmetric models, where elementary Higgs fields are semi-perturbatively coupled to a strong superconformal sector. The Higgs VEVs break conformal symmetry in the strong sector at the TeV scale, and the strong sector in turn gives important contributions to the Higgs potential, giving rise to a kind of Higgs bootstrap. A Higgs with mass 125 GeV can be accommodated without any fine tuning. A Higgsino mass of order the Higgs mass is also dynamically generated in these models. The masses in the strong sector generically violate custodial symmetry, and a good precision electroweak fit requires tuning of order ~ 10%. The strong sector has an approximately supersymmetric spectrum of hadrons at the TeV scale that can be observed by looking for a peak in the WZ invariant mass distribution, as well as final states containing multiple W, Z, and Higgs bosons. The models also generically predict large corrections (either enhancement or suppression) to the h → γγ width.
Electroweak Baryogenesis and Higgs Properties
Cohen, Timothy; Morrissey, David E.; Pierce, Aaron; /Michigan U., MCTP
2012-03-13
We explore the connection between the strength of the electroweak phase transition and the properties of the Higgs boson. Our interest is in regions of parameter space that can realize electroweak baryogenesis. We do so in a simplified framework in which a single Higgs field couples to new scalar fields charged under SU(3){sub c} by way of the Higgs portal. Such new scalars can make the electroweak phase transition more strongly first-order, while contributing to the effective Higgs boson couplings to gluons and photons through loop effects. For Higgs boson masses in the range 115 {approx}< m{sub h} {approx}< 130 GeV, whenever the phase transition becomes strong enough for successful electroweak baryogenesis, we find that Higgs boson properties are modified by an amount observable by the LHC. We also discuss the baryogenesis window of the minimal supersymmetric standard model (MSSM), which appears to be under tension. Furthermore, we argue that the discovery of a Higgs boson with standard model-like couplings to gluons and photons will rule out electroweak baryogenesis in the MSSM.
Rotationally induced vortices in optical cavity modes
NASA Astrophysics Data System (ADS)
Habraken, Steven J. M.; Nienhuis, Gerard
2009-09-01
We show that vortices appear in the modes of an astigmatic optical cavity when it is put into rotation about its optical axis. We study the properties of these vortices and discuss numerical results for a specific realization of such a set-up. Our method is exact up to first order in the time-dependent paraxial approximation and involves bosonic ladder operators in the spirit of the quantum-mechanical harmonic oscillator.
Atmospheric Columnar Vortices (Paper 7R0104)
NASA Astrophysics Data System (ADS)
Snow, John T.
1987-04-01
The family of atmospheric columnar vortices includes tornadoes, waterspouts, firewhirls, dust devils and a variety of other whirlwinds. Each member of the family is characterized by the presence of a relatively tall, concentrated vortical core. Descriptions of such swirling flows are inherently complex, reflecting the presence of a multiplicity of length and velocity scales. In many cases, the flow is both three-dimensional and unsteady.
Compactlike kinks and vortices in generalized models
Bazeia, D.; Hora, E. da; Menezes, R.; Oliveira, H. P. de; Santos, C. dos
2010-06-15
This work deals with the presence of topological defects in k-field models, where the dynamics is generalized to include higher order power in the kinetic term. We investigate kinks in (1, 1) dimensions and vortices in (2, 1) dimensions, focusing on some specific features of the solutions. In particular, we show how the kinks and vortices change to compactlike solutions, controlled by the parameter used to introduce the generalized models.
NASA Astrophysics Data System (ADS)
Barnard, James; Gherghetta, Tony; Ray, Tirtha Sankar; Spray, Andrew
2015-01-01
Composite Higgs models can trivially satisfy precision-electroweak and flavour constraints by simply having a large spontaneous symmetry breaking scale, f ≳ 10 TeV. This produces a `split' spectrum, where the strong sector resonances have masses greater than 10 TeV and are separated from the pseudo Nambu-Goldstone bosons, which remain near the electroweak scale. Even though a tuning of order 10-4 is required to obtain the observed Higgs boson mass, the big hierarchy problem remains mostly solved. Intriguingly, models with a fully-composite right-handed top quark also exhibit improved gauge coupling unification. By restricting ourselves to models which preserve these features we find that the symmetry breaking scale cannot be arbitrarily raised, leading to an upper bound f ≲ 100-1000 TeV. This implies that the resonances may be accessible at future colliders, or indirectly via rare-decay experiments. Dark matter is identified with a pseudo Nambu-Goldstone boson, and we show that the smallest coset space containing a stable, scalar singlet and an unbroken SU(5) symmetry is SU(7) /SU(6) × U(1). The colour-triplet pseudo Nambu-Goldstone boson also contained in this coset space is metastable due to a residual symmetry. It can decay via a displaced vertex when produced at colliders, leading to a distinctive signal of unnaturalness.
Birkedal, Andreas; Noble, Andrew; Perelstein, Maxim; Spray, Andrew
2006-08-01
The introduction of T parity dramatically improves the consistency of little Higgs models with precision electroweak data, and renders the lightest T-odd particle (LTP) stable. In the littlest Higgs model with T parity, the LTP is typically the T-odd heavy photon, which is weakly interacting and can play the role of dark matter. We analyze the relic abundance of the heavy photon, including its coannihilations with other T-odd particles, and map out the regions of the parameter space where it can account for the observed dark matter. We evaluate the prospects for direct and indirect discovery of the heavy photon dark matter. The direct detection rates are quite low and a substantial improvement in experimental sensitivity would be required for observation. A substantial flux of energetic gamma rays is produced in the annihilation of the heavy photons in the galactic halo. This flux can be observed by the GLAST telescope, and, if the distribution of dark matter in the halo is favorable, by ground-based telescope arrays such as VERITAS and HESS.
On Higgs inflation and naturalness
NASA Astrophysics Data System (ADS)
Burgess, C. P.; Lee, H. M.; Trott, Michael
2010-07-01
We reexamine recent claims that Einstein-frame scattering in the Higgs inflation model is unitary above the cut-off energy Λ ≃ M p /ξ. We show explicitly how unitarity problems arise in both the Einstein and Jordan frames of the theory. In a covariant gauge they arise from non-minimal Higgs self-couplings, which cannot be removed by field redefinitions because the target space is not flat. In unitary gauge, where there is only a single scalar which can be redefined to achieve canonical kinetic terms, the unitarity problems arise through non-minimal Higgs-gauge couplings.
Cuenca Almenar, Cristobal; /UC, Irvine
2010-01-01
Advanced analysis techniques together with increasing data samples are bringing the sensitivity of CDF to the Higgs boson very close to the SM predictions. These improvements translate into more stringent exclusions of parameter space in BSM Higgs sectors and of the SM mass range. The CDF Collaboration has a very active program on Higgs searches that comprises most accessible production mechanisms and decay channels in {bar p}p collisions at {radical}s = 1.96 TeV. This contribution will also review the combination of the different channels, data samples and analysis techinques that currently produces one of the most exciting experimental results in our field.
Potential Vorticity as a Diagnostic of Transport into the Martian Polar Vortices
NASA Astrophysics Data System (ADS)
McConnochie, Timothy H.; Conrath, B. J.; Gierasch, P. J.; Banfield, D.; Smith, M. D.
2009-09-01
Polar vortices dominate the dynamics of the winter mid- and polar latitudes in the martian atmosphere as well as in the terrestrial stratosphere. Polar vortices have also been observed on Venus (Taylor, 2002), Jupiter (Orton, 2002), Saturn (Fletcher, 2008), and Titan (Teanby, 2008). Potential vorticity is the analysis quantity of choice for the terrestrial polar vortices because its vertical component distills the most important features of the wind and temperature fields into a single scalar variable; because it is a conserved tracer under adiabatic conditions; because it serves as the medium for Rossby waves; and because steep potential vorticity gradients are observed to be correlated with steep gradients in the concentrations of chemical species. Using potential vorticity derived from Mars Global Surveyor Thermal Emission Spectrometer (TES) temperature soundings, we find that the northern martian winter polar vortex, just like its terrestrial conterpart, is bounded by a region of very steep potential vorticity gradients and is surrounded by a "surf zone", a region of low potential vorticity and very low potential vorticity gradients. The surf zone concept, as first described for the terrestrial stratosphere by McIntyre and Palmer (1983), implies persistent Rossby wave breaking. In the vicinity of the northern polar vortex, the TES data set provides some examples of local gradient reversals that are suggestive of wave breaking. There is also one case of large-scale wave breaking accompanied by an abrupt polar warming. We also find that the martian southern polar vortex lacks a distinct boundary between the polar vortex and a surf zone. Instead, the potential vorticity field is highly disorganized with local gradient reversals throughout the middle and polar latitudes. In the zonal mean, the southern winter potential vorticity gradient ends up being relatively uniform, although it is somewhat enhanced near 60 degrees latitude.
Veneziano amplitudes, spin chains and Abelian reduction of QCD
NASA Astrophysics Data System (ADS)
Kholodenko, Arkady
2009-05-01
Although QCD can be treated perturbatively in the high energy limit, lower energies require uses of nonperturbative methods such as ADS/CFT and/or Abelian reduction. These methods are not equivalent. While the first is restricted to supersymmetric Yang-Mills model with number of colors going to infinity, the second is not restricted by requirements of supersymmetry and is designed to work in the physically realistic limit of a finite number of colors. In this paper we provide arguments in favor of the Abelian reduction methods. This is achieved by further developing results of our recent works re-analyzing Veneziano and Veneziano-like amplitudes and the models associated with these amplitudes. It is shown, that the obtained new partition function for these amplitudes can be mapped exactly into that for the Polychronakos-Frahm (P-F) spin chain model recoverable from the Richardon-Gaudin (R-G) XXX spin chain model originally designed for treatments of the BCS-type superconductivity. Because of this, it is demonstrated that the obtained mapping is compatible with the method of Abelian reduction. The R-G model is recovered from the asymptotic (WKB-type) solutions of the rational Knizhnik-Zamolodchikov (K-Z) equation. Linear independence of these solutions is controlled by determinants whose explicit form (up to a constant) coincides with Veneziano (or Veneziano-like) amplitudes. In the simplest case, the determinantal conditions coincide with those discovered by Kummer in the 19th century. Kummer's results admit physical interpretation by relating determinantal formula(s) to Veneziano-like amplitudes. Furthermore, these amplitudes can be interpreted as Poisson-Dirichlet distributions playing a central role in the stochastic theory of random coagulation-fragmentation processes. Such an interpretation is complementary to that known for the Lund model widely used for the description of coagulation-fragmentation processes in QCD.
Abelian tensor hierarchy in 4D, N = 1 superspace
NASA Astrophysics Data System (ADS)
Becker, Katrin; Becker, Melanie; Linch, William D.; Robbins, Daniel
2016-03-01
With the goal of constructing the supersymmetric action for all fields, massless and massive, obtained by Kaluza-Klein compactification from type II theory or M-theory in a closed form, we embed the (Abelian) tensor hierarchy of p-forms in four-dimensional, N =1superspaceandconstructitsChern-Simons-likeinvariants. Whenspecializedtothe case in which the tensors arise from a higher-dimensional theory, the invariants may be interpreted as higher-dimensional Chern-Simons forms reduced to four dimensions. As an application of the formalism, we construct the eleven-dimensional Chern-Simons form in terms of four-dimensional, N = 1 superfields.
On spectral synthesis on zero-dimensional Abelian groups
Platonov, S S
2013-09-30
Let G be a zero-dimensional locally compact Abelian group all of whose elements are compact, and let C(G) be the space of all complex-valued continuous functions on G. A closed linear subspace H⊆C(G) is said to be an invariant subspace if it is invariant with respect to the translations τ{sub y}:f(x)↦f(x+y), y∈G. In the paper, it is proved that any invariant subspace H admits spectral synthesis, that is, H coincides with the closed linear span of the characters of G belonging to H. Bibliography: 25 titles.
The non-Abelian gauge theory of matrix big bangs
NASA Astrophysics Data System (ADS)
O'Loughlin, Martin; Seri, Lorenzo
2010-07-01
We study at the classical and quantum mechanical level the time-dependent Yang-Mills theory that one obtains via the generalisation of discrete light-cone quantization to singular homogeneous plane waves. The non-Abelian nature of this theory is known to be important for physics near the singularity, at least as far as the number of degrees of freedom is concerned. We will show that the quartic interaction is always subleading as one approaches the singularity and that close enough to t = 0 the evolution is driven by the diverging tachyonic mass term. The evolution towards asymptotically flat space-time also reveals some surprising features.
Abelian cosmic string in the Starobinsky model of gravity
NASA Astrophysics Data System (ADS)
Morais Graça, J. P.
2016-03-01
In this paper, I analyze numerically the behaviour of the solutions corresponding to an Abelian string in the framework of the Starobinsky model. The role played by the quadratic term in the Lagrangian density f(R)=R+η {R}2 of this model is emphasized and the results are compared with the corresponding ones obtained in the framework of Einstein’s theory of gravity. I have found that the angular deficit generated by the string is lowered as the η parameter increases, allowing a well-behaved spacetime for a large range of values of the symmetry-breaking scale.
Non-Abelian gauge invariance and the infrared approximation
Cho, H.h.; Fried, H.M.; Grandou, T.
1988-02-15
Two constructions are given of infrared approximations, defined by a nonlocal configuration-space restrictions, which preserve the local, non-Abelian gauge invariance of SU(N) two-dimensional QCD (QCD/sub 2/). These continuum infrared methods are used to estimate the quenched order parameter
The Abelian Sandpile Model on a Random Binary Tree
NASA Astrophysics Data System (ADS)
Redig, F.; Ruszel, W. M.; Saada, E.
2012-06-01
We study the abelian sandpile model on a random binary tree. Using a transfer matrix approach introduced by Dhar and Majumdar, we prove exponential decay of correlations, and in a small supercritical region (i.e., where the branching process survives with positive probability) exponential decay of avalanche sizes. This shows a phase transition phenomenon between exponential decay and power law decay of avalanche sizes. Our main technical tools are: (1) A recursion for the ratio between the numbers of weakly and strongly allowed configurations which is proved to have a well-defined stochastic solution; (2) quenched and annealed estimates of the eigenvalues of a product of n random transfer matrices.
Non-Abelian monopole in the parameter space of point-like interactions
NASA Astrophysics Data System (ADS)
Ohya, Satoshi
2014-12-01
We study non-Abelian geometric phase in N = 2 supersymmetric quantum mechanics for a free particle on a circle with two point-like interactions at antipodal points. We show that non-Abelian Berry's connection is that of SU(2) magnetic monopole discovered by Moody, Shapere and Wilczek in the context of adiabatic decoupling limit of diatomic molecule.
Supersymmetric Higgs Bosons and Beyond
Carena, Marcela; Kong, Kyoungchul; Ponton, Eduardo; Zurita, Jose; /Fermilab /Buenos Aires U.
2010-08-26
We consider supersymmetric models that include particles beyond the Minimal Supersymmetric Standard Model (MSSM) with masses in the TeV range, and that couple significantly to the MSSM Higgs sector. We perform a model-independent analysis of the spectrum and couplings of the MSSM Higgs fields, based on an effective theory of the MSSM degrees of freedom. The tree-level mass of the lightest CP-even state can easily be above the LEP bound of 114 GeV, thus allowing for a relatively light spectrum of superpartners, restricted only by direct searches. The Higgs spectrum and couplings can be significantly modified compared to the MSSM ones, often allowing for interesting new decay modes. We also observe that the gluon fusion production cross section of the SM-like Higgs can be enhanced with respect to both the Standard Model and the MSSM.
Lincoln, Don
2014-08-12
Fermilab scientist Don Lincoln describes the nature of the Higgs boson. Several large experimental groups are hot on the trail of this elusive subatomic particle which is thought to explain the origins of particle mass.
NASA Astrophysics Data System (ADS)
Barceló, Roberto; Masip, Manuel
2008-11-01
We discuss a little Higgs scenario that introduces below the TeV scale just the two minimal ingredients of these models, a vectorlike T quark and a singlet component (implying anomalous couplings) in the Higgs field, together with a pseudoscalar singlet η. In the model, which is a variation of Schmaltz’s simplest little Higgs model, all the extra vector bosons are much heavier than the T quark. In the Yukawa sector the global symmetry is approximate, implying a single large coupling per flavor, whereas in the scalar sector it is only broken at the loop level. We obtain the one-loop effective potential and show that it provides acceptable masses for the Higgs h and for the singlet η with no need for an extra μ term. We find that mη can be larger than mh/2, which would forbid the (otherwise dominant) decay mode h→ηη.
Lincoln, Don
2011-07-07
Fermilab scientist Don Lincoln describes the nature of the Higgs boson. Several large experimental groups are hot on the trail of this elusive subatomic particle which is thought to explain the origins of particle mass.
Numerical simulation of baroclinic Jovian vortices
NASA Astrophysics Data System (ADS)
Achterberg, R. K.; Ingersoll, A. P.
1994-02-01
We examine the evolution of baroclinic vortices in a time-dependent, nonlinear numerical model of a Jovian atmosphere. The model uses a normal-mode expansion in the vertical, using the barotropic and first two baroclinic modes. Results for the stability of baroclinic vortices on an f plane in the absence of a mean zonal flow are similar to results of Earth vortex models, although the presence of a fluid interior on the Jovian planets shifts the stability boundaries to smaller length scales. The presence of a barotropic mean zonal flow in the interior stabilizes vortices against instability and significantly modifies the finite amplitude form of baroclinic instabilities. The effect of a zonal flow on a form of barotropic instability produces periodic oscillations in the latitude and longitude of the vortex as observed at the level of the cloud tops. This instability may explain some, but not all, observations of longitudinal oscillations of vortices on the outer planets. Oscillations in aspect ratio and orientation of stable vortices in a zonal shear flow are observed in this baroclinic model, as in simpler two-dimensional models. Such oscillations are also observed in the atmospheres of Jupiter and Neptune. The meridional propagation and decay of vortices on a beta plane is inhibited by the presence of a mean zonal flow. The direction of propagation of a vortex relative to the mean zonal flow depends upon the sign of the meridional potential vorticity gradient; combined with observations of vortex drift rates, this may provide a constraint on model assumption for the flow in the deep interior of the Jovian planets.
A procedure for calculating vorticity boundary conditions in the stream-function-vorticity method
NASA Astrophysics Data System (ADS)
MacKinnon, R. J.; Carey, G. F.; Murray, P.
1990-01-01
A superconvergent projection formula is constructed for determining vorticity boundary data in the stream-function-vorticity method. The approach applies to both straight and curved boundaries and can be used for either finite-element or finite-difference computations.
Higgs Physics in Supersymmetric Models
NASA Astrophysics Data System (ADS)
Jaiswal, Prerit
Standard Model (SM) successfully describes the particle spectrum in nature and the interaction between these particles using gauge symmetries. However, in order to give masses to these particles, the electroweak gauge symmetry must be broken. In the SM, this is achieved through the Higgs mechanism where a scalar Higgs field acquires a vacuum expectation value. It is well known that the presence of a scalar field in the SM leads to a hierarchy problem, and therefore the SM by itself can not be the fundamental theory of nature. A well-motivated extension of the SM which addresses this problem is the Minimal Supersymmetric Standard Model (MSSM). The Higgs sector in the MSSM has a rich phenomenology and its predictions can be tested at colliders. In this thesis, I will describe three examples in supersymmetric models where the Higgs phenomenology is significantly different from that in SM. The first example is the MSSM with large tan
NASA Astrophysics Data System (ADS)
Sardanashvily, G. A.
2014-12-01
We consider a classical gauge theory on a principal fiber bundle P → X in the case where its structure group G is reduced to a subgroup H in the presence of classical Higgs fields described by global sections of the quotient fiber bundle P/H → X. We show that matter fields with the exact symmetry group H in such a theory are described by sections of the composition fiber bundle Y → P/H → X, where Y → P/H is the fiber bundle with the structure group H, and the Lagrangian of these sections is factored by virtue of the vertical covariant differential determined by a connection on the fiber bundle Y → P/H.
Initial Circulation and Peak Vorticity Behavior of Vortices Shed from Airfoil Vortex Generators
NASA Technical Reports Server (NTRS)
Wendt, Bruce J.; Biesiadny, Tom (Technical Monitor)
2001-01-01
An extensive parametric study of vortices shed from airfoil vortex generators has been conducted to determine the dependence of initial vortex circulation and peak vorticity on elements of the airfoil geometry and impinging flow conditions. These elements include the airfoil angle of attack, chord length, span, aspect ratio, local boundary layer thickness, and free stream Mach number. In addition, the influence of airfoil-to-airfoil spacing on the circulation and peak vorticity has been examined for pairs of co-rotating and counter-rotating vortices. The vortex generators were symmetric airfoils having a NACA-0012 cross-sectional profile. These airfoils were mounted either in isolation, or in pairs, on the surface of a straight pipe. The turbulent boundary layer thickness to pipe radius ratio was about 17 percent. The circulation and peak vorticity data were derived from cross-plane velocity measurements acquired with a seven-hole probe at one chord-length downstream of the airfoil trailing edge location. The circulation is observed to be proportional to the free-stream Mach number, the angle-of-attack, and the span-to-boundary layer thickness ratio. With these parameters held constant, the circulation is observed to fall off in monotonic fashion with increasing airfoil aspect ratio. The peak vorticity is also observed to be proportional to the free-stream Mach number, the airfoil angle-of-attack, and the span-to-boundary layer thickness ratio. Unlike circulation, however, the peak vorticity is observed to increase with increasing aspect ratio, reaching a peak value at an aspect ratio of about 2.0 before falling off again at higher values of aspect ratio. Co-rotating vortices shed from closely spaced pairs of airfoils have values of circulation and peak vorticity under those values found for vortices shed from isolated airfoils of the same geometry. Conversely, counter-rotating vortices show enhanced values of circulation and peak vorticity when compared to values
Interaction of vortices with flexible piezoelectric beams
NASA Astrophysics Data System (ADS)
Goushcha, Oleg; Akaydin, Huseyin Dogus; Elvin, Niell; Andreopoulos, Yiannis
2012-11-01
A cantilever piezoelectric beam immersed in a flow is used to harvest fluidic energy. Pressure distribution induced by naturally present vortices in a turbulent fluid flow can force the beam to oscillate producing electrical output. Maximizing the power output of such an electromechanical fluidic system is a challenge. In order to understand the behavior of the beam in a fluid flow where vortices of different scales are present, an experimental facility was set up to study the interaction of individual vortices with the beam. In our set up, vortex rings produced by an audio speaker travel at specific distances from the beam or impinge on it, with a frequency varied up to the natural frequency of the beam. Depending on this frequency both constructive and destructive interactions between the vortices and the beam are observed. Vortices traveling over the beam with a frequency multiple of the natural frequency of the beam cause the beam to resonate and larger deflection amplitudes are observed compared to excitation from a single vortex. PIV is used to compute the flow field and circulation of each vortex and estimate the effect of pressure distribution on the beam deflection. Sponsored by NSF Grant: CBET #1033117.
NASA Astrophysics Data System (ADS)
Yang, W.; Meng, H.
1999-11-01
The dynamics of vortex structures in the wake of surface-mounted trapezoidal tab at Re=600 based on tab height was studied in detail using time-series, 2D particle image velocimetry. From a total of over 20,000 PIV realizations acquired in x-y, x-z, and y-z planes, we successfully identified vortex structures using the methods proposed by Jeong and Hussain (JFM, vol 285, 1995) and proposed by Chong, Perry, and Cantwell (Phys. Fluids A2, 1990), and cross-checked them with conventional velocity subtraction. Similar to prior measurement at Re=2080, secondary vortices, reverse vortices, and tertiary vortices were observed frequently in the present study. Higher PIV spatial resolution and higher temporal resolution (relative to the flow periodicity) allow us to investigate these dynamical phenomena in much greater detail and confidence. Furthermore, y-z measurements demonstrate that hairpin vortex legs, taking the shape of streamwise vortices, pair with their neighbor counterparts while traveling downstream, and possibly merge with each other. Circulation distribution of the hairpin vortex heads along the x direction shows that it increases at the very near-tab region with the help of pressure induced counter-rotating vortex pairs, but gradually decreases very slowly with the increasing downstream distance, indicating that hairpin vortices are long-lived vortex structures.
3D Vortices in Protoplanetary Disks
NASA Astrophysics Data System (ADS)
Kamal, Samy; Barranco, Joseph; Marcus, Philip
2010-11-01
Like the atmosphere of Jupiter, protoplanetary disks (thin disks of gas & dust in orbit around newly-formed stars) are characterized by rapid rotation and intense shear, inspiring proposals that disks may also be populated with long-lived, robust storms analogous to the Great Red Spot. Such vortices may play key roles in the formation of stars and planets by transporting angular momentum, as well as trapping and concentrating dust grains, seeding the formation of planetesimals, the "building blocks" of planets. In our previous work (Barranco & Marcus 2005), we showed via numerical simulation (with an anelastic spectral code) that vortices near the midplane of the disk suffer an antisymmetric instability and are destroyed. However, internal gravity waves propagate away from the midplane, amplify and break, creating bands of vorticity that roll-up into new long-lived, stable vortices above and below the midplane. We will present new results on 3D vortex dynamics in protoplanetary disks, exploring the role of factors unique to this context: the Coriolis parameter f, the shear rate σ, and the Brunt-Väisälä frequency N are all of the same order of magnitude. In the region around the midplane N
On discrete symmetries for a whole Abelian model
NASA Astrophysics Data System (ADS)
Chauca, J.; Doria, R.
2012-10-01
Considering the whole concept applied to gauge theory a nonlinear abelian model is derived. A next step is to understand on the model properties. At this work, it will be devoted to discrete symmetries. For this, we will work based in two fields reference systems. This whole gauge symmetry allows to be analyzed through different sets which are the constructor basis {Dμ,Xiμ} and the physical basis {GμI}. Taking as fields reference system the diagonalized spin-1 sector, P, C, T and PCT symmetries are analyzed. They show that under this systemic model there are conservation laws driven for the parts and for the whole. It develops the meaning of whole-parity, field-parity and so on. However it is the whole symmetry that rules. This means that usually forbidden particles as pseudovector photons can be introduced through such whole abelian system. As result, one notices that the fields whole {GμI} manifest a quanta diversity. It involves particles with different spins, masses and discrete quantum numbers under a same gauge symmetry. It says that without violating PCT symmetry different possibilities on discrete symmetries can be accommodated.
On discrete symmetries for a whole Abelian model
Chauca, J.; Doria, R.
2012-09-24
Considering the whole concept applied to gauge theory a nonlinear abelian model is derived. A next step is to understand on the model properties. At this work, it will be devoted to discrete symmetries. For this, we will work based in two fields reference systems. This whole gauge symmetry allows to be analyzed through different sets which are the constructor basis {l_brace}D{sub {mu}},X{sup i}{sub {mu}}{r_brace} and the physical basis {l_brace}G{sub {mu}I}{r_brace}. Taking as fields reference system the diagonalized spin-1 sector, P, C, T and PCT symmetries are analyzed. They show that under this systemic model there are conservation laws driven for the parts and for the whole. It develops the meaning of whole-parity, field-parity and so on. However it is the whole symmetry that rules. This means that usually forbidden particles as pseudovector photons can be introduced through such whole abelian system. As result, one notices that the fields whole {l_brace}G{sub {mu}I}{r_brace} manifest a quanta diversity. It involves particles with different spins, masses and discrete quantum numbers under a same gauge symmetry. It says that without violating PCT symmetry different possibilities on discrete symmetries can be accommodated.
Non-Abelian gauge redundancy and entropic ambiguities
NASA Astrophysics Data System (ADS)
Balachandran, A. P.; de Queiroz, A. R.; Vaidya, S.
2015-04-01
The von Neumann entropy of a generic quantum state is not unique unless the state can be uniquely decomposed as a sum of extremal or pure states. Therefore one reaches the remarkable possibility that there may be many entropies for a given state. We show that this happens if the GNS representation (of the algebra of observables in some quantum state) is reducible, and some representations in the decomposition occur with non-trivial degeneracy. This ambiguity in entropy, which can occur at zero temperature, can often be traced to a gauge symmetry emergent from the non-trivial topological character of the configuration space of the underlying system. We also establish the analogue of an H-theorem for this entropy by showing that its evolution is Markovian, determined by a stochastic matrix. After demonstrating this entropy ambiguity for the simple example of the algebra of 2 × 2 matrices, we argue that the degeneracies in the GNS representation can be interpreted as an emergent broken gauge symmetry, and play an important role in the analysis of emergent entropy due to non-Abelian anomalies. We work out the simplest situation with such non-Abelian symmetry, that of an ethylene molecule.
On spectral synthesis on element-wise compact Abelian groups
NASA Astrophysics Data System (ADS)
Platonov, S. S.
2015-08-01
Let G be an arbitrary locally compact Abelian group and let C(G) be the space of all continuous complex-valued functions on G. A closed linear subspace \\mathscr H\\subseteq C(G) is referred to as an invariant subspace if it is invariant with respect to the shifts τ_y\\colon f(x)\\mapsto f(xy), y\\in G. By definition, an invariant subspace \\mathscr H\\subseteq C(G) admits strict spectral synthesis if \\mathscr H coincides with the closure in C(G) of the linear span of all characters of G belonging to \\mathscr H. We say that strict spectral synthesis holds in the space C(G) on G if every invariant subspace \\mathscr H\\subseteq C(G) admits strict spectral synthesis. An element x of a topological group G is said to be compact if x is contained in some compact subgroup of G. A group G is said to be element-wise compact if all elements of G are compact. The main result of the paper is the proof of the fact that strict spectral synthesis holds in C(G) for a locally compact Abelian group G if and only if G is element-wise compact. Bibliography: 14 titles.
Matrix product states and the non-Abelian rotor model
NASA Astrophysics Data System (ADS)
Milsted, Ashley
2016-04-01
We use uniform matrix product states to study the (1 +1 )D O (2 ) and O (4 ) rotor models, which are equivalent to the Kogut-Susskind formulation of matter-free non-Abelian lattice gauge theory on a "Hawaiian earring" graph for U (1 ) and S U (2 ), respectively. Applying tangent space methods to obtain ground states and determine the mass gap and the β function, we find excellent agreement with known results, locating the Berezinskii-Kosterlitz-Thouless transition for O (2 ) and successfully entering the asymptotic weak-coupling regime for O (4 ). To obtain a finite local Hilbert space, we truncate in the space of generalized Fourier modes of the gauge group, comparing the effects of different cutoff values. We find that higher modes become important in the crossover and weak-coupling regimes of the non-Abelian theory, where entanglement also suddenly increases. This could have important consequences for tensor network state studies of Yang-Mills on higher-dimensional graphs.
Cubic and Quartic Higgs Couplings of Higgs Potentials and CP Phases
NASA Astrophysics Data System (ADS)
Song, You; Yan, Qi-Shu; Zhao, Xiao-Ran
2016-06-01
We derive cubic and quartic couplings of the Higgs singlet extension of the SM and the two Higgs doublet model. We also examine the number of CP violated couplings in a model with n Higgs doublet model and a model with ns Higgs singlets and nd Higgs doublets. We conclude that in order to reconstruct the Higgs potential with multi Higgs fields at the LHC and future colliders, to detect the cubic/quartic couplings is necessary. Supported by the Natural Science Foundation of China under Grant Nos. 11175251 and 11575005
Vorticity, defects and correlations in active turbulence
Thampi, Sumesh P.; Golestanian, Ramin; Yeomans, Julia M.
2014-01-01
We describe a numerical investigation of a continuum model of an active nematic, concentrating on the regime of active turbulence. Results are presented for the effect of three parameters, activity, elastic constant and rotational diffusion constant, on the order parameter and flow fields. Defects and distortions in the director field act as sources of vorticity, and thus vorticity is strongly correlated to the director field. In particular, the characteristic length of decay of vorticity and order parameter correlations is controlled by the defect density. By contrast, the decay of velocity correlations is determined by a balance between activity and dissipation. We highlight the role of microscopic flow generation mechanisms in determining the flow patterns and characteristic scales of active turbulence and contrast the behaviour of extensile and contractile active nematics. PMID:25332382
Characterization of reconnecting vortices in superfluid helium.
Bewley, Gregory P; Paoletti, Matthew S; Sreenivasan, Katepalli R; Lathrop, Daniel P
2008-09-16
When two vortices cross, each of them breaks into two parts and exchanges part of itself for part of the other. This process, called vortex reconnection, occurs in classical and superfluids, and in magnetized plasmas and superconductors. We present the first experimental observations of reconnection between quantized vortices in superfluid helium. We do so by imaging micrometer-sized solid hydrogen particles trapped on quantized vortex cores and by inferring the occurrence of reconnection from the motions of groups of recoiling particles. We show that the distance separating particles on the just-reconnected vortex lines grows as a power law in time. The average value of the scaling exponent is approximately 1/2, consistent with the self-similar evolution of the vortices. PMID:18768790
Vortical mechanism for generation of astrophysical jets
NASA Astrophysics Data System (ADS)
Abrahamyan, M. G.
2008-04-01
A vortical mechanism for generation of astrophysical jets is proposed based on exact solutions of the hydrodynamic equations with a generalized Rankine vortex. It is shown that the development of a Rankine vortex in the polar layer of a rotating gravitating body creates longitudinal fluxes of matter that converge toward the vortex trunk, providing an exponential growth in the angular rotation velocity of the trunk and a pressure drop on its axis. The increased rotational velocity of the vortex trunk and the on-axis pressure drop cease when the discontinuity in the azimuthal velocity at the surface of the trunk reaches the sound speed. During this time, ever deeper layers of the gravitating body are brought into the vortical motion, while the longitudinal velocity of the flow along the vortex trunk builds up, producing jet outflows of mass from its surface. The resulting vortices are essentially dissipationless.
How center vortices break chiral symmetry
NASA Astrophysics Data System (ADS)
Faber, Manfried; Höllwieser, Roman
2016-01-01
We investigate the chiral properties of near-zero modes for thick classical center vortices in SU(2) lattice gauge theory as examples of the phenomena which may arise in a vortex vacuum. In particular we analyze the creation of near-zero modes from would-be zero modes of various topological charge contributions from center vortices. We show that classical colorful spherical vortex and instanton ensembles have almost identical Dirac spectra and the low-lying eigenmodes from spherical vortices show all characteristic properties for chiral symmetry breaking. We further show that also vortex intersections are able to give rise to a finite density of near-zero modes, leading to chiral symmetry breaking via the Banks-Casher formula. We discuss the mechanism by which center vortex fluxes contribute to chiral symmetry breaking.
Potential Vorticity Analysis of Tropical Cyclone Intensification.
NASA Astrophysics Data System (ADS)
Molinari, John; Skubis, Steven; Vollaro, David; Alsheimer, Frank; Willoughby, Hugh E.
1998-08-01
The interaction of marginal Tropical Storm Danny (1985) with an upper-tropospheric positive potential vorticity anomaly was examined. The intensification mechanism proposed earlier for mature Hurricane Elena appears to be valid for Danny as well, despite significant differences in the synoptic-scale environment and in the stage of the tropical cyclone prior to the interaction. Both storms experienced rapid pressure falls as a relatively small-scale positive upper potential vorticity anomaly began to superpose with the low-level tropical cyclone center.The interaction is described in terms of a complex interplay between vertical wind shear, diabatic heating, and mutual advection among vortices at and below the level of the outflow anticyclone. Despite this complexity, the superposition principle appears to be conceptually useful to describe the intensification of tropical cyclones during such interactions.
A Note on Trapping Moving Vortices
NASA Technical Reports Server (NTRS)
Kao, Hsiao C.
2000-01-01
The topic of stationary configurations of point vortices, also known as vortex equilibrium, has received considerable attention in recent years. By observing numerical results, it is found that a "counterpart" of this system also exists, in which moving vortices may be "trapped" by an inlet-like device to form a stationary pattern with no translational motion. After an intuitive explanation for the process, vortex trajectory maps based on numerical results are presented. These maps exhibit two stationary points under the present conditions, which are the focal points of vortex trajectories. A vortex upstream of these points, if within a certain offset range, will move towards these points spontaneously and be captured there. This proposed device is also capable of trapping spinning vortex pairs and triads. It is possible to impose a uniform stream at infinity, as long as the flow field is still dominated by the moving vortices.
Measurements of Supersonic Wing Tip Vortices
NASA Technical Reports Server (NTRS)
Smart, Michael K.; Kalkhoran, Iraj M.; Benston, James
1994-01-01
An experimental survey of supersonic wing tip vortices has been conducted at Mach 2.5 using small performed 2.25 chords down-stream of a semi-span rectangular wing at angle of attack of 5 and 10 degrees. The main objective of the experiments was to determine the Mach number, flow angularity and total pressure distribution in the core region of supersonic wing tip vortices. A secondary aim was to demonstrate the feasibility of using cone probes calibrated with a numerical flow solver to measure flow characteristics at supersonic speeds. Results showed that the numerically generated calibration curves can be used for 4-hole cone probes, but were not sufficiently accurate for conventional 5-hole probes due to nose bluntness effects. Combination of 4-hole cone probe measurements with independent pitot pressure measurements indicated a significant Mach number and total pressure deficit in the core regions of supersonic wing tip vortices, combined with an asymmetric 'Burger like' swirl distribution.
Vorticity and divergence in the solar photosphere
NASA Technical Reports Server (NTRS)
Wang, YI; Noyes, Robert W.; Tarbell, Theodore D.; Title, Alan M.
1995-01-01
We have studied an outstanding sequence of continuum images of the solar granulation from Pic du Midi Observatory. We have calculated the horizontal vector flow field using a correlation tracking algorithm, and from this determined three scalar field: the vertical component of the curl; the horizontal divergence; and the horizontal flow speed. The divergence field has substantially longer coherence time and more power than does the curl field. Statistically, curl is better correlated with regions of negative divergence - that is, the vertical vorticity is higher in downflow regions, suggesting excess vorticity in intergranular lanes. The average value of the divergence is largest (i.e., outflow is largest) where the horizontal speed is large; we associate these regions with exploding granules. A numerical simulation of general convection also shows similar statistical differences between curl and divergence. Some individual small bright points in the granulation pattern show large local vorticities.
Characterization of reconnecting vortices in superfluid helium
Bewley, Gregory P.; Paoletti, Matthew S.; Sreenivasan, Katepalli R.; Lathrop, Daniel P.
2008-01-01
When two vortices cross, each of them breaks into two parts and exchanges part of itself for part of the other. This process, called vortex reconnection, occurs in classical and superfluids, and in magnetized plasmas and superconductors. We present the first experimental observations of reconnection between quantized vortices in superfluid helium. We do so by imaging micrometer-sized solid hydrogen particles trapped on quantized vortex cores and by inferring the occurrence of reconnection from the motions of groups of recoiling particles. We show that the distance separating particles on the just-reconnected vortex lines grows as a power law in time. The average value of the scaling exponent is approximately ½, consistent with the self-similar evolution of the vortices. PMID:18768790
Identification of vortices in complex flows
NASA Astrophysics Data System (ADS)
Chakraborty, P.; Balachandar, S.; Adrian, R. J.
2007-12-01
Dating back to Leonardo da Vinci's famous sketches of vortices in turbulent flows, fluid dynamicists for over five centuries have continued to visualize and interpret complex flows in terms of motion of vortices. Nevertheless, much debate surrounds the question of how to unambiguously define vortices in complex flows. This debate has resulted in the availability of many vortex identification criteria---mathematical statements of what constitutes a vortex. Here we review the popularly used local or point- wise vortex identification criteria. Based on local flow kinematics, we describe a unified framework to interpret the similarities and differences in the usage of these criteria. We discuss the limitations on the applicability of these criteria when there is a significant component of vortex interactions. Finally, we provide guidelines for applying these criteria to geophysical flows.
Longitudinal vortices imbedded in turbulent boundary layers
NASA Astrophysics Data System (ADS)
Mehta, R. D.; Shabaka, I. M. M.; Shibl, A.; Bradshaw, P.
1983-01-01
The attenuation of skew-induced longitudinal vortices by turbulent or viscous stresses is studied for the case of pure, artificially-generated longitudinal vortices entrained into initially two-dimensional boundary layers in nominally zero pressure gradients. Three types of vortex-boundary interactions are studied in detail: (1) an isolated vortex in a two-dimensional boundary layer; (2) a vortex pair in a turbulent boundary layer with the common flow between the vortices moving away from the surface; (3) a vortex pair in a boundary layer with the common flow moving towards the surface. Detailed mean flow and turbulence measurements are made, showing that the eddy viscosities defined for the different shear-stress components behave in different and complicated ways. Terms in the Reynolds stress transport equations, notably the triple products that effect turbulent diffusion of Reynolds stress, also fail to obey simple rules.
T-Parity in Little Higgs Models
Krohn, David
2008-11-23
We examine quantum anomalies in the context of little Higgs theories. In particular, we investigate the restrictions imposed upon little Higgs models when one requires an exact T-parity. Applications to LHC phenomenology are briefly discussed.
Twin Higgs mechanism and a composite Higgs boson
NASA Astrophysics Data System (ADS)
Low, Matthew; Tesi, Andrea; Wang, Lian-Tao
2015-05-01
We combine the twin Higgs mechanism with the paradigm of composite Higgs models. In this class of models the Higgs is a pseudo-Nambu-Goldstone boson from a strongly coupled sector near the TeV scale, and it is additionally protected by a discrete symmetry due to the twin mechanism. We discuss the model-building issues associated with this setup and quantify the tuning needed to achieve the correct electroweak vacuum and the Higgs mass. In contrast to standard composite Higgs models, the lightest resonance associated with the top sector is the uncolored mirror top, while the colored top partners can be made parameterically heavier without extra tuning. In some cases, the vector resonances are predicted to lie in the multi-TeV range. We present models where the resonances—both fermions and vectors—being heavier alleviates the pressure on naturalness coming from direct searches demonstrating that theories with low tuning may survive constraints from the Large Hadron Collider.
Aerodynamics and vortical structures in hovering fruitflies
NASA Astrophysics Data System (ADS)
Meng, Xue Guang; Sun, Mao
2015-03-01
We measure the wing kinematics and morphological parameters of seven freely hovering fruitflies and numerically compute the flows of the flapping wings. The computed mean lift approximately equals to the measured weight and the mean horizontal force is approximately zero, validating the computational model. Because of the very small relative velocity of the wing, the mean lift coefficient required to support the weight is rather large, around 1.8, and the Reynolds number of the wing is low, around 100. How such a large lift is produced at such a low Reynolds number is explained by combining the wing motion data, the computed vortical structures, and the theory of vorticity dynamics. It has been shown that two unsteady mechanisms are responsible for the high lift. One is referred as to "fast pitching-up rotation": at the start of an up- or downstroke when the wing has very small speed, it fast pitches down to a small angle of attack, and then, when its speed is higher, it fast pitches up to the angle it normally uses. When the wing pitches up while moving forward, large vorticity is produced and sheds at the trailing edge, and vorticity of opposite sign is produced near the leading edge and on the upper surface, resulting in a large time rate of change of the first moment of vorticity (or fluid impulse), hence a large aerodynamic force. The other is the well known "delayed stall" mechanism: in the mid-portion of the up- or downstroke the wing moves at large angle of attack (about 45 deg) and the leading-edge-vortex (LEV) moves with the wing; thus, the vortex ring, formed by the LEV, the tip vortices, and the starting vortex, expands in size continuously, producing a large time rate of change of fluid impulse or a large aerodynamic force.
Vorticity Confinement Applied to Turbulent Wing Tip Vortices for Wake-Integral Drag Prediction
NASA Astrophysics Data System (ADS)
Pierson, Kristopher; Povitsky, Alex
2013-11-01
In the current study the vorticity confinement (VC) approach was applied to tip vortices shed by edges of stationary wings in order to predict induced drag by far-field integration in Trefftz plane. The VC parameter was evaluated first by application to convection of vortices in 2-D uniform flow and then to tip vortices shed in 3-D simulation of finite-aspect ratio rectangular wing in subsonic flight. Dependence of VC parameter on the flight Mach number and the angle of attack was evaluated. The aerodynamic drag results with application of VC to prevent numerical diffusion are much closer to analytic lifting line theory compared to integration over surface of wing while the viscous profile drag is more accurately evaluated by surface integration. To apply VC to viscous and turbulent flows, it is shown that VC does not affect the physical rate of dissipation of vortices in viscous/turbulent flows at time scales corresponding to convection of vortices from the wing to Trefftz plane of integration. To account for turbulent effects on tip vortices, VC was applied in combination with Spalart-Allmaras, k- ɛ, and six Reynolds stresses models of turbulence. The results are compared to experiments to validate the physical dissipation of tip vortex. This research was supported by The Dayton Area Graduate Studies Institute (DAGSI) and US Air Force Research Laboratory (AFRL) grants in 2009-2013, US Army Research Office (ARO) in 2012-2013 and ASEE/AFRL summer faculty grant.
Conditions for laminar flow in geophysical vortices
NASA Astrophysics Data System (ADS)
Fiedler, Brian H.
1989-01-01
The sufficient condition for inviscid, helical instability at large wavenumbers is applied to solutions for columnar vortices arising from the vortical flow of an end-wall boundary layer. The end-wall vortex arising from the laminar boundary layer under a potential vortex will be unstable at sufficiently high Reynolds number. Hoewever, if the end-wall boundary layer is turbulent, the end-wall vortex can be stable and laminar even at very high Reynolds number; therefore, stable, laminar tornadoes and waterspouts are suggested as theoretical possibilities.
Noise from two-dimensional vortices
NASA Technical Reports Server (NTRS)
Sanders, N. D.; Stockman, N. O.
1972-01-01
The fluctuating flow in an idealized model of a turbulent shear layer composed of many discrete vortices is analyzed. Computer solutions reveal irregular motions which are similar in many respects to observed flows in turbulent three-dimensional layers. The model is further simplified to a pair of equal co-rotating vortices and the noise generation is analyzed in terms of equivalent quadrupole oscillations. Results of the analysis in a uniform medium are consistent with Lighthill's results. New results are obtained for the effects of mean velocity gradients, compressibility, temperature inhomogenities, and gradients of the mean Mach number.
Spatially-partitioned many-body vortices
NASA Astrophysics Data System (ADS)
Klaiman, S.; Alon, O. E.
2016-02-01
A vortex in Bose-Einstein condensates is a localized object which looks much like a tiny tornado storm. It is well described by mean-field theory. In the present work we go beyond the current paradigm and introduce many-body vortices. These are made of spatially- partitioned clouds, carry definite total angular momentum, and are fragmented rather than condensed objects which can only be described beyond mean-field theory. A phase diagram based on a mean-field model assists in predicting the parameters where many-body vortices occur. Implications are briefly discussed.
Linear phase distribution of acoustical vortices
Gao, Lu; Zheng, Haixiang; Ma, Qingyu; Tu, Juan; Zhang, Dong
2014-07-14
Linear phase distribution of phase-coded acoustical vortices was theoretically investigated based on the radiation theory of point source, and then confirmed by experimental measurements. With the proposed criterion of positive phase slope, the possibility of constructing linear circular phase distributions is demonstrated to be determined by source parameters. Improved phase linearity can be achieved at larger source number, lower frequency, smaller vortex radius, and/or longer axial distance. Good agreements are observed between numerical simulations and measurement results for circular phase distributions. The favorable results confirm the feasibility of precise phase control for acoustical vortices and suggest potential applications in particle manipulation.
Electroweak Gauge-Higgs Unification Scenario
Hosotani, Yutaka
2008-11-23
In the gauge-Higgs unification scenario 4D Higgs fields are unified with gauge fields in higher dimensions. The electroweak model is constructed in the Randall-Sundrum warped space. The electroweak symmetry is dynamically broken by the Hosotani mechanism due to the top quark contribution. The Higgs mass is predicted to be around 50 GeV with the vanishing ZZH and WWH couplings so that the LEP2 bound for the Higgs mass is evaded.
Is the Higgs boson composed of neutrinos?
Krog, Jens; Hill, Christopher T.
2015-11-09
We show that conventional Higgs compositeness conditions can be achieved by the running of large Higgs-Yukawa couplings involving right-handed neutrinos that become active at ~10^{13}–10^{14} GeV. Together with a somewhat enhanced quartic coupling arising by a Higgs portal interaction to a dark matter sector, we can obtain a Higgs boson composed of neutrinos. Furthermore, this is a “next-to-minimal” dynamical electroweak symmetry breaking scheme.
THE HIGGS WORKING GROUP: SUMMARY REPORT.
DAWSON, S.; ET AL.
2005-08-01
This working group has investigated Higgs boson searches at the Tevatron and the LHC. Once Higgs bosons are found their properties have to be determined. The prospects of Higgs coupling measurements at the LHC and a high-energy linear e{sup +}e{sup -} collider are discussed in detail within the Standard Model and its minimal supersymmetric extension (MSSM). Recent improvements in the theoretical knowledge of the signal and background processes are presented and taken into account. The residual uncertainties are analyzed in detail. Theoretical progress is discussed in particular for the gluon-fusion processes gg {yields} H(+j), Higgs-bremsstrahlung off bottom quarks and the weak vector-boson-fusion (VBF) processes. Following the list of open questions of the last Les Houches workshop in 2001 several background processes have been calculated at next-to-leading order, resulting in a significant reduction of the theoretical uncertainties. Further improvements have been achieved for the Higgs sectors of the MSSM and NMSSM. This report summarizes our work performed before and after the workshop in Les Houches. Part A describes the theoretical developments for signal and background processes. Part B presents recent progress in Higgs boson searches at the Tevatron collider. Part C addresses the determination of Higgs boson couplings, part D the measurement of tan {beta} and part E Higgs boson searches in the VBF processes at the LHC. Part F summarizes Higgs searches in supersymmetric Higgs decays, part G photonic Higgs decays in Higgs-strahlung processes at the LHC, while part H concentrates on MSSM Higgs bosons in the intense-coupling regime at the LHC. Part I presents progress in charged Higgs studies and part J the Higgs discovery potential in the NMSSM at the LHC. The last part K describes Higgs coupling measurements at a 1 TeV linear e{sup +}e{sup -} collider.
Is the Higgs boson composed of neutrinos?
Krog, Jens; Hill, Christopher T.
2015-11-09
We show that conventional Higgs compositeness conditions can be achieved by the running of large Higgs-Yukawa couplings involving right-handed neutrinos that become active at ~1013–1014 GeV. Together with a somewhat enhanced quartic coupling arising by a Higgs portal interaction to a dark matter sector, we can obtain a Higgs boson composed of neutrinos. Furthermore, this is a “next-to-minimal” dynamical electroweak symmetry breaking scheme.
HiggsSignals: Confronting arbitrary Higgs sectors with measurements at the Tevatron and the LHC
NASA Astrophysics Data System (ADS)
Bechtle, Philip; Heinemeyer, Sven; Stål, Oscar; Stefaniak, Tim; Weiglein, Georg
2014-02-01
HiggsSignals is a Fortran90 computer code that allows to test the compatibility of Higgs sector predictions against Higgs rates and masses measured at the LHC or the Tevatron. Arbitrary models with any number of Higgs bosons can be investigated using a model-independent input scheme based on HiggsBounds. The test is based on the calculation of a measure from the predictions and the measured Higgs rates and masses, with the ability of fully taking into account systematics and correlations for the signal rate predictions, luminosity and Higgs mass predictions. It features two complementary methods for the test. First, the peak-centered method, in which each observable is defined by a Higgs signal rate measured at a specific hypothetical Higgs mass, corresponding to a tentative Higgs signal. Second, the mass-centered method, where the test is evaluated by comparing the signal rate measurement to the theory prediction at the Higgs mass predicted by the model. The program allows for the simultaneous use of both methods, which is useful in testing models with multiple Higgs bosons. The code automatically combines the signal rates of multiple Higgs bosons if their signals cannot be resolved by the experimental analysis. We compare results obtained with HiggsSignals to official ATLAS and CMS results for various examples of Higgs property determinations and find very good agreement. A few examples of HiggsSignals applications are provided, going beyond the scenarios investigated by the LHC collaborations. For models with more than one Higgs boson we recommend to use HiggsSignals and HiggsBounds in parallel to exploit the full constraining power of Higgs search exclusion limits and the measurements of the signal seen at GeV.
New decay modes of heavy Higgs bosons in a two Higgs doublet model with vectorlike leptons
NASA Astrophysics Data System (ADS)
Dermíšek, Radovan; Lunghi, Enrico; Shin, Seodong
2016-05-01
In models with extended Higgs sector and additional matter fields, the decay modes of heavy Higgs bosons can be dominated by cascade decays through the new fermions rendering present search strategies ineffective. We investigate new decay topologies of heavy neutral Higgses in two Higgs doublet model with vectorlike leptons. We also discus constraints from existing searches and discovery prospects. Among the most interesting signatures are monojet, mono Z, mono Higgs, and Z and Higgs bosons produced with a pair of charged leptons.
Higgs friends and counterfeits at hadron colliders
NASA Astrophysics Data System (ADS)
Fox, Patrick J.; Tucker-Smith, David; Weiner, Neal
2011-06-01
We consider the possibility of "Higgs counterfeits" - scalars that can be produced with cross sections comparable to the SM Higgs, and which decay with identical relative observable branching ratios, but which are nonetheless not responsible for electroweak symmetry breaking. We also consider a related scenario involving "Higgs friends," fields similarly produced through gg fusion processes, which would be discovered through diboson channels WW, ZZ, γγ, or even γZ, potentially with larger cross sections times branching ratios than for the Higgs. The discovery of either a Higgs friend or a Higgs counterfeit, rather than directly pointing towards the origin of the weak scale, would indicate the presence of new colored fields necessary for the sizable production cross section (and possibly new colorless but electroweakly charged states as well, in the case of the diboson decays of a Higgs friend). These particles could easily be confused for an ordinary Higgs, perhaps with an additional generation to explain the different cross section, and we emphasize the importance of vector boson fusion as a channel to distinguish a Higgs counterfeit from a true Higgs. Such fields would naturally be expected in scenarios with "effective Z's," where heavy states charged under the SM produce effective charges for SM fields under a new gauge force. We discuss the prospects for discovery of Higgs counterfeits, Higgs friends, and associated charged fields at the LHC.
Physical unitarity for a massive Yang-Mills theory without the Higgs field: A perturbative treatment
NASA Astrophysics Data System (ADS)
Kondo, Kei-Ichi; Suzuki, Kenta; Fukamachi, Hitoshi; Nishino, Shogo; Shinohara, Toru
2013-01-01
In a series of papers, we examine the physical unitarity in a massive Yang-Mills theory without the Higgs field in which the color gauge symmetry is not spontaneously broken and kept intact. For this purpose, we use a new framework proposed in the previous paper Kondo [arXiv:1208.3521] based on a nonperturbative construction of a non-Abelian field describing a massive spin-one vector boson field, which enables us to perform the perturbative and nonperturbative studies on the physical unitarity. In this paper, we present a new perturbative treatment for the physical unitarity after giving the general properties of the massive Yang-Mills theory. Then we reproduce the violation of physical unitarity in a transparent way. This paper is a preliminary work to the subsequent papers in which we present a nonperturbative framework to propose a possible scenario of restoring the physical unitarity in the Curci-Ferrari model.
Radiative mixing of the one Higgs boson and emergent self-interacting dark matter
NASA Astrophysics Data System (ADS)
Ma, Ernest
2016-03-01
In all scalar extensions of the standard model of particle interactions, the one Higgs boson responsible for electroweak symmetry breaking always mixes with other neutral scalars at tree level unless a symmetry prevents it. An unexplored important option is that the mixing may be radiative, and thus guaranteed to be small. Two first such examples are discussed. One is based on the soft breaking of the discrete symmetry Z3. The other starts with the non-Abelian discrete symmetry A4 which is then softly broken to Z3, and results in the emergence of an interesting dark-matter candidate together with a light mediator for the dark matter to have its own long-range interaction.
NASA Astrophysics Data System (ADS)
Lin, Shi-Zeng; Wang, Xueyun; Kamiya, Yoshitomo; Chern, Gia-Wei; Fan, Fei; Fan, David; Casas, Brian; Liu, Yue; Kiryukhin, Valery; Zurek, Wojciech H.; Batista, Cristian D.; Cheong, Sang-Wook
2014-12-01
Lars Onsager and Richard Feynman envisaged that the three-dimensional (3D) superfluid-to-normal λ transition in 4He occurs through the proliferation of vortices. This process should hold for every phase transition in the same universality class. The role of topological defects in symmetry-breaking phase transitions has become a prime topic in cosmology and high-temperature superconductivity, even though direct imaging of these defects is challenging. Here we show that the U(1) continuous symmetry that emerges at the ferroelectric critical point of multiferroic hexagonal manganites leads to a similar proliferation of vortices. Moreover, the disorder field (vortices) is coupled to an emergent U(1) gauge field, which becomes massive by means of the Higgs mechanism when vortices condense (span the whole system) on heating above the ferroelectric transition temperature. Direct imaging of the vortex network in hexagonal manganites offers unique experimental access to this dual description of the ferroelectric transition, while enabling tests of the Kibble-Zurek mechanism.
A factor involved in efficient breakdown of supersonic streamwise vortices
NASA Astrophysics Data System (ADS)
Hiejima, Toshihiko
2015-03-01
Spatially developing processes in supersonic streamwise vortices were numerically simulated at Mach number 5.0. The vortex evolution largely depended on the azimuthal vorticity thickness of the vortices, which governs the negative helicity profile. Large vorticity thickness greatly enhanced the centrifugal instability, with consequent development of perturbations with competing wavenumbers outside the vortex core. During the transition process, supersonic streamwise vortices could generate large-scale spiral structures and a number of hairpin like vortices. Remarkably, the transition caused a dramatic increase in the total fluctuation energy of hypersonic flows, because the negative helicity profile destabilizes the flows due to helicity instability. Unstable growth might also relate to the correlation length between the axial and azimuthal vorticities of the streamwise vortices. The knowledge gained in this study is important for realizing effective fuel-oxidizer mixing in supersonic combustion engines.
Evolution of a barotropic shear layer into elliptical vortices.
Guha, Anirban; Rahmani, Mona; Lawrence, Gregory A
2013-01-01
When a barotropic shear layer becomes unstable, it produces the well-known Kelvin-Helmholtz instability (KHI). The nonlinear manifestation of the KHI is usually in the form of spiral billows. However, a piecewise linear shear layer produces a different type of KHI characterized by elliptical vortices of constant vorticity connected via thin braids. Using direct numerical simulation and contour dynamics, we show that the interaction between two counterpropagating vorticity waves is solely responsible for this KHI formation. We investigate the oscillation of the vorticity wave amplitude, the rotation and nutation of the elliptical vortex, and straining of the braids. Our analysis also provides a possible explanation for the formation and evolution of elliptical vortices appearing in geophysical and astrophysical flows, e.g., meddies, stratospheric polar vortices, Jovian vortices, Neptune's Great Dark Spot, and coherent vortices in the wind belts of Uranus. PMID:23410439
Non-Abelian SU(2) Lattice Gauge Theories in Superconducting Circuits.
Mezzacapo, A; Rico, E; Sabín, C; Egusquiza, I L; Lamata, L; Solano, E
2015-12-11
We propose a digital quantum simulator of non-Abelian pure-gauge models with a superconducting circuit setup. Within the framework of quantum link models, we build a minimal instance of a pure SU(2) gauge theory, using triangular plaquettes involving geometric frustration. This realization is the least demanding, in terms of quantum simulation resources, of a non-Abelian gauge dynamics. We present two superconducting architectures that can host the quantum simulation, estimating the requirements needed to run possible experiments. The proposal establishes a path to the experimental simulation of non-Abelian physics with solid-state quantum platforms. PMID:26705616
Neutrino masses and non-abelian horizontal symmetries
NASA Astrophysics Data System (ADS)
Antonelli, V.; Caravaglios, F.; Ferrari, R.; Picariello, M.
2002-12-01
Recently neutrino experiments have made very significant progresses and our knowledge of neutrino masses and mixing has considerably improved. In a model-independent Monte Carlo approach, we have examined a very large class of textures, in the context of non-abelian horizontal symmetries; we have found that neutrino data select only those charged lepton matrices with left-right asymmetric texture. The large atmospheric mixing angle needs m23≃m33. This result, if combined with similar recent findings for the quark sector in the B oscillations, can be interpreted as a hint for SU(5) unification. In the neutrino sector strict neutrino anarchy is disfavored by data, and at least a factor 2 of suppression in the first row and column of the neutrino Majorana mass matrix is required.
Quantum Hall effects in a non-Abelian honeycomb lattice
NASA Astrophysics Data System (ADS)
Li, Ling; Hao, Ningning; Liu, Guocai; Bai, Zhiming; Li, Zai-Dong; Chen, Shu; Liu, W. M.
2015-12-01
We study the tunable quantum Hall effects in a non-Abelian honeycomb optical lattice which is a multi-Dirac-point system. We find that the quantum Hall effects present different features with the change in relative strengths of several perturbations. Namely, the quantum spin Hall effect can be induced by gauge-field-dressed next-nearest-neighbor hopping, which, together with a Zeeman field, can induce the quantum anomalous Hall effect characterized by different Chern numbers. Furthermore, we find that the edge states of the multi-Dirac-point system represent very different features for different boundary geometries, in contrast with the generic two-Dirac-point system. Our study extends the borders of the field of quantum Hall effects in a honeycomb optical lattice with multivalley degrees of freedom.
Simulation of non-Abelian gauge theories with optical lattices.
Tagliacozzo, L; Celi, A; Orland, P; Mitchell, M W; Lewenstein, M
2013-01-01
Many phenomena occurring in strongly correlated quantum systems still await conclusive explanations. The absence of isolated free quarks in nature is an example. It is attributed to quark confinement, whose origin is not yet understood. The phase diagram for nuclear matter at general temperatures and densities, studied in heavy-ion collisions, is not settled. Finally, we have no definitive theory of high-temperature superconductivity. Though we have theories that could underlie such physics, we lack the tools to determine the experimental consequences of these theories. Quantum simulators may provide such tools. Here we show how to engineer quantum simulators of non-Abelian lattice gauge theories. The systems we consider have several applications: they can be used to mimic quark confinement or to study dimer and valence-bond states (which may be relevant for high-temperature superconductors). PMID:24162080
Simulation of non-Abelian gauge theories with optical lattices
NASA Astrophysics Data System (ADS)
Tagliacozzo, L.; Celi, A.; Orland, P.; Mitchell, M. W.; Lewenstein, M.
2013-10-01
Many phenomena occurring in strongly correlated quantum systems still await conclusive explanations. The absence of isolated free quarks in nature is an example. It is attributed to quark confinement, whose origin is not yet understood. The phase diagram for nuclear matter at general temperatures and densities, studied in heavy-ion collisions, is not settled. Finally, we have no definitive theory of high-temperature superconductivity. Though we have theories that could underlie such physics, we lack the tools to determine the experimental consequences of these theories. Quantum simulators may provide such tools. Here we show how to engineer quantum simulators of non-Abelian lattice gauge theories. The systems we consider have several applications: they can be used to mimic quark confinement or to study dimer and valence-bond states (which may be relevant for high-temperature superconductors).
Abelian Hidden Sectors at a GeV
Morrissey, David E.; Poland, David; Zurek, Kathryn; /Fermilab /Michigan U.
2009-04-16
We discuss mechanisms for naturally generating GeV-scale hidden sectors in the context of weak-scale supersymmetry. Such low mass scales can arise when hidden sectors are more weakly coupled to supersymmetry breaking than the visible sector, as happens when supersymmetry breaking is communicated to the visible sector by gauge interactions under which the hidden sector is uncharged, or if the hidden sector is sequestered from gravity-mediated supersymmetry breaking. We study these mechanisms in detail in the context of gauge and gaugino mediation, and present specific models of Abelian GeV-scale hidden sectors. In particular, we discuss kinetic mixing of a U(1){sub x} gauge force with hypercharge, singlets or bi-fundamentals which couple to both sectors, and additional loop effects. Finally, we investigate the possible relevance of such sectors for dark matter phenomenology, as well as for low- and high-energy collider searches.
Canonical non-Abelian dual transformations in supersymmetric field theories
Curtright, T.; Zachos, C.
1995-07-15
A generating functional {ital F} is found for a canonical non-Abelian dual transformation which maps the supersymmetric chiral O(4) {sigma} model to an equivalent supersymmetric extension of the dual {sigma} model. This {ital F} produces a mapping between the classical phase spaces of the two theories in which the bosonic (coordinate) fields transform nonlocally, the fermions undergo a local tangent space chiral rotation, and all currents (fermionic and bosonic) mix locally. Purely bosonic curvature-free currents of the chiral model become a {ital symphysis} of purely bosonic and fermion bilinear currents of the dual theory. The corresponding transformation functional {ital T} which relates wave functions in the two quantum theories is argued to be {ital exactly} given by {ital T}=exp({ital iF}).
On formulae for the class number of real Abelian fields
NASA Astrophysics Data System (ADS)
Kuz'min, L. V.
1996-08-01
For a given real Abelian field k and a given prime natural number \\ell we obtain an index formula for the order of the group \\operatorname{Cl}(k)_{\\ell,\\varphi}, where \\operatorname{Cl}(k)_{\\ell} is the \\ell-component of the class group of k \\operatorname{Cl}(k)_{\\ell,\\varphi} denotes the \\varphi-component of \\operatorname{Cl}(k)_\\ell corresponding to a {\\mathbf Q}_\\ell-irreducible character \\varphi of the Galois group G(k/{\\mathbf Q}) that is trivial on the Sylow \\ell-subgroup of G(k/{\\mathbf Q}). This result generalizes a conjecture of Gras. The proofs rely on the "main conjecture" of Iwasawa theory.
Non-Abelian gerbes and enhanced Leibniz algebras
NASA Astrophysics Data System (ADS)
Strobl, Thomas
2016-07-01
We present the most general gauge-invariant action functional for coupled 1- and 2-form gauge fields with kinetic terms in generic dimensions, i.e., dropping eventual contributions that can be added in particular space-time dimensions only such as higher Chern-Simons terms. After appropriate field redefinitions it coincides with a truncation of the Samtleben-Szegin-Wimmer action. In the process one sees explicitly how the existence of a gauge-invariant functional enforces that the most general semistrict Lie 2-algebra describing the bundle of a non-Abelian gerbe gets reduced to a very particular structure, which, after the field redefinition, can be identified with the one of an enhanced Leibniz algebra. This is the first step towards a systematic construction of such functionals for higher gauge theories, with kinetic terms for a tower of gauge fields up to some highest form degree p , solved here for p =2 .
Cosmological perturbations: Vorticity, isocurvature and magnetic fields
NASA Astrophysics Data System (ADS)
Christopherson, Adam J.
2014-10-01
In this paper, I review some recent, interlinked, work undertaken using cosmological perturbation theory — a powerful technique for modeling inhomogeneities in the universe. The common theme which underpins these pieces of work is the presence of nonadiabatic pressure, or entropy, perturbations. After a brief introduction covering the standard techniques of describing inhomogeneities in both Newtonian and relativistic cosmology, I discuss the generation of vorticity. As in classical fluid mechanics, vorticity is not present in linearized perturbation theory (unless included as an initial condition). Allowing for entropy perturbations, and working to second order in perturbation theory, I show that vorticity is generated, even in the absence of vector perturbations, by purely scalar perturbations, the source term being quadratic in the gradients of first order energy density and isocurvature, or nonadiabatic pressure perturbations. This generalizes Crocco's theorem to a cosmological setting. I then introduce isocurvature perturbations in different models, focusing on the entropy perturbation in standard, concordance cosmology, and in inflationary models involving two scalar fields. As the final topic, I investigate magnetic fields, which are a potential observational consequence of vorticity in the early universe. I briefly review some recent work on including magnetic fields in perturbation theory in a consistent way. I show, using solely analytical techniques, that magnetic fields can be generated by higher order perturbations, albeit too small to provide the entire primordial seed field, in agreement with some numerical studies. I close this paper with a summary and some potential extensions of this work.
Temporal stability of multiple-cell vortices
NASA Technical Reports Server (NTRS)
Khorrami, M. R.; Grosch, C. E.
1989-01-01
The temporal stability of multiple cell vortices is studied with a staggered Chebyshev spectral collocation technique. It is shown that cell multiplicity in the vortex core has a drastic effect on the stability characteristics. While validating the spectral collocation algorithm, two new viscous modes of instability for Batchelor's (1964) vortex were found. These modes are discussed in detail.
Long Term Changes in the Polar Vortices
NASA Astrophysics Data System (ADS)
Braathen, Geir O.
2016-04-01
As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented. The unusual meteorological conditions of the 2015 south polar vortex and the 2010/11 and 2015/16 north polar vortices will be compared to other recent years.
Experimental Study of Lift-Generated Vortices
NASA Technical Reports Server (NTRS)
Rossow, Vernon J.; Nixon, David (Technical Monitor)
1998-01-01
The flow fields of vortices, whether bouyancy-driven or lift-generated, are fascinating fluid-dynamic phenomena which often possess intense swirl velocities and complex time-dependent behavior. As part of the on-going study of vortex behavior, this paper presents a historical overview of the research conducted on the structure and modification of the vortices generated by the lifting surfaces of subsonic transport aircraft. It is pointed out that the characteristics of lift-generated vortices are related to the aerodynamic shapes that produce them and that various arrangements of surfaces can be used to produce different vortex structures. The primary purpose of the research to be described is to find a way to reduce the hazard potential of lift-generated vortices shed by subsonic transport aircraft in the vicinity of airports during landing and takeoff operations. It is stressed that lift-generated vortex wakes are so complex that progress towards a solution requires application of a combined theoretical and experimental research program because either alone often leads to incorrect conclusions. It is concluded that a satisfactory aerodynamic solution to the wake-vortex problem at airports has not yet been found but a reduction in the impact of the wake-vortex hazard on airport capacity may become available in the foreseeable future through wake-vortex avoidance concepts currently under study. The material to be presented in this overview is drawn from aerospace journals that are available publicly.
Hairpin vortices in turbulent boundary layers
NASA Astrophysics Data System (ADS)
Eitel-Amor, G.; Flores, O.; Schlatter, P.
2014-04-01
The present work addresses the question whether hairpin vortices are a dominant feature of near-wall turbulence and which role they play during transition. First, the parent-offspring mechanism is investigated in temporal simulations of a single hairpin vortex introduced in a mean shear flow corresponding to turbulent channels and boundary layers up to Reτ = 590. Using an eddy viscosity computed from resolved simulations, the effect of a turbulent background is also considered. Tracking the vortical structure downstream, it is found that secondary hairpins are created shortly after initialization. Thereafter, all rotational structures decay, whereas this effect is enforced in the presence of an eddy viscosity. In a second approach, a laminar boundary layer is tripped to transition by insertion of a regular pattern of hairpins by means of defined volumetric forces representing an ejection event. The idea is to create a synthetic turbulent boundary layer dominated by hairpin-like vortices. The flow for Reτ < 250 is analysed with respect to the lifetime of individual hairpin-like vortices. Both the temporal and spatial simulations demonstrate that the regeneration process is rather short-lived and may not sustain once a turbulent background has formed. From the transitional flow simulations, it is conjectured that the forest of hairpins reported in former DNS studies is an outer layer phenomenon not being connected to the onset of near-wall turbulence.
Margaroli, Fabrizio
2014-09-15
We show the latest results from the CDF and D0 collaborations on the study of the Higgs boson, stemming from the analysis of the entire Tevatron Run\\,II dataset. Combining the results of many individual analyses, most of which use the full data set available, an excess with a significance of approximately three standard deviations with respect to the Standard Model hypothesis is observed at a Higgs boson mass of 125\\,GeV/$c^2$. The Tevatron unique environment allows in addition to study for the first time the spin-parity hypothesis of the Higgs boson in events where it decays to quarks. Within the current experimental uncertainties, the newly discovered boson behaves as expected by the SM in the fermionic sector.
The minimal composite Higgs model
NASA Astrophysics Data System (ADS)
Agashe, Kaustubh; Contino, Roberto; Pomarol, Alex
2005-07-01
We study the idea of a composite Higgs in the framework of a five-dimensional AdS theory. We present the minimal model of the Higgs as a pseudo-Goldstone boson in which electroweak symmetry is broken dynamically via top loop effects, all flavour problems are solved, and contributions to electroweak precision observables are below experimental bounds. Since the 5D theory is weakly coupled, we are able to fully determine the Higgs potential and other physical quantities. The lightest resonances are expected to have a mass around 2 TeV and should be discovered at the LHC. The top sector is mostly composite and deviations from Standard Model couplings are expected.
Non-Abelian gauge field theory in scale relativity
NASA Astrophysics Data System (ADS)
Nottale, Laurent; Célérier, Marie-Noëlle; Lehner, Thierry
2006-03-01
Gauge field theory is developed in the framework of scale relativity. In this theory, space-time is described as a nondifferentiable continuum, which implies it is fractal, i.e., explicitly dependent on internal scale variables. Owing to the principle of relativity that has been extended to scales, these scale variables can themselves become functions of the space-time coordinates. Therefore, a coupling is expected between displacements in the fractal space-time and the transformations of these scale variables. In previous works, an Abelian gauge theory (electromagnetism) has been derived as a consequence of this coupling for global dilations and/or contractions. We consider here more general transformations of the scale variables by taking into account separate dilations for each of them, which yield non-Abelian gauge theories. We identify these transformations with the usual gauge transformations. The gauge fields naturally appear as a new geometric contribution to the total variation of the action involving these scale variables, while the gauge charges emerge as the generators of the scale transformation group. A generalized action is identified with the scale-relativistic invariant. The gauge charges are the conservative quantities, conjugates of the scale variables through the action, which find their origin in the symmetries of the "scale-space." We thus found in a geometric way and recover the expression for the covariant derivative of gauge theory. Adding the requirement that under the scale transformations the fermion multiplets and the boson fields transform such that the derived Lagrangian remains invariant, we obtain gauge theories as a consequence of scale symmetries issued from a geometric space-time description.
On Geometrical Interpretation of Non-Abelian Flat Direction Constraints
NASA Astrophysics Data System (ADS)
Cleaver, G. B.; Nanopoulos, D. V.; Perkins, J. T.; Walker, J. W.
In order to produce a low-energy effective field theory from a string model, it is necessary to specify a vacuum state. In order that this vacuum be supersymmetric, it is well known that all field expectation values must be along so-called flat directions, leaving the F- and D-terms of the scalar potential to be zero. The situation becomes particularly interesting when one attempts to realize such directions while assigning vacuum expectation values to fields transforming under non-Abelian representations of the gauge group. Since the expectation value is now shared among multiple components of a field, satisfaction of flatness becomes an inherently geometrical problem in the group space. Furthermore, the possibility emerges that a single seemingly dangerous F-term might experience a self-cancellation among its components. The hope exists that the geometric language can provide an intuitive and immediate recognition of when the D and F conditions are simultaneously compatible, as well as a powerful tool for their comprehensive classification. This is the avenue explored in this paper, and applied to the cases of SU(2) and SO(2N), relevant respectively to previous attempts at reproducing the MSSM and the flipped SU(5) GUT. Geometrical interpretation of non-Abelian flat directions finds application to M-theory through the recent conjecture of equivalence between D-term strings and wrapped D-branes of Type II theory.1 Knowledge of the geometry of the flat direction "landscape" of a D-term string model could yield information about the dual brane model. It is hoped that the techniques encountered will be of benefit in extending the viability of the quasirealistic phenomenologies already developed.
Two-dimensional vortices and accretion disks
NASA Astrophysics Data System (ADS)
Nauta, Michiel Doede
2000-01-01
Observations show that there are disks around certain stars that slowly rain down on the central (compact) object: accretion disks. The rate of depletion of the disk might be slow but is still larger than was expected on theoretical grounds. That is why it has been suggested that the disks are turbulent. Because the disk is thin and rotating this turbulence might be related to two-dimensional (2D) turbulence which is characterized by energy transfers towards small wave numbers and the formation of 2D-vortices. This hypothesis is investigated in this thesis by numerical simulations. After an introduction, the numerical algorithm that was inplemented is discussed together with its relation to an accretion disk. It performs well under the absence of discontinuities. The code is used to study 2D-turbulence under the influence of background rotation with compressibility and a shearing background flow. The first is found to be of little consequence but the shear flow alters 2D-turbulence siginificantly. Only prograde vortices of enough strength are able to withstand the shear flow. The size of the vortices in the cross stream direction is also found to be smaller than the equivalent of the thickness of an accretion disk. These circulstances imply that the assumption of two-dimensionality is questionable so that 2D-vortices might not abound in accretion disks. However, the existence of such vortices is not ruled out and one such a cortex is studied in detail in chapter 4. The internal structure of the vortex is well described by a balance between Coriolis, centrifugal and pressure forces. The vortex is also accompanied by two spiral compressible waves. These are not responsible for the azimuthal drift of the vortex, which results from secondary vortices, but they might be related to the small radial drift that is observed. Radial drift leads to accretion but it is not very efficient. Multiple vortex interactions are the topic of tha last chapter and though interesting the
Hairpin vortices in turbulent boundary layers
NASA Astrophysics Data System (ADS)
Eitel-Amor, G.; Örlü, R.; Schlatter, P.; Flores, O.
2015-02-01
The present work presents a number of parallel and spatially developing simulations of boundary layers to address the question of whether hairpin vortices are a dominant feature of near-wall turbulence, and which role they play during transition. In the first part, the parent-offspring regeneration mechanism is investigated in parallel (temporal) simulations of a single hairpin vortex introduced in a mean shear flow corresponding to either turbulent channels or boundary layers (Reτ ≲ 590). The effect of a turbulent background superimposed on the mean flow is considered by using an eddy viscosity computed from resolved simulations. Tracking the vortical structure downstream, it is found that secondary hairpins are only created shortly after initialization, with all rotational structures decaying for later times. For hairpins in a clean (laminar) environment, the decay is relatively slow, while hairpins in weak turbulent environments (10% of νt) dissipate after a couple of eddy turnover times. In the second part, the role of hairpin vortices in laminar-turbulent transition is studied using simulations of spatial boundary layers tripped by hairpin vortices. These vortices are generated by means of specific volumetric forces representing an ejection event, creating a synthetic turbulent boundary layer initially dominated by hairpin-like vortices. These hairpins are advected towards the wake region of the boundary layer, while a sinusoidal instability of the streaks near the wall results in rapid development of a turbulent boundary layer. For Reθ > 400, the boundary layer is fully developed, with no evidence of hairpin vortices reaching into the wall region. The results from both the parallel and spatial simulations strongly suggest that the regeneration process is rather short-lived and may not sustain once a turbulent background is developed. From the transitional flow simulations, it is conjectured that the forest of hairpins reported in former direct numerical
Higgs triplets and limits from precision measurements
Chen, Mu-Chun; Dawson, Sally; Krupovnickas, Tadas; /Brookhaven
2006-04-01
In this letter, they present the results on a global fit to precision electroweak data in a Higgs triplet model. In models with a triplet Higgs boson, a consistent renormalization scheme differs from that of the Standard Model and the global fit shows that a light Higgs boson with mass of 100-200 GeV is preferred. Triplet Higgs bosons arise in many extensions of the Standard Model, including the left-right model and the Little Higgs models. The result demonstrates the importance of the scalar loops when there is a large mass splitting between the heavy scalars. It also indicates the significance of the global fit.
Controlled Manipulation of Individual Vortices in a Superconductor
Straver, E.W.J.
2010-04-05
We report controlled local manipulation of single vortices by low temperature magnetic force microscope (MFM) in a thin film of superconducting Nb. We are able to position the vortices in arbitrary configurations and to measure the distribution of local depinning forces. This technique opens up new possibilities for the characterization and use of vortices in superconductors.
An eddy closure for potential vorticity
Ringler, Todd D
2009-01-01
The Gent-McWilliams (GM) parameterization is extended to include a direct influence in the momentum equation. The extension is carried out in two stages; an analysis of the inviscid system is followed by an analysis of the viscous system. In the inviscid analysis the momentum equation is modified such that potential vorticity is conserved along particle trajectories following a transport velocity that includes the Bolus velocity in a manner exactly analogous to the continuity and tracer equations. In addition (and in contrast to traditional GM closures), the new formulation of the inviscid momentum equation results in a conservative exchange between potential and kinetic forms of energy. The inviscid form of the eddy closure conserves total energy to within an error proportional to the time derivative of the Bolus velocity. The hypothesis that the viscous term in the momentum equation should give rise to potential vorticity being diffused along isopycnals in a manner analogous to other tracers is examined in detail. While the form of the momentum closure that follows from a strict adherence to this hypothesis is not immediately interpretable within the constructs of traditional momentum closures, three approximations to this hypothesis results in a form of dissipation that is consistent with traditional Laplacian diffusion. The first two approximations are that relative vorticity, not potential vorticity, is diffused along isopyncals and that the flow is in approximate geostrophic balance. An additional approximation to the Jacobian term is required when the dissipation coefficient varies in space. More importantly, the critique of this hypothesis results in the conclusion that the viscosity parameter in the momentum equation should be identical to the tradition GM closure parameter {Kappa}. Overall, we deem the viscous form of the eddy closure for potential vorticity as a viable closure for use in ocean circulation models.
Bilinear relative equilibria of identical point vortices
NASA Astrophysics Data System (ADS)
Aref, Hassan; Beelen, Peter; Brøns, Morten
2011-11-01
A new class of bilinear relative equilibria of identical point vortices in which the vortices are constrained to be on two perpendicular lines, taken to be the x- and y-axes of a cartesian coordinate system, is introduced and studied. In general we have m vortices on the y-axis and n on the x- axis. We define generating polynomials q (z) and p (z) , respectively, for each set of vortices. A second order, linear ODE for p (z) given q (z) is derived. Several results relating the general solution of the ODE to relative equilibrium configurations are established. Our strongest result, obtained using Sturm's comparison theorem, is that if p (z) satisfies the ODE for a given q (z) with its imaginary zeros symmetric relative to the x-axis, then it must have at least n - m + 2 simple, real zeros. For m = 2 this provides a complete characterization of all zeros, and we study this case in some detail. In particular, we show that given q (z) =z2 +η2 , where η is real, there is a unique p (z) of degree n, and a unique value of η2 =An , such that the zeros of q (z) and p (z) form a relative equilibrium of n + 2 point vortices. We show that An ~2/3 n +1/2 , as n --> ∞ , where the coefficient of n is determined analytically, the next order term numerically. Supported in part by the Danish National Research Foundation through a Niels Bohr visiting professorship.
NASA Astrophysics Data System (ADS)
Cai, Haiying; Cheng, Hsin-Chia; Terning, John
2009-05-01
We consider an extra dimensional model where the quadratically divergent top loop contribution to the Higgs mass is cancelled by an uncolored heavy ``top quirk" charged under a different SU(3) gauge group. The cancellation is enforced by bulk gauge symmetries. Thus we have an unusual type of little Higgs model which has some quirky signatures. The top partner in this model could be identified at the Large Hadron Collider due to macroscopic strings that connect quirk and anti-quirks. The model can undergo radiative electroweak symmetry breaking and is consistent with precision electroweak measurements.
Low, I.; Schwaller, P.; Shaughnessy, G.; Wagner, C. E. M.
2012-01-01
Current limits from the Large Hadron Collider exclude a standard model-like Higgs mass above 150 GeV, by placing an upper bound on the Higgs production rate. We emphasize that, alternatively, the limit could be interpreted as a lower bound on the total decay width of the Higgs boson. If the invisible decay width of the Higgs is of the same order as the visible decay width, a heavy Higgs boson could be consistent with null results from current searches. We propose a method to infer the invisible decay of the Higgs by using the width of the measured h {yields} ZZ {yields} 4 {ell} line shape, and study the effect on the width extraction due to a reduced signal strength. Assuming the invisible decay product is the dark matter, we show that minimal models are tightly constrained by limits from Higgs searches at the LHC and direct detection experiments of dark matter, unless the relic density constraint is relaxed.
Beyond parafermions: Defects and zero-modes in non-Abelian phases
NASA Astrophysics Data System (ADS)
Lindner, Netanel; Berg, Erez; Stern, Ady
Non-Abelian topological phases of matter can be utilized to encode and manipulate quantum information in a non-local manner, such that it is protected from imperfections in the implemented protocols and from interactions with the environment. The condition that the non-Abelian statistics of the anyons supports a computationally universal set of gates sets a very stringent requirement which is not met by many topological phases. We consider the possibility to enrich the possible topological operations supported by a non-Abelian topological phase by introducing defects into the system. We show that such defects bind zero modes which form a unique algebra that goes beyond the algebra of parafermions which describes defects in Abelian phases. For the case of a bi-layer containing Ising anyons, we show that by coupling zero modes one can obtain a set of topological operations that implements a universal set of gates.
Field theory aspects of non-Abelian T-duality and {N} =2 linear quivers
NASA Astrophysics Data System (ADS)
Lozano, Yolanda; Núñez, Carlos
2016-05-01
In this paper we propose a linear quiver with gauge groups of increasing rank as field theory dual to the AdS 5 background constructed by Sfetsos and Thompson through non-Abelian T-duality. The formalism to study 4d {N} = 2 SUSY CFTs developed by Gaiotto and Maldacena is essential for our proposal. We point out an interesting relation between (Hopf) Abelian and non-Abelian T-dual backgrounds that allows to see both backgrounds as different limits of a solution constructed by Maldacena and Núñez. This suggests different completions of the long quiver describing the CFT dual to the nonAbelian T-dual background that match different observables.
Collective states of non-Abelian quasiparticles in a magnetic field
NASA Astrophysics Data System (ADS)
Levin, Michael; Halperin, Bertrand I.
2009-05-01
Motivated by the physics of the Moore-Read ν=1/2 state away from half filling, we investigate collective states of non-Abelian e/4 quasiparticles in a magnetic field. We consider two types of collective states: incompressible liquids and Wigner crystals. In the incompressible liquid case, we construct a natural series of states which can be thought of as a non-Abelian generalization of the Laughlin states. These states are associated with a series of hierarchical states derived from the Moore-Read state—the simplest of which occur at filling fraction 8/17 and 7/13. Interestingly, we find that the hierarchical states are Abelian even though their parent state is non-Abelian. In the Wigner crystal case, we construct two candidate states. We find that they, too, are Abelian—in agreement with previous analysis.
Measuring vortical flows in the solar interior
NASA Astrophysics Data System (ADS)
Langfellner, Jan
2015-09-01
This thesis focuses on observations of the effects of rotation on solar convection at the length scales of supergranulation and larger (>30 Mm). Rotation drives vortical flows through the Coriolis force and causes anisotropic velocity correlations that are believed to influence the large-scale solar dynamics. We obtain horizontal flows using photospheric Doppler velocity and continuum intensity images from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) spacecraft via the techniques of time-distance helioseismology (TD) and local correlation tracking (LCT) of granules. In time-distance helioseismology, the local vertical vorticity can be measured by taking the difference between wave travel times measured in the anti-clockwise and clockwise directions along a closed contour. The agreement between the TD and LCT methods is excellent up to Â±60Â° latitude, provided that a center-to-limb correction is applied. Averaging over longitude, one finds that there is a small but significant correlation between the horizontal divergence and the vertical vorticity component of supergranular flows away from the solar equator. By comparison to a noise model, we find that the TD technique can be used to probe the vertical vorticity of flows on spatial scales larger than about 15 Mm, thus including supergranules and also giant cells. We also find that the vertical vorticity signal is much easier to measure using SDO/HMI observations than previous observations. The impact of the Sun's rotation on supergranulation is studied in detail by making spatial maps of the vertical vorticity of the flows associated with the average supergranule. The average supergranule is constructed by co-aligning thousands of individual supergranules in a given latitude band. For the first time, we are able to spatially resolve vorticity associated with inflows and outflow regions. In the northern hemisphere, outflows are on average associated with a clockwise
Higgs masses and stability in the standard and the two Higgs doublet models
Juarez W, S. R.; Morales C, D.; Kielanowski, P.
2010-07-29
Within the framework of the standard model (SM) of elementary particles and the two Higgs doublet extension to this model (2DHM), we obtained analytical and numerical solutions for the gauge couplings, the vacuum expectation values (VEV) of the Higgs fields, the quark Yukawa couplings and quark masses, the quartic Higgs couplings, and the running Higgs masses, considering the renormalization group equations. The bounds on the SM Higgs running mass have been fixed, and the region of validity of the SM was determined through it, at the one and two loop approximations, using the triviality and stability conditions for the Higgs quartic coupling {lambda}{sub H}.
Double Higgs production in the Two Higgs Doublet Model at the linear collider
Arhrib, Abdesslam; Benbrik, Rachid; Chiang, C.-W.
2008-04-21
We study double Higgs-strahlung production at the future Linear Collider in the framework of the Two Higgs Doublet Models through the following channels: e{sup +}e{sup -}{yields}{phi}{sub i}{phi}{sub j}Z, {phi}{sub i} = h deg., H deg., A deg. All these processes are sensitive to triple Higgs couplings. Hence observations of them provide information on the triple Higgs couplings that help reconstructing the scalar potential. We discuss also the double Higgs-strahlung e{sup +}e{sup -}{yields}h deg. h deg. Z in the decoupling limit where h deg. mimics the SM Higgs boson.
NASA Astrophysics Data System (ADS)
Mross, David F.; Essin, Andrew; Alicea, Jason; Stern, Ady
2016-01-01
We show that boundaries of 3D weak topological insulators can become gapped by strong interactions while preserving all symmetries, leading to Abelian surface topological order. The anomalous nature of weak topological insulator surfaces manifests itself in a nontrivial action of symmetries on the quasiparticles; most strikingly, translations change the anyon types in a manner impossible in strictly 2D systems with the same symmetry. As a further consequence, screw dislocations form non-Abelian defects that trap Z4 parafermion zero modes.
Magnetic monopoles and Abelian gauge fixing in SU(4) gauge group
NASA Astrophysics Data System (ADS)
Rafibakhsh, Shahnoosh; Eshraghi, Mojtaba; Kahnemuii, Mohammad Javad
2016-01-01
Abelian gauge fixing procedure is used to create the SU (4) magnetic monopoles in the vicinity of the points where the gluon field becomes singular. The matrix of the scalar field is considered as almost diagonal in the SU (2) and SU (3) subspaces. The gauge transformation which diagonalizes the hedgehog filed, transforms the gluon field into two regular and singular parts. The abelian magnetic monopoles which appear in the latter part obey the quantization condition.
Recovering the vorticity of a light beam after scattering
Salla, Gangi Reddy Perumangattu, Chithrabhanu; Anwar, Ali; Prabhakar, Shashi; Singh, Ravindra P.
2015-07-13
We generate optical vortices and scatter them through a rough surface. However, the scattered light passing through a lens shows the same vorticity when probed at the Fourier plane. The vorticity is measured using a nonseparable state of polarization and orbital angular momentum of light as it cannot be confirmed by the standard interferometric technique. The observed vorticity is found to be independent of the amount of scattered light collected. Therefore, vortices can be used as information carriers even in the presence of scattering media. The experimental results are well supported by the theoretical results.
Recovering the vorticity of a light beam after scattering
NASA Astrophysics Data System (ADS)
Salla, Gangi Reddy; Perumangattu, Chithrabhanu; Prabhakar, Shashi; Anwar, Ali; Singh, Ravindra P.
2015-07-01
We generate optical vortices and scatter them through a rough surface. However, the scattered light passing through a lens shows the same vorticity when probed at the Fourier plane. The vorticity is measured using a nonseparable state of polarization and orbital angular momentum of light as it cannot be confirmed by the standard interferometric technique. The observed vorticity is found to be independent of the amount of scattered light collected. Therefore, vortices can be used as information carriers even in the presence of scattering media. The experimental results are well supported by the theoretical results.
The Higgs boson and cosmology.
Shaposhnikov, Mikhail
2015-01-13
I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe; producing the quantum fluctuations that seed structure formation; triggering the radiation-dominated era of the hot Big Bang; and contributing to the processes of baryogenesis and dark matter production. PMID:26949807
Englert, Christoph; Roy, Tuhin S.; Spannowsky, Michael
2011-10-01
Understanding and identifying ditau jets--jets consisting of pairs of tau particles--can be of crucial importance and may even turn out to be a necessity if the Higgs boson decays dominantly to new light scalars which, on the other hand, decay to tau pairs. As often seen in various models beyond the standard model such as in the next-to-minimal supersymmetric standard model, Higgs portals, etc., the lightness of these new states ensures their large transverse momenta and, as a consequence, the collinearity of their decay products. We show that the nonstandard signatures of these objects, which can easily be missed by standard analysis techniques, can be superbly exploited in an analysis based on subjet observables. When combined with additional selection strategies, this analysis can even facilitate an early discovery of the Higgs boson. To be specific, a light Higgs can be found with S/{radical}(B) > or approx. 5 from L{approx_equal}12 fb{sup -1} of data. We combine all these observables into a single discriminating likelihood that can be employed toward the construction of a realistic and standalone ditau tagger.
Shaposhnikov, Mikhail
2015-01-01
I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe; producing the quantum fluctuations that seed structure formation; triggering the radiation-dominated era of the hot Big Bang; and contributing to the processes of baryogenesis and dark matter production.
NASA Astrophysics Data System (ADS)
García García, Isabel; Lasenby, Robert; March-Russell, John
2015-09-01
Dark matter (DM) without a matter asymmetry is studied in the context of twin Higgs (TH) theories in which the LHC naturalness problem is addressed. These possess a twin sector related to the Standard Model (SM) by a (broken) Z2 symmetry, and interacting with the SM via a specific Higgs portal. We focus on the minimal realization of the TH mechanism, the fraternal twin Higgs, with only a single generation of twin quarks and leptons, and the S U (3 )'×S U (2 )' gauge group. We show that a variety of natural twin-WIMP DM candidates are present (directly linked to the weak scale by naturalness), the simplest and most attractive being the τ' lepton with a mass mτ'>mHiggs/2 , although spin-1 W'± DM and multicomponent DM are also possible (twin baryons are strongly disfavored by tuning). We consider in detail the dynamics of the possibly (meta)stable glueballs in the twin sector, the nature of the twin QCD phase transition, and possible new contributions to the number of relativistic degrees of freedom, Δ Neff . Direct detection signals are below current bounds but accessible in near-future experiments. Indirect detection phenomenology is rich and requires detailed studies of twin hadronization and fragmentation to twin glueballs and quarkonia and their subsequent decay to SM, and possible light twin sector states.
Lee, Hye Sung; Sher, Marc
2013-06-01
We perform a detailed study of a specific Two Higgs Doublet Model (2HDM) with a U(1) gauge symmetry, instead of a typical Z{sub 2} discrete symmetry, containing a very light gauge boson Z' (GeV scale or below). The Standard Model (SM) fermions do not carry U(1) charges, but induced couplings to the Z' (called the dark Z) are generated through mixing with the SM neutral gauge bosons. Such a light Z' could explain some astrophysical anomalies as well as the muon g-2 deviation, and has been the subject of great experimental interest. We consider the scenario in which the 125 GeV SM-like Higgs (H) is the heavier scalar state, and focus on the lighter neutral state (h) as well as charged Higgs. We analyze the constraints on the model from various experiments and predict novel channels to search for these Higgs scalars at the LHC. In particular, experiments looking for lepton-jets are among potentially important searches.
Intensity of vortices: from soap bubbles to hurricanes
Meuel, T.; Xiong, Y. L.; Fischer, P.; Bruneau, C. H.; Bessafi, M.; Kellay, H.
2013-01-01
By using a half soap bubble heated from below, we obtain large isolated single vortices whose properties as well as their intensity are measured under different conditions. By studying the effects of rotation of the bubble on the vortex properties, we found that rotation favors vortices near the pole. Rotation also inhibits long life time vortices. The velocity and vorticity profiles of the vortices obtained are well described by a Gaussian vortex. Besides, the intensity of these vortices can be followed over long time spans revealing periods of intensification accompanied by trochoidal motion of the vortex center, features which are reminiscent of the behavior of tropical cyclones. An analysis of this intensification period suggests a simple relation valid for both the vortices observed here and for tropical cyclones. PMID:24336410
Development and Interaction of Artificially Generated Hairpin Vortices
NASA Astrophysics Data System (ADS)
Sabatino, Daniel; McKenna, Christopher
2012-11-01
The development and interaction of hairpin vortices are examined and categorized to better understand their role in fully turbulent boundary layers. Hairpin vortices are generated within an otherwise laminar boundary layer using a free surface water channel. Direct injection is the primary generation method and the behavior of the vortices is first examined using flow visualization. Hydrogen bubble wire is combined with dye injection to help clarify the role of the vorticity in the fluid immediately surrounding the hairpin vortex. PIV data is also used to classify the development and maturity of the vortices for a range of free stream and injection conditions. The interactions of two hairpin vortices of varying maturity are characterized to investigate the potential mechanisms for the formation of hairpin packets beyond autogeneration. Finally, the behavior of hairpin vortices generated with a new technique that uses a transient hemispherical protrusion is also examined. Supported by the National Science Foundation under Grant CBET-1040236.
Instability of isolated hollow vortices with zero circulation
NASA Astrophysics Data System (ADS)
Hiejima, Toshihiko
2016-04-01
Inviscid linear stability analysis and numerical simulations are used to investigate how temporal disturbances evolve in double-annular hollow vortices with an opposite-signed vorticity (the total circulation is zero). Two extrema exist in the vorticity profile and constitute a factor of instability. The dispersion relation is expressed as a simple cubic equation. The results show that the instabilities of vortices are strongly enhanced by the hollow effect of the annular vorticity. In addition, the growth rate of the dominant modes significantly increases with decreasing negative-vorticity thickness. During the initial stage, the dominant unstable modes obtained from simulations are consistent with those obtained from the linear analysis. In nonlinear developments, the flow field stretches out in one direction depending on the motion of the plural vortex pair formed by rolling up the positive and negative vorticities. Once such structures in the vortex are generated, the vortex immediately breaks down and does not become metastable.
Intensity of vortices: from soap bubbles to hurricanes
NASA Astrophysics Data System (ADS)
Meuel, T.; Xiong, Y. L.; Fischer, P.; Bruneau, C. H.; Bessafi, M.; Kellay, H.
2013-12-01
By using a half soap bubble heated from below, we obtain large isolated single vortices whose properties as well as their intensity are measured under different conditions. By studying the effects of rotation of the bubble on the vortex properties, we found that rotation favors vortices near the pole. Rotation also inhibits long life time vortices. The velocity and vorticity profiles of the vortices obtained are well described by a Gaussian vortex. Besides, the intensity of these vortices can be followed over long time spans revealing periods of intensification accompanied by trochoidal motion of the vortex center, features which are reminiscent of the behavior of tropical cyclones. An analysis of this intensification period suggests a simple relation valid for both the vortices observed here and for tropical cyclones.
Higgs in bosonic channels (CMS)
NASA Astrophysics Data System (ADS)
Gori, Valentina
2015-05-01
The main Higgs boson decays into bosonic channels will be considered, presenting and discussing results from the latest reprocessing of data collected by the CMS experiment at the LHC, using the full dataset recorded at centre-of-mass energies of 7 and 8 TeV. For this purpose, results from the final Run-I papers for the H → ZZ → 4ℓ, H → γγ and H → WW analyses are presented, focusing on the Higgs boson properties, like the mass, the signal strenght, the couplings to fermions and vector bosons, the spin and parity properties. Furthermore, the Higgs boson width measurement exploiting the on-shell versus the off-shell cross section (in the H → ZZ → 4ℓ and H → ZZ → 2ℓ2ν decay channels) will be shown. All the investigated properties result to be fully consistent with the SM predictions: the signal strength and the signal strength modifiers are consistent with unity in all the bosonic channels considered; the hypothesis of a scalar particle is strongly favored, against the pseudoscalar or the vector/pseudovector or the spin-2 boson hypotheses (all excluded at 99% CL or higher in the H → ZZ → 4ℓ channel). The Higgs boson mass measurement from the combination of H → ZZ → 4ℓ and H → γγ channels gives a value mH = 125.03+0.26-0.27 (stat.) +0.13-0.15 (syst.). An upper limit ΓH < 22 MeV can be put on the Higgs boson width thanks to the new indirect method.
Emergent vortices in populations of colloidal rollers
Bricard, Antoine; Caussin, Jean-Baptiste; Das, Debasish; Savoie, Charles; Chikkadi, Vijayakumar; Shitara, Kyohei; Chepizhko, Oleksandr; Peruani, Fernando; Saintillan, David; Bartolo, Denis
2015-01-01
Coherent vortical motion has been reported in a wide variety of populations including living organisms (bacteria, fishes, human crowds) and synthetic active matter (shaken grains, mixtures of biopolymers), yet a unified description of the formation and structure of this pattern remains lacking. Here we report the self-organization of motile colloids into a macroscopic steadily rotating vortex. Combining physical experiments and numerical simulations, we elucidate this collective behaviour. We demonstrate that the emergent-vortex structure lives on the verge of a phase separation, and single out the very constituents responsible for this state of polar active matter. Building on this observation, we establish a continuum theory and lay out a strong foundation for the description of vortical collective motion in a broad class of motile populations constrained by geometrical boundaries. PMID:26088835
Trailing vortices from low speed flyers
NASA Astrophysics Data System (ADS)
Waldman, Rye; Kudo, Jun; Breuer, Kenneth
2009-11-01
The structure and strength of the vortex wake behind a airplane or animal flying with a fixed or flapping wing contains valuable information about the aerodynamic load history. However, the amount of vorticity measured in the trailing vortex is not always in agreement with the known lift generated, and the behavior of these vortices at relatively low Reynolds numbers is also not well-understood. We present the results from a series of wind tunnel PIV experiments conducted behind a low-aspect ratio rectangular wing at a chord-Reynolds numbers of 30,000. In addition to wake PIV measurements measured in the cross-stream (Trefftz) plane, we measure the lift and drag directly using a six-axis force-torque transducer. We discuss how vortex size, shape, strength and position vary in time and downstream location, as well as the challenges associated with the use of PIV wake measurements to accurate determine aerodynamic forces.
Emergent vortices in populations of colloidal rollers.
Bricard, Antoine; Caussin, Jean-Baptiste; Das, Debasish; Savoie, Charles; Chikkadi, Vijayakumar; Shitara, Kyohei; Chepizhko, Oleksandr; Peruani, Fernando; Saintillan, David; Bartolo, Denis
2015-01-01
Coherent vortical motion has been reported in a wide variety of populations including living organisms (bacteria, fishes, human crowds) and synthetic active matter (shaken grains, mixtures of biopolymers), yet a unified description of the formation and structure of this pattern remains lacking. Here we report the self-organization of motile colloids into a macroscopic steadily rotating vortex. Combining physical experiments and numerical simulations, we elucidate this collective behaviour. We demonstrate that the emergent-vortex structure lives on the verge of a phase separation, and single out the very constituents responsible for this state of polar active matter. Building on this observation, we establish a continuum theory and lay out a strong foundation for the description of vortical collective motion in a broad class of motile populations constrained by geometrical boundaries. PMID:26088835
Shear-Layer Effects on Trailing Vortices
NASA Technical Reports Server (NTRS)
Zheng, Z. C.; Baek, K.
1998-01-01
Crosswind shear can influence the trailing vortex trajectories significantly, according to both field measurement and numerical simulations. Point vortex models are used in this paper to study the fluid dynamic mechanism in the interactions between trailing vortex pair and shear layers. It has been shown that the shear-layer deformation causes the vortex descent history difference in the two vortices of the vortex pair. When a shear layer is below the vortex pair with the same sign as the left vortex, the right vortex descends less than the left vortex. When the same shear layer is above the vortex pair, the right vortex descends more. The descent altitudes of the two vortices are the same when they go through a constant, non-deformed shear layer. Those trends are in agreement with Navier-Stokes simulations.
Helical vortices: viscous dynamics and instability
NASA Astrophysics Data System (ADS)
Rossi, Maurice; Selcuk, Can; Delbende, Ivan; Ijlra-Upmc Team; Limsi-Cnrs Team
2014-11-01
Understanding the dynamical properties of helical vortices is of great importance for numerous applications such as wind turbines, helicopter rotors, ship propellers. Locally these flows often display a helical symmetry: fields are invariant through combined axial translation of distance Δz and rotation of angle θ = Δz / L around the same z-axis, where 2 πL denotes the helix pitch. A DNS code with built-in helical symmetry has been developed in order to compute viscous quasi-steady basic states with one or multiple vortices. These states will be characterized (core structure, ellipticity, ...) as a function of the pitch, without or with an axial flow component. The instability modes growing in the above base flows and their growth rates are investigated by a linearized version of the DNS code coupled to an Arnoldi procedure. This analysis is complemented by a helical thin-cored vortex filaments model. ANR HELIX.
Motion of vortices outside a cylinder
NASA Astrophysics Data System (ADS)
Tulu, Serdar; Yilmaz, Oguz
2010-12-01
The problem of motion of the vortices around an oscillating cylinder in the presence of a uniform flow is considered. The Hamiltonian for vortex motion for the case with no uniform flow and stationary cylinder is constructed, reduced, and constant Hamiltonian (energy) curves are plotted when the system is shown to be integrable according to Liouville. By adding uniform flow to the system and by allowing the cylinder to vibrate, we model the natural vibration of the cylinder in the flow field, which has applications in ocean engineering involving tethers or pipelines in a flow field. We conclude that in the chaotic case forces on the cylinder may be considerably larger than those on the integrable case depending on the initial positions of vortices and that complex phenomena such as chaotic capture and escape occur when the initial positions lie in a certain region.
Exact Solitary Water Waves with Vorticity
NASA Astrophysics Data System (ADS)
Hur, Vera Mikyoung
2008-05-01
The solitary water wave problem is to find steady free surface waves which approach a constant level of depth in the far field. The main result is the existence of a family of exact solitary waves of small amplitude for an arbitrary vorticity. Each solution has a supercritical parameter value and decays exponentially at infinity. The proof is based on a generalized implicit function theorem of the Nash-Moser type. The first approximation to the surface profile is given by the “KdV” equation. With a supercritical value of the surface tension coefficient, a family of small amplitude solitary waves of depression with subcritical parameter values is constructed for an arbitrary vorticity.
Anomalous energetics and dynamics of moving vortices
NASA Astrophysics Data System (ADS)
Radzihovsky, Leo
Motivated by the general problem of moving topological defects in an otherwise ordered state and specifically, by the anomalous dynamics observed in vortex-antivortex annihilation and coarsening experiments in freely-suspended smectic-C films, I study the deformation, energetics and dynamics of moving vortices in an overdamped xy-model and show that their properties are significantly and qualitatively modified by the motion. Supported by NSF through DMR-1001240, MRSEC DMR-0820579, and by Simons Investigator award from Simons Foundation.
Vortices in rotating superfluid 3He.
Lounasmaa, O V; Thuneberg, E
1999-07-01
In this review we first present an introduction to 3He and to the ROTA collaboration under which most of the knowledge on vortices in superfluid 3He has been obtained. In the physics part, we start from the exceptional properties of helium at millikelvin temperatures. The dilemma of rotating superfluids is presented. In 4He and in 3He-B the problem is solved by nucleating an array of singular vortex lines. Their experimental detection in 3He by NMR is described next. The vortex cores in 3He-B have two different structures, both of which have spontaneously broken symmetry. A spin-mass vortex has been identified as well. This object is characterized by a flow of spins around the vortex line, in addition to the usual mass current. A great variety of vortices exist in the A phase of 3He; they are either singular or continuous, and their structure can be a line or a sheet or fill the whole liquid. Altogether seven different types of vortices have been detected in 3He by NMR. We also describe briefly other experimental methods that have been used by ROTA scientists in studying vortices in 3He and some important results thus obtained. Finally, we discuss the possible applications of experiments and theory of 3He to particle physics and cosmology. In particular, we report on experiments where superfluid 3He-B was heated locally by absorption of single neutrons. The resulting events can be used to test theoretical models of the Big Bang at the beginning of our universe. PMID:10393895
Admissible upstream conditions for slender compressible vortices
NASA Technical Reports Server (NTRS)
Liu, C. H.; Krause, E.; Menne, S.
1986-01-01
The influence of the compressibility on the flow in slender vortices is being studied. The dependence of the breakdown of the slender-vortex approximation on the upstream conditions is demonstrated for various Reynolds numbers and Mach numbers. Compatibility conditions, which have to be satisfied if the vortex is to remain slender, are discussed in detail. The general discussions are supplemented by several sample calculations.
Vortices in rotating superfluid 3He
Lounasmaa, Olli V.; Thuneberg, Erkki
1999-01-01
In this review we first present an introduction to 3He and to the ROTA collaboration under which most of the knowledge on vortices in superfluid 3He has been obtained. In the physics part, we start from the exceptional properties of helium at millikelvin temperatures. The dilemma of rotating superfluids is presented. In 4He and in 3He-B the problem is solved by nucleating an array of singular vortex lines. Their experimental detection in 3He by NMR is described next. The vortex cores in 3He-B have two different structures, both of which have spontaneously broken symmetry. A spin-mass vortex has been identified as well. This object is characterized by a flow of spins around the vortex line, in addition to the usual mass current. A great variety of vortices exist in the A phase of 3He; they are either singular or continuous, and their structure can be a line or a sheet or fill the whole liquid. Altogether seven different types of vortices have been detected in 3He by NMR. We also describe briefly other experimental methods that have been used by ROTA scientists in studying vortices in 3He and some important results thus obtained. Finally, we discuss the possible applications of experiments and theory of 3He to particle physics and cosmology. In particular, we report on experiments where superfluid 3He-B was heated locally by absorption of single neutrons. The resulting events can be used to test theoretical models of the Big Bang at the beginning of our universe. PMID:10393895
Anomalous Energetics and Dynamics of Moving Vortices
NASA Astrophysics Data System (ADS)
Radzihovsky, Leo
2015-12-01
Motivated by the general problem of moving topological defects in an otherwise ordered state and specifically, by the anomalous dynamics observed in vortex-antivortex annihilation and coarsening experiments in freely suspended smectic-C films, I study the deformation, energetics, and dynamics of moving vortices in an overdamped X Y model and show that their properties are significantly and qualitatively modified by the motion.
Anomalous Energetics and Dynamics of Moving Vortices.
Radzihovsky, Leo
2015-12-11
Motivated by the general problem of moving topological defects in an otherwise ordered state and specifically, by the anomalous dynamics observed in vortex-antivortex annihilation and coarsening experiments in freely suspended smectic-C films, I study the deformation, energetics, and dynamics of moving vortices in an overdamped XY model and show that their properties are significantly and qualitatively modified by the motion. PMID:26705656
Potential vorticity formulation of compressible magnetohydrodynamics.
Arter, Wayne
2013-01-01
Compressible ideal magnetohydrodynamics is formulated in terms of the time evolution of potential vorticity and magnetic flux per unit mass using a compact Lie bracket notation. It is demonstrated that this simplifies analytic solution in at least one very important situation relevant to magnetic fusion experiments. Potentially important implications for analytic and numerical modelling of both laboratory and astrophysical plasmas are also discussed. PMID:23383802
Chiral Self-Gravitating Cosmic Vortices
Rybakov, Yu.P.
2005-06-01
In the framework of general relativity, an exact axisymmetric (vortex) solution of the equations of motion is obtained for the SU(2) symmetric sigma model. This solution is characterized by the topological charge (winding number) and angular deficit. In the linearized approximation, the Lyapunov stability of vortices is proved and the deflection angle of a light ray in the gravitational field of the vortex (gravitational lens effect) is calculated.
Surface Signature of Subsurface-Intensified Vortices
NASA Astrophysics Data System (ADS)
Ciani, D.; Carton, X. J.; Chapron, B.; Bashmachnikov, I.
2014-12-01
The ocean at mesoscale (20-200 km) and submesoscale (0.5-20km) is highly populated by vortices. These recirculating structures are more energetic than the mean flow, they trap water masses from their origin areas and advect them across the ocean, with consequent impact on the 3D distribution of heat and tracers. Mesoscale and submesoscale structures characterize the ocean dynamics both at the sea surface and at intrathermocline depths (0-1500m), and are presently investigated by means of model outputs, in-situ and satellite (surface) data, the latest being the only way to get high resolution and synoptic observations at planetary scale (e.g., thermal-band observations, future altimetric observations given by the SWOT satellite mission). The scientific question arising from this context is related to the role of the ocean surface for inferring informations on mesoscale and submesoscale vortices at depth. This study has also been motivated by the recent detection of subsurface eddies east of the Arabian Peninsula (PHYSINDIEN experiment - 2011).Using analytical models in the frame of the QG theory, we could describe the theoretical altimetric signature of non-drifting and of drifting subsurface eddies. Numerical experiments, using both coupled QG-SQG and primitive equations models, allowed us to investigate the surface expression of intrathermocline eddies interacting with baroclinic currents or evolving under planetary beta-effect. The eddy characteristics (radius, depth, thickness, velocity) were varied, to represent various oceanic examples (Meddies, Swoddies, Reddies, Peddies, Leddies). Idealized simulations with the ROMS model, confirming theoretical estimates, showed that drifting subsurface-intensified vortices can induce dipolar sea level anomalies, up to 3 cm. This result, compatibly with future SWOT measurement accuracies (about 2 cm), is a first step towards systematic and synoptic detection of subsurface vortices.
Managing Flap Vortices via Separation Control
NASA Technical Reports Server (NTRS)
Greenblatt, David
2006-01-01
A pilot study was conducted on a flapped semi-span model to investigate the concept and viability of near-wake vortex management by means of boundary layer separation control. Passive control was achieved using a simple fairing and active control was achieved via zero mass-flux blowing slots. Vortex sheet strength, estimated by integrating surface pressures, was used to predict vortex characteristics based on inviscid rollup relations and vortices trailing the flaps were mapped using a seven-hole probe. Separation control was found to have a marked effect on vortex location, strength, tangential velocity, axial velocity and size over a wide range of angles of attack and control conditions. In general, the vortex trends were well predicted by the inviscid rollup relations. Manipulation of the separated flow near the flap edges exerted significant control over either outboard or inboard edge vortices while producing small lift and moment excursions. Unsteady surface pressures indicated that dynamic separation and attachment control can be exploited to perturb vortices at wavelengths shorter than a typical wingspan. In summary, separation control has the potential for application to time-independent or time-dependent wake alleviation schemes, where the latter can be deployed to minimize adverse effects on ride-quality and dynamic structural loading.
Unsteady vortical structures in porous media flows
NASA Astrophysics Data System (ADS)
Finn, Justin; Apte, Sourabh; Wood, Brian
2011-11-01
The pore scale character of moderate Reynolds number, inertial flow through mono-disperse packed beds of spheres is examined using numerical experiments. Direct numerical simulations are performed for flow through (i) a periodic, 3 × 3 × 6 simple cubic arrangement at Rep = 529 , and (ii) a realistic randomly packed tube containing 326 spheres with dtube /dsp = 5 . 96 at Rep = 600 . At these Reynolds numbers, unsteady vortical regions are dominant features at the pore scale, and can have a profound effect on permeability and dispersion properties at the macro-scale. Despite similar Reynolds numbers and mean void fractions, the vortical structures observed in these two flows are remarkably different. The flow through the arranged packing is characterized by spatially and temporally periodic vortex-ring like structures, while the flow through the random packing contains many elongated helical vortices and a wider spectrum of space and time scales. The sensitive dependence of flow length and time scales and the local pore geometry is investigated using the DNS data. Funding: NSF project #0933857, Inertial Effects in Flow Through Porous Media.
Relative Equilibria of Identical Point Vortices
NASA Astrophysics Data System (ADS)
Aref, Hassan
2006-11-01
The problem of finding relative equilibria of identical point vortices is classical and was considered by Kelvin and J. J. Thomson almost immediately after the model had been introduced by Helmholtz in 1858. At the time relative equilibria of vortices were proposed as models of atoms. Apart from the intrinsic interest of the problem, and its mathematical challenge, such equilibria have been used as models for stationary states of distributed vortices, and have been observed in rotating superfluids, most recently in spectacular images of BECs. Simple equilibria such as regular polygons (both open and centered) were found and analyzed in the 19th century. Double rings and more recently triple rings have been found analytically. However, the numerically known relative equilibria continue to greatly outnumber those that are analytically known. A major numerical exploration was undertaken by Campell & Ziff in 1978 resulting in what is known as the Los Alamos Catalog. We will explore the results in this catalog and what we have learned since then, and present details on the quest for an analytical understanding of these intriguing states.
Two-particle vortices in graphene
NASA Astrophysics Data System (ADS)
Portnoi, Mikhail; Downing, Charles
We show that a pair of two-dimensional massless Dirac-Weyl fermions can form a bound state independently on the sign of the inter-particle interaction potential, as long as this potential decays at large distances faster than Kepler's inverse distance law. The coupling occurs only at the Dirac point, when the charge carriers lose their chirality. These bipartite states must have a non-zero internal angular momentum, meaning that they only exist as stationary vortices. This leads to the emergence of a new type of energetically-favorable quasiparticles: double-charged zero-energy vortices. Their bosonic nature allows condensation and gives rise to Majorana physics without invoking a superconductor. The presence of dark-matter-like silent immobile vortices explains a range of poorly understood experiments in gated graphene structures at low doping. This work was supported by EU H2020 RISE project CoExAN, EU FP7 ITN NOTEDEV and FP7 IRSES project InterNoM.
Self-Similar Compressible Free Vortices
NASA Technical Reports Server (NTRS)
vonEllenrieder, Karl
1998-01-01
Lie group methods are used to find both exact and numerical similarity solutions for compressible perturbations to all incompressible, two-dimensional, axisymmetric vortex reference flow. The reference flow vorticity satisfies an eigenvalue problem for which the solutions are a set of two-dimensional, self-similar, incompressible vortices. These solutions are augmented by deriving a conserved quantity for each eigenvalue, and identifying a Lie group which leaves the reference flow equations invariant. The partial differential equations governing the compressible perturbations to these reference flows are also invariant under the action of the same group. The similarity variables found with this group are used to determine the decay rates of the velocities and thermodynamic variables in the self-similar flows, and to reduce the governing partial differential equations to a set of ordinary differential equations. The ODE's are solved analytically and numerically for a Taylor vortex reference flow, and numerically for an Oseen vortex reference flow. The solutions are used to examine the dependencies of the temperature, density, entropy, dissipation and radial velocity on the Prandtl number. Also, experimental data on compressible free vortex flow are compared to the analytical results, the evolution of vortices from initial states which are not self-similar is discussed, and the energy transfer in a slightly-compressible vortex is considered.
Model flocks in a steady vortical flow.
Baggaley, A W
2015-05-01
We modify the standard Vicsek model to clearly distinguish between intrinsic noise due to imperfect alignment between organisms and extrinsic noise due to fluid motion. We then consider the effect of a steady vortical flow, the Taylor-Green vortex, on the dynamics of the flock, for various flow speeds, with a fixed intrinsic particle speed. We pay particular attention to the morphology of the flow, and quantify its filamentarity. Strikingly, above a critical flow speed there is a pronounced increase in the filamentarity of the flock, when compared to the zero-flow case. This is due to the fact that particles appear confined to areas of low vorticity; a familiar phenomena, commonly seen in the clustering of inertial particles in vortical flows. Hence, the cooperative motion of the particles gives them an effective inertia, which is seen to have a profound effect on the morphology of the flock, in the presence of external fluid motion. Finally, we investigate the angle between the flow and the particles direction of movement and find it follows a power-law distribution. PMID:26066260
Driven motion of vortices in superconductors
Crabtree, G.W.; Leaf, G.K.; Kaper, H.G.; Vinokur, V.M.; Koshelev, A.E.; Braun, D.W.; Levine, D.M.
1995-09-01
The driven motion of vortices in the solid vortex state is analyzed with the time-dependent Ginzburg-Landau equations. In large-scale numerical simulations, carried out on the IBM Scalable POWERparallel (SP) system at Argonne National Laboratory, many hundreds of vortices are followed as they move under the influence of a Lorentz force induced by a transport current in the presence of a planar defect (similar to a twin boundary in YBa{sub 2}CU{sub 3}O{sub 7}). Correlations in the positions and velocities of the vortices in plastic and elastic motion are identified and compared. Two types of plastic motion are observed. Organized plastic motion displaying long-range orientational correlation and shorter-range velocity correlation occurs when the driving forces are small compared to the pinning forces in the twin boundary. Disorganized plastic motion displaying no significant correlation in either the velocities or orientation of the vortex system occurs when the driving and pinning forces axe of the same order.
Model flocks in a steady vortical flow
NASA Astrophysics Data System (ADS)
Baggaley, A. W.
2015-05-01
We modify the standard Vicsek model to clearly distinguish between intrinsic noise due to imperfect alignment between organisms and extrinsic noise due to fluid motion. We then consider the effect of a steady vortical flow, the Taylor-Green vortex, on the dynamics of the flock, for various flow speeds, with a fixed intrinsic particle speed. We pay particular attention to the morphology of the flow, and quantify its filamentarity. Strikingly, above a critical flow speed there is a pronounced increase in the filamentarity of the flock, when compared to the zero-flow case. This is due to the fact that particles appear confined to areas of low vorticity; a familiar phenomena, commonly seen in the clustering of inertial particles in vortical flows. Hence, the cooperative motion of the particles gives them an effective inertia, which is seen to have a profound effect on the morphology of the flock, in the presence of external fluid motion. Finally, we investigate the angle between the flow and the particles direction of movement and find it follows a power-law distribution.
Long term changes in the polar vortices
NASA Astrophysics Data System (ADS)
Braathen, Geir O.
2015-04-01
As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented.
Waves and vortices in rotating stratified turbulence
NASA Astrophysics Data System (ADS)
Pouquet, Annick; Herbert, Corentin; Marino, Raffaele; Rosenberg, Duane
2015-04-01
The interactions between vortices and waves is a long-standing problem in fluid turbulence. It can lead to a self-sustaining process that is dominant, for example in pipe flows, and to the prediction of large-scale coherent structures such as baroclinic jets in planetary atmospheres, and it can also be used as a control tool for the onset of turbulence. Similarly, the dynamics of the atmosphere and the ocean is dominated by complex interactions between nonlinear eddies and waves due to a combination of rotation and stratification (characterized respectively by frequencies f and N), as well as shear layers. The waves are faster at large scales, and this leads to a quasi-geostrophic quasi-linear regime in which there is a balance between pressure gradient and the Coriolis and gravity forces. The range of scales in these geophysical flows before dissipation prevails is such that other regimes can arise in which turbulence comes into play, with the eddy turn-over time becoming comparable to the wave period, and for which isotropy recovers for sufficiently high Reynolds numbers. One may decompose the flow-- observational, experimental or numerical, in terms of the normal modes that it supports, i.e. the inertia-gravity waves and the (slow, zero frequency) vortical modes carrying the potential vorticity, thanks to the existence of a small parameter, as for example the fluctuation around a mean flow or the ratio of the wave period to the eddy turn-over time. In this context an ensemble of data sets of rotating stratified turbulence will be analyzed, stemming from accurate direct numerical simulations of the Boussinesq equations at high resolution, up to 40963 grid points, using high-performance computing. These flows all support a constant-flux bi-directional cascade of energy towards both the large scales and the small scales. The parameter space includes the Reynolds number, the Prandtl number(s), and the Rossby and Froude numbers, and a universal response to a variety
A Historical Profile of the Higgs Boson
Ellis, John; Gaillard, Mary K.; Nanopoulos, Dimitri V.
2012-01-31
The Higgs boson was postulated in 1964, and phenomenological studies of its possible production and decays started in the early 1970s, followed by studies of its possible productionin e{sup +} e{sup -}, {anti p}p and pp collisions, in particular. Until recently, the most sensitive searches for the Higgs boson were at LEP between 1989 and 2000, which have been complemented bysearches at the Fermilab Tevatron. The LHC has recently entered the hunt, excluding a Higgs boson over a large range of masses and revealing a tantalizing hint in the range 119 to125 GeV, and there are good prospects that the existence or otherwise of the Higgs boson will soon be established. One of the most attractive possibilities is that the Higgs bosonis accompanied by supersymmetry, though composite options have yet to be excluded. This article reviews some of the key historical developments in Higgs physics over the past half-century.
Higgs inflation from standard model criticality
NASA Astrophysics Data System (ADS)
Hamada, Yuta; Kawai, Hikaru; Oda, Kin-ya; Park, Seong Chan
2015-03-01
The observed Higgs mass MH=125.9 ±0.4 GeV leads to the criticality of the standard model, that is, the Higgs potential becomes flat around the scale 1 017 - 18 GeV for the top mass 171.3 GeV. Earlier we proposed a Higgs inflation scenario in which this criticality plays a crucial role. In this paper, we investigate the detailed cosmological predictions of this scenario in light of the latest Planck and BICEP2 results. We also consider the Higgs portal scalar dark matter model, and compute the Higgs one-loop effective potential with the two-loop renormalization group improvement. We find a constraint on the coupling between the Higgs boson and dark matter which depends on the inflationary parameters.
Surfzone vorticity in the presence of extreme bathymetric variability
NASA Astrophysics Data System (ADS)
Clark, D.; Elgar, S.; Raubenheimer, B.
2014-12-01
Surfzone vorticity was measured at Duck, NC using a novel 5-m diameter vorticity sensor deployed in 1.75 m water depth. During the 4-week deployment the initially alongshore uniform bathymetry developed 200-m long mega-cusps with alongshore vertical changes of 1.5 m or more. When waves were small and the vorticity sensor was seaward of the surfzone, vorticity variance and mean vorticity varied with the tidally modulated water depth, consistent with a net seaward flux of surfzone-generated vorticity. Vorticity variance increased with incident wave heights up to 2-m. However, vorticity variance remained relatively constant for incident wave heights above 2-m, and suggests that eddy energy may become saturated in the inner surfzone during large wave events. In the presence of mega-cusps the mean vorticity (shear) is often large and generated by bathymetrically controlled rip currents, while vorticity variance remains strongly correlated with the incident wave height. Funded by NSF, ASD(R&E), and WHOI Coastal Ocean Institute.
Large Deviation Statistics of Vorticity Stretching in Isotropic Turbulence
NASA Astrophysics Data System (ADS)
Johnson, Perry; Meneveau, Charles
2015-11-01
A key feature of 3D fluid turbulence is the stretching/re-alignment of vorticity by the action of the strain-rate. It is shown using the cumulant-generating function that cumulative vorticity stretching along a Lagrangian path in isotropic turbulence behaves statistically like a sum of i.i.d. variables. The Cramer function for vorticity stretching is computed from the JHTDB isotropic DNS (Reλ = 430) and compared to those of the finite-time Lyapunov exponents (FTLE) for material deformation. As expected the mean cumulative vorticity stretching is slightly less than that of the most-stretched material line (largest FTLE), due to the vorticity's preferential alignment with the second-largest eigenvalue of strain-rate and the material line's preferential alignment with the largest eigenvalue. However, the vorticity stretching tends to be significantly larger than the second-largest FTLE, and the Cramer functions reveal that the statistics of vorticity stretching fluctuations are more similar to those of largest FTLE. A model Fokker-Planck equation is constructed by approximating the viscous destruction of vorticity with a deterministic non-linear relaxation law matching conditional statistics, while the fluctuations in vorticity stretching are modelled by stochastic noise matching the statistics encoded in the Cramer function. The model predicts a stretched-exponential tail for the vorticity magnitude PDF, with good agreement for the exponent but significant error (30-40%) in the pre-factor. Supported by NSF Graduate Fellowship (DGE-1232825) and NSF Grant CMMI-0941530.
AGT relations for abelian quiver gauge theories on ALE spaces
NASA Astrophysics Data System (ADS)
Pedrini, Mattia; Sala, Francesco; Szabo, Richard J.
2016-05-01
We construct level one dominant representations of the affine Kac-Moody algebra gl̂k on the equivariant cohomology groups of moduli spaces of rank one framed sheaves on the orbifold compactification of the minimal resolution Xk of the Ak-1 toric singularity C2 /Zk. We show that the direct sum of the fundamental classes of these moduli spaces is a Whittaker vector for gl̂k, which proves the AGT correspondence for pure N = 2 U(1) gauge theory on Xk. We consider Carlsson-Okounkov type Ext-bundles over products of the moduli spaces and use their Euler classes to define vertex operators. Under the decomposition gl̂k ≃ h ⊕sl̂k, these vertex operators decompose as products of bosonic exponentials associated to the Heisenberg algebra h and primary fields of sl̂k. We use these operators to prove the AGT correspondence for N = 2 superconformal abelian quiver gauge theories on Xk.
Fast non-Abelian geometric gates via transitionless quantum driving
Zhang, J.; Kyaw, Thi Ha; Tong, D. M.; Sjöqvist, Erik; Kwek, Leong-Chuan
2015-01-01
A practical quantum computer must be capable of performing high fidelity quantum gates on a set of quantum bits (qubits). In the presence of noise, the realization of such gates poses daunting challenges. Geometric phases, which possess intrinsic noise-tolerant features, hold the promise for performing robust quantum computation. In particular, quantum holonomies, i.e., non-Abelian geometric phases, naturally lead to universal quantum computation due to their non-commutativity. Although quantum gates based on adiabatic holonomies have already been proposed, the slow evolution eventually compromises qubit coherence and computational power. Here, we propose a general approach to speed up an implementation of adiabatic holonomic gates by using transitionless driving techniques and show how such a universal set of fast geometric quantum gates in a superconducting circuit architecture can be obtained in an all-geometric approach. Compared with standard non-adiabatic holonomic quantum computation, the holonomies obtained in our approach tends asymptotically to those of the adiabatic approach in the long run-time limit and thus might open up a new horizon for realizing a practical quantum computer. PMID:26687580
Fast non-Abelian geometric gates via transitionless quantum driving
NASA Astrophysics Data System (ADS)
Zhang, J.; Kyaw, Thi Ha; Tong, D. M.; Sjöqvist, Erik; Kwek, Leong-Chuan
2015-12-01
A practical quantum computer must be capable of performing high fidelity quantum gates on a set of quantum bits (qubits). In the presence of noise, the realization of such gates poses daunting challenges. Geometric phases, which possess intrinsic noise-tolerant features, hold the promise for performing robust quantum computation. In particular, quantum holonomies, i.e., non-Abelian geometric phases, naturally lead to universal quantum computation due to their non-commutativity. Although quantum gates based on adiabatic holonomies have already been proposed, the slow evolution eventually compromises qubit coherence and computational power. Here, we propose a general approach to speed up an implementation of adiabatic holonomic gates by using transitionless driving techniques and show how such a universal set of fast geometric quantum gates in a superconducting circuit architecture can be obtained in an all-geometric approach. Compared with standard non-adiabatic holonomic quantum computation, the holonomies obtained in our approach tends asymptotically to those of the adiabatic approach in the long run-time limit and thus might open up a new horizon for realizing a practical quantum computer.
Non-Abelian statistics of Luttinger holes in quantum wells
NASA Astrophysics Data System (ADS)
Simion, George; Lyanda-Geller, Yuli
2015-03-01
Non-Abelian quasiparticle excitations represent a key element of topologically protected quantum computing. Such exotic states appear in fractional quantum Hall (FQH) effect as eigenstates of N-body interaction potential. These potentials can be obtained by renormalization of electron-electron interactions in the presence of Landau level (LL) mixing. The properties of valence band holes makes them fundamentally different from electrons. In the presence of magnetic field, low-lying states do not exhibit fan-like diagram and several of the levels cross. Variation of magnetic field in the vicinity of level crossings serves as a knob that tunes LL mixing and enhances the 3-body interaction. 1 / 2 filling factor FQH is a state that was not observed in electron liquid, but has been observed for holes. The properties of the two dimensional charged quantum hole liquid in the presence of magnetic field are studied using the spherical geometry. The properties of the novel 1 / 2 state are discussed. Research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-SC0010544.
Topologically Massive Non-Abelian Theory:. Superfield Approach
NASA Astrophysics Data System (ADS)
Krishna, S.; Shukla, A.; Malik, R. P.
We apply the well-established techniques of geometrical superfield approach to Becchi-Rouet-Stora-Tyutin (BRST) formalism in the context of four (3+1)-dimensional (4D) dynamical non-Abelian 2-form gauge theory by exploiting its inherent "scalar" and "vector" gauge symmetry transformations and derive the corresponding off-shell nilpotent and absolutely anticommuting BRST and anti-BRST symmetry transformations. Our approach leads to the derivation of three (anti-)BRST invariant Curci-Ferrari (CF)-type restrictions that are found to be responsible for the absolute anticommutativity of the BRST and anti-BRST symmetry transformations. We derive the coupled Lagrangian densities that respect the (anti-)BRST symmetry transformations corresponding to the "vector" gauge transformations. We also capture the (anti-)BRST invariance of the CF-type restrictions and coupled Lagrangian densities within the framework of our superfield approach. We obtain, furthermore, the off-shell nilpotent (anti-)BRST symmetry transformations when the (anti-)BRST symmetry transformations corresponding to the "scalar" and "vector" gauge symmetries are merged together. These off-shell nilpotent "merged" (anti-)BRST symmetry transformations are, however, found to be non-anticommuting in nature.
Fast non-Abelian geometric gates via transitionless quantum driving.
Zhang, J; Kyaw, Thi Ha; Tong, D M; Sjöqvist, Erik; Kwek, Leong-Chuan
2015-01-01
A practical quantum computer must be capable of performing high fidelity quantum gates on a set of quantum bits (qubits). In the presence of noise, the realization of such gates poses daunting challenges. Geometric phases, which possess intrinsic noise-tolerant features, hold the promise for performing robust quantum computation. In particular, quantum holonomies, i.e., non-Abelian geometric phases, naturally lead to universal quantum computation due to their non-commutativity. Although quantum gates based on adiabatic holonomies have already been proposed, the slow evolution eventually compromises qubit coherence and computational power. Here, we propose a general approach to speed up an implementation of adiabatic holonomic gates by using transitionless driving techniques and show how such a universal set of fast geometric quantum gates in a superconducting circuit architecture can be obtained in an all-geometric approach. Compared with standard non-adiabatic holonomic quantum computation, the holonomies obtained in our approach tends asymptotically to those of the adiabatic approach in the long run-time limit and thus might open up a new horizon for realizing a practical quantum computer. PMID:26687580
Electroweak Baryogenesis with Anomalous Higgs Couplings
NASA Astrophysics Data System (ADS)
Kobakhidze, Archil; Wu, Lei; Yue, Jason
2016-07-01
In non-linear realisation of the electroweak gauge symmetry, the LHC Higgs boson can be assumed to be a singlet under SU(2)L ⊗ U(1)Y. In such scenario, the Standard Model particle content can be kept but new sets of couplings are allowed. We identify a range of anomalous Higgs cubic and the 𝒞𝒫-violating Higgs-top quark couplings that leads to first order phase transition and successful baryogenesis at the electroweak scale.
Recent Higgs results from the ATLAS experiment
Brendlinger, Kurt; Collaboration: ATLAS Collaboration
2014-06-24
This paper presents recent results on the Higgs boson from the ATLAS experiment at the Large Hadron Collider. The Collaboration reports on measurements of the signal strength, couplings, and spin of the Higgs in several decay channels. We find all measurements to be consistent with Standard Model predictions. The Higgs branching fraction to invisible particles is constrained and no evidence of physics beyond the Standard Model is found.
Emergent two-Higgs doublet models
NASA Astrophysics Data System (ADS)
Abe, Tomohiro; Omura, Yuji
2016-08-01
We investigate origin of three features that are often assumed in analysis of two-Higgs doublet models: (i) softly broken Z 2 symmetry, (ii) CP invariant Higgs potential, and (iii) degenerated mass spectra. We extend electroweak gauge symmetry, introducing extra gauge symmetry and extra scalars, and we show that our models effectively derive two-Higgs doublet models at low energy which naturally hold the three features. We also find that the models can solve the strong CP problem.
The Higgs Boson for the Masses?
Quigg, Chris
2012-04-04
The Higgs boson is the object of one of the greatest campaigns in the history of particle physics and a pop-culture icon. But what is a Higgs boson, and what would we like it to do for us? What will we understand after a discovery that we don't understand before? How would the world be different if nothing did the job of the Higgs boson? We will explore all these questions and more through demonstration, simulation, and audience participation.
Benchmarks for Higgs effective theory: extended Higgs sectors
NASA Astrophysics Data System (ADS)
Gorbahn, Martin; No, Jose Miguel; Sanz, Verónica
2015-10-01
Precise measurements of SM particles properties at the LHC allows to look for heavy New Physics in the context of an Effective Field Theory (EFT). These searches, however, often rely on kinematic regions where the validity of the EFT may be compromised. In this paper we propose to address this issue by comparing with benchmark models. The connection between models and their manifestations as EFTs at low energies allows us to quantify the breakdown of the EFT, and describe ways to combine different sources of constraints beyond Higgs physics. To illustrate these techniques, in this paper we propose a set of benchmark models based on extensions of the Higgs sector, namely the inclusion of a singlet, a dilaton and generic 2HDMs. We obtain the matching between these models and the EFT involving the Higgs, electroweak bosons and fermions. We then describe current and future indirect and direct constraints, consider the effect of correlations among the coefficients within models, and discuss the validity of the EFT.
CP violation in heavy MSSM Higgs scenarios
Carena, M.; Ellis, J.; Lee, J. S.; Pilaftsis, A.; Wagner, C. E. M.
2016-02-18
We introduce and explore new heavy Higgs scenarios in the Minimal Supersymmetric Standard Model (MSSM) with explicit CP violation, which have important phenomenological implications that may be testable at the LHC. For soft supersymmetry-breaking scales MS above a few TeV and a charged Higgs boson mass MH+ above a few hundred GeV, new physics effects including those from explicit CP violation decouple from the light Higgs boson sector. However, such effects can significantly alter the phenomenology of the heavy Higgs bosons while still being consistent with constraints from low-energy observables, for instance electric dipole moments. To consider scenarios with amore » charged Higgs boson much heavier than the Standard Model (SM) particles but much lighter than the supersymmetric particles, we revisit previous calculations of the MSSM Higgs sector. We compute the Higgs boson masses in the presence of CP violating phases, implementing improved matching and renormalization-group (RG) effects, as well as two-loop RG effects from the effective two-Higgs Doublet Model (2HDM) scale MH± to the scale MS. Here, we illustrate the possibility of non-decoupling CP-violating effects in the heavy Higgs sector using new benchmark scenarios named.« less
Higgs portals to pulsar collapse
NASA Astrophysics Data System (ADS)
Bramante, Joseph; Elahi, Fatemeh
2015-06-01
Pulsars apparently missing from the Galactic center could have been destroyed by asymmetric fermionic dark matter (mX=1 - 100 GeV ) coupled to a light scalar (mϕ=5 - 20 MeV ), which mixes with the Higgs boson. We point out that this pulsar-collapsing dark sector can resolve the core-cusp problem and will either be excluded or discovered by upcoming direct detection experiments. Another implication is a maximum pulsar age curve that increases with distance from the Galactic center, with a normalization that depends on the couplings and masses of dark sector particles. In addition, we use old pulsars outside the Galactic center to place bounds on asymmetric Higgs portal models.
Lincoln, Don
2014-04-28
With the discovery of what looks to be the Higgs boson, LHC researchers are turning their attention to the next big question, which is the predicted mass of the newly discovered particles. When the effects of quantum mechanics is taken into account, the mass of the Higgs boson should be incredibly high...perhaps upwards of a quadrillion times higher than what was observed. In this video, Fermilab's Dr. Don Lincoln explains how it is that the theory predicts that the mass is so large and gives at least one possible theoretical idea that might solve the problem. Whether the proposed idea is the answer or not, this question must be answered by experiments at the LHC or today's entire theoretical paradigm could be in jeopardy.
Draper, Patrick; Liu Tao; Wagner, Carlos E. M.; Wang, Lian-Tao; Zhang Hao
2011-03-25
We study a limit of the nearly Peccei-Quinn-symmetric next-to-minimal supersymmetric standard model possessing novel Higgs and dark matter (DM) properties. In this scenario, there naturally coexist three light singletlike particles: a scalar, a pseudoscalar, and a singlinolike DM candidate, all with masses of order 0.1-10 GeV. The decay of a standard model-like Higgs boson to pairs of the light scalars or pseudoscalars is generically suppressed, avoiding constraints from collider searches for these channels. For a certain parameter window annihilation into the light pseudoscalar and exchange of the light scalar with nucleons allow the singlino to achieve the correct relic density and a large direct-detection cross section consistent with the DM direct-detection experiments, CoGeNT and DAMA/LIBRA, preferred region simultaneously. This parameter space is consistent with experimental constraints from LEP, the Tevatron, {Upsilon}, and flavor physics.
The Higgs Machine Learning Challenge
NASA Astrophysics Data System (ADS)
Adam-Bourdarios, C.; Cowan, G.; Germain-Renaud, C.; Guyon, I.; Kégl, B.; Rousseau, D.
2015-12-01
The Higgs Machine Learning Challenge was an open data analysis competition that took place between May and September 2014. Samples of simulated data from the ATLAS Experiment at the LHC corresponding to signal events with Higgs bosons decaying to τ+τ- together with background events were made available to the public through the website of the data science organization Kaggle (kaggle.com). Participants attempted to identify the search region in a space of 30 kinematic variables that would maximize the expected discovery significance of the signal process. One of the primary goals of the Challenge was to promote communication of new ideas between the Machine Learning (ML) and HEP communities. In this regard it was a resounding success, with almost 2,000 participants from HEP, ML and other areas. The process of understanding and integrating the new ideas, particularly from ML into HEP, is currently underway.
Lincoln, Don
2014-06-03
With the discovery of what looks to be the Higgs boson, LHC researchers are turning their attention to the next big question, which is the predicted mass of the newly discovered particles. When the effects of quantum mechanics is taken into account, the mass of the Higgs boson should be incredibly high...perhaps upwards of a quadrillion times higher than what was observed. In this video, Fermilab's Dr. Don Lincoln explains how it is that the theory predicts that the mass is so large and gives at least one possible theoretical idea that might solve the problem. Whether the proposed idea is the answer or not, this question must be answered by experiments at the LHC or today's entire theoretical paradigm could be in jeopardy.
NASA Astrophysics Data System (ADS)
Nogueira, Flavio S.; Sudbø, Asle; Eremin, Ilya
2015-12-01
We demonstrate that the Higgs mechanism in three-dimensional topological superconductors exhibits unique features with experimentally observable consequences. The Higgs model we discuss has two superconducting components and an axionlike magnetoelectric term with the phase difference of the superconducting order parameters playing the role of the axion field. Due to this additional term, quantum electromagnetic and phase fluctuations lead to a robust topologically nontrivial state that holds also in the presence of interactions. In this sense, we show that the renormalization flow of the topologically nontrivial phase cannot be continuously deformed into a topologically nontrivial one. One consequence of our analysis of quantum critical fluctuations is the possibility of having a first-order phase transition in the bulk and a second-order phase transition on the surface. We also explore another consequence of the axionic Higgs electrodynamics, namely, the anomalous Hall effect. In the low-frequency London regime an anomalous Hall effect is induced in the presence of an applied electric field parallel to the surface. This anomalous Hall current is induced by a Lorentz-like force arising from the axion term, and it involves the relative superfluid velocity of the superconducting components. The anomalous Hall current has a negative sign, a situation reminiscent of but quite distinct in physical origin from the anomalous Hall effect observed in high-Tc superconductors. In contrast to the latter, the anomalous Hall effect in topological superconductors is nondissipative and occurs in the absence of vortices.
Zombie Vortices: Angular Momentum Transport and Planetesimal Formation
NASA Astrophysics Data System (ADS)
Barranco, Joseph; Marcus, Philip; Pei, Suyang; Jiang, Chung-Hsiang; Hassanzadeh, Pedram; Lecoanet, Daniel
2014-11-01
Zombie vortices may fill the dead zones of protoplanetary disks, where they may play important roles in star and planet formation. We will investigate this new, purely hydrodynamic instability and explore the conditions necessary to resurrect the dead zone and fill it with large amplitude vortices that may transport angular momentum and allow mass to accrete onto the protostar. One unresolved issue is whether angular momentum transport is mediated via asymmetries in the vortices, vortex-vortex interactions, or acoustic waves launched by the vortices. Vortices may also play a crucial role in the formation of planetesimals, the building blocks of planets. It is still an open question how grains grow to kilometer-size. We will investigate the interactions of dust with vortices generated via our new hydrodynamic instability, and bridge the gap between micron-sized grains and kilometer-sized planetesimals. Supported by NSF AST-1010052.
Numerical studies of the margin of vortices with decaying cores
NASA Technical Reports Server (NTRS)
Liu, G. C.; Ting, L.
1986-01-01
The merging of vortices to a single one is a canonical incompressible viscous flow problem. The merging process begins when the core sizes or the vortices are comparable to their distances and ends when the contour lines of constant vorticity lines are circularized around one center. Approximate solutions to this problem are constructed by adapting the asymptotic solutions for distinct vortices. For the early stage of merging, the next-order terms in the asymptotic solutions are added to the leading term. For the later stage of merging, the vorticity distribution is reinitialized by vortices with overlapping core structures guided by the 'rule of merging' and the velocity of the 'vortex centers' are then defined by a minimum principle. To show the accuracy of the approximate solution, it is compared with the finite-difference solution.
On streamwise vortices in turbulent wakes of cylinders
NASA Astrophysics Data System (ADS)
Bays-Muchmore, B.; Ahmed, A.
1993-02-01
Flow-visualization methods were used to explore the structure of streamwise vortices and their interactions with the von Kármán vortices in the immediate wakes of cylinders. The experiments were conducted in a water tunnel at Reynolds numbers from 330-21 000 based on cylinder diameter. Over this entire range of Reynolds number, pairs of counter-rotating streamwise vortices were observed immediately behind the cylinders, with a mean spanwise spacing of approximately one pair per diameter. The streamwise vortices significantly distorted the von Kármán vortices, but only on their upstream-facing sides. The cylinder near-surface-flow topology was found to include a secondary separation line containing ``dominant-foci structures'' whose spanwise locations correlated with those of the streamwise vortices.
On streamwise vortices in turbulent wakes of cylinders
NASA Astrophysics Data System (ADS)
Bays-Muchmore, B.; Ahmed, A.
1993-02-01
Flow-visualization methods were used to explore the structure of streamwise vortices and their interactions with the von Karman vortices in the immediate wakes of cylinders. The experiments were conducted in a water tunnel at Reynolds numbers from 330-21,000 based on cylinder diameter. Over this entire range of Reynolds number, pairs of counter-rotating streamwise vortices were observed immediately behind the cylinders, with a mean spanwise spacing of approximately one pair per diameter. The streamwise vortices significantly distorted the von Karman vortices, but only on their upstream-facing sides. The cylinder near-surface-flow topology was found to include a secondary separation line containing 'dominant-foci structures' whose spanwise locations correlated with those of the streamwise vortices.
Analysis of LIMS data by potential vorticity inversion
NASA Technical Reports Server (NTRS)
Robinson, Walter A.
1988-01-01
This paper analyzes LIMS data for a minor warming of January 1979 by potential vorticity inversion, to investigate how flows in the middle atmosphere were determined. The inversion problem of calculating the flow from the potential vorticity is solved repeatedly, including and excluding different portions of the potential vorticity, thus revealing which bits of potential vorticity were important in determining the flow at a time and location of interest. The results of the analysis of LIMS data indicate that the middle stratospheric flow is dominated by potential vorticity that is local in height and in latitude, while planetary-scale mesospheric flows are primarily induced by potential vorticity in the stratosphere. A possible explanation for this difference is proposed.
Alvarez Gonzalez, Barbara; /Oviedo U.
2010-06-01
We present the latest CDF searches for the Standard Model Higgs boson with 1.96 TeV center-of-mass energy collisions produced at the Fermilab Tevatron. The data was collected with the CDF II detector at the Tevatron collider and correspond to an integrated luminosity from 2 to 4.8 1/fb. To achieve maximal sensitivity, many channels are analyzed including final states from gluon fusion, vector boson fusion, and associated production with W and Z bosons.
NASA Astrophysics Data System (ADS)
Hassanzadeh, Pedram
Large coherent vortices are abundant in geophysical and astrophysical flows. They play significant roles in the Earth's oceans and atmosphere, the atmosphere of gas giants, such as Jupiter, and the protoplanetary disks around forming stars. These vortices are essentially three-dimensional (3D) and baroclinic, and their dynamics are strongly influenced by the rotation and density stratification of their environments. This work focuses on improving our understanding of the physics of 3D baroclinic vortices in rotating and continuously stratified flows using 3D spectral simulations of the Boussinesq equations, as well as simplified mathematical models. The first chapter discusses the big picture and summarizes the results of this work. In Chapter 2, we derive a relationship for the aspect ratio (i.e., vertical half-thickness over horizontal length scale) of steady and slowly-evolving baroclinic vortices in rotating stratified fluids. We show that the aspect ratio is a function of the Brunt-Vaisala frequencies within the vortex and outside the vortex, the Coriolis parameter, and the Rossby number of the vortex. This equation is basically the gradient-wind equation integrated over the vortex, and is significantly different from the previously proposed scaling laws that find the aspect ratio to be only a function of the properties of the background flow, and independent of the dynamics of the vortex. Our relation is valid for cyclones and anticyclones in either the cyclostrophic or geostrophic regimes; it works with vortices in Boussinesq fluids or ideal gases, and non-uniform background density gradient. The relation for the aspect ratio has many consequences for quasi-equilibrium vortices in rotating stratified flows. For example, cyclones must have interiors more stratified than the background flow (i.e., super-stratified), and weak anticyclones must have interiors less stratified than the background (i.e., sub-stratified). In addition, this equation is useful to
Neutrino Oscillations, the Higgs Boson, and the Private Higgs Model
NASA Astrophysics Data System (ADS)
BenTov, Jonathan
"CESR, PEP, PETRA, ISABELLE, p-bar p colliders, LEP, the tevatron, and ep machines are at various levels of design or construction. They will study the properties of b-matter, see weak intermediaries, and perhaps find the t-quark and the Higgs boson. Never before was there such a bestiary waiting to be discovered; and what surprises will be found!" - S. L. Glashow ("The Future of Elementary Particle Physics," Quarks and Leptons, NATO Advanced Study Institutes Series Volume 61, 1980, pp 687-713) The situation in 1980 was clearly different from the present situation in 2013, in which we face the very real possibilty that no new degrees of freedom will ever again be within reach of a collider. In an intriguing twist of fate, this very fact results in a sharp paradox for fundamental physics: the Higgs mass should be MP/m h ˜ 1017 times larger than it actually is, and the vacuum energy density of the universe should be (M P/A)4 ˜ (1031)4 times larger than it actually is, and apparently nature refuses to give us any more clues as to why. These together are what I would call the main problem of 21st century physics: despite all of the predictive success of particle physics so far, we must find a way to suitably modify the rules of quantum field theory, lest we accept the unproductive defeatist attitude that our universe is simply fine-tuned. In the meantime, there is much interesting work to be done in more "traditional" particle physics: we have learned that neutrinos actually have tiny but nonzero masses, which is clear and unambiguous evidence for physics beyond the Standard Model. I will allocate the first third of this document to phenomena related to neutrino oscillations. In particular, I would like to argue that some of the apparent differences between neutrino mixing and quark mixing are to an extent illusory, and actually many aspects of the two sectors can be understood in a coherent framework for extending the Standard Model. The remaining two-thirds of this
Observational signatures of Higgs inflation
NASA Astrophysics Data System (ADS)
Enckell, Vera-Maria; Enqvist, Kari; Nurmi, Sami
2016-07-01
We investigate the dependency of Higgs inflation on the non-renormalisable matching between the low energy Standard Model limit and the inflationary regime at high energies. We show that for the top mass range mt gtrsim 171.8 GeV the scenario robustly predicts the spectral index ns simeq 0.97 and the tensor-to-scalar ratio r simeq 0.003. The matching is however non-trivial, even the best-fit values mh = 125.09 GeV and mt = 173.21 GeV require a jump δλ ~ 0.01 in the Higgs coupling below the inflationary scale. For mt lesssim 171.8 GeV, the matching may generate a feature in the inflationary potential. In this case the predicted values of ns and r vary but the model is still falsifiable. For example, a detection of negative running of spectral index at level αs lesssim ‑0.01 would rule out Higgs inflation.
Exploring holographic Composite Higgs models
NASA Astrophysics Data System (ADS)
Croon, Djuna; Dillon, Barry M.; Huber, Stephan J.; Sanz, Veronica
2016-07-01
Simple Composite Higgs models predict new vector-like fermions not too far from the electroweak scale, yet LHC limits are now sensitive to the TeV scale. Motivated by this tension, we explore the holographic dual of the minimal model, MCHM5, to try and alleviate this tension without increasing the fine-tuning in the Higgs potential. Interestingly, we find that lowering the UV cutoff in the 5D picture allows for heavier top partners and less fine-tuning. In the 4D dual this corresponds to increasing the number of "colours" N , thus increasing the decay constant of the Goldstone Higgs. This is essentially a `Little Randall-Sundrum Model', which are known to reduce some flavour and electroweak constraints. Furthermore, in anticipation of the ongoing efforts at the LHC to put bounds on the top Yukawa, we demonstrate that deviations from the SM can be suppressed or enhanced with respect to what is expected from mere symmetry arguments in 4D. We conclude that the 5D holographic realisation of the MCHM5 with a small UV cutoff is not in tension with the current experimental data.
Holographic bounds and Higgs inflation
NASA Astrophysics Data System (ADS)
Horvat, R.
2011-05-01
In a recently proposed scenario for primordial inflation, where the Standard Model (SM) Higgs boson plays a role of the inflation field, an effective field theory (EFT) approach is the most convenient for working out the consequences of breaking of perturbative unitarity, caused by the strong coupling of the Higgs field to the Ricci scalar. The domain of validity of the EFT approach is given by the ultraviolet (UV) cutoff, which, roughly speaking, should always exceed the Hubble parameter in the course of inflation. On the other hand, applying the trusted principles of quantum gravity to a local EFT demands that it should only be used to describe states in a region larger than their corresponding Schwarschild radius, manifesting thus a sort of UV/IR correspondence. We consider both constraints on EFT, to ascertain which models of the SM Higgs inflation are able to simultaneously comply with them. We also show that if the gravitational coupling evolves with the scale factor, the holographic constraint can be alleviated significantly with minimal set of canonical assumptions, by forcing the said coupling to be asymptotically free.
Potential Vorticity as a Diagnostic for the Mars Polar Vortex
NASA Astrophysics Data System (ADS)
McConnochie, T. H.; Conrath, B. J.; Gierasch, P. J.; Banfield, D.; Smith, M. D.
2009-05-01
Polar vortices dominate the dynamics of the winter mid- and polar latitudes in the martian atmosphere as well as in the terrestrial stratosphere. Polar vortices have also been observed on Venus (Taylor, 2002), Jupiter (Orton, 2002), Saturn (Fletcher, 2008), and Titan (Teanby, 2008). Potential vorticity is the analysis quantity of choice for the terrestrial polar vortices because its vertical component distills the most important features of the wind and temperature fields into a single scalar variable; because it is a conserved tracer under adiabatic conditions; because it serves as the medium for Rossby waves; and because steep potential vorticity gradients are observed to be correlated with steep gradients in the concentrations of chemical species. Using potential vorticity derived from Mars Global Surveyor Thermal Emission Spectrometer (TES) temperature soundings, we compare the structure of the martian polar vortices to those of the earth. We find that the northern martian winter polar vortex, just like its terrestrial conterpart, is bounded by a region of very steep potential vorticity gradients and is surrounded by a "surf zone", a region of low potential vorticity and very low potential vorticity gradients. The surf zone concept, as first described for the terrestrial stratosphere by McIntyre and Palmer (1983), implies persistent Rossby wave breaking. In the vicinity of the northern polar vortex, the TES data set provides some examples of local gradient reversals that are suggestive of wave breaking. There is also one case of possible large-scale wave breaking accompanied by an abrupt polar warming. The martian southern polar vortex, unlike its terrestrial counterpart and unlike the northern martian polar vortex, lacks a distinct boundary between the polar vortex and a surf zone. Instead, the potential vorticity field is highly disorganized with local gradient reversals throughout the middle and polar latitudes. In the zonal mean, the southern winter
Vortical superlattices in a gold nanorods' self-assembled monolayer
NASA Astrophysics Data System (ADS)
Xie, Yong; Liang, Yujia; Chen, Dongxue; Wu, Xiaochun; Dai, Luru; Liu, Qian
2014-02-01
This paper describes the novel vortical self-assembly of CTAB-capped gold nanorods. Representative left-hand, radial, and right-hand vortices are shown. Micelles formed by CTAB molecules enhance the organized self-assembly process. The drag force of solvent flow and dynamic vortex flow in the thin solvent layer are thought to be responsible for the final vortical superlattices. FDTD simulation suggests these structures have potential applications in nanofocusing and polarized light response.
Resource Article: Experiments with Vortices in Superfluid Atomic Gases
NASA Astrophysics Data System (ADS)
Anderson, Brian P.
2010-12-01
Observations of quantized vortices in dilute-gas Bose-Einstein condensates were first reported in 1999. Over the next 10 years, more than 70 papers describing experiments involving vortices in superfluid atomic gases were published in scientific journals. This resource article provides a guide to the published experimental studies related to quantized vortices in atomic Bose-Einstein condensates and superfluid Fermi gases. A BibTex-formatted bibliography document listing these published studies is also available electronically.
Universal topological quantum computation from a superconductor/Abelian quantum Hall heterostructure
NASA Astrophysics Data System (ADS)
Mong, Roger
2014-03-01
Non-Abelian anyons promise to reveal spectacular features of quantum mechanics that could ultimately provide the foundation for a decoherence-free quantum computer. A key breakthrough in the pursuit of these exotic particles originated from Read and Green's observation that the Moore-Read quantum Hall state and a (relatively simple) two-dimensional p + ip superconductor both support so-called Ising non-Abelian anyons. Here we establish a similar correspondence between the Z3 Read-Rezayi quantum Hall state and a novel two-dimensional superconductor in which charge- 2 e Cooper pairs are built from fractionalized quasiparticles. In particular, both phases harbor Fibonacci anyons that--unlike Ising anyons--allow for universal topological quantum computation solely through braiding. Using a variant of Teo and Kane's construction of non-Abelian phases from weakly coupled chains, we provide a blueprint for such a superconductor using Abelian quantum Hall states interlaced with an array of superconducting islands. These results imply that one can, in principle, combine well-understood and widely available phases of matter to realize non-Abelian anyons with universal braid statistics.
Bilayer quantum Hall phase transitions and the orbifold non-Abelian fractional quantum Hall states
Barkeshli, Maissam; Wen Xiaogang
2011-09-15
We study continuous quantum phase transitions that can occur in bilayer fractional quantum Hall (FQH) systems as the interlayer tunneling and interlayer repulsion are tuned. We introduce a slave-particle gauge theory description of a series of continuous transitions from the (ppq) Abelian bilayer states to a set of non-Abelian FQH states, which we dub orbifold FQH states, of which the Z{sub 4} parafermion (Read-Rezayi) state is a special case. This provides an example in which Z{sub 2} electron fractionalization leads to non-Abelian topological phases. The naive ''ideal'' wave functions and ideal Hamiltonians associated with these orbifold states do not in general correspond to incompressible phases but, instead, lie at a nearby critical point. We discuss this unusual situation from the perspective of the pattern-of-zeros/vertex algebra frameworks and discuss implications for the conceptual foundations of these approaches. Due to the proximity in the phase diagram of these non-Abelian states to the (ppq) bilayer states, they may be experimentally relevant, both as candidates for describing the plateaus in single-layer systems at filling fractions 8/3 and 12/5 and as a way to tune to non-Abelian states in double-layer or wide quantum wells.
Non-abelian dynamics in first-order cosmological phase transitions
Johnson, Mikkel B.; Kisslinger, Leonard S.; Henley, Ernest M.; Hwang, P. W-Y.; Stevens, T.
2004-01-01
Bubble collisions in cosmological phase transitions are explored, taking the non-abelian character of the gauge fields into account. Both the QCD and electroweak phase transitions are considered. Numerical solutions of the field equations in several limits are presented. The investigations reported in this talk have been motivated by an interest in studying cosmological phase transitions quantitatively, taking the non-abelian character of the gauge fields into account. Ultimately, we hope to identify observable consequences of cosmological phase transitions. First-order phase transitions proceed by nucleation of bubbles of the broken phase in the background of the symmetric phase. Bubble collisions are of special interest, as they may lead to observable effects such as correlations in the cosmic microwave background (CMB) or as seeds of galactic and extra-galactic magnetic fields. The quantum chromodynamic (QCD) and the electroweak (EW) phase transitions are both candidates of interest in these respects. The Lagrangian driving both the QCD and the EW phase transitions are essentially known and make it possible to approach the physics of the phase transitions from first principles. However, a difficulty to making reliable predictions is that the fundamental guage fields in both these instances are non-abelian: the gluon field in QCD and the W and Z fields in the EW case. The quantitative role of non-abelian fields in cosmological phase transitions is poorly known and difficult to calculate due to the nonlinearities arising from the non-abelian character of the gauge fields.
Inviscid to turbulent transition of trailing vortices
NASA Technical Reports Server (NTRS)
Iversen, J. D.
1974-01-01
The characteristics of the plateau region in the vortex system which trails from a lifting wing are discussed. The decay of the vortex due to viscous or turbulent shear is very slow in the plateau so that the maximum tangential speed in the vortices remains nearly constant for some distance downstream of roll-up and then begins to decrease, becoming inversely proportional to the square root of the distance downstream. Mathematical models are developed to analyze the structure of the plateau area. Solutions are obtained for both constant and variable eddy viscosity models.
Nonlinear Generation of Vorticity by Surface Waves.
Filatov, S V; Parfenyev, V M; Vergeles, S S; Brazhnikov, M Yu; Levchenko, A A; Lebedev, V V
2016-02-01
We demonstrate that waves excited on a fluid surface produce local surface rotation owing to hydrodynamic nonlinearity. We examine theoretically the effect and obtain an explicit formula for the vertical vorticity in terms of the surface elevation. Our theoretical predictions are confirmed by measurements of surface motion in a cell with water where surface waves are excited by vertical and harmonic shaking the cell. The experimental data are in good agreement with the theoretical predictions. We discuss physical consequences of the effect. PMID:26894714
On the dynamical influence of ocean eddy potential vorticity fluxes
NASA Astrophysics Data System (ADS)
Maddison, J. R.; Marshall, D. P.; Shipton, J.
2015-08-01
The impact of eddy potential vorticity fluxes on the dynamical evolution of the flow is obscured by the presence of large and dynamically-inert rotational fluxes. However, the decomposition of eddy potential vorticity fluxes into rotational and divergent components is non-unique in a bounded domain and requires the imposition of an additional boundary condition. Here it is proposed to invoke a one-to-one correspondence between divergent eddy potential vorticity fluxes and non-divergent eddy momentum tendencies in the quasi-geostrophic residual-mean equations in order to select a unique divergent eddy potential vorticity flux. The divergent eddy potential vorticity flux satisfies a zero tangential component boundary condition. In a simply connected domain, the resulting divergent eddy potential vorticity flux satisfies a powerful optimality condition: it is the horizontally oriented divergent flux with minimum L2 norm. Hence there is a well-defined sense in which this approach removes as much of the dynamically inactive eddy potential vorticity flux as possible, and extracts an underlying dynamically active divergent eddy potential vorticity flux. It is shown that this approach leads to a divergent eddy potential vorticity flux which has an intuitive physical interpretation, via a direct relationship to the resulting forcing of the mean circulation.
Characteristics of internal vortical structures in a merged turbulent spot†
NASA Astrophysics Data System (ADS)
Makita, Hideharu; Nishizawa, Akira
2001-07-01
Interaction phenomena between two turbulent spots were investigated in a zero pressure-gradient laminar boundary layer. Two types of hotwire rakes, a 16-channel I- and a 30-channel X-probe gave clear instantaneous vortical motion inside the spots, showing that the single spot was an aggregation of many small-scale hairpin vortices accompanied by upwashes and downwashes around their legs. The legs, a pair of counter-rotating longitudinal vortices, were identified by the existence of streaky velocity-defect and -excess regions at the bottom of the spot. As the spot grew downstream, the number of longitudinal vortices increased, though its wingtips were always accompanied by upwashes. When two spots were produced in parallel and merged with each other, the upwash of the low-speed fluid was strongly enhanced in their merged part through the mutual interaction between the longitudinal vortices at their inside wingtips. Resultant unstable inflectional velocity profile gave birth to several spanwise vortices around the top of the merged part. These intensified spanwise vortices conformed the heads of horseshoe vortices and grew larger than those around the head of non-interacting isolated spots. Such strengthened horseshoe vortices possibly maintain their geometric identity to the turbulent boundary layer further downstream and initiate the turbulent bulges in it.
Dynamics of vortices and drift waves: a point vortex model
NASA Astrophysics Data System (ADS)
Leoncini, Xavier; Verga, Alberto
2013-03-01
The complex interactions of localized vortices with waves are investigated using a model of point vortices in the presence of a transverse or longitudinal wave. This simple model shows a rich dynamical behavior including oscillations of a dipole, splitting and merging of two like-circulation vortices, and chaos. The analytical and numerical results of this model have been found to predict under certain conditions, the behavior of more complex systems, such as the vortices of the Charney-Hasegawa-Mima equation, where the presence of waves strongly affects the evolution of large coherent structures.
Drift waves and vortices: a dynamical point vortex model
NASA Astrophysics Data System (ADS)
Leoncini, Xavier; Verga, Alberto
2013-10-01
Interactions of localized vortices with drift waves are investigated using a model of point vortices in the presence of a transverse or longitudinal wave. This simple model shows a rich dynamical behavior including oscillations of a dipole, splitting and merging of two like-circulation vortices, and chaos. The analytical and numerical results of this model have been found to predict under certain conditions, the behavior of more complex systems, such as the vortices of the Charney-Hasegawa-Mima equation, where the presence of waves strongly affects the evolution of large coherent structures.
On the stability of shear-Alfven vortices
Jovanovic, D.; Horton, W.
1993-08-01
Linear stability of shear-Alfven vortices is studied analytically using the Lyapunov method. Instability is demonstrated for vortices belonging to the drift mode, which is a generalization of the standard Hasegawa-Mima vortex to the case of large parallel phase velocities. In the case of the convective-cell mode, short perpendicular-wavelength perturbations are stable for a broad class of vortices. Eventually, instability of convective-cell vortices may occur on the perpendicular scale comparable with the vortex size, but it is followed by a simultaneous excitation of coherent structures with better localization than the original vortex.
On relation between scalar interfaces and vorticity in inviscid flows
NASA Astrophysics Data System (ADS)
Ramesh, O. N.; Patwardhan, Saurabh
2013-11-01
A great variety of applications like pollutant mixing in the atmosphere, mixing of reactants in combustion highlight the importance of passive scalar dynamics in fluid flows. The other dynamically important variable in the study of fluid flow is the vorticity. Vorticity though, unlike a passive scalar, does affect the fluid motion. The dynamics of scalar (linear) and vorticity (non-linear) are governed by the equations which inherently have different characteristics. This paper addresses the question of the faithfulness of representation of vorticity by scalar marker and the motivation for this comes from the experiment of Head and Bandyopadhyay (1981) which showed the existence of coherent vortices by using smoke flow visualization in a turbulent boundary layer. We will show analytically in regions where the molecular diffusion effects are negligible, the vorticity and scalar gradients are orthogonal to each other. The iso- surface of scalar follows the vorticity in an inviscid situation. Also, we will demonstrate that in the case of unsteady burgers vortex and vortex shedding behind a finite circular cylinder, the scalar gradient is orthogonal to vorticity and inner product of vorticity and scalar gradients is zero in regions away from the wall.
Observations of Electron Vorticity in the Inner Plasma Sheet
NASA Technical Reports Server (NTRS)
Gurgiolo, C.; Goldstein, M. L.; Vinas, A. F.; Matthaeus, W. H.; Fazakerley, A. N.
2011-01-01
From a limited number of observations it appears that vorticity is a common feature in the inner plasma sheet. With the four Cluster spacecraft and the four PEACE instruments positioned in a tetrahedral configuration, for the first time it is possible to directly estimate the electron fluid vorticity in a space plasma. We show examples of electron fluid vorticity from multiple plasma sheet crossings. These include three time periods when Cluster passed through a reconnection ion diffusion region. Enhancements in vorticity are seen in association with each crossing of the ion diffusion region.
Superconducting resonators with trapped vortices under direct injection of quasiparticles
NASA Astrophysics Data System (ADS)
Nsanzineza, Ibrahim; Patel, Umesh; Dodge, K. R.; McDermott, R. F.; Plourde, B. L. T.
Nonequilibrium quasiparticles and trapped magnetic flux vortices can significantly impact the performance of superconducting microwave resonant circuits and qubits at millikelvin temperatures. Quasiparticles result in excess loss, reducing resonator quality factors and qubit lifetimes. Vortices trapped near regions of large microwave currents also contribute excess loss. However, vortices located in current-free areas in the resonator or in the ground plane of a device can actually trap quasiparticles and lead to a reduction in the quasiparticle loss. We will describe experiments involving the controlled trapping of vortices in superconducting resonators with direct injection of quasiparticles using Normal metal-Insulator-Superconductor (NIS)-tunnel junctions.
Acoustical vortices on a Chip for 3D single particle manipulation and vorticity control
NASA Astrophysics Data System (ADS)
Riaud, Antoine; Thomas, Jean-Louis; Bou Matar, Olivier; Baudoin, Michael
Surface acoustic waves offer most of the basic functions required for on-chip actuation of fluids at small scales: efficient flow mixing, integrated pumping, particles separation, droplet displacement, atomization, division and fusion. Nevertheless some more advanced functions such as 3D particles manipulation and vorticity control require the introduction of some specific kind of waves called acoustic vortices. These helical waves propagate spinning around a phase singularity called the dark core. On the one hand, the beam angular momentum can be transferred to the fluid and create point-wise vorticity for confined mixing, and on the other the dark core can trap individual particles in an acoustic well for single object manipulation. In this presentation, I will show how acoustical vortices on-a-chip can be synthesized with a programmable electronics and an array of transducers. I will then highlight how some of their specificities can be used for acoustical tweezing and twisting. This work is supported by ANR Project No. ANR-12-BS09-0021-01 and ANR-12- BS09-0021-02, and Rgion Nord Pas de Calais.
Heterotic non-Abelian string of a finite length
NASA Astrophysics Data System (ADS)
Monin, S.; Shifman, M.; Yung, A.
2016-06-01
We consider non-Abelian strings in N =2 supersymmetric quantum chromodynamics (QCD) with the U (N ) gauge group and Nf=N quark flavors deformed by a mass term for the adjoint matter. This deformation breaks N =2 supersymmetry down to N =1 . Dynamics of orientational zero modes on the string world sheet are described then by C P (N -1 ) model with N =(0 ,2 ) supersymmetry. We study the string of a finite length L assuming compactification on a cylinder (periodic boundary conditions). The world-sheet theory is solved in the large-N approximation. At N =∞ we find a rich phase structure in the (L ,u ) plane where u is a deformation parameter. At large L and intermediate u we find a phase with broken Z2 N symmetry, N vacua and a mass gap. At large values of L and u still larger we have the Z2 N-symmetric phase with a single vacuum and massless fermions. In both phases N =(0 ,2 ) supersymmetry is spontaneously broken. We also observe a phase with would-be broken SU (N ) symmetry at small L (it is broken only for N =∞ ). In the latter phase the mass gap vanishes and the vacuum energy is zero in the leading 1 /N approximation. We expect that at large but finite N corrections O (1 /N ) will break N =(0 ,2 ) supersymmetry. Simultaneously, the phase transitions will become rapid crossovers. Finally we discuss how the observed rich phase structure matches the N =(2 ,2 ) limit in which the world-sheet theory has a single phase with the mass gap independent of L .
Neutral Supersymmetric Higgs Boson Searches
Robinson, Stephen Luke
2008-07-01
In some Supersymmetric extensions of the Standard Model, including the Minimal Supersymmetric Standard Model (MSSM), the coupling of Higgs bosons to b-quarks is enhanced. This enhancement makes the associated production of the Higgs with b-quarks an interesting search channel for the Higgs and Supersymmetry at D0. The identification of b-quarks, both online and offline, is essential to this search effort. This thesis describes the author's involvement in the development of both types of b-tagging and in the application of these techniques to the MSSM Higgs search. Work was carried out on the Level-3 trigger b-tagging algorithms. The impact parameter (IP) b-tagger was retuned and the effects of increased instantaneous luminosity on the tagger were studied. An extension of the IP-tagger to use the z-tracking information was developed. A new b-tagger using secondary vertices was developed and commissioned. A tool was developed to allow the use of large multi-run samples for trigger studies involving b-quarks. Offline, a neural network (NN) b-tagger was trained combining the existing offline lifetime based b-tagging tools. The efficiency and fake rate of the NN b-tagger were measured in data and MC. This b-tagger was internally reviewed and certified by the Collaboration and now provides the official b-tagging for all analyses using the Run IIa dataset at D0. A search was performed for neutral MSSM Higgs bosons decaying to a b{bar b} pair and produced in association with one or more b-quarks. Limits are set on the cross-section times the branching ratio for such a process. The limits were interpreted in various MSSM scenarios. This analysis uses the NN b-tagger and was the first to use this tool. The analysis also relies on triggers using the Level-3 IP b-tagging tool described previously. A likelihood discriminant was used to improve the analysis and a neural network was developed to cross-check this technique. The result of the analysis has been submitted to PRL and
(SUSY) Higgs Search at the LHC
Muehlleitner, M. Margarete
2008-11-23
The discovery of the Standard Model (SM) or supersymmetric (SUSY) Higgs bosons belongs to the main endeavors of the Large Hadron Collider (LHC). In this article the status of the signal and background calculations for Higgs boson production at the LHC is reviewed.
Higgs Boson Mass, Neutrino Oscillations and Inflation
Shafi, Qaisar
2008-11-23
Finding the Standard Model scalar (Higgs) boson is arguably the single most important mission of the LHC. I review predictions for the Higgs boson mass based on stability and perturbativity arguments, taking into account neutrino oscillations. Primordial inflation based on the Coleman-Weinberg potential is briefly discussed.
Bounding the Higgs boson width through interferometry.
Dixon, Lance J; Li, Ye
2013-09-13
We study the change in the diphoton-invariant-mass distribution for Higgs boson decays to two photons, due to interference between the Higgs resonance in gluon fusion and the continuum background amplitude for gg→γγ. Previously, the apparent Higgs mass was found to shift by around 100 MeV in the standard model in the leading-order approximation, which may potentially be experimentally observable. We compute the next-to-leading-order QCD corrections to the apparent mass shift, which reduce it by about 40%. The apparent mass shift may provide a way to measure, or at least bound, the Higgs boson width at the Large Hadron Collider through "interferometry." We investigate how the shift depends on the Higgs width, in a model that maintains constant Higgs boson signal yields. At Higgs widths above 30 MeV, the mass shift is over 200 MeV and increases with the square root of the width. The apparent mass shift could be measured by comparing with the ZZ* channel, where the shift is much smaller. It might be possible to measure the shift more accurately by exploiting its strong dependence on the Higgs transverse momentum. PMID:24074073
Collider Tests of the Little Higgs Model
Burdman, Gustavo; Perelstein, Maxim; Pierce, Aaron
2002-12-16
The little Higgs model provides an alternative to traditional candidates for new physics at the TeV scale. The new heavy gauge bosons predicted by this model should be observable at the Large Hadron Collider (LHC). We discuss how the LHC experiments could test the little Higgs model by studying the production and decay of these particles.
Higgs boson masses in supersymmetric models
Berger, M.S.
1991-04-01
Imposing supersymmetry on a Higgs potential constrains the parameters that define the potential. In supersymmetric extensions to the stranded model containing only Higgs SU(2){sub L} doublets there exist Higgs boson mass sum rules and bounds on the Higgs masses at tree level. The prescription for renormalizing these sum rules is derived. An explicit calculation is performed in the minimal supersymmetric extension to the standard model (MSSM). In this model at tree level the mass sum rule is M{sub H}{sup 2} + M{sub h}{sup 2} = M{sub A}{sup 2} + M{sub Z}{sup 2}. The results indicate that large corrections to the sum rules may arise from heavy matter fields, e.g. a heavy top quark. Squarks significantly heavier than their fermionic partners contribute large contributions when mixing occurs in the squark sector. These large corrections result from squark-Higgs couplings that become large in this limit. Contributions to individual Higgs boson masses that are quadratic in the squark masses cancel in the sum rule. Thus the naturalness constraint on Higgs boson masses is hidden in the combination of Higgs boson masses that comprise the sum rule. 39 refs., 13 figs.
NASA Astrophysics Data System (ADS)
Gu, Mingyao; Feltham, Graham; Ekmekci, Alis
2014-11-01
When oncoming streams of weak vorticity aligned with the axle axis of a two-wheel landing gear impinge near the forward stagnation point of the wheels, a mechanism for vorticity collection, growth, amplification into discrete large-scale vortices, and shedding was formerly shown to exist. In the current study, the impinging vorticity streams are perpendicular to the axle axis, i.e. in a vertical orientation as opposed to the horizontal orientation before. Experiments are conducted in a recirculating water channel using hydrogen bubble visualization and particle image velocimetry at a Reynolds number of 32,500 (based on the wheel diameter). As with the horizontal orientation, vorticity collection and amplification are observed, but the large-scale vortices thus formed are stretched around the wheel circumference in contrast to being stretched around the wheel sides, as observed for the horizontal orientation. This flow behavior varies with the impingement location of the vorticity streams across the wheel width. Maximum vorticity amplification occurs at a critical impingement location and drastically alters the flow separation along the wheel circumference. In addition, the instantaneous vortical structures are identified and tracked using a Galilean-invariant criterion.
Sun, Fadi; Yu, Xiao-Lu; Ye, Jinwu; Fan, Heng; Liu, Wu-Ming
2013-01-01
The method of synthetic gauge potentials opens up a new avenue for our understanding and discovering novel quantum states of matter. We investigate the topological quantum phase transition of Fermi gases trapped in a honeycomb lattice in the presence of a synthetic non-Abelian gauge potential. We develop a systematic fermionic effective field theory to describe a topological quantum phase transition tuned by the non-Abelian gauge potential and explore its various important experimental consequences. Numerical calculations on lattice scales are performed to compare with the results achieved by the fermionic effective field theory. Several possible experimental detection methods of topological quantum phase transition are proposed. In contrast to condensed matter experiments where only gauge invariant quantities can be measured, both gauge invariant and non-gauge invariant quantities can be measured by experimentally generating various non-Abelian gauges corresponding to the same set of Wilson loops. PMID:23846153
Controlling and probing non-abelian emergent gauge potentials in spinor Bose-Fermi mixtures
Phuc, Nguyen Thanh; Tatara, Gen; Kawaguchi, Yuki; Ueda, Masahito
2015-01-01
Gauge fields, typified by the electromagnetic field, often appear as emergent phenomena due to geometrical properties of a curved Hilbert subspace, and provide a key mechanism for understanding such exotic phenomena as the anomalous and topological Hall effects. Non-abelian gauge potentials serve as a source of non-singular magnetic monopoles. Here we show that unlike conventional solid materials, the non-abelianness of emergent gauge potentials in spinor Bose-Fermi atomic mixtures can be continuously varied by changing the relative particle-number densities of bosons and fermions. The non-abelian feature is captured by an explicit dependence of the measurable spin current density of fermions in the mixture on the variable coupling constant. Spinor mixtures also provide us with a method to coherently and spontaneously generate a pure spin current without relying on the spin Hall effect. Such a spin current is expected to have potential applications in the new generation of atomtronic devices. PMID:26330292
Perfect Abelian dominance of confinement in quark-antiquark potential in SU(3) lattice QCD
NASA Astrophysics Data System (ADS)
Suganuma, Hideo; Sakumichi, Naoyuki
2016-01-01
In the context of the dual superconductor picture for the confinement mechanism, we study maximally Abelian (MA) projection of quark confinement in SU(3) quenched lattice QCD with 324 at β=6.4 (i.e., a ≃ 0.058 fm). We investigate the static quark-antiquark potential V(r), its Abelian part VAbel(r) and its off-diagonal part Voff(r), respectively, from the on-axis lattice data. As a remarkable fact, we find almost perfect Abelian dominance for quark confinement, i.e., σAbel ≃ σ for the string tension, on the fine and large-volume lattice. We find also a nontrivial summation relation of V (r) ≃ VAbel(r)+Voff(r).
Monopoles and fractional vortices in chiral superconductors
Volovik, G. E.
2000-01-01
I discuss two exotic objects that must be experimentally identified in chiral superfluids and superconductors. These are (i) the vortex with a fractional quantum number (N = 1/2 in chiral superfluids, and N = 1/2 and N = 1/4 in chiral superconductors), which plays the part of the Alice string in relativistic theories and (ii) the hedgehog in the ^l field, which is the counterpart of the Dirac magnetic monopole. These objects of different dimensions are topologically connected. They form the combined object that is called a nexus in relativistic theories. In chiral superconductors, the nexus has magnetic charge emanating radially from the hedgehog, whereas the half-quantum vortices play the part of the Dirac string. Each half-quantum vortex supplies the fractional magnetic flux to the hedgehog, representing 1/4 of the “conventional” Dirac string. I discuss the topological interaction of the superconductor's nexus with the ‘t Hooft–Polyakov magnetic monopole, which can exist in Grand Unified Theories. The monopole and the hedgehog with the same magnetic charge are topologically confined by a piece of the Abrikosov vortex. Such confinement makes the nexus a natural trap for the magnetic monopole. Other properties of half-quantum vortices and monopoles are discussed as well, including fermion zero modes. PMID:10716980
The effect of entrainment on starting vortices
NASA Astrophysics Data System (ADS)
Rosi, Giuseppe; Rival, David
2015-11-01
Recent work shows that vortex detachment behind accelerating plates coincides with when streamlines enclosing the starting vortex (SV) form a full saddle. In the case of a linearly accelerating plate, it can be shown that vorticity-containing mass, and thus the SV's development scale with only dimensionless towed distance, while the SV's circulation scales with the acceleration rate. This results in shear-layer instabilities whose structure is Reynold-number independent, but whose strength scale with Reynolds number. It is hypothesized that the increased strength of the instabilities promotes entrainment, which causes the formation of the full saddle and thereby detachment to occur at an earlier dimensionless towed distance. To test this hypothesis, a circular plate is linearly accelerated from rest to pinch-off with chord-based Reynolds numbers of 103, 104, and 105 at the midpoint of the motion. Planar PIV data is acquired, from which FTLE and enstrophy fields are calculated. Vortex detachment is identified from the dynamics of the FTLE saddles, while the enstrophy fields are used to calculate both the vorticity-containing mass entering from the shear layer and the mass entrained from the quiescent surroundings.
Tomographic PIV Study of Hairpin Vortices
NASA Astrophysics Data System (ADS)
Sabatino, Daniel; Rossmann, Tobias
2014-11-01
Tomographic PIV is used in a free surface water channel to quantify the flow behavior of hairpin vortices that are artificially generated in a laminar boundary layer. Direct injection from a 32:1 aspect ratio slot at low blowing ratios (0 . 1 < BR < 0 . 2) is used to generate an isolated hairpin vortex in a thick laminar boundary layer (485 < Reδ* < 600). Due to the large dynamic range of length and velocity scales (the resulting vortices have advection velocities 5X greater than their tangential velocities), a tailored optical arrangement and specialized post processing techniques are required to fully capture the small-scale behavior and long-time development of the flow field. Hairpin generation and evolution are presented using the λ2 criterion derived from the instantaneous, three-dimensional velocity field. The insight provided by the tomographic data is also compared to the conclusions drawn from 2D PIV and passive scalar visualizations. Finally, the three-dimensional behavior of the measured velocity field is correlated with that of a simultaneously imaged, passive scalar dye that marks the boundary of the injected fluid, allowing the examination of the entrainment behavior of the hairpin. Supported by the National Science Foundation under Grant CBET-1040236.
Large eddy simulation of longitudinal stationary vortices
NASA Astrophysics Data System (ADS)
Sreedhar, Madhu; Ragab, Saad
1994-07-01
The response of longitudinal stationary vortices when subjected to random perturbations is investigated using temporal large-eddy simulation. Simulations are obtained for high Reynolds numbers and at a low subsonic Mach number. The subgrid-scale stress tensor is modeled using the dynamic eddy-viscosity model. The generation of large-scale structures due to centrifugal instability and their subsequent breakdown to turbulence is studied. The following events are observed. Initially, ring-shaped structures appear around the vortex core. These structures are counter-rotating vortices similar to the donut-shaped structures observed in a Taylor-Couette flow between rotating cylinders. These structures subsequently interact with the vortex core resulting in a rapid decay of the vortex. The turbulent kinetic energy increases rapidly until saturation, and then a period of slow decay prevails. During the period of maximum turbulent kinetic energy, the normalized mean circulation profile exhibits a logarithmic region, in agreement with the universal inner profile of Hoffman and Joubert [J. Fluid Mech. 16, 395 (1963)].
Reconnection of vorticity lines and magnetic lines
NASA Technical Reports Server (NTRS)
Greene, John M.
1993-01-01
Magnetic field and fluid vorticity share many features. First, as divergence-free vector fields they are conveniently visualized in terms of their field lines, curves that are everywhere tangent to the field. The lines indicate direction and their density indicates field strength. The question arises of the extent to which the evolution of the fields can be treated in terms of the evolution of their field lines. Newcomb (1958) derived the general conditions on the evolution of vector fields that permit the identification of field lines from one instant to the next. The equations of evolution of the vorticity field and the magnetic field fall within Newcomb's analysis. The dynamics of the flows differ between these two systems, so that geometrically similar phenomena happen in different ways in the two systems. In this paper the geometrical similarities are emphasized. Reconnection will be defined here as evolution in which it is not possible to preserve the global identification of some field lines. There is a close relation between reconnection and the topology of the vector field lines. Nontrivial topology occurs where the field has null points or there are field lines that are closed loops.
Vortices and flux tubes: The crossover
NASA Astrophysics Data System (ADS)
Bracco, A.; Spiegel, E. A.
2012-12-01
The sun has magnetic flux tubes that cause sunspots by locally inhibiting convection near its surface. Jupiter has vortices that make the great red spot and other such blemishes. Why are there no similar vortices on the sun? How is the difference in the two kinds of system controlled by the magnetic Prandtl number? What happens at the crossover between the two behaviors? The transition between velocity and magnetically dominated regimes is the driving question of this work. It should occur somewhere in the enormous range in Prandtl number between the sun and planets like Jupiter. Objects that lie in between these vastly different extremes are Brown Dwarfs that have such low mass that they do not burn hydrogen in their cores. These objects are now being actively observed though there is as yet no direct evidence bearing on the present calculations. Other possibly interesting conditions may arise in certain disks around newborn stars where planetary systems are thought to be forming. These may be cool enough to place them in an interesting parameter range for the competition we describe. Using 2D calculations, we seek a quantitative measure of the relative importance of the two vector fields seen in the calculations, statistical or spectral, topological or structural.
Abrikosov Gluon Vortices in Color Superconductors
NASA Astrophysics Data System (ADS)
Ferrer, Efrain J.
2011-09-01
In this talk I will discuss how the in-medium magnetic field can influence the gluon dynamics in a three-flavor color superconductor. It will be shown how at field strengths comparable to the charged gluon Meissner mass a new phase can be realized, giving rise to Abrikosov's vortices of charged gluons. In that phase, the inhomogeneous gluon condensate anti-screens the magnetic field due to the anomalous magnetic moment of these spin-1 particles. This paramagnetic effect can be of interest for astrophysics, since due to the gluon vortex antiscreening mechanism, compact stars with color superconducting cores could have larger magnetic fields than neutron stars made up entirely of nuclear matter. I will also discuss a second gluon condensation phenomenon connected to the Meissner instability attained at moderate densities by two-flavor color superconductors. In this situation, an inhomogeneous condensate of charged gluons emerges to remove the chromomagnetic instability created by the pairing mismatch, and as a consequence, the charged gluonic currents induce a magnetic field. Finally, I will point out a possible relation between glitches in neutron stars and the existence of the gluon vortices.
Close relative equilibria of identical point vortices
NASA Astrophysics Data System (ADS)
Dirksen, Tobias; Aref, Hassan
2011-11-01
Via numerical solution of the classical problem of relative equilibria for identical point vortices on the unbounded plane we have found configurations that are very close to the analytically known, centered, symmetrically arranged, nested equilateral triangles. Numerical solutions of this kind were found for 3 n + 1 vortices, where n = 2 , 3 , ... , 30 . A sufficient, although apparently not necessary, condition for this phenomenon of close solutions is that the ``core'' of the configuration is marginally stable, as occurs for a central vortex surrounded by an equilateral triangle. The open, regular heptagon also has this property, and new relative equilibria close to the nested, symmetrically arranged, regular heptagons have been found. The centered regular nonagon is also marginally stable. Again, a new family of close relative equilibria has been found. The closest relative equilibrium pairs occur, however, for symmetrically nested equilateral triangles. The numerical evidence is surveyed and related recent work mentioned. A Letter in Physics of Fluids 23 (2011) 051706 is available. Supported in part by the Danish National Research Foundation through a Niels Bohr visiting professorship.
Dynamics of Quantized Vortices Before Reconnection
NASA Astrophysics Data System (ADS)
Andryushchenko, V. A.; Kondaurova, L. P.; Nemirovskii, S. K.
2016-04-01
The main goal of this paper is to investigate numerically the dynamics of quantized vortex loops, just before the reconnection at finite temperature, when mutual friction essentially changes the evolution of lines. Modeling is performed on the base of vortex filament method using the full Biot-Savart equation. It was discovered that the initial position of vortices and the temperature strongly affect the dependence on time of the minimum distance δ (t) between tips of two vortex loops. In particular, in some cases, the shrinking and collapse of vortex loops due to mutual friction occur earlier than the reconnection, thereby canceling the latter. However, this relationship takes a universal square-root form δ ( t) =√{( κ/2π ) ( t_{*}-t) } at distances smaller than the distances, satisfying the Schwarz reconnection criterion, when the nonlocal contribution to the Biot-Savart equation becomes about equal to the local contribution. In the "universal" stage, the nearest parts of vortices form a pyramid-like structure with angles which neither depend on the initial configuration nor on temperature.
Four vortices on doubly periodic paths
NASA Astrophysics Data System (ADS)
Rott, Nicholas
1994-02-01
Plane vortex configurations in ideal flow are considered for which the total ``mass'' of the vortex strengths, their ``moments,'' and their ``polar moments of inertia'' all vanish. These properties are conserved for all times. The simplest nontrivial realization of such a configuration requires four vortices. For this case, which belongs to the more extended family of four-vortex problems that are known to be integrable [Phys. Fluids 31, 2796 (1989); Phys. Fluids A 2, 1477 (1990)], some simple closed-form results are given. The analysis shows that the paths are periodic in a ``configuration plane'' moving with the vortices as well as in the absolute fluid plane. A ``winding number'' is determined from the analysis, which gives the ratio of the two periods. Patterns of the vortex paths are determined by a program based on the step-by-step integration of the equations of motion, which is—beyond a certain level of the analysis—still the more practical method of solution. Results showing the typical behavior of the motion paths for different winding numbers are presented.
Vortices in superconducting MoGe pentagon
NASA Astrophysics Data System (ADS)
Ishida, Takekazu; Thanh Huy, Ho; Kato, Masaru; Hayashhi, Masahiko
2013-03-01
Vortices in bulk prefer to form a triangular lattice while a mesoscopic superconductor with a size comparable to coherence length ξ or the magnetic penetration depth λ is quite different so as to create particular configuration of vortices. The behavior of such structures in an external magnetic field is strongly influenced by the boundary conditions. Vortex states in superconducting disk, triangle and square pattern have been extensively studied both theoretically and experimentally [B. J. Baelus et al., Phys. Rev. B 69, 064506 (2004)]. We present vortex structures in MoGe pentagon disks imaged by means of a scanning quantum interference device (SQUID) microscopy [Ho Thanh Huy et al., Physica C, in press; DOI 10.1016/j.physc.2012.03.037.] Systematic measurements allow us to reveal how vortex arrangement evolves with the applied magnetic field. Moreover, we found that shell filling rule is subjected to change when a pinning center is introduced. Numerical calculations of vortex structure in pentagon disks on the basis of the nonlinear Ginzburg-Landau theory reveal that there are good agreement between experimental data and theoretical calculations.
Optimal Free-Stream Vortical Disturbances
NASA Astrophysics Data System (ADS)
Hack, M. J. Philipp
2015-11-01
In boundary layers exposed to moderate levels of free-stream disturbances, natural transition via the exponential amplification of Tollmien-Schlichting waves is bypassed by a more rapid breakdown process. The external disturbances interact with the mean shear and induce the growth of highly energetic streaks, which cause transition to turbulence by virtue of the growth of inviscid secondary instabilities. The relationship between external vortices and boundary-layer perturbations is, however, not entirely understood. The present study provides a rigorous link between the dynamics in the free-stream and inside the boundary layer by computing the optimal free-stream vortical disturbances, i.e. the external disturbances which maximize the energy content of the resulting boundary-layer perturbations. The mathematical framework is based on a semi-norm formulation of the adjoint linearized compressible Navier-Stokes equations in curvilinear coordinates and enables the global analysis of disturbance sensitivity as well as the computation of optimal disturbances in flows with variable density and miscellaneous geometries.
Electric-magnetic dualities in non-abelian and non-commutative gauge theories
NASA Astrophysics Data System (ADS)
Ho, Jun-Kai; Ma, Chen-Te
2016-08-01
Electric-magnetic dualities are equivalence between strong and weak coupling constants. A standard example is the exchange of electric and magnetic fields in an abelian gauge theory. We show three methods to perform electric-magnetic dualities in the case of the non-commutative U (1) gauge theory. The first method is to use covariant field strengths to be the electric and magnetic fields. We find an invariant form of an equation of motion after performing the electric-magnetic duality. The second method is to use the Seiberg-Witten map to rewrite the non-commutative U (1) gauge theory in terms of abelian field strength. The third method is to use the large Neveu Schwarz-Neveu Schwarz (NS-NS) background limit (non-commutativity parameter only has one degree of freedom) to consider the non-commutative U (1) gauge theory or D3-brane. In this limit, we introduce or dualize a new one-form gauge potential to get a D3-brane in a large Ramond-Ramond (R-R) background via field redefinition. We also use perturbation to study the equivalence between two D3-brane theories. Comparison of these methods in the non-commutative U (1) gauge theory gives different physical implications. The comparison reflects the differences between the non-abelian and non-commutative gauge theories in the electric-magnetic dualities. For a complete study, we also extend our studies to the simplest abelian and non-abelian p-form gauge theories, and a non-commutative theory with the non-abelian structure.
The Minimal Supersymmetric Fat Higgs Model
Harnik, Roni; Kribs, Graham D.; Larson, Daniel T.; Murayama, Hitoshi
2003-11-26
We present a calculable supersymmetric theory of a composite"fat'" Higgs boson. Electroweak symmetry is broken dynamically through a new gauge interaction that becomes strong at an intermediate scale. The Higgs mass can easily be 200-450 GeV along with the superpartner masses, solving the supersymmetric little hierarchy problem. We explicitly verify that the model is consistent with precision electroweak data without fine-tuning. Gauge coupling unification can be maintained despite the inherently strong dynamics involved in electroweak symmetry breaking. Supersymmetrizing the Standard Model therefore does not imply a light Higgs mass, contrary to the lore in the literature. The Higgs sector of the minimal Fat Higgs model has a mass spectrum that is distinctly different from the Minimal Supersymmetric Standard Model.
Gauge-Higgs EW and grand unification
NASA Astrophysics Data System (ADS)
Hosotani, Yutaka
2016-07-01
Four-dimensional Higgs field is identified with the extra-dimensional component of gauge potentials in the gauge-Higgs unification scenario. SO(5) × U(1) gauge-Higgs EW unification in the Randall-Sundrum warped space is successful at low energies. The Higgs field appears as an Aharonov-Bohm phase 𝜃H in the fifth dimension. Its mass is generated at the quantum level and is finite. The model yields almost the same phenomenology as the standard model for 𝜃H < 0.1, and predicts Z‧ bosons around 6-10 TeV with very broad widths. The scenario is generalized to SO(11) gauge-Higgs grand unification. Fermions are introduced in the spinor and vector representations of SO(11). Proton decay is naturally forbidden.
Minimal Composite Higgs Models at the LHC
Carena, Marcela; Da Rold, Leandro; Pontón, Eduardo
2014-06-26
We consider composite Higgs models where the Higgs is a pseudo-Nambu Goldstone boson arising from the spontaneous breaking of an approximate global symmetry by some underlying strong dynamics. We focus on the SO(5) → SO(4) symmetry breaking pattern, assuming the “partial compositeness” paradigm. We study the consequences on Higgs physics of the fermionic representations produced by the strong dynamics, that mix with the Standard Model (SM) degrees of freedom. We consider models based on the lowest-dimensional representations of SO(5) that allow for the custodial protection of the Z b ¯ b coupling, i.e. the 5, 10 and 14. We find a generic suppression of the gluon fusion process, while the Higgs branching fractions can be enhanced or suppressed compared to the SM. Interestingly, a precise measurement of the Higgs boson couplings can distinguish between different realizations in the fermionic sector, thus providing crucial information about the nature of the UV dynamics.
Higgs coupling measurements at the LHC
NASA Astrophysics Data System (ADS)
Englert, Christoph; Kogler, Roman; Schulz, Holger; Spannowsky, Michael
2016-07-01
Due to the absence of tantalising hints for new physics during the LHC's Run 1, the extension of the Higgs sector by dimension-six operators will provide the new phenomenological standard for searches of non-resonant extensions of the Standard Model. Using all dominant and subdominant Higgs production mechanisms at the LHC, we compute the constraints on Higgs physics-relevant dimension-six operators in a global and correlated fit. We show in how far these constraints can be improved by new Higgs channels becoming accessible at higher energy and luminosity, both through inclusive cross sections as well as through highly sensitive differential distributions. This allows us to discuss the sensitivity to new effects in the Higgs sector that can be reached at the LHC if direct hints for physics beyond the SM remain elusive. We discuss the impact of these constraints on well-motivated BSM scenarios.
Resonant mono Higgs at the LHC
NASA Astrophysics Data System (ADS)
Basso, Lorenzo
2016-04-01
In recent years, the production of a SM particle with large missing transverse momentum, dubbed mono-X searches, have gained increasing attention. After the discovery of the Higgs boson in 2012, the run-II of the LHC will now scrutinise its properties, looking for BSM physics. In particular, one could search for mono-Higgs signals, that are typically studied in models addressing dark matter. However, this signal can appear also in models addressing the neutrino masses, if additional heavier neutrinos with masses at the electroweak scale are present. The latter will couple to the SM neutrinos and the Higgs boson, yielding a type of mono-Higgs signal not considered for dark matter: the resonant production of a Higgs boson and missing energy. In this paper, we address the LHC exclusion power of the latter with dedicated detector simulations, and reinterpret it in a benchmark scenario for neutrino mass generation.
Fermiophobia in a Higgs triplet model
Akeroyd, A. G.; Diaz, Marco A.; Romero Maltrana, D.; Rivera, Maximiliano A.
2011-05-01
A fermiophobic Higgs boson can arise in models with an extended Higgs sector, such as models with scalars in an isospin triplet representation. In a specific model with a scalar triplet and spontaneous violation of lepton number induced by a scalar singlet field, we show that fermiophobia is not a fine-tuned situation, unlike in two higgs doublet models. We study distinctive signals of fermiophobia which can be probed at the LHC. For the case of a small Higgs mass, a characteristic signal would be a moderate B(H{yields}{gamma}{gamma}) accompanied by a large B(H{yields}JJ) (where J is a Majoron), the latter being an invisible decay. For the case of a large Higgs mass there is the possibility of dominant H{yields}ZZ, WW and suppressed H{yields}JJ decay modes. In this situation, B(H{yields}ZZ) is larger than B(H{yields}WW), which differs from the SM prediction.
The problem with false vacuum Higgs inflation
Fairbairn, Malcolm; Grothaus, Philipp; Hogan, Robert E-mail: philipp.grothaus@kcl.ac.uk
2014-06-01
We investigate the possibility of using the only known fundamental scalar, the Higgs, as an inflaton with minimal coupling to gravity. The peculiar appearance of a plateau or a false vacuum in the renormalised effective scalar potential suggests that the Higgs might drive inflation. For the case of a false vacuum we use an additional singlet scalar field, motivated by the strong CP problem, and its coupling to the Higgs to lift the barrier allowing for a graceful exit from inflation by mimicking hybrid inflation. We find that this scenario is incompatible with current measurements of the Higgs mass and the QCD coupling constant and conclude that the Higgs can only be the inflaton in more complicated scenarios.
Probing the non-minimal Higgs sector at the SSC
Gunion, J.F.; Haber, H.E.; Komamiya, S.; Yamamoto, H.; Barbaro-Galtieri, A.
1987-11-01
Non-minimal Higgs sectors occur in the Standard Model with more than one Higgs doublet, as well as in theories that go beyond the Standard Model. In this report, we discuss how Higgs search strategies must be altered, with respect to the Standard Model approaches, in order to probe the non-minimal Higgs sectors at the SSC.
NASA Astrophysics Data System (ADS)
Hassanzadeh, Pedram
Large coherent vortices are abundant in geophysical and astrophysical flows. They play significant roles in the Earth's oceans and atmosphere, the atmosphere of gas giants, such as Jupiter, and the protoplanetary disks around forming stars. These vortices are essentially three-dimensional (3D) and baroclinic, and their dynamics are strongly influenced by the rotation and density stratification of their environments. This work focuses on improving our understanding of the physics of 3D baroclinic vortices in rotating and continuously stratified flows using 3D spectral simulations of the Boussinesq equations, as well as simplified mathematical models. The first chapter discusses the big picture and summarizes the results of this work. In Chapter 2, we derive a relationship for the aspect ratio (i.e., vertical half-thickness over horizontal length scale) of steady and slowly-evolving baroclinic vortices in rotating stratified fluids. We show that the aspect ratio is a function of the Brunt-Vaisala frequencies within the vortex and outside the vortex, the Coriolis parameter, and the Rossby number of the vortex. This equation is basically the gradient-wind equation integrated over the vortex, and is significantly different from the previously proposed scaling laws that find the aspect ratio to be only a function of the properties of the background flow, and independent of the dynamics of the vortex. Our relation is valid for cyclones and anticyclones in either the cyclostrophic or geostrophic regimes; it works with vortices in Boussinesq fluids or ideal gases, and non-uniform background density gradient. The relation for the aspect ratio has many consequences for quasi-equilibrium vortices in rotating stratified flows. For example, cyclones must have interiors more stratified than the background flow (i.e., super-stratified), and weak anticyclones must have interiors less stratified than the background (i.e., sub-stratified). In addition, this equation is useful to
Cold Atoms in Non-Abelian Gauge Potentials: From the Hofstadter Moth to Lattice Gauge Theory
Osterloh, K.; Baig, M.; Santos, L.; Zoller, P.; Lewenstein, M.
2005-07-01
We demonstrate how to create artificial external non-Abelian gauge potentials acting on cold atoms in optical lattices. The method employs atoms with k internal states, and laser assisted state sensitive tunneling, described by unitary kxk matrices. The single-particle dynamics in the case of intense U(2) vector potentials lead to a generalized Hofstadter butterfly spectrum which shows a complex mothlike structure. We discuss the possibility to realize non-Abelian interferometry (Aharonov-Bohm effect) and to study many-body dynamics of ultracold matter in external lattice gauge fields.
Momentum subtraction scheme renormalization group functions in the maximal Abelian gauge
NASA Astrophysics Data System (ADS)
Bell, J. M.; Gracey, J. A.
2013-10-01
The one-loop 3-point vertex functions of QCD in the maximal Abelian gauge are evaluated at the fully symmetric point at one loop. As a consequence the theory is renormalized in the various momentum subtraction schemes, which are defined by the trivalent vertices, as well as in the MS¯ scheme. From these the two-loop renormalization group functions in the momentum schemes are derived using the one-loop conversion functions. In parallel we repeat the analysis for the Curci-Ferrari gauge, which corresponds to the maximal Abelian gauge in a specific limit. The relation between the Λ parameters in different schemes is also provided.
Non-Abelian geometric phase and long-range atomic forces
NASA Technical Reports Server (NTRS)
Zygelman, B.
1990-01-01
It is shown how gauge fields, or geometric phases, manifest as observable effects in both bound and free diatom systems. It is shown that, in addition to altering energy splittings in bound systems, geometric phases induce transitions in levels separated by a finite-energy gap. An example is given where the non-Abelian gauge field couples nondegenerate electronic levels in a diatom. This gauge-field coupling gives rise to an observable effect. It is shown that when the diatom is 'pulled apart', the non-Abelian geometric phase manifests as a long-range atomic force.
Enhancing Gauge Symmetries of Non-Abelian Supersymmetric Chern-Simons Model
NASA Astrophysics Data System (ADS)
Gharavi, Kh. Bahalke; Monemzadeh, M.; Nejad, S. Abarghouei
2016-07-01
In this article, we study gauge symmetries of the Non-Abelian Supersymmetric Chern-Simons model (SCS) of SU(2) group at (2+1)-dimensions in the framework of the formalism of constrained systems. Since, broken gauge symmetries in this physical system lead to the presence of nonphysical degrees of freedom, the Non-Abelian SCS model is strictly constrained to second-class constraints. Hence, by introducing some auxiliary fields and using finite order BFT method, we obtain a gauge symmetric model by converting second-class constraint to first-class ones. Ultimately, the partition function of the model is obtained in the extended phase space.
Necessity of an energy barrier for self-correction of Abelian quantum doubles
NASA Astrophysics Data System (ADS)
Kómár, Anna; Landon-Cardinal, Olivier; Temme, Kristan
2016-05-01
We rigorously establish an Arrhenius law for the mixing time of quantum doubles based on any Abelian group Zd. We have made the concept of the energy barrier therein mathematically well defined; it is related to the minimum energy cost the environment has to provide to the system in order to produce a generalized Pauli error, maximized for any generalized Pauli errors, not only logical operators. We evaluate this generalized energy barrier in Abelian quantum double models and find it to be a constant independent of system size. Thus, we rule out the possibility of entropic protection for this broad group of models.
Kauffman knot polynomials in classical abelian Chern-Simons field theory
Liu Xin
2010-12-15
Kauffman knot polynomial invariants are discovered in classical abelian Chern-Simons field theory. A topological invariant t{sup I(L)} is constructed for a link L, where I is the abelian Chern-Simons action and t a formal constant. For oriented knotted vortex lines, t{sup I} satisfies the skein relations of the Kauffman R-polynomial; for un-oriented knotted lines, t{sup I} satisfies the skein relations of the Kauffman bracket polynomial. As an example the bracket polynomials of trefoil knots are computed, and the Jones polynomial is constructed from the bracket polynomial.
Standard electroweak interactions and Higgs bosons
Cox, B.; Gilman, F.J.
1984-09-01
In the standard model, only one basic component remains to be found: the Higgs boson. The specifics of Higgs boson production and detection, with decay to t anti t and a particular t quark mass range in mind, have not been examined in detail. As such, the working group on Standard Electroweak Interactions and Higgs Bosons at this meeting decided to concentrate on Higgs boson production and detection at SSC energies in the particular case where the Higgs mass is in the range so as to make t anti t quark-antiquark pairs the dominant decay mode. The study of this case, that of the so-called intermediate mass Higgs, had already been launched in the Berkeley PSSC Workshop on Electroweak Symmetry Breaking, and was continued and extended here. The problems of t quark jet identification and detection efficiency and the manner of rejection of background (especially from b quark jets) with realistic detectors then occupied much of the attention of the group. The subject of making precise measurements of parameters in the standard model at SSC energies is briefly examined. Then we delve into the Higgs sector, with an introduction to the neutral Higgs of the standard model together with its production cross-sections in various processes and the corresponding potential backgrounds. A similar, though briefer, discussion for a charged Higgs boson (outside the Standard Model) follows. The heart of the work on identifying and reconstructing the t and then the Higgs boson in the face of backgrounds is discussed. The problems with semileptonic decays, low energy jet fragments, mass resolution, and b-t discrimination all come to the fore. We have tried to make a serious step here towards a realistic assessment of the problems entailed in pulling a signal out of the background, including a rough simulation of calorimeter-detector properties. 25 references.
Bulk stabilization, the extra-dimensional Higgs portal and missing energy in Higgs events
NASA Astrophysics Data System (ADS)
Diener, Ross; Burgess, C. P.
2013-05-01
To solve the hierarchy problem, extra-dimensional models must explain why the new dimensions stabilize to the right size, and the known mechanisms for doing so require bulk scalars that couple to the branes. Because of these couplings the energetics of dimensional stabilization competes with the energetics of the Higgs vacuum, with potentially observable effects. These effects are particularly strong for one or two extra dimensions because the bulk-Higgs couplings can then be super-renormalizable or dimensionless. Experimental reach for such extra-dimensional Higgs `portals' are stronger than for gravitational couplings because they are less suppressed at low-energies. We compute how Higgs-bulk coupling through such a portal with two extra dimensions back-reacts onto properties of the Higgs boson. When the KK mass is smaller than the Higgs mass, mixing with KK modes results in an invisible Higgs decay width, missing-energy signals at high-energy colliders, and new mechanisms of energy loss in stars and supernovae. Astrophysical bounds turn out to be complementary to collider measurements, with observable LHC signals allowed by existing constraints. We comment on the changes to the Higgs mass-coupling relationship caused by Higgs-bulk mixing, and how the resulting modifications to the running of Higgs couplings alter vacuum-stability and triviality bounds.
Towards a theory of stochastic vorticity-augmentation. [tornado model
NASA Technical Reports Server (NTRS)
Liu, V. C.
1977-01-01
A new hypothesis to account for the formation of tornadoes is presented. An elementary one-dimensional theory is formulated for vorticity transfer between an ambient sheared wind and a transverse penetrating jet. The theory points out the relevant quantities to be determined in describing the present stochastic mode of vorticity augmentation.
The vortices in the latticed model of the planar nematic
Khvechshenko, D.V.; Kogan, Y.I.; Nechaev, S.K.
1990-06-01
The vortices in the planar nematic are considered using the field-theoretical description in terms of the Rp{sup 2} {sigma}-model. In the strong-coupling expansion the vortices interactions are considered and the new type of phase transition is obtained in the mean-field approximation.
Separating Internal Waves and Vortical Structure in the Open Ocean
NASA Astrophysics Data System (ADS)
Lauffenburger, N. E.; Sanford, T. B.; Lien, R.
2012-12-01
Deviating from past oceanographic surveys, a new, powerful array of profiling floats has been deployed for three weeks in the Sargasso Sea to monitor the evolving sub-mesoscale field. Using 18-20 EM-APEX floats, profiling to 100 m depth simultaneously, velocity (U and V), temperature, salinity and microstructure measurements (χ) were made on horizontal scales between 100 m and 10 km. This strategy provided a 3-D snapshot of the physical properties every half hour, which significantly reduces temporal aliasing. Area-averaged relative vorticity, vortex stretching, non-linear twisting, horizontal divergence and Ertel's potential vorticity have been computed and projected onto isopycnal surfaces. Since vortical modes carry Ertel's potential vorticity (and internal waves do not), this is a useful step in understanding the energetic contribution of vortical motions to the background internal wave field on small scales. In addition, the temporal material conservation law of Ertel's potential vorticity will be tested for the first time by determining the advection of the floats' measurements relative to the motion of the water parcels and by computing the horizontal gradients of the potential vorticity signal. The three deployments provide data to analyze the interaction of inertial waves, vortical processes and barotropic tides in and out of active frontogenesis.
Vorticity amplification near the stagnation point of landing gear wheels
NASA Astrophysics Data System (ADS)
Feltham, G.; Ekmekci, A.
2014-04-01
The vicinity near the forward stagnation point of landing-gear wheels has been found to support a mechanism for oncoming streams of weak vorticity to collect, grow, and amplify into discrete large-scale vortical structures that then shed with a distinct periodicity. To the authors' knowledge, such a flow phenomenon has never been reported before for landing gear wheels, which are in essence finite (three-dimensional) cylinders. To gain further insight into this phenomenon, a detailed experimental study has been undertaken employing the hydrogen bubble visualization and Particle Image Velocimetry techniques. A very thin platinum wire, similar to those used in hydrogen bubble visualization applications, was placed upstream of the wheel model to produce two streams of weak vorticity (with opposite sign) that convected toward the model. As the vorticity streams enter the stagnation region of the wheels, significant flow deceleration and vorticity stretching act to collect, grow, and amplify the incoming vorticity streams into large-scale vortical structures. Experiments were performed at a fixed Reynolds number, with a value of 32 500 when defined based on the diameter of the wheel and a value of 21 based on the diameter of the vorticity-generating upstream wire. First, to establish a baseline, the natural flow field (without the presence of an upstream wire) was characterized, where experimentally determined values for the stagnation boundary-layer thickness and the velocity profile along the stagnation streamline were both found to agree with the values provided in the literature for two-dimensional cylinders. Subsequently, the dynamics of vorticity collection, growth, amplification, and shedding were studied. The size, stand-off distance and the shedding frequency of the vortical structures forming near the stagnation region were all found to strongly depend on the impingement location of the inbound vorticity on the wheel. A simple relationship between the non
Vortices and superfields on a graph
Kan, Nahomi; Kobayashi, Koichiro; Shiraishi, Kiyoshi
2009-08-15
We extend the dimensional deconstruction by utilizing the knowledge of graph theory. In the dimensional deconstruction, one uses the moose diagram to exhibit the structure of the 'theory space'. We generalize the moose diagram to a general graph with oriented edges. In the present paper, we consider only the U(1) gauge symmetry. We also introduce supersymmetry into our model by use of superfields. We suppose that vector superfields reside at the vertices and chiral superfields at the edges of a given graph. Then we can consider multivector, multi-Higgs models. In our model, [U(1)]{sup p} (where p is the number of vertices) is broken to a single U(1). Therefore, for specific graphs, we get vortexlike classical solutions in our model. We show some examples of the graphs admitting the vortex solutions of simple structure as the Bogomolnyi solution.
Vortices and superfields on a graph
NASA Astrophysics Data System (ADS)
Kan, Nahomi; Kobayashi, Koichiro; Shiraishi, Kiyoshi
2009-08-01
We extend the dimensional deconstruction by utilizing the knowledge of graph theory. In the dimensional deconstruction, one uses the moose diagram to exhibit the structure of the “theory space.” We generalize the moose diagram to a general graph with oriented edges. In the present paper, we consider only the U(1) gauge symmetry. We also introduce supersymmetry into our model by use of superfields. We suppose that vector superfields reside at the vertices and chiral superfields at the edges of a given graph. Then we can consider multivector, multi-Higgs models. In our model, [U(1)]p (where p is the number of vertices) is broken to a single U(1). Therefore, for specific graphs, we get vortexlike classical solutions in our model. We show some examples of the graphs admitting the vortex solutions of simple structure as the Bogomolnyi solution.
NASA Astrophysics Data System (ADS)
Christensen, Neil; Han, Tao; Su, Shufang
2012-06-01
The recent results on Higgs boson searches from LHC experiments provide significant guidance in exploring the minimal supersymmetric (SUSY) standard model (MSSM) Higgs sector. If we accept the existence of a SM-like Higgs boson in the mass window of 123 GeV-127 GeV as indicated by the observed γγ events, there are two distinct mass regions (in mA) left in the MSSM Higgs sector: (a) the lighter CP-even Higgs boson being SM-like and the non-SM-like Higgs bosons all heavy and nearly degenerate above 300 GeV (an extended decoupling region); (b) the heavier CP-even Higgs boson being SM-like and the neutral non-SM-like Higgs bosons all nearly degenerate around 100 GeV (a small non-decoupling region). On the other hand, due to the strong correlation between the Higgs decays to W+W- and to γγ predicted in the MSSM, the apparent absence of a W+W- final state signal is in direct conflict with the γγ peak. If we consider the W+W- channel on its own, the absence of the W+W- signal would imply that the SM-like Higgs boson has reduced coupling to W±, and that the other non-SM-like Higgs bosons should not be too heavy and do not decouple. If both the γγ excess and the absence of a W+W- signal continue, new physics beyond the MSSM will be required. A similar correlation exists between the W+W- and τ+τ- channels: a reduced W+W- channel would force the τ+τ- channel to be larger. Future searches for the SM-like Higgs boson at the LHC will provide critical tests for the MSSM prediction. We also study the signals predicted for the non-SM-like Higgs bosons and emphasize the potential importance of the electroweak processes pp→H+H-, H±A0, which are independent of the SUSY parameters except for their masses. In addition, there may be sizable contributions from pp→H±h0, A0h0 and W±H0, ZH0 in the low-mass non-decoupling region, which may serve to discriminate the model parameters. We allow variations of the relevant SUSY parameters in a broad range and demonstrate the
The Higgs Working Group: Summary report
D. Cavalli et al.
2004-03-18
In this working group we have investigated the prospects for Higgs boson searches at the Tevatron and LHC and, in particular, the potential of these colliders to determine the Higgs properties once these particles have been found. The analyses were done in the framework of the Standard Model (SM) and its supersymmetric extensions as the minimal (MSSM) and next-to-minimal (NMSSM) supersymmetric extensions. The work for the discovery potential of the LHC mainly concentrated on the difficult regions of previous analyses as those which are plagued by invisible Higgs decays and Higgs decays into supersymmetric particles. Moreover, the additional signatures provided by the weak vector-boson fusion process (WBF) have been addressed and found to confirm the results of previous analyses. A major experimental effort has been put onto charged Higgs boson analyses. The final outcome was a significant improvement of the discovery potential at the Tevatron and LHC than previous analyses suggested. For an accurate determination of Higgs boson couplings, the theoretical predictions for the signal and background processes have to be improved. A lot of progress has been made during and after this workshop for the gluon-fusion gg {yields} H + (0, 1, 2jets) and the associated t{bar t}H production process. A thorough study of the present theoretical uncertainties of signal and background processes has been initialized, culminating in a list of open theoretical problems. A problem of major experimental interest is the proper treatment of processes involving bottom quark densities, which is crucial for some important signal and background processes. Further theoretical improvements have been achieved for the MSSM Higgs boson masses and Higgs bosons in the NMSSM. This report summarizes our work. The first part deals with theoretical developments for the signal and background processes. The second part gives an overview of the present status of Higgs boson searches at the Tevatron. The
Numerical study of vorticity-enhanced heat transfer
NASA Astrophysics Data System (ADS)
Wang, Xiaolin; Alben, Silas
2013-11-01
Vortices produced by vibrated reeds and flapping foils can improve heat transfer efficiency in electronic hardware. Vortices enhance forced convection by boundary layer separation and thermal mixing in the bulk flow. In this work, we modeled and simulated the fluid flow and temperature in a 2-D channel flow with vortices injected at the upstream boundary. We classified four types of vortex streets depending on the Reynolds number and vortices' strengths and spacings, and studied the different vortex dynamics in each situation. We then used Lagrangian coherent structures (LCS) to study the effect of the vortices on mixing and determined how the Nusselt number and Coefficients of performance vary with flow parameters and Peclet numbers.
Vorticity imbalance and stability in relation to convection
NASA Technical Reports Server (NTRS)
Read, W. L.; Scoggins, J. R.
1977-01-01
A complete synoptic-scale vorticity budget was related to convection storm development in the eastern two-thirds of the United States. The 3-h sounding interval permitted a study of time changes of the vorticity budget in areas of convective storms. Results of analyses revealed significant changes in values of terms in the vorticity equation at different stages of squall line development. Average budgets for all areas of convection indicate systematic imbalance in the terms in the vorticity equation. This imbalance resulted primarily from sub-grid scale processes. Potential instability in the lower troposphere was analyzed in relation to the development of convective activity. Instability was related to areas of convection; however, instability alone was inadequate for forecast purposes. Combinations of stability and terms in the vorticity equation in the form of indices succeeded in depicting areas of convection better than any one item separately.
Kinematical Compatibility Conditions for Vorticity Across Shock Waves
NASA Astrophysics Data System (ADS)
Baty, Roy
2015-11-01
This work develops the general kinematical compatibility conditions for vorticity across arbitrary shock waves in compressible, inviscid fluids. The vorticity compatibility conditions are derived from the curl of the momentum equation using singular distributions defined on two-dimensional shock wave surfaces embedded in three-dimensional flow fields. The singular distributions are represented as generalized differential operators concentrated on moving shock wave surfaces. The derivation of the compatibility conditions for vorticity requires the application of second-order generalized derivatives and elementary tensor algebra. The well-known vorticity jump conditions across a shock wave are then shown to follow from the general kinematical compatibility conditions for vorticity by expressing the flow field velocity in vectorial components normal and tangential to a shock surface.
Vorticity is a marker of right ventricular diastolic dysfunction.
Fenster, Brett E; Browning, James; Schroeder, Joyce D; Schafer, Michal; Podgorski, Chris A; Smyser, Jamie; Silveira, Lori J; Buckner, J Kern; Hertzberg, Jean R
2015-09-15
Right ventricular diastolic dysfunction (RVDD) is an important prognostic indicator in pulmonary arterial hypertension (PAH). RV vortex rings have been observed in healthy subjects, but their significance in RVDD is unknown. Vorticity, the local spinning motion of an element of fluid, may be a sensitive measure of RV vortex dynamics. Using four-dimensional (4D) flow cardiac magnetic resonance imaging (CMR), we investigated the relationship between right heart vorticity with echocardiographic indexes of RVDD. Thirteen (13) PAH subjects and 10 controls underwent same-day 4D flow CMR and echocardiography. RV diastolic function was assessed using trans-tricuspid valve (TV) early (E) and late (A) velocities, E/A ratio, and e' and a' tissue Doppler velocities. RV and right atrial (RA) integrated mean vorticity was calculated for E and A-wave filling periods using 4D datasets. Compared with controls, A-wave vorticity was significantly increased in RVDD subjects in both the RV [2343 (1,559-3,295) vs. 492 (267-2,649) 1/s, P = 0.028] and RA [30 (27-44) vs. 9 (5-27) 1/s, P = 0.005]. RA E vorticity was significantly decreased [13 (7-22) vs. 28 (15-31) 1/s, P = 0.038] in RVDD. E-wave vorticity correlated TV e', E-,and TV E/A (P < 0.05), and A-wave vorticity associated with both TV A and E/A (P < 0.02). RVDD is associated with alterations in E- and A-wave vorticity, and vorticity correlates with multiple echocardiographic markers of RVDD. Vorticity may be a robust noninvasive research tool for the investigation of RV fluid and tissue mechanical interactions in PAH. PMID:26254331
Large-deviation statistics of vorticity stretching in isotropic turbulence
NASA Astrophysics Data System (ADS)
Johnson, Perry L.; Meneveau, Charles
2016-03-01
A key feature of three-dimensional fluid turbulence is the stretching and realignment of vorticity by the action of the strain rate. It is shown in this paper, using the cumulant-generating function, that the cumulative vorticity stretching along a Lagrangian path in isotropic turbulence obeys a large deviation principle. As a result, the relevant statistics can be described by the vorticity stretching Cramér function. This function is computed from a direct numerical simulation data set at a Taylor-scale Reynolds number of Reλ=433 and compared to those of the finite-time Lyapunov exponents (FTLE) for material deformation. As expected, the mean cumulative vorticity stretching is slightly less than that of the most-stretched material line (largest FTLE), due to the vorticity's preferential alignment with the second-largest eigenvalue of strain rate and the material line's preferential alignment with the largest eigenvalue. However, the vorticity stretching tends to be significantly larger than the second-largest FTLE, and the Cramér functions reveal that the statistics of vorticity stretching fluctuations are more similar to those of the largest FTLE. In an attempt to relate the vorticity stretching statistics to the vorticity magnitude probability density function in statistically stationary conditions, a model Kramers-Moyal equation is constructed using the statistics encoded in the Cramér function. The model predicts a stretched-exponential tail for the vorticity magnitude probability density function, with good agreement for the exponent but significant difference (35%) in the prefactor.
Vortices within vortices: Hierarchical vortex structures in experimental, two-dimensional flow
NASA Astrophysics Data System (ADS)
Kelley, Douglas H.; Ouellette, Nicholas T.
2010-03-01
The topology of a fluid flow is concisely described by its critical points (locations of zero flow) and the manifolds (streamlines) that connect them. Streamlines that carry fluid away from a critical point and then return it to the same critical point from another direction are known as homoclinic manifolds. Rare in three-dimensional flow, homoclinic manifolds are common in two-dimensional flow and form unambiguous topological boundaries useful for defining vortex edges. Approximating two-dimensional flow with an electromagnetically driven, stably stratified solution in a 90 cm x 90 cm pan, we use particle tracking to measure the velocity field and locate its critical points and their manifolds. Strikingly, homoclinic manifolds are often nested --- the flow contains vortices within vortices. Its regions can thus be classified by an embedding number, an integer defined as the depth of vortex nesting. We will discuss the dynamics of this hierarchical vortex embedding number, particularly as a function of flow speed (Reynolds number).
Dynamics of coupled vortices in perpendicular field
Jain, Shikha; Novosad, Valentyn Fradin, Frank Y.; Pearson, John E.; Bader, Samuel D.
2014-02-24
We explore the coupling mechanism of two magnetic vortices in the presence of a perpendicular bias field by pre-selecting the polarity combinations using the resonant-spin-ordering approach. First, out of the four vortex polarity combinations (two of which are degenerate), three stable core polarity states are achieved by lifting the degeneracy of one of the states. Second, the response of the stiffness constant for the vortex pair (similar polarity) in perpendicular bias is found to be asymmetric around the zero field, in contrast to the response obtained from a single vortex core. Finally, the collective response of the system for antiparallel core polarities is symmetric around zero bias. The vortex core whose polarization is opposite to the bias field dominates the response.