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Sample records for bound state embedded

  1. Embedding potentials for excited states of embedded species

    SciTech Connect

    Wesolowski, Tomasz A.

    2014-05-14

    Frozen-Density-Embedding Theory (FDET) is a formalism to obtain the upper bound of the ground-state energy of the total system and the corresponding embedded wavefunction by means of Euler-Lagrange equations [T. A. Wesolowski, Phys. Rev. A 77(1), 012504 (2008)]. FDET provides the expression for the embedding potential as a functional of the electron density of the embedded species, electron density of the environment, and the field generated by other charges in the environment. Under certain conditions, FDET leads to the exact ground-state energy and density of the whole system. Following Perdew-Levy theorem on stationary states of the ground-state energy functional, the other-than-ground-state stationary states of the FDET energy functional correspond to excited states. In the present work, we analyze such use of other-than-ground-state embedded wavefunctions obtained in practical calculations, i.e., when the FDET embedding potential is approximated. Three computational approaches based on FDET, that assure self-consistent excitation energy and embedded wavefunction dealing with the issue of orthogonality of embedded wavefunctions for different states in a different manner, are proposed and discussed.

  2. Bound states and the Bekenstein bound

    SciTech Connect

    Bousso, Raphael

    2003-10-16

    We explore the validity of the generalized Bekenstein bound, S<= pi M a. We define the entropy S as the logarithm of the number of states which have energy eigenvalue below M and are localized to a flat space region of width alpha. If boundary conditions that localize field modes are imposed by fiat, then the bound encounters well-known difficulties with negative Casimir energy and large species number, as well as novel problems arising only in the generalized form. In realistic systems, however, finite-size effects contribute additional energy. We study two different models for estimating such contributions. Our analysis suggests that the bound is both valid and nontrivial if interactions are properly included, so that the entropy S counts the bound states of interacting fields.

  3. Floquet bound states in the continuum

    PubMed Central

    Longhi, Stefano; Valle, Giuseppe Della

    2013-01-01

    Quantum mechanics predicts that certain stationary potentials can sustain bound states with an energy buried in the continuous spectrum of scattered states, the so-called bound states in the continuum (BIC). Originally regarded as mathematical curiosities, BIC have found an increasing interest in recent years, particularly in quantum and classical transport of matter and optical waves in mesoscopic and photonic systems where the underlying potential can be judiciously tailored. Most of our knowledge of BIC is so far restricted to static potentials. Here we introduce a new kind of BIC, referred to as Floquet BIC, which corresponds to a normalizable Floquet state of a time-periodic Hamiltonian with a quasienergy embedded into the spectrum of Floquet scattered states. We discuss the appearance of Floquet BIC states in a tight-binding lattice model driven by an ac field in the proximity of the dynamic localization regime. PMID:23860625

  4. Wronskian Method for Bound States

    ERIC Educational Resources Information Center

    Fernandez, Francisco M.

    2011-01-01

    We propose a simple and straightforward method based on Wronskians for the calculation of bound-state energies and wavefunctions of one-dimensional quantum-mechanical problems. We explicitly discuss the asymptotic behaviour of the wavefunction and show that the allowed energies make the divergent part vanish. As illustrative examples we consider…

  5. Bound anionic states of adenine

    SciTech Connect

    Haranczyk, Maciej; Gutowski, Maciej S; Li, Xiang; Bowen, Kit H

    2007-03-20

    Anionic states of nucleic acid bases are involved in DNA damage by low-energy electrons and in charge transfer through DNA. Previous gas phase studies of free, unsolvated nucleic acid base parent anions probed only dipole-bound states, which are not present in condensed phase environments, but did not observe valence anionic states, which for purine bases, are thought to be adiabatically unbound. Contrary to this expectation, we have demonstrated that some thus far ignored tautomers of adenine, which result from enamine-imine transformations, support valence anionic states with electron vertical detachment energies as large as 2.2 eV, and at least one of these anionic tautomers is adiabatically bound. Moreover, we predict that the new anionic tautomers should also dominate in solutions and should be characterized by larger values of electron vertical detachment energy than the canonical valence anion. All of the new-found anionic tautomers might be formed in the course of dissociative electron attachment followed by a hydrogen atom attachment to a carbon atom, and they might affect the structure and properties of DNA and RNA exposed to low-energy electrons. The discovery of these valence anionic states of adenine was facilitated by the development of: (i) a new experimental method for preparing parent anions of nucleic acid bases for photoelectron experiments, and (ii) a new combinatorial/ quantum chemical approach for identification of the most stable tautomers of organic molecules. The computational portion of this work was supported by the: (i) Polish State Committee for Scientific Research (KBN) Grants: DS/8000-4-0140-7 (M.G.) and N204 127 31/2963 (M.H.), (ii) European Social Funds (EFS) ZPORR/2.22/II/2.6/ARP/U/2/05 (M.H.), and (iii) US DOE Office of Biological and Environmental Research, Low Dose Radiation Research Program (M.G.). M.H. holds the Foundation for Polish Science (FNP) award for young scientists. The calculations were performed at the Academic

  6. Bound states of heavy flavor hyperons

    NASA Astrophysics Data System (ADS)

    Frömel, F.; Juliá-Díaz, B.; Riska, D. O.

    2005-04-01

    Several realistic phenomenological nucleon-nucleon interaction models are employed to investigate the possibility of bound deuteron-like states of such heavy flavor hyperons and nucleons, for which the interaction between the light flavor quark components is expected to be the most significant interaction. The results indicate that deuteron-like bound states are likely to form between nucleons and the Ξc' and Ξ charm hyperons as well as between Ξ hyperons and double-charm hyperons. Bound states between two Σ hyperons are also likely. In the case of beauty hyperons the corresponding states are likely to be deeply bound.

  7. Majorana bound states in magnetic skyrmions

    NASA Astrophysics Data System (ADS)

    Yang, Guang; Stano, Peter; Klinovaja, Jelena; Loss, Daniel

    2016-06-01

    Magnetic skyrmions are highly mobile nanoscale topological spin textures. We show, both analytically and numerically, that a magnetic skyrmion of an even azimuthal winding number placed in proximity to an s -wave superconductor hosts a zero-energy Majorana bound state in its core, when the exchange coupling between the itinerant electrons and the skyrmion is strong. This Majorana bound state is stabilized by the presence of a spin-orbit interaction. We propose the use of a superconducting trijunction to realize non-Abelian statistics of such Majorana bound states.

  8. Soliton bound states in semiconductor disk laser

    NASA Astrophysics Data System (ADS)

    Viktorov, Evgeny A.; Butkus, Mantas; Erneux, Thomas; Hamilton, Craig J.; Malcolm, Graeme P. A.; Rafailov, Edik U.

    2014-05-01

    We report what we believe is the first demonstration of a temporal soliton bound state in semiconductor disk laser. The laser was passively mode-locked using a quantum dot based semiconductor saturable absorber mirror (QD-SESAM). Two mode-locking regimes were observed where the laser would emit single or closely spaced double pulses (soliton bound state regime) per cavity round-trip. The pulses in soliton bound state regime were spaced by discrete, fixed time duration. We use a system of delay differential equations to model the dynamics of our device.

  9. Hamiltonian anomalies of bound states in QED

    SciTech Connect

    Shilin, V. I.; Pervushin, V. N.

    2013-10-15

    The Bound State in QED is described in systematic way by means of nonlocal irreducible representations of the nonhomogeneous Poincare group and Dirac's method of quantization. As an example of application of this method we calculate triangle diagram Para-Positronium {yields} {gamma}{gamma}. We show that the Hamiltonian approach to Bound State in QED leads to anomaly-type contribution to creation of pair of parapositronium by two photon.

  10. Bound States in Boson Impurity Models

    NASA Astrophysics Data System (ADS)

    Shi, Tao; Wu, Ying-Hai; González-Tudela, A.; Cirac, J. I.

    2016-04-01

    The formation of bound states involving multiple particles underlies many interesting quantum physical phenomena, such as Efimov physics or superconductivity. In this work, we show the existence of an infinite number of such states for some boson impurity models. They describe free bosons coupled to an impurity and include some of the most representative models in quantum optics. We also propose a family of wave functions to describe the bound states and verify that it accurately characterizes all parameter regimes by comparing its predictions with exact numerical calculations for a one-dimensional tight-binding Hamiltonian. For that model, we also analyze the nature of the bound states by studying the scaling relations of physical quantities, such as the ground-state energy and localization length, and find a nonanalytical behavior as a function of the coupling strength. Finally, we discuss how to test our theoretical predictions in experimental platforms, such as photonic crystal structures and cold atoms in optical lattices.

  11. Bound states in continuum: Quantum dots in a quantum well

    NASA Astrophysics Data System (ADS)

    Prodanović, Nikola; Milanović, Vitomir; Ikonić, Zoran; Indjin, Dragan; Harrison, Paul

    2013-11-01

    We report on the existence of a bound state in the continuum (BIC) of quantum rods (QR). QRs are novel elongated InGaAs quantum dot nanostructures embedded in the shallower InGaAs quantum well. BIC appears as an excited confined dot state and energetically above the bottom of a well subband continuum. We prove that high height-to-diameter QR aspect ratio and the presence of a quantum well are indispensable conditions for accommodating the BIC. QRs are unique semiconductor nanostructures, exhibiting this mathematical curiosity predicted 83 years ago by Wigner and von Neumann.

  12. Bound States in ``Majorana Box''

    NASA Astrophysics Data System (ADS)

    Albrecht, Sven; Higginbotham, Andrew; Kuemmeth, Ferdinand; Krogstrup, Peter; Jespersen, Thomas; Nygård, Jesper; Marcus, Charles

    2015-03-01

    We perform bias spectroscopy and observe Coulomb peak motion in InAs quantum dots with an epitaxial superconducting aluminum shell. Varying the length of the aluminum shell and applying a magnetic field, we are able to tune between regimes with 2e and 1e-periodic Coulomb oscillations. The doubling in periodicity reflects a transition from two-electron tunneling to single quasiparticle charging, attributable to a competition between the charging energy and the superconducting energy gap. At high fields below the superconducting-to-normal transition, we observe low-lying features in bias and 1e-periodic Coulomb peaks, both consistent with the presence of a zero-energy discrete state. We discuss these results in the context of proposed experimental signatures of Majorana fermions. Research supported by Microsoft Station Q, Danish National Research Foundation, Villum Foundation, Lundbeck Foundation, and the European Commission.

  13. Graph Embedding Techniques for Bounding Condition Numbers of Incomplete Factor Preconditioning

    NASA Technical Reports Server (NTRS)

    Guattery, Stephen

    1997-01-01

    We extend graph embedding techniques for bounding the spectral condition number of preconditioned systems involving symmetric, irreducibly diagonally dominant M-matrices to systems where the preconditioner is not diagonally dominant. In particular, this allows us to bound the spectral condition number when the preconditioner is based on an incomplete factorization. We provide a review of previous techniques, describe our extension, and give examples both of a bound for a model problem, and of ways in which our techniques give intuitive way of looking at incomplete factor preconditioners.

  14. Construction of bound entangled states based on permutation operators

    NASA Astrophysics Data System (ADS)

    Zhao, Hui; Guo, Sha; Jing, Naihuan; Fei, Shaoming

    2016-04-01

    We present a construction of new bound entangled states from given bound entangled states for arbitrary dimensional bipartite systems. One way to construct bound entangled states is to show that these states are positive partial transpose (PPT) and violate the range criterion at the same time. By applying certain operators to given bound entangled states or to one of the subsystems of the given bound entangled states, we obtain a set of new states which are both PPT and violate the range criterion. We show that the derived bound entangled states are not local unitary equivalent to the original bound entangled states by detail examples.

  15. Bounds for state-dependent quantum cloning

    SciTech Connect

    Han Yongjian; Zhang Yongsheng; Guo Guangcan

    2002-11-01

    Due to the no-cloning theorem, the unknown quantum state can only be cloned approximately or exactly with some probability. There are two types of cloners: universal and state-dependent cloner. The optimal universal cloner has been found and can be viewed as a special state-dependent quantum cloner that has no information about the states. In this paper, we investigate the state-dependent cloning when the state set contains more than two states. We get some bounds of the global fidelity for these processes. This method is not dependent on the number of the states contained in the state set. It is also independent of the numbers of copying.

  16. The bound states of ultracold KRb molecules

    NASA Astrophysics Data System (ADS)

    Julienne, Paul; Hanna, Thomas

    2009-03-01

    Recently ultracold vibrational ground state ^40K^87Rb polar molecules have been made using magnetoassociation of two cold atoms to a weakly bound Feshbach molecule, followed by a two-color optical STIRAP process to transfer molecules to the molecular ground state [1]. We have used accurate potential energy curves for the singlet and triplet states of the KRb molecule [2] with coupled channels calculations to calculate all of the bound states of the ^40K^87Rb molecule as a function of magnetic field from the cold atom collision threshold to the v=0 ground state. We have also developed approximate models for understanding the changing properties of the molecular bound states as binding energy increases. Some overall conclusions from these calculations will be presented. [1] K.-K. Ni, S. Ospelkaus, M. H. G. de Miranda, A. Peer, B. Neyenhuis, J. J. Zirbel, S. Kotochigova, P. S. Julienne, D. S. Jin, and J. Ye, Science, 2008, 322, 231--235. [2] A. Pashov, O. Docenko, M. Tamanis, R. Ferber, H. Kn"ockel, and E. Tiemann, Phys. Rev. A, 2007, 76, 022511.

  17. Andreev-Majorana bound states in superfluids

    SciTech Connect

    Silaev, M. A. Volovik, G. E.

    2014-12-15

    We consider Andreev-Majorana (AM) bound states with zero energy on surfaces, interfaces, and vortices in different phases of the p-wave superfluids. We discuss the chiral superfluid {sup 3}He-A and time reversal invariant phases: superfluid {sup 3}He-B, planar and polar phases. The AM zero modes are determined by topology in the bulk and disappear at the quantum phase transition from the topological to nontopological state of the superfluid. The topology demonstrates the interplay of dimensions. In particular, the zero-dimensional Weyl points in chiral superfluids (the Berry phase monopoles in momentum space) give rise to the one-dimensional Fermi arc of AM bound states on the surface and to the one-dimensional flat band of AM modes in the vortex core. The one-dimensional nodal line in the polar phase produces a two-dimensional flat band of AM modes on the surface. The interplay of dimensions also connects the AM states in superfluids with different dimensions. For example, the topological properties of the spectrum of bound states in three-dimensional {sup 3}He-B are connected to the properties of the spectrum in the two-dimensional planar phase (thin film)

  18. Tsirelson's bound and supersymmetric entangled states

    PubMed Central

    Borsten, L.; Brádler, K.; Duff, M. J.

    2014-01-01

    A superqubit, belonging to a (2|1)-dimensional super-Hilbert space, constitutes the minimal supersymmetric extension of the conventional qubit. In order to see whether superqubits are more non-local than ordinary qubits, we construct a class of two-superqubit entangled states as a non-local resource in the CHSH game. Since super Hilbert space amplitudes are Grassmann numbers, the result depends on how we extract real probabilities and we examine three choices of map: (1) DeWitt (2) Trigonometric and (3) Modified Rogers. In cases (1) and (2), the winning probability reaches the Tsirelson bound pwin=cos2π/8≃0.8536 of standard quantum mechanics. Case (3) crosses Tsirelson's bound with pwin≃0.9265. Although all states used in the game involve probabilities lying between 0 and 1, case (3) permits other changes of basis inducing negative transition probabilities. PMID:25294964

  19. Tsirelson's bound and supersymmetric entangled states.

    PubMed

    Borsten, L; Brádler, K; Duff, M J

    2014-10-01

    A superqubit, belonging to a (2|1)-dimensional super-Hilbert space, constitutes the minimal supersymmetric extension of the conventional qubit. In order to see whether superqubits are more non-local than ordinary qubits, we construct a class of two-superqubit entangled states as a non-local resource in the CHSH game. Since super Hilbert space amplitudes are Grassmann numbers, the result depends on how we extract real probabilities and we examine three choices of map: (1) DeWitt (2) Trigonometric and (3) Modified Rogers. In cases (1) and (2), the winning probability reaches the Tsirelson bound [Formula: see text] of standard quantum mechanics. Case (3) crosses Tsirelson's bound with p win≃0.9265. Although all states used in the game involve probabilities lying between 0 and 1, case (3) permits other changes of basis inducing negative transition probabilities. PMID:25294964

  20. Weakly bound states in heterogeneous waveguides

    NASA Astrophysics Data System (ADS)

    Amore, Paolo; Fernández, Francisco M.; Hofmann, Christoph P.

    2016-07-01

    We study the spectrum of the Helmholtz equation in a two-dimensional infinite waveguide, containing a weak heterogeneity localized at an internal point, and obeying Dirichlet boundary conditions at its border. We use the variational theorem to derive the condition for which the lowest eigenvalue of the spectrum falls below the continuum threshold and a bound state appears, localized at the heterogeneity. We devise a rigorous perturbation scheme and derive the exact expression for the energy to third order in the heterogeneity.

  1. Entanglement bound for multipartite pure states based on local measurements

    SciTech Connect

    Jiang Lizhen; Chen Xiaoyu; Ye Tianyu

    2011-10-15

    An entanglement bound based on local measurements is introduced for multipartite pure states. It is the upper bound of the geometric measure and the relative entropy of entanglement. It is the lower bound of the minimal-measurement entropy. For pure bipartite states, the bound is equal to the entanglement entropy. The bound is applied to pure tripartite qubit states and the exact tripartite relative entropy of entanglement is obtained for a wide class of states.

  2. Andreev bound states. Some quasiclassical reflections

    SciTech Connect

    Lin, Y. Leggett, A. J.

    2014-12-15

    We discuss a very simple and essentially exactly solvable model problem which illustrates some nice features of Andreev bound states, namely, the trapping of a single Bogoliubov quasiparticle in a neutral s-wave BCS superfluid by a wide and shallow Zeeman trap. In the quasiclassical limit, the ground state is a doublet with a splitting which is proportional to the exponentially small amplitude for “normal” reflection by the edges of the trap. We comment briefly on a prima facie paradox concerning the continuity equation and conjecture a resolution to it.

  3. Andreev bound states. Some quasiclassical reflections

    NASA Astrophysics Data System (ADS)

    Lin, Y.; Leggett, A. J.

    2014-12-01

    We discuss a very simple and essentially exactly solvable model problem which illustrates some nice features of Andreev bound states, namely, the trapping of a single Bogoliubov quasiparticle in a neutral s-wave BCS superfluid by a wide and shallow Zeeman trap. In the quasiclassical limit, the ground state is a doublet with a splitting which is proportional to the exponentially small amplitude for "normal" reflection by the edges of the trap. We comment briefly on a prima facie paradox concerning the continuity equation and conjecture a resolution to it.

  4. Bounds on internal state variables in viscoplasticity

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    1993-01-01

    A typical viscoplastic model will introduce up to three types of internal state variables in order to properly describe transient material behavior; they are as follows: the back stress, the yield stress, and the drag strength. Different models employ different combinations of these internal variables--their selection and description of evolution being largely dependent on application and material selection. Under steady-state conditions, the internal variables cease to evolve and therefore become related to the external variables (stress and temperature) through simple functional relationships. A physically motivated hypothesis is presented that links the kinetic equation of viscoplasticity with that of creep under steady-state conditions. From this hypothesis one determines how the internal variables relate to one another at steady state, but most importantly, one obtains bounds on the magnitudes of stress and back stress, and on the yield stress and drag strength.

  5. Concurrent quantification of multiple nanoparticle bound states

    PubMed Central

    Rauwerdink, Adam M.; Weaver, John B.

    2011-01-01

    Purpose: The binding of nanoparticles to in vivo targets impacts their use for medical imaging, therapy, and the study of diseases and disease biomarkers. Though an array of techniques can detect binding in vitro, the search for a robust in vivo method continues. The spectral response of magnetic nanoparticles can be influenced by a variety of changes in their physical environment including viscosity and binding. Here, the authors show that nanoparticles in these different environmental states produce spectral responses, which are sufficiently unique to allow for simultaneous quantification of the proportion of nanoparticles within each state. Methods: The authors measured the response to restricted Brownian motion using an array of magnetic nanoparticle designs. With a chosen optimal particle type, the authors prepared particle samples in three distinct environmental states. Various combinations of particles within these three states were measured concurrently and the authors attempted to solve for the quantity of particles within each physical state. Results: The authors found the spectral response of the nanoparticles to be sufficiently unique to allow for accurate quantification of up to three bound states with errors on the order of 1.5%. Furthermore, the authors discuss numerous paths for translating these measurements to in vivo applications. Conclusions: Multiple nanoparticle environmental states can be concurrently quantified using the spectral response of the particles. Such an ability, if translated to the in vivo realm, could provide valuable information about the fate of nanoparticles in vivo or improve the efficacy of nanoparticle based treatments. PMID:21520825

  6. Nonlocal spectroscopy of Andreev bound states

    NASA Astrophysics Data System (ADS)

    Schindele, J.; Baumgartner, A.; Maurand, R.; Weiss, M.; Schönenberger, C.

    2014-01-01

    We experimentally investigate Andreev bound states (ABSs) in a carbon nanotube quantum dot (QD) connected to a superconducting Nb lead (S). A weakly coupled normal metal contact acts as a tunnel probe that measures the energy dispersion of the ABSs. Moreover, we study the response of the ABS to nonlocal transport processes, namely, Cooper pair splitting and elastic co-tunnelling, which are enabled by a second QD fabricated on the same nanotube on the opposite side of S. We find an appreciable nonlocal conductance with a rich structure, including a sign reversal at the ground-state transition from the ABS singlet to a degenerate magnetic doublet. We describe our device by a simple rate equation model that captures the key features of our observations and demonstrates that the sign of the nonlocal conductance is a measure for the charge distribution of the ABS, given by the respective Bogoliubov-de Gennes amplitudes u and v.

  7. Integral Equations and the Bound-State Problem.

    ERIC Educational Resources Information Center

    Bagchi, B.; Seyler, R. G.

    1980-01-01

    An integral equation for the s-wave bound-state solution is derived and then solved for a square-well potential. It is shown that the scattering solutions continue to exist at negative energies, and when evaluated at the energy of a bound state these solutions do reduce to the bound-state solution.

  8. Unified treatment of bound-state and scattering problems

    SciTech Connect

    Adhikari, S.K.; Tomio, L.

    1988-01-01

    The iteration-subtraction method for the unified treatment of bound-state and scattering problems is compared and contrasted with a similar method for the two-body bound-state problem via nonsingular scattering equations developed recently. We also compare another recent method for solving bound-state problems with the iteration-subtraction method.

  9. Fingerprints of Majorana Bound States in Aharonov-Bohm Geometry.

    PubMed

    Tripathi, Krashna Mohan; Das, Sourin; Rao, Sumathi

    2016-04-22

    We study a ring geometry, coupled to two normal metallic leads, which has a Majorana bound state (MBS) embedded in one of its arms and is threaded by Aharonov-Bohm (AB) flux ϕ. We show that by varying the AB flux, the two leads go through resonance in an anticorrelated fashion while the resonance conductance is quantized to 2e^{2}/h. We further show that such anticorrelation is completely absent when the MBS is replaced by an Andreev bound state (ABS). Hence this anti-correlation in conductance when studied as a function of ϕ provides a unique signature of the MBS which cannot be faked by an ABS. We contrast the phase sensitivity of the MBS and ABS in terms of tunneling conductances. We argue that the relative phase between the tunneling amplitude of the electrons and holes from either lead to the level (MBS or ABS), which is constrained to 0,π for the MBS and unconstrained for the ABS, is responsible for this interesting contrast in the AB effect between the MBS and ABS. PMID:27152813

  10. Fingerprints of Majorana Bound States in Aharonov-Bohm Geometry

    NASA Astrophysics Data System (ADS)

    Tripathi, Krashna Mohan; Das, Sourin; Rao, Sumathi

    2016-04-01

    We study a ring geometry, coupled to two normal metallic leads, which has a Majorana bound state (MBS) embedded in one of its arms and is threaded by Aharonov-Bohm (A B ) flux ϕ . We show that by varying the A B flux, the two leads go through resonance in an anticorrelated fashion while the resonance conductance is quantized to 2 e2/h . We further show that such anticorrelation is completely absent when the MBS is replaced by an Andreev bound state (ABS). Hence this anti-correlation in conductance when studied as a function of ϕ provides a unique signature of the MBS which cannot be faked by an ABS. We contrast the phase sensitivity of the MBS and ABS in terms of tunneling conductances. We argue that the relative phase between the tunneling amplitude of the electrons and holes from either lead to the level (MBS or ABS), which is constrained to 0 ,π for the MBS and unconstrained for the ABS, is responsible for this interesting contrast in the A B effect between the MBS and ABS.

  11. Critical field enhancement of asymptotic optical bound states in the continuum

    PubMed Central

    Yoon, Jae Woong; Song, Seok Ho; Magnusson, Robert

    2015-01-01

    We study spectral singularities and critical field enhancement factors associated with embedded photonic bound states in subwavelength periodic Si films. Ultrahigh-Q resonances supporting field enhancement factor exceeding 108 are obtained in the spectral vicinity of exact embedded eigenvalues in spite of deep surface modulation and vertical asymmetry of the given structure. Treating relations between the partial resonance Q and field enhancement factors with an analytical coupled-mode model, we derive a general strategy to maximize the field enhancement associated with these photonic bound states in the presence of material dissipation. The analytical expression for the field enhancement quantitatively agrees with rigorous numerical calculations. Therefore, our results provide a general knowledge for designing practical resonance elements based on optical bound states in the continuum in various applications. PMID:26673548

  12. Critical field enhancement of asymptotic optical bound states in the continuum.

    PubMed

    Yoon, Jae Woong; Song, Seok Ho; Magnusson, Robert

    2015-01-01

    We study spectral singularities and critical field enhancement factors associated with embedded photonic bound states in subwavelength periodic Si films. Ultrahigh-Q resonances supporting field enhancement factor exceeding 10(8) are obtained in the spectral vicinity of exact embedded eigenvalues in spite of deep surface modulation and vertical asymmetry of the given structure. Treating relations between the partial resonance Q and field enhancement factors with an analytical coupled-mode model, we derive a general strategy to maximize the field enhancement associated with these photonic bound states in the presence of material dissipation. The analytical expression for the field enhancement quantitatively agrees with rigorous numerical calculations. Therefore, our results provide a general knowledge for designing practical resonance elements based on optical bound states in the continuum in various applications. PMID:26673548

  13. Critical field enhancement of asymptotic optical bound states in the continuum

    NASA Astrophysics Data System (ADS)

    Yoon, Jae Woong; Song, Seok Ho; Magnusson, Robert

    2015-12-01

    We study spectral singularities and critical field enhancement factors associated with embedded photonic bound states in subwavelength periodic Si films. Ultrahigh-Q resonances supporting field enhancement factor exceeding 108 are obtained in the spectral vicinity of exact embedded eigenvalues in spite of deep surface modulation and vertical asymmetry of the given structure. Treating relations between the partial resonance Q and field enhancement factors with an analytical coupled-mode model, we derive a general strategy to maximize the field enhancement associated with these photonic bound states in the presence of material dissipation. The analytical expression for the field enhancement quantitatively agrees with rigorous numerical calculations. Therefore, our results provide a general knowledge for designing practical resonance elements based on optical bound states in the continuum in various applications.

  14. Bound states in a strong magnetic field

    SciTech Connect

    Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G.; Ferreira Filho, L. G.

    2013-03-25

    We expect a strong magnetic field to be produced in the perpendicular direction to the reaction plane, in a noncentral heavy-ion collision . The strength of the magnetic field is estimated to be eB{approx}m{sup 2}{sub {pi}}{approx} 0.02 GeV{sup 2} at the RHIC and eB{approx} 15m{sup 2}{sub {pi}}{approx} 0.3 GeV{sup 2} at the LHC. We investigate the effects of the magnetic field on B{sup 0} and D{sup 0} mesons, focusing on the changes of the energy levels and of the mass of the bound states.

  15. Nonvalence correlation-bound anion states of spherical fullerenes.

    PubMed

    Voora, Vamsee K; Jordan, Kenneth D

    2014-08-13

    We present a one-electron model Hamiltonian for characterizing nonvalence correlation-bound anion states of fullerene molecules. These states are the finite system analogs of image potential states of metallic surfaces. The model potential accounts for both atomic and charge-flow polarization and is used to characterize the nonvalence correlation-bound anion states of the C60, (C60)2, C240, and C60@C240 fullerene systems. Although C60 is found to have a single (s-type) nonvalence correlation-bound anion state, the larger fullerenes are demonstrated to have multiple nonvalence correlation-bound anion states. PMID:24978808

  16. Real weights, bound states and duality orbits

    NASA Astrophysics Data System (ADS)

    Marrani, Alessio; Riccioni, Fabio; Romano, Luca

    2016-01-01

    We show that the duality orbits of extremal black holes in supergravity theories with symmetric scalar manifolds can be derived by studying the stabilizing subalgebras of suitable representatives, realized as bound states of specific weight vectors of the corresponding representation of the duality symmetry group. The weight vectors always correspond to weights that are real, where the reality properties are derived from the Tits-Satake diagram that identifies the real form of the Lie algebra of the duality symmetry group. Both 𝒩 = 2 magic Maxwell-Einstein supergravities and the semisimple infinite sequences of 𝒩 = 2 and 𝒩 = 4 theories in D = 4 and 5 are considered, and various results, obtained over the years in the literature using different methods, are retrieved. In particular, we show that the stratification of the orbits of these theories occurs because of very specific properties of the representations: in the case of the theory based on the real numbers, whose symmetry group is maximally noncompact and therefore all the weights are real, the stratification is due to the presence of weights of different lengths, while in the other cases it is due to the presence of complex weights.

  17. Viewing Majorana Bound States by Rabi Oscillations

    PubMed Central

    Wang, Zhi; Liang, Qi-Feng; Yao, Dao-Xin; Hu, Xiao

    2015-01-01

    We propose to use Rabi oscillation as a probe to view the fractional Josepshon relation (FJR) associated with Majorana bound states (MBSs) expected in one-dimensional topological superconductors. The system consists of a quantum dot (QD) and an rf-SQUID with MBSs at the Josephson junction. Rabi oscillations between energy levels formed by MBSs are induced by ac gate voltage controlling the coupling between QD and MBS when the photon energy proportional to the ac frequency matches gap between quantum levels formed by MBSs and QD. As a manifestation of the Rabi oscillation in the whole system involving MBSs, the electron occupation on QD oscillates with time, which can be measured by charge sensing techniques. With Floquet theorem and numerical analysis we reveal that from the resonant driving frequency for coherent Rabi oscillation one can directly map out the FJR cos(πΦ/Φ0) as a signature of MBSs, with Φ the magnetic flux through SQUID and Φ0 = hc/2e the flux quantum. The present scheme is expected to provide a clear evidence for MBSs under intensive searching. PMID:26153250

  18. Viewing Majorana Bound States by Rabi Oscillations

    NASA Astrophysics Data System (ADS)

    Wang, Zhi; Liang, Qi-Feng; Yao, Dao-Xin; Hu, Xiao

    2015-07-01

    We propose to use Rabi oscillation as a probe to view the fractional Josepshon relation (FJR) associated with Majorana bound states (MBSs) expected in one-dimensional topological superconductors. The system consists of a quantum dot (QD) and an rf-SQUID with MBSs at the Josephson junction. Rabi oscillations between energy levels formed by MBSs are induced by ac gate voltage controlling the coupling between QD and MBS when the photon energy proportional to the ac frequency matches gap between quantum levels formed by MBSs and QD. As a manifestation of the Rabi oscillation in the whole system involving MBSs, the electron occupation on QD oscillates with time, which can be measured by charge sensing techniques. With Floquet theorem and numerical analysis we reveal that from the resonant driving frequency for coherent Rabi oscillation one can directly map out the FJR cos(πΦ/Φ0) as a signature of MBSs, with Φ the magnetic flux through SQUID and Φ0 = hc/2e the flux quantum. The present scheme is expected to provide a clear evidence for MBSs under intensive searching.

  19. Orthogonality of embedded wave functions for different states in frozen-density embedding theory.

    PubMed

    Zech, Alexander; Aquilante, Francesco; Wesolowski, Tomasz A

    2015-10-28

    Other than lowest-energy stationary embedded wave functions obtained in Frozen-Density Embedding Theory (FDET) [T. A. Wesolowski, Phys. Rev. A 77, 012504 (2008)] can be associated with electronic excited states but they can be mutually non-orthogonal. Although this does not violate any physical principles--embedded wave functions are only auxiliary objects used to obtain stationary densities--working with orthogonal functions has many practical advantages. In the present work, we show numerically that excitation energies obtained using conventional FDET calculations (allowing for non-orthogonality) can be obtained using embedded wave functions which are strictly orthogonal. The used method preserves the mathematical structure of FDET and self-consistency between energy, embedded wave function, and the embedding potential (they are connected through the Euler-Lagrange equations). The orthogonality is built-in through the linearization in the embedded density of the relevant components of the total energy functional. Moreover, we show formally that the differences between the expectation values of the embedded Hamiltonian are equal to the excitation energies, which is the exact result within linearized FDET. Linearized FDET is shown to be a robust approximation for a large class of reference densities. PMID:26520497

  20. Orthogonality of embedded wave functions for different states in frozen-density embedding theory

    SciTech Connect

    Zech, Alexander; Wesolowski, Tomasz A.; Aquilante, Francesco

    2015-10-28

    Other than lowest-energy stationary embedded wave functions obtained in Frozen-Density Embedding Theory (FDET) [T. A. Wesolowski, Phys. Rev. A 77, 012504 (2008)] can be associated with electronic excited states but they can be mutually non-orthogonal. Although this does not violate any physical principles — embedded wave functions are only auxiliary objects used to obtain stationary densities — working with orthogonal functions has many practical advantages. In the present work, we show numerically that excitation energies obtained using conventional FDET calculations (allowing for non-orthogonality) can be obtained using embedded wave functions which are strictly orthogonal. The used method preserves the mathematical structure of FDET and self-consistency between energy, embedded wave function, and the embedding potential (they are connected through the Euler-Lagrange equations). The orthogonality is built-in through the linearization in the embedded density of the relevant components of the total energy functional. Moreover, we show formally that the differences between the expectation values of the embedded Hamiltonian are equal to the excitation energies, which is the exact result within linearized FDET. Linearized FDET is shown to be a robust approximation for a large class of reference densities.

  1. Bound states in a hyperbolic asymmetric double-well

    SciTech Connect

    Hartmann, R. R.

    2014-01-15

    We report a new class of hyperbolic asymmetric double-well whose bound state wavefunctions can be expressed in terms of confluent Heun functions. An analytic procedure is used to obtain the energy eigenvalues and the criterion for the potential to support bound states is discussed.

  2. Volume Dependence of Bound States with Angular Momentum

    SciTech Connect

    Koenig, Sebastian; Hammer, H.-W.; Lee, Dean

    2011-09-09

    We derive general results for the mass shift of bound states with angular momentum l{>=}1 in a finite periodic volume. Our results have direct applications to lattice simulations of hadronic molecules as well as atomic nuclei. While the binding of S-wave bound states increases at finite volume, we show that the binding of P-wave bound states decreases. The mass shift for D-wave bound states as well as higher partial waves depends on the representation of the cubic rotation group. Nevertheless, the multiplet-averaged mass shift for any angular momentum l can be expressed in a simple form, and the sign of the shift alternates for even and odd l. We verify our analytical results with explicit numerical calculations. We also show numerically that similar volume corrections appear in three-body bound states.

  3. Scattering, bound, and quasi-bound states of the generalized symmetric Woods-Saxon potential

    NASA Astrophysics Data System (ADS)

    Lütfüoǧlu, B. C.; Akdeniz, F.; Bayrak, O.

    2016-03-01

    The exact analytical solutions of the Schrödinger equation for the generalized symmetrical Woods-Saxon potential are examined for the scattering, bound, and quasi-bound states in one dimension. The reflection and transmission coefficients are analytically obtained. Then, the correlations between the potential parameters and the reflection-transmission coefficients are investigated, and a transmission resonance condition is derived. Occurrence of the transmission resonance has been shown when incident energy of the particle is equal to one of the resonance energies of the quasi-bound states.

  4. Threshold for formation of atom-photon bound states in a coherent photonic band-gap reservoir

    NASA Astrophysics Data System (ADS)

    Wu, Yunan; Wang, Jing; Zhang, Hanzhuang

    2016-05-01

    We study the threshold for the formation of atom-photon bound (APB) states from a two-level atom embedded in a coherent photonic band-gap (PBG) reservoir. It is shown that the embedded position of the atom plays an important role in the threshold. By varying the atomic embedded position, a part of formation range of APB states can be moved from inside to outside the band gap. The direct link between the steady-state entanglement and APB states is also investigated. We show that the values of entanglement between reservoir modes reflect the amount of bounded energy caused by APB states. The feasible experimental systems for verifying the above phenomena are discussed. Our results provide a clear clue on how to form and control APB states in PBG materials.

  5. Precise and Efficient Static Array Bound Checking for Large Embedded C Programs

    NASA Technical Reports Server (NTRS)

    Venet, Arnaud

    2004-01-01

    In this paper we describe the design and implementation of a static array-bound checker for a family of embedded programs: the flight control software of recent Mars missions. These codes are large (up to 250 KLOC), pointer intensive, heavily multithreaded and written in an object-oriented style, which makes their analysis very challenging. We designed a tool called C Global Surveyor (CGS) that can analyze the largest code in a couple of hours with a precision of 80%. The scalability and precision of the analyzer are achieved by using an incremental framework in which a pointer analysis and a numerical analysis of array indices mutually refine each other. CGS has been designed so that it can distribute the analysis over several processors in a cluster of machines. To the best of our knowledge this is the first distributed implementation of static analysis algorithms. Throughout the paper we will discuss the scalability setbacks that we encountered during the construction of the tool and their impact on the initial design decisions.

  6. Excited states in large molecular systems through polarizable embedding.

    PubMed

    List, Nanna Holmgaard; Olsen, Jógvan Magnus Haugaard; Kongsted, Jacob

    2016-07-27

    In this perspective, we provide an overview of recent work within the polarizable embedding scheme to describe properties of molecules in realistic environments of increasing complexity. After an outline of the theoretical basis for the polarizable embedding model, we discuss the importance of using an accurate embedding potential, and how this may be used to significantly reduce the size of the part of the system treated using quantum mechanics without compromising the accuracy of the final results. Furthermore, we discuss the calculation of local electronic excited states based on response theory. We finally discuss aspects related to two recent extensions of the model (i) effective external field and (ii) polarizable density embedding emphasizing their importance for efficient yet accurate description of excited-state properties in complex environments. PMID:27416749

  7. Emergence of bound states in ballistic magnetotransport of graphene antidots

    NASA Astrophysics Data System (ADS)

    Rakyta, P.; Tóvári, E.; Csontos, M.; Csonka, Sz.; Csordás, A.; Cserti, J.

    2014-09-01

    An experimental method for detection of bound states around an antidot formed by a hole in a graphene sheet is proposed via measuring the ballistic two-terminal conductance. In particular, we consider the effect of bound states formed by a magnetic field on the two-terminal conductance and show that one can observe Breit-Wigner-like resonances in the conductance as a function of the Fermi level close to the energies of the bound states. In addition, we develop a numerical method utilizing a reduced computational effort compared to the existing numerical recursive Green's function methods.

  8. Quasi-bound states in strained graphene

    NASA Astrophysics Data System (ADS)

    Bahamon, Dario; Qi, Zenan; Park, Harold; Pareira, Vitor; Campbell, David

    In this work, we explore the possibility of manipulating electronic states in graphene nanostructures by mechanical means. Specifically, we use molecular dynamics and tight-binding models to access the electronic and transport properties of strained graphene nanobubbles and graphene kirigami. We establish that low energy electrons can be confined in the arms of the kirigami and within the nanobubbles; under different load conditions the coupling between confined states and continuous states is modified creating different conductance line-shapes.

  9. Electron teleportation via Majorana bound states in a mesoscopic superconductor.

    PubMed

    Fu, Liang

    2010-02-01

    Zero-energy Majorana bound states in superconductors have been proposed to be potential building blocks of a topological quantum computer, because quantum information can be encoded nonlocally in the fermion occupation of a pair of spatially separated Majorana bound states. However, despite intensive efforts, nonlocal signatures of Majorana bound states have not been found in charge transport. In this work, we predict a striking nonlocal phase-coherent electron transfer process by virtue of tunneling in and out of a pair of Majorana bound states. This teleportation phenomenon only exists in a mesoscopic superconductor because of an all-important but previously overlooked charging energy. We propose an experimental setup to detect this phenomenon in a superconductor-quantum-spin-Hall-insulator-magnetic-insulator hybrid system. PMID:20366777

  10. Bound-state beta decay of highly ionized atoms

    SciTech Connect

    Takahashi, K.; Boyd, R.N.; Mathews, G.J.; Yokoi, K.

    1987-10-01

    Nuclear ..beta.. decays of highly ionized atoms under laboratory conditions are studied. Theoretical predictions of ..beta..-decay rates are given for a few cases in which bound-state ..beta.. decay produces particularly interesting effects. A possible storage-ring experiment is proposed for measuring bound-state ..beta..-decay rates, which will be most easily applied to the decay of /sup 3/H/sup +/. .AE

  11. Topological phases for bound states moving in a finite volume

    SciTech Connect

    Bour, Shahin; Koenig, Sebastian; Hammer, H.-W.; Lee, Dean; Meissner, Ulf-G.

    2011-11-01

    We show that bound states moving in a finite periodic volume have an energy correction which is topological in origin and universal in character. The topological volume corrections contain information about the number and mass of the constituents of the bound states. These results have broad applications to lattice calculations involving nucleons, nuclei, hadronic molecules, and cold atoms. We illustrate and verify the analytical results with several numerical lattice calculations.

  12. Sturmian function approach and {bar N}N bound states

    SciTech Connect

    Yan, Y.; Tegen, R.; Gutsche, T.; Faessler, A.

    1997-09-01

    A suitable numerical approach based on Sturmian functions is employed to solve the {bar N}N bound state problem for local and nonlocal potentials. The approach accounts for both the strong short-range nuclear potential and the long-range Coulomb force and provides directly the wave function of protonium and {bar N}N deep bound states with complex eigenvalues E=E{sub R}{minus}i({Gamma}/2). The spectrum of {bar N}N bound states has two parts, the atomic states bound by several keV, and the deep bound states which are bound by several hundred MeV. The observed very small hyperfine splitting of the 1s level and the 1s and 2p decay widths are reasonably well reproduced by both the Paris and Bonn potentials (supplemented with a microscopically derived quark annihilation potential), although there are differences in magnitude and level ordering. We present further arguments for the identification of the {sup 13}PF{sub 2} deep bound state with the exotic tensor meson f{sub 2}(1520). Both investigated models can accommodate the f{sub 2}(1520) but differ greatly in the total number of levels and in their ordering. The model based on the Paris potential predicts the {sup 13}P{sub 0} level slightly below 1.1 GeV while the model based on the Bonn potential puts this state below 0.8 GeV. It remains to be seen if this state can be identified with a scalar partner of the f{sub 2}(1520). {copyright} {ital 1997} {ital The American Physical Society}

  13. Floquet bound states around defects and adatoms in graphene

    NASA Astrophysics Data System (ADS)

    Lovey, D. A.; Usaj, Gonzalo; Foa Torres, L. E. F.; Balseiro, C. A.

    2016-06-01

    Recent studies have focused on laser-induced gaps in graphene which have been shown to have a topological origin, thereby hosting robust states at the sample edges. While the focus has remained mainly on these topological chiral edge states, the Floquet bound states around defects lack a detailed study. In this paper we present such a study covering large defects of different shape and also vacancy-like defects and adatoms at the dynamical gap at ℏ Ω /2 (ℏ Ω being the photon energy). Our results, based on analytical calculations as well as numerics for full tight-binding models, show that the bound states are chiral and appear in a number which grows with the defect size. Furthermore, while the bound states exist regardless of the type of the defect's edge termination (zigzag, armchair, mixed), the spectrum is strongly dependent on it. In the case of top adatoms, the bound state quasienergies depend on the adatoms energy. The appearance of such bound states might open the door to the presence of topological effects on the bulk transport properties of dirty graphene.

  14. Bound States of a Ferromagnetic Wire in a Superconductor

    NASA Astrophysics Data System (ADS)

    Sau, Jay D.; Brydon, P. M. R.

    2015-09-01

    We consider the problem of bound states in strongly anisotropic ferromagnetic impurities in a superconductor, motivated by recent experiments that claim to observe Majorana modes at the ends of ferromagnetic wires on a superconducting substrate [S. Nadj-Perge et al., Science 346, 602 (2014)]. Generalizing the successful theory of bound states of spherically symmetric impurities, we consider a wirelike potential using both analytical and numerical approaches. We find that away from the ends of the wire the bound states form bands with pronounced van Hove singularities, giving rise to subgap peaks in the local density of states. For sufficiently strong magnetization of the wire, we show that this process generically produces a sharp peak at zero energy in the local density of states near the ends of the wire. This zero-energy peak has qualitative similarities to the claimed signature of a Majorana mode observed in the aforementioned experiment.

  15. Bound States of a Ferromagnetic Wire in a Superconductor.

    PubMed

    Sau, Jay D; Brydon, P M R

    2015-09-18

    We consider the problem of bound states in strongly anisotropic ferromagnetic impurities in a superconductor, motivated by recent experiments that claim to observe Majorana modes at the ends of ferromagnetic wires on a superconducting substrate [S. Nadj-Perge et al., Science 346, 602 (2014)]. Generalizing the successful theory of bound states of spherically symmetric impurities, we consider a wirelike potential using both analytical and numerical approaches. We find that away from the ends of the wire the bound states form bands with pronounced van Hove singularities, giving rise to subgap peaks in the local density of states. For sufficiently strong magnetization of the wire, we show that this process generically produces a sharp peak at zero energy in the local density of states near the ends of the wire. This zero-energy peak has qualitative similarities to the claimed signature of a Majorana mode observed in the aforementioned experiment. PMID:26431011

  16. Quantum Bound States in a C-C60 System

    NASA Astrophysics Data System (ADS)

    Adam, R. M.; Sofianos, S. A.

    2015-03-01

    We investigate the quantum mechanical system of a carbon "test atom" in the proximity of a C60 molecule, both inside and outside the fullerene "cage". Two sets of bound states are found to exist, a deeply bound set inside the cage and another weakly bound set outside it. Tunnelling between these regions is highly unlikely to happen because of the extreme height and width of the potential barrier. However, we predict that a layer of atoms could be adsorbed onto C60 by forming a quantum mechanical bound state, with the adsorbed atoms being concentrated above the "panels" of the buckyball, consistent with "bucky onions" observed experimentally. Until now analysis of such fullerene systems has been via classical mechanics, but a quantum approach reveals new insights.

  17. Getting State Certification in Your Embedded Math Programs.

    ERIC Educational Resources Information Center

    Eiland, Jodie; Capps, Janet

    This document presents materials that were developed for a presentation explaining how the Gordon Cooper Technology Center in Shawnee, Oklahoma, obtained state certification for the geometry and trigonometry program that is embedded in its residential and commercial construction program and enables its students to receive high school geometry or…

  18. Effects of bound states on dark matter annihilation

    NASA Astrophysics Data System (ADS)

    An, Haipeng; Wise, Mark B.; Zhang, Yue

    2016-06-01

    We study the impact of bound state formation on dark matter annihilation rates in models where dark matter interacts via a light mediator, the dark photon. We derive the general cross section for radiative capture into all possible bound states, and point out its nontrivial dependence on the dark matter velocity and the dark photon mass. For indirect detection, our result shows that dark matter annihilation inside bound states can play an important role in enhancing signal rates over the rate for direct dark matter annihilation with Sommerfeld enhancement. The effects are strongest for large dark gauge coupling and when the dark photon mass is smaller than the typical momentum of dark matter in the Galaxy. As an example, we show that for thermal dark matter the Fermi gamma ray constraint is substantially increased once bound state effects are taken into account. We also find that bound state effects are not important for dark matter annihilation during the freeze-out and recombination epochs.

  19. Is there a {pi}{lambda}N bound state?

    SciTech Connect

    Gal, A.; Garcilazo, H.

    2008-07-01

    We have searched for bound states in the {pi}{lambda}N system by solving the nonrelativistic Faddeev equations, as well as a relativistic version, with input separable {pi}N, {pi}{lambda}, and {lambda}N interactions. A bound-state solution, driven by the {delta}(1232) and the {sigma}(1385) p-wave meson-baryon resonances, was found in the channel (I,J{sup P})=((3/2),2{sup +}), provided the {lambda} laboratory momentum at which the {lambda}N {sup 3}S{sub 1} phase shift becomes negative is larger than p{sub lab}{approx}750-800 MeV/c. Other strange and charmed {pi}BB{sup '} systems that might have bound states of a similar nature are listed.

  20. Probing Majorana Bound States in T-Shaped Junctions

    NASA Astrophysics Data System (ADS)

    Wu, Bin-He; Cheng, Xiao; Wang, Chun-Rui; Gong, Wei-Jiang

    2014-03-01

    We investigate the transport properties of a pair of Majorana bound states in a T-shaped junction, where two normal leads are coupled with an identical Majorana bound state. Both the scattering matrix and the recursive Green function method show that the peak value of the differential conductance (Gpeak) in units of e2/h and the shot noise Fano factor in the zero bias limit (F0), which are measured at the same lead and zero temperature, satisfy a linear relation as F0 = 1 + Gpeak/2, independent of the magnitude or symmetry of the coupling strengths to the leads. Therefore, combined measurements of the differential conductance and shot noise in the T-shaped geometry can serve as a characteristic signature in probing Majorana bound states.

  1. Bound states in gauge theories as the Poincare group representations

    SciTech Connect

    Cherny, A. Yu.; Dorokhov, A. E.; Han, Nguyen Suan; Pervushin, V. N. Shilin, V. I.

    2013-03-15

    The bound-state generating functional is constructed in gauge theories. This construction is based on the Dirac Hamiltonian approach to gauge theories, the Poincare group classification of fields and their nonlocal bound states, and the Markov-Yukawa constraint of irreducibility. The generating functional contains additional anomalous creations of pseudoscalar bound states: para-positronium in QED and mesons inQCDin the two-gamma processes of the type of {gamma} + {gamma} {yields} {pi}{sub 0} +para-positronium. The functional allows us to establish physically clear and transparent relations between the perturbativeQCD to its nonperturbative low-energy model by means of normal ordering and the quark and gluon condensates. In the limit of small current quark masses, the Gell-Mann-Oakes-Renner relation is derived from the Schwinger-Dyson and Bethe-Salpeter equations. The constituent quark masses can be calculated from a self-consistent nonlinear equation.

  2. A brief review on Majorana bound states in topological superconductors

    NASA Astrophysics Data System (ADS)

    Lin, Rui; Wang, Zhi

    2016-07-01

    Topological superconductivity has drawn much attention recently, and most interests are focused on the Majorana bound states existing at the edges of one-dimensional topological superconductors. These Majorana bound states are ideal platform for studying non-Abelian statistics. Meanwhile, they are proposed to be useful in quantum computation. In this review, we introduce the basic concepts and models in this area. We begin from the Kitaev model, which is the most concise model for one-dimensional topological superconductivity. Then, we discuss how to realize this model with spin-orbit coupling in realistic materials. Finally, we show some simple methods to detect the Majorana bound states and study their novel properties with the help of adjacent quantum dots.

  3. Bounding the persistency of the nonlocality of W states

    NASA Astrophysics Data System (ADS)

    Diviánszky, Péter; Trencsényi, Réka; Bene, Erika; Vértesi, Tamás

    2016-04-01

    The nonlocal properties of the W states are investigated under particle loss. By removing all but two particles from an N -qubit W state, the resulting two-qubit state is still entangled. Hence, the W state has high persistency of entanglement. We ask an analogous question regarding the persistency of nonlocality [see N. Brunner and T. Vértesi, Phys. Rev. A 86, 042113 (2012), 10.1103/PhysRevA.86.042113]. Namely, we inquire what is the minimal number of particles that must be removed from the W state so that the resulting state becomes local. We bound this value in function of N qubits by considering Bell nonlocality tests with two alternative settings per site. In particular, we find that this value is between 2 N /5 and N /2 for large N . We also develop a framework to establish bounds for more than two settings per site.

  4. Force-producing ADP state of myosin bound to actin

    PubMed Central

    Wulf, Sarah F.; Ropars, Virginie; Fujita-Becker, Setsuko; Oster, Marco; Hofhaus, Goetz; Trabuco, Leonardo G.; Pylypenko, Olena; Sweeney, H. Lee; Houdusse, Anne M.; Schröder, Rasmus R.

    2016-01-01

    Molecular motors produce force when they interact with their cellular tracks. For myosin motors, the primary force-generating state has MgADP tightly bound, whereas myosin is strongly bound to actin. We have generated an 8-Å cryoEM reconstruction of this state for myosin V and used molecular dynamics flexed fitting for model building. We compare this state to the subsequent state on actin (Rigor). The ADP-bound structure reveals that the actin-binding cleft is closed, even though MgADP is tightly bound. This state is accomplished by a previously unseen conformation of the β-sheet underlying the nucleotide pocket. The transition from the force-generating ADP state to Rigor requires a 9.5° rotation of the myosin lever arm, coupled to a β-sheet rearrangement. Thus, the structure reveals the detailed rearrangements underlying myosin force generation as well as the basis of strain-dependent ADP release that is essential for processive myosins, such as myosin V. PMID:26976594

  5. Force-producing ADP state of myosin bound to actin.

    PubMed

    Wulf, Sarah F; Ropars, Virginie; Fujita-Becker, Setsuko; Oster, Marco; Hofhaus, Goetz; Trabuco, Leonardo G; Pylypenko, Olena; Sweeney, H Lee; Houdusse, Anne M; Schröder, Rasmus R

    2016-03-29

    Molecular motors produce force when they interact with their cellular tracks. For myosin motors, the primary force-generating state has MgADP tightly bound, whereas myosin is strongly bound to actin. We have generated an 8-Å cryoEM reconstruction of this state for myosin V and used molecular dynamics flexed fitting for model building. We compare this state to the subsequent state on actin (Rigor). The ADP-bound structure reveals that the actin-binding cleft is closed, even though MgADP is tightly bound. This state is accomplished by a previously unseen conformation of the β-sheet underlying the nucleotide pocket. The transition from the force-generating ADP state to Rigor requires a 9.5° rotation of the myosin lever arm, coupled to a β-sheet rearrangement. Thus, the structure reveals the detailed rearrangements underlying myosin force generation as well as the basis of strain-dependent ADP release that is essential for processive myosins, such as myosin V. PMID:26976594

  6. Waltzing Volvox/: Orbiting Bound States of Flagellated Multicellular Algae

    NASA Astrophysics Data System (ADS)

    Drescher, K.; Leptos, K.; Pedley, T. J.; Goldstein, R. E.; Ishikawa, T.

    2008-11-01

    The spherical colonial alga Volvox swims by means of flagella on thousands of surface somatic cells. This geometry and its large size makes it a model organism for the fluid dynamics of multicellularity. Remarkably, when two nearby colonies swim close to a solid surface, they are attracted together and can form a stable bound state in which they continuously waltz around each other. A surface-mediated hydrodynamic attraction between colonies combined with the rotational motion of bottom-heavy Volvox are shown to explain the stability and dynamics of the bound state. This phenomenon is suggested to underlie observed clustering of colonies at surfaces.

  7. Dancing Volvox: Hydrodynamic Bound States of Swimming Algae

    NASA Astrophysics Data System (ADS)

    Drescher, Knut; Leptos, Kyriacos C.; Tuval, Idan; Ishikawa, Takuji; Pedley, Timothy J.; Goldstein, Raymond E.

    2009-04-01

    The spherical alga Volvox swims by means of flagella on thousands of surface somatic cells. This geometry and its large size make it a model organism for studying the fluid dynamics of multicellularity. Remarkably, when two nearby Volvox colonies swim close to a solid surface, they attract one another and can form stable bound states in which they “waltz” or “minuet” around each other. A surface-mediated hydrodynamic attraction combined with lubrication forces between spinning, bottom-heavy Volvox explains the formation, stability, and dynamics of the bound states. These phenomena are suggested to underlie observed clustering of Volvox at surfaces.

  8. An Upper Bound of Fully Entangled Fraction of Mixed States

    NASA Astrophysics Data System (ADS)

    Huang, Xiao-Fen; Jing, Nai-Huan; Zhang, Ting-Gui

    2016-06-01

    We study the fully entangled fraction of a quantum state. An upper bound is obtained for arbitrary bipartite system. This upper bound only depends on the Frobenius norm of the state. Supported by the National Natural Science Foundation of China under Grant Nos. 11401032, 11501153, 11271138, and 11531004; the Natural Science Foundation of Hainan Province under Grant Nos. 20151010, 114006 and 20161006; and the Scientific Research Foundation for Colleges of Hainan Province under Grant No. Hnky2015-18 and Simons Foundation under Grant No. 198129

  9. Directional detection of dark matter in universal bound states

    SciTech Connect

    Laha, Ranjan

    2015-10-01

    It has been suggested that several small-scale structure anomalies in CDM cosmology can be solved by strong self-interaction between dark matter particles. It was shown in Ref. [1] that the presence of a near threshold S-wave resonance can make the scattering cross section at nonrelativistic speeds come close to saturating the unitarity bound. This can result in the formation of a stable bound state of two asymmetric dark matter particles (which we call darkonium). Ref. [2] studied the nuclear recoil energy spectrum in dark matter direct detection experiments due to this incident bound state. Here we study the angular recoil spectrum, and show that it is uniquely determined up to normalization by the S-wave scattering length. Observing this angular recoil spectrum in a dark matter directional detection experiment will uniquely determine many of the low-energy properties of dark matter independent of the underlying dark matter microphysics.

  10. Directional detection of dark matter in universal bound states

    SciTech Connect

    Laha, Ranjan

    2015-10-06

    It has been suggested that several small-scale structure anomalies in Λ CDM cosmology can be solved by strong self-interaction between dark matter particles. It was shown in Ref. [1] that the presence of a near threshold S-wave resonance can make the scattering cross section at nonrelativistic speeds come close to saturating the unitarity bound. This can result in the formation of a stable bound state of two asymmetric dark matter particles (which we call darkonium). Ref. [2] studied the nuclear recoil energy spectrum in dark matter direct detection experiments due to this incident bound state. Here we study the angular recoil spectrum, and show that it is uniquely determined up to normalization by the S-wave scattering length. Furthermore, observing this angular recoil spectrum in a dark matter directional detection experiment will uniquely determine many of the low-energy properties of dark matter independent of the underlying dark matter microphysics.

  11. Thermodynamic Lower Bounds of Deviation from Instantaneous Canonical State

    NASA Astrophysics Data System (ADS)

    Monnai, Takaaki

    2016-04-01

    We address the issue of the characterization of the nonequilibrium states for the time-dependent processes of a system interacting with a large reservoir, which is initially prepared in an equilibrium state. During the time evolution, we apply an external force to the system so that the actual density matrix is quantitatively different from the canonical state specified by the time-dependent system Hamiltonian. To express how the external forcing causes the deviation from equilibrium, we give a class of thermodynamic expressions for the lower bounds of the distance between the actual nonequilibrium state and the corresponding canonical state. The lower bounds are thermodynamically expressed only in terms of the strength of the forcing and its consequent entropy production rate.

  12. A search for unexpected bound states in 15B

    NASA Astrophysics Data System (ADS)

    Hoffman, Calem R.

    2014-09-01

    Bound states in 15B are to be populated through the one proton removal reaction from a 16C beam produced at the RCNP EN Course through 18O fragmentation. γ-decays from these states will be identified by an array of Compton-suppressed HPGe Clover detectors (CAGRA). The goals consist of i) identifying any previously unobserved and unexpected bound states in 15B and ii) to assign total angular momenta to known excited states for the first time. At present only two bound states have been observed in 15B, neither with firm spin or parity assignments. The present work to be discussed is aimed at determining whether an excited 3 /2- state, a state with identical spin-parity as the ground state, resides below the neutron separation energy in 15B. Such an excited 3 /2- state is not predicted to appear below the 15B Sn by shell-model calculations using various p- sd interactions. However, a robust systematic, probably related to the s-wave trends found in the single-neutron states in this region, has been observed for neutron-rich N=10 nuclei and it suggests that the state may appear lower in excitation energy than expected. Providing some measure of validation for the N=10 prediction is a similar trend noticed in the energy differences between ground (p)2 neutron states and excited (sd)2 neutron states in the N=8 neutron-rich isotones. In addition to a search for this unexpected state, additional spectroscopic information on 15B will better aid in the understanding of the N=10 isotones when transitioning from 16C into sparsely probed 14Be. Details of the experimental procedures and motivation will be presented and discussed. Bound states in 15B are to be populated through the one proton removal reaction from a 16C beam produced at the RCNP EN Course through 18O fragmentation. γ-decays from these states will be identified by an array of Compton-suppressed HPGe Clover detectors (CAGRA). The goals consist of i) identifying any previously unobserved and unexpected bound

  13. Majorana bound states in a disordered quantum dot chain

    NASA Astrophysics Data System (ADS)

    Zhang, P.; Nori, Franco

    2016-04-01

    We study Majorana bound states in a disordered chain of semiconductor quantum dots proximity-coupled to an s-wave superconductor. By calculating its topological quantum number, based on the scattering-matrix method and a tight-binding model, we can identify the topological property of such an inhomogeneous one-dimensional system. We study the robustness of Majorana bound states against disorder in both the spin-independent terms (including the chemical potential and the regular spin-conserving hopping) and the spin-dependent term, i.e., the spin-flip hopping due to the Rashba spin–orbit coupling. We find that the Majorana bound states are not completely immune to the spin-independent disorder, especially when the latter is strong. Meanwhile, the Majorana bound states are relatively robust against spin-dependent disorder, as long as the spin-flip hopping is of uniform sign (i.e., the varying spin-flip hopping term does not change its sign along the chain). Nevertheless, when the disorder induces sign-flip in spin-flip hopping, the topological-nontopological phase transition takes place in the low-chemical-potential region.

  14. Soliton interaction and bound states in amplified-damped fiber

    NASA Astrophysics Data System (ADS)

    Afanasjev, V. V.; Akhmediev, N.

    1995-10-01

    It is shown that the soliton interaction can be significantly reduced in a system with ultimately stable soliton propagation. Moreover, under the action of strong filtering and nonlinear gain the soliton interaction can change sign from attraction to repulsion and vice versa. The formation of in-phase and out-of-phase bound states is also demonstrated.

  15. Towards flavored bound states beyond rainbows and ladders

    SciTech Connect

    El-Bennich, B.; Rojas, E.; Melo, J. P. B. C. de; Paracha, M. A.

    2014-11-11

    We give a snapshot of recent progress in solving the Dyson-Schwinger equation with a beyond rainbow-ladder ansatz for the dressed quark-gluon vertex which includes ghost contributions. We discuss the motivations for this approach with regard to heavy-flavored bound states and form factors and briefly describe future steps to be taken.

  16. Effective Hamiltonian for bound states in Yukawa theory

    SciTech Connect

    Weber, Axel

    2013-07-15

    A generalization of the Gell-Mann–Low theorem is applied to lowest nontrivial order to determine an effective Hamiltonian for two-fermion states in relativistic Yukawa theory. The consistency of the corresponding effective Schrödinger equation is thoroughly investigated in various aspects, among others the nonrelativistic and one-body limits, and the small-distance or large-momentum regime of the bound state solutions is discussed in detail. -- Highlights: •A generalization of the Gell-Mann–Low theorem is applied to Yukawa theory. •The effective Hamiltonian for two-fermion states is derived to lowest order. •The nonrelativistic and one-body limits are consistent. •The large-momentum behavior of the bound-state solutions is analyzed. •A critical value for the coupling constant is determined.

  17. A Framework for Bounding Nonlocality of State Discrimination

    NASA Astrophysics Data System (ADS)

    Childs, Andrew M.; Leung, Debbie; Mančinska, Laura; Ozols, Maris

    2013-11-01

    We consider the class of protocols that can be implemented by local quantum operations and classical communication (LOCC) between two parties. In particular, we focus on the task of discriminating a known set of quantum states by LOCC. Building on the work in the paper Quantum nonlocality without entanglement (Bennett et al., Phys Rev A 59:1070-1091, 1999), we provide a framework for bounding the amount of nonlocality in a given set of bipartite quantum states in terms of a lower bound on the probability of error in any LOCC discrimination protocol. We apply our framework to an orthonormal product basis known as the domino states and obtain an alternative and simplified proof that quantifies its nonlocality. We generalize this result for similar bases in larger dimensions, as well as the “rotated” domino states, resolving a long-standing open question (Bennett et al., Phys Rev A 59:1070-1091, 1999).

  18. Bound States in the Continuum in double layer structures

    PubMed Central

    Li, LiangSheng; Yin, Hongcheng

    2016-01-01

    We have theoretically investigated the reflectivity spectrums of single- and double-layer photonic crystal slabs and the dielectric multilayer stack. It is shown that light can be perfectly confined in a single-layer photonic crystal slab at a given incident angle by changing the thickness, permittivity or hole radius of the structure. With a tunable double-layer photonic crystal slab, we demonstrate that the occurrence of tunable bound states in the continuum is dependent on the spacing between two slabs. Moreover, by analytically investigating the Drude lossless multilayer stack model, the spacing dependence of bound states in the continuum is characterized as the phase matching condition that illuminates these states can occur at any nonzero incident angles by adjusting the spacing. PMID:27245435

  19. Bound States in the Continuum in double layer structures.

    PubMed

    Li, LiangSheng; Yin, Hongcheng

    2016-01-01

    We have theoretically investigated the reflectivity spectrums of single- and double-layer photonic crystal slabs and the dielectric multilayer stack. It is shown that light can be perfectly confined in a single-layer photonic crystal slab at a given incident angle by changing the thickness, permittivity or hole radius of the structure. With a tunable double-layer photonic crystal slab, we demonstrate that the occurrence of tunable bound states in the continuum is dependent on the spacing between two slabs. Moreover, by analytically investigating the Drude lossless multilayer stack model, the spacing dependence of bound states in the continuum is characterized as the phase matching condition that illuminates these states can occur at any nonzero incident angles by adjusting the spacing. PMID:27245435

  20. Bound States in the Continuum in double layer structures

    NASA Astrophysics Data System (ADS)

    Li, Liangsheng; Yin, Hongcheng

    2016-06-01

    We have theoretically investigated the reflectivity spectrums of single- and double-layer photonic crystal slabs and the dielectric multilayer stack. It is shown that light can be perfectly confined in a single-layer photonic crystal slab at a given incident angle by changing the thickness, permittivity or hole radius of the structure. With a tunable double-layer photonic crystal slab, we demonstrate that the occurrence of tunable bound states in the continuum is dependent on the spacing between two slabs. Moreover, by analytically investigating the Drude lossless multilayer stack model, the spacing dependence of bound states in the continuum is characterized as the phase matching condition that illuminates these states can occur at any nonzero incident angles by adjusting the spacing.

  1. Schwinger functions, light-quark bound states and sigma terms

    NASA Astrophysics Data System (ADS)

    Höll, A.; Maris, P.; Roberts, C. D.; Wright, S. V.

    2006-11-01

    We explore the viability of using solely spacelike information about a Schwinger function to extract properties of bound states. In a concrete example it is not possible to determine properties of states with masses ≳1.2 GeV. Modern Dyson-Schwinger equation methods supply a well-constrained tool that provides access to hadron masses and σ-terms. We report values of the latter for a range of hadrons. Of interest is an analysis relating to a u,d scalar meson, which is compatible with a picture of the lightest 0 as a bound state of a dressed-quark and -antiquark supplemented by a material pion cloud. A constituent-quark σ-term is defined, which affords a means for assessing the flavour-dependence of dynamical chiral symmetry breaking.

  2. Quantum state discrimination bounds for finite sample size

    SciTech Connect

    Audenaert, Koenraad M. R.; Mosonyi, Milan; Verstraete, Frank

    2012-12-15

    In the problem of quantum state discrimination, one has to determine by measurements the state of a quantum system, based on the a priori side information that the true state is one of the two given and completely known states, {rho} or {sigma}. In general, it is not possible to decide the identity of the true state with certainty, and the optimal measurement strategy depends on whether the two possible errors (mistaking {rho} for {sigma}, or the other way around) are treated as of equal importance or not. Results on the quantum Chernoff and Hoeffding bounds and the quantum Stein's lemma show that, if several copies of the system are available then the optimal error probabilities decay exponentially in the number of copies, and the decay rate is given by a certain statistical distance between {rho} and {sigma} (the Chernoff distance, the Hoeffding distances, and the relative entropy, respectively). While these results provide a complete solution to the asymptotic problem, they are not completely satisfying from a practical point of view. Indeed, in realistic scenarios one has access only to finitely many copies of a system, and therefore it is desirable to have bounds on the error probabilities for finite sample size. In this paper we provide finite-size bounds on the so-called Stein errors, the Chernoff errors, the Hoeffding errors, and the mixed error probabilities related to the Chernoff and the Hoeffding errors.

  3. Shooting quasiparticles from Andreev bound states in a superconducting constriction

    SciTech Connect

    Riwar, R.-P.; Houzet, M.; Meyer, J. S.; Nazarov, Y. V.

    2014-12-15

    A few-channel superconducting constriction provides a set of discrete Andreev bound states that may be populated with quasiparticles. Motivated by recent experimental research, we study the processes in an a.c. driven constriction whereby a quasiparticle is promoted to the delocalized states outside the superconducting gap and flies away. We distinguish two processes of this kind. In the process of ionization, a quasiparticle present in the Andreev bound state is transferred to the delocalized states leaving the constriction. The refill process involves two quasiparticles: one flies away while another one appears in the Andreev bound state. We notice an interesting asymmetry of these processes. The electron-like quasiparticles are predominantly emitted to one side of the constriction while the hole-like ones are emitted to the other side. This produces a charge imbalance of accumulated quasiparticles, that is opposite on opposite sides of the junction. The imbalance may be detected with a tunnel contact to a normal metal lead.

  4. Shooting quasiparticles from Andreev bound states in a superconducting constriction

    NASA Astrophysics Data System (ADS)

    Riwar, R.-P.; Houzet, M.; Meyer, J. S.; Nazarov, Y. V.

    2014-12-01

    A few-channel superconducting constriction provides a set of discrete Andreev bound states that may be populated with quasiparticles. Motivated by recent experimental research, we study the processes in an a.c. driven constriction whereby a quasiparticle is promoted to the delocalized states outside the superconducting gap and flies away. We distinguish two processes of this kind. In the process of ionization, a quasiparticle present in the Andreev bound state is transferred to the delocalized states leaving the constriction. The refill process involves two quasiparticles: one flies away while another one appears in the Andreev bound state. We notice an interesting asymmetry of these processes. The electron-like quasiparticles are predominantly emitted to one side of the constriction while the hole-like ones are emitted to the other side. This produces a charge imbalance of accumulated quasiparticles, that is opposite on opposite sides of the junction. The imbalance may be detected with a tunnel contact to a normal metal lead.

  5. Bound states of neutral particles in external electric fields

    NASA Astrophysics Data System (ADS)

    Lin, Qiong-Gui

    2000-02-01

    Neutral fermions of spin 12 with magnetic moment can interact with electromagnetic fields through nonminimal coupling. The Dirac-Pauli equation for such a fermion coupled to a spherically symmetric or central electric field can be reduced to two simultaneous ordinary differential equations by separation of variables in spherical coordinates. For a wide variety of central electric fields, bound-state solutions of critical energy values can be found analytically. The degeneracy of these energy levels turns out to be numerably infinite. This reveals the possibility of condensing infinitely many fermions into a single energy level. For radially constant and radially linear electric fields, the system of ordinary differential equations can be completely solved, and all bound-state solutions are obtained in closed forms. The radially constant field supports scattering solutions as well. For radially linear fields, more energy levels (in addition to the critical one) are infinitely degenerate. The simultaneous presence of central magnetic and electric fields is discussed.

  6. Bound states in coupled guides. II. Three dimensions

    NASA Astrophysics Data System (ADS)

    Linton, C. M.; Ratcliffe, K.

    2004-04-01

    We compute bound-state energies in two three-dimensional coupled waveguides, each obtained from the two-dimensional configuration considered in paper I [J. Math. Phys. 45, 1359-1379 (2004)] by rotating the geometry about a different axis. The first geometry consists of two concentric circular cylindrical waveguides coupled by a finite length gap along the axis of the inner cylinder, and the second is a pair of planar layers coupled laterally by a circular hole. We have also extended the theory for this latter case to include the possibility of multiple circular windows. Both problems are formulated using a mode-matching technique, and in the cylindrical guide case the same residue calculus theory as used in paper I is employed to find the bound-state energies. For the coupled planar layers we proceed differently, computing the zeros of a matrix derived from the matching analysis directly.

  7. Parity lifetime of bound states in a proximitized semiconductor nanowire

    NASA Astrophysics Data System (ADS)

    Higginbotham, A. P.; Albrecht, S. M.; Kiršanskas, G.; Chang, W.; Kuemmeth, F.; Krogstrup, P.; Jespersen, T. S.; Nygård, J.; Flensberg, K.; Marcus, C. M.

    2015-12-01

    Quasiparticle excitations can compromise the performance of superconducting devices, causing high-frequency dissipation, decoherence in Josephson qubits, and braiding errors in proposed Majorana-based topological quantum computers. Quasiparticle dynamics have been studied in detail in metallic superconductors but remain relatively unexplored in semiconductor-superconductor structures, which are now being intensely pursued in the context of topological superconductivity. To this end, we use a system comprising a gate-confined semiconductor nanowire with an epitaxially grown superconductor layer, yielding an isolated, proximitized nanowire segment. We identify bound states in the semiconductor by means of bias spectroscopy, determine the characteristic temperatures and magnetic fields for quasiparticle excitations, and extract a parity lifetime (poisoning time) of the bound state in the semiconductor exceeding 10 ms.

  8. The role of interaction vertices in bound state calculations

    SciTech Connect

    Cetin Savkli; Franz Gross; John Tjon

    2001-02-01

    In recent studies of the one and two-body problem for scalar interactions it was shown that crossed ladder and ''crossed rainbow'' (for the one-body case) exchanges play a crucial role in nonperturbative dynamics. In this letter we use exact analytical and numerical results to show that the contribution of vertex dressings to the two-body bound state mass for scalar QED are canceled by the wavefunction normalization. This proves, for the first time, that the mass of a two-body bound state given by the full theory can be obtained by summing only ladder and crossed ladder diagrams using a bare vertex and a constant dressed mass. We also discuss the implications of the remarkable cancellation between rainbow and crossed rainbow diagrams that is a feature of one-body calculations.

  9. Matrix algorithms for solving (in)homogeneous bound state equations

    PubMed Central

    Blank, M.; Krassnigg, A.

    2011-01-01

    In the functional approach to quantum chromodynamics, the properties of hadronic bound states are accessible via covariant integral equations, e.g. the Bethe–Salpeter equation for mesons. In particular, one has to deal with linear, homogeneous integral equations which, in sophisticated model setups, use numerical representations of the solutions of other integral equations as part of their input. Analogously, inhomogeneous equations can be constructed to obtain off-shell information in addition to bound-state masses and other properties obtained from the covariant analogue to a wave function of the bound state. These can be solved very efficiently using well-known matrix algorithms for eigenvalues (in the homogeneous case) and the solution of linear systems (in the inhomogeneous case). We demonstrate this by solving the homogeneous and inhomogeneous Bethe–Salpeter equations and find, e.g. that for the calculation of the mass spectrum it is as efficient or even advantageous to use the inhomogeneous equation as compared to the homogeneous. This is valuable insight, in particular for the study of baryons in a three-quark setup and more involved systems. PMID:21760640

  10. Analytic continuation as a bridge between continuum and bound states

    NASA Astrophysics Data System (ADS)

    Blokhintsev, Leonid; Savin, Dmitry

    2015-05-01

    The problem of obtaining characteristics of bound nuclear states from continuum states data is discussed. It is shown that the ambiguities due to the existence of phase-equivalent potentials can be resolved by using the analytic properties of scattering amplitudes. The methods of determination of asymptotic normalization coefficients and vertex constants are considered. The asymptotic normalization coefficients for 6Li in the α + d channel are found by analytic continuation of the two-channel effective range expansion. The account of inelastic channels within the effective range approach is discussed.

  11. Two-body bound states & the Bethe-Salpeter equation

    SciTech Connect

    Pichowsky, M.; Kennedy, M.; Strickland, M.

    1995-01-18

    The Bethe-Salpeter formalism is used to study two-body bound states within a scalar theory: two scalar fields interacting via the exchange of a third massless scalar field. The Schwinger-Dyson equation is derived using functional and diagrammatic techniques, and the Bethe-Salpeter equation is obtained in an analogous way, showing it to be a two-particle generalization of the Schwinger-Dyson equation. The authors also present a numerical method for solving the Bethe-Salpeter equation without three-dimensional reduction. The ground and first excited state masses and wavefunctions are computed within the ladder approximation and space-like form factors are calculated.

  12. Positron-molecule bound states and positive ion production

    NASA Technical Reports Server (NTRS)

    Leventhal, M.; Passner, A.; Surko, C. M.

    1990-01-01

    The interaction was studied of low energy positrons with large molecules such as alkanes. These data provide evidencce for the existence of long lived resonances and bound states of positrons with neutral molecules. The formation process and the nature of these resonances are discussed. The positive ions produced when a positron annihilates with an electron in one of these resonances were observed and this positive ion formation process is discussed. A review is presented of the current state of the understanding of these positron-molecule resonances and the resulting positive ion formation. A number of outstanding issues in this area is also discussed.

  13. Directional detection of dark matter in universal bound states

    DOE PAGESBeta

    Laha, Ranjan

    2015-10-06

    It has been suggested that several small-scale structure anomalies in Λ CDM cosmology can be solved by strong self-interaction between dark matter particles. It was shown in Ref. [1] that the presence of a near threshold S-wave resonance can make the scattering cross section at nonrelativistic speeds come close to saturating the unitarity bound. This can result in the formation of a stable bound state of two asymmetric dark matter particles (which we call darkonium). Ref. [2] studied the nuclear recoil energy spectrum in dark matter direct detection experiments due to this incident bound state. Here we study the angularmore » recoil spectrum, and show that it is uniquely determined up to normalization by the S-wave scattering length. Furthermore, observing this angular recoil spectrum in a dark matter directional detection experiment will uniquely determine many of the low-energy properties of dark matter independent of the underlying dark matter microphysics.« less

  14. Directional detection of dark matter in universal bound states

    NASA Astrophysics Data System (ADS)

    Laha, Ranjan

    2015-10-01

    It has been suggested that several small-scale structure anomalies in Λ CDM cosmology can be solved by strong self-interaction between dark matter particles. It was shown by Braaten and Hammer [Phys. Rev. D 88, 063511 (2013), 10.1103/PhysRevD.88.063511] that the presence of a near threshold S-wave resonance can make the scattering cross section at nonrelativistic speeds come close to saturating the unitarity bound. This can result in the formation of a stable bound state of two asymmetric dark matter particles (which we call darkonium). The work of Laha and Braaten [Phys. Rev. D, 89, 103510 (2014), 10.1103/PhysRevD.89.103510] studied the nuclear recoil energy spectrum in dark matter direct detection experiments due to this incident bound state. Here we study the angular recoil spectrum and show that it is uniquely determined up to normalization by the S-wave scattering length. Observing this angular recoil spectrum in a dark matter directional detection experiment will uniquely determine many of the low-energy properties of dark matter independent of the underlying dark matter microphysics.

  15. Quasiclassical asymptotics and coherent states for bounded discrete spectra

    SciTech Connect

    Gorska, K.; Penson, K. A.; Horzela, A.; Blasiak, P.; Duchamp, G. H. E.; Solomon, A. I.

    2010-12-15

    We consider discrete spectra of bound states for nonrelativistic motion in attractive potentials V{sub {sigma}}(x)=-|V{sub 0}| |x|{sup -}{sigma}, 0<{sigma}{<=}2. For these potentials the quasiclassical approximation for n{yields}{infinity} predicts quantized energy levels e{sub {sigma}}(n) of a bounded spectrum varying as e{sub {sigma}}(n){approx}-n{sup -}2{sigma}/(2-{sigma}). We construct collective quantum states using the set of wavefunctions of the discrete spectrum assuming this asymptotic behavior. We give examples of states that are normalizable and satisfy the resolution of unity, using explicit positive functions. These are coherent states in the sense of Klauder and their completeness is achieved via exact solutions of Hausdorff moment problems, obtained by combining Laplace and Mellin transform methods. For {sigma} in the range 0 < {sigma}{<=} 2/3 we present exact implementations of such states for the parametrization {sigma}= 2(k-l)/(3k-l) with k and l positive integers satisfying k>l.

  16. Accurate calculations of bound rovibrational states for argon trimer

    SciTech Connect

    Brandon, Drew; Poirier, Bill

    2014-07-21

    This work presents a comprehensive quantum dynamics calculation of the bound rovibrational eigenstates of argon trimer (Ar{sub 3}), using the ScalIT suite of parallel codes. The Ar{sub 3} rovibrational energy levels are computed to a very high level of accuracy (10{sup −3} cm{sup −1} or better), and up to the highest rotational and vibrational excitations for which bound states exist. For many of these rovibrational states, wavefunctions are also computed. Rare gas clusters such as Ar{sub 3} are interesting because the interatomic interactions manifest through long-range van der Waals forces, rather than through covalent chemical bonding. As a consequence, they exhibit strong Coriolis coupling between the rotational and vibrational degrees of freedom, as well as highly delocalized states, all of which renders accurate quantum dynamical calculation difficult. Moreover, with its (comparatively) deep potential well and heavy masses, Ar{sub 3} is an especially challenging rare gas trimer case. There are a great many rovibrational eigenstates to compute, and a very high density of states. Consequently, very few previous rovibrational state calculations for Ar{sub 3} may be found in the current literature—and only for the lowest-lying rotational excitations.

  17. Accurate calculations of bound rovibrational states for argon trimer.

    PubMed

    Brandon, Drew; Poirier, Bill

    2014-07-21

    This work presents a comprehensive quantum dynamics calculation of the bound rovibrational eigenstates of argon trimer (Ar3), using the ScalIT suite of parallel codes. The Ar3 rovibrational energy levels are computed to a very high level of accuracy (10(-3) cm(-1) or better), and up to the highest rotational and vibrational excitations for which bound states exist. For many of these rovibrational states, wavefunctions are also computed. Rare gas clusters such as Ar3 are interesting because the interatomic interactions manifest through long-range van der Waals forces, rather than through covalent chemical bonding. As a consequence, they exhibit strong Coriolis coupling between the rotational and vibrational degrees of freedom, as well as highly delocalized states, all of which renders accurate quantum dynamical calculation difficult. Moreover, with its (comparatively) deep potential well and heavy masses, Ar3 is an especially challenging rare gas trimer case. There are a great many rovibrational eigenstates to compute, and a very high density of states. Consequently, very few previous rovibrational state calculations for Ar3 may be found in the current literature-and only for the lowest-lying rotational excitations. PMID:25053315

  18. First observation of bound-state. beta. sup minus decay

    SciTech Connect

    Jung, M.; Bosch, F.; Beckert, K.; Eickhoff, H.; Folger, H.; Franzke, B.; Gruber, A.; Kienle, P.; Klepper, O.; Koenig, W.; Kozhuharov, C.; Mann, R.; Moshammer, R.; Nolden, F.; Schaaf, U.; Soff, G.; Spaedtke, P.; Steck, M.; Stoehlker, T.; Suemmerer, K. , D-6100 Darmstadt )

    1992-10-12

    Bound-state {beta}{sup {minus}} decay was observed for the fist time by storing bare {sub 66}{sup 163}Dy{sup 66+} ions in a heavy-ion storage ring. From the number of {sub 67}{sup 163}Ho{sup 66+} daughter ions, measured as a function of the storage time, a half-life of 47{sub {minus}5}{sup +5} d was derived. By comparing this result with reported half-lives for electron capture (EC) from the {ital M}{sub 1} and {ital M}{sub 2} shells of neutral {sub 67}{sup 163}Ho, bounds for both the {ital Q}{sub EC} value of neutral {sub 67}{sup 163}Ho and for the electron-neutrino mass were set.

  19. Pair condensation and bound states in fermionic systems

    SciTech Connect

    Sedrakian, Armen; Clark, John W.

    2006-03-15

    We study the finite temperature-density phase diagram of an attractive fermionic system that supports two-body (dimer) and three-body (trimer) bound states in free space. Using interactions characteristic for nuclear systems, we obtain the critical temperature T{sub c2} for the superfluid phase transition and the limiting temperature T{sub c3} for the extinction of trimers. The phase diagram features a Cooper-pair condensate in the high-density, low-temperature domain which, with decreasing density, crosses over to a Bose condensate of strongly bound dimers. The high-temperature, low-density domain is populated by trimers whose binding energy decreases toward the density-temperature domain occupied by the superfluid and vanishes at a critical temperature T{sub c3}>T{sub c2}.

  20. Two-gluino bound states and heavy quarkonium

    SciTech Connect

    Zuk, J.; Joshi, G.C.; Wignall, J.W.G.

    1983-10-01

    A supersymmetric octet QCD, incorporating interacting gluons and gluinos, is formulated and used to discuss the features of two-gluino bound states. The short-range gluino-gluino potential is calculated and it is assumed that the complete potential, including the color-confining part, has the same form as the quark-antiquark potential but multiplied by the color factor derived for the short-range part. A spin-dependent mass formula based on a quark-antiquark potential of the Martin single-power type is fitted to the known triplet and singlet states of heavy quarkonia and is then used to make predictions of the mass spectra of /sup 3/S, /sup 1/P, and /sup 3/D gluino-gluino bound states. It is found that the relative energy spacings of these states are almost independent of gluino mass m/sub lambda/ for m/sub lambda/> or approx. =5 GeV, the experimental lower limit.

  1. Autodetachment spectroscopy of the aluminum oxide anion dipole bound state

    SciTech Connect

    Mascaritolo, Kyle J.; Gardner, Adrian M.; Heaven, Michael C.

    2015-09-21

    The {sup 1}Σ{sup +}←X{sup 1}Σ{sup +} ground state to dipole bound state (DBS) electronic transition of AlO{sup −} has been studied by means of autodetachment spectroscopy. Vibrational and rotational molecular constants for AlO{sup −} have been determined for both the ground state (υ″ = 0, 1) and the excited DBS (υ′ = 0, 1). These data provide an improved determination of the electron affinity for AlO (2.6110(7) eV) that is consistent with an earlier measurement. The electron binding energy of the DBS was found to be 52 ± 6 cm{sup −1}. Experimental results are compared with the predictions from high level ab initio calculations.

  2. Fundamental Bounds in Measurements for Estimating Quantum States

    NASA Astrophysics Data System (ADS)

    Lim, Hyang-Tag; Ra, Young-Sik; Hong, Kang-Hee; Lee, Seung-Woo; Kim, Yoon-Ho

    2014-07-01

    Quantum measurement unavoidably disturbs the state of a quantum system if any information about the system is extracted. Recently, the concept of reversing quantum measurement has been introduced and has attracted much attention. Numerous efforts have thus been devoted to understanding the fundamental relation of the amount of information obtained by measurement to either state disturbance or reversibility. Here, we experimentally prove the trade-off relations in quantum measurement with respect to both state disturbance and reversibility. By demonstrating the quantitative bound of the trade-off relations, we realize an optimal measurement for estimating quantum systems with minimum disturbance and maximum reversibility. Our results offer fundamental insights on quantum measurement and practical guidelines for implementing various quantum information protocols.

  3. Configuration space Faddeev formalism: Λ + n + n bound state search

    NASA Astrophysics Data System (ADS)

    Suslov, Vladimir; Filikhin, Igor; Vlahovic, Branislav

    2015-04-01

    The HypHI Collaboration has recently reported the evidence for bound state of Λ + n + n system (Phys. Rev. C 88, 041001(R) (2013)). However, the theoretical analysis did not find Λ3n bound state (see, for instance, Phys. Lett. B 736, 93 (2014)). In the present work we will describe our attempt to construct a phenomenological three-body ΛNN force with the spin-isospin dependence that is attractive in the channel T=1, S=1/2. This dependence was tested to reproduce the value of ground state energy for Λ3H hypernuclei. The formalism of the configuration-space Faddeev equations is applied for Λ + n + n and Λ + n + p systems. As Λ + n interaction the s-wave potential simulating model NSC97f is used. This potential reproduces well the hyperon binding energy for Λ3H nuclei (J. Phys. G: 31, 389 (2005)). The details of the model and obtained results will be presented. This work is supported by the NSF (HRD-1345219) and NASA (NNX09AV07A).

  4. Mechanical bound state in the continuum for optomechanical microresonators

    NASA Astrophysics Data System (ADS)

    Chen, Yuan; Shen, Zhen; Xiong, Xiao; Dong, Chun-Hua; Zou, Chang-Ling; Guo, Guang-Can

    2016-06-01

    Clamping loss limits the quality factor of mechanical mode in the optomechanical resonators supported with the supporting stem. Using the mechanical bound state in the continuum (BIC), we have found that the mechanical clamping loss can be avoided. The mechanical quality factor of a microsphere could be achieved up to 108 for a specific radius of the stem, which forms a mechanical BIC with the combination of the symmetry protected mechanism and the single resonance mechanism. Such a mechanism is proved to be universal for different geometries and materials, thus can also be generalized to design high quality mechanical resonators.

  5. Effect of transverse current on Andreev bound state

    SciTech Connect

    Takahashi, Y.; Hashimoto, Y.; Yun, D. H.; Kim, S. W.; Nakamura, T.; Iye, Y.; Katsumoto, S.

    2013-12-04

    In a superconductor-normal-superconductor (SNS) structure, the effect of transverse current across the normal part on the transport through Andreev bound states (ABSs) has been examined. Here a ballistic InAs two-dimensional electron system (2DES) is used as the N-layer to form ABSs. At the same time the 2DES has strong spin-orbit interaction, hence there should emerge the spin-Hall effect associated with the transverse current. We have observed strong reduction of characteristic oscillation in the conductance versus bias voltage, which may be attributed to spin polarization due to the spin-Hall effect.

  6. Quarkonium-nucleus bound states from lattice QCD

    SciTech Connect

    Beane, S.  R.; Chang, E.; Cohen, S.  D.; Detmold, W.; Lin, H. -W.; Orginos, K.; Parreño, A.; Savage, M.  J.

    2015-06-11

    Quarkonium-nucleus systems are composed of two interacting hadronic states without common valence quarks, which interact primarily through multi-gluon exchanges, realizing a color van der Waals force. We present lattice QCD calculations of the interactions of strange and charm quarkonia with light nuclei. Both the strangeonium-nucleus and charmonium-nucleus systems are found to be relatively deeply bound when the masses of the three light quarks are set equal to that of the physical strange quark. Extrapolation of these results to the physical light-quark masses suggests that the binding energy of charmonium to nuclear matter is B < 40 MeV.

  7. Wireless Majorana Bound States: From Magnetic Tunability to Braiding

    NASA Astrophysics Data System (ADS)

    Fatin, Geoffrey L.; Matos-Abiague, Alex; Scharf, Benedikt; Žutić, Igor

    2016-08-01

    We propose a versatile platform to investigate the existence of Majorana bound states (MBSs) and their non-Abelian statistics through braiding. This implementation combines a two-dimensional electron gas formed in a semiconductor quantum well grown on the surface of an s -wave superconductor with a nearby array of magnetic tunnel junctions (MTJs). The underlying magnetic textures produced by MTJs provide highly controllable topological phase transitions to confine and transport MBSs in two dimensions, overcoming the requirement for a network of wires. Obtained scaling relations confirm that various semiconductor quantum well materials are suitable for this proposal.

  8. Signatures of bound-state-assisted nonsequential double ionization

    SciTech Connect

    Sukiasyan, Suren; McDonald, Chris; Van Vlack, Cole; Destefani, Carlos; Fennel, Thomas; Brabec, Thomas; Ivanov, Misha

    2009-07-15

    The time-dependent multiconfiguration Hartree method is optimized for intense laser dynamics and applied to nonsequential double ionization in a two-electron diatomic model molecule with two dimensions per electron. The efficiency of our method brings these calculations from the realm of large scale computation facilities to single processor machines. The resulting two-electron spectrum exhibits pronounced signatures from which the ionic bound states involved in nonsequential double ionization are retrieved with the help of a semiclassical model. A mechanism for the ionization dynamics is suggested.

  9. Bound states on the lattice with partially twisted boundary conditions

    NASA Astrophysics Data System (ADS)

    Agadjanov, D.; Guo, F.-K.; Ríos, G.; Rusetsky, A.

    2015-01-01

    We propose a method to study the nature of exotic hadrons by determining the wave function renormalization constant Z from lattice simulations. It is shown that, instead of studying the volume-dependence of the spectrum, one may investigate the dependence of the spectrum on the twisting angle, imposing twisted boundary conditions on the fermion fields on the lattice. In certain cases, e.g., the case of the DK bound state which is addressed in detail, it is demonstrated that the partial twisting is equivalent to the full twisting up to exponentially small corrections.

  10. Wireless Majorana Bound States: From Magnetic Tunability to Braiding.

    PubMed

    Fatin, Geoffrey L; Matos-Abiague, Alex; Scharf, Benedikt; Žutić, Igor

    2016-08-12

    We propose a versatile platform to investigate the existence of Majorana bound states (MBSs) and their non-Abelian statistics through braiding. This implementation combines a two-dimensional electron gas formed in a semiconductor quantum well grown on the surface of an s-wave superconductor with a nearby array of magnetic tunnel junctions (MTJs). The underlying magnetic textures produced by MTJs provide highly controllable topological phase transitions to confine and transport MBSs in two dimensions, overcoming the requirement for a network of wires. Obtained scaling relations confirm that various semiconductor quantum well materials are suitable for this proposal. PMID:27563991

  11. The quantum probability equation: I. Bound state perturbation theory

    NASA Astrophysics Data System (ADS)

    Milward, Geoffrey C.; Wilkin, Colin

    2000-10-01

    The partial-wave Schrödinger equation with real boundary conditions is recast as an equation for the probability density. When a small additional potential is included, the changes in the bound-state energy eigenvalues are obtained, up to third order in the perturbation, purely in terms of the perturbing potential and the unperturbed probability density. Although the approach is different, our results are equivalent to those derived by Bender (Bender C M 1978 Advanced Mathematical Methods for Scientists and Engineers (New York: McGraw-Hill) p 330). Knowledge of neither the unperturbed energy spectrum nor the wavefunctions of excited states is required. Evaluations of the second-order energy shift are given for some soluble S-wave problems.

  12. Supersymmetric D-brane bound states with B field and higher dimensional instantons on noncommutative geometry

    SciTech Connect

    Ohta, Kazutoshi

    2001-08-15

    We classify supersymmetric D0-Dp bound states with a nonzero B field by considering T dualities of intersecting branes at angles. Especially we find that the D0-D8 system with the B-field preserves 1/16, 1/8, and 3/16 of supercharges if the B field satisfies the '(anti-)self-dual' condition in dimension 8. The D0-branes in this system are described by eight-dimensional instantons on noncommutative R{sup 8}. We also discuss the extended ADHM construction of the eight-dimensional instantons and its deformation by the B-field. The modified ADHM equations admit a sort of the 'fuzzy sphere' [embeddings of SU(2)] solution.

  13. Recreation Embedded State Tuning for Optimal Readiness and Effectiveness (RESTORE)

    NASA Technical Reports Server (NTRS)

    Pope, Alan T.; Prinzel, Lawrence J., III

    2005-01-01

    Physiological self-regulation training is a behavioral medicine intervention that has demonstrated capability to improve psychophysiological coping responses to stressful experiences and to foster optimal behavioral and cognitive performance. Once developed, these psychophysiological skills require regular practice for maintenance. A concomitant benefit of these physiologically monitored practice sessions is the opportunity to track crew psychophysiological responses to the challenges of the practice task in order to detect shifts in adaptability that may foretell performance degradation. Long-duration missions will include crew recreation periods that will afford physiological self-regulation training opportunities. However, to promote adherence to the regimen, the practice experience that occupies their recreation time must be perceived by the crew as engaging and entertaining throughout repeated reinforcement sessions on long-duration missions. NASA biocybernetic technologies and publications have developed a closed-loop concept that involves adjusting or modulating (cybernetic, for governing) a person's task environment based upon a comparison of that person's physiological responses (bio-) with a training or performance criterion. This approach affords the opportunity to deliver physiological self-regulation training in an entertaining and motivating fashion and can also be employed to create a conditioned association between effective performance state and task execution behaviors, while enabling tracking of individuals psychophysiological status over time in the context of an interactive task challenge. This paper describes the aerospace spin-off technologies in this training application area as well as the current spin-back application of the technologies to long-duration missions - the Recreation Embedded State Tuning for Optimal Readiness and Effectiveness (RESTORE) concept. The RESTORE technology is designed to provide a physiological self

  14. Universal bounds on charged states in 2d CFT and 3d gravity

    NASA Astrophysics Data System (ADS)

    Benjamin, Nathan; Dyer, Ethan; Fitzpatrick, A. Liam; Kachru, Shamit

    2016-08-01

    We derive an explicit bound on the dimension of the lightest charged state in two dimensional conformal field theories with a global abelian symmetry. We find that the bound scales with c and provide examples that parametrically saturate this bound. We also prove that any such theory must contain a state with charge-to-mass ratio above a minimal lower bound. We comment on the implications for charged states in three dimensional theories of gravity.

  15. G-factors of hole bound states in spherically symmetric potentials in cubic semiconductors

    NASA Astrophysics Data System (ADS)

    Miserev, Dmitry; Sushkov, Oleg

    2016-03-01

    Holes in cubic semiconductors have effective spin 3/2 and very strong spin orbit interaction. Due to these factors properties of hole bound states are highly unusual. We consider a single hole bound by a spherically symmetric potential, this can be an acceptor or a spherically symmetric quantum dot. Linear response to an external magnetic field is characterized by the bound state Lande g-factor. We calculate analytically g-factors of all bound states.

  16. Creation Dynamics of Bound States in Supercritical Fields

    SciTech Connect

    Krekora, P.; Cooley, K.; Su, Q.; Grobe, R.

    2005-08-12

    Using space-time resolved solutions to relativistic quantum field theory, we analyze the electron-positron creation process from vacuum in the long-time regime in which multiple pairs are produced. We find that for a supercritical potential of finite extension, the time dependence of the production rate of pairs is described by four distinct regimes that have their direct counterparts in the time evolved spatial density of the particles. These regimes include the shape-invariant birth process, an entanglement-induced reduction of interference, a recurrent Pauli suppression of pair production induced by electron-potential scattering, and finally a production halt associated with a population of supercritical and a partial population of subcritical bound states.

  17. Tetraquark bound states in a Bethe-Salpeter approach

    NASA Astrophysics Data System (ADS)

    Heupel, Walter; Eichmann, Gernot; Fischer, Christian S.

    2012-12-01

    We determine the mass of tetraquark bound states from a coupled system of covariant Bethe-Salpeter equations. Similar in spirit to the quark-diquark model of the nucleon, we approximate the full four-body equation for the tetraquark by a coupled set of two-body equations with meson and diquark constituents. These are calculated from their quark and gluon substructure using a phenomenologically well-established quark-gluon interaction. For the lightest scalar tetraquark we find a mass of the order of 400 MeV and a wave function dominated by the pion-pion constituents. Both results are in agreement with a meson molecule picture for the f0 (600). Our results furthermore suggest the presence of a potentially narrow all-charm tetraquark in the mass region 5-6 GeV.

  18. Cooperativity, partially bound states, and enthalpy-entropy compensation.

    PubMed

    Hunter, Christopher A; Tomas, Salvador

    2003-11-01

    Efforts to develop a quantitative understanding of molecular recognition rely on the additivity of individual intermolecular interactions, and cooperativity represents one of the major potential stumbling blocks. A chemical double-mutant cycle has been used to experimentally measure cooperativity between functional group interactions within a complex framework. The interaction between two aromatic groups varies by 0.2 +/- 0.4 kJ mol(-1) in synthetic H-bonded complexes that differ by 8-13 kJ mol(-1) in overall stability. In these systems, the free energies associated with individual intermolecular interactions can therefore be reliably treated in an additive fashion. The results suggest that alternative explanations should be considered for cooperative phenomena observed in other systems, and a rationale based on the population of partially bound states in flexible molecules is proposed to account for the enthalpic chelate effect and enthalpy-entropy compensation. PMID:14652069

  19. Bound states at exceptional points in the continuum

    NASA Astrophysics Data System (ADS)

    Fernández-García, N.; Hernández, E.; Jáuregui, A.; Mondragón, A.

    2014-05-01

    In this work, an example of exceptional points in the continuous spectrum of a Hamiltonian of von Neumann-Wigner type is presented and discussed. Remarkably, these exceptional points are not associated with a double pole in the scattering matrix but with a double pole in the normalization factor of the Jost eigenfunctions normalized to unit flux. At the exceptional points the two unnormalized Jost eigenfunctions are no longer linearly independent but coalesce to give rise to two Jordan cycles of generalized bound state energy eigenfunctions in the continuum and a Jordan block representation of the Hamiltonian. The regular scattering eigenfunction vanishes at the exceptional points and the irregular scattering eigenfunction has a double pole at the exceptional points. The scattering matrix is a regular analytical function of the wave number k for all k real including the exceptional points.

  20. Weakly bound states with spin-isospin symmetry

    NASA Astrophysics Data System (ADS)

    Kievsky, A.; Gattobigio, M.

    2016-03-01

    We discuss weakly bound states of a few-fermion system having spin-isospin symmetry. This corresponds to the nuclear physics case in which the singlet, a0, and triplet, a1, n - p scattering lengths are large with respect to the range of the nuclear interaction. The ratio of the two is about a0/a1 ≈ -4.31. This value defines a plane in which a0 and a1 can be varied up to the unitary limit, 1/a0 = 0 and 1/a1 = 0, maintaining its ratio fixed. Using a spin dependant potential model we estimate the three-nucleon binding energy along that plane. This analysis can be considered an extension of the Efimov plot for three bosons to the case of three 1/2-spin-isospin fermions.

  1. Conformal mapping and bound states in bent waveguides

    SciTech Connect

    Sadurni, E.; Schleich, W. P.

    2010-12-23

    Is it possible to trap a quantum particle in an open geometry? In this work we deal with the boundary value problem of the stationary Schroedinger (or Helmholtz) equation within a waveguide with straight segments and a rectangular bending. The problem can be reduced to a one-dimensional matrix Schroedinger equation using two descriptions: oblique modes and conformal coordinates. We use a corner-corrected WKB formalism to find the energies of the one-dimensional problem. It is shown that the presence of bound states is an effect due to the boundary alone, with no classical counterpart for this geometry. The conformal description proves to be simpler, as the coupling of transversal modes is not essential in this case.

  2. Creation dynamics of bound States in supercritical fields.

    PubMed

    Krekora, P; Cooley, K; Su, Q; Grobe, R

    2005-08-12

    Using space-time resolved solutions to relativistic quantum field theory, we analyze the electron-positron creation process from vacuum in the long-time regime in which multiple pairs are produced. We find that for a supercritical potential of finite extension, the time dependence of the production rate of pairs is described by four distinct regimes that have their direct counterparts in the time evolved spatial density of the particles. These regimes include the shape-invariant birth process, an entanglement-induced reduction of interference, a recurrent Pauli suppression of pair production induced by electron-potential scattering, and finally a production halt associated with a population of supercritical and a partial population of subcritical bound states. PMID:16196767

  3. Continuum-state and bound-state β--decay rates of the neutron

    NASA Astrophysics Data System (ADS)

    Faber, M.; Ivanov, A. N.; Ivanova, V. A.; Marton, J.; Pitschmann, M.; Serebrov, A. P.; Troitskaya, N. I.; Wellenzohn, M.

    2009-09-01

    For the β--decay of the neutron we analyze the continuum-state and bound-state decay modes. We calculate the decay rates, the electron energy spectrum for the continuum-state decay mode, and angular distributions of the decay probabilities for the continuum-state and bound-state decay modes. The theoretical results are obtained for the new value for the axial coupling constant gA=1.2750(9), obtained recently by H. Abele [Prog. Part. Nucl. Phys. 60, 1 (2008)] from the fit of the experimental data on the coefficient of the correlation of the neutron spin and the electron momentum of the electron energy spectrum of the continuum-state decay mode. We take into account the contribution of radiative corrections and the scalar and tensor weak couplings. The calculated angular distributions of the probabilities of the bound-state decay modes of the polarized neutron can be used for the experimental measurements of the bound-state β--decays into the hyperfine states with total angular momentum F=1 and scalar and tensor weak coupling constants.

  4. Bound States of Dipolr Molecules Studied with the Berggren Expnsiion Method

    SciTech Connect

    Fossez, K.; Michel, N.; Nazarewicz, Witold

    2013-01-01

    Bound states of dipole-bound anions are studied by using a nonadiabatic pseudopotential method and the Berggren expansion involving bound states, decaying resonant states, and nonresonant scattering continuum. The method is benchmarked by using the traditional technique of direct integration of coupled-channel equations. A good agreement between the two methods has been found for well-bound states. For weakly bound subthreshold states with binding energies comparable to rotational energies of the anion, the direct integration approach breaks down and the Berggren expansion method becomes the tool of choice.

  5. Probing the Dark Sector with Dark Matter Bound States

    NASA Astrophysics Data System (ADS)

    An, Haipeng; Echenard, Bertrand; Pospelov, Maxim; Zhang, Yue

    2016-04-01

    A model of the dark sector where O (few GeV ) mass dark matter particles χ couple to a lighter dark force mediator V , mV≪mχ, is motivated by the recently discovered mismatch between simulated and observed shapes of galactic halos. Such models, in general, provide a challenge for direct detection efforts and collider searches. We show that for a large range of coupling constants and masses, the production and decay of the bound states of χ , such as 0-+ and 1-- states, ηD and ϒD, is an important search channel. We show that e+e-→ηD+V or ϒD+γ production at B factories for αD>0.1 is sufficiently strong to result in multiple pairs of charged leptons and pions via ηD→2 V →2 (l+l-) and ϒD→3 V →3 (l+l-) (l =e ,μ ,π ). The absence of such final states in the existing searches performed at BABAR and Belle sets new constraints on the parameter space of the model. We also show that a search for multiple bremsstrahlung of dark force mediators, e+e-→χ χ ¯+n V , resulting in missing energy and multiple leptons, will further improve the sensitivity to self-interacting dark matter.

  6. Probing the Dark Sector with Dark Matter Bound States.

    PubMed

    An, Haipeng; Echenard, Bertrand; Pospelov, Maxim; Zhang, Yue

    2016-04-15

    A model of the dark sector where O(few  GeV) mass dark matter particles χ couple to a lighter dark force mediator V, m_{V}≪m_{χ}, is motivated by the recently discovered mismatch between simulated and observed shapes of galactic halos. Such models, in general, provide a challenge for direct detection efforts and collider searches. We show that for a large range of coupling constants and masses, the production and decay of the bound states of χ, such as 0^{-+} and 1^{--} states, η_{D} and ϒ_{D}, is an important search channel. We show that e^{+}e^{-}→η_{D}+V or ϒ_{D}+γ production at B factories for α_{D}>0.1 is sufficiently strong to result in multiple pairs of charged leptons and pions via η_{D}→2V→2(l^{+}l^{-}) and ϒ_{D}→3V→3(l^{+}l^{-}) (l=e,μ,π). The absence of such final states in the existing searches performed at BABAR and Belle sets new constraints on the parameter space of the model. We also show that a search for multiple bremsstrahlung of dark force mediators, e^{+}e^{-}→χχ[over ¯]+nV, resulting in missing energy and multiple leptons, will further improve the sensitivity to self-interacting dark matter. PMID:27127956

  7. Three-nucleon problem: trinucleon bound states and trinucleon interactions

    SciTech Connect

    Friar, J.L.

    1985-01-01

    The assumptions underlying the formulation and solution of the Schroedinger equation for three nucleons in configuration space are reviewed, in conjunction with those qualitative aspects of the two-nucleon problem which are important. The geometrical features of the problem and the crucial role of the angular momentum barrier are developed. The boundary conditions for scattering are discussed qualitatively, and the Faddeev-Noyes equation is motivated. The method of splines and orthogonal collocation are shown to provide convenient techniques for generating numerical solutions. Properties of the many numerical solutions for the bound states and zero-energy scattering states are discussed. The evidence for three-body forces is reviewed, and the results of the recent calculations including such forces are discussed. The importance of electromagnetic interactions in the three-nucleon systems is motivated. Relativistic corrections and meson-exchange currents are discussed in the context of ''rules of scale'', and the pion-exchange currents of nonrelativistic order are derived. The experimental results for trinucleon electromagnetic interactions are reviewed, including recent tritium data. Conclusions are presented. 56 refs., 23 figs.

  8. Andreev bound state at a strongly correlated oxide interface

    NASA Astrophysics Data System (ADS)

    Cheng, Guanglei; Tomczyk, Michelle; Tacla, Alexandre; Daley, Andrew; Lu, Shicheng; Veazey, Josh; Huang, Mengchen; Irvin, Patrick; Ryu, Sangwoo; Lee, Hyungwoo; Eom, Chang-Beom; Pekker, David; Levy, Jeremy

    Strongly correlated electrons at oxide interfaces give rise to a set of novel physics phenomena including superconductivity and magnetism. At the LaAlO3/SrTiO3 (LAO/STO) interface, signatures of strong electron pairing persist even for conditions where superconductivity is suppressed. Meanwhile, an Andreev bound state (ABS) is a single quasiparticle excitation that mediates pair transport in confined superconductor-normal systems. Here we report a transition from pair resonant transport to ABS in sketched single electron transistors at the LAO/STO interface. This transition is consistent with a change of electron-electron interaction from attractive to repulsive, occurring at or near the Lifshitz transition. Such new electronically tunable electron-electron interaction may be useful for quantum simulation and engineering of novel quantum states in oxide materials. We gratefully acknowledge support from AFOSR FA9550-10-1-0524 (JL, CBE), AFOSR FA9550-12-1-0057 (JL, CBE, AD), NSF DMR-1104191 (JL), ONR N00014-15-1-2847 (JL).

  9. Tabulation of the bound-state energies of atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Horbatsch, M.; Hessels, E. A.

    2016-02-01

    We present tables for the bound-state energies for atomic hydrogen. The tabulated energies include the hyperfine structure and thus this work extends the work of Mohr et al. [P. J. Mohr et al., Rev. Mod. Phys. 84, 1527 (2012)], 10.1103/RevModPhys.84.1527, which excludes the hyperfine structure. The tabulation includes corrections of the hyperfine structure due to the anomalous moment of the electron, due to the finite mass of the proton, and due to off-diagonal matrix elements of the hyperfine Hamiltonian. These corrections are treated incorrectly in most other works. Simple formulas valid for all quantum numbers are presented for the hyperfine corrections. The tabulated energies have uncertainties of less than 1 kHz for all states. This accuracy is possible because of the recent precision measurement [R. Pohl et al., Nature (London) 466, 213 (2010)], 10.1038/nature09250 of the proton radius. The effect of this radius on the energy levels is also tabulated and the energies are compared to precision measurements of atomic hydrogen energy intervals.

  10. Lower bound on concurrence for arbitrary-dimensional tripartite quantum states

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Fei, Shao-Ming; Zheng, Zhu-Jun

    2016-06-01

    In this paper, we study the concurrence of arbitrary-dimensional tripartite quantum states. An explicit operational lower bound of concurrence is obtained in terms of the concurrence of substates. A given example shows that our lower bound may improve the well-known existing lower bounds of concurrence. The significance of our result is to get a lower bound when we study the concurrence of arbitrary m⊗ n⊗ l -dimensional tripartite quantum states.

  11. Absorption of Bound States in Hot, Dense Matter

    SciTech Connect

    Sheperd, R; Audebert, P; Chenais-Popovics, C; Geindre, J P; Fajardo, M; Iglesias, C; Moon, S; Rogers, F; Gauthier, J C; Springer, P

    2001-03-06

    Preliminary experiments using a long pulse laser generated X-ray source to back-light a short pulse laser heated thin foil have been performed at the Laboratoire pour l'Utilisation des Lasers Intenses (LULI) at Ecole Polytechnique in France. In this experiment, a 2 J, 300 ps, 532 nm laser was used to create the X-ray back-lighter. The primary diagnostic was a von Hamos spectrograph coupled to a 500 fs X-ray streak camera (TREX-VHS) developed at LLNL. This diagnostic combines high collection efficiency ({approx} 10{sup -4} steradians) with fast temporal response ({approx} 500 fs), allowing resolution of extremely transient spectral variations. The TREX-VHS was used to determine the time history, intensity, and spectral content of the back-lighter. The second diagnostic, Fourier Domain Interferometry (FDI), provides information about the position of the critical density of the target and thus the expansion hydrodynamics, laying the ground work for the plasma characterization. The plasmas were determined to be moderately to strongly coupled, resulting in absorption measurements that provide insight into bound states under such conditions.

  12. Path integral Monte Carlo on a lattice. II. Bound states.

    PubMed

    O'Callaghan, Mark; Miller, Bruce N

    2016-07-01

    The equilibrium properties of a single quantum particle (qp) interacting with a classical gas for a wide range of temperatures that explore the system's behavior in the classical as well as in the quantum regime is investigated. Both the qp and the atoms are restricted to sites on a one-dimensional lattice. A path integral formalism developed within the context of the canonical ensemble is utilized, where the qp is represented by a closed, variable-step random walk on the lattice. Monte Carlo methods are employed to determine the system's properties. To test the usefulness of the path integral formalism, the Metropolis algorithm is employed to determine the equilibrium properties of the qp in the context of a square well potential, forcing the qp to occupy bound states. We consider a one-dimensional square well potential where all atoms on the lattice are occupied with one atom with an on-site potential except for a contiguous set of sites of various lengths centered at the middle of the lattice. Comparison of the potential energy, the energy fluctuations, and the correlation function are made between the results of the Monte Carlo simulations and the numerical calculations. PMID:27575090

  13. Hadron properties from QCD bound-state equations

    NASA Astrophysics Data System (ADS)

    Eichmann, Gernot

    2009-09-01

    This thesis presents an investigation of meson and baryon properties in the framework of covariant bound-state equations based on the Dyson-Schwinger equations of QCD. Pion and rho-meson, diquark, nucleon and delta-baryon masses are obtained as self-consistent solutions of the respective equations for qbar{q}, qq, qqq and q(qq) systems. The common parenthesis is given by a rainbow-ladder truncation in the quark-(anti-)quark channel. It includes an effective quark-gluon coupling as the only phenomenological input and inherent link in the calculation of meson and baryon observables. Results for hadron masses and the pion's and nucleon's static electromagnetic properties as a function of a self-consistently calculated pion mass are presented and compared to lattice results and their chiral extrapolations. The evolution of the nucleon electromagnetic form factors with larger photon momentum is investigated. The impact of further contributions beyond rainbow-ladder, e.g. pionic corrections, and possible future applications are discussed.

  14. Coexistence of bound and virtual-bound states in shallow-core to valence x-ray spectroscopies

    NASA Astrophysics Data System (ADS)

    Sen Gupta, Subhra; Bradley, J. A.; Haverkort, M. W.; Seidler, G. T.; Tanaka, A.; Sawatzky, G. A.

    2011-08-01

    With the example of the non-resonant inelastic x-ray scattering (NIXS) at the O45 edges (5d→5f) of the actinides, we develop the theory for shallow-core to valence excitations, where the multiplet spread is larger than the core-hole attraction, such as if the core and valence orbitals have the same principal quantum number. This involves very strong final state configuration interaction (CI), which manifests itself as huge reductions in the Slater-Condon integrals, needed to explain the spectral shapes within a simple renormalized atomic multiplet theory. But more importantly, this results in a cross-over from bound (excitonic) to virtual-bound excited states with increasing energy, within the same core-valance multiplet structure, and in large differences between the dipole and high-order multipole transitions, as observed in NIXS. While the bound states (often higher multipole allowed) can still be modeled using local cluster-like models, the virtual-bound resonances (often dipole-allowed) cannot be interpreted within such local approaches. This is in stark contrast to the more familiar core-valence transitions between different principal quantum number shells, where all the final excited states almost invariably form bound core-hole excitons and can be modeled using local approaches. The possibility of observing giant multipole resonances for systems with high angular momentum ground states is also predicted. The theory is important to obtain ground state information from core-level x-ray spectroscopies of strongly correlated transition metal, rare-earth, and actinide systems.

  15. Supersymmetry Approaches to the Bound States of the Generalized Woods-Saxon Potential

    NASA Astrophysics Data System (ADS)

    Fakhri, H.; Sadeghi, J.

    Using the associated Jacobi differential equation, we obtain exactly bound states of the generalization of Woods-Saxon potential with the negative energy levels based on the analytic approach. According to the supersymmetry approaches in quantum mechanics, we show that these bound states by four pairs of the first-order differential operators, represent four types of the laddering equations. Two types of these supersymmetry structures, suggest the derivation of algebraic solutions by two different approaches for the bound states.

  16. Problems of bound states in plasmas—physical and chemical picture revisited

    NASA Astrophysics Data System (ADS)

    Ebeling, W.

    2008-12-01

    We discuss several problems of plasma physics which were in the center of interest of the Rostock group and the research activities of Gerd Röpke who was appointed a docent in 1977 by Rostock University. In particular we will consider the problem of bound states and several approaches to treat bound states in dense systems.

  17. Solitons in superfluid (He-3)-A - Bound states on domain walls

    NASA Technical Reports Server (NTRS)

    Ho, T. L.; Fulco, J. R.; Schrieffer, J. R.; Wilczek, F.

    1984-01-01

    The effects of solitons on the spectrum of fermion excitations in superfluid (He-3)-A are investigated. It is found that there is a two-dimensional manifold of bound states with energies within the gap of the bulk superfluid. The bound-state spectrum lacks inversion symmetry parallel to the wall.

  18. Dynamics of F/D networks: the role of bound states

    SciTech Connect

    Sakellariadou, Mairi; Stoica, Horace E-mail: f.stoica@imperial.ac.uk

    2008-08-15

    In a field theory model, we study, via numerical experiments, the role of bound states in the evolution of cosmic superstring networks, being composed by p F strings, q D strings and (p,q) bound states. We find robust evidence for scaling of all three components of the network, independently of initial conditions. The novelty of our numerical approach consists of having control over the initial abundance of bound states. This indeed allows us to identify the effect of bound states on the evolution of the network. We also find an additional energy loss mechanism, resulting in a lower overall string network energy, and thus scaling of the network. This new mechanism consists of the formation of bound states with an increasing length.

  19. Quasi-bound state lifetimes and classical periodic orbits in HOCl

    NASA Astrophysics Data System (ADS)

    Barr, Alex; Na, Kyungsun; Reichl, Linda

    2011-03-01

    We use a discrete variable representation together with reaction matrix theory to calculate the quasi-bound states of a Chlorine atom scattering off a diatomic molecule of Hydrogen and Oxygen. The lifetimes of these quasi-bound states are found to vary over six orders of magnitude in a very small energy window. By examining Husimi distributions for various quasi-bound states we show that the longest-lived quasi- bound states are anchored by an island of stability surrounding a stable periodic orbit in the otherwise chaotic classical phase space. This stable periodic orbit, which corresponds to Chlorine rotating around the HO molecule, is responsible for the very long lifetimes of these quasi-bound states.

  20. Bound entangled states with a private key and their classical counterpart.

    PubMed

    Ozols, Maris; Smith, Graeme; Smolin, John A

    2014-03-21

    Entanglement is a fundamental resource for quantum information processing. In its pure form, it allows quantum teleportation and sharing classical secrets. Realistic quantum states are noisy and their usefulness is only partially understood. Bound-entangled states are central to this question--they have no distillable entanglement, yet sometimes still have a private classical key. We present a construction of bound-entangled states with a private key based on classical probability distributions. From this emerge states possessing a new classical analogue of bound entanglement, distinct from the long-sought bound information. We also find states of smaller dimensions and higher key rates than previously known. Our construction has implications for classical cryptography: we show that existing protocols are insufficient for extracting private key from our distributions due to their "bound-entangled" nature. We propose a simple extension of existing protocols that can extract a key from them. PMID:24702340

  1. Interacting quantum walkers: two-body bosonic and fermionic bound states

    NASA Astrophysics Data System (ADS)

    Krapivsky, P. L.; Luck, J. M.; Mallick, K.

    2015-11-01

    We investigate the dynamics of bound states of two interacting particles, either bosons or fermions, performing a continuous-time quantum walk on a one-dimensional lattice. We consider the situation where the distance between both particles has a hard bound, and the richer situation where the particles are bound by a smooth confining potential. The main emphasis is on the velocity characterizing the ballistic spreading of these bound states, and on the structure of the asymptotic distribution profile of their center-of-mass coordinate. The latter profile generically exhibits many internal fronts.

  2. Bounds on corner entanglement in quantum critical states

    NASA Astrophysics Data System (ADS)

    Bueno, Pablo; Witczak-Krempa, William

    2016-01-01

    The entanglement entropy in many gapless quantum systems receives a contribution from the corners in the entangling surface in 2+1d, which is characterized by a universal function a (θ ) depending on the opening angle θ , and contains pertinent low energy information. For conformal field theories (CFTs), the leading expansion coefficient in the smooth limit θ →π yields the stress tensor two-point function coefficient CT. Little is known about a (θ ) beyond that limit. Here, we show that the next term in the smooth limit expansion contains information beyond the two- and three-point correlators of the stress tensor. We conjecture that it encodes four-point data, making it much richer. Further, we establish strong constraints on this and higher-order smooth-limit coefficients. We also show that a (θ ) is lower-bounded by a nontrivial function multiplied by the central charge CT, e.g., a (π /2 ) ≥(π2ln2 ) CT/6 . This bound for 90-degree corners is nearly saturated by all known results, including recent numerics for the interacting Wilson-Fisher quantum critical points (QCPs). A bound is also given for the Rényi entropies. We illustrate our findings using O(N ) QCPs, free boson and Dirac fermion CFTs, strongly coupled holographic ones, and other models. Exact results are also given for Lifshitz quantum critical points, and for conical singularities in 3+1d.

  3. Dzyaloshinskii-Moriya interaction as an agent to free the bound entangled states

    NASA Astrophysics Data System (ADS)

    Sharma, Kapil K.; Pandey, S. N.

    2016-04-01

    In the present paper, we investigate the efficacy of Dzyaloshinskii-Moriya (DM) interaction to convert the bound entangled states into free entangled states. We consider the tripartite hybrid system as a pair of non interacting two qutrits initially prepared in bound entangled states and one auxiliary qubit. Here, we consider two types of bound entangled states investigated by Horodecki. The auxiliary qubit interacts with any one of the qutrit of the pair through DM interaction. We show that by tuning the probability amplitude of auxiliary qubit and DM interaction strength, one can free the bound entangled states, which can be further distilled. We use the reduction criterion to find the range of the parameters of probability amplitude of auxiliary qubit and DM interaction strength, for which the states are distillable. The realignment criterion and negativity have been used for detection and quantification of entanglement.

  4. Versatile mode-locked fiber laser with switchable operation states of bound solitons.

    PubMed

    Zou, Xin; Qiu, Jifang; Wang, Xiaodong; Ye, Zi; Shi, Jindan; Wu, Jian

    2016-06-01

    Bound states of two solitons are among the typical forms of bound states and can be observed in various operation states of mode-locked fiber lasers. We experimentally investigated bound solitons (BSs) in a passively mode-locked erbium-doped fiber laser based on a semiconductor saturable absorber mirror, whose operation states can be switched among multiple pulses, passively harmonic mode-locking, and "giant pulses" by simply adjusting the in-line polarization controller with the pump power fixed. Up to four pulses, fourth-order harmonic mode-locking (HML), and a "giant pulse" with four BSs were obtained with increasing pump power. Experimental results showed a correlative relationship among those operation states (N pulses/Nth-order HML/"giant pulses" of N bound solitons) at different pump power levels. The birefringence induced by the erbium-doped fiber inside the laser cavity played a vital role in the transitions of those operation states. PMID:27411182

  5. Photon-assisted tunneling through a topological superconductor with Majorana bound states

    SciTech Connect

    Tang, Han-Zhao; Zhang, Ying-Tao; Liu, Jian-Jun

    2015-12-15

    Employing the Keldysh Nonequilibrium Green’s function method, we investigate time-dependent transport through a topological superconductor with Majorana bound states in the presence of a high frequency microwave field. It is found that Majorana bound states driven by photon-assisted tunneling can absorb(emit) photons and the resulting photon-assisted tunneling side band peaks can split the Majorana bound state that then appears at non-zero bias. This splitting breaks from the current opinion that Majorana bound states appear only at zero bias and thus provides a new experimental method for detecting Majorana bound states in the Non-zero-energy mode. We not only demonstrate that the photon-assisted tunneling side band peaks are due to Non-zero-energy Majorana bound states, but also that the height of the photon-assisted tunneling side band peaks is related to the intensity of the microwave field. It is further shown that the time-varying conductance induced by the Majorana bound states shows negative values for a certain period of time, which corresponds to a manifestation of the phase coherent time-varying behavior in mesoscopic systems.

  6. Search for bound states of the eta-meson in light nuclei

    NASA Technical Reports Server (NTRS)

    Chrien, R. E.; Bart, S.; Pile, P.; Sutter, R.; Tsoupas, N.; Funsten, H. O.; Finn, J. M.; Lyndon, C.; Punjabi, V.; Perdrisat, C. F.

    1988-01-01

    A search for nuclear-bound states of the eta meson was carried out. Targets of lithium, carbon, oxygen, and aluminum were placed in a pion(+) beam at 800 MeV/c. A predicted eta bound state in O-15* (E sub x approx. = 540 MeV) with a width of approx. 9 MeV was not observed. A bound state of a size 1/3 of the predicted cross section would have been seen in this experiment at a confidence level of 3sigma (P is greater than 0.9987).

  7. Ensemble-based characterization of unbound and bound states on protein energy landscape

    PubMed Central

    Ruvinsky, Anatoly M; Kirys, Tatsiana; Tuzikov, Alexander V; Vakser, Ilya A

    2013-01-01

    Physicochemical description of numerous cell processes is fundamentally based on the energy landscapes of protein molecules involved. Although the whole energy landscape is difficult to reconstruct, increased attention to particular targets has provided enough structures for mapping functionally important subspaces associated with the unbound and bound protein structures. The subspace mapping produces a discrete representation of the landscape, further called energy spectrum. We compiled and characterized ensembles of bound and unbound conformations of six small proteins and explored their spectra in implicit solvent. First, the analysis of the unbound-to-bound changes points to conformational selection as the binding mechanism for four proteins. Second, results show that bound and unbound spectra often significantly overlap. Moreover, the larger the overlap the smaller the root mean square deviation (RMSD) between the bound and unbound conformational ensembles. Third, the center of the unbound spectrum has a higher energy than the center of the corresponding bound spectrum of the dimeric and multimeric states for most of the proteins. This suggests that the unbound states often have larger entropy than the bound states. Fourth, the exhaustively long minimization, making small intrarotamer adjustments (all-atom RMSD ≤ 0.7 Å), dramatically reduces the distance between the centers of the bound and unbound spectra as well as the spectra extent. It condenses unbound and bound energy levels into a thin layer at the bottom of the energy landscape with the energy spacing that varies between 0.8–4.6 and 3.5–10.5 kcal/mol for the unbound and bound states correspondingly. Finally, the analysis of protein energy fluctuations showed that protein vibrations itself can excite the interstate transitions, including the unbound-to-bound ones. PMID:23526684

  8. Extremal extensions of entanglement witnesses: Finding new bound entangled states

    SciTech Connect

    Sengupta, R.; Arvind

    2011-09-15

    In this paper, we discuss extremal extensions of entanglement witnesses based on Choi's map. The constructions are based on a generalization of the Choi map, from which we construct entanglement witnesses. These extremal extensions are powerful in terms of their capacity to detect entanglement of positive under partial transpose (PPT) entangled states and lead to unearthing of entanglement of new PPT states. We also use the Cholesky-like decomposition to construct entangled states which are revealed by these extremal entanglement witnesses.

  9. Pair creation induced by transitions between electronic and positronic bound states

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Lv, Q. Z.; Li, Y. T.; Grobe, R.; Su, Q.

    2015-05-01

    We study the creation process of electron-positron pairs from the quantum electrodynamical vacuum under very strong electric fields by solving the quantum field theoretical Dirac equation on a space-time grid. We investigate the role of bound-bound state mixing in such a process, which can be studied if the external force can be modeled by a combination of a potential barrier and a potential well. By increasing the magnitude of the two potentials, discrete states that originate from the positive and negative energy continua can become quasidegenerate in the mass gap region (between -mc 2 and mc 2). We show that this bound-bound state mixing is quite different from the usual bound-continuum state mixing where the particles are created until the Pauli exclusion principle inhibits this process. In the case of bound-bound mixing the particle number exhibits a characteristic oscillatory behavior that in principle can last forever. These findings can be modeled by an effective two-state model.

  10. Quark-antiquark bound-state spectroscopy and QCD

    SciTech Connect

    Bloom, E.D.

    1982-11-01

    The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in experiment, the charmonium model, the mass of states, fine structure and hyperfine structure, classification, widths of states, rate and multipolarity of gamma transitions, questions about bottom, leptonic widths and the determination of Q/sub b/, the mass splitting of the n/sup 3/S/sub 1/ states, the center of gravity of the masses of the n/sup 3/P; states, n/sup 3/ P; fine structure and classification, branching ratios for upsilon' ..-->.. tau chi/sub 6j/ and the tau cascade reactions, hyperfine splitting, and top. (GHT)

  11. Comment on ``Spectroscopic factors for bound s-wave states derived from neutron scattering lengths''

    NASA Astrophysics Data System (ADS)

    Barker, F. C.

    1997-12-01

    The procedure proposed by Mohr et al. [Phys. Rev. C 55, 1591 (1997)] for extracting the spectroscopic factor for a bound s-wave neutron state from the scattering length appears to be of doubtful validity and accuracy.

  12. Upper bounds on the error probabilities and asymptotic error exponents in quantum multiple state discrimination

    SciTech Connect

    Audenaert, Koenraad M. R.; Mosonyi, Milán

    2014-10-01

    We consider the multiple hypothesis testing problem for symmetric quantum state discrimination between r given states σ₁, …, σ{sub r}. By splitting up the overall test into multiple binary tests in various ways we obtain a number of upper bounds on the optimal error probability in terms of the binary error probabilities. These upper bounds allow us to deduce various bounds on the asymptotic error rate, for which it has been hypothesized that it is given by the multi-hypothesis quantum Chernoff bound (or Chernoff divergence) C(σ₁, …, σ{sub r}), as recently introduced by Nussbaum and Szkoła in analogy with Salikhov's classical multi-hypothesis Chernoff bound. This quantity is defined as the minimum of the pairwise binary Chernoff divergences min{sub jstates the bound is actually achieved. It was known to be achieved, in particular, when the state pair that is closest together in Chernoff divergence is more than 6 times closer than the next closest pair. Our results improve on this in two ways. First, we show that the optimal asymptotic rate must lie between C/2 and C. Second, we show that the Chernoff bound is already achieved when the closest state pair is more than 2 times closer than the next closest pair. We also show that the Chernoff bound is achieved when at least r - 2 of the states are pure, improving on a previous result by Nussbaum and Szkoła. Finally, we indicate a number of potential pathways along which a proof (or disproof) may eventually be found that the multi-hypothesis quantum Chernoff bound is always achieved.

  13. Examination of quantized multiskyrmions as possible nuclear bound states of antikaons

    SciTech Connect

    Kopeliovich, Vladimir; Potashnikova, Irina

    2011-06-15

    The spectrum of strange multibaryons (baryon number B=2 and 3) is considered within the chiral soliton model using one of several possible SU(3) quantization models (the bound state rigid oscillator version). The states with energy below that of an antikaon and its corresponding nucleus can be interpreted as antikaon-nucleus bound states. In the formal limit of small kaon mass the number of such states becomes large, and for a real value of this mass there are at least several states with positive and negative parity in the energy gap of one kaon mass. For large values of binding energies the interpretation of such states as just antikaon-nuclear bound states becomes more ambiguous.

  14. Strongly bound metastable states of B2 + 2

    NASA Astrophysics Data System (ADS)

    Bruna, Pablo J.; Wright, James S.

    1990-08-01

    The stabilities of about 25 electronic states of B2+2 have been investigated using a multireference CI (MRD-CI) method and an AO basis set composed of 6s4p2d contracted Gaussian species per atom, including semidiffuse functions relevant for an adequate description of charge transfer interactions. The ground state X1∑+g (σ2gσ2u) is repulsive, as expected by its electronic configuration with a zero bond order. In spite of this and the doubly-positive charge, many excited states are found to be metastable, four of them (11∏g, 11∏u, 13∑-g, and 11Δg ) having potential wells from 1.52 eV (11∏u) to 2.83 eV (13∑-g). Relative to the ground state configuration, the metastable states arise from the excitations σu→σg(3∑+u), σu→πu(3,1∏g), σ2u→σgπu(3,1∏u), and σ2u→π2u(3∑-g, 1Δg, 1∑+g); they are analogous to those states showing deep local minima in B2 and B+2. Differences in stabilities among quasibound states can be explained on the basis of the asymptotic ΔE's between repulsive channels B++B+ and appropriate higher-lying limits (states) B+B2+ of bonding character; another important factor governing stability is the actual bonding character of the electronic configurations assigned to each state. The vertical double-ionization potential B2→B2+2(π2u→∞) between both ground states is 27.97 eV, the repulsive X1∑+g dication state being created with 8.37 eV excess energy relative to B++B+. Doubly-ionized states with a chance of being detected because of their long lifetimes against predissociation are those showing a strongly quasibound character, such as (with the vertical double ionization potential in eV given in parentheses): 11∏g(σuπu→∞; 30.29); 11∏u(σ2uπu→σg∞; 31.30); 13∑-g(σ2u→∞; 31.33), and 11Δg(σ2u→∞; 31.95).

  15. Two-polariton bound states in the Jaynes-Cummings-Hubbard model

    SciTech Connect

    Wong, Max T. C.; Law, C. K.

    2011-05-15

    We examine the eigenstates of the one-dimensional Jaynes-Cummings-Hubbard model in the two-excitation subspace. We discover that two-excitation bound states emerge when the ratio of vacuum Rabi frequency to the tunneling rate between cavities exceeds a critical value. We determine the critical value as a function of the quasimomentum quantum number, and indicate that the bound states carry a strong correlation in which the two polaritons appear to be spatially confined together.

  16. Bound-state fiber laser mode-locked by a graphene-nanotube saturable absorber

    NASA Astrophysics Data System (ADS)

    Yang, H. R.; Chen, G. W.; Kong, Y. C.; Li, W. L.

    2015-02-01

    We have experimentally observed the multiple bound states in a linear-cavity fiber laser mode-locked by a mixture of graphene and single-walled carbon nanotubes. The proposed laser can deliver the fundamental frequency soliton as well as the two and three bound-state solitons at suitable conditions. The numerical simulations confirm the experimental observations. Both the theoretical predictions and experimental results reveal that the spectral filtering effect plays a key role on the lasers.

  17. Quantum Bocce: Magnon-magnon collisions between propagating and bound states in 1D spin chains

    NASA Astrophysics Data System (ADS)

    Longo, Paolo; Greentree, Andrew D.; Busch, Kurt; Cole, Jared H.

    2013-08-01

    The dynamics of two magnons in a Heisenberg spin chain under the influence of a non-uniform magnetic field is investigated by means of a numerical wave-function-based approach using a Holstein-Primakoff transformation. The magnetic field is localized in space such that it supports exactly one single-particle bound state. We study the interaction of this bound mode with an incoming spin wave and the interplay between transmittance, energy and momentum matching. We find analytic criteria for maximizing the interconversion between propagating single-magnon modes and true propagating two-magnon states. The manipulation of bound and propagating magnons is an essential step towards quantum magnonics.

  18. Structural Characterization of Two Metastable ATP-Bound States of P-Glycoprotein

    PubMed Central

    O’Mara, Megan L.; Mark, Alan E.

    2014-01-01

    ATP Binding Cassette (ABC) transporters couple the binding and hydrolysis of ATP to the transport of substrate molecules across the membrane. The mechanism by which ATP binding and/or hydrolysis drives the conformational changes associated with substrate transport has not yet been characterized fully. Here, changes in the conformation of the ABC export protein P-glycoprotein on ATP binding are examined in a series of molecular dynamics simulations. When one molecule of ATP is placed at the ATP binding site associated with each of the two nucleotide binding domains (NBDs), the membrane-embedded P-glycoprotein crystal structure adopts two distinct metastable conformations. In one, each ATP molecule interacts primarily with the Walker A motif of the corresponding NBD. In the other, the ATP molecules interacts with both Walker A motif of one NBD and the Signature motif of the opposite NBD inducing the partial dimerization of the NBDs. This interaction is more extensive in one of the two ATP binding site, leading to an asymmetric structure. The overall conformation of the transmembrane domains is not altered in either of these metastable states, indicating that the conformational changes associated with ATP binding observed in the simulations in the absence of substrate do not lead to the outward-facing conformation and thus would be insufficient in themselves to drive transport. Nevertheless, the metastable intermediate ATP-bound conformations observed are compatible with a wide range of experimental cross-linking data demonstrating the simulations do capture physiologically important conformations. Analysis of the interaction between ATP and its cofactor Mg2+ with each NBD indicates that the coordination of ATP and Mg2+ differs between the two NBDs. The role structural asymmetry may play in ATP binding and hydrolysis is discussed. Furthermore, we demonstrate that our results are not heavily influenced by the crystal structure chosen for initiation of the simulations

  19. Quantum Transport through a Triple Quantum Dot System in the Presence of Majorana Bound States

    NASA Astrophysics Data System (ADS)

    Jiang, Zhao-Tan; Cao, Zhi-Yuan; Zhong, Cheng-Cheng

    2016-05-01

    We study the electron transport through a special quantum-dot (QD) structure composed of three QDs and two Majorana bound states (MBSs) using the nonequilibrium Green's function technique. This QD-MBS ring structure includes two channels with the two coupled MBSs being Channel 1 and one QD being Channel 2, and three types of transport processes such as the electron transmission (ET), the Andreev reflection (AR), and the crossed Andreev reflection (CAR). By comparing the ET, AR, and CAR processes through Channels 1 and 2, we make a systematic study on the transport properties of the QD-MBS ring. It is shown that there appear two kinds of characteristic transport patterns for Channels 1 and 2, as well as the interplay between the two patterns. Of particular interest is that there exists an AR-assisted ET process in Channel 2, which is different from that in Channel 1. Thus a clear “X” pattern due to the ET and AR processes appears in the ET, AR, and CAR transmission coefficients. Moreover, we study how Channel 2 affects the three transport processes when Channel 1 is tuned in the ET and CAR regimes. It is shown that the transport properties of the ET, AR and CAR processes can be adjusted by tuning the energy level of the QD embedded in Channel 2. We believe this research should be a helpful reference for understanding the transport properties in the QD-MBS coupled systems. Supported by National Natural Science Foundation of China under Grant No. 11274040, and by the Program for New Century Excellent Talents in University under Grant No. NCET-08-0044

  20. Zero-energy bound states in a nodal topological lattice

    NASA Astrophysics Data System (ADS)

    Lee, Soo-Yong; Han, Jung Hoon

    2015-06-01

    A nodal topological lattice is a form of magnetic crystal with topologically nontrivial spin texture, which further exhibits a periodic array of nodes with vanishing magnetization. An electronic structure for conduction electrons strongly Hund coupled to such a nodal topological lattice is examined. Our analysis shows that each node attracts two localized states which form narrow bands through internode hybridization within the mid-gap region. Nodal bands carry a Chern number under suitable perturbations, suggesting their potential role in the topological Hall effect. Enhancement of the density of states near zero energy observable in a tunneling experiment will provide a signature of the formation of a nodal topological lattice.

  1. Bound-state quark and gluon contributions to structure functions in QCD

    SciTech Connect

    Brodsky, S.J.

    1990-08-01

    One can distinguish two types of contributions to the quark and gluon structure functions of hadrons in quantum chromodynamics: intrinsic'' contributions, which are due to the direct scattering on the bound-state constituents, and extrinsic'' contributions, which are derived from particles created in the collision. In this talk, I discussed several aspects of deep inelastic structure functions in which the bound-state structure of the proton plays a crucial role: the properties of the intrinsic gluon distribution associated with the proton bound-state wavefunction; the separation of the quark structure function of the proton onto intrinsic bound-valence'' and extrinsic non-valence'' components which takes into account the Pauli principle; the properties and identification of intrinsic heavy quark structure functions; and a theory of shadowing and anti-shadowing of nuclear structure functions, directly related to quark-nucleon interactions and the gluon saturation phenomenon. 49 refs., 5 figs.

  2. Multichannel quantum defect theory of strontium bound Rydberg states

    NASA Astrophysics Data System (ADS)

    Vaillant, C. L.; Jones, M. P. A.; Potvliege, R. M.

    2014-08-01

    Using the reactance matrix approach, we systematically develop new multichannel quantum defect theory (MQDT) models for the singlet and triplet S, P, D and F states of strontium below the first ionization limit, based on improved energy level measurements. The new models reveal additional insights into the character of doubly excited perturber states, and the improved energy level measurements for certain series allow fine structure to be resolved for those series’ perturbers. Comparison between the predictions of the new models and those of previous empirical and ab initio studies reveals good agreement with most series; however, some discrepancies are highlighted. Using the MQDT wave functions derived from our models we calculate other observables such as Landé {{g}J}-factors and radiative lifetimes. The analysis reveals the impact of perturbers on the Rydberg state properties of divalent atoms, highlighting the importance of including two-electron effects in the calculations of these properties. The work enables future investigations of properties such as Stark maps and long-range interactions of Rydberg states of strontium.

  3. Fano effect in an AB interferometer with a quantum dot side-coupled to a single Majorana bound state

    NASA Astrophysics Data System (ADS)

    Zeng, Qi-Bo; Chen, Shu; Lü, Rong

    2016-02-01

    We study the conductance and interference effects through an AB interferometer with an embedded quantum dot (QD) side-coupled to a single Majorana bound state (MBS) by using non-equilibrium Green's function method. The energy levels appearing in the QD are calculated by diagonalizing the Hamiltonian of the embedded QD-MBS system. When the single QD energy level ɛ0 is set to 0, there are three discrete energy levels in the QD appearing at around ω = 0, ±√{ ɛM2 + 2λ2 } due to the coupling with MBS where ɛM is the coupling strength between the two MBSs at the two ends of the nanowire and λ is the coupling strength between the MBS and the QD. Asymmetric Fano lineshapes are found around these levels in the conductance due to the interference between electrons traversing through different paths. The phase shift of electrons through the QD changes from π / 2 to - π / 2 at each of these three energy values. However, the phase does not vary smoothly between these three energy levels but shows severe changes from - π / 2 to π / 2 at ω = ±√{ ɛM2 +λ2 }. As a comparison, we also study the similar AB interferometer in which the QD-MBS system is replaced by a normal QD-QD system or a simple single QD system, which shows only two or one Fano peak and the phase shifts from π / 2 to - π / 2 only at the Fano peaks. These differences reflect the distinct influences of Majorana bound state on the transport properties of AB interferometer.

  4. Bound state eigenfunctions need to vanish faster than | x{| }^{-3/2}

    NASA Astrophysics Data System (ADS)

    Ahmed, Zafar

    2016-07-01

    In quantum mechanics, students are taught to practice that the eigenfunction of a physical bound state must be continuous and vanishing asymptotically so that it is normalizable in x\\in (-∞ ,∞ ). Here we caution that such states may also give rise to infinite uncertainty in the position ({{Δ }}x=∞ ), whereas {{Δ }}p remains finite. Such states may be called loosely bound and spatially extended states, and may be avoided by an additional condition that the eigenfunction vanishes asymptotically faster than | x{| }-3/2.

  5. Bethe-Salpeter bound-state structure in Minkowski space

    NASA Astrophysics Data System (ADS)

    Gutierrez, C.; Gigante, V.; Frederico, T.; Salmè, G.; Viviani, M.; Tomio, Lauro

    2016-08-01

    The quantitative investigation of the scalar Bethe-Salpeter equation in Minkowski space, within the ladder-approximation framework, is extended to include the excited states. This study has been carried out for an interacting system composed by two massive bosons exchanging a massive scalar, by adopting (i) the Nakanishi integral representation of the Bethe-Salpeter amplitude, and (ii) the formally exact projection onto the null plane. Our analysis, on one hand, confirms the reliability of the method already applied to the ground state and, on the other one, extends the investigation from the valence distribution in momentum space to the corresponding quantity in the impact-parameter space, pointing out some relevant features, like (i) the equivalence between Minkowski and Euclidean transverse-momentum amplitudes, and (ii) the leading exponential fall-off of the valence wave function in the impact-parameter space.

  6. Ultrafast excited-state deactivation of flavins bound to dodecin.

    PubMed

    Staudt, Heike; Oesterhelt, Dieter; Grininger, Martin; Wachtveitl, Josef

    2012-05-18

    Dodecins, a group of flavin-binding proteins with a dodecameric quaternary structure, are able to incorporate two flavins within each of their six identical binding pockets building an aromatic tetrade with two tryptophan residues. Dodecin from the archaeal Halobacterium salinarum is a riboflavin storage device. We demonstrate that unwanted side reactions induced by reactive riboflavin species and degradation of riboflavin are avoided by ultrafast depopulation of the reactive excited state of riboflavin. Intriguingly, in this process, the staggered riboflavin dimers do not interact in ground and photoexcited states. Rather, within the tetrade assembly, each riboflavin is kept under the control of the respective adjacent tryptophan, which suggests that the stacked arrangement is a matter of optimizing the flavin load. We further identify an electron transfer in combination with a proton transfer as a central element of the effective excited state depopulation mechanism. Structural and functional comparisons of the archaeal dodecin with bacterial homologs reveal diverging evolution. Bacterial dodecins bind the flavin FMN instead of riboflavin and exhibit a clearly different binding pocket design with inverse incorporations of flavin dimers. The different adoption of flavin changes photochemical properties, making bacterial dodecin a comparably less efficient quencher of flavins. This supports a functional role different for bacterial and archaeal dodecins. PMID:22451648

  7. Unitary photoassociation: One-step production of ground-state bound molecules

    SciTech Connect

    Kallush, S.; Kosloff, R.

    2008-02-15

    Bound-state molecules can be photoassociated directly from ultracold free-atom pairs by excitation to a purely repulsive electronic state. The process is explained on the basis of quantum unitarity: the initially free-scattering state is transformed by an impulsive light pulse to a deformed superposition which contains bound-state components. For pulse durations which are short compared to the ultracold dynamics, the maximal rate of photoassociation was found to be determined by the initial stationary distribution of scattering states of the atom pairs. The process was simulated for an ultracold gas of {sup 87}Rb with a temperature of T=44 {mu}K and a density of {approx_equal}10{sup 11} cm{sup -3}. Transform-limited pulses maximize the photoassociation, yielding {approx}1 bound molecule per pulse. Coherent control calculated by a local control scheme can increase the photoassociation yield by two orders of magnitude.

  8. D*Ξ N bound state in strange three-body systems

    NASA Astrophysics Data System (ADS)

    Garcilazo, H.; Valcarce, A.

    2016-06-01

    The recent update of the strangeness -2 ESC08c Nijmegen potential incorporating the NAGARA and KISO events predicts a Ξ N bound state, D*, in the S31(I =1 ) channel. We study if the existence of this two-body bound state could give rise to stable three-body systems. For this purpose we solve the bound state problem of three-body systems where the Ξ N state is merged with N 's , Λ 's , Σ 's , or Ξ 's , making use of the most recent updates of the two-body ESC08c Nijmegen potentials. We found that there appear stable states in the Ξ N N and Ξ Ξ N systems, the Ξ Λ N and Ξ Σ N systems being unbound.

  9. Wasted Food, Wasted Energy: The Embedded Energy in Food Waste in the United States

    PubMed Central

    2010-01-01

    This work estimates the energy embedded in wasted food annually in the United States. We calculated the energy intensity of food production from agriculture, transportation, processing, food sales, storage, and preparation for 2007 as 8080 ± 760 trillion BTU. In 1995 approximately 27% of edible food was wasted. Synthesizing these food loss figures with our estimate of energy consumption for different food categories and food production steps, while normalizing for different production volumes, shows that 2030 ± 160 trillion BTU of energy were embedded in wasted food in 2007. The energy embedded in wasted food represents approximately 2% of annual energy consumption in the United States, which is substantial when compared to other energy conservation and production proposals. To improve this analysis, nationwide estimates of food waste and an updated estimate for the energy required to produce food for U.S. consumption would be valuable. PMID:20704248

  10. State analysis requirements database for engineering complex embedded systems

    NASA Technical Reports Server (NTRS)

    Bennett, Matthew B.; Rasmussen, Robert D.; Ingham, Michel D.

    2004-01-01

    It has become clear that spacecraft system complexity is reaching a threshold where customary methods of control are no longer affordable or sufficiently reliable. At the heart of this problem are the conventional approaches to systems and software engineering based on subsystem-level functional decomposition, which fail to scale in the tangled web of interactions typically encountered in complex spacecraft designs. Furthermore, there is a fundamental gap between the requirements on software specified by systems engineers and the implementation of these requirements by software engineers. Software engineers must perform the translation of requirements into software code, hoping to accurately capture the systems engineer's understanding of the system behavior, which is not always explicitly specified. This gap opens up the possibility for misinterpretation of the systems engineer's intent, potentially leading to software errors. This problem is addressed by a systems engineering tool called the State Analysis Database, which provides a tool for capturing system and software requirements in the form of explicit models. This paper describes how requirements for complex aerospace systems can be developed using the State Analysis Database.

  11. Upper bound on singlet fraction of two-qubit mixed entangled states

    NASA Astrophysics Data System (ADS)

    Adhikari, Satyabrata; Kumar, Atul

    2016-07-01

    We demonstrate a new method to achieve the maximum singlet fraction using an entangled mixed two-qubit state as a resource. For this, we establish a tight upper bound on singlet fraction and show that the maximal singlet fraction obtained in Verstraete and Verschelde (Phys Rev Lett 90:097901(1)-097901(4), 2003) does not attain the upper bound on the singlet fraction derived here. Interestingly, we found that the required upper bound can, in fact, be achieved using local filtering operations.

  12. Invariant criteria for bound states, degree of ionization, and plasma phase transition

    NASA Technical Reports Server (NTRS)

    Girardeau, M. D.

    1990-01-01

    Basis invariant characterizations of bound states and bound fraction of a partially ionized hydrogen plasma are given in terms of properties of the spectrum of eigenvalues and eigenfunctions of the equilibrium quantum statistical one-proton-one-electron reduced density matrix. It is suggested that these can be used to place theories of a proposed plasma-ionization phase transition on a firm foundation. This general approach may be relevant to cosmological questions such as the quark deconfinement-confinement transition.

  13. Fingerprint of topological Andreev bound states in phase-dependent heat transport

    NASA Astrophysics Data System (ADS)

    Sothmann, Björn; Hankiewicz, Ewelina M.

    2016-08-01

    We demonstrate that phase-dependent heat currents through superconductor-topological insulator Josephson junctions provide a useful tool to probe the existence of topological Andreev bound states, even for multichannel surface states. We predict that in the tunneling regime topological Andreev bound states lead to a minimum of the thermal conductance for a phase difference ϕ =π , in clear contrast to a maximum of the thermal conductance at ϕ =π that occurs for trivial Andreev bound states in superconductor-normal-metal tunnel junctions. This opens up the possibility that phase-dependent heat transport can distinguish between topologically trivial and nontrivial 4 π modes. Furthermore, we propose a superconducting quantum interference device geometry where phase-dependent heat currents can be measured using available experimental technology.

  14. Bound states and E8 symmetry effects in perturbed quantum Ising chains

    NASA Astrophysics Data System (ADS)

    Kjall, Jonas; Pollmann, Frank; Moore, Joel

    2011-03-01

    In a recent experiment on CoNb2O6 , Coldea et al. found for the first time experimental evidence of the exceptional Lie algebra E8 . The emergence of this symmetry was theoretically predicted long ago for the transverse quantum Ising chain in the presence of a weak longitudinal field. We consider an accurate microscopic model of CoNb2O6 incorporating additional couplings and calculate numerically the dynamical structure function using a recently developed matrix-product-state method. We compare the signatures of this model to those found in the transverse Ising chain in a longitudinal field and to experimental data, with focus on how far the effects of integrability extends and how robust they are to the additional interactions. The excitation spectra show bound states characteristic of the weakly broken E8 symmetry and a bound state continuum carrying spectral weight comparable to the higher bound states.

  15. Narrow nucleon-ψ (2 S ) bound state and LHCb pentaquarks

    NASA Astrophysics Data System (ADS)

    Eides, Michael I.; Petrov, Victor Yu.; Polyakov, Maxim V.

    2016-03-01

    We interpret the newly discovered pentaquark Pc(4450 ) as a bound state of charmonium ψ (2 S ) and the nucleon. The binding potential is due to the charmonium-nucleon interaction that in the heavy quark approximation is proportional to the product of the charmonium chromoelectric polarizability and the nucleon energy-momentum distribution. We use the large Nc expansion to estimate the quarkonium polarizability and calculate the nucleon properties in the framework of the mean-field picture of light baryons. Two almost degenerate states JP=(1 /2 )- and JP=(3/2) - are predicted at the position of the Pc(4450 ) pentaquark. We find that the nucleon-ψ (2 S ) bound state has a naturally narrow width in the range of tens of MeV. The unitary multiplet partners of the Pc(4450 ) pentaquark and the generalization to b b ¯-nucleon pentaquark bound states are discussed.

  16. R-matrix calculation of bound and resonant states of BeH

    NASA Astrophysics Data System (ADS)

    Chakrabarti, K.; Tennyson, Jonathan

    2014-12-01

    Bound and resonant states of BeH are studied using the diatomic UK molecular R-matrix codes together with a Slater basis set for the BeH+ target states. Bound and resonant states of BeH are determined from an e-BeH+ collisional calculation. The calculations are repeated for 40 internuclear distances in the range 1.5-6.0 a 0 to yield bound state and resonance curves for BeH. Additionally, we also obtain the resonance widths in the range of the inter-nuclear distances considered. The data obtained may be useful for modeling various e-BeH+ collision-induced processes, particularly dissociative recombination and dissociative excitation.

  17. R-matrix calculation of bound and resonant states of BeH

    NASA Astrophysics Data System (ADS)

    Chakrabarti, K.; Tennyson, Jonathan

    2015-12-01

    Bound and resonant states of BeH are studied using the diatomic UK molecular R-matrix codes together with a Slater basis set for the BeH+ target states. Bound and resonant states of BeH are determined from an e-BeH+ collisional calculation. The calculations are repeated for 40 internuclear distances in the range 1.5-6.0 a 0 to yield bound state and resonance curves for BeH. Additionally, we also obtain the resonance widths in the range of the inter-nuclear distances considered. The data obtained may be useful for modeling various e-BeH+ collision-induced processes, particularly dissociative recombination and dissociative excitation.

  18. Tunable Plasmonic Reflection by Bound 1D Electron States in a 2D Dirac Metal.

    PubMed

    Jiang, B-Y; Ni, G X; Pan, C; Fei, Z; Cheng, B; Lau, C N; Bockrath, M; Basov, D N; Fogler, M M

    2016-08-19

    We show that the surface plasmons of a two-dimensional Dirac metal such as graphene can be reflected by linelike perturbations hosting one-dimensional electron states. The reflection originates from a strong enhancement of the local optical conductivity caused by optical transitions involving these bound states. We propose that the bound states can be systematically created, controlled, and liquidated by an ultranarrow electrostatic gate. Using infrared nanoimaging, we obtain experimental evidence for the locally enhanced conductivity of graphene induced by a carbon nanotube gate, which supports this theoretical concept. PMID:27588873

  19. Tunable Plasmonic Reflection by Bound 1D Electron States in a 2D Dirac Metal

    NASA Astrophysics Data System (ADS)

    Jiang, B.-Y.; Ni, G. X.; Pan, C.; Fei, Z.; Cheng, B.; Lau, C. N.; Bockrath, M.; Basov, D. N.; Fogler, M. M.

    2016-08-01

    We show that the surface plasmons of a two-dimensional Dirac metal such as graphene can be reflected by linelike perturbations hosting one-dimensional electron states. The reflection originates from a strong enhancement of the local optical conductivity caused by optical transitions involving these bound states. We propose that the bound states can be systematically created, controlled, and liquidated by an ultranarrow electrostatic gate. Using infrared nanoimaging, we obtain experimental evidence for the locally enhanced conductivity of graphene induced by a carbon nanotube gate, which supports this theoretical concept.

  20. Tunneling spectroscopy of quasiparticle bound states in a spinful Josephson junction.

    PubMed

    Chang, W; Manucharyan, V E; Jespersen, T S; Nygård, J; Marcus, C M

    2013-05-24

    The spectrum of a segment of InAs nanowire, confined between two superconducting leads, was measured as function of gate voltage and superconducting phase difference using a third normal-metal tunnel probe. Subgap resonances for odd electron occupancy-interpreted as bound states involving a confined electron and a quasiparticle from the superconducting leads, reminiscent of Yu-Shiba-Rusinov states-evolve into Kondo-related resonances at higher magnetic fields. An additional zero-bias peak of unknown origin is observed to coexist with the quasiparticle bound states. PMID:23745916

  1. Observation of Dipole-Bound State and High-Resolution Photoelectron Imaging of Cold Acetate Anions

    NASA Astrophysics Data System (ADS)

    Zhu, Guo-Zhu; Huang, Dao-Ling; Wang, Lai-Sheng

    2015-06-01

    We report the observation of a dipole-bound state and a high-resolution photoelectron imaging study of cryogenically cooled acetate anions (CH3COO-). Both high-resolution non-resonant and resonant photoelectron spectra via the dipole-bound state of CH3COO- are obtained. The binding energy of the dipole-bound state relative to the detachment threshold is determined to be 53 ±{8} wn. The electron affinity of the CH_3COObullet neutral radical is measured accurately as 26 236 ±{8} wn (3.2528 ±{ 0.0010} eV) using high-resolution photoelectron imaging. This accurate electron affinity is validated by observation of autodetachment from two vibrational levels of the dipole-bound state of CH3COO-. Excitation spectra to the dipole-bound states yield rotational profiles, allowing the rotational temperature of the trapped CH3COO- anions to be evaluated 1. [1] D. L. Huang, G. Z. Zhu and L. S. Wang, J. Chem. Phys., 2015, 142, 091103

  2. Andreev and Majorana bound states in single and double quantum dot structures.

    PubMed

    Silva, Joelson F; Vernek, E

    2016-11-01

    We present a numerical study of the emergence of Majorana and Andreev bound states in a system composed of two quantum dots, one of which is coupled to a conventional superconductor, SC1, and the other connects to a topological superconductor, SC2. By controlling the interdot coupling we can drive the system from two single (uncoupled) quantum dots to double (coupled) dot system configurations. We employ a recursive Green's function technique that provides us with numerically exact results for the local density of states of the system. We first show that in the uncoupled dot configuration (single dot behavior) the Majorana and the Andreev bound states appear in an individual dot in two completely distinct regimes. Therefore, they cannot coexist in the single quantum dot system. We then study the coexistence of these states in the coupled double dot configuration. In this situation we show that in the trivial phase of SC2, the Andreev states are bound to an individual quantum dot in the atomic regime (weak interdot coupling) or extended over the entire molecule in the molecular regime (strong interdot coupling). More interesting features are actually seen in the topological phase of SC2. In this case, in the atomic limit, the Andreev states appear bound to one of the quantum dots while a Majorana zero mode appears in the other one. In the molecular regime, on the other hand, the Andreev bound states take over the entire molecule while the Majorana state remains always bound to one of the quantum dots. PMID:27602524

  3. Explicit formula for the Holevo bound for two-parameter qubit-state estimation problem

    NASA Astrophysics Data System (ADS)

    Suzuki, Jun

    2016-04-01

    The main contribution of this paper is to derive an explicit expression for the fundamental precision bound, the Holevo bound, for estimating any two-parameter family of qubit mixed-states in terms of quantum versions of Fisher information. The obtained formula depends solely on the symmetric logarithmic derivative (SLD), the right logarithmic derivative (RLD) Fisher information, and a given weight matrix. This result immediately provides necessary and sufficient conditions for the following two important classes of quantum statistical models; the Holevo bound coincides with the SLD Cramér-Rao bound and it does with the RLD Cramér-Rao bound. One of the important results of this paper is that a general model other than these two special cases exhibits an unexpected property: the structure of the Holevo bound changes smoothly when the weight matrix varies. In particular, it always coincides with the RLD Cramér-Rao bound for a certain choice of the weight matrix. Several examples illustrate these findings.

  4. Resonances and bound states of the 't Hooft-Polyakov monopole

    SciTech Connect

    Russell, K. M.; Schroers, B. J.

    2011-03-15

    We present a systematic approach to the linearized Yang-Mills-Higgs equations in the background of a 't Hooft-Polyakov monopole and use it to unify and extend previous studies of their spectral properties. We show that a quaternionic formulation allows for a compact and efficient treatment of the linearized equations in the Bogomol'nyi-Prasad-Sommerfield limit of vanishing Higgs self-coupling and use it to study both scattering and bound states. We focus on the sector of vanishing generalized angular momentum and analyze it numerically, putting zero-energy bound states, Coulomb bound states, and infinitely many Feshbach resonances into a coherent picture. We also consider the linearized Yang-Mills-Higgs equations with nonvanishing Higgs self-coupling and confirm the occurrence of Feshbach resonances in this situation.

  5. Degeneracy of Majorana bound states and fractional Josephson effect in a dirty SNS junction.

    PubMed

    Ikegaya, S; Asano, Y

    2016-09-21

    We theoretically study the stability of more than one Majorana fermion appearing in a p-wave superconductor/dirty normal metal/p-wave superconductor junction in two-dimensions by using the chiral symmetry of a Hamiltonian. At the phase difference across the junction φ being π, we will show that all of the Majorana bound states in the normal metal belong to the same chirality. Due to this pure chiral feature, the Majorana bound states retain their high degree of degeneracy at zero energy even in the presence of a random potential. As a consequence, the resonant transmission of a Cooper pair via the degenerate Majorana bound states carries the Josephson current at [Formula: see text], which explains the fractional current-phase relationship discussed in a number of previous papers. PMID:27420174

  6. Extended supersymmetry for the bound states of the generalized Hulthén potential hierarchy

    NASA Astrophysics Data System (ADS)

    Fakhri, H.; Chenaghlou, A.

    2004-09-01

    Using the associated hypergeometric differential equation, we analytically solve the bound states corresponding to a hierarchy of the radial potential -v0 e-dgrr/(1 - e-dgrr) + c e-dgrr/(1 - e-dgrr)2 as a generalization of the Hulthén potential. Then, an analytic solution corresponding to a special case for which the parameter c is expected to be in terms of l(l + 1) is also derived. Meanwhile without introducing a superpotential and in the framework of supersymmetric quantum mechanics, it is shown that these bound states can be calculated by two different algebraic methods. Based on these two approaches, it is noted that the bound states realize an extended supersymmetry structure.

  7. Degeneracy of Majorana bound states and fractional Josephson effect in a dirty SNS junction

    NASA Astrophysics Data System (ADS)

    Ikegaya, S.; Asano, Y.

    2016-09-01

    We theoretically study the stability of more than one Majorana fermion appearing in a p-wave superconductor/dirty normal metal/p-wave superconductor junction in two-dimensions by using the chiral symmetry of a Hamiltonian. At the phase difference across the junction φ being π, we will show that all of the Majorana bound states in the normal metal belong to the same chirality. Due to this pure chiral feature, the Majorana bound states retain their high degree of degeneracy at zero energy even in the presence of a random potential. As a consequence, the resonant transmission of a Cooper pair via the degenerate Majorana bound states carries the Josephson current at \\varphi =π -{{0}+} , which explains the fractional current-phase relationship discussed in a number of previous papers.

  8. Stationary bound states of massless scalar fields around black holes and black hole analogues

    NASA Astrophysics Data System (ADS)

    Benone, Carolina L.; Crispino, Luís C. B.; Herdeiro, Carlos A. R.; Radu, Eugen

    2015-06-01

    We discuss stationary bound states, a.k.a. clouds, for a massless test scalar field around Kerr black holes (BHs) and spinning acoustic BH analogues. In view of the absence of a mass term, the trapping is achieved via enclosing the BH — scalar field system in a cavity and imposing Dirichlet or Neumann boundary conditions. We discuss the variation of these bounds states with the discrete parameters that label them, as well as their spatial distribution, complementing results in our previous work [C. L. Benone, L. C. B. Crispino, C. Herdeiro and E. Radu, Phys. Rev. D91 (2015) 104038].

  9. The Relativistic Three-Body Bound State in Three-Dimensions

    NASA Astrophysics Data System (ADS)

    Hadizadeh, M. R.; Elster, Ch.; Polyzou, W. N.

    2016-03-01

    Studying of the relativistic three-body bound state in a three-dimensional (3D) approach is a necessary first step in a process to eventually perform scattering calculations at GeV energies, where partial-wave expansions are not useful. To this aim we recently studied relativistic effects in the binding energy and for the first time, obtained the relativistic 3B wave function [1]. The relativistic Faddeev integral equations for the bound state are formulated in terms of momentum vectors, and relativistic invariance is incorporated within the framework of Poincaré invariant quantum mechanics.

  10. Bound States of Spinless Particles in a Short-Range Potential

    NASA Astrophysics Data System (ADS)

    Hassanabadi, Hassan; de Castro, Antonio Soares

    2015-04-01

    With a general mixing of vector and scalar couplings in a two-dimensional world, a short-range potential is used to explore certain features of the bound states of a spinless particle. Bound-state solutions are found in terms of the Gauss hypergeometric series when the potential parameters obey a certain constraint relation limiting the dosage of a vector coupling. The appearance of the Schiff-Snyder-Weinberg effect for a strong vector coupling and a short-range potential as well as its suppression by the addition of a scalar coupling is discussed.

  11. Kinematic constraints on formation of bound states of cosmic strings: Field theoretical approach

    SciTech Connect

    Salmi, P.; Achucarro, A.; Copeland, E. J.; Kibble, T. W. B.; Putter, R. de; Steer, D. A.

    2008-02-15

    Superstring theory predicts the potential formation of string networks with bound states ending in junctions. Kinematic constraints for junction formation have been derived within the Nambu-Goto thin string approximation. Here we test these constraints numerically in the framework of the Abelian-Higgs model in the Type-I regime and report on good agreement with the analytical predictions. We also demonstrate that strings can effectively pass through each other when they meet at speeds slightly above the critical velocity permitting bound-state formation. This is due to reconnection effects that are beyond the scope of the Nambu-Goto approximation.

  12. Light-Cone Distribution Amplitudes for Non-Relativistic Bound States

    SciTech Connect

    Feldmann, Th.; Bell, G.

    2007-11-19

    We calculate light-cone distribution amplitudes for non-relativistic bound states, including radiative corrections from relativistic gluon exchange to first order in the strong coupling constant. Our results apply to hard exclusive reactions with non-relativistic bound states in the QCD factorization approach like, for instance, B{sub c}{yields}{eta}{sub c}l{nu} or e{sup +}e{sup -}{yields}J/{psi}{eta}{sub c}. They also serve as a toy model for light-cone distribution amplitudes of light mesons or heavy B and D mesons.

  13. Bound and Scattering State of Position Dependent Mass Klein-Gordon Equation with Hulthen Plus Deformed-Type Hyperbolic Potential

    NASA Astrophysics Data System (ADS)

    Ikot, A. N.; Obong, H. P.; Abbey, T. M.; Zare, S.; Ghafourian, M.; Hassanabadi, H.

    2016-05-01

    In this article we use supersymmetry quantum mechanics and factorization methods to study the bound and scattering state of Klein-Gordon equation with deformed Hulthen plus deformed hyperbolical potential for arbitrary state in D-dimensions. The analytic relativistic bound state eigenvalues and the scattering phase factor are found in closed form. We report on the numerical results for the bound state energy in D-dimensions.

  14. Embedded Clusters in Molecular Clouds

    NASA Astrophysics Data System (ADS)

    Lada, Charles J.; Lada, Elizabeth A.

    Stellar clusters are born embedded within giant molecular clouds (GMCs) and during their formation and early evolution are often only visible at infrared wavelengths, being heavily obscured by dust. Over the past 15 years advances in infrared detection capabilities have enabled the first systematic studies of embedded clusters in galactic molecular clouds. In this article we review the current state of empirical knowledge concerning these extremely young protocluster systems. From a survey of the literature we compile the first extensive catalog of galactic embedded clusters. We use the catalog to construct the mass function and estimate the birthrate for embedded clusters within 2 kpc of the sun. We find that the embedded cluster birthrate exceeds that of visible open clusters by an order of magnitude or more indicating a high infant mortality rate for protocluster systems. Less than 4-7% of embedded clusters survive emergence from molecular clouds to become bound clusters of Pleiades age. The vast majority (90%) of stars that form in embedded clusters form in rich clusters of 100 or more members with masses in excess of 50 M⊙. Moreover, observations of nearby cloud complexes indicate that embedded clusters account for a significant (70-90%) fraction of all stars formed in GMCs. We review the role of embedded clusters in investigating the nature of the initial mass function (IMF) that, in one nearby example, has been measured over the entire range of stellar and substellar mass, from OB stars to substellar objects near the deuterium burning limit. We also review the role embedded clusters play in the investigation of circumstellar disk evolution and the important constraints they provide for understanding the origin of planetary systems. Finally, we discuss current ideas concerning the origin and dynamical evolution of embedded clusters and the implications for the formation of bound open clusters.

  15. Calculations of K- nuclear quasi-bound states based on chiral meson-baryon amplitudes

    NASA Astrophysics Data System (ADS)

    Gazda, Daniel; Mareš, Jiří

    2012-05-01

    In-medium K¯N scattering amplitudes developed within a new chirally motivated coupled-channel model due to Cieplý and Smejkal that fits the recent SIDDHARTA kaonic hydrogen 1s level shift and width are used to construct K- nuclear potentials for calculations of K- nuclear quasi-bound states. The strong energy and density dependence of scattering amplitudes at and near threshold leads to K- potential depths -Re VK≈80-120 MeV. Self-consistent calculations of all K- nuclear quasi-bound states, including excited states, are reported. Model dependence, polarization effects, the role of p-wave interactions, and two-nucleon K-NN→YN absorption modes are discussed. The K- absorption widths ΓK are comparable or even larger than the corresponding binding energies BK for allK- nuclear quasi-bound states, exceeding considerably the level spacing. This discourages search for K- nuclear quasi-bound states in any but the lightest nuclear systems.

  16. Bound states of two bosons in an optical lattice near an association resonance

    SciTech Connect

    Sanders, Jerome C.; Odong, Otim; Javanainen, Juha; Mackie, Matt

    2011-03-15

    We model two bosons in an optical lattice near a Feshbach or photoassociation resonance, focusing on the Bose-Hubbard model in one dimension. Whereas the usual atoms-only theory with a tunable scattering length yields one bound state for a molecular dimer for either an attractive or repulsive atom-atom interaction, for a sufficiently small direct background interaction between the atoms a two-channel atom-molecule theory may give two bound states that represent attractively and repulsively bound dimers occurring simultaneously. Such unusual molecular physics may be observable for an atom-molecule coupling strength comparable to the width of the dissociation continuum of the lattice dimer, which is the case, for instance, with narrow Feshbach resonances in Na, {sup 87}Rb, and {sup 133}Cs or low-intensity photoassociation in {sup 174}Yb.

  17. Bound-state formation for thermal relic dark matter and unitarity

    SciTech Connect

    Harling, Benedict von; Petraki, Kalliopi E-mail: kpetraki@nikhef.nl

    2014-12-01

    We show that the relic abundance of thermal dark matter annihilating via a long-range interaction, is significantly affected by the formation and decay of dark matter bound states in the early universe, if the dark matter mass is above a few TeV . We determine the coupling required to obtain the observed dark matter density, taking into account both the direct 2-to-2 annihilations and the formation of bound states, and provide an analytical fit. We argue that the unitarity limit on the inelastic cross-section is realized only if dark matter annihilates via a long-range interaction, and we determine the upper bound on the mass of thermal-relic dark matter to be about 197 (139) TeV for (non)-self-conjugate dark matter.

  18. Detection of Individual Proteins Bound along DNA Using Solid-State Nanopores.

    PubMed

    Plesa, Calin; Ruitenberg, Justus W; Witteveen, Menno J; Dekker, Cees

    2015-05-13

    DNA in cells is heavily covered with all types of proteins that regulate its genetic activity. Detection of DNA-bound proteins is a challenge that is well suited to solid-state nanopores as they provide a linear readout of the DNA and DNA-protein volume in the pore constriction along the entire length of a molecule. Here, we demonstrate that we can realize the detection of even individual DNA-bound proteins at the single-DNA-molecule level using solid-state nanopores. We introduce and use a new model system of anti-DNA antibodies bound to lambda phage DNA. This system provides several advantages since the antibodies bind individually, tolerate high salt concentrations, and will, because of their positive charge, not translocate through the pore unless bound to the DNA. Translocation of DNA-antibody samples reveals the presence of short 12 μs current spikes within the DNA traces, with amplitudes that are about 4.5 times larger than that of dsDNA, which are associated with individual antibodies. We conclude that transient interactions between the pore and the antibodies are the primary mechanism by which bound antibodies are observed. This work provides a proof-of-concept for how nanopores could be used for future sensing applications. PMID:25928590

  19. Bound-state effects on light-element abundances in gravitino dark matter scenarios

    NASA Astrophysics Data System (ADS)

    Cyburt, Richard H.; Ellis, John; Fields, Brian D.; Olive, Keith A.; Spanos, Vassilis C.

    2006-11-01

    If the gravitino is the lightest supersymmetric particle and the long-lived next-to-lightest sparticle (NSP) is the stau, the charged partner of the tau lepton, it may be metastable and form bound states with several nuclei. These bound states may affect the cosmological abundances of 6Li and 7Li by enhancing nuclear rates that would otherwise be strongly suppressed. We consider the effects of these enhanced rates on the final abundances produced in Big-Bang nucleosynthesis (BBN), including injections of both electromagnetic and hadronic energy during and after BBN. We calculate the dominant two- and three-body decays of both neutralino and stau NSPs, and model the electromagnetic and hadronic decay products using the PYTHIA event generator and a cascade equation. Generically, the introduction of bound states drives light element abundances further from their observed values; however, for small regions of parameter space bound-state effects can bring lithium abundances in particular into better accord with observations. We show that in regions where the stau is the NSP with a lifetime longer than 103 104 s, the abundances of 6Li and 7Li are far in excess of those allowed by observations. For shorter lifetimes of order 1000 s, we comment on the possibility in minimal supersymmetric and supergravity models that stau decays could reduce the 7Li abundance from standard BBN values while at the same time enhancing the 6Li abundance.

  20. Scattering and Bound States of Klein-Gordon Particle with Hylleraas Potential Within Effective Mass Formalism

    NASA Astrophysics Data System (ADS)

    Onyeaju, M. C.; Ikot, A. N.; Chukwuocha, E. O.; Obong, H. P.; Zare, S.; Hassanabadi, H.

    2016-06-01

    Scattering and bound states solution for the one-dimensional Klein-Gordon particle with Hylleraas potential is presented within the frame work of position dependent effective mass formalism. We calculate in detail the reflection and transmission coefficients using the properties of hypergeometric functions and the equation of continuity of the wave functions.

  1. The longevity of Jacques Friedel's model of the virtual bound state

    NASA Astrophysics Data System (ADS)

    Levy, Peter M.; Fert, Albert

    2016-03-01

    We illustrate the continuing pertinence of Friedel's model of the virtual bound state to describe electron scattering in metals. This model has been applied to such disparate studies as the chirality of spin interactions in metals, and the spin Hall effect caused by scattering from impurities with spin-orbit coupling. xml:lang="fr"

  2. Resonances from QCD bound states and the 750 GeV diphoton excess

    NASA Astrophysics Data System (ADS)

    Kats, Yevgeny; Strassler, Matthew J.

    2016-05-01

    Pair production of colored particles is in general accompanied by production of QCD bound states (onia) slightly below the pair-production threshold. Bound state annihilation leads to resonant signals, which in some cases are easier to see than the decays of the pair-produced constituents. In a previous paper ( arXiv:1204.1119 ) we estimated the bound state signals, at leading order and in the Coulomb approximation, for particles with various spins, color representations and electric charges, and used 7 TeV ATLAS and CMS resonance searches to set rough limits. Here we update our results to include 8 and 13 TeV data. We find that the recently reported diphoton excesses near 750 GeV could indeed be due to a bound state of this kind. A narrow resonance of the correct size could be obtained for a color-triplet scalar with electric charge -4/3 and mass near 375GeV, if (as a recent lattice computation suggests) the wave function at the origin is somewhat larger than anticipated. Pair production of this particle could have evaded detection up to now. Other candidates may include a triplet scalar of charge 5/3, a triplet fermion of charge -4/3, and perhaps a sextet scalar of charge -2/3.

  3. Fano resonance through Higgs bound states in tunneling of Nambu-Goldstone modes

    NASA Astrophysics Data System (ADS)

    Nakayama, Takeru; Danshita, Ippei; Nikuni, Tetsuro; Tsuchiya, Shunji

    2015-10-01

    We study collective modes of superfluid Bose gases in optical lattices combined with potential barriers. We assume that the system is in the vicinity of the quantum phase transition to a Mott insulator at a commensurate filling, where emergent particle-hole symmetry gives rise to two types of collective mode, namely a gapless Nambu-Goldstone (NG) phase mode and a gapful Higgs amplitude mode. We consider two kinds of potential barrier: One does not break the particle-hole symmetry while the other does. In the presence of the former barrier, we find Higgs bound states that have binding energies lower than the bulk Higgs gap and are localized around the barrier. We analyze tunneling properties of the NG mode incident to both barriers to show that the latter barrier couples the Higgs bound states with the NG mode, leading to Fano resonance mediated by the bound states. Thanks to the universality of the underlying field theory, it is expected that Higgs bound states may be present also in other condensed-matter systems with a particle-hole symmetry and spontaneous breaking of a continuous symmetry, such as quantum dimer antiferromagnets, superconductors, and charge-density-wave materials.

  4. Vibrational overtone spectroscopy of bound and predissociative states of hydrogen peroxide cooled in a supersonic expansion

    SciTech Connect

    Butler, L.; Ticich, T.M.; Likar, M.D.; Crim, F.F.

    1986-08-15

    The vibrational overtone excitation spectra of both bound and predissociative states of hydrogen peroxide molecules cooled in a supersonic expansion show features that are obscured otherwise. Spectra of p-italicr-italice-italicd-italici-italics-italics-italico-italicc-italici-italica-italict-italici-italicv-italice-italic states are measured by detecting the decomposition product following excitation of an overtone vibration. Spectra of b-italico-italicu-italicn-italicd-italic states are obtained by a two-photon excitation technique in which a second photon excites the molecule from its bound vibrational overtone state to a dissociative state. The features in the bound state (4..nu../sub OH/) spectrum are 0.08 to 0.13 cm/sup -1/ wide, reflecting small inhomogeneous broadening, but those to the predissociative state (6..nu../sub OH/) are 1.5 +- 0.3 cm/sup -1/ wide. This width, which corresponds to a lifetime of about 3.5 ps, reflects coupling into the dissociative continuum.

  5. Skyrmion-induced bound states on the surface of 3D Topological Insulators

    NASA Astrophysics Data System (ADS)

    Andrikopoulos, Dimitrios; Soree, Bart

    In this work, we study the interaction between the surface state of a 3D Topological Insulator and a skyrmion magnetic texture. The skyrmion texture couples to the spin of the surface state electron with strength ΔS. Vortex and hedgehog skyrmion and anti-skyrmion structures are considered and their interaction is compared. Due to the vortex structure, the interaction of the in-plane components can be neglected and a step function is used to describe the skyrmion magnetization profile. In the hedgehog case, it is shown that the in-plane components cannot be disregarded and thus a realistic description for the skyrmion is required. Working in the micromagnetic framework, we derive a macrospin description for the skyrmion using the variational principle and then numerically solve for the bound states. It is shown that the existense and properties of these states as a function of skyrmion size, strongly depend on the skyrmion type. Both vortex and hedgehog skyrmions or anti-skyrmions can induce bound states with energies | E | < ΔS . For the hedgehog skyrmion case however, bound state appearance depends on the chirality. Finally, the probability densities in these states are computed and it is demonstrated that the electrons are localized throughout the skyrmion region. Also affiliated with imec, Belgium.

  6. Quasiparticle parity lifetime of bound states in a hybrid superconductor-semiconductor quantum dot

    NASA Astrophysics Data System (ADS)

    Higginbotham, Andrew; Albrecht, Sven; Kirsanskas, Gediminas; Chang, Willy; Kuemmeth, Ferdinand; Krogstrup, Peter; Jespersen, Thomas; Nygård, Jesper; Flensberg, Karsten; Marcus, Charles

    2015-03-01

    We measure quasiparticle transport in an InAs nanowire that is half-covered with epitaxial superconducting aluminum, then locally gated to form a quantum dot. We observe negative differential conductance at finite source-drain bias, and temperature dependent even-odd alternations in the Coulomb blockade peak spacings at zero bias. These observations can be understood in terms of a mid-gap semiconductor discrete state and a continuum of BCS quasiparticle states. Comparing with simple models, we bound the discrete state's parity lifetime and the quasiparticle temperature. These results indicate that parity fluctuations are slow, and imply Majorana qubit poisoning times on the order of a millisecond. Additional results indicate that the bound states move to zero energy in a magnetic field, qualitatively consistent with expectations for Majorana fermions in a finite system. Research supported by Microsoft Station Q, Danish National Research Foundation, Villum Foundation, Lundbeck Foundation, and the European Commission.

  7. Lower bounds to energies for cusped-gaussian wavefunctions. [hydrogen atom ground state

    NASA Technical Reports Server (NTRS)

    Eaves, J. O.; Walsh, B. C.; Steiner, E.

    1974-01-01

    Calculations for the ground states of H, He, and Be, conducted by Steiner and Sykes (1972), show that the inclusion of a very small number of cusp functions can lead to a substantial enhancement of the quality of the Gaussian basis used in molecular wavefunction computations. The properties of the cusped-Gaussian basis are investigated by a calculation of lower bounds concerning the ground state energy of the hydrogen atom.

  8. Delayed birth of distillable entanglement in the evolution of bound entangled states

    SciTech Connect

    Derkacz, Lukasz; Jakobczyk, Lech

    2010-08-15

    The dynamical creation of entanglement between three-level atoms coupled to the common vacuum is investigated. For the class of bound entangled initial states, we show that the dynamics of closely separated atoms generates stationary distillable entanglement of asymptotic states. We also find that the effect of delayed sudden birth of distillable entanglement occurs in the case of atoms separated by a distance comparable with the radiation wavelength.

  9. Bounds on probability of state transfer with respect to readout time and edge weight

    NASA Astrophysics Data System (ADS)

    Gordon, Whitney; Kirkland, Steve; Li, Chi-Kwong; Plosker, Sarah; Zhang, Xiaohong

    2016-02-01

    We analyze the sensitivity of a spin chain modeled by an undirected weighted connected graph exhibiting perfect state transfer to small perturbations in readout time and edge weight in order to obtain physically relevant bounds on the probability of state transfer. At the heart of our analysis is the concept of the numerical range of a matrix; our analysis of edge weight errors additionally makes use of the spectral and Frobenius norms.

  10. Tight bound on coherent-state-based entanglement generation over lossy channels

    SciTech Connect

    Azuma, Koji; Sota, Naoya; Koashi, Masato; Imoto, Nobuyuki

    2010-02-15

    The first stage of the hybrid quantum repeaters is entanglement generation based on transmission of pulses in coherent states over a lossy channel. Protocols to make entanglement with only one type of error are favorable for rendering subsequent entanglement distillation efficient. Here we provide the tight upper bound on performances of these protocols that is determined only by the channel loss. In addition, we show that this bound is achievable by utilizing a proposed protocol [K. Azuma, N. Sota, R. Namiki, S. K. Oezdemir, T. Yamamoto, M. Koashi, and N. Imoto, Phys. Rev. A 80, 060303(R) (2009)] composed of a simple combination of linear optical elements and photon-number-resolving detectors.

  11. Bound states of breathing Airy-Gaussian beams in nonlocal nonlinear medium

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaping

    2016-05-01

    With a nonlocal model, we investigate the propagation dynamics of a single Airy-Gaussian (AiG) beam and their interaction in one-dimensional condition by means of direct numerical simulations. With the split-step Fourier method, numerical results shows that nonlocality can support periodic intensity distribution of AiG beams leading to the formation of stable bound states. Especially, by tuning the phase difference between the two beams, we can steer the center of the bound AiG beams in nonlocal nonlinear media.

  12. Revised magnitude-bound relation for the Wabash Valley seismic zone of the central United States

    USGS Publications Warehouse

    Olson, S.M.; Green, R.A.; Obermeier, S.F.

    2005-01-01

    Seismic hazard assessment in the central United States, and in particular the Wabash Valley seismic zone of Indiana-Illinois, frequently relies on empirical estimates of paleoearthquake magnitudes (M). In large part these estimates have been made using the magnitude-bound method. Existing region-specific magnitude-bound relations rely heavily on only a few historical earthquakes in the central United States and eastern Canada that induced reported liquefaction features. Recent seismological studies have suggested smaller magnitudes than previously presumed for some of these earthquakes, however, and other studies have reinterpreted site-to-source distances to liquefaction features associated with some of these earthquakes. In this paper, we re-examine historical earthquakes (M > ???5) that occurred in the central and eastern United States and eastern Canada; some of these earthquakes triggered liquefaction and others did not. Based on our findings, we reinterpret the region-specific magnitude-bound relation for the Wabash Valley. Using this revised magnitude-bound relation, we present magnitude estimates for four prehistoric earthquakes that occurred in the Wabash Valley seismic zone during Holocene time.

  13. Molecular Andreev bound states and Majorana modes in a double dot system

    NASA Astrophysics Data System (ADS)

    Vernek, Edson; Silva, Joelson F.

    Nanostructured systems such as quantum dots (QD) connected to superconductors has attracted a lot of attention in the recent years. One of the well known phenomena in such a system is the formation of a pair of bound called Andreev bound states (ABS). Recently, it have been shown that when a QD is coupled to a topological superconductor wire, a Majorana bound state (MBS) leaks from the end of the wire into the dot. The character of these bound states is much reacher in structures like molecules and is far from being completely understood. In this work we study a system composed by a two inter-connected QDs in which one of then is coupled to a normal superconductor and to a normal lead while the other is coupled to a topological superconductor and to a distinct normal metallic lead. We show that in the atomic limit (for small interdot coupling), one of the dot has a pair of ABS whereas the other has a single a MBS. More interestingly, in the molecular regime (large inter-dot coupling) we observe a localized Majorana mode coexisting with a delocalized molecular ABS. We would like to thank financial support from the Brazilian agencies CNPq, CAPES and FAPEMIG.

  14. Proximity-induced interface bound states in superconductor-graphene junctions

    NASA Astrophysics Data System (ADS)

    Burset, P.; Herrera, W.; Levy Yeyati, A.

    2009-07-01

    We show that interface bound states are formed at isolated graphene-superconductor junctions. These states arise due to the interplay of virtual Andreev and normal reflections taking place at these interfaces. Simple analytical expressions for their dispersion are obtained considering interfaces formed along armchair or zig-zag edges. It is shown that the states are sensitive to a supercurrent flowing on the superconducting electrode. The states provide long-range superconducting correlations on the graphene layer, which may be exploited for the detection of crossed Andreev processes.

  15. Bound States of (Anti-)Scalar-Quarks in SU(3)c Lattice QCD

    SciTech Connect

    Iida, H.; Takahashi, T. T.; Suganuma, H.

    2007-06-13

    Light scalar-quarks {phi} (colored scalar particles or idealized diquarks) and their color-singlet hadronic states are studied with quenched SU(3)c lattice QCD in terms of mass generation. We investigate 'scalar-quark mesons' {phi}{dagger}{phi} and 'scalar-quark baryons' {phi}{phi}{phi} as the bound states of scalar-quarks {phi}. We also investigate the bound states of scalar-quarks {phi} and quarks {psi}, i.e., {phi}{dagger}{psi}, {psi}{psi}{phi} and {phi}{phi}{psi}, which we name 'chimera hadrons'. All the new-type hadrons including {phi} are found to have a large mass due to large quantum corrections by gluons, even for zero bare scalar-quark mass m{phi} = 0 at a-1 {approx} 1GeV. We conjecture that all colored particles generally acquire a large effective mass due to dressed gluon effects.

  16. Effect of bound-state dressing in laser-assisted radiative recombination

    NASA Astrophysics Data System (ADS)

    Müller, Robert A.; Seipt, Daniel; Fritzsche, Stephan; Surzhykov, Andrey

    2015-11-01

    We present a theoretical study on the recombination of a free electron into the ground state of a hydrogenlike ion in the presence of an external laser field. Emphasis is placed on the effects caused by the laser dressing of the residual ionic bound state. To investigate how this dressing affects the total and angle-differential cross section of laser-assisted radiative recombination (LARR) we apply first-order perturbation theory and the separable Coulomb-Volkov continuum ansatz. Using this approach, detailed calculations are performed for low-Z hydrogenlike ions and laser intensities in the range from IL=1012 to 1013W/cm2 . It is seen that the total cross section as a function of the laser intensity is remarkably affected by the bound-state dressing. Moreover, the laser dressing becomes manifest as asymmetries in the angular distribution and the (energy) spectrum of the emitted recombination photons.

  17. Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms

    NASA Astrophysics Data System (ADS)

    Swann, A. R.; Cassidy, D. B.; Deller, A.; Gribakin, G. F.

    2016-05-01

    Predicted 20 years ago, positron binding to neutral atoms has not yet been observed experimentally. A scheme is proposed to detect positron-atom bound states by colliding Rydberg positronium (Ps) with neutral atoms. Estimates of the charge-transfer reaction cross section are obtained using the first Born approximation for a selection of neutral atom targets and a wide range of incident Ps energies and principal quantum numbers. We also estimate the corresponding Ps ionization cross section. The accuracy of the calculations is tested by comparison with earlier predictions for charge transfer in Ps collisions with hydrogen and antihydrogen. We describe an existing Rydberg Ps beam suitable for producing positron-atom bound states and estimate signal rates based on the calculated cross sections and realistic experimental parameters. We conclude that the proposed methodology is capable of producing such states and of testing theoretical predictions of their binding energies.

  18. Bound states and E8 symmetry effects in perturbed quantum Ising chains

    NASA Astrophysics Data System (ADS)

    Kjäll, Jonas A.; Pollmann, Frank; Moore, Joel E.

    2011-01-01

    In a recent experiment on CoNb2O6, R. Coldea [ScienceSCIEAS0036-807510.1126/science.1180085 327, 177 (2010)] found experimental evidence of the exceptional Lie algebra E8. The emergence of this symmetry was theoretically predicted long ago for the transverse quantum Ising chain in the presence of a weak longitudinal field. We consider an accurate microscopic model of CoNb2O6 incorporating additional couplings and calculate numerically the dynamical structure function using a recently developed matrix-product-state method. The excitation spectra show bound states characteristic of the weakly broken E8 symmetry. We compare the observed bound-state signatures in this model to those found in the transverse Ising chain in a longitudinal field and to experimental data.

  19. Skyrmion-induced bound states on the surface of three-dimensional topological insulators

    NASA Astrophysics Data System (ADS)

    Andrikopoulos, Dimitrios; Sorée, Bart; De Boeck, Jo

    2016-05-01

    The interaction between the surface of a 3D topological insulator and a skyrmion/anti-skyrmion structure is studied in order to investigate the possibility of electron confinement due to the skyrmion presence. Both hedgehog (Néel) and vortex (Bloch) skyrmions are considered. For the hedgehog skyrmion, the in-plane components cannot be disregarded and their interaction with the surface state of the topological insulator (TI) has to be taken into account. A semi-classical description of the skyrmion chiral angle is obtained using the variational principle. It is shown that both the hedgehog and the vortex skyrmion can induce bound states on the surface of the TI. However, the number and the properties of these states depend strongly on the skyrmion type and the skyrmion topological number NSk. The probability densities of the bound electrons are also derived where it is shown that they are localized within the skyrmion region.

  20. Scattering and bound states of spinless particles in a mixed vector-scalar smooth step potential

    SciTech Connect

    Garcia, M.G.; Castro, A.S. de

    2009-11-15

    Scattering and bound states for a spinless particle in the background of a kink-like smooth step potential, added with a scalar uniform background, are considered with a general mixing of vector and scalar Lorentz structures. The problem is mapped into the Schroedinger-like equation with an effective Rosen-Morse potential. It is shown that the scalar uniform background present subtle and trick effects for the scattering states and reveals itself a high-handed element for formation of bound states. In that process, it is shown that the problem of solving a differential equation for the eigenenergies is transmuted into the simpler and more efficient problem of solving an irrational algebraic equation.

  1. Numerical bound state electron dynamics of carbon dioxide in the strong-field regime.

    PubMed

    Smith, Stanley M; Romanov, Dmitri A; Li, Xiaosong; Sonk, Jason A; Schlegel, H Bernhard; Levis, Robert J

    2010-02-25

    Time-dependent Hartree-Fock simulations for a linear triatomic molecule (CO(2)) interacting with a short IR (1.63 eV) three-cycle pulse reveal that the carrier-envelope shape and phase are the essential field parameters determining the bound state electron dynamics during and after the laser-molecule interaction. Analysis of the induced dipole oscillation reveals that the envelope shape (Gaussian or trapezoidal) controls the excited state population distribution. Varying the carrier envelope phase for each of the two pulse envelope shapes considerably changes the excited state populations. Increasing the electric field amplitude alters the relative populations of the excited states, generally exciting higher states. A windowed Fourier transform analysis of the dipole evolution during the laser pulse reveals the dynamics of state excitation and in particular state coupling as the laser intensity increases. PMID:20113001

  2. Majorana bound states from exceptional points in non-topological superconductors.

    PubMed

    San-Jose, Pablo; Cayao, Jorge; Prada, Elsa; Aguado, Ramón

    2016-01-01

    Recent experimental efforts towards the detection of Majorana bound states have focused on creating the conditions for topological superconductivity. Here we demonstrate an alternative route, which achieves fully localised zero-energy Majorana bound states when a topologically trivial superconductor is strongly coupled to a helical normal region. Such a junction can be experimentally realised by e.g. proximitizing a finite section of a nanowire with spin-orbit coupling, and combining electrostatic depletion and a Zeeman field to drive the non-proximitized (normal) portion into a helical phase. Majorana zero modes emerge in such an open system without fine-tuning as a result of charge-conjugation symmetry, and can be ultimately linked to the existence of 'exceptional points' (EPs) in parameter space, where two quasibound Andreev levels bifurcate into two quasibound Majorana zero modes. After the EP, one of the latter becomes non-decaying as the junction approaches perfect Andreev reflection, thus resulting in a Majorana dark state (MDS) localised at the NS junction. We show that MDSs exhibit the full range of properties associated to conventional closed-system Majorana bound states (zero-energy, self-conjugation, 4π-Josephson effect and non-Abelian braiding statistics), while not requiring topological superconductivity. PMID:26865011

  3. Majorana bound states from exceptional points in non-topological superconductors

    NASA Astrophysics Data System (ADS)

    San-Jose, Pablo; Cayao, Jorge; Prada, Elsa; Aguado, Ramón

    2016-02-01

    Recent experimental efforts towards the detection of Majorana bound states have focused on creating the conditions for topological superconductivity. Here we demonstrate an alternative route, which achieves fully localised zero-energy Majorana bound states when a topologically trivial superconductor is strongly coupled to a helical normal region. Such a junction can be experimentally realised by e.g. proximitizing a finite section of a nanowire with spin-orbit coupling, and combining electrostatic depletion and a Zeeman field to drive the non-proximitized (normal) portion into a helical phase. Majorana zero modes emerge in such an open system without fine-tuning as a result of charge-conjugation symmetry, and can be ultimately linked to the existence of ‘exceptional points’ (EPs) in parameter space, where two quasibound Andreev levels bifurcate into two quasibound Majorana zero modes. After the EP, one of the latter becomes non-decaying as the junction approaches perfect Andreev reflection, thus resulting in a Majorana dark state (MDS) localised at the NS junction. We show that MDSs exhibit the full range of properties associated to conventional closed-system Majorana bound states (zero-energy, self-conjugation, 4π-Josephson effect and non-Abelian braiding statistics), while not requiring topological superconductivity.

  4. Majorana bound states from exceptional points in non-topological superconductors

    PubMed Central

    San-Jose, Pablo; Cayao, Jorge; Prada, Elsa; Aguado, Ramón

    2016-01-01

    Recent experimental efforts towards the detection of Majorana bound states have focused on creating the conditions for topological superconductivity. Here we demonstrate an alternative route, which achieves fully localised zero-energy Majorana bound states when a topologically trivial superconductor is strongly coupled to a helical normal region. Such a junction can be experimentally realised by e.g. proximitizing a finite section of a nanowire with spin-orbit coupling, and combining electrostatic depletion and a Zeeman field to drive the non-proximitized (normal) portion into a helical phase. Majorana zero modes emerge in such an open system without fine-tuning as a result of charge-conjugation symmetry, and can be ultimately linked to the existence of ‘exceptional points’ (EPs) in parameter space, where two quasibound Andreev levels bifurcate into two quasibound Majorana zero modes. After the EP, one of the latter becomes non-decaying as the junction approaches perfect Andreev reflection, thus resulting in a Majorana dark state (MDS) localised at the NS junction. We show that MDSs exhibit the full range of properties associated to conventional closed-system Majorana bound states (zero-energy, self-conjugation, 4π-Josephson effect and non-Abelian braiding statistics), while not requiring topological superconductivity. PMID:26865011

  5. Light-Front Hamiltonian Approach to the Bound-State Problem in Quantum Electrodynamics

    NASA Astrophysics Data System (ADS)

    Jones, Billy D.

    1997-10-01

    Why is the study of the Lamb shift in hydrogen, which at the level of detail found in this paper was largely completed by Bethe in 1947, of any real interest today? While completing such a calculation using new techniques may be very interesting for formal and academic reasons, our primary motivation is to lay groundwork for precision bound-state calculations in QCD. The Lamb shift provides an excellent pedagogical tool for illustrating light-front Hamiltonian techniques, which are not widely known; but more importantly it presents three of the central dynamical and computational problems that we must face to make these techniques useful for solving QCD: How does a constituent picture emerge in a gauge field theory? How do bound-state energy scales emerge non-perturbatively? How does rotational symmetry emerge in a non-perturbative light-front calculation?

  6. Bound states for multiple Dirac-δ wells in space-fractional quantum mechanics

    SciTech Connect

    Tare, Jeffrey D. Esguerra, Jose Perico H.

    2014-01-15

    Using the momentum-space approach, we obtain bound states for multiple Dirac-δ wells in the framework of space-fractional quantum mechanics. Introducing first an attractive Dirac-comb potential, i.e., Dirac comb with strength −g (g > 0), in the space-fractional Schrödinger equation we show that the problem of obtaining eigenenergies of a system with N Dirac-δ wells can be reduced to a problem of obtaining the eigenvalues of an N × N matrix. As an illustration we use the present matrix formulation to derive expressions satisfied by the bound-state energies of N = 1, 2, 3 delta wells. We also obtain the corresponding wave functions and express them in terms of Fox's H-function.

  7. Bound-state eigenenergy outside and inside the continuum for unstable multilevel systems

    NASA Astrophysics Data System (ADS)

    Miyamoto, Manabu

    2005-12-01

    The eigenvalue problem for the dressed bound state of unstable multilevel systems is examined both outside and inside the continuum, based on the N -level Friedrichs model, which describes the couplings between the discrete levels and the continuous spectrum. It is shown that a bound-state eigenenergy always exists below each of the discrete levels that lie outside the continuum. Furthermore, by strengthening the couplings gradually, the eigenenergy corresponding to each of the discrete levels inside the continuum finally emerges. On the other hand, the absence of the eigenenergy inside the continuum is proved in weak but finite coupling regimes, provided that each of the form factors that determine the transition between some definite level and the continuum does not vanish at that energy level. An application to the spontaneous emission process for the hydrogen atom interacting with the electromagnetic field is demonstrated.

  8. Realization of negative mass regime and bound state of solitons in inhomogeneous Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Das, Priyam; Khan, Ayan; Panigrahi, Prasanta K.

    2016-05-01

    We study the dispersion mechanism (Lieb-mode excitation) of both single and two-component Bose-Einstein condensates, subject to an external trap in a mean-field approach, where the second quantized Lieb-mode is realized as grey soliton. Through the coupling between the centre of mass motion (Kohn mode) and the soliton's momenta arising from the kinematic chirp, induced by time modulated trap, we realize the exotic negative mass regime of the solitonic excitation. We show that the expulsive parabolic trap significantly modifies the energy-momentum dispersion in the low momenta regime, where these modes can be clearly identified, opening up the possibility to observe the Lieb-mode excitation. In case of two-component, we demonstrate the controlled formation of a bound state, in presence of an expulsive harmonic trap, through the shape compatibility of grey and bright solitons. Possible application of such a bound state to information storage and retrieval is pointed out.

  9. Ultrasensitive optical absorption in graphene based on bound states in the continuum

    PubMed Central

    Zhang, Mingda; Zhang, Xiangdong

    2015-01-01

    We have designed a sphere-graphene-slab structure so that the electromagnetic wave can be well confined in the graphene due to the formation of a bound state in a continuum (BIC) of radiation modes. Based on such a bound state, we have realized strong optical absorption in the monolayer graphene. Such a strong optical absorption exhibits many advantages. It is ultrasensitive to the wavelength because the Q factor of the absorption peak can be more than 2000. By taking suitable BICs, the selective absorption for S and P waves has not only been realized, but also all-angle absorption for the S and P waves at the same time has been demonstrated. We have also found that ultrasensitive strong absorptions can appear at any wavelength from mid-infrared to far-infrared band. These phenomena are very beneficial to biosensing, perfect filters and waveguides. PMID:25652437

  10. Linear set-membership state estimation with unknown but bounded disturbances

    NASA Astrophysics Data System (ADS)

    Foo, Y. K.; Soh, Y. C.; Moayedi, M.

    2012-04-01

    In this article, we consider the problem of discrete-time linear state estimation when at every discrete instant Δ the Euclidean norm of the discrete-time disturbance ‖w(Δ)‖2 is bounded within some known value. Specifically, given a hypersphere that contains the uncertain disturbance signal w(Δ) and an ellipsoid containing the uncertain system state x(Δ) at time step Δ, a sub-optimal approach to computing a linear minimax filter which constructs a minimal ellipsoid to contain x(Δ + 1) is derived. A distinct feature of our approach when compared to earlier solutions is that both the filter and the performance bound can be pre-computed off-line.

  11. Coulomb bound states and resonances due to groups of Ca dimers adsorbed on suspended graphene

    NASA Astrophysics Data System (ADS)

    Saffarzadeh, Alireza; Kirczenow, George

    2014-10-01

    The electronic bound states and resonances in the vicinity of the Dirac point energy due to the adsorption of calcium dimers on a suspended graphene monolayer are explored theoretically using density functional theory (DFT) and an improved extended Hückel model that includes electrostatic potentials. The Mulliken atomic charges and the electrostatic potentials are obtained from DFT calculations and reveal charge transfer from the Ca dimers to the graphene which is responsible for the emergence of resonant states in the electronic spectrum. The number of resonant states increases as the number of adsorbed dimers is increased. We find a bound "atomic-collapse" state in the graphene local density of states, as has been observed experimentally [Wang et al., Science 340, 734 (2013), 10.1126/science.1234320]. We find the formation of the atomic-collapse state and its population with electrons to require fewer adsorbed Ca dimers than in the experiment, possibly due to the different spacing between dimers and the dielectric screening by a boron nitride substrate in the experiment. We also predict the onset of filling of a second atomic-collapse state with electrons when six Ca dimers are adsorbed on the suspended graphene monolayer. Experiments testing these predictions would be of interest.

  12. The lower bound to the concurrence for four-qubit W state under noisy channels

    NASA Astrophysics Data System (ADS)

    Espoukeh, Pakhshan; Pedram, Pouria

    2015-02-01

    We study the dynamics of four-qubit W state under various noisy environments by solving analytically the master equation in the Lindblad form in which the Lindblad operators correspond to the Pauli matrices and describe the decoherence of states. Also, we investigate the dynamics of the entanglement using the lower bound to the concurrence. It is found that while the entanglement decreases monotonically for Pauli-Z noise, it decays suddenly for other three noises. Moreover, by studying the time evolution of entanglement of various maximally entangled four-qubit states, we indicate that the four-qubit W state is more robust under same-axis Pauli channels. Furthermore, three-qubit W state preserves more entanglement with respect to the four-qubit W state, except for the Pauli-Z noise.

  13. Implementation of density functional embedding theory within the projector-augmented-wave method and applications to semiconductor defect states

    NASA Astrophysics Data System (ADS)

    Yu, Kuang; Libisch, Florian; Carter, Emily A.

    2015-09-01

    We report a new implementation of the density functional embedding theory (DFET) in the VASP code, using the projector-augmented-wave (PAW) formalism. Newly developed algorithms allow us to efficiently perform optimized effective potential optimizations within PAW. The new algorithm generates robust and physically correct embedding potentials, as we verified using several test systems including a covalently bound molecule, a metal surface, and bulk semiconductors. We show that with the resulting embedding potential, embedded cluster models can reproduce the electronic structure of point defects in bulk semiconductors, thereby demonstrating the validity of DFET in semiconductors for the first time. Compared to our previous version, the new implementation of DFET within VASP affords use of all features of VASP (e.g., a systematic PAW library, a wide selection of functionals, a more flexible choice of U correction formalisms, and faster computational speed) with DFET. Furthermore, our results are fairly robust with respect to both plane-wave and Gaussian type orbital basis sets in the embedded cluster calculations. This suggests that the density functional embedding method is potentially an accurate and efficient way to study properties of isolated defects in semiconductors.

  14. Implementation of density functional embedding theory within the projector-augmented-wave method and applications to semiconductor defect states

    SciTech Connect

    Yu, Kuang; Libisch, Florian

    2015-09-14

    We report a new implementation of the density functional embedding theory (DFET) in the VASP code, using the projector-augmented-wave (PAW) formalism. Newly developed algorithms allow us to efficiently perform optimized effective potential optimizations within PAW. The new algorithm generates robust and physically correct embedding potentials, as we verified using several test systems including a covalently bound molecule, a metal surface, and bulk semiconductors. We show that with the resulting embedding potential, embedded cluster models can reproduce the electronic structure of point defects in bulk semiconductors, thereby demonstrating the validity of DFET in semiconductors for the first time. Compared to our previous version, the new implementation of DFET within VASP affords use of all features of VASP (e.g., a systematic PAW library, a wide selection of functionals, a more flexible choice of U correction formalisms, and faster computational speed) with DFET. Furthermore, our results are fairly robust with respect to both plane-wave and Gaussian type orbital basis sets in the embedded cluster calculations. This suggests that the density functional embedding method is potentially an accurate and efficient way to study properties of isolated defects in semiconductors.

  15. A search for deeply-bound kaonic nuclear states at J-PARC

    NASA Astrophysics Data System (ADS)

    Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Fukuda, Y.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kienle, P.; Kou, H.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Pietreanu, D.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Sekimoto, M.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    2010-04-01

    The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, K- pp, by the in-flight 3He(K-,n) reaction. The exclusive measurement can be performed by a simultaneous measurement of the missing mass using the primary neutron and the invariant mass via the expected decay, K- pp → Λp → pπ- p. In this report, an overview of the experiment and the preparation status are presented.

  16. A search for deeply bound kaonic nuclear states at J-PARC

    NASA Astrophysics Data System (ADS)

    Hiraiwa, T.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadirenn, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Fukuda, Y.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Iio, M.; Iliescu, M.; Inoue, K.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kienle, P.; Kou, H.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Pietreau, D.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Sekimoto, M.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    2010-08-01

    J-PARC E15 experiment aims to search for the lightest kaonic nuclei, namely K-pp bound states, using in-flight (K-, n) reactions. The advantage of this experiment is to perform exclusive measurement by missing mass study using the primary neutrons and invariant mass spectroscopy via such decay as K-pp→Λp→pπ-p, simultaneously. In this report, an overview of this experiment and the current status are presented.

  17. Explorations in de Sitter space and amorphous black hole bound states in string theory

    NASA Astrophysics Data System (ADS)

    Anous, Tarek

    This dissertation is split into two distinct halves. The first covers various calculations done in order gain insights on holography in de Sitter space. The dispersion relation of linear perturbations of empty de Sitter space are numerically computed as a function of the location of a hypersurface on which conformal Dirichlet boundary conditions are imposed. When the hypersurface is near the south pole, the dispersion relation is linear, whereas for a hypersurface near the cosmological horizon, it satisfies that of the incompressible Navier-Stokes equation. This result is shown to hold for non-linear perturbations. We also compute the thermodynamic stability of rotating black holes in dS4 as a function of their mass and angular momentum. We focus particularly on the rotating Nariai geometry, which is a near horizon limit of the rotating black hole as the outer and cosmological horizons tend towards each other. We study massless scalar fields in these backgrounds and obtain their quasinormal mode spectrum explicitly. We uncover an interesting structure in their two-point functions, namely that they resemble thermal Green's functions of a two-dimensional conformal field theory. The second half of this dissertation deals with the study of multicentered black holes in string theory and their finite temperature extensions. We show that there exist finite temperature single-centered solutions in N = 2 supergravity in asymptotically flat space that admit bound states with BPS probe particles. We compute the existence regions of these bound states as well as their dependence on temperature. We embed these solutions in Fayet-Illiopoulos gauged supergravity and show that bound states persist in asymptotically AdS4 spacetimes. We make attempts to understand these disordered bound states as amorphous/glassy phases of the dual conformal field theory.

  18. Quantum transport through the system of parallel quantum dots with Majorana bound states

    SciTech Connect

    Wang, Ning; Li, Yuxian; Lv, Shuhui

    2014-02-28

    We study the tunneling transport properties through a system of parallel quantum dots which are coupled to Majorana bound states (MBSs). The conductance and spectral function are computed using the retarded Green's function method based on the equation of motion. The conductance of the system is 2e{sup 2}/h at zero Fermi energy and is robust against the coupling between the MBSs and the quantum dots. The dependence of the Fermi energy on the spectral function is different for the first dot (dot1) than for the second dot (dot2) with fixed dot2-MBSs coupling. The influence of the Majorana bound states on the spectral function was studied for the series and parallel configurations of the system. It was found that when the configuration is in series, the Majorana bound states play an important role, resulting in a spectral function with three peaks. However, the spectral function shows two peaks when the system is in a parallel configuration. The zero Fermi energy spectral function is always 1/2 not only in series but also in the parallel configuration and robust against the coupling between the MBSs and the quantum dots. The phase diagram of the Fermi energy versus the quantum dot energy levels was also investigated.

  19. Finite state projection based bounds to compare chemical master equation models using single-cell data.

    PubMed

    Fox, Zachary; Neuert, Gregor; Munsky, Brian

    2016-08-21

    Emerging techniques now allow for precise quantification of distributions of biological molecules in single cells. These rapidly advancing experimental methods have created a need for more rigorous and efficient modeling tools. Here, we derive new bounds on the likelihood that observations of single-cell, single-molecule responses come from a discrete stochastic model, posed in the form of the chemical master equation. These strict upper and lower bounds are based on a finite state projection approach, and they converge monotonically to the exact likelihood value. These bounds allow one to discriminate rigorously between models and with a minimum level of computational effort. In practice, these bounds can be incorporated into stochastic model identification and parameter inference routines, which improve the accuracy and efficiency of endeavors to analyze and predict single-cell behavior. We demonstrate the applicability of our approach using simulated data for three example models as well as for experimental measurements of a time-varying stochastic transcriptional response in yeast. PMID:27544081

  20. Experimental study of bound and autoionizing Rydberg states of the europium atom

    NASA Astrophysics Data System (ADS)

    Xiao, Ying; Dai, Chang-Jian; Qin, Wen-Jie

    2010-06-01

    An isolated-core-excitation (ICE) scheme and stepwise excitation are employed to study the highly excited states of the europium atom. The bound europium spectrum with odd parity in a region of 42400-43500 cm-1 is measured, from which spectral information on 38 transitions, such as level position and relative intensity, can be deduced. Combined with information about excitation calibration and the error estimation process, the selection rules enable us to determine the possible values of total angular momentum J for the observed states. The autoionization spectra of atomic europium, belonging to the 4f76pnl (l = 0, 2) configurations, are systematically investigated by using the three-step laser resonance ionization spectroscopy (RIS) approach. With the ICE scheme, all the experimental spectra of the autoionizing states have nearly symmetric profiles whose peak positions and widths can be easily obtained. A comparison between our results and those from the relevant literature shows that our work not only confirms many reported states, but also discovers 14 bound states and 16 autoionizing states.

  1. Upper bound for SL-invariant entanglement measures of mixed states

    NASA Astrophysics Data System (ADS)

    Osterloh, Andreas

    2016-05-01

    An algorithm is proposed that serves to handle full-rank density matrices when coming from a lower-rank method to compute the convex roof. This is in order to calculate an upper bound for any polynomial SL-invariant multipartite entanglement measure E . This study exemplifies how this algorithm works based on a method for calculating convex roofs of rank-2 density matrices. It iteratively considers the decompositions of the density matrix into two states each, exploiting the knowledge for the rank-2 case. The algorithm is therefore quasiexact as far as the rank-2 case is concerned, and it also hints where it should include more states in the decomposition of the density matrix. Focusing on the measure of three-way entanglement of qubits (called three-tangle), I show the results the algorithm gives for two states, one of which is the Greenberger-Horne-Zeilinger-Werner (GHZ-W ) state, for which the exact convex roof is known. It overestimates the three-tangle in the state, thereby giving insight into the optimal decomposition the GHZ-W state has. As a proof of principle, I have run the algorithm for the three-tangle on the transverse quantum Ising model. I give qualitative and quantitative arguments why the convex roof should be close to the upper bound found here.

  2. Bound and resonant states of muonic molecules below the n =2 level of muonic atoms

    SciTech Connect

    Hara, S. Atomic Processes Laboratory, Institute of Physical and Chemical Research , Wako-shi 351-01, ); Ishihara, T. )

    1989-10-15

    We calculate, by a variational procedure, the bound-state energies of the even-parity muonic molecules with total angular momentum {ital J}=1 and the energies of the ({ital dd}{mu}){sup +} and ({ital dt}{mu}){sup +} resonant states below the {ital n}=2 energy level of muonic atoms. We have found 11 resonant states with {ital J}=0 and 12 with {ital J}=1 for ({ital dd}{mu}){sup +} and 9 states with {ital J}=0 and 10 with {ital J}=1 for ({ital dt}{mu}){sup +}. Some of the resonant energies, relative to the {ital n}=2 level of the muonic atoms, are less than the dissociation energy of D{sub 2}, and therefore these states may play some role in muon-catalyzed fusion.

  3. Universal bound states of two particles in mixed dimensions or near a mirror.

    PubMed

    Tan, Shina

    2012-07-13

    Some novel two-body effects analogous to the well-known three-body Efimov effect are predicted. In the systems considered, particle A is constrained on a truncated or bent one-dimensional line or two-dimensional plane, or on one side of a flat mirror in three dimensions (3D). The constraining potential is fine-tuned such that particle A's ground state wave function is a constant in the region in which it is constrained. Particle B moves in 3D and interacts with particle A, resonantly. An infinite sequence of giant two-body bound states are found in each case. PMID:23030131

  4. Bound states induced giant oscillations of the conductance in the quantum Hall regime

    NASA Astrophysics Data System (ADS)

    Kadigrobov, A. M.; Fistul, M. V.

    2016-06-01

    We theoretically studied the quasiparticle transport in a 2D electron gas biased in the quantum Hall regime and in the presence of a lateral potential barrier. The lateral junction hosts the specific magnetic field dependent quasiparticle states highly localized in the transverse direction. The quantum tunnelling across the barrier provides a complex bands structure of a one-dimensional energy spectrum of these bound states, {εn}≤ft( {{p}y}\\right) , where p y is the electron momentum in the longitudinal direction y. Such a spectrum manifests itself by a large number of peaks and drops in the dependence of the magnetic edge states transmission coefficient D(E ) on the electron energy E. E.g. the high value of D occurs as soon as the electron energy E reaches gaps in the spectrum. These peaks and drops of D(E) result in giant oscillations of the transverse conductance G x with the magnetic field and/or the transport voltage. Our theoretical analysis, based on the coherent macroscopic quantum superposition of the bound states and the magnetic edge states propagating along the system boundaries, is in a good accord with the experimental observations found in Kang et al (2000 Lett. Nat. 403 59)

  5. Bound states induced giant oscillations of the conductance in the quantum Hall regime.

    PubMed

    Kadigrobov, A M; Fistul, M V

    2016-06-29

    We theoretically studied the quasiparticle transport in a 2D electron gas biased in the quantum Hall regime and in the presence of a lateral potential barrier. The lateral junction hosts the specific magnetic field dependent quasiparticle states highly localized in the transverse direction. The quantum tunnelling across the barrier provides a complex bands structure of a one-dimensional energy spectrum of these bound states, [Formula: see text], where p y is the electron momentum in the longitudinal direction y. Such a spectrum manifests itself by a large number of peaks and drops in the dependence of the magnetic edge states transmission coefficient D(E ) on the electron energy E. E.g. the high value of D occurs as soon as the electron energy E reaches gaps in the spectrum. These peaks and drops of D(E) result in giant oscillations of the transverse conductance G x with the magnetic field and/or the transport voltage. Our theoretical analysis, based on the coherent macroscopic quantum superposition of the bound states and the magnetic edge states propagating along the system boundaries, is in a good accord with the experimental observations found in Kang et al (2000 Lett. Nat. 403 59). PMID:27166511

  6. Repulsively bound exciton-biexciton states in high-spin fermions in optical lattices

    SciTech Connect

    Argueelles, A.; Santos, L.

    2011-03-15

    We show that the interplay between spin-changing collisions and quadratic Zeeman coupling provides a mechanism for the formation of repulsively bound composites in high-spin fermions, which we illustrate by considering spin flips in an initially polarized hard-core one-dimensional Mott insulator of spin-3/2 fermions. We show that after the flips the dynamics is characterized by the creation of two types of exciton-biexciton composites. We analyze the conditions for the existence of these bound states and discuss their intriguing properties. In particular we show that the effective mass and stability of the composites depends nontrivially on spin-changing collisions, on the quadratic Zeeman effect, and on the initial exciton localization. Finally, we show that the composites may remain stable against inelastic collisions, opening the possibility of interesting quantum composite phases.

  7. Bound and scattering states in harmonic waveguides in the vicinity of free space Feshbach resonances

    NASA Astrophysics Data System (ADS)

    Wang, Gaoren; Giannakeas, Panagiotis; Schmelcher, Peter

    2016-08-01

    The two-body bound and scattering properties in an one-dimensional harmonic waveguide close to free space magnetic Feshbach resonances are investigated based on the local frame transformation approach within a single partial wave approximation. An energy and magnetic field dependent free space phase shift is adopted in the current theoretical framework. For both s- and p-wave interaction, the least bound state in the waveguide dissociates into the continuum at the resonant magnetic field where the effective one-dimensional scattering length {a}{{1D}} diverges. Consequently, the association of atoms into molecules in the waveguide occurs when the magnetic field is swept adiabatically across the pole of {a}{{1D}}. In the vicinity of broad s-wave resonances, the resonant magnetic field is nearly independent on the transverse confining frequency {ω }\\perp of the waveguide. Close to p-wave and narrow s-wave resonances, the resonant magnetic field changes as {ω }\\perp varies.

  8. Structure Analysis and Conformational Transitions of the Cell Penetrating Peptide Transportan 10 in the Membrane-Bound State

    PubMed Central

    Strandberg, Erik; Verdurmen, Wouter P. R.; Bürck, Jochen; Ehni, Sebastian; Mykhailiuk, Pavel K.; Afonin, Sergii; Gerthsen, Dagmar; Komarov, Igor V.; Brock, Roland; Ulrich, Anne S.

    2014-01-01

    Structure analysis of the cell-penetrating peptide transportan 10 (TP10) revealed an exemplary range of different conformations in the membrane-bound state. The bipartite peptide (derived N-terminally from galanin and C-terminally from mastoparan) was found to exhibit prominent characteristics of (i) amphiphilic α-helices, (ii) intrinsically disordered peptides, as well as (iii) β-pleated amyloid fibrils, and these conformational states become interconverted as a function of concentration. We used a complementary approach of solid-state 19F-NMR and circular dichroism in oriented membrane samples to characterize the structural and dynamical behaviour of TP10 in its monomeric and aggregated forms. Nine different positions in the peptide were selectively substituted with either the L- or D-enantiomer of 3-(trifluoromethyl)-bicyclopent-[1.1.1]-1-ylglycine (CF3-Bpg) as a reporter group for 19F-NMR. Using the L-epimeric analogs, a comprehensive three-dimensional structure analysis was carried out in lipid bilayers at low peptide concentration, where TP10 is monomeric. While the N-terminal region is flexible and intrinsically unstructured within the plane of the lipid bilayer, the C-terminal α-helix is embedded in the membrane with an oblique tilt angle of ∼55° and in accordance with its amphiphilic profile. Incorporation of the sterically obstructive D-CF3-Bpg reporter group into the helical region leads to a local unfolding of the membrane-bound peptide. At high concentration, these helix-destabilizing C-terminal substitutions promote aggregation into immobile β-sheets, which resemble amyloid fibrils. On the other hand, the obstructive D-CF3-Bpg substitutions can be accommodated in the flexible N-terminus of TP10 where they do not promote aggregation at high concentration. The cross-talk between the two regions of TP10 thus exerts a delicate balance on its conformational switch, as the presence of the α-helix counteracts the tendency of the unfolded N

  9. On bound state computations in three- and four-electron atomic systems

    SciTech Connect

    Frolov, A. M. Wardlaw, D. M.

    2010-07-15

    A variational approach is developed for bound state calculations in three- and four-electron atomic systems. This approach can be applied to determine, in principle, an arbitrary bound state in three- and four-electron ions and atoms. Our variational wave functions are constructed from four- and five-body Gaussoids that respectively depend on six (r{sub 12}, r{sub 13}, r{sub 14}, r{sub 23}, r{sub 24}, r{sub 34}) and ten (r{sub 12}, r{sub 13}, r{sub 14}, r{sub 15}, r{sub 23}, r{sub 24}, r{sub 25}, r{sub 34}, r{sub 35} and r{sub 45}) relative coordinates. The approach allows operating with the more than one electron spin functions. In particular, the trial wave functions for the {sup 1}S states in four-electron atomic systems include the two independent spin functions {chi}{sub 1} = {alpha}{beta}{alpha}{beta} + {beta}{alpha}{beta}{alpha} - {beta}{alpha}{alpha}{beta} - {alpha}{beta}{beta}{alpha} and {chi}{sub 2} = 2{alpha}{alpha}{beta}{beta} + 2{beta}{beta}{alpha}{alpha} - {beta}{alpha}{alpha}{beta} - {alpha}{beta}{beta}{alpha} - {beta}{alpha}{beta}{alpha} - {alpha}{beta}{alpha}{beta}. We also discuss the construction of variational wave functions for the excited 2{sup 3}S states in four- electron atomic systems.

  10. Melting behavior and different bound states in three-stranded DNA models.

    PubMed

    Maji, Jaya; Bhattacharjee, Somendra M; Seno, Flavio; Trovato, Antonio

    2014-01-01

    Thermal denaturation of DNA is often studied with coarse-grained models in which native sequential base pairing is mimicked by the existence of attractive interactions only between monomers at the same position along strands (Poland and Scheraga models). Within this framework, the existence of a three-stranded DNA bound state in conditions where a duplex DNA would be in the denaturated state was recently predicted from a study of three directed polymer models on simplified hierarchical lattices (d>2) and in 1+1 dimensions. Such a phenomenon which is similar to the Efimov effect in nuclear physics was named Efimov-DNA. In this paper we study the melting of the three-stranded DNA on a Sierpinski gasket of dimensions d<2 by assigning extra weight factors to fork openings and closings, to induce a two-strand DNA melting. In such a context we can find again the existence of the Efimov-DNA-like state but quite surprisingly we discover also the presence of a different phase, to be called a mixed state, where the strands are pair-wise bound but without three chain contacts. Whereas the Efimov DNA turns out to be a crossover near melting, the mixed phase is a thermodynamic phase. PMID:24580186

  11. Theoretical study of the low-lying bound states of O2

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

    1991-01-01

    It is demonstrated that a complete-active-space self-consistent-field (CASSCF) (2p)/MRCI + Q (multireference configuration interaction with a Davidson correction) description in a (13s8p6d 4f2g)/((5s4p3d 2f1g) atomic natural orbits (ANO) basis set supplemented with diffuse functions provides a quantitative description of the six lowest states of O2. The calculated potentials are within 0.05 eV (1.2 kilocal/mol) of accurate experimental results. The importance of substantially expanding the primitive basis set has been investigated, and it is demonstrated that such expansions yield insignificant improvement in the spectroscopic constants. Potential energy curves have also been reported for the weakly bound states of O2. The 5Pi(g) state is estimated to have a D(e) of 0.16 +/- 0.03 eV. The upper bound of D(e) is found to be sufficiently large that the importance of this state as a precursor for the formation of O2 (b 1Sigma(t)(+)) and O(1S) should be reconsidered.

  12. Bound states of the spin-orbit coupled ultracold atom in a one-dimensional short-range potential

    SciTech Connect

    Jursenas, Rytis; Ruseckas, Julius

    2013-05-15

    We solve the bound state problem for the Hamiltonian with the spin-orbit and the Raman coupling included. The Hamiltonian is perturbed by a one-dimensional short-range potential V which describes the impurity scattering. In addition to the bound states obtained by considering weak solutions through the Fourier transform or by solving the eigenvalue equation on a suitable domain directly, it is shown that ordinary point-interaction representations of V lead to spin-orbit induced extra states.

  13. Formation of Triplet Positron-helium Bound State by Stripping of Positronium Atoms in Collision with Ground State Helium

    NASA Technical Reports Server (NTRS)

    Drachman, Richard J.

    2006-01-01

    Formation of triplet positron-helium bound state by stripping of positronium atoms in collision with ground state helium JOSEPH DI RlENZI, College of Notre Dame of Maryland, RICHARD J. DRACHMAN, NASA/Goddard Space Flight Center - The system consisting of a positron and a helium atom in the triplet state e(+)He(S-3)(sup e) was conjectured long ago to be stable [1]. Its stability has recently been established rigorously [2], and the values of the energies of dissociation into the ground states of Ps and He(+) have also been reported [3] and [4]. We have evaluated the cross-section for this system formed by radiative attachment of a positron in triplet He state and found it to be small [5]. The mechanism of production suggested here should result in a larger cross-section (of atomic size) which we are determining using the Born approximation with simplified initial and final wave functions.

  14. Autoregressive modeling with state-space embedding vectors for damage detection under operational and environmental variability

    SciTech Connect

    Farrar, Charles; Figueiredo, Eloi; Todd, Michael; Flynn, Eric

    2010-01-01

    A nonlinear time series approach is presented to detect damage in systems by using a state-space reconstruction to infer the geometrical structure of a deterministic dynamical system from observed time series response at multiple locations. The unique contribution of this approach is using a Multivariate Autoregressive (MAR) model of a baseline condition to predict the state space, where the model encodes the embedding vectors rather than scalar time series. A hypothesis test is established that the MAR model will fail to predict future response if damage is present in the test condition, and this test is investigated for robustness in the context of operational and environmental variability. The applicability of this approach is demonstrated using acceleration time series from a base-excited 3-story frame structure.

  15. Nuclear Bound States of Molecular Hydrogen Physisorbed on Graphene: An Effective Two-Dimensional Model.

    PubMed

    de Lara-Castells, María Pilar; Mitrushchenkov, Alexander O

    2015-11-01

    The interaction potential of molecular hydrogen physisorbed on a graphene sheet is evaluated using the ab initio-based periodic dlDF+Das scheme and its accuracy is assessed by comparing the nuclear bound-state energies supported by the H2(D2/HD)/graphite potentials with the experimental energies. The periodic dlDF+Das treatment uses DFT-based symmetry-adapted perturbation theory on surface cluster models to extract the dispersion contribution to the interaction whereas periodic dispersionless density functional (dlDF) calculations are performed to determine the dispersion-free counterpart. It is shown that the H2/graphene interaction is effectively two-dimensional (2D), with the distance from the molecule center-of-mass to the surface plane and the angle between the diatomic axis and the surface normal as the relevant degrees of freedom. The global potential minimum is found at the orthogonal orientation of the molecule with respect to the surface plane, with an equilibrium distance of 3.17 Å and a binding energy of -51.9 meV. The comparison of the binding energies shows an important improvement of our approach over the vdW-corrected DFT schemes when we are dealing with the very weak H2/surface interaction. Next, the 2D nuclear bound-state energies are calculated numerically. As a cross-validation of the interaction potential, the bound states are also determined for molecular hydrogen on the graphite surface (represented as an assembly of graphene sheets). With the largest absolute deviation being 1.7 meV, the theoretical and experimental energy levels compare very favorably. PMID:26479965

  16. Helical Spin Texture and Interference of Majorana Bound States in One-Dimensional Topological Superconductor

    NASA Astrophysics Data System (ADS)

    Kawakami, Takuto; Hu, Xiao

    2016-01-01

    We investigate one-dimensional (1D) Majorana bound states (MBSs) realized in terms of the helical edge states of a 2D quantum spin-Hall insulator in a heterostructure with a superconducting substrate and two ferromagnetic insulators (FIs). By means of Bogoliubov-de Gennes approach we demonstrate that there is a helical spin texture in the MBS wave function with a pitch proportional to the Fermi momentum. Moreover, simultaneous detection on local density of states by scanning tunneling microscopy and spectroscopy at a position close to one FI edge and at the midpoint between the two FIs can not only map out the energy spectrum ±E cos(ϕ/2) where ϕ is the relative angle between the magnetizations of two FIs, but also prove experimentally that the two quasiparticle excitations do not mix with each other as protected by the parity conservation associated with the MBSs.

  17. Observation of broken time-reversal symmetry with Andreev bound state tunneling spectroscopy

    NASA Astrophysics Data System (ADS)

    Greene, L. H.; Covington, M.; Aprili, M.; Badica, E.; Pugel, D. E.

    2000-05-01

    Quasiparticle (QP) planar tunneling spectroscopy is used to investigate the density of states (DoS) of YBa 2Cu 3O 7 (YBCO). Temperature, crystallographic orientation, doping, damage and magnetic field dependencies confirm that the observed zero-bias conductance peak (ZBCP) is an Andreev bound state (ABS), an intrinsic property of a d-wave superconducting order parameter (OP) at an interface. In zero applied field, the splitting of the ZBCP below ∼8 K confirms a near-surface phase transition into a superconducting state with spontaneously broken time-reversal symmetry (BTRS). Tunneling into the ABS provides a phase-sensitive spectroscopy that can be used to measure a variety of DoS properties in an unconventional superconductor.

  18. Cavity-Free Photon Blockade Induced by Many-Body Bound States

    NASA Astrophysics Data System (ADS)

    Zheng, Huaixiu; Gauthier, Daniel; Baranger, Harold

    2012-02-01

    We show theoretically that a variety of strong quantum nonlinear phenomena occur in a completely open one-dimensional waveguide coupled to an N-type four-level system. This system could be realized, for example, in experiments using superconducting circuits. We focus on photon blockade, photon-induced tunneling, bunching or anti-bunching, and the creation of single-photon states, all in the absence of a cavity. Many-body bound states appear due to the strong photon-photon correlation mediated by the four-level system. These bound states cause photon blockade, generating a sub-Poissonian single-photon source [1]. Such a source is crucial for quantum cryptography and distributed quantum networking; our work thus supports the notion that open quantum systems can play a critical role in the manipulation of individual, mobile quanta, a key goal of quantum communication. [1] H. Zheng, D. J. Gauthier, and H. U. Baranger, Phys. Rev. Lett. in press (2011), arXiv:1107.0309.

  19. Studies of K-absorption on light nuclei and the search for bound nuclear kaonic states

    NASA Astrophysics Data System (ADS)

    Filippi, Alessandra; Piano, Stefano

    2011-09-01

    The available experimental data on K-absorption on nuclei are rather old and scarce: they are not enough to understand the possible formation of aggregates of nucleons bound together by a kaon, known as "Bound Kaonic Nuclear States". The existence of such structures, suggested by a few theoretical models, has not been experimentally ascertained yet. To be observed, their width should be less than their binding energy. A possible decay channel for such states is the non mesonic one, leading to hyperon-nucleon (or light nuclei) final states. Therefore, experimental investigations of possible signatures are mainly based on the analysis of hyperon-nucleon(s) correlations (for instance, of Λp(d,t) pairs) and of invariant mass spectra. Complementary information may also be gathered from missing mass distributions. Recent experiments revived, with much larger statistics, the study of K-A absorption in light nuclei: namely, KEK-E549 studied the K-interactions on 4He, while FINUDA at DAΦNE collected a large statistics on K-6,7Li, K-9Be and K-12C. The experimental results obtained so far by the various experiments studying the K-absorption in nuclei are here summarized.

  20. Critical Current, Vortices and Fermionic Bound States in the BEC to BCS Crossover

    NASA Astrophysics Data System (ADS)

    Sensarma, Rajdeep; Randeria, Mohit; Lun Ho, Tin

    2006-03-01

    We have analyzed a single vortex at T=0 in a 3D superfluid atomic Fermi gas across a Feshbach resonance[1] using a fully self-consistent Bogoliubov-deGennes approach. From the current flow around a vortex we conclude that unitarity (as= ∞) is the most robust superfluid state in the entire BCS-BEC crossover, with the highest critical velocity vc of about 0.1vF. On either side of unitarity, vc decreases. It is determined by pair breaking on the BCS side and by collective excitations in the BEC regime. In the BCS limit, the order parameter near the vortex core shows a variation on both the scale of kF-1 and of the coherence length ξ, while away from the BCS limit only a variation on the scale of ξ is seen. The density in the core rises quadratically with radial distance and is progressively depleted as one moves from BCS to BEC. The number of fermionic bound states in the core decreases as we move from the BCS to BEC regime. Remarkably, a bound state branch persists even on the BEC side reflecting the composite nature of bosonic molecules.[1] R. Sensarma, M. Randeria and T.L. Ho, cond-mat/0510761

  1. Bound and continuum states of molecular anions C2H- and C3N-

    NASA Astrophysics Data System (ADS)

    Harrison, Stephen; Tennyson, Jonathan

    2011-02-01

    Recently a number of molecular anions, closed-shell linear carbon chains of the form CnH- and CnN-, have been detected in space. The molecules C2H- and C3N- are investigated by using the R-matrix method to consider electron scattering from the corresponding neutral targets. Initial target calculations are conducted and refined in order to produce target state characteristics similar to the experimental data. A number of different scattering models are tested including static exchange and close-coupling models, and the use of Hartree-Fock or natural orbitals in the close-coupling calculations. The calculations concentrate on bound and resonances states for the anions as well as eigenphase sums, elastic cross-sections and electronic excitation cross-sections for electron collisions with the neutral. It is found that electronic resonances are all too high in energy to be important for anion formation in the interstellar medium. However, C3N-, unlike C2H-, supports a number of very weakly bound excited states, which may well provide the route to electron attachment for this system.

  2. Bound states and quantization of screening in the Wannier-Mott excitons

    SciTech Connect

    Makowski, Adam J.

    2011-02-15

    The problem of validity of the simple relation {lambda}=(n+2l)(n+2l+1) between the screening length {lambda} and the number of bound states in the Stern-Howard potential is discussed and the results are compared with those obtained for some potential with the same limiting behavior as the former one. The main conclusion of the present study is that the above relation does not hold for the Stern-Howard potential but most likely it is very close to an unknown relation to be discovered for the potential.

  3. A Search for Deeply Bound Kaonic Nuclear States at J-PARC

    NASA Astrophysics Data System (ADS)

    Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kawasaki, S.; Kienle, P.; Kou, H.; Ma, Y.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Lener, M. Poli; Vidal, A. Romero; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Doce, O. Vazquez; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    2013-08-01

    The J-PARC E15 experiment has the aims to search for the simplest kaonic nuclear bound state, K - pp, by the in-flight 3He( K -, n) reaction. The exclusive measurement is performed by a simultaneous measurement of the missing mass using the knocked out neutron and the invariant mass via the expected decay, K - pp → Λ p → pπ- p. In this paper, an overview of the experiment and current data analysis of the engineering runs performed in February and June 2012 are presented.

  4. Formation of η'(958) Meson Bound States and Chiral Symmetry In-Medium

    NASA Astrophysics Data System (ADS)

    Nagahiro, Hideko

    2013-08-01

    We theoretically discuss the feasibility to observe the η'(958)-mesic nuclei by using the missing mass spectroscopy. We evaluate the η'-nucleus optical potential including the contribution of lowest order in density together with the second order terms account for η' absorption by two nucleons, based on a recent model of the η' N interaction. We show the calculated formation cross section of the η' bound states from ( π, N) reaction with pion beam momentum p π = 1.8 GeV/c and ( p, d) reaction with proton kinetic energy T p = 2.5 GeV.

  5. Solitons shedding from Airy beams and bound states of breathing Airy solitons in nonlocal nonlinear media

    PubMed Central

    Shen, Ming; Gao, Jinsong; Ge, Lijuan

    2015-01-01

    We investigate the spatially optical solitons shedding from Airy beams and anomalous interactions of Airy beams in nonlocal nonlinear media by means of direct numerical simulations. Numerical results show that nonlocality has profound effects on the propagation dynamics of the solitons shedding from the Airy beam. It is also shown that the strong nonlocality can support periodic intensity distribution of Airy beams with opposite bending directions. Nonlocality also provides a long-range attractive force between Airy beams, leading to the formation of stable bound states of both in-phase and out-of-phase breathing Airy solitons which always repel in local media. PMID:25900878

  6. The beauty of impurities: Two revivals of Friedel's virtual bound-state concept

    NASA Astrophysics Data System (ADS)

    Georges, Antoine

    2016-03-01

    Jacques Friedel pioneered the theoretical study of impurities and magnetic impurities in metals. He discovered Friedel oscillations, introduced the concept of virtual bound-state, and demonstrated that the charge on the impurity is related to the scattering phase-shift at the Fermi level (Friedel sum-rule). After a brief review of some of these concepts, I describe how they proved useful in two new contexts. The first one concerns the Coulomb blockade in quantum dots, and its suppression by the Kondo effect. The second one is the dynamical mean-field theory of strong electronic correlations. xml:lang="fr"

  7. Quantum localization and bound-state formation in Bose-Einstein condensates

    SciTech Connect

    Franzosi, Roberto; Giampaolo, Salvatore M.; Illuminati, Fabrizio

    2010-12-15

    We discuss the possibility of exponential quantum localization in systems of ultracold bosonic atoms with repulsive interactions in open optical lattices without disorder. We show that exponential localization occurs in the maximally excited state of the lowest energy band. We establish the conditions under which the presence of the upper energy bands can be neglected, determine the successive stages and the quantum phase boundaries at which localization occurs, and discuss schemes to detect it experimentally by visibility measurements. The discussed mechanism is a particular type of quantum localization that is intuitively understood in terms of the interplay between nonlinearity and a bounded energy spectrum.

  8. Observation of Excitonic N-Body Bound States: Polyexcitons in Diamond

    NASA Astrophysics Data System (ADS)

    Omachi, J.; Suzuki, T.; Kato, K.; Naka, N.; Yoshioka, K.; Kuwata-Gonokami, M.

    2013-07-01

    We have found a series of resonances associated with the bound state (polyexcitons, PENs) of N excitons up to N=6 in the emission spectra of diamond under two-photon excitation at around 10 K. Time-resolved spectra show a stepwise formation of PENs with smaller to larger N, as well as a successive decay from larger to smaller N. At higher excitation levels, the transformation of PENs into a condensed phase of electron-hole droplets occurs. The binding energies of the PENs, normalized to the exciton Rydberg energy, agree well with those of silicon, suggesting the universality of the phenomena.

  9. J/{Psi} Mass Shift and J/{Psi}-Nuclear Bound State

    SciTech Connect

    Tsushima, Kazuo; Thomas, Anthony W.; Lu, D. H.; Krein, Gastao

    2011-05-24

    We calculate mass shift of the J/{Psi} meson in nuclear matter arising from the modification of DD, DD* and D*D* meson loop contributions to the J/{Psi} self-energy. The estimate includes the in-medium D and D* meson masses consistently. The J/{Psi} mass shift (scalar potential) calculated is negative (attractive), and is complementary to the attractive potential obtained from the QCD color van der Waals forces. Some results for the J/{Psi}-nuclear bound state energies are also presented.

  10. J/Ψ Mass Shift and J/Ψ-Nuclear Bound State

    NASA Astrophysics Data System (ADS)

    Tsushima, Kazuo; Lu, D. H.; Krein, Gastao; Thomas, Anthony W.

    2011-05-01

    We calculate mass shift of the J/Ψ meson in nuclear matter arising from the modification of DD, DD* and D*D* meson loop contributions to the J/Ψ self-energy. The estimate includes the in-medium D and D* meson masses consistently. The J/Ψ mass shift (scalar potential) calculated is negative (attractive), and is complementary to the attractive potential obtained from the QCD color van der Waals forces. Some results for the J/Ψ-nuclear bound state energies are also presented.

  11. Bounded energy states in homogeneous turbulent shear flow - An alternative view

    NASA Technical Reports Server (NTRS)

    Bernard, P. S.; Speziale, C. G.

    1992-01-01

    The equilibrium structure of homogeneous turbulent shear flow is investigated from a theoretical standpoint. Existing turbulence models, in apparent agreement with physical and numerical experiments, predict an unbounded exponential time growth of the turbulent kinetic energy and dissipation rate; only the anisotropy tensor and turbulent time scale reach a structural equilibrium. It is shown that if a residual vortex stretching term is maintained in the dissipation rate transport equation, then there can exist equilibrium solutions, with bounded energy states, where the turbulence production is balanced by its dissipation. Illustrative calculations are presented for a k-epsilon model modified to account for net vortex stretching.

  12. Search for the η-mesic Helium bound state with the WASA-at-COSY facility

    NASA Astrophysics Data System (ADS)

    Skurzok, Magdalena; Krzemień, Wojciech; Rundel, Oleksandr; Moskal, Pawel

    2016-05-01

    We performed a search for 4He-η bound state with high statistics and high acceptance with the WASA-at-COSY facility using a ramped beam technique. The signature of η-mesic nuclei is searched for in dd → 3Henπ0 and dd → 3Hepπ- reactions by the measurement of the excitation functions in the vicinity of the η production threshold. This paper presents the experimental method and the preliminary results of the data analysis for dd → 3Henπ0 process.

  13. K- absorption on two nucleons and ppK- bound state search in the Σ0p final state

    NASA Astrophysics Data System (ADS)

    Vázquez Doce, O.; Fabbietti, L.; Cargnelli, M.; Curceanu, C.; Marton, J.; Piscicchia, K.; Scordo, A.; Sirghi, D.; Tucakovic, I.; Wycech, S.; Zmeskal, J.; Anastasi, A.; Curciarello, F.; Czerwinski, E.; Krzemien, W.; Mandaglio, G.; Martini, M.; Moskal, P.; Patera, V.; Pérez del Rio, E.; Silarski, M.

    2016-07-01

    We report the measurement of K- absorption processes in the Σ0p final state and the first exclusive measurement of the two nucleon absorption (2NA) with the KLOE detector. The 2NA process without further interactions is found to be 9% of the sum of all other contributing processes, including absorption on three and more nucleons or 2NA followed by final state interactions with the residual nucleons. We also determine the possible contribution of the ppK- bound state to the Σ0p final state. The yield of ppK- / Kstop- is found to be (0.044 ± 0.009stat-0.005+0.004 syst) ṡ10-2 but its statistical significance based on an F-test is only 1σ.

  14. Strictly-complete measurements for bounded-rank quantum-state tomography

    NASA Astrophysics Data System (ADS)

    Baldwin, Charles H.; Deutsch, Ivan H.; Kalev, Amir

    2016-05-01

    We consider the problem of quantum-state tomography under the assumption that the state is pure, and more generally that its rank is bounded by a given value r . In this scenario two notions of informationally complete measurements emerge: rank-r -complete measurements and rank-r strictly-complete measurements. Whereas in the first notion, a rank-r state is uniquely identified from within the set of rank-r states, in the second notion the same state is uniquely identified from within the set of all physical states, of any rank. We argue, therefore, that strictly-complete measurements are compatible with convex optimization, and we prove that they allow robust quantum-state estimation in the presence of experimental noise. We also show that rank-r strictly-complete measurements are as efficient as rank-r -complete measurements. We construct examples of strictly-complete measurements and give a complete description of their structure in the context of matrix completion. Moreover, we numerically show that a few random bases form such measurements. We demonstrate the efficiency-robustness property for different strictly-complete measurements with numerical experiments. We thus conclude that only strictly-complete measurements are useful for practical tomography.

  15. Search for deeply bound Kaonic nuclear states via 3He(K-, n) reaction at J-PARC

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kato, Y.; Kawasaki, S.; Kienle, P.; Kou, H.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Lener, M. Poli; Vidal, A. Romero; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tanida, K.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Vazquez Doce, O.; Widmann, E.; Wuenschek, B. K.; Yamaga, T.; Yamazaki, T.; Yim, H.; Zhang, Q.; Zmeskal, J.

    2015-10-01

    As the latest effort to search for deeply-bound overline K-nuclear states, E15 experiment has been carried out at K1.8 branch beam line (K1.8BR) at J-PARC. 3He(K-, N) reaction was employed to search for the simplest overline K-nuclear bound state, K--pp. In this proceeding, preliminary results of 3He(K-, n) spectra obtained in the first physics-run will be presented.

  16. Role of the bound-state wave function in capture-loss rates: Slow proton in an electron gas

    SciTech Connect

    Alducin, M.; Nagy, I.

    2003-07-01

    Capture and loss rates for protons moving in an electron gas are calculated using many-body perturbation theory. The role of the form of the bound-state wave function for weakly bound states around the proton is analyzed. We find significant differences (up to a factor of 2 higher) in the values of Auger capture and loss rates when using Hulthen-type instead of hydrogenic wave functions. Its relevance in stopping power is briefly discussed.

  17. Steering Bound Entangled States: A Counterexample to the Stronger Peres Conjecture

    NASA Astrophysics Data System (ADS)

    Moroder, Tobias; Gittsovich, Oleg; Huber, Marcus; Gühne, Otfried

    2014-08-01

    Quantum correlations are at the heart of many applications in quantum information science and, at the same time, they form the basis for discussions about genuine quantum effects and their difference to classical physics. On one hand, entanglement theory provides the tools to quantify correlations in information processing and many results have been obtained to discriminate useful entanglement, which can be distilled to a pure form, from bound entanglement, being of limited use in many applications. On the other hand, for discriminating quantum phenomena from their classical counterparts, Schrödinger and Bell introduced the notions of steering and local hidden variable models. We provide a method to generate systematically bound entangled quantum states which can still be used for steering and, therefore, to rule out local hidden state models. This sheds light on the relations between the various views on quantum correlations and disproves a widespread conjecture known as the stronger Peres conjecture. For practical applications, it implies that even the weakest form of entanglement can be certified in a semidevice independent way.

  18. Negative Delta-Rho in the "standard Model" from 4TH-GENERATION Bound States

    NASA Astrophysics Data System (ADS)

    McCoy, Richard Thomas, III

    The possible consequences of heavy fourth-generation "vector meson" bound states, formed by the exchange of the Higgs boson, are discussed within the context of the Standard Model with either one or two Higgs doublets. It is suggested that such bound states could make negative contributions to the rho parameter, thereby loosening the perturbative constraint upon the mass of the top quark (our model would permit rm m_{t} to be as large as 365 GeV in the one Higgs doublet scenario, for example) and/or the masses, mass splittings, and other characteristics of a potential fourth generation of heavy fermions. In the two Higgs doublet scenario, the contributions to the rho parameter coming solely from the scalar sector are also considered. It is found in that scenario that the way fermions couple to the Higgs doublets crucially determines whether or not one can have a heavy (>150 GeV) top quark, a light ( <80 GeV) charged scalar and/or rare "monojet" Z decays such as Z to Nnu _tau, where N is the fourth-generation neutral lepton.

  19. Shot noise in a quantum dot system coupled with Majorana bound states

    NASA Astrophysics Data System (ADS)

    Chen, Qiao; Chen, Ke-Qiu; Zhao, Hong-Kang

    2014-08-01

    We investigate the spectral density of shot noise and current for the system of a quantum dot coupled to Majorana bound states (MBS) employing the nonequilibrium Green’s function. The Majorana bound states at the end of the wire strongly affect the shot noise. There are two types of coupling in the system: dot-MBS and MBS-MBS coupling. The curves of shot noise and current versus coupling strength have novel steps owing to the energy-level splitting caused by dot-MBS coupling. The magnitude of these steps increases with the strength of dot-MBS coupling λ but decreases with the strength of MBS-MBS coupling. The steps shift toward the large ∣eV∣ region as λ or ɛM increases. In addition, dot-MBS coupling enhances the shot noise while MBS-MBS coupling suppresses the shot noise. In the absence of MBS-MBS coupling, a sharp jump emerges in the curve of the Fano factor at zero bias owing to the differential conductance being reduced by a factor of 1/2. This provides a novel technique for the detection of Majorana fermions.

  20. Shot noise in a quantum dot system coupled with Majorana bound states.

    PubMed

    Chen, Qiao; Chen, Ke-Qiu; Zhao, Hong-Kang

    2014-08-01

    We investigate the spectral density of shot noise and current for the system of a quantum dot coupled to Majorana bound states (MBS) employing the nonequilibrium Green's function. The Majorana bound states at the end of the wire strongly affect the shot noise. There are two types of coupling in the system: dot-MBS and MBS-MBS coupling. The curves of shot noise and current versus coupling strength have novel steps owing to the energy-level splitting caused by dot-MBS coupling. The magnitude of these steps increases with the strength of dot-MBS coupling λ but decreases with the strength of MBS-MBS coupling. The steps shift toward the large ∣eV∣ region as λ or ϵ(M) increases. In addition, dot-MBS coupling enhances the shot noise while MBS-MBS coupling suppresses the shot noise. In the absence of MBS-MBS coupling, a sharp jump emerges in the curve of the Fano factor at zero bias owing to the differential conductance being reduced by a factor of 1/2. This provides a novel technique for the detection of Majorana fermions. PMID:25016999

  1. Bound states of Dirac fermions in monolayer gapped graphene in the presence of local perturbations

    NASA Astrophysics Data System (ADS)

    Mohsen, Yarmohammadi; Malek, Zareyan

    2016-06-01

    In graphene, conductance electrons behave as massless relativistic particles and obey an analogue of the Dirac equation in two dimensions with a chiral nature. For this reason, the bounding of electrons in graphene in the form of geometries of quantum dots is impossible. In gapless graphene, due to its unique electronic band structure, there is a minimal conductivity at Dirac points, that is, in the limit of zero doping. This creates a problem for using such a highly motivated new material in electronic devices. One of the ways to overcome this problem is the creation of a band gap in the graphene band structure, which is made by inversion symmetry breaking (symmetry of sublattices). We investigate the confined states of the massless Dirac fermions in an impured graphene by the short-range perturbations for “local chemical potential” and “local gap”. The calculated energy spectrum exhibits quite different features with and without the perturbations. A characteristic equation for bound states (BSs) has been obtained. It is surprisingly found that the relation between the radial functions of sublattices wave functions, i.e., , , and , , can be established by SO(2) group.

  2. Bounded energy states in homogeneous turbulent shear flow: An alternative view

    NASA Technical Reports Server (NTRS)

    Bernard, Peter S.; Speziale, Charles G.

    1990-01-01

    The equilibrium structure of homogeneous turbulent shear flow is investigated from a theoretical standpoint. Existing turbulence models, in apparent agreement with physical and numerical experiments, predict an unbounded exponential time growth of the turbulent kinetic energy and dissipation rate; only the anisotropy tensor and turbulent time scale reach a structural equilibrium. It is shown that if vortex stretching is accounted for in the dissipation rate transport equation, then there can exist equilibrium solutions, with bounded energy states, where the turbulence production is balanced by its dissipation. Illustrative calculations are present for a k-epsilon model modified to account for vortex stretching. The calculations indicate an initial exponential time growth of the turbulent kinetic energy and dissipation rate for elapsed times that are as large as those considered in any of the previously conducted physical or numerical experiments on homogeneous shear flow. However, vortex stretching eventually takes over and forces a production-equals-dissipation equilibrium with bounded energy states. The validity of this result is further supported by an independent theoretical argument. It is concluded that the generally accepted structural equilibrium for homogeneous shear flow with unbounded component energies is in need of re-examination.

  3. Interband type-II miniband-to-bound state diode lasers for the midinfrared

    NASA Astrophysics Data System (ADS)

    Mermelstein, C.; Schmitz, J.; Kiefer, R.; Walther, M.; Wagner, J.

    2004-07-01

    A design for midinfrared diode lasers based on interband type-II miniband-to-bound state transitions is proposed and has been demonstrated experimentally. Type-II miniband-to-bound state laser structures emitting at 3.25μm with active regions consisting of 5 and 10W periods were grown by solid-source molecular-beam epitaxy and processed into ridge waveguide lasers. Substrate-side down mounted devices with a 10 period active region and uncoated facets could be operated in continuous-wave (cw) mode up to 185K and as high as 260K in pulsed mode. A high characteristic temperature of 100K has been achieved for heat-sink temperatures below 140K, decreasing to 33K for the 140 to 185K interval. At 110K, a 5 period laser structure exhibited a threshold current density of 177A/cm2 and a slope efficiency of 61mW /A. Single-ended output powers of 144mW in cw mode and exceeding 330mW in pulsed operation were obtained for a substrate-side down mounted 5 period diode laser with high-reflection/antireflection coated mirror facets, operated at 110K.

  4. Observation of the spatial distribution of gravitationally bound quantum states of ultracold neutrons and its derivation using the Wigner function.

    PubMed

    Ichikawa, G; Komamiya, S; Kamiya, Y; Minami, Y; Tani, M; Geltenbort, P; Yamamura, K; Nagano, M; Sanuki, T; Kawasaki, S; Hino, M; Kitaguchi, M

    2014-02-21

    Ultracold neutrons (UCNs) can be bound by the potential of terrestrial gravity and a reflecting mirror. The wave function of the bound state has characteristic modulations. We carried out an experiment to observe the vertical distribution of the UCNs above such a mirror at the Institut Laue-Langevin in 2011. The observed modulation is in good agreement with that prediction by quantum mechanics using the Wigner function. The spatial resolution of the detector system is estimated to be 0.7  μm. This is the first observation of gravitationally bound states of UCNs with submicron spatial resolution. PMID:24579585

  5. Conserved correlation in PT-symmetric systems: Scattering and bound states

    NASA Astrophysics Data System (ADS)

    Abhinav, Kumar; Jayannavar, Arun; Panigrahi, Prasanta K.

    2013-04-01

    For one-dimensional PT-symmetric systems, it is observed that the non-local product ψ∗(-x,t)ψ(x,t), obtained from the continuity equation can be interpreted as a conserved correlation function. This leads to physical conclusions regarding both discrete and continuum states of such systems. Asymptotic states are shown to have necessarily broken PT-symmetry, leading to modified scattering and transfer matrices. This yields restricted boundary conditions, e.g., incidence from both sides, analogous to that of the proposed PT CPA laser (Longhi, 2010) [4]. The interpretation of 'left' and 'right' states leads to a HermitianS-matrix, resulting in the non-conservation of the 'flux'. This further satisfies a 'duality' condition, identical to the optical analogues (Paasschens et al., 1996) [17]. However, the non-local conserved scalar implements alternate boundary conditions in terms of 'in' and 'out' states, leading to the pseudo-Hermiticity condition in terms of the scattering matrix. Interestingly, when PT-symmetry is preserved, it leads to stationary states with real energy, naturally interpretable as bound states. The broken PT-symmetric phase is also captured by this correlation, with complex-conjugate pair of energies, interpreted as resonances.

  6. Quasi-Bound States of the F·CH4 Complex.

    PubMed

    Schäpers, Daniela; Manthe, Uwe

    2016-05-19

    The F + CH4 → HF + CH3 reaction is an intensively studied prototypical example of a polyatomic reaction showing an early transition state. Prereactive complexes are assumed to play an important role in the dynamics of the reaction. In this work, the long-living resonance states resulting from the formation of a metastable F·CH4 complex are investigated in detail. Full-dimensional quantum dynamics calculations employing the multiconfigurational time-dependent Hartree (MCTDH) approach and a single adiabatic potential energy surface are used to study the low-lying quasi-bound states of the F·CH4 complex for vanishing total (nuclear) angular momentum. The computed dissociation energy of the F·CH4 complex with respect to the reactant asymptote is 170 cm(-1). About 60 resonance states with energies below the reactant asymptote are found. A detailed analysis of the computed wave function of the low-lying states shows an almost free relative rotation of F and CH4 and an approximately separable F-CH4 stretching vibration. The present results are compared with transition state spectroscopy experiments which study the photodetachment spectrum of the CH4F(-) anion. PMID:26730978

  7. Hunt for the 1/sup 1/P/sub 1/ bound state of charmonium

    SciTech Connect

    Porter, F.C.

    1982-02-01

    Using the Crystal Ball detector at SPEAR, we have looked for evidence of the isospin-violating decay psi' ..-->.. ..pi../sup 01/P/sub 1/, where /sup 1/P/sub 1/ is the predicted spin-singlet p-wave bound state of charmonium. For a /sup 1/P/sub 1/ state at the predicted mass (approx. 3520 MeV), we obtain the 95% confidence level limits: BR(psi' ..-->.. ..pi../sup 01/P/sub 1/) < 0.55%, BR(psi' ..-->.. ..pi../sup 01/P/sub 1/)BR(/sup 1/P/sub 1/ ..-->.. ..gamma..n/sub c/ < 0.14%. These limits are compared with simple theoretical predictions.

  8. Formation mechanism of guided resonances and bound states in the continuum in photonic crystal slabs.

    PubMed

    Gao, Xingwei; Hsu, Chia Wei; Zhen, Bo; Lin, Xiao; Joannopoulos, John D; Soljačić, Marin; Chen, Hongsheng

    2016-01-01

    We develop a formalism, based on the mode expansion method, to describe the guided resonances and bound states in the continuum (BICs) in photonic crystal slabs with one-dimensional periodicity. This approach provides analytic insights to the formation mechanisms of these states: the guided resonances arise from the transverse Fabry-Pérot condition, and the divergence of the resonance lifetimes at the BICs is explained by a destructive interference of radiation from different propagating components inside the slab. We show BICs at the center and on the edge of the Brillouin zone protected by symmetry, BICs at generic wave vectors not protected by symmetry, and the annihilation of BICs at low-symmetry wave vectors. PMID:27557882

  9. Catching the bound states in the continuum of a phantom atom in graphene

    NASA Astrophysics Data System (ADS)

    Guessi, L. H.; Machado, R. S.; Marques, Y.; Ricco, L. S.; Kristinsson, K.; Yoshida, M.; Shelykh, I. A.; de Souza, M.; Seridonio, A. C.

    2015-07-01

    We explore theoretically the formation of bound states in the continuum (BICs) in graphene hosting two collinear adatoms situated at different sides of the sheet and at the center of the hexagonal cell, where a phantom atom of a fictitious lattice emulates the six carbons of the cell. We verify that in this configuration the local density of states near the Dirac points exhibits two characteristic features: (i) a cubic dependence on energy instead of a linear one for graphene as found in New J. Phys. 16, 013045 (2014), 10.1088/1367-2630/16/1/013045, and (ii) the formation of BICs as an aftermath of a Fano destructive interference assisted by the Coulomb correlations in the adatoms. For the geometry where adatoms are collinear to carbon atoms, we report an absence of BICs.

  10. Kinesin-8 Is a Low-Force Motor Protein with a Weakly Bound Slip State

    PubMed Central

    Jannasch, Anita; Bormuth, Volker; Storch, Marko; Howard, Jonathon; Schäffer, Erik

    2013-01-01

    During the cell cycle, kinesin-8s control the length of microtubules by interacting with their plus ends. To reach these ends, the motors have to be able to take many steps without dissociating. However, the underlying mechanism for this high processivity and how stepping is affected by force are unclear. Here, we tracked the motion of yeast (Kip3) and human (Kif18A) kinesin-8s with high precision under varying loads using optical tweezers. Surprisingly, both kinesin-8 motors were much weaker compared with other kinesins. Furthermore, we discovered a force-induced stick-slip motion: the motor frequently slipped, recovered from this state, and then resumed normal stepping motility without detaching from the microtubule. The low forces are consistent with kinesin-8s being regulators of microtubule dynamics rather than cargo transporters. The weakly bound slip state, reminiscent of a molecular safety leash, may be an adaptation for high processivity. PMID:23746518

  11. Formation mechanism of guided resonances and bound states in the continuum in photonic crystal slabs

    PubMed Central

    Gao, Xingwei; Hsu, Chia Wei; Zhen, Bo; Lin, Xiao; Joannopoulos, John D.; Soljačić, Marin; Chen, Hongsheng

    2016-01-01

    We develop a formalism, based on the mode expansion method, to describe the guided resonances and bound states in the continuum (BICs) in photonic crystal slabs with one-dimensional periodicity. This approach provides analytic insights to the formation mechanisms of these states: the guided resonances arise from the transverse Fabry–Pérot condition, and the divergence of the resonance lifetimes at the BICs is explained by a destructive interference of radiation from different propagating components inside the slab. We show BICs at the center and on the edge of the Brillouin zone protected by symmetry, BICs at generic wave vectors not protected by symmetry, and the annihilation of BICs at low-symmetry wave vectors. PMID:27557882

  12. Friedel phase discontinuity and bound states in the continuum in quantum dot systems

    NASA Astrophysics Data System (ADS)

    Solís, B.; Ladrón de Guevara, M. L.; Orellana, P. A.

    2008-06-01

    In this Letter we study the Friedel phase of the electron transport in two different systems of quantum dots which exhibit bound states in the continuum (BIC). The Friedel phase jumps abruptly in the energies of the BICs, which is associated to the vanishing width of these states, as shown by Friedrich and Wintgen in [H. Friedrich, D. Wintgen, Phys. Rev. A 31 (1985) 3964]. This odd behavior of the Friedel phase has consequences in the charge through the Friedel sum rule. Namely, if the energy of the BIC drops under the Fermi energy the charge changes abruptly in a unity. We show that this behavior closely relates to discontinuities in the conductance predicted for interacting quantum dot systems.

  13. Andreev bound states and current-phase relations in three-dimensional topological insulators

    NASA Astrophysics Data System (ADS)

    Snelder, M.; Veldhorst, M.; Golubov, A. A.; Brinkman, A.

    2013-03-01

    To guide the search for the Majorana fermion, we theoretically study superconductor/topological-insulator/superconductor (S/TI/S) junctions in an experimentally relevant regime. We find that the striking features present in these systems, including the doubled periodicity of the Andreev bound states (ABSs) due to tunneling via Majorana states, can still be present at high electron densities. We show that via the inclusion of magnetic layers, this 4π periodic ABS can still be observed in three-dimensional (3D) topological insulators, where finite angle incidence usually results in the opening of a gap at zero energy and hence results in a 2π periodic ABS. Furthermore, we study the Josephson-junction characteristics and find that the gap size can be controlled and decreased by tuning the magnetization direction and amplitude. These findings pave the way for designing experiments on S/3DTI/S junctions.

  14. Coronal Mass Ejections and Magnetic Clouds Modeled as MHD Bounded States

    NASA Astrophysics Data System (ADS)

    Fainberg, J.; Osherovich, V. A.

    2004-12-01

    Multiple loops can be seen in the solar corona before the onset of a coronal mass ejection (CME), during and after the event. We apply multi-toroidal configurations to model CMEs and their interplanetary counterparts - magnetic clouds. In the laboratory, plasma confinement is often achieved by conducting metal walls which introduce elastic forces to maintain equilibrium. Such walls, carrying electric surface currents, usually are taken as boundaries where the magnetic field is truncated to provide finite energy for the configuration. The idea of MHD bounded states as solutions with continuous magnetic field and finite magnetic energy was put forward in 1975 [1]. Such solutions describe a single toroid (ground state) and multiple toroids (excited states) [1],[2]. We analyze noncircular cross sections of such toroids and compare the components of the magnetic field vector with in situ observations in interplanetary magnetic clouds. We present Ulysses spacecraft observations in support of our multi-tube model for interplanetary magnetic clouds based on bounded state MHD configurations with axial and helical symmetry [3],[4]. The interaction of CMEs with the global coronal field will also be discussed. In our presentation, we stress the difference in boundary conditions for magnetic configurations in laboratory and space plasmas. [1] Osherovich, V.A., `On an equilibrium of an MHD config-uration with axial symmetry 1', Soln Dann, 5, p. 70, 1975. [2] Osherovich, V.A. and Lawrence, J.K., `Elaboration of the new magnetohydrostatic sunspot theory (Double return flux model)', Sol. Phys., 88, p. 117, 1983. [3] Krat, V.A. and Osherovich, V.A., `Note on the asymmetry of bipolar sunspot groups', Solar Phys., 59, pp. 43-47, 1978. [4] Osherovich, V.A., Fainberg, J. and Stone, R.G., `Multi-tube model for interplanetary magnetic clouds', Geophys. Res. L., 26(3), pp. 401-404, 1999.

  15. Evidencing `Tight Bound States' in the Hydrogen Atom:. Empirical Manipulation of Large-Scale XD in Violation of QED

    NASA Astrophysics Data System (ADS)

    Amoroso, Richard L.; Vigier, Jean-Pierre

    2013-09-01

    In this work we extend Vigier's recent theory of `tight bound state' (TBS) physics and propose empirical protocols to test not only for their putative existence, but also that their existence if demonstrated provides the 1st empirical evidence of string theory because it occurs in the context of large-scale extra dimensionality (LSXD) cast in a unique M-Theoretic vacuum corresponding to the new Holographic Anthropic Multiverse (HAM) cosmological paradigm. Physicists generally consider spacetime as a stochastic foam containing a zero-point field (ZPF) from which virtual particles restricted by the quantum uncertainty principle (to the Planck time) wink in and out of existence. According to the extended de Broglie-Bohm-Vigier causal stochastic interpretation of quantum theory spacetime and the matter embedded within it is created annihilated and recreated as a virtual locus of reality with a continuous quantum evolution (de Broglie matter waves) governed by a pilot wave - a `super quantum potential' extended in HAM cosmology to be synonymous with the a `force of coherence' inherent in the Unified Field, UF. We consider this backcloth to be a covariant polarized vacuum of the (generally ignored by contemporary physicists) Dirac type. We discuss open questions of the physics of point particles (fermionic nilpotent singularities). We propose a new set of experiments to test for TBS in a Dirac covariant polarized vacuum LSXD hyperspace suggestive of a recently tested special case of the Lorentz Transformation put forth by Kowalski and Vigier. These protocols reach far beyond the recent battery of atomic spectral violations of QED performed through NIST.

  16. An upper bound on the second order asymptotic expansion for the quantum communication cost of state redistribution

    NASA Astrophysics Data System (ADS)

    Datta, Nilanjana; Hsieh, Min-Hsiu; Oppenheim, Jonathan

    2016-05-01

    State redistribution is the protocol in which given an arbitrary tripartite quantum state, with two of the subsystems initially being with Alice and one being with Bob, the goal is for Alice to send one of her subsystems to Bob, possibly with the help of prior shared entanglement. We derive an upper bound on the second order asymptotic expansion for the quantum communication cost of achieving state redistribution with a given finite accuracy. In proving our result, we also obtain an upper bound on the quantum communication cost of this protocol in the one-shot setting, by using the protocol of coherent state merging as a primitive.

  17. Estimation of Relative Protein-RNA Binding Strengths from Fluctuations in the Bound State.

    PubMed

    Ghaemi, Zhaleh; Guzman, Irisbel; Baek, Jung-Un Julia; Gruebele, Martin; Luthey-Schulten, Zaida

    2016-09-13

    Protein-RNA complexes are increasingly important in our understanding of cell signaling, metabolism, and transcription. Electrostatic interactions play dominant role in stabilizing such complexes. Using conventional computational approaches, very long simulations of both bound and unbound states are required to obtain accurate estimates of complex dissociation constants (Kd). Here, we derive a simple formula that offers an alternative approach based on the theory of fluctuations. Our method extracts a strong correlate to experimental Kd values using short molecular dynamics simulations of the bound complex only. To test our method, we compared the computed relative Kd values to our experimentally measured values for the U1A-Stem Loop 2 (SL2) RNA complex, which is one of the most-studied protein-RNA complexes. Additionally we also included several experimental values from the literature, to enlarge the data set. We obtain a correlation of r = 0.93 between theoretical and measured estimates of Kd values of the mutated U1A protein-RNA complexes relative to the wild type dissociation constant. The proposed method increases the efficiency of relative Kd values estimation for multiple protein mutants, allowing its applicability to protein engineering projects. PMID:27529183

  18. Rovibrational bound states of neon trimer: quantum dynamical calculation of all eigenstate energy levels and wavefunctions.

    PubMed

    Yang, Benhui; Chen, Wenwu; Poirier, Bill

    2011-09-01

    Exact quantum dynamics calculations of the eigenstate energy levels and wavefunctions for all bound rovibrational states of the Ne(3) trimer (J = 0-18) have been performed using the ScalIT suite of parallel codes. These codes employ a combination of highly efficient methods, including phase-space optimized discrete variable representation, optimal separable basis, and preconditioned inexact spectral transform methods, together with an effective massive parallelization scheme. The Ne(3) energy levels and wavefunctions were computed using a pair-wise Lennard-Jones potential. Jacobi coordinates were used for the calculations, but to identify just those states belonging to the totally symmetric irreducible representation of the G(12) complete nuclear permutation-inversion group, wavefunctions were plotted in hyperspherical coordinates. "Horseshoe" states were observed above the isomerization barrier, but the horseshoe localization effect is weaker than in Ar(3). The rigid rotor model is found to be applicable for only the ground and first excited vibrational states at low J; fitted rotational constant values are presented. PMID:21913762

  19. Attosecond transient absorption probing of electronic superpositions of bound states in neon. Detection of quantum beats

    DOE PAGESBeta

    Beck, Annelise R; Bernhardt, Birgitta; Warrick, Erika R.; Wu, Mengxi; Chen, Shaohao; Gaarde, Mette B.; Schafer, Kenneth J.; Neumark, Daniel M.; Leone, Stephen R.

    2014-11-07

    Electronic wavepackets composed of multiple bound excited states of atomic neon lying between 19.6 and 21.5 eV are launched using an isolated attosecond pulse. Individual quantum beats of the wavepacket are detected by perturbing the induced polarization of the medium with a time-delayed few-femtosecond near-infrared (NIR) pulse via coupling the individual states to multiple neighboring levels. All of the initially excited states are monitored simultaneously in the attosecond transient absorption spectrum, revealing Lorentzian to Fano lineshape spectral changes as well as quantum beats. The most prominent beating of the several that were observed was in the spin–orbit split 3d absorptionmore » features, which has a 40 femtosecond period that corresponds to the spin–orbit splitting of 0.1 eV. The few-level models and multilevel calculations confirm that the observed magnitude of oscillation depends strongly on the spectral bandwidth and tuning of the NIR pulse and on the location of possible coupling states.« less

  20. Attosecond transient absorption probing of electronic superpositions of bound states in neon. Detection of quantum beats

    SciTech Connect

    Beck, Annelise R; Bernhardt, Birgitta; Warrick, Erika R.; Wu, Mengxi; Chen, Shaohao; Gaarde, Mette B.; Schafer, Kenneth J.; Neumark, Daniel M.; Leone, Stephen R.

    2014-11-07

    Electronic wavepackets composed of multiple bound excited states of atomic neon lying between 19.6 and 21.5 eV are launched using an isolated attosecond pulse. Individual quantum beats of the wavepacket are detected by perturbing the induced polarization of the medium with a time-delayed few-femtosecond near-infrared (NIR) pulse via coupling the individual states to multiple neighboring levels. All of the initially excited states are monitored simultaneously in the attosecond transient absorption spectrum, revealing Lorentzian to Fano lineshape spectral changes as well as quantum beats. The most prominent beating of the several that were observed was in the spin–orbit split 3d absorption features, which has a 40 femtosecond period that corresponds to the spin–orbit splitting of 0.1 eV. The few-level models and multilevel calculations confirm that the observed magnitude of oscillation depends strongly on the spectral bandwidth and tuning of the NIR pulse and on the location of possible coupling states.

  1. Structural Model of the R State of Escherichia coli Aspartate Transcarbamoylase with Substrates Bound

    PubMed Central

    Wang, Jie; Eldo, Joby; Kantrowitz, Evan R.

    2009-01-01

    The allosteric enzyme aspartate transcarbamoylase (ATCase) exists in two conformational states. The enzyme, in the absence of substrates is primarily in the low-activity T state, is converted to the high-activity R state upon substrate binding, and remains in the R state until substrates are exhausted. These conformational changes have made it difficult to obtain structural data on R-state active-site complexes. Here we report the R-state structure of ATCase with the substrate Asp and the substrate analogue phosphonactamide (PAM) bound. This R-state structure represents the stage in the catalytic mechanism immediately before the formation of the covalent bond between the nitrogen of the amino group of Asp and the carbonyl carbon of carbamoyl phosphate. The binding mode of the PAM is similar to the binding mode of the phosphonate moiety of N-(phosphonoacetyl)-L-aspartate (PALA), the carboxylates of Asp interact with the same residues that interact with the carboxylates of PALA, although the position and orientations are shifted. The amino group of Asp is 2.9 Å away from the carbonyl oxygen of PAM, positioned correctly for the nucleophilic attack. Arg105 and Leu267 in the catalytic chain interact with PAM and Asp and help to position the substrates correctly for catalysis. This structure fills a key gap in the structural determination of each of the steps in the catalytic cycle. By combining these data with previously determined structures we can now visualize the allosteric transition through detailed atomic motions that underlie the molecular mechanism. PMID:17603076

  2. Structural Model of the R State of Escherichia coli Aspartate Transcarbamoylase with Substrates Bound

    SciTech Connect

    Wang,J.; Eldo, J.; Kantrowitz, E.

    2007-01-01

    The allosteric enzyme aspartate transcarbamoylase (ATCase) exists in two conformational states. The enzyme, in the absence of substrates is primarily in the low-activity T state, is converted to the high-activity R state upon substrate binding, and remains in the R state until substrates are exhausted. These conformational changes have made it difficult to obtain structural data on R-state active-site complexes. Here we report the R-state structure of ATCase with the substrate Asp and the substrate analog phosphonoactamide (PAM) bound. This R-state structure represents the stage in the catalytic mechanism immediately before the formation of the covalent bond between the nitrogen of the amino group of Asp and the carbonyl carbon of carbamoyl phosphate. The binding mode of the PAM is similar to the binding mode of the phosphonate moiety of N-(phosphonoacetyl)-l-aspartate (PALA), the carboxylates of Asp interact with the same residues that interact with the carboxylates of PALA, although the position and orientations are shifted. The amino group of Asp is 2.9 {angstrom} away from the carbonyl oxygen of PAM, positioned correctly for the nucleophilic attack. Arg105 and Leu267 in the catalytic chain interact with PAM and Asp and help to position the substrates correctly for catalysis. This structure fills a key gap in the structural determination of each of the steps in the catalytic cycle. By combining these data with previously determined structures we can now visualize the allosteric transition through detailed atomic motions that underlie the molecular mechanism.

  3. Potential energy surface and bound states of the NH3-Ar and ND3-Ar complexes.

    PubMed

    Loreau, J; Liévin, J; Scribano, Y; van der Avoird, A

    2014-12-14

    A new, four-dimensional potential energy surface for the interaction of NH3 and ND3 with Ar is computed using the coupled-cluster method with single, double, and perturbative triple excitations and large basis sets. The umbrella motion of the ammonia molecule is explicitly taken into account. The bound states of both NH3-Ar and ND3-Ar are calculated on this potential for total angular momentum values from J = 0 to 10, with the inclusion of Coriolis interactions. The energies and splittings of the rovibrational levels are in excellent agreement with the extensive high-resolution spectroscopic data accumulated over the years in the infrared and microwave regions for both complexes, which demonstrates the quality of the potential energy surface. PMID:25494745

  4. Two-magnon bound state causes ultrafast thermally induced magnetisation switching

    PubMed Central

    Barker, J.; Atxitia, U.; Ostler, T. A.; Hovorka, O.; Chubykalo-Fesenko, O.; Chantrell, R. W.

    2013-01-01

    There has been much interest recently in the discovery of thermally induced magnetisation switching using femtosecond laser excitation, where a ferrimagnetic system can be switched deterministically without an applied magnetic field. Experimental results suggest that the reversal occurs due to intrinsic material properties, but so far the microscopic mechanism responsible for reversal has not been identified. Using computational and analytic methods we show that the switching is caused by the excitation of two-magnon bound states, the properties of which are dependent on material factors. This discovery allows us to accurately predict the onset of switching and the identification of this mechanism will allow new classes of materials to be identified or designed for memory devices in the THz regime. PMID:24253110

  5. Structural Diversity in Free and Bound States of Intrinsically Disordered Protein Phosphatase 1 Regulators

    SciTech Connect

    Marsh, J.A.; Allaire, M.; Dancheck, B.; Ragusa, M.J.; Forman-Kay, J.D.; Peti, Wolfgang

    2010-09-08

    Complete folding is not a prerequisite for protein function, as disordered and partially folded states of proteins frequently perform essential biological functions. In order to understand their functions at the molecular level, we utilized diverse experimental measurements to calculate ensemble models of three nonhomologous, intrinsically disordered proteins: I-2, spinophilin, and DARPP-32, which bind to and regulate protein phosphatase 1 (PP1). The models demonstrate that these proteins have dissimilar propensities for secondary and tertiary structure in their unbound forms. Direct comparison of these ensemble models with recently determined PP1 complex structures suggests a significant role for transient, preformed structure in the interactions of these proteins with PP1. Finally, we generated an ensemble model of partially disordered I-2 bound to PP1 that provides insight into the relationship between flexibility and biological function in this dynamic complex.

  6. Remarkable coincidence for the top Yukawa coupling and an approximately massless bound state

    SciTech Connect

    Froggatt, C. D.; Nielsen, H. B.

    2009-08-01

    We calculate, with several corrections, the nonrelativistic binding by Higgs exchange and gluon exchange between six top and six antitop quarks (actually replaced by left-handed b quarks from time to time). The remarkable result is that, within our calculational accuracy of the order of 14% in the top-quark Yukawa coupling g{sub t}, the experimental running top-quark Yukawa coupling g{sub t}=0.935 happens to have just that value which gives a perfect cancellation of the unbound mass=12 top-quark masses by this binding energy. In other words the bound state is massless to the accuracy of our calculation. Our calculation is in disagreement with a similar calculation by Kuchiev et al., but this deviation may be explained by a phase transition. We and Kuchiev et al. compute on different sides of this phase transition.

  7. Observation of excitonic N-body bound states: polyexcitons in diamond.

    PubMed

    Omachi, J; Suzuki, T; Kato, K; Naka, N; Yoshioka, K; Kuwata-Gonokami, M

    2013-07-12

    We have found a series of resonances associated with the bound state (polyexcitons, PE(N)s) of N excitons up to N=6 in the emission spectra of diamond under two-photon excitation at around 10 K. Time-resolved spectra show a stepwise formation of PE(N)s with smaller to larger N, as well as a successive decay from larger to smaller N. At higher excitation levels, the transformation of PE(N)s into a condensed phase of electron-hole droplets occurs. The binding energies of the PE(N)s, normalized to the exciton Rydberg energy, agree well with those of silicon, suggesting the universality of the phenomena. PMID:23889423

  8. Inverting the Nakanishi Integral Relation for a Bound State Euclidean Bethe-Salpeter Amplitude

    NASA Astrophysics Data System (ADS)

    Frederico, T.; Carbonell, J.; Gigante, V.; Karmanov, V. A.

    2016-07-01

    The extraction of the weight function g of the Nakanishi integral representation of the Bethe-Salpeter amplitude is investigated. We studied the numerical inversion of the discretized Nakanishi kernel in the case of an Euclidean bound state. The discretized kernel is regularized by adding the identity operator times a small regularisation parameter {\\varepsilon} to avoid numerically unstabilities. We have found that the weight function g as well as the associated light-front valence wave function are unstable against variation of {\\varepsilon}. These results suggest that the extraction of the Nakanishi weight function from an Euclidean amplitude, is an ill-defined problem. Without further assumptions on the solution or/and without developing more elaborate methods, the Nakanishi weight function, as well as the corresponding light-front valence wave function, cannot be safely determined.

  9. Transport through Andreev Bound States in a Graphene-base Quantum Dot

    NASA Astrophysics Data System (ADS)

    Li, Yanjing; Mason, Nadya

    2012-02-01

    We perform tunneling spectroscopy on a graphene-quantum dot (QD)-superconductor junction, a system in which sharp, gate-tunable Andreev bound states (ABS) in the spectra have been observed [1]. Here we extend previous results, particularly regarding the origins of the QD. In particular, we discuss how a discontinuous layer of AlOx between the superconductor and the graphene plays a role in the formation of the QD. We also discuss additional spectroscopic features that may be due to multiple QDs and energy levels. Finally, we show that a robust superconducting tunneling junction can be created in a lead-graphene structure, without the explicit deposition of a tunneling barrier. [4pt] [1] Dirks, T., Nature Physics 7, 386--390 (2011)

  10. Inverting the Nakanishi Integral Relation for a Bound State Euclidean Bethe-Salpeter Amplitude

    NASA Astrophysics Data System (ADS)

    Frederico, T.; Carbonell, J.; Gigante, V.; Karmanov, V. A.

    2016-03-01

    The extraction of the weight function g of the Nakanishi integral representation of the Bethe-Salpeter amplitude is investigated. We studied the numerical inversion of the discretized Nakanishi kernel in the case of an Euclidean bound state. The discretized kernel is regularized by adding the identity operator times a small regularisation parameter {\\varepsilon} to avoid numerically unstabilities. We have found that the weight function g as well as the associated light-front valence wave function are unstable against variation of {\\varepsilon} . These results suggest that the extraction of the Nakanishi weight function from an Euclidean amplitude, is an ill-defined problem. Without further assumptions on the solution or/and without developing more elaborate methods, the Nakanishi weight function, as well as the corresponding light-front valence wave function, cannot be safely determined.

  11. Detecting the Exchange Phase of Majorana Bound States in a Corbino Geometry Topological Josephson Junction.

    PubMed

    Park, Sunghun; Recher, Patrik

    2015-12-11

    A phase from an adiabatic exchange of Majorana bound states (MBS) reveals their exotic anyonic nature. For detecting this exchange phase, we propose an experimental setup consisting of a Corbino geometry Josephson junction on the surface of a topological insulator, in which two MBS at zero energy can be created and rotated. We find that if a metallic tip is weakly coupled to a point on the junction, the time-averaged differential conductance of the tip-Majorana coupling shows peaks at the tip voltages eV=±(α-2πl)ℏ/T_{J}, where α=π/2 is the exchange phase of the two circulating MBS, T_{J} is the half rotation time of MBS, and l an integer. This result constitutes a clear experimental signature of Majorana fermion exchange. PMID:26705644

  12. Solution of two-body relativistic bound state equations with confining plus Coulomb interactions

    NASA Technical Reports Server (NTRS)

    Maung, Khin Maung; Kahana, David E.; Norbury, John W.

    1992-01-01

    Studies of meson spectroscopy have often employed a nonrelativistic Coulomb plus Linear Confining potential in position space. However, because the quarks in mesons move at an appreciable fraction of the speed of light, it is necessary to use a relativistic treatment of the bound state problem. Such a treatment is most easily carried out in momentum space. However, the position space Linear and Coulomb potentials lead to singular kernels in momentum space. Using a subtraction procedure we show how to remove these singularities exactly and thereby solve the Schroedinger equation in momentum space for all partial waves. Furthermore, we generalize the Linear and Coulomb potentials to relativistic kernels in four dimensional momentum space. Again we use a subtraction procedure to remove the relativistic singularities exactly for all partial waves. This enables us to solve three dimensional reductions of the Bethe-Salpeter equation. We solve six such equations for Coulomb plus Confining interactions for all partial waves.

  13. Detecting the Exchange Phase of Majorana Bound States in a Corbino Geometry Topological Josephson Junction

    NASA Astrophysics Data System (ADS)

    Park, Sunghun; Recher, Patrik

    2015-12-01

    A phase from an adiabatic exchange of Majorana bound states (MBS) reveals their exotic anyonic nature. For detecting this exchange phase, we propose an experimental setup consisting of a Corbino geometry Josephson junction on the surface of a topological insulator, in which two MBS at zero energy can be created and rotated. We find that if a metallic tip is weakly coupled to a point on the junction, the time-averaged differential conductance of the tip-Majorana coupling shows peaks at the tip voltages e V =±(α -2 π l )ℏ/TJ, where α =π /2 is the exchange phase of the two circulating MBS, TJ is the half rotation time of MBS, and l an integer. This result constitutes a clear experimental signature of Majorana fermion exchange.

  14. Bounds on the density of states of random Schrödinger operators

    NASA Astrophysics Data System (ADS)

    Maier, Robert S.

    1987-08-01

    Bounds are obtained on the unintegrated density of states ρ( E) of random Schrödinger operators H=-Δ + V acting on L 2(ℝ d ) or l 2(ℤ d ). In both cases the random potential is V: = sumlimits_{y in {Z}^d } {V_y χ (Λ (y))} in which the\\{ {V_y } \\}_{y in {Z}^d } are IID random variables with density f. The χ denotes indicator function, and in the continuum case the\\{ {Λ (y)} \\}_{y in {Z}^d } are cells of unit dimensions centered on y∈ℤ d . In the finite-difference case Λ( y) denotes the site y∈ℤ d itself. Under the assumption f ∈ L {0/1+ɛ}(ℝ) it is proven that in the finitedifference case p ∈ L ∞(ℝ), and that in the d= 1 continuum case p ∈ L {loc/∞}(ℝ).

  15. In-situ material state monitoring using embedded CdSe quantum dots

    NASA Astrophysics Data System (ADS)

    Brubaker, Cole D.; Frecker, Talitha M.; Njoroge, Ian; Shane, Dylan O.; Smudde, Christine M.; Rosenthal, Sandra J.; Jennings, G. Kane; Adams, Douglas E.

    2016-04-01

    The development of new, smart materials capable of intrinsically detecting and communicating the occurrence of external loads and resultant damage present in a material will be crucial in the advancement of future structural health monitoring (SHM) and nondestructive evaluation (NDE) technologies. Traditionally, many SHM and NDE approaches have relied on the use of physical sensors to monitor a structure for damage, but are often hindered by their requirements for power consumption and large-scale data collection. In this work, we seek to evaluate the effectiveness of ultrasmall, white-light emitting Cadmium Selenide quantum dots (CdSe QDs) as an alternative to providing in-situ material state monitoring capabilities, while also aiming to reduce reliance on data collection and power consumption to effectively monitor a material and structure for damage. To achieve this goal, CdSe QDs are embedded in an optically clear epoxy composite matrix and exposed to external mechanical loadings. Initial results show a corresponding relationship between the shifts in observed emission spectra and external load for samples containing CdSe QDs. The effectiveness of CdSe QDs as a surface strain gauge on aluminum and fiberglass are also investigated in this paper. By monitoring changes in the emission spectra for materials containing CdSe QDs before, during and after the application of external loads, the effectiveness of CdSe QDs for communicating the occurrence of external loads acting on a material and detecting changes in material state is evaluated.

  16. A search for ϕ meson nucleus bound state using antiproton annihilation on nucleus

    NASA Astrophysics Data System (ADS)

    Ohnishi, H.; Bühler, P.; Cargnelli, M.; Curceanu, C.; Guaraldo, C.; Hartmann, O.; Hicks, K.; Iwasaki, M.; Ishiwatari, T.; Kienle, P.; Marton, J.; Muto, R.; Naruki, M.; Niiyama, M.; Noumi, H.; Okada, S.; Vidal, A. Romero; Sakaguchi, A.; Sakuma, F.; Sawada, S.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Tsukada, K.; Doce, O. Vazquez; Widmann, E.; Yokkaichi, S.; Zmeskal, J.

    The mass shift of the vector mesons in nuclei is known to be a powerful tool for investigating the mechanism of generating hadron mass from the QCD vacuum. The mechanism is known to be the spontaneous breaking of chiral symmetry. In 2007, KEK-PS E325 experiment reported about 3.4 % mass reduction of the ϕ meson in medium-heavy nuclei (Cu). This result is possibly one of the indications of the partial restoration of chiral symmetry in nuclei, however, unfortunately it is hard to make strong conclusions from the data. One of the ways to conclude the strength of the ϕ meson mass shift in nuclei will be by trying to produce only slowly moving ϕ mesons where the maximum nuclear matter effect can be probed. The observed mass reduction of the ϕ meson in the nucleus can be translated as the existence of an attractive force between ϕ meson and nucleus. Thus, one of the extreme conditions that can be achieved in the laboratory is indeed the formation of a ϕ-nucleus bound state, where the ϕ meson is "trapped" in the nucleus. The purpose of the experiment is to search for a ϕ-nucleus bound state and measure the binding energy of the system. We will demonstrate that a completely background-free missing-mass spectrum can be obtained efficiently by (bar{p}, φ) spectroscopy together with K + Λ tagging, using the primary reaction channel bar{p} p rightarrow φ φ. This paper gives an overview of the physics motivation and the detector concept, and explains the direction of the initial research and development effort.

  17. A search for ϕ meson nucleus bound state using antiproton annihilation on nucleus

    NASA Astrophysics Data System (ADS)

    Ohnishi, H.; Bühler, P.; Cargnelli, M.; Curceanu, C.; Guaraldo, C.; Hartmann, O.; Hicks, K.; Iwasaki, M.; Ishiwatari, T.; Kienle, P.; Marton, J.; Muto, R.; Naruki, M.; Niiyama, M.; Noumi, H.; Okada, S.; Vidal, A. Romero; Sakaguchi, A.; Sakuma, F.; Sawada, S.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Tsukada, K.; Doce, O. Vazquez; Widmann, E.; Yokkaichi, S.; Zmeskal, J.

    2012-12-01

    The mass shift of the vector mesons in nuclei is known to be a powerful tool for investigating the mechanism of generating hadron mass from the QCD vacuum. The mechanism is known to be the spontaneous breaking of chiral symmetry. In 2007, KEK-PS E325 experiment reported about 3.4 % mass reduction of the ϕ meson in medium-heavy nuclei (Cu). This result is possibly one of the indications of the partial restoration of chiral symmetry in nuclei, however, unfortunately it is hard to make strong conclusions from the data. One of the ways to conclude the strength of the ϕ meson mass shift in nuclei will be by trying to produce only slowly moving ϕ mesons where the maximum nuclear matter effect can be probed. The observed mass reduction of the ϕ meson in the nucleus can be translated as the existence of an attractive force between ϕ meson and nucleus. Thus, one of the extreme conditions that can be achieved in the laboratory is indeed the formation of a ϕ-nucleus bound state, where the ϕ meson is "trapped" in the nucleus. The purpose of the experiment is to search for a ϕ-nucleus bound state and measure the binding energy of the system. We will demonstrate that a completely background-free missing-mass spectrum can be obtained efficiently by (bar{p}, φ) spectroscopy together with K + Λ tagging, using the primary reaction channel bar{p} p rightarrow φ φ. This paper gives an overview of the physics motivation and the detector concept, and explains the direction of the initial research and development effort.

  18. Majorana bound state of a Bogoliubov-de Gennes-Dirac Hamiltonian in arbitrary dimensions

    NASA Astrophysics Data System (ADS)

    Imura, Ken-Ichiro; Fukui, Takahiro; Fujiwara, Takanori

    2012-01-01

    We study a Majorana zero-energy state bound to a hedgehog-like point defect in a topological superconductor described by a Bogoliubov-de Gennes (BdG)-Dirac type effective Hamiltonian. We first give an explicit wave function of a Majorana state by solving the BdG equation directly, from which an analytical index can be obtained. Next, by calculating the corresponding topological index, we show a precise equivalence between both indices to confirm the index theorem. Finally, we apply this observation to reexamine the role of another topological invariant, i.e., the Chern number associated with the Berry curvature proposed in the study of protected zero modes along the lines of topological classification of insulators and superconductors. We show that the Chern number is equivalent to the topological index, implying that it indeed reflects the number of zero-energy states. Our theoretical model belongs to the BDI class from the viewpoint of symmetry, whereas the spatial dimension d of the system is left arbitrary throughout the paper.

  19. Dynamical study of the X(3915) as a D*D* bound state in a quark model

    SciTech Connect

    Yang Youchang; Ping Jialun

    2010-06-01

    Considering the coupling of color 1 x 1 and 8 x 8 structures, we calculate the energy of the newly observed X(3915) as an S-wave D*D* state in the Bhaduri, Cohler, and Nogami quark model by the Gaussian expansion method. Because of the color coupling, the bound state of D*D* with J{sup PC}=0{sup ++} is found, which is well consonant with the experimental data of the X(3915). The bound states of B*B* with J{sup PC}=0{sup ++} and 2{sup ++} are also predicted in this work.

  20. Communication: Observation of dipole-bound state and high-resolution photoelectron imaging of cold acetate anions

    SciTech Connect

    Huang, Dao-Ling; Zhu, Guo-Zhu; Wang, Lai-Sheng

    2015-03-07

    We report the observation of a dipole-bound state and a high-resolution photoelectron imaging study of cryogenically cooled acetate anions (CH{sub 3}COO{sup −}). Both high-resolution non-resonant and resonant photoelectron spectra via the dipole-bound state of CH{sub 3}COO{sup −} are obtained. The binding energy of the dipole-bound state relative to the detachment threshold is determined to be 53 ± 8 cm{sup −1}. The electron affinity of the CH{sub 3}COO neutral radical is measured accurately as 26 236 ± 8 cm{sup −1} (3.2528 ± 0.0010 eV) using high-resolution photoelectron imaging. This accurate electron affinity is validated by observation of autodetachment from two vibrational levels of the dipole-bound state of CH{sub 3}COO{sup −}. Excitation spectra to the dipole-bound states yield rotational profiles, allowing the rotational temperature of the trapped CH{sub 3}COO{sup −} anions to be evaluated.

  1. Thermodynamic properties of highly frustrated quantum spin ladders: Influence of many-particle bound states

    NASA Astrophysics Data System (ADS)

    Honecker, A.; Wessel, S.; Kerkdyk, R.; Pruschke, T.; Mila, F.; Normand, B.

    2016-02-01

    Quantum antiferromagnets have proven to be some of the cleanest realizations available for theoretical, numerical, and experimental studies of quantum fluctuation effects. At finite temperatures, however, the additional effects of thermal fluctuations in the restricted phase space of a low-dimensional system have received much less attention, particularly the situation in frustrated quantum magnets, where the excitations may be complex collective (bound or even fractionalized) modes. We investigate this problem by studying the thermodynamic properties of the frustrated two-leg S =1/2 spin ladder, with particular emphasis on the fully frustrated case. We present numerical results for the magnetic specific heat and susceptibility, obtained from exact diagonalization and quantum Monte Carlo studies, which we show can be rendered free of the sign problem even in a strongly frustrated system and which allow us to reach unprecedented sizes of L =200 ladder rungs. We find that frustration effects cause an unconventional evolution of the thermodynamic response across the full parameter regime of the model. However, close to the first-order transition they cause a highly anomalous reduction in temperature scales with no concomitant changes in the gap; the specific heat shows a very narrow peak at very low energies and the susceptibility rises abruptly at extremely low temperatures. Unusually, the two quantities have different gaps over an extended region of the parameter space. We demonstrate that these results reflect the presence of large numbers of multiparticle bound-state excitations, whose energies fall below the one-triplon gap in the transition region.

  2. Wave-function frozen-density embedding: Approximate analytical nuclear ground-state gradients.

    PubMed

    Heuser, Johannes; Höfener, Sebastian

    2016-05-01

    We report the derivation of approximate analytical nuclear ground-state uncoupled frozen density embedding (FDEu) gradients for the resolution of identity (RI) variant of the second-order approximate coupled cluster singles and doubles (RICC2) as well as density functional theory (DFT), and an efficient implementation thereof in the KOALA program. In order to guarantee a computationally efficient treatment, those gradient terms are neglected which would require the exchange of orbital information. This approach allows for geometry optimizations of single molecules surrounded by numerous molecules with fixed nuclei at RICC2-in-RICC2, RICC2-in-DFT, and DFT-in-DFT FDE level of theory using a dispersion correction, required due to the DFT-based treatment of the interaction in FDE theory. Accuracy and applicability are assessed by the example of two case studies: (a) the Watson-Crick pair adenine-thymine, for which the optimized structures exhibit a maximum error of about 0.08 Å for our best scheme compared to supermolecular reference calculations, (b) carbon monoxide on a magnesium oxide surface model, for which the error amount up to 0.1 Å for our best scheme. Efficiency is demonstrated by successively including environment molecules and comparing to an optimized conventional supermolecular implementation, showing that the method is able to outperform conventional RICC2 schemes already with a rather small number of environment molecules, gaining significant speed up in computation time. PMID:26804310

  3. Probing Majorana bound states via counting statistics of a single electron transistor

    NASA Astrophysics Data System (ADS)

    Li, Zeng-Zhao; Lam, Chi-Hang; You, J. Q.

    2015-06-01

    We propose an approach for probing Majorana bound states (MBSs) in a nanowire via counting statistics of a nearby charge detector in the form of a single-electron transistor (SET). We consider the impacts on the counting statistics by both the local coupling between the detector and an adjacent MBS at one end of a nanowire and the nonlocal coupling to the MBS at the other end. We show that the Fano factor and the skewness of the SET current are minimized for a symmetric SET configuration in the absence of the MBSs or when coupled to a fermionic state. However, the minimum points of operation are shifted appreciably in the presence of the MBSs to asymmetric SET configurations with a higher tunnel rate at the drain than at the source. This feature persists even when varying the nonlocal coupling and the pairing energy between the two MBSs. We expect that these MBS-induced shifts can be measured experimentally with available technologies and can serve as important signatures of the MBSs.

  4. Probing Majorana bound states via counting statistics of a single electron transistor

    PubMed Central

    Li, Zeng-Zhao; Lam, Chi-Hang; You, J. Q.

    2015-01-01

    We propose an approach for probing Majorana bound states (MBSs) in a nanowire via counting statistics of a nearby charge detector in the form of a single-electron transistor (SET). We consider the impacts on the counting statistics by both the local coupling between the detector and an adjacent MBS at one end of a nanowire and the nonlocal coupling to the MBS at the other end. We show that the Fano factor and the skewness of the SET current are minimized for a symmetric SET configuration in the absence of the MBSs or when coupled to a fermionic state. However, the minimum points of operation are shifted appreciably in the presence of the MBSs to asymmetric SET configurations with a higher tunnel rate at the drain than at the source. This feature persists even when varying the nonlocal coupling and the pairing energy between the two MBSs. We expect that these MBS-induced shifts can be measured experimentally with available technologies and can serve as important signatures of the MBSs. PMID:26098973

  5. Probing Majorana bound states via counting statistics of a single electron transistor.

    PubMed

    Li, Zeng-Zhao; Lam, Chi-Hang; You, J Q

    2015-01-01

    We propose an approach for probing Majorana bound states (MBSs) in a nanowire via counting statistics of a nearby charge detector in the form of a single-electron transistor (SET). We consider the impacts on the counting statistics by both the local coupling between the detector and an adjacent MBS at one end of a nanowire and the nonlocal coupling to the MBS at the other end. We show that the Fano factor and the skewness of the SET current are minimized for a symmetric SET configuration in the absence of the MBSs or when coupled to a fermionic state. However, the minimum points of operation are shifted appreciably in the presence of the MBSs to asymmetric SET configurations with a higher tunnel rate at the drain than at the source. This feature persists even when varying the nonlocal coupling and the pairing energy between the two MBSs. We expect that these MBS-induced shifts can be measured experimentally with available technologies and can serve as important signatures of the MBSs. PMID:26098973

  6. Generation of bound states of pulses in a soliton laser with complex relaxation of a saturable absorber

    NASA Astrophysics Data System (ADS)

    Zolotovskii, I. O.; Korobko, D. A.; Gumenyuk, R. V.; Okhotnikov, O. G.

    2015-01-01

    A numerical model of a soliton fibre laser with a semiconductor saturable absorber mirror (SESAM), characterised by the complex dynamics of absorption relaxation, is considered. It is shown that stationary bound states of pulses can be formed in this laser as a result of their interaction via the dispersion-wave field. The stability of stationary bound states of several pulses is analysed. It is shown that an increase in the number of pulses in a stationary bound state leads eventually to its decay and formation of a random bunch. It is found that the bunch stability is caused by the manifestation of nonlinear self-phase modulation, which attracts pulses to the bunch centre. The simulation results are in qualitative agreement with experimental data.

  7. Harmonic mode locking of bound-state solitons fiber laser based on MoS(2) saturable absorber.

    PubMed

    Wang, Yadong; Mao, Dong; Gan, Xuetao; Han, Lei; Ma, Chaojie; Xi, Teli; Zhang, Yi; Shang, Wuyun; Hua, Shijia; Zhao, Jianlin

    2015-01-12

    We present a kind of harmonic mode locking of bound-state solitons in a fiber laser based on molybdenum disulfide (MoS(2)) saturable absorber (SA). The mode locker is fabricated by depositing MoS(2) nanosheets on a D-shaped fiber (DF). In the fiber laser, two solitons form the bound-state pulses with a temporal separation of 3.4 ps, and the bound-state pulses are equally distributed at a repetition rate of 125 MHz, corresponding to 14th harmonics of fundamental cavity repetition rate (8.968 MHz). Single- and multiple-pulses emissions are also observed by changing the pump power and optimizing the DF based MoS(2) SA. Our experiment demonstrates an interesting operation regime of mode-locked fiber laser, and shows that DF based MoS(2) SA can work as a promising high-power mode locker in ultrafast lasers. PMID:25835667

  8. Generation of bound states of pulses in a soliton laser with complex relaxation of a saturable absorber

    SciTech Connect

    Zolotovskii, I O; Korobko, D A; Okhotnikov, O G; Gumenyuk, R V

    2015-01-31

    A numerical model of a soliton fibre laser with a semiconductor saturable absorber mirror (SESAM), characterised by the complex dynamics of absorption relaxation, is considered. It is shown that stationary bound states of pulses can be formed in this laser as a result of their interaction via the dispersion-wave field. The stability of stationary bound states of several pulses is analysed. It is shown that an increase in the number of pulses in a stationary bound state leads eventually to its decay and formation of a random bunch. It is found that the bunch stability is caused by the manifestation of nonlinear self-phase modulation, which attracts pulses to the bunch centre. The simulation results are in qualitative agreement with experimental data. (nonlinear optical phenomena)

  9. Transient neuronal coactivations embedded in globally propagating waves underlie resting-state functional connectivity.

    PubMed

    Matsui, Teppei; Murakami, Tomonari; Ohki, Kenichi

    2016-06-01

    Resting-state functional connectivity (FC), which measures the correlation of spontaneous hemodynamic signals (HemoS) between brain areas, is widely used to study brain networks noninvasively. It is commonly assumed that spatial patterns of HemoS-based FC (Hemo-FC) reflect large-scale dynamics of underlying neuronal activity. To date, studies of spontaneous neuronal activity cataloged heterogeneous types of events ranging from waves of activity spanning the entire neocortex to flash-like activations of a set of anatomically connected cortical areas. However, it remains unclear how these various types of large-scale dynamics are interrelated. More importantly, whether each type of large-scale dynamics contributes to Hemo-FC has not been explored. Here, we addressed these questions by simultaneously monitoring neuronal calcium signals (CaS) and HemoS in the entire neocortex of mice at high spatiotemporal resolution. We found a significant relationship between two seemingly different types of large-scale spontaneous neuronal activity-namely, global waves propagating across the neocortex and transient coactivations among cortical areas sharing high FC. Different sets of cortical areas, sharing high FC within each set, were coactivated at different timings of the propagating global waves, suggesting that spatial information of cortical network characterized by FC was embedded in the phase of the global waves. Furthermore, we confirmed that such transient coactivations in CaS were indeed converted into spatially similar coactivations in HemoS and were necessary to sustain the spatial structure of Hemo-FC. These results explain how global waves of spontaneous neuronal activity propagating across large-scale cortical network contribute to Hemo-FC in the resting state. PMID:27185944

  10. Evolution of Density of States and a Spin-Resolved Checkerboard-Type Pattern Associated with the Majorana Bound State

    NASA Astrophysics Data System (ADS)

    Kawakami, Takuto; Hu, Xiao

    2015-10-01

    In terms of the Bogoliubov-de Gennes approach, we investigate the Majorana bound state (MBS) in a vortex of proximity-induced superconductivity on the surface of a topological insulator. Mapping out the local density of states (LDOS) of quasiparticle excitations as a function of energy and distance from the vortex center, it is found that the spectral distribution evolves from a V shape to a Y shape with the emergence of a MBS upon variation of the chemical potential, consistent with the STM/STS measurement in a very recent experiment [Xu et al., Phys. Rev. Lett. 114, 017001 (2015)] on a Bi2Te3 thin layer on the top of NbSe2 . Moreover, we demonstrate that there is a checkerboard-type pattern in the relative LDOS between the spin-up and -down channels, where the quantum mechanical wave function of the MBS manifests itself clearly as a single quantum state. Therefore, a spin-resolved STM/STS technique is expected to be able to provide phase-sensitive evidence for a MBS in the vortex core of a topological superconductor.

  11. Observation of dual-wavelength solitons and bound states in a nanotube/microfiber mode-locking fiber laser

    NASA Astrophysics Data System (ADS)

    Zeng, C.; Cui, Y. D.; Guo, J.

    2015-07-01

    We report on the experimental observation of dual-wavelength soliton and the phase-locked bound state in an all-fiber laser mode-locked by a carbon nanotubes/microfiber saturable absorber. The operation wavelengths are strongly dependent on the intracavity loss. By adjusting an attenuator to increase the intracavity loss, mode-locking wavelength shifts from 1557 to 1531 nm. With the appropriate pump power and intracavity loss, dual-wavelength solitons are achieved simultaneously. In addition, the phase-locked bound-state solitons are also observed at the two wavelengths. The pulse separation and phase difference are related to the first-order Kelly sidebands.

  12. Quantum phase transition triggering magnetic bound states in the continuum in graphene

    NASA Astrophysics Data System (ADS)

    Guessi, L. H.; Marques, Y.; Machado, R. S.; Kristinsson, K.; Ricco, L. S.; Shelykh, I. A.; Figueira, M. S.; de Souza, M.; Seridonio, A. C.

    2015-12-01

    Graphene hosting a pair of collinear adatoms in the phantom atom configuration has density of states vanishing in the vicinity of the Dirac point which can be described in terms of the pseudogap scaling as cube of the energy, Δ ∝|ɛ| 3 , which leads to the appearance of spin-degenerate bound states in the continuum (BICs) [Phys. Rev. B 92, 045409 (2015), 10.1103/PhysRevB.92.045409]. In the case when adatoms are locally coupled to a single carbon atom the pseudogap scales linearly with energy, which prevents the formation of BICs. Here, we explore the effects of nonlocal coupling characterized by the Fano factor of interference q0, tunable by changing the slope of the Dirac cones in the graphene band structure. We demonstrate that three distinct regimes can be identified: (i) for q0qc 2 the cubic scaling of the pseudogap with energy Δ ∝|ɛ| 3 characteristic to the phantom atom configuration is restored and the phase with nonmagnetic BICs is recovered. The phase with magnetic BICs can be described in terms of an effective intrinsic exchange field of ferromagnetic nature between the adatoms mediated by graphene monolayer. We thus propose a new type of QPT resulting from the competition between two ground states, respectively characterized by spin-degenerate and magnetic BICs.

  13. Boosting QED and QCD bound states in the path integral formalism

    NASA Astrophysics Data System (ADS)

    Simonov, Yu. A.

    2015-03-01

    Wave functions and energy eigenvalues of the path integral Hamiltonian are studied in the Lorentz frame moving with velocity v . The instantaneous interaction produced by the Wilson loop is shown to be reduced by an overall factor √{1 -(v/c )2 }. As a result, one obtains the boosted energy eigenvalues in the Lorentz covariant form E =√{P2+M02 } , where M0 is the c.m. energy, and this form is tested for two free particles and for the Coulomb and linear interaction. Using Lorentz-contracted wave functions of the bound states, one obtains the scaled-parton wave functions and valence quark distributions for large P . Matrix elements containing wave functions moving with different velocities strongly decrease with growing relative momentum; e.g., for the timelike form factors, one obtains Fh(Q0)˜(M/hQ_0)2 nh with nh=1 and 2 for mesons and baryons, as in the "quark counting rule."

  14. Shot noise as a measure of the lifetime and energy splitting of Majorana bound states

    SciTech Connect

    Lü, Hai-Feng; Guo, Zhen; Ke, Sha-Sha; Zhang, Huai-Wu; Guo, Yong

    2015-04-28

    We propose a scheme to measure the lifetime and energy splitting of a pair of Majorana bound states at the ends of a superconducting nanowire by using the shot noise in a dynamical channel blockade system. A quantum dot is coupled to one end of the wire and connected with two electron reservoirs. It is found that a finite Majorana energy splitting tends to produce a super-Poissonian shot noise, while Majorana relaxation process relieves the dynamical channel blockade and suppresses the noise Fano factor. When the dot energy level locates in the middle of the gap of topological superconductor, the Fano factor is independent on Majorana lifetime and Majorana energy splitting is thus extracted. For a finite energy splitting, we could evaluate the Majorana relaxation rate from the suppression of Fano factor. Under a realistic condition, the expected resolution of Majorana energy splitting and its relaxation rate calculated from our model are about 1μeV and 0.01−1μeV, respectively.

  15. Space-bound optical source for satellite-ground decoy-state quantum key distribution.

    PubMed

    Li, Yang; Liao, Sheng-Kai; Chen, Xie-Le; Chen, Wei; Cheng, Kun; Cao, Yuan; Yong, Hai-Lin; Wang, Tao; Yang, Hua-Qiang; Liu, Wei-Yue; Yin, Juan; Liang, Hao; Peng, Cheng-Zhi; Pan, Jian-Wei

    2014-11-01

    Satellite-ground quantum key distribution has embarked on the stage of engineering implementation, and a global quantum-secured network is imminent in the foreseeable future. As one payload of the quantum-science satellite which will be ready before the end of 2015, we report our recent work of the space-bound decoy-state optical source. Specialized 850 nm laser diodes have been manufactured and the integrated optical source has gotten accomplished based on these LDs. The weak coherent pulses produced by our optical source feature a high clock rate of 100 MHz, intensity stability of 99.5%, high polarization fidelity of 99.7% and phase randomization. A series of space environment tests have been conducted to verify the optical source's performance and the results are satisfactory. The emulated final secure keys are about 120 kbits during one usable pass of the low Earth orbit satellite. This work takes a significant step forward towards satellite-ground QKD and the global quantum-secured network. PMID:25401878

  16. Shot noise as a measure of the lifetime and energy splitting of Majorana bound states

    NASA Astrophysics Data System (ADS)

    Lü, Hai-Feng; Guo, Zhen; Ke, Sha-Sha; Guo, Yong; Zhang, Huai-Wu

    2015-04-01

    We propose a scheme to measure the lifetime and energy splitting of a pair of Majorana bound states at the ends of a superconducting nanowire by using the shot noise in a dynamical channel blockade system. A quantum dot is coupled to one end of the wire and connected with two electron reservoirs. It is found that a finite Majorana energy splitting tends to produce a super-Poissonian shot noise, while Majorana relaxation process relieves the dynamical channel blockade and suppresses the noise Fano factor. When the dot energy level locates in the middle of the gap of topological superconductor, the Fano factor is independent on Majorana lifetime and Majorana energy splitting is thus extracted. For a finite energy splitting, we could evaluate the Majorana relaxation rate from the suppression of Fano factor. Under a realistic condition, the expected resolution of Majorana energy splitting and its relaxation rate calculated from our model are about 1 μ eV and 0.01 - 1 μ eV , respectively.

  17. Tunable transport through a quantum dot chain with side-coupled Majorana bound states

    SciTech Connect

    Jiang, Cui; Lu, Gang; Gong, Wei-Jiang

    2014-09-14

    We investigate the transport properties of a quantum dot (QD) chain side-coupled to a pair of Majorana bound states (MBSs). It is found that the zero-bias conductance is tightly dependent on the parity of QD number. First, if a Majorana zero mode is introduced to couple to one QD of the odd-numbered QD structure, the zero-bias conductance is equal to (e{sup 2})/(2h) , but the zero-bias conductance will experience a valley-to-peak transition if the Majorana zero mode couples to the different QDs of the even-numbered QD structure. On the other hand, when the inter-MBS coupling is nonzero, the zero-bias conductance spectrum shows a peak in the odd-numbered QD structure, and in the even-numbered QD structure one conductance valley appears at the zero-bias limit. These results show the feasibility to manipulate the current in a multi-QD structure based on the QD-MBS coupling. Also, such a system can be a candidate for detecting the MBSs.

  18. Surface-Bound Ruthenium Diimine Organometallic Complexes: Excited-State Properties

    PubMed Central

    2015-01-01

    Ruthenium complexes of the general formula [Ru(CO)(H)(L2)(L′2)][PF6] (L2 = trans-2PPh3, L′ = η2-4,4′-dicarboxybipyridine (1); L2 =trans-2Ph2PCH2CH2COOH, L′2 = bipyridine (2); L2 = Ph2PCHCHPPh2, L′ = η2-5-amino-1,10-phenanthroline (3); L2 = trans-2PPh3, L′2 = η2-4-carboxaldehyde-4′-methylbipyridine (4)) have been shown to have longer emission lifetimes and higher quantum yields in solution compared with more symmetrical molecules such as [Ru(bpy)3][Cl]2. Compound 4 is obtained as a mixture with the corresponding acetal, 4′. These less symmetrical complexes have been covalently immobilized on the surface of silica polyamine composites, and their photophysical properties have been studied. The surface-bound complexes have been characterized by solid-state CPMAS 13C, 31P, and 29Si NMR, UV–vis, and FT-IR spectroscopies. Excited-state lifetime studies revealed that, in general, the lifetimes of the immobilized complexes are 1.4 to 8 times longer than in solution and are dependent on particle size (300–500 μm versus 10–20 nm average diameter silica gels), polymer structure (linear poly(allylamine) versus branched poly(ethylenimine)), and the type of surface tether. One exception to this trend is the previously reported complex [Ru(bpy)2(5-amino-1,10-phenanthroline)][PF6]2 (5), where only a slight increase in lifetime is observed. Only minor changes in emission wavelength are observed for all the complexes. This opens up the possibility for enhanced heterogeneous electron transfer in photocatalytic reactions. PMID:24891753

  19. Membrane-bound states of alpha-lactalbumin: implications for the protein stability and conformation.

    PubMed Central

    Cawthern, K. M.; Permyakov, E.; Berliner, L. J.

    1996-01-01

    alpha-Lactalbumin (alpha-LA) associates with dimyristoylphosphatidylcholine (DMPC) or egg lecithin (EPC) liposomes. Thermal denaturation of isolated DMPC or EPC alpha-LA complexes was dependent on the metal bound state of the protein. The intrinsic fluorescence of thermally denatured DMPC-alpha-LA was sensitive to two thermal transitions: the Tc of the lipid vesicles, and the denaturation of the protein. Quenching experiments suggested that tryptophan accessibility increased upon protein-DMPC association, in contrast with earlier suggestions that the limited emission red shift upon association with the liposome was due to partial insertion of tryptophan into the apolar phase of the bilayer (Hanssens I et al., 1985, Biochim Biophys Acta 817:154-166). On the other hand, above the protein transition (70 degrees C), the spectral blue shifts and reduced accessibility to quencher suggested that tryptophan interacts significantly with the apolar phase of either DMPC and EPC. At pH 2, where the protein inserts into the bilayer rapidly, the isolated DMPC-alpha-LA complex showed a distinct fluorescence thermal transition between 40 and 60 degrees C, consistent with a partially inserted form that possesses some degree of tertiary structure and unfolds cooperatively. This result is significant in light of earlier findings of increased helicity for the acid form, i.e., molten globule state of the protein (Hanssens I et al., 1985, Biochim Biophys Acta 817:154-166). These results suggest a model where a limited expansion of conformation occurs upon association with the membrane at neutral pH and physiological temperatures, with a concomitant increase in the exposure of tryptophan to external quenchers; i.e., the current data do not support a model where an apolar, tryptophan-containing surface is covered by the lipid phase of the bilayer. PMID:8819172

  20. A spherically symmetric bound state of the coupled Maxwell-Dirac equations with self-interaction alone

    NASA Astrophysics Data System (ADS)

    Bradford, R. A. W.

    2015-10-01

    Stationary, static, spherically symmetric solutions of the Maxwell-Dirac system, treated as classical fields, have been found which are localised and normalisable. The solutions apply to any bound energy eigenvalue in the range 0 < E < m, where m is the bare mass in the Dirac equation. A point charge of any magnitude and either sign may be placed at the origin and the solutions remain well behaved and bound. However, no such central charge is necessary to result in a bound solution. As found previously by Radford, the magnetic flux density is equal to that of a monopole at the origin. However, no monopole is present, the magnetic flux being a result of the dipole moment distribution of the Dirac field. The Dirac field magnetic dipole moment is aligned with the magnetic flux density and so the resulting magnetic self-energy is negative. It is this which results in the states being bound (E < m). The case which omits any central point charge is therefore a self-sustaining bound state solution of the Maxwell-Dirac system which is localised, normalisable, and requires no arbitrarily added "external" features (i.e., it is a soliton). As far as the author is aware, this is the first time that such an exact solution with a positive energy eigenvalue has been reported. However, the solution is not unique since the energy eigenvalue is arbitrary within the range 0 < E < m. The stability of the solution has not been addressed.

  1. Hierarchy of bound states in the one-dimensional ferromagnetic Ising chain CoNb2O6 investigated by high-resolution time-domain terahertz spectroscopy.

    PubMed

    Morris, C M; Valdés Aguilar, R; Ghosh, A; Koohpayeh, S M; Krizan, J; Cava, R J; Tchernyshyov, O; McQueen, T M; Armitage, N P

    2014-04-01

    Kink bound states in the one-dimensional ferromagnetic Ising chain compound CoNb2O6 have been studied using high-resolution time-domain terahertz spectroscopy in zero applied magnetic field. When magnetic order develops at low temperature, nine bound states of kinks become visible. Their energies can be modeled exceedingly well by the Airy function solutions to a 1D Schrödinger equation with a linear confining potential. This sequence of bound states terminates at a threshold energy near 2 times the energy of the lowest bound state. Above this energy scale we observe a broad feature consistent with the onset of the two particle continuum. At energies just below this threshold we observe a prominent excitation that we interpret as a novel bound state of bound states--two pairs of kinks on neighboring chains. PMID:24745454

  2. Theoretical study of photoproduction of an η'N bound state on a deuteron target with forward proton emission

    NASA Astrophysics Data System (ADS)

    Sekihara, Takayasu; Sakai, Shuntaro; Jido, Daisuke

    2016-08-01

    Possibilities of observing a signal of an η'n bound state are investigated by considering photoproductions of the η and η' mesons on a deuteron target with forward proton emission. For this purpose, we take the η'n interaction from the linear σ model with a coupling to η n , in which an s -wave η'n bound state can be dynamically generated, and we fix the γ p →η p and η'p scattering amplitudes so as to reproduce the experimental cross sections with forward proton emission. By using these γ p →η(')p and η(')n →η(')n amplitudes, we calculate cross sections of the γ d →η n p and η'n p reactions with forward proton emission in single and η(')-exchange double-scattering processes. As a result, we find that the signal of the η'n bound state can be seen below the η'n threshold in the η n invariant mass spectrum of the γ d →η n p reaction and is comparable with the contribution from the quasifree η' production above the η'n threshold. We also discuss the behavior of the signal of the η'n bound state in several experimental conditions and model parameters.

  3. On the spin- 1/2 Aharonov–Bohm problem in conical space: Bound states, scattering and helicity nonconservation

    SciTech Connect

    Andrade, F.M.; Silva, E.O.; Pereira, M.

    2013-12-15

    In this work the bound state and scattering problems for a spin- 1/2 particle undergone to an Aharonov–Bohm potential in a conical space in the nonrelativistic limit are considered. The presence of a δ-function singularity, which comes from the Zeeman spin interaction with the magnetic flux tube, is addressed by the self-adjoint extension method. One of the advantages of the present approach is the determination of the self-adjoint extension parameter in terms of physics of the problem. Expressions for the energy bound states, phase-shift and S matrix are determined in terms of the self-adjoint extension parameter, which is explicitly determined in terms of the parameters of the problem. The relation between the bound state and zero modes and the failure of helicity conservation in the scattering problem and its relation with the gyromagnetic ratio g are discussed. Also, as an application, we consider the spin- 1/2 Aharonov–Bohm problem in conical space plus a two-dimensional isotropic harmonic oscillator. -- Highlights: •Planar dynamics of a spin- 1/2 neutral particle. •Bound state for Aharonov–Bohm systems. •Aharonov–Bohm scattering. •Helicity nonconservation. •Determination of the self-adjoint extension parameter.

  4. Bound states of two spin-(1/2) fermions in a synthetic non-Abelian gauge field

    SciTech Connect

    Vyasanakere, Jayantha P.; Shenoy, Vijay B.

    2011-03-01

    We study the bound states of two spin-(1/2) fermions interacting via a contact attraction (characterized by a scattering length) in the singlet channel in three-dimensional space in presence of a uniform non-Abelian gauge field. The configuration of the gauge field that generates a Rashba-type spin-orbit interaction is described by three coupling parameters ({lambda}{sub x},{lambda}{sub y},{lambda}{sub z}). For a generic gauge field configuration, the critical scattering length required for the formation of a bound state is negative, i.e., shifts to the ''BCS side'' of the resonance. Interestingly, we find that there are special high-symmetry configurations (e.g., {lambda}{sub x}={lambda}{sub y}={lambda}{sub z}) for which there is a two-body bound state for anyscattering length however small and negative. Remarkably, the bound-state wave functions obtained for such configurations have nematic spin structure similar to those found in liquid {sup 3}He. Our results show that the BCS-BEC (Bose-Einstein condensation) crossover is drastically affected by the presence of a non-Abelian gauge field. We discuss possible experimental signatures of our findings both at high and low temperatures.

  5. Reprint of : Effect of a tunnel barrier on the scattering from a Majorana bound state in an Andreev billiard

    NASA Astrophysics Data System (ADS)

    Marciani, M.; Schomerus, H.; Beenakker, C. W. J.

    2016-08-01

    We calculate the joint distribution P(S , Q) of the scattering matrix S and time-delay matrix Q = - iℏS† dS / dE of a chaotic quantum dot coupled by point contacts to metal electrodes. While S and Q are statistically independent for ballistic coupling, they become correlated for tunnel coupling. We relate the ensemble averages of Q and S and thereby obtain the average density of states at the Fermi level. We apply this to a calculation of the effect of a tunnel barrier on the Majorana resonance in a topological superconductor. We find that the presence of a Majorana bound state is hidden in the density of states and in the thermal conductance if even a single scattering channel has unit tunnel probability. The electrical conductance remains sensitive to the appearance of a Majorana bound state, and we calculate the variation of the average conductance through a topological phase transition.

  6. Analytical study of bound states in graphene nanoribbons and carbon nanotubes: The variable phase method and the relativistic Levinson theorem

    NASA Astrophysics Data System (ADS)

    Miserev, D. S.

    2016-06-01

    The problem of localized states in 1D systems with a relativistic spectrum, namely, graphene stripes and carbon nanotubes, is studied analytically. The bound state as a superposition of two chiral states is completely described by their relative phase, which is the foundation of the variable phase method (VPM) developed herein. Based on our VPM, we formulate and prove the relativistic Levinson theorem. The problem of bound states can be reduced to the analysis of closed trajectories of some vector field. Remarkably, the Levinson theorem appears as the Poincaré index theorem for these closed trajectories. The VPM equation is also reduced to the nonrelativistic and semiclassical limits. The limit of a small momentum p y of transverse quantization is applicable to an arbitrary integrable potential. In this case, a single confined mode is predicted.

  7. Effect of a tunnel barrier on the scattering from a Majorana bound state in an Andreev billiard

    NASA Astrophysics Data System (ADS)

    Marciani, M.; Schomerus, H.; Beenakker, C. W. J.

    2016-03-01

    We calculate the joint distribution P(S, Q) of the scattering matrix S and time-delay matrix Q = - iℏ S† dS / dE of a chaotic quantum dot coupled by point contacts to metal electrodes. While S and Q are statistically independent for ballistic coupling, they become correlated for tunnel coupling. We relate the ensemble averages of Q and S and thereby obtain the average density of states at the Fermi level. We apply this to a calculation of the effect of a tunnel barrier on the Majorana resonance in a topological superconductor. We find that the presence of a Majorana bound state is hidden in the density of states and in the thermal conductance if even a single scattering channel has unit tunnel probability. The electrical conductance remains sensitive to the appearance of a Majorana bound state, and we calculate the variation of the average conductance through a topological phase transition.

  8. Approximate bound-state solutions of the Dirac equation for the generalized yukawa potential plus the generalized tensor interaction

    NASA Astrophysics Data System (ADS)

    Ikot, Akpan N.; Maghsoodi, Elham; Hassanabadi, Hassan; Obu, Joseph A.

    2014-05-01

    In this paper, we obtain the approximate analytical bound-state solutions of the Dirac particle with the generalized Yukawa potential within the framework of spin and pseudospin symmetries for the arbitrary к state with a generalized tensor interaction. The generalized parametric Nikiforov-Uvarov method is used to obtain the energy eigenvalues and the corresponding wave functions in closed form. We also report some numerical results and present figures to show the effect of the tensor interaction.

  9. Oscillations at the transition between the bounded state and the spout state of the selective withdrawal from a capillary geometry

    NASA Astrophysics Data System (ADS)

    Wyman, Jason L.

    Selective withdrawal occurs when a thin spout of fluid A is viscously entrained by a convergent flow of a second, immiscible fluid B. The associated selective withdrawal transition is the process by which the interface between the two fluids undergoes a topological transition from a bounded surface with no entrainment to an unbounded surface with a spout of fluid A piercing the bulk of fluid B. This transition which occurs due to changes in the imposed flow of fluid B, is well studied for the case of a planar interface between the two fluids. This paper examines the transition when the interface consists of a curved droplet of water (fluid A) protruding from a capillary within a volume of oil (fluid B). A qualitatively new, non-stationary state is observed in which the interface oscillates and intermittently ejects small volumes of water. As a control parameter is varied, both the timescale of this ejection, Tspit, and the amplitude of oscillation, A, decrease by several orders of magnitude consistent with a power law: Tspit ∝ A3/2. Within this scaling, mode locking onto various externally influenced frequencies and complex multiperiodic oscillations are observed.

  10. Hierarchy of Bound States in the One-Dimensional Ferromagnetic Ising Chain CoNb2O6 Investigated by High-Resolution Time-Domain Terahertz Spectroscopy

    NASA Astrophysics Data System (ADS)

    Morris, C. M.; Valdés Aguilar, R.; Ghosh, A.; Koohpayeh, S. M.; Krizan, J.; Cava, R. J.; Tchernyshyov, O.; McQueen, T. M.; Armitage, N. P.

    2014-04-01

    Kink bound states in the one-dimensional ferromagnetic Ising chain compound CoNb2O6 have been studied using high-resolution time-domain terahertz spectroscopy in zero applied magnetic field. When magnetic order develops at low temperature, nine bound states of kinks become visible. Their energies can be modeled exceedingly well by the Airy function solutions to a 1D Schrödinger equation with a linear confining potential. This sequence of bound states terminates at a threshold energy near 2 times the energy of the lowest bound state. Above this energy scale we observe a broad feature consistent with the onset of the two particle continuum. At energies just below this threshold we observe a prominent excitation that we interpret as a novel bound state of bound states—two pairs of kinks on neighboring chains.

  11. Tunneling spectroscopy of a single quantum dot coupled to a superconductor: From Kondo ridge to Andreev bound states

    NASA Astrophysics Data System (ADS)

    Pillet, J.-D.; Joyez, P.; Žitko, Rok; Goffman, M. F.

    2013-07-01

    We performed tunneling spectroscopy of a carbon nanotube quantum dot (QD) coupled to a metallic reservoir either in the normal or in the superconducting state. We explore how the Kondo resonance, observed when the QD's occupancy is odd and the reservoir is normal, evolves towards Andreev bound states (ABS) in the superconducting state. Within this regime, the ABS spectrum observed is consistent with a quantum phase transition from a singlet to a degenerate magnetic doublet ground state, in quantitative agreement with a single-level Anderson model with superconducting leads.

  12. Coulomb Driven New Bound States at the Integer Quantum Hall States in GaAs/Al(0.3)Ga(0.7)As Single Heterojunctions

    SciTech Connect

    Jiang, H.W.; Kim, Yongmin; Lee, Kyu-Seok; Lee, X.; Munteanu, F.M.; Perry, C.H.; Simmons, J.A.

    1999-05-25

    Coulomb driven, magneto-optically induced electron and hole bound states from a series of heavily doped GaAs/Al0.3Ga0.7As single heterojunctions (SHJ) are revealed in high magnetic fields. At low magnetic fields ({nu} >2), the photohuninescence spectra display Shubnikov de-Haas type oscillations associated with the empty second subband transition. In the regime of the Landau filling factor {nu} <1 and 1< {nu} <2, we found strong bound states due to Mott type Vocalizations. Since a SHJ has an open valence band structure, these bound states area unique property of the dynamic movement of the valence holes in strong magnetic fields.

  13. Feshbach resonances and weakly bound molecular states of boson-boson and boson-fermion NaK pairs

    NASA Astrophysics Data System (ADS)

    Viel, Alexandra; Simoni, Andrea

    2016-04-01

    We conduct a theoretical study of magnetically induced Feshbach resonances and near-threshold bound states in isotopic NaK pairs. Our calculations accurately reproduce Feshbach spectroscopy data on Na 40K and explain the origin of the observed multiplets in the p wave [Phys. Rev. A 85, 051602(R) (2012), 10.1103/PhysRevA.85.051602]. We apply the model to predict scattering and bound state threshold properties of the boson-boson Na 39K and Na 41K systems. We find that the Na 39K isotopic pair presents broad magnetic Feshbach resonances and favorable ground-state features for producing nonreactive polar molecules by two-photon association. Broad s -wave resonances are also predicted for Na 41K collisions.

  14. Application of solid state NMR for the study of surface bound species and fossil fuels

    NASA Astrophysics Data System (ADS)

    Althaus, Stacey

    Recent advances in solid state NMR have been utilized to study a variety of systems. These advancements have allowed for the acquisition of sequences previously only available for solution state detection. The protocol for the measurement of coals and other carbonaceous materials was updated to incorporate the recent advancements in fast magic angle spinning (MAS) and high magnetic fields. Argonne Premium Coals were used to test the sensitivity and resolution of the experiments preformed at high field and fast MAS. The higher field spectra were shown to be slightly less sensitive than the traditional lower field spectra, however, the new high field fast MAS spectra had better resolution. This increased resolution allowed for the separation of a variety of different functional groups, thereby allowing the composition of the coal to be determined. The use of 1 H detection allowed for 2D spectra of coals for the first time. These spectra could be filtered to examine either through-space or through-bond correlations. Indirect detection via 1 H was also pivotal in the detection of natural abundance 15 N spectra. Through-space and through-bond 2D spectra of natural abundance bulk species are shown with a sensitivity increase of 15 fold over traditional detection. This sensitivity enhancement allowed for the detection of natural abundance 15 N surface bound species in 2D, something that could not be acquired via traditional methods. The increased efficiency of the through-space magnetization transfer, Cross polarization, at fast MAS compared to the slower MAS rates is shown. The through-bond magnetization transfer via INEPT was examined and the effect of J-coupling is confirmed. Solid State NMR can be utilized to help improve catalytic interactions. Solid state NMR was used to examine the aldol condensation between p-nitrobenzaldehyde and acetone. The formation of a stable intermediate with p-nitrobenzaldehyde was found on the primary functionalized amine mesoporous

  15. Single-molecule imaging reveals a collapsed conformational state for DNA-bound cohesin

    PubMed Central

    Stigler, Johannes; Çamdere, Gamze Ö.; Koshland, Douglas E.; Greene, Eric C.

    2016-01-01

    Cohesin is essential for the hierarchical organization of the eukaryotic genome and plays key roles in many aspects of chromosome biology. The conformation of cohesin bound to DNA remains poorly defined, leaving crucial gaps in our understanding of how cohesin fulfills its biological functions. Here we use single molecule microscopy to directly observe the dynamic and functional characteristics of cohesin bound to DNA. We show that cohesin can undergo rapid one-dimensional (1D) diffusion along DNA, but individual nucleosomes, nucleosome arrays, and other protein obstacles significantly restrict its mobility. We further demonstrate that DNA motor proteins can readily push cohesin along DNA, but they cannot pass through the interior of the cohesin ring. Together, our results reveal that DNA-bound cohesin has a central pore that is substantially smaller than anticipated. These findings have direct implications for understanding how cohesin and other SMC proteins interact with and distribute along chromatin. PMID:27117417

  16. Vibrational Spectroscopy of Transient Dipolar Radicals via Autodetachment of Dipole-Bound States of Cold Anions

    NASA Astrophysics Data System (ADS)

    Huang, Dao-Ling; Liu, Hong-Tao; Dau, Phuong Diem; Wang, Lai-Sheng

    2014-06-01

    High-resolution vibrational spectroscopy of transient species is important for determining their molecular structures and understanding their chemical reactivity. However, the low abundance and high reactivity of molecular radicals pose major challenges to conventional absorption spectroscopic methods. The observation of dipole-bound states (DBS) in anions extend autodetachment spectroscopy to molecular anions whose corresponding neutral radicals possess a large enough dipole moment (>2.5 D).1,2 However, due to the difficulty of assigning the congested spectra at room temperature, there have been only a limited number of autodetachment spectra via DBS reported. Recently, we have built an improved version of a cold trap3 coupled with high-resolution photoelectron imaging.4 The first observation of mode-specific auotodetachment of DBS of cold phenoxide have shown that not only vibrational hot bands were completely suppressed, but also rotational profile was observed.5 The vibrational frequencies of the DBS were found to be the same as those of the neutral radical, suggesting that vibrational structures of dipolar radicals can be probed via DBS.5 More significantly, the DBS resonances allowed a number of vibrational modes with very weak Frank-Condon factors to be "lightened" up via vibrational autodetachment.5 Recently, our first high-resolution vibrational spectroscopy of the dehydrogenated uracil radical, with partial rotational resolution, via autodetachment from DBS of cold deprotonated uracil anions have been reported.6 Rich vibrational information is obtained for this important radical species. The resolved rotational profiles also allow us to characterize the rotational temperature of the trapped anions for the first time.6 1 K. R. Lykke, D. M. Neumark, T. Andersen, V. J. Trapa, and W. C. Lineberger, J. Chem. Phys. 87, 6842 (1987). 2 D. M. Wetzel, and J. I. Brauman, J. Chem. Phys. 90, 68 (1989). 3 P. D. Dau, H. T. Liu, D. L. Huang, and L. S. Wang, J. Chem. Phys

  17. Upper bounds for the security of differential-phase-shift quantum key distribution with weak coherent states

    NASA Astrophysics Data System (ADS)

    Curty, Marcos; Tamaki, Kiyoshi; Moroder, Tobias; Gómez-Sousa, Hipólito

    2009-04-01

    In this paper we present limitations imposed by sequential attacks on the maximal distance achievable by a differential-phase-shift (DPS) quantum key distribution (QKD) protocol with weak coherent pulses. Specifically, we compare the performance of two possible sequential attacks against DPS QKD where Eve realizes, respectively, optimal unambiguous state discrimination of Alice's signal states, and optimal unambiguous discrimination of the relative phases between consecutive signal states. We show that the second eavesdropping strategy provides tighter upper bounds for the security of a DPS QKD scheme than the former one.

  18. Lower bound for the variation of the hyperfine populations in the ground state of spin-1 condensates against a magnetic field

    NASA Astrophysics Data System (ADS)

    Xie, W. F.; He, Y. Z.; Bao, C. G.

    2015-10-01

    A simple and analytical expression for the variation of the lower bound and upper bound of the population density ρ0 of hyperfine component μ = 0 particles in the ground state of spin-1 condensates against a magnetic field B has been derived. The lower bound has a distinguished feature, namely, it will tend to the actual ρ0 when B tends to zero and infinite. This feature assures that, in the whole range of B, the lower bound can provide an effective constraint. Numerical examples are given to demonstrate the applicability of the bound.

  19. Single-Molecule Folding Mechanisms of the apo- and Mg2+-Bound States of Human Neuronal Calcium Sensor-1

    PubMed Central

    Naqvi, Mohsin M.; Heidarsson, Pétur O.; Otazo, Mariela R.; Mossa, Alessandro; Kragelund, Birthe B.; Cecconi, Ciro

    2015-01-01

    Neuronal calcium sensor-1 (NCS-1) is the primordial member of a family of proteins responsible primarily for sensing changes in neuronal Ca2+ concentration. NCS-1 is a multispecific protein interacting with a number of binding partners in both calcium-dependent and independent manners, and acting in a variety of cellular processes in which it has been linked to a number of disorders such as schizophrenia and autism. Despite extensive studies on the Ca2+-activated state of NCS proteins, little is known about the conformational dynamics of the Mg2+-bound and apo states, both of which are populated, at least transiently, at resting Ca2+ conditions. Here, we used optical tweezers to study the folding behavior of individual NCS-1 molecules in the presence of Mg2+ and in the absence of divalent ions. Under tension, the Mg2+-bound state of NCS-1 unfolds and refolds in a three-state process by populating one intermediate state consisting of a folded C-domain and an unfolded N-domain. The interconversion at equilibrium between the different molecular states populated by NCS-1 was monitored in real time through constant-force measurements and the energy landscapes underlying the observed transitions were reconstructed through hidden Markov model analysis. Unlike what has been observed with the Ca2+-bound state, the presence of Mg2+ allows both the N- and C-domain to fold through all-or-none transitions with similar refolding rates. In the absence of divalent ions, NCS-1 unfolds and refolds reversibly in a two-state reaction involving only the C-domain, whereas the N-domain has no detectable transitions. Overall, the results allowed us to trace the progression of NCS-1 folding along its energy landscapes and provided a solid platform for understanding the conformational dynamics of similar EF-hand proteins. PMID:26153708

  20. Metallocorrole Interactions with Carbon Monoxide, Nitric Oxide, and Nitroxyl-A DFT Study of Low-Energy Bound States.

    PubMed

    Vazquez-Lima, Hugo; Conradie, Jeanet; Ghosh, Abhik

    2016-09-01

    Presented herein is a first DFT survey of metallocorrole (M = Mn, Fe, Co) adducts of CO, NO, NO(-), and HNO. Bound states with relatively short M-N(O) distances <1.9 Å are predicted for both [M(Cor)(NO)](-) and [M(Cor)(HNO)] derivatives for all three metals. The calculations also confirm the existence of moderately stable charge-neutral CoCO corrole adducts. PMID:27525455

  1. ( p, q)-five brane and ( p, q)-string solutions, their bound state and its near horizon limit

    NASA Astrophysics Data System (ADS)

    Klusoň, Josef

    2016-06-01

    We determine ( p, q)-string and ( p, q)-five brane solutions of type IIB supergravity using SL (2 , ℤ)-symmetry of the full type IIB superstring theory. We also determine SL (2 , ℤ)-transformed solution corresponding to the bound state of NS5-branes and fundamental strings. Then we analyze its near horizon limit and we show that it leads to the AdS3 × S 3 with mixed fluxes.

  2. Bound state solution of Dirac equation for Hulthen plus trigonometric Rosen Morse non-central potential using Romanovski polynomial

    SciTech Connect

    Suparmi, A. Cari, C.; Angraini, L. M.

    2014-09-30

    The bound state solutions of Dirac equation for Hulthen and trigonometric Rosen Morse non-central potential are obtained using finite Romanovski polynomials. The approximate relativistic energy spectrum and the radial wave functions which are given in terms of Romanovski polynomials are obtained from solution of radial Dirac equation. The angular wave functions and the orbital quantum number are found from angular Dirac equation solution. In non-relativistic limit, the relativistic energy spectrum reduces into non-relativistic energy.

  3. Search for pion-neutron bound states in 14.6{ital A} GeV Si + nucleus collisions

    SciTech Connect

    Barrette, J.; Bellwied, R.; Braun-Munzinger, P.; Cleland, W.E.; Cormier, T.; Dadusc, G.; David, G.; Dee, J.; Dietzsch, O.; Fatyga, M.; Greene, S.V.; Germani, J.V.; Hall, J.R.; Hemmick, T.K.; Herrmann, N.; Hogue, R.W.; Hong, B.; Jayananda, K.; Kraus, D.; Kumar, B.S.; Lacasse, R.; Lissauer, D.; Llope, W.J.; Ludlam, T.W.; Majka, R.; Mark, S.K.; Mitchell, J.T.; Muthuswamy, M.; O`Brien, E.; Pruneau, C.; Rotondo, F.S.; da Silva, N.C.; Simon-Gillo, J.; Sonnadara, U.; Stachel, J.; Takai, H.; Takagui, E.M.; Throwe, T.G.; Waters, L.; Winter, C.; Wolfe, D.; Woody, C.L.; Xu, N.; Zhang, Y.; Zhang, Z.; Zou, C. ||||||||

    1995-11-01

    We have conducted a search for bound states of a negative pion and a number of neutrons (pineuts) using the E814 spectrometer. A beam of {sup 28}Si at a momentum of 14.6{ital A} GeV/{ital c} was used to bombard targets of Al, Cu, Sn, and Pb. We describe our experimental technique, present measured upper limits for pineut production, and discuss the significance of our results.

  4. Photoproduction of Structure in the dπ System Near the NΔ mass: Sign of a Quasi-Bound State?

    NASA Astrophysics Data System (ADS)

    Schumacher, Reinhard

    2015-04-01

    Results from nucleon-nucleon and pion-deuteron scattering analysis show attractive resonance-like behavior in certain partial waves. But evidence for clear-cut baryon-baryon (quasi-) bound states other than the deuteron remains lacking, despite theoretical expectations that they can exist. In recent years some measurements using pd scattering have interpreted a broad bump in the dππ invariant mass distribution in terms of a ΔΔ dibaryonic resonance. If such a quasi-bound state exists, then one supposes that an NΔ quasi-bound state exists also, as supported by recent Fadeev-model calculations of the πNN system. Here we discuss ongoing work looking at the γd --> dπ+π- reaction using the CLAS detector at Jefferson Lab. A Dalitz-plot analysis shows structure in the invariant mass distributions in (dπ) + + and (dπ) 0 systems. Both are near the center of the NΔ mass distribution. Possible interpretations of this observation will be discussed. (for the CLAS Collaboration).

  5. Three-body bound states of two bosonic impurities immersed in a Fermi sea in 2D

    NASA Astrophysics Data System (ADS)

    Bellotti, F. F.; Frederico, T.; Yamashita, M. T.; Fedorov, D. V.; Jensen, A. S.; Zinner, N. T.

    2016-04-01

    We consider two identical impurities immersed in a Fermi sea for a broad range of masses and for both interacting and non-interacting impurities. The interaction between the particles is described through attractive zero-range potentials and the problem is solved in momentum space. The two impurities can attach to a fermion from the sea and form three-body bound states. The energy of these states increase as function of the Fermi momentum k F, leading to three-body bound states below the Fermi energy. The fate of the states depends highly on two- and three-body thresholds and we find evidence of medium-induced Borromean-like states in 2D. The corrections due to particle-hole fluctuations in the Fermi sea are considered in the three-body calculations and we show that in spite of the fact that they strongly affect both the two- and three-body systems, the correction to the point at which the three-body states cease to exist is small.

  6. Phonon dispersion and local density of states in NiPd alloy using modified embedded atom method potential

    NASA Astrophysics Data System (ADS)

    Joshi, Subodh; Chand, Manesh; Dabral, Krishna; Semalty, P. D.

    2016-05-01

    A modified embedded atom method (MEAM) potential model up to second neighbours has been used to calculate the phonon dispersions for Ni0.55Pd0.45 alloy in which Pd is introduced as substitutional impurity. Using the force-constants obtained from MEAM potential, the local vibrational density of states in host Ni and substitutional Pd atoms using Green's function method has been calculated. The calculation of phonon dispersions of NiPd alloy shows a good agreement with the experimental results. Condition of resonance mode has also been investigated and resonance mode in the frequency spectrum of impurity atom at low frequency is observed.

  7. Do the higher oxidation states of the photosynthetic O2-evolving system contain bound H2O?

    NASA Technical Reports Server (NTRS)

    Radmer, R.; Ollinger, O.

    1986-01-01

    A modified mass spectrometer was used to determine whether the higher oxidation states of the photosynthetic O2-evolving system contain substrate water that is not freely exchangeable with the external medium. Our data indicated that the higher oxidation states contain no appreciable bound, non-exchangeable H2O. This suggests that H2O oxidation takes place via a rapid, concerted, all-or-none mechanism rather than by a mechanism involving stable, partially oxidized, H2O-derived intermediates. These findings set definite constraints on possible mechanisms of O2 evolution.

  8. Electronic states in spherical GaN nanocrystals embedded in various dielectric matrices: The k ṡ p-calculations

    NASA Astrophysics Data System (ADS)

    Konakov, A. A.; Filatov, D. O.; Korolev, D. S.; Belov, A. I.; Mikhaylov, A. N.; Tetelbaum, D. I.; Kumar, Mahesh

    2016-01-01

    Using the envelope-function approximation, the single-particle states of electrons and holes in spherical GaN nanocrystals embedded in different amorphous dielectric matrices (SiO2, Al2O3, HfO2 and Si3N4) have been calculated. Ground state energies of electrons and holes in GaN nanocrystals are determined using the isotropic approximation of the k ṡ p -Hamiltonian. All the ground state energies are found to increase with lowering the nanocrystal size and are proportional to the R-n, where R is the nanocrystal radius, n =1.5-1.9 for electrons and 1.7-2.0 for holes. The optical gap of GaN nanocrystals changes from 3.8 to 5 eV for the nanocrystal radius ranging from 3 to 1 nm.

  9. Characterizing the Membrane-Bound State of Cytochrome P450 3A4: Structure, Depth of Insertion, and Orientation

    PubMed Central

    2013-01-01

    Cytochrome P450 3A4 (CYP3A4) is the most abundant membrane-associated isoform of the P450 family in humans and is responsible for biotransformation of more than 50% of drugs metabolized in the body. Despite the large number of crystallographic structures available for CYP3A4, no structural information for its membrane-bound state at an atomic level is available. In order to characterize binding, depth of insertion, membrane orientation, and lipid interactions of CYP3A4, we have employed a combined experimental and simulation approach in this study. Taking advantage of a novel membrane representation, highly mobile membrane mimetic (HMMM), with enhanced lipid mobility and dynamics, we have been able to capture spontaneous binding and insertion of the globular domain of the enzyme into the membrane in multiple independent, unbiased simulations. Despite different initial orientations and positions of the protein in solution, all the simulations converged into the same membrane-bound configuration with regard to both the depth of membrane insertion and the orientation of the enzyme on the surface of the membrane. In tandem, linear dichroism measurements performed on CYP3A4 bound to Nanodisc membranes were used to characterize the orientation of the enzyme in its membrane-bound form experimentally. The heme tilt angles measured experimentally are in close agreement with those calculated for the membrane-bound structures resulted from the simulations, thereby verifying the validity of the developed model. Membrane binding of the globular domain in CYP3A4, which appears to be independent of the presence of the transmembrane helix of the full-length enzyme, significantly reshapes the protein at the membrane interface, causing conformational changes relevant to access tunnels leading to the active site of the enzyme. PMID:23697766

  10. Two Active Site Divalent Ions in the Crystal Structure of the Hammerhead Ribozyme Bound to a Transition State Analogue.

    PubMed

    Mir, Aamir; Golden, Barbara L

    2016-02-01

    The crystal structure of the hammerhead ribozyme bound to the pentavalent transition state analogue vanadate reveals significant rearrangements relative to the previously determined structures. The active site contracts, bringing G10.1 closer to the cleavage site and repositioning a divalent metal ion such that it could, ultimately, interact directly with the scissile phosphate. This ion could also position a water molecule to serve as a general acid in the cleavage reaction. A second divalent ion is observed coordinated to O6 of G12. This metal ion is well-placed to help tune the pKA of G12. On the basis of this crystal structure as well as a wealth of biochemical studies, we propose a mechanism in which G12 serves as the general base and a magnesium-bound water serves as a general acid. PMID:26551631

  11. Scattering states of the Majorana-bound-state-supporting vortices at the interface of a topological insulator and an s-wave superconductor

    NASA Astrophysics Data System (ADS)

    Durst, Adam

    We consider an isolated vortex in the 2D proximity-induced superconducting state formed at the interface of a 3D topological insulator (TI) and an s-wave superconductor (sSC). Prior calculations of the bound states of this system famously revealed a zero-energy state that is its own conjugate, a Majorana fermion bound to the vortex core. We calculate, not the bound states, but the scattering states of this system, and ask how the spin-momentum-locked massless Dirac form of the single-particle Hamiltonian, inherited from the TI surface, affects the cross section for scattering Bogoliubov quasiparticles from the vortex. As in the case of an ordinary superconductor, this is a two-channel problem with the vortex mixing particle-like and hole-like excitations. And as in the ordinary case, the same-channel differential cross section diverges in the forward direction due to the Aharonov-Bohm effect, resulting in an infinite total cross section but finite transport and skew cross sections. We calculate the transport and skew cross sections numerically, via a partial wave analysis, as a function of both quasiparticle excitation energy and chemical potential. Novel effects emerge as particle-like or hole-like excitations are tuned through the Dirac point.

  12. Waveguide QED: Many-body bound-state effects in coherent and Fock-state scattering from a two-level system

    SciTech Connect

    Zheng Huaixiu; Baranger, Harold U.; Gauthier, Daniel J.

    2010-12-15

    Strong coupling between a two-level system (TLS) and bosonic modes produces dramatic quantum optics effects. We consider a one-dimensional continuum of bosons coupled to a single localized TLS, a system which may be realized in a variety of plasmonic, photonic, or electronic contexts. We present the exact many-body scattering eigenstate obtained by imposing open boundary conditions. Multiphoton bound states appear in the scattering of two or more photons due to the coupling between the photons and the TLS. Such bound states are shown to have a large effect on scattering of both Fock- and coherent-state wave packets, especially in the intermediate coupling-strength regime. We compare the statistics of the transmitted light with a coherent state having the same mean photon number: as the interaction strength increases, the one-photon probability is suppressed rapidly, and the two- and three-photon probabilities are greatly enhanced due to the many-body bound states. This results in non-Poissonian light.

  13. Entropy and Entanglement Bounds for Reduced Density Matrices of Fermionic States

    NASA Astrophysics Data System (ADS)

    Carlen, Eric A.; Lieb, Elliott H.; Reuvers, Robin

    2016-06-01

    Unlike bosons, fermions always have a non-trivial entanglement. Intuitively, Slater determinantal states should be the least entangled states. To make this intuition precise we investigate entropy and entanglement of fermionic states and prove some extremal and near extremal properties of reduced density matrices of Slater determinantal states.

  14. Fano effect and bound state in continuum in electron transport through an armchair graphene nanoribbon with line defect

    PubMed Central

    2013-01-01

    Electron transport properties in an armchair graphene nanoribbon are theoretically investigated by considering the presence of line defect. It is found that the line defect causes the abundant Fano effects and bound state in continuum (BIC) in the electron transport process, which are tightly dependent on the width of the nanoribbon. By plotting the spectra of the density of electron states of the line defect, we see that the line defect induces some localized quantum states around the Dirac point and that the different localizations of these states lead to these two kinds of transport results. Next, the Fano effect and BIC phenomenon are detailedly described via the analysis about the influence of the structure parameters. According to the numerical results, we propose such a structure to be a promising candidate for graphene nanoswitch. PACS 81.05.Uw, 71.55.-i, 73.23.-b, 73.25.+i PMID:23870061

  15. Quantum dynamics and quantum state transfer between separated nitrogen-vacancy centers embedded in photonic crystal cavities

    NASA Astrophysics Data System (ADS)

    Yang, W. L.; Yin, Z. Q.; Xu, Z. Y.; Feng, M.; Oh, C. H.

    2011-10-01

    We investigate dynamics of a laser-driven and dissipative system consisting of two nitrogen-vacancy (N-V) centers embedded in two spatially separated single-mode nanocavities in a planar photonic crystal (PC). Spontaneous emission from the excited states of the N-V centers can be effectively suppressed by virtue of the Raman transition in the dispersive regime. The system displays a series of damped oscillations under various experimental situations, where we solve the time-dependent Schrödinger equation analytically for arbitrary values of the hopping and PC-N-V coupling strengths. In particular, our results indicate that some special values should be taken for the hopping strength if we hope to have high-fidelity quantum state transfer between the two distant N-V centers. We have also analyzed the relevant entanglement dynamics in the presence of decoherence. The experimental feasibility and challenge are justified using currently available technology.

  16. The structure of Aquifex aeolicus FtsH in the ADP-bound state reveals a C2-symmetric hexamer.

    PubMed

    Vostrukhina, Marina; Popov, Alexander; Brunstein, Elena; Lanz, Martin A; Baumgartner, Renato; Bieniossek, Christoph; Schacherl, Magdalena; Baumann, Ulrich

    2015-06-01

    The crystal structure of a truncated, soluble quadruple mutant of FtsH from Aquifex aeolicus comprising the AAA and protease domains has been determined at 2.96 Å resolution in space group I222. The protein crystallizes as a hexamer, with the protease domain forming layers in the ab plane. Contacts between these layers are mediated by the AAA domains. These are highly disordered in one crystal form, but are clearly visible in a related form with a shorter c axis. Here, adenosine diphosphate (ADP) is bound to each subunit and the AAA ring exhibits twofold symmetry. The arrangement is different from the ADP-bound state of an analogously truncated, soluble FtsH construct from Thermotoga maritima. The pore is completely closed and the phenylalanine residues in the pore line a contiguous path. The protease hexamer is very similar to those described for other FtsH structures. To resolve certain open issues regarding a conserved glycine in the linker between the AAA and protease domains, as well as the active-site switch β-strand, mutations have been introduced in the full-length membrane-bound protein. Activity analysis of these point mutants reveals the crucial importance of these residues for proteolytic activity and is in accord with previous interpretation of the active-site switch and the importance of the linker glycine residue. PMID:26057670

  17. On absence of bound states for weakly attractive δ'-interactions supported on non-closed curves in ℝ2

    NASA Astrophysics Data System (ADS)

    Jex, Michal; Lotoreichik, Vladimir

    2016-02-01

    Let Λ ⊂ ℝ2 be a non-closed piecewise-C1 curve, which is either bounded with two free endpoints or unbounded with one free endpoint. Let u±|Λ ∈ L2(Λ) be the traces of a function u in the Sobolev space H1(ℝ2∖Λ) onto two faces of Λ. We prove that for a wide class of shapes of Λ the Schrödinger operator Hω Λ with δ'-interaction supported on Λ of strength ω ∈ L∞(Λ; ℝ) associated with the quadratic form H 1 ( R 2 ∖ Λ ) ∋ u ↦ ∫ R 2 |" separators=" ∇ u | 2 d x - ∫ Λ ω |" separators=" u + | Λ - u - | Λ | 2 d s has no negative spectrum provided that ω is pointwise majorized by a strictly positive function explicitly expressed in terms of Λ. If, additionally, the domain ℝ2∖Λ is quasi-conical, we show that σ ( Hω Λ ) = [ 0 , + ∞ ) . For a bounded curve Λ in our class and non-varying interaction strength ω ∈ ℝ, we derive existence of a constant ω∗ > 0 such that σ ( Hω Λ ) = [ 0 , + ∞ ) for all ω ∈ (-∞, ω∗]; informally speaking, bound states are absent in the weak coupling regime.

  18. Reynolds stress calculations of homogeneous turbulent shear flow with bounded energy states

    NASA Technical Reports Server (NTRS)

    Speziale, Charles G.; Abid, R.

    1992-01-01

    Reynolds stress calculations of homogeneous turbulent shear flow are conducted with a second-order closure model modified to account for non-equilibrium vortex stretching in the dissipation rate transport equation, as recently proposed by Bernard and Speziale. As with the earlier reported k-epsilon model calculations incorporating this vortex stretching effect, a production-equals-dissipation equilibrium is obtained with bounded turbulent kinetic energy and dissipation. However, this equilibrium is not achieved until the dimensionless time greater than 60, an elapsed time that is at least twice as large as any of those considered in previous numerical and physical experiments on homogeneous shear flow. Direct quantitative comparisons between the model predictions and the results of experiments are quite favorable. In particular, it is shown that the inclusion of this non-equilibrium vortex stretching effect has the capability of explaining the significant range of production to dissipation ratios observed in experiments.

  19. Reynolds stress calculations of homogeneous turbulent shear flow with bounded energy states

    NASA Technical Reports Server (NTRS)

    Speziale, Charles G.; Abid, R.

    1993-01-01

    Reynolds stress calculations of homogeneous turbulent shear flow are conducted with a second-order closure model modified to account for nonequilibrium vortex stretching in the dissipation rate transport equation as recently proposed by Bernard and Speziale (1992). As with the earlier reported K-epsilon model calculations incorporating this vortex stretching effect, a production-equals-dissipation equilibrium is obtained with bounded turbulent kinetic energy and dissipation. However, this equilibrium is now not achieved until the dimensionless time St greater than 60 - an elapsed time that is at least twice as large as any of those considered in previous numerical and physical experiments on homogeneous shear flow. Direct quantitative comparisons between the model predictions and the results of experiments are quite favorable. In particular, it is shown that the inclusion of this nonequilibrium vortex stretching effect has the capability of explaining the significant range of production to dissipation ratios observed in experiments.

  20. Heavy fermion bound states for diphoton excess at 750 GeV — collider and cosmological constraints

    NASA Astrophysics Data System (ADS)

    Han, Chengcheng; Ichikawa, Koji; Matsumoto, Shigeki; Nojiri, Mihoko M.; Takeuchi, Michihisa

    2016-04-01

    A colored heavy particle with sufficiently small width may form non-relativistic bound states when they are produced at the large hadron collider (LHC), and they can annihilate into a diphoton final state. The invariant mass of the diphoton would be around twice of the colored particle mass. In this paper, we study if such bound state can be responsible for the 750 GeV diphoton excess reported by ATLAS and CMS. We found that the best-fit signal cross section is obtained for the SU(2) L singlet colored fermion X with Y X = 4 /3. Having such an exotic hypercharge, the particle is expected to decay through some higher dimensional operators, consistent with the small width assumption. The decay of X may involve a stable particle χ, if both X and χ are odd under some conserved Z 2 symmetry. In that case, the particle X suffers from the constraints of jets + missing E T searches by ATLAS and CMS at 8 TeV and 13 TeV. We found that such a scenario still survives if the mass difference between X and χ is above ˜ 30 GeV for m X ˜ 375 GeV. Even assuming pair annihilation of χ is small, the relic density of χ is small enough if the mass difference between X and χ is smaller than ˜ 40 GeV.

  1. Explanation of the {delta}{sub 5/2{sup -}}(1930) as a {rho}{delta} bound state

    SciTech Connect

    Gonzalez, P.; Oset, E.; Vijande, J.

    2009-02-15

    We use the {rho}{delta} interaction in the hidden gauge formalism to dynamically generate N* and {delta}* resonances. We show, through a comparison of the results from this analysis and from a quark model study with data, that the {delta}{sub 5/2{sup -}}(1930), {delta}{sub 3/2{sup -}}(1940), and {delta}{sub 1/2{sup -}}(1900) resonances can be assigned to {rho}{delta} bound states. More precisely the {delta}{sub 5/2{sup -}}(1930) can be interpreted as a {rho}{delta} bound state whereas the {delta}{sub 3/2{sup -}}(1940) and {delta}{sub 1/2{sup -}}(1900) may contain an important {rho}{delta} component. This interpretation allows for a solution of a long-standing puzzle concerning the description of these resonances in constituent quark models. In addition we also obtain degenerate J{sup P}=1/2{sup -},3/2{sup -},5/2{sup -} N* states but their assignment to experimental resonances is more uncertain.

  2. A search for deeply-bound kaonic nuclear state at the J-PARC E15 experiment

    NASA Astrophysics Data System (ADS)

    Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kawasaki, S.; Kienle, P.; Kou, H.; Ma, Y.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Poli Lener, M.; Romero Vidal, A.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Vazquez Doce, O.; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    2013-09-01

    The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, KbarNN, by the in-flight He3(K-,N) reaction. The exclusive measurement will be performed by a simultaneous measurement of the missing mass using the forward neutron or proton, and the invariant mass via the expected decay, e.g. K-pp→Λp→pπ-p. In this report, an overview of the experiment and an analysis of engineering runs performed in February and June are presented.

  3. Bi donor hyperfine state populations studied by optical transitions of donor bound excitons in enriched {sup 28}Si

    SciTech Connect

    Ilkhchy, K. Saeedi; Steger, M.; Thewalt, M. L. W.; Abrosimov, N.; Riemann, H.; Becker, P.; Pohl, H.-J.

    2013-12-04

    We report on the first optical studies of Bi donor bound excitons in {sup 28}Si, using absorption rather than emission spectroscopy, and a new noncontact photoconductivity method which has much higher sensitivity and spectral resolution than photoluminescence spectroscopy. Individual hyperfine components of this potential semiconductor qubit can be resolved under an applied magnetic field, and we find that strong nonresonant optical hyperpolarization towards both the I{sub z} = +9/2 and −9/2 hyperfine states can be observed, depending on the intensity of the above-gap excitation.

  4. Bound states in two-dimensional spin systems near the Ising limit: A quantum finite-lattice study

    SciTech Connect

    Dusuel, Sebastien; Kamfor, Michael; Schmidt, Kai Phillip; Thomale, Ronny; Vidal, Julien

    2010-02-01

    We analyze the properties of low-energy bound states in the transverse-field Ising model and in the XXZ model on the square lattice. To this end, we develop an optimized implementation of perturbative continuous unitary transformations. The Ising model is studied in the small-field limit which is found to be a special case of the toric code model in a magnetic field. To analyze the XXZ model, we perform a perturbative expansion about the Ising limit in order to discuss the fate of the elementary magnon excitations when approaching the Heisenberg point.

  5. A Search for deeply-bound Kaonic nuclear state at the J-PARC E15 experiment

    SciTech Connect

    Sada, Y.

    2011-10-21

    The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, K-barNN, by the in-flight {sup 3}He(K{sup -},N) reaction. The exclusive measurement can be performed by a simultaneous measurement of the missing mass using the primary neutron or proton, and the invariant mass via the expected decay, e.g. K{sup -}pp{yields}{Lambda}p{yields}p{pi}{sup -}p. an overview of the experiment and the preparation status are reported.

  6. The ground state and doubly-excited 1,3P° states of hot-dense plasma-embedded Li+ ions

    NASA Astrophysics Data System (ADS)

    Kar, S.; Ho, Y. K.

    2007-07-01

    We have investigated the ground state and the doubly excited 1,3P^circ resonance states of plasma-embedded Li+ ion. The plasma effect is taken care of by using a screened Coulomb potential obtained from the Debye model. A correlated wave function has been used to represent the correlation effect between the charged particles. The ground state of Li+ in plasmas for different screening parameters has been estimated in the framework of Rayleigh-Ritz variational principle. In addition, a total of 18 resonances (9 each for ^1P^circ and ^3P^circ states) below the n=2 Li+ thresholds has been estimated by calculating the density of states using the stabilization method. For each spin state, this includes four members in the 2snp+ (2≤ n ≤ 5) series, three members in the 2snp- (3≤ n ≤ 5) series, and two members in the 2pnd (n=3, 4) series. The resonance energies and widths for various Debye parameters ranging from infinity to a small value for these 1,3P^circ resonance states along with the ground state energies of Li+ and the Li2+ (1S), Li2+ (2S) threshold energies are reported. Furthermore, the wavelengths for the photo-absorption of lithium ion from its ground state to such ^1P^circ resonance states for different Debye lengths are also reported.

  7. Magnetic anisotropy in Shiba bound states across a quantum phase transition

    NASA Astrophysics Data System (ADS)

    Hatter, Nino; Heinrich, Benjamin W.; Ruby, Michael; Pascual, Jose I.; Franke, Katharina J.

    2015-11-01

    The exchange coupling between magnetic adsorbates and a superconducting substrate leads to Shiba states inside the superconducting energy gap and a Kondo resonance outside the gap. The exchange coupling strength determines whether the quantum many-body ground state is a Kondo singlet or a singlet of the paired superconducting quasiparticles. Here we use scanning tunnelling spectroscopy to identify the different quantum ground states of manganese phthalocyanine on Pb(111). We observe Shiba states, which are split into triplets by magnetocrystalline anisotropy. Their characteristic spectral weight yields an unambiguous proof of the nature of the quantum ground state. Our results provide experimental insights into the phase diagram of a magnetic impurity on a superconducting host and shine light on the effects induced by magnetic anisotropy on many-body interactions.

  8. Magnetic anisotropy in Shiba bound states across a quantum phase transition

    PubMed Central

    Hatter, Nino; Heinrich, Benjamin W.; Ruby, Michael; Pascual, Jose I.; Franke, Katharina J.

    2015-01-01

    The exchange coupling between magnetic adsorbates and a superconducting substrate leads to Shiba states inside the superconducting energy gap and a Kondo resonance outside the gap. The exchange coupling strength determines whether the quantum many-body ground state is a Kondo singlet or a singlet of the paired superconducting quasiparticles. Here we use scanning tunnelling spectroscopy to identify the different quantum ground states of manganese phthalocyanine on Pb(111). We observe Shiba states, which are split into triplets by magnetocrystalline anisotropy. Their characteristic spectral weight yields an unambiguous proof of the nature of the quantum ground state. Our results provide experimental insights into the phase diagram of a magnetic impurity on a superconducting host and shine light on the effects induced by magnetic anisotropy on many-body interactions. PMID:26603561

  9. Equation of state of dense nuclear matter and an upper bound on neutron star masses

    NASA Astrophysics Data System (ADS)

    Negi, P. S.; Durgapal, M. C.

    2001-02-01

    We have discussed, in general, the important physical parameters, like maximum mass, radius, and the minimum rotation period of self-bound, causally consistent, and pulsationally stable neutron stars (Q-star models) by using a realistic stiff EOS (such that, the speed of sound, v~ P, or nP=K(E-E), where K<= 1 and n =1/(1-2N) where P and E represent respectively, the pressure and the energy-density, and E is the value of E at the surface (r = a) of the configuration) within the two constraints imposed by: (i) The minimum rotation period, P, for the pulsar known to date corresponds to 1.558 ms, and (ii) The maximum number density anywhere inside the structure for the models described as Q-stars cannot exceed ~ 1 nucleon/fm^3. By using the empirical formula given by Koranda, Stergioulas and Friedman (1997) (KSF-formula), and imposing constraint (i), we have obtained an upper bound of M ≅ 7.76 M radius a≅ 32.5 km, and the central energy-density around 2.17 × 10^14 g cm^-3 (for n =1.01). Constraint (ii) provides the minimum rotation period, P ~ 0.489 ms for the maximum mass M ~ 2.4 M_solar, and the central energy-density around 2.20 × 10^15 g cm^-3 (for n =1.01). The speed of sound at the centre of these models approaches ~ 99% of the speed of light `c' (in the vacuum) and vanishes at the surface of the configuration together with pressure. If we relax the maximum Kepler frequency imposed by the fastest rotating pulsar known to date (constraint (i)), in view of certain observational effects and theoretical evidences, and allow the present EOS to produce larger rotation rates than the 1.558 ms pulsar, the maximum mass of the non-rotating model drops down to a value ~ 7.2 M_solar. The higher values of masses (>= 7 M_solar) and radii (~ 31-32 km) obtained in this study imply that these models may represent the massive compact objects like Cyg X-1, Cyg XR-1, LMC X-3, and others which are known as black hole candidates (BHCs). This study also suggest that the strongest

  10. Rovibrational energy transfer in the He-C3 collision: potential energy surface and bound states.

    PubMed

    Denis-Alpizar, Otoniel; Stoecklin, Thierry; Halvick, Philippe

    2014-02-28

    We present a four-dimensional potential energy surface (PES) for the collision of C3 with He. Ab initio calculations were carried out at the coupled-cluster level with single and double excitations and a perturbative treatment of triple excitations, using a quadruple-zeta basis set and mid-bond functions. The global minimum of the potential energy is found to be -26.9 cm(-1) and corresponds to an almost T-shaped structure of the van der Waals complex along with a slightly bent configuration of C3. This PES is used to determine the rovibrational energy levels of the He-C3 complex using the rigid monomer approximation (RMA) and the recently developed atom-rigid bender approach at the Close Coupling level (RB-CC). The calculated dissociation energies are -9.56 cm(-1) and -9.73 cm(-1), respectively at the RMA and RB-CC levels. This is the first theoretical prediction of the bound levels of the He-C3 complex with the bending motion. PMID:24588178

  11. Electronic transport through a Majorana bound state coupled to a T-shaped quantum-dot system with Coulomb interaction

    NASA Astrophysics Data System (ADS)

    Huo, Dong-Ming

    2016-07-01

    Using the Green's function technique, we respectively investigate the electron transport properties of two spin components through the system of a T-shaped double quantum dot structure coupled to a Majorana bound state, in which only one quantum dot is connected with two metallic leads. We explore the interplay between the Fano effect and the MBSs for different dot-MBS coupling strength λ, dot-dot coupling strength t, and MBS-MBS coupling strength ɛM in the noninteracting case. Then the Coulomb interaction and magnetic field effect on the conductance spectra are investigated. Our results indicate that G↓(ω) is not affected by the Majorana bound states, but a "0.5" conductance signature occurs in the vicinities of Fermi level of G↑(ω). This robust property persists for a wide range of dot-dot coupling strength and dot-MBS coupling strength, but it can be destroyed by Coulomb interaction in quantum dots. By adjusting the size and direction of magnetic field around the quantum dots, the "0.5" conductance signature damaged by U can be restored. At last, the spin magnetic moments of two dots by applying external magnetic field are also predicted.

  12. A hierarchy of ``meson'' bound state excitations in the 1D ferromagnetic Ising chain CoNb2O6

    NASA Astrophysics Data System (ADS)

    Morris, Christopher; Koopayeh, Seyed; Ghosh, Anirban; Tchernyshyov, Oleg; McQueen, Tyrel M.; Armitage, N. Peter; Valdés Aguilar, Rolando; Krizan, Jason; Cava, Robert J.

    2014-03-01

    The quantum magnet CoNb2O6 was recently demonstrated to be an excellent realization of the one-dimensional ferromagnetic Ising spin chain. Low energy spin-flip excitations in the chains were recently observed via inelastic neutron scattering.[2] The energy spectrum of these excitations was shown to have a interesting energy scaling governed by symmetries of the E8 exceptional Lie group. Here, time-domain terahertz spectroscopy (TDTS) is used to investigate these optically active spin flip excitations in CoNb2O6. A series of nine spin flip bound states is observed, whose energies can be modeled exceedingly well by the Airy function solutions to a 1D Schrödinger equation. Additionally, a novel bound state of excitations on neighboring chains is observed just below the onset of a two particle continuum. Work supported by The Institute of Quantum Matter under DOE grant DE-FG02-08ER46544 and by the Gordon and Betty Moore Foundation through Grant GBMF2628.

  13. Effective preparation of the N-dimension spin Greenberger-Horne-Zeilinger state with quantum dots embedded in microcavities

    NASA Astrophysics Data System (ADS)

    Kang, Yi-Hao; Xia, Yan; Lu, Pei-Min; Song, Jie

    2016-07-01

    We propose a scheme for preparation of the N-dimension spin Greenberger-Horne-Zeilinger state by exploiting quantum dots (QDs) embedded in microcavities. Numerically analysed results show that with the spin-selective photon reflection from the cavity, we can complete the scheme assisted by one polarized photon with high fidelity and 100% successful probability in principle. Furthermore, the set-up is just composed of simple linear optical elements, delay lines and conventional photon detectors, which are feasible with existing experimental technology. Moreover, QDs have numerous admirable features in weak-coupling regime, which are practicable in realistic cavity quantum electrodynamics system shown by previous numerical simulations and experiments. Therefore, our scheme might be realized in near future.

  14. Reconciling simulated melting and ground-state properties of metals with a modified embedded-atom method potential

    NASA Astrophysics Data System (ADS)

    Sushko, G. B.; Verkhovtsev, A. V.; Kexel, Ch; Korol, A. V.; Schramm, S.; Solov'yov, A. V.

    2016-04-01

    We propose a modification of the embedded-atom method-type potential aiming at reconciling simulated melting and ground-state properties of metals by means of classical molecular dynamics. Considering titanium, magnesium, gold, and platinum as case studies, we demonstrate that simulations performed with the modified force field yield quantitatively correctly both the melting temperature of the metals and their ground-state properties. It is shown that the accounting for the long-range interatomic interactions noticeably affects the melting point assessment. The introduced modification weakens the interaction at interatomic distances exceeding the equilibrium one by a characteristic vibration amplitude defined by the Lindemann criterion, thus allowing for the correct simulation of melting, while keeping its behavior in the vicinity of the ground state minimum. The modification of the many-body potential has a general nature and can be applicable to metals with different characteristics of the electron structure as well as for many different molecular and solid state systems experiencing phase transitions.

  15. Solvable light-front model of the electromagnetic form factor of the relativistic two-body bound state in 1+1 dimensions

    SciTech Connect

    Mankiewicz, L. ); Sawicki, M. )

    1989-11-15

    Within a relativistically correct yet analytically solvable model of light-front quantum mechanics we construct the electromagnetic form factor of the two-body bound state and we study the validity of the static approximation to the full form factor. Upon comparison of full form factors calculated for different values of binding energy we observe an unexpected effect that for very strongly bound states further increase in binding leads to an increase in the size of the bound system. A similar effect is found for another quantum-mechanical model of relativistic dynamics.

  16. A Transformation Approach to Optimal Control Problems with Bounded State Variables

    NASA Technical Reports Server (NTRS)

    Hanafy, Lawrence Hanafy

    1971-01-01

    A technique is described and utilized in the study of the solutions to various general problems in optimal control theory, which are converted in to Lagrange problems in the calculus of variations. This is accomplished by mapping certain properties in Euclidean space onto closed control and state regions. Nonlinear control problems with a unit m cube as control region and unit n cube as state region are considered.

  17. Asymptotic normalization coefficients of resonant and bound states from the phase shifts for α α and α 12C scattering

    NASA Astrophysics Data System (ADS)

    Orlov, Yu. V.; Irgaziev, B. F.; Nikitina, L. I.

    2016-01-01

    Recently we have published a paper [Irgaziev, Phys. Rev. C 91, 024002 (2015), 10.1103/PhysRevC.91.024002] where the S -matrix pole method (SMP), which is only valid for resonances, has been developed to derive an explicit expression for the asymptotic normalization coefficient (ANC) and is applied to the low-energy resonant states of nucleon +α and α +12C systems. The SMP results are compared with the effective-range expansion method (EFE) results. In the present paper the SMP and EFE plus the Padé approximation are applied to study the excited 2+ resonant states of 9Be. A contradiction is found between descriptions of the experimental phase shift data for α α scattering and of the 9Be resonant energy for 2+ state. Using the EFE method, we also calculate the ANC for the 9Be ground 0+ state with a very small width. This ANC agrees well with the value calculated using the known analytical expression for narrow resonances. In addition, for the α +12C states 1- and 3- the SMP results are compared with the Padé approximation results. We find that the Padé approximation improves a resonance width description compared with the EFE results. The EFE method is also used to calculate the ANCs for the bound 0mml:mprescripts>O ground 0+ state and for the excited 1- and 2+ levels, which are situated near the threshold of α +12C channel.

  18. Magic-Angle Spinning Solid-State NMR Spectroscopy of Nanodisc– Embedded Human CYP3A4†

    PubMed Central

    Kijac, Aleksandra; Li, Ying; Sligar, Stephen G.; Rienstra, Chad M.

    2008-01-01

    Cytochrome P450 (CYP) 3A4 contributes to the metabolism of approximately 50% of commercial drugs by oxidizing a large number of structurally diverse substrates. Like other endoplasmic reticulum-localized P450s, CYP3A4 contains a membrane-anchoring N-terminal helix and a significant number of hydrophobic domains, important for the interaction between CYP3A4 and the membrane. Although the membrane affects specificity of CYP3A4 ligand binding, the structural details of the interaction have not been revealed so far because x-ray crystallography studies are available only for the soluble domain of CYP3A4. Here we report sample preparation and initial magic-angle spinning (MAS) solid-state NMR (SSNMR) of CYP3A4 (Δ3−12) embedded in a nanoscale membrane bilayer, or Nanodisc. The growth protocol yields ∼2.5 mg of the enzymatically active, uniformly 13C, 15N-enriched CYP3A4 from a liter of growth medium. Polyethylene glycol 3350-precipitated CYP3A4 in Nanodiscs yields spectra of high resolution and sensitivity, consistent with a folded, homogeneous protein. CYP3A4 in Nanodiscs remains enzymatically active throughout the precipitation protocol as monitored by bromocriptine binding. The 13C line widths measured from 13C-13C 2D chemical shift correlation spectra are ∼0.5 ppm. The secondary structure distribution within several amino acid types determined from 13C chemical shifts is consistent with the ligand-free x-ray structures. These results demonstrate that MAS SSNMR can be performed on Nanodisc-embedded membrane proteins in a folded, active state. The combination of SSNMR and Nanodisc methodologies opens up new possibilities for obtaining structural information on CYP3A4 and other integral membrane proteins with full retention of functionality. PMID:17985934

  19. Unified calculation of generalized oscillator strength of argon ranging from bound to continuum states

    NASA Astrophysics Data System (ADS)

    Gao, Xiang; Jin, Rui; Zeng, De-Ling; Han, Xiao-Ying; Yan, Jun; Li, Jia-Ming

    2015-11-01

    The electron and photon scattering data of an atom are crucial for many scientific fields, including plasma physics, astrophysics, and so on. For high enough but nonrelativistic incident energies, the first Born approximation is applicable for calculating these data, in which the key physics quantity is the generalized oscillator strength (GOS). In high-energy electron impact excitation processes, atoms will be excited into various excited states including strongly perturbed Rydberg and adjacent continuum states. How to calculate these quantities of a nontrivial many-electron atom rapidly and accurately is still a great challenge. Based on our eigenchannel R -matrix method R -eigen, we further extend it to calculate the GOS of a whole channel in an atom, which includes all Rydberg and adjacent continuum states. The Jπ=1- states of argon are chosen as an illustrating example. The calculation results are in good agreement with the available benchmark absolute experimental measurements. The calculated eigenchannel GOS matrix elements are smooth functions of the excitation energy and momentum transfer. From such smooth eigenchannel GOS matrix elements, we can obtain the GOS of any specific excited state through multichannel quantum defect theory, e.g., infinite Rydberg (including a strongly perturbed one), autoionization, and continuum states.

  20. Characteristics of d + α Bound and Resonant States from Analytic Continuation of the Effective-Range Expansion

    NASA Astrophysics Data System (ADS)

    Blokhintsev, L. D.; Nikitina, L. I.; Orlov, Yu. V.; Savin, D. A.

    2014-08-01

    In the present work one- and two-channel approaches using the expansion of the effective-range function K( E) in powers of energy E are applied to obtain the asymptotic normalization coefficients (ANCs) and vertex constants (VCs) for the d + α system. The coefficients of the K( E) expansion are found by fitting the d α phase shifts. By analytic continuation of K( E) thus obtained to the corresponding poles the ANCs and VCs for D wave d α resonances with J π = 1+, 2+, 3+ are calculated for the first time. The 1+-resonance and the bound state of 6Li ( J π = 1+) are considered jointly in the two-channel ( S + D) effective-range approach and the ANCs and VCs for the ground 6Li state are found.

  1. Binding Polymorphism in the DNA Bound State of the Pdx1 Homeodomain

    PubMed Central

    Babin, Volodymyr; Wang, Dongli; Rose, Robert B.; Sagui, Celeste

    2013-01-01

    The subtle effects of DNA-protein recognition are illustrated in the homeodomain fold. This is one of several small DNA binding motifs that, in spite of limited DNA binding specificity, adopts crucial, specific roles when incorporated in a transcription factor. The homeodomain is composed of a 3-helix domain and a mobile N-terminal arm. Helix 3 (the recognition helix) interacts with the DNA bases through the major groove, while the N-terminal arm becomes ordered upon binding a specific sequence through the minor groove. Although many structural studies have characterized the DNA binding properties of homeodomains, the factors behind the binding specificity are still difficult to elucidate. A crystal structure of the Pdx1 homeodomain bound to DNA (PDB 2H1K) obtained previously in our lab shows two complexes with differences in the conformation of the N-terminal arm, major groove contacts, and backbone contacts, raising new questions about the DNA recognition process by homeodomains. Here, we carry out fully atomistic Molecular Dynamics simulations both in crystal and aqueous environments in order to elucidate the nature of the difference in binding contacts. The crystal simulations reproduce the X-ray experimental structures well. In the absence of crystal packing constraints, the differences between the two complexes increase during the solution simulations. Thus, the conformational differences are not an artifact of crystal packing. In solution, the homeodomain with a disordered N-terminal arm repositions to a partially specific orientation. Both the crystal and aqueous simulations support the existence of different stable binding conformers identified in the original crystallographic data with different degrees of specificity. We propose that protein-protein and protein-DNA interactions favor a subset of the possible conformations. This flexibility in DNA binding may facilitate multiple functions for the same transcription factor. PMID:23950697

  2. Energies and excited-state dynamics of 1Bu+, 1Bu- and 3Ag- states of carotenoids bound to LH2 antenna complexes from purple photosynthetic bacteria

    NASA Astrophysics Data System (ADS)

    Christiana, Rebecca; Miki, Takeshi; Kakitani, Yoshinori; Aoyagi, Shiho; Koyama, Yasushi; Limantara, Leenawaty

    2009-10-01

    Time-resolved pump-probe stimulated-emission and transient-absorption spectra were recorded after excitation with ˜30 fs pulses to the 1Bu+(0) and optically-forbidden diabatic levels of carotenoids, neurosporene, spheroidene and lycopene having n = 9-11 double bonds, bound to LH2 antenna complexes from Rhodobacter sphaeroides G1C, 2.4.1 and Rhodospirillum molischianum. The low-energy shift of stimulated emission from the covalent 1Bu-(0) and 3Ag-(0) levels slightly larger than that from the ionic 1Bu+(0) state suggests the polarization, whereas more efficient triplet generation suggests the twisting of the conjugated chain in Cars bound to the LH2 complexes, when compared to Cars free in solution.

  3. Observation of bound and unbound 1- states in 208Pb by particle spectroscopy

    NASA Astrophysics Data System (ADS)

    Heusler, Andreas

    2015-02-01

    Using the Q3D magnetic spectrograph of the Maier-Leibnitz-Labaratorium at Garching (Germany), experiments on the 208Pb(d,d'), the 207Pb(d,p), the resonant and the non-resonant 208Pb(p,p') reactions were performed. The 208Pb(p,p') reaction was investigated near all seven known isobaric analog resonances in 209Bi. The excitation energies of about 300 states in 208Pb at Ex < 8MeV were determined with an accuracy of about 100 eV. The mean distance between states in 208Pb is about 10keV up to the neutron threshold (S(n) = 7368 keV). The number of 1- states observed by particle spectroscopy up to the proton threshold (S(p) = 8.00 MeV) is close to the number predicted by the schematic shell model without residual interaction. The structure of several 1- states is deduced from particle spectroscopy. Four out of the seven lowest 1- states contain about 80% strength of a single configuration.

  4. Bound and Unbound: Stabilizing the Anionic States of Adamantane through Functionalization

    NASA Astrophysics Data System (ADS)

    Pozun, Zachary; Voora, Vamsee; Falcetta, Michael; Jordan, Kenneth

    2014-03-01

    Adamantane is the simplest diamondoid, which are nanostructures of carbon with a diamond-like cage structure. Although diamondoids have been reported to have negative electron affinities (EA), calculating an EA for an unbound anion is not straightforward because the localized anion state is strongly coupled to the continuum. In order to determine the energy and lifetime of temporary anions, we apply the stabilization method, where the exponents of the diffuse basis functions centered on the carbon atoms are scaled during equation-of-motion calculations; the energies of the anionic states are relatively insensitive to the scaling factor as compared to the continuum states. We use this method in order to identify temporary anion states and their associated energies and lifetimes. We also demonstrate that these states can be tuned in energy based substituting the adamantane cage with substituents that either withdraw or donate charge into the carbon-carbon backbone. Thus, the unique optoelectric properties of small diamondoids can be properly calculated and easily tuned. ZDP acknowledges support through NSF grant no. OCI-1225384.

  5. Semiclassical quantization of bound and quasistationary states beyond the adiabatic approximation

    SciTech Connect

    Benderskii, V.A.; Vetoshkin, E.V.; Kats, E.I.

    2004-06-01

    We examine one important (and previously overlooked) aspect of well-known crossing diabatic potentials or Landau-Zener (LZ) problem. We derive the semiclassical quantization rules for the crossing diabatic potentials with localized initial and localized or delocalized final states, in the intermediate energy region, when all four adiabatic states are coupled and should be taken into account. We found all needed connection matrices and present the following analytical results: (i) in the tunneling region, the splittings of vibrational levels are represented as a product of the splitting in the lower adiabatic potential and the nontrivial function depending on the Massey parameter; (ii) in the overbarrier region, we find specific resonances between the levels in the lower and in the upper adiabatic potentials and, in that condition, independent quantizations rules are not correct; (iii) for the delocalized final states (decay lower adiabatic potential), we describe quasistationary states and calculate the decay rate as a function of the adiabatic coupling; and (iv) for the intermediate energy regions, we calculate the energy level quantization, which can be brought into a compact form by using either adiabatic or diabatic basis set (in contrast to the previous results found in the Landau diabatic basis). Applications of the results may concern the various systems; e.g., molecules undergoing conversion of electronic states, radiationless transitions, or isomerization reactions.

  6. Effect of a Culture-Based Screening Algorithm on Tuberculosis Incidence in Immigrants and Refugees Bound for the United States

    PubMed Central

    Liu, Yecai; Posey, Drew L.; Cetron, Martin S.; Painter, John A.

    2015-01-01

    Background Before 2007, U.S.-bound immigrants and refugees were screened for tuberculosis (TB) by a smear-based algorithm that could not diagnose smear-negative and culture-positive TB. In 2007, the Centers for Disease Control and Prevention began to implement a culture-based algorithm. Objective To evaluate the effect of the culture-based algorithm on preventing the importation of TB to the United States by immigrants and refugees from foreign countries. Design Population-based, cross-sectional study. Setting Panel physician sites for overseas medical examination. Patients Immigrants and refugees with TB. Measurements Comparison of the increase of smear-negative and culture-positive TB cases diagnosed overseas among immigrants and refugees by the culture-based algorithm with the decline of reported TB cases among foreign-born persons within 1 year after arrival in the United States from 2007 to 2012. Results Of the 3 212 421 arrivals of immigrants and refugees from 2007 to 2012, 1 650 961 (51.4%) were screened by the smear-based algorithm and 1 561 460 (48.6%) were screened by the culture-based algorithm. Among the 4032 TB cases diagnosed by the culture-based algorithm, 2195 (54.4%) were smear-negative and culture-positive. Before implementation (2002 to 2006), the annual number of reported TB cases among foreign-born persons within 1 year after arrival was relatively constant (range, 1424 to 1626 cases; mean, 1504 cases) but decreased from 1511 to 940 cases during implementation (2007 to 2012). During the same period, the annual number of smear-negative and culture-positive TB cases diagnosed overseas among U.S.-bound immigrants and refugees by the culture-based algorithm increased from 4 in 2007 to 629 in 2012. Limitation This analysis did not control for the decline in new arrivals of nonimmigrant visitors to the United States and the decrease of incidence of TB in their countries of origin. Conclusion Implementation of the culture-based algorithm in U.S.-bound

  7. Molecular parameters for weakly bound 2g(aa, ab) and {0}_{u}^{-}(ab) states of molecular iodine and dipole moment functions of transitions to these states

    NASA Astrophysics Data System (ADS)

    Baturo, V. V.; Cherepanov, I. N.; Lukashov, S. S.; Poretsky, S. A.; Pravilov, A. M.

    2016-06-01

    Weakly bound valence states of 2g symmetry, correlating with the I(2 P 3/2) + I(2 P 3/2) (aa) and I(2 P 3/2) + I(2 P 1/2) (ab) dissociation limits, as well as {0}u-(ab) state, were studied using vibrationally resolved luminescence spectra corresponding to transitions from δ2u(3 P 2) and g {0}g-(3 P 1) ion-pair states, in molecular iodine, respectively, populated using a three-step three-color laser excitation scheme. Spectroscopic constants and potential energy curves of the valence states are determined for the first time. Dipole moment functions of δ2u → 2g(aa, ab) and g {0}g- → {0}u-(ab) transitions are found to exponentially decrease.

  8. Photonic realization of topologically protected bound states in domain-wall waveguide arrays

    NASA Astrophysics Data System (ADS)

    Lee-Thorp, J. P.; Vukićević, I.; Xu, X.; Yang, J.; Fefferman, C. L.; Wong, C. W.; Weinstein, M. I.

    2016-03-01

    We present an analytical theory of topologically protected photonic states for the two-dimensional Maxwell equations for a class of continuous periodic dielectric structures, modulated by a domain wall. We further numerically confirm the applicability of this theory for three-dimensional structures.

  9. Emergence of a Kondo singlet state with Kondo temperature well beyond 1000 K in a proton-embedded electron gas

    NASA Astrophysics Data System (ADS)

    Takada, Yasutami; Maezono, Ryo; Yoshizawa, Kanako

    2015-10-01

    Hydrogen in metals has attracted much attention for a long time from both basic scientific and technological points of view. Its electronic state has been investigated in terms of a proton embedded in the electron gas mostly by the local density approximation (LDA) to the density functional theory. At high electronic densities, it is well described by a bare proton H+ screened by metallic electrons (charge resonance), while at low densities two electrons are localized at the proton site to form a closed-shell negative ion H- protected from surrounding metallic electrons by the Pauli exclusion principle. However, no details are known about the transition from H+ to H- in the intermediate-density region. Here, by accurately determining the ground-state electron distribution n (r ) by the use of LDA and diffusion Monte Carlo simulations with the total electron number up to 170, we obtain a complete picture of the transition, in particular, a sharp transition from short-range H+ screening charge resonance to long-range Kondo-type spin-singlet resonance, the emergence of which is confirmed by the presence of an anomalous Friedel oscillation characteristic to the Kondo singlet state with the Kondo temperature TK well beyond 1000 K. This study not only reveals interesting competition between charge and spin resonances, enriching the century-old paradigm of metallic screening to a point charge, but also discovers a high-TK system long sought in relation to the development of exotic superconductivity in the quantum critical regime.

  10. Lateral quantization of two-dimensional electron states by embedded Ag nanocrystals

    NASA Astrophysics Data System (ADS)

    Van Haesendonck, Chris; Schouteden, Koen

    2013-03-01

    We show that quantization of image-potential state (IS)electrons above the surface of nanostructures can be experimentally achieved by Ag nanocrystals that appear as stacking fault tetrahedrons (SFTs) at Ag(111) surfaces. By means of cryogenic scanning tunneling spectroscopy the n = 1 IS of the Ag(111) surface is revealed to split up in discrete energy levels, which is accompanied by the formation of pronounced standing wave patterns that directly reflect the eigenstates of the SFT surface. The IS confinement behavior is compared to that of the surface state electrons in the SFT surface and can be directly linked to the particle-in-a-box model. ISs provide a novel playground for investigating quantum size effects and defect induced scattering above nanostructured surfaces. This work has been supported by the Research Foundation - Flanders (FWO, Belgium). K.S. is a postdoctoral researcher of the FWO.

  11. Lateral Quantization of Two-Dimensional Electron States by Embedded Ag Nanocrystals

    NASA Astrophysics Data System (ADS)

    Schouteden, K.; Van Haesendonck, C.

    2012-02-01

    We show that quantization of image-potential state (IS) electrons above the surface of nanostructures can be experimentally achieved by Ag nanocrystals that appear as stacking-fault tetrahedrons (SFTs) at Ag(111) surfaces. By means of cryogenic scanning tunneling spectroscopy, the n=1 IS of the Ag(111) surface is revealed to split up in discrete energy levels, which is accompanied by the formation of pronounced standing wave patterns that directly reflect the eigenstates of the SFT surface. The IS confinement behavior is compared to that of the surface state electrons in the SFT surface and can be directly linked to the particle-in-a-box model. ISs provide a novel playground for investigating quantum size effects and defect-induced scattering above nanostructured surfaces.

  12. Probing transfer to unbound states of the ejectile with weakly bound

  13. NASA Astrophysics Data System (ADS)

    Pandit, S. K.; Shrivastava, A.; Mahata, K.; Keeley, N.; Parkar, V. V.; Rout, P. C.; Ramachandran, K.; Martel, I.; Palshetkar, C. S.; Kumar, A.; Chatterjee, A.; Kailas, S.

    2016-06-01

    The two-step process of transfer followed by breakup is explored by measuring a rather complete set of exclusive data for reaction channels populating states in the ejectile continua of the states of the ejectile.

  14. The Search for Deeply Bound Kaonic Nuclear States at J-Parc

    NASA Astrophysics Data System (ADS)

    Hiraiwa, T.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Iio, M.; Iliescu, M.; Inoue, K.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kienle, P.; Kou, H.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Pietreanu, D.; Lener, M. Poli; Vidal, A. Romero; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Doce, O. Vazquez; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    The J-PARC E15 experiment aims to search for the lightest kaonic nuclear states, namely K-pp, using in-flight (K-, n) reaction on 3He. In this experiment, the missing mass in the (K-, n) reaction and the invariant mass of the decay such as K-pp → Λp → pπ-p will be measured simultaneously. In this article, the experimental feature and the present status are presented.

  15. Quadratic Zeeman effect for hydrogen: A method for rigorous bound-state error estimates

    SciTech Connect

    Fonte, G.; Falsaperla, P. ); Schiffrer, G. ); Stanzial, D. )

    1990-06-01

    We present a variational method, based on direct minimization of energy, for the calculation of eigenvalues and eigenfunctions of a hydrogen atom in a strong uniform magnetic field in the framework of the nonrelativistic theory (quadratic Zeeman effect). Using semiparabolic coordinates and a harmonic-oscillator basis, we show that it is possible to give rigorous error estimates for both eigenvalues and eigenfunctions by applying some results of Kato (Proc. Phys. Soc. Jpn. 4, 334 (1949)). The method can be applied in this simple form only to the lowest level of given angular momentum and parity, but it is also possible to apply it to any excited state by using the standard Rayleigh-Ritz diagonalization method. However, due to the particular basis, the method is expected to be more effective, the weaker the field and the smaller the excitation energy, while the results of Kato we have employed lead to good estimates only when the level spacing is not too small. We present a numerical application to the {ital m}{sup {ital p}}=0{sup +} ground state and the lowest {ital m}{sup {ital p}}=1{sup {minus}} excited state, giving results that are among the most accurate in the literature for magnetic fields up to about 10{sup 10} G.

  16. Helical order in one-dimensional magnetic atom chains and possible emergence of Majorana bound states

    NASA Astrophysics Data System (ADS)

    Kim, Younghyun; Cheng, Meng; Bauer, Bela; Lutchyn, Roman M.; Das Sarma, S.

    2014-08-01

    We theoretically obtain the phase diagram of localized magnetic impurity spins arranged in a one-dimensional chain on top of a one- or two-dimensional electron gas. The interactions between the spins are mediated by the Ruderman-Kittel-Kasuya-Yosida mechanism through the electron gas. Recent work predicts that such a system may intrinsically support topological superconductivity without spin-orbit coupling when a helical spin-density wave is spontaneously formed in the spins, and superconductivity is induced in the electron gas. We analyze, using both analytical and numerical techniques, the conditions under which such a helical spin state is stable in a realistic situation in the presence of disorder. We show that (i) it appears only when the spins are coupled to a (quasi-) one-dimensional electron gas, and (ii) it becomes unstable towards the formation of (anti)ferromagnetic domains if the disorder in the impurity spin positions δR becomes comparable with the Fermi wavelength. We also examine the stability of the helical state against Gaussian potential disorder in the electronic system using a diagrammatic approach. Our results suggest that in order to stabilize the helical spin state and thus the emergent topological superconductivity under realistic experimental conditions, a sufficiently strong Rashba spin-orbit coupling, giving rise to Dzyaloshinskii-Moriya interactions, is required.

  17. Human γ-Glutamyl Transpeptidase 1: STRUCTURES OF THE FREE ENZYME, INHIBITOR-BOUND TETRAHEDRAL TRANSITION STATES, AND GLUTAMATE-BOUND ENZYME REVEAL NOVEL MOVEMENT WITHIN THE ACTIVE SITE DURING CATALYSIS.

    PubMed

    Terzyan, Simon S; Burgett, Anthony W G; Heroux, Annie; Smith, Clyde A; Mooers, Blaine H M; Hanigan, Marie H

    2015-07-10

    γ-Glutamyl transpeptidase 1 (GGT1) is a cell surface, N-terminal nucleophile hydrolase that cleaves glutathione and other γ-glutamyl compounds. GGT1 expression is essential in cysteine homeostasis, and its induction has been implicated in the pathology of asthma, reperfusion injury, and cancer. In this study, we report four new crystal structures of human GGT1 (hGGT1) that show conformational changes within the active site as the enzyme progresses from the free enzyme to inhibitor-bound tetrahedral transition states and finally to the glutamate-bound structure prior to the release of this final product of the reaction. The structure of the apoenzyme shows flexibility within the active site. The serine-borate-bound hGGT1 crystal structure demonstrates that serine-borate occupies the active site of the enzyme, resulting in an enzyme-inhibitor complex that replicates the enzyme's tetrahedral intermediate/transition state. The structure of GGsTop-bound hGGT1 reveals its interactions with the enzyme and why neutral phosphonate diesters are more potent inhibitors than monoanionic phosphonates. These structures are the first structures for any eukaryotic GGT that include a molecule in the active site covalently bound to the catalytic Thr-381. The glutamate-bound structure shows the conformation of the enzyme prior to release of the final product and reveals novel information regarding the displacement of the main chain atoms that form the oxyanion hole and movement of the lid loop region when the active site is occupied. These data provide new insights into the mechanism of hGGT1-catalyzed reactions and will be invaluable in the development of new classes of hGGT1 inhibitors for therapeutic use. PMID:26013825

  18. Rapidly converging bound state eigenenergies for the two dimensional quantum dipole

    NASA Astrophysics Data System (ADS)

    Handy, C. R.; Vrinceanu, D.

    2013-06-01

    We examine the effectiveness of a new spectral method in solving the two dimensional dipole problem (DP), as originally formulated by Dasbiswas et al (2010 Phys. Rev. B: At. Mol. Opt. Phys. 81 064516), and recently analysed by Amore and Fernandez (AF, 2012 Phys. Rev. B: At. Mol. Opt. Phys. 45 235004), through a large, non-orthogonal basis, Rayleigh-Ritz (RR) analysis. This deceptively simple problem has a long history of poorly approximated energy values, particularly for the ground state, until the recent work by AF. In contrast to their approach, we implement an orthogonal polynomial projection quantization (OPPQ) analysis (Handy and Vrinceanu 2013 J. Phys. A: Math. Theor. 46 135202), involving expanding the wavefunction in terms of a complete basis, \\Psi ({\\overrightarrow{r}}) = \\sum _n \\Omega _n P_n( {\\overrightarrow{r}}) R({\\overrightarrow{r}}), where P_n are the orthogonal polynomials relative to the weight R. For systems transformable into a moment equation, such as DP, the projection coefficients are determinable in closed form, yielding an efficient quantization procedure, particularly when the weight assumes the asymptotic form of the physical solutions. There are several theoretical reasons why the OPPQ should be more effective than the above RR approach. Indeed, comparable results are achieved with significantly fewer OPPQ variational parameters as compared to RR-variational parameters. For instance, with regards to the delicate ground state energy, 130 OPPQ variables are required to achieve Egr = -0.137 7614 (Egr = -0.137 7514 after a Shanks transform) as opposed to the 821 required within the RR formulation: Egr = -0.137 7478. Despite this, the relative slow convergence for low lying even parity states, within both the OPPQ and RR formulations, suggests that significant logarithmic contributions to the wavefunction, at the origin, have been ignored by all previous investigators. Modifying the RR variational analysis to include log

  19. Engineering Complex Embedded Systems with State Analysis and the Mission Data System

    NASA Technical Reports Server (NTRS)

    Ingham, Michel D.; Rasmussen, Robert D.; Bennett, Matthew B.; Moncada, Alex C.

    2004-01-01

    It has become clear that spacecraft system complexity is reaching a threshold where customary methods of control are no longer affordable or sufficiently reliable. At the heart of this problem are the conventional approaches to systems and software engineering based on subsystem-level functional decomposition, which fail to scale in the tangled web of interactions typically encountered in complex spacecraft designs. Furthermore, there is a fundamental gap between the requirements on software specified by systems engineers and the implementation of these requirements by software engineers. Software engineers must perform the translation of requirements into software code, hoping to accurately capture the systems engineer's understanding of the system behavior, which is not always explicitly specified. This gap opens up the possibility for misinterpretation of the systems engineer s intent, potentially leading to software errors. This problem is addressed by a systems engineering methodology called State Analysis, which provides a process for capturing system and software requirements in the form of explicit models. This paper describes how requirements for complex aerospace systems can be developed using State Analysis and how these requirements inform the design of the system software, using representative spacecraft examples.

  20. An internal ligand-bound, metastable state of a leukocyte integrin, αXβ2

    PubMed Central

    Sen, Mehmet; Yuki, Koichi

    2013-01-01

    How is massive conformational change in integrins achieved on a rapid timescale? We report crystal structures of a metastable, putative transition state of integrin αXβ2. The αXβ2 ectodomain is bent; however, a lattice contact stabilizes its ligand-binding αI domain in a high affinity, open conformation. Much of the αI α7 helix unwinds, loses contact with the αI domain, and reshapes to form an internal ligand that binds to the interface between the β propeller and βI domains. Lift-off of the αI domain above this platform enables a range of extensional and rotational motions without precedent in allosteric machines. Movements of secondary structure elements in the β2 βI domain occur in an order different than in β3 integrins, showing that integrin β subunits can be specialized to assume different intermediate states between closed and open. Mutations demonstrate that the structure trapped here is metastable and can enable rapid equilibration between bent and extended-open integrin conformations and up-regulation of leukocyte adhesiveness. PMID:24385486

  21. An internal ligand-bound, metastable state of a leukocyte integrin, αXβ2.

    PubMed

    Sen, Mehmet; Yuki, Koichi; Springer, Timothy A

    2013-11-25

    How is massive conformational change in integrins achieved on a rapid timescale? We report crystal structures of a metastable, putative transition state of integrin αXβ2. The αXβ2 ectodomain is bent; however, a lattice contact stabilizes its ligand-binding αI domain in a high affinity, open conformation. Much of the αI α7 helix unwinds, loses contact with the αI domain, and reshapes to form an internal ligand that binds to the interface between the β propeller and βI domains. Lift-off of the αI domain above this platform enables a range of extensional and rotational motions without precedent in allosteric machines. Movements of secondary structure elements in the β2 βI domain occur in an order different than in β3 integrins, showing that integrin β subunits can be specialized to assume different intermediate states between closed and open. Mutations demonstrate that the structure trapped here is metastable and can enable rapid equilibration between bent and extended-open integrin conformations and up-regulation of leukocyte adhesiveness. PMID:24385486

  1. Bound states in one-dimensional acoustic parity-time-symmetric lattices for perfect sensing

    NASA Astrophysics Data System (ADS)

    Zhao, Degang; Shen, Yaxi; Zhang, Yu; Zhu, Xuefeng; Yi, Lin

    2016-08-01

    In this letter, we study the propagation of acoustic waves through a one-dimensional multilayer structure composed of a thin defect layer sandwiched by two phononic crystals. Two kinds of defect states will generate in band gaps and both of them cause unitary transmission. However, they have very unlike field distributions due to the different contrasted acoustic impedances between the defect layer and its neighboring layers. Spectral positions of transmission peaks can be exactly determined by the resonant phase condition. In a non-dissipative system, these resonant states correspond to single crossing point of two eigenvalues of scattering matrix. When gain and loss are introduced to judiciously construct an acoustic parity-time-symmetric lattice, the crossing point will split into a pair of exceptional points (EPs). Interestingly, the EPs correspond to unidirectional zero reflection that is very sensitive to the thickness of defect layer. Taking advantage of this virtue, a very sensitive acoustic sensor can be designed, which has potentially applications in ultrasonic inspection, noise detection, ultrasonic medicine, etc.

  2. Ionization of barium through a coherent excitation of two bound intermediate states

    NASA Astrophysics Data System (ADS)

    Luc-Koenig, E.; Aymar, M.; Millet, M.; Lecomte, J.-M.; Lyras, A.

    We have investigated theoretically the asymmetrical photoionization yields into the 6s1/2, 5d3/2 and 5d5/2 continuum channels of atomic barium observed by Wang, Chen and Elliott [Phys. Rev. Lett. 77, 2416 (1996)] in the study of coherent control through two-color resonant interfering paths. The atomic parameters obtained from a theoretical approach based on a combination of jj-coupled eigenchannel R-matrix and Multichannel Quantum Defect Theory are used to analyze the photoionization spectra from the and 6s7p states with polarized light beams. The studied energy range includes the 6p7p autoionizing resonances. The dynamics of the two-color photoionization is governed by the coherent excitation of the 6s6p and intermediate states. This excitation is described as an adiabatic process in the rotating wave approximation. The influence of the radiative decay, spatial distribution of the intensities of the laser beams and hyperfine interaction is discussed.

  3. 85.7 MHz repetition rate mode-locked semiconductor disk laser: fundamental and soliton bound states.

    PubMed

    Butkus, M; Viktorov, E A; Erneux, T; Hamilton, C J; Maker, G; Malcolm, G P A; Rafailov, E U

    2013-10-21

    Mode-locked optically pumped semiconductor disk lasers (SDLs) are in strong demand for applications in bio-medical photonics, chemistry, space communications and non-linear optics. However, the wider spread of SDLs was constrained as they are operated in high repetition rates above 200 MHz due to short carrier lifetimes in the semiconductors. Here we demonstrate experimentally and theoretically that it is possible to overcome the limitation of fast carrier relaxation and show significant reduction of repetition rate down to 85.7 MHz by exploiting phase-amplitude coupling effect. In addition, a low repetition rate SDL serves as a test-bed for bound soliton state previously unknown for semiconductor devices. The breakthrough to sub-100 MHz repetition rate will open a whole new window of development opportunities. PMID:24150392

  4. Absence of Andreev bound states in β -PdBi2 probed by point-contact Andreev reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Che, Liqiang; Le, Tian; Xu, C. Q.; Xing, X. Z.; Shi, Zhixiang; Xu, Xiaofeng; Lu, Xin

    2016-07-01

    We report point-contact spectroscopic studies on high quality single crystalline β -PdBi2 with a superconducting Tc=5.2 K . Our measurements show a typical double-peak structure in the voltage-biased junction conductance at low temperatures, probably excluding the existence of topological Andreev bound states. The conductance curves can be well fitted with the standard Blonder-Tinkham-Klapwijk model for s -wave superconductors, yielding a superconducting gap Δ0≃0.92 meV with 2 Δ0/kBTc˜4.1 . Our results strongly suggest that β -PdBi2 is a conventional intermediate-coupling s -wave superconductor.

  5. Spin polarized bound states in the continuum in open Aharonov–Bohm rings with the Rashba spin–orbit interaction

    NASA Astrophysics Data System (ADS)

    Bulgakov, Evgeny N.; Sadreev, Almas F.

    2016-07-01

    We consider the trapping of electrons with a definite spin polarization by bound states in the continuum (BSC) in the open Aharonov–Bohm rings in the presence of the Rashba spin–orbit interaction (RSOI). Neglecting the Zeeman term we show the existence of BSCs in the one-dimensional ring when the eigenstates of the closed ring are doubly degenerate. With account of the Zeeman term BSCs occur only at the points of threefold degeneracy. The BSCs are found in the parametric space of flux and RSOI strength in close pairs with opposite spin polarization. Thereby the spin polarization of electrons transmitted through the ring can be altered by minor variation of magnetic or electric field at the vicinity of these pairs. Numerical simulations of the two-dimensional open ring show similar results for the BSCs. Encircling the BSC points in the parametric space of the flux and the RSOI constant gives rise to a geometric phase.

  6. Fano effect in the Andreev reflection of the Aharonov-Bohm-Fano ring with Majorana bound states

    NASA Astrophysics Data System (ADS)

    Jiang, Cui; Zheng, Yi-Song

    2015-06-01

    The Andreev reflection in an Aharonov-Bohm-Fano ring induced by Majorana bound states (MBSs) is theoretically investigated. We find that compared with the Fano effect in the normal electron tunneling process, the Fano effect here is more determined by the structural parameters, i.e., the quantum dot level, the dot-MBS coupling, and the dot-MBS and MBS-lead couplings. By transforming the ring into its Nambu representation, we present a comprehensive analysis about the quantum interference in the Andreev reflection, and then explain the reason for the occurrence of the Fano effect. These results will be helpful for understanding the quantum interference in the MBS-assisted Andreev reflection.

  7. Spin polarized bound states in the continuum in open Aharonov-Bohm rings with the Rashba spin-orbit interaction.

    PubMed

    Bulgakov, Evgeny N; Sadreev, Almas F

    2016-07-01

    We consider the trapping of electrons with a definite spin polarization by bound states in the continuum (BSC) in the open Aharonov-Bohm rings in the presence of the Rashba spin-orbit interaction (RSOI). Neglecting the Zeeman term we show the existence of BSCs in the one-dimensional ring when the eigenstates of the closed ring are doubly degenerate. With account of the Zeeman term BSCs occur only at the points of threefold degeneracy. The BSCs are found in the parametric space of flux and RSOI strength in close pairs with opposite spin polarization. Thereby the spin polarization of electrons transmitted through the ring can be altered by minor variation of magnetic or electric field at the vicinity of these pairs. Numerical simulations of the two-dimensional open ring show similar results for the BSCs. Encircling the BSC points in the parametric space of the flux and the RSOI constant gives rise to a geometric phase. PMID:27165662

  8. Using bound exciton transitions to optically resolve neutral donor hyperfine states of various donor species in Silicon-28

    NASA Astrophysics Data System (ADS)

    Salvail, Jeff; Dluhy, Phillip; Saeedi, Kamyar; Szech, Michael; Riemann, Helge; Abromisov, Nikolai; Becker, Peter; Pohl, Hans-Joachim; Thewalt, Michael

    2014-03-01

    Phosphorus in silicon is established as a promising resource for use in quantum information processing tasks. The neutral donor hyperfine states have been shown to have record long coherence times, high fidelity gates via RF pulses, and projective readout via optical bound exciton transitions. As Shannon's theory of information tells us, we can process more information in an alphabet of more symbols, so there is motivation to look at donors with higher nuclear spin than the I = 1 / 2 of 31P, which provide access to Hilbert spaces of dimension greater than two. In this talk I will describe optical studies of the donors 75As (I = 3 / 2), 121Sb (I = 5 / 2), and 209Bi (I = 9 / 2) in 28Si.

  9. Crystal structure of a Na+-bound Na+,K+-ATPase preceding the E1P state.

    PubMed

    Kanai, Ryuta; Ogawa, Haruo; Vilsen, Bente; Cornelius, Flemming; Toyoshima, Chikashi

    2013-10-10

    Na(+),K(+)-ATPase pumps three Na(+) ions out of cells in exchange for two K(+) taken up from the extracellular medium per ATP molecule hydrolysed, thereby establishing Na(+) and K(+) gradients across the membrane in all animal cells. These ion gradients are used in many fundamental processes, notably excitation of nerve cells. Here we describe 2.8 Å-resolution crystal structures of this ATPase from pig kidney with bound Na(+), ADP and aluminium fluoride, a stable phosphate analogue, with and without oligomycin that promotes Na(+) occlusion. These crystal structures represent a transition state preceding the phosphorylated intermediate (E1P) in which three Na(+) ions are occluded. Details of the Na(+)-binding sites show how this ATPase functions as a Na(+)-specific pump, rejecting K(+) and Ca(2+), even though its affinity for Na(+) is low (millimolar dissociation constant). A mechanism for sequential, cooperative Na(+) binding can now be formulated in atomic detail. PMID:24089211

  10. Observability of surface Andreev bound states in a topological insulator in proximity to an s-wave superconductor.

    PubMed

    Snelder, M; Golubov, A A; Asano, Y; Brinkman, A

    2015-08-12

    To guide experimental work on the search for Majorana zero-energy modes, we calculate the superconducting pairing symmetry of a three-dimensional topological insulator in combination with an s-wave superconductor. We show how the pairing symmetry changes across different topological regimes. We demonstrate that a dominant p-wave pairing relation is not sufficient to realise a Majorana zero-energy mode useful for quantum computation. Our main result is the relation between odd-frequency pairing and Majorana zero energy modes by using Green functions techniques in three-dimensional topological insulators in the so-called Majorana regime. We discuss thereafter how the pairing relations in the different regimes can be observed in the tunneling conductance of an s-wave proximised three-dimensional topological insulator. We discuss the necessity to incorporate a ferromagnetic insulator to localise the zero-energy bound state to the interface as a Majorana mode. PMID:26189576

  11. Reexamining surface-integral formulations for one-nucleon transfers to bound and resonance states

    NASA Astrophysics Data System (ADS)

    Escher, J. E.; Thompson, I. J.; Arbanas, G.; Elster, Ch.; Eremenko, V.; Hlophe, L.; Nunes, F. M.; Torus Collaboration

    2014-05-01

    One-nucleon transfer reactions, in particular (d ,p) reactions, have played a central role in nuclear structure studies for many decades. Present theoretical descriptions of the underlying reaction mechanisms are insufficient for addressing the challenges and opportunities that are opening up with new radioactive beam facilities. We investigate a theoretical approach that was proposed recently to address shortcomings in the description of transfers to resonance states. The method builds on ideas from the very successful R-matrix theory; in particular, it uses a similar separation of the coordinate space into interior and exterior regions and introduces a parametrization that can be related to physical observables, which, in principle, makes it possible to extract meaningful spectroscopic information from experiments. We carry out calculations, for a selection of isotopes and energies, to test the usefulness of the new approach.

  12. Non-adiabatic and intersystem crossing dynamics in SO2. II. The role of triplet states in the bound state dynamics studied by surface-hopping simulations

    NASA Astrophysics Data System (ADS)

    Mai, Sebastian; Marquetand, Philipp; González, Leticia

    2014-05-01

    The importance of triplet states in the photorelaxation dynamics of SO2 is studied by mixed quantum-classical dynamics simulations. Using the SHARC method, standing for Surface Hopping including ARbitrary Couplings, intersystem crossing (ISC) processes caused by spin-orbit coupling are found occurring on an ultrafast time scale (few 100 fs) and thus competing with internal conversion. While in the singlet-only dynamics only oscillatory population transfer between the 1B1 and 1A2 states is observed, in the dynamics including singlet and triplet states we find additionally continuous ISC to the 3B2 state and to a smaller extent to the 3B1/3A2 coupled states. The populations obtained from the dynamics are discussed with respect to the overall nuclear motion and in the light of recent TRPEPICO studies [I. Wilkinson, A. E. Boguslavskiy, J. Mikosch, D. M. Villeneuve, H.-J. Wörner, M. Spanner, S. Patchkovskii, and A. Stolow, "Excited state dynamics in SO2. I. Bound state relaxation studied by time-resolved photoelectron-photoion coincidence spectroscopy," J. Chem. Phys. 140, 204301 (2014)].

  13. Gauge invariant description of heavy quark bound states in quantum chromodynamics

    SciTech Connect

    Moore, S.E.

    1980-08-01

    A model for a heavy quark meson is proposed in the framework of a gauge-invariant version of quantum chromodynamics. The field operators in this formulation are taken to be Wilson loops and strings with quark-antiquark ends. The fundamental differential equations of point-like Q.C.D. are expressed as variational equations of the extended loops and strings. The 1/N expansion is described, and it is assumed that nonleading effects such as intermediate quark pairs and nonplanar gluonic terms can be neglected. The action of the Hamiltonian in the A/sub 0/ = 0 gauge on a string operator is derived. A trial meson wave functional is constructed consisting of a path-averaged string operator applied to the full vacuum. A Gaussian in the derivative of the path location is assumed for the minimal form of the measure over paths. A variational parameter is incorporated in the measure as the exponentiated coefficient of the squared path location. The expectation value of the Hamiltonian in the trial state is evaluated for the assumption that the negative logarithm of the expectation value of a Wilson loop is proportional to the loop area. The energy is then minimized by deriving the equivalent quantum mechanical Schroedinger's equation and using the quantum mechanical 1/n expansion to estimate the effective eigenvalues. It is found that the area law behavior of the Wilson loop implies a nonzero best value of the variational parameter corresponding to a quantum broadening of the flux tube.

  14. Fano effect and Andreev bound states in a hybrid superconductor-ferromagnetic nanostructure

    NASA Astrophysics Data System (ADS)

    Siqueira, E. C.; Orellana, P. A.; Cestari, R. C.; Figueira, M. S.; Cabrera, G. G.

    2015-10-01

    In this work, it is considered a hybrid nanostructure composed by a quantum dot coupled to two ferromagnetic leads and a superconductor lead. It is shown that the zero-bias transmittance for the co-tunneling between the ferromagnetic leads presents Fano anti-resonances due to the destructive interference between the two spin channels mixing by the relative orientation of the magnetizations in the leads. When the superconductor is coupled to the system, electron-hole correlations between different spin states lead to a resonance in the place of the dip appearing in the transmittance. Such an effect is accompanied by two Fano anti-resonances explained by a "leakage" of conduction channels from the co-tunneling to the Andreev transport. In the non-equilibrium regime, correlations within the quantum dot introduce a dependence of the resonance condition on the finite bias applied to the ferromagnetic leads. However, it is still possible to observe signatures of the same interference effect in the electrical current.

  15. SO(4) algebraic approach to the three-body bound state problem in two dimensions

    NASA Astrophysics Data System (ADS)

    Dmitrašinović, V.; Salom, Igor

    2014-08-01

    We use the permutation symmetric hyperspherical three-body variables to cast the non-relativistic three-body Schrödinger equation in two dimensions into a set of (possibly decoupled) differential equations that define an eigenvalue problem for the hyper-radial wave function depending on an SO(4) hyper-angular matrix element. We express this hyper-angular matrix element in terms of SO(3) group Clebsch-Gordan coefficients and use the latter's properties to derive selection rules for potentials with different dynamical/permutation symmetries. Three-body potentials acting on three identical particles may have different dynamical symmetries, in order of increasing symmetry, as follows: (1) S3 ⊗ OL(2), the permutation times rotational symmetry, that holds in sums of pairwise potentials, (2) O(2) ⊗ OL(2), the so-called "kinematic rotations" or "democracy symmetry" times rotational symmetry, that holds in area-dependent potentials, and (3) O(4) dynamical hyper-angular symmetry, that holds in hyper-radial three-body potentials. We show how the different residual dynamical symmetries of the non-relativistic three-body Hamiltonian lead to different degeneracies of certain states within O(4) multiplets.

  16. Stable bound states of like charges on top of graphene in magnetic field

    NASA Astrophysics Data System (ADS)

    Slizovskiy, Sergey

    We show theoretically that in the external magnetic field like charges on top of graphene monolayer may be mutually attracted to form thermodinamically stable macro-molecules. For this to happen graphene needs to be in Quantum Hall plateau state with local chemical potential being between the Landau levels. Graphene electron(s) gets localized in the middle between charges and provides overscreening of Coulomb repulsion between the charges. The size of the resulting macro-molecules is of the order of the magnetic length (~ 10 nm for magnetic field 10 T). The possible stable macro-molecules that unit charges can form on graphene in magnetic field are classified. The binding survives significant temperatures, exceeding mobility barriers for many ionically bond impurities. The influence of possible lattice-scale effects of valley-mixing are discussed. Tuning the doping of graphene or the magnetic field, the binding of impurities can be turned on and off and the macro-molecule size may be tuned. This opens the perspective to nanoscopic manipulation of ions on graphene by using magnetic field and gating. Acknowledge EPSRC EP/l02669X/1 and EP/H049797/1 and RSF Grant 14-22-00281.

  17. A matrix lower bound

    SciTech Connect

    Grcar, Joseph F.

    2002-02-04

    A matrix lower bound is defined that generalizes ideas apparently due to S. Banach and J. von Neumann. The matrix lower bound has a natural interpretation in functional analysis, and it satisfies many of the properties that von Neumann stated for it in a restricted case. Applications for the matrix lower bound are demonstrated in several areas. In linear algebra, the matrix lower bound of a full rank matrix equals the distance to the set of rank-deficient matrices. In numerical analysis, the ratio of the matrix norm to the matrix lower bound is a condition number for all consistent systems of linear equations. In optimization theory, the matrix lower bound suggests an identity for a class of min-max problems. In real analysis, a recursive construction that depends on the matrix lower bound shows that the level sets of continuously differential functions lie asymptotically near those of their tangents.

  18. Quadratic Zeeman effect in hydrogen Rydberg states: Rigorous bound-state error estimates in the weak-field regime

    SciTech Connect

    Falsaperla, P.; Fonte, G. Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia 57, I-95129 Catania )

    1993-05-01

    Applying a method based on some results due to Kato [Proc. Phys. Soc. Jpn. 4, 334 (1949)], we show that series of Rydberg eigenvalues and Rydberg eigenfunctions of hydrogen in a uniform magnetic field can be calculated with a rigorous error estimate. The efficiency of the method decreases as the eigenvalue density increases and as [gamma][ital n][sup 3][r arrow]1, where [gamma] is the magnetic-field strength in units of 2.35[times]10[sup 9] G and [ital n] is the principal quantum number of the unperturbed hydrogenic manifold from which the diamagnetic Rydberg states evolve. Fixing [gamma] at the laboratory value 2[times]10[sup [minus]5] and confining our calculations to the region [gamma][ital n][sup 3][lt]1 (weak-field regime), we obtain extremely accurate results up to states corresponding to the [ital n]=32 manifold.

  19. Strong Dependence of Hydration State of F-Actin on the Bound Mg(2+)/Ca(2+) Ions.

    PubMed

    Suzuki, Makoto; Imao, Asato; Mogami, George; Chishima, Ryotaro; Watanabe, Takahiro; Yamaguchi, Takaya; Morimoto, Nobuyuki; Wazawa, Tetsuichi

    2016-07-21

    Understanding of the hydration state is an important issue in the chemomechanical energetics of versatile biological functions of polymerized actin (F-actin). In this study, hydration-state differences of F-actin by the bound divalent cations are revealed through precision microwave dielectric relaxation (DR) spectroscopy. G- and F-actin in Ca- and Mg-containing buffer solutions exhibit dual hydration components comprising restrained water with DR frequency f2 (fw). The hydration state of F-actin is strongly dependent on the ionic composition. In every buffer tested, the HMW signal Dhyme (≡ (f1 - fw)δ1/(fwδw)) of F-actin is stronger than that of G-actin, where δw is DR-amplitude of bulk solvent and δ1 is that of HMW in a fixed-volume ellipsoid containing an F-actin and surrounding water in solution. Dhyme value of F-actin in Ca2.0-buffer (containing 2 mM Ca(2+)) is markedly higher than in Mg2.0-buffer (containing 2 mM Mg(2+)). Moreover, in the presence of 2 mM Mg(2+), the hydration state of F-actin is changed by adding a small fraction of Ca(2+) (∼0.1 mM) and becomes closer to that of the Ca-bound form in Ca2.0-buffer. This is consistent with the results of the partial specific volume and the Cotton effect around 290 nm in the CD spectra, indicating a change in the tertiary structure and less apparent change in the secondary structure of actin. The number of restrained water molecules per actin (N2) is estimated to be 1600-2100 for Ca2.0- and F-buffer and ∼2500 for Mg2.0-buffer at 10-15 °C. These numbers are comparable to those estimated from the available F-actin atomic structures as in the first water layer. The number of HMW molecules is roughly explained by the volume between the equipotential surface of -kT/2e and the first water layer of the actin surface by solving the Poisson-Boltzmann equation using UCSF Chimera. PMID:27332748

  20. College-Bound Seniors, 1979. [College Board ATP Summary Reports for: National, New England, Middle States, Southern, Midwestern, Southwestern, Rocky Mountain, and Western Regions.

    ERIC Educational Resources Information Center

    College Entrance Examination Board, Princeton, NJ.

    The Admissions Testing Program (ATP) is a service of the College Board. The 1979 ATP summary reports on college-bound seniors were produced for each region of the United States, including New England, the Middle, Southern, Midwestern, Southwestern, Rocky Mountain, and Western States. The national and each regional report are in separate booklets.…

  1. State control of discrete-time linear systems to be bound in state variables by equality constraints

    NASA Astrophysics Data System (ADS)

    Filasová, Anna; Krokavec, Dušan; Serbák, Vladimír

    2014-12-01

    The paper is concerned with the problem of designing the discrete-time equivalent PI controller to control the discrete-time linear systems in such a way that the closed-loop state variables satisfy the prescribed equality constraints. Since the problem is generally singular, using standard form of the Lyapunov function and a symmetric positive definite slack matrix, the design conditions are proposed in the form of the enhanced Lyapunov inequality. The results, offering the conditions of the control existence and the optimal performance with respect to the prescribed equality constraints for square discrete-time linear systems, are illustrated with the numerical example to note effectiveness and applicability of the considered approach.

  2. Hyperspherical three-body model calculation for the bound 3,1S-states of Coulombic systems

    NASA Astrophysics Data System (ADS)

    Khan, Md. Abdul

    2015-11-01

    In this paper, hyperspherical three-body model formalism has been applied for the calculation of energies of the low-lying bound 3S-states of neutral helium and helium like Coulombic three-body systems having nuclear charge (z) in the range 2 ≤ Z ≤ 92. Energies of 1S-states are also calculated for those having nuclear charge in the range 14 ≤ Z ≤ 92. The calculation of the coupling potential matrix elements of the two-body potentials has been simplified by the use of Raynal-Revai Coefficients (RRC). The three-body wave function in the Schrödinger equation when expanded in terms of hyperspherical harmonics (HH), leads to an infinite set of coupled differential equation (CDE) which for practical purposes is truncated to a finite set and the truncated set of CDE’s are solved by renormalized Numerov method (RNM) to get the energy (E). The calculated energy is compared with the ones of the literature.

  3. Structural models of intrinsically disordered and calcium-bound folded states of a protein adapted for secretion

    PubMed Central

    O’Brien, Darragh P.; Hernandez, Belen; Durand, Dominique; Hourdel, Véronique; Sotomayor-Pérez, Ana-Cristina; Vachette, Patrice; Ghomi, Mahmoud; Chamot-Rooke, Julia; Ladant, Daniel; Brier, Sébastien; Chenal, Alexandre

    2015-01-01

    Many Gram-negative bacteria use Type I secretion systems, T1SS, to secrete virulence factors that contain calcium-binding Repeat-in-ToXin (RTX) motifs. Here, we present structural models of an RTX protein, RD, in both its intrinsically disordered calcium-free Apo-state and its folded calcium-bound Holo-state. Apo-RD behaves as a disordered polymer chain comprising several statistical elements that exhibit local rigidity with residual secondary structure. Holo-RD is a folded multi-domain protein with an anisometric shape. RTX motifs thus appear remarkably adapted to the structural and mechanistic constraints of the secretion process. In the low calcium environment of the bacterial cytosol, Apo-RD is an elongated disordered coil appropriately sized for transport through the narrow secretion machinery. The progressive folding of Holo-RD in the extracellular calcium-rich environment as it emerges form the T1SS may then favor its unidirectional export through the secretory channel. This process is relevant for hundreds of bacterial species producing virulent RTX proteins. PMID:26374675

  4. Decay of bound states in the continuum of Majorana fermions induced by vacuum fluctuations: Proposal of qubit technology

    NASA Astrophysics Data System (ADS)

    Ricco, L. S.; Marques, Y.; Dessotti, F. A.; Machado, R. S.; de Souza, M.; Seridonio, A. C.

    2016-04-01

    We report on a theoretical investigation of the interplay between vacuum fluctuations, Majorana quasiparticles (MQPs), and bound states in the continuum (BICs) by proposing a new venue for qubit storage. BICs emerge due to quantum interference processes as the Fano effect and, since such a mechanism is unbalanced, these states decay as regular into the continuum. Such fingerprints identify BICs in graphene as we have discussed in detail in Phys. Rev. B 92, 245107 (2015), 10.1103/PhysRevB.92.245107 and Phys. Rev. B, 92, 045409 (2015), 10.1103/PhysRevB.92.045409. Here, by considering two semi-infinite Kitaev chains within the topological phase, coupled to a quantum dot (QD) hybridized with leads, we show the emergence of a novel type of BICs, in which MQPs are trapped. As the MQPs of these chains far apart build a delocalized fermion and qubit, we identify that the decay of these BICs is not connected to Fano and it occurs when finite fluctuations are observed in the vacuum composed by electron pairs for this qubit. From the experimental point of view, we also show that vacuum fluctuations can be induced just by changing the chain-dot couplings from symmetric to asymmetric. Hence, we show how to perform the qubit storage within two delocalized BICs of MQPs and to access it when the vacuum fluctuates by means of a complete controllable way in quantum transport experiments.

  5. Solving Faddeev equations for a bound state and a continuous spectrum of a three-nucleon system by the method of K-harmonic expansions

    SciTech Connect

    Kovalchuk, V. I.; Kozlovsky, I. V.; Tartakovsky, V. K.

    2011-05-15

    A method for solving Faddeev equations in configuration space for a bound state and a continuous spectrum of the system of three nucleons was developed on the basis of expansions in K harmonics. Coulomb interaction and particle spins were not taken into account in this study. The method in question was used to describe the triton bound state and differential cross sections for neutron-deuteron scattering at subthreshold incident-neutron energies. The Volkov, Malfliet-Tjon, and Eikemeier-Hackenbroich local nucleon-nucleon potentials were employed in the present calculations.

  6. Solution structure of a paradigm ArsR family zinc sensor in the DNA-bound state.

    PubMed

    Arunkumar, Alphonse I; Campanello, Gregory C; Giedroc, David P

    2009-10-27

    Staphylococcus aureus CzrA is a zinc-dependent transcriptional repressor from the ubiquitous ArsR family of metal sensor proteins. Zn(II) binds to a pair of intersubunit C-terminal alpha5-sensing sites, some 15 A distant from the DNA-binding interface, and allosterically inhibits DNA binding. This regulation is characterized by a large allosteric coupling free energy (DeltaGc) of approximately +6 kcal mol(-1), the molecular origin of which is poorly understood. Here, we report the solution quaternary structure of homodimeric CzrA bound to a palindromic 28-bp czr operator, a structure that provides an opportunity to compare the two allosteric "end" states of an ArsR family sensor. Zn(II) binding drives a quaternary structural switch from a "closed" DNA-binding state to a low affinity "open" conformation as a result of a dramatic change in the relative orientations of the winged helical DNA binding domains within the dimer. Zn(II) binding also effectively quenches both rapid and intermediate timescale internal motions of apo-CzrA while stabilizing the native state ensemble. In contrast, DNA binding significantly enhances protein motions in the allosteric sites and reduces the stability of the alpha5 helices as measured by H-D solvent exchange. This study reveals how changes in the global structure and dynamics drive a long-range allosteric response in a large subfamily of bacterial metal sensor proteins, and provides insights on how other structural classes of ArsR sensor proteins may be regulated by metal binding. PMID:19822742

  7. Data embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.

    1997-08-19

    A method is disclosed for embedding auxiliary information into a set of host data, such as a photograph, television signal, facsimile transmission, or identification card. All such host data contain intrinsic noise, allowing pixels in the host data which are nearly identical and which have values differing by less than the noise value to be manipulated and replaced with auxiliary data. As the embedding method does not change the elemental values of the host data, the auxiliary data do not noticeably affect the appearance or interpretation of the host data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. 19 figs.

  8. Data embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.

    1997-01-01

    A method of embedding auxiliary information into a set of host data, such as a photograph, television signal, facsimile transmission, or identification card. All such host data contain intrinsic noise, allowing pixels in the host data which are nearly identical and which have values differing by less than the noise value to be manipulated and replaced with auxiliary data. As the embedding method does not change the elemental values of the host data, the auxiliary data do not noticeably affect the appearance or interpretation of the host data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user.

  9. Dressed-bound-state molecular strong-field approximation: Application to above-threshold ionization of heteronuclear diatomic molecules

    SciTech Connect

    Hasovic, E.; Busuladzic, M.; Becker, W.; Milosevic, D. B.

    2011-12-15

    The molecular strong-field approximation (MSFA), which includes dressing of the molecular bound state, is introduced and applied to above-threshold ionization of heteronuclear diatomic molecules. Expressions for the laser-induced molecular dipole and polarizability as functions of the laser parameters (intensity and frequency) and molecular parameters [molecular orientation, dipole, and parallel and perpendicular polarizabilities of the highest occupied molecular orbital (HOMO)] are presented. Our previous MSFA theory, which incorporates the rescattering effects, is generalized from homonuclear to heteronuclear diatomic molecules. Angle- and energy-resolved high-order above-threshold ionization spectra of oriented heteronuclear diatomic molecules, exemplified by the carbon monoxide (CO) molecule, exhibit pronounced minima, which can be related to the shape of their HOMO-electron-density distribution. For the CO molecule we have found an analytical condition for the positions of these minima. We have also shown that the effect of the dressing of the HOMO is twofold: (i) the laser-induced Stark shift decreases the ionization yield and (ii) the laser-induced time-dependent dipole and polarizability change the oscillatory structure of the spectra.

  10. Comparisons of predicted steady-state levels in rooms with extended- and local-reaction bounding surfaces

    NASA Astrophysics Data System (ADS)

    Hodgson, Murray; Wareing, Andrew

    2008-01-01

    A combined beam-tracing and transfer-matrix model for predicting steady-state sound-pressure levels in rooms with multilayer bounding surfaces was used to compare the effect of extended- and local-reaction surfaces, and the accuracy of the local-reaction approximation. Three rooms—an office, a corridor and a workshop—with one or more multilayer test surfaces were considered. The test surfaces were a single-glass panel, a double-drywall panel, a carpeted floor, a suspended-acoustical ceiling, a double-steel panel, and glass fibre on a hard backing. Each test surface was modeled as of extended or of local reaction. Sound-pressure levels were predicted and compared to determine the significance of the surface-reaction assumption. The main conclusions were that the difference between modeling a room surface as of extended or of local reaction is not significant when the surface is a single plate or a single layer of material (solid or porous) with a hard backing. The difference is significant when the surface consists of multilayers of solid or porous material and includes a layer of fluid with a large thickness relative to the other layers. The results are partially explained by considering the surface-reflection coefficients at the first-reflection angles.

  11. Odd-even effect of transport through a chain of Majorana bound states in a T-shaped junction

    NASA Astrophysics Data System (ADS)

    Gong, W. J.; Wu, B. H.; Zhang, S. F.; Zheng, Y. S.

    2014-05-01

    We investigate the transport characteristics of a chain of Majorana bound states (MBSs) in a T-shaped junction, where two normal leads are coupled to the same terminate MBS. We find the apparent odd-even effect in the transport process. Namely, when the MBS number is odd, the conductance spectrum exhibits a peak in the zero-bias limit. Besides, the shot noise Fano factor in the zero-bias limit (F_0) and the conductance maximum (G_{\\textit{max}}) are related by equation F_0=1-{1\\over2}T_{\\textit{max}} with G={e^2\\over h}T . Otherwise, in the case of even-numbered MBSs, at the zero-bias limit, the conductance encounters its zero value, and the relation between F0 and G_{\\textit{max}} changes as F_0=1+{1\\over2}T_{\\textit{max}} . Further investigation shows that these two kinds of relations are caused by the different interplay mechanisms between the crossed Andreev reflection and the local Andreev reflection. In addition, it is observed that the fluctuation of the inter-MBS couplings contributes little to the transport results. We ascertain that these results are helpful for understanding the MBS signature in transport spectra.

  12. Resonant Andreev reflection in a normal-metal/quantum-dot/superconductor system with coupled Majorana bound states

    NASA Astrophysics Data System (ADS)

    Su-Xin, Wang; Yu-Xian, Li; Jian-Jun, Liu

    2016-03-01

    Andreev reflection (AR) in a normal-metal/quantum-dot/superconductor (N-QD-S) system with coupled Majorana bound states (MBSs) is investigated theoretically. We find that in the N-QD-S system, the AR can be enhanced when coupling to the MBSs is incorporated. Fano line-shapes can be observed in the AR conductance spectrum when there is an appropriate QD-MBS coupling or MBS-MBS coupling. The AR conductance is always e2/2h at the zero Fermi energy point when only QD-MBSs coupling is considered. In addition, the resonant AR occurs when the MBS-MBS coupling roughly equals to the QD energy level. We also find that an AR antiresonance appears when the QD energy level approximately equals to the sum of the QD-MBS coupling and the MBS-MBS coupling. These features may serve as characteristic signatures for the probe of MBSs. Project supported by the National Natural Science Foundation of China (Grant Nos. 61176089 and 10974043), the Natural Science Foundation of Hebei Province, China (Grant Nos. A2011205092 and 2014205005), and the Fund for Hebei Normal University for Nationalities, China (Grant No. 201109).

  13. Population of isomeric states in fusion and transfer reactions in beams of loosely bound nuclei near the Coulomb barrier

    SciTech Connect

    Skobelev, N. K.

    2015-07-15

    The influence of the mechanisms of nuclear reactions on the population of {sup 195m}Hg and {sup 197m}Hg(7/2{sup −}), {sup 198m}Tl and {sup 196m}Tl(7{sup +}), and {sup 196m}Au and {sub 198m}Au(12{sup −}) isomeric nuclear states obtained in reactions induced by beams of {sup 3}He, {sup 6}Li, and {sup 6}He weakly bound nuclei is studied. The behavior of excitation functions and high values of isomeric ratios (δ{sub m}/δ{sub g}) for products of nuclear reactions proceeding through a compound nucleus and involving neutron evaporation are explained within statistical models. Reactions in which the emission of charged particles occurs have various isomeric ratios depending on the reaction type. The isomeric ratio is lower in direct transfer reactions involving charged-particle emission than in reactions where the evaporation of charged particles occurs. Reactions accompanied by neutron transfer usually have a lower isomeric ratio, which behaves differently for different direct-reaction types (stripping versus pickup reactions)

  14. Joint experimental-theoretical investigation of the lower bound states of the NO(X2Pi)-Kr complex.

    PubMed

    Wen, Bo; Meyer, Henning; Kłos, Jacek; Alexander, Millard H

    2009-07-01

    We describe the first measurement of the near IR spectrum of the NO-Kr van der Waals complex. A variant of IR-REMPI double-resonance spectroscopy is employed in which the IR and UV lasers are scanned simultaneously in such a way that throughout the scan the sum of the two photon energies is kept constant, matching a UV resonance of the system. In the region of the first overtone vibration of the NO monomer, we observe several rotationally resolved bands for the NO-Kr complex. In addition to the origin band located at 3723.046 cm(-1), we observe excited as well as hot bands involving the excitation of one or two quanta of z-axis rotation. Another band is assigned to the excitation of one quantum of bending vibration. The experimental spectra are compared with results of bound-state calculations for a new set of potential energy surfaces calculated at the spin-restricted coupled cluster level. For the average vibration-rotation energies, there is excellent agreement between the theoretical results based on the coupled states (CS) approximation and the full close-coupling (CC) treatment. Finer details like the electrostatic splitting and the P-type doubling of the rotational levels are accounted for only within the CC formalism. The comparison of the CC results with the measured spectra confirms the high quality of the PESs. However, the high resolution of the experiments is sufficient to identify some inaccuracies in the difference between the potential energy surfaces of A' and A'' reflection symmetry. PMID:19388642

  15. Message Embedded Chaotic Masking Synchronization Scheme Based on the Generalized Lorenz System and Its Security Analysis

    NASA Astrophysics Data System (ADS)

    Čelikovský, Sergej; Lynnyk, Volodymyr

    This paper focuses on the design of the novel chaotic masking scheme via message embedded synchronization. A general class of the systems allowing the message embedded synchronization is presented here, moreover, it is shown that the generalized Lorenz system belongs to this class. Furthermore, the secure encryption scheme based on the message embedded synchronization is proposed. This scheme injects the embedded message into the dynamics of the transmitter as well, ensuring thereby synchronization with theoretically zero synchronization error. To ensure the security, the embedded message is a sum of the message and arbitrary bounded function of the internal transmitter states that is independent of the scalar synchronization signal. The hexadecimal alphabet will be used to form a ciphertext making chaotic dynamics of the transmitter even more complicated in comparison with the transmitter influenced just by the binary step-like function. All mentioned results and their security are tested and demonstrated by numerical experiments.

  16. High Field Solid-State NMR Spectroscopy Investigation of (15)N-Labeled Rosette Nanotubes: Hydrogen Bond Network and Channel-Bound Water.

    PubMed

    Fenniri, Hicham; Tikhomirov, Grigory A; Brouwer, Darren H; Bouatra, Souhaila; El Bakkari, Mounir; Yan, Zhimin; Cho, Jae-Young; Yamazaki, Takeshi

    2016-05-18

    (15)N-labeled rosette nanotubes were synthesized and investigated using high-field solid-state NMR spectroscopy, X-ray diffraction, atomic force microscopy, and electron microscopy. The results established the H-bond network involved in the self-assembly of the nanostructure as well as bound water molecules in the nanotube's channel. PMID:27141817

  17. Instability-related delamination growth of embedded and edge delaminations. Ph.D. Thesis - Virginia Polytechnic Inst. and State Univ.

    NASA Technical Reports Server (NTRS)

    Whitcomb, John D.

    1988-01-01

    Compressive loads can cause local buckling in composite laminates that have a near surface delamination. This buckling causes load redistribution and secondary loads, which in turn cause interlaminar stresses and delamination growth. The goal of this research was to enhance the understanding of this instability-related delamination growth in laminates containing either an embedded or an edge delamination.

  18. Sets of states and extreme points

    SciTech Connect

    Keller, K.

    1989-01-01

    The natural embedding of orthoposets and quantum logics, equipped with certain sets of states, into their corresponding order-unit normed vector space is investigated. Necessary (resp, sufficient) conditions are stated for the case that the image of the embedding and the extreme points of the order interval, bounded by 0 and the order unit, coincide. Modifications of the state space are discussed from this point of view and the special case of a Boolean algebra is characterized.

  19. Bounding Species Distribution Models

    NASA Technical Reports Server (NTRS)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  20. Bounding species distribution models

    USGS Publications Warehouse

    Stohlgren, T.J.; Jarnevich, C.S.; Esaias, W.E.; Morisette, J.T.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used. ?? 2011 Current Zoology.

  1. Causality and Tsirelson's bounds

    SciTech Connect

    Buhrman, H.; Massar, S.

    2005-11-15

    We study the properties of no-signaling correlations that cannot be reproduced by local measurements on entangled quantum states. We say that such correlations violate Tsirelson bounds. We show that if these correlations are obtained by some reversible unitary quantum evolution U, then U cannot be written in the product form U{sub A}xU{sub B}. This implies that U can be used for signaling and for entanglement generation. This result is completely general and in fact can be viewed as a characterization of Tsirelson bounds. We then show how this result can be used as a tool to study Tsirelson bounds and we illustrate this by rederiving the Tsirelson bound of 2{radical}(2) for the Clauser-Horn-Shimony-Holt inequality, and by deriving a new Tsirelson bound for qutrits.

  2. Sufficient Conditions for Global Minimality of Metastable States in a Class of Non-convex Functionals: A Simple Approach Via Quadratic Lower Bounds

    NASA Astrophysics Data System (ADS)

    Shirokoff, David; Choksi, Rustum; Nave, Jean-Christophe

    2015-06-01

    We consider mass-constrained minimizers for a class of non-convex energy functionals involving a double-well potential. Based upon global quadratic lower bounds to the energy, we introduce a simple strategy to find sufficient conditions on a given critical point (metastable state) to be a global minimizer. We show that this strategy works well for the one exact and known metastable state: the constant state. In doing so, we numerically derive an almost optimal lower bound for both the order-disorder transition curve of the Ohta-Kawasaki energy and the liquid-solid interface of the phase-field crystal energy. We discuss how this strategy extends to non-constant computed metastable states, and the resulting symmetry issues that one must overcome. We give a preliminary analysis of these symmetry issues by addressing the global optimality of a computed lamellar structure for the Ohta-Kawasaki energy in one (1D) and two (2D) space dimensions. We also consider global optimality of a non-constant state for a spatially in-homogenous perturbation of the 2D Ohta-Kawasaki energy. Finally we use one of our simple quadratic lower bounds to rigorously prove that for certain values of the Ohta-Kawasaki parameter and aspect ratio of an asymmetric torus, any global minimizer for the 1D problem is automatically a global minimizer for the 2D problem on the asymmetric torus.

  3. Spermatozoa bound to solid state hyaluronic acid show chromatin structure with high DNA chain integrity: an acridine orange fluorescence study.

    PubMed

    Yagci, Artay; Murk, William; Stronk, Jill; Huszar, Gabor

    2010-01-01

    During human spermiogenesis, the elongated spermatids undergo a plasma membrane remodeling step that facilitates formation of the zona pellucida and hyaluronic acid (HA) binding sites. Various biochemical sperm markers indicated that human sperm bound to HA exhibit attributes similar to that of zona pellucida-bound sperm, including minimal DNA fragmentation, normal shape, and low frequency of chromosomal aneuploidies. In this work, we tested the hypothesis that HA-bound sperm would be enhanced in sperm of high DNA chain integrity and green acridine orange fluorescence (AOF) compared with the original sperm in semen. Sperm DNA integrity in semen and in their respective HA-bound sperm fractions was studied in 50 men tested for fertility. In the semen samples, the proportions of sperm with green AOF (high DNA integrity) and red AOF (DNA breaks) were 54.9% ± 2.0% and 45.0% ± 1.9%, whereas in the HA-bound sperm fraction, the respective proportions were 99% and 1.0%, respectively. The data indeed demonstrated that HA shows a high degree of selectivity for sperm with high DNA integrity. These findings are important from the points of view of human sperm DNA integrity, sperm function, and the potential efficacy of HA-mediated sperm selection for intracytoplasmic sperm injection. PMID:20133967

  4. Universal bounds on current fluctuations

    NASA Astrophysics Data System (ADS)

    Pietzonka, Patrick; Barato, Andre C.; Seifert, Udo

    2016-05-01

    For current fluctuations in nonequilibrium steady states of Markovian processes, we derive four different universal bounds valid beyond the Gaussian regime. Different variants of these bounds apply to either the entropy change or any individual current, e.g., the rate of substrate consumption in a chemical reaction or the electron current in an electronic device. The bounds vary with respect to their degree of universality and tightness. A universal parabolic bound on the generating function of an arbitrary current depends solely on the average entropy production. A second, stronger bound requires knowledge both of the thermodynamic forces that drive the system and of the topology of the network of states. These two bounds are conjectures based on extensive numerics. An exponential bound that depends only on the average entropy production and the average number of transitions per time is rigorously proved. This bound has no obvious relation to the parabolic bound but it is typically tighter further away from equilibrium. An asymptotic bound that depends on the specific transition rates and becomes tight for large fluctuations is also derived. This bound allows for the prediction of the asymptotic growth of the generating function. Even though our results are restricted to networks with a finite number of states, we show that the parabolic bound is also valid for three paradigmatic examples of driven diffusive systems for which the generating function can be calculated using the additivity principle. Our bounds provide a general class of constraints for nonequilibrium systems.

  5. Vibrational state-selective autodetachment photoelectron spectroscopy from dipole-bound states of cold 2-hydroxyphenoxide: o - HO(C6H4)O-

    NASA Astrophysics Data System (ADS)

    Huang, Dao-Ling; Liu, Hong-Tao; Ning, Chuan-Gang; Wang, Lai-Sheng

    2015-03-01

    We report a photodetachment and high-resolution photoelectron imaging study of cold 2-hydroxyphenoxide anion, o - HO(C6H4)O-, cooled in a cryogenic ion trap. Photodetachment spectroscopy revealed a dipole-bound state (DBS) of the anion, 25 ± 5 cm-1, below the detachment threshold of 18ߙ784 ± 5 cm-1 (2.3289 ± 0.0006 eV ), i.e., the electron affinity of the 2-hydroxyphenoxy radical o - HO(C6H4)Oṡ. Twenty-two vibrational levels of the DBS are observed as resonances in the photodetachment spectrum. By tuning the detachment laser to these DBS vibrational levels, we obtain 22 high-resolution resonant photoelectron spectra, which are highly non-Franck-Condon due to mode-selective autodetachment and the Δv = - 1 propensity rule. Numerous Franck-Condon inactive vibrational modes are observed in the resonant photoelectron spectra, significantly expanding the vibrational information that is available in traditional high-resolution photoelectron spectroscopy. A total of 15 fundamental vibrational frequencies are obtained for the o - HO(C6H4)Oṡ radical from both the photodetachment spectrum and the resonant photoelectron spectra, including six symmetry-forbidden out-of-plane modes as a result of resonant enhancement.

  6. Quantum transport through a multi-quantum-dot-pair chain side-coupled with Majorana bound states

    NASA Astrophysics Data System (ADS)

    Zhao-Tan, Jiang; Cheng-Cheng, Zhong

    2016-06-01

    We investigate the quantum transport properties through a special kind of quantum dot (QD) system composed of a serially coupled multi-QD-pair (multi-QDP) chain and side-coupled Majorana bound states (MBSs) by using the Green functions method, where the conductance can be classified into two kinds: the electron tunneling (ET) conductance and the Andreev reflection (AR) one. First we find that for the nonzero MBS-QDP coupling a sharp AR-induced zero-bias conductance peak with the height of e 2/h is present (or absent) when the MBS is coupled to the far left (or the other) QDP. Moreover, the MBS-QDP coupling can suppress the ET conductance and strengthen the AR one, and further split into two sub-peaks each of the total conductance peaks of the isolated multi-QDPs, indicating that the MBS will make obvious influences on the competition between the ET and AR processes. Then we find that the tunneling rate Γ L is able to affect the conductances of leads L and R in different ways, demonstrating that there exists a Γ L-related competition between the AR and ET processes. Finally we consider the effect of the inter-MBS coupling on the conductances of the multi-QDP chains and it is shown that the inter-MBS coupling will split the zero-bias conductance peak with the height of e 2/h into two sub-peaks. As the inter-MBS coupling becomes stronger, the two sub-peaks are pushed away from each other and simultaneously become lower, which is opposite to that of the single QDP chain where the two sub-peaks with the height of about e 2/2h become higher. Also, the decay of the conductance sub-peaks with the increase of the MBS-QDP coupling becomes slower as the number of the QDPs becomes larger. This research should be an important extension in studying the transport properties in the kind of QD systems coupled with the side MBSs, which is helpful for understanding the nature of the MBSs, as well as the MBS-related QD transport properties. Project supported by the National Natural

  7. Unified ab initio approach to bound and unbound states: No-core shell model with continuum and its application to 7He

    DOE PAGESBeta

    Baroni, Simone; Navratil, Petr; Quaglioni, Sofia

    2013-03-26

    In this study, we introduce a unified approach to nuclear bound and continuum states based on the coupling of the no-core shell model (NCSM), a bound-state technique, with the no-core shell model/resonating group method (NCSM/RGM), a nuclear scattering technique. This new ab initio method, no-core shell model with continuum (NCSMC), leads to convergence properties superior to either NCSM or NCSM/RGM while providing a balanced approach to different classes of states. In the NCSMC, the ansatz for the many-nucleon wave function includes (i) a square-integrable A-nucleon component expanded in a complete harmonic oscillator basis and (ii) a binary-cluster component with asymptoticmore » boundary conditions that can properly describe weakly bound states, resonances, and scattering. The Schrödinger equation is transformed into a system of coupled-channel integral-differential equations that we solve using a modified microscopic R-matrix formalism within a Lagrange mesh basis. We demonstrate the usefulness of the approach by investigating the unbound 7He nucleus.« less

  8. The Impact of Welfare State Regimes on Barriers to Participation in Adult Education: A Bounded Agency Model

    ERIC Educational Resources Information Center

    Rubenson, Kjell; Desjardins, Richard

    2009-01-01

    Quantitative and qualitative findings on barriers to participation in adult education are reviewed and some of the defining parameters that may explain observed national differences are considered. A theoretical perspective based on bounded agency is put forth to take account of the interaction between structurally and individually based barriers…

  9. Bound states for a Coulomb-type potential induced by the interaction between a moving electric quadrupole moment and a magnetic field

    SciTech Connect

    Bakke, K.

    2014-02-15

    We discuss the arising of bound states solutions of the Schrödinger equation due to the presence of a Coulomb-type potential induced by the interaction between a moving electric quadrupole moment and a magnetic field. Furthermore, we study the influence of the Coulomb-type potential on the harmonic oscillator by showing a quantum effect characterized by the dependence of the angular frequency on the quantum numbers of the system, whose meaning is that not all values of the angular frequency are allowed. -- Highlights: • Interaction between a moving electric quadrupole moment and a magnetic field. • Arising of bound states solutions due to the presence of a Coulomb-type potential. • Influence of the Coulomb-type potential on the harmonic oscillator. • Dependence of the angular frequency on the quantum numbers of the system.

  10. A search for the K-pp bound state in the 3He(K-in-flight, n) reaction at J-PARC

    NASA Astrophysics Data System (ADS)

    Hashimoto, T.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kato, Y.; Kawasaki, S.; Kienle, P.; Kou, H.; Ma, Y.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Poli Lener, M.; Romero Vida, A.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tanida, K.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Vazquez Doce, O.; Widmann, E.; Wuenschek, B. K.; Yamaga, T.; Yamazaki, T.; Yim, H.; Zhang, Q.; Zmeska, J.

    2014-03-01

    We have collected the first physics data of an experimental search for the simplest kaonic nuclear bound state, "K- pp", by the 3He(K- n) reaction at J-PARC. We confirmed that our spectrometer system works as designed and observed clear peak structure composed of the quasi-elastic K-"n" → K-n and the charge-exchange K-"p" → ¯̅K0n reactions in the forward neutron spectrum.

  11. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method.

  12. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-03-10

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique is disclosed. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method. 11 figs.

  13. Treatment of continuum in nuclear reactions involving weakly bound systems. A simple model to test different prescriptions describing the coupling to continuum states

    SciTech Connect

    Dasso, C. H.; Vitturi, A.

    2009-03-04

    We exploit a model describing the break-up of weakly-bound nuclei that can be used as a laboratory for testing different prescriptions that have been advanced in the literature to take into account the near-by presence of continuum states. In the model we follow the evolution of a single particle wave function in one dimension, initially bound by a Woods-Saxon type potential and then perturbed by a time- and position-dependent external field. Proper choices of this potential can simulate the effect of the interaction between reaction partners in a nuclear collision. These processes generate inelastic excitation probabilities that--distributed over the bound and continuum states of the system--lead to either a partial or a total fragmentation of the final wave function. The comparison with the exact calculations shows that standard coupled channel descriptions based on discretization of the continuum can be accurate only when a proper choice is made of the number of discrete states, of the energy mesh and of the energy cutoff. This may imply, even in simplified cases, the use of a rather large (and unpracticable) number of channels. The use of a more restricted number of channels may lead to misleading results.

  14. Rashbon Bound States Associated with a Spherical Spin-Orbit Coupling in an Ultracold Fermi Gas with an s-Wave Interaction

    NASA Astrophysics Data System (ADS)

    Yamaguchi, T.; Inotani, D.; Ohashi, Y.

    2016-05-01

    We investigate the formation of rashbon bound states and strong-coupling effects in an ultracold Fermi gas with a spherical spin-orbit interaction, H_so=λ {\\varvec{p}}\\cdot {σ } (where {σ }=(σ _x,σ _y,σ _z) are Pauli matrices). Extending the strong-coupling theory developed by Nozières and Schmitt-Rink (NSR) to include this spin-orbit coupling, we determine the superfluid phase transition temperature T_c, as functions of the strength of a pairing interaction U_s, as well as the spin-orbit coupling strength λ . Evaluating poles of the NSR particle-particle scattering matrix describing fluctuations in the Cooper channel, we clarify the region where rashbon bound states dominate the superfluid phase transition in the U_s-λ phase diagram. Since the antisymmetric spin-orbit interaction H_so breaks the inversion symmetry of the system, rashbon bound states naturally have not only a spin-singlet and even-parity symmetry, but also a spin-triplet and odd-parity symmetry. Thus, our results would be also useful for the study of this parity-mixing effect in the BCS-BEC crossover regime of a spin-orbit coupled Fermi gas.

  15. Outward Bound.

    ERIC Educational Resources Information Center

    Outward Bound, Inc., Andover, MA.

    The Outward Bound concept was developed in Germany and Great Britain with the saving of human life as the ultimate goal. Courses are designed to help students discover their true physical and mental limits through development of skills including emergency medical aid, firefighting, search and rescue, mountaineering, and sailing. Five Outward Bound…

  16. Crystal Structures of SlyA Protein, a Master Virulence Regulator of Salmonella, in Free and DNA-bound States

    SciTech Connect

    Dolan, Kyle T.; Duguid, Erica M.; He, Chuan

    2011-11-17

    SlyA is a master virulence regulator that controls the transcription of numerous genes in Salmonella enterica. We present here crystal structures of SlyA by itself and bound to a high-affinity DNA operator sequence in the slyA gene. SlyA interacts with DNA through direct recognition of a guanine base by Arg-65, as well as interactions between conserved Arg-86 and the minor groove and a large network of non-base-specific contacts with the sugar phosphate backbone. Our structures, together with an unpublished structure of SlyA bound to the small molecule effector salicylate (Protein Data Bank code 3DEU), reveal that, unlike many other MarR family proteins, SlyA dissociates from DNA without large conformational changes when bound to this effector. We propose that SlyA and other MarR global regulators rely more on indirect readout of DNA sequence to exert control over many genes, in contrast to proteins (such as OhrR) that recognize a single operator.

  17. Bound state solutions of the Klein-Gordon equation with the improved expression of the Manning-Rosen potential energy model

    NASA Astrophysics Data System (ADS)

    Jia, Chun-Sheng; Chen, Tao; He, Su

    2013-03-01

    By employing the improved Greene-Aldrich approximation scheme to deal with the centrifugal term, we solve approximately the Klein-Gordon equation with the improved expression of the Manning-Rosen empirical potential energy model. The bound state energy equation and the unnormalized radial wave functions have been approximately obtained by using the supersymmetric WKB approach and the function analysis method. The relativistic vibrational transition frequencies for the a3Σu+ state of 7Li2 molecule have been computed by using the Manning-Rosen potential model. The relativistic vibrational transition frequencies are in good agreement with the observed data.

  18. Excitations and possible bound states in the S = {1/2} alternating chain compound (VO){sub 2}P{sub 2}O{sub 7}

    SciTech Connect

    Tennant, D.A.; Nagler, S.E.; Sales, B.C.

    1997-07-30

    Magnetic excitations in an array of (VO){sub 2}P{sub 2}O{sub 7} single crystals have been measured using inelastic neutron scattering. Until now, (VO){sub 2}P{sub 2}O{sub 7} has been thought of as a two-leg antiferromagnetic Heisenberg spin ladder with chains running in the a-direction. The present results show unequivocally that (VO){sub 2}P{sub 2}O{sub 7} is best described as an alternating spin-chain directed along the crystallographic b-direction. In addition to the expected magnon with magnetic zone-center energy gap {Delta} = 3.1 meV, a second excitation is observed at an energy just below 2{Delta}. The higher mode may be a triplet two-magnon bound state. Numerical results in support of bound modes are presented.

  19. Evidence of Andreev bound states as a hallmark of the FFLO phase in κ-(BEDT-TTF)2Cu(NCS)2

    NASA Astrophysics Data System (ADS)

    Mayaffre, H.; Krämer, S.; Horvatić, M.; Berthier, C.; Miyagawa, K.; Kanoda, K.; Mitrović, V. F.

    2014-12-01

    Superconductivity is a quantum phenomenon arising, in its simplest form, from the pairing of fermions with opposite spin into a state with zero net momentum. Whether superconductivity can occur in fermionic systems with an unequal number of two species distinguished by spin or flavour presents an important open question in condensed-matter physics or quantum chromodynamics. In condensed matter the imbalance between spin-up and spin-down electrons that form the Cooper pairs is induced by the magnetic field. Such an imbalanced system can lead to exotic superconductivity in which pairs acquire finite momentum. This momentum leads to a spatially inhomogeneous state consisting of periodically alternating `normal' and `superconducting' regions. Here, we establish that the hallmark of this state is the appearance of spatially localized and spin-polarized quasiparticles forming the so-called Andreev bound states (ABS). These are detected through our nuclear magnetic resonance (NMR) measurements.

  20. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%.

  1. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-07-07

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique are disclosed. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%. 21 figs.

  2. Observation of breakup transfer process for the bound states of {sup 16}O populated from {sup 12}C({sup 6}Li,d) reaction at 20 MeV

    SciTech Connect

    Adhikari, S.; Basu, C.; Thompson, I. J.; Sugathan, P.; Jhinghan, A.; Golda, K. S.; Babu, A.; Singh, D.; Ray, S.; Mitra, A. K.

    2012-10-20

    The deuteron angular distribution for the {sup 12}C({sup 6}Li,d){sup 16}O* has been measured at 20 MeV populating bound and unbound states of {sup 16}O. Analysis shows a dominance of breakup induced alpha transfer in comparison to a direct alpha transfer process for the bound states. The effect increases as the excitation energy of {sup 16}O decreases, maximizing at the ground state.

  3. Bone Mineral 31P and Matrix-Bound Water Densities Measured by Solid-State 1H and 31P MRI

    PubMed Central

    Seifert, Alan C.; Li, Cheng; Rajapakse, Chamith S.; Bashoor- Zadeh, Mahdieh; Bhagat, Yusuf A.; Wright, Alexander C.; Zemel, Babette S.; Zavaliangos, Antonios; Wehrli, Felix W.

    2014-01-01

    Bone is a composite material consisting of mineral and hydrated collagen fractions. MRI of bone is challenging due to extremely short transverse relaxation times, but solid-state imaging sequences exist that can acquire the short-lived signal from bone tissue. Previous work to quantify bone density via MRI used powerful experimental scanners. This work seeks to establish the feasibility of MRI-based measurement on clinical scanners of bone mineral and collagen-bound water densities, the latter as a surrogate of matrix density, and to examine the associations of these parameters with porosity and donors’ age. Mineral and matrix-bound water images of reference phantoms and cortical bone from 16 human donors, ages 27-97 years, were acquired by zero-echo-time 31P and 1H MRI on whole body 7T and 3T scanners, respectively. Images were corrected for relaxation and RF inhomogeneity to obtain density maps. Cortical porosity was measured by micro-CT, and apparent mineral density by pQCT. MRI-derived densities were compared to x-ray-based measurements by least-squares regression. Mean bone mineral 31P density was 6.74±1.22 mol/L (corresponding to 1129±204 mg/cc mineral), and mean bound water 1H density was 31.3±4.2 mol/L (corresponding to 28.3±3.7 %v/v). Both 31P and bound water (BW) densities were correlated negatively with porosity (31P: R2 = 0.32, p < 0.005; BW: R2 = 0.63, p < 0.0005) and age (31P: R2 = 0.39, p < 0.05; BW: R2 = 0.70, p < 0.0001), and positively with pQCT density (31P: R2 = 0.46, p < 0.05; BW: R2 = 0.50, p < 0.005). In contrast, the bone mineralization ratio (expressed here as the ratio of 31P density to bound water density), which is proportional to true bone mineralization, was found to be uncorrelated with porosity, age, or pQCT density. This work establishes the feasibility of image-based quantification of bone mineral and bound water densities using clinical hardware. PMID:24846186

  4. Computational Refinement and Validation Protocol for Proteins with Large Variable Regions Applied to Model HIV Env Spike in CD4 and 17b Bound State

    PubMed Central

    Rasheed, Muhibur; Bettadapura, Radhakrishna; Bajaj, Chandrajit

    2015-01-01

    Summary Envelope glycoprotein gp120 of HIV-1 possesses several variable regions whose precise structure has been difficult to establish. We report a new model of gp120, in complex with antibodies CD4 and 17b, complete with its variable regions. The model was produced by a computational protocol which uses cryo-electron microscopy (EM) maps, atomic-resolution structures of the core, and information of binding interactions. Our model has excellent fit with EMD5020 (Liu et al., 2008), is stereochemically and energetically favorable, and has the expected binding interfaces. Comparison of the ternary arrangement of the loops in this model with those bound to PGT122 (Julien et al., 2013a) and PGV04 (Lyumkis et al., 2013) suggested a possible motion of the V1V2 away from the CCR5 binding site and towards CD4. Our study also revealed that the CD4-bound state of the V1V2 loop is not optimal for gp120 bound with several neutralizing antibodies. PMID:26039348

  5. Search for the deeply bound K-pp state from the semi-inclusive forward-neutron spectrum in the in-flight K- reaction on helium-3

    NASA Astrophysics Data System (ADS)

    Hashimoto, T.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kato, Y.; Kawasaki, S.; Kienle, P.; Kou, H.; Ma, Y.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Poli Lener, M.; Romero Vidal, A.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, S.; Suzuki, T.; Tanida, K.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Vazquez Doce, O.; Widmann, E.; Yamaga, T.; Yamazaki, T.; Yim, H.; Zhang, Q.; Zmeskal, J.

    2015-06-01

    An experiment to search for the K-pp bound state was performed via the in-flight {}^3He(K-,n) reaction using 5.3 × 10^9 kaons at 1 GeV/c at the J-PARC hadron experimental facility. In the semi-inclusive neutron missing-mass spectrum at θ n^{lab}=0°, no significant peak was observed in the region corresponding to K-pp binding energy larger than 80 MeV, where a bump structure has been reported in the Λ p final state in different reactions. Assuming the state to be isotropically decaying into Λ p, mass-dependent upper limits on the production cross section were determined to be 30-180, 70-250, and 100-270μb/sr, for the natural widths of 20, 60, and 100 MeV, respectively, at 95% confidence level.

  6. Influence of higher-order dispersion coefficients on near-threshold bound and continuum states: Application to {sup 88}Sr{sub 2}

    SciTech Connect

    Kaiser, Alexander; Mueller, Tim-Oliver; Friedrich, Harald

    2011-12-07

    We give a simple description of quantum states near the dissociation threshold of deep interatomic potentials. The influence of the potential tail is separated from effects due to the interaction at short distances. We present a general formalism which is valid for weakly bound and low-energy continuum states, both for vanishing and non-vanishing angular momentum. Its applicability is demonstrated for the example of the electronic ground state of the strontium dimer {sup 88}Sr{sub 2}. With an appropriate choice of the potential tail that includes higher-order dispersion coefficients, all short-range effects are incorporated via the threshold quantum number v{sub D} and one further parameter accounting for residual short-range effects.

  7. Quasi-bound states and continuum absorption background of polar Al{sub 0.5}Ga{sub 0.5}N/GaN quantum dots

    SciTech Connect

    Elmaghraoui, D. Triki, M.; Jaziri, S.; Leroux, M.; Brault, J.

    2014-07-07

    A theoretical interpretation of the photoluminescence excitation spectra of self-organized polar GaN/(Al,Ga)N quantum dots is presented. A numerical method assuming a realistic shape of the dots and including the built-in electric field effects is developed to calculate their energy structure and hence their optical absorption. The electron and hole spectra show the existence of a set of quasi-bound states that does not originate from the wetting layer and plays a crucial role in the observed absorption spectrum of the GaN/(Al,Ga)N dots. Transitions involving these quasi-bound states and wetting layer states give a sufficient explanation for the observed continuum absorption background. The properties of this absorption band, especially its extension, depend strongly on the dot's size. Our simulation provides a natural explanation of the experimental luminescence excitation spectra of ensembles of dots of different heights. Our theoretical model can be convenient for future optical studies including systems with more complicated potentials.

  8. Search for φ-Meson Nuclear Bound States in the overline{p} + ^{A}Z → φ + ^{A-1}_{φ}(Z-1) Reaction

    NASA Astrophysics Data System (ADS)

    Bühler, P.; Curceanu, C.; Guaraldo, C.; Hartmann, O.; Hicks, K.; Iwasaki, M.; Ishiwatari, T.; Kienle, P.; Marton, J.; Muto, R.; Niiyama, M.; Noumi, H.; Ohnishi, H.; Okada, S.; Vidal, A.; Sakaguchi, A.; Sakuma, F.; Sawada, S.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Tsukada, K.; Tedeschi, D. J.; Doce, O.; Widmann, E.; Yokkaichi, S.; Zmeskal, J.; J-Parc P29 Collaboration

    We propose to study in-medium mass modification of the φ mesonusing the formation of φ meson bound state. We demonstrate that a clear missing-mass spectrum can be obtained efficiently by (overline{p}, φ) spectroscopy together with the Λ tagging, using the primary reaction channel overline{p} p → φ φ. A systematic study over several nuclear targets will yield a unique, definitive and precise determination of the in-medium mass modification of the vector meson φ (s overline{s}).

  9. Search for the K- pp bound state via the 3He(K-, n) reaction at 1 GeV/c

    NASA Astrophysics Data System (ADS)

    Hashimoto, T.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kato, Y.; Kawasaki, S.; Kienle, P.; Kou, H.; Ma, Y.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Poli Lener, M.; Romero Vidal, A.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tanida, K.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Vazquez Doce, O.; Widmann, E.; Wuenschek, B. K.; Yamaga, T.; Yamazaki, T.; Yim, H.; Zhang, Q.; Zmeskal, J.; J-Parc E15 Collaboration

    2014-12-01

    The J-PARC E15 experiment searches for the simplest kaonic nuclear bound state, K-pp, via the 3He(K-,n) reaction at the K1.8BR beam-line in the J-PARC hadron experimental facility. We performed the first data-taking in May, 2013, with 5 × 109 incident kaons on the 3He target. The preliminary results are reported focusing on the forward-neutron spectrum, which shows a clear peak structure composed of the quasi-elastic K-"n" → K-n and the charge-exchange K-"p" → bar K0n reactions as expected.

  10. Theory for supersolid 4He : Vacancy condensation facilitated by a low-energy bound state of a vacancy and an interstitial

    NASA Astrophysics Data System (ADS)

    Dai, Xi; Ma, Michael; Zhang, Fu-Chun

    2005-10-01

    Although both vacancies and interstitials have relatively high activation energies in the normal solid, we propose that a lower energy bound state of a vacancy and an interstitial may facilitate vacancy condensation to give supersolidity in 4He . We use a phenomenological two-band boson lattice model to demonstrate this new mechanism and discuss the possible relevance to the recently observed superfluidlike, nonclassical rotational inertial experiments of Kim and Chan in solid 4He . Some of our results may also be applicable to trapped bosons in optical lattices.

  11. Energy-Time Uncertainty Principle and Lower Bounds on Sojourn Time

    NASA Astrophysics Data System (ADS)

    Asch, Joachim; Bourget, Olivier; Cortés, Victor; Fernandez, Claudio

    2016-09-01

    One manifestation of quantum resonances is a large sojourn time, or autocorrelation, for states which are initially localized. We elaborate on Lavine's time-energy uncertainty principle and give an estimate on the sojourn time. For the case of perturbed embedded eigenstates the bound is explicit and involves Fermi's Golden Rule. It is valid for a very general class of systems. We illustrate the theory by applications to resonances for time dependent systems including the AC Stark effect as well as multistate systems.

  12. Rovibrational energy transfer in the He-C{sub 3} collision: Potential energy surface and bound states

    SciTech Connect

    Denis-Alpizar, Otoniel; Stoecklin, Thierry Halvick, Philippe

    2014-02-28

    We present a four-dimensional potential energy surface (PES) for the collision of C{sub 3} with He. Ab initio calculations were carried out at the coupled-cluster level with single and double excitations and a perturbative treatment of triple excitations, using a quadruple-zeta basis set and mid-bond functions. The global minimum of the potential energy is found to be −26.9 cm{sup −1} and corresponds to an almost T-shaped structure of the van der Waals complex along with a slightly bent configuration of C{sub 3}. This PES is used to determine the rovibrational energy levels of the He-C{sub 3} complex using the rigid monomer approximation (RMA) and the recently developed atom-rigid bender approach at the Close Coupling level (RB-CC). The calculated dissociation energies are −9.56 cm{sup −1} and −9.73 cm{sup −1}, respectively at the RMA and RB-CC levels. This is the first theoretical prediction of the bound levels of the He-C{sub 3} complex with the bending motion.

  13. Effect of bound state of water on hydronium ion mobility in hydrated Nafion using molecular dynamics simulations

    SciTech Connect

    Mabuchi, Takuya; Tokumasu, Takashi

    2014-09-14

    We have performed a detailed analysis of the structural properties of the sulfonate groups in terms of isolated and overlapped solvation shells in the nanostructure of hydrated Nafion membrane using classical molecular dynamics simulations. Our simulations have demonstrated the correlation between the two different areas in bound water region, i.e., the first solvation shell, and the vehicular transport of hydronium ions at different water contents. We have employed a model of the Nafion membrane using the improved force field, which is newly modified and validated by comparing the density and water diffusivity with those obtained experimentally. The first solvation shells were classified into the two types, the isolated area and the overlapped area. The mean residence times of solvent molecules explicitly showed the different behaviors in each of those areas in terms of the vehicular transport of protons: the diffusivity of classical hydronium ions in the overlapped area dominates their total diffusion at lower water contents while that in the isolated area dominates for their diffusion at higher water contents. The results provided insights into the importance role of those areas in the solvation shells for the diffusivity of vehicular transport of hydronium ions in hydrated Nafion membrane.

  14. Coherent Behavior and the Bound State of Water and K+ Imply Another Model of Bioenergetics: Negative Entropy Instead of High-energy Bonds

    PubMed Central

    Jaeken, Laurent; Vasilievich Matveev, Vladimir

    2012-01-01

    Observations of coherent cellular behavior cannot be integrated into widely accepted membrane (pump) theory (MT) and its steady state energetics because of the thermal noise of assumed ordinary cell water and freely soluble cytoplasmic K+. However, Ling disproved MT and proposed an alternative based on coherence, showing that rest (R) and action (A) are two different phases of protoplasm with different energy levels. The R-state is a coherent metastable low-entropy state as water and K+ are bound to unfolded proteins. The A-state is the higher-entropy state because water and K+ are free. The R-to-A phase transition is regarded as a mechanism to release energy for biological work, replacing the classical concept of high-energy bonds. Subsequent inactivation during the endergonic A-to-R phase transition needs an input of metabolic energy to restore the low entropy R-state. Matveev’s native aggregation hypothesis allows to integrate the energetic details of globular proteins into this view. PMID:23264833

  15. The Path Resistance Method for Bounding the Smallest Nontrivial Eigenvalue of a Laplacian

    NASA Technical Reports Server (NTRS)

    Guattery, Stephen; Leighton, Tom; Miller, Gary L.

    1997-01-01

    We introduce the path resistance method for lower bounds on the smallest nontrivial eigenvalue of the Laplacian matrix of a graph. The method is based on viewing the graph in terms of electrical circuits; it uses clique embeddings to produce lower bounds on lambda(sub 2) and star embeddings to produce lower bounds on the smallest Rayleigh quotient when there is a zero Dirichlet boundary condition. The method assigns priorities to the paths in the embedding; we show that, for an unweighted tree T, using uniform priorities for a clique embedding produces a lower bound on lambda(sub 2) that is off by at most an 0(log diameter(T)) factor. We show that the best bounds this method can produce for clique embeddings are the same as for a related method that uses clique embeddings and edge lengths to produce bounds.

  16. High-lying bound Rydberg states of excited Hg(6s6p {sup 3}P{sub 1}) atoms from two-color resonance ionization mass spectroscopy

    SciTech Connect

    Bisling, Peter; Dederichs, Jan; Neidhart, Bernd; Weitkamp, Claus

    1998-12-16

    Mercury isotopes are investigated with two-color resonance ionization mass spectroscopy (RIMS). Isotope shifts, hyperfine structure splittings, and the lifetime of the intermediate 6s6p {sup 3}P{sub 1} state are determined by RIMS. Ion yields at the threshold region in various static electric fields are measured in order to determine an extrapolated ionization energy value at zero field strength. New energy values for high-lying bound 6s nd {sup 3}D (21states of Hg isotopes are found under field-free conditions and with delayed, pulsed electric field ionization. To the author's knowledge this is the first time that isotopic effects on the ionization energy are deduced from the convergence limit of the Rydberg series.

  17. The interaction of He with vibrating HCN: potential energy surface, bound states, and rotationally inelastic cross sections.

    PubMed

    Denis-Alpizar, Otoniel; Stoecklin, Thierry; Halvick, Philippe; Dubernet, Marie-Lise

    2013-07-21

    A four-dimensional potential energy surface representing the interaction between He and hydrogen cyanide (HCN) subjected to bending vibrational motion is presented. Ab initio calculations were carried out at the coupled-cluster level with single and double excitations and a perturbative treatment of triple excitations, using a quadruple-zeta basis set and mid-bond functions. The global minimum is found in the linear He-HCN configuration with the H atom pointing towards helium at the intermolecular separation of 7.94 a0. The corresponding well depth is 30.35 cm(-1). First, the quality of the new potential has been tested by performing two comparisons with previous theoretical and experimental works. (i) The rovibrational energy levels of the He-HCN complex for a rigid linear configuration of the HCN molecule have been calculated. The dissociation energy is 8.99 cm(-1), which is slightly smaller than the semi-empirical value of 9.42 cm(-1). The transitions frequencies are found to be in good agreement with the experimental data. (ii) We performed close coupling calculations of the rotational de-excitation of rigid linear HCN in collision with He and observed a close similarity with the theoretical data published in a recent study. Second, the effects of the vibrational bending of HCN have been investigated, both for the bound levels of the He-HCN system and for the rotationally inelastic cross sections. This was performed with an approximate method using the average of the interaction potential over the vibrational bending wavefunction. While this improves slightly the comparison of calculated transitions frequencies with experiment, the cross sections remain very close to those obtained with rigid linear HCN. PMID:23883024

  18. A QM/MM Approach Using the AMOEBA Polarizable Embedding: From Ground State Energies to Electronic Excitations.

    PubMed

    Loco, Daniele; Polack, Étienne; Caprasecca, Stefano; Lagardère, Louis; Lipparini, Filippo; Piquemal, Jean-Philip; Mennucci, Benedetta

    2016-08-01

    A fully polarizable implementation of the hybrid quantum mechanics/molecular mechanics approach is presented, where the classical environment is described through the AMOEBA polarizable force field. A variational formalism, offering a self-consistent relaxation of both the MM induced dipoles and the QM electronic density, is used for ground state energies and extended to electronic excitations in the framework of time-dependent density functional theory combined with a state specific response of the classical part. An application to the calculation of the solvatochromism of the pyridinium N-phenolate betaine dye used to define the solvent ET(30) scale is presented. The results show that the QM/AMOEBA model not only properly describes specific and bulk effects in the ground state but it also correctly responds to the large change in the solute electronic charge distribution upon excitation. PMID:27340904

  19. Substrate-bound outward-open state of the betaine transporter BetP provides insights into Na+ coupling.

    PubMed

    Perez, Camilo; Faust, Belinda; Mehdipour, Ahmad Reza; Francesconi, Kevin A; Forrest, Lucy R; Ziegler, Christine

    2014-01-01

    The Na(+)-coupled betaine symporter BetP shares a highly conserved fold with other sequence unrelated secondary transporters, for example, with neurotransmitter symporters. Recently, we obtained atomic structures of BetP in distinct conformational states, which elucidated parts of its alternating-access mechanism. Here, we report a structure of BetP in a new outward-open state in complex with an anomalous scattering substrate, adding a fundamental piece to an unprecedented set of structural snapshots for a secondary transporter. In combination with molecular dynamics simulations these structural data highlight important features of the sequential formation of the substrate and sodium-binding sites, in which coordinating water molecules play a crucial role. We observe a strictly interdependent binding of betaine and sodium ions during the coupling process. All three sites undergo progressive reshaping and dehydration during the alternating-access cycle, with the most optimal coordination of all substrates found in the closed state. PMID:25023443

  20. Embedded yet Separate: Tensions in Voluntary Sector Working to Support Mental Health in State-Run Schools

    ERIC Educational Resources Information Center

    Spratt, Jennifer; Shucksmith, Janet; Philip, Kate; Watson, Cate

    2007-01-01

    The policy agenda of the UK government has repositioned the voluntary sector as a key player in the delivery of locally responsive, "bottom up" services to address the complex problems of social exclusion, reaching out to sectors of the community which are beyond the grasp of traditional state or market providers. This has drawn many voluntary…