International Nuclear Information System (INIS)
We discuss the structure and formation of deeply bound π- states in heavy nuclei, which are expected to be narrow due to the repulsive π--nucleus interaction. Possible experiments to produce those states are described. (author)
International Nuclear Information System (INIS)
The standard method of pionic atom formation does not produce deeply bound pionic atoms. A study is made on the properties of deeply bound pionic atom states by using the standard pion-nucleus optical potential. Another study is made to estimate the cross sections of the formation of ls pionic atom states by various methods. The pion-nucleus optical potential is determined by weakly bound pionic atom states and pion nucleus scattering. Although this potential may not be valid for deeply bound pionic atoms, it should provide some hint on binding energies and level widths of deeply bound states. The width of the ls state comes out to be 0.3 MeV and is well separated from the rest. The charge dependence of the ls state is investigated. The binding energies and the widths increase linearly with Z azbove a Z of 30. The report then discusses various methods to populate deeply bound pionic atoms. In particular, 'pion exchange' reactions are proposed. (n, pπ) reaction is discussed first. The cross section is calculated by assuming the in- and out-going nucleons on-shell and the produced pion in (n1) pionic atom states. Then, (n, dπ-) cross sections are estimated. (p, 2Heπ-) reaction would have cross sections similar to the cross section of (n, dπ-) reaction. In conclusion, it seems best to do (n, p) experiment on heavy nuclei for deeply bound pionic atom. (Nogami, K.)
Deeply bound pionic atoms: the story of an ongoing race
International Nuclear Information System (INIS)
A short review is made of the steps of the Valencia group in the search for suitable reactions to detect deeply bound pionic states and how these steps were influenced by the parallel steps of the Tokyo team. The present situation and future prospects are outlined. (orig.)
Calculations of deeply bound pionic states in heavy and superheavy atoms
International Nuclear Information System (INIS)
Binding energies and widths of pions bound in the 1s-state of heavy and superheavy atoms are evaluated. The repulsive strong interaction lowers the Coulomb binding energy by up to 50%. The energy width of the strongest bound state investigated becomes comparable with the binding energy. No drastic consequence on the pion propagation in nuclear matter is expected. (orig.)
The three-nucleon bound state with isobaric and pionic degrees of freedom
International Nuclear Information System (INIS)
Wave function components containing a single Δ-isobar are included in the calculation of the three-nucleon bound states. The two-nucleon interaction acts in all partial waves up to total angular momentum I=2. The presence of a Δ-isobar increases the three-nucleon binding energy by about 0.3 MeV, 0.6 MeV repulsion being a dispersive two-body effect, 0.9 MeV attraction arising from the three-nucleon force with intermediate Δ-isobar. The effect of the Δ on the three-nucleon charge and magnetic form factors is investigated. The possibility of treating the Δ-isobar as a dynamic pion-nucleon system in nuclear structure and nuclear-structure corrections beyond single Δ excitation in the coupled channel approach are also discussed
Measurement of the Strong Interaction Shift and Width of the Ground State of Pionic Hydrogen
Energy Technology Data Exchange (ETDEWEB)
Manil, B., E-mail: manil@spectro.jussieu.fr [Universite Pierre et Marie Curie, Laboratoire Kastler-Brossel, Unite Mixte de Recherche du CNRS no C8552 (France); Anagnostopoulos, D. F. [University of Ioannina, Department of Material Science (Greece); Biri, S. [ATOMKI, Hungary Academie of Science (Hungary); Borchert, G. L. [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Breunlich, W. [IMEP, Osterreichisch Akademie der Wissenschaften (Austria); Egger, J. P. [Institut de Physique de l' Universite de Neuchatel (Switzerland); Gotta, D. [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Gruber, A. [IMEP, Osterreichisch Akademie der Wissenschaften (Austria); Hennebach, M.; Indelicato, P. [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Jensen, T. [University of Aarhus (Denmark); Liu, Y. W.; Markushin, V. [Paul Scherrer Institut (Switzerland); Nelms, N. [University of Leicester, Department of Physics and Astronomy (United Kingdom); Simons, L. M. [Paul Scherrer Institut (Switzerland); Zmeskal, H. [IMEP, Osterreichisch Akademie der Wissenschaften (Austria)
2003-03-15
An experiment to measure the strong interaction width ({Gamma}{sub 1s}) and shift ({epsilon}{sub 1s}) of the ground state of pionic hydrogen ({pi}{sup -}p), in order to determine the isospin separated scattering lengths (a{sup +} and a{sup -}) with a relative accuracy of better than 10{sup -2}, has been undertaken at the Paul Scherrer Institute (PSI). This measurement is based on high-precision X-ray spectroscopy of the np{sup {yields}1}s transitions pionic hydrogen ({pi}{sup -}p). A preliminary analysis of the data taken in December 2000 is presented.
Real-pion states formed by virtual-pion beam
International Nuclear Information System (INIS)
Deeply bound pionic states are discussed from various points of view; highly excited nuclear states as a cluster family of pionic bound states, Σ atom/Σ hypernuclei, halo-like density distributions, virtual pion beam to produce pionic states, etc. (author)
Determination of the hadronic width of the ground state in pionic hydrogen
International Nuclear Information System (INIS)
In a new high-precision experiment at the Paul Scherrer Institut (PSI), the hadronic shift (ε1s) and width (Γ1s) of the ground state of pionic hydrogen, which are directly connected to the pion-nucleon isospin scattering lengths, were remeasured (PSI-Experiment R-98-01). The results can be confronted with recent work of effective field theories defined in the low-energy limit of quantum chromodynamics (QCD), such as, e. g., chiral perturbation theory (ChPT). In addition, Γ1s is connected to the pion-nucleon coupling constant fπN. A precisely known value for fπN allows an accurate determination of the Goldberger-Treiman discrepancy, which constitutes a measure of chiral symmetry breaking. This contribution is mainly devoted to describe a method for an accurate extraction of the hadronic width from the π-H data.
Strauch, Th; Anagnostopoulos, D; Bühler, P; Covita, D S; Gorke, H; Gotta, D; Gruber, A; Hirtl, A; Indelicato, P; Bigot, E -O Le; Nekipelov, M; Santos, J M F dos; Schmid, Ph; Schlesser, S; Simons, L M; Trassinelli, M; Veloso, J F C A; Zmeskal, J
2010-01-01
The strong interaction shift $\\epsilon$ and broadening {\\Gamma} in pionic deuterium have been determined in a high statistics study of the {\\pi}D(3p - 1s) X-ray transition using a high-resolution crystal spectrometer. The pionic deuterium shift will provide constraints for the pion-nucleon isospin scattering lengths extracted from measurements of shift and broadening in pionic hydrogen. The hadronic broadening is related to pion absorption and production at threshold. The results are \\epsilon = (-2356 {\\pm} 31)meV (repulsive) and {\\Gamma}1s = (1171+23/-49) meV yielding for the complex {\\pi}D scattering length a = [-(24.99 {\\pm} 0.33) + i (6.22+0.12/-0.26 )]x10-3/m{\\pi}. From the imaginary part, the threshold parameter for pion production is obtained to be {\\alpha} = (251 +5/-11) {\\mu}b. This allows, in addition, and by using results from pion absorption in 3He at threshold, the determination of the effective couplings g0 and g1 for s-wave pion absorption on isoscalar and isovector NN pairs.
Energy Technology Data Exchange (ETDEWEB)
Strauch, T.; Gotta, D.; Nekipelov, M. [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany); Amaro, F.D.; Santos, J.M.F. dos [Coimbra University, Department of Physics, Coimbra (Portugal); Anagnostopoulos, D.F. [University of Ioannina, Department of Materials Science and Engineering, Ioannina (Greece); Buehler, P.; Gruber, A.; Hirtl, A.; Schmid, P.; Zmeskal, J. [Austrian Academy of Sciences, Stefan Meyer Institut for Subatomic Physics, Vienna (Austria); Covita, D.S. [Coimbra University, Department of Physics, Coimbra (Portugal); Paul Scherrer Institut, Laboratory for Particle Physics, Villigen (Switzerland); Gorke, H. [Forschungszentrum Juelich GmbH, Zentralinstitut fuer Elektronik, Juelich (Germany); Indelicato, P.; Le Bigot, E.O.; Schlesser, S.; Trassinelli, M. [UPMC-Paris 6, ENS, CNRS, Laboratoire Kastler Brossel, Paris (France); Simons, L.M. [Paul Scherrer Institut, Laboratory for Particle Physics, Villigen (Switzerland); Veloso, J.F.C.A. [Aveiro University, I3N, Department of Physics, Aveiro (Portugal)
2011-07-15
The strong-interaction shift {epsilon}{sub 1s}{sup {pi}}{sup D} and broadening {gamma}{sub 1s}{sup {pi}}{sup D} in pionic deuterium have been determined in a high statistics study of the {pi}D(3p-1s) X-ray transition using a high-resolution crystal spectrometer. The pionic deuterium shift will provide constraints for the pion-nucleon isospin scattering lengths extracted from measurements of shift and broadening in pionic hydrogen. The hadronic broadening is related to pion absorption and production at threshold. The results are {epsilon}{sub 1s}{sup {pi}}{sup D}=(-2356 {+-} 31) meV (repulsive) and {gamma}{sub 1s}{sup {pi}}{sup D} meV yielding for the complex {pi}D scattering length a{sub {pi}}{sub D}=[-(24.99 {+-}0.33)+i(6.22{sub -0.26} {sup +0.12}) ]x 10{sup -3} m{sub {pi}}{sup -1}. From the imaginary part, the threshold parameter for pion production is obtained to be {alpha} = (251{sub -11} {sup +5}){mu}b. This allows, in addition, and by using results from pion absorption in {sup 3}He at threshold, the determination of the effective couplings g{sub 0} and g{sub 1} for s-wave pion absorption on isoscalar and isovector NN pairs. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Gotta, D., E-mail: d.gotta@fz-juelich.de [Forschungszentrum Jülich GmbH and JHCP (Germany); Amaro, F. D. [Coimbra University, Department of Physics (Portugal); Anagnostopoulos, D. F. [University of Ioannina, Department of Materials Science and Engineering (Greece); Bühler, P. [Stefan Meyer Institut, Austrian Academy of Sciences (Austria); Gorke, H. [Forschungszentrum Jülich GmbH and JHCP (Germany); Covita, D. S. [Coimbra University, Department of Physics (Portugal); Fuhrmann, H.; Gruber, A. [Stefan Meyer Institut, Austrian Academy of Sciences (Austria); Hennebach, M. [Forschungszentrum Jülich GmbH and JHCP (Germany); Hirtl, A.; Ishiwatari, T. [Stefan Meyer Institut, Austrian Academy of Sciences (Austria); Indelicato, P. [LKB, UPMC-Paris 6, ENS, CNRS (France); Jensen, T. S. [Ringkjøbing Gymnasium (Denmark); Bigot, E.-O. Le [LKB, UPMC-Paris 6, ENS, CNRS (France); Markushin, V. E. [Paul Scherrer Institut (PSI) (Switzerland); Marton, J. [Stefan Meyer Institut, Austrian Academy of Sciences (Austria); Nekipelov, M. [Forschungszentrum Jülich GmbH and JHCP (Germany); Pomerantsev, V. N.; Popov, V. P. [Skobeltsyn Institut of Nuclear Physics, Lomonossov Moscow State University (Russian Federation); Santos, J. M. F. dos [Coimbra University, Department of Physics (Portugal); and others
2015-08-15
Pion-nucleon scattering lengths are directly related to the ground-state level shift and broadening in pionic hydrogen as well as to the pionic deuterium level shift. The level broadening in deuterium measures the strength of pion threshold-production in proton-proton reactions. However, collisional processes during the atomic de-excitation cascade considerably complicate the analysis of X-ray line shapes in order to extract the hadronic broadening. Therefore, additionally the purely electromagnetic twin system muonic hydrogen was studied. Results of these experiments performed at PSI by using a high-resolution crystal spectrometer are discussed in the context with a new analysis approach for the hadronic broadening.
International Nuclear Information System (INIS)
Pion-nucleon scattering lengths are directly related to the ground-state level shift and broadening in pionic hydrogen as well as to the pionic deuterium level shift. The level broadening in deuterium measures the strength of pion threshold-production in proton-proton reactions. However, collisional processes during the atomic de-excitation cascade considerably complicate the analysis of X-ray line shapes in order to extract the hadronic broadening. Therefore, additionally the purely electromagnetic twin system muonic hydrogen was studied. Results of these experiments performed at PSI by using a high-resolution crystal spectrometer are discussed in the context with a new analysis approach for the hadronic broadening
Hoyer, Paul
2016-01-01
Even a first approximation of bound states requires contributions of all powers in the coupling. This means that the concept of "lowest order bound state" needs to be defined. In these lectures I discuss the "Born" (no loop, lowest order in $\\hbar$) approximation. Born level states are bound by gauge fields which satisfy the classical field equations. As a check of the method, Positronium states of any momentum are determined as eigenstates of the QED Hamiltonian, quantized at equal time. Analogously, states bound by a strong external field $A^\\mu(\\xv)$ are found as eigenstates of the Dirac Hamiltonian. Their Fock states have dynamically created $e^+e^-$ pairs, whose distribution is determined by the Dirac wave function. The linear potential of $D=1+1$ dimensions confines electrons but repels positrons. As a result, the mass spectrum is continuous and the wave functions have features of both bound states and plane waves. The classical solutions of Gauss' law are explored for hadrons in QCD. A non-vanishing bo...
Reflecting Magnon Bound States
Ahn, C; Rey, S J
2008-01-01
In N=4 super Yang-Mills spin chain, we compute reflection amplitudes of magnon bound-state off giant graviton. We first compute the reflection amplitude off Y=0 brane boundary and compare it with the scattering amplitude between two magnon bound-states in the bulk. We find that analytic structure of the two amplitudes are intimately related each other: the boundary reflection amplitude is a square-root of the bulk scattering amplitude. Using such relation as a guide and taking known results at weak and strong coupling limits as inputs, we find the reflection amplitude of an elementary magnon off Z=0 giant graviton boundary. The reflection phase factor is shown to solve crossing and unitarity relations. We then compute the reflection amplitude of magnon bound-state off the Z=0 brane boundary and observe that its analytic structures are again intimately related to the bulk scattering and the Y=0 boundary reflection amplitudes. We also take dyonic giant magnon limit of these reflection amplitudes and confirm tha...
Bound states and the Bekenstein bound
Bousso, R
2004-01-01
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 a. 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.
DEFF Research Database (Denmark)
Faupin, Jeremy; Møller, Jacob Schach; Skibsted, Erik
2011-01-01
We study regularity of bound states pertaining to embedded eigenvalues of a self-adjoint operator H, with respect to an auxiliary operator A that is conjugate to H in the sense of Mourre. We work within the framework of singular Mourre theory which enables us to deal with confined massless Pauli......–Fierz models, our primary example, and many-body AC-Stark Hamiltonians. In the simpler context of regular Mourre theory, our results boil down to an improvement of results obtained recently in [8, 9]....
Hadronic shift in pionic hydrogen
Hennebach, M; Dax, A; Fuhrmann, H; Gotta, D; Gruber, A; Hirtl, A; Indelicato, P; Liu, Y -W; Manil, B; Markushin, V E; Hassani, A J Rusi el; Simons, L M; Trassinelli, M; Zmeskal, J
2014-01-01
The hadronic shift in pionic hydrogen has been redetermined to be $\\epsilon_{1s}=7.086\\,\\pm\\,0.007(stat)\\,\\pm\\,0.006(sys)$\\,eV by X-ray spectroscopy of ground state transitions applying various energy calibration schemes. The experiment was performed at the high-intensity low-energy pion beam of the Paul Scherrer Institut by using the cyclotron trap and an ultimate resolution bent crystal Bragg spectrometer.
Precision measurements in pionic hydrogen
Energy Technology Data Exchange (ETDEWEB)
Anagnostopoulos, D.F.; Cargnelli, M.; Fuhrmann, H.; Giersch, M.; Gotta, D.; Gruber, A.; Hennebach, M.; Hirtl, A.; Indelicato, P.; Liu, Y.W.; Manil, B.; Markushin, V.E.; Marton, J.; Nelms, N.; Simons, L.M.; Trasinelli, M.; Zmeskal, J
2003-06-30
The strong interaction in the pion nucleon system leads to a shift and a broadening of the 1s-ground state in pionic hydrogen. These two quantities are being measured in an experiment at the Paul Scherrer Institute with much improved precision and allow an experimental test of recent calculations in the framework of Chiral Perturbation Theory. The experimental techniques using high resolution crystal spectroscopy are described as well as recent results.
Hadronic shift in pionic hydrogen
International Nuclear Information System (INIS)
The hadronic shift in pionic hydrogen has been redetermined to be ε 1s = 7.086 ± 0.007(stat) ± 0.006(sys) eV by X-ray spectroscopy of ground-state transitions applying various energy calibration schemes. The experiment was performed at the high-intensity low-energy pion beam of the Paul Scherrer Institut by using the cyclotron trap and an ultimate-resolution Bragg spectrometer with bent crystals. (orig.)
Hadronic shift in pionic hydrogen
Energy Technology Data Exchange (ETDEWEB)
Hennebach, M.; Gotta, D. [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany); Anagnostopoulos, D.F. [University of Ioannina, Department of Materials Science and Engineering, Ioannina (Greece); Dax, A.; Liu, Y.W.; Markushin, V.E.; Simons, L.M. [Paul Scherrer Institut, Laboratory for Particle Physics, Villigen (Switzerland); Fuhrmann, H.; Gruber, A.; Hirtl, A.; Zmeskal, J. [Austrian Academy of Sciences, Stefan Meyer Institute for Subatomic Physics, Vienna (Austria); Indelicato, P. [UPMC Univ. Paris 06, Laboratoire Kastler Brossel, Sorbonne Universites, Paris (France); CNRS, Laboratoire Kastler Brossel, Paris (France); Departement de Physique de l' Ecole Normale Superieure, Laboratoire Kastler Brossel, Paris (France); Manil, B. [UPMC Univ. Paris 06, Laboratoire Kastler Brossel, Sorbonne Universites, Paris (France); Rusi el Hassani, A.J. [Universite Abdelmalek Essaadi, Faculte des Sciences et Techniques, Tanger (Morocco); Trassinelli, M. [Sorbonne Universites, Institut des NanoSciences de Paris, Paris (France); CNRS, Institut des NanoSciences de Paris, Paris (France)
2014-12-01
The hadronic shift in pionic hydrogen has been redetermined to be ε {sub 1s} = 7.086 ± 0.007(stat) ± 0.006(sys) eV by X-ray spectroscopy of ground-state transitions applying various energy calibration schemes. The experiment was performed at the high-intensity low-energy pion beam of the Paul Scherrer Institut by using the cyclotron trap and an ultimate-resolution Bragg spectrometer with bent crystals. (orig.)
Measurement of Pionic 121Sn atoms at the RI beam factory
International Nuclear Information System (INIS)
We have measured the energy spectrum of pionic 121Sn atoms by missing-mass spectroscopy of the 122Sn(d, 3He) reaction near the π − emission threshold. The measurement serves as a pilot experiment for high precision systematic spectroscopy of deeply bound pionic atoms in a new pionic Atom Factory project (piAF) at the RI beam factory (RIBF) of RIKEN. The status of the analysis is reported.
Schulz, M D; Vidal, J
2016-01-01
We discuss the emergence of bound states in the low-energy spectrum of the string-net Hamiltonian in the presence of a string tension. In the ladder geometry, we show that a single bound state arises either for a finite tension or in the zero-tension limit depending on the theory considered. In the latter case, we perturbatively compute the binding energy as a function of the total quantum dimension. We also address this issue in the honeycomb lattice where the number of bound states in the topological phase depends on the total quantum dimension. Finally, the internal structure of these bound states is analyzed in the zero-tension limit.
Bound anionic states of adenine
Harańczyk, Maciej; Gutowski, Maciej; Li, Xiang; Bowen, Kit H.
2007-01-01
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...
Bound states of 'dressed' particles
International Nuclear Information System (INIS)
A new approach to the problem of bound states in relativistic quantum field theories is suggested. It uses the creation - destruction operators of 'dresses' particles which have been granted by Faddeev's (1963) 'dressing' formalism. Peculiarities of the proposed approach as compared to the known ones are discussed. 8 refs. (author)
Pionic Fusion in Light-Ion Systems
International Nuclear Information System (INIS)
Two pionic fusion experiments have been performed using the AGOR accelerator facility at KVI in order to study the role of pions in the nuclear interaction. Pionic fusion is a highly coherent process in which two nuclei fuse to a united nucleus and the available centre-of-mass energy is emitted in the pion channel. The reactions 4He(3He,π0)7Be and 6Li(4He,π0)10B were performed at beam energies only about 10 MeV above the coherent pion production threshold (256 MeV and 236.4 MeV, respectively). In order to provide sensitivity to the full dynamics and relevant processes involved in the pionic fusion reaction, almost the full angular distributions of neutral pions have been determined. To this end the fusion products have been identified in the focal plane of the magnetic big-bite spectrometer and the photons from neutral pion decay were detected in the spherical Plastic Ball detector. Detailed simulations of the response of the complete experimental setup were performed in order to verify the unique identification of the exclusive final state. Angular distributions are compared to results of a model [1] based on clustering correlations in nuclei. Using a phenomenological analysis of the angular distribution by Legendre Polynomials, the structure of the angular distributions could be analyzed and the extrapolation into missing parts was performed to determine the total cross section. The results of this analysis confirm the importance of the clustering correlations for both reactions. The mass dependence of the total pionic fusion cross sections is in agreement with the results from existing models extrapolated to the reactions studied here.(author)
Bound entangled states invariant under Ux
Institute of Scientific and Technical Information of China (English)
Wang Zhen; Wang Zhi-Xi
2008-01-01
This paper obtains an entangled condition for isotropic-like states by using an atomic map. It constructs a class of bound entangled states from the entangled condition and shows that the partial transposition of the state from the constructed bound entangled class is an edge bound entangled state by using range criterion.
Antibaryon-nucleus bound states
Hrtánková, J
2014-01-01
We calculated antibaryon ($\\bar{B}$ = $\\bar{p}$, $\\bar{\\Lambda}$, $\\bar{\\Sigma}$, $\\bar{\\Xi}$) bound states in selected nuclei within the relativistic mean-field (RMF) model. The G-parity motivated $\\bar{B}$-meson coupling constants were scaled to yield corresponding potentials consistent with available experimental data. Large polarization of the nuclear core caused by $\\bar{B}$ was confirmed. The $\\bar{p}$ annihilation in the nuclear medium was incorporated by including a phenomenological imaginary part of the optical potential. The calculations using a complex $\\bar{p}$-nucleus potential were performed fully self-consistently. The $\\bar{p}$ widths significantly decrease when the phase space reduction is considered for $\\bar{p}$ annihilation products, but they still remain sizeable for potentials consistent with $\\bar{p}$-atom data.
Instanton bound states in ABJM theory
Energy Technology Data Exchange (ETDEWEB)
Hatsuda, Yasuyuki [DESY Hamburg (Germany). Theory Group; Tokyo Institute of Technology (Japan). Dept. of Physics; Moriyama, Sanefumi [Nagoya Univ. (Japan). Kobayashi Maskawa Inst. and Graduate School of Mathematics; Okuyama, Kazumi [Shinshu Univ., Matsumoto, Nagano (Japan). Dept. of Physics
2013-06-15
The partition function of the ABJM theory receives non-perturbative corrections due to instanton effects. We study these non-perturbative corrections, including bound states of worldsheet instantons and membrane instantons, in the Fermi-gas approach. We require that the total non-perturbative correction should be always finite for arbitrary Chern-Simons level. This finiteness is realized quite non-trivially because each bound state contribution naively diverges at some levels. The poles of each contribution should be canceled out in total. We use this pole cancellation mechanism to find unknown bound state corrections from known ones. We conjecture a general expression of the bound state contribution. Summing up all the bound state contributions, we find that the effect of bound states is simply incorporated into the worldsheet instanton correction by a redefinition of the chemical potential in the Fermi-gas system. Analytic expressions of the 3- and 4-membrane instanton corrections are also proposed.
Bound States of Double Flavor Hyperons
Froemel, F; Riska, D O
2005-01-01
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 $\\Xi_c^{'}$ and $\\Xi_{cc}$ charm hyperons as well as between $\\Xi$ hyperons and double-charm hyperons. Bound states between two $\\Sigma_c$ hyperons are also likely. In the case of beauty hyperons the corresponding states are likely to be deeply bound.
Bound states of heavy flavor hyperons
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.
Quasi-bound states in continuum
International Nuclear Information System (INIS)
We report the prediction of quasi-bound states (resonant states with very long lifetimes) that occur in the eigenvalue continuum of propagating states for a wide region of parameter space. These quasi-bound states are generated in a quantum wire with two channels and an adatom, when the energy bands of the two channels overlap. A would-be bound state that lays just below the upper energy band is slightly destabilized by the lower energy band and thereby becomes a resonant state with a very long lifetime (a second QBIC lays above the lower energy band). (author)
Coulomb bound states of strongly interacting photons
Maghrebi, M F; Bienias, P; Choi, S; Martin, I; Firstenberg, O; Lukin, M D; Büchler, H P; Gorshkov, A V
2015-01-01
We show that two photons coupled to Rydberg states via electromagnetically induced transparency can interact via an effective Coulomb potential. This interaction gives rise to a continuum of two-body bound states. Within the continuum, metastable bound states are distinguished in analogy with quasi-bound states tunneling through a potential barrier. We find multiple branches of metastable bound states whose energy spectrum is governed by the Coulomb potential, thus obtaining a photonic analogue of the hydrogen atom. Under certain conditions, the wavefunction resembles that of a diatomic molecule in which the two polaritons are separated by a finite "bond length." These states propagate with a negative group velocity in the medium, allowing for a simple preparation and detection scheme, before they slowly decay to pairs of bound Rydberg atoms.
Bound states of singlet quarks at LHC
Krasnikov, N. V.
1996-01-01
We discuss the discovery potential of the bound states of singlet quarks at LHC. We find that it is possible to discover bound states of singlet quarks at LHC with singlet quark masses up to 300 Gev for $e_{Q} = \\frac{2}{3}$ and up to 200 Gev for $e_{Q} = -\\frac{1}{3}$.
High-Precision Measurement of Strong-Interaction Effects in Pionic Deuterium
Strauch, Thomas
2009-01-01
The hadronic ground state shift and width in pionic deuterium (piD) were measured with high precision at the pion factory of the Paul Scherrer Institut (PSI), Switzerland (PSI-Experiment R-06.03). The shift in pionic deuterium is directly related to the pion-nucleon isospin scattering lengths as measured from the shift and broadening in pionic hydrogen (piH)(PSI-Experiment R-98.01). The combination of the high-precision results from piH with the value from piD will provide a decisive constrai...
Probing bound states of D-branes
Lifschytz, G
1996-01-01
A zero-brane is used to probe non-threshold BPS bound states of ($p$, $p+2$,$p+4$)-branes. At long distances the stringy calculation agrees with the supergravity calculations. The supergravity description is given, using the interpretation of the $D=8$ dyonic membrane as the bound state of a two-brane inside a four-brane. We investigate the short distance structure of these bound states, compute the phase shift of the scattered zero-brane and find the bound states characteristic size. It is found that there should be a supersymmetric solution of type IIa supergravity, describing a bound state of a zero-brane and two orthogonal two-brane, all inside a four-brane , with an additional unbound zero-brane. We comment on the relationship between $p$-branes and $(p-2)$-branes.
Coulomb Bound States of Strongly Interacting Photons
Maghrebi, M. F.; Gullans, M. J.; Bienias, P.; Choi, S.; Martin, I.; Firstenberg, O.; Lukin, M. D.; Büchler, H. P.; Gorshkov, A. V.
2015-09-01
We show that two photons coupled to Rydberg states via electromagnetically induced transparency can interact via an effective Coulomb potential. This interaction gives rise to a continuum of two-body bound states. Within the continuum, metastable bound states are distinguished in analogy with quasibound states tunneling through a potential barrier. We find multiple branches of metastable bound states whose energy spectrum is governed by the Coulomb potential, thus obtaining a photonic analogue of the hydrogen atom. Under certain conditions, the wave function resembles that of a diatomic molecule in which the two polaritons are separated by a finite "bond length." These states propagate with a negative group velocity in the medium, allowing for a simple preparation and detection scheme, before they slowly decay to pairs of bound Rydberg atoms.
On the reflection of magnon bound states
MacKay, Niall
2010-01-01
We investigate the reflection of two-particle bound states of a free open string in the light-cone AdS_5 x S^5 string sigma model, for large angular momentum J=J_56 and ending on a D7 brane which wraps the entire AdS_5 and a maximal S^3 of S^5. We use the superspace formalism to analyse fundamental and two-particle bound states in the cases of supersymmetry-preserving and broken-supersymmetry boundaries. We find the boundary S-matrices corresponding to bound states both in the bulk and on the boundary.
Formation spectra of pionic atoms in the Green's function method
Ikeno, Natsumi; Yamagata-Sekihara, Junko; Nagahiro, Hideko; Hirenzaki, Satoru
2015-03-01
We study the formation spectra of deeply bound pionic atoms in the (d, ^3He) reactions using the Green's function method, stimulated by recent developments in experimental techniques. The Green's function method is considered to be a better theoretical formalism than the effective number approach to evaluate the formation rate of unstable systems. We compare the calculated results by the Green's function method with those by the effective number approach in various cases. We find that the differences between the results obtained by both methods are reasonably small and we can reaffirm that the effective number approach is a good theoretical method for the analyses of the previous experimental data with typical binding-energy errors of Δ B.E. ≳ 20keV for the deeply bound pionic atoms. On the other hand, we think that theoretical results using the Green's function method will be necessary in the near future to deduce precise information on the pion properties in nuclei from analyses of the pionic atom data with better accuracy than before.
Black Hole Bound State Metamorphosis
Chowdhury, Abhishek; Saha, Arunabha; Sen, Ashoke
2012-01-01
N=4 supersymmetric string theories contain negative discriminant states whose numbers are known precisely from microscopic counting formulae. On the macroscopic side, these results can be reproduced by regarding these states as multi-centered black hole configurations provided we make certain identification of apparently distinct multi-centered black hole configurations according to a precise set of rules. In this paper we provide a physical explanation of such identifications, thereby establishing that multi-centered black hole configurations reproduce correctly the microscopic results for the number of negative discriminant states without any ad hoc assumption.
Introduction to QCD - a bound state perspective
Hoyer, Paul
2011-01-01
These lecture notes focus on the bound state sector of QCD. Motivated by data which suggests that the strong coupling \\alpha_s(Q) freezes at low Q, and by similarities between the spectra of hadrons and atoms, I discuss if and how QCD bound states may be treated perturbatively. I recall the basic principles of perturbative gauge theory bound states at lowest order in the \\hbar expansion. Born level amplitudes are insensitive to the i\\epsilon prescription of propagators, which allows to eliminate the Z-diagrams of relativistic, time-ordered Coulomb interactions. The Dirac wave function thus describes a single electron which propagates forward in time only, even though the bound state has any number of pair constituents when Feynman propagators are used. In the absence of an external potential, states that are bound by the Coulomb attraction of their constituents can be analogously described using only their valence degrees of freedom. The instantaneous A^0 field is determined by Gauss' law for each wave functi...
Bound - states for truncated Coulomb potentials
Odeh, Maen; Mustafa, Omar
2000-01-01
The pseudoperturbative shifted - $l$ expansion technique PSLET is generalized for states with arbitrary number of nodal zeros. Bound- states energy eigenvalues for two truncated coulombic potentials are calculated using PSLET. In contrast with shifted large-N expansion technique, PSLET results compare excellently with those from direct numerical integration.
Sethi, S K; Sethi, Savdeep; Stern, Mark
1998-01-01
We study the existence of D-brane bound states at threshold in Type II string theories. In a number of situations, we can reduce the question of existence to quadrature, and the study of a particular limit of the propagator for the system of D-branes. This involves a derivation of an index theorem for a family of non-Fredholm operators. In support of the conjectured relation between compactified eleven-dimensional supergravity and Type IIA string theory, we show that a bound state exists for two coincident zero-branes. This result also provides support for the conjectured description of M-theory as a matrix model. In addition, we provide further evidence that there are no BPS bound states for two and three-branes twice wrapped on Calabi-Yau vanishing cycles.
Torons and D-Brane Bound States
Guralnik, Z.; Ramgoolam, S.
1997-01-01
We interpret instantons on a torus with twisted boundary conditions, in terms of bound states of branes. The interplay between the SU(N) and U(1) parts of the U(N) theory of N 4-branes allows the construction of a variety of bound states. The SU(N) and U(1) parts can contribute fractional amounts to the total instanton number which is integral. The geometry of non-self intersecting two-cycles in $T^4$ sheds some light on a number of properties of these solutions.
Spin and relativistic motion of bound states
JÃ€rvinen, Matti
2007-01-01
The wave functions of moving bound states may be expected to contract in the direction of motion, in analogy to a rigid rod in classical special relativity, when the constituents are at equal (ordinary) time. Indeed, the Lorentz contraction of wave functions is often appealed to in qualitative discussions. However, only few field theory studies exist of equal-time wave functions in motion. In this thesis I use the Bethe-Salpeter formalism to study the wave function of a weakly bound state suc...
Do $\\Xi\\Xi$ bound states exist?
Haidenbauer, J; Petschauer, S
2014-01-01
The existence of baryon-baryon bound states in the strangeness sector is examined in the framework of SU(3) chiral effective field theory. Specifically, the role of SU(3) symmetry breaking contact terms that arise at next-to-leading order in the employed Weinberg power counting scheme is explored. We focus on the 1S0 partial wave and on baryon-baryon channels with maximal isospin since in this case there are only two independent SU(3) symmetry breaking contact terms. At the same time, those are the channels where most of the bound states have been predicted in the past. Utilizing $pp$ phase shifts and $\\Sigma^+ p$ cross section data allows us to pin down one of the SU(3) symmetry breaking contact terms and a clear indication for the decrease of attraction when going from the NN system to strangeness S=-2 is found, which rules out a bound state for $\\Sigma\\Sigma$ with isospin I=2. Assuming that the trend observed for S=0 to S=-2 is not reversed when going to $\\Xi\\Sigma$ and $\\Xi\\Xi$ makes also bound states in ...
Scattering theory methods for bound state problems
International Nuclear Information System (INIS)
For the analysis of the properties of a bound state system one may use in place of the Schroedinger equation the Lippmann-Schwinger (LS) equation for the wave function or the LS equation for the reactance operator. Use of the LS equation for the reactance operator constrains the solution to have correct asymptotic behaviour, so this approach would appear to be desirable when the bound state wave function is to be used to calculate particle transfer form factors. The Schroedinger equation based N-level analysis of the s-wave bound states of a square well is compared to the ones based on the LS equation. It is found that the LS equation methods work better than the Schroedinger equation method. The method that uses the LS equation for the wave function gives the best results for the wave functions while the method that uses the LS equation for the reactance operator gives the best results for the binding energies. The accuracy of the reactance operator based method is remarkably insensitive to changes in the oscillator constant used for the harmonic oscillator function basis set. It is also remarkably insensitive to the number of nodes in the bound state wave function. (Auth.)
Relativistic bound states at Born level
Hoyer, Paul
2012-01-01
Theoretical and phenomenological studies indicate that the QCD coupling \\alpha_s(Q^2) freezes in the infrared. Hadrons may then be described by a perturbative expansion around "Born" states bound only by a confining potential. A linear potential results from the QCD equations of motion when Gauss' law for A^0 is solved with F_{\\mu\
On the Bound States of Matrix Strings
Sahakian, Vatche
1997-01-01
We investigate excitations in Matrix Theory on T^2 corresponding to bound states of strings. We demonstrate the Dirichlet aspect of R-R charged vacua through a non-trivial connection between the U(1) and SU(n) sectors of the matrix SYM.
Construction of bound entangled states based on permutation operators
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.
Deeply bound kaonic states in nuclei
Institute of Scientific and Technical Information of China (English)
LI Yi-He; WU Shi-Shu
2009-01-01
Using a new phenomenological (K)N interaction which reproduces A(1405) as an I = 0 bound state of (K)N, we have investigated K- -3 He(T = 0) and K- -4 He(T = 1/2) within the framework of the Brueckner-Hartree-Fock(BHF) theory. Our calculations show that the above kaonic nuclear systems are both deeply bound. The binding energy BK- is 124.4 MeV(94.1 MeV) and the width Γ is 11.8 MeV(25.8 MeV) for K- -3 He(T = 0)(K- -4 He(T= 1/2)).
Mitroy, J.; Bromley, M. W. J.
2006-01-01
The existence of a second bound state of PsH that is electronically stable and also stable against positron annihilation by the normal 2gamma and 3gamma processes is demonstrated by explicit calculation. The state can be found in the 2,4So symmetries with the two electrons in a spin triplet state. The binding energy against dissociation into the H(2p) + Ps(2p) channel was 6.06x10-4 Hartree. The dominant decay mode of the states will be radiative decay into a configuration that autoionizes or ...
Quarks as quasiparticles of bound states
International Nuclear Information System (INIS)
A treatment of quarks as strongly bound subsystems of the baryon structure is considered, with the baryons assigned to various states with integers G and B. The requirement that the appropriate fractional values of the quantum numbers of the quarks be obtained, and that appropriate integral values be obtained for the whole system of three bound quarks, uniquely determine the three initial states of the quarks, labeled by the set of values of the quantum numbers G, B, and J. In this connection the new color quantum number is interpreted as a quantity which characterizes the presence of the subsystems in different eigenstates. The self- consistency of the changes of color states in the three-quark system is explained on the basis of a generalized Sakata model. (author)
Energy Technology Data Exchange (ETDEWEB)
Gotta, Detlev, E-mail: d.gotta@fz-juelich.de [Forschungszentrum Juelich GmbH and JHCP (Germany); Amaro, F. D. [Coimbra University, Department of Physics (Portugal); Anagnostopoulos, D. F. [University of Ioannina, Department of Materials Science and Engineering (Greece); Buehler, P. [Austrian Academy of Sciences, SMI (Austria); Gorke, H. [Forschungszentrum Juelich GmbH and JHCP (Germany); Covita, D. S. [Coimbra University, Department of Physics (Portugal); Fuhrmann, H.; Gruber, A. [Austrian Academy of Sciences, SMI (Austria); Hennebach, M. [Forschungszentrum Juelich GmbH and JHCP (Germany); Hirtl, A.; Ishiwatari, T. [Austrian Academy of Sciences, SMI (Austria); Indelicato, P.; Bigot, E.-O. Le [LKB, UPMC-Paris 6, ENS, CNRS, Case 74 (France); Marton, J. [Austrian Academy of Sciences, SMI (Austria); Nekipelov, M. [Forschungszentrum Juelich GmbH and JHCP (Germany); Santos, J. M. F. dos [Coimbra University, Department of Physics (Portugal); Schlesser, S. [LKB, UPMC-Paris 6, ENS, CNRS, Case 74 (France); Schmid, Ph. [Austrian Academy of Sciences, SMI (Austria); Simons, L. M. [Paul Scherrer Institut (PSI) (Switzerland); Strauch, Th. [Forschungszentrum Juelich GmbH and JHCP (Germany); and others
2012-05-15
The ground-state level shifts and broadenings of the hydrogen isotopes caused by the strong interaction have been redetermined by using a high-resolution crystal spectrometer. An additional measurement of muonic hydrogen reveals properties of the de-excitation cascade of such electrically neutral exotic atoms, in particular Coulomb de-excitation, the understanding of which is essential for the analysis of the hadronic-atom data.
Pionic background for nucleon-nucleon observables
International Nuclear Information System (INIS)
A method is presented that allows the unambiguous definition of the one pion exchange contribution to nucleon-nucleon scattering observables and then use it to determine those waves where values of phase shifts and mixing parameters may be understood as sums of pionic and non-pionic dynamical effects. This helps the assessment of the explicative power of the various existing phenomenological potentials and may eventually lead to ways of discriminating their effectiveness. (author) 16 refs.; 19 figs.; 2 tabs
Topological edge states of bound photon pairs
Gorlach, Maxim A
2016-01-01
We predict the existence of interaction-driven edge states of bound two-photon quasiparticles in a dimer periodic array of nonlinear optical cavities. Energy spectrum of photon pairs is dramatically richer than in the noninteracting case or in a simple lattice, featuring collapse and revival of multiple edge and bulk modes as well as edge states in continuum. Despite the unexpected breakdown of the Zak phase technique and the edge mixing of internal and center-of-mass motion we link the edge state existence to the two-photon quantum walk graph connectivity, thus uncovering the topological nature of the many-body problem in complex lattices.
Analytic continuation of bound states to solve resonance states
Energy Technology Data Exchange (ETDEWEB)
Tanaka, Norimichi; Arai, Koji [Niigata Univ. (Japan); Suzuki, Yoshiyuki; Varga, K.
1997-05-01
As a method to determine the parameters of the resonance state, a method is proposed using analytic continuation on bound constants of correlation. The characteristics of this method consists in probability of prediction of the parameters of the resonance state only by calculation of the bound state. Owing to conducting the analytic continuation on square root of energy in the bound state as a function relating to the bound constant, energy and width in the bound state was determined. Here was reported on a result of application of this method to three systems. Some partial wave on two systems showing correlation at a simple potential and a resonance state of zero of all orbital angular motion quality in three boson system were determined using the analytic continuation method. These results agreed well with one used a method of integrating Schroedinger equation directly and one used the complex scaling method, and this method was found to be much efficient for the study of the resonance state. Under a background of becoming applicable to the method of analytic continuation, there was development of calculating method for the recent small number multi system. As the characteristics of the analytic continuation method is used for only calculation of the bound state, it is convenient at a point applicable to the method to obtain conventional bound state and then is much efficient in a point of applicability of calculus of variations. However, in order to obtain coefficient of Pade approximation correctly, the bound state must be solved correctly, which is difficult for more complex system and is not always applicable to every systems. (G.K.)
Tsirelson's bound and supersymmetric entangled states
Borsten, L; Duff, M J
2012-01-01
In order to see whether superqubits are more nonlocal than ordinary qubits, we construct a class of two-superqubit entangled states as a nonlocal 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 (3) Modified Rogers. In cases (1) and (2) the winning probability reaches the Tsirelson bound p(win) = cos^2 pi/8 \\simeq 0.8536 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.
Quantum Bound States Around Black Holes
Grain, J.; Barrau, A.
2007-01-01
Quantum mechanics around black holes has shown to be one of the most fascinating fields of theoretical physics. It involves both general relativity and particle physics, opening new eras to establish the principles of unified theories. In this article, we show that quantum bound states with no classical equivalent -- as it can easily be seen at the dominant monopolar order -- should be formed around black holes for massive scalar particles. We qualitatively investigate some important physical...
Closed form bound-state perturbation theory
Directory of Open Access Journals (Sweden)
Ollie J. Rose
1980-01-01
Full Text Available The perturbed Schrödinger eigenvalue problem for bound states is cast into integral form using Green's Functions. A systematic algorithm is developed and applied to the resulting equation giving rise to approximate solutions expressed as functions of the given perturbation parameter. As a by-product, convergence radii for the traditional Rayleigh-Schrödinger and Brillouin-Wigner perturbation theories emerge in a natural way.
Weakly bound states in heterogeneous waveguides
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.
Semirelativistic Bound-State Equations: Trivial Considerations
Directory of Open Access Journals (Sweden)
Lucha Wolfgang
2014-01-01
Full Text Available Observing renewed interest in long-standing (semi- relativistic descriptions of two-body bound states, we would like to make a few comments on the eigenvalue problem posed by the spinless Salpeter equation and, illustrated by the examples of the nonsingular Woods–Saxon potential and the singular Hulthén potential, recall elementary tools that, in their quest, practitioners looking for analytic albeit approximate solutions will find useful.
Andreev bound states. Some quasiclassical reflections
International Nuclear Information System (INIS)
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
Andreev bound states. Some quasiclassical reflections
Energy Technology Data Exchange (ETDEWEB)
Lin, Y., E-mail: yiriolin@illinois.edu; Leggett, A. J. [University of Illinois at Urhana-Champaign, Dept. of Physics (United States)
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.
Unexpected strong attraction in the presence of continuum bound state
International Nuclear Information System (INIS)
The result of few-particle ground-state calculation employing a two-particle non-local potential supporting a continuum bound state in addition to a negative-energy bound state has occasionally revealed unexpected large attraction in producing a very strongly bound ground state. In the presence of the continuum bound state the difference of phase shift between zero and infinite energies has an extra jump of φ as in the presence of an additional bound state. The wave function of the continuum bound state is identical with that of a strongly bound negative-energy state, which leads us to postulate a pseudo bound state in the two-particle system in order to explain the unexpected attraction. The role of the Pauli forbidden states is expected to be similar to these pseudo states. (author)
Bound states -- from QED to QCD
Hoyer, Paul
2014-01-01
These lectures are divided into two parts. In Part 1 I discuss bound state topics at the level of a basic course in field theory: The derivation of the Schr\\"odinger and Dirac equations from the QED Lagrangian, by summing Feynman diagrams and in a Hamiltonian framework. Less well known topics include the equal-time wave function of Positronium in motion and the properties of the Dirac wave function for a linear potential. The presentation emphasizes physical aspects and provides the framework...
Is there an quasi-bound state?
Wilkin, C; Chiladze, D; Dymov, S; Hanhart, C; Hartmann, M; Hejny, V; Kacharava, A K; Keshelashvili, I; Khoukaz, A; Maeda, Y; Mersmann, T; Mielke, M; Mikirtychiants, S; Papenbrock, M; Rathmann, F; Rausmann, T; Schleichert, R; Ströher, H; Täschner, A; Valdau, Yu; Wronska, A
2007-01-01
The observed variation of the total cross section for the dp -> 3He eta reaction near threshold means that the magnitude of the s--wave amplitude falls very rapidly with the eta centre--of--mass momentum. It is shown here that recent measurements of the momentum dependence of the angular distribution imply a strong variation also in the phase of this amplitude. Such a behaviour is that expected from a quasi--bound or virtual eta-3He state. The interpretation can be investigated further through measurements of the deuteron or proton analysing powers and/or spin--correlations.
A balance for Dark Matter bound states
Nozzoli, F.
2016-01-01
Massive particles with self interactions of the order of 0.2 barn/GeV are intriguing Dark Matter candidates from an astrophysical point of view. Direct detection searches for very massive particles, with relatively high cross sections with ordinary matter, cannot rule out $\\sigma/M > 0.01$ barn/GeV, due to atmosphere and material shielding. Here, the possibility of the existence of bound states with ordinary matter, for Dark Matter candidates with not negligible interactions, is considered. T...
Novel Bound States in Graphene with Impurities
Gupta, Kumar S
2008-01-01
We obtain a novel bound state spectrum of the low energy excitations near the Fermi points of graphene in the presence of a charge impurity. The effects of possible short range interactions induced by the impurity are modelled by suitable boundary conditions. The spectrum in the subcritical region of the effective Coulomb coupling is labelled by a parameter which characterizes the boundary conditions and determines the inequivalent quantizations of the system. In the supercritical region we obtain a renormalization group flow for the effective Coulomb coupling.
Method for laser spectroscopy of metastable pionic helium atoms
International Nuclear Information System (INIS)
The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic helium atoms using the high-intensity π− beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a helium nucleus, a π− occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic helium atoms at CERN
On Aharonov-Casher bound states
Energy Technology Data Exchange (ETDEWEB)
Silva, E.O. [Universidade Federal do Maranhao, Departamento de Fisica, Sao Luis, MA (Brazil); Andrade, F.M. [Universidade Estadual de Ponta Grossa, Departamento de Matematica e Estatistica, Ponta Grossa, PR (Brazil); Filgueiras, C. [Universidade Federal de Campina Grande, Departamento de Fisica, Caixa Postal 10071, Campina Grande, PB (Brazil); Belich, H. [Universidade Federal do Espirito Santo, Departamento de Fisica e Quimica, Vitoria, ES (Brazil)
2013-04-15
In this work bound states for the Aharonov-Casher problem are considered. According to Hagen's work on the exact equivalence between spin-1/2 Aharonov-Bohm and Aharonov-Casher effects, is known that the {nabla}.E term cannot be neglected in the Hamiltonian if the spin of particle is considered. This term leads to the existence of a singular potential at the origin. By modeling the problem by boundary conditions at the origin which arises by the self-adjoint extension of the Hamiltonian, we derive for the first time an expression for the bound state energy of the Aharonov-Casher problem. As an application, we consider the Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the expression for the harmonic oscillator energies and compare it with the expression obtained in the case without singularity. At the end, an approach for determination of the self-adjoint extension parameter is given. In our approach, the parameter is obtained essentially in terms of physics of the problem. (orig.)
Hadron QCD (Bound states in gauge theories)
International Nuclear Information System (INIS)
The general principles of the description of bound states in QED and QCD are proposed for the aim of construction of the consistent scheme of calculating hadron spectrum and interaction amplitudes. Such principles are the explicit solution of the Gauss equation for time component, the quantization of the minimal set physical variables and the choice of the time-axis of quantization in accordance with the Markov-Yukawa relativistic theory of bilocal fields. QCD constructed by these principles contains new infrared divergences, changing the behaviour of the Coulomb field on large distances. This divergences (like ones in QED) are removed out with the help of phenomenology, in this case, by taking into account the rising potential as the 'nonperturbative background' for a new perturbation theory. It is shown how in such hadron theory the parton model, nonrelativistic potential spectroscopy, chiral Lagrangian and confinement appear. The Dirac quantization method, renormalization group equations and lattice calculations in their conventional formulation are proved to be untenable for the description of bound states. 23 refs
ADMonium: Asymmetric Dark Matter Bound State
Bi, Xiao-Jun; Ko, P; Li, Jinmian; Li, Tianjun
2016-01-01
We propose a novel framework for asymmetric scalar dark matter (ADM), which has interesting collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local $U(1)_d$ symmetry which is broken at a low scale and provides a light gauge boson $X$. The dark gauge coupling is strong and then ADM can annihilate away into $X$-pair effectively. Therefore, the ADM can form bound state due to its large self-interaction via $X$ mediation. To explore the collider signature of ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can have a sizable mixing with the heavier Higgs boson, which admits a large cross section of ADMonium production associated with $b\\bar b$. Of particular interest, our setup nicely explains the recent di-photon anomaly at 750 GeV via the events from ${\\rm ADMonium}\\ra 2X(\\ra e^+e^-)$, where the electrons are identified as ...
Bound states -- from QED to QCD
Hoyer, Paul
2014-01-01
These lectures are divided into two parts. In Part 1 I discuss bound state topics at the level of a basic course in field theory: The derivation of the Schr\\"odinger and Dirac equations from the QED Lagrangian, by summing Feynman diagrams and in a Hamiltonian framework. Less well known topics include the equal-time wave function of Positronium in motion and the properties of the Dirac wave function for a linear potential. The presentation emphasizes physical aspects and provides the framework for Part 2, which discusses the derivation of relativistic bound states at Born level in QED and QCD. A central aspect is the maintenance of Poincar\\'e invariance. The transformation of the wave function under boosts is studied in detail in D=1+1 dimensions, and its generalization to D=3+1 is indicated. Solving Gauss' law for $A^0$ with a non-vanishing boundary condition leads to a linear potential for QCD mesons, and an analogous confining potential for baryons.
A balance for Dark Matter bound states
Nozzoli, F
2016-01-01
Massive particles with self interactions of the order of 0.2 barn/GeV are intriguing Dark Matter candidates from an astrophysical point of view. Direct detection searches for very massive particles, with relatively high cross sections with ordinary matter, cannot rule out $\\sigma/M > 0.01$ barn/GeV, due to atmosphere and material shielding. Here, the possibility of the existence of bound states with ordinary matter, for Dark Matter candidates with not negligible interactions, is considered. The existence of bound states, with binding energy larger than $\\sim$1 meV, would offer the possibility to test in laboratory capture cross sections of the order of a barn (or larger). The signature of the detection of a mass increasing of cryogenic samples, due to the possible Dark Matter accumulation, would allow the investigation of Dark Matter particles with mass up to the GUT scale. A proof of concept for a possible detection set-up and the evaluation of some noise sources are described.
Exact Entanglement Cost of Multi-Qubit Bound Entangled States
Bandyopadhyay, Somshubhro; Roychowdhury, Vwani P.
2005-01-01
We report the exact entanglement cost of a class of multiqubit bound entangled states, computed in the context of a universal model for multipartite state preparation. The exact amount of entanglement needed to prepare such states are determined by first obtaining lower bounds using a cut-set approach, and then providing explicit local protocols achieving the lower bound.
Energy Technology Data Exchange (ETDEWEB)
Bakalov, Dimitar, E-mail: dbakalov@inrne.bas.bg [Bulgarian Academy of Sciences, INRNE (Bulgaria)
2015-08-15
The potential energy surface and the computational codes, developed for the evaluation of the density shift and broadening of the spectral lines of laser-induced transitions from metastable states of antiprotonic helium, fail to produce convergent results in the case of pionic helium. We briefly analyze the encountered computational problems and outline possible solutions of the problems.
Bound states and Lorentz-Poincare symmetry
International Nuclear Information System (INIS)
A hypothesis of the ''relation-continuum'' C is put forward, closely connected with isolation of physical system, which extends to finite universal constant c the absolute nature of the Galilean relative coordinates and the absolute Newtonian time. Points of C4 continuum are directly unobservable and the relativistic symmetry L4 of directly observable space-time events becomes the limiting case of the C4-symmetry. Consequently, though the possibility of the hypothesis of C4-continuum is due to quantum physics, the modifications it implies come with finite universal constant (h/2π)/c and concern the description of the internal structure of bound states only. The C4-symmetry of relations, as weaker than the Lorentz-Poincare L4-symmetry of events, makes ''more room'' for quantum dynamical models. The Feynman graphs phenomenology with form factors (vertex functions) of non-point particles left for experimental determination can be connected with the C4-framework which determines their analytic structure. The C4-effects then would reveal themselves only in these processes in which composite particles participate. Therefore, the ''good'' quantum electrodynamics of point-particles is left unmodified. Two off-mass-shell effects are analyzed in the relatively low-energy processes which are connected with the mass-dependent localization of the center-of-mass of composite particle ''M''. They seem to be crucial for the hypothesis itself. (author)
Squashed giants: bound states of giant gravitons
International Nuclear Information System (INIS)
We consider giant gravitons in the maximally supersymmetric type IIB plane-wave, in the presence of a constant NSNS B-field background. We show that in response to the background B-field the giant graviton would take the shape of a deformed three-sphere, the size and shape of which depend on the B-field, and that the giant becomes classically unstable once the B-field is larger than a critical value Bcr. In particular, for the B-field which is (anti-)self-dual under the SO(4) isometry of the original giant S3, the closed string metric is that of a round S3, while the open string metric is a squashed three-sphere. The squashed giant can be interpreted as a bound state of a spherical three-brane and circular D-strings. We work out the spectrum of geometric fluctuations of the squashed giant and study its stability. We also comment on the gauge theory which lives on the brane (which is generically a noncommutative theory) and a possible dual gauge theory description of the deformed giant. (author)
Real weights, bound states and duality orbits
Marrani, Alessio; Romano, Luca
2015-01-01
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 non-compact and there...
Real weights, bound states and duality orbits
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.
Effects of Bound States on Dark Matter Annihilation
An, Haipeng; Wise, Mark B.; Zhang, Yue
2016-01-01
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 non-trivial 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 rat...
Effects of Bound States on Dark Matter Annihilation
An, Haipeng; Wise, Mark B.; Zhang, Yue
2016-01-01
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 non-trivial 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 ...
Microscopic observation of magnon bound states and their dynamics
Fukuhara, Takeshi; Schauß, Peter; Endres, Manuel; Hild, Sebastian; Cheneau, Marc; Bloch, Immanuel; Gross, Christian
2013-01-01
More than eighty years ago, H. Bethe pointed out the existence of bound states of elementary spin waves in one-dimensional quantum magnets. To date, identifying signatures of such magnon bound states has remained a subject of intense theoretical research while their detection has proved challenging for experiments. Ultracold atoms offer an ideal setting to reveal such bound states by tracking the spin dynamics after a local quantum quench with single-spin and single-site resolution. Here we r...
Precision Study of Positronium: Testing Bound State QED Theory
Karshenboim, Savely G.
2003-01-01
As an unstable light pure leptonic system, positronium is a very specific probe atom to test bound state QED. In contrast to ordinary QED for free leptons, the bound state QED theory is not so well understood and bound state approaches deserve highly accurate tests. We present a brief overview of precision studies of positronium paying special attention to uncertainties of theory as well as comparison of theory and experiment. We also consider in detail advantages and disadvantages of positro...
Dark-matter bound states from Feynman diagrams
K. Petraki; M. Postma; M. Wiechers
2015-01-01
If dark matter couples directly to a light force mediator, then it may form bound states in the early universe and in the non-relativistic environment of haloes today. In this work, we establish a field-theoretic framework for the computation of bound-state formation cross-sections, de-excitation an
Bound states in a hyperbolic asymmetric double-well
Energy Technology Data Exchange (ETDEWEB)
Hartmann, R. R., E-mail: richard.hartmann@dlsu.edu.ph [Physics Department, De La Salle University, 2401 Taft Avenue, Manila (Philippines)
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.
Tauonium tau+tau-, a bound state of heavy leptons
International Nuclear Information System (INIS)
Some properties of an electromagnetically bound state of the recently discovered tau heavy lepton are analyzed. This bound state of tau+tau-, has been called tauonium, T. It is found that the process e+e-→T→X has a very high cross section but that it might have escaped observation because of the very narrow width of the T
The representation of bound state wavefunctions by spherical Hankel functions
International Nuclear Information System (INIS)
The representation of a nucleon bound state by a single Hankel function is generalised such that the bound state is expanded as a linear combination of Hankel functions of the same l-value. The singularity at the origin due to the use of Hankel functions is removed. The arguments and coefficients of the expansion are determined by a variational method. (orig.)
International Nuclear Information System (INIS)
Pionic X-ray energies, lorentzian widths, and relative intensities have been measured for the transitions in liquid 3He. The pion-nucleus interaction is found to result in an attractive shift of the 1s level of 27 +- 5 eV and in a lorentzian width of 65 +- 12 eV. The measured Ksub(β) to Ksub(α) intensity ratio is 1.05 +- 0.07. (Auth.)
The Pionic Hydrogen Experiment at PSI
Energy Technology Data Exchange (ETDEWEB)
Anagnostopoulos, D. F. [University of Ioannina, Department of Material Science (Greece); Biri, S. [Hungarian Academy of Science, Institut of Nuclear Research (Hungary); Borchert, G. [Forschungszentrum Juelich, Institut fuer Kernphysik (Germany); Breunlich, W.; Cargnelli, M. [Osterreichische Akademie der Wissenschaften, Institut fuer Mittelenergiephysik (Austria); Egger, J.-P. [Universite de Neuchatel, Institut de Physique (Switzerland); Fuhrmann, H. [Osterreichische Akademie der Wissenschaften, Institut fuer Mittelenergiephysik (Austria); Gotta, D., E-mail: d.gotta@fz-juelich.de [Forschungszentrum Juelich, Institut fuer Kernphysik (Germany); Giersch, M.; Gruber, A. [Osterreichische Akademie der Wissenschaften, Institut fuer Mittelenergiephysik (Austria); Hennebach, M. [Forschungszentrum Juelich, Institut fuer Kernphysik (Germany); Indelicato, P. [Universite Pierre et Marie Curie, Laboratoire Kastler-Brossel (France); Jensen, T. S. [Institut fuer Theoretische Physik (Switzerland); Kottmann, F. [ETHZ, Institut fuer Teilchenphysik (Switzerland); Liu, Y.-W. [Paul-Scherrer-Institut (PSI) (Switzerland); Manil, B. [Universite Pierre et Marie Curie, Laboratoire Kastler-Brossel (France); Markushin, V. M. [Paul-Scherrer-Institut (PSI) (Switzerland); Marton, J. [Osterreichische Akademie der Wissenschaften, Institut fuer Mittelenergiephysik (Austria); Nelms, N. [University of Leicester, Department of Physics and Astronomy (United Kingdom); Oades, G. C. [Aarhus University, Institute of Physics (Denmark)
2001-12-15
The measurement of the strong-interaction effects in pionic hydrogen gives access to fundamental properties of the pion-nucleon interaction. Methods developed within the framework of Heavy-Baryon Chiral Perturbation Theory allow calculations with an accuracy of a few per cent, which should be tested by experiment.Techniques advanced for recent experiments on the precision spectroscopy of X-rays from antiprotonic and pionic atoms will be used in a new series of measurements for pionic hydrogen. The aim is to achieve finally an accuracy of 0.2% for the hadronic shift element of {sub 1s} and most important of about 1% for the broadening {Gamma}{sub 1s}.An essential part of the experimental program is an improved understanding of the atomic cascade. At first, the value of element of {sub 1s} has to be proven not to be influenced by molecular formation. Secondly, a more accurate determination of {Gamma}{sub 1s} requires a detailed study of Coulomb deexcitation.
Asymptotic properties of bound states in coupled quantum wave guides
Energy Technology Data Exchange (ETDEWEB)
Maglione, Enrico [Dipartimento di Fisica G Galilei, Via F Marzolo 8, Padova (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova (Italy); Centro de Fisica das Interaccoes Fundamentais (CFIF), Avenida Rovisco Pais, Lisbon (Portugal); Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais, P1049-001 Lisbon (Portugal); Ferreira, LIdia S [Centro de Fisica das Interaccoes Fundamentais (CFIF), Avenida Rovisco Pais, Lisbon (Portugal); Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais, P1049-001 Lisbon (Portugal); Cattapan, Giorgio [Dipartimento di Fisica G Galilei, Via F Marzolo 8, Padova (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova (Italy)
2006-02-03
We investigate the motion of bound-state poles in two quantum wave guides laterally coupled through a window. The imaginary momentum ik at the bound-state poles is studied as a function of the size a of the window. Both bound and virtual states appear as a spans the whole range from 0 up to +{infinity}. We are able to find simple scaling laws relating the critical value of the window size at which the nth bound state appears to the number n of bound states, in the limit of large n. A similar relation is also provided for the slope and the second derivative of the pole trajectories in the (k, a) plane. These relations are characterized by an extremely high numerical accuracy. We also evaluate the exact value of the first two derivatives for a = 0.
Recent advances in bound state quantum electrodynamics
International Nuclear Information System (INIS)
Recent developments are reviewed in four areas of computational quantum electrodynamics: a new relativistic two-body formalism equal in rigor to the Bethe-Salpeter formalism but with strong calculational advantages is discussed; recent work on the computation of the decay rate of bound systems (positronium in particular) is presented; limits on possible composite structure of leptons are discussed; a new multidimensional integration program ('VEGAS') suitable for higher order calculations is presented
Weakly bound states of polar molecules in bilayers
Fedorov, D V; Zinner, N T; Jensen, A S
2011-01-01
We investigate a system of two polarized molecules in a layered trap. The molecules reside in adjacent layers and interact purely via the dipole-dipole interaction. We determine the properties of the ground state of the system as a function of the dipole moment and polarization angle. A bound state is always present in the system and in the weak binding limit the bound state extends to a very large distance and shows universal behavior.
Relativistic bound states: a mass formula for vector mesons
International Nuclear Information System (INIS)
In the framework of a relativistic description of two particles bound states, a mass formula for vector mesons considered as quark-antiquark systems bound by harmonic oscillator like forces is proposed. Results in good agreement with experimental values are obtained
Higgs interchange and bound states of superheavy fermions
Indian Academy of Sciences (India)
M De Sanctis
2013-09-01
Hypothetical superheavy fourth-generation fermions with a very small coupling with the rest of the Standard Model can give rise to long enough lived bound states. The production and the detection of these bound states would be experimentally feasible at the LHC. Extending, in the present study, the analysis of other authors, a semirelativistic wave equation is solved using an accurate numerical method to determine the binding energies of these possible superheavy fermion-bound states. The interaction given by the Yukawa potential of the Higgs boson exchange is considered; the corresponding relativistic corrections are calculated by means of a model based on the covariance properties of the Hamiltonian. We study the effects given by the Coulomb force. Moreover, we calculate the contributions given by the Coulombic and confining terms of the strong interaction in the case of superheavy quark bound states. The results of the model are critically analysed.
Transport Through Andreev Bound States in a Graphene Quantum Dot
Dirks, Travis; Hughes, Taylor L.; Lal, Siddhartha; Uchoa, Bruno; Chen, Yung-Fu; Chialvo, Cesar; Goldbart, Paul M.; Mason, Nadya
2010-01-01
Andreev reflection-where an electron in a normal metal backscatters off a superconductor into a hole-forms the basis of low energy transport through superconducting junctions. Andreev reflection in confined regions gives rise to discrete Andreev bound states (ABS), which can carry a supercurrent and have recently been proposed as the basis of qubits [1-3]. Although signatures of Andreev reflection and bound states in conductance have been widely reported [4], it has been difficult to directly...
Bound States of a Ferromagnetic Wire in a Superconductor
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.
Bound States of a Ferromagnetic Wire in a Superconductor.
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
Pionic-decay spectra of few-body Λ-hypernuclei
International Nuclear Information System (INIS)
Pionic-decay spectra are discussed in A=4 and 5 Λ-hypernuclei by using wave-functions obtained by the resonating group method. For Λ5He, the π--spectrum shows a sharp peak at 171 MeV with 1.5 MeV FWHM in the total pion energy. For Λ4H and Λ4He, the spectra have broad peaks around 170 MeV with 6-7 MeV FWHM. This difference is caused by resonance structures of the final-state nuclei under the spin-non-flip dominance in the pionic decay. The calculated partial decay widths are in systematically good agreement with all available experimental data. (author)
Graphene in inhomogeneous magnetic fields: bound, quasi-bound and scattering states
Energy Technology Data Exchange (ETDEWEB)
Ramezani Masir, M; Peeters, F M [Departement Fysica, Universiteit Antwerpen Groenenborgerlaan 171, B-2020 Antwerpen (Belgium); Vasilopoulos, P, E-mail: mrmphys@gmail.com, E-mail: takis@alcor.concordia.ca, E-mail: francois.peeters@ua.ac.be [Department of Physics, Concordia University, Montreal, Quebec, H4B 1R6 (Canada)
2011-08-10
The electron states in graphene-based magnetic dot and magnetic ring structures and combinations of both are investigated. The corresponding spectra are studied as a function of the radii, the strengths of the inhomogeneous magnetic field and of a uniform background field, the strength of an electrostatic barrier and the angular momentum quantum number. In the absence of an external magnetic field we have only long-lived quasi-bound and scattering states and we assess their influence on the density of states. In addition, we consider elastic electron scattering by a magnetic dot, whose average B vanishes, and show that the Hall and longitudinal resistivities, as a function of the Fermi energy, exhibit a pronounced oscillatory structure due to the presence of quasi-bound states. Depending on the dot parameters this oscillatory structure differs substantially for energies below and above the first Landau level.
Boson bound states in the -Fermi–Pasta–Ulam model
Indian Academy of Sciences (India)
Xin-Guang Hu; Ju Xiang; Zheng Jiao; Yang Liu; Guo-Qiu Xie; Ke Hu
2013-11-01
The bound states of four bosons in the quantum -Fermi–Pasta–Ulam model are investigated and some interesting results are presented using the number conserving approximation combined with the number state method. We find that the relative magnitude of anharmonic coefficient has a significant effect on forming localized energy in the model, and the wave number plays an important role in forming different bound states. The signature of the quantum breather is also set up by the square of the amplitudes of the corresponding eigenvectors in real space.
Effects of Bound States on Dark Matter Annihilation
An, Haipeng; Zhang, Yue
2016-01-01
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 non-trivial 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.
Proximity induced interface bound states in superconductor-graphene junctions
Burset, P.; Herrera, W.; Yeyati, A. Levy
2009-01-01
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...
Supergiant halos as an integral record of natural pionic radioactivity
Ion, D. B.; Ion-Mihai, Reveica; Ion, M. L.; Sandru, Adriana I.
2004-01-01
In this paper an unified interpretation of the supergiant halos (SGH), discovered by Grady, Walker and Laemmlein, is discussed. So, it is proved that SGH`s can be considered as integral records of the nuclear pionic radioactivity.
Probing Majorana Bound States in T-Shaped Junctions
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.
Relativistic bound state approach to fundamental forces including gravitation
Directory of Open Access Journals (Sweden)
Morsch H.P.
2012-06-01
Full Text Available To describe the structure of particle bound states of nature, a relativistic bound state formalism is presented, which requires a Lagrangian including scalar coupling of two boson fields. The underlying mechanisms are quite complex and require an interplay of overlapping boson fields and fermion-antifermion production. This gives rise to two potentials, a boson-exchange potential and one identified with the long sought confinement potential in hadrons. With minimal requirements, two elementary massless fermions (quantons - with and without charge - and one gauge boson, hadrons and leptons but also atoms and gravitational systems are described by bound states with electric and magnetic coupling between the charges and spins of quantons. No need is found for colour, Higgs-coupling and supersymmetry.
A brief review on Majorana bound states in topological superconductors
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.
Bound States at Threshold resulting from Coulomb Repulsion
Gridnev, Dmitry K
2011-01-01
The eigenvalue absorption for a many-particle Hamiltonian depending on a parameter is analyzed in the framework of non-relativistic quantum mechanics. The long-range part of pair potentials is assumed to be pure Coulomb and no restriction on the particle statistics is imposed. It is proved that if the lowest dissociation threshold corresponds to the decay into two likewise non-zero charged clusters then the bound state, which approaches the threshold, does not spread and eventually becomes the bound state at threshold. The obtained results have applications in atomic and nuclear physics. In particular, we prove that atomic ion with atomic critical charge $Z_{cr}$ and $N_e$ electrons has a bound state at threshold given that $Z_{cr} \\in (N_e -2, N_e -1)$, whereby the electrons are treated as fermions and the mass of the nucleus is finite.
Question of η- and K−- Nucleus Bound States
International Nuclear Information System (INIS)
Interaction of the η-meson and that of the K−-meson with nucleons is of special interest because both of them are strongly attractive near threshold. This raises the strong possibility that we may find in nature the bound η- and K−-nuclear (quasi) bound states. This led to experimental programs to hunt for the existence of these states and theoretical studies to keep pace with them. The efforts had positive results. The η-meson studies had been there for several years by now, while those with the K−-meson had been relatively recent. The talk gives a brief critical overview of the η-nuclear interaction studies, especially in context with the η-mesic state explorations. For the K−-meson we give a brief summary of the efforts in understanding the basic K−-nucleon interaction and theoretical explorations for the existence of K−-nucleus bound states. We critically examine the FINUDA measurements as a signal for the existence of the K−-nucleus bound states, especially in context with the contribution of the single nucleon knock-out final state interaction in the (K−, pΛ) reaction.
An Upper Bound of Fully Entangled Fraction of Mixed States
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
A framework for bounding nonlocality of state discrimination
Childs, Andrew M.; Leung, Debbie; Mancinska, Laura; Ozols, Maris
2012-01-01
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" [BDF+99], 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 dis...
Directional detection of dark matter in universal bound states
Energy Technology Data Exchange (ETDEWEB)
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.
On Deusons or Deuteronlike Meson-Meson Bound States
Törnqvist, N A
1994-01-01
The systematics of deuteronlike two-meson bound states, {\\it deusons}, is discussed. Previous arguments that many of the present non-$q\\bar q$ states are such states are elaborated including, in particular, the tensor potential. For pseudoscalar states the important observation is made that the centrifugal barrier from the P-wave can be overcome by the $1/r^2$ and $1/r^3$ terms of the tensor potential. In the heavy meson sector one-pion exchange alone is strong enough to form at least deuteron-like $B\\bar B^*$ and $B^*\\bar B^*$ composites bound by approximately 50 MeV, while $D\\bar D^*$ and $D^*\\bar D^*$ states are expected near the threshold.
A search for unexpected bound states in 15B
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
Towards flavored bound states beyond rainbows and ladders
El-Bennich, B; Paracha, M A; de Melo, J P B C
2013-01-01
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.
Towards flavored bound states beyond rainbows and ladders
Energy Technology Data Exchange (ETDEWEB)
El-Bennich, B.; Rojas, E.; Melo, J. P. B. C. de [Laboratório de Física Teórica e Computacional, Universidade Cruzeiro do Sul, São Paulo 01506-000 SP (Brazil); Paracha, M. A. [Laboratorio de Fisica Teorica e Computacional, Universidade Cruzeiro do Sul, Sao Paulo 01506-000 SP, Brazil and Centre for Advanced Mathematics and Physics, National University of Science and Technology, Islamabad (Pakistan)
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.
Detection of positron-atom bound states through resonant annihilation
Dzuba, V A; Gribakin, G F
2010-01-01
A method is proposed for detecting positron-atom bound states by observing Feshbach resonances in positron annihilation at electron volt energies. The method is applicable to a range of open-shell transition metal atoms which are likely to bind the positron: Si, Fe, Co, Ni, Ge, Tc, Ru, Rh, Sn, Sb, Ta, W, Os, Ir, and Pt.
Bound States and Supercriticality in Graphene-Based Topological Insulators
Directory of Open Access Journals (Sweden)
Reinhold Egger
2013-01-01
Full Text Available We study the bound state spectrum and the conditions for entering a supercritical regime in graphene with strong intrinsic and Rashba spin-orbit interactions within the topological insulator phase. Explicit results are provided for a disk-shaped potential well and for the Coulomb center problem.
In-medium antikaon interactions and bound states
Gal, Avraham; Barnea, Nir; Cieplý, Aleš; Mareš, Jiří; Gazda, Daniel
2014-01-01
Correct treatment of subthreshold Kbar-N dynamics is mandatory in kaonic-atom and Kbar-nuclear bound-state calculations, as demonstrated by using in-medium chirally-based models of Kbar-N interactions. Recent studies of kaonic-atom data reveal appreciable multi-nucleon contributions. Kbar-nuclear widths larger than 50 MeV are anticipated.
Dynamics of deeply bound (K) over-bar states
Czech Academy of Sciences Publication Activity Database
Mareš, Jiří; Friedman, E.; Gal, A.
2007-01-01
Roč. 22, 2-3 (2007), s. 633-636. ISSN 0217-751X R&D Projects: GA AV ČR IAA100480617 Institutional research plan: CEZ:AV0Z10480505 Keywords : over-bar-nuclear bound states * over-bar-nuclear relativistic mean field calculations Subject RIV: BE - Theoretical Physics Impact factor: 0.764, year: 2007
Approximate solution of bound state problems through continued fractions
International Nuclear Information System (INIS)
A method to solve ordinary linear differential equations through continued fractions is applied to several physical systems. In particular, results for the Schroedinger equation give a good accuracy for the eigenvalues of bound states in the S-wave Yukawa potential, and the lowest order approximations provide exact values for the harmonic oscillator and Coulomb potential eigenvalues and eigenfuctions. (orig.)
Effective field theories for non-relativistic bound states
International Nuclear Information System (INIS)
I review some of the progress made in the last ten years in providing a solid foundation to the description of non-relativistic bound states in QED and QCD by means of effective field theories. I will discuss some applications. (author)
K-nuclear bound states in a dynamical model
Czech Academy of Sciences Publication Activity Database
Mareš, Jiří; Friedman, E.; Gal, A.
2006-01-01
Roč. 770, 1/2 (2006), s. 84-105. ISSN 0375-9474 Institutional research plan: CEZ:AV0Z10480505 Keywords : kaonic atoms * K-nuclear bound states * K-nucleus interaction Subject RIV: BE - Theoretical Physics Impact factor: 2.155, year: 2006
Bound states in the continuum in quasiperiodic systems
Energy Technology Data Exchange (ETDEWEB)
Hsueh, W.J., E-mail: hsuehwj@ntu.edu.t [Department of Engineering Science, National Taiwan University, Taipei 10660, Taiwan (China); Chen, C.H.; Chang, C.H. [Department of Engineering Science, National Taiwan University, Taipei 10660, Taiwan (China)
2010-11-01
We first propose the existence of bound states in the continuums (BICs) in quasiperiodic systems. Owing to long-range correlation, destructive interference may occur in quasiperiodic systems with higher generation order. Occurrences of BICs in Fibonacci quantum wells studied by localization analysis and gap map method are proposed.
Polarization control of the bound state of a vector soliton
International Nuclear Information System (INIS)
This article demonstrates that the number of pulses in a group of vector bound solitons can be accurately adjusted by polarization control. We could achieve states with up to seven pulses trapped in a group with equally firm pulse separation. The stable relative phase between pulses within the group is manifested as an interference pattern in the soliton spectrum. (letter)
Bound States in the AdS/CFT Correspondence
Minces, P
2004-01-01
We consider a massive scalar field theory in anti-de Sitter space, in both minimally and non-minimally coupled cases. We introduce a relevant double-trace perturbation at the boundary, by carefully identifying the correct source and generating functional for the corresponding conformal operator. We show that such relevant double-trace perturbation introduces changes in the coefficients in the boundary terms of the action, which in turn govern the existence of a bound state in the bulk. For instance, in the minimally coupled case, we show that the usual action, containing no additional boundary terms, gives rise to a bound state, which can be avoided only through the addition of a proper boundary term. Another notorious example is that of a conformally coupled scalar field, for which there is no associated bound state. In general, in both minimally and non-minimally coupled cases, we explicitly compute the boundary terms which give rise to a bound state, and which ones do not. In the non-minimally coupled case...
Gluon mass generation in the massless bound-state formalism
Ibañez, D
2012-01-01
We present a detailed, all-order study of gluon mass generation within the massless bound-state formalism, which constitutes the general framework for the systematic implementation of the Schwinger mechanism in non-Abelian gauge theories. The main ingredient of this formalism is the dynamical formation of bound-states with vanishing mass, which give rise to effective vertices containing massless poles; these latter vertices, in turn, trigger the Schwinger mechanism, and allow for the gauge-invariant generation of an effective gluon mass. This particular approach has the conceptual advantage of relating the gluon mass directly to quantities that are intrinsic to the bound-state formation itself, such as the "transition amplitude" and the corresponding "bound-state wave-function". As a result, the dynamical evolution of the gluon mass is largely determined by a Bethe-Salpeter equation that controls the dynamics of the relevant wave-function, rather than the Schwinger-Dyson equation of the gluon propagator, as h...
Closed string brane-like states, brane bound states and noncommutative branes
International Nuclear Information System (INIS)
We study the mass and different RR charge distributions of the BPS (p,p-2)-brane bound states in the closed string brane-like σ-model. We show that such brane bound states can be realized by introducing a constant B field in the closed string theory. In addition we show that the worldvolume coordinates of these brane bound states turn out to be noncommutative. (author)
Effective Hamiltonian for bound states in Yukawa theory
International Nuclear Information System (INIS)
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
'Dressing' and bound states in quantum field theory
International Nuclear Information System (INIS)
The program of introducing 'dressed' particles (instead of 'bare' ones) was suggested earlier by L. Faddev et al. It is modified here for the case when 'dressed' states can decay. On the basis of this 'dressing' formalism, a new approach is proposed to the problem of bound states in field theories such as the hydrogen atom and the positronium in QED or hadrons in QCD. Peculiarities of this approach as compared to the known ones are discussed. 22 refs
Observation of bound states in Lieb photonic lattices
Vicencio, Rodrigo A; Morales-Inostroza, Luis; Real, Bastian; Weimann, Steffen; Szameit, Alexander; Molina, Mario I
2014-01-01
We present the first experimental demonstration of a new type of bound states in the continuum, namely, compacton-like linear states in flat bands lattices. To this end, photonic Lieb lattices are employed, which exhibit three tight-binding bands, with one being perfectly flat. Our results could be of great importance for fundamental physics as well as for various applications concerning imaging and data transmission.
International Nuclear Information System (INIS)
We investigate weakly bound dyon-fermion states of the lowest angular momentum. Both Coulomb attraction and Coulomb repulsion are studied. Binding energies are given by a transcendental equation which is solved explicitly in a number of limiting cases.Normalized wave functions are given in terms of Bessel functions and confluent hypergeometric functions. (orig.)
Schwinger functions, light-quark bound states and sigma terms
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.
Bound States in the Continuum in double layer structures
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.
Andreev bound state spectrum in half-metallic ferromagnets
International Nuclear Information System (INIS)
Half-metallic ferromagnets are important for potential applications in spintronics and as sources of completely spin-polarized currents. In heterostructures with superconductors they introduce new effects in the interface regions, like spin-mixing and triplet rotation. A triplet supercurrent trough a half metal has been predicted and experimentally verified. Another interesing question regards the question how the density of states is modified in the half-metallic region. Here we present results of the Andreev bound state spectrum in a half-metal/superconductor proximity structure. We discuss the dependence on the interface parameters that enter the interface scattering matrix of the heterostructure. We discuss the role of odd-frequency pairing amplitudes in the proximity structure. We also study the modification of the Andreev bound state spectrum in a superflow
Shooting quasiparticles from Andreev bound states in a superconducting constriction
Energy Technology Data Exchange (ETDEWEB)
Riwar, R.-P.; Houzet, M.; Meyer, J. S. [University of Grenoble Alpes, INAC-SPSMS (France); Nazarov, Y. V., E-mail: Y.V.Nazarov@tudelft.nl [Delft University of Technology, Kavli Institute of NanoScience (Netherlands)
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.
Are there compact heavy four-quark bound states?
Vijande, Javier; Weissman, E.; Valcarce, A.; Barnea, N.
2007-01-01
We present an exact method to study four-quark systems based on the hyperspherical harmonics formalism. We apply it to several physical systems of interest containing two heavy and two light quarks using different quark-quark potentials. Our conclusions mark the boundaries for the possible existence of compact, nonmolecular, four-quark bound states. While QQ (n) over bar(n) over bar states may be stable in nature, the stability of Q (Q) over barn (n) over bar states would imply the existence ...
A variational study of bound states in the Higgs model
Siringo, F
2000-01-01
The possible existence of Higgs-Higgs bound states in the Higgs sector of the Standard Model is explored using the |hh>+|hhh> variational ansatz of Di Leo and Darewych. The resulting integral equations can be decoupled exactly, yielding a one-dimensional integral equation, solved numerically. We thereby avoid the extra approximations employed by Di Leo and Darewych, and we find a qualitatively different mass renormalization. Within the conventional scenario, where a not-too-large cutoff is invoked to avoid "triviality", we find, as usual, an upperbound on the Higgs mass. Bound-state solutions are only found in the very strong coupling regime, but at the same time a relatively small physical mass is required as a consequence of renormalization.
Observation of Andreev bound states at spin-active interfaces
Energy Technology Data Exchange (ETDEWEB)
Beckmann, Detlef; Wolf, Michael Johannes [KIT, Institut fuer Nanotechnologie (Germany); Huebler, Florian [KIT, Institut fuer Nanotechnologie (Germany); KIT, Institut fuer Festkoerperphysik (Germany); Loehneysen, Hilbert von [KIT, Institut fuer Festkoerperphysik (Germany); KIT, Physikalisches Institut (Germany)
2013-07-01
We report on high-resolution differential conductance experiments on nanoscale superconductor/ferromagnet tunnel junctions with ultra-thin oxide tunnel barriers. We observe subgap conductance features which are symmetric with respect to bias, and shift according to the Zeeman energy with an applied magnetic field. These features can be explained by resonant transport via Andreev bound states induced by spin-active scattering at the interface. From the energy and the Zeeman shift of the bound states, both the magnitude and sign of the spin-dependent interfacial phase shifts between spin-up and spin-down electrons can be determined. These results contribute to the microscopic insight into the triplet proximity effect at spin-active interfaces.
Bound states in coupled guides. II. Three dimensions
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.
Bound States in Minkowski Space in 2 + 1 Dimensions
International Nuclear Information System (INIS)
The Nakanishi perturbative integral representation of the Bethe–Salpeter amplitude in three-dimensions (2 + 1) is used to solve the corresponding homogeneous Bethe–Salpeter equation in Minkowski space. The projection of this equation onto the null-plane, as reported here, leads to a bound-state equation for the Nakanishi weight function. The explicit forms of the integral equation for the Nakanishi weight function are shown in the ladder approximation. In addition, the valence light-front wave function is presented. The formal steps of the formalism are illustrated to some extend, with the resulting equation being applied to a bound state system composed by two identical scalar particles of mass m, interacting through the exchange of another massive scalar particle of mass μ. The results reported in this contribution show quite good agreement between our calculations obtained from the Bethe–Salpeter amplitude with the Nakanishi weight function with direct solutions obtained in the Euclidean space. (author)
Understanding the nucleon as a Borromean bound-state
Directory of Open Access Journals (Sweden)
Jorge Segovia
2015-11-01
Full Text Available Analyses of the three valence-quark bound-state problem in relativistic quantum field theory predict that the nucleon may be understood primarily as a Borromean bound-state, in which binding arises mainly from two separate effects. One originates in non-Abelian facets of QCD that are expressed in the strong running coupling and generate confined but strongly-correlated colour-antitriplet diquark clusters in both the scalar–isoscalar and pseudovector–isotriplet channels. That attraction is magnified by quark exchange associated with diquark breakup and reformation. Diquark clustering is driven by the same mechanism which dynamically breaks chiral symmetry in the Standard Model. It has numerous observable consequences, the complete elucidation of which requires a framework that also simultaneously expresses the running of the coupling and masses in the strong interaction. Planned experiments are capable of validating this picture.
International Nuclear Information System (INIS)
Pionic decays of hadrons are calculated using a PCAC (partial conservation of axial-vector current) prescription and a quark shell model with quarks bound by a central potential, described by the Dirac equation. The Dirac Hamiltonian and operators are expanded in v/c, the internal quark velocity. Then, one finds an exact saturation of the current-algebra sum rules as defined in the SU(2)xSU(2) symmetry of Gilman-Harari and Weinberg up to order v4/c4. The saturation is obtained without need of exotics, with the usual excitations of the ground state. The relation with the P = infinity approach is clarified. The corrections found with respect to previous quark models in L = 2 decays are discussed. They do not solve the problem of SU(6)/sub W/ coupling signs. Finally, the whole Weinberg scheme of linear SU(2)xSU(2) symmetry is completed by the expression of the chiral-breaking part of the mass operator m4/sup ts2/
Bound States in the Continuum in Nuclear and Hadron Physics
Lenske, H; Cao, Xu
2015-01-01
The population of bound states in the continuum and their spectral properties are studied on the nuclear and hadronic scale. The theoretical approach is presented and realizations in nuclear and charmonium spectroscopy are dis- cussed. The universality of the underlying dynamical principles is pointed out. Applications to nuclear systems at the neutron dripline and for charmonium spectroscopy by $e^- e^+ \\to D\\bar{D}$ production are discussed.
Weakly bound states of neutrons in gravitational fields
Khugaev, Avas V.; Sultanov, Renat A.; Guster, Dennis
2010-01-01
In this paper a quantum-mechanical behaviour of neutrons in gravitational fields is considered. A first estimation is made using the semiclassical approximation, neglecting General Relativity, magnetic and rotation effects, for neutrons in weakly bound states in the weak gravitational field of the Earth. This result was generalized for a case, in which the Randall - Sundrum correction to Newton's gravitational law on the small scales was applied. Application of the results to Neutron Star phy...
Approximate bound Dirac states for pseudoscalar Hulthen potential
International Nuclear Information System (INIS)
In this paper, we present approximate analytical solutions of the Dirac equation with the pseudoscalar Hulthen potential under spin and pseudospin (p-spin) symmetry limits in (3+1) dimensions. The energy eigenvalues and corresponding eigenfunctions are given in their closed forms by using the Nikiforov–Uvarov (NU) method. Numerical results of the energy eigenvalue equations are presented to show the effects of the potential parameters on the bound-state energies. (author)
Bound states in weakly deformed waveguides: numerical vs analytical results
Amore, Paolo; Fernández, Francisco M; Jacobo, Martin; Zhevandrov, Petr
2016-01-01
We have studied the emergence of bound states in weakly deformed and/or heterogeneous waveguides, comparing the analytical predictions obtained using a recently developed perturbative method, with precise numerical results, for different configurations (a homogeneous asymmetric waveguide, a heterogenous asymmetric waveguide and a homogeneous broken-strip). In all the examples considered in this paper we have found excellent agreement between analytical and numerical results, thus providing a numerical verification of the analytical approach.
Fermion Bound States Around Skyrmions in Doped Antiferromagnets
Institute of Scientific and Technical Information of China (English)
寇谡鹏
2003-01-01
We show the skyrmion effects in doped antiferromagnets for the uniform flux phase. The low-energy effective theory of the t′-J model can be mapped onto the massive quantum electrodynamics. There exist Fermion bound states around skyrmions. For each sublattice, there exist induced fractional fermion numbers around the skyrmions. The total induced fermion number is zero due to the "cancelling effect" between two sublattices with opposite charges.
Two-body bound states & the Bethe-Salpeter equation
Energy Technology Data Exchange (ETDEWEB)
Pichowsky, M. [Argonne National Lab., IL (United States); Kennedy, M. [Univ. of New Hampshire, Durham, NH (United States). Physics Dept.; Strickland, M. [Duke Univ., Durham, NC (United States)
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.
Upsilon particles as bound states of new heavy quarks
International Nuclear Information System (INIS)
Charmonium spectroscopy (cc) was analysed, recently using a power confining potential and was determined that the energy eigenvalues are in good agreement with experimental values when it was used a power equal to 1/2 (square root potential). Assuming universality of the potential for quark-antiquark (qq) and assuming that the particle γ (9.4 GeV) is the fundamental state of the pair bb (beauty quark). The remaning bound states of this pair and their leptonic and hadronic decay widths are calculated
Three-boson bound states in finite volume with EFT
International Nuclear Information System (INIS)
The universal properties of a three-boson system with large scattering length are well understood within the framework of Effective Field Theory. They include a geometric spectrum of shallow three-body bound states called Efimov states and log-periodic dependence of scattering observables on the scattering length. We investigate the modification of this spectrum in a finite cubic box using a partial wave expansion. The dependence of the binding energies on the box size is calculated and the renormalization of the Effective Field Theory in finite volume is verified explicitly.
Bound states in continuum: Quantum dots in a quantum well
International Nuclear Information System (INIS)
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.
Analytic continuation as a bridge between continuum and bound states
Directory of Open Access Journals (Sweden)
Blokhintsev Leonid
2015-01-01
Full Text Available 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.
Photo-production of Bound States with Hidden Charms
Wu, Jia-Jun
2012-01-01
The photo-production of $J/\\Psi$-$^3He$ bound state ($[^3He]_{J/\\Psi}$) on a $^4He$ target has been investigated using the impulse approximation. The calculations have been performed using several $\\gamma+N \\rightarrow J/\\Psi +N$ models based on the Pomeron-exchange and accounting for the pion-exchange mechanism at low energies. The $J/\\Psi$ wavefunctions in $[^3He]_{J/\\Psi}$ are generated from various $J/\\Psi$-nucleus potentials which are constructed by either using a procedure based on the Pomeron-quark coupling mechanism or folding a $J/\\Psi$-N potential ($v_{J/\\Psi,N}$) into the nuclear densities. We consider $v_{J/\\Psi,N}$ derived from the effective field theory approach, Lattice QCD, and Pomeron-quark coupling mechanism. The upper bound of the predicted total cross sections is about $0.1 - 0.3$ pico-barn. We also consider the possibility of photo-production of a six quark-$J/\\Psi$ bound state ($[q^6]_{J/\\Psi})$ on the $^3He$ target. The Compound Bag Model of $NN$ scattering and the quark cluster model o...
Accurate calculations of bound rovibrational states for argon trimer
Energy Technology Data Exchange (ETDEWEB)
Brandon, Drew; Poirier, Bill [Department of Chemistry and Biochemistry, and Department of Physics, Texas Tech University, Box 41061, Lubbock, Texas 79409-1061 (United States)
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.
Accurate calculations of bound rovibrational states for argon trimer
International Nuclear Information System (INIS)
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
Colour-octet bound states, induced by Higgs mechanism
Bladwell, S; Flambaum, V V; Kozlov, A
2012-01-01
The current limits for fourth generation quarks allows to expect their mass of the order of 500 GeV. In this mass region for quark-anti-quark pair the additional Yukawa-type attraction due to Higgs mechanism is expected to emerge. This Higgs induced attraction greatly exceeds strong interaction between quarks and leads to the formation of bound states in both colour octet $S^{(8)}$ and singlet $S^{(1)}$ states. In the key of recent works on significance of colour octet channel for production of colour singlet state of fourth generation $Q\\bar{Q}$ we calculated the binding energies for both octet and singlet states. Such attraction localizes quarks in extremely small area. Hence colour octet pair of fourth generation quarks can form the "nucleus" and together with colour neutralizing light particle that is captured by strong interaction in orbit around the nucleus, create particle, similar by its structure to Deuterium.
A narrow quasi-bound state of the DNN system
International Nuclear Information System (INIS)
We have investigated a charmed system of DNN (composed of two nucleons and a D meson) by a complementary study with a variational calculation and a Faddeev calculation with fixed-center approximation (Faddeev-FCA). In the present study, we employ a DN potential based on a vector–meson exchange picture in which a resonant Λc(2595) is dynamically generated as a DN quasi-bound state, similarly to the Λ(1405) as a K¯N one in the strange sector. As a result of the study of variational calculation with an effective DN potential and three kinds of NN potentials, the DNN(Jπ=0−,I=1/2) is found to be a narrow quasi-bound state below Λc(2595)N threshold: total binding energy ∼225 MeV and mesonic decay width ∼25 MeV. On the other hand, the Jπ=1− state is considered to be a scattering state of Λc(2595) and a nucleon. These results are essentially supported by the Faddeev-FCA calculation. By the analysis of the variational wave function, we have found a unique structure in the DNN(Jπ=0−,I=1/2) such that the D meson stays around the center of the total system due to the heaviness of the D meson
Static and dynamic properties of QCD bound states
International Nuclear Information System (INIS)
The QCD phenomenology can be faced with the framework of the coupled quark DSE, meson BSE and baryon Faddeev equation, providing non-perturbative, continuum and Poincare invariant scientific approach. The research performed throughout this thesis is twofold. From one perspective we focus on the investigation of mass spectra for mesons with total spin quantum number J=3 and arising Regge-trajectory for natural parity states JPC=1--,2++,3-- within rainbow-ladder single gluon exchange model. The other findings are concerning the impact of the pion cloud effect on J>2 meson states, baryon masses, namely on Nucleon and Delta three-body bound states and meson dynamical properties like the pion form factor.
Static and dynamic properties of QCD bound states
Energy Technology Data Exchange (ETDEWEB)
Kubrak, Stanislav
2015-07-01
The QCD phenomenology can be faced with the framework of the coupled quark DSE, meson BSE and baryon Faddeev equation, providing non-perturbative, continuum and Poincare invariant scientific approach. The research performed throughout this thesis is twofold. From one perspective we focus on the investigation of mass spectra for mesons with total spin quantum number J=3 and arising Regge-trajectory for natural parity states J{sup PC}=1{sup --},2{sup ++},3{sup --} within rainbow-ladder single gluon exchange model. The other findings are concerning the impact of the pion cloud effect on J>2 meson states, baryon masses, namely on Nucleon and Delta three-body bound states and meson dynamical properties like the pion form factor.
The inverse problem in the case of bound states
International Nuclear Information System (INIS)
We investigate the inverse problem for bound states in the D = 3 dimensional space. The potential is assumed to be local and spherically symmetric. The present method is based on relationships connecting the moments of the ground state density to the lowest energy of each state of angular momentum l. The reconstruction of the density ρ(r) from its moments is achieved by means of the series expansion of its Fourier transform F(q). The large q-behavior is described by Pade approximants. The accuracy of the solution depends on the number of known moments. The uniqueness is achieved if this number is infinite. In practice, however, an accuracy better than 1% is obtained with a set of about 15 levels. The method is tested on a simple example, and applied to three different spectra
The search for deeply bound kaonic states with FOPI
International Nuclear Information System (INIS)
Full text: New formation mechanisms for the creation of dense, exotic nuclear systems involving strangeness were recently proposed by Y. Akaishi and T. Yamazaki. Their calculations show that a K- might form deeply bound states in light nuclei - so called kaonic clusters - with central densities of several times the normal nuclear density. In the presentation a short overview of these exotic nuclear systems will be given and a new experiment with FOPI at GSI will be discussed. The aim of this experiment was to search for the simplest cluster - a ppK- state. This state is produced at GSI in the following high energy reaction: p + ''d'' → ppK- + K+ + n'' with incident energies of 3.5 GeV. The experimental set-up will be presented in detail. (author)
Autodetachment spectroscopy of the aluminum oxide anion dipole bound state
Energy Technology Data Exchange (ETDEWEB)
Mascaritolo, Kyle J.; Gardner, Adrian M.; Heaven, Michael C., E-mail: mheaven@emory.edu [Department of Chemistry, Emory University, Atlanta, Georgia 30322 (United States)
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.
Configuration space Faddeev formalism: Λ + n + n bound state search
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).
Tetraquark bound states in a Bethe-Salpeter approach
Heupel, Walter; Eichmann, Gernot; Fischer, Christian S.
2012-01-01
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 o...
Quarkonium-nucleus bound states from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Beane, S. R. [Univ. of Washington, Seattle, WA (United States); Chang, E. [Univ. of Washington, Seattle, WA (United States); Cohen, S. D. [Univ. of Washington, Seattle, WA (United States); Detmold, W. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lin, H. -W. [Univ. of Washington, Seattle, WA (United States); Orginos, K. [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Parreño, A. [Univ., de Barcelona, Marti Franques (Spain); Savage, M. J. [Univ. of Washington, Seattle, WA (United States)
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.
Resonantly Trapped Bound State in the Continuum Laser
Lepetit, Thomas; Kodigala, Ashok; Bahari, Babak; Fainman, Yeshaiahu; Kanté, Boubacar
2015-01-01
Cavities play a fundamental role in wave phenomena from quantum mechanics to electromagnetism and dictate the spatiotemporal physics of lasers. In general, they are constructed by closing all "doors" through which waves can escape. We report, at room temperature, a bound state in the continuum laser that harnesses optical modes residing in the radiation continuum but nonetheless may possess arbitrarily high quality factors. These counterintuitive cavities are based on resonantly trapped symmetry-compatible modes that destructively interfere. Our experimental demonstration opens exciting avenues towards coherent sources with intriguing topological properties for optical trapping, biological imaging, and quantum communication.
R-Matrix Calculations for Few-Quark Bound States
Shalchi, M A
2016-01-01
The R-matrix method is implemented to study the heavy charm and bottom diquark, triquark, tetraquark and pentaquarks in configuration space, as the bound states of quark-antiquark, diquark-quark, diquark-antidiquark and diquark-antitriquark systems, respectively. The mass spectrum and the size of these systems are calculated for different partial wave channels. The calculated masses are compared with recent theoretical results obtained by %the solution of Lippmann-Schwinger equation other methods in momentum and configuration spaces and also by available experimental data.
Three-body bound states in finite volume with EFT
International Nuclear Information System (INIS)
Three particles with large scattering length display a universal spectrum of three-body bound states called ''Efimov trimers''. We calculate the modification of the Efimov trimers of three identical bosons in a finite cubic box and compute the dependence of their energies on the box size using effective field theory. The renormalization of the effective field theory in the finite volume is explicitly verified. We investigate the effects of partial wave mixing and study the behavior of shallow trimers near the dimer energy. Finally, we present first results for the triton in a finite volume.
International Nuclear Information System (INIS)
Applying perturbative QCD methods recently seen to give a good description of the two-body hadronic decays of the B meson, we address the question of bound-state effects on the decay B→K*γ. Consistent with most analyses, we demonstrate that gluonic penguin diagrams, with photonic bremsstrahlung off a quark, change the decay rate by only a few percent. Using an asymptotic distribution amplitude for the K* and just the standard model, we can obtain a branching ratio of a few x10-5, consistent with the observed rate
Stieltjes electrostatic model interpretation for bound state problems
Indian Academy of Sciences (India)
K V S Shiv Chaitanya
2014-07-01
In this paper, it is shown that Stieltjes electrostatic model and quantum Hamilton Jacobi formalism are analogous to each other. This analogy allows the bound state problem to mimic as unit moving imaginary charges $i\\hbar$, which are placed in between the two fixed imaginary charges arising due to the classical turning points of the potential. The interaction potential between unit moving imaginary charges $i\\hbar$ is given by the logarithm of the wave function. For an exactly solvable potential, this system attains stable equilibrium position at the zeros of the orthogonal polynomials depending upon the interval of the classical turning points.
Bound states of string networks and D-branes
International Nuclear Information System (INIS)
We show the existence of nonthreshold bound states of (p, q) string networks and D3-branes, preserving 1/4 of the full type-IIB supersymmetry, interpreted as string networks 'dissolved' in D3-branes. We also explicitly write down the expression for the mass density of the system and discuss the extension of the construction to other Dp -branes. Differences in our construction of string networks with the ones interpreted as dyons in N=4 gauge theories are also pointed out
Pionic instabilities in high-energy heavy ion collisions
International Nuclear Information System (INIS)
The study of heavy ion reactions includes the determination of whether pionic instabilities can exist at the densities and excitation energies expected in heavy ion collisions, the calculation of growth rates of unstable pion modes, and the determination of the effect such instabilities would have on the dynamics in heavy ion collisions. 14 references
Fingerprints of Majorana Bound States in Aharonov-Bohm Geometry
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.
Topological nature of bound states in the radiation continuum
Zhen, Bo; Lu, Ling; Stone, A Doug; Soljacic, Marin
2014-01-01
Bound states in the continuum (BICs) are unusual solutions of wave equations describing light or matter: they are discrete and spatially bounded, but exist at the same energy as a continuum of states which propagate to infinity. Until recently, BICs were constructed through fine-tuning parameters in the wave equation or exploiting the separability of the wave equation due to symmetry. More recently, BICs that that are both robust and not symmetry-protected (accidental) have been predicted and experimentally realized in periodic structures; the simplest such system is a periodic dielectric slab, which also has symmetry-protected BICs. Here we show that both types of BICs in such systems are vortex centers in the polarization direction of far-field radiation. The robustness of these BICs is due to the existence of conserved and quantized topological charges, defined by the number of times the polarization vectors wind around the vortex centers. Such charges can only be generated or annihilated by making large c...
Bound states and entanglement in the excited states of quantum spin chains
International Nuclear Information System (INIS)
We investigate the entanglement properties of the excited states of the spin- (1/2) Heisenberg (XXX) chain with isotropic antiferromagnetic interactions, by exploiting the Bethe ansatz solution of the model. We consider eigenstates obtained from both real and complex solutions (‘strings’) of the Bethe equations. Physically, the former are states of interacting magnons, whereas the latter contain bound states of groups of particles. We first focus on the situation with few particles in the chain. Using exact results and semiclassical arguments, we derive an upper bound SMAX for the entanglement entropy. This exhibits an intermediate behaviour between logarithmic and extensive, and it is saturated for highly-entangled states. As a function of the eigenstate energy, the entanglement entropy is organized in bands. Their number depends on the number of blocks of contiguous Bethe–Takahashi quantum numbers. In the presence of bound states a significant reduction in the entanglement entropy occurs, reflecting that a group of bound particles behaves effectively as a single particle. Interestingly, the associated entanglement spectrum shows edge-related levels. At a finite particle density, the semiclassical bound SMAX becomes inaccurate. For highly-entangled states SA∝ Lc, with Lc the chord length, signalling the crossover to extensive entanglement. Finally, we consider eigenstates containing a single pair of bound particles. No significant entanglement reduction occurs, in contrast with the few-particle case. (paper)
Bound states for non-symmetric evolution Schroedinger potentials
Energy Technology Data Exchange (ETDEWEB)
Corona, Gulmaro Corona [Area de Analisis Matematico y sus Aplicaciones, Universidad Autonoma Metropolitana-Azcapotalco, Atzcapotzalco, DF (Mexico)). E-mail: ccg@correo.azc.uam.mx
2001-09-14
We consider the spectral problem associated with the evolution Schroedinger equation, (D{sup 2}+ k{sup 2}){phi}=u{phi}, where u is a matrix-square-valued function, with entries in the Schwartz class defined on the real line. The solution {phi}, called the wavefunction, consists of a function of one real variable, matrix-square-valued with entries in the Schwartz class. This problem has been dealt for symmetric potentials u. We found for the present case that the bound states are localized similarly to the scalar and symmetric cases, but by the zeroes of an analytic matrix-valued function. If we add an extra condition to the potential u, we can determine these states by an analytic scalar function. We do this by generalizing the scalar and symmetric cases but without using the fact that the Wronskian of a pair of wavefunction is constant. (author)
Bound states for non-symmetric evolution Schroedinger potentials
International Nuclear Information System (INIS)
We consider the spectral problem associated with the evolution Schroedinger equation, (D2+ k2)φ=uφ, where u is a matrix-square-valued function, with entries in the Schwartz class defined on the real line. The solution φ, called the wavefunction, consists of a function of one real variable, matrix-square-valued with entries in the Schwartz class. This problem has been dealt for symmetric potentials u. We found for the present case that the bound states are localized similarly to the scalar and symmetric cases, but by the zeroes of an analytic matrix-valued function. If we add an extra condition to the potential u, we can determine these states by an analytic scalar function. We do this by generalizing the scalar and symmetric cases but without using the fact that the Wronskian of a pair of wavefunction is constant. (author)
The quantum probability equation: I. Bound state perturbation theory
International Nuclear Information System (INIS)
The partial-wave Schroedinger 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. (author)
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Sabyasachi, E-mail: sabyaphy@gmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sao Paulo, SP (Brazil). Instituto de Fisica Teorica
2015-12-15
Owing to the Kubo relation, the shear viscosities of pionic and nucleonic components have been evaluated from their corresponding retarded correlators of viscous stress tensor in the static limit, which become non-divergent only for the non-zero thermal widths of the constituent particles. In the real-time thermal field theory, the pion and nucleon thermal widths have respectively been obtained from the pion self-energy for different meson, baryon loops, and the nucleon self-energy for different pion-baryon loops. We have found non-monotonic momentum distributions of pion and nucleon thermal widths, which have been integrated out by their respective Bose-enhanced and Pauli-blocked phase space factors during evaluation of their shear viscosities. The viscosity to entropy density ratio for this mixed gas of pion-nucleon system decreases and approaches its lower bound as the temperature and baryon chemical potential increase within the relevant domain of hadronic matter. (author)
International Nuclear Information System (INIS)
Owing to the Kubo relation, the shear viscosities of pionic and nucleonic components have been evaluated from their corresponding retarded correlators of viscous stress tensor in the static limit, which become non-divergent only for the non-zero thermal widths of the constituent particles. In the real-time thermal field theory, the pion and nucleon thermal widths have respectively been obtained from the pion self-energy for different meson, baryon loops, and the nucleon self-energy for different pion-baryon loops. We have found non-monotonic momentum distributions of pion and nucleon thermal widths, which have been integrated out by their respective Bose-enhanced and Pauli-blocked phase space factors during evaluation of their shear viscosities. The viscosity to entropy density ratio for this mixed gas of pion-nucleon system decreases and approaches its lower bound as the temperature and baryon chemical potential increase within the relevant domain of hadronic matter. (author)
Production and decay of scalar stoponium bound states
Drees, Manuel
1994-01-01
In this paper we discuss possible signatures for the production of scalar \\stst\\ (stoponium) bound states \\sigst\\ at hadron colliders, where \\st\\ is the lighter scalar top eigenstate. We first study the decay of \\sigst; explicit expressions are given for all potentially important decay modes. If \\st\\ has unsuppressed two--body decays, they will always overwhelm the annihilation decays of \\sigst. Among the latter, we find that usually either the $gg$ or $hh$ final state dominates, depending on the size of the off--diagonal entry of the stop mass matrix; $h$ is the lighter neutral scalar Higgs boson of the minimal supersymmetric model. If \\msig\\ happens to be close to the mass of one of the neutral scalar Higgs bosons, $Q \\bar{Q}$ final states dominate ($Q=b$ or $t$). \\ww\\ and $ZZ$ final states are subdominant. We argue that $\\sigst \\rightarrow \\gamgam$ decays offer the best signal for stoponium production at hadron colliders. The tevatron should be able to close the light stop window left open by LEP searches,...
G-factors of hole bound states in spherically symmetric potentials in cubic semiconductors
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.
G-factors of hole bound states in spherically symmetric potentials in cubic semiconductors
Miserev, D. S.; Sushkov, O. P.
2015-01-01
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.
Universal Bounds on Charged States in 2d CFT and 3d Gravity
Benjamin, Nathan; Fitzpatrick, A Liam; Kachru, Shamit
2016-01-01
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 than 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.
Tetra quark bound states in a Bethe-Salpeter approach
Energy Technology Data Exchange (ETDEWEB)
Heupel, Walter; Eichmann, Gernot [Institut fuer Theoretische Physik, Justus-Liebig-Universitaet Giessen, D-35392 Giessen (Germany); Fischer, Christian S., E-mail: christian.fischer@theo.physik.uni-giessen.de [Institut fuer Theoretische Physik, Justus-Liebig-Universitaet Giessen, D-35392 Giessen (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, D-64291 Darmstadt (Germany)
2012-12-05
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 f{sub 0}(600). Our results furthermore suggest the presence of a potentially narrow all-charm tetraquark in the mass region 5-6 GeV.
Tetraquark bound states in a Bethe-Salpeter approach
Heupel, Walter; Fischer, Christian S
2012-01-01
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 f_0(600). Our results furthermore suggest the presence of a potentially narrow all-charm tetraquark in the mass region 5-6 GeV.
Tetraquark bound states in a Bethe-Salpeter approach
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.
Bound-state properties from field-theory correlators
Melikhov, Dmitri
2011-01-01
We discuss the details of calculating hadron properties from the OPE for correlators of quark currents in QCD, which constitutes the basis of the method of QCD sum rules. The main emphasis is laid on gaining control over the systematic uncertainties of the hadron parameters obtained within this method. We start with examples from quantum mechanics, where bound-state properties may be calculated independently in two ways: exactly, by solving the Schroedinger equation, and approximately, by the method of sum rules. Knowing the exact solution allows us to control each step of the sum-rule extraction procedure. On the basis of this analysis, we formulate several improvements of the method of sum rules. We then apply these modifications to the analysis of the decay constants of heavy mesons.
Bound-state properties from field-theory correlators
International Nuclear Information System (INIS)
We discuss the details of calculating hadron properties from the OPE for correlators of quark currents in QCD, which constitutes the basis of the method of QCD sum rules. The main emphasis is laid on gaining control over the systematic uncertainties of the hadron parameters obtained within this method. We start with examples from quantum mechanics, where bound-state properties may be calculated independently in two ways: exactly, by solving the Schroedinger equation, and approximately, by the method of sum rules. Knowing the exact solution allows us to control each step of the sum-rule extraction procedure. On the basis of this analysis, we formulate several improvements of the method of sum rules. We then apply these modifications to the analysis of the decay constants of heavy mesons.
Baryons as relativistic three-quark bound states
Eichmann, Gernot; Williams, Richard; Alkofer, Reinhard; Fischer, Christian S
2016-01-01
We review the spectrum and electromagnetic properties of baryons described as relativistic three-quark bound states within QCD. The composite nature of baryons results in a rich excitation spectrum, whilst leading to highly non-trivial structural properties explored by the coupling to external (electromagnetic and other) currents. Both present many unsolved problems despite decades of experimental and theoretical research. We discuss the progress in these fields from a theoretical perspective, focusing on nonperturbative QCD as encoded in the functional approach via Dyson-Schwinger and Bethe-Salpeter equations. We give a systematic overview as to how results are obtained in this framework and explain technical connections to lattice QCD. We also discuss the mutual relations to the quark model, which still serves as a reference to distinguish 'expected' from 'unexpected' physics. We confront recent results on the spectrum of non-strange and strange baryons, their form factors and the issues of two-photon proce...
The structure of the D0-D4 bound state
International Nuclear Information System (INIS)
We derive a set of equations for the wavefunction describing the marginal bound state of a single D0-brane with a single D4-brane. These are equations determining the vacuum of an N=8 Abelian gauge theory with a charged hypermultiplet. We then solve these equations for the most general possible zero-energy solution using a Taylor series. We find that there are an infinite number of such solutions of which only one must be normalizable. We explore the structure of a normalizable solution under the assumption of an asymptotic expansion. Even the leading terms in the asymptotic series, which should reflect the supergravity solution, are unusual. Through the Spin(5) flavor symmetry, the modes which are massive at long distance actually influence the leading behavior. Lastly, we show that the vacuum equations can quite remarkably be reduced to a single equation involving one unknown function. The resulting equation has a surprisingly simple and suggestive form
Cooperativity, partially bound states, and enthalpy-entropy compensation.
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
Bound states in the continuum in open acoustic resonators
Lyapina, A A; Pilipchuk, A S; Sadreev, A F
2015-01-01
We consider bound states in the continuum (BSC) or embedded trapped modes in two- and three-dimensional acoustic axisymmetric duct-cavity structures. We demonstrate numerically that under variation of the length of the cavity multiple BSCs occur due to the Friedrich-Wintgen two-mode full destructive interference mechanism. The BSCs are detected by tracing the resonant widths to the points of the collapse of Fano resonances where one of the two resonant modes acquires infinite life-time. It is shown that the approach of the acoustic coupled mode theory cast in the truncated form of a two-mode approximation allows us to analytically predict the BSC frequencies and shape functions to a good accuracy in both two and three dimensions.
Dark matter and stable bound states of primordial black holes
Chavda, L K; Chavda, Abhijit L.
2002-01-01
We present three reasons for the formation of gravitational bound states of primordial black holes,called holeums,in the early universe.Using Newtonian gravity and nonrelativistic quantum mechanics we find a purely quantum mechanical mass-dependant exclusion property for the nonoverlap of the constituent black holes in a holeum.This ensures that the holeum occupies space just like ordinary matter.A holeum emits only gravitational radiation whose spectrum is an exact analogue of that of a hydrogen atom. A part of this spectrum lies in the region accessible to the detectors being built.The holeums would form haloes around the galaxies and would be an important component of the dark matter in the universe today.They may also be the constituents of the invisible domain walls in the universe.
Rapid thermal co-annihilation through bound states
Kim, Seyong
2016-01-01
The co-annihilation rate of heavy particles close to thermal equilibrium, which plays a role in many classic dark matter scenarios, can be "simulated" in QCD by considering the pair annihilation rate of a heavy quark and antiquark at a temperature of a few hundred MeV. We show that the so-called Sommerfeld factors, parameterizing the rate, can be defined and measured non-perturbatively within the NRQCD framework. Lattice measurements indicate a modest suppression in the octet channel, in reasonable agreement with perturbation theory, and a large enhancement in the singlet channel, much above the perturbative prediction. We suggest that the additional enhancement originates from bound state formation and subsequent decay, omitted in previous estimates of thermal Sommerfeld factors, which were based on Boltzmann equations governing single-particle phase space distributions.
Tetra quark bound states in a Bethe-Salpeter approach
International Nuclear Information System (INIS)
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.
Dark matter and stable bound states of primordial black holes
International Nuclear Information System (INIS)
We present three reasons for the formation of gravitational bound states of primordial black holes, called holeums, in the early universe. Using Newtonian gravity and nonrelativistic quantum mechanics we find a purely quantum mechanical mass-dependent exclusion property for the nonoverlap of the constituent black holes in a holeum. This ensures that the holeum occupies space just like ordinary matter. A holeum emits only gravitational radiation whose spectrum is an exact analogue of that of a hydrogen atom. A part of this spectrum lies in the region accessible to the detectors being built. The holeums would form haloes around the galaxies and would be an important component of the dark matter in the universe today. They may also be the constituents of the invisible domain walls in the universe
Probing the Dark Sector with Dark Matter Bound States
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.
Probing the Dark Sector with Dark Matter Bound States.
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
Two-vibron bound states in the β-Fermi-Pasta-Ulam model
Institute of Scientific and Technical Information of China (English)
Hu Xin-Guang; Tang Yi
2008-01-01
This paper studies the two-vibron bound states in the β-Fermi-Pasta-Ulam model by means of the number conserving approximation combined with the number state method.The results indicate that on-site,adjacent-site and mixed two-vibron bound states may exist in the model.Specially,wave number has a significant effect on such bound states,which may be considered as the quantum effects of the localized states in quantum systems.
Three-nucleon problem: trinucleon bound states and trinucleon interactions
International Nuclear Information System (INIS)
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
Lower bound on concurrence for arbitrary-dimensional tripartite quantum states
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.
Rostami, R
2016-01-01
To investigate the high mass dilepton production cross section produced due to the Drell-Yan process in hadronic collisions such as nucleon- nucleus, the valence and sea quarks distribution functions inside nucleus is used. In this study, in the framework of the shell and Fermi gas models, by adding quarks distribution functions of pions inside nucleus besides the quarks distribution functions of bound nucleons, the changes in the dilepton production cross section were investigated. For this reason, pionic contribution in the structure function of 63Cunucleus and its EMC ratio was first studied using the aforementioned models. Then, in the framework of the Drell-Yan process using GRV's nucleons and pions quarks distribution functions, the high mass dilepton production cross section in p-cu collision was calculated and compared with the available experimental data. The extracted results, based on the two mentioned models, were greatly the same and by considering the pionic contribution, the theoretical results...
Directory of Open Access Journals (Sweden)
R. Rostami
2016-01-01
Full Text Available For detailed explanation of the experimental results of lepton production cross section in hadronic collisions such as nucleon-nucleon or nucleon-nuclei, it is of great importance to use quarks and sea quarks distribution function inside free and bound nucleons. In this paper, the role of pion cloud inside the nucleus in the structure function of Cu and Pt nuclei and the EMC ratio of these nuclei were investigated by using harmonic oscillator model. Then, in the framework of the Drell-Yan process and conventional nuclear theory, GRV’s quarks distribution functions and pionic quarks distribution functions were used to calculate lepton and antilepton production cross section in p-Cu and p-Pt scattering. From the results and based on the mentioned model, by considering pionic contribution, the theoretical results are improved.
The pionic Drell–Yan process: a brief survey
International Nuclear Information System (INIS)
The Drell–Yan process is an invaluable tool for probing the structure of hadrons, and the pion-induced Drell–Yan process is unique in its sensitivity to several subtleties of the partonic structure. This is a brief review of the pionic Drell–Yan process with particular emphasis on the dilepton angular distributions and nuclear modification of the parton distributions (the EMC effect). (author)
Unitary Transformations in Quantum Field Theory and Bound States
Shebeko, A V
2001-01-01
Finding the eigenstates of the total Hamiltonian H or its diagonalization is the important problem of quantum physics. However, in relativistic quantum field theory (RQFT) its complete and exact solution is possible for a few simple models only. Unitary transformations (UT's) considered in this survey do not diagonalize H, but convert H into a form which enables us to find approximately some H eigenstates. During the last years there have appeared many papers devoted to physical applications of such UT's. Our aim is to present a systematic and self-sufficient exposition of the UT method. The two general kinds of UT's are pointed out, distinct variations of each kind being possible. We consider in detail the problem of finding the simplest H eigenstates for interacting mesons and nucleons using the so-called ``clothing'' UT and Okubo's UT. These UT's allow us to suggest definite approaches to the problem of two-particle (deuteron-like) bound states in RQFT. The approaches are shown to yield the same two-nucleo...
Bound States via Higgs Exchanging and Resonant Di-Higgs
Kang, Zhaofeng
2016-01-01
The standard model (SM)-like Higgs boson $h$ has spin zero and light mass around weak scale, so it has the potential to mediate a new and relatively strong force for the particle $\\phi$ in the new physics (NP) sector; then $\\phi$ may form bound state $B_h$ via exchanging $h$. This phenomena may arise in a wide context, for instance composite Higgs, supersymmetry (SUSY) and radiative neutrino (or more widely in the models with a strong Higgs portal for triggering classical scale symmetry breaking or strong first-order phase transition). For illustration we focus on two typical examples, the stop/sbottom sector and an inert Higgs doublet. Furthermore, we point out that $B_h$ must give rise to a clear resonant di-Higgs signature, which recently has been extensively searched for at the large hadron collider (LHC). Moreover, Higgs radiative decay such as to di-photon probably will be significantly modified provided that $\\phi$ is charged or/and colored.
Unified description of bound, resonant and scattering states
International Nuclear Information System (INIS)
Recently we have introduced a general method for calculating the discrete Hilbert-space basis representation of the Green's operators of those Hamiltonians which have infinite symmetric tridiagonal matrix forms. The elements of this matrix are used in the calculation of the Green's matrix in terms of a three-term recurrence relation and continued fractions. We specified our general approach to the case of the Coulomb problem and the Coulomb-Sturmian basis associated with it. As a further step, we can combine this new way of calculating the Coulomb-Green's matrix with a technique of solving integral equations in discrete Hilbert-space-basis representations. This provides us with a quantum mechanical approximation method which is rather general in the sense that it is equally applicable to solving bound-, resonant- and scattering-state problems with practically any potential of physical relevance. The method is especially suited to problems where Coulomb-like asymptotics have to be treated, but the formalism also contains the case of the free Green's operator as a special case. (author)
Coexistence of bound and virtual-bound states in shallow-core to valence x-ray spectroscopies
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.
Supersymmetry Approaches to the Bound States of the Generalized Woods-Saxon Potential
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.
Normalization of the covariant three-body bound state vertex function
Adam, J; Savkli, C; Van Orden, J W; Gross, Franz; Savkli, Cetin
1997-01-01
The normalization condition for the relativistic three nucleon Bethe-Salpeter and Gross bound state vertex functions is derived, for the first time, directly from the three body wave equations. It is also shown that the relativistic normalization condition for the two body Gross bound state vertex function is identical to the requirement that the bound state charge be conserved, proving that charge is automatically conserved by this equation.
Near optimal bounds on quantum communication complexity of single-shot quantum state redistribution
Anshu, Anurag; Devabathini, Vamsi Krishna; Jain, Rahul
2014-01-01
We show near optimal bounds on the worst case quantum communication of single-shot entanglement-assisted one-way quantum communication protocols for the {\\em quantum state redistribution} task and for the sub-tasks {\\em quantum state splitting} and {\\em quantum state merging}. Our bounds are tighter than previously known best bounds for the latter two sub-tasks. A key technical tool that we use is a {\\em convex-split} lemma which may be of independent interest.
Free energy barrier for melittin reorientation from a membrane-bound state to a transmembrane state
Irudayam, Sheeba J.; Pobandt, Tobias; Berkowitz, Max L.
2013-01-01
An important step in a phospholipid membrane pore formation by melittin antimicrobial peptide is a reorientation of the peptide from a surface into a transmembrane conformation. In this work we perform umbrella sampling simulations to calculate the potential of mean force (PMF) for the reorientation of melittin from a surface-bound state to a transmembrane state and provide a molecular level insight into understanding peptide and lipid properties that influence the existence of the free energ...
Bound states and critical behavior of the Yukawa potential
Institute of Scientific and Technical Information of China (English)
LI; Yongyao
2006-01-01
[1]Yukawa,H.,On the interaction of elementary particles,Proc.Phys.Math Soc.Jap.,1935,17:48-57.[2]Sachs,R.,Goeppert-Mayer,M.,Calculations on a new neutron-proton interaction potential,Phys.Rev.,1938,53:991-993.[3]Harris,G.,Attractive two-body interactions in partially ionized plasmas,Phys.Rev.,1962,125:1131-1140.[4]Schey,H.,Schwartz,J.,Counting the bound states in short-range central potentials,Phys.Rev.B,1965,139:1428-1432.[5]Rogers,J.,Graboske,H.,Harwood,E.,Bound eigenstates of the static screened Coulomb poten-tial,Phys.Rev.A,1970,1:1577-1586.[6]McEnnan,J.,Kissel,L.,Pratt,R.,Analytic perturbation theory for screened Coulomb potentials:non-relativistic case,Phys.Rev.A,1976,13:532-559.[7]Gerry,C.,Estimates of the ground states of the Yukawa potential from the Bogoliubov inequality,J.Phys.A,1984,17:L313-L315.[8]Kr(o)ger,H.,Girard,R.,Dufour,G.,Direct calculation of the S matrix in coordinate space,Phys.Rev.C,1988,37:486-496.[9]Girard,R.,Kr(o)ger,H.,Labelle,P.et al.,Computation of a long time evolution in a Schr(o)dinger system,Phys.Rev.A,1988,37:3195-3200.[10]Garavelli,S.,Oliveira,F.,Analytical solution for a Yukawa-type potential,Phys.Rev.Lett.,1991,66:1310-1313.[11]Gomes,O.,Chacham,H.,Mohallem,J.,Variational calculations for the bound-unbound transition of the Yukawa potential,Phys.Rev.A,1994,50:228-231.[12]Yukalov,V.,Yukalova,E.,Oliveira,F.,Renormalization-group solutions for Yukawa potential,J.Phys.A,1998,31:4337-4348.[13]Brau,F.,Necessary and sufficient conditions for existence of bound states in a central potential,J.Phys.A,2003,36:9907-9913.[14]Bertini,L.,Mella,M.,Bressanini,D.et al.,Borromean binding in H-2 with Yukawa potential:a nonadiabatic quantum Monte Carlo study,Phys.Rev.A,2004,69:042504.[15]Dean,D.,Drummond,I.,Horgan,R.,Effective diffusion constant in a two-dimensional medium of charged point scatterers,J.Phys.A,2004,37:2039-2046.[16]De-Leo,S.,Rotelli,P.,Amplification of coupling for Yukawa potentials,Phys.Rev.D,2004,69:034006.[17]Khrapak
Efimov effect and higher bound states in a three particle system
International Nuclear Information System (INIS)
The J=0 bound states for a system of three identical spinless particles interacting in pairs through delta-shell potentials are studied. The Efimov states are identified, and their wave functions obtained. A new family of bound states, which occurs for higher values of the attractive coupling strength was found
Continuum bound states as surface states of a finite periodic system
International Nuclear Information System (INIS)
We discuss the relation between continuum bound states (CBSs) localized on a defect, and surface states of a finite periodic system. We model an experiment of Capasso et al. [F. Capasso, C. Sirtori, J. Faist, D. L. Sivco, S-N. G. Chu, and A. Y. Cho, Nature (London) 358, 565 (1992)] using the transfer-matrix method. We compute the rate for intrasubband transitions from the ground state to the CBS and derive a sum rule. Finally we show how to improve the confinement of a CBS while keeping the energy fixed
Quantum Chernoff bound as a measure of efficiency of quantum cloning for mixed states
Ghiu, Iulia
2014-01-01
In this paper we investigate the efficiency of quantum cloning of $N$ identical mixed qubits. We employ a recently introduced measure of distinguishability of quantum states called quantum Chernoff bound. We evaluate the quantum Chernoff bound between the output clones generated by the cloning machine and the initial mixed qubit state. Our analysis is illustrated by performing numerical calculation of the quantum Chernoff bound for different scenarios that involves the number of initial qubit...
Phenomenological Lagrangian functions and pionic decays of the heavy lepton tau
International Nuclear Information System (INIS)
After a description of the construction of nonlinear realizations of compact groups by means of the example of the three-dimensional realization of the group SU(2)xSU(2) the author constructs a Lagrangian density for the interaction of pions with the tau particle, from which the decay of the tau-particle into one, two, or three pions is calculated. Thereafter an extension of this model is presented, in which by the postulation of gauge invariance a set of vector fields is obtained which can be identified with the rho triplet and the A1 triplet. The pionic decays of the tau are calculated once more under the assumption of the occurrence of these particles as intermediate states. The obtained results are compared with the experimental situation. (HSI)
Scattering and Bound State Solutions of the Yukawa Potential within the Dirac Equation
International Nuclear Information System (INIS)
In the presence of spin symmetry case, we obtain bound and scattering states solutions of the Dirac equation for the equal scalar and vector Yukawa potentials for any spin-orbit quantum number κ. The approximate analytical solutions are presented for the bound and scattering states and scattering phase shifts
Solitons in superfluid (He-3)-A - Bound states on domain walls
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.
The $DKP$ equation in the Woods-Saxon potential well: Bound states
Boutabia-Chéraitia, Boutheina
2016-01-01
We solve the Duffin-Kemmer-P\\'{e}tiau equation in the presence of a spatially one-dimensional symmetric potential well. We compute the scattering state solutions and we derive conditions for transmission resonances. The bound solutions are derived by a graphic study and the appearance of the antiparticle bound state is discussed.
Ensemble-based characterization of unbound and bound states on protein energy landscape
Ruvinsky, Anatoly M; Tuzikov, Alexander V; Vakser, Ilya A
2012-01-01
Characterization of protein energy landscape and conformational ensembles is important for understanding mechanisms of protein folding and function. We studied ensembles of bound and unbound conformations of six proteins to explore their binding mechanisms and characterize the energy landscapes in implicit solvent. First, results show that bound and unbound spectra often significantly overlap. Moreover, the larger the overlap the smaller the RMSD between bound and unbound conformational ensembles. Second, the analysis of the unbound-to-bound changes points to conformational selection as the binding mechanism for four of the proteins. 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 considered outside of the complex. Fourth, the exhaustively long minimization, making small intra-rotamer adjustments, ...
Bounds on the Capacity of the Relay Channel with Noncausal State Information at Source
Zaidi, Abdellatif; Piantanida, Pablo; Vandendorpe, Luc
2010-01-01
We consider a three-terminal state-dependent relay channel with the channel state available non-causally at only the source. Such a model may be of interest for node cooperation in the framework of cognition, i.e., collaborative signal transmission involving cognitive and non-cognitive radios. We study the capacity of this communication model. One principal problem in this setup is caused by the relay's not knowing the channel state. In the discrete memoryless (DM) case, we establish lower bounds on channel capacity. For the Gaussian case, we derive lower and upper bounds on the channel capacity. The upper bound is strictly better than the cut-set upper bound. We show that one of the developed lower bounds comes close to the upper bound, asymptotically, for certain ranges of rates.
Bound entangled states with a private key and their classical counterpart.
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
The effect of η-η' mixing in the bound state version of the Skyrme model
International Nuclear Information System (INIS)
The η-η' mixing is incorporated in the symmetry breaking term in the extended Skyrme model Lagrangian. Besides η-soliton bound states, an s-wave and a p-wave η'-soliton bound states are found. After fixing the value of the strength parameter X of the ''alternative term'' to fit the s-wave η'-soliton bound state to the N(1535) negative-parity nucleon resonance, the η-soliton bound states disappear. Then only η'-soliton bound states are identified with nucleon resonances (I=1/2) and delta resonances (I=3/2). The predicted resonance masses agree well with experimental values. The decay widths ΓN*→N+η of the relevant nucleon resonances are also calculated to explain why these particles have large branching ratios in the ηN channel. (orig.)
Dynamics of F/D networks: the role of bound states
International Nuclear Information System (INIS)
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
A differential method for bounding the ground state energy
Mouchet, A
2005-01-01
For a wide class of Hamiltonians, a novel method to obtain lower and upper bounds for the lowest energy is presented. Unlike perturbative or variational techniques, this method does not involve the computation of any integral (a normalisation factor or a matrix element). It just requires the determination of the absolute minimum and maximum in the whole configuration space of the local energy associated with a normalisable trial function (the calculation of the norm is not needed). After a general introduction, the method is applied to three non-integrable systems: the asymmetric annular billiard, the many-body spinless Coulombian problem, the hydrogen atom in a constant and uniform magnetic field. Being more sensitive than the variational methods to any local perturbation of the trial function, this method can used to systematically improve the energy bounds with a local skilled analysis; an algorithm relying on this method can therefore be constructed and an explicit example for a one-dimensional problem is...
Interacting quantum walkers: two-body bosonic and fermionic bound states
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.
Quasi-bound states, resonance tunnelling, and tunnelling times generated by twin symmetric barriers
Indian Academy of Sciences (India)
A Uma Maheswari; P Prema; S Mahadevan; C S Shastry
2009-12-01
In analogy with the definition of resonant or quasi-bound states used in three-dimensional quantal scattering, we define the quasi-bound states that occur in one-dimensional transmission generated by twin symmetric potential barriers and evaluate their energies and widths using two typical examples: (i) twin rectangular barrier and (ii) twin Gaussian-type barrier. The energies at which reflectionless transmission occurs correspond to these states and the widths of the transmission peaks are also the same as those of quasi-bound states. We compare the behaviour of the magnitude of wave functions of quasi-bound states with those for bound states and with the above-barrier state wave function. We deduce a Breit–Wigner-type resonance formula which neatly describes the variation of transmission coefficient as a function of energy at below-barrier energies. Similar formula with additional empirical term explains approximately the peaks of transmission coefficients at above-barrier energies as well. Further, we study the variation of tunnelling time as a function of energy and compare the same with transmission, reflection time and Breit–Wigner delay time around a quasi-bound state energy. We also find that tunnelling time is of the same order of magnitude as lifetime of the quasi-bound state, but somewhat larger.
Versatile mode-locked fiber laser with switchable operation states of bound solitons.
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
Photon-assisted tunneling through a topological superconductor with Majorana bound states
Energy Technology Data Exchange (ETDEWEB)
Tang, Han-Zhao; Zhang, Ying-Tao, E-mail: zhangyt@mail.hebtu.edu.cn [College of Physics, Hebei Normal University, Shijiazhuang 050024 (China); Liu, Jian-Jun, E-mail: liujj@mail.hebtu.edu.cn [College of Physics, Hebei Normal University, Shijiazhuang 050024 (China); Department of Physics, Shijiazhuang University, Shijiazhuang 050035 (China)
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.
Photon-assisted tunneling through a topological superconductor with Majorana bound states
Directory of Open Access Journals (Sweden)
Han-Zhao Tang
2015-12-01
Full Text Available 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.
On accurate computations of bound state properties in three- and four-electron atomic systems
Frolov, Alexei M
2016-01-01
Results of accurate computations of bound states in three- and four-electron atomic systems are discussed. Bound state properties of the four-electron lithium ion Li$^{-}$ in its ground $2^{2}S-$state are determined from the results of accurate, variational computations. We also consider a closely related problem of accurate numerical evaluation of the half-life of the beryllium-7 isotope. This problem is of paramount importance for modern radiochemistry.
Skyrmion model in 2+1 dimensions with soliton bound states
Energy Technology Data Exchange (ETDEWEB)
Piette, B.; Zakrzewski, W.J. (Dept. of Mathematical Sciences, Univ. Durham (United Kingdom))
1993-03-22
We consider a class of skyrmion models in 2+1 dimensions which possess bound stable solitons. We show that these models have one-soliton solutions as well as static solutions corresponding to their bound states. We study the scattering and stability properties of these solutions, compute their energies and estimate their binding energies. (orig.).
Bound states of fermions on 2D lattice in a dilute limit
International Nuclear Information System (INIS)
We examine extended bound states in a dilute limit of the extended Hubbard model on the two-dimensional square lattice. By solving exactly the two-body problem we have determined the binding energies, mobilities and dispersion curves across the Brillouin zone for bound states of various symmetries. It turns out that the d-wave pairing is strongly favoured by the nnn hopping and the intersite local pairs can have small effective masses, even on the case of strong binding.We have also found a possibility of extended s-dx2-y2 mixing of the bound states. (author)
Taming the Yukawa potential singularity: improved evaluation of bound states and resonance energies
Energy Technology Data Exchange (ETDEWEB)
Alhaidari, A D [Shura Council, Riyadh 11212 (Saudi Arabia); Bahlouli, H [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Abdelmonem, M S [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)
2008-01-25
Using the tools of the J-matrix method, we absorb the 1/r singularity of the Yukawa potential in the reference Hamiltonian, which is handled analytically. The remaining part, which is bound and regular everywhere, is treated by an efficient numerical scheme in a suitable basis using the Gauss quadrature approximation. Analysis of resonance energies and bound states spectrum is performed using the complex scaling method, where we show their trajectories in the complex energy plane and construct a video showing how bound states cross over into resonance states by varying the potential parameters. (fast track communication)
Pair creation induced by transitions between electronic and positronic bound states
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.
An Improved Lower Bound Limit State Optimisation Algorithm
DEFF Research Database (Denmark)
Frier, Christian; Damkilde, Lars
2010-01-01
Limit State analysis has been used in engineering practice for many years e.g. the yield-line method for concrete slabs and slip-line solutions in geotechnics. In the recent years there has been an increased interest in numerical Limit State analysis, and today algorithms take into account the non...
An Improved Lower Bound Limit State Optimisation Algorithm
DEFF Research Database (Denmark)
Frier, Christian; Damkilde, Lars
2010-01-01
Limit State analysis has been used in manual design methods for decades e.g. the yield line theory for concrete slabs.......Limit State analysis has been used in manual design methods for decades e.g. the yield line theory for concrete slabs....
Fano effect and Andreev bound states in T-shape double quantum dots
Energy Technology Data Exchange (ETDEWEB)
Calle, A.M.; Pacheco, M. [Departamento de Física, Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso (Chile); Orellana, P.A., E-mail: orellana@ucn.cl [Departamento de Física, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile)
2013-09-02
In this Letter, we investigate the transport through a T-shaped double quantum dot coupled to two normal metal leads left and right and a superconducting lead. Analytical expressions of Andreev transmission and local density of states of the system at zero temperature have been obtained. We study the role of the superconducting lead in the quantum interferometric features of the double quantum dot. We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. Our results show that as a consequence of quantum interference and proximity effect, the transmission from normal to normal lead exhibits Fano resonances due to Andreev bound states. We find that this interference effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. - Highlights: • Transport properties of a double quantum dot coupled in T-shape configuration to conducting and superconducting leads are studied. • We report Fano antiresonances in the normal transmission due to the Andreev reflections in the superconducting lead. • We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. • Fano effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. • Andreev bound states survives even for strong dot-superconductor coupling.
Fano effect and Andreev bound states in T-shape double quantum dots
International Nuclear Information System (INIS)
In this Letter, we investigate the transport through a T-shaped double quantum dot coupled to two normal metal leads left and right and a superconducting lead. Analytical expressions of Andreev transmission and local density of states of the system at zero temperature have been obtained. We study the role of the superconducting lead in the quantum interferometric features of the double quantum dot. We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. Our results show that as a consequence of quantum interference and proximity effect, the transmission from normal to normal lead exhibits Fano resonances due to Andreev bound states. We find that this interference effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. - Highlights: • Transport properties of a double quantum dot coupled in T-shape configuration to conducting and superconducting leads are studied. • We report Fano antiresonances in the normal transmission due to the Andreev reflections in the superconducting lead. • We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. • Fano effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. • Andreev bound states survives even for strong dot-superconductor coupling
The bound state Aharonov-Bohm effect around a cosmic string revisited
Filgueiras, C.; Moraes, Fernando
2005-01-01
In this article we observe that the self-adjoint extension of the Hamiltonian of a particle moving around a shielded cosmic string gives rise to a gravitational analogue of the bound state Aharonov-Bohm effect.
Sufficient conditions for the existence of a bound state in the N-body problem
International Nuclear Information System (INIS)
Simple sufficient conditions for the existence of a bound state in the system of N particles interacting via a purely attractive two-body potential are provided. This method is based on a variational approach. (Author)
The dynamical gluon mass in the massless bound-state formalism
Ibanez, David
2014-01-01
We describe the phenomenon of dynamical gluon mass generation within the massless bound-state formalism, which constitutes the general framework for the systematic implementation of the Schwinger mechanism in non-Abelian gauge theories. The main ingredient of this formalism is the dynamical formation of bound states with vanishing mass, which gives rise to effective vertices containing massless poles; these vertices, in turn, trigger the Schwinger mechanism, and allow for the gauge-invariant generation of an effective gluon mass. In this particular approach, the gluon mass is directly related to quantities that are intrinsic to the bound-state formation itself, such as the "transition amplitude" and the corresponding "bound-state wave-function". Specifically, a set of powerful relations discussed in the text, allows one to determine the dynamical evolution of the gluon mass through a Bethe-Salpeter equation, which controls the dynamics of the relevant wave-function. In addition, it is possible to demonstrate ...
Strongly bound metastable states of B2 + 2
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).
Bound states in the dynamics of a dipole in the presence of a conical defect
De Ribeiro, C A L; Moraes, F; Furtado, Claudio; Moraes, Fernando
2005-01-01
In this work we investigate the quantum dynamics of an electric dipole in a $(2+1)$-dimensional conical spacetime. For specific conditions, the Schr\\"odinger equation is solved and bound states are found with the energy spectrum and eigenfunctions determined. We find that the bound states spectrum extends from minus infinity to zero with a point of accumulation at zero. This unphysical result is fixed when a finite radius for the defect is introduced.
Bound states in the two-dimension massive quantum electrodynamics (Qed2)
International Nuclear Information System (INIS)
This work studies the fermion-antifermion bound states in the (1+1)D two-dimension massive quantum electrodynamic in the 1/N expansion. The scattering matrices in the non-relativistic approximation have been calculated through TQC, and compared with the cross section in the Born approximation, and therefore the potential responsible by the interactions in the scattering processes have been obtained. Using Schroedinger equation, the existence of possible bound states have been investigated
Two-polariton bound states in the Jaynes-Cummings-Hubbard model
International Nuclear Information System (INIS)
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.
Quantum Chernoff bound as a measure of the efficiency of quantum cloning for mixed states
International Nuclear Information System (INIS)
In this paper we investigate the efficiency of quantum cloning of N identical mixed qubits. We employ a recently introduced measure of distinguishability of quantum states called the quantum Chernoff bound. We evaluate the quantum Chernoff bound between the output clones generated by the cloning machine and the initial mixed qubit state. Our analysis is illustrated by performing numerical calculation of the quantum Chernoff bound for different scenarios that involves the number of initial qubits N and the number of output imperfect copies M. (paper)