Search for deeply bound pionic states in 208Pb via radiative atomic capture of negative pions
Raywood, K. J.; Lange, J. B.; Jones, G.; Pavan, M.; Sevior, M. E.; Hutcheon, D. A.; Olin, A.; Ottewell, D.; Yen, S.; Lee, S. J.; Sim, K. S.; Altman, A.; Friedman, E.; Trudel, A.
1997-05-01
A search for narrow, deeply bound pionic atom states via atomic radiative capture of negative pions in a target of 208Pb was carried out for pion kinetic energies of 20 and 25 MeV. Although no clear signature of any such gamma ray emission could be observed in the data, fits of the gamma ray spectra between the energies of 12 and 42 MeV involving a quadratic background together with a pair of peaks (1s, 2p) whose relative intensity was taken from theory yielded an overall strength for the peaks which are consistent (to a 67% confidence level) with radiative capture whose integrated cross section is 20.0 +/- 10.0 μb/sr at 90° for 20 MeV incident pions. A lower probability (40% confidence level) result was obtained when the fit was carried out without the peaks included, just the continuum background.
The s-wave repulsion and deeply bound pionic atoms: fact and fancy
Friedman, E.; Gal, A.
2003-06-01
Fits to a large data set of pionic atoms show that the 'missing' s-wave repulsion is accounted for when a density dependence suggested recently by Weise is included in the isovector term of the s-wave pion optical potential. The importance of using large data sets is demonstrated and the role of deeply bound pionic atom states is discussed.
Search for deeply bound pionic states in {sup 208}Pb via radiative atomic capture of negative pions
Energy Technology Data Exchange (ETDEWEB)
Raywood, K.J.; Lange, J.B.; Jones, G.; Pavan, M. [Department of Physics, University of British Columbia, Vancouver, British Columbia, V6T 1Z1 (CANADA); Sevior, M.E. [School of Physics, University of Melbourne, Parkville Victoria, 3052 (Australia); Hutcheon, D.A.; Olin, A.; Ottewell, D.; Yen, S. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (CANADA); Lee, S.J.; Sim, K.S. [Department of Physics, Korea University, Seoul 136-701 (Korea); Altman, A. [Direx Medical Services, P.O. Box 4190, Petah-Tikva, 41920 (Israel); Friedman, E. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Trudel, A. [Simon Fraser University, Burnaby, British Columbia, V5A 1S6 (CANADA)
1997-05-01
A search for narrow, deeply bound pionic atom states via atomic radiative capture of negative pions in a target of {sup 208}Pb was carried out for pion kinetic energies of 20 and 25 MeV. Although no clear signature of any such gamma ray emission could be observed in the data, fits of the gamma ray spectra between the energies of 12 and 42 MeV involving a quadratic background together with a pair of peaks (1s, 2p) whose relative intensity was taken from theory yielded an overall strength for the peaks which are consistent (to a 67{percent} confidence level) with radiative capture whose integrated cross section is 20.0 {plus_minus} 10.0 {mu}b/sr at 90{degree} for 20 MeV incident pions. A lower probability (40{percent} confidence level) result was obtained when the fit was carried out without the peaks included, just the continuum background. {copyright} {ital 1997} {ital The American Physical Society}
Chiral dynamics of deeply bound pionic atoms.
Kolomeitsev, E E; Kaiser, N; Weise, W
2003-03-01
We present and discuss a systematic calculation, based on two-loop chiral perturbation theory, of the pion-nuclear s-wave optical potential. A proper treatment of the explicit energy dependence of the off-shell pion self-energy together with (electromagnetic) gauge invariance of the Klein-Gordon equation turns out to be crucial. Accurate data for the binding energies and widths of the 1s and 2p levels in pionic 205Pb and 207Pb are well reproduced without need for a notorious "missing repulsion" in the pion-nuclear s-wave optical potential. The connection with the in-medium change of the pion decay constant is clarified.
Narrow deeply bound K- atomic states
Friedman, E.; Gal, A.
1999-07-01
Using optical potentials fitted to a comprehensive set of strong interaction level shifts and widths in K- atoms, we predict that the K- atomic levels which are inaccessible in the atomic cascade process are generally narrow, spanning a range of widths about 50-1500 keV over the entire periodic table. The mechanism for this narrowing is different from the mechanism for narrowing of pionic atom levels. Examples of such `deeply bound' K- atomic states are given, showing that in many cases these states should be reasonably well resolved. Several reactions which could be used to form these `deeply bound' states are mentioned. Narrow deeply bound states are expected also in overlinep atoms.
Renormalization of the isovector /πN amplitude in pionic atoms
Friedman, E.; Gal, A.
2003-08-01
The extraction of the isovector s-wave πN amplitude from pionic atoms is studied with special emphasis on uncertainties and their dependence on the assumptions made regarding the neutron density distributions in nuclei and on the size of the data base used. Only 'global' analyses of pionic-atom data reveal a discrepancy between the extracted isovector s-wave πN amplitude b1=(-0.108±0.007) mπ-1 and its free πN counterpart b 1free=-0.0885 +0.0010-0.0021 m π-1, where the uncertainty in the neutron densities is included in the error analysis. The role of 'deeply bound' pionic atom states is discussed and the reason for failure of these states to provide new information is explained.
On the determination of the pion effective mass in nuclei from pionic atoms
Friedman, E.; Gal, A.
1998-07-01
The binding energies of the deeply bound 1s and 2p states in pionic atoms of 207Pb, recently established experimentally in the 208Pb(d,3He) reaction, have been used by several groups to derive the pion effective mass in nuclear matter. We show that these binding energies are fully consistent with `normal' pionic atoms and that the real part of the pion-nucleus potential at the center of 207Pb is 28+/-3 MeV and not 20 MeV as suggested previously.
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...
Testing in-medium πN dynamics on pionic atoms
Friedman, E.; Gal, A.
2014-08-01
A general algorithm for handling the energy dependence of meson-nucleon amplitudes in the nuclear medium has been recently applied to antikaons and to eta mesons. Here we test this approach on πN amplitudes in pionic atoms where direct comparison can be made with ample experimental results. Applying this algorithm to a large-scale fit of 100 pionic-atom data points across the periodic table, which also include the ‘deeply-bound' states in Sn and Pb, reaffirms earlier conclusions on the density-dependent renormalization of the πN threshold isovector amplitude b1, or equivalently the renormalization of the pion decay constant fπ in the nuclear medium.
Testing chiral dynamics in pionic atoms
Friedman, E.; Gal, A.
2004-01-01
The energy dependence of chirally expanded πN isoscalar and isovector amplitudes b0(E) and b1(E), respectively, for zero-momentum off-shell pions near threshold, is used to impose the minimal substitution requirement E→E-VC on the properly constructed pion optical potential within a large-scale fit to 100 pionic-atom data across the periodic table which also include the recently established 'deeply bound' pionic atoms of Pb and Sn. This fit cannot be reconciled with the well-known free-space values of the πN threshold amplitudes. In contrast, introducing the empirically known energy dependence for on-shell pions leads to a better fit and to satisfactory values for the πN threshold amplitudes. The difference between these two approaches is briefly discussed.
K¯ nuclear bound states in a dynamical model
Mareš, J.; Friedman, E.; Gal, A.
2006-05-01
A comprehensive data base of K-atom level shifts and widths is re-analyzed in order to study the density dependence of the K¯-nuclear optical potential. Significant departure from a tρ form is found only for ρ(r)/ρ ≲ 0.2 and extrapolation to nuclear-matter density ρ yields an attractive potential, about 170 MeV deep. Partial restoration of chiral symmetry compatible with pionic atoms and low-energy pion-nuclear data plays no role at the relevant low-density regime, but this effect is not ruled out at densities of order ρ and beyond. K¯-nuclear bound states are generated across the periodic table self consistently, using a relativistic mean-field model Lagrangian which couples the K¯ to the scalar and vector meson fields mediating the nuclear interactions. The reduced phase space available for K¯ absorption from these bound states is taken into account by adding an energy-dependent imaginary term which underlies the corresponding K¯-nuclear level widths, with a strength required by fits to the atomic data. Substantial polarization of the core nucleus is found for light nuclei, and the binding energies and widths calculated in this dynamical model differ appreciably from those calculated for a static nucleus. A wide range of binding energies is spanned by varying the K¯ couplings to the meson fields. Our calculations provide a lower limit of Γ=50±10 MeV on the width of nuclear bound states for K¯-binding energy in the range B˜100-200 MeV. Comments are made on the interpretation of the FINUDA experiment at DAΦNE which claimed evidence for deeply bound Kpp states in light nuclei.
Schulz, Marc Daniel; Dusuel, Sébastien; Vidal, Julien
2016-11-01
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.
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.
Eta nuclear bound states revisited
Friedman, E; Mareš, J
2013-01-01
The strong energy dependence of the s-wave eta-N scattering amplitude at and below threshold, as evident in coupled-channels K-matrix fits and chiral models that incorporate the S11 N*(1535) resonance, is included self consistently in eta-nuclear bound state calculations. This approach, applied recently in calculations of kaonic atoms and Kbar-nuclear bound states, is found to impose stronger constraints than ever on the onset of eta-nuclear binding, with a minimum value of Re a_{eta N} approximately 0.9 fm required to accommodate an eta-4He bound state. Binding energies and widths of eta-nuclear states are calculated within several underlying eta-N models for nuclei across the periodic table, including eta-25Mg for which some evidence was proposed in a recent COSY experiment.
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.
Boosting equal time bound states
Dietrich, Dennis D; Jarvinen, Matti
2012-01-01
We present an explicit and exact boost of a relativistic bound state defined at equal time of the constituents in the Born approximation (lowest order in hbar). To this end, we construct the Poincar\\'e generators of QED and QCD in D=1+1 dimensions, using Gauss' law to express A^0 in terms of the fermion fields in A^1=0 gauge. We determine the fermion-antifermion bound states in the Born approximation as eigenstates of the time and space translation generators P^0 and P^1. The boost operator is combined with a gauge transformation so as to maintain the gauge condition A^1=0 in the new frame. We verify that the boosted state remains an eigenstate of P^0 and P^1 with appropriately transformed eigenvalues and determine the transformation law of the equal-time, relativistic wave function. The shape of the wave function is independent of the CM momentum when expressed in terms of a variable, which is quadratically related to the distance x between the fermions. As a consequence, the Lorentz contraction of the wave ...
Asymmetric dark matter bound state
Bi, Xiao-Jun; Kang, Zhaofeng; Ko, P.; Li, Jinmian; Li, Tianjun
2017-02-01
We propose an interesting framework for asymmetric scalar dark matter (ADM), which has novel 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 a 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 b ¯. The resulting signature at the LHC depends on the decays of X . In this paper we consider a case of particular interest: p p →b b ¯ +ADMonium followed by ADMonium→2 X →2 e+e- where the electrons are identified as (un)converted photons. It may provide a competitive explanation to heavy di-photon resonance searches at the LHC.
Hsu, Chia Wei; Zhen, Bo; Stone, A. Douglas; Joannopoulos, John D.; Soljačić, Marin
2016-09-01
Bound states in the continuum (BICs) are waves that remain localized even though they coexist with a continuous spectrum of radiating waves that can carry energy away. Their very existence defies conventional wisdom. Although BICs were first proposed in quantum mechanics, they are a general wave phenomenon and have since been identified in electromagnetic waves, acoustic waves in air, water waves and elastic waves in solids. These states have been studied in a wide range of material systems, such as piezoelectric materials, dielectric photonic crystals, optical waveguides and fibres, quantum dots, graphene and topological insulators. In this Review, we describe recent developments in this field with an emphasis on the physical mechanisms that lead to BICs across seemingly very different materials and types of waves. We also discuss experimental realizations, existing applications and directions for future work.
Bound anionic states of adenine
Energy Technology Data Exchange (ETDEWEB)
Haranczyk, Maciej; Gutowski, Maciej S; Li, Xiang; Bowen, Kit H
2007-03-20
Anionic states of nucleic acid bases are involved in DNA damage by low-energy electrons and in charge transfer through DNA. Previous gas phase studies of free, unsolvated nucleic acid base parent anions probed only dipole-bound states, which are not present in condensed phase environments, but did not observe valence anionic states, which for purine bases, are thought to be adiabatically unbound. Contrary to this expectation, we have demonstrated that some thus far ignored tautomers of adenine, which result from enamine-imine transformations, support valence anionic states with electron vertical detachment energies as large as 2.2 eV, and at least one of these anionic tautomers is adiabatically bound. Moreover, we predict that the new anionic tautomers should also dominate in solutions and should be characterized by larger values of electron vertical detachment energy than the canonical valence anion. All of the new-found anionic tautomers might be formed in the course of dissociative electron attachment followed by a hydrogen atom attachment to a carbon atom, and they might affect the structure and properties of DNA and RNA exposed to low-energy electrons. The discovery of these valence anionic states of adenine was facilitated by the development of: (i) a new experimental method for preparing parent anions of nucleic acid bases for photoelectron experiments, and (ii) a new combinatorial/ quantum chemical approach for identification of the most stable tautomers of organic molecules. The computational portion of this work was supported by the: (i) Polish State Committee for Scientific Research (KBN) Grants: DS/8000-4-0140-7 (M.G.) and N204 127 31/2963 (M.H.), (ii) European Social Funds (EFS) ZPORR/2.22/II/2.6/ARP/U/2/05 (M.H.), and (iii) US DOE Office of Biological and Environmental Research, Low Dose Radiation Research Program (M.G.). M.H. holds the Foundation for Polish Science (FNP) award for young scientists. The calculations were performed at the Academic
Precision spectroscopy of pionic atoms and chiral symmetry in nuclei
Directory of Open Access Journals (Sweden)
Itahashi Kenta
2016-01-01
Full Text Available We conduct an experimental project to make spectroscopy of deeply bound pionic atoms systematically over wide range of nuclei. We aim at studying the strong interaction in the low energy region, which has close connection to spontaneous chiral symmetry breaking and its partial restoration in nuclear matter. First experimental results show improved spectral resolution and much better statistical sensitivity than previous experiments. Present status of the experiment is reported.
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.
Pionic fusion in light-ion systems
Joulaeizadeh, L.; Gasparic, I.; Amir-Ahmadi, H. R.; Bacelar, J.; Caplar, R.; Eslami-Kalantari, M.; Kalantar-Nayestanaki, N.; Löhner, H.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Ramazani-Moghaddam-Arani, A. A.; Shende, S. V.; Stephan, E.
2011-01-01
The role of pions in the nuclear interaction has been studied in pionic fusion experiments using the AGOR accelerator facility at KVI. Pionic fusion is a highly coherent process in which two nuclei fuse to a united nucleus and the available centre-of-mass (C.M.) energy is emitted through the pion ch
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.
Lower Bounds of Concurrence for Multipartite States
Zhu, Xue-Na; Fei, Shao-Ming
2012-01-01
We study the entanglement of multipartite quantum states. Some lower bounds of the multipartite concurrence are reviewed. We further present more effective lower bounds for detecting and qualifying entanglement, by establishing functional relations between the concurrence and the generalized partial transpositions of the multipartite systems.
Density dependence of the /s-wave repulsion in pionic atoms
Friedman, E.
2002-11-01
Several mechanisms of density dependence of the s-wave repulsion in pionic atoms, beyond the conventional model, are tested by parameter fits to a large (106 points) set of data from 16O to 238U, including 'deeply bound' states in 205Pb. Special attention is paid to the proper choice of nuclear density distributions. A density-dependent isovector scattering amplitude suggested recently by Weise to result from a density dependence of the pion decay constant is introduced and found to account for most of the so-called anomalous repulsion. The presence of such an effect might indicate partial chiral symmetry restoration in dense matter. The anomalous repulsion is fully accounted for when an additional relativistic impulse approximation term is included in the potential.
Irreversibility for all bound entangled states
Yang, D; Horodecki, R; Synak-Radtke, B; Yang, Dong; Horodecki, Michal; Horodecki, Ryszard; Synak-Radtke, Barbara
2005-01-01
We derive a new inequality for entanglement for a mixed four-partite state. Employing this inequality, we present a one-shot lower bound for entanglement cost and prove that entanglement cost is strictly larger than zero for any entangled state. We demonstrate that irreversibility occurs in the process of formation for all non-distillable entangled states. In this way we solve a long standing problem, of how "real" is entanglement of bound entangled states. Using the new inequality we also prove impossibility of local-cloning and local-deleting of a known entangled state.
Bound States in Boson Impurity Models
Shi, Tao; Wu, Ying-Hai; González-Tudela, A.; Cirac, J. I.
2016-04-01
The formation of bound states involving multiple particles underlies many interesting quantum physical phenomena, such as Efimov physics or superconductivity. In this work, we show the existence of an infinite number of such states for some boson impurity models. They describe free bosons coupled to an impurity and include some of the most representative models in quantum optics. We also propose a family of wave functions to describe the bound states and verify that it accurately characterizes all parameter regimes by comparing its predictions with exact numerical calculations for a one-dimensional tight-binding Hamiltonian. For that model, we also analyze the nature of the bound states by studying the scaling relations of physical quantities, such as the ground-state energy and localization length, and find a nonanalytical behavior as a function of the coupling strength. Finally, we discuss how to test our theoretical predictions in experimental platforms, such as photonic crystal structures and cold atoms in optical lattices.
Family of nonlocal bound entangled states
Yu, Sixia; Oh, C. H.
2017-03-01
Bound entanglement, being entangled yet not distillable, is essential to our understanding of the relations between nonlocality and entanglement besides its applications in certain quantum information tasks. Recently, bound entangled states that violate a Bell inequality have been constructed for a two-qutrit system, disproving a conjecture by Peres that bound entanglement is local. Here we construct this kind of nonlocal bound entangled state for all finite dimensions larger than two, making possible their experimental demonstration in most general systems. We propose a Bell inequality, based on a Hardy-type argument for nonlocality, and a steering inequality to identify their nonlocality. We also provide a family of entanglement witnesses to detect their entanglement beyond the Bell inequality and the steering inequality.
η-nuclear bound states revisited
Friedman, E.; Gal, A.; Mareš, J.
2013-10-01
The strong energy dependence of the s-wave ηN scattering amplitude at and below threshold, as evident in coupled-channels K-matrix fits and chiral models that incorporate the S11N* (1535) resonance, is included self-consistently in η-nuclear bound-state calculations. This approach, applied recently in calculations of kaonic atoms and Kbar-nuclear bound states, is found to impose stronger constraints than ever on the onset of η-nuclear binding, with a minimum value of ReaηN ≈ 0.9 fm required to accommodate an η-4He bound state. Binding energies and widths of η-nuclear states are calculated within several underlying ηN models for nuclei across the periodic table, including Mg25η for which some evidence was proposed in a recent COSY experiment.
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...
Institute of Scientific and Technical Information of China (English)
侯春风; 周忠祥; 袁保红
1999-01-01
研究了在具有Coulomb势的N维Enclidean空间中运动的相对论性无自旋粒子的束缚态,给出了粒子的能级及相应径向波函数.所得结果适用于N维π介子原子.%Bound states of a relativistic spinless particle moving in an N-dimensional (N≥2) Euclid space with Coulomb potential are investigated, the energy levels and corresponding normalized radial wave-functions expressed in terms of confluent hypergeometric function are given. The results are applicable to an N-dimensional pionic atom.
Method for laser spectroscopy of metastable pionic helium atoms
Energy Technology Data Exchange (ETDEWEB)
Hori, M., E-mail: Masaki.Hori@mpq.mpg.de; Sótér, A.; Aghai-Khozani, H. [Max-Planck-Institut für Quantenoptik (Germany); Barna, D. [CERN (Switzerland); Dax, A. [Paul Scherrer Institut (Switzerland); Hayano, R. S.; Murakami, Y.; Yamada, H. [University of Tokyo, Department of Physics (Japan)
2015-08-15
The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic helium atoms using the high-intensity π{sup −} 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{sup −} 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.
Nuclear internal conversion between bound atomic states
Chemin, J. F.; Harston, M. R.; Karpeshin, F. F.; Carreyre, J.; Attallah, F.; Aleonard, M. M.; Scheurer, J. N.; Boggaert, G.; Grandin, J. R.; Trzhaskovskaya, M. B.
2003-01-01
We present experimental and theoretical results for rate of decay of the (3/2)+ isomeric state in 125Te versus the ionic charge state. For charge state larger than 44 the nuclear transition lies below the threshold for emission of a K-shell electron into the continuum with the result that normal internal conversion is energetically forbiden. Rather surprisingly, for the charge 45 and 46 the lifetime of the level was found to have a value close to that in neutral atoms. We present direct evidence that the nuclear transition could still be converted but without the emission of the electron into the continuum, the electron being promoted from the K-shell to an other empty bound state lying close to the continuum. We called this process BIC. The experimental results agree whith theoretical calculations if BIC resonances are taken into account. This leads to a nuclear decay constant that is extremely sensitive to the precise initial state and simple specification of the charge state is no longer appropriate. The contribution to decay of the nucleus of BIC has recently been extended to the situation in which the electron is promoted to an intermediate filled bound state (PFBIC) with an apparent violation of the Pauli principle. Numerical results of the expected dependence of PFBIC on the charge state will be presented for the decay of the 77.351 keV level in 197Au.
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.)
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.
Nuclear dynamics of K¯ bound states
Mareš, J.; Friedman, E.; Gal, A.
2006-07-01
K¯ nuclear bound states were generated dynamically within a relativistic mean field (RMF) model. Substantial polarization of the core nucleus was found for light nuclei. The behavior of the dynamically calculated width ΓK¯ as function of the K¯ binding energy was studied. A lower limit of ΓK¯ ˜ 35 - 45 MeV for 1s K¯ nuclear states in light nuclei such as 12C was placed on the width expected for deep binding in the range B K¯ ˜ 100 - 200 MeV.
Pionic fusion in light-ion systems
Energy Technology Data Exchange (ETDEWEB)
Joulaeizadeh, L., E-mail: l.joulaeizadeh@tudelft.n [KVI, University of Groningen, Groningen (Netherlands); Gasparic, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Amir-Ahmadi, H.R.; Bacelar, J. [KVI, University of Groningen, Groningen (Netherlands); Caplar, R. [Rudjer Boskovic Institute, Zagreb (Croatia); Eslami-Kalantari, M.; Kalantar-Nayestanaki, N.; Loehner, H.; Mardanpour, H.; Messchendorp, J.G.; Moeini, H.; Ramazani-Moghaddam-Arani, A.; Shende, S.V. [KVI, University of Groningen, Groningen (Netherlands); Stephan, E. [Institute of Physics, University of Silesia, Katowice (Poland)
2011-01-03
The role of pions in the nuclear interaction has been studied in pionic fusion experiments using the AGOR accelerator facility at KVI. Pionic fusion is a highly coherent process in which two nuclei fuse to a united nucleus and the available centre-of-mass (C.M.) energy is emitted through the pion channel. The examined reactions were {sup 4}He({sup 3}He, {pi}{sup 0}){sup 7}Be and {sup 6}Li({sup 4}He, {pi}{sup 0}){sup 10}B{sup *} and both reactions were performed at C.M. energies about 10 MeV above the coherent pion production threshold. Here, the experimental results for the {sup 6}Li({sup 4}He, {pi}{sup 0}){sup 10}B{sup *} reaction will be presented and discussed. In order to provide sensitivity to the full dynamics and relevant processes involved in the pionic fusion reaction, almost the full angular distribution of neutral pions has been determined. In a phenomenological analysis, the contributions of Legendre polynomials to reproduce the behaviour of the angular distribution have been studied. The results of this analysis confirm the importance of the clustering correlations for the {sup 6}Li({sup 4}He, {pi}{sup 0}){sup 10}B{sup *} reaction. The mass dependence of the pionic fusion reaction is in agreement with the results of the existing models extrapolated to this reaction.
Pionic fusion in light-ion systems
Joulaeizadeh, L.; Gašparić, I.; Amir-Ahmadi, H. R.; Bacelar, J.; Čaplar, R.; Eslami-Kalantari, M.; Kalantar-Nayestanaki, N.; Löhner, H.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Ramazani-Moghaddam-Arani, A.; Shende, S. V.; Stephan, E.
2011-01-01
The role of pions in the nuclear interaction has been studied in pionic fusion experiments using the AGOR accelerator facility at KVI. Pionic fusion is a highly coherent process in which two nuclei fuse to a united nucleus and the available centre-of-mass (C.M.) energy is emitted through the pion channel. The examined reactions were 4He(3He, π0)7Be and 6Li(4He, π0)10B* and both reactions were performed at C.M. energies about 10 MeV above the coherent pion production threshold. Here, the experimental results for the 6Li(4He, π0)10B* reaction will be presented and discussed. In order to provide sensitivity to the full dynamics and relevant processes involved in the pionic fusion reaction, almost the full angular distribution of neutral pions has been determined. In a phenomenological analysis, the contributions of Legendre polynomials to reproduce the behaviour of the angular distribution have been studied. The results of this analysis confirm the importance of the clustering correlations for the 6Li(4He, π0)10B* reaction. The mass dependence of the pionic fusion reaction is in agreement with the results of the existing models extrapolated to this reaction.
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.
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. 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.
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 ...
On Aharonov-Casher bound states
Silva, E. O.; Andrade, F. M.; Filgueiras, C.; Belich, H.
2013-04-01
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 ∇ṡ 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.
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.)
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.
Hyperquarks and bosonic preon bound states
Schmid, Michael L.; Buchmann, Alfons J.
2009-11-01
In a model in which leptons, quarks, and the recently introduced hyperquarks are built up from two fundamental spin-(1)/(2) preons, the standard model weak gauge bosons emerge as preon bound states. In addition, the model predicts a host of new composite gauge bosons, in particular, those responsible for hyperquark and proton decay. Their presence entails a left-right symmetric extension of the standard model weak interactions and a scheme for a partial and grand unification of nongravitational interactions based on, respectively, the effective gauge groups SU(6)P and SU(9)G. This leads to a prediction of the Weinberg angle at low energies in good agreement with experiment. Furthermore, using evolution equations for the effective coupling strengths, we calculate the partial and grand unification scales, the hyperquark mass scale, as well as the mass and decay rate of the lightest hyperhadron.
Hyperquarks and bosonic preon bound states
Schmid, Michael L
2013-01-01
In a model in which leptons, quarks, and the recently introduced hyperquarks are built up from two fundamental spin 1/2 preons, the standard model weak gauge bosons emerge as preon bound states. In addition, the model predicts a host of new composite gauge bosons, in particular those responsible for hyperquark and proton decay. Their presence entails a left-right symmetric extension of the standard model weak interactions and a scheme for a partial and grand unification of nongravitational interactions based on respectively the effective gauge groups SU(6)_P and SU(9)_G. This leads to a prediction of the Weinberg angle at low energies in good agreement with experiment. Furthermore, using evolution equations for the effective coupling strengths, we calculate the partial and grand unification scales, the hyperquark mass scale, as well as the mass and decay rate of the lightest hyperhadron.
Topological magnon bound-states in quantum Heisenberg chains
Qin, Xizhou; Ke, Yongguan; Zhang, Li; Lee, Chaohong
2016-01-01
It is still an outstanding challenge to characterize and understand the topological features of strongly correlated states such as bound-states in interacting multi-particle quantum systems. Recently, bound states of elementary spin waves (magnons) in quantum magnets have been experimentally observed in quantum Heisenberg chains comprising ultracold Bose atoms in optical lattices. Here, we explore an unprecedented topological state called topological magnon bound-state in the quantum Heisenberg chain under cotranslational symmetry. We find that the cotranslational symmetry allows us to formulate a direct topological invariant for the multi-particle quantum states, which can be used to characterize the topological features of multi-magnon excitations. We calculate energy spectra, density distributions, correlations and topological invariants of the two-magnon bound-states and show the existence of topological magnon bound-states. Our study not only opens a new prospect to pursue topological bound-states, but a...
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...
Review of the N-quantum Approach to Bound States
Greenberg, O W
2010-01-01
We describe a method of solving quantum field theories using operator techniques based on the expansion of interacting fields in terms of asymptotic fields. For bound states, we introduce an asymptotic field for each (stable) bound state. We choose the nonrelativistic hydrogen atom as an example to illustrate the method. Future work will apply this N-quantum approach to relativistic theories that include bound states in motion.
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...
Relativistic bound-state equations for fermions with instantaneous interactions
Suttorp, L.G.
1979-01-01
Three types of relativistic bound-state equations for a fermion pair with instantaneous interaction are studied, viz., the instantaneous Bethe-Salpeter equation, the quasi-potential equation, and the two-particle Dirac equation. General forms for the equations describing bound states with arbitrary
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.
Ultrarelativistic bound states in the shallow spherical well
Zaba, Mariusz
2016-01-01
We determine approximate eigenvalues and eigenfunctions shapes for bound states in the $3D$ shallow spherical ultrarelativistic well. Existence thresholds for the ground state and first excited states are identified, both in the purely radial and orbitally nontrivial cases. This contributes to an understanding of how energy may be stored or accumulated in the form of bound states of Schr\\"odinger - type quantum systems that are devoid of any mass.
Search for exotic baryons in double radiative capture on pionic hydrogen
Energy Technology Data Exchange (ETDEWEB)
Zolnierczuk, P.A. [University of Kentucky, Lexington, KY 40506 (United States); Armstrong, D.S. [College of William and Mary, Williamsburg, VA 23187 (United States); Christy, E. [University of Kentucky, Lexington, KY 40506 (United States); Clark, J.H.D. [College of William and Mary, Williamsburg, VA 23187 (United States); Gorringe, T.P. [University of Kentucky, Lexington, KY 40506 (United States)]. E-mail: gorringe@server1.pa.uky.edu; Hasinoff, M.D. [University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Kovash, M.A. [University of Kentucky, Lexington, KY 40506 (United States); Tripathi, S. [University of Kentucky, Lexington, KY 40506 (United States); Wright, D.H. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)
2004-09-09
We report a search for low-lying exotic baryons via double radiative capture on pionic hydrogen. The data were collected at the TRIUMF cyclotron using the RMC spectrometer by detecting gamma-ray pairs from pion stops in liquid hydrogen. We found no evidence to support an earlier claim for exotic baryons of masses 1004 and 1044 MeV/c2, and set upper limits on exotic baryon mediated capture of 3x10-6 and 4x10-6, respectively. We also obtained bounds on the couplings between exotic baryons and ordinary nucleons.
Mass spectrum bound state systems with relativistic corrections
Energy Technology Data Exchange (ETDEWEB)
Dineykhan, M; Zhaugasheva, S A [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Toinbaeva, N Sh; Jakhanshir, A [al-Farabi Kazak National University, 480012 Almaty (Kazakhstan)
2009-07-28
Based on the investigation of the asymptotic behaviour of the polarization loop function for charged n scalar particles in an external gauge field, we determine the interaction Hamiltonian including relativistic corrections. The mass spectrum of the bound state is analytically derived. The mechanism for arising of the constituent mass of the relativistic bound-state forming particles is explained. The mass and the constituent mass of the two-, three- and n-body relativistic bound states are calculated taking into account relativistic corrections. The corrections arising due to the one- and two-loop electron polarization to the energy spectrum of muonic hydrogen with orbital and radial excitations are calculated.
Second Bound State of Biexcitons in Quantum Dots
Institute of Scientific and Technical Information of China (English)
XIE Wen-Eang
2003-01-01
The second bound state of the biexcitons in a quantum dot, with orbital angular momentum L = 1, is reported. By using the method of few-body physics, the binding energy spectra of the second bound state of a biexciton in a GaAs quantum dot with a parabolic confinement have been calculated as a function of the electron-to-hole mass ratio and the quantum dot size. The fact that the biexcitons have a second bound state may aid in the better understanding of their binding mechanism.
Entanglement bounds for squeezed non-symmetric thermal state
Jiang, L
2003-01-01
I study the three parameters bipartite quantum Gaussian state called squeezed asymmetric thermal state, calculate Gaussian entanglement of formation analytically and the up bound of relative entropy of entanglement, compare them with coherent information of the state. Based on the result obtained, it is anticipated that hashing inequality is not violated for squeezed non-symmetric thermal state.
Quasi-bound states in strained graphene
Bahamon, Dario; Qi, Zenan; Park, Harold; Pareira, Vitor; Campbell, David
In this work, we explore the possibility of manipulating electronic states in graphene nanostructures by mechanical means. Specifically, we use molecular dynamics and tight-binding models to access the electronic and transport properties of strained graphene nanobubbles and graphene kirigami. We establish that low energy electrons can be confined in the arms of the kirigami and within the nanobubbles; under different load conditions the coupling between confined states and continuous states is modified creating different conductance line-shapes.
Bound states of two-dimensional relativistic harmonic oscillators
Institute of Scientific and Technical Information of China (English)
Qiang Wen-Chao
2004-01-01
We give the exact normalized bound state wavefunctions and energy expressions of the Klein-Gordon and Dirac equations with equal scalar and vector harmonic oscillator potentials in the two-dimensional space.
On the bound states for the Aharonov-Casher systems
Silva, E O; Belich, H; Filgueiras, C
2012-01-01
The bound states for the Aharonov-Casher problem is considered. According to the Hagen's work on the exact equivalence between spin-1/2 Aharonov-Bohm and Aharonov-Casher effects, is known that the $\\boldsymbol{\
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.
Narrow deeply bound K- and p atomic states
Friedman, E.; Gal, A.
2000-01-01
Examples of recently predicted narrow `deeply bound' K- and p atomic states are shown. The saturation of widths for strong absorptive potentials due to the induced repulsion, and the resulting suppression of atomic wave functions within the nucleus, are demonstrated. Production reactions for K- atomic states using φ(1020) decay, and the (p,p) reaction for p atomic states, are discussed.
NOON states via a quantum walk of bound particles
Compagno, Enrico; Banchi, Leonardo; Gross, Christian; Bose, Sougato
2017-01-01
Tight-binding lattice models allow the creation of bound composite objects which, in the strong-interacting regime, are protected against dissociation. We show that a local impurity in the lattice potential can generate a coherent split of an incoming bound particle wave packet which consequently produces a NOON state between the endpoints. This is nontrivial because, when finite lattices are involved, edge-localization effects render challenging their use for nonclassical state generation and information transfer. We derive an effective model to describe the propagation of bound particles in a Bose-Hubbard chain. We introduce local impurities in the lattice potential to inhibit localization effects and to split the propagating bound particle, thus enabling the generation of distant NOON states. We analyze how minimal engineering transfer schemes improve the transfer fidelity and we quantify the robustness to typical decoherence effects in optical lattice implementations. Our scheme potentially has an impact on quantum-enhanced atomic interferometry in a lattice.
Effects of QCD bound states on dark matter relic abundance
Liew, Seng Pei; Luo, Feng
2017-02-01
We study scenarios where there exists an exotic massive particle charged under QCD in the early Universe. We calculate the formation and dissociation rates of bound states formed by pairs of these particles, and apply the results in dark matter (DM) coannihilation scenarios, including also the Sommerfeld effect. We find that on top of the Sommerfeld enhancement, bound-state effects can further significantly increase the largest possible DM masses which can give the observed DM relic abundance, by ˜ 30-100% with respect to values obtained by considering the Sommerfeld effect only, for the color triplet or octet exotic particles we consider. In particular, it indicates that the Bino DM mass in the right-handed stop-Bino coannihilation scenario in the Minimal Supersymmetric extension of the Standard Model (MSSM) can reach ˜ 2.5 TeV, even though the potential between the stop and antistop prior to forming a bound state is repulsive. We also apply the bound-state effects in the calculations of relic abundance of long-lived or metastable massive colored particles, and discuss the implications on the BBN constraints and the abundance of a super-weakly interacting DM. The corrections for the bound-state effect when the exotic massive colored particles also carry electric charges, and the collider bounds are also discussed.
Bound and continuum vibrational states of the bifluoride anion
Špirko, V.; Šindelka, M.; Shirsat, R. N.; Leszczynski, J.
2003-07-01
The energies of the bound vibrational states and energy density spectra of the continuum vibrational states of FHF - are calculated, 'exactly' and 'adiabatically', using a new ab initio (CCSD(T)) potential energy surface. Statistical properties of the bound states are probed in terms of the density of states and nearest neighbor level spacing distributions (NNSD). Importantly, the approximate 'adiabatic' densities coincide nearly quantitatively with their 'exact' counterparts. A quantitative fitting of the NNSDs is achieved with a new empirical modification of the Wigner distribution.
Floquet bound states around defects and adatoms in graphene
Lovey, D. A.; Usaj, Gonzalo; Foa Torres, L. E. F.; Balseiro, C. A.
2016-06-01
Recent studies have focused on laser-induced gaps in graphene which have been shown to have a topological origin, thereby hosting robust states at the sample edges. While the focus has remained mainly on these topological chiral edge states, the Floquet bound states around defects lack a detailed study. In this paper we present such a study covering large defects of different shape and also vacancy-like defects and adatoms at the dynamical gap at ℏ Ω /2 (ℏ Ω being the photon energy). Our results, based on analytical calculations as well as numerics for full tight-binding models, show that the bound states are chiral and appear in a number which grows with the defect size. Furthermore, while the bound states exist regardless of the type of the defect's edge termination (zigzag, armchair, mixed), the spectrum is strongly dependent on it. In the case of top adatoms, the bound state quasienergies depend on the adatoms energy. The appearance of such bound states might open the door to the presence of topological effects on the bulk transport properties of dirty graphene.
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.
Internal conversion to bound final states in 125Te
Harston, M. R.; Carreyre, T.; Chemin, J. F.; Karpeshin, F.; Trzhaskovskaya, M. B.
2000-08-01
Theoretical results are presented for rate of decay of the 3/2+ isomeric nuclear state of 125Te by excitation of atomic electrons to bound states in the ions Te 45+ and Te 46+. In these ions the nuclear transition energy lies just below the threshold for emission of a K-shell electron to the continuum with the result that normal K-shell internal conversion is energetically forbidden. However recent experimental results indicate that excitation of K-shell electrons is still significant in these ions. The theoretical results presented here for internal conversion to bound final states are in quantitative agreement with experiment and thereby confirm the contribution of near-resonant electron-nucleus transitions involving a bound final state.
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.
Two-body bound state problem and nonsingular scattering equations
Energy Technology Data Exchange (ETDEWEB)
Bartnik, E.A.; Haberzettl, H.; Sandhas, W.
1986-11-01
We present a new momentum space approach to the two-body problem in partial waves. In contrast to the usual momentum space approaches, we treat the bound state case with the help of an inhomogeneous integral equation which possesses solutions for all (negative) energies. The bound state energies and corresponding wave functions are identified by an additional condition. This procedure straightforwardly leads to a nonsingular formulation of the scattering problem in terms of essentially the same equation and thus unifies the descriptions of both energy regimes. We show that the properties of our momentum-space approach can be understood in terms of the so-called regular solution of the Schroedinger equation in position space. The unified description of the bound state and scattering energy regimes in terms of one single, real, and manifestly nonsingular equation allows us to construct an exact representation of the two-body off-shell T matrix in which all the bound state pole and scattering cut information is contained in one single separable term, the remainder being real, nonsingular, and vanishing half on-shell. Such a representation may be of considerable advantage as input in three-body Faddeev-type integral equations. We demonstrate the applicability of our method by calculating bound state and scattering data for the two-nucleon system with the s-wave Malfliet--Tjon III potential.
Bound states in open coupled asymmetrical waveguides and quantum wires
Amore, Paolo; Terrero-Escalante, Cesar A
2011-01-01
The behavior of bound states in asymmetric cross, T and L shaped configurations is considered. Because of the symmetries of the wavefunctions, the analysis can be reduced to the case of an electron localized at the intersection of two orthogonal crossed wires of different width. Numerical calculations show that the fundamental mode of this system remains bound for the widths that we have been able to study directly; moreover, the extrapolation of the results obtained for finite widths suggests that this state remains bound even when the width of one arm becomes infinitesimal. We provide a qualitative argument which explains this behavior and that can be generalized to the lowest energy states in each symmetry class. In the case of odd-odd states of the cross we find that the lowest mode is bounded when the width of the two arms is the same and stays bound up to a critical value of the ratio between the widths; in the case of the even-odd states we find that the lowest mode is unbound up to a critical value of...
Search for bound-state electron+positron pair decay
Bosch, F.; Hagmann, S.; Hillenbrand, P.-M.; Lane, G. J.; Litvinov, Yu. A.; Reed, M. W.; Sanjari, M. S.; Stöhlker, Th.; Torilov, S. Yu.; Tu, X. L.; Walke, P. M.
2016-09-01
The heavy ion storage rings coupled to in-flight radioactive-ion beam facilities, namely the ability to produce and store for extended periods of time radioactive nuclides in high atomic charge states, for the searchof yet unobserved decay mode - bound-state electron-positron pair decay.
Photodisintegration of a Bound State on the Torus
Meyer, Harvey B
2012-01-01
In this article the cross-section for the photodisintegration of a bound state is expressed, order by order in the multipole expansion, in terms of matrix elements between states living on the three-dimensional torus. The motivation is to make the process amenable to Monte-Carlo simulations. The case of the deuteron is discussed.
Bound state techniques to solve the multiparticle scattering problem
Carbonell, J; Fonseca, A C; Lazauskas, R
2013-01-01
Solution of the scattering problem turns to be very difficult task both from the formal as well as from the computational point of view. If the last two decades have witnessed decisive progress in ab initio bound state calculations, rigorous solution of the scattering problem remains limited to A$\\leq$4 case. Therefore there is a rising interest to apply bound-state-like methods to handle non-relativistic scattering problems. In this article the latest theoretical developments in this field are reviewed. Five fully rigorous methods will be discussed, which address the problem of nuclear collisions in full extent (including the break-up problem) at the same time avoiding treatment of the complicate boundary conditions or integral kernel singularities. These new developments allows to use modern bound-state techniques to advance significantly rigorous solution of the scattering problem.
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.
Bounding the persistency of the nonlocality of W states
Diviánszky, Péter; Trencsényi, Réka; Bene, Erika; Vértesi, Tamás
2016-04-01
The nonlocal properties of the W states are investigated under particle loss. By removing all but two particles from an N -qubit W state, the resulting two-qubit state is still entangled. Hence, the W state has high persistency of entanglement. We ask an analogous question regarding the persistency of nonlocality [see N. Brunner and T. Vértesi, Phys. Rev. A 86, 042113 (2012), 10.1103/PhysRevA.86.042113]. Namely, we inquire what is the minimal number of particles that must be removed from the W state so that the resulting state becomes local. We bound this value in function of N qubits by considering Bell nonlocality tests with two alternative settings per site. In particular, we find that this value is between 2 N /5 and N /2 for large N . We also develop a framework to establish bounds for more than two settings per site.
Force-producing ADP state of myosin bound to actin.
Wulf, Sarah F; Ropars, Virginie; Fujita-Becker, Setsuko; Oster, Marco; Hofhaus, Goetz; Trabuco, Leonardo G; Pylypenko, Olena; Sweeney, H Lee; Houdusse, Anne M; Schröder, Rasmus R
2016-03-29
Molecular motors produce force when they interact with their cellular tracks. For myosin motors, the primary force-generating state has MgADP tightly bound, whereas myosin is strongly bound to actin. We have generated an 8-Å cryoEM reconstruction of this state for myosin V and used molecular dynamics flexed fitting for model building. We compare this state to the subsequent state on actin (Rigor). The ADP-bound structure reveals that the actin-binding cleft is closed, even though MgADP is tightly bound. This state is accomplished by a previously unseen conformation of the β-sheet underlying the nucleotide pocket. The transition from the force-generating ADP state to Rigor requires a 9.5° rotation of the myosin lever arm, coupled to a β-sheet rearrangement. Thus, the structure reveals the detailed rearrangements underlying myosin force generation as well as the basis of strain-dependent ADP release that is essential for processive myosins, such as myosin V.
Flow Equations for N Point Functions and Bound States
Ellwanger, Ulrich
1994-01-01
We discuss the exact renormalization group or flow equation for the effective action and its decomposition into one particle irreducible N point functions. With the help of a truncated flow equation for the four point function we study the bound state problem for scalar fields. A combination of analytic and numerical methods is proposed, which is applied to the Wick-Cutkosky model and a QCD-motivated interaction. We present results for the bound state masses and the Bethe-Salpeter wave function. (Figs. 1-4 attached as separate uuencoded post-script files.)
Parity lifetime of bound states in a proximitized semiconductor nanowire
DEFF Research Database (Denmark)
Higginbotham, Andrew Patrick; Albrecht, Sven Marian; Kirsanskas, Gediminas
2015-01-01
superconductors but remain relatively unexplored in semiconductor-superconductor structures, which are now being intensely pursued in the context of topological superconductivity. To this end, we introduce a new physical system comprised of a gate-confined semiconductor nanowire with an epitaxially grown...... superconductor layer, yielding an isolated, proximitized nanowire segment. We identify Andreev-like bound states in the semiconductor via bias spectroscopy, determine the characteristic temperatures and magnetic fields for quasiparticle excitations, and extract a parity lifetime (poisoning time) of the bound...... state in the semiconductor exceeding 10 ms....
Helical bound states in the continuum of the edge states in two dimensional topological insulators
Energy Technology Data Exchange (ETDEWEB)
Sablikov, Vladimir A., E-mail: sablikov@gmail.com; Sukhanov, Aleksei A.
2015-09-04
We study bound states embedded into the continuum of edge states in two-dimensional topological insulators. These states emerge in the presence of a short-range potential of a structural defect coupled to the boundary. In this case the edge states flow around the defect and have two resonances in the local density of states. The bound state in continuum (BIC) arises due to an interference of the resonances when they are close to the degeneracy. We find the condition under which the BIC appears, study the spacial distribution of the electron density, and show that the BIC has a helical structure with an electron current circulating around the defect. - Highlights: • We find bound states in the continuum of edge states in 2D topological insulators. • The bound states are induced by an impurity potential and topological order. • The bound state in the continuum has a helical structure of spin and current density.
First direct proof of internal conversion between bound states
Carreyre, T.; Harston, M. R.; Aiche, M.; Bourgine, F.; Chemin, J. F.; Claverie, G.; Goudour, J. P.; Scheurer, J. N.; Attallah, F.; Bogaert, G.; Kiener, J.; Lefebvre, A.; Durell, J.; Grandin, J. P.; Meyerhof, W. E.; Phillips, W.
2000-08-01
We present direct evidence for the process of internal conversion between bound atomic states (BIC) when the binding energy of the converted electron becomes larger than the nuclear transition energy. This process has been proposed as an explanation of the measured, unexpectedly short lifetime of the first excited state of 125Te with charge state larger than 44+. We have detected the Kα x rays emitted in flight which follow the filling of the K-shell vacancy created by the bound internal conversion process, together with γ rays from Te ions in charge states ranging between 44+ and 48+. For Te45+ and Te46+, the comparison of the x-ray to γ-ray ratios with the theoretical calculations of the internal conversion coefficients including decay to bound atomic states, assuming Te ions in their ground electronic state, show poor agreement. The agreement becomes good if account is taken of BIC decay of excited initial states with different occupancies of the 2p1/2 and 2p3/2 subshells. In this situation, the half-life becomes sensitive to the precise initial state and simple specification of the charge state alone is no longer appropriate.
Directional detection of dark matter in universal bound states
Laha, Ranjan
2015-01-01
It has been suggested that several small-scale structure anomalies in $\\Lambda$CDM cosmology can be solved by strong self-interaction between dark matter particles. It was shown by Braaten and Hammer 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). Laha and Braaten 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.
ɛ-bounded state estimation for time-delay systems with bounded disturbances
Nam, P. T.; Pathirana, P. N.; Trinh, H.
2014-09-01
A new problem on ε-bounded functional state estimation for time-delay systems with unknown bounded disturbances is studied in this paper. In the presence of unknown bounded disturbances, the common assumption regarding the observer's matching condition is no longer required. In this regard, instead of achieving asymptotic convergence for the observer error, the error is now required to converge exponentially within a ball with a small radius ε > 0. This means that the estimate converges exponentially within an ε-bound of the true value. A general observer that utilises multiple-delayed output and input information is proposed. Sufficient conditions for the existence of the proposed observer are first given. We then employ an extended Lyapunov-Krasovskii functional which combines the delay-decomposition technique with a triple-integral term to study the ε-convergence problem of the observer error system. Moreover, the obtained results are shown to be more effective than the existing results for the cases with no disturbances and/or no time delay. Three numerical examples are given to illustrate the obtained results.
A Lorentz covariant approach to the bound state problem
Micu, L
2000-01-01
The relativistic equivalent of the Schr\\"odinger equation for a two particle bound state having the total angular momentum $S$ is written in the form of a Lorentz covariant set of equations (p_1^mu+p_2^mu+Omega^mu)Psi(p_1,p_2;P) chi_S(\\vec{p}_1,\\vec{p}_2)=P^mu Psi(p_1,p_2;P) chi_S(\\vec{p}_1,\\vec{p}_2) where the operators Omega^mu are the components of a 4-vector quasipotential. The solution of this set is a stationary function representing the distribution of spins and internal momenta in a reference frame where the momentum of the bound system is P^\\mu. The contribution of the operators Omega^mu to the bound state momentum is assumed to be the 4-momentum of a vacuum-like effective field entering the bound system as an independent component. It is shown that a state made of free quarks and of the effective field has definite mass and can be normalized like a single particle state. The generalization to the case of three or more particles is immediate.
The S-matrix of String Bound States
Arutyunov, Gleb
2008-01-01
We find the S-matrix which describes the scattering of two-particle bound states of the light-cone string sigma model on AdS5xS5. We realize the M-particle bound state representation of the centrally extended su(2|2) algebra on the space of homogeneous (super)symmetric polynomials of degree M depending on two bosonic and two fermionic variables. The scattering matrix S^{MN} of M- and N-particle bound states is a differential operator of degree M+N acting on the product of the corresponding polynomials. We require this operator to obey the invariance condition and the Yang-Baxter equation, and we determine it for the two cases M=1,N=2 and M=N=2. We show that the S-matrices found satisfy generalized physical unitarity, CPT invariance, parity transformation rule and crossing symmetry. Although the dressing factor as a function of four parameters x_1^+,x_1^-,x_2^+,x_2^- is universal for scattering of any bound states, it obeys a crossing symmetry equation which depends on M and N.
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.
The S-matrix of string bound states
Energy Technology Data Exchange (ETDEWEB)
Arutyunov, Gleb [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)], E-mail: g.arutyunov@phys.uu.nl; Frolov, Sergey [School of Mathematics, Trinity College, Dublin 2 (Ireland)], E-mail: frolovs@maths.tcd.ie
2008-11-21
We find the S-matrix which describes the scattering of two-particle bound states of the light-cone string sigma model on AdS{sub 5}xS{sup 5}. We realize the M-particle bound state representation of the centrally extended su(2|2) algebra on the space of homogeneous (super)symmetric polynomials of degree M depending on two bosonic and two fermionic variables. The scattering matrix S{sup MN} of M- and N-particle bound states is a differential operator of degree M+N acting on the product of the corresponding polynomials. We require this operator to obey the invariance condition and the Yang-Baxter equation, and we determine it for the two cases M=1,N=2 and M=N=2. We show that the S-matrices found satisfy generalized physical unitarity, CPT invariance, parity transformation rule and crossing symmetry. Although the dressing factor as a function of four parameters x{sub 1}{sup +},x{sub 1}{sup -},x{sub 2}{sup +},x{sub 2}{sup -} is universal for scattering of any bound states, it obeys a crossing symmetry equation which depends on M and N.
In-medium K̄ interactions and bound states
Directory of Open Access Journals (Sweden)
Gal Avraham
2014-01-01
Full Text Available Correct treatment of subthreshold K̄ N dynamics is mandatory in K− -atom and K̄ -nuclear bound-state calculations, as demonstrated by using in-medium chirally-based models of K̄ N interactions. Recent studies of kaonic atom data reveal appreciable multi-nucleon contributions. K̄ -nuclear widths larger than 50 MeV are anticipated.
Calculation of size for bound-state constituents
Glazek, Stanislaw D
2014-01-01
Elements are given of a calculation that identifies the size of a proton in the Schroedinger equation for lepton-proton bound states, using the renormalization group procedure for effective particles (RGPEP) in quantum field theory, executed only up to the second order of expansion in powers of the coupling constant. Already in this crude approximation, the extraction of size of a proton from bound-state observables is found to depend on the lepton mass, so that the smaller the lepton mass the larger the proton size extracted from the same observable bound-state energy splitting. In comparison of Hydrogen and muon-proton bound-state dynamics, the crude calculation suggests that the difference between extracted proton sizes in these two cases can be a few percent. Such values would match the order of magnitude of currently discussed proton-size differences in leptonic atoms. Calculations using the RGPEP of higher order than second are required for a precise interpretation of the energy splittings in terms of t...
The local characteristics of the bound states of muonic molecules
Energy Technology Data Exchange (ETDEWEB)
Abramov, D.I. [Sankt Peterburgskij Univ., St. Petersburg (Russian Federation); Bogdanova, L.N. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Gusev, V.V. [Institut Fiziki Vysokikh Ehnergij, Protvino (Russian Federation); Ponomarev, L.I. [Rossijskij Nauchnyj Tsentr ``Kurchatovskij Inst.``, Moscow (Russian Federation)
1996-10-01
The sticking probabilities {omega}{sup Jv}, G- and {gamma}-factors for all bound states of mesic molecules HH{mu}, HD{mu}, HT{mu}, DD{mu}, DT{mu}, and TT{mu} with J = 0 and v = 0, 1 have been calculated in the adiabatic hyperspherical approach (AHSA). (orig.). 6 refs.
Nonradiative formation of the positron-helium triplet bound state
di Rienzi, Joseph; Drachman, Richard J.
2007-02-01
We have previously calculated the cross section for radiative formation of the interesting bound state consisting of a positron bound to helium, where the atomic electrons are in the triplet spin state. That process uses the metastable triplet helium system as target, and, as expected, it has a very small cross section. In this paper we examine a more probable process in which the state of interest is produced in an exchange rearrangement collision between a positronium atom and the singlet helium ground state: Ps+He(Se1)→PsHe+(Se3)+e- . The present calculation is done in the plane-wave Born approximation, using simple initial and final wave functions and compares post and prior forms.
Search for exotic baryons in double radiative capture on pionic hydrogen
Zolnierczuk, P A; Christy, E; Clark, J H D; Gorringe, T P; Hasinoff, M D; Kovash, M A; Tripathi, S; Wright, D H
2004-01-01
We report a search for low-lying exotic baryons via double radiative capture on pionic hydrogen. The data were collected at the TRIUMF cyclotron using the RMC spectrometer by detecting gamma-ray pairs from pion stops in liquid hydrogen. No evidence was found to support an earlier claim for exotic baryons of masses 1004 and 1044 MeV/$c^2$. We obtain upper limits on the branching ratios for double radiative capture via these exotic states of $< 3 \\times 10^{-6}$ and $< 4 \\times 10^{-6}$ respectively.
Probing Andreev bound states in one-atom superconducting contacts
Energy Technology Data Exchange (ETDEWEB)
Pothier, Hugues; Janvier, Camille; Tosi, Leandro; Girit, Caglar; Goffman, Marcelo; Esteve, Daniel; Urbina, Cristian [Quantronics Group, SPEC, CEA-Saclay (France)
2015-07-01
Superconductors are characterized by a dissipationless current. Since the work of Josephson 50 years ago, it is known that a supercurrent can even flow through tunnel junctions between superconductors. This Josephson effect also occurs through any type of ''weak links'' between superconductors: non-superconducting materials, constrictions,.. A unified understanding of the Josephson effect has emerged from a mesoscopic description of weak links. It relies on the existence of doublets of localized states that have energies below the superconducting gap: the Andreev bound states. I will present experiments performed on the simplest conductor possible, a single-atom contact between superconductors, that illustrate these concepts. The most recent work demonstrates time-domain manipulation of quantum superpositions of Andreev bound states.
How quantum bound states bounce and the structure it reveals
Lee, Dean
2010-01-01
We investigate how quantum bound states bounce from a hard surface. Our analysis has applications to ab initio calculations of nuclear structure and elastic deformation, energy levels of excitons in semiconductor quantum dots and wells, and cold atomic few-body systems on optical lattices with sharp boundaries. We develop the general theory of elastic reflection for a composite body from a hard wall. On the numerical side we present universal results for two-body states and discuss ab initio calculations for general few-body systems. On the analytical side we derive a universal effective potential that gives the reflection scattering length for shallow two-body states.
Parity lifetime of bound states in a proximitized semiconductor nanowire
Higginbotham, A. P.; Albrecht, S. M.; Kiršanskas, G.; Chang, W.; Kuemmeth, F.; Krogstrup, P.; Jespersen, T. S.; Nygård, J.; Flensberg, K.; Marcus, C. M.
2015-12-01
Quasiparticle excitations can compromise the performance of superconducting devices, causing high-frequency dissipation, decoherence in Josephson qubits, and braiding errors in proposed Majorana-based topological quantum computers. Quasiparticle dynamics have been studied in detail in metallic superconductors but remain relatively unexplored in semiconductor-superconductor structures, which are now being intensely pursued in the context of topological superconductivity. To this end, we use a system comprising a gate-confined semiconductor nanowire with an epitaxially grown superconductor layer, yielding an isolated, proximitized nanowire segment. We identify bound states in the semiconductor by means of bias spectroscopy, determine the characteristic temperatures and magnetic fields for quasiparticle excitations, and extract a parity lifetime (poisoning time) of the bound state in the semiconductor exceeding 10 ms.
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.
Radial sensitivity of kaonic atoms and strongly bound K¯ states
Barnea, N.; Friedman, E.
2007-02-01
The strength of the low-energy K--nucleus real potential has recently received renewed attention in view of experimental evidence for the possible existence of strongly bound K- states. Previous fits to kaonic atom data led to either “shallow” or “deep” potentials, where only the former are in agreement with chiral approaches but only the latter can produce strongly bound states. Here we explore the uncertainties of the K--nucleus optical potentials, obtained from fits to kaonic atom data, using the functional derivatives of the best-fit χ2 values with respect to the potential. We find that only the deep type of potential provides information that is applicable to the K- interaction in the nuclear interior.
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.
R-matrix calculations for few-quark bound states
Energy Technology Data Exchange (ETDEWEB)
Shalchi, M.A. [Instituto de Fisica Teorica, UNESP, Sao Paulo, SP (Brazil); Hadizadeh, M.R. [Ohio University, Institute of Nuclear and Particle Physics and Department of Physics and Astronomy, Athens, OH (United States); Central State University, College of Science and Engineering, Wilberforce, OH (United States)
2016-10-15
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 other methods in momentum and configuration spaces and also by available experimental data. (orig.)
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.
R-matrix calculations for few-quark bound states
Shalchi, M. A.; Hadizadeh, M. R.
2016-10-01
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 other methods in momentum and configuration spaces and also by available experimental data.
SWKB Quantization Rules for Bound States in Quantum Wells
Sinha, A K; Sinha, Anjana; Roychoudhury, Rajkumar
2000-01-01
In a recent paper by Gomes and Adhikari (J.Phys B30 5987(1997)) a matrix formulation of the Bohr-Sommerfield quantization rule has been applied to the study of bound states in one dimension quantum wells. Here we study these potentials in the frame work of supersymmetric WKB (SWKB) quantization approximation and find that SWKB quantization rule is superior to the modified Bohr-Sommerfield or WKB rules as it exactly reproduces the eigenenergies.
Hyperons in the bound state approach with vector mesons
Schat, C L
1994-01-01
We investigate a model for hyperons based on the bound state approach in which vector mesons are explicitly incorporated. We show that for empirical values of the mesonic parameters the strange hyperon spectrum is well reproduced. We also discuss the extension of the model to heavier flavors. We show that the explicit presence of the heavy vectors leads to good predictions for the heavy baryon masses.
Lambda(1405) in the bound state soliton model
Schat, C L; Gobbi, C; Schat, C L; Scoccola, N N; Gobbi, C
1994-01-01
The strong and electromagnetic properties of the Lambda(1405) hyperon are studied in the framework of the bound state soliton model. We explicitly evaluate the strong coupling constant g(Lambda^*-N-K), the Lambda^* magnetic moment, mean square radii and radiative decay amplitudes. The results are shown to be in general agreement with available empirical data. A comparison with results of other models is also presented.
Rapid thermal co-annihilation through bound states in QCD
Kim, Seyong; Laine, M.
2016-07-01
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. The additional enhancement is suggested to originate from bound state formation and subsequent decay. Making use of a Green's function based method to incorporate thermal corrections in perturbative co-annihilation rate computations, we show that qualitative agreement with lattice data can be found once thermally broadened bound states are accounted for. We suggest that our formalism may also be applicable to specific dark matter models which have complicated bound state structures.
Matrix algorithms for solving (in)homogeneous bound state equations.
Blank, M; Krassnigg, A
2011-07-01
In the functional approach to quantum chromodynamics, the properties of hadronic bound states are accessible via covariant integral equations, e.g. the Bethe-Salpeter equation for mesons. In particular, one has to deal with linear, homogeneous integral equations which, in sophisticated model setups, use numerical representations of the solutions of other integral equations as part of their input. Analogously, inhomogeneous equations can be constructed to obtain off-shell information in addition to bound-state masses and other properties obtained from the covariant analogue to a wave function of the bound state. These can be solved very efficiently using well-known matrix algorithms for eigenvalues (in the homogeneous case) and the solution of linear systems (in the inhomogeneous case). We demonstrate this by solving the homogeneous and inhomogeneous Bethe-Salpeter equations and find, e.g. that for the calculation of the mass spectrum it is as efficient or even advantageous to use the inhomogeneous equation as compared to the homogeneous. This is valuable insight, in particular for the study of baryons in a three-quark setup and more involved systems.
Search for a bound state of kaon and pion
Kishimoto, T; Hayakawa, T; Ajimura, S; Itabashi, T; Matsuoka, K; Minami, S; Mitoma, Y; Sakaguchi, A; Shimizu, Y; Terai, K; Sato, T; Noumi, H; Sekimoto, M; Takahashi, H; Fukuda, T; Imoto, W; Mizoi, Y
2012-01-01
We have searched for a bound state of kaon and pion denoted by $X$. The $X$ was conjectured to explain the so-called $\\Theta^+$ resonance as a bound state of kaon, pion and nucleon. This model explains almost all properties of the $\\Theta^+$, however, the model works only if the $K \\pi$ interaction is strongly attractive. It is so strong that it could make a bound state $X$. Here we report a result of the search for the $X$ by using the $K^+ + N \\rightarrow X^+ + N$ reaction at P$_K\\sim$ 1.2 GeV/c. The $X^+ \\rightarrow K^+ \\gamma \\gamma$ decay produces $K^+$ in momentum region where other processes cannot fill. We observed signature of the $X^+$ with statistical significance of 2 $\\sigma$. Production cross section of $X$ with respect to that of $\\pi^0$ is 1$\\pm$0.5% if we take it as an evidence and 1.5% if we set an upper limit.
Effects of QCD bound states on dark matter relic abundance
Liew, Seng Pei
2016-01-01
We study scenarios where there exists an exotic massive particle charged under QCD in the early Universe. We calculate the formation and dissociation rates of bound states formed by pairs of these particles, and apply the results in dark matter (DM) coannihilation scenarios, including also the Sommerfeld effect. We find that on top of the Sommerfeld enhancement, bound-state effects can further significantly increase the largest possible DM masses which can give the observed DM relic abundance, by $\\sim 30 - 100\\%$ with respect to values obtained by considering the Sommerfeld effect only, for the color triplet or octet exotic particles we consider. In particular, it indicates that the Bino DM mass in the right-handed stop-Bino coannihilation scenario in the Minimal Supersymmetric extension of the Standard Model (MSSM) can reach $\\sim 2.5$ TeV. We also apply the bound-state effects in the calculations of relic abundance of long-lived or metastable massive colored particles, and discuss the implications on the B...
Bounds for State Degeneracies in 2D Conformal Field Theory
Hellerman, Simeon
2010-01-01
In this note we explore the application of modular invariance in 2-dimensional CFT to derive universal bounds for quantities describing certain state degeneracies, such as the thermodynamic entropy, or the number of marginal operators. We show that the entropy at inverse temperature 2 pi satisfies a universal lower bound, and we enumerate the principal obstacles to deriving upper bounds on entropies or quantum mechanical degeneracies for fully general CFTs. We then restrict our attention to infrared stable CFT with moderately low central charge, in addition to the usual assumptions of modular invariance, unitarity and discrete operator spectrum. For CFT in the range c_left + c_right < 48 with no relevant operators, we are able to prove an upper bound on the thermodynamic entropy at inverse temperature 2 pi. Under the same conditions we also prove that a CFT can have a number of marginal deformations no greater than ((c_left + c_right) / (48 - c_left - c_right)) e^(4 Pi) - 2.
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.
Computational approach for calculating bound states in quantum field theory
Lv, Q. Z.; Norris, S.; Brennan, R.; Stefanovich, E.; Su, Q.; Grobe, R.
2016-09-01
We propose a nonperturbative approach to calculate bound-state energies and wave functions for quantum field theoretical models. It is based on the direct diagonalization of the corresponding quantum field theoretical Hamiltonian in an effectively discretized and truncated Hilbert space. We illustrate this approach for a Yukawa-like interaction between fermions and bosons in one spatial dimension and show where it agrees with the traditional method based on the potential picture and where it deviates due to recoil and radiative corrections. This method permits us also to obtain some insight into the spatial characteristics of the distribution of the fermions in the ground state, such as the bremsstrahlung-induced widening.
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...
K- and p¯ deeply bound atomic states
Friedman, E.; Gal, A.
1999-12-01
The strongly absorptive optical potentials Vopt which have been deduced from the strong-interaction level shifts and widths in X-ray spectra of K- and p¯ atoms produce effective repulsion leading to substantial suppression of the atomic wave functions within the nucleus. The width of atomic levels then saturates as function of the strength of Im Vopt. We find that `deeply bound' atomic states, which are inaccessible in the atomic cascade process, are generally narrow, due to this mechanism, over the entire periodic table and should be reasonably well resolved. These predictions are insensitive to Vopt, provided it was fitted to the observed X-ray spectra. In contrast, the nuclear states bound by Vopt are very broad and their spectrum depends sensitively on details of Vopt. We discuss production reactions for K- atomic states using slow K- mesons from the decay of the φ(1020) vector meson, and the ( p¯,p ) reaction for p¯ atomic states. Rough cross section estimates are given.
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.
Exotic Hadron Bound State Production at Hadronic Colliders
Jin, Yi; Liu, Yan-Rui; Meng, Lu; Si, Zon-Guo; Zhang, Xiao-Feng
2016-01-01
The non-relativistic wave function framework is applied to study the production and decay of the exotic hadrons which can be effectively described as bound states of other hadrons. The ingredient hadron production can be calculated by event generators. We investigate the production of exotic hadrons in the multiproduction processes at high energy hadronic colliders with the help of the event generators. We illustrate the crucial information such as their momentum distributions and production rate for the measurements at the large hadron collider. This study provides crucial information for the measurements of the relevant exotic hadrons.
Scattering and Bound States of a Deformed Quantum Mechanics
Ching, Chee-Leong
2012-01-01
We construct the exact position representation of a deformed quantum mechanics which exhibits an intrinsic maximum momentum and use it to study problems such as a particle in a box and scattering from a step potential, among others. In particular, we show that unlike usual quantum mechanics, the present deformed case delays the formation of bound states in a finite potential well. In the process we also highlight some limitations and pit-falls of low-momentum or perturbative treatments and thus resolve two puzzles occurring in the literature.
Diquark bound states at far beyond ladder truncation
Jinno, Ryusuke; Mishima, Go
2015-01-01
The Bethe-Salpeter equation in the diquark channel is investigated by employing the Dyson-Schwinger method together with the Munczek-Nemirovsky model. The novelty of our study is a resummation of completely-crossed ladder diagrams in the Bethe-Salpeter kernel. These diagrams are enhanced due to their color factors in the diquark channel, but not in the meson channel. As a result of our analysis, it is suggested that diquark bound-state solutions exist in the Bethe-Salpeter equation, which have been thought to be absent.
Are $\\eta$- and $\\omega$-nuclear states bound ?
Tsushima, K; Thomas, A W; Saitô, K
1998-01-01
We investigate theoretically whether it is feasible to detect $\\eta$- and $^{40}$Ca, $^{90}$Zr and $^{208}$Pb, we also investigate $^6$He, $^{11}$B and $^{26}$Mg, which are the final nuclei in the proposed experiment involving the (d,$^3$He) reaction at GSI. Potentials for the $\\eta$ and $\\omega$ mesons in these nuclei are calculated in local density approximation, embedding the mesons in the nucleus described by solving the mean-field equations of motion in the QMC model. Our results suggest that one should expect to find $\\eta$- and $\\omega$-nucleus bound states in all these nuclei.
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.
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.
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.
Petridou, Chariclia I.
We studied the pp annihilations at rest looking for narrow bound states in the proton-antiproton system. We looked, with high energy resolution, for radiative and pionic transitions in the gamma and charged pion spectra. The detector for the (gamma)(--->)e+e- and the (pi)('(+OR-)) was a magnetic pair spectrometer. The directions of the incident particles (e(+OR-) and (pi)(+OR-)) were determined by a drift chamber module in front of the magnet and the final directions of the particles, if reflected in the magnet, by the same chamber; if transversing the magnet, by an identical module at the rear of the magnet. The momentum was calculated from the directions of the particle. The following gamma spectra were obtained. Gammas with both e+, e- reflected in the magnet at a field of about 6 Kgauss (RR-gammas). That covers the region between 80 and 180 MeV, corresponding to a missing mass 1794 to 1686 MeV/c. The energy resolution is about 2.5 MeV ((sigma)) at 129 MeV (confirmed by the observed Panofsky gammas from stopping (pi)('-)p data) and 5 MeV ((sigma)) at 80 MeV. We have no evidence for narrow peaks except for the Panofsky gamma produced with a branching ratio of 3.3 x 10('-3) from (pi)('-) stops in the target. Upper limits for (gamma) -transitions in the region between 80 to 180 MeV were set at about 10('-3). Gammas with one e+(e-) reflected and the other transversing the magnet (RP-gammas) for fields of about 6 and 12 Kgauss, covering the region (GREATERTHEQ) 200 MeV, which corresponds to missing mass (LESSTHEQ) 1664 MeV/c('2). The gamma energy resolution in MeV is 51(.)E('2) (GeV) and 25.5(.)E('2)(GeV) for the low and high field respectively. Finally the charged pion spectra for those transversing the magnet are given for both magnet settings and as a function of charge multiplicity, covering the momentum region from (GREATERTHEQ) 150 MeV/c. The momentum resolution is the same as that for the RP-gammas. The two body annihilations (pi)('+)(pi)('-) and (pi
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...
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.
Three-nucleon bound states using realistic potential models
Nogga, A.; Kievsky, A.; Kamada, H.; Glöckle, W.; Marcucci, L. E.; Rosati, S.; Viviani, M.
2003-03-01
The bound states of 3H and 3He have been calculated by using the Argonne v18 plus the Urbana IX three-nucleon potential. The isospin T=3/2 state have been included in the calculations as well as the n-p mass difference. The 3H-3He mass difference has been evaluated through the charge-dependent terms explicitly included in the two-body potential. The calculations have been performed using two different methods: the solution of the Faddeev equations in momentum space and the expansion on the correlated hyperspherical harmonic basis. The results are in agreement within 0.1% and can be used as benchmark tests. Results for the charge-dependent Bonn interaction in conjunction with the Tucson-Melbourne three-nucleon force are also presented. It is shown that the 3H and 3He binding energy difference can be predicted model independently.
The three-nucleon bound state using realistic potential models
Nogga, A; Kamada, H; Glöckle, W; Marcucci, L E; Rosati, S; Viviani, M
2003-01-01
The bound states of $^3$H and $^3$He have been calculated using the Argonne $v_{18}$ plus the Urbana three-nucleon potential. The isospin $T=3/2$ state have been included in the calculations as well as the $n$-$p$ mass difference. The $^3$H-$^3$He mass difference has been evaluated through the charge dependent terms explicitly included in the two-body potential. The calculations have been performed using two different methods: the solution of the Faddeev equations in momentum space and the expansion on the correlated hyperspherical harmonic basis. The results are in agreement within 0.1% and can be used as benchmark tests. Results for the CD-Bonn interaction are also presented. It is shown that the $^3$H and $^3$He binding energy difference can be predicted model independently.
Lower Bound for entanglement cost of antisymmetric states
Shimono, T
2002-01-01
This report gives a lower bound of entanglement cost for antisymmetric states of bipartite d-level systems to be log_2 (d/(d-1)) ebit (for d=3, E_c >= 0.585...). The paper quant-ph/0112131 claims that the value is equal to one ebit for d=3, since all of the eigenvalues of reduced matrix of any pure states living in N times tensor product of antisymmetric space is not greater than 2^(-N) thus the von Neumann entropy is not less than N, but the proof is not true. Hence whether the value is equal to or less than one ebit is not clear at this moment.
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)
Quantum state discrimination bounds for finite sample size
Audenaert, Koenraad M R; Verstraete, Frank
2012-01-01
In the problem of quantum state discrimination, one has to determine by measurements the state of a quantum system, based on the a priori side information that the true state is one of two given and completely known states, rho or sigma. In general, it is not possible to decide the identity of the true state with certainty, and the optimal measurement strategy depends on whether the two possible errors (mistaking rho for sigma, or the other way around) are treated as of equal importance or not. Recent results on the quantum Chernoff and Hoeffding bounds show that, if several copies of the system are available then the optimal error probabilities decay exponentially in the number of copies, and the decay rate is given by a certain statistical distance between rho and sigma (the Chernoff distance and the Hoeffding distances, respectively). While these results provide a complete solution for the asymptotic problem, they are not completely satisfying from a practical point of view. Indeed, in realistic scenarios ...
Lasing action from photonic bound states in continuum
Kodigala, Ashok; Lepetit, Thomas; Gu, Qing; Bahari, Babak; Fainman, Yeshaiahu; Kanté, Boubacar
2017-01-01
In 1929, only three years after the advent of quantum mechanics, von Neumann and Wigner showed that Schrödinger’s equation can have bound states above the continuum threshold. These peculiar states, called bound states in the continuum (BICs), manifest themselves as resonances that do not decay. For several decades afterwards the idea lay dormant, regarded primarily as a mathematical curiosity. In 1977, Herrick and Stillinger revived interest in BICs when they suggested that BICs could be observed in semiconductor superlattices. BICs arise naturally from Feshbach’s quantum mechanical theory of resonances, as explained by Friedrich and Wintgen, and are thus more physical than initially realized. Recently, it was realized that BICs are intrinsically a wave phenomenon and are thus not restricted to the realm of quantum mechanics. They have since been shown to occur in many different fields of wave physics including acoustics, microwaves and nanophotonics. However, experimental observations of BICs have been limited to passive systems and the realization of BIC lasers has remained elusive. Here we report, at room temperature, lasing action from an optically pumped BIC cavity. Our results show that the lasing wavelength of the fabricated BIC cavities, each made of an array of cylindrical nanoresonators suspended in air, scales with the radii of the nanoresonators according to the theoretical prediction for the BIC mode. Moreover, lasing action from the designed BIC cavity persists even after scaling down the array to as few as 8-by-8 nanoresonators. BIC lasers open up new avenues in the study of light-matter interaction because they are intrinsically connected to topological charges and represent natural vector beam sources (that is, there are several possible beam shapes), which are highly sought after in the fields of optical trapping, biological sensing and quantum information.
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.
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.
Three-boson bound states in finite volume with EFT
Kreuzer, S.; Hammer, H.-W.
2010-04-01
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 for systems with positive and negative two-body scattering length. We compare the full results to results obtained using an expansion around the infinite volume binding energy. The renormalization of the Effective Field Theory in the finite volume is verified explicitly.
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.
Weakly bound states with spin-isospin symmetry
Kievsky, A.; Gattobigio, M.
2016-03-01
We discuss weakly bound states of a few-fermion system having spin-isospin symmetry. This corresponds to the nuclear physics case in which the singlet, a0, and triplet, a1, n - p scattering lengths are large with respect to the range of the nuclear interaction. The ratio of the two is about a0/a1 ≈ -4.31. This value defines a plane in which a0 and a1 can be varied up to the unitary limit, 1/a0 = 0 and 1/a1 = 0, maintaining its ratio fixed. Using a spin dependant potential model we estimate the three-nucleon binding energy along that plane. This analysis can be considered an extension of the Efimov plot for three bosons to the case of three 1/2-spin-isospin fermions.
Weakly bound states with spin-isospin symmetry
Kievsky, A
2015-01-01
We discuss weakly bound states of a few-fermion system having spin-isospin symmetry. This corresponds to the nuclear physics case in which the singlet, $a_0$, and triplet, $a_1$, $n-p$ scattering lengths are large with respect to the range of the nuclear interaction. The ratio of the two is about $a_0/a_1\\approx-4.31$. This value defines a plane in which $a_0$ and $a_1$ can be varied up to the unitary limit, $1/a_0=0$ and $1/a_1=0$, maintaining its ratio fixed. Using a spin dependant potential model we estimate the three-nucleon binding energy along that plane. This analysis can be considered an extension of the Efimov plot for three bosons to the case of three $1/2$-spin-isospin fermions.
Weakly bound states with spin-isospin symmetry
Directory of Open Access Journals (Sweden)
Kievsky A.
2016-01-01
Full Text Available We discuss weakly bound states of a few-fermion system having spin-isospin symmetry. This corresponds to the nuclear physics case in which the singlet, a0, and triplet, a1, n − p scattering lengths are large with respect to the range of the nuclear interaction. The ratio of the two is about a0/a1 ≈ −4.31. This value defines a plane in which a0 and a1 can be varied up to the unitary limit, 1/a0 = 0 and 1/a1 = 0, maintaining its ratio fixed. Using a spin dependant potential model we estimate the three-nucleon binding energy along that plane. This analysis can be considered an extension of the Efimov plot for three bosons to the case of three 1/2-spin-isospin fermions.
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...
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.
Bounds for entanglement of formation of two mode squeezed thermal states
Chen, X Y; Chen, Xiao-Yu; Qiu, Pei-liang
2003-01-01
The upper and lower bounds of entanglement of formation are given for two mode squeezed thermal state. The bounds are compared with other entanglement measure or bounds. The entanglement distillation and the relative entropy of entanglement of infinitive squeezed state are obtained at the postulation of hashing inequality.
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.
Bound state spectra of the 3D rational potential
Roy, Amlan K; Proynov, Emil I
2010-01-01
We present bound state spectra of the 3D rational potential, $V(r)=r^2 + \\lambda r^2/(1+gr^2)$, $g>0$, by means of the generalized pseudospectral method. All the thirty states corresponding to $n$=0--9 are considered for the first time for a broad range of coupling parameters. These results surpass the accuracy of \\emph{all} other existing calculations published so far except the finite-difference method, which yields similar accuracy as ours. Variation of energies and radial distribution functions is followed with respect to the interaction parameters. Special emphasis has been laid on \\emph{higher} excitations and \\emph{negative} values of the interaction, where relatively less work has been reported. The energy sequence is found to be different for positive and negative interaction; numerically following a mirror-image relationship \\emph{usually}, if not always. Additionally, twenty energy splittings arising from certain levels belonging to $n$=0--9 are systematically studied as functions of the potential ...
ABC Effect in Double-Pionic Fusion - a New Resonance?
Pricking, A.; Bashkanov, M.; Clement, H.; Doroshkevich, E.; Perez del Rio, E.; Skorodko, T.; Wagner, G. J.
2012-12-01
ABC effect, an intriguing low-mass enhancement in the ππ invariant mass spectrum — known since more than 50 years from inclusive measurements of double-pionic fusion reactions — is reexamined. To this end exclusive and kinematically complete high-statistics experiments of the fusion reactions to d, 3He and 4He have been carried out with WASA at COSY. These measurements cover the full energy region, where the ABC effect has been observed previously. They also complement the systematic measurements of nucleon-nucleon induced two-pion production. An isospin decomposition of all three basic double-pionic fusion reactions leading to the deuteron uniquely shows that solely the isoscalar reaction part exhibits the ABC effect tightly correlated with a narrow resonance structure in the total cross section. The peak energy of the resonance structure is about 90 MeV below the nominal ΔΔ threshold of 2 mΔ and its width of only 70 MeV is much less than the 2 ГΔ expected from the conventional t-channel ΔΔ process. Based on angular distributions the quantum numbers I(JP) = 0(3+) have been assigned. In the double-pionic fusion reaction dd→4Heπ0π0 again the ABC effect is observed to be correlated with the appearance of a resonance-like structure in the total cross section at the same excess energy. From this we conclude that this resonance structure obviously is strong enough to survive even in nuclei.
Observation of double radiative capture on pionic hydrogen
Tripathi, S; Christy, M E; Clark, J H D; Gorringe, T P; Hasinoff, M D; Kovash, M A; Wright, D H; Zolnierczuk, P A
2002-01-01
We report the first observation of double radiative capture on pionic hydrogen. The experiment was conducted at the TRIUMF cyclotron using the RMC spectrometer, and detected $\\gamma$--ray coincidences following $\\pi^-$ stops in liquid hydrogen. We found the branching ratio for double radiative capture to be $(3.08 \\pm 0.44) \\times 10^{-5}$. The measured branching ratio and angle-energy distributions support the theoretical prediction of a dominant contribution from the $\\pi \\pi \\to \\gamma \\gamma$ annihilation mechanism.
Indications of partial chiral symmetry restoration from pionic atoms
Friedman, E.
2002-01-01
Extensive data on strong interaction effects in pionic atoms are analyzed with a density-dependent isovector scattering amplitude suggested recently by Weise to result from a density dependence of the pion decay constant. Most of the so-called 'missing s-wave repulsion' is removed when adopting this approach, thus indicating a partial chiral symmetry restoration in dense matter. The resulting potentials describe quite well also elastic scattering of 20 MeV pions on Ca. Further tests with elastic scattering are desirable.
Baryons as relativistic three-quark bound states
Eichmann, Gernot; Sanchis-Alepuz, Hèlios; Williams, Richard; Alkofer, Reinhard; Fischer, Christian S.
2016-11-01
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 processes and Compton scattering determined in the Dyson-Schwinger framework with those of lattice QCD and the available experimental data. The general aim is to identify the underlying physical mechanisms behind the plethora of observable phenomena in terms of the underlying quark and gluon degrees of freedom.
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.
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
Neutron skins of 208Pb and 48Ca from pionic probes
Friedman, E.
2012-12-01
The neutron skin of 208Pb has received considerable attention in recent years. A variety of strongly-interacting probes depict a rather consistent picture but pionic probes have not been referred to in this context. We present here neutron-skin values from pionic atoms and from total reaction cross sections of π+ between 0.7 and 2 GeV/c which fit well into the picture. In addition we show that a neutron-skin for 48Ca can be obtained from existing data on pionic atoms and the result agrees with pion scattering experiments and with the scattering of α particles.
String Models for the Heavy Quark-Antiquark Bound States.
Tse, Sze-Man
1988-12-01
The heavy quark-antiquark bound state is examined in the phenomenological string models. Specifically, the Nambu-Goto model and the Polyakov's smooth string model are studied in the large-D limit, D being the number of transverse space-time dimensions. The static potential V(R) is extracted in both models in the large-D limit. In the former case, this amounts to the usual saddle point calculation. In the latter case, the renormalized, physical string tension is expressed in terms of the bare string tension and the extrinsic curvature coupling. A systematic loop expansion of V(R) is developed and carried out explicitly to one loop order, with the two loops result presented without detail. For large separations R, the potential is linear in R with corrections of order 1/R. The coefficient of the 1/R Luscher term has the universal value -piD/24 to any finite order in the loop expansion. For very small separations R, the potential V(R) is also proportional to 1/R with a coefficient twice that of Luscher's term. The corrections are logarithmically small. Polyakov's smooth string model is extended to the finite temperature situation. The temperature dependence of the string tension is investigated in the large-D limit. The effective string tension is calculated to the second order in the loop expansion. At low temperature, it differs from that of the Nambu-Goto model only by terms that fall exponentially with inverse temperature. Comparison of the potential V(R) in the smooth string model with lattice gauge calculation and hadron spectroscopy data yields a consistent result.
Trilinear couplings and scalar bound states in supersymmetric extensions of the standard model
Hernández, Pilar; Sanz, V
2001-01-01
The trilinear terms in minimal supersymmetric extensions of the standard model can be responsible of forming a bound state of scalars. In this talk we outline our results on the study of this bound state using a non-perturbative method, the exact renormalization group. We focus on the trilinear term between the Higgs and stop fields. (4 refs).
The Bethe ansatz for AdS5 × S5 bound states
de Leeuw, M.
2009-01-01
We reformulate the nested coordinate Bethe ansatz in terms of coproducts of Yangian symmetry generators. This allows us to derive the nested Bethe equations for arbitrary bound state string S-matrices. The bound state number dependence in the Bethe equations appears through the parameters x± and the
Bound states for fermions in the gauge Aharonov-Bohm field
Energy Technology Data Exchange (ETDEWEB)
Voropaev, S.A.; Galtsov, D.V.; Spasov, D.A. (Dept. of Theoretical Physics, Moscow State Univ. (USSR))
1991-09-05
In this paper we discuss some interesting properties of the Aharonov-Bohm interaction for relativistic spin-one-half particles. We will show that the AB potential is powerful enough to create bound states. We will then discuss the wave function, spin-coefficients and the energy level for the bound states of the fermions in the gauge AB field. (orig.).
The bound state S-matrix for AdS5×S5 superstring
Arutyunov, G.E.; de Leeuw, M.; Torrielli, A.
2009-01-01
We determine the S-matrix that describes scattering of arbitrary bound states in the light-cone string theory in AdS5×S5. The corresponding construction relies on the Yangian symmetry and the superspace formalism for the bound state representations. The basic analytic structure supporting the S-matr
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, ...
Ndangali, Friends R
2010-01-01
Electromagnetic bound states in the radiation continuum are studied for periodic double arrays of subwavelength dielectric cylinders in TM polarization. They are similar to localized waveguide mode solutions of Maxwell's equations for metal cavities or defects of photonic crystals, but, in contrast to the latter, their spectrum lies in the radiation continuum. The phenomenon is identical to the existence of bound sates in the radiation continuum in quantum mechanics, discovered by von Neumann and Wigner. In the formal scattering theory, these states appear as resonances with the vanishing width. For the system studied, the bound states are shown to exist at specific distances between the arrays in the spectral region where one or two diffraction channels are open. Analytic solutions are obtained for all bound states (below the radiation continuum and in it) in the limit of thin cylinders (the cylinder radius is much smaller than the wavelength). The existence of bound states is also established in the spectra...
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.
Formation of bound states in expanded metal studied via path integral molecular dynamics
Deymier, P. A.; Oh, Ki-Dong
2004-03-01
The usefulness of the restricted path integral molecular dynamics method for the study of strongly correlated electrons is demonstrated by studying the formation of bound electronic states in a half-filled expanded three-dimensional hydrogenoid body-centred cubic lattice at finite temperature. Starting from a metallic state with one-component plasma character, we find that bound electrons form upon expansion of the lattice. The bound electrons are spatially localized with their centre for the motion of gyration located at ionic positions. The number of bound electrons increases monotonically with decreasing density.
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.
Bound states of Dipolar Bosons in One-dimensional Systems
DEFF Research Database (Denmark)
G. Volosniev, A.; R. Armstrong, J.; V. Fedorov, D.;
2013-01-01
-body structures in this geometry are determined as function of polarization angles and dipole strength by using both essentially exact stochastic variational methods and the harmonic approximation. The main focus is on the three, four, and five-body problems in two or more tubes. Our results indicate...... that in the weakly-coupled limit the inter-tube interaction is similar to a zero-range term with a suitable rescaled strength. This allows us to address the corresponding many-body physics of the system by constructing a model where bound chains with one molecule in each tube are the effective degrees of freedom...
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.
Becis-Aubry, Yasmina; Boutayeb, Mohamed; Darouach, Mohamed
2006-01-01
International audience; This contribution proposes a recursive and easily implementable online algorithm for state estimation of multi-output discrete-time systems with nonlinear dynamics and linear measurements in presence of unknown but bounded disturbances corrupting both the state and measurement equations. The proposed algorithm is based on state bounding techniques and is decomposed into two steps : time update and observation update that uses a switching estimation Kalman-like gain mat...
Binding Energy of Quantum Bound States in X-shaped Nanowire Intersection
2014-01-01
that with non-zero magnetic field new structures are associated with virtual and resonant states located at the junction that becomes 2D Landau ...results of our model system (cross-wire intersecting at an arbitrary angle) not only supplement the theory of quantum bound state in a classically unbound...geometries has been a long standing problem in quantum theory . Knowledge of quantum bound states in crossed nanowire system is very important in
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.
High-precision measurement of strong-interaction effects in pionic deuterium
Energy Technology Data Exchange (ETDEWEB)
Strauch, Thomas
2009-06-30
The hadronic ground state shift {epsilon}{sub 1s} and width {gamma}{sub 1s} in pionic deuterium were measured with high precision at the pion factory of the Paul Scherrer Institut (PSI), Switzerland (PSI-Experiment R-06.03). In this experiment the {pi}D(3p-1s) X-ray transition of about 3 keV was measured using a high-resolution Bragg crystal spectrometer equipped with a large-area position sensitive CCD detector. The characteristic X-radiation stems from a de-excitation cascade of the pionic atom. In order to produce an intense X-ray source, the cyclotron trap was used to stop pions in a cryogenic D{sub 2} target after winding up the pion beam in a magnetic field. The hadronic shift {epsilon}{sub 1s} is obtained from the measured transition energy by comparison to the pure electromagnetic value, where the determination of the broadening {gamma}{sub 1s} requires the precise knowledge of the spectrometer response, obtained from measurements of narrow X-ray transitions from highly ionised atoms, produced in an electron cyclotron resonance ion trap. As the formation rate is assumed to be density dependent, the {pi}D(3p-1s) X-ray energy was measured at three different D{sub 2} pressures. Another cascade process (Coulomb de-excitation) transforms the energy release of de-excitation steps into kinetic energy of the collision partners leading to a Doppler broadening of subsequent X-ray transitions. The hadronic broadening {gamma}{sub 1s} is only obtained after deconvolution of the spectrometer response function and the contributions from Doppler broadening. No energy dependence of the {pi}D(3p-1s) was found, and it is concluded that radiative de-excitation from molecular states is negligible within the experimental accuracy. Hence, the result for the shift reads {epsilon}{sub 1s} = (-2.325{+-}0.031) eV, corresponding to an accuracy of 1.3% and represents the average of the three measured densities. The uncertainty is dominated by the accuracy of the gallium K{alpha}{sub 2
Taming the Yukawa potential singularity: improved evaluation of bound states and resonance energies
Alhaidari, A D; Abdelmonem, M S
2007-01-01
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 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 demonstrate the remarkable fact that bound states cross over into resonance states by varying the potential parameters.
Bicudo, P.; Cardoso, M.
2016-11-01
We address q q Q ¯Q ¯ exotic tetraquark bound states and resonances with a fully unitarized and microscopic quark model. We propose a triple string flip-flop potential, inspired by lattice QCD tetraquark static potentials and flux tubes, combining meson-meson and double Y potentials. Our model includes the color excited potential, but neglects the spin-tensor potentials, as well as all the other relativistic effects. To search for bound states and resonances, we first solve the two-body mesonic problem. Then we develop fully unitary techniques to address the four-body tetraquark problem. We fold the four-body Schrödinger equation with the mesonic wave functions, transforming it into a two-body meson-meson problem with nonlocal potentials. We find bound states for some quark masses, including the one reported in lattice QCD. Moreover, we also find resonances and calculate their masses and widths, by computing the T matrix and finding its pole positions in the complex energy plane, for some quantum numbers. However, a detailed analysis of the quantum numbers where binding exists shows a discrepancy with recent lattice QCD results for the l l b ¯ b ¯ tetraquark bound states. We conclude that the string flip-flop models need further improvement.
Cruising through molecular bound-state manifolds with radiofrequency
Lang, F.; van der Straten, P.; Brandstätter, B.; Thalhammer, G.; Winkler, K.; Julienne, P.S.; Grimm, R.; Hecker Denschlag, J.
2008-01-01
The production of ultracold molecules with their rich internal structure is currently attracting considerable interest1, 2, 3, 4. For future experiments, it will be important to efficiently transfer these molecules from their initial internal quantum state at production to other quantum states of in
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....
Quark-antiquark bound-state spectroscopy and QCD
Energy Technology Data Exchange (ETDEWEB)
Bloom, E.D.
1982-11-01
The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in experiment, the charmonium model, the mass of states, fine structure and hyperfine structure, classification, widths of states, rate and multipolarity of gamma transitions, questions about bottom, leptonic widths and the determination of Q/sub b/, the mass splitting of the n/sup 3/S/sub 1/ states, the center of gravity of the masses of the n/sup 3/P; states, n/sup 3/ P; fine structure and classification, branching ratios for upsilon' ..-->.. tau chi/sub 6j/ and the tau cascade reactions, hyperfine splitting, and top. (GHT)
Dvornikov, Maxim
2011-01-01
I reply here to the comment of Dr Shmatov on my recent work and demonstrate the invalidity of his criticism of the classical physics description of the formation of bound states of electrons participating in spherically symmetric oscillations of plasma.
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 ...
Impurity bound states in fully gapped d-wave superconductors with subdominant order parameters
Mashkoori, Mahdi; Björnson, Kristofer; Black-Schaffer, Annica M.
2017-01-01
Impurities in superconductors and their induced bound states are important both for engineering novel states such as Majorana zero-energy modes and for probing bulk properties of the superconducting state. The high-temperature cuprates offer a clear advantage in a much larger superconducting order parameter, but the nodal energy spectrum of a pure d-wave superconductor only allows virtual bound states. Fully gapped d-wave superconducting states have, however, been proposed in several cuprate systems thanks to subdominant order parameters producing d + is- or d + id′-wave superconducting states. Here we study both magnetic and potential impurities in these fully gapped d-wave superconductors. Using analytical T-matrix and complementary numerical tight-binding lattice calculations, we show that magnetic and potential impurities behave fundamentally different in d + is- and d + id′-wave superconductors. In a d + is-wave superconductor, there are no bound states for potential impurities, while a magnetic impurity produces one pair of bound states, with a zero-energy level crossing at a finite scattering strength. On the other hand, a d + id′-wave symmetry always gives rise to two pairs of bound states and only produce a reachable zero-energy level crossing if the normal state has a strong particle-hole asymmetry. PMID:28281570
Impurity bound states in fully gapped d-wave superconductors with subdominant order parameters.
Mashkoori, Mahdi; Björnson, Kristofer; Black-Schaffer, Annica M
2017-03-10
Impurities in superconductors and their induced bound states are important both for engineering novel states such as Majorana zero-energy modes and for probing bulk properties of the superconducting state. The high-temperature cuprates offer a clear advantage in a much larger superconducting order parameter, but the nodal energy spectrum of a pure d-wave superconductor only allows virtual bound states. Fully gapped d-wave superconducting states have, however, been proposed in several cuprate systems thanks to subdominant order parameters producing d + is- or d + id'-wave superconducting states. Here we study both magnetic and potential impurities in these fully gapped d-wave superconductors. Using analytical T-matrix and complementary numerical tight-binding lattice calculations, we show that magnetic and potential impurities behave fundamentally different in d + is- and d + id'-wave superconductors. In a d + is-wave superconductor, there are no bound states for potential impurities, while a magnetic impurity produces one pair of bound states, with a zero-energy level crossing at a finite scattering strength. On the other hand, a d + id'-wave symmetry always gives rise to two pairs of bound states and only produce a reachable zero-energy level crossing if the normal state has a strong particle-hole asymmetry.
Raman scattering from a superconductivity-induced bound state in MgB2.
Zeyher, R
2003-03-14
It is shown that the sharp peak in the E(2g) Raman spectrum of superconducting MgB2 is due to a bound state caused by the electron-phonon coupling. Our theory explains why this peak appears only in the spectra with E(2g) symmetry and only in the sigma but not the pi bands. The properties of the bound state and the Raman spectrum are investigated, also in the presence of impurity scattering.
Exact bound state solutions of the Klein-Gordon particle in Hulthén potential
Institute of Scientific and Technical Information of China (English)
Zhang Min-Cang
2008-01-01
In this paper,the Klein-Gordon equation with the spherical symmetric Hulthén potential is turned into a hypergeometric equation and is solved in the framework of function analysis exactly.The corresponding bound state solutions are expressed in terms of the hypergeometric function,and the energy spectrum of the bound states is obtained as a solution to a given equation by boundary constraints.
Institute of Scientific and Technical Information of China (English)
LIU Hui; HOU De-Fu; LI Jia-Rong
2009-01-01
We investigate the in-medium interparticle potential of hot gauge system with bound states by employing the QED and scalar QED coupling. At the finite temperature an oscillatory behavior of the potential has been found as well as its variation in terms of different free parameters. We expect the competition among the parameters will lead to an appropriate interparticle potential, which could be extended to discuss the fluid properties of QGP with scalar bound states.
Eta bound states in nuclei: a probe of flavour-singlet dynamics
Energy Technology Data Exchange (ETDEWEB)
Steven D. Bass; Anthony W. Thomas
2005-07-01
We argue that eta bound states in nuclei are sensitive to the singlet component in the eta. The bigger the singlet component, the more attraction and the greater the binding. Thus, measurements of eta bound states will yield new information about axial U(1) dynamics and glue in mesons. Eta - etaprime mixing plays an important role in understanding the value of the eta-nucleon scattering length.
Calculations of bar K-nuclear quasi-bound states using chiral bar KN amplitudes
Mareš, J.; Barnea, N.; Cieplý, A.; Friedman, E.; Gal, A.; Gazda, D.
2014-03-01
We review our recent calculations of K- quasi-bound states in nuclear systems using subthreshold energy dependent chiral bar KN amplitudes. Strong energy dependence of the scattering amplitudes requires self-consistent evaluation of the involved bar KN interactions. In view of sizable widths predicted by our calculations, an unambiguous identification of K--nuclear quasi-bound states in ongoing experimental searches would be difficult.
Bound Electron States in Skew-symmetric Quantum Wire Intersections
2014-01-01
dots is that they lie far beneath the surface of the surround- ing material whose associated states are potentially meddlesome. Colloidal chemistry ... textbooks have posed problems dealing with these states, but the approaches used in these problems involved variational methods or limiting cases, which are...of the Introductory Quantum Mechanics textbook by D.J.Griffith (Pearson, 2005). My trial function that has been developed in this the- sis, has an
Scaling and universality in two dimensions: three-body bound states with short-ranged interactions
Energy Technology Data Exchange (ETDEWEB)
Bellotti, F F; Frederico, T [Instituto Tecnologico de Aeronautica, DCTA, 12.228-900 Sao Jose dos Campos, SP (Brazil); Yamashita, M T [Instituto de Fisica Teorica, UNESP-Univ Estadual Paulista, CP 70532-2, CEP 01156-970, Sao Paulo, SP (Brazil); Fedorov, D V; Jensen, A S; Zinner, N T, E-mail: zinner@phys.au.dk [Department of Physics and Astronomy-Aarhus University, Ny Munkegade, bygn. 1520, DK-8000 Arhus C (Denmark)
2011-10-28
The momentum space zero-range model is used to investigate universal properties of three interacting particles confined to two dimensions. The pertinent equations are first formulated for a system of two identical and one distinct particle and the two different two-body subsystems are characterized by two-body energies and masses. The three-body energy in units of one of the two-body energies is a universal function of the other two-body energy and the mass ratio. We derive convenient analytical formulae for calculations of the three-body energy as a function of these two independent parameters and exhibit the results as universal curves. In particular, we show that the three-body system can have any number of stable bound states. When the mass ratio of the distinct to identical particles is greater than 0.22, we find that at most two stable bound states exist, while for two heavy and one light mass an increasing number of bound states is possible. The specific number of stable bound states depends on the ratio of two-body bound state energies and on the mass ratio, and we map out an energy-mass phase diagram of the number of stable bound states. Realizable systems of both fermions and bosons are discussed in this framework.
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......-linear yield criteria. The aim of the paper is to refine an earlier presented effective method which reduces the number of optimisation variables considerably by eliminating the equilibrium equations a priori and improvements are made on the interior point optimisation algorithm....
QQqq Four-Quark Bound States in Chiral SU(3) Quark Model
Institute of Scientific and Technical Information of China (English)
ZHANG Ming; ZHANG Hai-Xia; ZHANG Zong-Ye
2008-01-01
The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU(3) quark model, where Q is the heavy quark (c or b) and q is the light quark (u, d, or s). We obtain a bound state for the bbnn configuration with quantum number JP=1+, I=0 and for the ccnn (JP=1+, I=0) configuration, which is not bound but slightly above the D*D* threshold (n is u or d quark). Meanwhile, we also conclude that a weakly bound state in bbnn system can also be found without considering the chiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.
Andreev bound states for cake shape superconducting-normal systems
Energy Technology Data Exchange (ETDEWEB)
Cserti, J; Beri, B; Kormanyos, A; Pollner, P; Kaufmann, Z [Department of Physics of Complex Systems, Eoetvoes University, H-1117 Budapest, Pazmany Peter setany 1/A (Hungary)
2004-09-22
The energy spectrum of cake shape normal-superconducting systems is calculated by solving the Bogoliubov-de Gennes equation. We take into account the mismatch in the effective masses and Fermi energies of the normal and superconducting regions as well as the potential barrier at the interface. In the case of a perfect interface and without mismatch, the energy levels are treated by semi-classics. Analytical expressions for the density of states and its integral, the step function, are derived and compared with that obtained from exact numerics. We find a very good agreement between the two calculations. It is shown that the spectrum possesses an energy gap and the density of states is singular at the edge of the gap. The effect of the mismatch and the potential barrier on the gap is also investigated.
Is the exotic X(5568) a bound state?
Energy Technology Data Exchange (ETDEWEB)
Chen, Xiaoyun; Ping, Jialun [Nanjing Normal University, Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems, Nanjing (China)
2016-06-15
Stimulated by the recent observation of the exotic X(5568) state by the D0 Collaboration, we study the four-quark system us anti b anti d with quantum numbers J{sup P} = 0{sup +} in the framework of the chiral quark model. Two structures, diquark-antidiquark and meson-meson, with all possible color configurations are investigated by using the Gaussian expansion method. The results show that the energies of the tetraquark states with diquark-antiquark structure are too high to be candidates of X(5568), and no molecular structure can be formed in our calculations. The calculation is also extended to the four-quark system us anti c anti d and the same results as that of us anti b anti d are obtained. (orig.)
Bethe-Salpeter bound-state structure in Minkowski space
Gutierrez, C; Frederico, T; Salmè, G; Viviani, M; Tomio, Lauro
2016-01-01
The quantitative investigation of the scalar Bethe-Salpeter equation in Minkowski space, within the ladder-approximation framework, is extended to include the excited states. This study has been carried out for an interacting system composed by two massive bosons exchanging a massive scalar, by adopting (i) the Nakanishi integral representation of the Bethe-Salpeter amplitude, and (ii) the formally exact projection onto the null plane. Our analysis, on one hand, confirms the reliability of the method already applied to the ground state and, on the other one, extends the investigation from the valence distribution in momentum space to the corresponding quantity in the impact-parameter space, pointing out some relevant features, like (i) the equivalence between Minkowski and Euclidean transverse-momentum amplitudes, and (ii) the leading exponential fall-off of the valence wave function in the impact-parameter space.
Bethe–Salpeter bound-state structure in Minkowski space
Energy Technology Data Exchange (ETDEWEB)
Gutierrez, C. [Instituto de Física Teórica, Universidade Estadual Paulista, 01156-970 São Paulo, SP (Brazil); Gigante, V.; Frederico, T. [Instituto Tecnológico de Aeronáutica, DCTA, 12.228-900 São José dos Campos, SP (Brazil); Salmè, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, P.le A. Moro 2, 00185 Roma (Italy); Viviani, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, Largo Pontecorvo 3, 56100 Pisa (Italy); Tomio, Lauro, E-mail: tomio@ift.unesp.br [Instituto de Física Teórica, Universidade Estadual Paulista, 01156-970 São Paulo, SP (Brazil); Instituto Tecnológico de Aeronáutica, DCTA, 12.228-900 São José dos Campos, SP (Brazil)
2016-08-10
The quantitative investigation of the scalar Bethe–Salpeter equation in Minkowski space, within the ladder-approximation framework, is extended to include the excited states. This study has been carried out for an interacting system composed by two massive bosons exchanging a massive scalar, by adopting (i) the Nakanishi integral representation of the Bethe–Salpeter amplitude, and (ii) the formally exact projection onto the null plane. Our analysis, on one hand, confirms the reliability of the method already applied to the ground state and, on the other one, extends the investigation from the valence distribution in momentum space to the corresponding quantity in the impact-parameter space, pointing out some relevant features, like (i) the equivalence between Minkowski and Euclidean transverse-momentum amplitudes, and (ii) the leading exponential fall-off of the valence wave function in the impact-parameter space.
Andreev Spectra and Subgap Bound States in Multiband Superconductors
Golubov, A. A.; Brinkman, A.; Tanaka, Yukio; Mazin, I.I.; Dolgov, O. V.
2009-01-01
The theory of Andreev conductance is formulated for junctions involving normal metals (N) and multiband superconductors (S) and applied to the case of superconductors with nodeless extended $s_{\\pm}$-wave order parameter symmetry, as possibly realized in the recently discovered ferro pnictides. We find qualitative differences from tunneling into s-wave or d-wave superconductors that may help to identify such a state. First, interband interference leads to a suppression of Andreev reflection i...
ABC Effect and Resonance Structure in the Double-Pionic Fusion to 3He
Directory of Open Access Journals (Sweden)
Pricking A.
2012-12-01
Full Text Available Historically the double-pionic fusion to 3He is the reaction, where the ABC effect (low-mass enhancement of the ππ-invariant mass spectrum was observed for the first time more than 50 years ago. Meanwhile exclusive and kinematically complete high-statistics measurements with WASA at COSY revealed a strict correlation between the ABC effect and a narrow resonance structure with I(JP = 0(3+ in the total cross section of the most basic double-pionic fusion, the pn → dπ0π0 reaction. In order to investigate the situation in the double-pionic fusion to 3He the energy dependence of the ABC effect in the fusion to 3He has been measured by fixed energy measurements of the type pd →3Heππ as well as by quasifree and coherent measurements of the type dd →3He n ππ.
Free energy barrier for melittin reorientation from a membrane-bound state to a transmembrane state
Irudayam, Sheeba J; 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 energy barrier. The PMFs were calculated for a peptide to lipid (P/L) ratio of 1/128 and 4/128. We observe that the free energy barrier is reduced when the P/L ratio increased. In addition, we study the cooperative effect; specifically we investigate if the barrier is smaller for a second melittin reorientation, given that another neighboring melittin was already in the transmembrane state. We observe that indeed the barrier of the PMF curve is reduced in this case, thus confirming the presence of a cooperative effect.
Bashkanov, M; Bargholtz, C; Berłowski, M; Bogoslawsky, D; Calén, H; Clement, H; Demiroers, L; Doroshkevich, E; Duniec, D; Ekström, C; Fransson, K; Geren, L; Gustafsson, L; Höistad, B; Ivanov, G; Jacewicz, M; Jiganov, E; Johansson, T; Khakimova, O; Keleta, S; Koch, I; Kren, F; Kullander, S; Kupść, A; Lindberg, K; Marciniewski, P; Meier, R; Morosov, B; Pauly, C; Pettersson, H; Petukhov, Y; Povtorejko, A; Pricking, A; Ruber, R J M Y; Schönning, K; Scobel, W; Shwartz, B; Skorodko, T; Sopov, V; Stepaniak, J; Tegner, P-E; Thörngren-Engblom, P; Tikhomirov, V; Turowiecki, A; Wagner, G J; Wolke, M; Zabierowski, J; Zartova, I; Złomanczuk, J
2009-02-06
The ABC effect-a puzzling low-mass enhancement in the pipi invariant mass spectrum, first observed by Abashian, Booth, and Crowe-is well known from inclusive measurements of two-pion production in nuclear fusion reactions. Here we report on the first exclusive and kinematically complete measurements of the most basic double-pionic fusion reaction pn-->dpi;{0}pi;{0} at beam energies of 1.03 and 1.35 GeV. The measurements, which have been carried out at CELSIUS-WASA, reveal the ABC effect to be a (pipi)_{I=L=0} channel phenomenon associated with both a resonancelike energy dependence in the integral cross section and the formation of a DeltaDelta system in the intermediate state. A corresponding simple s-channel resonance ansatz provides a surprisingly good description of the data.
Bashkanov, M.; Bargholtz, C.; Berłowski, M.; Bogoslawsky, D.; Calén, H.; Clement, H.; Demiroers, L.; Doroshkevich, E.; Duniec, D.; Ekström, C.; Fransson, K.; Geren, L.; Gustafsson, L.; Höistad, B.; Ivanov, G.; Jacewicz, M.; Jiganov, E.; Johansson, T.; Khakimova, O.; Keleta, S.; Koch, I.; Kren, F.; Kullander, S.; Kupść, A.; Lindberg, K.; Marciniewski, P.; Meier, R.; Morosov, B.; Pauly, C.; Pettersson, H.; Petukhov, Y.; Povtorejko, A.; Pricking, A.; Ruber, R. J. M. Y.; Schönning, K.; Scobel, W.; Shwartz, B.; Skorodko, T.; Sopov, V.; Stepaniak, J.; Tegner, P.-E.; Thörngren-Engblom, P.; Tikhomirov, V.; Turowiecki, A.; Wagner, G. J.; Wolke, M.; Zabierowski, J.; Zartova, I.; Złomanczuk, J.
2009-02-01
The ABC effect—a puzzling low-mass enhancement in the ππ invariant mass spectrum, first observed by Abashian, Booth, and Crowe—is well known from inclusive measurements of two-pion production in nuclear fusion reactions. Here we report on the first exclusive and kinematically complete measurements of the most basic double-pionic fusion reaction pn→dπ0π0 at beam energies of 1.03 and 1.35 GeV. The measurements, which have been carried out at CELSIUS-WASA, reveal the ABC effect to be a (ππ)I=L=0 channel phenomenon associated with both a resonancelike energy dependence in the integral cross section and the formation of a ΔΔ system in the intermediate state. A corresponding simple s-channel resonance ansatz provides a surprisingly good description of the data.
Fingerprint of topological Andreev bound states in phase-dependent heat transport
Sothmann, Björn; Hankiewicz, Ewelina M.
2016-08-01
We demonstrate that phase-dependent heat currents through superconductor-topological insulator Josephson junctions provide a useful tool to probe the existence of topological Andreev bound states, even for multichannel surface states. We predict that in the tunneling regime topological Andreev bound states lead to a minimum of the thermal conductance for a phase difference ϕ =π , in clear contrast to a maximum of the thermal conductance at ϕ =π that occurs for trivial Andreev bound states in superconductor-normal-metal tunnel junctions. This opens up the possibility that phase-dependent heat transport can distinguish between topologically trivial and nontrivial 4 π modes. Furthermore, we propose a superconducting quantum interference device geometry where phase-dependent heat currents can be measured using available experimental technology.
Tunable Plasmonic Reflection by Bound 1D Electron States in a 2D Dirac Metal.
Jiang, B-Y; Ni, G X; Pan, C; Fei, Z; Cheng, B; Lau, C N; Bockrath, M; Basov, D N; Fogler, M M
2016-08-19
We show that the surface plasmons of a two-dimensional Dirac metal such as graphene can be reflected by linelike perturbations hosting one-dimensional electron states. The reflection originates from a strong enhancement of the local optical conductivity caused by optical transitions involving these bound states. We propose that the bound states can be systematically created, controlled, and liquidated by an ultranarrow electrostatic gate. Using infrared nanoimaging, we obtain experimental evidence for the locally enhanced conductivity of graphene induced by a carbon nanotube gate, which supports this theoretical concept.
X(3872) and Bound State Problem of D~0(D)*~0((D)~0D*~0)
Institute of Scientific and Technical Information of China (English)
LIU Tan-rui; LIU Xiang; DENG Wei-zhen
2009-01-01
We have performed a dynamical calculation of the bound state problem of D~0(D)~(*0) by considering the pion and sigma meson exchange potential.Our preliminary analysis disfavors the molecular interpretation of X(3872) if we use the experimental D~* Dπ coupling constant g=0.59 and a reasonable cutoff around 1 GeV,which is the typical hadronic scale.In contrast,there probably exists a loosely bound S-wave B (-B)~* molecular state.Such a molecular state would be rather stable since its dominant decay mode is the radiative decay through B~*→Bγ.
Tunable Plasmonic Reflection by Bound 1D Electron States in a 2D Dirac Metal
Jiang, B.-Y.; Ni, G. X.; Pan, C.; Fei, Z.; Cheng, B.; Lau, C. N.; Bockrath, M.; Basov, D. N.; Fogler, M. M.
2016-08-01
We show that the surface plasmons of a two-dimensional Dirac metal such as graphene can be reflected by linelike perturbations hosting one-dimensional electron states. The reflection originates from a strong enhancement of the local optical conductivity caused by optical transitions involving these bound states. We propose that the bound states can be systematically created, controlled, and liquidated by an ultranarrow electrostatic gate. Using infrared nanoimaging, we obtain experimental evidence for the locally enhanced conductivity of graphene induced by a carbon nanotube gate, which supports this theoretical concept.
Study of BB ¯*/DD ¯* bound states in a Bethe-Salpeter approach
He, Jun
2014-10-01
In this work the BB ¯*/DD ¯* system is studied in the Bethe-Salpeter approach with quasipotential approximation. In our calculation both direct and cross diagrams are included in the one-boson-exchange potential. The numerical results indicate the existence of an isoscalar bound state DD ¯* with JPC=1++, which may be related to the X(3872). In the isovector sector, no bound state is produced from the interactions of DD ¯* and BB ¯*, which suggests the molecular state explanations for Zb(10610) and Zc(3900) are excluded.
In-medium mathaccent "7016relax K- and eta -meson Interactions and Bound States
Gal, A.; Friedman, E.; Barnea, N.; Cieplý, A.; Mareš, J.; Gazda, D.
The role played by subthreshold meson-baryon dynamics is demonstrated in kaonic-atom, Kbar-nuclear and eta-nuclear bound-state calculations within in-medium models of Kbar-N and eta-N interactions. New analyses of kaonic atom data reveal appreciable multi-nucleon contributions. Calculations of eta-nuclear bound states show, in particular, that the eta-N scattering length is not a useful indicator of whether or not eta mesons bind in nuclei nor of the widths anticipated for such states.
Andreev and Majorana bound states in single and double quantum dot structures
Silva, Joelson F.; Vernek, E.
2016-11-01
We present a numerical study of the emergence of Majorana and Andreev bound states in a system composed of two quantum dots, one of which is coupled to a conventional superconductor, SC1, and the other connects to a topological superconductor, SC2. By controlling the interdot coupling we can drive the system from two single (uncoupled) quantum dots to double (coupled) dot system configurations. We employ a recursive Green’s function technique that provides us with numerically exact results for the local density of states of the system. We first show that in the uncoupled dot configuration (single dot behavior) the Majorana and the Andreev bound states appear in an individual dot in two completely distinct regimes. Therefore, they cannot coexist in the single quantum dot system. We then study the coexistence of these states in the coupled double dot configuration. In this situation we show that in the trivial phase of SC2, the Andreev states are bound to an individual quantum dot in the atomic regime (weak interdot coupling) or extended over the entire molecule in the molecular regime (strong interdot coupling). More interesting features are actually seen in the topological phase of SC2. In this case, in the atomic limit, the Andreev states appear bound to one of the quantum dots while a Majorana zero mode appears in the other one. In the molecular regime, on the other hand, the Andreev bound states take over the entire molecule while the Majorana state remains always bound to one of the quantum dots.
Search for $\\eta$'(958)-nucleus bound states by (p,d) reaction at GSI and FAIR
Fujioka, H; Benlliure, J; Brinkmann, K -T; Friedrich, S; Geissel, H; Gellanki, J; Guo, C; Gutz, E; Haettner, E; Harakeh, M N; Hayano, R S; Higashi, Y; Hirenzaki, S; Hornung, C; Igarashi, Y; Ikeno, N; Itahashi, K; Iwasaki, M; Jido, D; Kalantar-Nayestanaki, N; Kanungo, R; Knoebel, R; Kurz, N; Metag, V; Mukha, I; Nagae, T; Nagahiro, H; Nanova, M; Nishi, T; Ong, H J; Pietri, S; Prochazka, A; Rappold, C; Reiter, M P; Rodríguez-Sánchez, J L; Scheidenberger, C; Simon, H; Sitar, B; Strmen, P; Sun, B; Suzuki, K; Szarka, I; Takechi, M; Tanaka, Y K; Tanihata, I; Terashima, S; Watanabe, Y N; Weick, H; Widmann, E; Winfield, J S; Xu, X; Yamakami, H; Zhao, J
2015-01-01
The mass of the {\\eta}' meson is theoretically expected to be reduced at finite density, which indicates the existence of {\\eta}'-nucleus bound states. To investigate these states, we perform missing-mass spectroscopy for the (p, d) reaction near the {\\eta}' production threshold. The overview of the experimental situation is given and the current status is discussed.
Normalization and perturbation theory for tightly bound states of the spinor Bethe-Salpeter equation
L.G. Suttorp
1976-01-01
The normalisation integrals for the tightly-bound-state solutions of the spinor Bethe-Salpeter equation that have been derived recently are evaluated. Ghost states are found to appear when the continuous parameters characterising the type of fermion-boson interaction reach a critical value. Perturba
Rapisarda, P.; Trentelman, H.L.; Minh, H.B.
2013-01-01
We illustrate an algorithm that starting from the image representation of a strictly bounded-real system computes a minimal balanced state variable, from which a minimal balanced state realization is readily obtained. The algorithm stems from an iterative procedure to compute a storage function, bas
Explicit formula for the Holevo bound for two-parameter qubit-state estimation problem
Suzuki, Jun
2016-04-01
The main contribution of this paper is to derive an explicit expression for the fundamental precision bound, the Holevo bound, for estimating any two-parameter family of qubit mixed-states in terms of quantum versions of Fisher information. The obtained formula depends solely on the symmetric logarithmic derivative (SLD), the right logarithmic derivative (RLD) Fisher information, and a given weight matrix. This result immediately provides necessary and sufficient conditions for the following two important classes of quantum statistical models; the Holevo bound coincides with the SLD Cramér-Rao bound and it does with the RLD Cramér-Rao bound. One of the important results of this paper is that a general model other than these two special cases exhibits an unexpected property: the structure of the Holevo bound changes smoothly when the weight matrix varies. In particular, it always coincides with the RLD Cramér-Rao bound for a certain choice of the weight matrix. Several examples illustrate these findings.
Short-lived two-soliton bound states in weakly perturbed nonlinear Schrodinger equation.
Dmitriev, Sergey V.; Shigenari, Takeshi
2002-06-01
Resonant soliton collisions in the weakly discrete nonlinear Schrodinger equation are studied numerically. The fractal nature of the soliton scattering, described in our previous works, is investigated in detail. We demonstrate that the fractal scattering pattern is related to the existence of the short-lived two-soliton bound states. The bound state can be regarded as a two-soliton quasiparticle of a new type, different from the breather. We establish that the probability P of a bound state with the lifetime L follows the law P approximately L(-3). In the frame of a simple two-particle model, we derive the nonlinear map, which generates the fractal pattern similar to that observed in the numerical study of soliton collisions. (c) 2002 American Institute of Physics.
Majorana bound state in a coupled quantum-dot hybrid-nanowire system
Deng, M. T.; Vaitiekėnas, S.; Hansen, E. B.; Danon, J.; Leijnse, M.; Flensberg, K.; Nygård, J.; Krogstrup, P.; Marcus, C. M.
2016-12-01
Hybrid nanowires combining semiconductor and superconductor materials appear well suited for the creation, detection, and control of Majorana bound states (MBSs). We demonstrate the emergence of MBSs from coalescing Andreev bound states (ABSs) in a hybrid InAs nanowire with epitaxial Al, using a quantum dot at the end of the nanowire as a spectrometer. Electrostatic gating tuned the nanowire density to a regime of one or a few ABSs. In an applied axial magnetic field, a topological phase emerges in which ABSs move to zero energy and remain there, forming MBSs. We observed hybridization of the MBS with the end-dot bound state, which is in agreement with a numerical model. The ABS/MBS spectra provide parameters that are useful for understanding topological superconductivity in this system.
Widths of K¯-nuclear deeply bound states in a dynamical model
Mareš, J.; Friedman, E.; Gal, A.
2005-01-01
The relativistic mean field (RMF) model is applied to a system of nucleons and a Kbar meson, interacting via scalar and vector boson fields. The model incorporates the standard RMF phenomenology for bound nucleons and, for the Kbar meson, it relates to low-energy Kbar N and K- atom phenomenology. Deeply bound Kbar nuclear states are generated dynamically across the periodic table and are exhibited for 12C and 16O over a wide range of binding energies. Substantial polarization of the core nucleus is found for these light nuclei. Absorption modes are also included dynamically, considering explicitly both the resulting compressed nuclear density and the reduced phase space for Kbar absorption from deeply bound states. The behavior of the calculated width as function of the Kbar binding energy is studied in order to explore limits on the possible existence of narrow Kbar nuclear states.
A Pionic Hadron Explains the Muon Magnetic Moment Anomaly
Schiel, Rainer W
2007-01-01
Quantum electrodynamics is the most successful physical theory in history. Yet for several years a significant experimental discrepancy has existed. Calculations disagree with measurements of the muon's magnetic moment, which is a fundamental test of the theory. A new contribution hidden in plain view explains the current discrepancy. Mixing of the rho meson and pionium, the bound state atom of pion and anti-pion, must be treated as a new elementary particle, the second least-massive hadron. Surprisingly, the existence of the particle state is undeniable. Yet superposition of pionium and rho must contradict basic assumptions of pion physics, and may be the first case in which an orbitally asymmetric hadron has mass below the symmetric case, due to quark microstructure that cannot be described by pions at all.
Bound entanglement and entanglement bounds
Energy Technology Data Exchange (ETDEWEB)
Sauer, Simeon [Physikalisch-Astronomische Fakultaet, Friedrich-Schiller-Univesitaet Jena (Germany)]|[Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg (Germany); Melo, Fernando de; Mintert, Florian; Buchleitner, Andreas [Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg (Germany)]|[Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Str.38, D-01187 Dresden (Germany); Bae, Joonwoo [School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-012 (Korea); Hiesmayr, Beatrix [Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria)
2008-07-01
We investigate the separability of Bell-diagonal states of two qutrits. By using lower bounds to algebraically estimate concurrence, we find convex regions of bound entangled states. Some of these regions exactly coincide with the obtained results when employing optimal entanglement witnesses, what shows that the lower bound can serve as a precise detector of entanglement. Some hitherto unknown regions of bound entangled states were discovered with this approach, and delimited efficiently.
Lorentz contraction of bound states in 1+1 dimensional gauge theory
Järvinen, M.
2004-09-01
We consider the Lorentz contraction of a fermion-antifermion bound state in 1+1 dimensional QED. In 1+1 dimensions the absence of physical, propagating photons allows us to explicitly solve the weak coupling limit α≪m2 of the Bethe-Salpeter bound state equation in any Lorentz frame. In a time-ordered formalism it is seen that all pair production is suppressed in this limit. The wave function is shown to contract while the mass spectrum is invariant under boosts.
The Analogue of the Aharonov-Bohm Effect for Bound States for Neutral Particles
Bakke, Knut; Furtado, C.
We study the analogue of the Aharonov-Bohm effect for bound states for a neutral particle with a permanent magnetic dipole moment interacting with an external field. We consider a neutral particle confined to moving between two coaxial cylinders and show the dependence of the energy levels on the Aharonov-Casher quantum flux. Moreover, we show that the same flux dependence of the bound states can be found when the neutral particle is confined to a one-dimensional quantum ring and a quantum dot, and we also calculate the persistent currents in each case.
Bound states of the $\\phi^4$ model via the Non-Perturbative Renormalization Group
Rose, F; Leonard, F; Delamotte, B
2016-01-01
Using the nonperturbative renormalization group, we study the existence of bound states in the symmetry-broken phase of the scalar $\\phi^4$ theory in all dimensions between two and four and as a function of the temperature. The accurate description of the momentum dependence of the two-point function, required to get the spectrum of the theory, is provided by means of the Blaizot--M\\'endez-Galain--Wschebor approximation scheme. We confirm the existence of a bound state in dimension three, with a mass within 1% of previous Monte-Carlo and numerical diagonalization values.
The Relativistic Three-Body Bound State in Three-Dimensions
Directory of Open Access Journals (Sweden)
Hadizadeh M. R.
2016-01-01
Full Text Available Studying of the relativistic three-body bound state in a three-dimensional (3D approach is a necessary first step in a process to eventually perform scattering calculations at GeV energies, where partial-wave expansions are not useful. To this aim we recently studied relativistic effects in the binding energy and for the first time, obtained the relativistic 3B wave function [1]. The relativistic Faddeev integral equations for the bound state are formulated in terms of momentum vectors, and relativistic invariance is incorporated within the framework of Poincaré invariant quantum mechanics.
Upper Bounds on the Degeneracy of the Ground State in Quantum Field Models
Directory of Open Access Journals (Sweden)
Asao Arai
2016-01-01
Full Text Available Axiomatic abstract formulations are presented to derive upper bounds on the degeneracy of the ground state in quantum field models including massless ones. In particular, given is a sufficient condition under which the degeneracy of the ground state of the perturbed Hamiltonian is less than or equal to the degeneracy of the ground state of the unperturbed one. Applications of the abstract theory to models in quantum field theory are outlined.
Study of hyperfine structure in simple atoms and precision tests of the bound state QED
Energy Technology Data Exchange (ETDEWEB)
Karshenboim, S.G. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); D.I. Mendeleev Institute for Metrology (VNIIM), St. Petersburg 190005 (Russian Federation); Eidelman, S.I. [Budker Institute for Nuclear Physics and Novosibirsk State University, Novosibirsk, 630090 (Russian Federation); Fendel, P. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); Ivanov, V.G. [Pulkovo Observatory, St. Petersburg 196140 (Russian Federation); Kolachevsky, N.N. [P.N. Lebedev Physics Institute, Moscow, 119991 (Russian Federation); Shelyuto, V.A. [D.I. Mendeleev Institute for Metrology (VNIIM), St. Petersburg 190005 (Russian Federation); Haensch, T.W. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany)
2006-12-15
We consider the most accurate tests of bound state QED, precision theory of simple atoms, related to the hyperfine splitting in light hydrogen-like atoms. We discuss the HFS interval of the 1s state in muonium and positronium and of the 2s state in hydrogen, deuterium and helium-3 ion. We summarize their QED theory and pay attention to involved effects of strong interactions. We also consider recent optical measurements of the 2s HFS interval in hydrogen and deuterium.
Study of hyperfine structure in simple atoms and precision tests of the bound state QED
Karshenboim, S G; Fendel, P; Ivanov, V G; Kolachevsky, N N; Shelyuto, V A; Hänsch, T W
2006-01-01
We consider the most accurate tests of bound state QED, precision theory of simple atoms, related to the hyperfine splitting in light hydrogen-like atoms. We discuss the HFS interval of the 1s state in muonium and positronium and of the 2s state in hydrogen, deuterium and helium-3 ion. We summarize their QED theory and pay attention to involved effects of strong interactions. We also consider recent optical measurements of the 2s HFS interval in hydrogen and deuterium.
Ikot, A. N.; Obong, H. P.; Abbey, T. M.; Zare, S.; Ghafourian, M.; Hassanabadi, H.
2016-09-01
In this article we use supersymmetry quantum mechanics and factorization methods to study the bound and scattering state of Klein-Gordon equation with deformed Hulthen plus deformed hyperbolical potential for arbitrary state in D-dimensions. The analytic relativistic bound state eigenvalues and the scattering phase factor are found in closed form. We report on the numerical results for the bound state energy in D-dimensions.
Investigation of the $nn\\Lambda$ bound state in pionless effective theory
Ando, Shung-Ichi; Oh, Yongseok
2015-01-01
The possibility of an $nn\\Lambda$ bound state is investigated in the framework of pionless effective field theory at leading order. A system of coupled integral equations are constructed in the spin-isospin basis, of which numerical solutions are investigated. In particular, we make use of the limit cycle behavior, i.e., cyclic singularities of coupled integral equations of the system, which would be associated with the formation of a three-body bound state, so-called the Efimov state, in the unitary limit. Furthermore, we find that, when the sharp momentum cutoff introduced in the integral equations is taken significantly larger than the hard scale of the effective theory, the coupling of a three-body contact interaction becomes cyclically singular indicating the onset of Efimov-like bound state formation. However, the paucity of empirical information to determine the parameters of the theory precludes a definitive conclusion on the existence of such a bound state. As a simple test of the feasibility of the ...
Formation of deeply bound LiRb molecules via photoassociation to near asymptotic states
Lorenz, John D.
We present the results of a spectroscopic study LiRb molecules created via photoassociation (PA) to vibration levels of the 4(1) potential. Atoms are first cooled and trapped in a dual species 7Li/ 85Rb magneto-optical trap (MOT) at temperatures of ≈ 1 mK or less. In a cold sample of sufficient density, PA occurs when a resonant laser field induces a free-bound transition to create molecules in an excited electronic potential. After spontaneous emission the molecules decay to a mixture of free atoms and bound molecules depending on the Franck-Condon factors (FCFs) of the excited and ground state vibrational wavefunctions. While excited LiRb * has been previously detected by trap loss fluorescence detection, ionization spectroscopy is required to determine the population of ground state levels after decay. We detect ground state molecules via resonantly enhanced multiphoton ionization (REMPI) where a two photon ionization transition is enhanced by an intermediate resonance. The intermediate resonances match progressions from the D1pi and possibly B1Π potentials, many of which have known energies obtained from previous heat pipe experiments. This is contrary to the expectation that weakly bound LiRb * should primarily decay to weakly bound levels of the ground state and could point to a possible path for creating molecules in the rovibronic ground state.
Manipulation of Squeezed Two-Phonon Bound States using Femtosecond Laser Pulses
Directory of Open Access Journals (Sweden)
Nakamura Kazutaka G.
2013-03-01
Full Text Available Two-phonon bound states have been excited exclusively in ZnTe(110 via impulsive stimulated second-order Raman scattering, essentially being squeezed states due to phase coherent excitation of two identical components anticorrelated in the wave vector. By using coherent control technique with a pair of femtosecond laser pulses, the manipulation of squeezed states has been demonstrated in which both the amplitude and lifetime of coherent oscillations of squeezed states are modulated, indicating the feasibility to control the quantum noise and the quantum nature of phonon squeezed states, respectively.
Aspects of Majorana Bound States in One-Dimensional Systems with and without Time-Reversal Symmetry
DEFF Research Database (Denmark)
Wölms, Konrad Udo Hannes
bound states in the measurement still has to be understood better. And example would be the frequently performed tunnel probe measurement on Majorana bound states [26, 40, 41]. A second reason why Majorana bound states are interesting is their potential application to a certain quantum computation...... scheme. This scheme, called topological quantum computation, relies on the braiding of so-called non-abelian anyons in order to perform computations [18]. Majorana bound states are the simplest example of such non-abelian anyons. No other non-abelian anyons have been realized experimentally yet, which...... puts further focus on the study of Majorana bound states. Additionally to probing Majorana bound states, their use in topological quantum computation also requires them to be manipulated. This also poses an interesting problem for both experimentalists and theorists [25, 27]. We can summarize...
Onyeaju, M. C.; Ikot, A. N.; Chukwuocha, E. O.; Obong, H. P.; Zare, S.; Hassanabadi, H.
2016-09-01
Scattering and bound states solution for the one-dimensional Klein-Gordon particle with Hylleraas potential is presented within the frame work of position dependent effective mass formalism. We calculate in detail the reflection and transmission coefficients using the properties of hypergeometric functions and the equation of continuity of the wave functions.
Bound States of the S-Wave Equation with Equal Scalar and Vector Standard Eckart Potential
Institute of Scientific and Technical Information of China (English)
Eser Ol(g)ar; Ramazan Ko(c); Hayriye Tütüncüler
2006-01-01
@@ A supersymmetric technique for the bound-state solutions of the s-wave Klein-Gordon equation with equal scalar and vector standard Eckart-type potential is proposed. Its exact solutions are obtained. Possible generalization of our approach is outlined.
Resonances from QCD bound states and the 750 GeV diphoton excess
Kats, Yevgeny
2016-01-01
Pair production of colored particles is in general accompanied by production of QCD bound states (onia) slightly below the pair-production threshold. Bound state annihilation leads to resonant signals, which in some cases are easier to see than the decays of the pair-produced constituents. In a previous paper (arXiv:1204.1119) we estimated the bound state signals, at leading order and in the Coulomb approximation, for particles with various spins, color representations and electric charges, and used 7 TeV ATLAS and CMS resonance searches to set rough limits. Here we update our results to include 8 and 13 TeV data. We find that the recently reported diphoton excesses near 750 GeV could indeed be due to a bound state of this kind. A narrow resonance of the correct size could be obtained for a color-triplet scalar with electric charge -4/3 and mass near 375 GeV, if (as a recent lattice computation suggests) the wave function at the origin is somewhat larger than anticipated. Pair production of this particle coul...
Spin(p+1, p+1) covariant Dp-brane bound states
Sundell, P
2001-01-01
We construct Spin(p + 1, p + 1) covariant Dp-brane bound states by using the fact that the potentials in the RR sector of toroidically compactified type Ii supergravity transform as a chiral spinor of the T duality group. As an application, we show the invariance of the zero-force condition for a pr
The Need for an Upward Bound Project at Bowie State College.
Gill, Wanda E.
Reasons that Bowie State College in Maryland should participate in the Upward Bound Project are discussed, with attention to geographic and demographic characteristics of the area, school characteristics, and needed services. The college historically has provided educational opportunities for black, disadvantaged students and has been successful…
Liu, H; Glöckle, W; Elster, Ch.
2002-01-01
The Faddeev equations for the three-body bound state are solved directly as thre e-dimensional integral equations without employing partial wave decomposition. Two-body forces of the Malfliet-Tjon type and simple spin independent genuine three-body forces are considered for the calculation of the three-body binding energy.
Precision study of positronium and precision tests of the bound state QED
Karshenboim, Savely G.
2002-01-01
Despite its very short lifetime positronium provides us with a number of accurate tests of the bound state QED. In this note a brief overview of QED theory and precision experiments on the spectrum and annihilation decay of the positronium atom is presented. Special attention is paid to the accuracy of theoretical predictions.
Bound State Solutions of Klein-Gordon Equation with the Kratzer Potential
Institute of Scientific and Technical Information of China (English)
M. Ko(c)ak
2007-01-01
The relativistic problem of spinless particle subject to a Kratzer potential is analysed. Bound state solutions for s-waves are found by separating the Klein-Gordon equation into two parts. Unlike the similar works in the literature, the separation make it possible to see explicitly the relativistic contributions, if any, to the solution in the non-relativistic limit.
Exact solutions of the spinor Bethe-Salpeter equation for tightly bound states
Suttorp, L.G.
1975-01-01
Exact solutions are obtained for the spinor Bethe-Salpeter equation that describes tightly bound states of spin-/sup 1///sub 2/ fermions with massless-boson exchange. The corresponding coupling constants form a discrete spectrum that depends continuously on the parameters characterizing the type of
Light Fermion Finite Mass Effects in Non-relativistic Bound States
Eiras, D; Eiras, Dolors; Soto, Joan
2000-01-01
We present analytic expressions for the vacuum polarization effects due to a light fermion with finite mass in the binding energy and in the wave function at the origin of QED and (weak coupling) QCD non-relativistic bound states. Applications to exotic atoms, \\Upsilon (1s) and t\\bar{t} production near threshold are briefly discussed.
Charmed mesic nuclei Bound D and over D states with 208Pb
Tsushima, K; Thomas, A W; Saitô, K; Landau, Rubin H
1999-01-01
We show that the $D^-$ meson will inevitably form narrow bound states with $^{208}$Pb. The experimental confirmation and comparison with the $\\bar{D}^0$ and $D^0$ will provide distinctive information on the nature of the interaction between the charmed meson and matter.
Bakke, K.
2010-10-01
We obtain the solutions of the Dirac equation when the noninertial effects of the Fermi-Walker reference frame break the relativistic Landau-Aharonov-Casher quantization, but they provide bound states in an analogous way to a Dirac neutral particle subject to Tan-Inkson quantum dot potential [W.-C. Tan, J.C. Inkson, Semicond. Sci. Technol. 11 (1996) 1635].
On the energy of bound states for magnetic Schrödinger operators
DEFF Research Database (Denmark)
Fournais, Søren; Kachmar, Ayman
2009-01-01
We provide a leading order semiclassical asymptotics of the energy of bound states for magnetic Neumann Schrödinger operators in two-dimensional (exterior) domains with smooth boundaries. The asymptotics is valid all the way up to the bottom of the essential spectrum. When the spectral parameter...
The Bound State S-matrix of the Deformed Hubbard Chain
de Leeuw, Marius; Matsumoto, Takuya
2011-01-01
In this work we use the q-oscillator formalism to construct the atypical (short) supersymmetric representations of the centrally extended Uq (su(2|2)) algebra. We then determine the S-matrix describing the scattering of arbitrary bound states. The crucial ingredient in this derivation is the affine extension of the aforementioned algebra.
Applying the relativistic quantization condition to a three-particle bound state in a periodic box
Hansen, Maxwell T
2016-01-01
Using our recently developed relativistic three-particle quantization condition, we study the finite-volume energy shift of a three-particle bound state. We reproduce the result obtained using non-relativistic quantum mechanics by Mei{\\ss}ner, R{\\'i}os and Rusetsky, and generalize the result to a moving frame.
Bound state transfer matrix for AdS5 × S5 superstring
Arutyunov, G.E.; de Leeuw, M.; Suzuki, R.; Torrielli, A.
2009-01-01
We apply the algebraic Bethe ansatz technique to compute the eigenvalues of the transfer matrix constructed from the general bound state S-matrix of the light-cone AdS5 × S5 superstring. This allows us to verify certain conjectures on the quantum characteristic function, and to extend them to the ge
Bound states of the Dirac equation with some physical potentials by the Nikiforov-Uvarov method
Energy Technology Data Exchange (ETDEWEB)
Setare, Mohammad R; Haidari, S [Department of Physics, University of Kurdistan, Pasdaran Avenue, Sanandaj (Iran, Islamic Republic of)], E-mail: rezakord@ipm.ir, E-mail: heidary.somayeh@gmail.com
2010-01-15
Exact analytical solutions for the s-wave Dirac equation with the reflectionless-type, Rosen-Morse and Manning-Rosen potentials are obtained, under the condition of spin symmetry. We obtained bound state energy eigenvalues and corresponding spinor wave function in the framework of the Nikiforov-Uvarov (NU) method.
Resonances from QCD bound states and the 750 GeV diphoton excess
Kats, Yevgeny; Strassler, Matthew J.
2016-05-01
Pair production of colored particles is in general accompanied by production of QCD bound states (onia) slightly below the pair-production threshold. Bound state annihilation leads to resonant signals, which in some cases are easier to see than the decays of the pair-produced constituents. In a previous paper ( arXiv:1204.1119 URL"/> ) we estimated the bound state signals, at leading order and in the Coulomb approximation, for particles with various spins, color representations and electric charges, and used 7 TeV ATLAS and CMS resonance searches to set rough limits. Here we update our results to include 8 and 13 TeV data. We find that the recently reported diphoton excesses near 750 GeV could indeed be due to a bound state of this kind. A narrow resonance of the correct size could be obtained for a color-triplet scalar with electric charge -4/3 and mass near 375GeV, if (as a recent lattice computation suggests) the wave function at the origin is somewhat larger than anticipated. Pair production of this particle could have evaded detection up to now. Other candidates may include a triplet scalar of charge 5/3, a triplet fermion of charge -4/3, and perhaps a sextet scalar of charge -2/3.
A new interpretation of the proton-neutron bound state The calculation of the binding energy
Mandache, N
1996-01-01
We treat the old problem of the proton-neutron bound state (the deuteron). Using a new concept of incomplete (partial) annihilation process we derive a formula for the binding energy of the deuteron, which does not contain any new constant. Some implications of this new approach are discussed.
ηN interactions in the nuclear medium. η-nuclear bound states
Mareš, J.; Barnea, N.; Cieplý, A.; Friedman, E.; Gal, A.
2016-11-01
We report on our recent study of in-medium ηN interactions and η-nuclear quasi-bound states. The ηN scattering amplitudes considered in the calculations are constructed within coupled-channel models that incorporate the S11 N*(1535) resonance. The implications of self-consistent treatment and the role played by subthreshold dynamics are discussed.
Delayed birth of distillable entanglement in the evolution of bound entangled states
Derkacz, Łukasz
2010-01-01
The dynamical creation of entanglement between three-level atoms coupled to the common vacuum is investigated. For the class of bound entangled initial states we show that the dynamics of closely separated atoms generates stationary distillable entanglement of asymptotic states. We also find that the effect of delayed sudden birth of distillable entanglement occurs in the case of atoms separated by a distance comparable with the radiation wavelength.
Reflection algebra, Yangian symmetry and bound-states in AdS/CFT
MacKay, Niall
2011-01-01
We present the `Heisenberg picture' of the reflection algebra by explicitly constructing the boundary Yangian symmetry of the AdS/CFT superstring ending on a boundary with degrees of freedom and preserving all of the bulk symmetry algebra. This enables us to present the bound-state reflection matrices in a more elegant, rapidity-difference form. We also consider the spectrum of bulk and boundary states and some automorphisms of the underlying algebras.
Bounds on probability of state transfer with respect to readout time and edge weight
Gordon, Whitney; Kirkland, Steve; Li, Chi-Kwong; Plosker, Sarah; Zhang, Xiaohong
2016-02-01
We analyze the sensitivity of a spin chain modeled by an undirected weighted connected graph exhibiting perfect state transfer to small perturbations in readout time and edge weight in order to obtain physically relevant bounds on the probability of state transfer. At the heart of our analysis is the concept of the numerical range of a matrix; our analysis of edge weight errors additionally makes use of the spectral and Frobenius norms.
Scattering resonances and two-particle bound states of the extended Hubbard model
Energy Technology Data Exchange (ETDEWEB)
Valiente, M; Petrosyan, D [Institute of Electronic Structure and Laser, FORTH, 71110 Heraklion, Crete (Greece)
2009-06-28
We present a complete derivation of two-particle states of the one-dimensional extended Bose-Hubbard model involving attractive or repulsive on-site and nearest-neighbour interactions. We find that this system possesses scattering resonances and two families of energy-dependent interaction-bound states which are not present in the Hubbard model with the on-site interaction alone. (fast track communication)
Reduced adiabatic hyperspherical basis in the Coulomb three-body bound state problem
Energy Technology Data Exchange (ETDEWEB)
Abramov, D.I. [Sankt Peterburgskij Univ., St. Petersburg (Russian Federation); Gusev, V.V. [Institut Fiziki Vysokikh Ehnergij, Protvino (Russian Federation); Ponomarev, L.I. [Rossijskij Nauchnyj Tsentr ``Kurchatovskij Inst.``, Moscow (Russian Federation)
1996-10-01
A new version of the adiabatic hyperspherical approach (AHSA) is suggested which has significant advantages for the calculation of three-body states with total angular momentum J > 0. The binding energies of all bound states of mesic molecules with normal parity are calculated by the suggested method. Comparison with results of variational calculations and the fast convergence of the method confirm its high efficiency. (orig.). 13 refs.
Tight bound on coherent-state-based entanglement generation over lossy channels
Azuma, Koji; Koashi, Masato; Imoto, Nobuyuki
2009-01-01
The first stage of the hybrid quantum repeaters is entanglement generation based on transmission of pulses in coherent states over a lossy channel. Protocols to make entanglement with only one type of error are favorable for rendering subsequent entanglement distillation efficient. Here we provide the tight upper bound on performances of these protocols that is determined only by the channel loss. In addition, we show that this bound is achievable by utilizing a proposed protocol [arXiv:0811.3100] composed of a simple combination of linear optical elements and photon-number-resolving detectors.
Lower bounds for ballistic current and noise in non-equilibrium quantum steady states
Directory of Open Access Journals (Sweden)
Benjamin Doyon
2015-03-01
Full Text Available Let an infinite, homogeneous, many-body quantum system be unitarily evolved for a long time from a state where two halves are independently thermalized. One says that a non-equilibrium steady state emerges if there are nonzero steady currents in the central region. In particular, their presence is a signature of ballistic transport. We analyze the consequences of the current observable being a conserved density; near equilibrium this is known to give rise to linear wave propagation and a nonzero Drude peak. Using the Lieb–Robinson bound, we derive, under a certain regularity condition, a lower bound for the non-equilibrium steady-state current determined by equilibrium averages. This shows and quantifies the presence of ballistic transport far from equilibrium. The inequality suggests the definition of “nonlinear sound velocities”, which specialize to the sound velocity near equilibrium in non-integrable models, and “generalized sound velocities”, which encode generalized Gibbs thermalization in integrable models. These are bounded by the Lieb–Robinson velocity. The inequality also gives rise to a bound on the energy current noise in the case of pure energy transport. We show that the inequality is satisfied in many models where exact results are available, and that it is saturated at one-dimensional criticality.
Bound states of massive fermions in Aharonov-Bohm-like fields
Energy Technology Data Exchange (ETDEWEB)
Khalilov, V.R. [Moscow State University, Faculty of Physics, Moscow (Russian Federation)
2014-01-15
Bound states of massive fermions in Aharonov-Bohm (AB)-like fields have analytically been studied. The Hamiltonians with the (AB)-like potentials are essentially singular and therefore require specification of a one-parameter self-adjoint extension. We construct self-adjoint Dirac Hamiltonians with the AB potential in 2+1 dimensions that are specified by boundary conditions at the origin. It is of interest that for some range of the extension parameter the AB potential can bind relativistic charged massive fermions. The bound-state energy is determined by the AB magnetic flux and depends upon the fermion spin and extension parameter; it is a periodical function of the magnetic flux. We also construct self-adjoint Hamiltonians for the so-called Aharonov-Casher (AC) problem, show that nonrelativistic neutral massive fermions can be bound by the (AC) background, determine the range of the extension parameter in which fermion bound states exist, and find their energies as well as wave functions. (orig.)
Lower bounds for the ground-state degeneracies of frustrated systems on fractal lattices
Curado; Nobre
2000-12-01
The total number of ground states for nearest-neighbor-interaction Ising systems with frustrations, defined on hierarchical lattices, is investigated. A simple method is presented, which allows one to factorize the ground-state degeneracy, at a given hierarchy level n, in terms of contributions due to all hierarchy levels. Such a method may yield the exact ground-state degeneracy of uniformly frustrated systems, whereas it works as an approximation for randomly frustrated models. In the latter cases, it is demonstrated that such an approximation yields lower-bound estimates for the ground-state degeneracies.
Ionization and bound-state relativistic quantum dynamics in laser-driven multiply charged ions
Energy Technology Data Exchange (ETDEWEB)
Hetzheim, Henrik
2009-01-14
The interaction of ultra-strong laser fields with multiply charged hydrogen-like ions can be distinguished in an ionization and a bound dynamics regime. Both are investigated by means of numerically solving the Dirac equation in two dimensions and by a classical relativistic Monte-Carlo simulation. For a better understanding of highly nonlinear physical processes the development of a well characterized ultra-intense relativistic laser field strength has been driven forward, capable of studying e.g. the magnetic field effects of the laser resulting in an additional electron motion in the laser propagation direction. A novel method to sensitively measure these ultra-strong laser intensities is developed and employed from the optical via the UV towards the XUV frequency regime. In the bound dynamics field, the determination of multiphoton transition matrixelements has been investigated between different bound states via Rabi oscillations. (orig.)
Impact of electron–vibron interaction on the bound states in the continuum
Energy Technology Data Exchange (ETDEWEB)
Álvarez, C. [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Domínguez-Adame, F., E-mail: adame@fis.ucm.es [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Orellana, P.A. [Departamento de Física, Universidad Técnica Federico Santa María, Casilla 110 V, Valparaíso (Chile); Díaz, E. [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain)
2015-06-12
We investigate the nonequilibrium transport properties of a coupled quantum dot system connected in parallel to two leads, including electron–vibron interaction. It is known that in the absence of interaction the system supports a bound state in the continuum. This state is revealed as a Fano antiresonance in the transmission when the energy levels of the dots are detuned. Using the Keldysh nonequilibrium Green's function formalism, we find that the occurrence of the Fano antiresonance arises even if the electron–vibration interaction is taken into account. We also examine the impact of the coupling to the leads in the linear response of the system. We conclude that the existence of bound states in the continuum in coupled quantum dot systems is a robust phenomenon, opening the possibility of its observation in experiments.
Effect of bound-state dressing in laser-assisted radiative recombination
Müller, Robert A.; Seipt, Daniel; Fritzsche, Stephan; Surzhykov, Andrey
2015-11-01
We present a theoretical study on the recombination of a free electron into the ground state of a hydrogenlike ion in the presence of an external laser field. Emphasis is placed on the effects caused by the laser dressing of the residual ionic bound state. To investigate how this dressing affects the total and angle-differential cross section of laser-assisted radiative recombination (LARR) we apply first-order perturbation theory and the separable Coulomb-Volkov continuum ansatz. Using this approach, detailed calculations are performed for low-Z hydrogenlike ions and laser intensities in the range from IL=1012 to 1013W/cm2 . It is seen that the total cross section as a function of the laser intensity is remarkably affected by the bound-state dressing. Moreover, the laser dressing becomes manifest as asymmetries in the angular distribution and the (energy) spectrum of the emitted recombination photons.
Ghost-gluon and ghost-quark bound states and their role in BRST quartets
Alkofer, Natalia
2011-01-01
A non-perturbative version of the BRST quartet mechanism in infrared Landau gauge QCD is proposed for transverse gluons and quarks. Based on the positivity violation for transverse gluons the content of the respective non-perturbative BRST quartet is derived. To identify the gluon's BRST-daughter and second parent state, a truncated Bethe-Salpeter equation for the gluon-(anti-)ghost bound state is investigated. We comment shortly on several equivalent forms of this equation. Repeating the same construction for quarks leads to a truncated Bethe-Salpeter equation for a fundamentally charged quark-(anti-)ghost bound state. It turns out that a cardinal input to this equation is given by the fully dressed quark-gluon vertex, and that it is indispensable to dress the quark-gluon vertex in this equation in order to obtain a consistent truncation.
Afzal, Muhammad Imran; Lee, Yong Tak
2016-01-01
Von Neumann and Wigner theorized bounding of asymmetric eigenstates and anti-crossing of symmetric eigenstates. Experiments have shown that owing to anti-crossing and similar radiation rates, graphene-like resonance of inhomogeneously strained photonic eigenstates can generate pseudomagnetic field, bandgaps and Landau levels, while dissimilar rates induce non-Hermicity. Here, we showed experimentally higher-order supersymmetry and quantum phase transitions by resonance between similar one dimensional lattices. The lattices consisted of inhomgeneously strain-like phases of triangular solitons. The resonance created two dimensional inhomogeneously deformed photonic graphene. All parent eigenstates are annihilated. Where eigenstates of mildly strained solitons are annihilated with similar (power law) rates through one tail only and generated Hermitianally bounded eigenstates. The strongly strained solitons, positive defects are annihilated exponentially through both tails with dissimilar rates. Which bounded eig...
The double radiative annihilation of the heavy-light fermion bound states
Eeg, Jan O; Picek, I
2001-01-01
We consider the double-radiative decays of heavy-light QED and QCD atoms, $\\mu^+ e^- \\to \\gamma\\gamma$ and $\\bar{B}^{0}_s \\to \\gamma\\gamma$. Especially, we take under scrutiny contributions coming from operators that vanish on the free-quark mass shell. We show that by field redefinitions these operators are converted into contact terms attached to the bound state dynamics. A net off-shell contribution is suppressed with respect to the effect of the well known flavour-changing magnetic-moment operator by the bound-state binding factor. The negligible off-shellness of the weakly bound QED atoms becomes more relevant for strongly bound QCD atoms. We analyze this off-shellness in model-approaches to QCD, one of them enabling us to keep close contact to the related effect in QED. We also comment on the off-shell effect in the corresponding process $\\bar{B}_d \\to K^* \\gamma$, and discuss possible hindering of the claimed beyond-standard-model discovery in this decay mode.
Double pionic fusion. Towards an understanding of the ABC puzzle by exclusive measurements
Energy Technology Data Exchange (ETDEWEB)
Bashkanov, M.
2006-07-01
The ABC effect is a huge unexpected enhancement at twice the pion mass in the invariant mass spectrum of two pions, which are generated in double-pionic fusion to bound nuclear systems. This peculiar phenomenon has been missing a conclusive explanation all the time since it has been discovered 1960 in single-arm measurements of {sup 3}He ejectiles in the reaction pd{yields} {sup 3}HeX. One reason for this failure has been that all measurements to this subject have been inclusive, i.e., lacking the full experimentally accessible information. Hence exclusive measurements were performed at CELSIUS/WASA at an energy of T{sub p}=0.895 GeV, where the ABC effect is expected to be strongest. For the first time exclusive data of solid statistics for both the pd{yields}{sup 3}He{pi}{sup 0}{pi}{sup 0} and pd{yields}{sup 3}He{pi}{sup +}{pi}{sup -} reactions were obtained including also results for the three-pion production total cross-section. The new data are consistent with the previous inclusive data. They provide, however, much more additional information, which rule out all previous explications of the ABC effect. The now available kinematically complete set of data reveals that the low {pi}{pi}-mass enhancement (ABC-effect): - is not necessarily associated with a high {pi}{pi}-mass enhancement, - is always connected with the simultaneous excitation of two {delta} resonances, - is of scalar-isoscalar nature, i.e. a {sigma}-channel phenomenon, - requires dynamics in the reaction system, which has not been considered hitherto. Various possible solutions are discussed, however, all of them demand a high attraction in the {delta}{delta} system - a point, which has never been touched so far in theoretical and experimental investigations. For this data analysis new powerful methods based on neural nets have been developed. Their current and possible future applications are discussed. (orig.)
Two qubits of a W state violate Bell's inequality beyond Cirel'son's bound
Cabello, A
2002-01-01
It is shown that the correlations between two qubits selected from a trio prepared in a W state violate the Clauser-Horne-Shimony-Holt inequality more than the correlations between two qubits in any quantum state. Such a violation beyond Cirel'son's bound is smaller than the one achieved by two qubits selected from a trio in a Greenberger-Horne-Zeilinger state [A. Cabello, Phys. Rev. Lett. 88, 060403 (2002)]. However, it has the advantage that all local observers can know from their own measurements whether their qubits belongs or not to the selected pair.
A Density Matrix Renormalization Group Approach to an Asymptotically Free Model with Bound States
Martín-Delgado, M A
1999-01-01
We apply the DMRG method to the 2 dimensional delta function potential which is a simple quantum mechanical model with asymptotic freedom and formation of bound states. The system block and the environment block of the DMRG contain the low energy and high energy degrees of freedom, respectively. The ground state energy and the lowest excited states are obtained with an unprecedent accuracy. We compare the DMRG method with the Similarity RG method and propose its generalization to field theoretical models in high energy physics.
Spectrum of Andreev bound states in Josephson junctions with a ferromagnetic insulator
Energy Technology Data Exchange (ETDEWEB)
Kawabata, Shiro, E-mail: s-kawabata@aist.go.jp [Nanosystem Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); CREST, Japan Science and Technology Corporation (JST), Kawaguchi, Saitama 332-0012 (Japan); Tanaka, Yukio [Department of Applied Physics, Nagoya University, Nagoya 464-8603 (Japan); Golubov, Alexander A. [Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Vasenko, Andrey S. [Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble (France); Asano, Yasuhiro [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan)
2012-10-15
Ferromagnetic-insulator (FI) based Josephson junctions are promising candidates for a coherent superconducting quantum bit as well as a classical superconducting logic circuit. Recently the appearance of an intriguing atomic-scale 0-{pi} transition has been theoretically predicted. In order to uncover the mechanism of this phenomena, we numerically calculate the spectrum of Andreev bound states in a FI barrier by diagonalizing the Bogoliubov-de Gennes equation. We show that Andreev spectrum drastically depends on the parity of the FI-layer number L and accordingly the {pi}(0) state is always more stable than the 0 ({pi}) state if L is odd (even).
Choudhari, Tarun; Deo, Nivedita
2017-01-01
A superconductor-topological insulator-superconductor (S/TI/S) junction having normal region at angle θ is studied theoretically to investigate the junction angle dependency of the Andreev reflection and the formation of the Andreev bound states in the step and planar S/TI/S structures. It is found that the Andreev reflection becomes θ dependent only in the presence of the potential barrier at the TI/S interface. In particular, the step and planar TI/S junction have totally different conductive behavior with bias voltage and potential barrier in the regime of retro and specular Andreev reflection. Interestingly, we find that the elliptical cross section of Dirac cone, an important feature of topological insulator with step surface defect, affects the Fabry-Perot resonance of the Andreev reflection induced Andreev bound states (which become Majorana zero energy states at low chemical potential) in the step S/TI/S structure. Unlike the usual planar S/TI/S structures, we find these ellipticity affected Andreev bound states lead to non-monotonic Josephson super-current in the step S/TI/S structure whose non-monotonicity can be controlled with the use of the potential barrier, which may find applications in nanoelectronics.
Gauge invariant formulation of 3$\\gamma$ decay of particle-antiparticle bound states
Blankleider, B; Silagadze, Z K
2014-01-01
We construct the gauge invariant three-photon decay amplitude of particle-antiparticle bound states modeled by the Dyson-Schwinger and Bethe-Salpeter equations. Application to the quark-antiquark ($q\\bar{q}$) bound states is emphasized. An essential aspect of our approach is that photons are allowed to couple to the $q\\bar{q}$ system in any way allowed by the given model, i.e., not just via the dressed quark propagator as in exact QCD. In this way, applications to effective field theories and other QCD motivated models are envisioned. The three-photon decay amplitude is constructed by attaching currents to all possible places in the Feynman diagrams contributing to the dressed quark propagator. The gauge invariance of our construction is thus a direct consequence of respecting the underlying structure of the quantum field theory determining the dynamics. In the resultant expression for the three-photon decay amplitude, all the basic ingredients consisting of the bound state wave function, the final-state inte...
Vibron-polaron in alpha-helices. II. Two-vibron bound states
Falvo, C; Falvo, Cyril; Pouthier, Vincent
2005-01-01
The two-vibron dynamics associated to amide-I vibrations in a 3D $\\alpha$-helix is described according to a generalized Davydov model. The helix is modeled by three spines of hydrogen-bonded peptide units linked via covalent bonds. It is shown that the two-vibron energy spectrum supports both a two-vibron free states continuum and two kinds of bound states, called TVBS-I and TVBS-II, connected to the trapping of two vibrons onto the same amide-I mode and onto two nearest neighbor amide-I modes belonging to the same spine, respectively. At low temperature, non vanishing interspine hopping constants yield a three dimensional nature of both TVBS-I and TVBS-II which the wave functions extend over the three spines of the helix. At biological temperature, the pairs are confined in a given spine and exhibit the same features as the bound states described within a one-dimensional model. The interplay between the temperature and the 3D nature of the helix is also responsible for the occurrence of a third bound state c...
Bound-State Solution of s-Wave Klein-Gordon Equation for Woods-Saxon Potential
Directory of Open Access Journals (Sweden)
Eser Olğar
2015-01-01
Full Text Available The bound-state solution of s-wave Klein-Gordon equation is calculated for Woods-Saxon potential by using the asymptotic iteration method (AIM. The energy eigenvalues and eigenfunctions are obtained for the required condition of bound-state solutions.
The quark-gluon vertex in Landau gauge bound-state studies
Williams, Richard
2015-05-01
We present a practical method for the solution of the quark-gluon vertex for use in Bethe-Salpeter and Dyson-Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A truncation of the quark-gluon vertex, that neglects explicit back-coupling to enable the application to bound-state calculations, is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within the rainbow ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required in future bound-state calculations.
Bound-state field theory approach to proton structure effects in muonic hydrogen
Mohr, Peter J; Sapirstein, J
2013-01-01
A bound-state field theory approach to muonic hydrogen is set up using a variant of the Furry representation in which the lowest-order Hamiltonian describes a muon in the presence of a point Coulomb field, but the origin of the binding field is taken to be three charged quarks in the proton which are modeled as Dirac particles that move freely within a spherical well. Bound-state field theory techniques are used to evaluate one- and two-photon effects. Particular attention is paid to two-photon exchange diagrams, which include the effect of proton polarizability. In addition the modification of the electromagnetic self energy of the proton by the electric field of the muon is examined. Finally, the model is used to carry out a calculation of the static electric polarizability of the proton.
The quark-gluon vertex in Landau gauge bound-state studies
Energy Technology Data Exchange (ETDEWEB)
Williams, Richard [Justus-Liebig University of Giessen, Institute of Theoretical Physics, Giessen (Germany)
2015-05-15
We present a practical method for the solution of the quark-gluon vertex for use in Bethe-Salpeter and Dyson-Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A truncation of the quark-gluon vertex, that neglects explicit back-coupling to enable the application to bound-state calculations, is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within the rainbow ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required in future bound-state calculations. (orig.)
Vertical D4-D2-D0 bound states on K3 fibrations and modularity
DEFF Research Database (Denmark)
Bouchard, Vincent; Creutzig, Thomas; Diaconescu, Duiliu-Emanuel;
2016-01-01
An explicit formula is derived for the generating function of vertical D4-D2-D0 bound states on smooth K3 fibered Calabi-Yau threefolds, generalizing previous results of Gholampour and Sheshmani. It is also shown that this formula satisfies strong modularity properties, as predicted by string the...... theory. This leads to a new construction of vector valued modular forms which exhibits some of the features of a generalized Hecke transform.......An explicit formula is derived for the generating function of vertical D4-D2-D0 bound states on smooth K3 fibered Calabi-Yau threefolds, generalizing previous results of Gholampour and Sheshmani. It is also shown that this formula satisfies strong modularity properties, as predicted by string...
Baryon-baryon bound states in a (2+1)-dimensional lattice QCD model
Faria da Veiga, Paulo A.; O'Carroll, Michael; Schor, Ricardo
2003-08-01
We consider bound states of two baryons (antibaryons) in lattice QCD in a Euclidean formulation. For simplicity, we analyze an SU(3) theory with a single flavor in 2+1 dimensions and two-dimensional Dirac matrices. For a small hopping parameter 0<κ≪1 and large glueball mass, we recently showed the existence of a (anti)baryonlike particle, with an asymptotic mass of the order of -3 ln κ and with an isolated dispersion curve, i.e., an upper gap property persisting up to near the meson-baryon threshold, which is of order -5 ln κ. Here, we show that there is no baryon-baryon (or antibaryon-antibaryon) bound state solution to the Bethe-Salpeter equation up to the two-baryon threshold, which is approximately -6 ln κ.
Radiative bound-state-formation cross-sections for dark matter interacting via a Yukawa potential
Petraki, Kalliopi; de Vries, Jordy
2016-01-01
We calculate the cross-sections for the radiative formation of bound states by dark matter whose interactions are described in the non-relativistic regime by a Yukawa potential. These cross-sections are important for cosmological and phenomenological studies of dark matter with long-range interactions, residing in a hidden sector, as well as for TeV-scale WIMP dark matter. We provide the leading-order contributions to the cross-sections for the dominant capture processes occurring via emission of a vector or a scalar boson. We offer a detailed inspection of their features, including their velocity dependence within and outside the Coulomb regime, and their resonance structure. For pairs of annihilating particles, we compare bound-state formation with annihilation.
Institute of Scientific and Technical Information of China (English)
CHANG Chao-Hsi; CHEN Jiao-Kai; WANG Guo-Li
2006-01-01
We have precisely derived a "rigorous instantaneous formulation" for transitions between two bound states when the bound states are well-described by instantaneous Bethe-Salpeter (BS) equation (i.e. the kernel of the equation is instantaneous"occasionally"). The obtained rigorous instantaneous formulation, in fact, is expressed as an operator sandwiched by two "reduced BS wave functions" properly, while the reduced BS wave functions appearing in the formulation are the rigorous solutions of the instantaneous BS equation, and they may relate to Schr(o)dinger wave functions straightforwardly. We also show that the rigorous instantaneous formulation is gauge-invariant with respect to the Uem(1) transformation precisely, if the concerned transitions are radiative. Some applications of the formulation are outlined.
Differential dynamics of RAS isoforms in GDP- and GTP-bound states.
Kapoor, Abhijeet; Travesset, Alex
2015-06-01
RAS subfamily proteins regulates cell growth promoting signaling processes by cycling between active (GTP-bound) and inactive (GDP-bound) states. Different RAS isoforms, though structurally similar, exhibit functional specificity and are associated with different types of cancers and developmental disorders. Understanding the dynamical differences between the isoforms is crucial for the design of inhibitors that can selectively target a particular malfunctioning isoform. In this study, we provide a comprehensive comparison of the dynamics of all the three RAS isoforms (HRAS, KRAS, and NRAS) using extensive molecular dynamics simulations in both the GDP- (total of 3.06 μs) and GTP-bound (total of 2.4 μs) states. We observed significant differences in the dynamics of the isoforms, which rather interestingly, varied depending on the type of the nucleotide bound and the simulation temperature. Both SwitchI (Residues 25-40) and SwitchII (Residues 59-75) differ significantly in their flexibility in the three isoforms. Furthermore, Principal Component Analysis showed that there are differences in the conformational space sampled by the GTP-bound RAS isoforms. We also identified a previously unreported pocket, which opens transiently during MD simulations, and can be targeted to regulate nucleotide exchange reaction or possibly interfere with membrane localization. Further, we present the first simulation study showing GDP destabilization in the wild-type RAS protein. The destabilization of GDP/GTP occurred only in 1/50 simulations, emphasizing the need of guanine nucleotide exchange factors (GEFs) to accelerate such an extremely unfavorable process. This observation along with the other results presented in this article further support our previously hypothesized mechanism of GEF-assisted nucleotide exchange.
Lower Bounds on the Capacity of the Relay Channel with States at the Source
Directory of Open Access Journals (Sweden)
Abdellatif Zaidi
2009-01-01
Full Text Available We consider a state-dependent three-terminal full-duplex relay channel with the channel states noncausally available at only the source, that is, neither at the relay nor at the destination. This model has application to cooperation over certain wireless channels with asymmetric cognition capabilities and cognitive interference relay channels. We establish lower bounds on the channel capacity for both discrete memoryless (DM and Gaussian cases. For the DM case, the coding scheme for the lower bound uses techniques of rate-splitting at the source, decode-and-forward (DF relaying, and a Gel'fand-Pinsker-like binning scheme. In this coding scheme, the relay decodes only partially the information sent by the source. Due to the rate-splitting, this lower bound is better than the one obtained by assuming that the relay decodes all the information from the source, that is, full-DF. For the Gaussian case, we consider channel models in which each of the relay node and the destination node experiences on its link an additive Gaussian outside interference. We first focus on the case in which the links to the relay and to the destination are corrupted by the same interference; and then we focus on the case of independent interferences. We also discuss a model with correlated interferences. For each of the first two models, we establish a lower bound on the channel capacity. The coding schemes for the lower bounds use techniques of dirty paper coding or carbon copying onto dirty paper, interference reduction at the source and decode-and-forward relaying. The results reveal that, by opposition to carbon copying onto dirty paper and its root Costa's initial dirty paper coding (DPC, it may be beneficial in our setup that the informed source uses a part of its power to partially cancel the effect of the interference so that the uninformed relay benefits from this cancellation, and so the source benefits in turn.
State-Bound Estimation for Nonlinear Systems Using Randomized Mu-Analysis
2014-04-30
number of threads per block is 1024. The algorithms on the GPU is implemented using CUDA - GPU [27]. 2.3 Probabilistic Properties of the Algorithms A...between 0 and 1. As the size of the system is relatively large, the integration part is imple- mented over CUDA - GPU [27] and the programmes are shown in...delta.m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 B ErbB Signalling Pathways: GPU Example 61 B.1 state bounds for many steps main.m
Vertical D4-D2-D0 bound states on K3 fibrations and modularity
Bouchard, Vincent; Diaconescu, Duiliu-Emanuel; Doran, Charles; Quigley, Callum; Sheshmani, Artan
2016-01-01
An explicit formula is derived for the generating function of vertical D4-D2-D0 bound states on smooth K3 fibered Calabi-Yau threefolds, generalizing previous results of Gholampour and Sheshmani. It is also shown that this formula satisfies strong modularity properties, as predicted by string theory. This leads to a new construction of vector valued modular forms which exhibits some of the features of a generalized Hecke transform.
Study of -nucleus interaction through the formation of -nucleus bound state
Indian Academy of Sciences (India)
V Jha; B J Roy; A Chatterjee; H Machner
2006-05-01
The question of possible existence of -mesic nuclei is quite intriguing. Answer to this question will deeply enrich our understanding of -nucleus interaction which is not so well-understood. We review the experimental efforts for the search of -mesic nuclei and describe the physics motivation behind it. We present the description of an experiment for the search of -nucleus bound state using the GeV proton beam, currently being performed at COSY.
Dissecting zero modes and bound states on BPS vortices in Ginzburg-Landau superconductors
Alonso-Izquierdo, Alberto; Guilarte, Juan Mateos
2016-01-01
In this paper the zero modes of fluctuation of cylindrically symmetric self-dual vortices are analyzed and described in full detail. These BPS topological defects arise at the critical point between Type II and Type I superconductors, or, equivalently, when the masses of the Higgs particle and the vector boson in the Abelian Higgs model are equal. In addition, novel bound states of Higss and vector bosons trapped by the self-dual vortices at their core are found and investigated.
Phonon dilatation, dressed vibrons and two-vibron bound states localization in an adsorbed nanowire
Pouthier, Vincent,
2006-01-01
A special attention is paid to characterize the two-vibron bound state dynamics of an anharmonic molecular nanostructure coupled with a set of optical phonons. It is shown that the vibron-phonon coupling is responsible for a new dressing mechanism. The vibrons are accompanied by virtual phonons which account for the scaling of each phonon coordinate and for the dilatation of the corresponding wave function. As a result, the dynamics of the dressed vibrons is governed by an effective Hamiltoni...
Vertical D4-D2-D0 bound states on K3 fibrations and modularity
DEFF Research Database (Denmark)
Bouchard, Vincent; Creutzig, Thomas; Diaconescu, Duiliu-Emanuel;
2016-01-01
An explicit formula is derived for the generating function of vertical D4-D2-D0 bound states on smooth K3 fibered Calabi-Yau threefolds, generalizing previous results of Gholampour and Sheshmani. It is also shown that this formula satisfies strong modularity properties, as predicted by string...... theory. This leads to a new construction of vector valued modular forms which exhibits some of the features of a generalized Hecke transform....
Vertical D4-D2-D0 Bound States on K3 Fibrations and Modularity
Bouchard, Vincent; Creutzig, Thomas; Diaconescu, Duiliu-Emanuel; Doran, Charles; Quigley, Callum; Sheshmani, Artan
2017-03-01
An explicit formula is derived for the generating function of vertical D4-D2-D0 bound states on smooth K3 fibered Calabi-Yau threefolds, generalizing previous results of Gholampour and Sheshmani. It is also shown that this formula satisfies strong modularity properties, as predicted by string theory. This leads to a new construction of vector valued modular forms which exhibit some of the features of a generalized Hecke transform.
F(750), We Miss You, as Bound State of 6 Top and 6 Anti top
Nielsen, Holger Frits Bech
2016-01-01
We collect and estimate support for our long speculated "multiple point principle" saying that there should be several vacua all having (compared to the scales of high energy physics) very low energy densities. In pure Standard Model we suggest there being three by "multiple point principle" low energy density vacua, "present", "condensate" and "high field" vacuum. We fit the mass of the in our picture since long speculated bound state of six top and six anti top quarks in three quite {\\em independent ways} and get remarkably within our crude accuracy the {\\em same} mass in all three fits! The new point of the present article is to estimate the bound state mass in what we could call a bag model estimation. The two other fits, which we review, obtain the mass of the bound state by fitting to the multiple point principle prediction of degenerate vacua. Our remarkable agreement of our three mass-fits can be interpreted to mean, that we have calculated at the end the energy densities of the two extra speculated v...
Quantization of the Closed Mini-Superspace Models as Bound States
Kung, J H
1995-01-01
Wheeler-DeWitt equation is applied to $k > 0$ Friedmann Robertson Walker metric with various types of matter. It is shown that if the Universe ends in the matter dominated era (e.g., radiation or pressureless gas) with zero cosmological constant, then the resulting Wheeler-DeWitt equation describes a bound state problem. As solutions of a non-degenerate bound state system, the eigen-wave functions are real (Hartle-Hawking) and the usual issue associated with the ambiguity in the boundary conditions for the wave functions is resolved. Furthermore, as a bound state problem, there exists a quantization condition that relates the curvature of the three space with the energy density of the Universe. Incorporating a cosmological constant in the early Universe (inflation) is given as a natural explanation for the large quantum number associated with our Universe, which resulted from the quantization condition. It is also shown that if there is a cosmological constant $\\Lambda > 0$ in our Universe that persists for a...
Gluon bound state and asymptotic freedom derived from the Bethe--Salpeter equation
Fukamachi, Hitoshi; Nishino, Shogo; Shinohara, Toru
2016-01-01
In this paper we study the two-body bound states for gluons and ghosts in a massive Yang-Mills theory which is obtained by generalizing the ordinary massless Yang-Mills theory in a manifestly Lorentz covariant gauge. First, we give a systematic derivation of the coupled Bethe-Salpeter equations for gluons and ghosts by using the Cornwall-Jackiw-Tomboulis effective action of the composite operators within the framework of the path integral quantization. Then, we obtain the numerical solutions for the Bethe-Salpeter amplitude representing the simultaneous bound states of gluons and ghosts by solving the homogeneous Bethe-Salpeter equation in the ladder approximation. We study how the inclusion of ghosts affects the two-gluon bound states in the cases of the standing and running gauge coupling constant. Moreover, we show explicitly that the approximate solutions obtained for the gluon-gluon amplitude are consistent with the ultraviolet asymptotic freedom signaled by the negative $\\beta$ function.
Meson-baryon bound states in a (2+1)-dimensional strongly coupled lattice QCD model
Neto, Antônio Francisco
2004-08-01
We consider bound states of a meson and a baryon (meson and antibaryon) in lattice QCD in a Euclidean formulation. For simplicity, considering the + parity sector we analyze an SU(3) theory with a single flavor in 2+1 dimensions and two-dimensional Dirac matrices. We work in the strong coupling regime, i.e., in a region of parameters such that the hopping parameter κ is sufficiently small and κ≫g-20, where g-20 is the pure gauge coupling. There is a meson (baryon) particle with asymptotic mass -2 ln κ (-3 ln κ) and an isolated dispersion curve. Here, in a ladder approximation, we show that there is no meson baryon (or meson-antibaryon) bound state solution to the Bethe-Salpeter equation up to the meson-baryon threshold (˜-5 ln κ). The absence of such a bound state is an effect of a spatial range-one repulsive potential that is local in space at order κ3, i.e., the leading order in the hopping parameter κ.
Meson-meson bound states in a (2+1)-dimensional strongly coupled lattice QCD model
Faria da Veiga, Paulo A.; O'Carroll, Michael; Neto, Antônio Francisco
2004-05-01
We consider bound states of two mesons (antimesons) in lattice quantum chromodynamics in an Euclidean formulation. For simplicity, we analyze an SU(3) theory with a single flavor in 2+1 dimensions and two-dimensional Dirac matrices. For a small hopping parameter κ and small plaquette coupling g-20, such that 0
Conformation-Selective Resonant Photoelectron Spectroscopy via Dipole-Bound States of Cold Anions.
Huang, Dao-Ling; Liu, Hong-Tao; Ning, Chuan-Gang; Wang, Lai-Sheng
2015-06-18
Molecular conformation is important in chemistry and biochemistry. Conformers connected by low energy barriers can only be observed at low temperatures and are difficult to be separated. Here we report a new method to obtain conformation-selective spectroscopic information about dipolar molecular radicals via dipole-bound excited states of the corresponding anions cooled in a cryogenic ion trap. We observed two conformers of cold 3-hydroxyphenoxide anions [m-HO(C6H4)O(-)] in high-resolution photoelectron spectroscopy and measured different electron affinities, 18,850(8) and 18,917(5) cm(-1), for the syn and anti 3-hydroxyphenoxy radicals, respectively. We also observed dipole-bound excited states for m-HO(C6H4)O(-) with different binding energies for the two conformers due to the different dipole moments of the corresponding 3-hydroxyphenoxy radicals. Excitations to selected vibrational levels of the dipole-bound states result in conformation-selective photoelectron spectra. This method should be applicable to conformation-selective spectroscopic studies of any anions with dipolar neutral cores.
Fox, Zachary; Neuert, Gregor; Munsky, Brian
2016-08-01
Emerging techniques now allow for precise quantification of distributions of biological molecules in single cells. These rapidly advancing experimental methods have created a need for more rigorous and efficient modeling tools. Here, we derive new bounds on the likelihood that observations of single-cell, single-molecule responses come from a discrete stochastic model, posed in the form of the chemical master equation. These strict upper and lower bounds are based on a finite state projection approach, and they converge monotonically to the exact likelihood value. These bounds allow one to discriminate rigorously between models and with a minimum level of computational effort. In practice, these bounds can be incorporated into stochastic model identification and parameter inference routines, which improve the accuracy and efficiency of endeavors to analyze and predict single-cell behavior. We demonstrate the applicability of our approach using simulated data for three example models as well as for experimental measurements of a time-varying stochastic transcriptional response in yeast.
Upper bound for SL-invariant entanglement measures of mixed states
Osterloh, Andreas
2016-05-01
An algorithm is proposed that serves to handle full-rank density matrices when coming from a lower-rank method to compute the convex roof. This is in order to calculate an upper bound for any polynomial SL-invariant multipartite entanglement measure E . This study exemplifies how this algorithm works based on a method for calculating convex roofs of rank-2 density matrices. It iteratively considers the decompositions of the density matrix into two states each, exploiting the knowledge for the rank-2 case. The algorithm is therefore quasiexact as far as the rank-2 case is concerned, and it also hints where it should include more states in the decomposition of the density matrix. Focusing on the measure of three-way entanglement of qubits (called three-tangle), I show the results the algorithm gives for two states, one of which is the Greenberger-Horne-Zeilinger-Werner (GHZ-W ) state, for which the exact convex roof is known. It overestimates the three-tangle in the state, thereby giving insight into the optimal decomposition the GHZ-W state has. As a proof of principle, I have run the algorithm for the three-tangle on the transverse quantum Ising model. I give qualitative and quantitative arguments why the convex roof should be close to the upper bound found here.
Afzal, Muhammad Imran; Lee, Yong Tak
2016-12-01
Von Neumann and Wigner theorized the bounding and anti-crossing of eigenstates. Experiments have demonstrated that owing to anti-crossing and similar radiation rates, the graphene-like resonance of inhomogeneously strained photonic eigenstates can generate a pseudomagnetic field, bandgaps and Landau levels, whereas exponential or dissimilar rates induce non-Hermicity. Here, we experimentally demonstrate higher-order supersymmetry and quantum phase transitions by resonance between similar one-dimensional lattices. The lattices consisted of inhomogeneous strain-like phases of triangular solitons. The resonance created two-dimensional, inhomogeneously deformed photonic graphene. All parent eigenstates were annihilated. Eigenstates of mildly strained solitons were annihilated at similar rates through one tail and generated Hermitian bounded eigenstates. The strongly strained solitons with positive phase defects were annihilated at exponential rates through one tail, which bounded eigenstates through non-Hermitianally generated exceptional points. Supersymmetry was evident, with preservation of the shapes and relative phase differences of the parent solitons. Localizations of energies generated from annihilations of mildly and strongly strained soliton eigenstates were responsible for geometrical (Berry) and topological phase transitions, respectively. Both contributed to generating a quantum Zeno phase, whereas only strong twists generated topological (Anderson) localization. Anti-bunching-like condensation was also observed.
Why bound-state calculations of tetraquarks should be met with scepticism
Rupp, George
2016-01-01
Recent experimental signals have led to a revival of tetraquarks, the hypothetical $q^2\\bar{q}^2$ hadronic states proposed by Jaffe in 1976 to explain the light scalar mesons. Mesonic structures with exotic quantum numbers have indeed been observed recently, though a controversy persists whether these are true resonances and not merely kinematical threshold enhancements, or otherwise states not of a true $q^2\\bar{q}^2$ nature. Moreover, puzzling non-exotic mesons are also often claimed to have a tetraquark configuration. However, the corresponding model calculations are practically always carried out in pure bound-state approaches, ignoring completely the coupling to asymptotic two-meson states and unitarity, especially the dynamical effects thereof. In this short paper we argue that such static predictions of real tetraquark masses are highly unreliable and provide little evidence of the very existence of such states.
Decay of Bethe-Salpeter kernel and bound states for the lattice four Fermi model
Energy Technology Data Exchange (ETDEWEB)
Anjos, Petrus Henrique Ribeiro dos [Universidade Federal de Goias (UFG), Goiania, GO (Brazil)
2012-07-01
Full text: We consider an imaginary-time functional integral formulation of the the lattice four-Fermi or Gross-Neveu model in d + 1 space-time dimensions (d = 1, 2, 3) and with N-component fermions. Let 0 < {kappa} << 1 be the hopping parameter, {lambda} > 0 the four-fermion coupling, m > 0 the bare fermion mass and take s x s spin matrices (s = 2,4). In a previous work, we derive spectral representations for two- and four- point correlation functions and use this result to show that the low-lying energy-momentum spectrum of this model exhibits isolated dispersion curves which are identified as single particles, multi-particle bands and bound states. In this previous analysis, the one-particle energy-momentum spectrum is obtained rigorously and is manifested by sN/2 isolated and identical dispersion curves, and the mass of particles has asymptotic value order of order 1n {kappa}. The existence of two-particle bound states above or below the two-particle band depends on whether Gaussian domination does hold or does not, respectively. Two-particle bound states emerge from solutions to a lattice Bethe-Salpeter equation that we solve in a ladder approximation. Within this approximation, the bound states have O({kappa}{sup 0}) binding energies at zero system momentum and their masses are all equal, with value {approx} -2 1n {kappa}. In this work, using the hyperplane decoupling method, we provide a detailed analysis of the decay of the Bethe-Salpeter kernel and show how to use this decay to extend the spectral result obtained in the ladder approximation to the full model. In particular, we prove that if the two-point function decays faster than the four-point function (Gaussian subjugation) then the only point in the mass spectrum above the one-particle mass and below the two-particle band is the bound state mass. (author)
Bound states in a model of interaction of Dirac field with material plane
Directory of Open Access Journals (Sweden)
Pismak Yu. M.
2016-01-01
Full Text Available In the framework of the Symanzik approach model of the interaction of the Dirac spinor field with the material plane in the 3 + 1-dimensional space is constructed. The model contains eight real parameters characterizing the properties of the material plane. The general solution of the Euler-Lagrange equations of the model and dispersion equations for bound states are analyzed. It is shown that there is a choice of parameters of the model in which the connected states are characterized by dispersion law of a mass-less particle moving along the material plane with the dimensionless Fermi velocity not exceeding one.
Variational approach to bound states in scalar-gluon field theory
Energy Technology Data Exchange (ETDEWEB)
Dietz, K.; Romer, H.
1976-10-15
Two variational approaches are employed to attack the bound-state problem of a charged scalar field interacting with an Abelian gauge field. The resulting variational equations allow for a qualitative discussion of all possible physical situations. Boundary conditions play a crucial role in their interpretation. A specially developed perturbation scheme yields hydrogenlike spectra. ''Self-trapping'' solutions and configurations with complete screening of the long-range force are discussed and are shown not to be obtainable by perturbation for small coupling. Metastable states appear for strong coupling. (AIP)
Formation Mechanism of Guided Resonances and Bound States in the Continuum in Photonic Crystal Slabs
Gao, Xingwei; Zhen, Bo; Lin, Xiao; Joannopoulos, John D; Soljačić, Marin; Chen, Hongsheng
2016-01-01
We develop a formalism, based on the mode expansion method, to describe the guided resonances and bound states in the continuum (BICs) in photonic crystal slabs with one-dimensional periodicity. This approach provides analytic insights to the formation mechanisms of these states: the guided resonances arise from the transverse Fabry-P\\'erot condition, and the divergence of the resonance lifetimes at the BICs is explained by a destructive interference of radiation from different propagating components inside the slab. We show BICs at the center and on the edge of the Brillouin zone protected by symmetry, as well as BICs at generic wave vectors not protected by symmetry.
NN S-Wave Elastic Cross Section and Possible Bound States in a Constituent Quark Model
Institute of Scientific and Technical Information of China (English)
PANG Hou-Rong; PING Jia-Lun; WANG Fan
2008-01-01
In the framework of a chiral constituent quark model, considering the contributions of π annihilation and one-gluon annihilation, the proton-antiproton s-wave elastic scattering cross section experimental data can be reproduced by adjusting properly one-gluon annihilation coupling constant. After fixing the model parameters, we perform a dynamical calculation for all possible s-wave nucleon-antinucleon states. The results show that there is no s-wave bound state as indicated by a strong enhancement at threshold of pp in J/ψ and B decay.
Evidence for a Possible Proton-Antiproton Bound State from Lattice QCD
Loan, M
2006-01-01
We have used standard techniques of lattice quantum chromodynamics to look for evidence of the spin-zero six quark flavour singlet state ($J^{PC}=0^{-+}$) observed by BES Collaboration, and to determine the splitting between the mass of the possible proton-antiproton and the mass of two protons, its threshold. Ignoring quark loops and quark annihilation, we find indications that for sufficiently light quarks proton- antiproton is below the $2m_{p}$ threshold, making it a possible six-quark bound state.
Search for d* dibaryon by double-radiative capture on pionic deuterium
Energy Technology Data Exchange (ETDEWEB)
Zolnierczuk, P.A.; Gorringe, T.P.; Hasinoff, M.D.; Kovash, M.A.; Tripathi, S.; Wright, D.H
2002-12-05
We report a search for d* dibaryon production by double-radiative capture on pionic deuterium. The experiment was conducted at the TRIUMF cyclotron using the RMC cylindrical pair spectrometer, and detected {gamma}-ray coincidences following pion stops in liquid deuterium. We found no evidence for narrow dibaryons, and obtained a branching ratio upper limit, BR<6.7x10{sup -6} (90% C.L.), for narrow d* production in the mass range from 1920 to 1980 MeV.
Search for d^* Dibaryon by Double-radiative Capture on Pionic Deuterium
Zolnierczuk, P A; Hasinoff, M D; Kovash, M A; Tripathi, S; Wright, D H
2002-01-01
We report a search for d^* dibaryon production by double-radiative capture on pionic deuterium. The experiment was conducted at the TRIUMF cyclotron using the RMC cylindrical pair spectrometer, and detected gamma-ray coincidences following pion stops in liquid deuterium. We found no evidence for narrow dibaryons, and obtained a branching ratio upper limit, BR < 1.5 times 10^{-6} (90% C.L.), for narrow d^* production in the mass range from 1920 to 1980 MeV.
Bounded-Error Quantum State Identification and Exponential Separations in Communication Complexity
Gavinsky, D; Kempe, J; Regev, O; Gavinsky, Dmitry; Kempe, Julia; Regev, Oded; Wolf, Ronald de
2005-01-01
We consider the problem of bounded-error quantum state identification: given either state \\alpha_0 or state \\alpha_1, we are required to output `0', `1' or `?' ("don't know"), such that conditioned on outputting `0' or `1', our guess is correct with high probability. The goal is to maximize the probability of not outputting `?'. We prove a direct product theorem: if we're given two such problems, with optimal probabilities a and b, respectively, and the states in the first problem are pure, then the optimal probability for the joint bounded-error state identification problem is O(ab). Our proof is based on semidefinite programming duality and may be of wider interest. Using this result, we present two exponential separations in the simultaneous message passing model of communication complexity. Both are shown in the strongest possible sense. First, we describe a relation that can be computed with O(log n) classical bits of communication in the presence of shared randomness, but needs Omega(n^{1/3}) communicat...
Bound states and Cooper pairs of molecules in 2D optical lattices bilayer
Energy Technology Data Exchange (ETDEWEB)
Camacho-Guardian, A.; Dominguez-Castro, G.A.; Paredes, R. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico)
2016-08-15
We investigate the formation of Cooper pairs, bound dimers and the dimer-dimer elastic scattering of ultracold dipolar Fermi molecules confined in a 2D optical lattice bilayer configuration. While the energy and their associated bound states are determined in a variational way, the correlated two-molecule pair is addressed as in the original Cooper formulation. We demonstrate that the 2D lattice confinement favors the formation of zero center mass momentum bound states. Regarding the Cooper pairs binding energy, this depends on the molecule populations in each layer. Maximum binding energies occur for non-zero (zero) pair momentum when the Fermi system is polarized (unpolarized). We find an analytic expression for the dimer-dimer effective interaction in the deep BEC regime. The present analysis represents a route for addressing the BCS-BEC crossover in dipolar Fermi gases confined in 2D optical lattices within the current experimental panorama. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Bound States of the q-Deformed AdS5 x S5 Superstring S-matrix
Hoare, Ben; Miramontes, J Luis
2012-01-01
The investigation of the q deformation of the S-matrix for excitations on the string world sheet in AdS5 x S5 is continued. We argue that due to the lack of Lorentz invariance the situation is more subtle than in a relativistic theory in that the nature of bound states depends on their momentum. At low enough momentum |p|1. This subtlety fixes a problem involving the consistency of crossing symmetry with the relativistic limit found in earlier work. With mirror kinematics, obtained after a double Wick rotation, the bound state structure is simpler and there are no marginally unstable bound states.
Full-potential multiple scattering theory with space-filling cells for bound and continuum states.
Hatada, Keisuke; Hayakawa, Kuniko; Benfatto, Maurizio; Natoli, Calogero R
2010-05-12
We present a rigorous derivation of a real-space full-potential multiple scattering theory (FP-MST) that is free from the drawbacks that up to now have impaired its development (in particular the need to expand cell shape functions in spherical harmonics and rectangular matrices), valid both for continuum and bound states, under conditions for space partitioning that are not excessively restrictive and easily implemented. In this connection we give a new scheme to generate local basis functions for the truncated potential cells that is simple, fast, efficient, valid for any shape of the cell and reduces to the minimum the number of spherical harmonics in the expansion of the scattering wavefunction. The method also avoids the need for saturating 'internal sums' due to the re-expansion of the spherical Hankel functions around another point in space (usually another cell center). Thus this approach provides a straightforward extension of MST in the muffin-tin (MT) approximation, with only one truncation parameter given by the classical relation l(max) = kR(b), where k is the electron wavevector (either in the excited or ground state of the system under consideration) and R(b) is the radius of the bounding sphere of the scattering cell. Moreover, the scattering path operator of the theory can be found in terms of an absolutely convergent procedure in the l(max) --> ∞ limit. Consequently, this feature provides a firm ground for the use of FP-MST as a viable method for electronic structure calculations and makes possible the computation of x-ray spectroscopies, notably photo-electron diffraction, absorption and anomalous scattering among others, with the ease and versatility of the corresponding MT theory. Some numerical applications of the theory are presented, both for continuum and bound states.
Rivera, Nicholas; Hsu, Chia Wei; Zhen, Bo; Buljan, Hrvoje; Joannopoulos, John D.; Soljačić, Marin
2016-09-01
A bound state in the continuum (BIC) is an unusual localized state that is embedded in a continuum of extended states. Here, we present the general condition for BICs to arise from wave equation separability. Then we show that by exploiting perturbations of certain symmetry such BICs can be turned into resonances that radiate with a tailorable directionality and dimensionality. Using this general framework, we construct new examples of separable BICs and resonances that can exist in optical potentials for ultracold atoms, photonic systems, and systems described by tight binding. Such resonances with easily reconfigurable radiation allow for applications such as the storage and release of waves at a controllable rate and direction, as well systems that switch between different dimensions of confinement.
Khan, Md Abdul
2015-01-01
Bound state properties of few single and double-$\\Lambda$ hypernuclei is critically examined in the framework of core-$\\Lambda$ and core+$\\Lambda+\\Lambda$ few-body model applying hyperspherical harmonics expansion method (HHEM). The $\\Lambda\\Lambda$ potential is chosen phenomenologically while the core-$\\Lambda$ potential is obtained by folding a phenomenological $\\Lambda N$ interaction into the density distribution of the core. The depth of the effective $\\Lambda N$ potential is adjusted to reproduce the experimental data for the core-$\\Lambda$ subsystem. The three-body Schr\\"odinger equation is solved by hyperspherical adiabatic approximation (HAA) to get the ground state energy and wave function. The ground state wavefunction is used to construct the supersymmetric partner potential following prescription of supersymmetric quantum mechanics (SSQM) algebra. The newly constructed supersymmetric partner potential is used to solve the three-body Schr\\"odinger equation to get the energy and wavefunction for the...
Three-body bound states in dipole-dipole interacting Rydberg atoms
Kiffner, Martin; Jaksch, Dieter
2013-01-01
We show that the dipole-dipole interaction between three identical Rydberg atoms can give rise to bound trimer states. The microscopic origin of these states is fundamentally different from Efimov physics. Two stable trimer configurations exist where the atoms form the vertices of an equilateral triangle in a plane perpendicular to a static electric field. The triangle edge length typically exceeds $R\\approx 2\\,\\mu\\text{m}$, and each configuration is two-fold degenerate due to Kramers' degeneracy. The depth of the potential wells and the triangle edge length can be controlled by external parameters. We establish the Borromean nature of the trimer states, analyze the quantum dynamics in the potential wells and describe methods for their production and detection.
Studies on bound-state spectra of Manning-Rosen potential
Roy, Amlan K
2014-01-01
Accurate ro-vibrational energies, eigenfunctions, radial densities, expectation values are presented for the exponential-type Manning-Rosen (MR) potential. Bound states accurate up to ten significant figure are obtained by employing a simple, reliable generalized pseudospectral method. \\emph{All} 55 eigenstates with $n \\leq 10$ are treated for arbitrary values of potential parameters, covering a wide range of interaction, through a \\emph{non-uniform, optimal} spatial radial discretization. A detailed investigation has been made on energy changes with respect to \\emph{screening and other} potential parameters. A systematic estimation of \\emph{critical} screening parameters are given for these eigenstates. Special emphasis has been given to \\emph{higher} states and in the vicinity of \\emph{critical screening} region. A thorough comparison with literature results is made wherever possible. This \\emph{surpasses} the accuracy of \\emph{all} other existing methods currently available. Several \\emph{new} states are r...
Quantum Zeno and anti-Zeno effects in an unstable system with two bound states
Energy Technology Data Exchange (ETDEWEB)
Modi, Kavan [Department of Physics, Center for Complex Quantum Systems, University of Texas at Austin, Austin, TX 78712-1081 (United States)], E-mail: modik@physics.utexas.edu; Shaji, Anil [Department of Physics, Center for Complex Quantum Systems, University of Texas at Austin, Austin, TX 78712-1081 (United States)
2007-08-20
We analyze the experimental observations reported by Fischer et al. [M.C. Fischer, B. Gutierrez-Medina, M.G. Raizen, Phys. Rev. Lett. 87 (2001) 040402] by considering a system of coupled unstable bound quantum states |A> and |B>. The state |B> is coupled to a set of continuum states |C{theta}({omega})>. We investigate the time evolution of |A> when it decays into |C{theta}({omega})> via |B>, and find that frequent measurements on |A> leads to both the quantum Zeno effect and the anti-Zeno effects depending on the frequency of measurements. We show that it is the presence of |B> which allows for the anti-Zeno effect.
In-medium ηN interactions and η nuclear bound states
Cieplý, A.; Friedman, E.; Gal, A.; Mareš, J.
2014-05-01
The in-medium ηN interaction near and below threshold is constructed from a free-space chirally-inspired meson-baryon coupled-channel model that captures the physics of the N*(1535) baryon resonance. Nucleon Pauli blocking and hadron self-energies are accounted for. The resulting energy-dependent in-medium interaction is used in self-consistent dynamical calculations of η nuclear bound states. Narrow states of width Γη≲2 MeV are found across the periodic table, beginning with A⩾10, for this in-medium coupled-channel interaction model. The binding energy of the 1sη state increases with A, reaching a value of B1s(η)≈15 MeV. The implications of our self-consistency procedure are discussed with respect to procedures used in other works.
The effect of bound state dressing in laser assisted radiative recombination
Müller, Robert Alexander; Fritzsche, Stephan; Surzhykov, Andrey
2015-01-01
We present a theoretical study on the recombination of a free electron into the ground state of a hydrogen-like ion in the presence of an external laser field. Emphasis is placed on the effects caused by the laser dressing of the residual ionic bound state. To investigate how this dressing affects the total and angle-differential cross section of laser assisted radiative recombination (LARR) we apply first-order perturbation theory and the separable Coulomb-Volkov-continuum ansatz. Using this approach detailed calculations were performed for low-$Z$ hydrogen like ions and laser intensities in the range from $I_L=10^{11}\\text{W/cm}^2$ to $I_L=10^{13}\\text{W/cm}^2$. It is seen that the total cross section as a function of the laser intensity is remarkably affected by the bound state dressing. Moreover the laser dressing becomes manifest as asymmetries in the angular distribution and the (energy) spectrum of the emitted recombination photons.
Spinon and bound-state excitation light cones in Heisenberg XXZ chains
de Paula, A. L.; Bragança, H.; Pereira, R. G.; Drumond, R. C.; Aguiar, M. C. O.
2017-01-01
We investigate the out-of-equilibrium dynamics after a local quench that connects two spin-1/2 XXZ chains prepared in the ground state of the Hamiltonian in different phases, one in the ferromagnetic phase and the other in the critical phase. We analyze the time evolution of the on-site magnetization and bipartite entanglement entropy via adaptive time-dependent density matrix renormalization group. In systems with short-range interactions, such as the one we consider, the velocity of information transfer is expected to be bounded, giving rise to a light-cone effect. Interestingly, our results show that, when the anisotropy parameter of the critical chain is sufficiently close to that of the isotropic ferromagnet, the light cone is determined by the velocity of spin-wave bound states that propagate faster than single-particle ("spinon") excitations. Furthermore, we investigate how the system approaches equilibrium in the inhomogeneous ground state of the connected system, in which the ferromagnetic chain induces a nonzero magnetization in the critical chain in the vicinity of the interface.
Search for the eta-mesic Helium bound state with the WASA-at-COSY facility
Skurzok, M; Rundel, O; Moskal, P
2015-01-01
We performed a search for 4He-eta bound state with high statistics and high acceptance with the WASA-at-COSY facility using a ramped beam technique. The signature of eta-mesic nuclei is searched for in dd -> 3Henpi0 and dd -> 3Heppi- reactions by the measurement of the excitation functions in the vicinity of the {\\eta} production threshold. This paper presents the experimental method and the preliminary results of the data analysis for dd -> 3Henpi0 process.
Cygnus X-3: A source of highly symmetric quark bound states. [Cyg X-3
Energy Technology Data Exchange (ETDEWEB)
Horvath, J.E.; Benvenuto, O.G. (Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 49 y 115, Casilla de Correo 67, 1900 La Plata (Argentina) Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata (Argentina))
1990-06-01
The point source Cygnus X-3 continues to show puzzling features related to underground modulated muon signals and also an excess of hadron groups recently reported. We propose that the neutral particle responsible for these unusual facts could be a highly symmetric bound QCD state (quark-alpha) recently hypothesized. Interactions of these primaries with ordinary matter and astrophysical expectations are addressed and it is concluded that this proposal is in principle capable of providing some desirable ingredients for an explanation of the data.
Applying the relativistic quantization condition to a three-particle bound state in a periodic box
Hansen, Maxwell T.; Sharpe, Stephen R.
2017-02-01
Using our recently developed relativistic three-particle quantization condition [Phys. Rev. D 90, 116003 (2014), 10.1103/PhysRevD.90.116003; Phys. Rev. D 92, 114509 (2015), 10.1103/PhysRevD.92.114509], we study the finite-volume energy shift of a spin-zero three-particle bound state. We reproduce the result obtained using nonrelativistic quantum mechanics by Meißner et al. in [Phys. Rev. Lett. 114, 091602 (2015), 10.1103/PhysRevLett.114.091602] and generalize the result to a moving frame.
A search for deeply-bound kaonic nuclear states at J-PARC
Directory of Open Access Journals (Sweden)
Sakaguchi A.
2010-04-01
Full Text Available The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, K− pp, by the in-ﬂight 3He(K−,n reaction. The exclusive measurement can be performed by a simultaneous measurement of the missing mass using the primary neutron and the invariant mass via the expected decay, K− pp → Λp → pπ− p. In this report, an overview of the experiment and the preparation status are presented.
Formation of bound states of electrons in spherically symmetric oscillations of plasma
Dvornikov, Maxim
2010-01-01
We study spherically symmetric oscillations of electrons in plasma in frames of the classical electrodynamics. First we analyze the electromagnetic potentials for the system of radially oscillating charged particles. Then we consider both free and forced spherically symmetric oscillations of electrons. Finally we discuss the interaction between radially oscillating electrons through the exchange of ion acoustic waves. It is obtained that the effective potential of this interaction can be attractive and can transcend the Debye-Hueckel potential. We suggest that oscillating electrons can form bound states at the initial staged of the spherical plasma structure evolution. The application of the obtained results to the theory of natural plasmoids are considered.
Electron-electron bound states in parity-preserving QED{sub 3}
Energy Technology Data Exchange (ETDEWEB)
Belich, H.; Helayel-Neto, J.A. [Universidade Catolica do Petropolis, RJ (Brazil). Grupo de Fisica Teorica]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas; Cima, O.M. del [Universidade Catolica do Petropolis, RJ (Brazil). Grupo de Fisica Teorica; Ferreira Junior, M.M. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]|[Maranhao Univ., Sao Luis, MA (Brazil). Dept. de Fisica
2002-04-01
By considering the Higgs mechanism in the framework of a parity-preserving Planar Quantum Electrodynamics, one shows that an attractive electron-electron interaction may dominate. The e{sup -}e{sup -} interaction potential emerges as the non-relativistic limit of the Moeller scattering amplitude and it results attractive with a suitable choice of parameters. Numerically values of the e{sup -}e{sup -} binding energy are obtained by solving the two-dimensional Schroedinger equation. The existence of bound states is a strong indicative that this model may be adopted to address the pairing mechanism of high-T{sub c} superconductivity. (author)
The beauty of impurities: Two revivals of Friedel's virtual bound-state concept
Georges, Antoine
2016-03-01
Jacques Friedel pioneered the theoretical study of impurities and magnetic impurities in metals. He discovered Friedel oscillations, introduced the concept of virtual bound-state, and demonstrated that the charge on the impurity is related to the scattering phase-shift at the Fermi level (Friedel sum-rule). After a brief review of some of these concepts, I describe how they proved useful in two new contexts. The first one concerns the Coulomb blockade in quantum dots, and its suppression by the Kondo effect. The second one is the dynamical mean-field theory of strong electronic correlations. xml:lang="fr"
K− absorption on two nucleons and ppK− bound state search in the Σ0p final state
Directory of Open Access Journals (Sweden)
O. Vázquez Doce
2016-07-01
Full Text Available We report the measurement of K− absorption processes in the Σ0p final state and the first exclusive measurement of the two nucleon absorption (2NA with the KLOE detector. The 2NA process without further interactions is found to be 9% of the sum of all other contributing processes, including absorption on three and more nucleons or 2NA followed by final state interactions with the residual nucleons. We also determine the possible contribution of the ppK− bound state to the Σ0p final state. The yield of ppK−/Kstop− is found to be (0.044±0.009stat−0.005+0.004syst⋅10−2 but its statistical significance based on an F-test is only 1σ.
Effect of the Velocity-Dependent Potentials on the Bound State Energy Eigenvalues
Institute of Scientific and Technical Information of China (English)
O.Bayrak; A.Soylu; I.Boztosun
2011-01-01
We investigate the effect of isotropic velocity-dependent potentials on the bound state energy eigenvalues for the first time for any quantum states of the Coulomb and harmonic oscillator potentials within the framework of the asymptotic iteration method. When the velocity-dependent term is selected as a constant parameter po, we present that the energy eigenvalues can be obtained analytically for both Coulomb and harmonic oscillator potentials. However, when the velocity-dependent term is considered as a harmonic oscillator type poΥ2, taking the velocity-dependent term as a perturbation, we present how to obtain the energy eigenvalues of the Coulomb and harmonic oscillator potentials for any n and (e) quantum states by using perturbation expansion and numerical calculations in the asymptotic iteration method procedure.%@@ We investigate the effect of isotropic velocity-dependent potentials on the bound state energy eigenvalues for the first time for any quantum states of the Coulomb and harmonic oscillator potentials within the framework of the asymptotic iteration method.When the velocity-dependent term is selected as a constant parameter po,we present that the energy eigenvalues can be obtained analytically for both Coulomb and harmonic oscillator potentials.However, when the velocity-dependent term is considered as a harmonic oscillator type por2, taking the velocity-dependent term as a perturbation, we present how to obtain the energy eigenvalues of the Coulomb and harmonic oscillator potentials for any n and e quantum states by using perturbation expansion and numerical calculations in the asymptotic iteration method procedure.
Relativistic two-body bound states in scalar QFT: variational basis-state approach
Energy Technology Data Exchange (ETDEWEB)
Emami-Razavi, Mohsen [Centre for Research in Earth and Space Science, York University, Toronto, Ontario, M3J 1P3 (Canada); Darewych, Jurij W [Department of Physics and Astronomy, York University, Toronto, Ontario, M3J 1P3 (Canada)
2006-08-15
We use the Hamiltonian formalism of quantum field theory and the variational basis-state method to derive relativistic coupled-state wave equations for scalar particles interacting via a massive or massless mediating scalar field (the scalar Yukawa model). A variational trial state comprised of two and four Fock-space states is used to derive coupled wave equations for a relativistic two (and four) body system. Approximate, variational two-body ground-state solutions of the relativistic equations are obtained for various strengths of coupling, for both massive and massless mediating fields. The results show that the inclusion of virtual pairs has a large effect on the two-body binding energy at strong coupling. A comparison of the two-body binding energies with other calculations is presented.
Hsieh, Timothy H; Fu, Liang
2012-03-09
The recently discovered superconductor Cu(x)Bi2Se3 is a candidate for three-dimensional time-reversal-invariant topological superconductors, which are predicted to have robust surface Andreev bound states hosting massless Majorana fermions. In this work, we analytically and numerically find the linearly dispersing Majorana fermions at k=0, which smoothly evolve into a new branch of gapless surface Andreev bound states near the Fermi momentum. The latter is a new type of Andreev bound states resulting from both the nontrivial band structure and the odd-parity pairing symmetry. The tunneling spectra of these surface Andreev bound states agree well with a recent point-contact spectroscopy experiment [S. Sasaki et al., Phys. Rev. Lett. 107, 217001 (2011)] and yield additional predictions for low temperature tunneling and photoemission experiments.
Radiative and Pionic transitions from the $D_{s1}(2460)$ to the $D_{s0}^\\ast(2317)$
Xiao, cheng-Jian; Ma, Yong-Liang
2016-01-01
We estimate the partial widths for the radiative and pionic transitions from the $D_{s1}(2460)$ to the $D_{s0}(2317)$ in a molecule scenario, in which the $D_{s1}(2460)$ and $D_{s0}^\\ast(2317)$ are considered as hadronic molecule states of $DK$ and $D^\\ast K$, respectively. The partial widths for the $D_{s1}(2460) \\to D_{s0}^\\ast(2317) \\pi^0$ and $D_{s1}(2460) \\to D_{s0}^\\ast(2317) \\gamma$ are evaluated to be about $0.19 \\sim 0.22$ keV and $3.0 \\sim 3.1$ keV, respectively. In addition, the ratio of the $D_{s1}(2460) \\to D_{s0}(2317) \\gamma$ and $D_{s1}(2460) \\to D_{s}^\\ast \\pi^0$ is estimated to be about $(6.6\\sim 10.6) \\times 10^{-2}$, which is safely under the measured upper limit.
Nonlocal entanglement and noise between spin qubits induced by Majorana bound states
Energy Technology Data Exchange (ETDEWEB)
Ke, Sha-Sha [State Key Laboratory of Electronic Thin Films and Integrated Devices and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Lü, Hai-Feng, E-mail: lvhf81@gmail.com [State Key Laboratory of Electronic Thin Films and Integrated Devices and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong (China); Yang, Hua-Jun [State Key Laboratory of Electronic Thin Films and Integrated Devices and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Guo, Yong [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Zhang, Huai-Wu [State Key Laboratory of Electronic Thin Films and Integrated Devices and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)
2015-01-23
We propose a scheme to create nonlocal entanglement between two spatially separated electron spin qubits by coupling them with a pair of Majorana bound states (MBSs). The spin qubits are based on the spins of electrons confined in quantum dots. It is shown that spin entanglement between two dots could be generated by the nonlocality of MBSs. We also demonstrate that in the transport regime, the current noise cross correlation can serve as a good indicator of spin entanglement. The Majorana-dot coupling not only induces an indirect interaction between qubits, but also produces spin localization in the strong coupling limit. These two competing effects lead to a nonmonotonic dependence of current cross-correlation and entanglement on the Majorana-qubit coupling strength. - Highlights: • We propose a scheme to create nonlocal entanglement between two spatially separated electron spin qubits by coupling them with a pair of Majorana bound states. • Spin entanglement between two dots could be generated by the nonlocality of MBSs. • The current noise cross correlation can serve as a good indicator of spin entanglement.
Multiple-Pulse Operation and Bound States of Solitons in Passive Mode-Locked Fiber Lasers
Directory of Open Access Journals (Sweden)
A. Komarov
2012-01-01
Full Text Available We present results of our research on a multiple-pulse operation of passive mode-locked fiber lasers. The research has been performed on basis of numerical simulation. Multihysteresis dependence of both an intracavity energy and peak intensities of intracavity ultrashort pulses on pump power is found. It is shown that the change of a number of ultrashort pulses in a laser cavity can be realized by hard as well as soft regimes of an excitation and an annihilation of new solitons. Bound steady states of interacting solitons are studied for various mechanisms of nonlinear losses shaping ultrashort pulses. Possibility of coding of information on basis of soliton trains with various bonds between neighboring pulses is discussed. The role of dispersive wave emitted by solitons because of lumped intracavity elements in a formation of powerful soliton wings is analyzed. It is found that such powerful wings result in large bounding energies of interacting solitons in steady states. Various problems of a soliton interaction in passive mode-locked fiber lasers are discussed.
Three-Nucleon Bound States and the Wigner-SU(4) Limit
Vanasse, Jared; Phillips, Daniel R.
2017-03-01
We examine the extent to which the properties of three-nucleon bound states are well-reproduced in the limit that nuclear forces satisfy Wigner's SU(4) (spin-isospin) symmetry. To do this we compute the charge radii up to next-to-leading order (NLO) in an effective field theory that is an expansion in powers of R/ a, with R the range of the nuclear force and a the nucleon-nucleon (N N) scattering lengths. In the Wigner-SU(4) limit, the triton and helium-3 point charge radii are equal. At NLO in the range expansion both are 1.66 fm. Adding the first-order corrections due to the breaking of Wigner symmetry in the N N scattering lengths gives a ^3{H} point charge radius of 1.58 fm, which is remarkably close to the experimental number, 1.5978± 0.040 fm (Angeli and Marinova in At Data Nucl Data Tables 99:69-95, 2013). For the ^3{He} point charge radius we find 1.70 fm, about 4% away from the experimental value of 1.77527± 0.0054 fm (Angeli and Marinova 2013). We also examine the Faddeev components that enter the tri-nucleon wave function and find that an expansion of them in powers of the symmetry-breaking parameter converges rapidly. Wigner's SU(4) symmetry is thus a useful starting point for understanding tri-nucleon bound-state properties.
Wino dark matter annihilation through the radiative formation of bound states
Johnson, Evan; Zhang, Hong
2016-01-01
The most dramatic "Sommerfeld enhancements" of neutral-wino-pair annihilation occur when the wino mass is tuned to near critical values where there is a zero-energy S-wave resonance at the neutral-wino-pair threshold. If the wino mass is larger than the critical value, the resonance is a wino-pair bound state. If the wino mass is near a critical value, low-energy winos can be described by a zero-range effective field theory in which the winos interact nonperturbatively through a contact interaction. The parameters of the zero-range effective field theory can be determined by matching wino scattering amplitudes calculated by solving the Schr\\"odinger equation for a nonrelativistic effective field theory in which the winos interact through a potential due to the exchange of electroweak gauge bosons. The utility of the zero-range effective field theory is illustrated by calculating the rate for formation of an S-wave bound state in the collision of two neutral winos through the emission of two soft photons.
Low energy behavior of astrophysical S factor in radiative captures to loosely bound final states
Mukhamedzhanov, A M
2002-01-01
The low-energy behavior of the astrophysical S-factor for E1 direct radiative captures a(p,gamma)b leading to loosely bound final states (b=a+p) is investigated. We derive a first-order integral representation for S(E) and focus on the properties around zero energy. We show that it is the competition between various effects, namely the remnant Coulomb barrier, the initial and final centrifugal barriers and the binding energy, that defines the behavior of the S(E->0). Contrary to previous findings, we prove that S(E->0) is not determined by the pole corresponding to the bound state. The derivative S'(0) increases with the increase of the centrifugal barrier, while it decreases with the charge of the target. For l_i=l_f+1 the increase of the binding energy of the final nucleus increases the derivative S'(0) while for l_i=l_f-1 the opposite effect is found. We make use of our findings to explain the low energy behavior of the S-factors related to some notorious capture reactions: 7Be(p, gamma)8B, 14N(p,gamma)15O...
Isospin and particle representations for quasi-bound state of kaonic clusters
Filikhin, Igor; Kezerashvili, Roman; Vlahovic, Branislav
2017-01-01
In the framework of the method of the Faddeev equations in configuration space, the NNK (I = 0) (and KK) kaonic cluster system including two identical particles is considered. We use the formalism of isospin and particle representations to describe the systems. The treatment of I = 1 and I = 0 isospin KN channels is discussed. The presence of the Coulomb force in ppK- channel violates the isospin symmetry of the NNK (I = 0) system. According to the particle representation, NNK is a two-level system of coupled ppK- and ppnl channels with and without the Coulomb energy, respectively. The results of calculations for the bound states with the phenomenological and chiral motivated KN potentials are given for different representations. In particular, new single channel calculations for the ppK- (and K-K- p) cluster are presented. It is shown that the exchange of identical particles plays an important role in the formation of a bound state of the systems. The relation of the exchange and the three-body mass rearrangement effects is discussed. This work is supported by the National Science Foundation grant Supplement to the NSF grant HRD-1345219 and NASA (NNX09AV07A).
Efficient method for calculating electronic bound states in arbitrary one-dimensional quantum wells
de Aquino, V. M.; Iwamoto, H.; Dias, I. F. L.; Laureto, E.; da Silva, M. A. T.; da Silva, E. C. F.; Quivy, A. A.
2017-01-01
In the present paper it is demonstrated that the bound electronic states of multiple quantum wells structures may be calculated very efficiently by expanding their eigenstates in terms of the eigenfunctions of a particle in a box. The bound states of single and multiple symmetric or nonsymmetric wells are calculated within the single-band effective mass approximation. A comparison is then made between the results obtained for simple cases with exact calculations. We also apply our approach to a GaAs/AlGaAs multiple quantum well structure composed of forty periods each one with seven quantum wells. The method may be very useful to design narrow band quantum cascade photodetectors to work without applied bias in a photovoltaic mode. With the presented method the effects of a electric field may also be easily included which is very important if one desires study quantum well structures for application to the development of quantum cascade lasers. The advantages of the method are also presented.
Examination of experimental evidence of chaos in the bound states of 208Pb
Muñoz, L.; Molina, R. A.; Gómez, J. M. G.; Heusler, A.
2017-01-01
We study the spectral fluctuations of the 208Pb nucleus using the complete experimental spectrum of 151 states up to excitation energies of 6.20 MeV recently identified at the Maier-Leibnitz Laboratorium at Garching, Germany. For natural parity states the results are very close to the predictions of random matrix theory (RMT) for the nearest-neighbor spacing distribution. A quantitative estimate of the agreement is given by the Brody parameter ω , which takes the value ω =0 for regular systems and ω ≃1 for chaotic systems. We obtain ω =0.85 which is, to our knowledge, the closest value to chaos ever observed in experimental bound states of nuclei. By contrast, the results for unnatural parity states are far from RMT behavior. We interpret these results as a consequence of the strength of the residual interaction in 208Pb, which, according to experimental data, is much stronger for natural than for unnatural parity states. In addition, our results show that chaotic and nonchaotic nuclear states coexist in the same energy region of the spectrum.
Ichikawa, G; Komamiya, S; Kamiya, Y; Minami, Y; Tani, M; Geltenbort, P; Yamamura, K; Nagano, M; Sanuki, T; Kawasaki, S; Hino, M; Kitaguchi, M
2014-02-21
Ultracold neutrons (UCNs) can be bound by the potential of terrestrial gravity and a reflecting mirror. The wave function of the bound state has characteristic modulations. We carried out an experiment to observe the vertical distribution of the UCNs above such a mirror at the Institut Laue-Langevin in 2011. The observed modulation is in good agreement with that prediction by quantum mechanics using the Wigner function. The spatial resolution of the detector system is estimated to be 0.7 μm. This is the first observation of gravitationally bound states of UCNs with submicron spatial resolution.
Simulated Annealing for Ground State Energy of Ionized Donor Bound Excitons in Semiconductors
Institute of Scientific and Technical Information of China (English)
YANHai-Qing; TANGChen; LIUMing; ZHANGHao; ZHANGGui-Min
2004-01-01
We present a global optimization method, called the simulated annealing, to the ground state energies of excitons. The proposed method does not require the partial derivatives with respect to each variational parameter or solving an eigenequation, so the present method is simpler in software programming than the variational method,and overcomes the major difficulties. The ground state energies of ionized-donor-bound excitons (D+,X) have beencal culated variationally for all values of effective electron-to-hole mass ratio σ. They are compared with those obtained by the variational method. The results obtained demonstrate that the proposed method is simple, accurate, and has more advantages than the traditional methods in calculation.
Simulated Annealing for Ground State Energy of Ionized Donor Bound Excitons in Semiconductors
Institute of Scientific and Technical Information of China (English)
YAN Hai-Qing; TANG Chen; LIU Ming; ZHANG Hao; ZHANG Gui-Min
2004-01-01
We present a global optimization method, called the simulated annealing, to the ground state energies of excitons. The proposed method does not require the partial derivatives with respect to each variational parameter or solving an eigenequation, so the present method is simpler in software programming than the variational method,and overcomes the major difficulties. The ground state energies of ionized-donor-bound excitons (D+, X) have been calculated variationally for all values of effective electron-to-hole mass ratio σ. They are compared with those obtained by the variational method. The results obtained demonstrate that the proposed method is simple, accurate, and has more advantages than the traditional methods in calculation.
Collider Bounds on Indirect Dark Matter Searches: The $WW$ Final State
Lopez, Nicolas; Cotta, Randel; Frate, Meghan; Zhou, Ning; Whiteson, Daniel
2014-01-01
We describe an effective theory of interaction between pairs of dark matter particles (denoted $\\chi$) and pairs of $W$ bosons. Such an interaction could accommodate $\\chi\\bar{\\chi}\\rightarrow WW$ processes, which are a major focus of indirect dark matter experiments, as well as $pp \\rightarrow W\\rightarrow W\\chi\\bar{\\chi}$ processes, which would predict excesses at the LHC in the $W$+MET final-state. We reinterpret an ATLAS $W$+MET analysis in the hadronic mode and translate the bounds to the space of indirect detection signals. We also reinterpret the $W$+MET analysis in terms of graviton theory through the processes $W\\rightarrow WG$ and $Z\\rightarrow ZG$ in which $G$ is invisible. Finally, the final state is interpreted in terms of a $W'$ model where $W'\\rightarrow WZ$, where $W$ decays hadronically and $Z$ decays to neutrinos.
Observation of the ABC effect and final-state isospin
Doroshkevich, E. A.; Bashkanov, M. A.; Clement, H.; Perez del Rio, E.; Pricking, A.; Skorodko, T. Yu.; Wagner, G. J.
2014-07-01
Despite the number of inclusive measurements of the pionic fusion reactions, the nature of the ABC effect discovered in 1960 was not completely established. Exclusive measurements of the doublepion-production reactions leading to either fused d, 3He and 4He nuclear final states or pp pairs are analyzed. A significant ABC effect—enhancement in the region of low ππ mass—is found only in the isoscalar ππ channel while in the isovector channels it is small or absent. For the reaction with isovector pp final state an ABC effect was not observed even at the special kinematic conditions to reproduce a quasi-bound two-proton state. The total cross sections for the d and 4He fusion reactions show similar resonance-like energy dependence.
First clear evidence of quantum chaos in the bound states of an atomic nucleus
Muñoz, L; Gómez, J M G; Heusler, A
2016-01-01
We study the spectral fluctuations of the $^{208}$Pb nucleus using the complete experimental spectrum of 151 states up to excitation energies of $6.20$ MeV recently identified at the Maier-Leibnitz-Laboratorium at Garching, Germany. For natural parity states the results are very close to the predictions of Random Matrix Theory (RMT) for the nearest-neighbor spacing distribution. A quantitative estimate of the agreement is given by the Brody parameter $\\omega$, which takes the value $\\omega=0$ for regular systems and $\\omega \\simeq 1$ for chaotic systems. We obtain $\\omega=0.85 \\pm 0.02$ which is, to our knowledge, the closest value to chaos ever observed in experimental bound states of nuclei. By contrast, the results for unnatural parity states are far from RMT behavior. We interpret these results as a consequence of the strength of the residual interaction in $^{208}$Pb, which, according to experimental data, is much stronger for natural than for unnatural parity states. In addition our results show that ch...
Directory of Open Access Journals (Sweden)
Vincenzo Parente
2014-03-01
Full Text Available The scattering of Dirac electrons by topological defects could be one of the most relevant sources of resistance in graphene and at the boundary surfaces of a three-dimensional topological insulator (3D TI. In the long wavelength, continuous limit of the Dirac equation, the topological defect can be described as a distortion of the metric in curved space, which can be accounted for by a rotation of the Gamma matrices and by a spin connection inherited with the curvature. These features modify the scattering properties of the carriers. We discuss the self-energy of defect formation with this approach and the electron cross-section for intra-valley scattering at an edge dislocation in graphene, including corrections coming from the local stress. The cross-section contribution to the resistivity, ρ, is derived within the Boltzmann theory of transport. On the same lines, we discuss the scattering of a screw dislocation in a two-band 3D TI, like Bi1-xSbx, and we present the analytical simplified form of the wavefunction for gapless helical states bound at the defect. When a 3D TI is sandwiched between two even-parity superconductors, Dirac boundary states acquire superconductive correlations by proximity. In the presence of a magnetic vortex piercing the heterostructure, two Majorana states are localized at the two interfaces and bound to the vortex core. They have a half integer total angular momentum each, to match with the unitary orbital angular momentum of the vortex charge.
ABC Effect in Double-Pionic Fusion – a New Resonance?
Directory of Open Access Journals (Sweden)
Skorodko T.
2012-12-01
Full Text Available ABC effect, an intriguing low-mass enhancement in the ππ invariant mass spectrum — known since more than 50 years from inclusive measurements of double-pionic fusion reactions — is reexamined. To this end exclusive and kinematically complete high-statistics experiments of the fusion reactions to d, 3He and 4He have been carried out with WASA at COSY. These measurements cover the full energy region, where the ABC effect has been observed previously. They also complement the systematic measurements of nucleon-nucleon induced two-pion production. An isospin decomposition of all three basic double-pionic fusion reactions leading to the deuteron uniquely shows that solely the isoscalar reaction part exhibits the ABC effect tightly correlated with a narrow resonance structure in the total cross section. The peak energy of the resonance structure is about 90 MeV below the nominal ΔΔ threshold of 2 mΔ and its width of only 70 MeV is much less than the 2 ГΔ expected from the conventional t-channel ΔΔ process. Based on angular distributions the quantum numbers I(JP = 0(3+ have been assigned. In the double-pionic fusion reaction dd→4Heπ0π0 again the ABC effect is observed to be correlated with the appearance of a resonance-like structure in the total cross section at the same excess energy. From this we conclude that this resonance structure obviously is strong enough to survive even in nuclei.
Kalchmair, Stefan; Gansch, Roman; Genevet, Patrice; Zederbauer, Tobias; MacFarland, Donald; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Strasser, Gottfried; Capasso, Federico; Loncar, Marko
2016-04-01
Photonic crystal slabs have been subject to research for more than a decade, yet the existence of bound states in the radiation continuum (BICs) in photonic crystals has been reported only recently [1]. A BIC is formed when the radiation from all possible channels interferes destructively, causing the overall radiation to vanish. In photonic crystals, BICs are the result of accidental phase matching between incident, reflected and in-plane waves at seemingly random wave vectors [2]. While BICs in photonic crystals have been discussed previously using reflection measurements, we reports for the first time in-situ measurements of the bound states in the continuum in photonic crystal slabs. By embedding a photodetector into a photonic crystal slab we were able to directly observe optical BICs. The photonic crystal slabs are processed from a GaAs/AlGaAs quantum wells heterostructure, providing intersubband absorption in the mid-infrared wavelength range. The generated photocurrent is collected via doped contact layers on top and bottom of the suspended photonic crystal slab. We were mapping out the photonic band structure by rotating the device and by acquiring photocurrent spectra every 5°. Our measured photonic bandstructure revealed several BICs, which was confirmed with a rigorously coupled-wave analysis simulation. Since coupling to external fields is suppressed, the photocurrent measured by the photodetector vanishes at the BIC wave vector. To confirm the relation between the measured photocurrent and the Q-factor we used temporal coupled mode theory, which yielded an inverse proportional relation between the photocurrent and the out-coupling loss from the photonic crystal. Implementing a plane wave expansion simulation allowed us to identify the corresponding photonic crystal modes. The ability to directly measure the field intensity inside the photonic crystal presents an important milestone towards integrated opto-electronic BIC devices. Potential
Jamell, Christopher Ray
In this thesis, we focus on two broad categories of problems, exciton condensation and bound states, and two complimentary approaches, real and momentum space, to solve these problems. In chapter 2 we begin by developing the self-consistent mean field equations, in momentum space, used to calculate exciton condensation in semiconductor heterostructures/double quantum wells and graphene. In the double quantum well case, where we have one layer containing electrons and the other layer with holes separated by a distance d, we extend the analytical solution to the two dimensional hydrogen atom in order to provide a semi-quantitative measure of when a system of excitons can be considered dilute. Next we focus on the problem of electron-electron screening, using the random phase approximation, in double layer graphene. The literature contains calculations showing that when screening is not taken into account the temperature at which excitons in double layer graphene condense is approximately room temperature. Also in the literature is a calculation showing that under certain assumptions the transition temperature is approximately mK. The essential result is that the condensate is exponentially suppressed by the number of electron species in the system. Our mean field calculations show that the condensate, is in fact, not exponentially suppressed. Next, in chapter 3, we show the use of momentum space to solve the Schrodinger equation for a class of potentials that are not usually a part of a quantum mechanics courses. Our approach avoids the typical pitfalls that exist when one tries to discretize the real space Schrodinger equation. This technique widens the number of problems that can presented in an introductory quantum mechanics course while at the same time, because of the ease of its implementation, provides a simple introduction to numerical techniques and programming in general to students. We have furthered this idea by creating a modular program that allows
Isospin Decomposition of the Basic Double-Pionic Fusion in the Region of the ABC Effect
Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bednarski, T.; Bergmann, F. S.; Berlowski, M.; Bhatt, H.; Buescher, M.; Calen, H.; H. Clement; Coderre, Daniel; Czerwiński, E.; Demmich, K.; Doroshkevich, E.
2012-01-01
Exclusive and kinematically complete high-statistics measurements of the basic double pionic fusion reactions pn -> dpi0pi0, pn -> d pi+pi- and pp -> dpi+pi0 have been carried out simultaneously over the energy region of the ABC effect using the WASA detector setup at COSY. Whereas the isoscalar reaction part given by the dpi0pi0 channel exhibits the ABC effect, i.e. a low-mass enhancement in the pipi-invariant mass distribution, as well as the associated resonance structure in the total cros...
A phenomenological determination of the pion-nucleon scattering lengths from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2005-01-01
A model independent expression for the electromagnetic corrections to a phenomenological hadronic pion-nucleon scattering length, extracted from pionic hydrogen, is obtained. In a non-relativistic approach and using an extended charge distribution, these corrections are derived up to terms of order (alpha)**2 log(alpha) in the limit of a short-range hadronic interaction. We infer a charged pion-proton scattering length of 0.0870(5) in units of inverse pion mass, which gives for the charged pion-proton-neutron coupling, through the GMO relation, a value of 14.04(17).
ABC Effect in Basic Double-Pionic Fusion --- Observation of a new resonance?
Adlarson, P; Augustyniak, W; Baru, V; Bashkanov, M; Bergmann, F S; Berlowski, M; Bhatt, H; Brinkmann, K -T; Buescher, M; Calen, H; Clement, H; Coderre, D; Czerwinski, E; Doroshkevich, E; Ekstrom, C; Engels, R; Erven, W; Eyrich, W; Fedorets, P; Foehl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Grigoryev, K; Grishina, V; Gullstrom, C -O; Hampe, J; Hanhart, C; Heijkenskj, L; Hejny, V; Hinterberger, F; Hodana, M; Hoistad, B; Jacewicz, M; Janusz, M; Jany, A; Jany, B R; Jarczyk, L; Jaus, J; Johansson, T; Kamys, B; Kemmerling, G; Khakimova, O; Khoukaz, A; Kistryn, S; Klaja, J; Kleines, H; Klos, B; Kren, F; Krzemien, W; Kulessa, P; Kullander, S; Kupsc, A; Lalwani, K; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Marianski, B; Mikirtychiants, M; Moskal, P; Morsch, H -P; Nandi, B K; Ohm, H; Passfeld, A; Pauly, C; del Rio, E Perez; Petukhov, Y; Piskunov, N; Plucinski, P; Podkopal, P; Povtoreyko, A; Prasuhn, D; Pricking, A; Pysz, K; Rausmann, T; Redmer, C F; Ritman, J; Roy, A; Ruber, R J M Y; Rudy, Z; Schadmand, S; Schmidt, A; Schroeder, W; Sefzick, T; Serdyuk, V; Shah, N; Siemaszko, M; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Sterzenbach, G; Stockhorst, H; Stroeher, H; Szczurek, A; Taeschner, A; Tolba, T; Trzcinski, A; Varma, R; Vlasov, P; Wagner, G J; Weglorz, W; Winnemoeller, A; Wirzba, A; Wolke, M; Wronska, A; Wuestner, P; Wurm, P; Yurev, L; Zabierowski, J; Zielinski, M J; Zipper, W; Zlomanczuk, J; Zupranski, P
2011-01-01
We report on a high-statistics measurement of the basic double pionic fusion reaction $pn \\to d\\pi^0\\pi^0$ over the energy region of the so-called ABC effect, a pronounced low-mass enhancement in the $\\pi\\pi$-invariant mass spectrum. The measurements were performed with the WASA detector setup at COSY. The data reveal the ABC effect to be associated with a Lorentzian shaped energy dependence in the integral cross section. The observables are consistent with a resonance with $I(J^P) =0(3^+)$ in both $pn$ and $\\Delta\\Delta$ systems. Necessary further tests of the resonance interpretation are discussed.
Pionic charge exchange on the proton from 40 to 250 MeV
Breitschopf, J.; Bauer, M.; Clement, H.; Cröni, M.; Denz, H.; Friedman, E.; Gibson, E. F.; Meier, R.; Wagner, G. J.
2006-08-01
The total cross sections for pionic charge exchange on hydrogen were measured using a transmission technique on thin CH2 and C targets. Data were taken for π- lab energies from 39 to 247 MeV with total errors of typically 2% over the Δ-resonance and up to 10% at the lowest energies. Deviations from the predictions of the SAID phase shift analysis in the 60-80 MeV region are interpreted as evidence for isospin-symmetry breaking in the s-wave amplitudes. The charge dependence of the Δ-resonance properties appears to be smaller than previously reported.
The quark-gluon vertex in Landau gauge bound-state studies
Williams, Richard
2014-01-01
We present a practical method for the solution of the quark-gluon vertex for use in Bethe--Salpeter and Dyson--Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A model suitable for bound-state calculations is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within Rainbow-Ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required for practical calculations.
Ultraheavy Yukawa-bound states of fourth-generation at Large Hadron Collider
Indian Academy of Sciences (India)
Ts Enkhbat
2012-10-01
A study of bound states of the fourth-generation quarks in the range of 500–700 GeV is presented, where the binding energies are expected to be mainly of Yukawa origin, with QCD subdominant. Near degeneracy of their masses exhibits a new `isospin'. The production of a colour- octet, isosinglet vector meson via $q\\bar{q} → g$ is the most interesting. Its leading decay modes are $_{8}^{±} W^{\\mp}$, $_{8}^{0} Z^{0}$, and constituent quark decay, with $q\\bar{q}$ and $t\\bar{t'}$ and $b\\bar{b'}$ subdominant. The colour octet, isovector pseudoscalar 8 meson decays via constituent quark decay, or to $W g$. This work calls for more detailed study of fourth-generation phenomena at LHC.
Bloch bound states in the radiation continuum in a periodic array of dielectric rods
Bulgakov, Evgeny N
2014-01-01
We consider an infinite periodic array of dielectric rods in vacuum with the aim to demonstrate three types of a Bloch bound states in the continuum (BSC), symmetry protected with a zero Bloch vector, embedded into one diffraction channel with nonzero Bloch vector, and embedded into two and three diffraction channels. The first and second types of the BSC exist in a wide range of material parameters of the rods, while the third occurs only at a specific value of the radius of the rods. We show that the second type supports the power flux along the array. In order to find BSC we put forward an approach based on the expansion over the Hankel functions. We show how the BSC reveals itself in the scattering function when the singular BSC point is approached along a specific path in the parametric space.
Robust bound states in the continuum in Kerr microcavity embedded in photonic crystal waveguide
Bulgakov, Evgeny N
2014-01-01
We present a two-dimensional photonic crystal design with a microcavity of four defect dielectric rods with eigenfrequencies residing in the propagating band of directional waveguide. In the linear case for tuning of material parameters of defect rods the nonrobust bound state in the continuum (BSC) might occur. The BSC is a result of full destructive interference of resonant monopole and quadrupole modes with the same parity. % to trap light interior of the microcavity. A robust BSC arises in a self-adaptive way without necessity to tune the parameters of the microcavity with the Kerr effect. Lack of the superposition principle in nonlinear systems gives rise to coupling of the BSC with injecting light. That forms a peculiar shape of isolated transmittance resonance around BSC frequency. We show if injecting light is switched off the BSC storages light that opens a way for light accumulation.
Toward the Application of Three-Dimensional Approach to Few-body Atomic Bound States
Directory of Open Access Journals (Sweden)
Hadizadeh M.R.
2010-04-01
Full Text Available The ﬁrst step toward the application of an eﬀective non partial wave (PW numerical approach to few-body atomic bound states has been taken. The two-body transition amplitude which appears in the kernel of three-dimensional Faddeev-Yakubovsky integral equations is calculated as function of two-body Jacobi momentum vectors, i.e. as a function of the magnitude of initial and ﬁnal momentum vectors and the angle between them. For numerical calculation the realistic interatomic interactions HFDHE2, HFD-B, LM2M2 and TTY are used. The angular and momentum dependence of the fully oﬀ-shell transition amplitude is studied at negative energies. It has been numerically shown that, similar to the nuclear case, the transition amplitude exhibits a characteristic angular behavior in the vicinity of 4He dimer pole.
Model Study of Three-Body Forces in the Three-Body Bound State
Liu, H; Glöckle, W; Elster, Ch.
2003-01-01
The Faddeev equations for the three-body bound state with two- and three-body forces are solved directly as three-dimensional integral equation. The numerical feasibility and stability of the algorithm, which does not employ partial wave decomposition is demonstrated. The three-body binding energy and the full wave function are calculated with Malfliet-Tjon-type two-body potentials and scalar Fujita-Miyazawa type three-body forces. The influence of the strength and range of the three-body force on the wave function, single particle momentum distributions and the two-body correlation functions are studied in detail. The extreme case of pure three-body forces is investigated as well.
Logarithms of alpha in QED bound states from the renormalization group
Manohar; Stewart
2000-09-11
The velocity renormalization group is used to determine lnalpha contributions to QED bound state energies. The leading-order anomalous dimension for the potential gives the alpha(5)lnalpha Lamb shift. The next-to-leading-order anomalous dimension determines the alpha(6)lnalpha, alpha(7)ln (2)alpha, and alpha(8)ln (3)alpha corrections to the energy. These are used to obtain the alpha(8)ln (3)alpha Lamb shift and alpha(7)ln (2)alpha hyperfine splitting for hydrogen, muonium, and positronium, as well as the alpha(2)lnalpha and alpha(3)ln (2)alpha corrections to the ortho- and parapositronium lifetimes. This shows for the first time that these logarithms can be computed from the renormalization group.
Xie, Hang; Sha, Wei E I
2015-01-01
Numerical methods are developed in the quantum transport calculations for electron in the waveguides with spin-orbital (Rashba) interaction. The methods are based on a hybrid mode-matching scheme in which the wavefunctions are expressed as the superposition of eigenmodes in the lead regions and in the device region the wavefunction is expressed on the discrete basis. Two versions are presented for the lead without and with the Rashba interaction. In the latter case the eigenmodes are obtained from a quadratic eigenproblem calculation. These methods are suitable for the systems with variable geometries or arbitrary potential profiles. The computation can be effectively accelerated by the sparse matrix technique. We also investigate the Fano-Rashba bound states in the Rashba waveguides by some nonlinear eigenstate calculation. This calculation is based on a mode-matching method and self-consistent results are obtained in our calculations.
Macroscopic manipulation of high-order-harmonic generation through bound-state coherent control.
Hadas, Itai; Bahabad, Alon
2014-12-19
We propose a paradigm for macroscopic control of high-order harmonic generation by modulating the bound-state population of the medium atoms. A unique result of this scheme is that apart from regular spatial quasi-phase-matching (QPM), also purely temporal QPM of the emitted radiation can be established. Our simulations demonstrate temporal QPM by inducing homogenous Rabi oscillations in the medium and also spatial QPM by creating a grating of population inversion using the process of rapid adiabatic passage. In the simulations a scaled version of high-order harmonic generation is used: a far off-resonance 2.6 μm source generates UV-visible high-order harmonics from alkali-metal-atom vapor, while a resonant near IR source is used to coherently control the medium.
Park, Sunghun; Recher, Patrik
2015-12-11
A phase from an adiabatic exchange of Majorana bound states (MBS) reveals their exotic anyonic nature. For detecting this exchange phase, we propose an experimental setup consisting of a Corbino geometry Josephson junction on the surface of a topological insulator, in which two MBS at zero energy can be created and rotated. We find that if a metallic tip is weakly coupled to a point on the junction, the time-averaged differential conductance of the tip-Majorana coupling shows peaks at the tip voltages eV=±(α-2πl)ℏ/T_{J}, where α=π/2 is the exchange phase of the two circulating MBS, T_{J} is the half rotation time of MBS, and l an integer. This result constitutes a clear experimental signature of Majorana fermion exchange.
Variational Worldline Approximation for the Relativistic Two-Body Bound State in a Scalar Model
Barro-Bergfl"odt, K; Stingl, M
2006-01-01
We use the worldline representation of field theory together with a variational approximation to determine the lowest bound state in the scalar Wick-Cutkosky model where two equal-mass constituents interact via the exchange of mesons. Self-energy and vertex corrections are included approximately in a consistent way as well as crossed diagrams. Only vacuum-polarization effects of the heavy particles are neglected. In a path integral description of an appropriate current-current correlator an effective, retarded action is obtained by integrating out the meson field. As in the polaron problem we employ a quadratic trial action with variational functions to describe retardation and binding effects through multiple meson exchange.The variational equations for these functions are derived, discussed qualitatively and solved numerically. We compare our results with the ones from traditional approaches based on the Bethe-Salpeter equation and find an enhanced binding. For weak coupling this is worked out analytically ...
Photonic Bound State in the Continuum for Strong Light-matter Interaction
Zou, Chang-Ling; Sun, Fang-Wen; Xiong, Xiao; Zou, Xu-Bo; Han, Zheng-Fu; Guo, Guang-Can
2013-01-01
The photonic bound state in the continuum (BIC) is discovered in a hybrid photonic circuit with low refractive index waveguide on a high refractive index thin membrane, where the optical dissipation is forbidden because of the destructive interference of different leakage channels. Based on the photonic BIC, the low mode area in a hybrid waveguide and high quality factor in a microresonator can be applied to enhance the light-matter interaction. Taking the fabrication-friendly polymer structure on diamond membrane as an example, those excellent optical performances can exist in a wide range of structure parameters with large fabrication tolerance and induce the strong coupling between photon and nitrogen-vacancy center in the diamond for scalable quantum information processors and networks. Such a fabrication-friendly structure with photonic BIC is also very promising in laser, nonlinear optical and quantum optical applications.
Toward the Application of Three-Dimensional Approach to Few-body Atomic Bound States
Hadizadeh, M R
2010-01-01
The first step toward the application of an effective non partial wave (PW) numerical approach to few-body atomic bound states has been taken. The two-body transition amplitude which appears in the kernel of three-dimensional Faddeev-Yakubovsky integral equations is calculated as function of two-body Jacobi momentum vectors, i.e. as a function of the magnitude of initial and final momentum vectors and the angle between them. For numerical calculation the realistic interatomic interactions HFDHE2, HFD-B, LM2M2 and TTY are used. The angular and momentum dependence of the fully off-shell transition amplitude is studied at negative energies. It has been numerically shown that, similar to the nuclear case, the transition amplitude exhibits a characteristic angular behavior in the vicinity of 4He dimer pole.
The Problem of Mass: Mesonic Bound States Above T_c
Park, H J; Brown, G E; Park, Hong-Jo; Lee, Chang-Hwan; Brown, Gerald E.
2005-01-01
We discuss the problem of mass, noting that meson masses decrease with increasing scale as the dynamically generated condensate of "soft glue" is melted (Brown/Rho scaling). We then extend the Bielefeld LGS color singlet interaction computed for heavy quarks in a model-dependent way by including the Ampere law velocity-velocity interaction. Parameterizing the resulting interaction in terms of effective strength of the potential and including screening, we find that the masses of pi, sigma, rho and A1 excitations, 32 degrees of freedom in all, go to zero (in the chiral limit) as T goes to Tc essentially independently of the input quark (thermal) masses in the range of 1-2 GeV, calculated also in Bielefeld. We discuss other LGS which show q-bar q bound states, which we interpret as our chirally restored mesons, for T > Tc.
Relativistic Three-Quark Bound States in Separable Two-Quark Approximation
Öttel, M; Alkofer, R
2002-01-01
Baryons as relativistic bound states in 3-quark correlations are described by an effective Bethe-Salpeter equation when irreducible 3-quark interactions are neglected and separable 2-quark correlations are assumed. We present an efficient numerical method to calculate the nucleon mass and its covariant wave function in this quantum field theoretic quark-diquark model with quark-exchange interaction. Expanding the components of the spinorial wave function in terms of Chebyshev polynomials, the four-dimensional integral equations are in a first step reduced to a coupled set of one-dimensional ones. This set of linear and homogeneous equations defines a generalised eigenvalue problem. Representing the eigenvector corresponding to the largest eigenvalue, the Chebyshev moments are then obtained by iteration. The nucleon mass is implicitly determined by the eigenvalue, and its covariant wave function is reconstructed from the moments within the Chebyshev approximation.
Tunable optical bound states in the continuum beyond in-plane symmetry protection
Ni, Liangfu; Wang, Zhixin; Peng, Chao; Li, Zhengbin
2016-12-01
The formation of tunable bound states in the continuum (BICs) within photonic crystal (PC) slabs has been investigated by using a semianalytical coupled-wave theory framework. An analytic expression of the radiative wave has been derived in order to depict the condition of BICs. As a result, in addition to well-known symmetry-protected BICs, a novel type of vertical-cancellation BIC can be realized through continuously varying a given parameter to eliminate radiative waves at the boundaries. We investigated one-dimensional and two-dimensional (2D) periodic structures, and found that such tunable BICs can occur for a wide range of wave vectors by the selection of appropriate slab thicknesses. For a 2D PC slab, a ring of high-Q modes is predicted and confirmed by numerical simulation.
Nagaraju, Mulpuri; McGowan, Lauren C; Hamelberg, Donald
2013-02-25
Human Cyclophilin A (CypA) catalyzes cis-trans isomerization of the prolyl peptide ω-bond in proteins and is involved in many subcellular processes. CypA has, therefore, been identified as a potential drug target in many diseases, and the development of potent inhibitors with high selectivity is a key objective. In computer-aided drug design, selectivity is improved by taking into account the inherent flexibility of the receptor. However, the relevant receptor conformations to focus on in order to develop highly selective inhibitors are not always obvious from available X-ray crystal structures or ensemble of conformations generated using molecular dynamics simulations. Here, we show that the conformation of the active site of CypA varies as the substrate configuration changes during catalytic turnover. We have analyzed the principal modes of the active site dynamics of CypA from molecular dynamics simulations to show that similar ensembles of enzyme conformations recognize diverse inhibitors and bind the different configurations of the peptide substrate. Small nonpeptidomimetic inhibitors with varying activity are recognized by enzyme ensembles that are similar to those that tightly bind the transition state and cis configurations of the substrate. Our results suggest that enzyme-substrate ensembles are more relevant in structure-based drug design for CypA than free enzyme. Of the vast conformational space of the free enzyme, the enzyme conformations of the tightly bound enzyme-substrate complexes are the most important for catalysis. Therefore, functionalizing lead compounds to optimize their interactions with the enzyme's conformational ensemble bound to the substrate in the cis or the transition state could lead to more potent inhibitors.
Improved Lower Bounds on the Compatibility of Multi-State Characters
Shutters, Brad; Fernández-Baca, David
2012-01-01
We study a long standing conjecture on the necessary and sufficient conditions for the compatibility of multi-state characters: There exists a function $f(r)$ such that, for any set $C$ of $r$-state characters, $C$ is compatible if and only if every subset of $f(r)$ characters of $C$ is compatible. We show that for every $r \\ge 2$, there exists an incompatible set $C$ of $\\lfloor\\frac{r}{2}\\rfloor\\cdot\\lceil\\frac{r}{2}\\rceil + 1$ $r$-state characters such that every proper subset of $C$ is compatible. Thus, $f(r) \\ge \\lfloor\\frac{r}{2}\\rfloor\\cdot\\lceil\\frac{r}{2}\\rceil + 1$ for every $r \\ge 2$. This improves the previous lower bound of $f(r) \\ge r$ given by Meacham (1983), and generalizes the construction showing that $f(4) \\ge 5$ given by Habib and To (2011). We prove our result via a result on quartet compatibility that may be of independent interest: For every integer $n \\ge 4$, there exists an incompatible set $Q$ of $\\lfloor\\frac{n-2}{2}\\rfloor\\cdot\\lceil\\frac{n-2}{2}\\rceil + 1$ quartets over $n$ labels...
Shen, Bo; Wang, Zidong; Liu, Xiaohui
2011-01-01
In this paper, new synchronization and state estimation problems are considered for an array of coupled discrete time-varying stochastic complex networks over a finite horizon. A novel concept of bounded H(∞) synchronization is proposed to handle the time-varying nature of the complex networks. Such a concept captures the transient behavior of the time-varying complex network over a finite horizon, where the degree of bounded synchronization is quantified in terms of the H(∞)-norm. A general sector-like nonlinear function is employed to describe the nonlinearities existing in the network. By utilizing a time-varying real-valued function and the Kronecker product, criteria are established that ensure the bounded H(∞) synchronization in terms of a set of recursive linear matrix inequalities (RLMIs), where the RLMIs can be computed recursively by employing available MATLAB toolboxes. The bounded H(∞) state estimation problem is then studied for the same complex network, where the purpose is to design a state estimator to estimate the network states through available output measurements such that, over a finite horizon, the dynamics of the estimation error is guaranteed to be bounded with a given disturbance attenuation level. Again, an RLMI approach is developed for the state estimation problem. Finally, two simulation examples are exploited to show the effectiveness of the results derived in this paper.
Foley, M S; Beeby, A; Parker, A W; Bishop, S M; Phillips, D
1997-03-01
The binding of the sulphonated aluminum phthalocyanines to human serum albumin (HSA) in aqueous phosphate buffer solution at 25 degrees C has been studied by measuring the properties of the triplet excited states of these dyes. The triplet lifetimes were measured by triplet-triplet absorption flash photolysis. The triplet lifetime of the disulphonated AlS2Pc (2.5 microM) varies from 500 +/- 30 microseconds in the absence of protein to 1.100 microseconds and longer with HSA concentrations above 100 microM. Under identical conditions, the maximum triplet lifetimes of the mono-, tri- and tetrasulphonated compounds bound to HSA are shorter than those for the disulphonated species. The increase in the triplet state lifetimes is attributed to the ability of the bulk aqueous phase to interact with the sensitizer at the site of binding; the site of binding being dependent on the degree of sulphonation. For AlS2Pc and AlS3Pc at all HSA concentrations, and regardless of the degree of sulphonation, all the triplet state decay profiles follow simple pseudo-first-order kinetics. The exponential decay of the triplet phthalocyanine at all HSA concentrations is ascribed to the rapid association and dissociation of the phthalocyanine-HSA complex on the time-scales of the triplet state lifetimes. A simplified one-step binding model is utilized to describe the results. The association of AlS1Pc with HSA results in substantial quenching of the triplet state quantum yield, and a more complex model is required to analyze the results. The tetrasulphonated compound (AlS4Pc) binds to the protein at a site where it experiences some protection from the aqueous phase.
Total reaction cross sections for 20-30 MeV pions and the anomaly of pionic atoms
Friedman, E.; Goldring, A.; Johnson, R. R.; Meirav, O.; Vetterli, D.; Weber, P.; Altman, A.
1991-03-01
Total reaction cross sections of 20 MeV π- and 30 MeV π+ and π- have been measured for carbon and nickel targets. The experimental results are in very good agreement with calculations based on commonly accepted pion-nucleus potentials but disagree with calculations based on the potentials associated with the so-called pionic atom anomaly.
Fano effect and Andreev bound states in a hybrid superconductor–ferromagnetic nanostructure
Energy Technology Data Exchange (ETDEWEB)
Siqueira, E.C., E-mail: ezcostta@gmail.com [Departamento de Física, Universidade Tecnológica Federal do Paraná – UTFPR, 84016210, Ponta Grossa, PR (Brazil); Orellana, P.A. [Departamento de Física, Universidad Técnica Federico Santa Maria, Av. Vicuña Mackenna 3939, Santiago (Chile); Cestari, R.C. [Departamento de Física e Química, Universidade Estadual Paulista – UNESP, 15385-000, Ilha Solteira, SP (Brazil); Figueira, M.S. [Instituto de Física, Universidade Federal Fluminense, 24210-340, Niterói, RJ (Brazil); Cabrera, G.G. [Instituto de Física ‘Gleb Wataghin’, Universidade Estadual de Campinas – UNICAMP, Campinas 13083-859, SP (Brazil)
2015-10-16
In this work, it is considered a hybrid nanostructure composed by a quantum dot coupled to two ferromagnetic leads and a superconductor lead. It is shown that the zero-bias transmittance for the co-tunneling between the ferromagnetic leads presents Fano anti-resonances due to the destructive interference between the two spin channels mixing by the relative orientation of the magnetizations in the leads. When the superconductor is coupled to the system, electron–hole correlations between different spin states lead to a resonance in the place of the dip appearing in the transmittance. Such an effect is accompanied by two Fano anti-resonances explained by a “leakage” of conduction channels from the co-tunneling to the Andreev transport. In the non-equilibrium regime, correlations within the quantum dot introduce a dependence of the resonance condition on the finite bias applied to the ferromagnetic leads. However, it is still possible to observe signatures of the same interference effect in the electrical current. - Highlights: • We have studied an hybrid nanostructure composed by quantum dot coupled to a superconductor and two ferromagnets. • The interplay between spin polarization and Andreev bound states leads to a Fano-like effect. • The Fano-like effect manifests as a resonance in the transmittance for the transport between the ferromagnets.
Electron-electron bound states in Maxwell-Chern-Simons-Proca QED{sub 3}
Energy Technology Data Exchange (ETDEWEB)
Belich, H.; Helayel-Neto, J.A. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil)]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]. E-mail: belich@cbpf.br; helayel@gft.ucp.br; Del Cima, O.M. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil)]. E-mail: delcima@gft.ucp.br; Ferreira, M.M. Jr. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil)]|[Maranhao Univ., Sao Luis, MA (Brazil). Dept. de Fisica]. E-mail: manojr@cbpf.br
2002-10-01
We start from a parity-breaking MCS QED{sub 3} model with spontaneous breaking of the gauge symmetry as a framework for evaluation of the electron-electron interaction potential and for attainment of numerical values for the e{sup -}e{sup -} - bound state. Three expressions (V{sub eff{down_arrow}}{sub {down_arrow}}, V{sub eff{down_arrow}}{sub {up_arrow}}, V{sub eff{down_arrow}}{sub {down_arrow}}) are obtained according to the polarization state of the scattered electrons. In an energy scale compatible with condensed matter electronic excitations, these potentials become degenerated. The resulting potential is implemented in the Schroedinger equation and the variational method is applied to carry out the electronic binding energy. The resulting binding energies in the scale of 10-100 meV and a correlation length in the scale of 10 - 30 Angstrom are possible indications that the MCS-QED{sub 3} model adopted may be suitable to address an eventual case of e{sup -}e{sup -} pairing in the presence of parity-symmetry breakdown. The data analyzed here suggest an energy scale of 10-100 meV to fix the breaking of the U(1)-symmetry. (author)
Variational Mass Perturbation Theory for Light-Front Bound-State Equations
Harada, K; Stern, C; Harada, Koji; Heinzl, Thomas; Stern, Christian
1998-01-01
We investigate the mesonic light-front bound-state equations of the 't Hooft and Schwinger model in the two-particle, i.e. valence sector, for small fermion mass. We perform a high precision determination of the mass and light-cone wave function of the lowest lying meson by combining fermion mass perturbation theory with a variational approach. All calculations are done entirely in the fermionic representation without using any bosonization scheme. In a step-by-step procedure we enlarge the space of variational parameters. For the first two steps, the results are obtained analytically. Beyond that we use computer algebraic and numerical methods. We achieve good convergence so that the calculation of the meson mass squared can be extended to third order in the fermion mass. Within the numerical treatment we include higher Fock states up to six particles. Our results are consistent with all previous numerical investigations, in particular lattice calculations. For the massive Schwinger model, we find a small di...
Energy Technology Data Exchange (ETDEWEB)
Zolotovskii, I O; Korobko, D A; Okhotnikov, O G [Ulyanovsk State University, Ulyanovsk (Russian Federation); Gumenyuk, R V [Optoelectronics Research Center, Tampere University of Technology, Tampere (Finland)
2015-01-31
A numerical model of a soliton fibre laser with a semiconductor saturable absorber mirror (SESAM), characterised by the complex dynamics of absorption relaxation, is considered. It is shown that stationary bound states of pulses can be formed in this laser as a result of their interaction via the dispersion-wave field. The stability of stationary bound states of several pulses is analysed. It is shown that an increase in the number of pulses in a stationary bound state leads eventually to its decay and formation of a random bunch. It is found that the bunch stability is caused by the manifestation of nonlinear self-phase modulation, which attracts pulses to the bunch centre. The simulation results are in qualitative agreement with experimental data. (nonlinear optical phenomena)
On Possible S-Wave Bound States for an N-(N) System Within a Constituent Quark Model
Institute of Scientific and Technical Information of China (English)
CHANG Chao-Hsi; PANG Hou-Rong
2005-01-01
We try to apply a constituent quark model (a variety chiral constituent quark model) and the resonating group approach for the multi-quark problems to compute the effective potential between the NN- in S-wave (the quarks in the nucleons N and N-, and the two nucleons relatively as well, are in S wave) so as to see the possibility if there may be a tight bound state of six quarks as indicated by a strong enhancement at threshold of pp- in J/ψ and B decays. The effective potential which we obtain in terms of the model and approach shows if the experimental enhancement is really caused by a tight S-wave bound state of six quarks, then the quantum number of the bound state is very likely to be I = 1, JPC= 0-+.
The bound state S-matrix for AdS{sub 5}xS{sup 5} superstring
Energy Technology Data Exchange (ETDEWEB)
Arutyunov, G. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)], E-mail: g.e.arutyunov@uu.nl; Leeuw, M. de [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)], E-mail: m.deleeuw@uu.nl; Torrielli, A. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)], E-mail: a.torrielli@uu.nl
2009-10-01
We determine the S-matrix that describes scattering of arbitrary bound states in the light-cone string theory in AdS{sub 5}xS{sup 5}. The corresponding construction relies on the Yangian symmetry and the superspace formalism for the bound state representations. The basic analytic structure supporting the S-matrix entries turns out to be the hypergeometric function {sub 4}F{sub 3}. We show that for particular bound state numbers it reproduces all the scattering matrices previously obtained in the literature. Our findings should be relevant for the TBA and Luescher approaches to the finite-size spectral problem. They also shed some light on the construction of the universal R-matrix for the centrally-extended psu(2|2) superalgebra.
Bound states in the 3d Ising model and implications for QCD at finite temperature and density
Caselle, M; Provero, P; Zarembo, K
2002-01-01
We study the spectrum of bound states of the three dimensional Ising model in the (h,beta) plane near the critical point. We show the existence of an unbinding line, defined as the boundary of the region where bound states exist. Numerical evidence suggests that this line coincides with the beta=beta_c axis. When the 3D Ising model is considered as an effective description of hot QCD at finite density, we conjecture the correspondence between the unbinding line and the line that separates the quark-gluon plasma phase from the superconducting phase. The bound states of the Ising model are conjectured to correspond to the diquarks of the latter phase of QCD.
DEFF Research Database (Denmark)
Sadrieva, Z. F.; Sinev, I. S.; Samusev, A. K.;
2016-01-01
In this work, we implement CMOS-compatible one-dimensional photonic structure based on silicon-on-insulator wafer supporting optical bound states in the continuum at telecommunication wavelengths — localized optical state with energy lying above the light line of the surrounding space. Such high-......-Q states are very promising for many potential applications ranging from on-chip photonics and optical communications to biological sensing and photovoltaics....
Diphoton decay of the Higgs boson and new bound states of top and anti-top quarks
Froggatt, C D; Laperashvili, L V; Nielsen, H B
2015-01-01
We consider the constraints, provided by the LHC results on Higgs boson decay into 2 photons and its production via gluon fusion, on the previously proposed Standard Model (SM) strongly bound state $S$ of 6 top quarks and 6 anti-top quarks. A correlation is predicted between the ratios $\\kappa_{\\gamma}$ and $\\kappa_g$ of the Higgs diphoton decay and gluon production amplitudes respectively to their SM values. We estimate the contribution to these amplitudes from one loop diagrams involving the 12 quark bound state $S$ and related excited states using an atomic physics based model. We find two regions of parameter space consistent with the ATLAS and CMS data on ($\\kappa_{\\gamma}$, $\\kappa_g$) at the 3 sigma level: a region close to the SM values ($\\kappa_{\\gamma}=1$, $\\kappa_g =1$) with the mass of the bound state $m_S > 400$ GeV and a region with ($\\kappa_{\\gamma} \\sim 3/2$, $\\kappa_g \\sim -3/4$) corresponding to a bound state mass of $m_S \\sim 220$ GeV.
Johansen, J G; Borge, M J G; Cubero, M; Diriken, J; Elsevier, J; Fraile, L M; Fynbo, H O U; Gaffney, L P; Gernhäuser, R; Jonson, B; Koldste, G T; Konki, J; Kröll, T; Krücken, R; Mücher, D; Nilsson, T; Nowak, K; Pakarinen, J; Pesudo, V; Raabe, R; Riisager, K; Seidlitz, M; Tengblad, O; Törnqvist, H; Voulot, D; Warr, N; Wenander, F; Wimmer, K; De Witte, H
2013-01-01
The bound states of $^{12}$Be have been studied through a $^{11}$Be$(d,p)^{12}$Be transfer reaction experiment in inverse kinematics. A 2.8 MeV/u beam of $^{11}$Be was produced using the REX-ISOLDE facility at CERN. The outgoing protons were detected with the T-REX silicon detector array. The MINIBALL germanium array was used to detect $\\gamma$-rays from the excited states in $^{12}$Be. The $\\gamma$-ray detection enabled a clear identification of the four known bound states in $^{12}$Be, and each of the states has been studied individually. Differential cross sections over a large angular range have been extracted. Spectroscopic factors for each of the states have been determined from DWBA calculations and have been compared to previous experimental and theoretical results.
Shot noise as a measure of the lifetime and energy splitting of Majorana bound states
Energy Technology Data Exchange (ETDEWEB)
Lü, Hai-Feng; Guo, Zhen; Ke, Sha-Sha; Zhang, Huai-Wu [State Key Laboratory of Electronic Thin Films and Integrated Devices and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Guo, Yong [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China)
2015-04-28
We propose a scheme to measure the lifetime and energy splitting of a pair of Majorana bound states at the ends of a superconducting nanowire by using the shot noise in a dynamical channel blockade system. A quantum dot is coupled to one end of the wire and connected with two electron reservoirs. It is found that a finite Majorana energy splitting tends to produce a super-Poissonian shot noise, while Majorana relaxation process relieves the dynamical channel blockade and suppresses the noise Fano factor. When the dot energy level locates in the middle of the gap of topological superconductor, the Fano factor is independent on Majorana lifetime and Majorana energy splitting is thus extracted. For a finite energy splitting, we could evaluate the Majorana relaxation rate from the suppression of Fano factor. Under a realistic condition, the expected resolution of Majorana energy splitting and its relaxation rate calculated from our model are about 1μeV and 0.01−1μeV, respectively.
Black hole bound states in AdS_3 x S^2
de Boer, Jan; El-Showk, Sheer; Messamah, Ilies; Bleeken, Dieter Van den
2008-01-01
We systematically construct the geometries dual to the 1+1 dimensional (0,4) conformal field theories that arise in the low-energy description of wrapped M5-branes in S^1 x CY_3 compactifications of M-theory. This includes a large number of multicentered black hole bound states asymptotic to AdS_3 x S^2. In addition, we find many geometries that develop multiple, mutually decoupled AdS_3 x S^2 throats. We argue there is a useful one to one correspondence between the connected components of the space of solutions and particular limits of type IIA attractor flow trees. We point out that there is a thermodynamic instability of small supersymmetric BTZ black holes to localization on the S^2, a supersymmetric and exactly solvable analog of the well known AdS-Schwarzschild localization instability, and identify this with the ``Entropy Enigma'' in four dimensions. We discuss the phase transition this suggests, and initiate the CFT interpretation of these results.
Three-nucleon bound states and the Wigner-SU(4) limit
Vanasse, Jared
2016-01-01
We examine the extent to which the properties of three-nucleon bound states are well-reproduced in the limit that nuclear forces satisfy Wigner's SU(4) (spin-isospin) symmetry. To do this we compute the charge radii up to next-to-leading order (NLO) in an effective field theory (EFT) that is an expansion in powers of $R/a$, with $R$ the range of the nuclear force and $a$ the nucleon-nucleon ($N\\!N$) scattering lengths. In the Wigner-SU(4) limit, the triton and Helium-3 point charge radii are equal. At NLO in the range expansion both are $1.66$ fm. Adding the first-order corrections due to the breaking of Wigner symmetry in the $N\\!N$ scattering lengths gives a ${}^3\\mathrm{H}$ point charge radius of $1.58$ fm, which is remarkably close to the experimental number, $1.5978\\pm0.040$ fm. For the ${}^3\\mathrm{He}$ point charge radius we find $1.70$ fm, about 4% away from the experimental value of $1.77527\\pm0.0054$ fm. We also examine the Faddeev components that enter the tri-nucleon wave function and find that an...
Formation and condensation of excitonic bound states in the generalized Falicov-Kimball model
Farkašovský, Pavol
2017-01-01
The density-matrix-renormalization-group method and the Hartree-Fock approximation with the charge-density-wave instability are used to study a formation and condensation of excitonic bound states in the generalized Falicov-Kimball model. In particular, we examine effects of various factors, such as the f -electron hopping, the local and nonlocal hybridizations, as well as the increasing dimension of the system on the excitonic momentum distribution N (q ) and especially on the number of zero-momentum excitons N0=N (q =0 ) in the condensate. It is found that the negative values of the f -electron hopping integrals tf support the formation of a zero-momentum condensate, whereas the positive values of tf have the fully opposite effect. The opposite effects on the formation of the condensate exhibit also the local and nonlocal hybridizations. The first one strongly supports the formation of the condensate, whereas the second one destroys it completely. Moreover, it was shown that the zero-momentum condensate remains robust with increasing dimension of the system.
Ab initio potential energy surface and bound states for the Kr-OCS complex.
Feng, Eryin; Sun, Chunyan; Yu, Chunhua; Shao, Xi; Huang, Wuying
2011-09-28
The first ab initio potential energy surface of the Kr-OCS complex is developed using the coupled-cluster singles and doubles with noniterative inclusion of connected triples [CCSD(T)]. The mixed basis sets, aug-cc-pVTZ for the O, C, and S atom, and aug-cc-pVQZ-PP for the Kr atom, with an additional (3s3p2d1f) set of midbond functions are used. A potential model is represented by an analytical function whose parameters are fitted numerically to the single point energies computed at 228 configurations. The potential has a T-shaped global minimum and a local linear minimum. The global minimum occurs at R = 7.146 a(0), θ = 105.0° with energy of -270.73 cm(-1). Bound state energies up to J = 9 are calculated for three isotopomers (82)Kr-OCS, (84)Kr-OCS, and (86)Kr-OCS. Analysis of the vibrational wavefunctions and energies suggests the complex can exist in two isomeric forms: T-shaped and quasi-linear. The calculated transition frequencies and spectroscopic constants of the three isotopomers are in good agreement with the experimental values.
Pseudoscalar mesons with symmetric bound state vertex functions on the light front
Yabusaki, George H S; Paracha, M Ali; de Melo, J P B C; El-Bennich, Bruno
2015-01-01
We study the electromagnetic form factors, decay constants and charge radii of the pion and kaon within the framework of light-front field theory formalism where we use an ansatz for the quark-meson interaction bound-state function which is symmetric under exchange of quark and antiquark momentum. The above mentioned observables are evaluated for the $+$ component of the electromagnetic current, $J^+$, in the Breit frame. We also check the invariance of these observables in other frames, whereby both the valance and the non-valence contributions have to be taken into account, and study the sensitivity of the electromagnetic form factors and charge radius to the model's parameters; namely, the quark masses, $m_u=m_d$, $m_{\\bar s}$, and the regulator mass, $m_R$. It is found that after a fine tuning of the regulator mass, i.e. $m_R=0.6$ GeV, the model is suitable to fit the available experimental data within the theoretical uncertainties of both the pion and kaon.
Bound state structure and electromagnetic form factor beyond the ladder approximation
Gigante, V; Ydrefors, E; Gutierrez, C; Karmanov, V A; Frederico, T
2016-01-01
We investigate the response of the bound state structure of a two-boson system, within a Yukawa model with a scalar boson exchange, to the inclusion of the cross-ladder contribution to the ladder kernel of the Bethe-Salpeter equation. The equation is solved by means of the Nakanishi integral representation and light-front projection. The valence light-front wave function and the elastic electromagnetic form factor beyond the impulse approximation, with the inclusion of the two-body current, generated by the cross-ladder kernel, are computed. The valence wave function and electromagnetic form factor, considering both ladder and ladder plus cross-ladder kernels, are studied in detail. Their asymptotic forms are found to be quite independent of the inclusion of the cross-ladder kernel, for a given binding energy. The asymptotic decrease of form factor agrees with the counting rules. This analysis can be generalized to fermionic systems, with a wide application in the study of the meson structure.
Spectra of Lorentz-violating Dirac bound states in a cylindrical well
Xiao, Zhi
2016-12-01
In the presence of the Lorentz-violating bμ coefficient, the spectra of bound states for a Dirac particle in a cylindric well are changed. Compared to the Lorentz invariant (LI) spectrum, the Lorentz violation deviation becomes significant when eigenenergy E is sufficiently close to the critical values ±m , where m is the particle's mass. The detailed profile of the deviation depends on the observer Lorentz nature of bμ. We discussed three types of bμ configuration. When bμ=(0 ,0 ,0 ,bZ) is parallel to the well axis, the would be degenerate LI spectra split into two subspectra, reminiscent of the Zeeman splitting in the presence of a weak magnetic field. Depending on the relative sign of bZ accompanying mass m in the dispersion relation, the spectrum extends or shrinks in the allowed eigenenergy region. When bμ is a radial [bμ=(0 ,b cos ϕ ,b sin ϕ ,0 ) ] or purely timelike vector [bμ=(bT,0 →)], the spin-up and down components are coupled together, and there is no splitting. However, the monotonic increasing behavior of well depth V0 with the decrease of eigenenergy E is slightly changed when E is sufficiently close to -m .
Energy Technology Data Exchange (ETDEWEB)
Sturm, Sven
2012-09-06
This thesis describes the ultra-precise determination of the g-factor of the electron bound to hydrogenlike {sup 28}Si{sup 13+}. The experiment is based on the simultaneous determination of the cyclotron- and Larmor frequency of a single ion, which is stored in a triple Penning-trap setup. The continuous Stern-Gerlach effect is used to couple the spin of the bound electron to the motional frequencies of the ion via a magnetic bottle, which allows the non-destructive determination of the spin state. To this end, a highly sensitive, cryogenic detection system was developed, which allowed the direct, non-destructive detection of the eigenfrequencies with the required precision. The development of a novel, phase sensitive detection technique finally allowed the determination of the g-factor with a relative accuracy of 4 . 10{sup -11}, which was previously inconceivable. The comparison of the hereby determined value with the value predicted by quantumelectrodynamics (QED) allows the verification of the validity of this fundamental theory under the extreme conditions of the strong binding potential of a highly charged ion. The exact agreement of theory and experiment is an impressive demonstration of the exactness of QED. The experimental possibilities created in this work will allow in the near future not only further tests of theory, but also the determination of the mass of the electron with a precision that exceeds the current literature value by more than an order of magnitude.
Structure of charmed baryons studied by pionic decays
Nagahiro, Hideko; Hosaka, Atsushi; Oka, Makoto; Noumi, Hiroyuki
2016-01-01
We investigate the decays of the charmed baryons aiming at the systematic understanding of hadron internal structures based on the quark model by paying attention to heavy quark symmetry. We evaluate the decay widths from the one pion emission for the known excited states, \\Lambda_c^*(2595), \\Lambda_c^*(2625), \\Lambda_c^*(2765), \\Lambda_c^*(2880) and \\Lambda_c^*(2940), as well as for the ground states \\Sigma_c(2455) and \\Sigma_c^*(2520). The decay properties of the lower excited charmed baryons are well explained, and several important predictions for higher excited baryons are given. We find that the axial-vector type coupling of the pion to the light quarks is essential, which is expected from chiral symmetry, to reproduce the decay widths especially of the low lying \\Lambda_c^* baryons. We emphasize the importance of the branching ratios of \\Gamma(\\Sigma_c^*\\pi)/\\Gamma(\\Sigma_c\\pi) for the study of the nature of higher excited \\Lambda_c^* baryons.
Bound States of the Klein-Gordon and Dirac equations for potential V0 tanh2(r/d)
Institute of Scientific and Technical Information of China (English)
Qiang Wen-Chao
2004-01-01
The exact bound state wavefunctions and energy equations of Klein-Gordon and Dirac equations are given with equal scalar and vector potential s(r) = v(r) = V(r)/2 = V0 tanh2(r/d). The relation between the energy equation and that of relativistic harmonic is discussed.
Institute of Scientific and Technical Information of China (English)
Chen Gang; Chen Zi-Dong; Lou Zhi-Mei
2004-01-01
The exact bound state solutions of the Klein-Gordon equation and Dirac equation with scalar and vector pseudoharmonic oscillator potentials are obtained in this paper. Furthermore, we have used the supersymmetric quantum mechanics, shape invariance and alternative method to obtain the required results.
Does the Higgs mechanism favour electron-electron bound states in Maxwell-Chern-Simons $QED_{3}$?
Belich, H; Helayël-Neto, José A
2000-01-01
The low-energy electron-electron scattering potential is derived and discussed for the Maxwell-Chern-Simons model coupled to QED_3 with spontaneous symmetry breaking. One shows that the Higgs mechanism might favour electron-electron bound states.
Relativistic Bound States in 2+1 and 1+1 Dimensions in the Null-Plane
Pacheco-Bicudo-Cabral de Melo, J; Tomio, L; Frederico, T; Tomio, Lauro
1998-01-01
The Relativistic formulation of the three-boson model interacting via a zero-range two-body force in the null-plane is given in 2+1 and 1+1 space-time dimension. The bound state energy is calculed as function of the two-body boson binding energy.
Matviychuk, Oksana G.
2012-11-01
The paper deals with the state estimation problem for the linear control system containing impulsive control terms (or measures). The problem is studied here under uncertainty conditions when the initial system state is unknown but bounded, with given bound. It is assumed also that the system states should belong to the given ellipsoid in the state space. So the main problem of estimating the reachable set of the control system is studied here under more complicated assumption related to the case of state constraints. It is assumed additionally that impulsive controls in the dynamical system must belong to the intersection of a special cone with a generalized ellipsoid both taken in the space of functions of bounded variation. The last constraint is motivated by problems of impulsive control theory and by models from applied areas when not every direction of control impulses is acceptable in the system. We present here the state estimation algorithms that use the special structure of the control system and take into account additional restrictions on states and controls. The algorithms are based on ellipsoidal techniques for estimating the trajectory tubes of uncertain dynamical systems. Numerical simulation results related to proposed procedures are also given.
Institute of Scientific and Technical Information of China (English)
Gongming WEI
2008-01-01
A 2-coupled nonlinear Schr(o)dinger equations with bounded varying potentials and strongly attractive interactions is considered.When the attractive interaction is strong enough,the existence of a ground state for sufficiently small Planck constant is proved.As the Planck constant approaches zero,it is proved that one of the components concentrates at a minimum point of the ground state energy function which is defined in Section 4.
ABC effect and resonance structure in the double-pionic fusion to 3He
Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bergmann, F. S.; Berłowski, M.; Bhatt, H.; Bondar, A.; Büscher, M.; Calén, H.; Ciepał, I.; Clement, H.; Coderre, D.; Czerwiński, E.; Demmich, K.; Doroshkevich, E.; Engels, R.; Erven, A.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goslawski, P.; Goswami, A.; Grigoryev, K.; Gullström, C.-O.; Hauenstein, F.; Heijkenskjöld, L.; Hejny, V.; Höistad, B.; Hüsken, N.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kemmerling, G.; Khan, F. A.; Khoukaz, A.; Kirillov, D. A.; Kistryn, S.; Kleines, H.; Kłos, B.; Krzemień, W.; Kulessa, P.; Kupść, A.; Kuzmin, A.; Lalwani, K.; Lersch, D.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Mikirtychiants, M.; Morsch, H.-P.; Moskal, P.; Ohm, H.; Ozerianska, I.; Perez del Rio, E.; Piskunov, N. M.; Podkopał, P.; Prasuhn, D.; Pricking, A.; Pszczel, D.; Pysz, K.; Pyszniak, A.; Ritman, J.; Roy, A.; Rudy, Z.; Sawant, S.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Shwartz, B.; Siudak, R.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Stephan, E.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Täschner, A.; Trzciński, A.; Varma, R.; Wagner, G. J.; Wolke, M.; Wrońska, A.; Wüstner, P.; Wurm, P.; Yamamoto, A.; Yurev, L.; Zabierowski, J.; Zieliński, M. J.; Zink, A.; Złomańczuk, J.; Żuprański, P.; Żurek, M.; WASA-at-COSY Collaboration
2015-01-01
Exclusive and kinematically complete measurements of the double pionic fusion to 3He have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the π π -invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY (the cooler synchrotron at Forschungszentrum Jülich). Similar to the observations in the basic p n →d π0π0 reaction and in the d d →4He π0π0 reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. Differential cross sections are well described by the hypothesis of d* resonance formation during the reaction process in addition to the conventional t -channel Δ Δ mechanism. The deduced d* resonance width can be understood from collision broadening due to Fermi motion of the nucleons in initial and final nuclei.
Abashian-Booth-Crowe Effect in Basic Double-Pionic Fusion: A New Resonance?
Adlarson, P.; Adolph, C.; Augustyniak, W.; Baru, V.; Bashkanov, M.; Bednarski, T.; Bergmann, F. S.; Berłowski, M.; Bhatt, H.; Brinkmann, K.-T.; Büscher, M.; Calén, H.; Clement, H.; Coderre, D.; Czerwiński, E.; Doroshkevich, E.; Ekström, C.; Engels, R.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goslawski, P.; Grigoryev, K.; Grishina, V.; Gullström, C.-O.; Hampe, J.; Hanhart, C.; Heijkenskjöld, L.; Hejny, V.; Hinterberger, F.; Hodana, M.; Höistad, B.; Jacewicz, M.; Janusz, M.; Jany, A.; Jany, B. R.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kemmerling, G.; Khakimova, O.; Khoukaz, A.; Kistryn, S.; Klaja, J.; Kleines, H.; Kłos, B.; Kren, F.; Krzemień, W.; Kulessa, P.; Kullander, S.; Kupść, A.; Lalwani, K.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Mikirtychiants, M.; Moskal, P.; Morsch, H.-P.; Nandi, B. K.; Niedźwiecki, S.; Ohm, H.; Passfeld, A.; Pauly, C.; Perez Del Rio, E.; Petukhov, Y.; Piskunov, N.; Pluciński, P.; Podkopał, P.; Povtoreyko, A.; Prasuhn, D.; Pricking, A.; Pysz, K.; Rausmann, T.; Redmer, C. F.; Ritman, J.; Roy, A.; Ruber, R. J. M. Y.; Rudy, Z.; Sawant, S.; Schadmand, S.; Schmidt, A.; Schroeder, W.; Sefzick, T.; Serdyuk, V.; Shah, N.; Siemaszko, M.; Siudak, R.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Täschner, A.; Tolba, T.; Trzciński, A.; Varma, R.; Vlasov, P.; Wagner, G. J.; Węglorz, W.; Winnemöller, A.; Wirzba, A.; Wolke, M.; Wrońska, A.; Wüstner, P.; Wurm, P.; Yuan, X.; Yurev, L.; Zabierowski, J.; Zheng, C.; Zieliński, M. J.; Zipper, W.; Złomańczuk, J.; Żuprański, P.
2011-06-01
We report on an exclusive and kinematically complete high-statistics measurement of the basic double-pionic fusion reaction pn→dπ0π0 over the full energy region of the ABC effect, a pronounced low-mass enhancement in the ππ-invariant mass spectrum. The measurements, which cover also the transition region to the conventional t-channel ΔΔ process, were performed with the upgraded WASA detector setup at COSY. The data reveal the Abashian-Booth-Crowe effect to be uniquely correlated with a Lorentzian energy dependence in the integral cross section. The observables are consistent with a narrow resonance with m=2.37GeV, Γ≈70MeV and I(JP)=0(3+) in both pn and ΔΔ systems. Necessary further tests of the resonance interpretation are discussed.
Isospin Decomposition of the Basic Double-Pionic Fusion in the Region of the ABC Effect
Directory of Open Access Journals (Sweden)
Skorodko T.
2012-12-01
Full Text Available With a proton beam of Tp = 1.2 GeV incident on the deuterium pellet target of the WASA detector setup all three basic double-pionic fusion reactions have been measured simultaneously. By use of quasifree kinematics the energy range 2.3 GeV ≤ √s < 2.5 GeV could be covered, which just coincides with the energy region, where the ABC effect and its associated resonance structure has been observed. From the isospin decomposition we see that the resonance effect is solely in the isoscalar part of the reaction process, whereas the isovector part exhibits a monotonic smoothly rising energy dependence and no ABC effect.
Abashian-Booth-Crowe effect in basic double-pionic fusion: a new resonance?
Adlarson, P; Adolph, C; Augustyniak, W; Baru, V; Bashkanov, M; Bednarski, T; Bergmann, F S; Berłowski, M; Bhatt, H; Brinkmann, K-T; Büscher, M; Calén, H; Clement, H; Coderre, D; Czerwiński, E; Doroshkevich, E; Ekström, C; Engels, R; Erven, W; Eyrich, W; Fedorets, P; Föhl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Grigoryev, K; Grishina, V; Gullström, C-O; Hampe, J; Hanhart, C; Heijkenskjöld, L; Hejny, V; Hinterberger, F; Hodana, M; Höistad, B; Jacewicz, M; Janusz, M; Jany, A; Jany, B R; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khakimova, O; Khoukaz, A; Kistryn, S; Klaja, J; Kleines, H; Kłos, B; Kren, F; Krzemień, W; Kulessa, P; Kullander, S; Kupść, A; Lalwani, K; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Mariański, B; Mikirtychiants, M; Moskal, P; Morsch, H-P; Nandi, B K; Niedźwiecki, S; Ohm, H; Passfeld, A; Pauly, C; del Rio, E Perez; Petukhov, Y; Piskunov, N; Pluciński, P; Podkopał, P; Povtoreyko, A; Prasuhn, D; Pricking, A; Pysz, K; Rausmann, T; Redmer, C F; Ritman, J; Roy, A; Ruber, R J M Y; Rudy, Z; Sawant, S; Schadmand, S; Schmidt, A; Schroeder, W; Sefzick, T; Serdyuk, V; Shah, N; Siemaszko, M; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Sterzenbach, G; Stockhorst, H; Ströher, H; Szczurek, A; Täschner, A; Tolba, T; Trzciński, A; Varma, R; Vlasov, P; Wagner, G J; Węglorz, W; Winnemöller, A; Wirzba, A; Wolke, M; Wrońska, A; Wüstner, P; Wurm, P; Yuan, X; Yurev, L; Zabierowski, J; Zheng, C; Zieliński, M J; Zipper, W; Złomańczuk, J; Zuprański, P
2011-06-17
We report on an exclusive and kinematically complete high-statistics measurement of the basic double-pionic fusion reaction pn→dπ(0)π(0) over the full energy region of the ABC effect, a pronounced low-mass enhancement in the ππ-invariant mass spectrum. The measurements, which cover also the transition region to the conventional t-channel ΔΔ process, were performed with the upgraded WASA detector setup at COSY. The data reveal the Abashian-Booth-Crowe effect to be uniquely correlated with a Lorentzian energy dependence in the integral cross section. The observables are consistent with a narrow resonance with m=2.37 GeV, Γ≈70 MeV and I(J(P))=0(3(+)) in both pn and ΔΔ systems. Necessary further tests of the resonance interpretation are discussed.
Isospin Decomposition of the Basic Double-Pionic Fusion in the Region of the ABC Effect
Adlarson, P; Bardan, W; Bashkanov, M; Bednarski, T; Bergmann, F S; Berlowski, M; Bhatt, H; Büscher, M; Calen, H; Clement, H; Coderre, D; Czerwinski, E; Demmich, K; Doroshkevich, E; Engels, R; Erven, W; Eyrich, W; Fedorets, P; Föhl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Goswami, A; Grigoryev, K; Gullstrom, C -O; Hauenstein, F; Heijkenskjol, L; Hejny, V; Hinterberger, F; Hodana, M; Hoistad, B; Jany, A; Jany, B R; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khan, F A; Khoukaz, A; Kistryn, S; Klaja, J; Kleines, H; Klos, B; Krapp, M; Krzemien, W; Kulessa, P; Kupsc, A; Lalwani, K; Lersch, D; Li, L; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Marianski, B; Mikirtychiants, M; Morsch, H -P; Moskal, P; Nandi, B K; Niedzwiecki, S; Ohm, H; Ozerianska, I; del Rio, E Perez; Plucinski, P; Podkopal, P; Prasuhn, D; Pricking, A; Pszczel, D; Pysz, K; Pyszniak, A; Redmer, C F; Ritman, J; Roy, A; Rudy, Z; Sawant, S; Schadmand, S; Schmidt, A; Sefzick, T; Serdyuk, V; Shah, N; Siemaszko, M; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Stephan, E; Sterzenbach, G; Stockhorst, H; Ströher, H; Szczurek, A; Tolba, T; Trzcinski, A; Varma, R; Vlasov, P; Wagner, G J; Wkeglorz, W; Wolke, M; Wronska, A; Wüstner, P; Wurm, P; Yamamoto, A; Yuan, X; Yurev, L; Zabierowski, J; Zheng, C; Zielinski, M J; Zipper, W; Zlomanczuk, J; Zupranski, P; Zurek, M
2012-01-01
Exclusive and kinematically complete high-statistics measurements of the basic double pionic fusion reactions pn -> dpi0pi0, pn -> d pi+pi- and pp -> dpi+pi0 have been carried out simultaneously over the energy region of the ABC effect using the WASA detector setup at COSY. Whereas the isoscalar reaction part given by the dpi0pi0 channel exhibits the ABC effect, i.e. a low-mass enhancement in the pipi-invariant mass distribution, as well as the associated resonance structure in the total cross section, the isovector part given by the dpi+pi0 channel shows a smooth behavior consistent with the conventional t-channel Delta Delta process. The dpi+pi- data are very well reproduced by combining the data for isovector and isoscalar contributions, if the kinematical consequences of the isospin violation due to different masses for charged and neutral pions are taken into account.
Lacki, Brian C
2013-01-01
Equipartition arguments provide an easy way to find a characteristic scale for the magnetic field from radio emission, by assuming the energy densities in cosmic rays and magnetic fields are the same. Yet most of the cosmic ray content in star-forming galaxies is in protons, which are invisible in radio emission. Therefore, the argument needs assumptions about the proton spectrum, typically that of a constant proton/electron ratio. In some environments, particularly starburst galaxies, the reasoning behind these assumptions does not necessarily hold: secondary pionic positrons and electrons may be responsible for most of the radio emission, and strong energy losses can alter the proton/electron ratio. We derive an equipartition expression that should work in a hadronic loss-dominated environment like starburst galaxies. Surprisingly, despite the radically different assumptions from the classical equipartition formula, numerically the results for starburst magnetic fields are similar. We explain this fortuitou...
ABC Effect and Resonance Structure in the Double-Pionic Fusion to $^3$He
Adlarson, P; Bardan, W; Bashkanov, M; Bergmann, F S; Berłowski, M; Bhatt, H; Bondar, A; Büscher, M; Calén, H; Ciepał, I; Clement, H; Coderre, D; Czerwiński, E; Demmich, K; Doroshkevich, E; Engels, R; Erven, A; Erven, W; Eyrich, W; Fedorets, P; Föhl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Goswami, A; Grigoryev, K; Gullström, C --O; Hauenstein, F; Heijkenskjöld, L; Hejny, V; Höistad, B; Hüsken, N; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khan, F A; Khoukaz, A; Kirillov, D A; Kistryn, S; Kleines, H; Kłos, B; Krzemień, W; Kulessa, P; Kupść, A; Kuzmin, A; Lalwani, K; Lersch, D; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Mariański, B; Mikirtychiants, M; Morsch, H -P; Moskal, P; Ohm, H; Ozerianska, I; del Rio, E Perez; Piskunov, N M; Podkopał, P; Prasuhn, D; Pricking, A; Pszczel, D; Pysz, K; Pyszniak, A; Ritman, J; Roy, A; Rudy, Z; Sawant, S; Schadmand, S; Sefzick, T; Serdyuk, V; Shwartz, B; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Stephan, E; Sterzenbach, G; Stockhorst, H; Ströher, H; Szczurek, A; Täschner, A; Trzciński, A; Varma, R; Wagner, G J; Wolke, M; Wrońska, A; Wüstner, P; Wurm, P; Yamamoto, A; Yurev, L; Zabierowski, J; Zieliński, M J; Zink, A; Złomańczuk, J; Żuprański, P; Żurek, M
2014-01-01
Exclusive and kinematically complete measurements of the double pionic fusion to $^3$He have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the $\\pi\\pi$-invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY. Similar to the observations in the basic $pn \\to d \\pi^0\\pi^0$ reaction and in the $dd \\to ^4$He$\\pi^0\\pi^0$ reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. Differential cross sections are well described by the hypothesis of $d^*$ resonance formation during the reaction process in addition to the conventional $t$-channel $\\Delta\\Delta$ mechanism. The deduced $d^*$ resonance width can be understood from collision broadening due to Fermi motion of the nucleons in initial and final nuclei.
On the nonlocal Fisher-KPP equation: steady states, spreading speed and global bounds
Hamel, François; Ryzhik, Lenya
2014-11-01
We consider the Fisher-KPP (for Kolmogorov-Petrovsky-Piskunov) equation with a nonlocal interaction term. We establish a condition on the interaction that allows for existence of non-constant periodic solutions, and prove uniform upper bounds for the solutions of the Cauchy problem, as well as upper and lower bounds on the spreading rate of the solutions with compactly supported initial data.
Sulfur Atom in its Bound State Is a Unique Element Involved in Physiological Functions in Mammals
Directory of Open Access Journals (Sweden)
Shin Koike
2016-12-01
Full Text Available It was in the 1950s that the term polysulfide or persulfide was introduced in biological studies. The unfamiliar term “sulfane sulfur” sometimes appeared in papers published in the 1970s, and was defined in the review article by Westley in 1983. In the article, sulfane sulfur is described as sulfur atoms that are covalently bound only with sulfur atoms, and as this explanation was somewhat difficult to comprehend, it was not generally accepted. Thus, in the early 1990s, we redefined these sulfur species as “bound sulfur”, which easily converts to hydrogen sulfide on reduction with a thiol reducing agent. In other words, bound sulfur refers to a sulfur atom that exists in a zero to divalent form (0 to −2. The first part of this review focuses on the fluorescent derivatization HPLC method—which we developed for measurement of bound sulfur—and explains the distribution of bound sulfur and the hydrogen sulfide-producing ability of various tissues, as clarified by this method. Next, we discuss diverse physiological functions and involvement of polysulfide, a typical type of bound sulfur, in the redox regulation system. Additionally, we also address its possible physiological role in the central nervous system, based on its action of scavenging reactive carbonyl compounds.
Structural characterization of two metastable ATP-bound states of P-glycoprotein.
Directory of Open Access Journals (Sweden)
Megan L O'Mara
Full Text Available ATP Binding Cassette (ABC transporters couple the binding and hydrolysis of ATP to the transport of substrate molecules across the membrane. The mechanism by which ATP binding and/or hydrolysis drives the conformational changes associated with substrate transport has not yet been characterized fully. Here, changes in the conformation of the ABC export protein P-glycoprotein on ATP binding are examined in a series of molecular dynamics simulations. When one molecule of ATP is placed at the ATP binding site associated with each of the two nucleotide binding domains (NBDs, the membrane-embedded P-glycoprotein crystal structure adopts two distinct metastable conformations. In one, each ATP molecule interacts primarily with the Walker A motif of the corresponding NBD. In the other, the ATP molecules interacts with both Walker A motif of one NBD and the Signature motif of the opposite NBD inducing the partial dimerization of the NBDs. This interaction is more extensive in one of the two ATP binding site, leading to an asymmetric structure. The overall conformation of the transmembrane domains is not altered in either of these metastable states, indicating that the conformational changes associated with ATP binding observed in the simulations in the absence of substrate do not lead to the outward-facing conformation and thus would be insufficient in themselves to drive transport. Nevertheless, the metastable intermediate ATP-bound conformations observed are compatible with a wide range of experimental cross-linking data demonstrating the simulations do capture physiologically important conformations. Analysis of the interaction between ATP and its cofactor Mg(2+ with each NBD indicates that the coordination of ATP and Mg(2+ differs between the two NBDs. The role structural asymmetry may play in ATP binding and hydrolysis is discussed. Furthermore, we demonstrate that our results are not heavily influenced by the crystal structure chosen for initiation
Quantum Transport through a Triple Quantum Dot System in the Presence of Majorana Bound States
Jiang, Zhao-Tan; Cao, Zhi-Yuan; Zhong, Cheng-Cheng
2016-05-01
We study the electron transport through a special quantum-dot (QD) structure composed of three QDs and two Majorana bound states (MBSs) using the nonequilibrium Green's function technique. This QD-MBS ring structure includes two channels with the two coupled MBSs being Channel 1 and one QD being Channel 2, and three types of transport processes such as the electron transmission (ET), the Andreev reflection (AR), and the crossed Andreev reflection (CAR). By comparing the ET, AR, and CAR processes through Channels 1 and 2, we make a systematic study on the transport properties of the QD-MBS ring. It is shown that there appear two kinds of characteristic transport patterns for Channels 1 and 2, as well as the interplay between the two patterns. Of particular interest is that there exists an AR-assisted ET process in Channel 2, which is different from that in Channel 1. Thus a clear “X” pattern due to the ET and AR processes appears in the ET, AR, and CAR transmission coefficients. Moreover, we study how Channel 2 affects the three transport processes when Channel 1 is tuned in the ET and CAR regimes. It is shown that the transport properties of the ET, AR and CAR processes can be adjusted by tuning the energy level of the QD embedded in Channel 2. We believe this research should be a helpful reference for understanding the transport properties in the QD-MBS coupled systems. Supported by National Natural Science Foundation of China under Grant No. 11274040, and by the Program for New Century Excellent Talents in University under Grant No. NCET-08-0044
The ρ(ω/B*(B system and bound states in the unitary local Hidden Gauge approach
Directory of Open Access Journals (Sweden)
Fernandez-Soler P.
2016-01-01
Full Text Available In this work, we study systems composed of a ρ/ω and B* meson pair. We find three bound states in isospin, spin-parity channels (1/2, 0+, (1/2, 1+ and (1/2, 2+. The state with J = 2 can be a good candidate for the B*2(5747. We also study the ρB system, and a bound state with mass 5728 MeV and width around 20 MeV is obtained, which can be identified with the B1(5721 resonance. In the case of I = 3/2, one obtains repulsion and thus, no exotic (molecular mesons in this sector are generated in the approach.
In-medium bound-state formation and inhomogeneous condensation in Fermi gases in a hard-wall box
Roscher, Dietrich
2016-01-01
The formation of bosonic bound states underlies the formation of a superfluid ground state in the many-body phase diagram of ultracold Fermi gases. We study bound-state formation in a spin- and mass-imbalanced ultracold Fermi gas confined in a box with hard-wall boundary conditions. Because of the presence of finite Fermi spheres, the center-of-mass momentum of the potentially formed bound states can be finite, depending on the parameters controlling mass and spin imbalance as well as the coupling strength. We exploit this observation to estimate the potential location of inhomogeneous phases in the many-body phase diagram as a function of spin- and mass imbalance as well as the box size. Our results suggest that a hard-wall box does not alter substantially the many-body phase diagram calculated in the thermodynamic limit. Therefore, such a box may serve as an ideal trap potential to bring experiment and theory closely together and facilitate the search for exotic inhomogeneous ground states.
Obreshkov, Boyan
2016-01-01
The collision-induced shift and broadening of selected dipole transition lines of pionic helium in gaseous helium at low temperatures up to $T=12$ K and pressure up to a few bar are calculated within variable phase function approach. We predict blue shift of the resonance frequencies of the $(n,l)=(16,15) \\rightarrow (16,14) $ and $(16,15) \\rightarrow (17,14)$ unfavored transitions and red shift for the favored transition $(17,16) \\rightarrow (16,15)$. The result may be helpful in reducing the systematic error in proposed future experiments for determination of the negatively charged pion mass from laser spectroscopy of metastable pionic helium atoms.
Huang, Dao-Ling; Liu, Hong-Tao; Dau, Phuong Diem; Wang, Lai-Sheng
2014-06-01
High-resolution vibrational spectroscopy of transient species is important for determining their molecular structures and understanding their chemical reactivity. However, the low abundance and high reactivity of molecular radicals pose major challenges to conventional absorption spectroscopic methods. The observation of dipole-bound states (DBS) in anions extend autodetachment spectroscopy to molecular anions whose corresponding neutral radicals possess a large enough dipole moment (>2.5 D).1,2 However, due to the difficulty of assigning the congested spectra at room temperature, there have been only a limited number of autodetachment spectra via DBS reported. Recently, we have built an improved version of a cold trap3 coupled with high-resolution photoelectron imaging.4 The first observation of mode-specific auotodetachment of DBS of cold phenoxide have shown that not only vibrational hot bands were completely suppressed, but also rotational profile was observed.5 The vibrational frequencies of the DBS were found to be the same as those of the neutral radical, suggesting that vibrational structures of dipolar radicals can be probed via DBS.5 More significantly, the DBS resonances allowed a number of vibrational modes with very weak Frank-Condon factors to be "lightened" up via vibrational autodetachment.5 Recently, our first high-resolution vibrational spectroscopy of the dehydrogenated uracil radical, with partial rotational resolution, via autodetachment from DBS of cold deprotonated uracil anions have been reported.6 Rich vibrational information is obtained for this important radical species. The resolved rotational profiles also allow us to characterize the rotational temperature of the trapped anions for the first time.6 1 K. R. Lykke, D. M. Neumark, T. Andersen, V. J. Trapa, and W. C. Lineberger, J. Chem. Phys. 87, 6842 (1987). 2 D. M. Wetzel, and J. I. Brauman, J. Chem. Phys. 90, 68 (1989). 3 P. D. Dau, H. T. Liu, D. L. Huang, and L. S. Wang, J. Chem. Phys
Derivation of a Closed Expression of the B-S Interaction Kernel for Quark-Antiquark Bound States
Institute of Scientific and Technical Information of China (English)
SU Jun-Chen
2002-01-01
The interaction kernel in the Bethe-Salpeter (B-S) equation for quark-antiquark bound states is derivedfrom B-S equations satisfied by the quark-antiquark four-point Green's function. The latter equations are establishedbased on the equations of motion obeyed by the quark and antiquark propagators, the four-point Green's function andsome other kinds of Green's functions, which follow directly from the QCD generating functional. The derived B-Skernel is given by a closed and explicit expression which contains only a few types of Green's functions. This expressionis not only convenient for perturbative calculations, but also applicable for nonperturbative investigations. Since thekernel contains all the interactions taking place in the quark-antiquark bound states, it actually appears to be the mostsuitable starting point of studying the QCD nonperturbative effect and quark confinement.
Energy of the low-lying bound S-states of exotic two-muon three-body systems
Khan, Md Abdul
2014-01-01
Energies of the low-lying bound S-states (L=0) of exotic three-body systems, consisting a nuclear core of charge +Ze (Z being atomic number of the core) and two negatively charged valence muons, have been calculated by hyperspherical harmonics expansion method (HHEM). The three-body Schr\\H{o}dinger equation is solved assuming purely Coulomb interaction among the binary pairs of the three-body systems X$^{Z+}\\mu^-\\mu^-$ for Z=1 to 54. Convergence pattern of the energies have been checked with respect to the increasing number of partial waves $K_{max}$. For available computer facilities, calculations are feasible up to $K_{max}=28$ partial waves, however, calculation for still higher partial waves have been achieved through an appropriate extrapolation scheme. The dependence of bound state energies has been checked against increasing nuclear charge Z and finally, the calculated energies have been compared with the ones of the literature.
Bound states of Klein-Gordon equation for double ring-shaped oscillator scalar and vector potentials
Institute of Scientific and Technical Information of China (English)
Lu Fa-Lin; Chen Chang-Yuan; Sun Dong-Sheng
2005-01-01
In Spherical polar coordinates, double ring-shaped oscillator potentials have supersymmetry and shape invariance for θ and τ coordinates. Exact bound state solutions of Klein-gordon equation with equal double ring-shaped oscillator scalar and vector potentials are obtained. The normalized angular wavefunction expressed in terms of Jacobi polynomials and the normalized radial wavefunction expressed in terms of the Laguerre polynomials are presented. Energy spectrum equations are obtained.
Fujioka, H; Benlliure, J; Brinkmann, K -T; Friedrich, S; Geissel, H; Gellanki, J; Guo, C; Gutz, E; Haettner, E; Harakeh, M N; Hayano, R S; Higashi, Y; Hirenzaki, S; Hornung, C; Igarashi, Y; Ikeno, N; Itahashi, K; Iwasaki, M; Jido, D; Kalantar-Nayestanaki, N; Kanungo, R; Knoebel, R; Kurz, N; Metag, V; Mukha, I; Nagae, T; Nagahiro, H; Nanova, M; Nishi, T; Ong, H J; Pietri, S; Prochazka, A; Rappold, C; Reiter, M P; Rodríguez-Sánchez, J L; Scheidenberger, C; Simon, H; Sitar, B; Strmen, P; Sun, B; Suzuki, K; Szarka, I; Takechi, M; Tanaka, Y K; Tanihata, I; Terashima, S; Watanabe, Y N; Weick, H; Widmann, E; Winfield, J S; Xu, X; Yamakami, H; Zhao, J
2015-01-01
The possible existence of \\eta'-nucleus bound states has been put forward through theoretical and experimental studies. It is strongly related to the \\eta' mass at finite density, which is expected to be reduced because of the interplay between the $U_A(1)$ anomaly and partial restoration of chiral symmetry. The investigation of the C(p,d) reaction at GSI and FAIR, as well as an overview of the experimental program at GSI and future plans at FAIR are discussed.
(p,q)-Five Brane and (p,q)-String Solutions, their Bound State and its Near Horizon Limit
Kluson, J
2016-01-01
We determine (p,q)-string and (p,q)-five brane solutions of type IIB supergravity using SL(2,Z)-symmetry of the full type IIB superstring theory. We also determine SL(2,Z)-transformed solution corresponding to the bound state of NS5-branes and fundamental strings. Then we analyze its near horizon limit and we show that it leads to the AdS(3)xS(3) with mixed fluxes.
Energy Technology Data Exchange (ETDEWEB)
Suparmi, A., E-mail: suparmiuns@gmail.com; Cari, C., E-mail: suparmiuns@gmail.com [Physics Department, Post Graduate Study, Sebelas Maret University (Indonesia); Angraini, L. M. [Physics Department, Mataram University (Indonesia)
2014-09-30
The bound state solutions of Dirac equation for Hulthen and trigonometric Rosen Morse non-central potential are obtained using finite Romanovski polynomials. The approximate relativistic energy spectrum and the radial wave functions which are given in terms of Romanovski polynomials are obtained from solution of radial Dirac equation. The angular wave functions and the orbital quantum number are found from angular Dirac equation solution. In non-relativistic limit, the relativistic energy spectrum reduces into non-relativistic energy.
Simple mass estimates for resonance(s) being 6 top + 6 antitop bound states and combinations thereof
Nielsen, H. B.
2016-11-01
We have long speculated,2,12,50-62 that 6 top + 6 antitop quarks due to the relatively large size of the top-Yukawa coupling would bind exceptionally strongly by mainly Higgs exchange. Here we present a surprisingly simple “calculation” of the mass of this speculated bound state. Even a possible resonance in scattering of two such bound states is speculated. For the “calculation” of the masses it is crucial to assume, that our since long speculated principle “multiple point principle,”5-18 is true. This principle says: there are several vacua all having almost zero energy density. Further, we make an approximation of the Higgs Yukawa potential essentially replacing the exponential in it by a step-function. The new result means that there are now two independent calls for our bound state having the mass around 750 GeV required by our “new law of nature” the Multiple Point Principle. It should be remarked that in our picture there is no new physics in the sense of new fundamental particles, but the “multiple point principle” is new in the sense of being not yet accepted. Further, we get the same mass within uncertainties as earlier2 but now from a completely different assumption, except for being from our “multiple point principle.” But the two masses are gotten from using different (speculative) vacua occurring in the pure Standard Model.
Institute of Scientific and Technical Information of China (English)
Lin Feng; Zhang Wei; Zhao Ze-Yu; Cong Shu-Lin
2012-01-01
The photoassociation dynamics of ultracold lithium atoms controlled by a cut-off pulse has been investigated theoretically by solving numerically the time-dependent Schr(o)dinger equation using the mapped Fourier grid method.The frequency components of the laser pulse close to the atomic resonance are partly cut off.Compared with the typical Gauss-type pulses,the cut-off pulse is helpful to suppress efficiently the weakly bound states and prepare the associated molecules in the lower vibrational states.Especially,the dependence of photoassociation probability on the cut-off position of the laser pulse is explored.
Channel Capacity Bounds in the Presence of Quantized Channel State Information
Directory of Open Access Journals (Sweden)
Makki Behrooz
2010-01-01
Full Text Available The goal of this paper is to investigate the effect of channel side information on increasing the achievable rates of continuous power-limited non-Gaussian channels. We focus on the case where (1 there is imperfect channel quality information available to the transmitter and the receiver and (2 while the channel gain is continuously varying, there are few cross-region changes, and the noise characteristics remain in each detection region for a long time. The results are presented for two scenarios, namely, reliable and unreliable region detection. Considering short- and long-term power constraints, the capacity bounds are found for log-normal and two different Nakagami-based channel distributions, and for both Max-Lloyd and equal probability quantization approaches. Then, the optimal gain partitioning approach, maximizing the achievable rates, is determined. Finally, general equations for the channel capacity bounds and optimal channel partitioning in the case of unreliable region detection are presented. Interestingly, the results show that, for high SNR's, it is possible to determine a power-independent optimal gain partitioning approach maximizing the capacity lower bound which, in both scenarios, is identical for both short- and long-term power constraints.
Huang, Dao-Ling; Zhu, Guo-Zhu; Wang, Lai-Sheng
2016-06-01
Deprotonated thymine can exist in two different forms, depending on which of its two N sites is deprotonated: N1[T-H]^- or N3[T-H]^-. Here we report a photodetachment study of the N1[T-H]^- isomer cooled in a cryogenic ion trap and the observation of an excited dipole-bound state. Eighteen vibrational levels of the dipole-bound state are observed, and its vibrational ground state is found to be 238 ± 5 wn below the detachment threshold of N1[T-H]^-. The electron affinity of the deprotonated thymine radical (N1[T-H]^.) is measured accruately to be 26 322 ± 5 wn (3.2635 ± 0.0006 eV). By tuning the detachment laser to the sixteen vibrational levels of the dipole-bound state that are above the detachment threshold, highly non-Franck-Condon resonant-enhanced photoelectron spectra are obtained due to state- and mode-selective vibrational autodetachment. Much richer vibrational information is obtained for the deprotonated thymine radical from the photodetachment and resonant-enhanced photoelectron spectroscopy. Eleven fundamental vibrational frequencies in the low-frequency regime are obtained for the N1[T-H]^. radical, including the two lowest-frequency internal rotational modes of the methyl group at 70 ± 8 wn and 92 ± 5 wn. D. L. Huang, H. T. Liu, C. G. Ning, G. Z. Zhu and L. S. Wang, Chem. Sci., 6, 3129-3138 (2015)
Lowest Q^{2} Measurement of the γ*p→ Δ Reaction: Probing the Pionic Contribution
Energy Technology Data Exchange (ETDEWEB)
Stave, Sean C. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
2006-06-01
The first excited state of the proton, the Delat, can be reached through a magnetic dipole spin flip of one of the quarks (M1) or through electric and Coulomb quadrupole terms (E2 and C2) which indicate a deviation from spherical symmetry. The quark models using the color hyperfine interaction underestimate the size of the quadrupole terms by more than an order of magnitude. Models using the pion cloud do a much better job of describing the data. This is expected due to the spontaneous breaking of chiral symmetry which leads to a cloud of virtual p wave pions which introduce the non-spherical amplitudes. The data presented in this work fill gaps in the low Q², long distance region where the pion cloud is expected to dominate and to produce significant Q2 variation. The p(e¯, ép)π° reaction was measured in the Δ region at Q² = 0.060 (GeV/c)², the lowest Q² to date for pion electroproduction, utilizing out-of-plane magnetic spectrometers at the Mainz Microtron in Germany. This work reports results for the dominant transition magnetic dipole amplitude and the quadrupole to dipole ratios obtained from fitting the new data with models using a three parameter, resonant multipole fit: M³/²1+ = (40.33 +- 0.63stat+syst +-model)(10-³/mπ+), E2/M1=Re(E³/²1+M³/²1+) = (-2.28+- 0.29stat+syst +- 0.20model)%, and C2/M1 =Re(S³/²1+/M³/²1+) poles disagree with predictions of the quark models but are in reasonable agreement with a chiral extrapolation of lattice QCD, chiral effective field theory and dynamical model results confirming the dominance and general Q² variation of the long range pionic contribution. While there is qualitative agreement with the models, there is no quantitative agreement thus indicating the need for further improvement of the models.
Quasiparticle Scattering off Defects and Possible Bound States in Charge-Ordered YBa2 Cu3 Oy
Zhou, R.; Hirata, M.; Wu, T.; Vinograd, I.; Mayaffre, H.; Krämer, S.; Horvatić, M.; Berthier, C.; Reyes, A. P.; Kuhns, P. L.; Liang, R.; Hardy, W. N.; Bonn, D. A.; Julien, M.-H.
2017-01-01
We report the NMR observation of a skewed distribution of 17O Knight shifts when a magnetic field quenches superconductivity and induces long-range charge-density-wave (CDW) order in YBa2Cu3Oy . This distribution is explained by an inhomogeneous pattern of the local density of states N (EF) arising from quasiparticle scattering off, yet unidentified, defects in the CDW state. We argue that the effect is most likely related to the formation of quasiparticle bound states, as is known to occur, under specific circumstances, in some metals and superconductors (but not in the CDW state, in general, except for very few cases in 1D materials). These observations should provide insight into the microscopic nature of the CDW, especially regarding the reconstructed band structure and the sensitivity to disorder.
Unified theory of bound and scattering molecular Rydberg states as quantum maps
Dietz, Barbara; Lombardi, Maurice; Seligman, Thomas H.
2004-08-01
Using a representation of multichannel quantum defect theory in terms of a quantum Poincaré map for bound Rydberg molecules, we apply Jung's scattering map to derive a generalized quantum map, that includes the continuum. We show that this representation not only simplifies the understanding of the method, but moreover produces considerable numerical advantages. Finally we show under what circumstances the usual semi-classical approximations yield satisfactory results. In particular we see that singularities that cause problems in semi-classics are irrelevant to the quantum map.
Irie, Hiroshi; Todt, Clemens; Kumada, Norio; Harada, Yuichi; Sugiyama, Hiroki; Akazaki, Tatsushi; Muraki, Koji
2016-10-01
We study coherent transport and bound state formation of Bogoliubov quasiparticles in a high-mobility I n0.75G a0.25As two-dimensional electron gas (2DEG) coupled to a superconducting Nb electrode by means of a quantum point contact (QPC) as a tunable single-mode probe. Below the superconducting critical temperature of Nb, the QPC shows a single-channel conductance greater than the conductance quantum 2 e2/h at zero bias, which indicates the presence of Andreev-reflected quasiparticles, time-reversed states of the injected electron, returning back through the QPC. The marked sensitivity of the conductance enhancement to voltage bias and perpendicular magnetic field suggests a mechanism analogous to reflectionless tunneling—a hallmark of phase-coherent transport, with the boundary of the 2DEG cavity playing the role of scatterers. When the QPC transmission is reduced to the tunneling regime, the differential conductance vs bias voltage probes the single-particle density of states in the proximity area. Measured conductance spectra show a double peak within the superconducting gap of Nb, demonstrating the formation of Andreev bound states in the 2DEG. Both of these results, obtained in the open and closed geometries, underpin the coherent nature of quasiparticles, i.e., phase-coherent Andreev reflection at the InGaAs/Nb interface and coherent propagation in the ballistic 2DEG.
Isospin decomposition of the basic double-pionic fusion in the region of the ABC effect
Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bednarski, T.; Bergmann, F. S.; Berłowski, M.; Bhatt, H.; Büscher, M.; Calén, H.; Clement, H.; Coderre, D.; Czerwiński, E.; Demmich, K.; Doroshkevich, E.; Engels, R.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goslawski, P.; Goswami, A.; Grigoryev, K.; Gullström, C.-O.; Hauenstein, F.; Heijkenskjöld, L.; Hejny, V.; Hinterberger, F.; Hodana, M.; Höistad, B.; Jany, A.; Jany, B. R.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kemmerling, G.; Khan, F. A.; Khoukaz, A.; Kistryn, S.; Klaja, J.; Kleines, H.; Kłos, B.; Krapp, M.; Krzemień, W.; Kulessa, P.; Kupść, A.; Lalwani, K.; Lersch, D.; Li, L.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Mikirtychiants, M.; Morsch, H.-P.; Moskal, P.; Nandi, B. K.; Niedźwiecki, S.; Ohm, H.; Ozerianska, I.; Perez del Rio, E.; Pluciński, P.; Podkopał, P.; Prasuhn, D.; Pricking, A.; Pszczel, D.; Pysz, K.; Pyszniak, A.; Redmer, C. F.; Ritman, J.; Roy, A.; Rudy, Z.; Sawant, S.; Schadmand, S.; Schmidt, A.; Sefzick, T.; Serdyuk, V.; Shah, N.; Siemaszko, M.; Siudak, R.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Stephan, E.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Tolba, T.; Trzciński, A.; Varma, R.; Vlasov, P.; Wagner, G. J.; Węglorz, W.; Wolke, M.; Wrońska, A.; Wüstner, P.; Wurm, P.; Yamamoto, A.; Yuan, X.; Yurev, L.; Zabierowski, J.; Zheng, C.; Zieliński, M. J.; Zipper, W.; Złomańczuk, J.; Żuprański, P.; Żurek, M.
2013-04-01
Exclusive and kinematically complete high-statistics measurements of the basic double-pionic fusion reactions pn → dπ0π0, pn → dπ+π- and pp → dπ+π0 have been carried out simultaneously over the energy region of the ABC effect using the WASA detector setup at COSY. Whereas the isoscalar reaction part given by the dπ0π0 channel exhibits the ABC effect, i.e. a low-mass enhancement in the ππ-invariant mass distribution, as well as the associated resonance structure in the total cross section, the isovector part given by the dπ+π0 channel shows a smooth behavior consistent with the conventional t-channel ΔΔ process. The dπ+π- data are very well reproduced by combining the data for isovector and isoscalar contributions, if the kinematical consequences of the isospin violation due to different masses for charged and neutral pions are taken into account.
Abashian-Booth-Crowe resonance structure in the double pionic fusion to 4He
Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bednarski, T.; Bergmann, F. S.; Berłowski, M.; Bhatt, H.; Brinkmann, K.-T.; Büscher, M.; Calén, H.; Clement, H.; Coderre, D.; Czerwiński, E.; Demmich, K.; Doroshkevich, E.; Engels, R.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goslawski, P.; Grigoryev, K.; Gullström, C.-O.; Hauenstein, F.; Heijkenskjöld, L.; Hejny, V.; Hinterberger, F.; Hodana, M.; Höistad, B.; Husmann, C.; Jany, A.; Jany, B. R.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kemmerling, G.; Khan, F. A.; Khoukaz, A.; Kistryn, S.; Klaja, J.; Kleines, H.; Kłos, B.; Krzemień, W.; Kulessa, P.; Kupść, A.; Lalwani, K.; Lersch, D.; Li, L.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Mikirtychiants, M.; Morsch, H.-P.; Moskal, P.; Nandi, B. K.; Niedźwiecki, S.; Ohm, H.; Ozerianska, I.; Pauly, C.; Perez del Rio, E.; Petukhov, Y.; Pluciński, P.; Podkopał, P.; Prasuhn, D.; Pricking, A.; Pszczel, D.; Pysz, K.; Pyszniak, A.; Redmer, C. F.; Ritman, J.; Roy, A.; Rudy, Z.; Sawant, S.; Schadmand, S.; Schmidt, A.; Serdyuk, V.; Shah, N.; Siudak, R.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Tolba, T.; Trzciński, A.; Varma, R.; Vlasov, P.; Wagner, G. J.; Węglorz, W.; Wolke, M.; Wrońska, A.; Wüstner, P.; Wurm, P.; Yamamoto, A.; Yuan, X.; Yurev, L.; Zabierowski, J.; Zheng, C.; Zieliński, M. J.; Zipper, W.; Złomańczuk, J.; Żuprański, P.
2012-09-01
Exclusive and kinematically complete high-statistics measurements of the double pionic fusion reaction dd→4Heπ0π0 have been performed in the energy range 0.8-1.4 GeV covering thus the region of the Abashian-Booth-Crowe effect, which denotes a pronounced low-mass enhancement in the ππ invariant mass spectrum. The experiments were carried out with the WASA detector setup at the cooler synchrotron at Forshungszentrum Julich GmbH. Similar to the observation in the basic pn→dπ0π0 reaction, the data reveal a correlation between the ABC effect and a resonancelike energy dependence in the total cross section. The maximum occurs at m=2.37 GeV + 2mN, i.e., at the same position as in the basic reaction. The observed resonance width Γ≈160 MeV can be understood from broadening due to Fermi motion of the nucleons in initial and final nuclei together with collision damping. Differential cross sections are described equally well by the hypothesis of a pn resonance formation during the reaction process.
ABC Resonance Structure in the Double-Pionic Fusion to 4He
Adlarson, P; Bardan, W; Bashkanov, M; Bednarski, T; Bergmann, F S; Berlowski, M; Bhatt, H; Brinkmann, K T; Buescher, M; Calen, H; Clement, H; Coderre, D; Czerwinski, E; Demmich, K; Doroshkevich, E; Engels, R; Erven, W; Eyrich, W; Fedorets, P; Foehl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Grigoryev, K; Gullstroem, C O; Hauenstein, F; Heijkenskjold, L; Hejny, V; Hinterberger, F; Hodana, M; Hoistad, B; Husmann, C; Jany, A; Jany, B R; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khan, F A; Khoukaz, A; Kistryn, S; Klaja, J; Kleines, H; Klos, B; Krzemien, W; Kulessa, P; Kupsc, A; Lalwani, K; Lersch, D; Li, L; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Marianski, B; Mikirtychiants, M; Morsch, H P; Moskal, P; Nandi, B K; Niedzwiecki, S; Ohm, H; Ozerianska, I; Pauly, C; del Rio, E Perez; Petukhov, Y; Plucinski, P; Podkopal, P; Prasuhn, D; Pricking, A; Pszczel, D; Pysz, K; Pyszniak, A; Redmer, C F; Ritman, J; Roy, A; Rudy, Z; Sawant, S; Schadmand, S; Schmidt, A; Serdyuk, V; Shah, N; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Sterzenbach, G; Stockhorst, H; Stroeher, H; Szczurek, A; Tolba, T; Trzcinski, A; Varma, R; Vlasov, P; Wagner, G J; Wkeglorz, W; Wolke, M; Wronska, A; Wuestner, P; Wurm, P; Yamamoto, A; Yuan, X; Yurev, L; Zabierowski, J; Zheng, C; Zielinski, M J; Zipper, W; Zlomanczuk, J; Zupranski, P
2012-01-01
Exclusive and kinematically complete high-statistics measurements of the double pionic fusion reaction $dd \\to ^4$He$\\pi^0\\pi^0$ have been performed in the energy range 0.8 - 1.4 GeV covering thus the region of the ABC effect, which denotes a pronounced low-mass enhancement in the $\\pi\\pi$-invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY. Similar to the observation in the basic $pn \\to d \\pi^0\\pi^0$ reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. The maximum occurs at m=2.37 GeV + 2$m_N$, i.e. at the same position as in the basic reaction. The observed resonance width $\\Gamma \\approx$ 160 MeV can be understood from broadening due to Fermi motion of the nucleons in initial and final nuclei together with collision damping. Differential cross sections are described equally well by the hypothesis of a $pn$ resonance formation during the reaction process.
Determination of the effective quadrupole moment in $^{181}$Ta with pionic x-rays
Beetz, R; Fransson, K; Konijn, J; Panman, J; Tauscher, Ludwig; Tibell, G
1978-01-01
From the hyperfine splitting of the 5g to 4f and the 6g to 4f pionic X-rays in /sup 181/Ta, an effective quadrupole moment of Q/sub eff /=3.58+or-0.03 b was determined. The strong interaction monopole shift epsilon /sub 0/ and the width Gamma /sub 0/ of the 4f level were measured to be epsilon /sub 0/=540+or-100 eV and Gamma /sub 0 /=225+or-57 eV, in good agreement with the values obtained with the standard optical potential description of the pion-nucleus interaction. Estimating the influence of the finite nuclear size, the deformation induced through the strong interaction between the pion and the finite nucleus, and the relative magnitude between the strong and the electromagnetic quadrupole coupling constants values for the spectroscopic quadrupole moment of Q=3.30+or-0.06 b, and for the intrinsic quadrupole moment of Q/sub 0/=7.06+or-0.12 b are obtained. (28 refs).
Lacki, Brian C.; Beck, Rainer
2013-04-01
Equipartition arguments provide an easy way to find a characteristic scale for the magnetic field from radio emission by assuming that the energy densities in cosmic rays and magnetic fields are the same. Yet most of the cosmic ray content in star-forming galaxies is in protons, which are invisible in radio emission. Therefore, the argument needs assumptions about the proton spectrum, typically that of a constant proton/electron ratio. In some environments, particularly starburst galaxies, the reasoning behind these assumptions does not necessarily hold: secondary pionic positrons and electrons may be responsible for most of the radio emission, and strong energy losses can alter the proton/electron ratio. We derive an equipartition expression that should work in a hadronic loss-dominated environment like starburst galaxies. Surprisingly, despite the radically different assumptions from the classical equipartition formula, numerically the results for starburst magnetic fields are similar. We explain this fortuitous coincidence using the energetics of secondary production and energy loss times. We show that these processes cause the proton/electron ratio to be ˜100 for GHz-emitting electrons in starbursts.
Energy Technology Data Exchange (ETDEWEB)
El-Khoury, P
1998-04-15
The study of exotic atoms, in which an orbiting electron of a normal atom is replaced by a negatively charged particle ({pi}{sup -}, {mu}{sup -}, p, {kappa}{sup -}, {sigma}{sup -},...) may provide information on the orbiting particle and the atomic nucleus, as well as on their interaction. In this work, we were interested in pionic atoms ({pi}{sup -14} N) on the one hand in order to determine the pion mass with high accuracy (4 ppm), and on the other hand in antiprotonic atoms (pp-bar) in order to study the strong nucleon-antinucleon interaction at threshold. In this respect, a high-resolution crystal spectrometer was coupled to a cyclotron trap which provides a high stop density for particles in gas targets at low pressure. Using curved crystals, an extended X-ray source could be imaged onto the detector. Charge-Coupled Devices were used as position sensitive detectors in order to measure the Bragg angle of the transition to a high precision. The use of gas targets resolved the ambiguity owing to the number of K electrons for the value of the pion mass, and, for the first time, strong interaction shift and broadening of the 2p level in antiprotonic hydrogen were measured directly. (author)
Modelling excited states of weakly bound complexes with density functional theory.
Briggs, Edward A; Besley, Nicholas A
2014-07-28
The binding within the ethene-argon and formaldehyde-methane complexes in the ground and electronically excited states is studied with equation of motion coupled cluster theory (EOM-CCSD), second-order Møller-Plesset perturbation theory (MP2) and density functional theory with dispersion corrections (DFT-D). Electronically excited states are studied within MP2 and Kohn-Sham DFT formalisms by exploiting a procedure called the maximum overlap method that allows convergence of the relevant self-consistent field equations to higher energy (or excited state) solutions. Potential energy curves computed using MP2 are in good agreement with the EOM-CCSD calculations for both the valence and Rydberg excited states studied. For the DFT-D approach, B3LYP-D3/aug-cc-pVTZ calculations are found to be in agreement with EOM-CCSD for the ground and valence excited states. However, for the π3s Rydberg state of ethene-argon and the n3s Rydberg state of formaldehyde-methane significant deviation is observed, and this disagreement with EOM-CCSD is present for a variety of DFT-D based approaches. Variation of the parameters within the D2 dispersion correction results in closer agreement with EOM-CCSD for the Rydberg states but demonstrates that a different parameterisation from the ground state is required for these states. This indicates that time-dependent density functional theory calculations based upon a DFT-D reference may be satisfactory for excitations to valence states, but will potentially be inaccurate for excitations to Rydberg states, or more generally states where the nature of the electron density is significantly different from the ground state.
Backbone resonance assignments for G protein α(i3) subunit in the GDP-bound state.
Mase, Yoko; Yokogawa, Mariko; Osawa, Masanori; Shimada, Ichio
2014-10-01
Guanine-nucleotide binding proteins (G proteins) serve as molecular switches in signaling pathways, by coupling the activation of G protein-coupled receptors (GPCRs) at the cell surface to intracellular responses. In the resting state, G protein forms a heterotrimer, consisting of the G protein α subunit with GDP (Gα·GDP) and the G protein βγ subunit (Gβγ). Ligand binding to GPCRs promotes the GDP-GTP exchange on Gα, leading to the dissociation of the GTP-bound form of Gα (Gα·GTP) and Gβγ. Then, Gα·GTP and Gβγ bind to their downstream effector enzymes or ion channels and regulate their activities, leading to a variety of cellular responses. Finally, Gα hydrolyzes the bound GTP to GDP and returns to the resting state by re-associating with Gβγ. The G proteins are classified with four major families based on the amino acid sequences of Gα: i/o, s, q/11, and 12/13. Here, we established the backbone resonance assignments of human Gαi3, a member of the i/o family with a molecular weight of 41 K, in complex with GDP. The chemical shifts were compared with those of Gα(i3) in complex with a GTP-analogue, GTPγS, which we recently reported, indicating that the residues with significant chemical shift differences are mostly consistent with the regions with the structural differences between the GDP- and GTPγS-bound states, as indicated in the crystal structures. The assignments of Gα(i3)·GDP would be useful for the analyses of the dynamics of Gα(i3) and its interactions with various target molecules.
Han, Chengcheng; Matsumoto, Shigeki; Nojiri, Mihoko M; Takeuchi, Michihisa
2016-01-01
A colored heavy particle with sufficiently small width may form non-relativistic bound states when they are produced at the large hadron collider\\,(LHC), and they can annihilate into a diphoton final state. The invariant mass of the diphoton would be around twice of the colored particle mass. In this paper, we study if such bound state can be responsible for the 750 GeV diphoton excess reported by ATLAS and CMS. We found that the best-fit signal cross section is obtained for the SU(2)$_L$ singlet colored fermion $X$ with $Y_X=4/3$. Having such an exotic hypercharge, the particle is expected to decay through some higher dimensional operators, consistent with the small width assumption. The decay of $X$ may involve a stable particle $\\chi$, if both $X$ and $\\chi$ are odd under some conserved $Z_2$ symmetry. In that case, the particle $X$ suffers from the constraints of jets + missing $E_T$ searches by ATLAS and CMS at 8 TeV and 13 TeV. We found that such a scenario still survives if the mass difference between ...
Energy Technology Data Exchange (ETDEWEB)
Zheng, Rui [School of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou (China); Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China); Li, Song, E-mail: lsong@yangtzeu.edu.cn [School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Chen, Shan-Jun; Chen, Yan [School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Zheng, Li-Min [Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China)
2015-09-08
Highlights: • A two-dimensional potential for Ar–BrCl is constructed at the CCSD(T) level. • The PES is characterized by three minima and two saddle points between them. • Bound state calculations were carried out for the complex. - Abstract: The intermolecular potential energy surface (PES) of the ground electronic state for the Ar–BrCl dimer is constructed at the CCSD(T) level with the aug-cc-pVQZ basis set and mid-bond functions. The PES is characterized by three minima and two saddle points. The global minimum corresponding to a collinear Ar–BrCl configuration, which has been observed experimentally, is located at R = 4.10 Å and θ = 2.5° with a well depth of −285.207 cm{sup −1}. A nearly T-shaped structure and an anti-linear Ar–ClBr geometry is also predicted. The bound state calculations are preformed to study intermolecular vibrational modes, rotational levels and average structures for the complex. Our transition frequencies, spectroscopic constants and average structures for all isotopomers of the collinear isomer agree well with experimental data. We have also provided pure rotational transitional frequencies for both nearly T-shaped and anti-linear isomers. These results are significant for further experimental investigations of the Ar–BrCl dimer.
WKB formalism and a lower limit for the energy eigenstates of bound states for some potentials
Barragan-Gil, L F; Barragan-Gil, Luis F.; Camacho, Abel
2007-01-01
In the present work the conditions appearing in the WKB approximation formalism of quantum mechanics are analyzed. It is shown that, in general, a careful definition of an approximation method requires the introduction of two length parameters, one of them always considered in the text books on quantum mechanics, whereas the second one is usually neglected. Afterwards we define a particular family of potentials and prove, resorting to the aforementioned length parameters, that we may find an energy which is a lower bound to the ground energy of the system. The idea is applied to the case of a harmonic oscillator and also to a particle freely falling in a homogeneous gravitational field, and in both cases the consistency of our method is corroborated. This approach, together with the Rayleigh--Ritz formalism, allows us to define an energy interval in which the ground energy of any potential, belonging to our family, must lie.
Search for the He-{\\eta} bound states with the WASA-at-COSY facility
Skurzok, M; Moskal, P
2012-01-01
The eta-mesic nuclei in which the {\\eta} meson is bound with nucleus via strong interaction was postulated already in 1986, however till now no experiment confirmed empirically its existence. The discovery of this new kind of an exotic nuclear matter would be very important for better understanding of the {\\eta} meson structure and its interaction with nucleons. The search for {\\eta}-mesic helium is carried out with high statistic and high acceptance with the WASA-at-COSY detection setup in the Research Center Juelich. The search is conducted via the measurement of the excitation function for the chosen decay channels of the 4He-{\\eta} system. Till now two reactions dd --> (4He-{\\eta})_bs --> 3Hep\\pi- and dd --> (4He-{\\eta})_bs --> 3 Hen{\\pi}0 were measured with the beam momentum ramped around the eta production threshold. This report includes the description of experimental method and status of the analysis.
Energy Technology Data Exchange (ETDEWEB)
Fujioka, H., E-mail: fujioka@scphys.kyoto-u.ac.jp [Kyoto University (Japan); Ayyad, Y. [Osaka University, RCNP (Japan); Benlliure, J. [Universidade de Santiago de Compostela (Spain); Brinkmann, K.-T.; Friedrich, S.; Geissel, H. [Universität Giessen (Germany); Gellanki, J. [University of Groningen, KVI-CART (Netherlands); Guo, C. [Beihang University (China); Gutz, E. [Universität Giessen (Germany); Haettner, E. [GSI (Germany); Harakeh, M. N. [University of Groningen, KVI-CART (Netherlands); Hayano, R. S. [The University of Tokyo (Japan); Higashi, Y.; Hirenzaki, S. [Nara Women’s University (Japan); Hornung, C. [Universität Giessen (Germany); Igarashi, Y. [KEK (Japan); Ikeno, N. [Tohoku University (Japan); Itahashi, K.; Iwasaki, M. [Nishina Center, RIKEN (Japan); Jido, D. [Tokyo Metropolitan University (Japan); Collaboration: for the Super-FRS Collaboration; and others
2015-08-15
The possible existence of η′-nucleus bound states has been put forward through theoretical and experimental studies. It is strongly related to the η′ mass at finite density, which is expected to be reduced because of the interplay between the U{sub A}(1) anomaly and partial restoration of chiral symmetry. The investigation of the C(p,d) reaction at GSI and FAIR, as well as an overview of the experimental program at GSI and future plans at FAIR are discussed.
Directory of Open Access Journals (Sweden)
Shahar Hod
2015-10-01
Full Text Available Rotating black holes can support quasi-stationary (unstable bound-state resonances of massive scalar fields in their exterior regions. These spatially regular scalar configurations are characterized by instability timescales which are much longer than the timescale M set by the geometric size (mass of the central black hole. It is well-known that, in the small-mass limit α≡Mμ≪1 (here μ is the mass of the scalar field, these quasi-stationary scalar resonances are characterized by the familiar hydrogenic oscillation spectrum: ωR/μ=1−α2/2n¯02, where the integer n¯0(l,n;α→0=l+n+1 is the principal quantum number of the bound-state resonance (here the integers l=1,2,3,… and n=0,1,2,… are the spheroidal harmonic index and the resonance parameter of the field mode, respectively. As it depends only on the principal resonance parameter n¯0, this small-mass (α≪1 hydrogenic spectrum is obviously degenerate. In this paper we go beyond the small-mass approximation and analyze the quasi-stationary bound-state resonances of massive scalar fields in rapidly-spinning Kerr black-hole spacetimes in the regime α=O(1. In particular, we derive the non-hydrogenic (and, in general, non-degenerate resonance oscillation spectrum ωR/μ=1−(α/n¯2, where n¯(l,n;α=(l+1/22−2mα+2α2+1/2+n is the generalized principal quantum number of the quasi-stationary resonances. This analytically derived formula for the characteristic oscillation frequencies of the composed black-hole-massive-scalar-field system is shown to agree with direct numerical computations of the quasi-stationary bound-state resonances.
Influence of quasi-bound states on the carrier capture into quantum dots
DEFF Research Database (Denmark)
Magnúsdóttir, Ingibjörg; Uskov, A.; Bischoff, Svend;
2002-01-01
An important characteristic of quantum dot (QD) materials is the timescale on which carriers are captured into the dots and relax to their ground state. The properties of devices based on QDs, such as lasers, thus rely on efficient carrier feeding to the active QD states. These processes are beli......An important characteristic of quantum dot (QD) materials is the timescale on which carriers are captured into the dots and relax to their ground state. The properties of devices based on QDs, such as lasers, thus rely on efficient carrier feeding to the active QD states. These processes...
Bound states of two-dimensional Schr\\"{o}dinger-Newton equations
Stubbe, Joachim
2008-01-01
We prove an existence and uniqueness result for ground states and for purely angular excitations of two-dimensional Schr\\"{o}dinger-Newton equations. From the minimization problem for ground states we obtain a sharp version of a logarithmic Hardy-Littlewood-Sobolev type inequality.
Directory of Open Access Journals (Sweden)
E. V. B. Leite
2015-01-01
Full Text Available Based on the Kaluza-Klein theory, we study the Aharonov-Bohm effect for bound states for a relativistic scalar particle subject to a Coulomb-type potential. We introduce this scalar potential as a modification of the mass term of the Klein-Gordon equation, and a magnetic flux through the line element of the Minkowski spacetime in five dimensions. Then, we obtain the relativistic bound states solutions and calculate the persistent currents.
Determination of an $\\eta^3$He bound state from the $pd \\to \\eta^3$He reaction at threshold
Xie, Ju-Jun; Oset, Eulogio; Moskal, Pawel; Skurzok, Magdalena; Wilkin, Colin
2016-01-01
We analyze the data on cross sections and asymmetries for the $pd (dp) \\to \\eta ^3{\\rm He}$ reaction close to threshold and look for bound states of the $\\eta ^3 {\\rm He}$ system. Rather than parameterizing the scattering matrix, as is usually done, we develop a framework in which the $\\eta ^3 {\\rm He}$ optical potential is the key ingredient, and its strength, together with some production parameters, are fitted to the available experimental data. The relationship of the scattering matrix to the optical potential is established using the Bethe-Salpeter equation and the $\\eta ^3 {\\rm He}$ loop function incorporates the range of the interaction given by the empirical $^3 {\\rm He}$ density. We predict the existence of a weakly bound state with a binding of around $0.3$~MeV and a width of about $3$~MeV. By fitting the potential we can also evaluate the $\\eta ^3 {\\rm He}$ scattering length, including its sign, thus resolving the ambiguity in the former analyses.
Coupled-channels Faddeev AGS calculation of $K^{-}ppn$ and $K^{-}ppp$ quasi-bound states
Marri, S
2016-01-01
Using separable $\\bar{K}N-\\pi\\Sigma$ potentials in the Faddeev equations, we calculated the binding energies and widths of the $K^{-}pp$, $K^{-}ppn$ and $K^{-}ppp$ quasi-bound states on the basis of three- and four-body Alt-Grassberger-Sandhas equations in the momentum representation. One- and two-pole version of $\\bar{K}N-\\pi\\Sigma$ interaction are considered and the dependence of the resulting few-body energy on the two-body $\\bar{K}N-\\pi\\Sigma$ potential was investigated. The $s$-wave [3+1] and [2+2] sub-amplitudes are obtained by using the Hilbert-Schmidt expansion procedure for the integral kernels. As a result, we found a four-body resonance of the $K^{-}ppn$ and $K^{-}ppp$ quasi-bound states with a binding energy in the range $B_{K^{-}ppn}\\sim{55-70}$ and $B_{K^{-}ppp}\\sim{90-100}$ MeV, respectively. The calculations yielded full width of $\\Gamma_{K^{-}ppn}\\sim{16-20}$ and $\\Gamma_{K^{-}ppp}\\sim{7-20}$ MeV.
Scattering and Bound States of a Spin-1/2 Neutral Particle in the Cosmic String Spacetime
Directory of Open Access Journals (Sweden)
Fabiano M. Andrade
2017-01-01
Full Text Available In this paper the relativistic quantum dynamics of a spin-1/2 neutral particle with a magnetic moment μ in the cosmic string spacetime is reexamined by applying the von Neumann theory of self-adjoint extensions. Contrary to previous studies where the interaction between the spin and the line of charge is neglected, here we consider its effects. This interaction gives rise to a point interaction: ∇·E=(2λ/αδ(r/r. Due to the presence of the Dirac delta function, by applying an appropriated boundary condition provided by the theory of self-adjoint extensions, irregular solutions for the Hamiltonian are allowed. We address the scattering problem obtaining the phase shift, S-matrix, and the scattering amplitude. The scattering amplitude obtained shows a dependency with energy which stems from the fact that the helicity is not conserved in this system. Examining the poles of the S-matrix we obtain an expression for the bound states. The presence of bound states for this system has not been discussed before in the literature.
Exact calculations of a quasi-bound state in the $\\bar{K} \\bar{K} N$ system
Shevchenko, N V
2015-01-01
Dynamically exact calculations of a quasi-bound state in the $\\bar{K}\\bar{K}N$ three-body system are performed using Faddeev-type AGS equations. As input two phenomenological and one chirally motivated $\\bar{K}N$ potentials are used, which describe the experimental information on the $\\bar{K}N$ system equally well and produce either a one- or two-pole structure of the $\\Lambda(1405)$ resonance. For the $\\bar{K}\\bar{K}$ interaction separable potentials are employed that are fitted to phase shifts obtained from two theoretical models. The first one is a phenomenological $\\bar{K}\\bar{K}$ potential based on meson exchange, which is derived by SU(3) symmetry arguments from the J\\"ulich $\\pi \\pi - \\bar{K} K$ coupled-channels model. The other interaction is a variant of the first one, which is adjusted to the $KK$ s-wave scattering length recently determined in lattice QCD simulations. The position and width of the $\\bar{K}\\bar{K}N$ quasi-bound state is evaluated in two ways: (i) by a direct pole search in the compl...
Coupled-channels Faddeev AGS calculation of K{sup -}ppn and K{sup -}ppp quasi-bound states
Energy Technology Data Exchange (ETDEWEB)
Marri, S.; Kalantari, S.Z. [Isfahan University of Technology, Department of Physics, Isfahan (Iran, Islamic Republic of)
2016-09-15
Using separable anti KN - πΣ potentials in the Faddeev equations, we calculated the binding energies and widths of the K{sup -}pp, K{sup -}ppn and K{sup -}ppp quasi-bound states on the basis of three- and four-body Alt-Grassberger-Sandhas equations in the momentum representation. One- and two-pole version of anti KN - πΣ interaction are considered and the dependence of the resulting few-body energy on the two-body anti KN - πΣ potential was investigated. The s -wave [3 + 1] and [2 + 2] sub-amplitudes are obtained by using the Hilbert-Schmidt expansion procedure for the integral kernels. As a result, we found a four-body resonance of the K{sup -} ppn and K{sup -}ppp quasi-bound states with a binding energy in the range B{sub K{sup -}ppn} ∝ 55-70 and B{sub K{sup -}ppp} ∝ 90-100 MeV, respectively. The calculations yielded full width of Γ{sub K{sup -}ppn} ∝ 16-20 and Γ{sub K{sup -}ppp} ∝ 7-20 MeV. (orig.)
Search for the He-η bound states with the WASA-at-COSY facility
Directory of Open Access Journals (Sweden)
Krzemien W.
2012-12-01
Full Text Available The η-mesic nuclei in which the η meson is bound with nucleus via strong interaction was postulated already in 1986, however till now no experiment confirmed empirically its existence. The discovery of this new kind of an exotic nuclear matter would be very important for better understanding of the η meson structure and its interaction with nucleons. The search for η-mesic helium is carried out with high statistic and high acceptance with the WASA-at-COSY detection setup in the Research Center Jülich. The search is conducted via the measurement of the excitation function for the chosen decay channels of the 4He-η system. Till now two reactions dd → (4He-ηbs → 3Hepπ− and dd → (4He-ηbs → 3Henπ0 were measured with the beam momentum ramped around the η production threshold. This report includes the description of experimental method and status of the analysis.
The generalized pseudospectral approach to the bound states of the Hulthén and the Yukawa potentials
Indian Academy of Sciences (India)
Amlan K Roy
2005-07-01
The generalized pseudospectral (GPS) method is employed to calculate the bound states of the Hulthén and the Yukawa potentials in quantum mechanics, with special emphasis on higher excited states and stronger couplings. Accurate energy eigenvalues, expectation values and radial probability densities are obtained through a non-uniform and optimal spatial discretization of the radial Schrödinger equation. Results accurate up to thirteen to fourteen significant figures are reported for all the 55 eigenstates of both these potentials with ≤ 10 for arbitrary values of the screening parameters covering a wide range of interaction. Furthermore, excited states as high as = 17 have been computed with good accuracy for both these potentials. Excellent agreement with the available literature data has been observed in all cases. The > 6 states of the Yukawa potential has been considerably improved over all other existing results currently available, while the same for Hulthén potential are reported here for the first time. Excepting the 1 and 2 states of the Yukawa potential, the present method surpasses the accuracy of all other existing results in the stronger coupling region for all other states of both these systems. This offers a simple and efficient scheme for the accurate calculation of these and other screened Coulomb potentials.
Occupation of quasi-bound states by electrons in a Schwarzschild field
Energy Technology Data Exchange (ETDEWEB)
Galtsov, D.V.; Pomerantseva, G.V.; Chizhov, G.A.
1983-08-01
It is noted that quasi-steady states at energies omega less than mu exist near a Schwarzschild black hole. The occupation of these states by massive spinor particles is examined in the Pauli approximation for small black holes (mu)(M) much less than 1. It is shown that, as in the case of a scalar field, the occupation process is a thermal one. 7 references.
A Transformation Approach to Optimal Control Problems with Bounded State Variables
Hanafy, Lawrence Hanafy
1971-01-01
A technique is described and utilized in the study of the solutions to various general problems in optimal control theory, which are converted in to Lagrange problems in the calculus of variations. This is accomplished by mapping certain properties in Euclidean space onto closed control and state regions. Nonlinear control problems with a unit m cube as control region and unit n cube as state region are considered.
Atomic bound state and scattering properties of effective momentum-dependent potentials
Dharuman, Gautham; Verboncoeur, John; Christlieb, Andrew; Murillo, Michael S.
2016-10-01
Effective classical dynamics provide a potentially powerful avenue for modeling large-scale dynamical quantum systems. We have examined the accuracy of a Hamiltonian-based approach that employs effective momentum-dependent potentials (MDPs) within a molecular-dynamics framework through studies of atomic ground states, excited states, ionization energies, and scattering properties of continuum states. Working exclusively with the Kirschbaum-Wilets (KW) formulation with empirical MDPs [C. L. Kirschbaum and L. Wilets, Phys. Rev. A 21, 834 (1980), 10.1103/PhysRevA.21.834], optimization leads to very accurate ground-state energies for several elements (e.g., N, F, Ne, Al, S, Ar, and Ca) relative to Hartree-Fock values. The KW MDP parameters obtained are found to be correlated, thereby revealing some degree of transferability in the empirically determined parameters. We have studied excited-state orbits of electron-ion pair to analyze the consequences of the MDP on the classical Coulomb catastrophe. From the optimized ground-state energies, we find that the experimental first- and second-ionization energies are fairly well predicted. Finally, electron-ion scattering was examined by comparing the predicted momentum transfer cross section to a semiclassical phase-shift calculation; optimizing the MDP parameters for the scattering process yielded rather poor results, suggesting a limitation of the use of the KW MDPs for plasmas.
Indian Academy of Sciences (India)
S H Patil; K D Sen
2012-01-01
Using dimensional analyses, the scaling properties of the Heisenberg uncertainty relationship as well as the various information theoretical uncertainty-like relationships are derived for the bound states corresponding to the superposition of the power potential of the form () = + $^{n_{i}}, where , , , are parameters, in the free state as well as in the additional presence of a spherical penetrable boundary wall located at radius The uncertainty product and all other net information measures are shown here to depend only on the parameters [] defined by the ratios /$^{(n_{i}+2)/(n+2)}$. Introduction of a finite potential, V at the radial distance ≥ results in a complete set of scaling parameters given by [, 1, 2], where 1 is given by 1/(n+2) and 2 = V/()2/(+2).
Weakly bound states of two- and three-boson systems in the crossover from two to three dimensions
DEFF Research Database (Denmark)
Yamashita, Marcelo; Bellotti, Filipe Furlan; Frederico, Tobias
2015-01-01
. In this paper we study weakly bound states of non-relativistic two and three boson systems when passing continuously from a three (3D) to a two-dimensional (2D) regime within a 'squeezed dimension' model. We use periodic boundary conditions to derive a surprisingly simple form of the three-boson Schr{\\"o}dinger...... equation in momentum space that we solve numerically. Our results show a distinct dimensional crossover as three-boson states will either disappear into the continuum or merge with a 2D counterpart, and also a series of sharp transitions in the ratios of three-body and two-body energies from being purely 2...
Inversion symmetry breaking of atomic bound states in strong and short laser fields
Stooß, Veit; Ott, Christian; Blättermann, Alexander; Ding, Thomas; Pfeifer, Thomas
2015-01-01
In any atomic species, the spherically symmetric potential originating from the charged nucleus results in fundamental symmetry properties governing the structure of atomic states and transition rules between them. If atoms are exposed to external electric fields, these properties are modified giving rise to energy shifts such as the AC Stark-effect in varying fields and, contrary to this in a constant (DC) electric field for high enough field strengths, the breaking of the atomic symmetry which causes fundamental changes in the atom's properties. This has already been observed for atomic Rydberg states with high principal quantum numbers. Here, we report on the observation of symmetry breaking effects in Helium atoms for states with principal quantum number n=2 utilizing strong visible laser fields. These findings were enabled by temporally resolving the dynamics better than the sub-optical cycle of the applied laser field, utilizing the method of attosecond transient absorption spectroscopy (ATAS). We ident...
Feedback control of time-delay systems with bounded control and state
Directory of Open Access Journals (Sweden)
M. Dambrine
1995-01-01
Full Text Available This paper is concerned with the problem of stabilizing linear time-delay systems under state and control linear constraints. For this, necessary and sufficient conditions for a given non-symmetrical polyhedral set to be positively invariant are obtained. Then existence conditions of linear state feedback control law respecting the constraints are established, and a procedure is given in order to calculate such a controller. The paper concerns memoryless controlled systems but the results can be applied to cases of delayed controlled systems. An example is given.
Photonic realization of topologically protected bound states in domain-wall waveguide arrays
Lee-Thorp, James P; Xu, Xinan; Yang, Jinghui; Fefferman, Charles L; Wong, Chee Wei; Weinstein, Michael I
2016-01-01
We present an analytical theory of topologically protected photonic states for the two-dimensional Maxwell equations for a class of continuous periodic dielectric structures, modulated by a domain wall. We further numerically confirm the applicability of this theory for three-dimensional structures.
An Efficient Implementation of Non-Linear Limit State Analysis Based on Lower-Bound Solutions
DEFF Research Database (Denmark)
Damkilde, Lars; Schmidt, Lotte Juhl
2005-01-01
Limit State analysis has been used in design for decades e.g. the yield line theory for concrete slabs or slip line solutions in geotechnics. In engineering practice manual methods have been dominating but in recent years the interest in numerical methods has been increasing. In this respect...
Abramov, D. I.; Gusev, V. V.; Ponomarev, L. I.
1999-06-01
The uniform method of numerical investigation of bound states and scattering processes 2→ 2 (including resonance states) in the Coulomb three-body (CTB) systems is developed. It is based on the adiabatic hyperspherical approach (AHSA) and includes the numerical realization and applications to the three-body mesic atomic systems. The results of calculations of bound states of these systems (including the local characteristics of the wave functions) and the scattering processes 2→ 2 (including the characteristics of the resonance states) are presented.
Energy Technology Data Exchange (ETDEWEB)
Abramov, D.I. [St.-Petersburg State University (Russian Federation); Gusev, V.V. [Institute for High Energy Physics (Russian Federation); Ponomarev, L.I. [Russian Research Center ' Kurchatov Institute' (Russian Federation)
1999-06-15
The uniform method of numerical investigation of bound states and scattering processes 2{sup {yields}} 2 (including resonance states) in the Coulomb three-body (CTB) systems is developed. It is based on the adiabatic hyperspherical approach (AHSA) and includes the numerical realization and applications to the three-body mesic atomic systems. The results of calculations of bound states of these systems (including the local characteristics of the wave functions) and the scattering processes 2{sup {yields}} 2 (including the characteristics of the resonance states) are presented.
Probing transfer to unbound states of the ejectile with weakly bound 7Li on 93Nb
Pandit, S K; Mahata, K; Keeley, N; Parkar, V V; Rout, P C; Martel, I; Palshetkar, C S; Kumar, A; Ramachandran, K; Patale, P; Chatterjee, A; Kailas, S
2016-01-01
The two-step process of transfer followed by breakup is explored by measuring a rather complete set of exclusive data for reaction channels populating states in the ejectile continua of the $^7$Li+$^{93}$Nb system at energies close to the Coulomb barrier. The cross sections for $\\alpha+\\alpha$ events from one proton pickup were found to be smaller than those for $\\alpha+d$ events from one neutron stripping and $\\alpha+t$ events from direct breakup of $^7$Li. Coupled channels Born approximation and continuum discretized coupled channels calculations describe the data well and support the conclusion that the $\\alpha+d$ and $\\alpha+\\alpha$ events are produced by direct transfer to unbound states of the ejectile.
VARIATIONAL CALCULATION ON GROUND-STATE ENERGY OF BOUND POLARONS IN PARABOLIC QUANTUM WIRES
Institute of Scientific and Technical Information of China (English)
WANG ZHUANG-BING; WU FU-LI; CHEN QING-HU; JIAO ZHENG-KUAN
2001-01-01
Within the framework of Feynman path-integral variational theory, we calculate the ground-state energy of a polaron in parabolic quantum wires in the presence of a Coulomb potential. It is shown that the polaronic correction to the ground-state energy is more sensitive to the electron-phonon coupling constant than the Coulomb binding parameter,and it increases monotonically with decreasing effective wire radius. Moreover, compared to the results obtained by Feynman Haken variational path-integral theory, we obtain better results within the Feynman path-integral variational approach (FV approach). Applying our calculation to several polar semiconductor quantum wires, we find that the polaronic correction can be considerably large.
Population of bound excited states in intermediate-energy fragmentation reactions
Obertelli, A; Bazin, D; Campbell, C M; Cook, J M; Cottle, P D; Davies, A D; Dinca, D C; Glasmacher, T; Hansen, P G; Hoagland, T; Kemper, K W; Lecouey, J L; Müller, W F; Reynolds, R R; Roeder, B T; Terry, J R; Tostevin, J A; Yoneda, K; Zwahlen, H
2006-01-01
Fragmentation reactions with intermediate-energy heavy-ion beams exhibit a wide range of reaction mechanisms, ranging from direct reactions to statistical processes. We examine this transition by measuring the relative population of excited states in several sd-shell nuclei produced by fragmentation with the number of removed nucleons ranging from two to sixteen. The two-nucleon removal is consistent with a non-dissipative process whereas the removal of more than five nucleons appears to be mainly statistical.
Hadronic bound states in SU(2) from Dyson-Schwinger equations
Energy Technology Data Exchange (ETDEWEB)
Vujinovic, Milan [Karl-Franzens-Universitaet Graz, Institut fuer Physik, Graz (Austria); Williams, Richard [Justus-Liebig-Universitaet Giessen, Institut fuer Theoretische Physik, Giessen (Germany)
2015-03-01
By using the Dyson-Schwinger/Bethe-Salpeter formalism in Euclidean spacetime, we calculate the ground state spectrum of J ≤ 1 hadrons in an SU(2) gauge theory with two fundamental fermions. We show that the rainbow-ladder truncation, commonly employed in QCD studies, is unsuitable for a description of an SU(2) theory. This we remedy by truncating at the level of the quark-gluon vertex Dyson-Schwinger equation in a diagrammatic expansion. Results obtained within this novel approach show good agreement with lattice studies. These findings emphasize the need to use techniques more sophisticated than rainbow-ladder when investigating generic strongly interacting gauge theories. (orig.)
The effect of bound states on X-ray Thomson scattering for partially ionized plasmas
Nilsen, J.; Johnson, W.R.; Cheng, K. T.
2012-01-01
X-ray Thomson scattering is being developed as a method to measure the temperature, electron density, and ionization state of high energy density plasmas such as those used in inertial confinement fusion. X-ray laser sources have always been of interest because of the need to have a bright monochromatic x-ray source to overcome plasma emission and eliminate other lines in the background that complicate the analysis. With the advent of the xray free electron laser (X-FEL) at the SLAC Linac Coh...
Quantum states of neutral atoms bound in the magnetic field of a Kepler-guide
Institute of Scientific and Technical Information of China (English)
HE Ming; WANG Jin; ZHAN Ming-sheng
2003-01-01
The spectrum and the wave function of neutral atoms in the magnetic field of a Kepler-guide are presented by reducing a two-dimensional stationary Schrdinger equation to a one-dimensional hydrogen atom in Rydberg states. In addition, we set the scale for the atomic orbits and binding energy i n the quantum regime, and compare it with the outcome of the experiment. At the same time, we find that reducing the current and radius of the wire properly wil l increase the loading efficiency of the Kepler-guide.
Bound states in one-dimensional acoustic parity-time-symmetric lattices for perfect sensing
Zhao, Degang; Shen, Yaxi; Zhang, Yu; Zhu, Xuefeng; Yi, Lin
2016-08-01
In this letter, we study the propagation of acoustic waves through a one-dimensional multilayer structure composed of a thin defect layer sandwiched by two phononic crystals. Two kinds of defect states will generate in band gaps and both of them cause unitary transmission. However, they have very unlike field distributions due to the different contrasted acoustic impedances between the defect layer and its neighboring layers. Spectral positions of transmission peaks can be exactly determined by the resonant phase condition. In a non-dissipative system, these resonant states correspond to single crossing point of two eigenvalues of scattering matrix. When gain and loss are introduced to judiciously construct an acoustic parity-time-symmetric lattice, the crossing point will split into a pair of exceptional points (EPs). Interestingly, the EPs correspond to unidirectional zero reflection that is very sensitive to the thickness of defect layer. Taking advantage of this virtue, a very sensitive acoustic sensor can be designed, which has potentially applications in ultrasonic inspection, noise detection, ultrasonic medicine, etc.
Approximation algorithms for two-state anti-ferromagnetic spin systems on bounded degree graphs
Sinclair, Alistair; Thurley, Marc
2011-01-01
In a seminal paper (Weitz, 2006), Weitz gave a deterministic fully polynomial approximation scheme for counting exponentially weighted independent sets (which is the same as approximating the partition function of the hard-core model from statistical physics) in graphs of degree at most d, up to the critical activity for the uniqueness of the Gibbs measure on the infinite d-regular tree. More recently Sly (see also Galanis et al, 2011) showed that this is optimal in the sense that if there is an FPRAS for the hard-core partition function on graphs of maximum degree d for activities larger than the critical activity on the infinite d-regular tree then NP = RP. In this paper we extend Weitz's approach to derive a deterministic fully polynomial approximation scheme for the partition function of general two-state anti-ferromagnetic spin systems on graphs of maximum degree d, up to the corresponding critical point on the d-regular tree. The main ingredient of our result is a proof that for two-state anti-ferromagn...
Hyperspherical three-body model calculation for the bound $^{1,3}$S-states of Coulombic systems
Khan, Md Abdul
2014-01-01
In this paper, hyperspherical three-body model formalism has been applied for the calculation energies of the low-lying bound $^{1,3}$S (L=0)-states of neutral helium and helium like Coulombic three-body systems having nuclear charge (Z) in the range Z=2 to Z=92. The calculation of the coupling potential matrix elements of the two-body potentials has been simplified by the introduction of Raynal-Revai Coefficients (RRC). The three-body wave function in the Schr\\H{o}dinger equation when expanded in terms of hyperpherical harmonics (HH), leads to an infinite set of coupled differential equation (CDE). For practical reason the infinite set of CDE is truncated to a finite set and are solved by an exact numerical method known as renormalized Numerov method (RNM) to get the energy solution (E). The calculated energy is compared with the ones of the literature.
Bulgakov, Evgeny N.; Sadreev, Almas F.
2016-07-01
We consider the trapping of electrons with a definite spin polarization by bound states in the continuum (BSC) in the open Aharonov-Bohm rings in the presence of the Rashba spin-orbit interaction (RSOI). Neglecting the Zeeman term we show the existence of BSCs in the one-dimensional ring when the eigenstates of the closed ring are doubly degenerate. With account of the Zeeman term BSCs occur only at the points of threefold degeneracy. The BSCs are found in the parametric space of flux and RSOI strength in close pairs with opposite spin polarization. Thereby the spin polarization of electrons transmitted through the ring can be altered by minor variation of magnetic or electric field at the vicinity of these pairs. Numerical simulations of the two-dimensional open ring show similar results for the BSCs. Encircling the BSC points in the parametric space of the flux and the RSOI constant gives rise to a geometric phase.
Snelder, M; Golubov, A A; Asano, Y; Brinkman, A
2015-08-12
To guide experimental work on the search for Majorana zero-energy modes, we calculate the superconducting pairing symmetry of a three-dimensional topological insulator in combination with an s-wave superconductor. We show how the pairing symmetry changes across different topological regimes. We demonstrate that a dominant p-wave pairing relation is not sufficient to realise a Majorana zero-energy mode useful for quantum computation. Our main result is the relation between odd-frequency pairing and Majorana zero energy modes by using Green functions techniques in three-dimensional topological insulators in the so-called Majorana regime. We discuss thereafter how the pairing relations in the different regimes can be observed in the tunneling conductance of an s-wave proximised three-dimensional topological insulator. We discuss the necessity to incorporate a ferromagnetic insulator to localise the zero-energy bound state to the interface as a Majorana mode.
Garland, Gregory Ellis
The temperature dependence of transport properties of a moderately dense square well gas is studied in order to understand the effects of attractive forces (particularly bound states). The quantum cluster expansions of the Green -Kubo time correlation functions for the thermal conductivity, shear viscosity, and self-diffusion coefficients are given, and exact expressions to zeroth (Boltzmann level) and first order in the density are obtained. Specializing to Boltzmann statistics and the classical square well potential allows calculations of the kinetic potential parts of the first density correction; the important contributions to the remaining triple collision parts are discussed. Good agreement with molecular dynamics results is found; quantitative difference from real fluids are observed, however. Possible reasons for the discrepancies are discussed. A brief description of the ultility and limitations of the hard sphere model is given for comparison. The dynamics structure factor is calculated for a dense fluid of hard spheres and compared with recent neutron scattering data for Krypton.
Line bundle twisted chiral de Rham complex and bound states of D-branes on toric manifolds
Energy Technology Data Exchange (ETDEWEB)
Parkhomenko, S.E., E-mail: spark@itp.ac.ru [Landau Institute for Theoretical Physics, 142432 Chernogolovka, Moscow region (Russian Federation); Moscow Institute of Physics and Technology, 141707 Dolgoprudny, Moscow region (Russian Federation)
2014-04-15
In this note we calculate elliptic genus in various examples of twisted chiral de Rham complex on two-dimensional toric compact manifolds and Calabi–Yau hypersurfaces in toric manifolds. At first the elliptic genus is calculated for the line bundle twisted chiral de Rham complex on a compact smooth toric manifold and K3 hypersurface in P{sup 3}. Then we twist chiral de Rham complex by sheaves localized on positive codimension submanifolds in P{sup 2} and calculate in each case the elliptic genus. In the last example the elliptic genus of chiral de Rham complex on P{sup 2} twisted by SL(N) vector bundle with instanton number k is calculated. In all the cases considered we find the infinite tower of open string oscillator contributions and identify directly the open string boundary conditions of the corresponding bound state of D-branes.
Phillips, D R; Devine, N K
1998-01-01
The electromagnetic interactions of a relativistic two-body bound state are formulated in three dimensions using an equal-time (ET) formalism. This involves a systematic reduction of four-dimensional dynamics to a three-dimensional form by integrating out the time components of relative momenta. A conserved electromagnetic current is developed for the ET formalism. It is shown that consistent truncations of the electromagnetic current and the $NN$ interaction kernel may be made, order-by-order in the coupling constants, such that appropriate Ward-Takahashi identities are satisfied. A meson-exchange model of the $NN$ interaction is used to calculate deuteron vertex functions. Calculations of electromagnetic form factors for elastic scattering of electrons by deuterium are performed using an impulse-approximation current. Negative-energy components of the deuteron's vertex function and retardation effects in the meson-exchange interaction are found to have only minor effects on the deuteron form factors.
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
The interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states is derived newly from QCD in the case where the quark and the antiquark are of different flavors. The technique of the derivation is the usage of the irreducible decomposition of the Green's functions involved in the Bethe-Salpeter equation satisfied by the quark-antiquark four-point Green's function. The interaction kernel derived is given a closed and explicit expression which shows a specific structure of the kernel since the kernel is represented in terms of the quark, antiquark and gluon propagators and some kinds of quark, antiquark and/or gluon three, four, five and six-point vertices. Therefore,the expression of the kernel is not only convenient for perturbative calculations, but also suitable for nonperturbative investigations.
Bulgakov, Evgeny; Pichugin, Konstantin; Sadreev, Almas
2013-10-01
We show that two nonlinear resonant cavities aligned between two parallel waveguides can support self-induced bound states in the continuum (BSCs). These BSCs are symmetrical relative to an inversion of the waveguides and to inversion of the transport axis. Due to this BSCs can drop an incident wave from one waveguide to another with very high efficiency. We show also that the frequency of the efficient channel dropping can be tuned by injecting power. All these results are in good agreement with numerical solutions of the Maxwell equations in a two-dimensional photonic crystal of GaAs rods holding two parallel waveguides and two defects made of a Kerr medium.
Wilkinson, Iain; Boguslavskiy, Andrey E; Mikosch, Jochen; Bertrand, Julien B; Wörner, Hans Jakob; Villeneuve, David M; Spanner, Michael; Patchkovskii, Serguei; Stolow, Albert
2014-05-28
The excited state dynamics of isolated sulfur dioxide molecules have been investigated using the time-resolved photoelectron spectroscopy and time-resolved photoelectron-photoion coincidence techniques. Excited state wavepackets were prepared in the spectroscopically complex, electronically mixed (B̃)(1)B1/(Ã)(1)A2, Clements manifold following broadband excitation at a range of photon energies between 4.03 eV and 4.28 eV (308 nm and 290 nm, respectively). The resulting wavepacket dynamics were monitored using a multiphoton ionisation probe. The extensive literature associated with the Clements bands has been summarised and a detailed time domain description of the ultrafast relaxation pathways occurring from the optically bright (B̃)(1)B1 diabatic state is presented. Signatures of the oscillatory motion on the (B̃)(1)B1/(Ã)(1)A2 lower adiabatic surface responsible for the Clements band structure were observed. The recorded spectra also indicate that a component of the excited state wavepacket undergoes intersystem crossing from the Clements manifold to the underlying triplet states on a sub-picosecond time scale. Photoelectron signal growth time constants have been predominantly associated with intersystem crossing to the (c̃)(3)B2 state and were measured to vary between 750 and 150 fs over the implemented pump photon energy range. Additionally, pump beam intensity studies were performed. These experiments highlighted parallel relaxation processes that occurred at the one- and two-pump-photon levels of excitation on similar time scales, obscuring the Clements band dynamics when high pump beam intensities were implemented. Hence, the Clements band dynamics may be difficult to disentangle from higher order processes when ultrashort laser pulses and less-differential probe techniques are implemented.
Oh, Ki-Dong; Deymier, P. A.
2004-04-01
We have used the restricted path-integral molecular dynamics method to study the correlated electronic structure of a half-filled expanded three-dimensional hydrogenoid body-centered cubic lattice at finite temperatures. Starting from a paramagnetic metallic state with electron gas character, we find that bound electrons form upon expansion of the lattice. The bound electrons are spatially localized with their center for the motion of gyration located on ionic positions. The region of coexistence of bound and unbound states in the temperature-density plane is reminiscent of that associated with a first-order transition. At constant temperature, the number of bound electrons increases monotonously with decreasing density. The width of the region of coexistence narrows with increasing temperature.
Revisiting surface-integral formulations for one-nucleon transfers to bound and resonance states
Escher, J E; Arbanas, G; Elster, Ch; Eremenko, V; Hlophe, L; Nunes, F M
2014-01-01
One-nucleon transfer reactions, in particular (d,p) reactions, have played a central role in nuclear structure studies for many decades. Present theoretical descriptions of the underlying reaction mechanisms are insufficient for addressing the challenges and opportunities that are opening up with new radioactive beam facilities. We investigate a theoretical approach that was proposed recently to address shortcomings in the description of transfers to resonance states. The method builds on ideas from the very successful R-matrix theory; in particular it uses a similar separation of the parameter space into interior and exterior regions, and introduces a parameterization that can be related to physical observables, which, in principle, makes it possible to extract meaningful spectroscopic information from experiments. We carry out calculations, for a selection of isotopes and energies, to test the usefulness of the new approach.
Donor-bound electron states in a two-dimensional quantum ring under uniform magnetic field
Institute of Scientific and Technical Information of China (English)
Jia Bo-Yong; Yu Zhong-Yuan; Liu Yu-Min; Han Li-Hong; Yao Wen-Jie; Feng Hao; Ye Han
2011-01-01
The electron states in a two-dimensional GaAs/AlGaAs quantum ring are theoretically studied in effective mass approximation. On-centre donor impurity and uniform magnetic field perpendicular to the ring plane are taken into account. The energy spectrum with different angular momentum changes dramatically with the geometry of the ring.The donor impurity reduces the energies with an almost fixed value; however, the magnetic field alters energies in a more complex way. For example, energy levels under magnetic field will cross each other when increasing the inner radius and outer radius of the ring, leading to the fact that the arrangement of energy levels is distinct in certain geometry of the ring. Moreover, energy levels with negative angular momentum exhibit the non-monotonous dependence on the increasing magnetic field.
Mai, Sebastian; Marquetand, Philipp; González, Leticia
2014-05-28
The importance of triplet states in the photorelaxation dynamics of SO2 is studied by mixed quantum-classical dynamics simulations. Using the SHARC method, standing for Surface Hopping including ARbitrary Couplings, intersystem crossing (ISC) processes caused by spin-orbit coupling are found occurring on an ultrafast time scale (few 100 fs) and thus competing with internal conversion. While in the singlet-only dynamics only oscillatory population transfer between the (1)B1 and (1)A2 states is observed, in the dynamics including singlet and triplet states we find additionally continuous ISC to the (3)B2 state and to a smaller extent to the (3)B1/(3)A2 coupled states. The populations obtained from the dynamics are discussed with respect to the overall nuclear motion and in the light of recent TRPEPICO studies [I. Wilkinson, A. E. Boguslavskiy, J. Mikosch, D. M. Villeneuve, H.-J. Wörner, M. Spanner, S. Patchkovskii, and A. Stolow, "Excited state dynamics in SO2. I. Bound state relaxation studied by time-resolved photoelectron-photoion coincidence spectroscopy," J. Chem. Phys. 140, 204301 (2014)].
Baryon properties and glueballs from Poincare-covariant bound-state equations
Sanchis-Alepuz, Helios
2012-01-01
In this thesis the covariant Bethe-Salpeter equation formalism is used to study some properties of ground-state baryons. This formalism relies on the knowledge of the interaction kernel among quarks and of the full quark propagator. For the interaction kernel, which is in principle a sum of infinitely many diagrams, I use the Ladder truncation. It amounts to reduce the interaction to a flavor-blind quark-mass independent vector-vector interaction between two quarks, mediated by a dressed gluon. The irreducible three-body interactions are neglected. The full quark propagator is obtained as a solution of the quark Dyson-Schwinger equation which is truncated such that, together with the truncation in the interaction kernel, chiral symmetry is correctly implemented. It is called Rainbow truncation, and together with the truncated kernel equation it constitutes the Rainbow-Ladder truncation of the Bethe-Salpeter equation. Any truncation induces the introduction of a model to account for the properties of the full ...
New Protocols and Lower Bound for Quantum Secret Sharing with Graph States
Javelle, Jérôme; Perdrix, Simon
2011-01-01
We introduce a new family of quantum secret sharing protocols with limited quantum resources which extends the protocols proposed by Markham and Sanders and by Broadbent, Chouha, and Tapp. Parametrized by a graph G and a subset of its vertices A, the protocol consists in: (i) encoding the quantum secret into the corresponding graph state by acting on the qubits in A; (ii) use a classical encoding to ensure the existence of a threshold. These new protocols realize ((k,n)) quantum secret sharing i.e., any set of at least k players among n can reconstruct the quantum secret, whereas any set of less than k players has no information about the secret. In the particular case where the secret is encoded on all the qubits, we explore the values of k for which there exists a graph such that the corresponding protocol realizes a ((k,n)) secret sharing. We show that for any threshold k> n-n^{0.68} there exists a graph allowing a ((k,n)) protocol. On the other hand, we prove that for any kn_0.
Christlieb, A.; Dharuman, G.; Verboncoeur, J.; Murillo, M. S.
2016-10-01
Modeling high energy-density experiments requires simulations spanning large length and time scales. These non-equilibrium experiments have time evolving ionization and partial degeneracy, obviating the direct use of the time-dependent Schrodinger equation. Therefore, efficient approximate methods are greatly needed. We have examined the accuracy of one such method based on an effective classical-dynamics approach employing effective momentum dependent potentials (MDPs) within a Hamiltonian framework that enables large-scale simulations. We have found that a commonly used formulation, based on Kirschbaum-Wilets MDPs leads to very accurate ground state energies and good first/second-ionization energies. The continuum scattering properties of free electrons were examined by comparing the momentum-transfer cross section (MTCS) predicted by KW MDP to a semi-classical phase-shift calculation. Optimizing the KW MDP parameters for the scattering process yielded poor MTCSs, suggesting a limitation of the use of KW MDP for plasmas. However, our new MDP yields MTCS values in much better agreement than KW MDP.
Directory of Open Access Journals (Sweden)
Susanne Fanghänel
Full Text Available Structure analysis of the cell-penetrating peptide transportan 10 (TP10 revealed an exemplary range of different conformations in the membrane-bound state. The bipartite peptide (derived N-terminally from galanin and C-terminally from mastoparan was found to exhibit prominent characteristics of (i amphiphilic α-helices, (ii intrinsically disordered peptides, as well as (iii β-pleated amyloid fibrils, and these conformational states become interconverted as a function of concentration. We used a complementary approach of solid-state (19F-NMR and circular dichroism in oriented membrane samples to characterize the structural and dynamical behaviour of TP10 in its monomeric and aggregated forms. Nine different positions in the peptide were selectively substituted with either the L- or D-enantiomer of 3-(trifluoromethyl-bicyclopent-[1.1.1]-1-ylglycine (CF3-Bpg as a reporter group for (19F-NMR. Using the L-epimeric analogs, a comprehensive three-dimensional structure analysis was carried out in lipid bilayers at low peptide concentration, where TP10 is monomeric. While the N-terminal region is flexible and intrinsically unstructured within the plane of the lipid bilayer, the C-terminal α-helix is embedded in the membrane with an oblique tilt angle of ∼ 55° and in accordance with its amphiphilic profile. Incorporation of the sterically obstructive D-CF3-Bpg reporter group into the helical region leads to a local unfolding of the membrane-bound peptide. At high concentration, these helix-destabilizing C-terminal substitutions promote aggregation into immobile β-sheets, which resemble amyloid fibrils. On the other hand, the obstructive D-CF3-Bpg substitutions can be accommodated in the flexible N-terminus of TP10 where they do not promote aggregation at high concentration. The cross-talk between the two regions of TP10 thus exerts a delicate balance on its conformational switch, as the presence of the α-helix counteracts the tendency of the
A model of charmed baryon-nucleon potential and 2- and 3-body bound states with charmed baryon
Maeda, Saori; Yokota, Akira; Hiyama, Emiko; Liu, Yan-Rui
2015-01-01
Potential models of the interaction between a charmed baryon ($Y_c$) and the nucleon ($N$) are constructed on the basis of a long-range meson ($\\pi$ and $\\sigma$) exchange potential as well as a short-distance quark exchange interaction. The quark cluster model is used to evaluate the short-range repulsion between $Y_c$ and $N$, while the meson exchange potentials are modified by a form factor at short distances. We determine the cutoff parameters of the form factors so as to fit the $NN$ scattering data with the same approach. The ground state charmed baryons, $\\Lambda_c$, $\\Sigma_c$ and $\\Sigma_c^*$, are included as $Y_c$, and channel couplings of relevant $Y_c N$ channels are taken into account. We propose four sets of parameters (a -- d), among which the most attractive potential (d) predicts bound $\\Lambda_c N$ $J^\\pi= 0^+$ and $1^+$ states. In order to apply the potential to a many-body problem, we construct an effective $\\Lambda_c N$ one-channel potential for the parameter set (d). It is applied to the...
Ikhdair, Sameer M
2011-01-01
The approximate analytical bound state solution of the Schr\\"odinger equation for the Manning-Rosen potential is carried out by taking a new approximation scheme to the orbital centrifugal term. The Nikiforov-Uvarov method is used in the calculations. We obtain analytic forms for the energy eigenvalues and the corresponding normalized wave functions in terms of the Jacobi polynomials or hypergeometric functions for different screening parameters 1/b. The rotational-vibrational energy states for a few diatomic molecules are calculated for arbitrary quantum numbers n and l with different values of the potential parameter {\\alpha}. The present numerical results agree within five decimal digits with the previously reported results for different 1/b values. A few special cases of the s-wave (l=0) Manning-Rosen potential and the Hulth\\'en potential are also studied. Keywords: Energy eigenvalues; Manning-Rosen potential; Nikiforov-Uvarov method, Approximation schemes. 03.65.-w; 02.30.Gp; 03.65.Ge; 34.20.Cf
Bettens, Ryan P A
2003-01-15
Collins' method of interpolating a potential energy surface (PES) from quantum chemical calculations for reactive systems (Jordan, M. J. T.; Thompson, K. C.; Collins, M. A. J. Chem. Phys. 1995, 102, 5647. Thompson, K. C.; Jordan, M. J. T.; Collins, M. A. J. Chem. Phys. 1998, 108, 8302. Bettens, R. P. A.; Collins, M. A. J. Chem. Phys. 1999, 111, 816) has been applied to a bound state problem. The interpolation method has been combined for the first time with quantum diffusion Monte Carlo calculations to obtain an accurate ground state zero-point energy, the vibrationally average rotational constants, and the vibrationally averaged internal coordinates. In particular, the system studied was fluoromethane using a composite method approximating the QCISD(T)/6-311++G(2df,2p) level of theory. The approach adopted in this work (a) is fully automated, (b) is fully ab initio, (c) includes all nine nuclear degrees of freedom, (d) requires no assumption of the functional form of the PES, (e) possesses the full symmetry of the system, (f) does not involve fitting any parameters of any kind, and (g) is generally applicable to any system amenable to quantum chemical calculations and Collins' interpolation method. The calculated zero-point energy agrees to within 0.2% of its current best estimate. A0 and B0 are within 0.9 and 0.3%, respectively, of experiment.
Rovibrational bound states of SO{sub 2} isotopologues. I: Total angular momentum J = 0–10
Energy Technology Data Exchange (ETDEWEB)
Kumar, Praveen, E-mail: Praveen.Kumar@ttu.edu; Ellis, Joseph; Poirier, Bill, E-mail: Bill.Poirier@ttu.edu
2015-04-01
Highlights: • We report calculation of the exact rovibrational energy levels of SO{sub 2} for J = 0–10. • We report sulfur isotope shifts of the SO{sub 2} isotopologues rovibrational frequencies. • Coriolis coupling is treated exactly. • All rovibrational levels are computed to a high level of numerical convergence. • All of the rovibrational data exhibit near-perfect mass-dependent fractionation. - Abstract: Isotopic variation of the rovibrational bound states of SO{sub 2} for the four stable sulfur isotopes {sup 32–34,36}S is investigated in comprehensive detail. In a two-part series, we compute the low-lying energy levels for all values of total angular momentum in the range J = 0–20. All rovibrational levels are computed, to an extremely high level of numerical convergence. The calculations have been carried out using the ScalIT suite of parallel codes. The present study (Paper I) examines the J = 0–10 rovibrational levels, providing unambiguous symmetry and rovibrational label assignments for each computed state. The calculated vibrational energy levels exhibit very good agreement with previously reported experimental and theoretical data. Rovibrational energy levels, calculated without any Coriolis approximations, are reported here for the first time. Among other potential ramifications, this data will facilitate understanding of the origin of mass-independent fractionation of sulfur isotopes in the Archean rock record—of great relevance for understanding the “oxygen revolution”.
Liu, De-Yin; Tian, Bo; Xie, Xi-Yang
2017-03-01
Bound-state vector soliton solutions for the coupled variable-coefficient higher-order nonlinear Schrödinger equations, which describe the simultaneous propagation of nonlinear waves in the inhomogeneous optical fiber, are investigated. Introducing auxiliary functions, we derive the bilinear forms and corresponding constraints on the variable coefficients. Through symbolic computation, we construct the one- and two-soliton solutions. We see that the variable coefficients in the equations affect the soliton structures. With different choices of the variable coefficients, we obtain the cubic, periodic, and parabolic solitons. Bound-state solitons and interactions are analyzed graphically.
Oades, G C; Matsinos, E; Rasche, G; Woolcock, W S
2007-01-01
We give the conversion equations which lead from experimental values of the 3p -> 1s transition energy in pionic hydrogen and the total width of the 1s level to values of the s-wave threshold scattering parameters for the processes pi- p -> pi- p and pi- p -> pi0 n respectively. Using a three-channel potential model, we then calculate the electromagnetic corrections to these quantities, which remove the effects of the Coulomb interaction, the external mass differences and the presence of the gamma n channel. We give the s-wave scattering parameters obtained from the present experimental data and these electromagnetic corrections. Finally we discuss the implications for isospin invariance.
Gashi, A; Oades, G C; Rasche, G; Woolcock, W S
2000-01-01
Using newly calculated electromagnetic corrections, we have made a phase shift analysis of experimental data on pi+/- p elastic scattering up to 100 MeV, assuming the effective hadronic interaction to be isospin invariant. The output consists of parametrised s and p-wave hadronic phases for isospin 1/2 and 3/2. It is not possible to fit the charge exchange data satisfactorily. We give values for the s-wave scattering lengths and effective ranges and for the p-wave scattering volumes. The combinations 2a_1 + a_3 and a_1 - a_3 of s-wave scattering lengths extracted from pionic hydrogen data are compared with those obtained from our analysis.
2002-01-01
This experiment uses a magnetic spectrometer to search for monoenergetic @g and @p@+ transitions between bound N&bar.N states. The spectrometer is instrumented with drift chambers (NDC, RDC and PDC), proportional wire chambers (A-E), and various thin scintillation counters (S,M,G,AH,V,Q,D,E and PH) f purposes, as shown in the accompanying drawing.\\\\ \\\\ Gamma-rays produced in the LH^2 target are materialized by a 10\\% converter located in the B chamber with an acceptance (@D@W/4@p) of @=2-6x10|-|3 (100-400 MeV) and 6x10|-|3 ($>$400 MeV). Trajectories of bent electron-positron pairs and @p@+ are measured in the A-E~chambers. Trajectories of less frequent high energy penetrating tracks, as well as the remaining associated charged annihilation products exiting the target, are measured in the drift chamber system. \\\\ \\\\ The resultant energy resolution (@DE/E) is better than 1,5\\% R.M.S. over the full range of energies studied. To illustrate the sensitivity of this experiment, a @g line at 300 MeV produced at t...
Girish, Tavarekere S; Gopal, Balasubramanian
2010-09-17
Proteases belonging to the M20 family are characterized by diverse substrate specificity and participate in several metabolic pathways. The Staphylococcus aureus metallopeptidase, Sapep, is a member of the aminoacylase-I/M20 protein family. This protein is a Mn(2+)-dependent dipeptidase. The crystal structure of this protein in the Mn(2+)-bound form and in the open, metal-free state suggests that large interdomain movements could potentially regulate the activity of this enzyme. We note that the extended inactive conformation is stabilized by a disulfide bond in the vicinity of the active site. Although these cysteines, Cys(155) and Cys(178), are not active site residues, the reduced form of this enzyme is substantially more active as a dipeptidase. These findings acquire further relevance given a recent observation that this enzyme is only active in methicillin-resistant S. aureus. The structural and biochemical features of this enzyme provide a template for the design of novel methicillin-resistant S. aureus-specific therapeutics.
Yarmukhamedov, R
2016-01-01
Asymptotic expressions for the radial and full wave functions of a three{body bound halo nuclear system with two charged particles in relative coordinates are obtained in explicit form, when the relative distance between two particles tends to infinity. The obtained asymptotic forms are applied to the analysis of the asymptotic behavior of the three-body (pn?) wave functions for the halo ($E^*=3.562$ MeV, $J^{\\pi}=0^+$, $T=1$) state of $^6$Li derived by D. Baye within the Lagrange-mesh method for two forms of the $\\alpha N$ -potential. The agreement between the calculated wave function and the asymptotic formula is excellent for distances up to 30 fm. Information about the values of the three-body asymptotic normalization functions is extracted. It is shown that the extracted values of the three-body asymptotic normalization function are sensitive to the form of the $\\alpha N$ -potential. The mirror symmetry is revealed for the three-body asymptotic normalization functions derived for the isobaric ($^6$He, $^...
Energy Technology Data Exchange (ETDEWEB)
Christiansen, H.R. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]. E-mail: hugo@cbpf.br; Cima, O.M. Del [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica]. E-mail: delcima@gft.ucp.br; Ferreira Junior, M.M. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]|[Maranhao Univ., Sao Luis, MA (Brazil). Dept. de Fisica]. E-mail: manojr@cbpf.br; Helayel-Neto, J.A. [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]. E-mail: helayel@gft.ucp.br
2001-08-01
We consider a parity-preserving QED{sub 3} model with spontaneous breaking of the gauge symmetry as a framework for the evaluation of the electron-electron interaction potential underlying high-T{sub e} superconductivity. The fact that resulting potential, - C{sub s} K{sub o} (Mr), is non-confining and weak (in the sense of Kato) strongly suggests the mechanism of pair-condensation. This potential, compatible with an s-wave order parameters, is then applied to the Schrodinger equation for the sake of numerical calculations, thereby enforcing the existence of bound states. The results worked out by means of our theoretical framework are checked by considering a number of phenomenological data extracted from different copper oxide superconductors. The agreement may motivate a deeper analysis of our model viewing an application to quasi-planar cuprate superconductors. The data analyzed here suggest an energy scale of 1-10 meV for the breaking of the U(1)-symmetry. (author)
I(-)·(CH3I)2 photoexcitation: the influence of dipole bound states on detachment and fragmentation.
Van Duzor, Matthew; Mbaiwa, Foster; Lasinski, Joshua; Holtgrewe, Nicholas; Mabbs, Richard
2011-06-01
We present the results of a photoelectron imaging study of the I(-)·(CH(3)I)(2) cluster anion over excitation wavelengths 355-260 nm. The resulting spectra and photoelectron angular distributions (PADs) suggest extensive electron-molecule interaction following photoexcitation. Fragmentation channels are observed subsequent to excitation between 355 and 330 nm. The origin of these features, which begin 200 meV and peak 70 meV below the X band direct detachment threshold, is described in terms of a predissociative dipole bound state. The nature of the fragments detected and the energetics of the channel opening argue strongly in favor of an asymmetric, head to tail cluster anion geometry posited by Dessent et al. [Acc. Chem. Res. 31, 527 (1998)]. Above the direct detachment threshold, PADs display evidence of phenomena akin to electron-molecule scattering. The fragment anions disappear above the X band threshold but reappear some distance below the second (A) direct detachment band. At these energies there is also rapid variation of the X band PAD, an observation attributed to autodetachment via spin-orbit relaxation of the iodine core of the cluster.
I-.(CH3I)2 photoexcitation: The influence of dipole bound states on detachment and fragmentation
Van Duzor, Matthew; Mbaiwa, Foster; Lasinski, Joshua; Holtgrewe, Nicholas; Mabbs, Richard
2011-06-01
We present the results of a photoelectron imaging study of the I-.(CH3I)2 cluster anion over excitation wavelengths 355-260 nm. The resulting spectra and photoelectron angular distributions (PADs) suggest extensive electron-molecule interaction following photoexcitation. Fragmentation channels are observed subsequent to excitation between 355 and 330 nm. The origin of these features, which begin 200 meV and peak 70 meV below the X band direct detachment threshold, is described in terms of a predissociative dipole bound state. The nature of the fragments detected and the energetics of the channel opening argue strongly in favor of an asymmetric, head to tail cluster anion geometry posited by Dessent et al. [Acc. Chem. Res. 31, 527 (1998)], 10.1021/ar950061f. Above the direct detachment threshold, PADs display evidence of phenomena akin to electron-molecule scattering. The fragment anions disappear above the X band threshold but reappear some distance below the second (A) direct detachment band. At these energies there is also rapid variation of the X band PAD, an observation attributed to autodetachment via spin-orbit relaxation of the iodine core of the cluster.
Davlieva, Milya; Donarski, James; Wang, Jiachen; Shamoo, Yousif; Nikonowicz, Edward P
2014-01-01
Several protein-targeted RNA aptamers have been identified for a variety of applications and although the affinities of numerous protein-aptamer complexes have been determined, the structural details of these complexes have not been widely explored. We examined the structural accommodation of an RNA aptamer that binds bacterial r-protein S8. The core of the primary binding site for S8 on helix 21 of 16S rRNA contains a pair of conserved base triples that mold the sugar-phosphate backbone to S8. The aptamer, which does not contain the conserved sequence motif, is specific for the rRNA binding site of S8. The protein-free RNA aptamer adopts a helical structure with multiple non-canonical base pairs. Surprisingly, binding of S8 leads to a dramatic change in the RNA conformation that restores the signature S8 recognition fold through a novel combination of nucleobase interactions. Nucleotides within the non-canonical core rearrange to create a G-(G-C) triple and a U-(A-U)-U quartet. Although native-like S8-RNA interactions are present in the aptamer-S8 complex, the topology of the aptamer RNA differs from that of the helix 21-S8 complex. This is the first example of an RNA aptamer that adopts substantially different secondary structures in the free and protein-bound states and highlights the remarkable plasticity of RNA secondary structure.
Zero-energy states bound to a magnetic {pi}-flux vortex in a two-dimensional topological insulator
Energy Technology Data Exchange (ETDEWEB)
Mesaros, Andrej, E-mail: andrej.mesaros@bc.edu [Department of Physics, Boston College, Chestnut Hill, MA 02467 (United States); Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden (Netherlands); Slager, Robert-Jan; Zaanen, Jan; Juricic, Vladimir [Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden (Netherlands)
2013-02-21
We show that the existence of a pair of zero-energy modes bound to a vortex carrying a {pi}-flux is a generic feature of the topologically non-trivial phase of the M-B model, which was introduced to describe the topological band insulator in HgTe quantum wells. We explicitly find the form of the zero-energy states of the corresponding Dirac equation, which contains a novel momentum-dependent mass term and describes a generic topological transition in a band insulator. The obtained modes are exponentially localized in the vortex-core, with the dependence of characteristic length on the parameters of the model matching the dependence extracted from a lattice version of the model. We consider in full generality the short-distance regularization of the vector potential of the vortex, and show that a particular choice yields the modes localized and simultaneously regular at the origin. Finally, we also discuss a realization of two-dimensional spin-charge separation through the vortex zero-modes.
Ghorbel, Imen; Amara, Ibtissem Ben; Ktari, Naourez; Elwej, Awatef; Boudawara, Ons; Boudawara, Tahia; Zeghal, Najiba
2016-12-01
Accumulation of aluminium and acrylamide in food is a major source of human exposure. Their adverse effects are well documented, but there is no information about the health problems arising from their combined exposure. The aim of the present study was to examine the possible neurotoxic effects after co-exposure of pregnant and lactating rats to aluminium and acrylamide in order to evaluate redox state, cholinergic function and membrane-bound ATPases in the cerebellum of adult rats and their progeny. Pregnant female rats have received aluminium (50 mg/kg body weight) via drinking water and acrylamide (20 mg/kg body weight) by gavage, either individually or in combination from the 14th day of pregnancy until day 14 after delivery. Exposure to these toxicants provoked an increase in malondialdehyde (MDA) and advanced oxidation protein product (AOPP) levels and a decrease in SOD, CAT, GPx, Na(+)K(+)-ATPase, Mg(2+)-ATPase and AChE activities in the cerebellum of mothers and their suckling pups. A reduction in GSH, NPSH and vitamin C levels was also observed. These changes were confirmed by histological results. Interestingly, co-exposure to these toxicants exhibited synergism based on physical and biochemical variables in the cerebellum of mothers and their progeny.
Institute of Scientific and Technical Information of China (English)
Eser Ol(g)ar
2009-01-01
We obtain the bound-state energy of the Klein-Gordon equation for some examples of quasi-exactly solvable potentials within the framework of asymptotic iteration method (AIM). The eigenvalues are calculated for type-1 solutions. The whole quasi-exactly solvable potentials are generated from the defined relation between the vector and scalar potentials.
Institute of Scientific and Technical Information of China (English)
张学骜; 陈柯; 段正路
2005-01-01
Solving the Klein-Gordon equation and Dirac equation with ring-shaped non-spherical oscillator gives the exact bound state wavefunction and energy equation, and the relations between non-relativistic Schrodinger equation, KleinGordon equation and Dirac equation with equal scalar and vector potentials.
Tsushima, K; Saitô, K; Thomas, A W; Lu, D H
2000-01-01
We discuss the effect of changes in meson properties in a nuclear medium on physical observables, notably, $J/\\Psi$ dissociation on pion and $\\rho$ meson comovers in relativistic heavy ion collisions, and the prediction of the $\\omega$-, $\\eta$- and $\\eta'$-nuclear bound states.