共查询到20条相似文献,搜索用时 15 毫秒
1.
J.-B. Liu J.-H. Li X.-Y. Lü A. Zheng 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):601-606
In this paper, we investigate the geometric phase of a composite system which is composed of two spin-
particles driven by a
time-varying magnetic field. Firstly, we consider the special case that only one subsystem driven by time-varying magnetic
field. Using the quantum jump
approach, we calculate the geometric phase associated with the adiabatic evolution of the system subjected to decoherence.
The results show that the lowest
order corrections to the phase in the no-jump trajectory is only quadratic in decoherence coefficient. Then, both subsystem
driven by time-varying magnetic
field is considered, we show that the geometric phase is related to the exchange-interaction coefficient and polar angle of
the magnetic field. 相似文献
2.
V.R. Khalilov 《Annals of Physics》2008,323(5):1280-1293
The scattering of spin-polarized electrons in an Aharonov-Bohm vector potential is considered. We solve the Pauli equation in 3 + 1 dimensions taking into account explicitly the interaction between the three-dimensional spin magnetic moment of electron and magnetic field. Expressions for the scattering amplitude and the cross section are obtained for spin-polarized electron scattered off a flux tube of small radius. It is also shown that bound electron states cannot occur in this quantum system. The scattering problem for the model of a flux tube of zero radius in the Born approximation is briefly discussed. 相似文献
3.
M.-M. He G. Chen J.-Q. Liang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):581-583
In this paper we investigate the Berry phase in Tavis-Cummings model in the
rotating wave approximation. The dipole-dipole interaction between the atoms
is considered. The eigenfunctions of the system are obtained and thus the
Berry phase is evaluated explicitly in terms of the introduction of the
phase shift. It is shown that the Berry phase can be easily controlled by
the atom-cavity coupling strength, the cavity frequency detuning, which can
be important in applications in geometric quantum computing. 相似文献
4.
J. Pade 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(2):345-350
For a modified Lennard-Jones interaction potential of the form ∼[(r0/r)2n-2-(r0/r)n], an exact and simple expression for the s-wave scattering length is presented, and discussed in some detail. For heavy alkali
atoms, which nowadays are routinely being employed to produce Bose-Einstein condensates, this potential is well compatible
with known experimental data when n = 6. 相似文献
5.
S. Banerjee R. Srikanth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):335-344
We study the geometric phase of an open two-level quantum
system under the influence of a squeezed, thermal environment for both
non-dissipative as well as dissipative system-environment
interactions. In the non-dissipative case, squeezing is found to have
a similar influence as temperature, of suppressing geometric phase,
while in the dissipative case, squeezing tends to counteract the
suppressive influence of temperature in certain regimes. Thus, an
interesting feature that emerges from our work is the contrast in the
interplay between squeezing and thermal effects in non-dissipative and
dissipative interactions. This can be useful for the practical
implementation of geometric quantum information processing. By
interpreting the open quantum effects as noisy channels, we make the
connection between geometric phase and quantum noise processes
familiar from quantum information theory. 相似文献
6.
M. Al Jaghoub 《The European Physical Journal A - Hadrons and Nuclei》2001,11(2):175-183
A relation linking the normalized s-wave scattering and the corresponding bound state wave functions at bound state poles is derived. This is done in the case
of a non-local, velocity-dependent Kisslinger potential. Using formal scattering theory, we present two analytical proofs
of the validity of the theorem. The first tackles the non-local potential directly, while the other transforms the potential
to an equivalent local but energy-dependent one. The theorem is tested both analytically and numerically by solving the Schr?dinger
equation exactly for the scattering and bound state wave functions when the Kisslinger potential has the form of a square
well. A first order approximation to the deviation from the theorem away from bound state poles is obtained analytically.
Furthermore, a proof of the analyticity of the Jost solutions in the presence of a non-local potential term is also given.
Received: 3 March 2001 / Accepted: 9 June 2001 相似文献
7.
De-Hone Lin 《Physics letters. A》2009,373(31):2634-2636
The analytic result of the Aharonov-Bohm effect for its influence on the oscillation of a two-dimensional charge density around a short range potential is given. Without losing generality, the cases of δ-function and hard disc potentials were examined. Numerical calculations show that the interferences among quantum particles are greatly influenced by the nonlocal effect, which leads to the modulation of phase and amplitude of the oscillation of charge density. Since the presence of a nonlocal influence of the Aharonov-Bohm effect on charged particles is universal, the results in the specific potentials examined are expected to appear also in other general systems which may be beneficial to the study of nanotechnology. 相似文献
8.
Q. Wang Y.-S. Zhang Y.-F. Huang G.-C. Guo 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):179-182
The generalized Hong-Ou-Mandel interferometer with anyons is studied. Novel interference results different from bosons or
fermions are found. An experimental scheme based on linear optics is proposed and realized to simulate the fourth-order interference
phenomenon of anyons. 相似文献
9.
In this Letter the approximately analytical scattering state solutions of the l-wave Schrödinger equation for the Manning-Rosen potential are carried out by a proper approximation to the centrifugal term. The normalized radial wave functions of l-wave scattering states are presented and the calculation formula of phase shifts is derived. It is well shown that the poles of the S-matrix in the complex energy plane correspond to bound states for real poles and scattering states for complex poles in the lower half of the energy plane. We consider and verify two special cases: the l=0 and the s-wave Hulthén potential. 相似文献
10.
G. De Chiara A. Łoziński G. M. Palma 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(1):179-183
The evolution of a two level system with a slowly varying Hamiltonian, modeled as a spin 1/2 in a slowly varying magnetic
field, and interacting with a quantum environment, modeled as a bath of harmonic oscillators is analyzed using a quantum Langevin
approach. This allows to easily obtain the dissipation time and the correction to the Berry phase in the case of an adiabatic
cyclic evolution. 相似文献
11.
H. T. Cui L. C. Wang X. X. Yi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):385-389
The geometric phase (GP) for bipartite systems in transverse
external magnetic fields is investigated in this paper. Two
different situations have been studied. We first consider two
non-interacting particles. The results show that because of
entanglement, the geometric phase is very different from that of the
non-entangled case. When the initial state is a Werner state, the
geometric phase is, in general, zero and moreover the singularity of
the geometric phase may appear with a proper evolution time.
We next study the
geometric phase when intra-couplings appear and choose Werner
states as the initial states to entail this discussion. The results
show that unlike our first case, the absolute value of the GP is not zero,
and attains its maximum when the rescaled coupling
constant J is less than 1. The effect of inhomogeneity of the
magnetic field is also discussed. 相似文献
12.
We solve the Klein–Gordon equation in the presence of a spatially one-dimensional cusp potential. The scattering solutions are obtained in terms of Whittaker functions and the condition for the existence of transmission resonances is derived. We show the dependence of the zero-reflection condition on the shape of the potential. In the low-momentum limit, transmission resonances are associated with half-bound states. We express the condition for transmission resonances in terms of the phase shifts. 相似文献
13.
M. P. Trushin A. L. Chudnovskiy 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(4):547-555
We have found a manifestation of spin-orbit Berry phase in the conductance
of a mesoscopic loop with Rashba spin-orbit coupling placed in an external magnetic field
perpendicular to the loop plane.
In detail, the transmission probabilities for a straight quantum wire
and for a quantum loop made of the same wire have been calculated and
compared with each other.
The difference between them has been investigated and identified with
a manifestation of spin-orbit Berry phase.
The non-adiabaticity effects at small radii of the loop have been found as well. 相似文献
14.
H. T. Cui Y. F. Zhang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(3):393-400
The pairwise entanglement, measured by concurrence and
geometric phase in high dimensional free-Fermion lattice systems
have been studied in this paper. When the system stays at the ground
state, their derivatives with the external parameter show the
singularity closed to the phase transition points, and can be used
to detect the phase transition in this model. Furthermore our
studies show for the free-Fermion model that both concurrence and
geometric phase show the intimate connection with the correlation
functions. The possible connection between concurrence and geometric
phase has been also discussed. 相似文献
15.
W.D. Heiss H.L. Harney 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(2):149-151
Exceptional points are singularities of the spectrum and wave functions of a Hamiltonian which occur as functions of a complex
interaction parameter. They are accessible in experiments with dissipative systems. We show that the wave function at an exceptional
point is a specific superposition of two configurations. The phase relation between the configurations is equivalent to a
chirality which should be detectable in an experiment.
Received 9 April 2001 and Received in final form 19 July 2001 相似文献
16.
M.I. Jaghoub 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):349-354
Using formal scattering theory, the scattering wave functions are extrapolated to negative energies corresponding to bound-state
poles. It is shown that the ratio of the normalized scattering and the corresponding bound-state wave functions, at a bound-state
pole, is uniquely determined by the bound-state binding energy. This simple relation is proved analytically for an arbitrary
angular momentum quantum number l > 0, in the presence of a velocity-dependent Kisslinger potential. The extrapolation relation is tested analytically by solving
the Schr?dinger equation in the p-wave case exactly for the scattering and the corresponding bound-state wave functions when the Kisslinger potential has the
form of a square well. A numerical resolution of the Schr?dinger equation in the p-wave case and of a square-well Kisslinger potential is carried out to investigate the range of validity of the extrapolated
connection. It is found that the derived relation is satisfied best at low energies and short distances.
Received: 17 October 2001 / Accepted: 4 January 2002 相似文献
17.
P. Gosselin A. Bérard H. Mohrbach 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(2):137-148
It has been recently found that the equations of motion of several
semiclassical systems must take into account terms arising from Berry phases
contributions. Those terms are responsible for the spin Hall effect in
semiconductor as well as the Magnus effect of light propagating in
inhomogeneous media. Intensive ongoing research on this subject seems to
indicate that a broad class of quantum systems may be affected by Berry
phase terms. It is therefore important to find a general procedure allowing
for the determination of semiclassical Hamiltonian with Berry Phase
corrections. This article presents a general diagonalization method at order
ħ for a large class of quantum Hamiltonians directly inducing Berry
phase corrections. As a consequence, Berry phase terms on both coordinates
and momentum operators naturally arise during the diagonalization procedure.
This leads to new equations of motion for a wide class of semiclassical
system. As physical applications we consider here a Dirac particle in an
electromagnetic or static gravitational field, and the propagation of a
Bloch electrons in an external electromagnetic field. 相似文献
18.
D. Bar L.P. Horwitz 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,25(4):505-518
We discuss the properties of a large number N of one-dimensional (bounded) locally periodic potential barriers in a finite interval. We show that the transmission coefficient,
the scattering cross section σ, and the resonances of σ depend sensitively upon the ratio of the total spacing to the total
barrier width. We also show that a time dependent wave packet passing through the system of potential barriers rapidly spreads
and deforms, a criterion suggested by Zaslavsky for chaotic behaviour. Computing the spectrum by imposing (large) periodic
boundary conditions we find a Wigner type distribution. We investigate also the S-matrix poles; many resonances occur for certain values of the relative spacing between the barriers in the potential.
Received 1st August 2001 and Received in final form 18 November 2001 相似文献
19.
We analyze how a short distance boundary condition for the Schrödinger equation must change as a function of the boundary radius by imposing the physical requirement of phase shift independence on the boundary condition. The resulting equation can be interpreted as a variable phase equation of a complementary boundary value problem. We discuss the corresponding infrared fixed points and the perturbative expansion around them generating a short distance modified effective range theory. We also discuss ultraviolet fixed points, limit cycles, and attractors with a given fractality which take place for singular attractive potentials at the origin. The scaling behavior of scattering observables can analytically be determined and is studied with some emphasis on the low energy nucleon-nucleon interaction via singular pion exchange potentials. The generalization to coupled channels is also studied. 相似文献
20.
J. Denschlag D. Cassettari A. Chenet S. Schneider J. Schmiedmayer 《Applied physics. B, Lasers and optics》1999,69(4):291-301
A large variety of trapping and guiding potentials can be designed by bringing cold atoms close to charged or current-carrying
material objects. Using a current-carrying wire we demonstrate how to build guides and traps for neutral atoms and using a
charged wire we study a 1/r
2 singularity. The simplicity and versatility of the principles demonstrated in our experiments will allow for miniaturization
and integration of atom optical elements into matter-wave quantum circuits.
Received: 13 December 1998 / Revised version: 8 July 1999 / Published online: 8 September 1999 相似文献