arXiv subjects

Shiro Kawabata

Publications and source records attributed to Shiro Kawabata.

79 records · Page 5Linked to original sources

arXiv2000

h/2e oscillations and quantum chaos in ballistic Aharonov-Bohm billiards

We study the quantum interference effect for the single ballistic Aharonov-Bohm billiard in the presence of a weak magnetic field B. The diagonal part of the wave-number averaged reflection coefficient $δ{\cal R}_D$ is calculated by use of semi-classical scattering theory. In addition to the appearance of "h/2e oscillation" that are caused by interference between time-reversed coherent backscattering classical trajectories, B in the conducting region leads to negative magnetoresistance and dampening of the h/2e oscillation amplitude. The B dependence of the results reflects the underlying classical (chaotic and regular) dynamics.

cond-mat.mes-hall↗

arXiv2000

Semiclassical theory of h/e Aharonov-Bohm oscillation for doubly connected ballistic cavities

In Aharonov-Bohm (AB) cavities forming doubly connected ballistic structures, h/e AB oscillations that result from the interference among the complicated trapped paths in the cavity can be described by the framework of the semiclassical theory. We derive formulas of the correlation function C(Δϕ) of the nonaveraged magnetoconductance for chaotic and regular AB cavities. The different higher harmonics behaviors for C(Δϕ) are related to the differing distribution of classical dwelling times. The AB oscillation in ballistic regimes provides an experimental probe of quantum signatures of classical chaotic and regular dynamics.

nlin.CD↗

arXiv1999

Berry phase induced persistent current in mesoscopic systems

Since the discovery of the Berry phase, there has been much interest in the study of topological effects in the fields of quantum mechanics and condensed matter physics. In this paper we investigate the persistent charge current in mesoscopic disorderd rings and compute the disorder averaged persistent current using the diagrammatic method. We find that within the adiabatic regime the average current oscillates as a function of the geometric flux which is related to the Berry phase.

cond-mat.mes-hall↗

arXiv1999

Semiclassical Theory of h/e Aharonov-Bohm Oscillation in Ballistic Regimes

We study the magneto-transport in Aharonov-Bohm (AB) billiards forming doubly connected structures. In these systems, non-averaged conductance oscillates as a function of magnetic flux with period h/e. We derive formulas of the correlation function C of the magneto-conductance for chaotic and regular AB billiards by use of the semiclassical theory. The different higher harmonics behaviors for C are related to the differing distribution of classical dwelling times. The AB oscillation in ballistic regimes provides an experimental probe of quantum signatures of classical chaotic and regular dynamics.

chao-dyn↗

arXiv1999

Berry phase and persistent current in disordered mesoscopic rings

A novel quantum interference effect in disordered quasi-one-dimensional rings in the inhomogeneous magnetic field is reported. We calculate the canonical disorder averaged persistent current using the diagrammatic perturbation theory. It is shown that within the adiabatic regime the average current oscillates as a function of the geometric flux which is related to the Berry phase and the period becomes half the value of the case of a single one-dimensional ring. We also discuss the magnetic dephasing effect on the averaged current.

cond-mat.mes-hall↗

arXiv1999

Persistent Currents in Quantum Chaotic Systems

The persistent current of ballistic chaotic billiards is considered with the help of the Gutzwiller trace formula. We derive the semiclassical formula of a typical persistent current $I^{typ}$ for a single billiard and an average persistent current $ $ for an ensemble of billiards at finite temperature. These formulas are used to show that the persistent current for chaotic billiards is much smaller than that for integrable ones. The persistent currents in the ballistic regime therefore become an experimental tool to search for the quantum signature of classical chaotic and regular dynamics.

cond-mat.mes-hall↗

arXiv1998

Chaos and quantum interference effect in semiconductor ballistic micro-structures

We study the quantum-interference effect in the ballistic Aharonov-Bohm (AB) billiard. The wave-number averaged conductance and the correlation function of the non-averaged conductance are calculated by use of semiclassical theory. Chaotic and regular AB billiards have turned out to lead to qualitatively different semiclassical formulas for the conductance with their behavior determined only by knowledge regarding the underlying classical scattering.

cond-mat.mes-hall↗