Ehrenfest time and the coherent backscattering off ballistic cavities

TL;DR

This paper investigates how the Ehrenfest time influences coherent backscattering in ballistic cavities, revealing both suppression of weak localization and the emergence of off-diagonal contributions to enhanced backscattering.

Contribution

It introduces the role of off-diagonal contributions to coherent backscattering when the Ehrenfest time is significant, extending previous understanding of quantum interference effects.

Findings

Weak localization correction is suppressed proportionally to exp(-tau_E/tau_D).

Quantum interference enhances reflection probability by a factor of two.

Off-diagonal contributions to coherent backscattering become relevant with non-negligible Ehrenfest time.

Abstract

If the Ehrenfest time tau_E of a ballistic cavity is not negligible in comparison to its dwell time tau_D, the weak localization correction to the cavity's transmission is suppressed proportional to exp(-tau_E/tau_D). At the same time, quantum interference enhances the probability of reflection into the mode of incidence by a factor two. This `enhanced backscattering' does not depend on the Ehrenfest time. We show that, in addition to the diagonal enhanced backscattering, there are off-diagonal contributions to coherent backscattering that become relevant if the Ehrenfest time is not negligible.