Enhancement in breaking of time-reversal invariance in the quantum kicked rotor.

Agrawal, Ramgopal; Pandey, Akhilesh; Puri, Sanjay · Phys Rev E · 2021

basic_science · Level V

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Abstract

We study the breaking of time-reversal invariance (TRI) by the application of a magnetic field in the quantum kicked rotor (QKR), using Izrailev's finite-dimensional model. There is a continuous crossover from TRI to time-reversal noninvariance (TRNI) in the spectral and eigenvector fluctuations of the QKR. We show that the properties of this TRI to TRNI transition depend on α^{2}/N, where α is the chaos parameter of the QKR and N is the dimensionality of the evolution operator matrix. For α^{2}/N≳N, the transition coincides with that in random matrix theory. For α^{2}/N<N, the transition shows a marked deviation from random matrix theory. Further, the speed of this transition as a function of the magnetic field is significantly enhanced as α^{2}/N decreases.