Dynamics of fluctuation correlation in a periodically driven classical system

Physical review. B./Physical review. B, vol. 104

Abstract

A many-body interacting system of classical kicked rotor serves as a prototypical model for studying Floquet heating dynamics. Having established the fact that this system exhibits a long-lived prethermal phase with a quasiconserved average Hamiltonian before entering into the chaotic heating regime, we use spatiotemporal fluctuation correlation of kinetic energy as a two-point observable to probe the above dynamic phases. We remarkably find the diffusive transport of fluctuation in the prethermal regime suggesting an underlying hydrodynamic picture in a generalized Gibbs ensemble with a definite temperature that depends on the driving parameter and the initial conditions. On the other hand, the heating regime is characterized by a diffusive growth of kinetic energy where the correlation is sharply localized around the fluctuation center for all time. Consequently, we attribute nondiffusive and nonlocalized structure of correlation to the crossover regime, connecting the prethermal phase to the heating phase, where the kinetic energy displays a complicated growth structure. We understand these numerical findings using the notion of relative phase matching where the prethermal phase (heating regime) refers to an effectively coupled (isolated) nature of the rotors. We exploit the statistical uncorrelated nature of the angles of the rotors in the heating regime to find the analytical form of the correlator that mimics our numerical results in a convincing way.

Authors 3

1. Aritra Kundu

   Scuola Internazionale Superiore di Studi Avanzati · Istituto Nazionale di Fisica Nucleare, Sezione di Trieste

   Affiliation as printed

   SISSA and INFN via Bonomea 265, 34136 Trieste, Italy

2. Atanu Rajak

   Presidency University

   Affiliation as printed

   Presidency University, 86/1, College Street, Kolkata 700073, India

3. Tanay Nag Aachen Institute für Theorie der Statistischen Physik

   RWTH Aachen University

   Affiliation as printed

   Institute für Theorie der Statistischen Physik, RWTH Aachen University, 52056 Aachen, Germany