Universal transport in periodically driven systems without long-lived quasiparticles

TL;DR

This paper demonstrates that universal topological charge transport persists in strongly interacting periodically driven systems, even when quasiparticles are short-lived, by analyzing conditions for a quasisteady state and supporting findings with numerical simulations.

Contribution

It shows that topological transport in driven systems remains robust beyond weak interactions, establishing a new understanding of far-from-equilibrium topological phenomena.

Findings

Universal transport persists in strongly interacting regimes.

Current is insensitive to interaction-induced band changes under certain conditions.

Numerical simulations confirm the theoretical predictions.

Abstract

An intriguing regime of universal charge transport at high entropy density has been proposed for periodically driven interacting one-dimensional systems with Bloch bands separated by a large single-particle band gap. For weak interactions, a simple picture based on well-defined Floquet quasiparticles suggests that the system should host a quasisteady state current that depends only on the populations of the system's Floquet-Bloch bands and their associated quasienergy winding numbers. Here we show that such topological transport persists into the strongly interacting regime where the single-particle lifetime becomes shorter than the drive period. Analytically, we show that the value of the current is insensitive to interaction-induced band renormalizations and lifetime broadening when certain conditions are met by the system's non-equilibrium distribution function. We show that these conditions correspond to a quasisteady state. We support these predictions through numerical simulation of a system of strongly interacting fermions in a periodically-modulated chain of Sachdev-Ye-Kitaev dots. Our work establishes universal transport at high entropy density as a robust far from equilibrium topological phenomenon, which can be readily realized with cold atoms in optical lattices.