How periodic driving heats a disordered quantum spin chain

TL;DR

This paper investigates how periodic driving influences energy absorption in a disordered quantum spin chain, revealing distinct behaviors in ergodic, localized, and intermediate regimes through real-time analysis.

Contribution

It identifies characteristic signatures of ergodic and localized phases and uncovers an intermediate regime with logarithmic energy growth over extended periods.

Findings

Distinct fingerprints of ergodic and localized phases identified

Logarithmic energy growth observed in intermediate regime

Energy absorption behavior varies with driving frequency and disorder strength

Abstract

We study the energy absorption in real time of a disordered quantum spin chain subjected to coherent monochromatic periodic driving. We determine characteristic fingerprints of the well-known ergodic (Floquet-ETH for slow driving/weak disorder) and many-body localized (Floquet-MBL for fast driving/strong disorder) phases. In addition, we identify an intermediate regime, where the energy density of the system -- unlike the entanglement entropy a local and bounded observable -- grows logarithmically slowly over a very large time window.