Distinctive response of many-body localized systems to strong electric field

TL;DR

This paper investigates the unique response of many-body localized systems to strong electric fields, revealing nonergodic behavior characterized by persistent oscillations and logarithmic energy growth, distinguishing them from ergodic systems.

Contribution

It demonstrates that MBL systems exhibit distinctive oscillatory and logarithmic energy growth responses under strong driving, highlighting their nonergodic nature and robustness of localization features.

Findings

Oscillations with frequency independent of driving strength

Damped oscillations due to dephasing, not heating

Logarithmic increase of energy and polarization over time

Abstract

We study systems which are close to or within the many-body localized (MBL) regime and are driven by strong electric field. In the ergodic regime, the disorder extends applicability of the equilibrium linear--response theory to stronger drivings, whereas the response of the MBL systems is very distinctive, revealing currents with damped oscillations. The oscillation frequency is independent of driving and the damping is not due to heating but rather due to dephasing. The details of damping depend on the system's history reflecting nonergodicity of the MBL phase, while the frequency of the oscillations remains a robust hallmark of localization. We show that the distinctive characteristic of the driven MBL phase is also a logarithmic increase of the energy and the polarization with time.