Transport in Stark Many Body Localized Systems

TL;DR

This study investigates transport properties in an interacting spin chain under strong electric fields, revealing transient localization effects and the conditions under which true Stark many-body localization occurs.

Contribution

It demonstrates that genuine Stark many-body localization only exists in the thermodynamic limit and introduces a Magnus expansion approach for finite systems.

Findings

Localization persists only up to a finite time depending on system size and field strength

Transient localization can be approximated by a Magnus expansion for strong fields

True Stark MBL likely occurs only in the thermodynamic limit

Abstract

Using numerically exact methods we study transport in an interacting spin chain which for sufficiently strong spatially constant electric field is expected to experience Stark many-body localization. We show that starting from a generic initial state, a spin-excitation remains localized only up to a finite delocalization time, which depends exponentially on the size of the system and the strength of the electric field. This suggests that bona fide Stark many-body localization occurs only in the thermodynamic limit. We also demonstrate that the transient localization in a finite system and for electric fields stronger than the interaction strength can be well approximated by a Magnus expansion up-to times which grow with the electric field strength.