Many body localization in the presence of a central qudit

TL;DR

This paper investigates how many-body localization persists when a localized system is globally coupled to a central multi-level quantum system, revealing conditions under which localization survives or breaks down, and exploring long-range interactions.

Contribution

It introduces a model of many-body localization with a central qudit and analyzes conditions for localization persistence and thermalization phases.

Findings

Localized phase survives under certain scaling of system size and qudit dimension.

Two thermalizing phases identified depending on qudit ergodicity.

First example of MBL with long-range, non-confining interactions.

Abstract

We consider a many-body localized system coupled globally to a central $d$-level system. Under an appropriate scaling of $d$ and $L$, we find evidence that the localized phase survives. We argue for two possible thermalizing phases, depending on whether the qudit becomes fully ergodic. This system provides one of the first examples of many-body localization in the presence of long-range (non-confining) interactions.