Localization due to interaction-enhanced disorder in bosonic systems

TL;DR

This paper demonstrates that in bosonic systems without single-particle localization, interactions can induce localization through interaction-enhanced disorder, supported by analytical and numerical evidence.

Contribution

It introduces a bosonic model where interactions cause localization in the absence of single-particle localization, revealing a new mechanism for many-body localization.

Findings

Interactions enhance weak disorder leading to localization.

Localization occurs due to interactions, not despite them.

Analytical and numerical results support the localization mechanism.

Abstract

Localization in interacting systems caused by disorder, known as many-body localization (MBL), has attracted a lot of attention in recent years. Most systems studied in this context also show single-particle localization, and the question of MBL is whether the phenomena survives the effects of interactions. It is intriguing to consider a system with no single-particle localization but which does localize in the presence of many particles. The localization phenomena occurs "due to" rather than "in spite of" interactions in such systems. We consider a simple bosonic system and show that interactions enhance the effects of very weak disorder and result in localization when many particles are present. We provide physical insights into the mechanism involved and support our results with analytical and numerical calculations.