Many-Body Localization in a Quasiperiodic System

TL;DR

This paper provides numerical evidence that many-body localization can occur in one-dimensional quasiperiodic systems without disorder, highlighting a transition from localized to ergodic phases influenced by interactions.

Contribution

It demonstrates that many-body localization transitions occur in quasiperiodic systems, extending the understanding beyond disordered models and connecting single-particle and many-body localization.

Findings

Many-body localization occurs in quasiperiodic systems without disorder.

Interactions induce a transition from localized to ergodic phases.

Results are relevant for cold atom and nonlinear light experiments.

Abstract

Recent theoretical and numerical evidence suggests that localization can survive in disordered many-body systems with very high energy density, provided that interactions are sufficiently weak. Stronger interactions can destroy localization, leading to a so-called many-body localization transition. This dynamical phase transition is relevant to questions of thermalization in extended quantum systems far from the zero-temperature limit. It separates a many-body localized phase, in which localization prevents transport and thermalization, from a conducting ("ergodic") phase in which the usual assumptions of quantum statistical mechanics hold. Here, we present numerical evidence that many-body localization also occurs in models without disorder but rather a quasiperiodic potential. In one dimension, these systems already have a single-particle localization transition, and we show that this transition becomes a many-body localization transition upon the introduction of interactions. We also comment on possible relevance of our results to experimental studies of many-body dynamics of cold atoms and non-linear light in quasiperiodic potentials.