Many-body localization for randomly interacting bosons

TL;DR

This paper investigates many-body localization in a one-dimensional bosonic system with randomly varying interactions, revealing an inverted mobility edge and characterizing the transition between localized and delocalized states through numerical and analytical methods.

Contribution

It introduces a model of bosons with random interactions in 1D and demonstrates the existence of an inverted mobility edge using numerical simulations and analytical predictions.

Findings

Existence of an inverted mobility edge with mobile particles at the lower spectrum edge

Level spacing analysis characterizes the localized-delocalized transition

Large system simulations confirm the mobility edge and long-term behavior

Abstract

We study many-body localization in a one dimensional optical lattice filled with bosons. The interaction between bosons is assumed to be random, which can be realized for atoms close to a microchip exposed to a spatially fluctuating magnetic field. Close to a Feshbach resonance, such controlled fluctuations can be transfered to the interaction strength. We show that the system reveals an inverted mobility edge, with mobile particles at the lower edge of the spectrum. A statistical analysis of level spacings allows us to characterize the transition between localized and excited states. The existence of the mobility edge is confirmed in large systems, by time dependent numerical simulations using tDMRG. A simple analytical model predicts the long time behavior of the system.