Ultracold atoms in optical lattices with random on-site interactions

TL;DR

This paper investigates how disordered on-site interactions in lattice bosons affect their phase diagram, revealing shrinking Mott-insulating regions, stability of superfluid and Mott insulator phases, and potential experimental realizations with ultracold atoms.

Contribution

It introduces the effects of random on-site interactions on lattice bosons, highlighting qualitative changes in phase behavior not previously explored.

Findings

Mott-insulating regions shrink and vanish with increasing disorder

Superfluid and Mott insulator phases remain stable against Bose glass formation at low chemical potentials

Potential for experimental realization with ultracold atoms in optical lattices

Abstract

We consider the physics of lattice bosons affected by disordered on-site interparticle interactions. Characteristic qualitative changes in the zero temperature phase diagram are observed when compared to the case of randomness in the chemical potential. The Mott-insulating regions shrink and eventually vanish for any finite disorder strength beyond a sufficiently large filling factor. Furthermore, at low values of the chemical potential both the superfluid and Mott insulator are stable towards formation of a Bose glass leading to a possibly non-trivial tricritical point. We discuss feasible experimental realizations of our scenario in the context of ultracold atoms on optical lattices.