Disordered Supersolids in the Extended Bose-Hubbard Model

TL;DR

This study uses quantum Monte Carlo simulations to explore how disorder affects the supersolid phase in the extended Bose-Hubbard model, revealing both suppression and enhancement of critical temperatures under different conditions.

Contribution

It provides the first detailed analysis of disorder effects on supersolids in the extended Bose-Hubbard model on a cubic lattice.

Findings

Disorder generally suppresses the supersolid critical temperature.

A narrow parameter window exists where disorder enhances the supersolid critical temperature.

Supersolids can survive moderate disorder and thermal fluctuations.

Abstract

The extended Bose-Hubbard model captures the essential properties of a wide variety of physical systems including ultracold atoms and molecules in optical lattices, Josephson junction arrays, and certain narrow band superconductors. It exhibits a rich phase diagram including a supersolid phase where a lattice solid coexists with a superfluid. We use quantum Monte Carlo to study the supersolid part of the phase diagram of the extended Bose-Hubbard model on the simple cubic lattice. We add disorder to the extended Bose-Hubbard model and find that the maximum critical temperature for the supersolid phase tends to be suppressed by disorder. But we also find a narrow parameter window in which the supersolid critical temperature is enhanced by disorder. Our results show that supersolids survive a moderate amount of spatial disorder and thermal fluctuations in the simple cubic lattice.