Lattice supersolid phase of strongly correlated bosons in an optical cavity

TL;DR

This paper uses numerical simulations to explore a generalized Bose-Hubbard model with cavity-mediated interactions, revealing new self-organized quantum phases like lattice supersolid and checkerboard solid, influenced by temperature and trapping.

Contribution

It introduces a comprehensive phase diagram for strongly correlated bosons in a cavity, identifying two novel self-organized phases and analyzing their stability under various conditions.

Findings

Discovery of lattice supersolid and checkerboard solid phases.

Thermal fluctuations enhance self-organized phases.

Stable phases persist under strong s-wave scattering.

Abstract

We numerically simulate strongly correlated ultracold bosons coupled to a high-finesse cavity field, pumped by a laser beam in the transverse direction. Assuming a weak classical optical lattice added in the cavity direction, we model this system by a generalized Bose-Hubbard model, which is solved by means of bosonic dynamical mean-field theory. The complete phase diagram is established, which contains two novel self-organized quantum phases, lattice supersolid and checkerboard solid, in addition to conventional phases such as superfluid and Mott insulator. At finite but low temperature, thermal fluctuations are found to enhance the buildup of the self-organized phases. We demonstrate that cavity-mediated long-range interactions can give rise to stable lattice supersolid and checkerboard solid phases even in the regime of strong s-wave scattering. In the presence of a harmonic trap, we discuss coexistence of these self-organized phases, as relevant to experiments.