Bose Hubbard model in the presence of Ohmic dissipation

TL;DR

This paper investigates how Ohmic dissipation affects the phase diagram of the Bose-Hubbard model at zero temperature, revealing modifications to superfluid regions and the conditions for superfluidity.

Contribution

It introduces a mean-field analysis of the Bose-Hubbard model with local bath coupling that conserves on-site occupation, highlighting the impact on phase boundaries and superfluidity.

Findings

Bath coupling renormalizes chemical potential and interactions.

Reduces superfluid region size between Mott lobes.

Finite hopping needed for superfluidity at degeneracy points.

Abstract

We study the zero temperature mean-field phase diagram of the Bose-Hubbard model in the presence of local coupling between the bosons and an external bath. We consider a coupling that conserves the on-site occupation number, preserving the robustness of the Mott and superfluid phases. We show that the coupling to the bath renormalizes the chemical potential and the interaction between the bosons and reduces the size of the superfluid regions between the insulating lobes. For strong enough coupling, a finite value of hopping is required to obtain superfluidity around the degeneracy points where Mott phases with different occupation numbers coexist. We discuss the role that such a bath coupling may play in experiments that probe the formation of the insulator-superfluid shell structure in systems of trapped atoms.