Critical velocity of flowing supersolids of dipolar Bose gases in optical lattices

TL;DR

This paper investigates the superfluidity of supersolid phases in dipolar Bose gases within optical lattices, revealing a lower critical velocity compared to conventional superfluids and proposing its use as an experimental signature.

Contribution

It provides a linear stability analysis of supersolid superflow in a dipolar Bose-Hubbard model, identifying the critical velocity as a key experimental indicator.

Findings

Supersolids can sustain superflow up to a critical velocity.

Critical velocity in supersolids is smaller than in superfluids.

Critical velocity can serve as an experimental signature of supersolidity.

Abstract

We study superfluidity of supersolid phases of dipolar Bose gases in two-dimensional optical lattices. We perform linear stability analyses for the corresponding dipolar Bose-Hubbard model in the hardcore boson limit to show that a supersolid can have stable superflow until the flow velocity reaches a certain critical value. The critical velocity for the supersolid is found to be significantly smaller than that for a conventional superfluid phase. We propose that the critical velocity can be used as a signature to identify the superfluidity of the supersolid phase in experiment.