Dissipative Superfluidity in a Molecular Bose-Einstein Condensate

TL;DR

This paper develops a theory showing that weak dissipation can induce superfluidity in a molecular Bose-Einstein condensate, even without repulsive interactions, and discusses experimental implications.

Contribution

It introduces a novel dissipative superfluid transport theory and demonstrates that weak two-body loss can induce phase rigidity in a BEC without repulsive interactions.

Findings

Weak dissipation induces superfluid transport.

Dissipation enhances stability of dipolar molecular BEC.

A generalized $f$-sum rule applies to dissipative superfluids.

Abstract

Motivated by recent experimental realization of a Bose-Einstein condensate (BEC) of dipolar molecules, we develop superfluid transport theory for a dissipative BEC to show that a weak uniform two-body loss can induce phase rigidity, leading to superfluid transport of bosons even without repulsive interparticle interactions. A generalized $f$-sum rule is shown to hold for a dissipative superfluid as a consequence of weak U(1) symmetry. We also demonstrate that dissipation enhances the stability of a molecular BEC with dipolar interactions. Possible experimental signature of dissipative superfluidity are discussed.