Anisotropic pair-superfluidity of trapped two-component Bose gases

TL;DR

This paper theoretically explores the phase diagram of two-component ultracold Bose gases with negative inter-species interactions, revealing the stability and fragility of the pair-superfluid phase under various conditions.

Contribution

It provides a detailed phase diagram for pair-superfluidity in two-component Bose gases using Bosonic Dynamical Mean-Field Theory, including effects of asymmetry and trapping.

Findings

Pair-superfluidity is stable at zero and finite temperature for symmetric populations.

Asymmetric hopping preserves the pair-superfluid phase.

Small population imbalances destroy the pair-superfluid phase.

Abstract

We theoretically investigate the pair-superfluid phase of two-component ultracold gases with negative inter-species interactions in an optical lattice. We establish the phase diagram for filling $n=1$ at zero and finite temperature, by applying Bosonic Dynamical Mean-Field Theory, and confirm the stability of pair-superfluidity for asymmetric hopping of the two species. While the pair superfluid is found to be robust in the presence of a harmonic trap, we observe that it is destroyed already by a small population imbalance of the two species.