Mixed bubbles in Bose-Bose mixtures

TL;DR

This paper predicts a novel mixed-bubble phase in Bose-Bose mixtures caused by beyond-mean-field effects, occurring under specific conditions of mass or coupling disparities, with implications for experimental realization.

Contribution

It introduces the concept of mixed bubbles in Bose-Bose mixtures, a phenomenon arising from beyond-mean-field effects due to mass or coupling asymmetries.

Findings

Mixed-bubble regime exists in all dimensions.

Conditions depend on mass and intraspecies coupling differences.

Implications for current experimental setups.

Abstract

Repulsive Bose-Bose mixtures are known to either mix or phase-separate into pure components. Here we predict a mixed-bubble regime in which bubbles of the mixed phase coexist with a pure phase of one of the components. This is a beyond-mean-field effect which occurs for unequal masses or unequal intraspecies coupling constants and is due to a competition between the mean-field term, quadratic in densities, and a nonquadratic beyond-mean-field correction. We find parameters of the mixed-bubble regime in all dimensions and discuss implications for current experiments.