Weakly-interacting Bose-Bose mixtures from the functional renormalisation group

TL;DR

This paper develops and applies the functional renormalisation group method to weakly-interacting Bose-Bose mixtures, analyzing thermodynamics, ground-state energies, and potential future research directions.

Contribution

It provides a comprehensive FRG framework for Bose-Bose mixtures and validates it through thermodynamic and polaron energy calculations.

Findings

Good agreement with existing thermodynamic data

Accurate ground-state energies for Bose polarons

Framework applicable to future Bose mixture studies

Abstract

We provide a detailed presentation of the functional renormalisation group (FRG) approach for weakly-interacting Bose-Bose mixtures, including a complete discussion on the RG equations. To test this approach, we examine thermodynamic properties of balanced three-dimensional Bose-Bose gases at zero and finite temperatures and find a good agreement with related works. We also study ground-state energies of repulsive Bose polarons by examining mixtures in the limit of infinite population imbalance. Finally, we discuss future applications of the FRG to novel problems in Bose-Bose mixtures and related systems.