Pairing and condensation in a resonant Bose-Fermi mixture

TL;DR

This paper investigates how strong boson-fermion interactions in a resonant mixture suppress Bose-Einstein condensation, revealing a quantum critical point that connects different physical systems.

Contribution

It introduces a diagrammatic approach to analyze pairing and condensation in Bose-Fermi mixtures near a Fano-Feshbach resonance, identifying a critical coupling where condensation vanishes.

Findings

Boson condensation temperature decreases with increasing coupling.

A quantum critical point exists where condensation disappears.

The critical point aligns with the polaron-molecule transition in imbalanced Fermi gases.

Abstract

We study by diagrammatic methods a mixture of single-component bosons and fermions, with boson-fermion coupling tuned by a Fano-Feshbach resonance. For increasing coupling, the growing boson-fermion pairing correlations progressively reduce the boson condensation temperature and make it eventually vanish at a critical coupling. Such quantum critical point depends very weakly on the population imbalance and for vanishing boson densities coincides with that found for the polaron-molecule transition in a strongly imbalanced Fermi gas, thus bridging two quite distinct physical systems.