Quantum phase transition in Bose-Fermi mixtures

TL;DR

This paper investigates the quantum phase diagram of Bose-Fermi mixtures near a Feshbach resonance, revealing the necessity of repulsive interactions for stability and identifying both first and second order quantum phase transitions.

Contribution

It introduces a quantum field theoretical model with a two-step Gaussian approximation to analyze the phase diagram and transition types in Bose-Fermi mixtures.

Findings

Repulsive boson-boson interactions are essential for stability.

Both first and second order quantum phase transitions are identified.

Characteristics like hysteresis and droplet formation are discussed.

Abstract

We study a quantum Bose-Fermi mixture near a broad Feshbach resonance at zero temperature. Within a quantum field theoretical model a two-step Gaussian approximation allows to capture the main features of the quantum phase diagram. We show that a repulsive boson-boson interaction is necessary for thermodynamic stability. The quantum phase diagram is mapped in chemical potential and density space, and both first and second order quantum phase transitions are found. We discuss typical characteristics of the first order transition, such as hysteresis or a droplet formation of the condensate which may be searched for experimentally.