Phase separation in imbalanced fermion superfluids beyond mean-field

TL;DR

This paper develops a path-integral approach to study phase separation in imbalanced ultracold Fermi gases, emphasizing the importance of quantum fluctuations and finite temperature effects on density profiles.

Contribution

It introduces a method beyond mean-field to accurately model density distributions, incorporating fluctuations and temperature effects in imbalanced fermion superfluids.

Findings

Density profiles match experimental data well.

Quantum fluctuations and temperature significantly affect phase separation.

Density profiles can determine superfluid core temperature.

Abstract

The density distributions of the two components of a trapped, ultracold Fermi gas with population imbalance reveal the effect of imbalance on superfluid pairing. We develop a path-integral derivation of the density, that takes into account both fluctuations beyond mean-field and effects of nonzero temperature. The calculated density profiles compare favorably to the measured density profiles, and illustrate the necessity to incorporate both quantum fluctuations and finite temperature effects. The temperature dependence of the density profiles, especially near the superfluid-normal interface, allows determining the temperature of the superfluid core in current experiments.