Pairing and Superfluid Properties of Dilute Fermion Gases at Unitarity

TL;DR

This paper investigates the pairing and superfluid characteristics of a dilute fermion gas at unitarity using non-perturbative Monte Carlo methods, providing insights into critical temperatures and pairing correlations.

Contribution

The study applies the Restricted Path Integral Monte Carlo method to analyze finite-temperature superfluid properties of a unitarity fermion gas, offering new quantitative estimates of critical temperatures.

Findings

Total energy at low temperature matches previous ground-state results.

Pairing correlations develop below T* ≈ 0.70 ε_F.

Superfluid transition occurs around Tc ≈ 0.25 ε_F.

Abstract

We study the system of a dilute gas of fermions in 3-dimensions, with attractive interactions tuned to the unitarity point, using the non-perturbative Restricted Path Integral Monte Carlo (R-PIMC) method. The pairing and superfluid properties of this system are calculated at finite temperature. The total energy at very low temperature from our results agrees closely with that of previous ground-state Quantum Monte Carlo calculations. We identify the temperature $T^\ast\approx 0.70\epsilon_F$ below which pairing correlations develop, and estimate the critical temperature for the superfluid transition $T_c\approx 0.25\epsilon_F$ from a finite size scaling analysis of the superfluid density.