Phase slip in a superfluid Fermi gas near a Feshbach resonance

TL;DR

This paper investigates phase slips in a superfluid Fermi gas near a Feshbach resonance, demonstrating their potential as direct evidence of superfluidity and analyzing their properties across the BCS-BEC crossover.

Contribution

It provides a detailed analysis of phase slip characteristics in superfluid Fermi gases near resonance, highlighting their temperature dependence and experimental signatures.

Findings

Phase slips appear as density dips below the superfluid transition temperature.

The width of phase slips scales with the square root of temperature difference.

Phase slip signatures become more prominent across the BCS-BEC crossover.

Abstract

In this paper, we study the properties of a phase slip in a superfluid Fermi gas near a Feshbach resonance. The phase slip can be generated by the phase imprinting method. Below the superfluid transition temperature, it appears as a dip in the density profile, and becomes more pronounced when the temperature is lowered. Therefore the phase slip can provide a direct evidence of the superfluid state. The condensation energy of the superfluid state can be extracted from the density profile of the phase slip, due to the unitary properties of the Fermi gas near the resonance. The width of the phase slip is proportional to the square root of the difference between the transition temperature and the temperature. The signature of the phase slip in the density profile becomes more robust across the BCS-BEC crossover.