Transition from supersonic to subsonic waves in superfluid Fermi gases

TL;DR

This paper investigates how dispersive waves propagate in superfluid Fermi gases across the BEC-BCS crossover, revealing unique subsonic dispersion properties that can differentiate between subsonic and supersonic regimes.

Contribution

It introduces the concept of subsonic dispersion relations in superfluid Fermi gases and demonstrates their potential to distinguish different superfluid regimes at unitarity.

Findings

Dispersive waves in Fermi gases can have subsonic dispersion relations.

Subsonic dispersion patterns appear at the tail of the wave front.

These properties can be used to identify superfluid regimes.

Abstract

We study the propagation of dispersive waves in superfluid Fermi gases in the BEC-BCS crossover. Unlike in other superfluid systems, where dispersive waves have already been studied and observed, Fermi gases can exhibit a subsonic dispersion relation for which the dispersive wave pattern appears at the tail of the wave front. We show that this property can be used to distinguish between a subsonic and a supersonic dispersion relation at unitarity.