Supersonic and subsonic shock waves in the unitary Fermi gas

TL;DR

This paper analyzes shock wave formation in a unitary Fermi gas using superfluid hydrodynamics, providing analytical solutions and simulations that reveal how shocks evolve and disperse into ripples depending on initial conditions.

Contribution

It offers the first analytical solutions for shock dynamics in a unitary Fermi gas and demonstrates the role of dispersive regularization in shock evolution.

Findings

Shock waves form rapidly with divergent density gradients.

Dispersive effects lead to ripple formation after shock.

Initial conditions significantly influence shock ripple properties.

Abstract

We investigate shock waves in the unitary Fermi gas by using the zero-temperature equations of superfluid hydrodynamics. We obtain analytical solutions for the dynamics of a localized perturbation of the uniform gas. These supersonic bright and subsonic dark solutions produce, after a transient time, an extremely large (divergent) density gradient: the shock. We calculate the time of formation of the shock and also simulate the space-time behavior of the waves by solving generalized hydrodynamic equations, which include a reliable dispersive regularization of the shock. We find that the shock spreads into wave ripples whose properties crucially depend on the chosen initial configuration.