Shock waves in colliding Fermi gases at finite temperature

TL;DR

This paper investigates shock wave formation in colliding ultracold Fermi gases at finite temperature, comparing Boltzmann and hydrodynamic models to understand the dynamics and the importance of viscosity and thermal conductivity.

Contribution

It introduces a detailed comparison between Boltzmann and hydrodynamic approaches for modeling shock waves in strongly interacting Fermi gases at finite temperature.

Findings

Boltzmann equation accurately describes shock dynamics in the normal phase.

Including shear viscosity and thermal conductivity prevents unphysical behavior.

Hydrodynamic approach requires these terms for realistic modeling.

Abstract

We study the formation and the dynamics of a shock wave originating from the collision between two ultracold clouds of strongly interacting fermions as observed at a lower temperature in an experiment by Joseph et al. [Phys. Rev. Lett. 106, 150401 (2011)]. We use the Boltzmann equation within the test-particle method to describe the evolution of the system in the normal phase. We also show a direct comparison with the hydrodynamic approach and insist on the necessity of including a shear viscosity and a thermal conductivity term in the equations to prevent unphysical behavior from taking place.