Dynamics of trapped two-component Fermi gas: temperature dependence of the transition from collisionless to collisional regime

TL;DR

This paper presents a numerical study of a two-component Fermi gas in a trap, analyzing how temperature influences the transition from collisionless to collisional behavior, with findings aligning qualitatively with experimental results.

Contribution

It introduces a numerical method to explore the temperature-dependent dynamics of trapped Fermi gases and uncovers a new effect of temperature on the transition to hydrodynamic behavior.

Findings

Good qualitative agreement with experiments

Temperature affects collision rate and efficiency

Transition shifts to lower collision rates at lower temperatures

Abstract

We develop a numerical method to study the dynamics of a two-component atomic Fermi gas trapped inside a harmonic potential at temperature T well below the Fermi temperature Tf. We examine the transition from the collisionless to the collisional regime down to T=0.2 Tf and find good qualitative agreement with the experiments of B. DeMarco and D.S. Jin [Phys. Rev. Lett. vol. 88, 040405 (2002)]. We demonstrate a twofold role of temperature on the collision rate and on the efficiency of collisions. In particular we observe an hitherto unreported effect, namely that the transition to hydrodynamic behavior is shifted towards lower collision rates as temperature decreases.