Dynamical properties of a trapped dipolar Fermi gas at finite temperature

TL;DR

This paper explores the finite-temperature dynamics of a trapped dipolar Fermi gas, revealing anisotropic expansion, isotropic collapse, and temperature-dependent collective excitations, advancing understanding of dipolar quantum gases.

Contribution

It provides the first detailed analysis of the dynamical behavior of finite-temperature dipolar Fermi gases, including expansion, collapse, and collective modes, highlighting differences from Bose-Einstein condensates.

Findings

Expanded gas stretches along dipole direction.

Collapse is isotropic, contrasting with dipolar BECs.

Collective excitation frequencies depend on interaction and temperature.

Abstract

We investigate the dynamical properties of a trapped finite-temperature normal Fermi gas with dipole-dipole interaction. For the free expansion dynamics, we show that the expanded gas always becomes stretched along the direction of the dipole moment. In addition, we present the temperature and interaction dependences of the asymptotical aspect ratio. We further study the collapse dynamics of the system by suddenly increasing the dipolar interaction strength. We show that, in contrast to the anisotropic collapse of a dipolar Bose-Einstein condensate, a dipolar Fermi gas always collapses isotropically when the system becomes globally unstable. We also explore the interaction and temperature dependences for the frequencies of the low-lying collective excitations.