Thermodynamics and coherence of a trapped dipolar Fermi gas

TL;DR

This paper presents a meanfield semiclassical approach to analyze thermodynamics and coherence in a trapped dipolar Fermi gas, revealing how trap geometry and exchange interactions influence system properties.

Contribution

It introduces a self-consistent Hartree-Fock method for dipolar Fermi gases in traps, including a simplified formalism for anisotropic traps, and highlights the limitations of uniform gas predictions.

Findings

System entropy varies with trap geometry, enabling cooling.

Exchange interactions induce anisotropic correlations at low temperatures.

Uniform gas thermodynamics are unreliable for trapped systems, especially in oblate traps.

Abstract

We develop a meanfield treatment of a polarized trapped Fermi gas with dipole-dipole interactions. Our approach is based on self-consistent semiclassical Hartree-Fock theory that accounts for direct and exchange interactions. We discuss our procedure for numerically implementing the calculation. We study the thermodynamic and the first and second order correlation properties of the system. We find that the system entropy depends on the trap geometry, allowing the system to be cooled as the trap aspect ratio is increased, and that exchange interactions cause the correlation functions to be anisotropic in the low temperature regime. We also find that many uniform gas thermodynamic predictions, for which direct interaction effects vanish, are qualitatively unreliable for trapped systems, most notably for oblate traps. We develop a simplified Hartree formalism that is applicable to anisotropic harmonic traps.