Thermodynamics of Interacting Fermions in Atomic Traps

TL;DR

This paper calculates the entropy of a trapped, resonantly interacting Fermi gas across various magnetic fields, aiding in thermometry and understanding excitations, and calibrates temperature in key experiments with $^6$Li and $^{40}$K.

Contribution

It provides a comprehensive entropy calculation across the BCS-BEC crossover, enabling improved temperature calibration and characterization of excitations in ultracold Fermi gases.

Findings

Entropy varies with temperature and magnetic field in the Fermi gas.

Results improve temperature calibration in experiments with $^6$Li and $^{40}$K.

Characterizes the evolution of excitations across the BCS-BEC crossover.

Abstract

We calculate the entropy in a trapped, resonantly interacting Fermi gas as a function of temperature for a wide range of magnetic fields between the BCS and Bose-Einstein condensation endpoints. This provides a basis for the important technique of adiabatic sweep thermometry, and serves to characterize quantitatively the evolution and nature of the excitations of the gas. The results are then used to calibrate the temperature in several ground breaking experiments on $^6$Li and $^{40}$K.