Second sound in Fermi gases at the BCS-BEC crossover

TL;DR

This paper investigates second sound and thermodynamic properties of Fermi gases across the BCS-BEC crossover, providing insights into superfluid behavior and critical temperature through detailed calculations.

Contribution

It presents a comprehensive calculation of thermodynamic potential, entropy, specific heat, and sound modes including corrections, across the BCS to unitarity regime.

Findings

Second sound speed varies with temperature and interaction strength.

Thermodynamic quantities show distinct behavior across the crossover.

Second sound serves as a clear indicator of superfluidity and critical temperature.

Abstract

The thermodynamic potential is calculated for a uniform superfluid gas of fermi atoms from the mean field BCS equations including corrections from induced interactions, Hartree-Fock energies and quasiparticle selfenergies. The entropy, specific heat and sound modes are calculated as function of temperature, density and interaction strength from the BCS to the unitarity limit and around the BCS-BEC crossover. The second sound speed is of particular interest as it is a clear signal of a superfluid component and it determines the critical temperature.