Europhys. Lett.
Volume 74, Number 4, May 2006
Page(s) 574 - 580
Section General
Published online 12 April 2006
Europhys. Lett., 74 (4), pp. 574-580 (2006)
DOI: 10.1209/epl/i2006-10023-y

Equation of state of a superfluid Fermi gas in the BCS-BEC crossover

H. Hu, X.-J. Liu and P. D. Drummond

ARC Centre of Excellence for Quantum-Atom Optics, Department of Physics University of Queensland - Brisbane, QLD 4072, Australia

received 30 January 2006; accepted in final form 22 March 2006
published online 12 April 2006

We present a theory for a superfluid Fermi gas near the BCS-BEC crossover, including pairing fluctuation contributions to the free energy similar to that considered by Nozières and Schmitt-Rink for the normal phase. In the strong coupling limit, our theory is able to recover the Bogoliubov theory of a weakly interacting Bose gas with a molecular scattering length very close to the known exact result. We compare our results with recent Quantum Monte Carlo simulations both for the ground state and at finite temperature. Excellent agreement is found for all interaction strengths where simulation results are available.

03.75.Hh - Static properties of condensates; thermodynamical, statistical, and structural properties.
03.75.Ss - Degenerate Fermi gases.
05.30.Fk - Fermion systems and electron gas.

© EDP Sciences 2006