Santiago F. Caballero-Benitez, Rosario Paredes, Victor Romero-Rochin
Using mean-field theory for the Bardeen-Cooper-Schriefer (BCS) to the
Bose-Einstein condensate (BEC) crossover we investigate the ground state
thermodynamic properties of an interacting homo- geneous Fermi gas. The
interatomic interactions modeled through a finite range potential allows us to
explore the entire region from weak to strong interacting regimes with no
approximations. To exhibit the thermodynamic behavior as a function of the
potential parameters in the whole crossover region, we concentrate in studying
the contact variable, the thermodynamic conjugate of the inverse of the s-wave
scattering length. Our analysis allows us to validate the correctness of the
contact approximation in the strong interacting regime where the scattering
length diverges in the limit of zero potential range. It also leads to predict
a quantum phase transition-like in the opposite case when the potential range
becomes large. These findings are direct consequence of the k-dependent energy
gap for finite interaction range potentials.
View original:
http://arxiv.org/abs/1202.2939
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