Spin 1/2 fermions in the unitary regime: a superfluid of a new type.
We study, in a fully nonperturbative calculation, a dilute system of spin 1/2 interacting fermions, characterized by an infinite scattering length at finite temperatures. Various thermodynamic properties and the condensate fraction are calculated and we also determine the critical temperature for the superfluid-normal phase transition in this regime. The thermodynamic behavior appears as a rather surprising and unexpected mélange of fermionic and bosonic features. The thermal response of a spin 1/2 fermion at the BCS-BEC crossover should be classified as that of a new type of superfluid.
Bulgac
Aurel
A
Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA.
Drut
Joaquín E
JE
Magierski
Piotr
P