Spin 1/2 fermions in the unitary regime: a superfluid of a new type.

Phys Rev Lett

Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA.

Published: March 2006

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.

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http://dx.doi.org/10.1103/PhysRevLett.96.090404DOI Listing

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