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Title

BCS-BEC crossover in an asymmetric two-component Fermi gas

Author(s)

Liu, Xia-Ji;  Hu, Hui

Abstract

We discuss the superfluid phase transition of a strongly interacting Fermi gas with unequal (asymmetric) chemical potentials in two pairing hyperfine states, and map out its phase diagram near the BCS-BEC crossover. Our approach includes the fluctuation contributions of "preformed Cooper pairs" to the thermodynamic potential at finite temperature. We show that, below a critical difference in chemical potentials between species, a normal gas is unstable towards the formation of either a finite-momentum paired Fulde-Ferrell-Larkin-Ovchinnikov superconducting phase or a uniform superfluid, depending on the asymmetry and interaction strengths. We determine the value of critical chemical potential mismatch, and find that it is consistent with a recent measurement by Zwierlein et al. (Science, 311 (2006) 492).

Publication type

Journal article

Source

Europhysics Letters, Vol. 75, no. 3 (Aug 2006), pp. 364-370

Publication year

2006

FOR Code(s)

01 Mathematical Sciences;  02 Physical Sciences

Keyword(s)

Bardeen-Cooper-Schrieffer superfluid;  BEC-BCS crossovers;  Bose-Einstein condensation;  Degenerate Fermi gases;  Fermion systems;  Nonlinear systems;  Quantum gases;  Statistical physics

Publisher

EDP Sciences

ISSN

0295-5075

Publisher URL

http://dx.doi.org/10.1209/epl/i2006-10136-3

Copyright

Copyright © EDP Sciences (2006). Published version of the paper reproduced here in accordance with the copyright policy of the publisher.

Full text

Peer reviewed