BCS-BEC crossover in an asymmetric two-component Fermi gas
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 good qualitative agreement with a recent measurement by Zwierlein \textit{et al.} {[}Science \textbf{311}, 492 (2006){]}.
Cite
@article{arxiv.cond-mat/0603011,
title = {BCS-BEC crossover in an asymmetric two-component Fermi gas},
author = {Xia-Ji Liu and Hui Hu},
journal= {arXiv preprint arXiv:cond-mat/0603011},
year = {2007}
}
Comments
7 pages + 3 figures; To appear in Europhysics Letters