https://doi.org/10.1140/epjd/e2012-30091-7
Regular Article
Superfluid Fermi gases in an optical lattice with random defects
Key Laboratory of Atomic Molecular Physics and Functional
Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest
Normal University, Lanzhou
730070, P.R.
China
a
e-mail: xuejk@nwnu.edu.cn
Received: 4 February 2012
Received in final form: 10 May 2012
Published online: 20 July 2012
We investigate the superfluidity of Fermi gases in a deep annular optical lattice with random defects, focusing on discussion of the interplay between defects and Fermi atomic interaction along the BCS-BEC crossover. Within a hydrodynamic scheme and a two-mode approximation, we obtain an analytic expression of atomic density as a function of the defects and the Fermi atomic interaction along the BCS-BEC crossover for supporting a superfluid flow. The analytical results are confirmed by direct numerical simulations. We find that there exists a critical atomic density along the BCS-BEC crossover which divided the system into two regimes: a normal regime with disorder induced damping and a superfluid regime with a plane wave travels coherently through the randomly distributed defects. Importantly, the defects and the atomic interaction are coupled, and the superfluidity of the system strongly depends on the properties of the defects and the atomic interaction. The system easily supports the superfluid states on the BCS side than that on the BEC side.
Key words: Cold Matter and Quantum Gas
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2012