T Koponen et al 2006 New J. Phys. 8 179 doi:10.1088/1367-2630/8/9/179
T Koponen1, J Kinnunen1, J-P Martikainen2, L M Jensen1 and P Törmä1
Show affiliationsPart of Focus on Cold Atoms in Optical Lattices
We consider pairing in a two-component atomic Fermi gas, in a three-dimensional optical lattice, when the components have unequal densities, i.e. the gas is polarized. We show that a superfluid where the translational symmetry is broken by a finite Cooper pair momentum, namely a Fulde–Ferrel–Larkin–Ovchinnikov (FFLO)-type state, minimizes the Helmholtz free energy of the system. We demonstrate that such a state is clearly visible in the observable momentum distribution of the atoms, and analyse the dependence of the order parameter and the momentum distribution on the filling fraction and the interaction strength.
05.30.Fk Fermion systems and electron gas
05.50.+q Lattice theory and statistics (Ising, Potts, etc.)
Issue 9 (September 2006)
Received 7 May 2006
Published 5 September 2006
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