Fulde-Ferrell-Larkin-Ovchinnikov superfluidity in one-dimensional optical lattices

Abstract

Spin-polarized attractive Fermi gases in one-dimensional (1D) optical lattices are expected to be remarkably good candidates for the observation of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase. We model these systems with an attractive Hubbard model with population imbalance. By means of the density-matrix renormalization-group method we compute the pairing correlations as well as the static spin and charge structure factors in the whole range from weak to strong coupling. We demonstrate that pairing correlations exhibit quasi-long range order and oscillations at the wave number expected from FFLO theory. However, we also show by numerically computing the mixed spin-charge static structure factor that charge and spin degrees of freedom appear to be coupled already for small imbalance. We discuss the consequences of this coupling for the observation of the FFLO phase, as well as for the stabilization of the quasi-long range order into long-range order by coupling many identical 1D systems, as in quasi-1D optical lattices.

7 pages, 5 figures, submitted

References in corpus (7)

• Pairing states of a polarized Fermi gas trapped in a one-dimensional optical lattice
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• Phase Transitions and Pairing Signature in Strongly Attractive Fermi Atomic Gases
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Cited by in corpus (4)

• The FFLO state in the one-dimensional attractive Hubbard model and its fingerprint in the spatial noise correlations
• Spectral signatures of the Fulde-Ferrell-Larkin-Ovchinnikov order parameter in one-dimensional optical lattices
• Magnetic ordering and quantum statistical effects in strongly repulsive Fermi-Fermi and Bose-Fermi mixtures
• Collective excitations in one-dimensional ultracold Fermi gases: a comparative study