Larkin-Ovchinnikov phases in two-dimensional square lattices

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Abstract

We consider a two-component gas of fermions in optical lattices in the presence of a population imbalance within a mean-field theory. We study phase transitions from a normal gas of unpaired fermions to a superfluid phase of Bose-condensed Cooper pairs. The possibility of Cooper pairs with a nonzero centre-of-mass momentum is included, which corresponds to a so-called Fulde–Ferrel–Larkin–Ovchinnikov (FFLO) state. We find that for population-imbalanced systems such states can form the ground state. The FF and LO state are compared and it is shown that actually the LO state is energetically more favourable. We complete the mean-field phase diagram for the LO phase and show that it is qualitatively in excellent agreement with recent diagrammatic Monte Carlo calculations. Subsequently, we calculate the atomic density modulations in the LO phase.

Details

Original languageEnglish
Pages (from-to)1795-1804
Number of pages10
JournalJournal of Modern Optics
Volume63
Issue number18
Publication statusPublished - Jan 2016
MoE publication typeA1 Journal article-refereed

    Research areas

  • exotic superfluids, FFLO, imbalanced Fermi gases, optical lattices

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