Collective modes as a probe of imbalanced Fermi gases

Abstract

We theoretically investigate the collective modes of imbalanced two component one-dimensional Fermi gases with attractive interactions. This is done for trapped and untrapped systems both at zero and non-zero temperature, using self-consistent mean-field theory and the random phase approximation. We discuss how the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state can be detected and the periodicity of the associated density modulations determined from its collective mode spectrum. We also investigate the accuracy of the single mode approximation for low-lying collective excitations in a trap by comparing frequencies obtained via sum rules with frequencies obtained from direct collective mode calculations. It is found that, for collective excitations where the atomic clouds of the two spin species oscillate largely in phase, the single mode approximation holds well for a large parameter regime. Finally we investigate the collective mode spectrum obtained by parametric modulation of the coupling constant.

11 pages, 9 figures

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Cited by in corpus (11)

• Fermi gases in one dimension: From Bethe Ansatz to experiments
• The Fulde-Ferrell-Larkin-Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review
• Fluctuations and phase transitions in Larkin-Ovchinnikov liquid crystal states of population-imbalanced resonant Fermi gas
• Expansion dynamics of the Fulde-Ferrell-Larkin-Ovchinnikov state
• Collective modes of a soliton train in a Fermi superfluid
• Superfluidity of a spin-imbalanced Fermi gas in a three-dimensional optical lattice
• Protocol to engineer Fulde-Ferrell-Larkin-Ovchinnikov states in a cold Fermi gas
• Triplet pair correlations in {\it s-}wave superfluids as a signature of the FFLO state
• Collective modes in Fulde-Ferrell-Larkin-Ovchinnikov superconductors: The role of long-range Coulomb interaction and signatures in density response
• Detecting Topological Phase Transition in Superconductor-Semiconductor Hybrids by Electronic Raman Spectroscopy
• Novel dynamical excitations and roton-based measurement of Cooper-pair momentum in a two-dimensional Fulde-Ferrell-Larkin-Ovchinnikov superfluid on optical lattices