2010/10/06 by Zlatko Koinov, Koinov, Zlatko
Physics and Astronomy · #Atomic and Subatomic Physics Research #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Quantum, superfluid, helium dynamics #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.1010.1200
openalex publication_date 2010/10/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We derive the Bethe-Salpeter (BS) equations for the collective-mode spectrum\nof superfluid Fermi gases of equal mixture of atomic Fermi gas of two hyperfine\nstates loaded into a moving optical lattice. In a moving lattice the superfluid\nstate is unstable due to spontaneous emission of the short-wavelength rotonlike\nexcitations which appear in the spectrum of the collective modes. It is shown\nthat the spectrum obtained by the BS equations is in an excellent agreement\nwith the collective-mode dispersion calculated by the perturbation approach,\nwhile there are some differences between the results obtained by density\nresponse function method and by the BS approach. The difference increases with\nincreasing the lattice velocity, which can be seen in the analytical\napproximations for the dispersion relation in the long-wavelength limit in a\nweak-coupling regime.\n