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arXiv · 0809.0350

Stability of superfluid Fermi gases in optical lattices

Yoshihiro Yunomae·Ippei Danshita·Daisuke Yamamoto·Nobuhiko Yokoshi·Shunji Tsuchiya
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Abstract

Critical velocities of superfluid Fermi gases in optical lattices are theoretically investigated across the BCS-BEC crossover. We calculate the excitation spectra in the presence of a superfluid flow in one- and two-dimensional optical lattices. It is found that the spectrum of low-lying Anderson-Bogoliubov (AB) mode exhibits a roton-like structure in the short-wavelength region due to the strong charge density wave fluctuations, and with increasing the superfluid velocity one of the roton-like minima reaches zero before the single-particle spectrum does. This means that superfluid Fermi gases in optical lattices are destabilized due to spontaneous emission of the roton-like AB mode instead of due to Cooper pair breaking.

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Yoshihiro Yunomae, Ippei Danshita, Daisuke Yamamoto, Nobuhiko Yokoshi, Shunji Tsuchiya. 2009-04-21. Stability of superfluid Fermi gases in optical lattices. https://doi.org/10.1088/1742-6596/150/3/032128

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