Wednesday, December 12, 2012

1212.2299 (Daisuke Yamamoto et al.)

Flow-Induced Charge Modulations in Superfluid Atomic Fermions Loaded
into an Optical Kagome Lattice

Daisuke Yamamoto, Chika Sato, Tetsuro Nikuni, Shunji Tsuchiya
We study the superfluid state of atomic fermions in a tunable optical kagome lattice motivated by recent experiments. We show that imposed superflow induces spatial modulations in density and superfluid order parameter and leads to a charge modulated superfluid state analogous to a supersolid state. The spatial modulations in the superfluid emerge due to the geometric effect of the kagome lattice that introduces anisotropy in hopping amplitudes of fermion pairs in the presence of superflow. We also study superflow instabilities and find that the critical current limited by the dynamical instability is quite enhanced due to the large density of states associated with the flat band. The charge modulated superfluid state can sustain high temperatures close to the transition temperature that is also enhanced due to the flat band, and is therefore realizable in experiments.
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