Stability of superflow for ultracold fermions in optical lattices.
We investigate the stability of superflow of paired fermions in an optical lattice. We show that there are two distinct dynamical instabilities which limit the superflow in this system. One dynamical instability occurs when the superfluid stiffness becomes negative; this evolves, with increasing pairing interaction, from the fermion pair breaking instability to the well-known dynamical instability of lattice bosons. The second, more interesting, dynamical instability is marked by the emergence of a transient atom density wave. Both dynamical instabilities can be experimentally accessed by tuning the pairing interaction and the fermion density.
Burkov
A A
AA
Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Paramekanti
Arun
A