  Within the simplest holographic superfluid model and without any ingredients
put by hand, it is shown that vortices can be generated when the angular
velocity of rotating superfluids exceeds certain critical values, which can be
precisely determined by linear perturbation analyses (quasi-normal modes of the
bulk AdS black brane). These vortices appear at the edge of the superfluid
system first, and then automatically move into the bulk of the system, where
they are eventually stabilized into certain vortex lattices. For the case of 18
vortices generated, we find (at least) five different patterns of the final
lattices formed due to different initial perturbations, which can be compared
to the known result for such lattices in weakly coupled Bose-Einstein
condensates from free energy analyses.
