Formation and dynamics of vortices in a Bose–Einstein condensate with a moving impenetrable disk-shaped potential

We consider a quasi-two-dimensional Bose-Einstein condensate with a moving impenetrable disk-shaped potential. By performing direct numerical simulations, we investigate the formation and dynamics of the vortices in the wake as a function of the moving velocity and the radius of the potential. For moderate moving velocity, we observe the formation of a bound vortex pair in the wake of the potential. Its shedding period and associated patterns depend on the radius of the potential, showing V-shaped, periodic, or complex wakes. More interestingly, at high velocity both the vortex pair and vortex dipole can be formed simultaneously. Furthermore, the activation time for vortex formation is investigated for different velocities. We also give an experimental protocol to observe these phenomena in future experiments.