Universal behavior of perturbation-induced defects in trapped superfluids
We address universal features in the defect dynamics formed after sudden perturbations in ultra-cold gas superfluids which are confined in elongated traps. Our studies, based on simulations of the complex time-dependent Ginzburg-Landau equation focus on both phase imprinting (at angles away from π), and localized density depletion perturbations. The challenge we address has to do with the equilibration process: how a superfluid system eventually eliminates an extended planar defect which these experiments induce. In contrast to earlier work where soliton-vortex ring oscillations were reported, we observe planar phase gradients coexisting with one or more near-trap-edge vortex rings. The latter repeatedly enter and exit the trap as the phase gradient dissipates.
2D density depletion simulation.
2D phase imprinting simulation, 130°.
3D density depletion simulation.
3D phase imprinting simulation, 130°.
2D density depletion simulation, inhomogeneous cylindrical geometry.