Physica Scripta
Oblique collisions and catching-up phenomena of vortex dipoles in a uniform Bose–Einstein condensate
Guoquan Yang, Suying Zhang, Wei Han
Abstract
Abstract We investigate the collisional dynamics of two vortex dipoles in a uniform two-dimensional Bose–Einstein condensate. It is found that the dynamics are deeply related to the moving directions and sizes of the initial vortex dipoles. For the oblique collisions of two vortex dipoles with the same size, we find that the vortices in the two initial vortex dipoles recombine into two new vortex dipoles which scatter in the opposite directions. For the catching-up processes of two vortex dipoles with different size, we find that the faster vortex dipole speeds up and passes through the slower vortex dipole. If the size of the vortex dipoles are small, we also observe vortex annihilation and vortex resurrection. The corresponding parameter ranges of different collisional dynamics are discussed.