Oblique collisions and catching-up phenomena of vortex dipoles in a uniform Bose–Einstein condensate

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.

Sound emission and annihilations in a programmable quantum vortex collider

“…In 120 • collisions, we mostly observe partial annihilation of the shorter outgoing dipole (Extended Data Fig. 4), occurring at d a about ∼ 30% larger than the head-on case, because of the final asymmetric configuration 54 . The extracted Γ and d a suggest that annihilation occurs whenever the energy dissipated during the collision is sufficiently large to reduce the initial dipole size to about d c 17 .…”

Dissipative dynamics of quantum vortices in fermionic superfluid

“…While the original prediction was derived based on quasi-classical arguments (vortex is approximated as a container that holds gas of quasiparticles), here we provide a fully microscopic description of this process. We emphasize that its description is beyond the capability of the Gross-Pitaevskii approach, which is the only one that was used to study vortex collisions so far [1,[43][44][45].…”