Annihilation and recurrence of vortex-antivortex pairs in two-component Bose-Einstein condensates

TL;DR

This paper demonstrates that in two-component Bose-Einstein condensates, vortex-antivortex pairs can annihilate without dissipation or catalysts when intercomponent interactions are strong, and such pairs can recur alternately in the two components.

Contribution

It reveals a new mechanism for vortex-antivortex annihilation and recurrence in two-component BECs independent of dissipation or catalysts.

Findings

Vortex-antivortex pairs can annihilate without dissipation in two-component BECs.

Pairs can be recreated alternately in the two components under certain conditions.

Recurrence of vortex-antivortex pairs is observed in the simulations.

Abstract

The annihilation of vortex-antivortex pairs is a key event in two-dimensional Bose-Einstein condensates (BECs). It is known that dissipation or a catalyst vortex is required for the annihilation of the pairs in one-component BECs. We numerically confirmed in two-component BECs that the pairs can be annihilated even without any dissipation or catalyst vortices when the intercomponent interaction is strong. In addition, the pair is recreated alternately in two components under certain conditions, which we call the recurrence.