Vortex nucleation in rotating BEC: the role of the boundary condition for the order parameter

TL;DR

This paper investigates how boundary conditions influence vortex nucleation in rotating 2D Bose-Einstein condensates, revealing vortex-antivortex pair creation far from the center and the importance of surface modes.

Contribution

It demonstrates the impact of boundary conditions on vortex nucleation mechanisms in BECs within the Gross-Pitaevskii framework, emphasizing vortex-antivortex pair formation and surface mode roles.

Findings

Vortex-antivortex pairs form far from the condensate center.

Vortices move inward while antivortices move outward.

Surface modes play a significant role in nucleation.

Abstract

We study the process of vortex nucleation in rotating two-dimensional BEC confined in a harmonic trap. We show that, within the Gross-Pitaevskii theory with the boundary condition of vanishing of the order parameter at infinity, topological defects nucleation occurs via the creation of vortex-antivortex pairs far from the cloud center, where the modulus of the order parameter is small. Then, vortices move towards the center of the cloud and antivortices move in the opposite direction but never disappear. We also discuss the role of surface modes in this process.