Rotating bubble shaped Bose-Einstein condensates

Speaker: Dr Angela White
Affiliation: University of Queensland

Abstract

The demonstration of Bose-Einstein condensates confined to a thin hollow shell in the microgravity environment of the Cold Atomic Laboratory on the International Space Station has opened up the exploration of this intriguing simply connected topology. The closed curved surface of a bubble condensate imposes additional restrictions on superfluid dynamics arising from the continuous nature of the condensate phase. Under an external rotation, the minimum energy configuration consists of vortex pairs, with the second vortex rotating with opposite circulation and aligned at the antipode of the condensate shell. We investigate the response of three-dimensional spherical-shell condensates to rotation and show that at low rotation rates, two aligned triangular Abrikosov-like vortex lattices are formed on each hemispherical surface. As the rotation rate is increased, we see a transition to a multi-charge vortex anti-vortex pair at each pole, surrounded by singly charged vortices in the bulk density. At larger rotation rates, a deformation in the spherical shell shape due to the centrifugal barrier is also observed.