Stripes and honeycomb lattice of quantized vortices in rotating two-component Bose-Einstein condensates

TL;DR

This paper numerically investigates vortex lattice structures in two-component Bose-Einstein condensates, revealing diverse configurations like stripes and honeycomb lattices due to SU(2) symmetry, and identifies complex structures as hexagonal half-skyrmion lattices.

Contribution

It demonstrates the formation of various vortex lattice configurations in two-component BECs and links these to SU(2) symmetry and half-skyrmion structures, providing new insights into their degeneracy and lattice transformations.

Findings

Vortex lattices include stripes, honeycomb, and complex structures.

Degeneracy from SU(2) symmetry allows continuous transformation between lattice types.

Complex lattices are identified as hexagonal half-skyrmion arrangements.

Abstract

We study numerically the structure of a vortex lattice in two-component Bose-Einstein condensates with equal atomic masses and equal intra- and inter-component coupling strengths. The numerical simulations of the Gross-Pitaevskii equation show that the quantized vortices form uncertain lattice configurations accompanying the vortex stripes, honeycomb lattices, and their complexes. This is a result of the degeneracy of the system for the SU(2) symmetric operation, which makes a continuous transformation between the above structures. In terms of the pseudospin representation, the complex lattice structures are identified to a hexagonal lattice of doubly-winding half-skyrmions.