J. Ruostekoski et Jr. Anglin, Creating vortex rings and three-dimensional skyrmions in Bose-Einstein condensates, PHYS REV L, 86(18), 2001, pp. 3934-3937
We propose a method of generating a vortex ring in a Bose-Einstein condensa
te by means of electromagnetically induced atomic transitions. Some remnant
population of atoms in a second internal state remains within the toroidal
trap formed by the mean-field repulsion of the vortex ring. This populatio
n can he removed. or it can be made to flow around the torus (i.e.. within
the vortex ring). If this flow has a unit topological winding number, the e
ntire structure formed by the two condensates is an example of a three-dime
nsional Skyrmion texture.