Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Creating vortex rings and three-dimensional skyrmions in Bose-Einstein
  condensates   We propose a method of generating a vortex ring in a Bose-Einstein condensate
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 population can be
removed, or it can be made to flow around the torus (i.e. within the vortex
ring). If this flow has unit topological winding number, the entire structure
formed by the two condensates is an example of a three-dimensional skyrmion
texture.

23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph