Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heisenberg model on a space with negative curvature: topological spin
  textures on the pseudosphere   Heisenberg-like spins lying on the pseudosphere (a 2-dimensional infinite
space with constant negative curvature) cannot give rise to stable soliton
solutions. Only fractional solutions can be stabilized on this surface provided
that at least a hole is incorporated. We also address the issue of `in-plane'
vortices, in the XY regime. Interestingly, the energy of a single vortex no
longer blows up as the excitation spreads to infinity. This yields a
non-confining potential between a vortex and a antivortex at large distances so
that the pair may dissociate at arbitrarily low temperature.

27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph