Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Is There a Phase Transition in the Isotropic Heisenberg Antiferromagnet
  on the Triangular Lattice?   The phase diagram of the classical anisotropic (XXZ) Heisenberg model on the
2-dimensional triangular lattice is investigated using Monte Carlo methods. In
the easy-axis limit, two finite temperature vortex unbinding transitions have
been observed. In the easy-plane limit, there also appear to be two distinct
finite temperature phase transitions. The upper transition corresponds to an
Ising-like chirality ordering and the lower temperature transition corresponds
to a Kosterlitz-Thouless vortex unbinding transition. These phase transition
lines all meet at the Heisenberg point and provide strong evidence that the
isotropic model undergoes a novel finite temperature phase transition.

30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin