Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Competing nematic interactions in a generalized XY model in two and
  three dimensions   We study a generalization of the XY model with an additional nematic-like
term through extensive numerical simulations and finite-size techniques, both
in two and three dimensions. While the original model favors local alignment,
the extra term induces angles of $2\pi/q$ between neighboring spins. We focus
here on the $q=8$ case (while presenting new results for other values of $q$ as
well) whose phase diagram is much richer than the well known $q=2$ case. In
particular, the model presents not only continuous, standard transitions
between Berezinskii-Kosterlitz-Thouless (BKT) phases as in $q=2$, but also
infinite order transitions involving intermediate, competition driven phases
absent for $q=2$ and 3. Besides presenting multiple transitions, our results
show that having vortices decoupling at a transition is not a suficient
condition for it to be of BKT type.

29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg