Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First and second order transition in frustrated XY systems   The nature of the phase transition for the XY stacked triangular
antiferromagnet (STA) is a controversial subject at present. The field
theoretical renormalization group (RG) in three dimensions predicts a first
order transition. This prediction disagrees with Monte Carlo (MC) simulations
which favor a new universality class or a tricritical transition. We simulate
by the Monte Carlo method two models derived from the STA by imposing the
constraint of local rigidity which should have the same critical behavior as
the original model. A strong first order transition is found. Following Zumbach
we analyze the second order transition observed in MC studies as due to a fixed
point in the complex plane. We review the experimental results in order to
clarify the different critical behavior observed.

18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th