Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unconventional spin fluctuations in the hexagonal antiferromagnet
  YMnO$_3$   We used inelastic neutron scattering to show that well below its N\'{e}el
temperature, $T_{\rm N}$, the two-dimensional (2D) XY nearly-triangular
antiferromagnet YMnO$_{3}$ has a prominent {\it central peak} associated with
2D antiferromagnetic fluctuations with a characteristic life time of 0.55(5)
ps, coexisting with the conventional long-lived spin-waves. Existence of the
two time scales suggests competition between the N\'{e}el phase favored by weak
interplane interactions, and the Kosterlitz-Thouless phase intrinsic to the 2D
XY spin system.

33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph