Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stimulated Thermalization of a Parametrically Driven Magnon Gas as a
  Prerequisite for Bose-Einstein Magnon Condensation   Thermalization of a parametrically driven magnon gas leading to the formation
of a Bose-Einstein condensate at the bottom of a spin-wave spectrum was studied
by time- and wavevector-resolved Brillouin light scattering spectroscopy. It
has been found that the condensation is preceded by the conversion of initially
pumped magnons into a second group of frequency degenerated magnons, which
appear due to parametrically stimulated scattering of the initial magnons to a
short-wavelength spectral region. In contrast to the first magnon group, which
wavevectors are orthogonal to the wavevectors of the magnons at the lowest
energy states, the secondary magnons can effectively scatter to the bottom of
the spectrum and condense there.

37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas