Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electromagnetic radiation produced by avalanches in the magnetization
  reversal of Mn12-Acetate   Electromagnetic radiation produced by avalanches in the magnetization
reversal of Mn12-Acetate has been measured. Short bursts of radiation have been
detected, with intensity significantly exceeding the intensity of the
black-body radiation from the sample. The model based upon superradiance from
inversely populated spin levels has been suggested.

29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph