Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photon-neutrino interactions in magnetic fields   The low-energy two neutrino-two photon interactions in the presence of
homogeneous magnetic field are studied. The cross sections in external magnetic
field are shown to be larger than in vacuum by factor $\sim (m_W /m_e)
^4(B/B_c) ^2$. The energy-loss rate due to the process $\gamma \gamma \to \nu
\bar{\nu}$ in magnetic field is obtained.

5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol