Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: About the connection between vacuum birefringence and the light-light
  scattering amplitude   Birefringence phenomena stemming from vacuum polarization are revisited in
the framework of coherent scattering. Based on photon-photon scattering, our
analysis brings out the direct connection between this process and vacuum
birefringence. We show how this procedure can be extended to the Kerr and the
Cotton-Mouton birefringences in vacuum, thus providing a unified treatment of
various polarization schemes, including those involving static fields.

28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys