Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmological background torsion inhomogeneities and Lorentz violation in
  QED   A non-minimal photon-torsion axial coupling in the quantum electrodynamics
(QED) framework is considered. The geometrical optics in Riemann-Cartan
spacetime is considering and a plane wave expansion of the electromagnetic
vector potential is considered leading to a set of the equations for the ray
congruence. Since we are interested mainly on the torsion effects in this first
report we just consider the Riemann-flat case composed of the Minkowskian
spacetime with torsion. It is also shown that in torsionic de Sitter background
the vacuum polarisation does alter the propagation of individual photons, an
effect which is absent in Riemannian spaces. It is shown that the cosmological
torsion background inhomogeneities induce Lorentz violation and massive photon
modes in this QED.

20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat