Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The structure of radiatively induced Lorentz and CPT violation in QED at
  finite temperature   We obtain the induced Lorentz- and CPT-violating term in QED at finite
temperature using imaginary-time formalism and dimensional regularization. Its
form resembles a Chern-Simons-like structure, but, unexpectedly, it does not
depend on the temporal component of the fixed $b_\mu$ constant vector that is
coupled to the axial current. Nevertheless Ward identities are respected and
its coefficient vanishes at T=0, consistently with previous computations with
the same regularization procedure, and it is a non-trivial function of
temperature. We argue that at finite $T$ a Chern-Simons-like Lorentz- and
CPT-violating term is generically present, the value of its coefficient being
unambiguously determined up to a $T-$independent constant, related to the
zero-temperature renormalization conditions.

30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat