Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lorentz-breaking effects in scalar-tensor theories of gravity   In this work, we study the effects of breaking Lorentz symmetry in
scalar-tensor theories of gravity taking torsion into account. We show that a
space-time with torsion interacting with a Maxwell field by means of a
Chern-Simons-like term is able to explain the optical activity in syncrotron
radiation emitted by cosmological distant radio sources. Without specifying the
source of the dilaton-gravity, we study the dilaton-solution. We analyse the
physical implications of this result in the Jordan-Fierz frame. We also analyse
the effects of the Lorentz breaking in the cosmic string formation process. We
obtain the solution corresponding to a cosmic string in the presence of torsion
by keeping track of the effects of the Chern-Simons coupling and calculate the
charge induced on this cosmic string in this framework. We also show that the
resulting charged cosmic string gives us important effects concerning the
background radiation.The optical activity in this case is also worked out and
discussed.

35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat