Lorentz-breaking effects in scalar-tensor theories of gravity

TL;DR

This paper investigates Lorentz symmetry breaking in scalar-tensor gravity theories with torsion, exploring effects on optical activity, cosmic string formation, and background radiation, revealing new interactions and physical implications.

Contribution

It introduces a model with torsion and Chern-Simons coupling in scalar-tensor gravity, analyzing optical activity, cosmic string solutions, and induced charges, advancing understanding of Lorentz-breaking effects.

Findings

Torsion coupled with Maxwell field explains optical activity in distant radio sources.

Charged cosmic strings are formed with significant effects on background radiation.

Lorentz breaking influences cosmic string properties and related cosmological phenomena.

Abstract

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.