Faraday rotation and primordial magnetic field constraints on Ultraviolet Lorentz violation with spacetime torsion

TL;DR

This paper investigates how Faraday rotation and cosmic microwave background data can constrain spacetime torsion related to ultraviolet Lorentz violation, providing bounds that are comparable or more stringent than previous limits.

Contribution

It demonstrates a method to constrain spacetime torsion using electromagnetic observations, extending prior work on Lorentz violation and torsion effects in spacetime.

Findings

Torsion constrained to approximately 10^{-18} GeV from CMB data.

Galactic dynamo seed magnetic fields imply a torsion limit of about 10^{-33} GeV.

Constraints are less stringent than some previous bounds but can be improved with gamma-ray burst data.

Abstract

Recently Kahniashivili et al (2006) presented a unified treatment for ultraviolet Lorentz violation (LV) testing through electromagnetic wave propagation in magnetised plasmas, based on dispersion and rotation measured data. Based on the fact discovered recently by Kostelecky et al (2008), that LV may place constraints on spacetime torsion, in this paper it is shown that on the limit of very low frequency torsion waves, it is possible to constraint torsion from Faraday rotation and CMB on a similar fashion as Minkowski spacetime plus torsion. Here the Maxwells modified equations are obtained by a perturbative method introduced by de Sabbata and Gasperini (1981). Torsion is constraint to $Q_{CMB}\approx{10^{-18}GeV}$ which is not so stringent as the $10^{-31}GeV$ obtained by Kostelecky et al. However, Gamma Ray Bursts (GBRs) may lead to the more string value obtined by Kostelecky et al. Another interesting constraint on torsion is shown to be placed by galactic dynamo seed magnetic fields. For torsion effects be compatible with the galactic dynamo seeds one obtains a torsion constraint of $10^{-33}GeV$ which is two orders of magnitude more stringent that the above Kostelecky et al limit.