Astrophysical limits on quantum gravity motivated birefringence

TL;DR

This paper establishes observational upper limits on quantum gravity-induced birefringence effects by analyzing polarization data from distant astrophysical sources, constraining theoretical models.

Contribution

It provides the first empirical bounds on quantum gravity related birefringence using optical and ultraviolet polarization measurements.

Findings

Upper bound on birefringence parameter: χ < 10^{-3}

Analysis of polarization in optical/UV spectra of distant sources

Constraints on quantum gravity models based on observational data

Abstract

We obtain observational upper bounds on a class of quantum gravity related birefringence effects, by analyzing the presence of linear polarization in the optical and ultraviolet spectrum of some distant sources. In the notation of Gambini and Pullin we find $\chi < 10^{-3}$.