Lorentz Symmetry breaking studies with photons from astrophysical observations

TL;DR

This paper reviews recent astrophysical observations of photons to test Lorentz Invariance Violation, setting limits on Quantum Gravity effects through time-of-flight measurements from gamma-ray sources.

Contribution

It provides a comprehensive review of recent time delay studies using gamma-ray observations to constrain Lorentz symmetry breaking effects.

Findings

No significant time-lag detected within experimental precision.

Established 95% confidence limits on Quantum Gravity scale for linear and quadratic dispersion relations.

Compared performance of various time delay search methods.

Abstract

Lorentz Invariance Violation (LIV) may be a good observational window on Quantum Gravity physics. Within last few years, all major Gamma-ray experiments have published results from the search for LIV with variable astrophysical sources: gamma-ray bursts with detectors on-board satellites and Active Galactic Nuclei with ground-based experiments. In this paper, the recent time-of-flight studies with unpolarized photons published from the space and ground based observations are reviewed. Various methods used in the time delay searches are described, and their performance discussed. Since no significant time-lag value was found within experimental precision of the measurements, the present results consist of 95% confidence cevel limits on the Quantum Gravity scale on the linear and quadratic terms in the standard photon dispersion relations.