Constraining Lorentz Violation with Fermi

Understand

One of the cornerstones of special relativity is the postulate that all observers measure exactly the same photon speeds independently on the photon energies.

• However, a hypothesized structure of spacetime may alter this conclusion at ultra-small length scales.
• Even a tiny energy-dependent variation in the speed of light may be revealed, when accumulated over cosmological light-travel times, by high temporal-resolution measurements of sharp features in Gamma-Ray Burst lightcurves.
• We report the results of a study of the emission from GRB 090510 as detected by Fermi's LAT and GBM instruments that set unprecedented limits on the dependence of the speed of light on its energy.