Comments on Challenges for Quantum Gravity

TL;DR

This paper analyzes the impact of Lorentz-violating operators at the Planck scale, deriving stringent observational bounds on their parameters, which significantly constrain theories of quantum gravity.

Contribution

It provides the most stringent observational bounds to date on Lorentz violation parameters associated with quantum gravity effects.

Findings

Bounds on Lorentz-violating parameters are of order 10^{-15}

Observational data strongly constrain Planck-scale physics models

Results improve previous limits on Lorentz violation

Abstract

We examine radiative corrections arising from Lorentz violating dimension five operators presumably associated with Planck scale physics as recently considered by Myers and Pospelov. We find that observational data result in bounds on the dimensionless parameters of the order $10^{-15}$. These represent the most stringent bounds on Lorentz violation to date.