Gravity's Rainbow: Limits for the applicability of the equivalence principle

TL;DR

This paper investigates the boundaries of the equivalence principle within effective field theories, revealing how higher-derivative interactions can cause dispersive photon propagation and affect light deflection.

Contribution

It introduces a class of higher-derivative interactions that lead to dispersive photon propagation, expanding understanding of the limits of the equivalence principle.

Findings

Higher-derivative interactions cause dispersive photon propagation.

Energy-dependent effects alter light deflection.

Limits of the equivalence principle are characterized in this context.

Abstract

Limits for the applicability of the equivalence principle are considered in the context of low-energy effective field theories. In particular, we find a class of higher-derivative interactions for the gravitational and electromagnetic fields which produce dispersive photon propagation. The latter is illustrated by calculating the energy-dependent contribution to the deflection of light rays.