Prism Effect in Quantum Gravity
arXiv:2607.13012
The paper develops a general framework using an extended Born-Oppenheimer approximation to describe how electromagnetic waves propagate in a quantum‑gravity-modified spacetime, predicting prism‑like chromatic dispersion effects even at high energies.
Abstract
Modifications to the dispersion relation of electromagnetic (EM) waves are a central probe in the search for quantum gravitational effects. In this work, we construct a general framework for the interaction between the EM field and a quantum background geometry, employing an extended Born-Oppenheimer approximation. This leads to a quasi-phenomenological model for EM wave propagation in curved spacetime. Unlike previous semi-classical approaches for mode-dependent dispersion relations, our framework naturally reproduces chromatic dispersion effects analogous to those observed in light-matter interactions in nonlinear optics. As a concrete application, we analyze EM wave propagation on a flat quantum Friedmann-Lemaitre-Robertson-Walker (FLRW) background, combining analytical techniques with numerical simulations to extract observable signatures of the prism-like behavior induced by quantum light-geometry interactions. Crucially, it remains valid across all energy regimes, enabling access to quantum gravitational corrections beyond the semi-classical limit.
7 pages, 6 figures, references and template has been updated