Quantum corrections to frame-dragging in scattering amplitudes

TL;DR

This paper calculates quantum corrections to the gravitational Faraday rotation effect in scattering amplitudes, revealing differences between electromagnetic and gravitational waves that suggest potential revisions to the equivalence principle at the quantum level.

Contribution

It provides the first computation of quantum corrections to frame-dragging effects using scattering amplitudes within an effective field theory approach.

Findings

Classical rotation angle is universal, consistent with the equivalence principle.

Quantum corrections differ between electromagnetic and gravitational waves.

Results suggest the need to reformulate the equivalence principle in quantum regimes.

Abstract

Frame-dragging effect manifests itself as polarization direction rotation when linearly polarized electromagnetic/gravitational wave scatters from a spinning point source through gravitational interactions, an effect also known as the gravitational Faraday rotation. Treating general relativity as an effective field theory, the Faraday rotation angle and its quantum corrections are computed using scattering amplitudes. While the classical rotation angle is universal as expected from the equivalence principle, the quantum corrections are found to be different between electromagnetic and gravitational waves, supporting earlier studies that some formulations of the equivalence principle may need reformulation in the quantum regime.