Electrodynamic Effects of Inflationary Gravitons

TL;DR

This paper computes one-loop quantum corrections from inflationary gravitons to electromagnetic fields in de Sitter space, revealing how inflation affects electric and magnetic sources differently over time and space.

Contribution

It provides the first detailed calculation of inflationary graviton effects on electromagnetic fields, highlighting new fractional corrections and observer-dependent perceptions.

Findings

Co-moving observer sees charge increase linearly over time.

Static observer detects no secular change in charge.

Magnetic dipole moment shows secular enhancement for static observer.

Abstract

We calculate the one-loop corrections from inflationary gravitons to the electromagnetic fields of a point charge and a point magnetic dipole on a locally de Sitter space background. Results are obtained both for an observer at rest in co-moving coordinates, whose physical distance from the sources increases with the expanding universe, and for an observer at rest in static coordinates, whose physical distance from the sources is constant. The fields of both sources show the de Sitter analogs of the fractional $G/r^2$ corrections which occur in flat space, but there are also some fractional $G H^2$ corrections due to the scattering of virtual photons from the vast ensemble of infrared gravitons produced by inflation. The co-moving observer perceives the magnitude of the point charge to increase linearly with co-moving time and logarithmically with the co-moving position, however, the magnetic dipole shows only a negative logarithmic spatial variation. The static observer perceives no secular change of the point charge but he does report a secular enhancement of the magnetic dipole moment.