One loop graviton corrections to dynamical photons in de Sitter

Abstract

We employ a recent, general gauge computation of the one loop graviton contribution to the vacuum polarization on de Sitter to solve for one loop corrections to the photon mode function. The vacuum polarization takes the form of a gauge independent, spin 2 contribution and a gauge dependent, spin 0 contribution. We show that the leading secular corrections derive entirely from the spin 2 contribution.

One loop corrected conformally coupled scalar mode equations during inflation

“…• For quantum gravity plus electrodynamics, inflationary gravitons induce secular effects on the dynamical photons and alter the electric field of a point charge and the magnetic field of a point magnetic dipole [24][25][26][27][28][29][30].…”

Graviton propagator in a 2-parameter family of de Sitter breaking gauges

“…where the coefficients of these expansions can be read off by comparing (56) to the power series of the scalar propagators (15)(16)(17),…”

“…and where ψ(z) = Γ ′ (z)/Γ(z) is the digamma function. Note that some coefficients from the integer series depend linearly on u = ln(aa ′ ), and that this dependence descends from the de Sitter breaking part of the A-type propagator (15). Since the equations for the coefficients of the non-integer power series (57) decouple from the equations for the integer ones, we solve for them separately in the following subsections.…”

Deducing cosmological observables from the S matrix

“…• Inflationary gravitons secularly excite photons as they do fermions [11,12,13,14], and they also induce secular modifications of electrodynamic forces [15];…”