The Graviton Tail almost Completely Wags the Dog

TL;DR

This paper investigates how graviton loop corrections in de Sitter space influence electromagnetic phenomena, revealing that certain infrared effects are solely due to the graviton propagator's tail term, impacting quantum gravity approaches.

Contribution

It demonstrates that the secular enhancement of the photon electric field strength is entirely due to the tail term of the graviton propagator, clarifying the origin of infrared effects in quantum gravity.

Findings

Secular enhancement of photon electric field strength from tail term.

Long-range Coulomb potential running not from tail term.

Implications for quantum gravity and inflationary quantum field theory.

Abstract

One graviton loop corrections to the vacuum polarization on de Sitter show two interesting infrared effects: a secular enhancement of the photon electric field strength and a long range running of the Coulomb potential. We show that the first effect derives solely from the "tail" term of the graviton propagator, but that the second effect does not. Our result agrees with the earlier observation that the secular enhancement of massless fermion mode functions derives from solely from the tail term. We discuss the implications this has for the important project of generalizing to quantum gravity the Starobinsky technique for summing the series of leading infrared effects from inflationary quantum field theory.