Low-energy electromagnetic radiation as an indirect probe of black-hole evaporation

TL;DR

This paper investigates how black-hole evaporation affects low-energy light propagation using non-linear QED, revealing modifications to light speed and deflection angles that differ from general relativity predictions for certain black-hole masses.

Contribution

It introduces a framework combining black-hole evaporation effects with non-linear QED to analyze light propagation modifications.

Findings

Light-cone condition is altered for low-energy radiation.

Phase velocity can exceed the speed of light under certain conditions.

Deflection angle differs significantly from GR predictions for specific black-hole masses.

Abstract

We study the influence of black-hole evaporation on light propagation. The framework employed is based on the non-linear QED effective action at one-loop level. We show that the light-cone condition is modified for low-energy radiation due to black-hole evaporation. We discuss conditions under which the phase velocity of this low-energy radiation is greater than $c$. We also compute the modified light-deflection angle, which turns out to be significantly different from the standard GR value for black-hole masses in the range $M_\text{Pl} \ll M \lesssim 10^{19}\;M_\text{Pl}$.