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

Slava Emelyanov

doi:10.1016/j.nuclphysb.2016.09.011

Slava Emelyanov

Open Access

https://doi.org/10.1016/j.nuclphysb.2016.09.011

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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 MPl≪M≲1019MPl.

Highlights

A propagation of light in a non-trivial, i.e. non-Minkowskian, quantum state can be modified in quantum electrodynamics (QED)
A low-energy electromagnetic wave propagating through a thermal gas turns out to be subluminal [1,2], while superluminal when propagating in-between conducting plates in the Casimir set-up [3]. These two effects can be described at the same time by considering the effective action of the electromagnetic field with integrated out fermion degrees of freedom [2]
We have analysed the influence of the vacuum polarisation induced by the black holes in quantum electrodynamics on the propagation of the low-energy electromagnetic radiation

Summary

Introduction

A propagation of light in a non-trivial, i.e. non-Minkowskian, quantum state can be modified in quantum electrodynamics (QED). A low-energy electromagnetic wave propagating through a thermal gas turns out to be subluminal [1,2], while superluminal when propagating in-between conducting plates in the Casimir set-up [3]. These two effects can be described at the same time by considering the effective action of the electromagnetic field with integrated out fermion degrees of freedom [2]. At the leading α-order these terms are quadratic with respect to the field strength of the electromagnetic field This implies in particular that the Drummond–Hathrell term is oblivious to the quantum state at the α-order approximation, but not to the spacetime geometry.

Effective field equations

Modified radial propagation

Modified light deflection

Two-loop dominance

Concluding remarks