Shockwaves and Time Delays in Einstein-Maxwell Effective Field Theory

TL;DR

This paper derives charged shockwave solutions in Einstein-Maxwell EFT, showing that EFT corrections affect the geometry and photon time delays, highlighting the importance of backreaction and field redefinition invariance.

Contribution

It introduces the first derivation of charged shockwaves in Einstein-Maxwell EFT including leading order corrections, revealing nontrivial EFT effects absent in neutral cases.

Findings

Charged shockwaves receive nontrivial EFT corrections.

Both geometry correction and backreaction are essential for physical time delay.

Time delay invariance under field redefinitions is confirmed.

Abstract

We derive the shockwave metric in four-dimensional Einstein-Maxwell effective field theory (EFT) by performing an ultra-relativistic boost of the charged black hole solution accompanied by a rescaling of its mass and charge, including leading order EFT corrections. In contrast to the neutral (Schwarzschild) case, where higher derivative operators leave the shockwave geometry unchanged, we show that electrically charged shockwaves receive nontrivial EFT corrections. We then compute the time delay experienced by a probe photon traversing the resulting charged shockwave. We find that two EFT contributions, the correction to the shockwave geometry and the backreaction induced by the probe photon, are both essential for obtaining a physical time delay that is invariant under field redefinitions of the metric.