Interaction of photons traversing a slowly varying electromagnetic background

TL;DR

This paper investigates how photon-photon interactions, like birefringence and four-wave mixing, intensify during the overlap of counterpropagating electromagnetic fields, highlighting implications for constant background assumptions.

Contribution

It provides new insights into the dynamic evolution of photon-photon scattering effects during field overlap, challenging the common static background approximation.

Findings

Photon-photon scattering effects increase significantly during field overlap

Birefringence and four-wave mixing are enhanced during interaction

Results impact calculations assuming constant electromagnetic backgrounds

Abstract

When two electromagnetic fields counterpropagate, they are modified due to mutual interaction via the polarised virtual electron-positron states of the vacuum. By studying how photon-photon scattering effects such as birefringence and four-wave mixing evolve as the fields pass through one another, we find a significant increase during overlap. The results have particular relevance for calculations based on a constant field background.