Narrowing of the emission angle in high-intensity Compton scattering

TL;DR

This paper compares quantum and classical predictions for the emission angle of high-energy electrons in intense laser fields, finding quantum theory predicts a narrower emission angle at high intensities due to differences in energy loss modeling.

Contribution

It demonstrates that quantum electrodynamics predicts a narrower emission angle than classical theory at high laser intensities, highlighting the importance of quantum effects in strong-field interactions.

Findings

Quantum theory predicts narrower emission angles at high intensities.

Classical theory overestimates energy loss, affecting emission angles.

Quantum effects become significant at $a_0 ext{~}200$ intensity levels.

Abstract

We consider the emission spectrum of high-energy electrons in an intense laser field. At high intensities ($a_0\sim200$) we find that the QED theory predicts a narrower angular spread of emissions than the classical theory. This is due to the classical theory overestimating the energy loss of the particles, resulting in them becoming more susceptible to reflection in the laser pulse.