Robust signatures of quantum radiation reaction in focused ultrashort laser pulses

TL;DR

This paper demonstrates that quantum radiation reaction effects in electron-laser interactions produce distinct, measurable signatures in Compton scattering spectra, which are robust across various parameters and differ from classical predictions.

Contribution

It provides the first detailed analysis of quantum radiation reaction signatures in focused ultrashort laser pulses using a semi-classical and quantum approach.

Findings

Quantum radiation reaction signatures are visible in angular and spectral features.

These signatures are robust against parameter variations.

Quantum signatures differ qualitatively from classical predictions.

Abstract

Radiation reaction effects in the interaction of an electron bunch with a superstrong focused ultrashort laser pulse are investigated in the quantum radiation dominated regime. The angle-resolved Compton scattering spectra are calculated in laser pulses of variable duration using a semi-classical description for the radiation dominated dynamics and a full quantum treatment for the emitted radiation. In dependence of the laser pulse duration we find signatures of quantum radiation reaction in the radiation spectra, which are characteristic for the focused laser beam and visible in the qualitative behaviour of both the angular spread and the spectral bandwidth of the radiation spectra. The signatures are robust with respect to the variation of the electron and laser beam parameters in a large range. They fully differ qualitatively from those in the classical radiation reaction regime and are measurable with presently available laser technology.