# Radiation rebound and Quantum Splash in Electron-Laser Collision

## TL;DR

This paper investigates how radiation reaction influences electron-laser collisions, revealing distinct classical and quantum signatures through theoretical and simulation analyses, and proposes a method to distinguish these regimes.

## Contribution

It introduces a novel approach to differentiate classical and quantum radiation reaction effects in electron-laser interactions using threshold behaviors and scattering signatures.

## Key findings

- Classical RR causes a sharp threshold for electron rebound.
- Quantum RR results in quasi-isotropic electron scattering.
- A practical detection method to distinguish RR regimes is proposed.

## Abstract

The radiation reaction (RR) is expected to play a critical role in light-matter interactions at extreme intensity. Utilizing the theoretical analyses and three-dimensional (3D) numerical simulations, we demonstrate that electron reflection, induced by the RR in a head-on collision with an intense laser pulse, can provide pronounced signatures to discern the classical and quantum RR. In the classical regime, there is a precipitous threshold of laser intensity to achieve the whole electron bunch rebound. However, this threshold becomes a gradual transition in the quantum regime, where the electron bunch is quasi-isotropically scattered by the laser pulse and this process resembles a water splash. Leveraged on the derived dependence of classical radiation rebound on the parameters of laser pulses and electron bunches, a practical detecting method is proposed to distinguish the quantum discrete recoil and classical continuous RR force.

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Source: https://tomesphere.com/paper/1901.07965