Quantum-stochasticity-induced asymmetry in angular distribution of electrons in a quasi-classical regime

TL;DR

This paper demonstrates that quantum stochasticity can induce a detectable asymmetry in the angular distribution of electrons in ultra-intense laser-electron interactions, revealing quantum effects in a quasi-classical regime.

Contribution

It reveals that quantum stochasticity causes asymmetry in electron angular distribution under specific initial divergence conditions, a novel insight into quantum radiation reaction effects.

Findings

Asymmetry appears when initial divergence $ extless 10^{-6} a_0^2$.

Asymmetry is robust across various laser and electron parameters.

Quantum stochasticity effects are experimentally detectable with current technology.

Abstract

Impacts of quantum stochasticity on the dynamics of an ultra-relativistic electron beam head-on colliding with a linearly polarized ultra-intense laser pulse are theoretically investigated in a quasi-classical regime. Generally, the angular distribution of the electron beam keeps symmetrically in transverse directions in this regime, even under the ponderomotive force of the laser pulse. Here we show that when the initial angular divergence $\Delta \theta_i \lesssim 10^{-6} a_0^2$ with $a_0$ being the normalized laser field amplitude, an asymmetric angular distribution of the electron beam arises due to the quantum stochasticity effect, via simulations employing Landau-Lifshitz, quantum-modified Landau-Lifshitz equations, and quantum stochastic radiation reaction form to describe the radiative electron dynamics respectively. The asymmetry is robust against a variety of laser and electron parameters, providing an experimentally detectable signature for the nature of quantum stochasticity of photon emission with laser and electron beams currently available.