Spin and polarisation dependent LCFA rates for nonlinear Compton and Breit-Wheeler processes

TL;DR

This paper derives and discusses spin- and polarization-dependent probability rates for nonlinear Compton scattering and Breit-Wheeler pair production within the locally constant field approximation, crucial for plasma-QED simulations.

Contribution

It provides a rigorous derivation of spin- and polarization-dependent rates from strong-field QED matrix elements for general plane-wave backgrounds, including asymptotic limits.

Findings

Polarisation correlation effects are significant in the spectra.

Asymptotic behaviors for small and large  are characterized.

The results enhance accuracy in plasma-QED simulations.

Abstract

In this paper we derive and discuss the completely spin- and photon-polarisation dependent probability rates for nonlinear Compton scattering and nonlinear Breit-Wheeler pair production. The locally constant field approximation, which is essential for applications in plasma-QED simulation codes, is rigorously derived from the strong-field QED matrix elements in the Furry picture for a general plane-wave background field. We discuss important polarisation correlation effects in the spectra of both processes. Asymptotic limits for both small and large values of $\chi$ are derived and their spin/polarisation dependence is discussed.