Higher fidelity simulations of nonlinear Breit-Wheeler pair creation in intense laser pulses

TL;DR

This paper presents a high-fidelity simulation framework for nonlinear Breit-Wheeler pair creation in intense laser pulses, validating its accuracy against analytical results and exploring the transition from multi-photon to all-order pair production.

Contribution

The authors develop and validate a detailed simulation approach incorporating strong-field QED effects, improving accuracy over existing models for pair creation in intense laser fields.

Findings

Simulation accurately reproduces harmonic structures in spectra.

Transition from multi-photon to all-order pair creation is characterized.

Assessment of the locally constant field approximation's validity.

Abstract

When a photon collides with a laser pulse, an electron-positron pair can be produced via the nonlinear Breit-Wheeler process. A simulation framework has been developed to calculate this process, which is based on a ponderomotive approach that includes strong-field quantum electrodynamical effects via the locally monochromatic approximation (LMA). Here we compare simulation predictions for a variety of observables, in different physical regimes, with numerical evaluation of exact analytical results from theory. For the case of a focussed laser background, we also compare simulation with a high-energy theory approximation. These comparisons are used to quantify the accuracy of the simulation approach in calculating harmonic structure, which appears in the lightfront momentum and angular spectra of outgoing particles, and the transition from multi-photon to all-order pair creation. Calculation of the total yield of pairs over a range of intensity parameters is also used to assess the accuracy of the locally constant field approximation (LCFA).