Monte Carlo challenges for strong field quantum electrodynamics
Anthony Hartin
TL;DR
The Schwinger effect and its assisted variant (OPPP) illustrate non-perturbative QED in strong fields, motivating a Monte Carlo approach to predict transition rates under realistic beam/laser conditions. The authors develop IPstrong, a 4D voxel-based event generator that combines PIC-style beam modeling with precomputed strong-field transition rates to simulate first- and second-order SQED processes, including harmonic Compton scattering, rest-mass shifts, and resonances. They validate IPstrong against analytic expectations for OPPP and HICS spectra and outline a pathway to incorporate higher-order resonances and three-beam experimental schemas. This tool is poised to aid the design, interpretation, and planning of upcoming strong-field, non-perturbative SQED experiments.
Abstract
The assisted Schwinger effect, which is predicted to display non-perturbative quantum tunnelling, is expected to be produced in precision lab experiments with electron beams and intense lasers. Indeed, many novel effects predicted by a theory which incorporates the laser field exactly, can be probed experimentally with the proper application of theory and simulation. Among predicted first order effects are a rest mass shift and harmonic Compton scattering. Higher order effects include resonant transition rates which become apparent when scanned over specific kinematic parameters. The underpinning of the theory and experiment is a Monte Carlo simulation tool which precisely links experimental realities to the expected theoretical transition rates. We report on the progress of such a tool here.