A Bayesian Framework to Investigate Radiation Reaction in Strong Fields

TL;DR

This paper introduces a Bayesian inference framework to accurately determine collision parameters in strong-field QED experiments, enabling better model validation and robustness despite measurement limitations.

Contribution

The novel Bayesian method allows inference of unmeasured collision parameters and combines multiple diagnostics for strong-field QED experiments.

Findings

The framework accurately infers collision parameters in simulated tests.

It effectively compares classical and quantum radiation reaction models.

The method is robust to discrepancies between experimental and model parameters.

Abstract

Recent experiments aiming to measure phenomena predicted by strong field quantum electrodynamics have done so by colliding relativistic electron beams and high-power lasers. In such experiments, measurements of the collision parameters are not always feasible, however, precise knowledge of these parameters is required for accurate tests of strong-field quantum electrodynamics. Here, we present a novel Bayesian inference procedure which infers collision parameters that could not be measured on-shot. This procedure is applicable to all-optical non-linear Compton scattering experiments investigating radiation reaction. The framework allows multiple diagnostics to be combined self-consistently and facilitates the inclusion of prior or known information pertaining to the collision parameters. Using this Bayesian analysis, the relative validity of the classical, quantum-continuous and quantum-stochastic models of radiation reaction were compared for a series of test cases, which demonstrate the accuracy and model selection capability of the framework and and highlight its robustness in the event that the experimental values of fixed parameters differ from their values in the models.