Troubles with the radiation reaction in electrodynamics

TL;DR

This paper introduces a new model for the radiation reaction in electrodynamics that resolves longstanding issues with the classical LAD equation by incorporating a time delay, resulting in a pathology-free and testable equation.

Contribution

The paper proposes a novel model based on a time delay hypothesis that naturally addresses the pathologies of the LAD equation and connects to a quasi-local QED framework.

Findings

The new model removes the pathologies of the LAD equation.

It predicts a modified Larmor formula.

The modification is testable with ultra-intense lasers.

Abstract

The dynamics of a radiating charge is one of the oldest unsettled problems in classical physics. The standard Lorentz-Abraham-Dirac (LAD) equation of motion is known to suffer from several pathologies and ambiguities. This paper briefly reviews these issues, and reports on a new model that fixes these difficulties in a natural way. This model is based on a hypothesis that there is an infinitesimal time delay between action and reaction. This can be related to Feynman's regularization scheme, leading to a quasi-local QED with a natural UV cutoff, hence without the need for renormalization as the divergences are absent. Besides leading to a pathology-free equation of motion, the new model predicts a modification of the Larmor formula that is testable with current and near future ultra-intense lasers.