# The Abraham-Lorentz force and electrodynamics at the classical electron radius

## TL;DR

This paper explores the Abraham-Lorentz force in classical electrodynamics, addressing issues with UV singularities and regulators, and connects classical radiation reaction with quantum electrodynamics through effective theories.

## Contribution

It demonstrates that point splitting regulators can stabilize the Abraham-Lorentz force and links classical radiation reaction to quantum effective theories.

## Key findings

- Point splitting regulators stabilize the Abraham-Lorentz force.
- Classical radiation reaction can be derived from quantum effective theories.
- Relativistic cutoff theories have unbounded energy from below.

## Abstract

The Abraham-Lorentz force is a finite remnant of the UV singular structure of the self interaction of a point charge with its own field. The satisfactory description of such interaction needs a relativistic regulator. This turns out to be a problematic point because the energy of regulated relativistic cutoff theories is unbounded from below. However one can construct point splitting regulators which keep the Abraham-Lorentz force stable. The classical language can be reconciled with QED by pointing out that the effective quantum theory for the electric charge supports a saddle point producing the classical radiation reaction forces.