Some remarks on an old problem of radiation and gravity

TL;DR

This paper examines the longstanding problem of radiation from charged particles in gravitational fields, questioning the universality of the equivalence principle and proposing solutions that incorporate motional currents and magnetic effects.

Contribution

It offers a new perspective on radiation in gravitational fields, emphasizing the importance of motional currents and magnetic components, and calls for a reevaluation of free fall universality for charged particles.

Findings

Radiation depends on motional currents and magnetic effects.

Static particles in gravitational fields do not radiate, unlike accelerating charges.

A need for a revised understanding of the equivalence principle for charged particles.

Abstract

The assumed universality of the equivalence principle suggests that a particle in a gravitational field has identical physics to one in an accelerated frame. Yet, energy considerations prohibit radiation from a static particle in a gravitational field while the accelerating counterpart emits. Solutions to the fundamental problems of radiation from charges in a gravitational field and consequences to the equivalence principle usually contrast the far-field and global nature of radiation with the local validity of the equivalence principle. Here, we suggest reliable physical solutions that recognizes the essential need for motional currents and the magnetic component for radiation to occur. Our discussion reiterates the need for a fresh careful look at universality of free fall for charged particles in a gravitational field.