Radiation from a uniformly accelerated charge in the outskirts of a wormhole throat

TL;DR

This paper investigates whether a uniformly accelerated charged particle radiates in a traversable wormhole spacetime, focusing on gravitational Cerenkov radiation and energy condition violations that affect light propagation.

Contribution

It explores the conditions under which gravitational Cerenkov radiation occurs near wormholes and links energy condition violations to superluminal propagation of particles.

Findings

Negative Ricci curvature leads to effective superluminal light speed.

Violating the weak energy condition enables gravitational Cerenkov radiation.

The equivalence principle is violated in these exotic spacetime conditions.

Abstract

Using traversable wormholes as theoretical background, we revisit a deep question of general relativity: Does a uniformly accelerated charged particle radiate? We particularize to the recently proposed gravitational \v{C}erenkov radiation, that happens when the spatial part of the Ricci tensor is negative. If $^{^{(3+1)}}R^i_{\phantom{i}i}< 0$, the matter threading the gravitational field violates the weak energy condition. In this case, the effective refractive index for light is bigger than 1, i.e. particles propagates, in that medium, faster than photons. This leads to a violation of the equivalence principle.