Yukawa Black Holes from Interacting Vacuum

TL;DR

This paper derives an exact solution to Einstein's equations with an interacting vacuum and electromagnetic field, revealing Yukawa potential effects and conditions for black hole horizons, including superluminal photon velocities near the horizon.

Contribution

It introduces a novel exact solution with vacuum-electromagnetic interaction leading to Yukawa potential effects in black hole spacetimes.

Findings

Black hole solutions with inner and outer horizons.

Superluminal photon velocities near the event horizon.

Photon rest mass linked to interaction coupling parameter.

Abstract

In this paper we obtain an exact solution of Einstein field equations assuming an interaction between a vacuum component and the Maxwell field. The key feature of such interaction refers to a simple stress exchange so that the electromagnetic field naturally incorporates the Yukawa potential. It is shown that the resulting spacetime thus obtained can either be a naked singularity or a black hole with an inner Cauchy horizon $R_-$ and an exterior event horizon $R_+$. For this latter configuration we examine the group velocity of test photons in the region $R>R_+$. Beyond a lower bound for the frequency we show that superluminal velocities arise in a neighbourhood of the event horizon and that the coupling parameter of the interaction is actually connected to a nonvanishing rest mass for the photon.