On Accelerated Black Holes

TL;DR

This paper revisits the properties of accelerated black holes, analyzing their horizons, thermodynamics, and singularities, and clarifies misconceptions about their bounds and extensions to rotating cases.

Contribution

It provides a detailed analysis of accelerated black holes, addressing their horizon structure, thermodynamic properties, and clarifying the coordinate artifact nature of certain bounds.

Findings

Accelerated static black holes exhibit conical singularities or non-smooth horizons.

Accelerated black holes have higher Hawking temperature than Unruh temperature.

The upper bound on mass and acceleration product is a coordinate artifact.

Abstract

The static and stationary C-metric are revisited in a generic framework and their interpretations studied in some detail. Specially those with two event horizons, one for the black hole and another for the acceleration. We found that: i) The spacetime of an accelerated static black hole is plagued by either conical singularities or lack of smoothness and compactness of the black hole horizon; ii) By using standard black hole thermodynamics we show that accelerated black holes have higher Hawking temperature than Unruh temperature of the accelerated frame; iii) The usual upper bound on the product of the mass and acceleration parameters <1/sqrt(27) is just a coordinate artifact. The main results are extended to accelerated rotating black holes with no significant changes.