On the Black Hole Acceleration in the C-metric Space-time

TL;DR

This paper investigates the acceleration of black holes in the C-metric spacetime using teleparallel gravity, revealing that negative energy from a cosmic string may drive the black hole's acceleration.

Contribution

It provides a novel explanation for black hole acceleration based on gravitational energy calculations within the TEGR framework.

Findings

Gravitational energy within the horizon is proportional to the square root of the horizon area.

The gravitational energy of the cosmic string is negative and dominates at large distances.

Negative energy may be responsible for the black hole’s acceleration along the string.

Abstract

We consider the C-metric as a gravitational field configuration that describes an accelerating black hole in the presence of a semi-infinite cosmic string, along the accelerating direction. We adopt the expression for the gravitational energy-momentum developed in the teleparallel equivalent of general relativity (TEGR) and obtain a possible explanation for the acceleration of the black hole. The gravitational energy enclosed by surfaces of constant radius around the black hole is evaluated, and in particular the energy contained within the gravitational horizon is obtained. This energy turns out to be proportional to the square root of the area of the horizon. We find that the gravitational energy of the semi-infinite cosmic string is negative and dominant for large values of the radius of integration. This negative energy may explain the acceleration of the black hole, that moves towards regions of lower gravitational energy along the string.