Many accelerating black holes

TL;DR

This paper demonstrates how the Weyl formalism can be used to construct exact solutions describing multiple collinear accelerating black holes with arbitrary masses and accelerations, connected by cosmic strings or struts.

Contribution

It provides a method to generate explicit metrics for multiple accelerating black holes with diverse parameters, extending previous solutions to arbitrary numbers of black holes.

Findings

Explicit metrics for two and three black holes with arbitrary parameters.

Conditions under which black holes are accelerated by strings or gravity.

Conjecture for solutions with any number of black holes.

Abstract

We show how the Weyl formalism allows metrics to be written down which correspond to arbitrary numbers of collinear accelerating neutral black holes in 3+1 dimensions. The black holes have arbitrary masses and different accelerations and share a common acceleration horizon. In the general case, the black holes are joined by cosmic strings or struts that provide the necessary forces that, together with the inter black hole gravitational attractions, produce the acceleration. In the cases of two and three black holes, the parameters may be chosen so that the outermost black hole is pulled along by a cosmic string and the inner black holes follow behind accelerated purely by gravitational forces. We conjecture that similar solutions exist for any number of black holes.