New Black Hole Solutions in Brans-Dicke Theory of Gravity

TL;DR

This paper investigates the existence of non-trivial black hole solutions in Brans-Dicke gravity, finding Kerr-Newman-like solutions with scalar hair for certain parameter ranges, and discusses their physical implications.

Contribution

It demonstrates the existence of new black hole solutions in Brans-Dicke theory that differ from general relativity, especially for specific parameter values, and explores their physical significance.

Findings

Non-trivial Kerr-Newman-type solutions exist for -5/2 ≤ ω < -3/2.

These solutions may carry scalar hair.

Potential physical implications of these black holes are discussed.

Abstract

Existence check of non-trivial, stationary axisymmetric black hole solutions in Brans-Dicke theory of gravity in different direction from those of Penrose, Thorne and Dykla, and Hawking is performed. Namely, working directly with the known explicit spacetime solutions in Brans-Dicke theory, it is found that non-trivial Kerr-Newman-type black hole solutions different from general relativistic solutions could occur for the generic Brans-Dicke parameter values -5/2\leq \omega <-3/2. Finally, issues like whether these new black holes carry scalar hair and can really arise in nature and if they can, what the associated physical implications would be are discussed carefully.