"Twisted" black holes are unphysical
Abstract
So-called "twisted" black holes have recently been proposed by Zhang (1609.09721 [gr-qc]), and further considered by Chen and Jing (1610.00886 [gr-qc]), and more recently by Ong (1610.05757 [gr-qc]). While these spacetimes are certainly Ricci-flat, and so mathematically satisfy the vacuum Einstein equations, they are also merely minor variants on Taub--NUT spacetimes. Consequently they exhibit several unphysical features that make them quite unreasonable as realistic astrophysical objects. Specifically, these "twisted" black holes are not (globally) asymptotically flat. Furthermore, they contain closed timelike curves that are not hidden behind any event horizon --- the most obvious of these closed timelike curves are small azimuthal circles around the rotation axis, but the effect is more general. The entire region outside the horizon is infested with closed timelike curves.
Keywords
Cite
@article{arxiv.1610.06135,
title = {"Twisted" black holes are unphysical},
author = {Finnian Gray and Jessica Santiago and Sebastian Schuster and Matt Visser},
journal= {arXiv preprint arXiv:1610.06135},
year = {2017}
}
Comments
10 pages