"Kerrr" black hole: the Lord of the String

TL;DR

This paper presents an exact, regular Kerr-like black hole solution without singularities or causality violations, achieved through noncommutative geometry inspired matter sources, offering a physically consistent rotating black hole model.

Contribution

It introduces a novel regular rotating black hole solution replacing the singularity with a classical string, avoiding unphysical features of traditional Kerr black holes.

Findings

No curvature ring singularity in the solution

Absence of causality-violating closed timelike curves

Smooth interpolation between Minkowski, deSitter, and Kerr geometries

Abstract

Kerrr in the title is not a typo. The third "r" stands for "regular", in the sense of pathology-free, rotating black hole. We exhibit a long search-for, exact, Kerr-like, solution of the Einstein equations with novel features: i) no curvature ring singularity; ii) no "anti-gravity" universe with causality violating timelike closed world-lines; iii) no "super-luminal" matter disk. The ring singularity is replaced by a classical, circular, rotating string with Planck tension representing the inner engine driving the rotation of all the surrounding matter. The resulting geometry is regular and smoothly interpolates among inner Minkowski space, borderline deSitter and outer Kerr universe. The key ingredient to cure all unphysical features of the ordinary Kerr black hole is the choice of a "noncommutative geometry inspired" matter source as the input for the Einstein equations, in analogy with spherically symmetric black holes described in earlier works.