2024/08/23 by S. V. Bolokhov, К. А. Бронников, K. A. Bronnikov +1
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Black hole (networking) #Center (category theory) #Classical mechanics #Cosmology and Gravitation Theories #General relativity #Geometry #Gravitational singularity #Mathematical analysis #Mathematical physics #Mathematics #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Scalar (mathematics) #Scalar field #Schwarzschild metric #Schwarzschild radius #Singularity #Spacetime #Wormhole
paper · doi:10.1134/s0202289324700178
crossref issued 2024/08/23 · crossref published 2024/08/23 · crossref published-online 2024/08/23 · openalex publication_date 2024/08/23 · crossref created 2024/08/23 · crossref published-print 2024/09/01 · openalex created_date 2025/10/10 · crossref deposited 2026/03/23 · openalex updated_date 2026/08/04 · crossref indexed 2026/08/04
The widely discussed “black-bounce” mechanism of removing a singularity at r=0 in a spherically symmetric space-time, proposed by Simpson and Visser, consists in removing the point r=0 and its close neighborhood, resulting in emergence of a regular minimum of the spherical radius that can be a wormhole throat or a regular bounce. Instead, it has been recently proposed to make r=0 a regular center by properly modifying the metric, still preserving its form in regions far from r=0 . Different algorithms of such modifications have been formulated for a few classes of singularities. The previous paper considered space-times whose Ricci tensor satisfies the condition Rtt=Rrr , and regular modifications were obtained for the Schwarzschild, Reissner-Nordström metrics, and two examples of solutions with magnetic fields obeying nonlinear electrodynamics (NED). The present paper considers regular modifications of more general space-times, and as examples, modifications with a regular center have been obtained for the Fisher (also known as JNW) solution with a naked singularity and a family of dilatonic black holes. Possible field sources of the new regular metrics are considered in the framework of general relativity (GR), using the fact that any static, spherically symmetric metric can be presented as a solution with a combined source involving NED and a scalar field with some self-interaction potential. This scalar field is, in general, not required to be of phantom nature (unlike the sources for black bounces), but in the examples discussed here, the possible scalar sources are phantom in a close neighborhood of r=0 and are canonical outside it.