A Regular Center Instead of a Black Bounce

IF 1.2 4区物理与天体物理 Q3 ASTRONOMY & ASTROPHYSICS Gravitation and Cosmology Pub Date : 2024-08-23 DOI:10.1134/s0202289324700178

S. V. Bolokhov, K. A. Bronnikov, M. V. Skvortsova

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Abstract

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 \(R^{t}_{t}=R^{r}_{r}\), 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.

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常规中心而非黑色弹跳

摘要辛普森（Simpson）和维瑟（Visser）提出的在球对称时空中消除奇点（r=0）的 "黑反弹 "机制引起了广泛讨论，该机制包括消除点（r=0）及其近邻，从而出现一个规则的球半径最小值，它可以是一个虫洞咽喉，也可以是一个规则的反弹。相反，最近有人提出通过适当修改度量，使\(r=0\)成为一个规则中心，同时在远离\(r=0\)的区域仍然保留其形式。针对几类奇点，人们提出了不同的修改算法。前一篇论文考虑了里奇张量满足条件\(R^{t}_{t}=R^{r}_{r}\)的时空，并得到了施瓦兹柴尔德、雷斯纳-诺德斯特伦度量以及两个服从非线性电动力学（NED）的磁场解的正则修正。本文考虑了更一般时空的正则修正，并以具有裸奇点的费雪（也称 JNW）解和稀释黑洞系列为例，给出了具有正则中心的修正。我们在广义相对论（GR）框架下考虑了新规则度量的可能场源，利用了这样一个事实，即任何静态球面对称度量都可以呈现为一种解，其组合源涉及 NED 和具有某种自相互作用势的标量场。一般来说，这个标量场不需要是幻影性质的（与黑色反弹的源不同），但在这里讨论的例子中，可能的标量源在\(r=0\)的近邻中是幻影的，而在它（r=0\）之外则是典型的。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Gravitation and Cosmology ASTRONOMY & ASTROPHYSICS-

CiteScore

1.70

自引率

22.20%

发文量

审稿时长

>12 weeks

期刊介绍： Gravitation and Cosmology is a peer-reviewed periodical, dealing with the full range of topics of gravitational physics and relativistic cosmology and published under the auspices of the Russian Gravitation Society and Peoplesâ€™ Friendship University of Russia. The journal publishes research papers, review articles and brief communications on the following fields: theoretical (classical and quantum) gravitation; relativistic astrophysics and cosmology, exact solutions and modern mathematical methods in gravitation and cosmology, including Lie groups, geometry and topology; unification theories including gravitation; fundamental physical constants and their possible variations; fundamental gravity experiments on Earth and in space; related topics. It also publishes selected old papers which have not lost their topicality but were previously published only in Russian and were not available to the worldwide research community

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