"Kerrr" black hole: the Lord of the String

Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste, Italy
Physics Letters B (Impact Factor: 6.13). 04/2010; 688(1):82-87. DOI: 10.1016/j.physletb.2010.03.075
Source: arXiv


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 time-like 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 de Sitter and outer Kerr universe. The key ingredient to cure all unphysical features of the ordinary Kerr black hole is the choice of a “non-commutative geometry inspired” matter source as the input for the Einstein equations, in analogy with spherically symmetric black holes described in earlier works.

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    • "The UV finiteness of any non-local theory like that in (11) is guaranteed at any order only for a certain degree of convergence of the entire function A. According to the definition given in [62] [63], such a global convergence occurs for entire functions of order higher than 1/2. As an example, NCG inspired black holes [17] [18] [19] [64] [65] [66] [67] [68] [69] and the associated quantum field theory [70] [71] [72] are non-local formulations employing such a kind of entire function [20]. At the level of free fields the convergence is achieved also in the case of order 1/2. "
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    • "The above profile cures the usual Dirac delta (singular) distribution associated to a pointparticle , and leads to a family of regular black hole solutions [19] [20] [21] [22] [23] [24] [25] [26] [27] [28]. "
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    ABSTRACT: In the presence of a minimal length physical objects cannot collapse to an infinite density, singular, matter point. In this note we consider the possible final stage of the gravitational collapse of "thick" matter layers. The energy momentum tensor we choose to model these shell-like objects is a proper modification of the source for "non-commutative geometry inspired", regular black holes. By using higher momenta of Gaussian distribution to localize matter at finite distance from the origin, we obtain new solutions of the Einstein's equation which smoothly interpolates between Minkowski geometry near the center of the shell and Schwarzschild spacetime far away from the matter layer. The metric is curvature singularity free. Black hole type solutions exist only for "heavy" shells, i.e. $M\ge M_{e}$, where $M_{e}$ is the mass of the extremal configuration. We determine the Hawking temperature and a modified Area Law taking into account the extended nature of the source.
    Advances in High Energy Physics 10/2011; 2013. DOI:10.1155/2013/812084 · 2.20 Impact Factor
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    • "NCBHs are the richest family of quantum gravity improved black hole space– 3 – times. There exist higher-dimensional static [76], charged [77], rotating [48] and charged rotating [78] NCBHs, the latter only for low angular momenta as is the case for classical black holes. Therefore NCBHs are the only ones that can currently provide a complete scenario and it is worth starting from them in view of future investigations. "
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    ABSTRACT: We address the issue of modelling quantum gravity effects in the evaporation of higher dimensional black holes in order to go beyond the usual semi-classical approximation. After reviewing the existing six families of quantum gravity corrected black hole geometries, we focus our work on non-commutative geometry inspired black holes, which encode model independent characteristics, are unaffected by the quantum back reaction and have an analytical form compact enough for numerical simulations. We consider the higher dimensional, spherically symmetric case and we proceed with a complete analysis of the brane/bulk emission for scalar fields. The key feature which makes the evaporation of non-commutative black holes so peculiar is the possibility of having a maximum temperature. Contrary to what happens with classical Schwarzschild black holes, the emission is dominated by low frequency field modes on the brane. This is a distinctive and potentially testable signature which might disclose further features about the nature of quantum gravity.
    Journal of High Energy Physics 08/2011; 11(11). DOI:10.1007/JHEP11(2011)075 · 6.11 Impact Factor
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