Towards nonsingular rotating compact object in ghost-free infinite derivative gravity

Buoninfante, Luca; Cornell, Alan S.; Harmsen, Gerhard; Koshelev, Alexey S.; Lambiase, Gaetano; Marto, João; Mazumdar, Anupam

doi:10.1103/physrevd.98.084041

Cited by 74 publications

(73 citation statements)

References 82 publications

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“…However, it is reasonable to assume that, once that quantum gravity effect are taken into account, singularities will be regularized. The structure and properties of the corresponding non-singular black holes is largely unknown, in part due to our lack of knowledge about the dynamics in quantum gravity, although there have been many and diverse attempts at constructing geometries or toy models that aim at capturing the leading effects beyond general relativity [5][6][7][8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Geodesically complete black holes

et al. 2020

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The 1965 Penrose singularity theorem demonstrates the utterly inevitable and unavoidable formation of spacetime singularities under physically reasonable assumptions, and it remains one of the main results in our understanding of black holes. It is standard lore that quantum gravitational effects will always tame these singularities in black hole interiors. However, the Penrose's theorem provides no clue as to the possible (non-singular) geometries that may be realized in theories beyond general relativity as the result of singularity regularization. In this paper we analyze this problem in spherically symmetric situations, being completely general otherwise, in particular regarding the dynamics of the gravitational and matter fields. Our main result is that, contrary to what one might expect, the set of regular geometries that arises is remarkably limited. We rederive geometries that have been analyzed before, but also uncover some new possibilities. Moreover, the complete catalogue of possibilities that we obtain allows us to draw the novel conclusion that there is a clear tradeoff between internal and external consistency: One has to choose between models that display internal inconsistencies, or models that include significant deviations with respect to general relativity, which should therefore be amenable to observational tests via multi-messenger astrophysics. CONTENTS

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Section: Introductionmentioning

confidence: 99%

Geodesically complete black holes

et al. 2020

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“…[12,13] where it was shown that higher derivative gauge theories can be made ghost-free. In the gravitational context the same class of nonlocal actions were useful to obtain ghost-free nonsingular cosmological [14][15][16][17][18] and blackhole [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] solutions. Such nonlocal models were also applied in the framework of inflationary cosmology [34], and thermal field theory [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Nonlocal star as a blackhole mimicker

Buoninfante

Mazumdar

2019

Phys. Rev. D

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In the context of ghost-free, infinite derivative gravity, we will provide a quantum mechanical framework in which we can describe astrophysical objects devoid of curvature singularity and event horizon. In order to avoid ghosts and singularity, the gravitational interaction has to be nonlocal, therefore, we call these objects as nonlocal stars. Quantum mechanically a nonlocal star is a selfgravitational bound system of many gravitons interacting nonlocally. Outside the nonlocal star the spacetime is well described by the Schwarzschild metric, while inside we have a non-vacuum spacetime metric which tends to be conformally flat at the origin. Remarkably, in the most compact scenario the radius of a nonlocal star is of the same order of the Buchdahl limit, therefore slightly larger than the Schwarzschild radius, such that there can exist a photosphere. These objects live longer than a Schwarzschild blackhole and they are very good absorbers, due to the fact that the number of available states is larger than that of a blackhole. As a result nonlocal stars, not only can be excellent blackhole mimickers, but can also be considered as dark matter candidates. In particular, nonlocal stars with masses below 10 14 g can be made stable compared to the age of the Universe.

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“…It is a direct manifestation of the non-trivial nature of quantum vacuum [20], which occurs whenever a quantum field is bounded in a finite region of space; such a confinement gives rise to a net attractive force between the confining plates, whose intensity has been successfully measured [21]. Since the foundational paper [22], the Casimir effect has been largely investigated in both flat [23] and curved [24] background, and in particular in quadratic theories of gravity [25], which have been studied also in other frameworks [26]. Further interesting applications have been addressed in the context of Lorentz symmetry breaking [27] and flavor mixing of fields [28].…”

Section: Introductionmentioning

confidence: 99%