- Jan 27, 2020
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By Antonio De Felice (1 )and Shinji Tsujikawa (2)
1. Center for Gravitational Physics and Quantum Information,
Yukawa Institute for Theoretical Physics, Kyoto University, 606-8502, Kyoto, Japan
2. Department of Physics, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan (Dated: May 15, 2023
Einsteinian cubic gravity is a higher-order gravitational theory in which the linearized field equa- tions of motion match Einstein’s equations on a maximally symmetric background. This theory allows the existence of a static and spherically symmetric black hole solution where the temporal and radial metric components are equivalent to each other (f = h), with a modified Schwarzschild geometry induced by cubic curvature terms. We study the linear stability of static and spheri- cally symmetric vacuum solutions against odd-parity perturbations without imposing the condition f = h. Unlike General Relativity containing one dynamical perturbation, Einsteinian cubic gravity has three propagating degrees of freedom in the odd-parity sector. We show that at least one of those dynamical perturbations always behaves as a ghost mode. We also find that, in the regime where the effective field theory is valid, one dynamical degree of freedom has a negative sound speed squared −1/2 for the propagation of high angular momentum modes. Thus, any static and spher- ically symmetric vacuum solutions present in Einsteinian cubic gravity, which includes the black hole solution with f = h, are excluded by ghost and Laplacian instabilities.
For the remainder of the article,
See: https://arxiv.org/pdf/2305.07217.pdf
Einsteinian cubic gravity unveils two further surprising features. The charged black holes do not possess an inner horizon, in contrast with the usual Reissner-Nordström spacetime, thus avoiding the need to resort to strong cosmic censorship to uphold determinism. In addition to black holes, there exists a one-parameter family of naked singularity spacetimes sharing the same mass and charge as the former, but not continuously connected with them. These naked singularities exist in the under-extremal regime, being present even in pure (uncharged) Einsteinian cubic gravity.
Hartmann352
1. Center for Gravitational Physics and Quantum Information,
Yukawa Institute for Theoretical Physics, Kyoto University, 606-8502, Kyoto, Japan
2. Department of Physics, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan (Dated: May 15, 2023
Einsteinian cubic gravity is a higher-order gravitational theory in which the linearized field equa- tions of motion match Einstein’s equations on a maximally symmetric background. This theory allows the existence of a static and spherically symmetric black hole solution where the temporal and radial metric components are equivalent to each other (f = h), with a modified Schwarzschild geometry induced by cubic curvature terms. We study the linear stability of static and spheri- cally symmetric vacuum solutions against odd-parity perturbations without imposing the condition f = h. Unlike General Relativity containing one dynamical perturbation, Einsteinian cubic gravity has three propagating degrees of freedom in the odd-parity sector. We show that at least one of those dynamical perturbations always behaves as a ghost mode. We also find that, in the regime where the effective field theory is valid, one dynamical degree of freedom has a negative sound speed squared −1/2 for the propagation of high angular momentum modes. Thus, any static and spher- ically symmetric vacuum solutions present in Einsteinian cubic gravity, which includes the black hole solution with f = h, are excluded by ghost and Laplacian instabilities.
For the remainder of the article,
See: https://arxiv.org/pdf/2305.07217.pdf
Einsteinian cubic gravity unveils two further surprising features. The charged black holes do not possess an inner horizon, in contrast with the usual Reissner-Nordström spacetime, thus avoiding the need to resort to strong cosmic censorship to uphold determinism. In addition to black holes, there exists a one-parameter family of naked singularity spacetimes sharing the same mass and charge as the former, but not continuously connected with them. These naked singularities exist in the under-extremal regime, being present even in pure (uncharged) Einsteinian cubic gravity.
Hartmann352
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