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Black hole stability in Einstein-Gauss-Bonnet gravity. In collaboration with Reinaldo Gleiser Class & Quant Gravity 22 (2005) L1 and gr-qc/0503117. Einstein-Gauss-Bonnet gravity. Special case of Lovelock gravity :. Some static, symmetric solutions. Cosmological solutions:.
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Black hole stability in Einstein-Gauss-Bonnet gravity In collaboration with Reinaldo Gleiser Class & Quant Gravity 22 (2005) L1 and gr-qc/0503117 Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
Einstein-Gauss-Bonnet gravity Special case of Lovelock gravity: Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
Some static, symmetric solutions Cosmological solutions: Black hole solutions: Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
Linear perturbations (h transverse traceless) Tensor type: Vector type: Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
Tensor linear perturbations get a (stationary) Schrödinger-like equation for negative E value in spectrum signals instability Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
S-deformation technique lower bound of Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
Found S deformed potential that factors Laplace-Beltrami eigenvalue out, and grows for higher harmonics , thus: Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
What about vector and scalar perturbations ? Vector mode: -Could work out the Schrödinger potential, up to spacetime dimension 11 -Found S-deformed potential that factors out harmonic eigenvalue in every case. -Analysis not done yet. Scalar mode: -Preliminary computations suggest there is no convenient S-deformation that gives a factored potential Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
Stability under tensor perturbations • Cosmological solutions found to be stable. • (positive string tension) BHs are stable if the spacetime • dimension is different from 6. • D = 6 BH instability: BHs with positive curvature horizons • are unstable if their masses are smaller than a critical value. • D = 6 BH instability: BHs with negative curvature horizons • are unstable if their masses are bigger than a critical value. Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005
Conclusions • Linearization of EGB gravity around symmetric static solutions give eqns that can be cast in Schrödinger form. • The Schrödinger potentials reproduce previously known results in the Einstein gravity limit. • For tensor and vector perturbations, S-deformed potentials can be found such that definite conclusions about stability can be arrived to in every case. This does not happen for scalar perturbations. • 6 dimensional BHs are special, there is a critical mass below (above) which those with positively (negatively) curved horizons become unstable. Problemas Actuales en Física de Gravitación - Córdoba - 28-05-2005