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arXiv · 2209.01867

Instability of spherically-symmetric black holes in Quadratic Gravity

Aaron Held·Jun Zhang
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Abstract

We investigate the linear stability of the two known branches of spherically-symmetric black holes in Quadratic Gravity. We extend previous work on the long-wavelength (Gregory-Laflamme) instability of the Schwarzschild branch to a corresponding long-wavelength instability in the non-Schwarzschild branch. In both cases, the instability sets in below a critical horizon radius at which the two black-hole branches intersect. This suggests that classical perturbations enforce a lower bound on the horizon radius of spherically-symmetric black holes in Quadratic Gravity.

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Aaron Held, Jun Zhang. 2022-09-05. Instability of spherically-symmetric black holes in Quadratic Gravity. https://doi.org/10.1103/physrevd.107.064060

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