Stability of scalarized black hole solutions in scalar-Gauss-Bonnet gravity

Hector O. Silva, Caio F.B. Macedo, Thomas P. Sotiriou, Leonardo Gualtieri, Jeremy Sakstein, Emanuele Berti

Research output: Contribution to journalArticlepeer-review

Abstract

Scalar-tensor theories of gravity where a new scalar degree of freedom couples to the Gauss-Bonnet invariant can exhibit the phenomenon of spontaneous black hole scalarization. These theories admit both the classic black hole solutions predicted by general relativity as well as novel hairy black hole solutions. The stability of hairy black holes is strongly dependent on the precise form of the scalar-gravity coupling. A radial stability investigation revealed that all scalarized black hole solutions are unstable when the coupling between the scalar field and the Gauss-Bonnet invariant is quadratic in the scalar, whereas stable solutions exist for exponential couplings. Here, we elucidate this behavior. We demonstrate that, while the quadratic term controls the onset of the tachyonic instability that gives rise to the black hole hair, the higher-order coupling terms control the nonlinearities that quench that instability and, hence, also control the stability of the hairy black hole solutions.

Original languageEnglish (US)
Article number064011
JournalPhysical Review D
Volume99
Issue number6
DOIs
StatePublished - Mar 15 2019
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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