2018/12/31 by Hector O. Silva, Caio F. B. Macedo, Thomas P. Sotiriou +3 · 2 citations
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Black hole (networking) #Classical mechanics #Cosmology and Gravitation Theories #Einstein #Gauss–Bonnet gravity #Gauss–Bonnet theorem #General relativity #Geometry #Gravitation #Instability #Mathematical physics #Mathematics #Physics #Pulsars and Gravitational Waves Research #Quadratic equation #Quantum mechanics #Scalar (mathematics) #Scalar field #astro-ph.HE #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.99.064011
published as Phys. Rev. D 99, 064011 (2019) · 8 pages, 3 figures. Added citations, updated Fig.2, minor changes to the text. v3: Updated to match published version
openalex created_date 2018/12/22 · openalex publication_date 2019/03/12 · arxiv created 2019/03/26 · arxiv updated 2019/03/27 · openalex updated_date 2026/08/06
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.