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arXiv · 2502.14717

Purely metric Horndeski theories and spontaneous curvaturization of black holes

Astrid Eichhorn·Pedro G. S. Fernandes
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Abstract

We explore purely metric theories of gravity with second-order equations of motion and a single additional, purely gravitational, propagating, scalar degree of freedom. We identify a subclass of these theories in which this scalar causes a phenomenon similar to black-hole scalarization, which we call curvaturization: around small enough Kerr black holes, the scalar induces a tachyonic instability. This triggers a sudden growth of Ricci curvature and results in a new branch of vacuum black-hole solutions. We study the properties of these black holes both in the static as well as the spinning case.

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Astrid Eichhorn, Pedro G. S. Fernandes. 2025-02-20. Purely metric Horndeski theories and spontaneous curvaturization of black holes. https://doi.org/10.1103/physrevd.111.104007

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