Scalar perturbations around rotating regular black holes and wormholes: quasi-normal modes, ergoregion instability and superradiance

Abstract

We study scalar test-field perturbations on top of a Kerr--black-bounce background, i.e. a family of rotating regular black holes and/or rotating traversable wormholes that can mimic Kerr black holes. We compute the quasi-normal modes for a massless field in both the regular black holes and wormhole branches, confirming the stability of the former and identifying a set of growing modes that renders the latter unstable. We further compute the superradiance amplification factors, for massless and massive fields, in the regular black hole branch, confirming that these objects superradiate, though to a lesser degree than the corresponding Kerr black holes.

13 pages, 6 figures; v2 and v3: Added clarifications after review, published in PRD

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Cited by in corpus (12)

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• Probing hairy black holes caused by gravitational decoupling using quasinormal modes and greybody bounds
• Testing black hole mimickers with the Event Horizon Telescope image of Sagittarius A${}^{\ast }$
• Generalised Hayward spacetimes: Geometry, matter and scalar quasinormal modes
• Rotating traversable wormholes in Einstein-Maxwell theory
• Ringing and echoes from black bounces surrounded by the string cloud
• Regularising the JNW and JMN naked singularities
• Evaporation of a Kerr-black-bounce by emission of scalar particles
• Visions in Quantum Gravity
• Superradiance and quasinormal modes of the gravitational perturbation around rotating hairy black hole
• Scalar Perturbation Around Rotating Regular Black Hole: Superradiance Instability and Quasinormal Modes
• Arbitrary static, spherically symmetric space-times as solutions of scalar-tensor gravity