Unstable chords and destructive resonant excitation of black hole quasinormal modes

Fuente: arXiv
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Main Authors: Oshita, Naritaka, Berti, Emanuele, Cardoso, Vitor
Format: Preprint
Published: 2025
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author Oshita, Naritaka
Berti, Emanuele
Cardoso, Vitor
author_facet Oshita, Naritaka
Berti, Emanuele
Cardoso, Vitor
contents The quasinormal mode spectrum of black holes is unstable against small modifications of the radial potential describing massless perturbations. We study how these small modifications affect the convergence of the quasinormal mode expansion and the mode excitation by computing the mode amplitudes from first principles, without relying on any fitting procedure. We show that the decomposition of the prompt ringdown waveform is not unique: small modifications in the radial potential produce new quasinormal mode ''basis sets'' that can improve the convergence of the quasinormal mode expansion, even capturing the late-time tail. We also study avoided crossings and exceptional points of the Kerr and Kerr-de Sitter spectrum. We show that while the mode amplitude can be resonantly excited, modes that exhibit avoided crossing destructively interfere with each other, so that the prompt ringdown waveform remains stable.
format Preprint
id arxiv_https___arxiv_org_abs_2503_21276
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unstable chords and destructive resonant excitation of black hole quasinormal modes
Oshita, Naritaka
Berti, Emanuele
Cardoso, Vitor
General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
The quasinormal mode spectrum of black holes is unstable against small modifications of the radial potential describing massless perturbations. We study how these small modifications affect the convergence of the quasinormal mode expansion and the mode excitation by computing the mode amplitudes from first principles, without relying on any fitting procedure. We show that the decomposition of the prompt ringdown waveform is not unique: small modifications in the radial potential produce new quasinormal mode ''basis sets'' that can improve the convergence of the quasinormal mode expansion, even capturing the late-time tail. We also study avoided crossings and exceptional points of the Kerr and Kerr-de Sitter spectrum. We show that while the mode amplitude can be resonantly excited, modes that exhibit avoided crossing destructively interfere with each other, so that the prompt ringdown waveform remains stable.
title Unstable chords and destructive resonant excitation of black hole quasinormal modes
topic General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
url https://arxiv.org/abs/2503.21276