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BRIEF RESEARCH REPORT article

Front. Phys.
Sec. Cosmology
Volume 12 - 2024 | doi: 10.3389/fphy.2024.1511757
This article is part of the Research Topic Quasi-Normal Modes, Non-Selfadjoint Operators and Pseudospectrum: an Interdisciplinary Approach View all 11 articles

On destabilising quasi-normal modes with a radially concentrated perturbation

Provisionally accepted
Valentin Boyanov Valentin Boyanov *
  • Associação do Instituto Superior Técnico de Investigação e Desenvolvimento (IST-ID), Lisboa, Portugal

The final, formatted version of the article will be published soon.

    In this work we explore some aspects of the spectral instability of back hole quasi-normal modes, using a specific model as an example. The model is that of a small bump perturbation to the effective potential of linear axial gravitational waves on a Schwarzschild background, and our focus is on three different aspects of the instability: identifying and distinguishing between the two different types of instabilities studied previously in the literature, quantifying the size of the perturbations applied to the system and testing the validity of the pseudospectral numerical method in providing a convergent result for this measure, and finally, relating the size and other features of the perturbation to the degree of destabilisation of the spectrum.

    Keywords: black hole, Quasinormal modes, Pseudospectrum, Energy norm, Spectral stability

    Received: 15 Oct 2024; Accepted: 10 Dec 2024.

    Copyright: © 2024 Boyanov. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Valentin Boyanov, Associação do Instituto Superior Técnico de Investigação e Desenvolvimento (IST-ID), Lisboa, Portugal

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