We consider a scalar field propagating in the static region of the two dimensional de Sitter space. This simple system is used to illustrate the advantages of hyperboloidal foliations in the analysis of quasinormal modes.
We study the quasinormal mode eigenvalues and eigenfunctions for the Teukolsky equation in a horizon penetrating, hyperboloidally compactified (HPHC) coordinate system. Following earlier work by Zenginoğlu (arXiv:1102.2451), we show that the quasinormal eigenfunctions for the Teukolsky equation are regular from the black hole horizon to future null infinity in these coordinates. We then present several example quasinormal eigenfunction solutions, and study some of their properties in the near-extremal Kerr limit.
Charged Scalar Field at Future Null Infinity via Nonlinear Hyperboloidal Evolution
CENTRA, Departamento de Física do Instituto Superior Técnico (IST), Universidade de Lisboa(里斯本大学高级理论研究中心物理系技术研究所);Instituto de Telecomunicações (IT), Universidade de Aveiro(阿威罗大学电信研究所);Departament de Física, Universitat de les Illes Balears(巴利阿里群岛大学物理系)
Kerr Quasinormal Modes without Variable Separation: A Two-Dimensional Hyperboloidal Teukolsky Solver with Physics-Informed Neural Networks
University of Valencia(瓦伦西亚大学);Eberhard Karls University of Tübingen(蒂宾根大学);Sofia University(索非亚大学);Bulgarian Academy of Sciences(保加利亚科学院);Instituto de Física Corpuscular CSIC-UV(CSIC-UV 粒子物理研究所)
The idea that quantum gravity effects might leak outside the horizon of a black hole has recently been intensively considered. In this study, we calculate the quasinormal modes as a function of the location and amplitude of a generic metric perturbation distorting to the Schwarzschild spacetime. We conclude on the possible observability of quantum metric corrections by current and future gravitational wave experiments.
The quasinormal modes of the rotating quantum corrected black holes
School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, UCAS(杭州高等研究院基础物理与数学学院);Institute of Theoretical Physics, Chinese Academy of Sciences(中国科学院理论物理研究所);University of Chinese Academy of Sciences(中国科学院大学)
Physics-informed neural networks (PINNs) hold the potential for supplementing the existing set of techniques for solving differential equations that emerge in the study of black hole quasinormal modes. The present research investigated them by studying black hole perturbation equations with known analytical solutions and thus could be framed as inverse problems in PINNs. Our main goal was to test the accuracy of PINNs in computing unknown quasinormal frequencies within the differential equations. The black hole perturbation scenarios that we considered included near extremal Schwarzschild-de S…
Black hole spectroscopy is a powerful tool to probe the Kerr nature of astrophysical compact objects and their environment. The observation of multiple ringdown modes in gravitational waveforms could soon lead to high-precision gravitational spectroscopy, so it is critical to understand if the quasinormal mode spectrum is stable against perturbations. It was recently shown that the pseudospectrum can shed light on the spectral stability of black hole quasinormal modes. We study the pseudospectrum of Reissner-Nordström spacetimes and we find a spectral instability of scalar and gravitoelectric …
We study the stability of quasinormal modes (QNM) in asymptotically flat black hole spacetimes by means of a pseudospectrum analysis. The construction of the Schwarzschild QNM pseudospectrum reveals the following: (i) the stability of the slowest-decaying QNM under perturbations respecting the asymptotic structure, reassessing the instability of the fundamental QNM discussed by Nollert [H. P. Nollert, About the Significance of Quasinormal Modes of Black Holes, Phys. Rev. D 53, 4397 (1996)] as an "infrared" effect; (ii) the instability of all overtones under small-scale ("ultraviolet") perturba…
Niels Bohr Institute(尼尔斯·玻尔研究所);CENTRA, Departamento de Fisica, Instituto Superior Técnico – IST, Universidade de Lisboa – UL(科英布拉天体物理与中心研究中心,物理学系,高等技术学院,里斯本大学);University of Birmingham(伯明翰大学);University of Nottingham(诺丁汉大学)
Recent work applying the notion of pseudospectrum to gravitational physics showed that the quasinormal mode spectrum of black holes is unstable, with the possible exception of the longest-lived (fundamental) mode. The fundamental mode dominates the expected signal in gravitational wave astronomy, and there is no reason why it should have privileged status. We compute the quasinormal mode spectrum of two model problems where the Schwarzschild potential is perturbed by a small "bump" consisting of either a Pöschl-Teller potential or a Gaussian, and we show that the fundamental mode is destabiliz…
Nonlinear tails of massive scalar fields around a black hole
University of Chinese Academy of Sciences(中国科学院大学);International Centre for Theoretical Physics Asia-Pacific (ICTP-AP)(亚太理论物理中心);Taiji Laboratory for Gravitational Wave Universe(太极引力波宇宙实验室)
Scalar perturbations around the Kerr black hole in scalar-Einstein-Gauss-Bonnet (sEGB) theory are studied in the time domain. To overcome the "outer boundary problem" that usually encountered in traditional numerical calculations, we apply the hyperboloidal compactification technique to perform a $(2+1)$-dimensional simulation aiming to obtain a precise object picture of the wave propagation under the scalar field perturbation. We find that the big enough coupling constant between the scalar field and the Gauss-Bonnet curvature is responsible to destroy the original Kerr black hole. The breakd…