Stability and quasinormal modes for black holes with time-dependent scalar hair

Fuente: arXiv
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Main Authors: Sirera, Sergi, Noller, Johannes
Format: Preprint
Published: 2024
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author Sirera, Sergi
Noller, Johannes
author_facet Sirera, Sergi
Noller, Johannes
contents We investigate black hole solutions with time-dependent (scalar) hair in scalar-tensor theories. Known exact solutions exist for such theories at the background level, where the metric takes on a standard GR form (e.g. Schwarzschild-de Sitter), but these solutions are generically plagued by instabilities. Recently, a new such solution was identified in arXiv:2310.11919, in which the time-dependent scalar background profile is qualitatively different from previous known exact solutions - specifically, the canonical kinetic term for the background scalar $X$ is not constant in this solution. We investigate the stability of this new solution by analysing odd parity perturbations, identifying a bound placed by stability and the resulting surviving parameter space. We extract the quasinormal mode spectrum predicted by the theory, identifying a shift of quasinormal mode frequencies and damping times compared to GR. We forecast constraints on these shifts (and the single effective parameter $\hatβ$ controlling them) from current and future gravitational wave experiments, finding constraints at up to the ${\cal O}(10^{-2})$ and ${\cal O}(10^{-6})$ level for LVK and LISA/TianQin, respectively. All calculations performed in this paper are reproducible via a companion Mathematica notebook.
format Preprint
id arxiv_https___arxiv_org_abs_2408_01720
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Stability and quasinormal modes for black holes with time-dependent scalar hair
Sirera, Sergi
Noller, Johannes
General Relativity and Quantum Cosmology
We investigate black hole solutions with time-dependent (scalar) hair in scalar-tensor theories. Known exact solutions exist for such theories at the background level, where the metric takes on a standard GR form (e.g. Schwarzschild-de Sitter), but these solutions are generically plagued by instabilities. Recently, a new such solution was identified in arXiv:2310.11919, in which the time-dependent scalar background profile is qualitatively different from previous known exact solutions - specifically, the canonical kinetic term for the background scalar $X$ is not constant in this solution. We investigate the stability of this new solution by analysing odd parity perturbations, identifying a bound placed by stability and the resulting surviving parameter space. We extract the quasinormal mode spectrum predicted by the theory, identifying a shift of quasinormal mode frequencies and damping times compared to GR. We forecast constraints on these shifts (and the single effective parameter $\hatβ$ controlling them) from current and future gravitational wave experiments, finding constraints at up to the ${\cal O}(10^{-2})$ and ${\cal O}(10^{-6})$ level for LVK and LISA/TianQin, respectively. All calculations performed in this paper are reproducible via a companion Mathematica notebook.
title Stability and quasinormal modes for black holes with time-dependent scalar hair
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2408.01720