Transient dynamics of quasinormal mode sums

Fuente: arXiv
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Main Authors: Carballo, Javier, Withers, Benjamin
Format: Preprint
Published: 2024
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author Carballo, Javier
Withers, Benjamin
author_facet Carballo, Javier
Withers, Benjamin
contents Quasinormal modes of spacetimes with event horizons are typically governed by a non-normal operator. This gives rise to spectral instabilities, a topic of recent interest in the black hole pseudospectrum programme. In this work we show that non-normality leads to the existence of arbitrarily long-lived sums of short-lived quasinormal modes, corresponding to localising packets of energy near the future horizon. There exist sums of $M$ quasinormal modes whose lifetimes scale as $\log{M}$. This transient behaviour results from large cancellations between non-orthogonal quasinormal modes. We provide simple closed-form examples for a massive scalar field in the static patch of dS$_{d+1}$ and the BTZ black hole. We also provide numerical examples for scalar perturbations of Schwarzschild-AdS$_{d+1}$, and gravitational perturbations of Schwarzschild in asymptotically flat spacetime, using hyperboloidal foliations. The existence of these perturbations is linked to certain properties of black hole pseudospectra. We comment on implications for thermalisation times in holographic plasmas.
format Preprint
id arxiv_https___arxiv_org_abs_2406_06685
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Transient dynamics of quasinormal mode sums
Carballo, Javier
Withers, Benjamin
High Energy Physics - Theory
Strongly Correlated Electrons
General Relativity and Quantum Cosmology
Nuclear Theory
Quasinormal modes of spacetimes with event horizons are typically governed by a non-normal operator. This gives rise to spectral instabilities, a topic of recent interest in the black hole pseudospectrum programme. In this work we show that non-normality leads to the existence of arbitrarily long-lived sums of short-lived quasinormal modes, corresponding to localising packets of energy near the future horizon. There exist sums of $M$ quasinormal modes whose lifetimes scale as $\log{M}$. This transient behaviour results from large cancellations between non-orthogonal quasinormal modes. We provide simple closed-form examples for a massive scalar field in the static patch of dS$_{d+1}$ and the BTZ black hole. We also provide numerical examples for scalar perturbations of Schwarzschild-AdS$_{d+1}$, and gravitational perturbations of Schwarzschild in asymptotically flat spacetime, using hyperboloidal foliations. The existence of these perturbations is linked to certain properties of black hole pseudospectra. We comment on implications for thermalisation times in holographic plasmas.
title Transient dynamics of quasinormal mode sums
topic High Energy Physics - Theory
Strongly Correlated Electrons
General Relativity and Quantum Cosmology
Nuclear Theory
url https://arxiv.org/abs/2406.06685