Ringdown and greybody signatures of rational regular black holes in non-polynomial gravity
Abstract
We study the quasinormal mode spectrum and wave-scattering properties of the four-dimensional rational regular black hole recently obtained in non-polynomial (quasi-topological) gravity. Using third-order WKB together with two independent cross-checks a Frobenius--Riccati shooting method and a time-domain evolution we compute the fundamental scalar, electromagnetic, and axial gravitational-type quasinormal frequencies, validating our approach against known Schwarzschild results. We find that as the geometry approaches extremality, its dimensionless ringing frequency is systematically suppressed relative to the Schwarzschild value, a direct and quantifiable imprint of the non-polynomial regularization that we trace, via the photon-sphere correspondence, to the response of the effective potential near the horizon. A Fisher-matrix estimate indicates that this suppression could in principle be resolved by a space-based detector such as LISA for a sufficiently massive and nearby source. We further compute, for the first time, the axial gravitational-type ringdown spectrum of this geometry using the Regge--Wheeler master equation, while noting that a full stability analysis of the underlying gravity theory remains an open problem requiring the linearized field equations of the modified action. Finally, we examine the greybody transmission factors across spins s=0,1,2 and show that they follow the same systematic ordering and near-extremal enhancement as the ringing-frequency suppression, pointing to a common physical origin. Together, these results give one of the first quantitative characterizations of the observational signatures and the remaining open theoretical questions of a regular black hole in modified gravity.
Related
- Rational regular black holes in non-polynomial gravity
- Understanding the high-resolution spectral signatures of Ar-D2O in the 3OD stretch region measured by cavity ringdown absorption spectroscopy
- Superintegrability of discrete-time rational Ruijsenaars-Schneider model and deformed polynomial symmetry algebras
- Beyond the polynomial ansatz: regular AdS3× M8 solutions of M-theory
- Signatures of charged rotating regular black holes: quasinormal modes, grey-body factors and shadows
BibTeX
@misc{jumaniyozov2026ringdown,
title = {{Ringdown and greybody signatures of rational regular black holes in non-polynomial gravity}},
author = {Shohzod Jumaniyozov and Javlon Rayimbaev and Azam Payzullaev and Bahodir Ahmedov and Ilkhomjon Makhmudov and Farhod Nuraliev},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.29062},
eprint = {2609.29062},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.29062},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Ringdown and greybody signatures of rational regular black holes in non-polynomial gravity
AU - Shohzod Jumaniyozov
AU - Javlon Rayimbaev
AU - Azam Payzullaev
AU - Bahodir Ahmedov
AU - Ilkhomjon Makhmudov
AU - Farhod Nuraliev
PY - 2026
DA - 2026/09/24
PB - arXiv
DO - 10.48550/arxiv.2609.29062
UR - https://arxiv.org/abs/2609.29062
AB - We study the quasinormal mode spectrum and wave-scattering properties of the four-dimensional rational regular black hole recently obtained in non-polynomial (quasi-topological) gravity. Using third-order WKB together with two independent cross-checks a Frobenius--Riccati shooting method and a time-domain evolution we compute the fundamental scalar, electromagnetic, and axial gravitational-type quasinormal frequencies, validating our approach against known Schwarzschild results. We find that as the geometry approaches extremality, its dimensionless ringing frequency is systematically suppressed relative to the Schwarzschild value, a direct and quantifiable imprint of the non-polynomial regularization that we trace, via the photon-sphere correspondence, to the response of the effective potential near the horizon. A Fisher-matrix estimate indicates that this suppression could in principle be resolved by a space-based detector such as LISA for a sufficiently massive and nearby source. We further compute, for the first time, the axial gravitational-type ringdown spectrum of this geometry using the Regge--Wheeler master equation, while noting that a full stability analysis of the underlying gravity theory remains an open problem requiring the linearized field equations of the modified action. Finally, we examine the greybody transmission factors across spins s=0,1,2 and show that they follow the same systematic ordering and near-extremal enhancement as the ringing-frequency suppression, pointing to a common physical origin. Together, these results give one of the first quantitative characterizations of the observational signatures and the remaining open theoretical questions of a regular black hole in modified gravity.
ER -