Pith. sign in

REVIEW 2 major objections 2 minor 125 references

The quasinormal spectral gap in the RG-improved Schwarzschild black hole stays multipole-independent at the 6 percent level and keeps the geometry below the de Sitter bound for strong cosmic censorship.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

T0 review · grok-4.3

2026-07-01 09:11 UTC pith:VVSA2DAY

load-bearing objection Incremental scan of a phenomenological RG-improved Schwarzschild metric on shadows, QNMs, SCC ratio and thermodynamics; the lapse interpolation drives the main claims and is not derived from RG flow. the 2 major comments →

arxiv 2604.24798 v4 pith:VVSA2DAY submitted 2026-04-26 gr-qc hep-th

Renormalization-group improved Schwarzschild black hole: shadow, ringdown, and strong cosmic censorship

classification gr-qc hep-th
keywords black holesquasinormal modesstrong cosmic censorshiprenormalization groupshadow radiusringdownregular black holes
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper constructs a black-hole spacetime whose lapse function is altered by renormalization-group flow to remove the central singularity while preserving the asymptotic Schwarzschild form. It solves the wave equations for scalar, electromagnetic and Dirac perturbations, extracts the fundamental quasinormal frequencies and overtones with sixth-order WKB, and verifies the results in the time domain. The central result is that the ratio of the imaginary part of the frequency to the surface gravity at the inner horizon remains nearly constant across angular momenta, tracks the Lyapunov exponent of the photon sphere, and lies below the critical value required by the de Sitter version of strong cosmic censorship. The same geometry also produces a regular de Sitter core, a Davies-type thermodynamic transition at the outer horizon, and a shadow radius that differs from the classical value by only a few percent.

Core claim

For the RG-improved lapse controlled by cutoff scale ξ and interpolation parameter γ the resulting spacetime is regular, possesses an inner Cauchy horizon, and yields a quasinormal spectral gap β = |Im ω| / κ_- that is multipole-independent at the 6 percent level, satisfies β ≃ λ_L / (2 κ_-), stays below the Christodoulou bound, and belongs to the SCC-respecting class on the basis of its late-time power-law tail.

What carries the argument

The interpolation form of the lapse function between the classical Schwarzschild exterior and the quantum-smoothed de Sitter interior, parameterized by ξ and γ.

Load-bearing premise

The chosen interpolation between the classical exterior and the quantum interior is assumed to capture the dominant renormalization-group effects without further justification from a complete quantum-gravity calculation.

What would settle it

A calculation or observation that the ratio |Im ω| / κ_- rises above the Christodoulou bound or varies by more than a few percent with multipole number would falsify the central claim.

Watch this falsifier — get emailed when new claim-graph text bears on it.

If this is right

  • The outer-horizon temperature follows a bell-shaped curve rather than the classical 1/r decay and reaches a maximum near 0.062 in Planck units.
  • The static shadow radius remains degenerate with the Hayward and Bonanno-Reuter geometries at the percent level while the geometry is otherwise closest to classical Schwarzschild.
  • The Hawking flux sparsity and energy-emission rate are controlled by a single auxiliary function of the outer-horizon surface gravity.
  • The inner horizon is generated purely by the renormalization-group improvement, without electric charge or rotation.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If the same interpolation form appears in other quantum-gravity approaches, the multipole independence of β may be a generic feature of regular black holes with de Sitter cores.
  • The thermodynamic phase transition could be tested by comparing the specific heat of the outer horizon against future observations of black-hole thermodynamics in analogue systems.
  • The closeness of the shadow to the classical value suggests that current Event Horizon Telescope bounds on shadow size cannot yet distinguish this geometry from Schwarzschild.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

2 major / 2 minor

Summary. The manuscript studies a renormalization-group improved Schwarzschild black hole whose lapse interpolates between the classical exterior and a de Sitter core via two free parameters ξ and γ. It computes the photon sphere, shadow radius, and the Regge-Wheeler-Zerilli potentials for scalar, electromagnetic and Dirac fields; obtains fundamental and overtone quasinormal frequencies via sixth-order WKB cross-checked with time-domain integration; evaluates the spectral gap β = |Im ω|/κ_- at the inner horizon and its relation to the Lyapunov exponent; verifies that β remains below the de Sitter Christodoulou bound and that the late-time tail is consistent with SCC; performs a thermodynamic analysis revealing a Davies-type phase transition; and compares the model to Bardeen, Hayward and Bonanno-Reuter black holes at matched scales.

Significance. If the central numerical results hold, the work supplies a systematic parameter scan of an RG-motivated regular black hole, documenting its near-Schwarzschild shadow, the multipole-independence of β at the 6 % level, and its placement in the SCC-respecting class via both the spectral gap and the asymptotic tail. The explicit comparison with other regular black holes and the thermodynamic analysis constitute concrete additions to the literature on quantum-corrected spacetimes.

major comments (2)
  1. [§2 (metric ansatz and lapse function)] §2 (metric ansatz and lapse function): the interpolation form controlled by ξ and γ is introduced phenomenologically without derivation from an explicit beta-function flow or asymptotic-safety matching. Because both κ_- and the height of the Regge-Wheeler-Zerilli barrier are direct functions of this choice, the reported multipole-independence of β at the 6 % level, the relation β ≃ λ_L/(2 κ_-), and the conclusion that β lies below the Christodoulou bound are all internal to this two-parameter family; a different smoothing (e.g., exponential versus polynomial cutoff) can shift these quantities. This assumption is load-bearing for the SCC claim.
  2. [§4 (quasinormal-mode computation)] §4 (quasinormal-mode computation): the text provides no quantitative error bars on the WKB frequencies and no explicit convergence test for the sixth-order WKB approximation applied to the inner-horizon modes that determine β. Although a time-domain cross-check is mentioned, the convergence for the relevant overtones at the inner horizon should be demonstrated, e.g., by tabulating the change in Im ω when the WKB order is increased from 4 to 6.
minor comments (2)
  1. [Abstract and §6 (comparison section)] Abstract and §6 (comparison section): the statement that the improved Schwarzschild solution is “the most Schwarzschild-like” would be strengthened by a single quantitative figure of merit (e.g., integrated relative deviation of the metric function or of the shadow radius) rather than the percent-level degeneracy quoted for the shadow alone.
  2. [§5 (thermodynamics)] §5 (thermodynamics): the auxiliary function that relates the Hawking flux sparsity and energy-emission rate to the outer-horizon surface gravity is introduced without an explicit formula; adding the definition would improve reproducibility.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments. We address each major comment below.

read point-by-point responses
  1. Referee: [§2 (metric ansatz and lapse function)] §2 (metric ansatz and lapse function): the interpolation form controlled by ξ and γ is introduced phenomenologically without derivation from an explicit beta-function flow or asymptotic-safety matching. Because both κ_- and the height of the Regge-Wheeler-Zerilli barrier are direct functions of this choice, the reported multipole-independence of β at the 6 % level, the relation β ≃ λ_L/(2 κ_-), and the conclusion that β lies below the Christodoulou bound are all internal to this two-parameter family; a different smoothing (e.g., exponential versus polynomial cutoff) can shift these quantities. This assumption is load-bearing for the SCC claim.

    Authors: We agree that the lapse interpolation is introduced phenomenologically to realize an RG-improved geometry with a de Sitter core. This functional form is the standard choice in the RG-improved Schwarzschild literature, but it is not derived here from an explicit beta-function integration. Consequently the quantitative values of β, its multipole independence, and its position relative to the Christodoulou bound are specific to the present two-parameter family. We will revise §2 to state this limitation explicitly and to note that alternative smoothings could alter the numerical results, while preserving the scope of the paper as an analysis within this established ansatz. revision: partial

  2. Referee: [§4 (quasinormal-mode computation)] §4 (quasinormal-mode computation): the text provides no quantitative error bars on the WKB frequencies and no explicit convergence test for the sixth-order WKB approximation applied to the inner-horizon modes that determine β. Although a time-domain cross-check is mentioned, the convergence for the relevant overtones at the inner horizon should be demonstrated, e.g., by tabulating the change in Im ω when the WKB order is increased from 4 to 6.

    Authors: We accept the criticism. Although the time-domain integration was used as an independent check, we did not supply order-by-order WKB convergence data or error estimates for the inner-horizon overtones. We will add to §4 (and an accompanying table) the variation in Im ω between fourth- and sixth-order WKB for representative inner-horizon modes, together with the corresponding time-domain discrepancies, thereby providing the requested quantitative convergence test. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation is self-contained numerical evaluation within an explicit model

full rationale

The paper introduces an explicit two-parameter interpolation ansatz for the lapse function (controlled by ξ and γ) to define the metric, then computes horizon structure, Regge-Wheeler-Zerilli potentials, quasinormal modes via sixth-order WKB, and the spectral gap β directly from those quantities. The reported properties (multipole independence at the 6% level, approximate relation β ≃ λ_L/(2κ_-), and values below the Christodoulou bound) are numerical outputs evaluated across the parameter family, not identities forced by the definition of the inputs. No self-citations appear as load-bearing premises for the central SCC or ringdown claims, and the late-time tail classification follows from the computed asymptotics. The model is phenomenological by construction, but the derivation chain contains no self-definitional, fitted-prediction, or uniqueness reductions.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 1 invented entities

The central claims rest on two free parameters that define the metric, the assumption that the chosen interpolation captures RG effects, and standard GR background results; no machine-checked proofs or external benchmarks are supplied.

free parameters (2)
  • ξ
    Cutoff scale that sets the size of the quantum-smoothed interior region
  • γ
    Interpolation parameter controlling the transition between classical and quantum regimes
axioms (2)
  • domain assumption The exterior geometry remains exactly Schwarzschild for r larger than the cutoff region
    Stated in the abstract as the interpolation between classical exterior and quantum interior
  • ad hoc to paper The RG improvement produces a regular de Sitter core without additional curvature invariants or higher-derivative terms
    The specific lapse form is introduced to achieve regularity
invented entities (1)
  • de Sitter core no independent evidence
    purpose: Regularizes the central singularity
    Generated by the RG-improved lapse for ξ > 0, γ > 0

pith-pipeline@v0.9.1-grok · 5937 in / 1505 out tokens · 30717 ms · 2026-07-01T09:11:26.806289+00:00 · methodology

0 comments
read the original abstract

A renormalization-group (RG) improved Schwarzschild-like black hole (BH) is studied here, with a lapse that interpolates between a classical Schwarzschild exterior and a quantum-smoothed interior set by a cutoff scale $\xi$ and an interpolation parameter $\gamma$. We work out the horizon structure together with the photon sphere and shadow radius $R_{\mathrm{sh}}$, set up the scalar, electromagnetic, and Dirac Regge-Wheeler-Zerilli problems in a single treatment, and compute the fundamental and overtone quasinormal modes by sixth-order WKB, cross-checked against time-domain ringdown. For $\xi>0$ and $\gamma>0$ the geometry is regular, with a de Sitter core. Strong Cosmic Censorship (SCC) is examined at the inner Cauchy horizon, which the improved geometry generates without charge or rotation. The quasinormal spectral gap $\beta=|\mathrm{Im}\,\omega|/\kappa_-$ stays multipole-independent at the $6\%$ level and follows $\beta\simeq\lambda_{L}/(2\kappa_{-})$. It remains below the de Sitter Christodoulou bound across the parameter range, and the asymptotically flat late-time tail places the geometry in the SCC-respecting class. A thermodynamic analysis identifies a Davies-type phase transition of the outer horizon, with the Schwarzschild $T_{H}\propto 1/r_{+}$ decay replaced by a bell-curve profile peaking at $T_{H}^{\max}\simeq 0.062$. A scan of the $(\xi,\gamma)$ plane gathers the joint behavior of the shadow, the scalar barrier, the SCC ratio, and $T_H$. Set against Bardeen, Hayward, and Bonanno-Reuter BHs at matched perturbation scale, the improved Schwarzschild BH is the most Schwarzschild-like of the regular-BH family, its static shadow radius degenerate with Hayward and Bonanno-Reuter at the percent level. The closing analysis takes up the sparsity of the Hawking flux and the energy-emission rate, both tied to the outer-horizon surface gravity through a single auxiliary function.

Figures

Figures reproduced from arXiv: 2604.24798 by Ahmad Al-Badawi, Faizuddin Ahmed, \.Izzet Sakall{\i}.

Figure 1
Figure 1. Figure 1: FIG. 1 view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2 view at source ↗
Figure 3
Figure 3. Figure 3: shows Vscalar for ℓ = 2 across the two scans.The f ′/r term carries γ only through the γM combination inside the square-root structure of the lapse, and at the scalar peak r scalar peak ≃ rph − 0.05M – which sits at r scalar peak ≳ 3M – the ratio γM/r stays small. The ξ 2 corrections, by contrast, act at every radius and dominate the response, hence the wider spread on the right. The full two-dimensional (… view at source ↗
Figure 4
Figure 4. Figure 4: plots Vem across the same scans. The EM peak sits a little below the scalar peak at matched (ℓ, ξ, γ): at ℓ = 2, M = 1 the Schwarzschild scalar peak is V max scalar ≃ 0.247 against the EM peak V max em ≃ 0.187. Ordering under ξ and γ variation reproduces the scalar pattern, and this coherence across spin sectors confirms that the RG parameters act mostly as multiplicative modulators of the centrifugal barr… view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5 view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6 view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7 view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8 view at source ↗

discussion (0)

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Reference graph

Works this paper leans on

125 extracted references · 119 canonical work pages

  1. [1]

    author author S. Weinberg ,\ booktitle booktitle General Relativity: An Einstein Centenary Survey ,\ @noop journal journal General Relativity: An Einstein Centenary Survey \ ,\ pages 790 ( year 1979 ) NoStop

  2. [2]

    Reuter ,\ https://doi.org/10.1103/PhysRevD.57.971 journal journal Phys

    author author M. Reuter ,\ https://doi.org/10.1103/PhysRevD.57.971 journal journal Phys. Rev. D \ volume 57 ,\ pages 971 ( year 1998 ) NoStop

  3. [3]

    Niedermaier \ and\ author M

    author author M. Niedermaier \ and\ author M. Reuter ,\ https://doi.org/10.12942/lrr-2006-5 journal journal Living Rev. Rel. \ volume 9 ,\ pages 5 ( year 2006 ) NoStop

  4. [4]

    Bonanno \ and\ author M

    author author A. Bonanno \ and\ author M. Reuter ,\ https://doi.org/10.1103/PhysRevD.62.043008 journal journal Phys. Rev. D \ volume 62 ,\ pages 043008 ( year 2000 ) NoStop

  5. [5]

    Falls \ and\ author D

    author author K. Falls \ and\ author D. F. \ Litim ,\ https://doi.org/10.1103/PhysRevD.89.084002 journal journal Phys. Rev. D \ volume 89 ,\ pages 084002 ( year 2014 ) NoStop

  6. [6]

    Bonanno \ and\ author M

    author author A. Bonanno \ and\ author M. Reuter ,\ https://doi.org/10.1103/PhysRevD.73.083005 journal journal Phys. Rev. D \ volume 73 ,\ pages 083005 ( year 2006 ) NoStop

  7. [7]

    Koch \ and\ author F

    author author B. Koch \ and\ author F. Saueressig ,\ https://doi.org/10.1142/S0217751X14300117 journal journal Int. J. Mod. Phys. A \ volume 29 ,\ pages 1430011 ( year 2014 ) NoStop

  8. [8]

    Platania ,\ https://doi.org/10.1140/epjc/s10052-019-6990-2 journal journal Eur

    author author A. Platania ,\ https://doi.org/10.1140/epjc/s10052-019-6990-2 journal journal Eur. Phys. J. C \ volume 79 ,\ pages 470 ( year 2019 ) NoStop

  9. [9]

    Held , author R

    author author A. Held , author R. Gold , \ and\ author A. Eichhorn ,\ https://doi.org/10.1088/1475-7516/2019/06/029 journal journal JCAP \ volume 2019 ,\ pages 029 ( year 2019 ) NoStop

  10. [10]

    Eichhorn \ and\ author A

    author author A. Eichhorn \ and\ author A. Held ,\ https://doi.org/10.1140/epjc/s10052-021-09716-2 journal journal Eur. Phys. J. C \ volume 81 ,\ pages 933 ( year 2021 ) NoStop

  11. [11]

    First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole,

    author author K. Akiyamam and others (Event Horizon Telescope Collaboration) ,\ https://doi.org/10.3847/2041-8213/ab0ec7 journal journal Astrophys. J. Lett. \ volume 875 ,\ pages L1 ( year 2019 ) NoStop

  12. [12]

    Akiyamam and others (Event Horizon Telescope Collaboration) ,\ https://doi.org/10.3847/2041-8213/ac6674 journal journal Astrophys

    author author K. Akiyamam and others (Event Horizon Telescope Collaboration) ,\ https://doi.org/10.3847/2041-8213/ac6674 journal journal Astrophys. J. Lett. \ volume 930 ,\ pages L12 ( year 2022 ) NoStop

  13. [13]

    Quasinormal modes of black holes and black branes,

    author author E. Berti , author V. Cardoso , \ and\ author A. O. \ Starinets ,\ https://doi.org/10.1088/0264-9381/26/16/163001 journal journal Class. Quant. Grav. \ volume 26 ,\ pages 163001 ( year 2009 ) NoStop

  14. [14]

    author author R. A. \ Konoplya \ and\ author A. Zhidenko ,\ https://doi.org/10.1103/RevModPhys.83.793 journal journal Rev. Mod. Phys. \ volume 83 ,\ pages 793 ( year 2011 ) NoStop

  15. [15]

    \ Nollert ,\ https://doi.org/10.1088/0264-9381/16/12/201 journal journal Class

    author author H.-P. \ Nollert ,\ https://doi.org/10.1088/0264-9381/16/12/201 journal journal Class. Quant. Grav. \ volume 16 ,\ pages R159 ( year 1999 ) NoStop

  16. [16]

    Bonanno , author A

    author author A. Bonanno , author A. Khosravi , \ and\ author F. Saueressig ,\ https://doi.org/10.1103/PhysRevD.107.024005 journal journal Phys. Rev. D \ volume 107 ,\ pages 024005 ( year 2023 ) NoStop

  17. [17]

    author author S. W. \ Hawking ,\ https://doi.org/10.1007/BF02345020 journal journal Commun. Math. Phys. \ volume 43 ,\ pages 199 ( year 1975 ) NoStop

  18. [18]

    author author J. D. \ Bekenstein ,\ https://doi.org/10.1103/PhysRevD.7.2333 journal journal Phys. Rev. D \ volume 7 ,\ pages 2333 ( year 1973 ) NoStop

  19. [19]

    author author J. M. \ Bardeen , author B. Carter , \ and\ author S. W. \ Hawking ,\ https://doi.org/10.1007/BF01645742 journal journal Commun. Math. Phys. \ volume 31 ,\ pages 161 ( year 1973 ) NoStop

  20. [20]

    Battista ,\ 10.1103/PhysRevD.109.026004 journal journal Phys

    author author E. Battista ,\ 10.1103/PhysRevD.109.026004 journal journal Phys. Rev. D \ volume 109 ,\ pages 026004 ( year 2024 ) NoStop

  21. [21]

    \ Wang \ and\ author E

    author author Z.-L. \ Wang \ and\ author E. Battista ,\ 10.1140/epjc/s10052-025-13833-7 journal journal Eur. Phys. J. C \ volume 85 ,\ pages 304 ( year 2025 ) NoStop

  22. [22]

    author author R. A. \ Konoplya , author D. Ovchinnikov , \ and\ author B. Ahmedov ,\ 10.1103/PhysRevD.108.104054 journal journal Phys. Rev. D \ volume 108 ,\ pages 104054 ( year 2023 ) NoStop

  23. [23]

    author author A. M. \ Bonanno , author R. A. \ Konoplya , author G. Oglialoro , \ and\ author A. Spina ,\ 10.1088/1475-7516/2025/12/042 journal journal JCAP \ volume 2025 ,\ pages 042 ( year 2025 ) NoStop

  24. [24]

    Sucu , author I

    author author E. Sucu , author I. Sakalli , \ and\ author Y. Sucu ,\ 10.1142/S0219887826501161 journal journal Int. J Geom. Meth. Mod. Phys. \ ( year 2026 ),\ 10.1142/S0219887826501161 ,\ note online NoStop

  25. [25]

    Sucu \ and\ author I

    author author E. Sucu \ and\ author I. Sakalli ,\ 10.1140/epjc/s10052-025-14726-5 journal journal Eur. Phys. J. C \ volume 85 ,\ pages 989 ( year 2025 ) NoStop

  26. [26]

    Aydiner , author E

    author author E. Aydiner , author E. Sucu , \ and\ author I. Sakalli ,\ 10.1016/j.dark.2025.102164 journal journal Phys. Dark Univ. \ volume 50 ,\ pages 102164 ( year 2025 ) NoStop

  27. [27]

    Ahmed , author A

    author author F. Ahmed , author A. Al-Badawi , \ and\ author I. Sakalli ,\ 10.1016/j.dark.2025.101988 journal journal Phys. Dark Univ. \ volume 49 ,\ pages 101988 ( year 2025 a ) NoStop

  28. [28]

    Ahmed , author A

    author author F. Ahmed , author A. Al-Badawi , \ and\ author I. Sakalli ,\ 10.1142/S0219887825502573 journal journal Int. J Geom. Meth. Mod. Phys. \ ( year 2025 b ),\ 10.1142/S0219887825502573 ,\ note online NoStop

  29. [29]

    Sucu \ and\ author \

    author author E. Sucu \ and\ author \. I . Sakall ,\ 10.1098/rspa.2025.0251 journal journal Proc. R. Soc. A \ volume 481 ,\ pages 20250251 ( year 2025 a ) NoStop

  30. [30]

    Sucu \ and\ author \

    author author E. Sucu \ and\ author \. I . Sakall ,\ 10.1088/1674-1137/add8fe journal journal Chin. Phys. C \ volume 49 ,\ pages 105101 ( year 2025 b ) NoStop

  31. [31]

    Ahmed , author A

    author author F. Ahmed , author A. Al-Badawi , \ and\ author \. I . Sakall ,\ 10.1140/epjc/s10052-025-14266-y journal journal Eur. Phys. J C \ volume 85 ,\ pages 545 ( year 2025 c ) NoStop

  32. [32]

    Mangut , author H

    author author M. Mangut , author H. Gursel , \ and\ author I. Sakalli ,\ 10.1088/1674-1137/adbacf journal journal Chin. Phys. C \ volume 49 ,\ pages 065106 ( year 2025 ) NoStop

  33. [33]

    Pourhassan , author X

    author author B. Pourhassan , author X. Shi , author S. S. \ Wani , author S. Al-Kuwari , author I. Sakalli , author N. A. \ Shah , author M. Faizal , \ and\ author A. Shabir ,\ 10.1016/j.aop.2025.169983 journal journal Ann. Phys. \ volume 477 ,\ pages 169983 ( year 2025 ) NoStop

  34. [34]

    author author S. N. \ Gashti , author B. Pourhassan , \ and\ author \. I . Sakall ,\ 10.3390/universe11080247 journal journal Universe \ volume 11 ,\ pages 247 ( year 2025 ) NoStop

  35. [35]

    Cardoso , author J

    author author V. Cardoso , author J. L. \ Costa , author K. Destounis , author P. Hintz , \ and\ author A. Jansen ,\ https://doi.org/10.1103/PhysRevLett.120.031103 journal journal Phys. Rev. Lett. \ volume 120 ,\ pages 031103 ( year 2018 ) NoStop

  36. [36]

    author author O. J. C. \ Dias , author H. S. \ Reall , \ and\ author J. E. \ Santos ,\ 10.1007/JHEP10(2018)001 journal journal JHEP \ volume 2018 ,\ pages 001 ( year 2018 ) NoStop

  37. [37]

    \ Cao , author L.-Y

    author author L.-M. \ Cao , author L.-Y. \ Li , author X.-Y. \ Liu , \ and\ author Y.-S. \ Zhou ,\ 10.1103/PhysRevD.109.084021 journal journal Phys. Rev. D \ volume 109 ,\ pages 084021 ( year 2024 ) NoStop

  38. [38]

    Hod ,\ 10.1016/j.nuclphysb.2019.03.003 journal journal Nucl

    author author S. Hod ,\ 10.1016/j.nuclphysb.2019.03.003 journal journal Nucl. Phys. B \ volume 941 ,\ pages 636 ( year 2019 ) NoStop

  39. [40]

    Casals \ and\ author C

    author author M. Casals \ and\ author C. I. S. \ Marinho ,\ 10.1103/PhysRevD.106.044060 journal journal Phys. Rev. D \ volume 106 ,\ pages 044060 ( year 2022 ) NoStop

  40. [41]

    Alencar , author T

    author author G. Alencar , author T. M. \ Crispim , author C. R. \ Muniz , \ and\ author M. Nilton ,\ https://arxiv.org/abs/2603.05130 ( year 2026 ),\ http://arxiv.org/abs/2603.05130 arXiv:2603.05130 [gr-qc] NoStop

  41. [42]

    Cardoso , author A

    author author V. Cardoso , author A. S. \ Miranda , author E. Berti , author H. Witek , \ and\ author V. T. \ Zanchin ,\ 10.1103/PhysRevD.79.064016 journal journal Phys. Rev. D \ volume 79 ,\ pages 064016 ( year 2009 ) NoStop

  42. [43]

    author author I. Z. \ Stefanov , author S. S. \ Yazadjiev , \ and\ author G. G. \ Gyulchev ,\ 10.1103/PhysRevLett.104.251103 journal journal Phys. Rev. Lett. \ volume 104 ,\ pages 251103 ( year 2010 ) NoStop

  43. [44]

    \ Chen , author H

    author author C.-Y. \ Chen , author H. W. \ Chiang , \ and\ author J.-S. \ Tsao ,\ 10.1103/PhysRevD.106.044068 journal journal Phys. Rev. D \ volume 106 ,\ pages 044068 ( year 2022 ) NoStop

  44. [45]

    Meng , author X.-M

    author author Y. Meng , author X.-M. \ Kuang , \ and\ author Z.-Y. \ Tang ,\ 10.1103/PhysRevD.106.064006 journal journal Phys. Rev. D \ volume 106 ,\ pages 064006 ( year 2022 ) NoStop

  45. [46]

    Miguel Ladino \ and\ author E

    author author J. Miguel Ladino \ and\ author E. Larranaga ,\ 10.1007/s10773-023-05440-7 journal journal Int. J. Theor. Phys. \ volume 62 ,\ pages 209 ( year 2023 ) NoStop

  46. [47]

    Yu \ and\ author C

    author author S. Yu \ and\ author C. Gao ,\ 10.1142/S0217732320502569 journal journal Mod. Phys. Lett. A \ volume 35 ,\ pages 2050256 ( year 2020 ) NoStop

  47. [48]

    Ovgun , author I

    author author A. Ovgun , author I. Sakalli , \ and\ author J. Saavedra ,\ 10.1088/1674-1137/42/10/105102 journal journal Chin. Phys. C \ volume 42 ,\ pages 105102 ( year 2018 ) NoStop

  48. [49]

    Murodov , author J

    author author S. Murodov , author J. Rayimbaev , author B. Ahmedov , \ and\ author E. Karimbaev ,\ 10.3390/universe9090391 journal journal Universe \ volume 9 ,\ pages 391 ( year 2023 ) NoStop

  49. [50]

    author author J. L. \ Synge ,\ https://doi.org/10.1093/mnras/131.3.463 journal journal Mon. Not. Roy. Astron. Soc. \ volume 131 ,\ pages 463 ( year 1966 ) NoStop

  50. [51]

    \ Luminet ,\ @noop journal journal Astronomy and Astrophysics \ volume 75 ,\ pages 228 ( year 1979 ) NoStop

    author author J.-P. \ Luminet ,\ @noop journal journal Astronomy and Astrophysics \ volume 75 ,\ pages 228 ( year 1979 ) NoStop

  51. [52]

    author author J. M. \ Bardeen ,\ @noop journal journal Les Houches Summer School of Theoretical Physics: Black Holes \ ,\ pages 215 ( year 1973 ) NoStop

  52. [53]

    author author P. V. P. \ Cunha \ and\ author C. A. R. \ Herdeiro ,\ https://doi.org/10.1007/s10714-018-2361-9 journal journal Gen. Rel. Grav. \ volume 50 ,\ pages 42 ( year 2018 ) NoStop

  53. [54]

    Perlick \ and\ author O

    author author V. Perlick \ and\ author O. Y. \ Tsupko ,\ https://doi.org/10.1016/j.physrep.2021.10.004 journal journal Phys. Rept. \ volume 947 ,\ pages 1 ( year 2022 ) NoStop

  54. [55]

    Chandrasekhar ,\ @noop title The Mathematical Theory of Black Holes \ ( publisher Oxford University Press ,\ address Oxford ,\ year 1998 ) NoStop

    author author S. Chandrasekhar ,\ @noop title The Mathematical Theory of Black Holes \ ( publisher Oxford University Press ,\ address Oxford ,\ year 1998 ) NoStop

  55. [56]

    author author C. V. \ Vishveshwara ,\ https://doi.org/10.1038/227936a0 journal journal Nature \ volume 227 ,\ pages 936 ( year 1970 ) NoStop

  56. [57]

    author author K. D. \ Kokkotas \ and\ author B. G. \ Schmidt ,\ https://doi.org/10.12942/lrr-1999-2 journal journal Living Rev. Rel. \ volume 2 ,\ pages 2 ( year 1999 ) NoStop

  57. [58]

    author author C. Y. \ Zhang , author Z. Y. \ Tang , \ and\ author B. Wang ,\ https://doi.org/10.1103/PhysRevD.94.104013 journal journal Phys. Rev. D \ volume 94 ,\ pages 104013 ( year 2016 ) NoStop

  58. [59]

    Stability of a Schwarzschild singularity,

    author author T. Regge \ and\ author J. A. \ Wheeler ,\ https://doi.org/10.1103/PhysRev.108.1063 journal journal Phys. Rev. \ volume 108 ,\ pages 1063 ( year 1957 ) NoStop

  59. [60]

    author author F. J. \ Zerilli ,\ https://doi.org/10.1103/PhysRevLett.24.737 journal journal Phys. Rev. Lett. \ volume 24 ,\ pages 737 ( year 1970 ) NoStop

  60. [61]

    author author L. C. B. \ Crispino , author A. Higuchi , \ and\ author G. E. A. \ Matsas ,\ https://doi.org/10.1088/0264-9381/17/1/303 journal journal Class. Quant. Grav. \ volume 17 ,\ pages 19 ( year 2000 ) NoStop

  61. [62]

    Ruffini \ and\ author J

    author author R. Ruffini \ and\ author J. A. \ Wheeler ,\ https://doi.org/10.1063/1.3022513 journal journal Phys. Today \ volume 24 ,\ pages 30 ( year 1971 ) NoStop

  62. [63]

    Unruh ,\ https://doi.org/10.1103/PhysRevLett.31.1265 journal journal Phys

    author author W. Unruh ,\ https://doi.org/10.1103/PhysRevLett.31.1265 journal journal Phys. Rev. Lett. \ volume 31 ,\ pages 1265 ( year 1973 ) NoStop

  63. [64]

    Chandrasekhar ,\ https://doi.org/10.1098/rspa.1976.0090 journal journal Proc

    author author S. Chandrasekhar ,\ https://doi.org/10.1098/rspa.1976.0090 journal journal Proc. Roy. Soc. Lond. A \ volume 349 ,\ pages 571 ( year 1976 ) NoStop

  64. [65]

    author author LIGO Scientific, Virgo and KAGRA Collaborations ,\ https://doi.org/10.1103/PhysRevD.103.122002 journal journal Phys. Rev. D \ volume 103 ,\ pages 122002 ( year 2021 ) NoStop

  65. [66]

    Cardoso \ and\ author L

    author author V. Cardoso \ and\ author L. Gualtieri ,\ https://doi.org/10.1088/0264-9381/33/17/174001 journal journal Class. Quant. Grav. \ volume 33 ,\ pages 174001 ( year 2016 ) NoStop

  66. [67]

    author author LIGO Scientific and Virgo Collaborations ,\ https://doi.org/10.1103/PhysRevLett.116.061102 journal journal Phys. Rev. Lett. \ volume 116 ,\ pages 061102 ( year 2016 ) NoStop

  67. [68]

    author author B. F. \ Schutz \ and\ author C. M. \ Will ,\ https://doi.org/10.1086/184453 journal journal Astrophys. J. Lett. \ volume 291 ,\ pages L33 ( year 1985 ) NoStop

  68. [69]

    Black-hole normal modes: A WKB approach. I. Foundations and application of a higher-order WKB analysis of potential-barrier scattering,

    author author S. Iyer \ and\ author C. M. \ Will ,\ https://doi.org/10.1103/PhysRevD.35.3621 journal journal Phys. Rev. D \ volume 35 ,\ pages 3621 ( year 1987 ) NoStop

  69. [70]

    Iyer ,\ https://doi.org/10.1103/PhysRevD.35.3632 journal journal Phys

    author author S. Iyer ,\ https://doi.org/10.1103/PhysRevD.35.3632 journal journal Phys. Rev. D \ volume 35 ,\ pages 3632 ( year 1987 ) NoStop

  70. [71]

    author author K. D. \ Kokkotas \ and\ author B. F. \ Schutz ,\ https://doi.org/10.1103/PhysRevD.37.3378 journal journal Phys. Rev. D \ volume 37 ,\ pages 3378 ( year 1988 ) NoStop

  71. [72]

    author author R. A. \ Konoplya ,\ https://doi.org/10.1103/PhysRevD.68.024018 journal journal Phys. Rev. D \ volume 68 ,\ pages 024018 ( year 2003 ) NoStop

  72. [73]

    author author R. A. \ Konoplya , author A. Zhidenko , \ and\ author A. F. \ Zinhailo ,\ https://doi.org/10.1088/1361-6382/ab2e25 journal journal Class. Quant. Grav. \ volume 36 ,\ pages 155002 ( year 2019 ) NoStop

  73. [74]

    Matyjasek \ and\ author M

    author author J. Matyjasek \ and\ author M. Opala ,\ https://doi.org/10.1103/PhysRevD.96.024011 journal journal Phys. Rev. D \ volume 96 ,\ pages 024011 ( year 2017 ) NoStop

  74. [75]

    Hatsuda ,\ https://doi.org/10.1103/PhysRevD.101.024008 journal journal Phys

    author author Y. Hatsuda ,\ https://doi.org/10.1103/PhysRevD.101.024008 journal journal Phys. Rev. D \ volume 101 ,\ pages 024008 ( year 2020 ) NoStop

  75. [76]

    Ahmed , author A

    author author F. Ahmed , author A. Al-Badawi , author I. Sakalli , \ and\ author A. Bouzenada ,\ 10.1016/j.nuclphysb.2025.116806 journal journal Nucl. Phys. B \ volume 1011 ,\ pages 116806 ( year 2025 d ) NoStop

  76. [77]

    Jusufi ,\ 10.1103/PhysRevD.101.084055 journal journal Phys

    author author K. Jusufi ,\ 10.1103/PhysRevD.101.084055 journal journal Phys. Rev. D \ volume 101 ,\ pages 084055 ( year 2020 ) NoStop

  77. [78]

    author author R. A. \ Konoplya \ and\ author A. Zhidenko ,\ https://doi.org/10.1088/1475-7516/2019/09/068 journal journal JCAP \ volume 2019 ,\ pages 068 ( year 2019 ) NoStop

  78. [79]

    author author E. W. \ Leaver ,\ https://doi.org/10.1098/rspa.1985.0119 journal journal Proc. Roy. Soc. Lond. A \ volume 402 ,\ pages 285 ( year 1985 ) NoStop

  79. [80]

    Gundlach , author R

    author author C. Gundlach , author R. H. \ Price , \ and\ author J. Pullin ,\ https://doi.org/10.1103/PhysRevD.49.883 journal journal Phys. Rev. D \ volume 49 ,\ pages 883 ( year 1994 a ) NoStop

  80. [81]

    Gundlach , author R

    author author C. Gundlach , author R. H. \ Price , \ and\ author J. Pullin ,\ https://doi.org/10.1103/PhysRevD.49.890 journal journal Phys. Rev. D \ volume 49 ,\ pages 890 ( year 1994 b ) NoStop

Showing first 80 references.