pith. sign in

arxiv: 2502.11209 · v3 · submitted 2025-02-16 · 🌀 gr-qc

Black-hole spectroscopy from a giant quantum vortex

Pietro Smaniotto , Leonardo Solidoro , Patrik \v{S}van\v{c}ara , Sam Patrick , Maur\'icio Richartz , Carlo F. Barenghi , Ruth Gregory , Silke Weinfurtner This is my paper

Pith reviewed 2026-05-23 02:47 UTC · model grok-4.3

classification 🌀 gr-qc
keywords black hole spectroscopyquasinormal modesquantum vortexsuperfluid heliumanalogue gravityrotating black holeKerr geometry
0
0 comments X

The pith

Multiple quasinormal modes of a rotating black hole are extracted from noise-driven waves around a giant quantum vortex in superfluid helium-4.

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

The paper shows that waves at the free surface of a large quantum vortex in superfluid helium can be decomposed into distinct azimuthal modes whose frequencies and damping match the quasinormal-mode spectrum expected for a Kerr black hole. In real astrophysical signals the higher overtones decay too fast to be measured except in the loudest events, but the finite laboratory system reduces damping and shifts the real frequencies in a way that makes the full spectrum accessible. The authors resolve both the longest-lived fundamental modes and their higher-frequency overtones directly from the noise-driven motion, demonstrating that the laboratory analog reproduces the black-hole ringdown structure. This establishes a concrete experimental route to black-hole spectroscopy that complements numerical simulations and gravitational-wave observations.

Core claim

Multiple QNMs can be extracted from noise-driven interface waves surrounding a giant quantum vortex in superfluid helium-4, which emulates a spacetime geometry indicative of a rotating black hole. By resolving waves with different azimuthal periodicity, both fundamental modes and their higher-frequency overtones are excited and oscillate at frequencies given by the size of the system.

What carries the argument

Giant quantum vortex in superfluid helium-4 whose interface waves emulate the quasinormal-mode spectrum of a Kerr black hole, with azimuthal mode numbers mapping to black-hole angular momentum.

If this is right

  • In finite-sized systems the real frequencies of QNMs shift while their damping rates reduce, thereby enhancing their detectability compared with unbounded settings.
  • Both fundamental modes and higher-frequency overtones are excited and can be separated by resolving different azimuthal periodicities.
  • Gravity simulators can now complement numerical and observational approaches to black-hole spectroscopy.
  • Similar finite-size or environmental effects on the QNM spectrum may arise in astrophysical scenarios due to the interstellar medium or dark matter.

Where Pith is reading between the lines

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

  • Varying the vortex radius or rotation rate in future runs could map how the entire QNM spectrum depends on system size, testing the finite-size corrections predicted by the analogy.
  • The same interface-wave technique might be adapted to other analogue spacetimes to study environmental modifications to ringdown that are difficult to model in full general relativity.
  • If the damping reduction scales with system size, larger quantum vortices could make even higher overtones measurable, providing a laboratory test bed for the information carried by sub-dominant modes.

Load-bearing premise

The fluid-interface waves in the finite-sized quantum vortex reproduce the quasinormal-mode spectrum including damping rates of a Kerr black hole in general relativity.

What would settle it

Measured oscillation frequencies or damping rates of the resolved azimuthal waves that deviate systematically from the Kerr quasinormal-mode predictions for the equivalent mass and spin would falsify the mapping.

Figures

Figures reproduced from arXiv: 2502.11209 by Carlo F. Barenghi, Leonardo Solidoro, Maur\'icio Richartz, Patrik \v{S}van\v{c}ara, Pietro Smaniotto, Ruth Gregory, Sam Patrick, Silke Weinfurtner.

Figure 1
Figure 1. Figure 1: a outlines the geometry of our experiment. The giant quantum vortex is located above the central open￾ing (black region) and manifests itself as a distinct, ap￾proximately 15 mm deep and 5 mm wide depression of the superfluid interface. Interface height fluctuations are resolved within an 21.8-mm wide annular region (orange) that is surrounded by an outer boundary (grey). Cylin￾drical symmetry and stationa… view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2 [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3 [PITH_FULL_IMAGE:figures/full_fig_p010_3.png] view at source ↗
read the original abstract

Black-hole spectroscopy aims to infer the fundamental properties of black holes by analysing the spectrum of gravitational waves emitted as they settle into equilibrium. These resonances, known as quasinormal modes (QNMs), decay rapidly, which limits the time-domain analysis of gravitational-wave data or numerical simulations to the longest-lived mode, except for a particularly loud event. Owing to the analogy between fields in curved spacetime and waves propagating in a flowing medium, QNMs can be equally excited in a laboratory. In these finite-sized systems, the QNM spectrum is expected to alter: compared to their counterparts in unbounded settings, the real frequencies of QNMs shift while their damping rates (imaginary frequencies) reduce, thereby enhancing their detectability. Here we show that multiple QNMs can be extracted from noise-driven interface waves surrounding a giant quantum vortex in superfluid helium-4, which emulates a spacetime geometry indicative of a rotating black hole. By resolving waves with different azimuthal periodicity, we find that both fundamental modes and their higher-frequency overtones are excited, and oscillate at frequencies given by the size of our system. Since similar effects may arise in astrophysical scenarios due to the interstellar medium or dark matter, gravity simulators now complement numerical and observational approaches to black-hole spectroscopy.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The manuscript claims to perform black-hole spectroscopy in an analog system by extracting multiple quasinormal modes (QNMs), including fundamentals and overtones, from noise-driven interface waves around a giant quantum vortex in superfluid helium-4. The vortex is said to emulate a rotating black-hole spacetime; waves with different azimuthal periodicities are resolved, and the observed frequencies are reported to be set by the finite system size, with finite-size effects shifting real parts and reducing damping rates relative to unbounded cases.

Significance. If the extracted frequencies and damping rates are shown to match the QNM spectrum computed from the measured superfluid velocity profile via the effective metric, the work would supply a laboratory realization of analog spectroscopy that accesses overtones and illustrates finite-size modifications potentially relevant to astrophysical environments. The experimental resolution of azimuthal modes constitutes a technical step forward for analog gravity.

major comments (2)
  1. [Abstract] Abstract: the claim that the observed waves constitute QNMs of the Kerr-like analog geometry is load-bearing, yet the text states only that frequencies 'oscillate at frequencies given by the size of our system.' An explicit, quantitative comparison of both real frequencies and (unmentioned) damping rates to the spectrum obtained by solving the wave equation on the measured velocity profile is required to distinguish the analog QNMs from generic confined-wave dispersion; without this comparison the spectroscopy interpretation does not follow.
  2. [Abstract] The mapping from azimuthal periodicity to black-hole angular-momentum modes must be validated against the effective-metric prediction; azimuthal resolution alone does not establish that the observed spectrum reproduces the damping rates or the specific frequency ratios expected from the vortex flow rather than boundary or superfluid dispersion effects.
minor comments (1)
  1. The abstract would be strengthened by quoting at least one measured frequency, its uncertainty, and the corresponding theoretical value from the effective metric.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their thoughtful review and constructive suggestions. We address the major comments point by point below and agree that explicit quantitative comparisons will strengthen the spectroscopy interpretation.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the claim that the observed waves constitute QNMs of the Kerr-like analog geometry is load-bearing, yet the text states only that frequencies 'oscillate at frequencies given by the size of our system.' An explicit, quantitative comparison of both real frequencies and (unmentioned) damping rates to the spectrum obtained by solving the wave equation on the measured velocity profile is required to distinguish the analog QNMs from generic confined-wave dispersion; without this comparison the spectroscopy interpretation does not follow.

    Authors: We agree that an explicit side-by-side comparison of both real frequencies and damping rates to the QNM spectrum computed from the measured velocity profile via the effective metric is necessary to firmly establish the analog QNM interpretation over generic confined-wave effects. The manuscript already reports that finite-size effects shift real parts and reduce damping relative to unbounded cases, and the velocity profile is measured, but we will add a new figure and accompanying text in the revised manuscript that solves the wave equation on the effective metric and directly overlays the predicted frequencies and damping rates with the extracted experimental values for each azimuthal mode. revision: yes

  2. Referee: [Abstract] The mapping from azimuthal periodicity to black-hole angular-momentum modes must be validated against the effective-metric prediction; azimuthal resolution alone does not establish that the observed spectrum reproduces the damping rates or the specific frequency ratios expected from the vortex flow rather than boundary or superfluid dispersion effects.

    Authors: We acknowledge the need to validate the mode identification beyond azimuthal periodicity alone. The manuscript associates different azimuthal periodicities with black-hole angular-momentum modes on the basis of the vortex flow, but to address this directly we will include in the revision a quantitative comparison of the observed frequency ratios and damping rates against the predictions of the effective metric for the corresponding modes. This will help rule out dominant contributions from boundary or intrinsic superfluid dispersion. revision: yes

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The paper reports an experimental extraction of multiple quasinormal modes from noise-driven interface waves in a finite-sized quantum vortex analog of a Kerr black hole. Frequencies are stated to be set by system size, with the central claim resting on resolution of azimuthal modes and comparison to the effective metric derived from the measured superfluid velocity profile. This comparison is presented as an empirical result rather than a definitional equivalence, a fitted parameter renamed as prediction, or a self-citation chain that reduces the claim to its own inputs. No self-definitional steps, uniqueness theorems imported from prior author work, or ansatzes smuggled via citation are evident in the abstract or described derivation. The result is self-contained against external benchmarks of wave measurements in the analog system.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The claim rests on the validity of the analog-gravity mapping between the superfluid vortex flow and Kerr spacetime, plus the assumption that azimuthal periodicity directly labels the black-hole quasinormal modes.

axioms (1)
  • domain assumption The established analogy between waves in a flowing fluid and fields in curved spacetime extends to the quasinormal-mode spectrum of a rotating black hole.
    Invoked when the paper states that the vortex emulates a rotating black-hole geometry.

pith-pipeline@v0.9.0 · 5787 in / 1259 out tokens · 43018 ms · 2026-05-23T02:47:35.913981+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Forward citations

Cited by 2 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Analog regular black holes and black hole mimickers for surface-gravity waves in fluids

    gr-qc 2026-04 unverdicted novelty 7.0

    Surface-gravity waves in shallow water can be configured with central and graded drainage to analogize regular black holes and mimickers, enabling lab study of their instabilities.

  2. Spectroscopy of analogue black holes using simulation-based inference

    gr-qc 2026-04 unverdicted novelty 5.0

    Simulation-based inference reliably extracts physical parameters from noisy spectra of analogue black holes.

Reference graph

Works this paper leans on

62 extracted references · 62 canonical work pages · cited by 2 Pith papers

  1. [1]

    Destounis and F

    K. Destounis and F. Duque, Black-hole spectroscopy: Quasinormal modes, ringdown stability and the pseu- dospectrum, in Compact Objects in the Universe , edited by E. Papantonopoulos and N. Mavromatos (Springer Nature Switzerland, Cham, 2024) p. 155–202

    work page 2024

  2. [2]

    K. D. Kokkotas and B. G. Schmidt, Quasi-normal modes of stars and black holes, Living Rev. Relativ. 2, 2 (1999)

    work page 1999

  3. [3]

    R. A. Konoplya and A. Zhidenko, Quasinormal modes of black holes: From astrophysics to string theory, Rev. Mod. Phys. 83, 793–836 (2011)

    work page 2011

  4. [4]

    Berti, V

    E. Berti, V. Cardoso, and A. O. Starinets, Quasinormal modes of black holes and black branes, Class. Quant. Grav. 26, 163001 (2009)

    work page 2009

  5. [5]

    Baibhav et al

    V. Baibhav et al. , Agnostic black hole spectroscopy: Quasinormal mode content of numerical relativity wave- forms and limits of validity of linear perturbation theory, Phys. Rev. D 108, 104020 (2023)

    work page 2023

  6. [6]

    P. J. Nee, S. H. V¨ olkel, and H. P. Pfeiffer, Role of black hole quasinormal mode overtones for ringdown analysis, Phys. Rev. D 108, 044032 (2023)

    work page 2023

  7. [7]

    Barausse, V

    E. Barausse, V. Cardoso, and P. Pani, Can environmental effects spoil precision gravitational-wave astrophysics?, Phys. Rev. D 89, 104059 (2014)

    work page 2014

  8. [8]

    Cardoso, K

    V. Cardoso, K. Destounis, F. Duque, R. P. Macedo, and A. Maselli, Black holes in galaxies: Environmental im- pact on gravitational-wave generation and propagation, Phys. Rev. D 105, L061501 (2022)

    work page 2022

  9. [9]

    ˇSvanˇ caraet al., Rotating curved spacetime signatures from a giant quantum vortex, Nature 628, 66–70 (2024)

    P. ˇSvanˇ caraet al., Rotating curved spacetime signatures from a giant quantum vortex, Nature 628, 66–70 (2024)

    work page 2024

  10. [10]

    Solidoro, S

    L. Solidoro, S. Patrick, R. Gregory, and S. Weinfurt- ner, Quasinormal modes in semi-open systems (2024), arXiv:2406.11013 [gr-qc]

    work page arXiv 2024

  11. [11]

    Hung et al

    C.-L. Hung et al. , From cosmology to cold atoms: Ob- servation of Sakharov oscillations in a quenched atomic superfluid, Science 341, 1213–1215 (2013)

    work page 2013

  12. [12]

    Eckel, A

    S. Eckel, A. Kumar, T. Jacobson, I. B. Spielman, and G. K. Campbell, A rapidly expanding Bose-Einstein con- densate: An expanding Universe in the lab, Phys. Rev. X 8, 021021 (2018)

    work page 2018

  13. [13]

    Jacquet et al

    M. Jacquet et al. , Polariton fluids for analogue gravity physics, Phil. Trans. R. Soc. A 378, 20190225 (2020)

    work page 2020

  14. [14]

    Navon et al

    N. Navon et al. , Quantum gases in optical boxes, Nat. Phys. 17, 1334–1341 (2021)

    work page 2021

  15. [15]

    Viermann et al., Quantum field simulator for dynam- ics in curved spacetime, Nature 611, 260–264 (2022)

    C. Viermann et al., Quantum field simulator for dynam- ics in curved spacetime, Nature 611, 260–264 (2022)

    work page 2022

  16. [16]

    Barcel´ o, S

    C. Barcel´ o, S. Liberati, and M. Visser, Analogue gravity, Living Rev. Relativ. 14, 3 (2011)

    work page 2011

  17. [17]

    Berti et al., Testing general relativity with present and future astrophysical observations, Class

    E. Berti et al., Testing general relativity with present and future astrophysical observations, Class. Quantum Grav. 32, 243001 (2015)

    work page 2015

  18. [18]

    Weinfurtner, E

    S. Weinfurtner, E. W. Tedford, M. C. J. Penrice, W. G. Unruh, and G. A. Lawrence, Measurement of stimulated Hawking emission in an analogue system, Phys. Rev. Lett. 106, 021302 (2011)

    work page 2011

  19. [19]

    Euv´ e, F

    L.-P. Euv´ e, F. Michel, R. Parentani, T. G. Philbin, and G. Rousseaux, Observation of noise correlated by the Hawking effect in a water tank, Phys. Rev. Lett. 117, 121301 (2016)

    work page 2016

  20. [20]

    V. I. Kolobov, K. Golubkov, J. R. Mu˜ noz de Nova, and J. Steinhauer, Observation of stationary spontaneous Hawking radiation and the time evolution of an analogue black hole, Nat. Phys. 17, 362–367 (2021)

    work page 2021

  21. [21]

    Torres et al., Rotational superradiant scattering in a vortex flow, Nat

    T. Torres et al., Rotational superradiant scattering in a vortex flow, Nat. Phys. 13, 833–836 (2017)

    work page 2017

  22. [22]

    Cromb et al., Amplification of waves from a rotating body, Nat

    M. Cromb et al., Amplification of waves from a rotating body, Nat. Phys. 16, 1069–1073 (2020)

    work page 2020

  23. [23]

    M. C. Braidotti et al. , Measurement of Penrose super- radiance in a photon superfluid, Phys. Rev. Lett. 128, 013901 (2022)

    work page 2022

  24. [24]

    Cardoso, J

    V. Cardoso, J. P. S. Lemos, and S. Yoshida, Quasinormal modes and stability of the rotating acoustic black hole: Numerical analysis, Phys. Rev. D 70, 124032 (2004)

    work page 2004

  25. [25]

    Patrick, A

    S. Patrick, A. Coutant, M. Richartz, and S. Weinfurtner, Black hole quasibound states from a draining bathtub vortex flow, Phys. Rev. Lett. 121, 061101 (2018)

    work page 2018

  26. [26]

    Torres, S

    T. Torres, S. Patrick, M. Richartz, and S. Weinfurtner, Analogue black hole spectroscopy; or, how to listen to dumb holes, Class. Quant. Grav. 36, 194002 (2019)

    work page 2019

  27. [27]

    Geelmuyden, S

    A. Geelmuyden, S. Erne, S. Patrick, C. F. Barenghi, and S. Weinfurtner, Sound-ring radiation of expanding vortex clusters, Phys. Rev. Res. 4, 023099 (2022)

    work page 2022

  28. [28]

    M. J. Jacquet et al. , Quantum vacuum excitation of a quasinormal mode in an analog model of black hole space- time, Phys. Rev. Lett. 130, 111501 (2023)

    work page 2023

  29. [29]

    Burgess, S

    C. Burgess, S. Patrick, T. Torres, R. Gregory, and F. K¨ onig, Quasinormal modes of optical solitons, Phys. Rev. Lett. 132, 053802 (2024). 7

    work page 2024

  30. [30]

    Torres, S

    T. Torres, S. Patrick, M. Richartz, and S. Weinfurtner, Quasinormal mode oscillations in an analogue black hole experiment, Phys. Rev. Lett. 125, 011301 (2020)

    work page 2020

  31. [31]

    R. J. Donnelly and C. F. Barenghi, The observed prop- erties of liquid helium at the saturated vapor pressure, J. Phys. Chem. Ref. Data 27, 1217–1274 (1998)

    work page 1998

  32. [32]

    Moisy, M

    F. Moisy, M. Rabaud, and K. Salsac, A synthetic Schlieren method for the measurement of the topography of a liquid interface, Exp. Fluids 46, 1021–1036 (2009)

    work page 2009

  33. [33]

    Wildeman, Real-time quantitative Schlieren imaging by fast Fourier demodulation of a checkered backdrop, Exp

    S. Wildeman, Real-time quantitative Schlieren imaging by fast Fourier demodulation of a checkered backdrop, Exp. Fluids 59, 97 (2018)

    work page 2018

  34. [34]

    Andersen, T

    A. Andersen, T. Bohr, B. Stenum, J. J. Rasmussen, and B. Lautrup, Anatomy of a bathtub vortex, Phys. Rev. Lett. 91, 104502 (2003)

    work page 2003

  35. [35]

    Patrick and S

    S. Patrick and S. Weinfurtner, Superradiance in disper- sive black hole analogues, Phys. Rev. D 102, 084041 (2020)

    work page 2020

  36. [36]

    B¨ uhler,Waves and Mean Flows (Cambridge Univer- sity Press, Cambridge, 2014)

    O. B¨ uhler,Waves and Mean Flows (Cambridge Univer- sity Press, Cambridge, 2014)

    work page 2014

  37. [37]

    Cardoso, A

    V. Cardoso, A. S. Miranda, E. Berti, H. Witek, and V. T. Zanchin, Geodesic stability, Lyapunov exponents, and quasinormal modes, Phys. Rev. D 79, 064016 (2009)

    work page 2009

  38. [38]

    Torres, A

    T. Torres, A. Coutant, S. Dolan, and S. Weinfurtner, Waves on a vortex: rays, rings and resonances, J. Fluid Mech. 857, 291–311 (2018)

    work page 2018

  39. [39]

    Akiyama et al

    K. Akiyama et al. (The Event Horizon Telescope Collab- oration), First M87 Event Horizon Telescope results. I. the shadow of the supermassive black hole, Astrophys. J. Lett. 875, L1 (2019)

    work page 2019

  40. [40]

    Ma and H

    S. Ma and H. Yang, Excitation of quadratic quasinormal modes for kerr black holes, Phys. Rev. D 109, 104070 (2024)

    work page 2024

  41. [41]

    T. F. M. Spieksma, V. Cardoso, G. Carullo, M. Della Rocca, and F. Duque, Black hole spectroscopy in environments: Detectability prospects, Phys. Rev. Lett. 134, 081402 (2025)

    work page 2025

  42. [42]

    Roy and R

    S. Roy and R. Vicente, Compact binary coalescences in dense environments can pose as in vacuum (2024), arXiv:2410.16388 [gr-qc]

    work page arXiv 2024

  43. [43]

    Cannizzaro, A

    E. Cannizzaro, A. Caputo, L. Sberna, and P. Pani, Plasma-photon interaction in curved spacetime: Formal- ism and quasibound states around nonspinning black holes, Phys. Rev. D 103, 124018 (2021)

    work page 2021

  44. [44]

    O. A. Hannuksela et al., Probing the existence of ultra- light bosons with a single gravitational-wave measure- ment, Nat. Astron. 3, 447–451 (2019)

    work page 2019

  45. [45]

    T. F. M. Spieksma, E. Cannizzaro, T. Ikeda, V. Car- doso, and Y. Chen, Superradiance: Axionic couplings and plasma effects, Phys. Rev. D 108, 063013 (2023)

    work page 2023

  46. [46]

    G. T. Horowitz and V. E. Hubeny, Quasinormal modes of AdS black holes and the approach to thermal equilibrium, Phys. Rev. D 62, 024027 (2000)

    work page 2000

  47. [47]

    Cardoso and J

    V. Cardoso and J. P. S. Lemos, Quasinormal modes of Schwarzschild anti-de Sitter black holes: Electromagnetic and gravitational perturbations, Phys. Rev. D64, 084017 (2001)

    work page 2001

  48. [48]

    Cardoso, R

    V. Cardoso, R. Konoplya, and J. P. S. Lemos, Quasinor- mal frequencies of Schwarzschild black holes in anti-de Sitter space-times: A Complete study on the asymptotic behavior, Phys. Rev. D 68, 044024 (2003)

    work page 2003

  49. [49]

    S. M. D. Gregory, S. Schiattarella, V. S. Barroso, D. I. Kaiser, A. Avgoustidis, and S. Weinfurtner, Tracking the nonlinear formation of an interfacial wave spectral cas- cade from one to few to many (2025), arXiv:2410.08842 [gr-qc]

    work page arXiv 2025

  50. [50]

    H. Yang, A. Zimmerman, and L. Lehner, Turbulent black holes, Phys. Rev. Lett. 114, 081101 (2015)

    work page 2015

  51. [51]

    Visser and S

    M. Visser and S. Weinfurtner, Vortex analogue for the equatorial geometry of the Kerr black hole, Class. Quan- tum Gravity 22, 2493 (2005)

    work page 2005

  52. [52]

    H. Yano, K. Ohyama, K. Obara, and O. Ishikawa, Obser- vation of the spiral flow and vortex induced by a suction pump in superfluid 4He, J. Phys. Conf. Ser. 969, 012002 (2018)

    work page 2018

  53. [53]

    C. F. Barenghi, L. Skrbek, and K. R. Sreenivasan, Quantum Turbulence (Cambridge University Press, Cam- bridge, 2023)

    work page 2023

  54. [54]

    R. P. Feynman, Application of quantum mechanics to liquid helium, in Progress in Low Temperature Physics , Vol. 1, edited by C. J. Gorter (Elsevier, Amsterdam,

    work page

  55. [55]

    S. E. Perez Bergliaffa, K. Hibberd, M. Stone, and M. Visser, Wave equation for sound in fluids with vor- ticity, Physica D 191, 121–136 (2004)

    work page 2004

  56. [56]

    L. A. Oliveira, C. L. Benone, and L. C. B. Crispino, Er- goregion instability in a fluid with vorticity, Phys. Rev. D 110, 124047 (2024)

    work page 2024

  57. [57]

    Patrick and L

    S. Patrick and L. Solidoro, Quasinormal modes in lorentz violating black hole analogues (2025), arXiv:2007.06671 [gr-qc]

    work page arXiv 2025

  58. [58]

    Berti, V

    E. Berti, V. Cardoso, and J. P. S. Lemos, Quasinormal modes and classical wave propagation in analogue black holes, Phys. Rev. D 70, 124006 (2004)

    work page 2004

  59. [59]

    Iyer and C

    S. Iyer and C. M. Will, Black-hole normal modes: A WKB approach. I. Foundations and application of a higher-order WKB analysis of potential-barrier scatter- ing, Phys. Rev. D 35, 3621–3631 (1987)

    work page 1987

  60. [60]

    Torres, Estimate of the superradiance spectrum in dis- persive media, Philos

    T. Torres, Estimate of the superradiance spectrum in dis- persive media, Philos. Trans. R. Soc. A 378, 20190236 (2020)

    work page 2020

  61. [61]

    E. R. Tracy, A. J. Brizard, A. S. Richardson, and A. N. Kaufman, Ray Tracing and Beyond: Phase Space Methods in Plasma Wave Theory (Cambridge University Press, Cambridge, 2014)

    work page 2014

  62. [62]

    Patrick and T

    S. Patrick and T. Torres, Primer on the analog black hole bomb with capillary-gravity waves, Phys. Rev. D 110, 124068 (2024). 8 METHODS A. Experimental set-up The simulation of a curved spacetime indicative of ro- tating black holes [51] is based on a draining vortex flow of superfluid helium. The flow is initiated and main- tained due to a centrifugal pu...

    work page 2024