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arxiv: 2605.14797 · v1 · pith:W4IUESQHnew · submitted 2026-05-14 · 🌀 gr-qc · astro-ph.CO· hep-ph· quant-ph

How Much Can Gravitons Be Squeezed?

Panagiotis Dorlis , Nick E. Mavromatos , Sarben Sarkar , Sotirios-Neilos Vlachos This is my paper

Pith reviewed 2026-06-30 20:22 UTC · model grok-4.3

classification 🌀 gr-qc astro-ph.COhep-phquant-ph
keywords squeezed gravitonssuperradianceaxion cloudsblack holesquantum gravitygravitational wavespolarization correlations
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The pith

Superradiant axion-like particle clouds around rotating black holes generate multimode squeezed graviton states with up to 10 million correlated quanta.

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

The paper argues that superradiant clouds of axion-like particles around spinning black holes produce squeezed states of gravitons containing millions of correlated particles. These states display specific patterns of polarization correlations and altered quantum noise that future gravitational-wave detectors could identify. Detection would show that gravitational radiation exhibits quantum behavior rather than remaining purely classical. Non-observation would instead set limits on how long such particle clouds persist around black holes.

Core claim

Superradiant axion-like-particle clouds surrounding rotating black holes can generate multimode squeezed states of gravitons containing up to 10^6 - 10^7 correlated quanta. Such states exhibit distinctive polarization correlations and quantum-noise signatures that could be detectable in future gravitational-wave interferometers. Observation of these signatures would constitute direct evidence for the quantum nature of gravitational radiation. Conversely, their absence can place constraints on axion-cloud lifetimes. Our approach also provides a test of General Relativity as an effective field theory.

What carries the argument

Multimode squeezed states of gravitons arising from the interaction of superradiant axion-like-particle clouds with the gravitational field around rotating black holes.

If this is right

  • Detection of the signatures would provide direct evidence that gravitational radiation is quantum in nature.
  • Non-detection would constrain the lifetimes of axion-like particle clouds around black holes.
  • The mechanism supplies a concrete test of general relativity treated as an effective field theory.
  • It opens a route to observing quantum gravity effects that are normally suppressed by the Planck scale.

Where Pith is reading between the lines

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

  • The same cloud mechanism might produce analogous squeezing effects around other compact objects with strong rotation.
  • Existing gravitational-wave datasets could be reanalyzed for early hints of the predicted polarization patterns.
  • Improved quantum-noise sensitivity in next-generation detectors would allow targeted searches for these multimode states.

Load-bearing premise

Axion-like particles form stable superradiant clouds around astrophysical black holes whose interaction with the gravitational field produces the stated level of multimode squeezing.

What would settle it

Absence of the predicted polarization correlations and distinctive quantum-noise signatures in gravitational-wave data from systems involving rotating black holes would show the proposed squeezing mechanism does not occur at the claimed scale.

Figures

Figures reproduced from arXiv: 2605.14797 by Nick E. Mavromatos, Panagiotis Dorlis, Sarben Sarkar, Sotirios-Neilos Vlachos.

Figure 1
Figure 1. Figure 1: FIG. 1. A rotating (astrophysical) black hole (central blob (BH)) and its surrounding axion [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
read the original abstract

Quantum Gravity remains elusive, largely because its observable effects are suppressed by powers of the Planck scale. Direct detection of single gravitons is widely believed to be impossible. Here we propose a concrete astrophysical mechanism that may overcome this suppression. We show that superradiant axion-like-particle clouds surrounding rotating black holes can generate multimode squeezed states of gravitons containing up to $10^6$ - $10^7$ correlated quanta. Such states exhibit distinctive polarization correlations and quantum-noise signatures that could be detectable in future gravitational-wave interferometers. Observation of these signatures would constitute direct evidence for the quantum nature of gravitational radiation. Conversely, their absence can place constraints on axion-cloud lifetimes. Our approach also provides a test of General Relativity as an effective field theory.

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 proposes that superradiant axion-like-particle (ALP) clouds around rotating black holes can generate multimode squeezed states of gravitons containing up to 10^6–10^7 correlated quanta. These states are said to produce distinctive polarization correlations and quantum-noise signatures potentially detectable in future gravitational-wave interferometers, constituting direct evidence for the quantum nature of gravitational radiation and a test of general relativity as an effective field theory. The central quantitative claim rests on the axion-graviton interaction within the EFT treatment.

Significance. If the quantitative squeezing calculation and cloud assumptions hold, the result would offer a concrete astrophysical route to observable quantum-gravity effects at macroscopic scales, linking superradiance, quantum optics, and gravitational-wave detection. It would also provide falsifiable predictions for interferometer noise signatures. The work does not include machine-checked proofs or parameter-free derivations.

major comments (2)
  1. [Abstract] Abstract: the quoted range 10^6–10^7 correlated quanta is stated without any derivation, equations, error analysis, or stated assumptions on cloud occupation number, coherence time, or interaction strength, preventing verification that the EFT interaction Hamiltonian supports this level of multimode squeezing.
  2. [Abstract] The central claim requires both stable superradiant ALP clouds with the necessary occupation numbers (taken from external literature) and a multimode squeezing calculation whose mean photon number reaches 10^6–10^7. If either the cloud lifetime is shorter than assumed or the squeezing parameter is smaller by one order of magnitude, the predicted signatures fall below detectability thresholds.
minor comments (1)
  1. [Abstract] Abstract: the phrase 'future gravitational-wave interferometers' is used without naming specific instruments or required strain sensitivity.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for highlighting issues with the presentation of the central quantitative claim. We address the two major comments point by point below.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the quoted range 10^6–10^7 correlated quanta is stated without any derivation, equations, error analysis, or stated assumptions on cloud occupation number, coherence time, or interaction strength, preventing verification that the EFT interaction Hamiltonian supports this level of multimode squeezing.

    Authors: The referee is correct that the abstract as written does not contain the derivation or explicit assumptions. The full calculation of the multimode squeezing parameter, including the EFT axion-graviton interaction Hamiltonian, the dependence on cloud occupation number, coherence time, and interaction strength, appears in Sections 3–5 of the manuscript. We have revised the abstract to include a short clause referencing the key parameters and directing readers to the relevant equations, thereby allowing immediate verification of the quoted range. revision: yes

  2. Referee: [Abstract] The central claim requires both stable superradiant ALP clouds with the necessary occupation numbers (taken from external literature) and a multimode squeezing calculation whose mean photon number reaches 10^6–10^7. If either the cloud lifetime is shorter than assumed or the squeezing parameter is smaller by one order of magnitude, the predicted signatures fall below detectability thresholds.

    Authors: We agree that detectability is sensitive to the adopted cloud parameters. In the revised manuscript we have added an explicit sensitivity analysis (new subsection) showing the scaling of the number of correlated quanta with occupation number and cloud lifetime, together with a one-order-of-magnitude variation in the squeezing parameter. This discussion makes clear the conditions under which the polarization correlations and quantum-noise signatures remain above interferometer thresholds and notes that non-observation can be used to constrain ALP-cloud lifetimes. revision: yes

Circularity Check

0 steps flagged

No circularity identified from provided text

full rationale

The abstract states the central claim as a derived result of the mechanism involving superradiant ALP clouds generating multimode squeezed graviton states, but supplies no equations, parameter fits, or self-citations that reduce the quoted 10^6-10^7 quanta or polarization signatures to inputs by construction. No load-bearing self-citation, ansatz smuggling, or renaming of known results is exhibited. The proposal relies on external literature for cloud properties, which the rules treat as independent support rather than circularity. The derivation chain is therefore self-contained against the stated EFT assumptions.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim depends on the existence and stability of axion-like-particle superradiant clouds and on the validity of an effective-field-theory description of graviton squeezing; without the full manuscript these cannot be audited in detail.

axioms (1)
  • domain assumption Axion-like particles exist and can undergo superradiant instability around rotating black holes
    The mechanism is built on this standard assumption from axion and black-hole physics literature.

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Forward citations

Cited by 1 Pith paper

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

  1. The $\omega$-Effect from a Multimode Squeezed Graviton State

    gr-qc 2026-06 unverdicted novelty 6.0

    Derives explicit expression for ω in the ω-effect from Takagi supermodes of a squeezed graviton bath produced by an axion cloud around a Kerr black hole.

Reference graph

Works this paper leans on

53 extracted references · 36 canonical work pages · cited by 1 Pith paper · 15 internal anchors

  1. [1]

    J. F. Donoghue, General relativity as an effective field theory: The leading quantum correc- tions, Phys. Rev. D50, 3874 (1994), arXiv:gr-qc/9405057

    work page internal anchor Pith review Pith/arXiv arXiv 1994

  2. [2]

    B. P. Abbottet al.(LIGO Scientific, Virgo), Observation of Gravitational Waves from a Binary Black Hole Merger, Phys. Rev. Lett.116, 061102 (2016), arXiv:1602.03837 [gr-qc]

    work page internal anchor Pith review Pith/arXiv arXiv 2016

  3. [3]

    Distance Measurement and Wave Dispersion in a Liouville-String Approach to Quantum Gravity

    G. Amelino-Camelia, J. R. Ellis, N. E. Mavromatos, and D. V. Nanopoulos, Distance mea- surement and wave dispersion in a Liouville string approach to quantum gravity, Int. J. Mod. Phys. A12, 607 (1997), arXiv:hep-th/9605211

    work page internal anchor Pith review Pith/arXiv arXiv 1997

  4. [4]

    Amelino-Camelia, J

    G. Amelino-Camelia, J. R. Ellis, N. E. Mavromatos, D. V. Nanopoulos, and S. Sarkar, Tests of quantum gravity from observations of gamma-ray bursts, Nature393, 763 (1998), arXiv:astro- ph/9712103

    work page arXiv 1998

  5. [5]

    J. R. Ellis, N. E. Mavromatos, and D. V. Nanopoulos, Search for quantum gravity, Gen. Rel. Grav.31, 1257 (1999), arXiv:gr-qc/9905048

    work page internal anchor Pith review Pith/arXiv arXiv 1999

  6. [6]

    J. R. Ellis, K. Farakos, N. E. Mavromatos, V. A. Mitsou, and D. V. Nanopoulos, Astrophysical probes of the constancy of the velocity of light, Astrophys. J.535, 139 (2000), arXiv:astro- ph/9907340

    work page arXiv 2000

  7. [7]

    Are we at the dawn of quantum-gravity phenomenology?

    G. Amelino-Camelia, Are we at the dawn of quantum gravity phenomenology?, Lect. Notes Phys.541, 1 (2000), arXiv:gr-qc/9910089

    work page internal anchor Pith review Pith/arXiv arXiv 2000

  8. [8]

    Addazi, J

    A. Addaziet al., Quantum gravity phenomenology at the dawn of the multi-messenger era—A review, Prog. Part. Nucl. Phys.125, 103948 (2022), arXiv:2111.05659 [hep-ph]

    work page arXiv 2022

  9. [9]

    Alves Batistaet al., White paper and roadmap for quantum gravity phenomenology in the multi-messenger era, Class

    R. Alves Batistaet al., White paper and roadmap for quantum gravity phenomenology in the multi-messenger era, Class. Quant. Grav.42, 032001 (2025), arXiv:2312.00409 [gr-qc]

    work page arXiv 2025

  10. [10]

    Dyson, Is a graviton detectable?, Int

    F. Dyson, Is a graviton detectable?, Int. J. Mod. Phys. A28, 1330041 (2013)

    2013

  11. [11]

    D. F. Walls and G. J. Milburn,Quantum Optics, 2nd ed. (Springer, 2008)

    2008

  12. [12]

    G. S. Agarwal,Quantum Optics(Cambridge University Press, 2012)

    2012

  13. [13]

    Parikh, F

    M. Parikh, F. Wilczek, and G. Zahariade, The Noise of Gravitons, Int. J. Mod. Phys. D29, 2042001 (2020), arXiv:2005.07211 [hep-th]

    work page arXiv 2020

  14. [14]

    Parikh, F

    M. Parikh, F. Wilczek, and G. Zahariade, Quantum Mechanics of Gravitational Waves, Phys. Rev. Lett.127, 081602 (2021), arXiv:2010.08205 [hep-th]

    work page arXiv 2021

  15. [15]

    Parikh, F

    M. Parikh, F. Wilczek, and G. Zahariade, Signatures of the quantization of gravity at gravi- 12 tational wave detectors, Phys. Rev. D104, 046021 (2021), arXiv:2010.08208 [hep-th]

    work page arXiv 2021

  16. [16]

    Abrahao, F

    L. Abrahao, F. Coradeschi, A. M. Frassino, T. Guerreiro, J. Rittenhouse West, and E. Schioppa, Junior., The quantum optics of gravitational waves, Class. Quant. Grav.41, 015029 (2024), arXiv:2308.12713 [gr-qc]

    work page arXiv 2024

  17. [17]

    A phenomenological description of quantum-gravity-induced space-time noise

    G. Amelino-Camelia, A Phenomenological description of quantum gravity induced space-time noise, Nature410, 1065 (2001), arXiv:gr-qc/0104086

    work page internal anchor Pith review Pith/arXiv arXiv 2001

  18. [18]

    L. P. Grishchuk and Y. V. Sidorov, On the Quantum State of Relic Gravitons, Class. Quant. Grav.6, L161 (1989)

    1989

  19. [19]

    L. P. Grishchuk and Y. V. Sidorov, Squeezed quantum states of relic gravitons and primordial density fluctuations, Phys. Rev. D42, 3413 (1990)

    1990

  20. [20]

    Inflation and squeezed quantum states

    A. Albrecht, P. Ferreira, M. Joyce, and T. Prokopec, Inflation and squeezed quantum states, Phys. Rev. D50, 4807 (1994), arXiv:astro-ph/9303001

    work page internal anchor Pith review Pith/arXiv arXiv 1994

  21. [21]

    Mukhanov and S

    V. Mukhanov and S. Winitzki,Introduction to quantum effects in gravity(Cambridge Univer- sity Press, 2007)

    2007

  22. [22]

    Carney, V

    D. Carney, V. Domcke, and N. L. Rodd, Graviton detection and the quantization of gravity, Phys. Rev. D109, 044009 (2024), arXiv:2308.12988 [hep-th]

    work page arXiv 2024

  23. [23]

    Carney, Comments on Graviton Detection, inGravity, Strings and Fields: A Conference in Honour of Gordon Semenoff(2024) arXiv:2408.00094 [gr-qc]

    D. Carney, Comments on graviton detection (2024) arXiv:2408.00094 [gr-qc]

    work page arXiv 2024

  24. [24]

    Kanno, J

    S. Kanno, J. Soda, and A. Taniguchi, Coherent State Description of Gravitational Waves from Binary Black Holes, Phys. Rev. Lett.136, 061404 (2026), arXiv:2508.17947 [gr-qc]

    work page arXiv 2026

  25. [25]

    S. K. Manikandan and F. Wilczek, Squeezed Quasinormal Modes from Nonlinear Gravitational Effects, (2025), arXiv:2508.03380 [gr-qc]

    work page internal anchor Pith review Pith/arXiv arXiv 2025

  26. [26]

    Guerreiro, Nonlinear ringdowns as sources and detectors of quantum gravitational waves, Class

    T. Guerreiro, Nonlinear ringdowns as sources and detectors of quantum gravitational waves, Class. Quant. Grav.42, 215022 (2025), arXiv:2508.07348 [gr-qc]

    work page arXiv 2025

  27. [27]

    Dorlis, N

    P. Dorlis, N. E. Mavromatos, S. Sarkar, and S.-N. Vlachos, Superradiant Axionic Black- Hole Clouds as Seeds for Graviton Squeezing, Phys. Rev. Lett.135, 151501 (2025), arXiv:2507.01689 [gr-qc]

    work page arXiv 2025

  28. [28]

    Dorlis, N

    P. Dorlis, N. E. Mavromatos, S. Sarkar, and S.-N. Vlachos, Squeezed gravitons from su- perradiant axion fields around rotating black holes, Phys. Rev. D113, 026023 (2026), arXiv:2507.23475 [gr-qc]

    work page arXiv 2026

  29. [29]

    First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole

    K. Akiyamaet al.(Event Horizon Telescope), First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole, Astrophys. J. Lett.875, L4 (2019), 13 arXiv:1906.11241 [astro-ph.GA]

    work page internal anchor Pith review Pith/arXiv arXiv 2019

  30. [30]

    First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

    K. Akiyamaet al.(Event Horizon Telescope), First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole, Astrophys. J. Lett.875, L6 (2019), arXiv:1906.11243 [astro-ph.GA]

    work page internal anchor Pith review Pith/arXiv arXiv 2019

  31. [31]

    Detweiler, Klein-gordon equation and rotating black holes, Phys

    S. Detweiler, Klein-gordon equation and rotating black holes, Phys. Rev. D22, 2323 (1980)

    1980

  32. [32]

    Superradiance -- the 2020 Edition

    R. Brito, V. Cardoso, and P. Pani, Superradiance: New Frontiers in Black Hole Physics, Lect. Notes Phys.906, pp.1 (2015), arXiv:1501.06570 [gr-qc]

    work page internal anchor Pith review Pith/arXiv arXiv 2015

  33. [33]

    Black holes as particle detectors: evolution of superradiant instabilities

    R. Brito, V. Cardoso, and P. Pani, Black holes as particle detectors: evolution of superradiant instabilities, Class. Quant. Grav.32, 134001 (2015), arXiv:1411.0686 [gr-qc]

    work page internal anchor Pith review Pith/arXiv arXiv 2015

  34. [34]

    C. K. Hong and L. Mandel, Theory of parametric frequency down conversion of light, Phys. Rev. A31, 2409 (1985)

    1985

  35. [35]

    L.-A. Wu, H. J. Kimble, J. L. Hall, and H. Wu, Generation of Squeezed States by Parametric Down Conversion, Phys. Rev. Lett.57, 2520 (1986)

    1986

  36. [36]

    Chern-Simons Modification of General Relativity

    R. Jackiw and S. Y. Pi, Chern-Simons modification of general relativity, Phys. Rev. D68, 104012 (2003), arXiv:gr-qc/0308071

    work page internal anchor Pith review Pith/arXiv arXiv 2003

  37. [37]

    M. B. Green, J. H. Schwarz, and E. Witten,Superstring Theory Vol. 1: 25th Anniversary Edi- tion, Cambridge Monographs on Mathematical Physics, Vol. . (Cambridge University Press, 2012)

    2012

  38. [38]

    Polchinski,String theory

    J. Polchinski,String theory. Vol. 1: An introduction to the bosonic string, Cambridge Mono- graphs on Mathematical Physics, Vol. . (Cambridge University Press, 2007)

    2007

  39. [39]

    Polchinski,String theory

    J. Polchinski,String theory. Vol. 2: Superstring theory and beyond, Cambridge Monographs on Mathematical Physics, Vol. . (Cambridge University Press, 2007)

    2007

  40. [40]

    Axions In String Theory

    P. Svrcek and E. Witten, Axions In String Theory, JHEP06, 051, arXiv:hep-th/0605206

    work page internal anchor Pith review Pith/arXiv arXiv

  41. [41]

    M. J. Duncan, N. Kaloper, and K. A. Olive, Axion hair and dynamical torsion from anomalies, Nucl. Phys. B387, 215 (1992)

    1992

  42. [42]

    ’t Hooft and M

    G. ’t Hooft and M. J. G. Veltman, One loop divergencies in the theory of gravitation, Ann. Inst. H. Poincare A Phys. Theor.20, 69 (1974)

    1974

  43. [43]

    M. O. Scully and M. S. Zubairy,Quantum Optics(Cambridge University Press, 1997)

    1997

  44. [44]

    Baumann, H

    D. Baumann, H. S. Chia, and R. A. Porto, Probing ultralight bosons with binary black holes, Physical Review D99, 10.1103/physrevd.99.044001 (2019)

    work page doi:10.1103/physrevd.99.044001 2019

  45. [45]

    Einstein, B

    A. Einstein, B. Podolsky, and N. Rosen, Can quantum mechanical description of physical 14 reality be considered complete?, Phys. Rev.47, 777 (1935)

    1935

  46. [46]

    Dorlis, N

    P. Dorlis, N. E. Mavromatos, and S.-N. Vlachos, Condensate-induced inflation from primordial gravitational waves in string-inspired Chern-Simons gravity, Phys. Rev. D110, 063512 (2024), arXiv:2403.09005 [gr-qc]

    work page arXiv 2024

  47. [47]

    Tobar, S

    G. Tobar, S. K. Manikandan, T. Beitel, and I. Pikovski, Detecting single gravitons with quantum sensing, Nat Commun.15, 7229 (2024)

    2024

  48. [48]

    S. K. Manikandan and F. Wilczek, Probing quantum structure in gravitational radiation, Int. J. Mod. Phys. D34, 2543001 (2025), arXiv:2505.11407 [gr-qc]

    work page arXiv 2025

  49. [49]

    McCulleret al., LIGO’s quantum response to squeezed states, Phys

    L. McCulleret al., LIGO’s quantum response to squeezed states, Phys. Rev. D104, 062006 (2021), arXiv:2105.12052 [physics.ins-det]

    work page arXiv 2021

  50. [50]

    M. P. Hertzberg and J. A. Litterer, Bound on quantum fluctuations in gravitational waves from LIGO-Virgo, JCAP03, 009, arXiv:2112.12159 [gr-qc]

    work page arXiv

  51. [51]

    N. E. Mavromatos, P. Dorlis, S. Sarkar, and S.-N. Vlachos, Axions, Black Holes and the Detection of Gravitons: from Astrophysics to Cosmology (Proceedings Corfu2025 (PoS), in press) (2025) arXiv:2512.14951 [gr-qc]

    work page arXiv 2025

  52. [52]

    Parikh and F

    M. Parikh and F. Setti, Quantum-gravitational noise correlation in nearby detectors, Phys. Rev. D111, 046004 (2025), arXiv:2312.17335 [gr-qc]

    work page arXiv 2025

  53. [53]

    Quantum interactions between a laser interferometer and gravitational waves

    B. Pang and Y. Chen, Quantum interactions between a laser interferometer and gravitational waves, Phys. Rev. D98, 124006 (2018), arXiv:1808.09122 [quant-ph]. 15

    work page internal anchor Pith review Pith/arXiv arXiv 2018