pith. sign in

arxiv: 2604.19356 · v1 · submitted 2026-04-21 · ❄️ cond-mat.mtrl-sci · cond-mat.mes-hall

True random number generation through stochastic magnonic bistability

Mengying Guo , Zhenyu Zhou , Denys Slobodianiuk , Roman Verba , Krist\'yna Dav\'idkov\'a , Xueyu Guo , Xudong Jing , Yueqi Wang
show 8 more authors
Bj\"orn Heinz Yiheng Rao Carsten Dubs Caihua Wan Xiufeng Han Andrii V. Chumak Philipp Pirro Qi Wang
This is my paper

Pith reviewed 2026-05-10 02:32 UTC · model grok-4.3

classification ❄️ cond-mat.mtrl-sci cond-mat.mes-hall
keywords true random number generatormagnonicsspin wavesbistabilitythermal fluctuationsyttrium iron garnetNIST statistical tests
0
0 comments X

The pith

Thermal fluctuations in the bistable regime of spin-wave dynamics supply true random bits at 20 Mb/s that pass all NIST tests.

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

The paper shows that a simple microstrip patterned on yttrium iron garnet can be biased near its nonlinear bistable regime so that thermal noise alone drives random switching between two stable states. These switches produce bitstreams that meet every statistical test in the NIST SP 800-22 suite while reaching 20 Mb/s. If the mechanism works as described, it supplies a compact physical entropy source that can be fabricated with standard lithography and scaled to nanoscale waveguides, reducing reliance on external or slower randomness generators in integrated circuits.

Core claim

Stochastic switching in the bistable regime of spin-wave dynamics, driven by thermal fluctuations, provides a physical entropy source for true random number generation; the resulting bitstreams from a lithography-patterned YIG microstrip pass all 15 NIST SP 800-22 tests at rates up to 20 Mb/s, a synchronized multiplier increases throughput, and the same principle operates in 200-nm-wide waveguides.

What carries the argument

Stochastic switching between two stable states in the nonlinear bistable regime of spin-wave dynamics, where thermal fluctuations alone set the transition probabilities.

If this is right

  • Synchronized operation of multiple mRNG units implements a random-bit multiplier that multiplies throughput without external post-processing.
  • The same bistable mechanism continues to function when the waveguide width is reduced to 200 nm, enabling integration with nanoscale magnonic circuits.
  • The physical entropy source is generated on-chip using only thermal noise and standard lithography, eliminating the need for external noise sources or complex post-processing circuits.

Where Pith is reading between the lines

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

  • The bistable switching rate could be tuned electrically by adjusting the bias point, offering a way to trade speed for entropy quality in real time.
  • Because the device is based on magnonic waveguides, it could be monolithically integrated with other spin-wave logic or memory elements on the same YIG film.
  • Environmental robustness tests at varying temperatures and magnetic fields would be a direct next step to confirm that the randomness remains device-independent.

Load-bearing premise

Thermal fluctuations near the nonlinear bistable regime supply unbiased, high-entropy randomness without hidden correlations or device-specific artifacts that standard statistical tests would miss.

What would settle it

Observation of systematic bias, long-range correlations, or failure on any NIST test when the device is operated at different temperatures or after repeated fabrication runs would falsify the claim that the output is true randomness.

Figures

Figures reproduced from arXiv: 2604.19356 by Andrii V. Chumak, Bj\"orn Heinz, Caihua Wan, Carsten Dubs, Denys Slobodianiuk, Krist\'yna Dav\'idkov\'a, Mengying Guo, Philipp Pirro, Qi Wang, Roman Verba, Xiufeng Han, Xudong Jing, Xueyu Guo, Yiheng Rao, Yueqi Wang, Zhenyu Zhou.

Figure 1
Figure 1. Figure 1: schematically illustrates the parallel optical and electrical detection for characterizing magnonic random sequences. The core mRNG device consists of a 5-μm-wide gold microstrip antenna fabricated via photolithography on a 330-nm-thick YIG thin film [36]. An external magnetic field of 330 mT is applied out-of￾plane z-axis to study forward volume spin wave propagation [37]. For spin wave excitation, the mi… view at source ↗
Figure 2
Figure 2. Figure 2: Stochastic behavior in magnonic bistable switching. a, μBLS spectra for the up-frequency sweep (black line) and down-frequency sweep (red line) using continue microwave signal, revealing a magnonic bistable window with an 80 MHz frequency gap. b, Time-averaged μBLS intensity versus trigger power (black dots). The red solid line and blue dashed line indicate the probability of the magnonic random number seq… view at source ↗
Figure 3
Figure 3. Figure 3: Working principle of magnonic random number multiplier. a, Electrical schematic of the multiplier circuit integrating two mRNGs. b, Representative pulse sequences showing the reflection signals from RNG1 (black) and RNG2 (red), along with their combined output (blue). c, Statistical voltage distribution obtained from 10,000 pulses, highlighting three distinct operational states. d, 1,000-bit sequences extr… view at source ↗
Figure 4
Figure 4. Figure 4: Scalability of the magnonic random number generator based on waveguides. a, Schematic of the magnonic random bit generator implemented using magnonic waveguides with width of 5 m. b, Electrical probability (red line) and BLS intensity (black dots) as a function of the trigger power for the waveguide based mRNG. c, Representative 1,000-bit sequences obtained at three different trigger powers, as indicated … view at source ↗
read the original abstract

True random number generators (TRNGs) underpin modern cryptography, yet existing implementations face fundamental trade-offs between speed, scalability, and entropy quality. Here, we demonstrate that stochastic switching in the bistable regime of spin-wave dynamics provides a physical entropy source for high-quality random number generation. Our magnonic random number generator (mRNG), based on a lithography-patterned microstrip on yttrium iron garnet (YIG), exploits thermal fluctuations near the nonlinear bistable regime to generate random bitstreams that pass all 15 NIST SP 800-22 statistical tests at rates with 20 Mb/s. We implement a random-bit multiplier using synchronized mRNG units and demonstrate scalability to 200-nm-wide nanoscale waveguides, establishing spin-wave bistability as a viable physical entropy source for integrated random number generation.

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 demonstrates a magnonic random number generator (mRNG) based on a lithography-patterned YIG microstrip that exploits thermal fluctuations near the nonlinear bistable regime of spin-wave dynamics to produce random bitstreams. These bitstreams are reported to pass all 15 NIST SP 800-22 statistical tests at a rate of ~20 Mb/s. The work further implements a random-bit multiplier using synchronized mRNG units and shows scalability to 200-nm-wide nanoscale waveguides, positioning spin-wave bistability as a physical entropy source for integrated TRNGs.

Significance. If the experimental claims are substantiated with full data and analysis, this would establish a new class of magnonic TRNGs that leverage existing YIG fabrication techniques for potentially high-speed, scalable, and integrable randomness sources, offering an alternative to electronic or optical TRNGs with advantages in spintronic compatibility.

major comments (2)
  1. The central experimental claim—that bitstreams generated from stochastic magnonic switching pass NIST tests at 20 Mb/s and constitute true randomness from thermal fluctuations—lacks any description of the measurement setup, raw signal acquisition, thresholding or digitization method, post-processing, or statistical error bars on the reported rate and pass rates. This information is required to evaluate whether the entropy source is unbiased and free of device artifacts.
  2. No quantitative entropy analysis is presented, such as min-entropy estimation (e.g., following NIST SP 800-90B), histograms of switching times, power spectral density of the raw magnonic signal, or autocorrelation functions. Without these, it remains possible that observed NIST compliance arises from hidden periodicities, lithography-induced bias, or amplifier noise rather than purely thermal magnonic bistability.
minor comments (1)
  1. The abstract phrasing 'at rates with 20 Mb/s' is grammatically unclear and should be revised to 'at a rate of 20 Mb/s'.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive feedback and recommendation for major revision. We will revise the manuscript to provide the requested experimental details and quantitative analyses, thereby strengthening the substantiation of our claims regarding the magnonic TRNG.

read point-by-point responses

  1. Referee: The central experimental claim—that bitstreams generated from stochastic magnonic switching pass NIST tests at 20 Mb/s and constitute true randomness from thermal fluctuations—lacks any description of the measurement setup, raw signal acquisition, thresholding or digitization method, post-processing, or statistical error bars on the reported rate and pass rates. This information is required to evaluate whether the entropy source is unbiased and free of device artifacts.

    Authors: We agree that a full description of the experimental methods is necessary for reproducibility and to confirm the absence of artifacts. In the revised manuscript, we will add a dedicated experimental methods section detailing the microwave measurement setup, raw signal acquisition via high-speed oscilloscope, the thresholding and digitization procedure applied to the bistable spin-wave signal, any post-processing steps, and error bars on the bit rate and NIST pass rates obtained from multiple independent runs. This will clarify that the observed randomness stems from thermal fluctuations in the magnonic system. revision: yes

  2. Referee: No quantitative entropy analysis is presented, such as min-entropy estimation (e.g., following NIST SP 800-90B), histograms of switching times, power spectral density of the raw magnonic signal, or autocorrelation functions. Without these, it remains possible that observed NIST compliance arises from hidden periodicities, lithography-induced bias, or amplifier noise rather than purely thermal magnonic bistability.

    Authors: We acknowledge the need for quantitative entropy metrics to rigorously support the physical origin of the randomness. We will incorporate into the revised manuscript min-entropy estimates following NIST SP 800-90B, histograms of switching times to illustrate the stochastic thermal activation, power spectral density of the raw magnonic signal to rule out periodic components, and autocorrelation functions to confirm bit independence. These additions will provide direct evidence against hidden biases or noise sources. revision: yes

Circularity Check

0 steps flagged

No circularity: purely experimental validation of bitstream quality

full rationale

The paper reports an experimental demonstration of random bit generation from thermal fluctuations in a YIG microstrip near the nonlinear bistable regime of spin-wave dynamics. The central claim is that the resulting bitstreams pass all 15 NIST SP 800-22 tests at ~20 Mb/s, with scalability shown via nanoscale waveguides. No derivation chain, equations, or first-principles predictions are present that reduce to fitted inputs, self-definitions, or self-citations by construction. The result is self-contained empirical evidence; any entropy-quality concerns (e.g., missing min-entropy estimators) pertain to evidence strength rather than circularity in a derivation.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

No explicit free parameters, axioms, or invented entities are stated in the abstract; the claim is an experimental demonstration relying on established physics of spin waves and thermal noise.

pith-pipeline@v0.9.0 · 5506 in / 1042 out tokens · 33996 ms · 2026-05-10T02:32:58.026869+00:00 · methodology

discussion (0)

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

Forward citations

Cited by 1 Pith paper

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

  1. Nonlinear frequency shift and bistability of magnon-polarons

    cond-mat.mes-hall 2026-05 unverdicted novelty 7.0

    Nonlinear cross-shift terms from counterpropagating spin waves in a standing SAW cavity produce field-dependent frequency shifts that drive resonance enhancement, broadband scattering, and bistability in magnon-phonon...

Reference graph

Works this paper leans on

45 extracted references · 2 canonical work pages · cited by 1 Pith paper

  1. [1]

    Lanza, A

    M. Lanza, A. Sebastian, W. D. Lu, M. Le Gallo, M. Chang, et al., Memristive technologies for data storage, computation, encryption, and radio-frequency communication, Science 376, 1066 (2022)

    2022

  2. [2]

    W. A. Borders, A. Z. Pervaiz, S. Fukami, K. Y. Camsari, H. Ohno, et al., Integer factorization using stochastic magnetic tunnel junctions. Nature 573, 390 (2019)

    2019

  3. [3]

    K. Kim, S. Bittner, Y. Zeng, S. Guazzotti, O. Hess, et al., Massively parallel ultrafast random bit generation with a chip-scale laser. Science 371, 948 (2021)

    2021

  4. [4]

    Bucci, L

    M. Bucci, L. Germani, R. Luzzi, A. Trifiletti, and M. Varanonuovo, A high-speed oscillator-based truly random number source for cryptographic applications on a smart card IC. IEEE Trans. Computers 52, 403 (2003)

    2003

  5. [5]

    C. S. Petrie, and J. A. Connelly, A noise-based IC random number generator for applications in cryptography. IEEE Trans. Circuits and Systems I 47, 615(2002)

    2002

  6. [6]

    Tokunaga, D

    C. Tokunaga, D. Blaauw, and T. Mudge, True random number generator with a metastability-based quality control. Proc. ISSCC 44, 404 (2007)

    2007

  7. [7]

    A. V. Chumak, V. I. Vasyuchka, A. A. Serga, B. Hillebrands, Magnon spintronics. Nat. Phys. 11, 453- 461 (2015)

    2015

  8. [8]

    Dieny, I

    B. Dieny, I. L. Prejbeanu, K. Garello, P. Gambardella, P. Freitas et al., Opportunities and challenges for spintronics in the microelectronic industry (Topical Review). Nat. Electron. 3, 446-459 (2020)

    2020

  9. [9]

    Flebus, D

    B. Flebus, D. Grundler, B. Rana, Y. Otani, I. Barsukov, et al., The 2024 magnonics roadmap, J. Phys: Condens. Matter 36, 363501 (2024)

    2024

  10. [10]

    Q. Wang, G. Csaba, R. Verba, A. V. Chumak, and P. Pirro, Nanoscale magnonic networks, Phys. Rev. Applied 21, 040503 (2024)

    2024

  11. [11]

    C. Liu, J. Chen, T. Liu, F. Heimbach, H. Yu, et al., Long-distance propagation of short-wavelength spin waves, Nat. Commun. 9, 738 (2018)

    2018

  12. [12]

    H. Qin, R. B. Holländer, L. Flajšman, and S. Van Dijken, Low-Loss Nanoscopic Spin-Wave Guiding in Continuous Yttrium Iron Garnet Films, Nano Lett. 22, 5294 (2022)

    2022

  13. [13]

    Kajiwara, K

    Y. Kajiwara, K. Harii, S. Takahashi, J. Ohe, K. Uchida, et al., Transmission of electrical signal by spin- wave interconversion in a magnetic insulator. Nature 464, 262 (2010)

    2010

  14. [14]

    P. Che, K. Baumgaertl, A. Kúkol’ová, C. Dubs, D. Grundler, Efficient wavelength conversion of exchange magnons below 100 nm by magnetic coplanar waveguides. Nat. Commun. 11, 1445 (2020)

    2020

  15. [15]

    Wintz, V

    S. Wintz, V. Tiberkevich, M. Weigand, J. Raabe, J. Lindner, et al. Magnetic vortex cores as tunable spin-wave emitters. Nat. Nano., 11, 948-953 (2016)

    2016

  16. [16]

    Sluka, T

    V. Sluka, T. Schneider, R. A. Gallardo, A. Kákay, M. Weigand, et al., Emission and propagation of 1D and 2D spin waves with nanoscale wavelengths in anisotropic spin textures. Nat. Nano. 14, 328 (2019)

    2019

  17. [17]

    J. R. Hortensius, D. Afanasiev, M. Matthiesen, R. Leenders, R. Citro, et al., Coherent spin-wave transport in an antiferromagnet, Nat. Phys. 17, 1001 (2021). 12

    2021

  18. [18]

    D. To, A. Rai, J. M. O. Zide, S. Law, J. Q. Xiao, et al., Hybridized magnonic materials for THz frequency applications. Appl. Phys. Lett. 124, 082405 (2024)

    2024

  19. [19]

    Huang, L

    C. Huang, L. Luo, M. Mootz, J. Shang, P. Man, et al., Extreme terahertz magnon multiplication induced by resonant magnetic pulse pairs. Nat. Commun. 15, 3214 (2024)

    2024

  20. [20]

    Körber, C

    L. Körber, C. Heins, T. Hula, J.-V. Kim, S. Thlang, et al., Pattern recognition in reciprocal space with a magnon-scattering reservoir. Nat. Commun. 14, 3954 (2023)

    2023

  21. [21]

    Verba, M

    R. Verba, M. Carpentieri, G. Finocchio, V. Tiberkevich, and A. Slavin, Amplification and stabilization of large-amplitude propagating spin waves by parametric pumping. Appl. Phys. Lett. 112, 042402 (2018)

    2018

  22. [22]

    Krivosik and C

    P. Krivosik and C. E. Patton, Hamiltonian formulation of nonlinear spin-wave dynamics: Theory and applications. Phys. Rev. B 82, 184428 (2010)

    2010

  23. [23]

    Q. Wang, M. Kewenig, M. Schneider, R. Verba, F. Kohl, et al., A magnonic directional coupler for integrated magnonic half-adders. Nat. Electron. 3, 765 (2020)

    2020

  24. [24]

    Lachance-Quirion, S

    D. Lachance-Quirion, S. P. Wolski1, Y. Tabuchi1, S. Kono, K. Usami, Y. Nakamura, Entanglement- based single-shot detection of a single magnon with a superconducting qubit. Science 367, 425 (2020)

    2020

  25. [25]

    H. Yuan, Y. Cao, A. Kamra, R. A. Duine, P. Yan, Quantum magnonics: When magnon spintronics meets quantum information science, Phys. Rep. 965, 1-74 (2022)

    2022

  26. [26]

    Á. Papp, W. Porod, and G. Csaba, Nanoscale neural network using non-linear spin-wave interference, Nat. Commun. 12, 6422 (2021)

    2021

  27. [27]

    Q. Wang, A. V. Chumak, and P. Pirro, Inverse-design magnonic devices, Nat. Commun. 12, 2636 (2021)

    2021

  28. [28]

    Zenbaa, C

    N. Zenbaa, C. Abert, F. Majcen, M. Kerber, R. O. Serha, et al., A universal inverse-design magnonic device. Nat. Electron. 8, 106 (2025)

    2025

  29. [29]

    Stripka, Z

    A. Stripka, Z. Zhang, X. Qi, B. Ursprung, P. Ercius, et al., Intrinsic optical bistability of photon avalanching nanocrystals, Nat. Photon. 19, 212 (2025)

    2025

  30. [30]

    Nozaki, A

    K. Nozaki, A. Shinya, S. Matsuo, Y. Suzaki, T. Segawa, et al., Ultralow-power all-optical RAM based on nanocavities, Nat. Photon. 6, 248 (2012)

    2012

  31. [31]

    Y. Wang, G. Zhang, D. Zhang, T. Li, C.-M Hu, et al., Bistability of Cavity Magnon Polaritons, Phy. Rev. Lett. 120, 057202 (2018)

    2018

  32. [32]

    R. Shen, J. Li, Z. Fan, Y. Wang, and J. Q. You, Mechanical Bistability in Kerr-modified Cavity Magnomechanics, Phys. Rev. Lett. 129, 123601 (2022)

    2022

  33. [33]

    Q. Wang, R. Verba, B. Heinz, M. Schneider, O. Wojewoda, et al. Deeply nonlinear excitation of self- normalized short spin waves, Sci. Adv. 9, eadg4609 (2023)

    2023

  34. [34]

    Y. Li, V. V. Naletov, O. Klein, J. L. Prieto, M. Muñoz, et al., Nutation Spectroscopy of a Nanomagnet Driven into Deeply Nonlinear Ferromagnetic Resonance. Phys. Rev. X 9, 041036 (2019)

    2019

  35. [35]

    Q. Wang, R. Verba, K. Davídková, B. Heinz, S. Tian, et al., All-magnonic repeater based on bistability. Nat. Commun. 15, 7577 (2024)

    2024

  36. [36]

    C. Dubs, O. Surzhenko, R. Thomas, J. Osten, T. Schneider, et al., Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy. Phys. Rev. Materials 4, 024426 (2020). 13

    2020

  37. [37]

    A. A. Serga, A. V. Chumak, and B. Hillebrands, YIG magonics, J. Phys. D: Appl. Phys. 43, 264002 (2010)

    2010

  38. [38]

    Sebastian, K

    T. Sebastian, K. Schultheiss, B. Obry, B. Hillebrands, and H. Schultheiss, Micro-focused Brillouin light scattering: imaging spin waves at the nanoscale. Front. Phys. 3, 55 (2015)

    2015

  39. [39]

    F. Kohl, B. Heinz, M. Wagner, C. Adelmann, F. Ciubotaru, and P. Pirro, Modelling spin -wave interference with electromagnetic leakage in micron-scaled spin-wave transducers, arXiv:2509.24647 (2025)

    work page arXiv 2025

  40. [40]

    L. E. Bassham, A. L. Rukhin, J. Soto, J. R. Nechvatal, M. E. Smid, et al. A statistical test suite for random and pseudorandom number generators for cryptographic applications. NIST, Special Publication (NIST SP) - 800-22 Rev 1a, (2010)

    2010

  41. [41]

    A. V. Chumak, A. A. Serga, M. B. Jungfleisch, R. Neb, D. A. Bozhko, et al., Direct detection of magnon spin transport by the inverse spin Hall effect. Appl. Phys. Lett. 100, 082405 (2012)

    2012

  42. [42]

    Sheng, A

    L. Sheng, A. Duvakina, H. Wang, K. Yamamoto, R. Yuan, et al., Control of spin currents by magnon interference in a canted antiferromagnet, Nat. Phys. 21, 740 (2025)

    2025

  43. [43]

    Collet, O

    M. Collet, O. Gladii, M. Evelt, V. Bessonov, L. Soumah et al., Spin-wave propagation in ultra-thin YIG based waveguides. Appl. Phys. Lett. 110, 092408 (2017)

    2017

  44. [44]

    Bensmann, R

    J. Bensmann, R. Schmidt, K. O. Nikolaev, D. Raskhodchikov, S. Choudhary, et al., Dispersion-tunable low-loss implanted spin-wave waveguides for large magnonic networks. Nat. Mater. 24, 1920 (2025)

    1920

  45. [45]

    Spin + X

    E. Raimondo, A. Grimaldi, V. Tyberkevych, R. Tomasello, A. Giordano, M. Carpentieri, A. Slavin, M. Chiappini, G. Finocchio, arXiv:2510.19648 (2025). Acknowledgements This work was supported from the National Natural Science Foundation of China (Grant No. 12574118). R. V. and D. S. acknowledge support by the NAS of Ukraine via the project of KNU Department...

    work page doi:10.55776/pin1434524 2025