Pith. sign in

REVIEW 4 major objections 4 minor 31 references

Hydride superconductivity: here to stay, or to lead astray and soon go away?

T0 review · 4 major / 4 minor · reviewed 2026-08-10 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read The magnetic evidence for hydride superconductivity is pressure-cell background rather than sample property, this paper argues.

desk verdict Hirsch makes some useful diagnostic points about the 2015 H3S magnetization data, but his central conclusion overreaches an unverified background assumption. read the letter →

arxiv 2501.01466 v2 pith:FGH4OSU3 submitted 2024-12-31 cond-mat.supr-con

J. E. Hirsch This is my paper · ORCID
classification cond-mat.supr-con
keywords hydridesuperconductivitymagnetichysteresisdiamondanvilcellbackgroundsubtractionhigh-pressurerawdatasulfurBCSelectron-phonontheory
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

This paper challenges the recent public declaration that high-pressure hydride superconductivity is genuine. It argues that the magnetization data cited as key evidence are dominated by pressure-cell background, not by the sample. By comparing the 2015 sulfur-hydride magnetization data with the same group's 2022 measurements on identical scales, the author shows inconsistencies in magnitude and shape, and notes that published 'raw' data do not match what was reportedly measured. If correct, the strongest magnetic support for the 203 K superconductivity claim collapses, and the remaining evidence lacks a control experiment.

What carries the argument

The central mechanism is a side-by-side comparison of raw magnetization-versus-field loops from 2015 and 2022, plotted on the same scales before and after linear background subtraction. This comparison shows that the supposedly superconducting loop shape is absent in the later data, that the raw diamagnetic response in 2022 is five times larger than the 2015 response and persists above 200 K, and that a published 'raw' loop does not match the reported measured data. The expected behavior for a superconducting hysteresis loop with flux trapping—magnetization increasing when the field is reduced, per Faraday's law—is used as the criterion that the 2015 published loop fails.

What would settle it

Release the 2015 raw magnetization files and independently subtract an empty-cell background at the same pressure and temperature; if the virgin curve still goes negative and the hysteresis loop retains its flux-trapping shape with magnitude scaling with field, the paper's dismissal of the signal is wrong.

Watch

Extended reading notes

Core claim

The paper's central claim is that the magnetic evidence highlighted by the 2025 manifesto does not provide strong evidence for superconductivity in hydrides. The same group's 2022 measurements show a large diamagnetic background that persists above 200 K and is far too large to come from a superconducting sample, so it must be a property of the pressure cell; this background undermines the claim that the 2015 raw virgin curve going negative is evidence of superconductivity. The paper further demonstrates that the 2022 hysteresis loop crosses its own virgin curve, which is not expected for a superconducting sample, and that published 2022 data were not derived from measured data through scientifically accepted procedures. It concludes that the magnetic case for hydride superconductivity is unsupported and that no control experiment has ever been reported.

Load-bearing premise

The argument assumes that the large diamagnetic background seen in the same group's 2022 measurements at the same temperature and pressure is the same background that contaminated the 2015 signal.

Editorial extensions

If this is right

  • If the magnetic evidence is set aside, the 2015 claim of 203 kelvin superconductivity in sulfur hydride loses its central experimental support.
  • The assertion in the manifesto that hydride superconductivity is overwhelmingly probable is not supported by the data it cites.
  • The absence of control experiments means that no hydride magnetization loop should be accepted as evidence of superconductivity until the pressure-cell background is measured independently.
  • Linear background subtraction is insufficient when the background itself is large, temperature-dependent, and uncharacterized; future measurements must report raw data and background runs.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If this critique is right, other high-pressure hydride magnetization claims, including those for lanthanum hydrides, would need the same raw-data and background scrutiny before being accepted.
  • A concrete testable protocol follows: measure the magnetic response of an emptied or non-superconducting pressure cell under identical pressure, temperature, and field cycles; if a similar hysteresis loop appears, background contamination is confirmed for the whole family of measurements.
  • The author's framing suggests the dispute matters beyond hydrides because it bears on whether conventional electron-phonon theory can predict new superconducting materials; that larger question would be reopened if the magnetic evidence is really an artifact.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

4 major / 4 minor

Summary. The manuscript, authored by J. E. Hirsch, is a commentary that challenges the conclusion of a recently published Comment by Boebinger et al. [1] that hydride superconductivity is genuine. Hirsch argues that the magnetic evidence presented in [1], primarily based on 2015 magnetization data on H3S, is unreliable. He compares raw and background-subtracted hysteresis loops from the 2015 experiments with data from 2022 and concludes that the 2015 raw diamagnetic signal is a background artifact of the pressure cell, rather than evidence of superconductivity. He further claims, citing his own prior analysis, that the published 2022 data were 'manipulated or worse.' The paper ends with broader assertions about the lack of reproducible evidence and the motives of the community.

Significance. The paper raises a legitimate and important issue: the absence of raw data and control experiments in the hydride superconductivity literature is concerning, and the paper usefully documents inconsistencies between the 2015 and 2022 magnetization measurements. If the author's claims were substantiated, the paper would have profound implications for the field. However, the central argument rests on an unverified assumption that the 2022 pressure-cell background is identical to that in 2015, and the accusation of data manipulation is based on an unreviewed self-cited analysis. As a result, the paper's significance is limited by its reliance on unsubstantiated assertions rather than reproducible evidence.

major comments (4)
  1. [Figs. 2 and 3] The argument that the 2015 raw diamagnetic signal (Fig. 1d of Ref. [1]) is a pressure-cell background depends on the unstated assumption that the large diamagnetic background in the 2022 measurements (Fig. 2 right) is identical to the background in the 2015 experiment. This assumption is not justified: the text notes that the 2022 measurements are 'more accurate' and 'significantly improved,' which suggests changes in the sample or apparatus. Without an empty-cell control at the same conditions or a direct comparison of background signals, the possibility remains that the 2015 raw negative virgin curve is a genuine sample property. The author himself acknowledges that no such control exists. This is a load-bearing gap in the reasoning.
  2. [Fig. 5] The claim that the published 2022 data were 'manipulated or worse' is based entirely on Ref. [8], an arXiv preprint by the author and M. van Kampen that has not been peer-reviewed. The manuscript does not reproduce the analysis or present the raw data needed to verify it. A serious accusation of scientific misconduct must be supported by evidence within the paper or by a published correction. Citing an unreviewed preprint is insufficient and makes the claim unverifiable to the reader.
  3. [Introduction] The opening assertion that 'it is overwhelmingly probable that they are wrong' is not supported by the evidence presented. The paper documents apparent discrepancies between figures, but it does not provide a quantitative analysis or rule out alternative explanations, such as differences in sample preparation or measurement conditions. The strength of the conclusion far exceeds what the analysis can justify.
  4. [First and concluding paragraphs] The dismissal of the authors of Ref. [1] as lacking 'scientific validity' because they have not worked on hydrides is an ad hominem argument. Scientific claims should be judged on evidence, not on the credentials or prior field of the claimants. Similarly, the speculation about the community's motives and the implications for BCS theory is outside the scope of the data analysis and is not testable. Statements such as 'None of the myriad of theoretical predictions... have been realized' are not substantiated with a systematic review. These rhetorical elements should be removed or clearly separated from the technical critique.
minor comments (4)
  1. [General] The manuscript contains several typographical errors, including 'magnitute' and 'earler' (in the paragraphs following Fig. 2 and Fig. 6).
  2. [Figs. 1, 2, and 6] The paper does not describe how the data from the original publications were digitized; providing this information would allow readers to verify the comparisons.
  3. [Fig. 5] The references [8] and [9] are not summarized in the text; a reader cannot evaluate the 'manipulated or worse' claim without consulting the external arXiv sources, which is not customary in a self-contained paper.
  4. [Terminology] The term 'raw data' is used in two different senses: as data before background subtraction and as the original digital files from the experiment. This ambiguity should be clarified early in the paper.

Circularity Check

0 steps flagged · score 2.0 of 10

No significant circularity: the critique rests on direct figure comparisons; self-citations are ancillary rather than load-bearing.

full rationale

The paper is a commentary, not a derivation or prediction. Its central conclusion that the 2015 raw negative M(H) signal is a pressure-cell background is an inference from the 2022 measurements, which show a much larger diamagnetic response persisting above 200 K and therefore attributed to the cell. That inference relies on the unstated premise that the 2022 background equals the 2015 background; the paper itself concedes that no control experiment has been reported. This is an evidentiary weakness, not circularity: the conclusion is not defined, fitted, or renamed into the premises. The accusation that the 2022 published data were 'manipulated or worse' invokes Ref. [8], a prior analysis co-authored by the present author; however, that analysis is based on externally reported raw data and is illustrated in the paper's Fig. 5, and the main 2015-vs-2022 argument does not reduce to it. The closing BCS remarks cite the author's own framework but are motivational, not load-bearing for the magnetic-data analysis. No equation-level or construction-level circularity is present; at most there is a minor self-citation, so score 2.

Assumptions & free parameters 0 free parameters · 4 assumptions · 0 invented entities

The paper introduces no new free parameters or entities. Its central argument rests on assumptions about the comparability of 2015 and 2022 experiments, the expected shape of superconducting hysteresis loops, and the reliability of a self-published reanalysis. These are domain assumptions rather than fitted parameters.

assumptions (4)
  • domain assumption The 2022 magnetization data from the same group reveal the background that contaminated the 2015 experiment, so the 2015 raw diamagnetic signal can be attributed to the pressure cell.
    This assumption is used in the discussion of Figs. 2 and 3 to nullify the 2015 raw data signal. If the two cells or samples had different backgrounds, the comparison fails.
  • domain assumption A superconducting sample's hysteresis loop must have certain qualitative features: the virgin curve should not be crossed, ZFC and FC should diverge near Tc, and magnetic moment should scale linearly with applied field.
    These criteria are used to declare the 2015 M(T) and 2022 M(H) data inconsistent with superconductivity. Real inhomogeneous superconductors can deviate from these ideal behaviors.
  • ad hoc to paper The 'actually measured data' reported in Ref. [7] is a faithful record of the experiment, and differences with Ref. [6] imply manipulation by the original authors.
    This underpins the accusation in the Fig. 5 discussion. Ref. [7] is an arXiv preprint by the experimental group that disputes its own published paper, and Ref. [8] (by the current author) interprets it as evidence of manipulation. No independent verification is provided.
  • domain assumption Absence of a reported control experiment counts as evidence against the superconductivity interpretation.
    The conclusion states that no control experiment has ever been reported. While the absence of controls is a legitimate concern, it does not by itself prove that the observed signals are artifacts.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Hydride superconductivity: here to stay, or to lead astray and soon go away?." pith.science (2026). https://pith.science/paper/FGH4OSU3

@misc{pith2026250101466,
  author       = {Pith},
  title        = {Pith review of: Hydride superconductivity: here to stay, or to lead astray and soon go away?},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/FGH4OSU3}},
  note         = {Machine review of arXiv:2501.01466}
}
read the original abstract

In a recent Comment (arXiv:2411.10522, Nat Rev Phys 7, 2 (2025)), fifteen prominent leaders in the field of condensed matter physics declare that hydride superconductivity is real and urge funding agencies to continue to support the field. I question the validity and constructiveness of their argument.

Figures

Figures reproduced from arXiv: 2501.01466 by the authors.

Figure 1
Figure 1. e of Ref. [1] is shown here as Fig. 1b. Ref. [1] describes this figure as follows: “... shows the loop reported in Ref. 6. (Ref. [5] here). Data including the background are shown in the inset. Even before background subtraction, the data for the virgin curve go negative, in low applied fields, offering strong evidence that diamagnetism is observed in the raw data. The simple subtraction of the linear background giv… view at source ↗
Figure 2
Figure 2. FIG. 2: Raw data before background subtraction of 2015 [PITH_FULL_IMAGE:figures/full_fig_p002_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3: Hysteresis loops after background subtraction for [PITH_FULL_IMAGE:figures/full_fig_p002_3.png] view at source ↗
Figures from the paper (2 more)
Figure 5
Figure 5. Figure 5: FIG. 5: Comparison of what was published as depicting [PITH_FULL_IMAGE:figures/full_fig_p003_5.png]
Figure 7
Figure 7. Figure 7: FIG. 7: Same as Fig. 6 after linear background subtraction. [PITH_FULL_IMAGE:figures/full_fig_p003_7.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

31 extracted references · 30 canonical work pages

  1. [1]

    has the main qualitative features expected of a superconducting hysteresis loop in the presence of flux trapping

    present to support their opinion are the hysteresis loops reported in the 2015 Drozdov et al paper that 3 Measured Fig. 3a Published Fig. 3a Magnetic field (mT) FIG. 5: Comparison of what was published as depicting magnetic moment versus magnetic field of sulfur hydride after linear background subtraction in 2022 [6] (left panel) with what was actually me...

    work page 2015

  2. [8]

    Revaluation of the lower critical field in superconducting H$_3$S and LaH$_{10}$ (Nature Comm. 13, 3194, 2022)

    V. S. Minkov, E. F. Talantsev, V. Ksenofontov, S. L. Budko, F. F. Balakirev and M. I. Eremets, “Revaluation of the lower critical field in superconducting H3S and LaH10 (Nature Comm. 13, 3194, 2022)”, arXiv:2408.12675 (2024)

    work page Pith review arXiv 2024

  3. [2]

    Hydride superconductivity: here to stay

    Gregory S. Boebinger, Andrey V. Chubukov, Ian R. Fisher, F. Malte Grosche, Peter J. Hirschfeld, Stephen R. Julian, Bernhard Keimer, Steven A. Kivelson, Andrew P. Mackenzie, Yoshiteru Maeno, Joseph Orenstein, Brad J. Ramshaw, Subir Sachdev, J¨ org Schmalian and Matthias Vojta, “Hydride superconductivity is here to stay”, Nat Rev Phys 7, 2 (2025) and arXiv:...

    work page Pith review arXiv 2025

  4. [3]

    For information on the ‘controversy’ see for example Undark 03.27.2023, Physics World 10/20/2023, Nature News 8/10/2024, PubPeer (2023, 2024)

    work page 2023

  5. [4]

    Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system

    A.P. Drozdov, M. I. Eremets, I. A. Troyan, V. Ksenofontov and S. I. Shylin, “Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system”, Nature 525, 73-76 (2015)

    work page 2015

  6. [5]

    Superconductivity at High Pressure

    M. I. Eremets, “Superconductivity at High Pressure”, In Y. Fei & M. Walter (Eds.), “Static and Dynamic High Pressure Mineral Physics” (pp. 368-386). Cambridge: Cambridge University Press. doi:10.1017/9781108806145.015 (2023)

    work page doi:10.1017/9781108806145.015 2023

  7. [6]

    High-temperature superconductivity in hydrides: experimental evidence and details

    M. I. Eremets, V. S. Minkov, A. P. Drozdov, P. P. Kong, V. Ksenofontov, S. I. Shylin, S. L. Bud’ko, R. Prozorov, F. F. Balakirev, D. Sun, S. Mozaffari and L. Balicas, “High-temperature superconductivity in hydrides: experimental evidence and details”, J Supercond Nov Magn 35, 965 (2022)

    work page 2022

  8. [7]

    Magnetic field screening in hydrogen-rich high-temperature superconductors

    V. S. Minkov, S. L. Budko, F. F. Balakirev , V. B. Prakapenka, S. Chariton, R. J. Husband, H. P. Liermann and M. I. Eremets, “Magnetic field screening in hydrogen-rich high-temperature superconductors”, Nat. Commun. 13, 3194 (2022)

    work page 2022

Show all 31 references
  1. [9]

    Analysis of “Revaluation of the lower critical field in superconducting H3 and LaH10 (Nature Comm. 13, 3194, 2022)

    J. E. Hirsch and M. van Kampen, “Analysis of “Revaluation of the lower critical field in superconducting H3 and LaH10 (Nature Comm. 13, 3194, 2022)” by V. S. Minkov et al”, arXiv:2409.12211 (2024)

    2024 arXiv

  2. [10]

    On the “Author Correction: Magnetic field screening in hydrogen-rich high-temperature superconductors

    J. E. Hirsch, “On the “Author Correction: Magnetic field screening in hydrogen-rich high-temperature superconductors”, Nat Commun 14, 5322 (2023)”, arXiv:2408.09073 (2024) and Nat Commun 15, 8144 (2024)

    2023 arXiv

  3. [11]

    Clear evidence against superconductivity in hydrides under high pressure

    J. E. Hirsch and F. Marsiglio, “Clear evidence against superconductivity in hydrides under high pressure”, Matter and Radiation at Extremes 7, 058401 (2022)

    2022

  4. [12]

    Incompatibility of published ac magnetic susceptibility of a room temperature superconductor with measured raw data

    Hirsch JE and van der Marel D, “Incompatibility of published ac magnetic susceptibility of a room temperature superconductor with measured raw data”, Matter and Radiation at Extremes 7, 048401 (2022)

    2022

  5. [13]

    Are hydrides under high pressure high temperature superconductors?

    J. E. Hirsch, “Are hydrides under high pressure high temperature superconductors?”, National Science Review, nwad174 (2023) and references therein

    2023

  6. [14]

    Hole-doped cuprate high temperature superconductors

    C.W. Chu, L.Z. Deng and B. Lv, “Hole-doped cuprate high temperature superconductors”, Physica C 514, 290 (2015)

    2015

  7. [15]

    Data manipulation and non-availability in hydride superconductivity research

    J. E. Hirsch, “Data manipulation and non-availability in hydride superconductivity research”, Talk presented at the APS March Meeting 2024, RR02.00005, March 8, 2024

    2024

  8. [16]

    Can the public’s trust in science—and scientists—be restored?

    J. E. Hirsch, “Can the public’s trust in science—and scientists—be restored? ”, Talk presented at the APS March Meeting 2024, MM04.00004, March 7, 2024

    2024

  9. [17]

    Room-temperature superconductivity in a carbonaceous sulfur hydride

    E. Snider et al., “Room-temperature superconductivity in a carbonaceous sulfur hydride”, Nature 586, 373 (2020)

    2020

  10. [18]

    Observation of superconductivity in hydrogen sulfide from nuclear resonant scattering

    I. Troyan et al, “Observation of superconductivity in hydrogen sulfide from nuclear resonant scattering”, Science 351, 1303 (2016)

    2016

  11. [19]

    High-temperature superconductivity in sulfur hydride evidenced by alternating-current magnetic susceptibility

    X. Huang et al, “High-temperature superconductivity in sulfur hydride evidenced by alternating-current magnetic susceptibility”, Nat. Sci. Rev. 6, 713 (2019)

    2019

  12. [20]

    Spectroscopic evidence of a new energy scale for superconductivity in H3S

    F. Capitani et al, “Spectroscopic evidence of a new energy scale for superconductivity in H3S”, Nat. Phys. 13, 859 (2017)

    2017

  13. [21]

    Superconductivity in La and Y hydrides: Remaining questions to experiment and theory

    V. Struzhkin et al, “Superconductivity in La and Y hydrides: Remaining questions to experiment and theory”, Matter and Radiation at Extremes 5, 028201 (2020)

    2020

  14. [22]

    Hot Hydride Superconductivity above 550 K

    A. D. Grockowiak et al., “Hot Hydride Superconductivity above 550 K”, Front. Electron. Mater. 2, 837651 (2022)

    2022

  15. [23]

    Imaging the Meissner effect in hydride superconductors using quantum sensors

    P. Bhattacharyya, W. Chen, X. Huang, S. Chatterjee, B. Huang, B. Kobrin, Y. Lyu, T. J. Smart, M. Block, E. Wang, Z. Wang, W. Wu, S. Hsieh, H. Ma, S. Mandyam, B. Chen, E. Davis, Z. M. Geballe, C. Zu, V. Struzhkin, R. Jeanloz, J. E. Moore, T. Cui, G. Galli, B. I. Halperin, C. R....

    2024

  16. [24]

    Magnetic methods in studies of new superconducting hydrides in a diamond anvil cell

    Viktor V. Struzhkin and Ho-kwang Mao, “Magnetic methods in studies of new superconducting hydrides in a diamond anvil cell”, National Science Review 11, nwae005 (2024)

    2024

  17. [25]

    Feasible Route to High-Temperature Ambient- Pressure Hydride Superconductivity

    Kapildeb Dolui, Lewis J. Conway, Christoph Heil, Timothy A. Strobel, Rohit P. Prasankumar , and Chris J. Pickard, “Feasible Route to High-Temperature Ambient- Pressure Hydride Superconductivity”, Phys. Rev. Lett. 132, 166001 (2024) and references therein

    2024

  18. [26]

    Superconducting materials: Judge and 5 jury of BCS-electron–phonon theory

    J. E. Hirsch, “Superconducting materials: Judge and 5 jury of BCS-electron–phonon theory”, Appl. Phys. Lett. 121, 080501 (2022)

    2022

  19. [27]

    The 2021 Room-Temperature Superconductivity Roadmap

    Lilia Boeri, Richard Hennig, Peter Hirschfeld, Gianni Profeta, Antonio Sanna, Eva Zurek, Warren E Pickett, Maximilian Amsler, Ranga Dias, Mikhail I Eremets, Christoph Heil, Russell J Hemley, Hanyu Liu, Yanming Ma, Carlo Pierleoni, Aleksey N Kolmogorov, Nikita Rybin, Dmitry Nov...

    2022

  20. [28]

    Superconductivity Experts Speak Up for Hydride Research

    Matteo Rini “Superconductivity Experts Speak Up for Hydride Research”, Physics 17, 184 (2024)

    2024

  21. [29]

    The search for high-temperature superconductors

    B. T. Matthias, “The search for high-temperature superconductors”, Physics Today Volume 24, Issue 8), pages 23-28 (1971)

    1971

  22. [30]

    Hole superconductivity xOr hot hydride superconductivity

    J. E. Hirsch, “Hole superconductivity xOr hot hydride superconductivity”, J. Appl. Phys. 130, 181102 (2021) and references therein

    2021

  23. [31]

    Superconductivity begins with H

    J. E. Hirsch, “Superconductivity begins with H”, World Scientific, Singapore, 2020

    2020

Pith tools

Reviewed August 10, 2026 · model on record in the stance chip above.