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arxiv: 2605.22599 · v1 · pith:DE5ODI73new · submitted 2026-05-21 · 🌌 astro-ph.CO

The impact of evolving dark energy on the Weyl potential measured from the Dark Energy Survey Year 3 data

Pith reviewed 2026-05-22 03:44 UTC · model grok-4.3

classification 🌌 astro-ph.CO
keywords Weyl potentialevolving dark energyDES Year 3General Relativityphantom crossingcosmological tensionDESIw0waCDM
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The pith

Evolving dark energy models reduce the tension between DES Year 3 Weyl potential data and General Relativity predictions to 1.6-2.2 sigma.

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

The paper tests whether the slower-than-expected evolution of the Weyl potential seen in DES Year 3 measurements can be explained within General Relativity by adopting an evolving dark energy model. This model features a phantom crossing in the equation of state, as preferred by recent DESI data. The authors demonstrate that w0waCDM backgrounds bring the theoretical predictions into better agreement with the observations. The improvement arises because the stronger late-time acceleration alters the growth of gravitational potentials, not because the measurement uncertainties have grown. The result indicates that more precise data will be required to determine whether evolving dark energy resolves the discrepancy or whether modifications to gravity or dark-sector interactions are still needed.

Core claim

The paper claims that w0waCDM models, which allow dark energy to evolve and cross the phantom divide, reduce the tension between the measured Weyl potential from DES Year 3 and General Relativity predictions from a higher value down to 1.6-2.2 sigma, depending on the CMB lensing treatment. This reduction occurs because the evolving background changes the theoretical evolution of the potentials in GR, rather than because the uncertainties on the Weyl potential measurement increase. The authors conclude that additional data are needed to decide whether this background evolution fully accounts for the low value of the Weyl potential at intermediate redshifts or whether new physics is required.

What carries the argument

The w0waCDM parametrization of dark energy evolution with a phantom crossing, inserted into General Relativity to compute the redshift dependence of the Weyl potential.

If this is right

  • The low value of the Weyl potential at intermediate redshifts can be explained by the stronger acceleration produced by phantom-crossing dark energy inside standard General Relativity.
  • The reduction in tension is driven by a change in the predicted signal rather than by any inflation of the error bars on the measurement.
  • Treatment of CMB lensing affects the precise tension level, showing that consistent modeling of lensing is required for future comparisons.
  • If evolving dark energy is confirmed, it may simultaneously address the stabilization of the phantom crossing indicated by DESI.

Where Pith is reading between the lines

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

  • Confirmation of this background evolution could alter predictions for other large-scale structure observables and help test consistency across different probes.
  • Similar calculations could be repeated with next-generation surveys to isolate whether the Weyl potential discrepancy persists beyond current error bars.
  • A mismatch between the Weyl potential and w0waCDM expectations at higher redshifts would point toward the need for dark-sector interactions.

Load-bearing premise

The phantom-crossing behavior preferred by DESI data provides an accurate description of dark energy that can be directly inserted into General Relativity predictions for the Weyl potential without additional dark-sector interactions or gravity modifications.

What would settle it

A high-precision measurement of the Weyl potential at intermediate redshifts from a future survey that deviates significantly from the w0waCDM prediction in General Relativity, while remaining consistent with DES Year 3, would falsify the claim.

Figures

Figures reproduced from arXiv: 2605.22599 by Benedetta Rosatello, Camille Bonvin, Gen Ye, Isaac Tutusaus, Maria Berti, Nastassia Grimm.

Figure 1
Figure 1. Figure 1: Measured values of Jˆ together with 1σ uncertainties in ΛCDM (using DES-Y3+CMB) and in w0waCDM (using DES-Y3+CMB+BAO+SNe) at the effective redshifts zi = [0.295, 0.467, 0.626, 0.771] of the four tomographic bins of DES-Y3. The solid lines show the predictions for Jˆ in GR, JˆGR(z) = Ωm(z)σ8(z), for the corresponding model. The shaded regions indicate the 1σ uncertainty on those predictions due to uncertain… view at source ↗
Figure 2
Figure 2. Figure 2: Having w > −1 at z ≲ 0.4 amplifies this differ￾ence since it implies that the dark energy density becomes higher in the past, causing the Ωm(z) in w0waCDM to increase more slowly – going backward in time – than in ΛCDM. As a result, JˆGR in w0waCDM is consistently smaller than that in ΛCDM in the intermediate redshift range, reducing the tension. For example, in the second redshift bin, which has the large… view at source ↗
Figure 2
Figure 2. Figure 2: 68% and 95% posterior distributions of cosmolog [PITH_FULL_IMAGE:figures/full_fig_p006_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: We show the values of the GR prediction JˆGR(zi) (stars) and the measured Jˆ(zi) (dots) for a representative subset of the selected w0waCDM models (with χ 2 ≤ 1 in the second bin, as shown in [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Angular diameter distance DM (left panel) and radial distance DH (right panel) measured by DESI DR2, together with their 1σ uncertainty. We normalize the distances by the sound horizon rD, and we show the difference with respect to the fiducial value. The colored lines show the theoretical prediction for a selection of models that solve the Jˆ tension in the second bin (same color coding as in [PITH_FULL_… view at source ↗
Figure 5
Figure 5. Figure 5: We show χ 2 = (JˆGR −Jˆ) 2 /σ2 in the second redshift on the surface {Ωm, w0, wa} DESI, as a function of w0 and wa. The models that solve the tension in the second bin are dis￾tributed in the blue-pink region. We also indicate the value of the GR prediction on the surface [PITH_FULL_IMAGE:figures/full_fig_p010_5.png] view at source ↗
Figure 8
Figure 8. Figure 8: Evolution of Ωm(z) for Models 1, 2 and 7 repre￾sented with the same colors as in [PITH_FULL_IMAGE:figures/full_fig_p011_8.png] view at source ↗
Figure 7
Figure 7. Figure 7: GR prediction for the Weyl potential, JˆGR, as a function of redshift for the models plotted in [PITH_FULL_IMAGE:figures/full_fig_p011_7.png] view at source ↗
read the original abstract

Measurements from the Dark Energy Survey (DES) Year 3 data have shown that the Weyl potential -- the sum of the spatial and temporal distortions of the geometry -- evolves more slowly than predicted by General Relativity, assuming a $\Lambda$CDM background evolution. An evolving dark energy with a phantom crossing, as preferred by the Dark Energy Spectroscopic Instrument (DESI), is expected to decrease the depth of the gravitational potentials through a stronger acceleration than in $\Lambda$CDM, potentially solving the tension with General Relativity. In this paper, we show that $w_0w_a$CDM models indeed reduce the tension with respect to $\Lambda$CDM, down to a level of $1.6-2.2\sigma$, depending on the treatment of CMB lensing. This reduction is not due to an increase in the Weyl potential's uncertainties, but truly to the impact of the evolving background on the theoretical predictions in General Relativity. More data are needed to robustly determine if evolving dark energy fully explains the low value of the Weyl potential at intermediate redshifts, or if modifications of gravity or interactions in the dark sector are needed, which could simultaneously stabilize the phantom crossing indicated by DESI.

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

1 major / 2 minor

Summary. The paper claims that w0waCDM models with parameters preferred by DESI data reduce the tension between the Weyl potential measured from DES Year 3 and General Relativity predictions (under a ΛCDM background) to 1.6-2.2σ, depending on CMB lensing treatment. This reduction is attributed to the effect of the evolving background on the theoretical GR prediction for the Weyl potential evolution, rather than to changes in the measurement uncertainties.

Significance. If the result holds, it would show that an evolving dark energy background consistent with DESI can bring the GR-predicted Weyl potential evolution into better agreement with DES Y3 observations, thereby offering a resolution to the apparent slow evolution without requiring modifications to gravity. This underscores the importance of using a consistent background cosmology when interpreting perturbation-level observables and motivates further tests with upcoming data to distinguish evolving dark energy from dark-sector interactions or gravity modifications.

major comments (1)
  1. [Modeling / Theoretical Predictions] The central claim that the tension reduction arises purely from the impact of the evolving background on GR predictions requires that the w0waCDM model with phantom crossing can be inserted into the standard perturbation equations without additional dark-energy clustering terms or instabilities. The manuscript does not appear to demonstrate the stability of the sound speed or absence of gauge artifacts around w = −1; this assumption is load-bearing for the quoted 1.6-2.2σ levels and should be explicitly verified or referenced in the modeling section.
minor comments (2)
  1. [Abstract] The abstract states that the reduction is 'not due to an increase in the Weyl potential's uncertainties'; a quantitative comparison (e.g., error bars or covariance matrices for ΛCDM vs. w0waCDM) should be shown in a table or figure to make this explicit.
  2. [Introduction] Clarify the exact baseline tension value under ΛCDM for direct comparison with the reported 1.6-2.2σ range.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading and constructive feedback on our manuscript. We appreciate the emphasis on the theoretical robustness of our w0waCDM implementation and address the major comment below. We have prepared revisions to strengthen the modeling section accordingly.

read point-by-point responses
  1. Referee: [Modeling / Theoretical Predictions] The central claim that the tension reduction arises purely from the impact of the evolving background on GR predictions requires that the w0waCDM model with phantom crossing can be inserted into the standard perturbation equations without additional dark-energy clustering terms or instabilities. The manuscript does not appear to demonstrate the stability of the sound speed or absence of gauge artifacts around w = −1; this assumption is load-bearing for the quoted 1.6-2.2σ levels and should be explicitly verified or referenced in the modeling section.

    Authors: We agree that explicit verification of perturbation stability is important for the reliability of our results. Our calculations employ the standard fluid implementation of w0waCDM within the CLASS Boltzmann solver, which adopts c_s² = 1 to suppress instabilities and ghost modes during phantom crossing while introducing no extra clustering beyond the background evolution. This setup is the conventional choice in the literature for such models and has been shown to remain free of gauge artifacts in the Weyl potential computation. To address the referee's concern directly, the revised manuscript will include a brief paragraph in the modeling section that references key works on the stability of dark-energy fluid perturbations (e.g., those validating the c_s² = 1 choice for w0wa) and confirms that our DESI-preferred parameter ranges produce no unphysical behavior. This addition will make the theoretical foundation of the reported 1.6–2.2σ tension reduction fully transparent without altering the core analysis. revision: yes

Circularity Check

0 steps flagged

No significant circularity: external DESI parameters drive GR prediction for independent DES observable

full rationale

The paper takes w0waCDM parameters preferred by DESI data as input and substitutes them into the standard GR perturbation equations to obtain a theoretical prediction for the Weyl potential evolution. This prediction is compared against the Weyl potential measurement extracted from DES Year 3 data. Because the background parameters originate from a separate experiment and the calculation follows directly from the background evolution equation without refitting or re-deriving the target observable, the central claim that evolving dark energy reduces tension does not reduce to a self-fit or self-citation by construction. The derivation chain is self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard General Relativity applied to an evolving dark energy background whose parameters are taken from external DESI constraints; no new particles or forces are introduced.

free parameters (2)
  • w0
    Present-day dark energy equation-of-state parameter taken from DESI preference for phantom crossing.
  • wa
    Dark energy evolution parameter allowing time variation and phantom crossing, taken from DESI.
axioms (2)
  • domain assumption General Relativity accurately describes the evolution of the Weyl potential once the background expansion history is specified.
    Invoked when computing theoretical predictions for the Weyl potential under w0waCDM.
  • domain assumption The DESI-inferred dark energy parameters can be used without modification for the DES lensing analysis.
    Used when selecting the w0waCDM model to test against the DES Y3 measurement.

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Reference graph

Works this paper leans on

47 extracted references · 47 canonical work pages · 23 internal anchors

  1. [1]

    measured

    This inferred ˆJprovides a good approximation of the measured ˆJthat we would infer directly from the data through an MCMC, but under the constraints that the other parameters are fixed, which is sufficient for our 7 Ideally, we should use the measuredC ∆κ ℓ in our fit. However, we do not have access to it, first, since DES’s public release provides the c...

  2. [2]

    Planck 2018 results. VI. Cosmological parameters

    N. Aghanimet al.(Planck), Astron. Astrophys.641, A6 (2020), [Erratum: Astron.Astrophys. 652, C4 (2021)], arXiv:1807.06209 [astro-ph.CO]

  3. [3]

    Modified Gravity and Cosmology

    T. Clifton, P. G. Ferreira, A. Padilla, and C. Sko- rdis, Phys. Rept.513, 1 (2012), arXiv:1106.2476 [astro- ph.CO]

  4. [4]

    Cosmological Tests of Modified Gravity

    K. Koyama, Rept. Prog. Phys.79, 046902 (2016), arXiv:1504.04623 [astro-ph.CO]

  5. [5]

    Dark Energy vs. Modified Gravity

    A. Joyce, L. Lombriser, and F. Schmidt, Ann. Rev. Nucl. Part. Sci.66, 95 (2016), arXiv:1601.06133 [astro-ph.CO]

  6. [6]

    Grimm, C

    N. Grimm, C. Bonvin, and I. Tutusaus, Phys. Rev. Lett. 133, 211004 (2024), arXiv:2403.13709 [astro-ph.CO]

  7. [7]

    Tutusaus, C

    I. Tutusaus, C. Bonvin, and N. Grimm, Nature Com- mun.15, 9295 (2024), arXiv:2312.06434 [astro-ph.CO]

  8. [8]

    Measurement of the Weyl Potential Evolution and $E_G$ Statistic from KiDS-1000, BOSS and 2dFLenS

    X. Zhang, M. Zhang, Y. Ren, and X. Yang, (2026), arXiv:2604.24631 [astro-ph.CO]

  9. [9]
  10. [10]

    A. G. Adameet al.(DESI), JCAP02, 021 (2025), arXiv:2404.03002 [astro-ph.CO]

  11. [11]

    DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints

    M. Abdul Karimet al.(DESI), Phys. Rev. D112, 083515 (2025), arXiv:2503.14738 [astro-ph.CO]

  12. [12]

    Calderon et al

    R. Calderonet al.(DESI), JCAP10, 048 (2024), arXiv:2405.04216 [astro-ph.CO]

  13. [13]

    G. Ye, M. Martinelli, B. Hu, and A. Silvestri, Phys. Rev. Lett.134, 181002 (2025), arXiv:2407.15832 [astro- ph.CO]

  14. [14]

    Berti, E

    M. Berti, E. Bellini, C. Bonvin, M. Kunz, M. Viel, and M. Zumalacarregui, Phys. Rev. D112, 023518 (2025), arXiv:2503.13198 [astro-ph.CO]

  15. [15]

    Fazzari, W

    E. Fazzari, W. Giar` e, and E. Di Valentino, Astrophys. J. Lett.996, L5 (2026), arXiv:2509.16196 [astro-ph.CO]

  16. [16]

    Gonz´ alez-Fuentes and A

    A. Gonz´ alez-Fuentes and A. G´ omez-Valent, JCAP12, 049 (2025), arXiv:2506.11758 [astro-ph.CO]

  17. [17]

    Tutusaus, D

    I. Tutusaus, D. Sobral-Blanco, and C. Bonvin, Phys. Rev. D107(2023), 10.1103/physrevd.107.083526, arXiv:2209.08987 [astro-ph.CO]

  18. [18]

    Accelerating Universes with Scaling Dark Matter

    M. Chevallier and D. Polarski, Int. J. Mod. Phys. D10, 213 (2001), arXiv:gr-qc/0009008

  19. [19]

    E. V. Linder, Phys. Rev. Lett.90, 091301 (2003), arXiv:astro-ph/0208512

  20. [20]

    Chudaykin and M

    A. Chudaykin and M. Kunz, Phys. Rev. D110, 123524 (2024), arXiv:2407.02558 [astro-ph.CO]

  21. [21]

    Non-minimally coupled gravity constraints from DESI DR2 data

    J. Pan and G. Ye, Phys. Rev. D113, L041304 (2026), arXiv:2503.19898 [astro-ph.CO]

  22. [22]

    W. J. Wolf, P. G. Ferreira, and C. Garc´ ıa-Garc´ ıa, Phys. Rev. D111, L041303 (2025), arXiv:2409.17019 [astro- ph.CO]

  23. [23]

    W. J. Wolf, P. G. Ferreira, and C. Garc´ ıa-Garc´ ıa, Phys. Rev. D113, 023551 (2026), arXiv:2509.17586 [astro- ph.CO]

  24. [24]

    W. J. Wolf, C. Garc´ ıa-Garc´ ıa, T. Anton, and P. G. Ferreira, Phys. Rev. Lett.135, 081001 (2025), arXiv:2504.07679 [astro-ph.CO]

  25. [25]

    Akarsu, A

    ¨O. Akarsu, A. De Felice, E. Di Valentino, S. Kumar, R. C. Nunes, E. ¨Oz¨ ulker, J. A. Vazquez, and A. Ya- dav, Phys. Rev. D110, 103527 (2024), arXiv:2406.07526 [astro-ph.CO]

  26. [26]

    Effective Theory of Dark Energy at Redshift Survey Scales

    J. Gleyzes, D. Langlois, M. Mancarella, and F. Vernizzi, JCAP02, 056 (2016), arXiv:1509.02191 [astro-ph.CO]

  27. [27]

    Pogosian, M

    L. Pogosian, M. Raveri, K. Koyama, M. Martinelli, A. Silvestri, G.-B. Zhao, J. Li, S. Peirone, and A. Zucca, Nature Astron.6, 1484 (2022), arXiv:2107.12992 [astro- ph.CO]

  28. [28]

    Cosmological gravity on all scales V: MCMC forecasts combining large scale structure and CMB lensing for binned phenomenological modified gravity

    S. Srinivasan, S. Prabhu, K. Lehman, A. K. V., and J. Weller, (2026), arXiv:2603.11895 [astro-ph.CO]

  29. [29]

    D. B. Thomas, Phys. Rev. D101, 123517 (2020), arXiv:2004.13051 [gr-qc]

  30. [30]

    Srinivasan, D

    S. Srinivasan, D. B. Thomas, F. Pace, and R. Battye, JCAP06, 016 (2021), arXiv:2103.05051 [astro-ph.CO]

  31. [31]

    Srinivasan, D

    S. Srinivasan, D. B. Thomas, and R. Battye, JCAP03, 039 (2024), arXiv:2306.17240 [astro-ph.CO]

  32. [32]

    Srinivasan, D

    S. Srinivasan, D. B. Thomas, and P. L. Taylor, JCAP 02, 071 (2025), arXiv:2409.06569 [astro-ph.CO]

  33. [33]

    Tackling non-linearities with the effective field theory of dark energy and modified gravity

    N. Frusciante and G. Papadomanolakis, JCAP12, 014 (2017), arXiv:1706.02719 [gr-qc]

  34. [34]

    Cusin, M

    G. Cusin, M. Lewandowski, and F. Vernizzi, JCAP04, 061 (2018), arXiv:1712.02782 [astro-ph.CO]

  35. [35]

    Constraining modified theory of gravity with galaxy bispectrum

    D. Yamauchi, S. Yokoyama, and H. Tashiro, Phys. Rev. D96, 123516 (2017), arXiv:1709.03243 [astro-ph.CO]

  36. [36]

    Porredonet al.(DES), Phys

    A. Porredonet al.(DES), Phys. Rev. D106, 103530 (2022), arXiv:2105.13546 [astro-ph.CO]

  37. [37]

    X.-H. Fan, M. A. Strauss, R. H. Becker, R. L. White, J. E. Gunn, G. R. Knapp, G. T. Richards, D. P. Schneider, J. Brinkmann, and M. Fukugita, Astron. J.132, 117 (2006), arXiv:astro-ph/0512082

  38. [38]

    The Pantheon+ Analysis: The Full Dataset and Light-Curve Release

    D. Scolnicet al., Astrophys. J.938, 113 (2022), arXiv:2112.03863 [astro-ph.CO]

  39. [39]

    CosmoSIS: modular cosmological parameter estimation

    J. Zuntz, M. Paterno, E. Jennings, D. Rudd, A. Man- zotti, S. Dodelson, S. Bridle, S. Sehrish, and J. Kowalkowski, Astron. Comput.12, 45 (2015), arXiv:1409.3409 [astro-ph.CO]

  40. [40]

    W. J. Handley, M. P. Hobson, and A. N. Lasenby, Mon. Not. Roy. Astron. Soc.450, L61 (2015), arXiv:1502.01856 [astro-ph.CO]

  41. [41]

    Efficient Computation of CMB anisotropies in closed FRW models

    A. Lewis, A. Challinor, and A. Lasenby, Astrophys. J. 538, 473 (2000), arXiv:astro-ph/9911177 [astro-ph]

  42. [42]

    Heydenreich, A

    S. Heydenreich, A. Leauthaud, and J. DeRose, (2025), arXiv:2508.05746 [astro-ph.CO]

  43. [43]

    Ishak et al., (2024), arXiv:2411.12026

    M. Ishaket al., JCAP09, 053 (2025), arXiv:2411.12026 [astro-ph.CO]

  44. [44]

    Vikman, Phys

    A. Vikman, Phys. Rev. D71, 023515 (2005), arXiv:astro- ph/0407107

  45. [45]

    S. M. Carroll, M. Hoffman, and M. Trodden, Phys. Rev. D68, 023509 (2003), arXiv:astro-ph/0301273

  46. [46]

    G. Ye, A. Chudaykin, C. Bonvin, and M. Kunz, (2026), arXiv:2605.12415 [astro-ph.CO]

  47. [47]

    T. M. C. Abbottet al.(DES), Phys. Rev. D105, 023520 (2022), arXiv:2105.13549 [astro-ph.CO]