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arxiv: 2605.27301 · v2 · pith:4ACMNNL7new · submitted 2026-05-26 · 🌌 astro-ph.CO · gr-qc· hep-ph· hep-th

Effective Phantom Dark Energy: What Cosmological Reconstruction Does and Does Not Imply

Swagat S. Mishra This is my paper

Pith reviewed 2026-06-29 15:23 UTC · model grok-4.3

classification 🌌 astro-ph.CO gr-qchep-phhep-th
keywords effective dark energyphantom equation of statecosmological reconstructionnull energy conditiondynamical dark energyFLRW cosmologyexpansion history
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The pith

Effective phantom dark energy from cosmological reconstruction does not require fundamental phantom fields or instabilities.

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

The paper shows that dark energy density and equation of state are effective quantities reconstructed from background expansion history under the FLRW metric and standard Friedmann equation with separately conserved matter. Recent hints of phantom or phantom-crossing behavior from data do not force the existence of a microscopic phantom field, ghost instabilities, fundamental null energy condition violation, or a catastrophic future. A sympathetic reader cares because these distinctions prevent jumping from observational trends to claims about fundamental physics that the reconstruction alone cannot support. The clarifications hold regardless of whether future data strengthens or weakens the dynamical dark energy preference. The work defines effective dark energy, offers a kinematic test from expansion history, and reviews non-pathological mechanisms that can produce the effective behavior.

Core claim

Effective phantom behaviour does not necessarily imply the existence of a fundamental phantom field, microscopic ghost instabilities, violation of the null energy condition by the fundamental stress tensor, or a catastrophic cosmic future. These points follow from the definition of effective dark energy in the FLRW framework, the interpretation of phantom and phantom-crossing evolution, a kinematic criterion based directly on the expansion history, and the availability of physical mechanisms such as modified gravity or sector interactions that generate effective phantom behaviour without fundamental pathologies.

What carries the argument

The effective equation-of-state parameter for dark energy reconstructed via the Friedmann equation from the observed expansion history under FLRW assumptions.

If this is right

  • Phantom or phantom-crossing values in the reconstructed equation of state can occur while the fundamental total stress tensor satisfies the null energy condition.
  • No automatic requirement for a big rip or other future singularity arises from effective phantom evolution alone.
  • Mechanisms such as modified gravity or interactions between sectors can generate the observed effective behaviour without introducing fundamental instabilities.
  • A kinematic test applied directly to the scale factor history can identify effective phantom phases independently of any specific model.

Where Pith is reading between the lines

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

  • Model builders should prioritize frameworks that match the effective reconstruction while keeping fundamental fields stable.
  • Distinctions between quintessence and phantom models need explicit separation of effective versus fundamental levels when confronting data.
  • If future surveys confirm dynamical dark energy, the same effective-fundamental split will apply to any proposed explanation.

Load-bearing premise

The distinctions between effective and fundamental quantities remain valid under the standard assumptions of FLRW metric, Friedmann equation, and separately conserved non-relativistic matter at late times.

What would settle it

An explicit demonstration that any reconstruction yielding effective phantom evolution must produce a fundamental null energy condition violation or microscopic ghost that cannot be decoupled from the effective description would settle the claim against it.

Figures

Figures reproduced from arXiv: 2605.27301 by Swagat S. Mishra.

Figure 1
Figure 1. Figure 1: Left panel shows the evolution of DE density relative to its present-epoch value, defined in Eq. (32) for the effective EoS of dark energy in the CPL parametrisation, Eq. (26), for {w0 = −0.7, wa = −0.9}. The dashed black line corresponds to the DE fraction in ΛCDM, namely, fDE = 1. Right panel shows the Hubble parameter corresponding to the phantom-crossing CPL reconstruction (solid green curve), compared… view at source ↗
Figure 2
Figure 2. Figure 2: Left panel schematically shows the quadratic thawing potential, Eq. (49), used to illustrate effective phantom-crossing behaviour on the braneworld. The scalar field remains frozen at early times when H ≫ m, and begins to thaw and roll down the potential once H ≲ m. Right panel shows the corresponding reconstructed effective EoS of dark energy, Eq. (48), for the parameter choice in Eq. (50). The dashed hor… view at source ↗
Figure 3
Figure 3. Figure 3: Shows the phantom-crossing behaviour of the braneworld model with a quadratic thawing [PITH_FULL_IMAGE:figures/full_fig_p022_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Left panel shows the evolution of the reconstructed effective DE density relative to its present-epoch value, fDE(z) = ρ eff DE(z)/ρeff DE0, for the braneworld model with the quadratic thawing potential, Eq. (49). The effective DE density grows with cosmic time during the phantom phase, reaches a maximum near the phantom-divide crossing redshift zph ≃ 0.59, and subsequently decreases at lower redshifts. Ri… view at source ↗
read the original abstract

In observational cosmology, the dark energy density and equation of state are effective quantities reconstructed at the background level under a set of assumptions. These include the FLRW framework, the standard Friedmann equation of General Relativity, and separately conserved non-relativistic matter at late times. Recent analyses involving DESI BAO measurements combined with CMB and supernova data have shown mild preference for dynamical dark energy featuring phantom or phantom-crossing behaviour. While the statistical significance of these trends remains limited, and unresolved systematics or modelling uncertainties may still be important, the resulting discussions have highlighted the need for a clearer interpretation of effective dark energy reconstruction. In particular, effective phantom behaviour does not necessarily imply the existence of a fundamental phantom field, microscopic ghost instabilities, violation of the null energy condition by the fundamental stress tensor, or a catastrophic cosmic future. The purpose of this work is to clarify these distinctions, independently of whether the current observational preference for dynamical dark energy survives future data. We discuss the definition of effective dark energy in cosmology, the interpretation of phantom and phantom-crossing behaviour, introduce a simple kinematic criterion for identifying effective phantom evolution directly from the expansion history, and review physical mechanisms through which effective phantom behaviour may arise without fundamental pathologies. While familiar within the dark energy reconstruction community, these distinctions are often left implicit in broader discussions of dynamical dark energy. We hope that this work will remain useful beyond the present observational situation as a clarification of what observationally reconstructed dark energy does and does not imply.

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

0 major / 2 minor

Summary. The manuscript clarifies the meaning of effective dark energy quantities reconstructed at the background level under the standard assumptions of an FLRW metric, the GR Friedmann equation, and separately conserved non-relativistic matter. It argues that an effective equation-of-state parameter w_DE < -1 or phantom-crossing does not entail a fundamental phantom scalar field, ghost instabilities, null-energy-condition violation by the fundamental stress tensor, or a doomsday scenario. The paper defines effective dark energy, introduces a kinematic criterion based directly on the expansion history H(z) and its derivatives, and reviews existing mechanisms (interactions, modified gravity effective descriptions) that realize effective phantom behavior without fundamental pathologies.

Significance. If the distinctions hold, the paper supplies a timely and useful reference for interpreting recent DESI BAO + CMB + supernova analyses that mildly favor dynamical dark energy with phantom features. Its value lies in making standard but often implicit distinctions explicit without new parameters, fits, or derivations, thereby reducing the risk of over-interpreting effective quantities as fundamental. The work is independent of whether the current observational trend persists and is therefore likely to remain relevant.

minor comments (2)
  1. [Abstract] The abstract states that a 'simple kinematic criterion' is introduced, but the manuscript would be clearer if this criterion were given an explicit equation number and a short dedicated paragraph in the main text rather than being left implicit in the discussion of H(z).
  2. A brief table or bullet list summarizing the reviewed mechanisms (interactions, modified gravity, etc.) and the specific way each evades fundamental pathologies would improve readability for readers outside the reconstruction community.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for their positive assessment of the manuscript, accurate summary of its scope, and recommendation to accept. The report correctly identifies the paper's focus on clarifying the interpretation of effective dark energy quantities without introducing new parameters or derivations.

Circularity Check

0 steps flagged

No significant circularity identified

full rationale

The paper advances no derivations, quantitative predictions, or fitted parameters; its content consists of definitional clarifications, a kinematic criterion defined directly from H(z) and derivatives under explicit FLRW + Friedmann + conserved-matter assumptions, and a review of existing mechanisms. No step reduces by construction to its own inputs, no self-citation is load-bearing for a central claim, and the distinctions drawn are independent of any fitted values or prior author results. The analysis is therefore self-contained with no circular reductions.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is a conceptual clarification and review paper. It relies on standard cosmological framework assumptions already established in the literature and introduces no new free parameters, axioms, or postulated entities.

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Forward citations

Cited by 2 Pith papers

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  2. Late-Time Oscillating Quintessence in Light of DESI

    astro-ph.CO 2026-06 unverdicted novelty 5.0

    A late-onset oscillating quintessence model improves the fit to DESI plus supernova and CMB data by Delta chi squared of about 9 over Lambda CDM, driven by background expansion.

Reference graph

Works this paper leans on

178 extracted references · 164 canonical work pages · cited by 2 Pith papers · 106 internal anchors

  1. [1]

    The Observational case for a low density universe with a nonzero cosmological constant

    J. P. Ostriker and P. J. Steinhardt. “The Observational case for a low density universe with a nonzero cosmological constant”. In:Nature377 (1995), pp. 600–602.doi:10.1038/ 377600a0

    1995

  2. [2]

    Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant

    A. G. Riess et al. “Observational evidence from supernovae for an accelerating universe and a cosmological constant”. In:Astron. J.116 (1998), pp. 1009–1038.doi:10.1086/300499. arXiv:astro-ph/9805201

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/300499 1998

  3. [3]

    Perlmutter, G

    S. Perlmutter et al. “Measurements ofΩandΛfrom 42 High Redshift Supernovae”. In: Astrophys. J.517 (1999), pp. 565–586.doi:10.1086/307221. arXiv:astro-ph/9812133

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/307221 1999

  4. [5]

    Amendola and S

    L. Amendola and S. Tsujikawa.Dark Energy: Theory and Observations. Cambridge Uni- versity Press, Jan. 2015.isbn: 978-1-107-45398-2

    2015

  5. [6]

    Nine YearWilkinson Microwave Anisotropy Probe(WMAP) Observa- tions: Cosmological Parameter Results

    G. Hinshaw et al. “Nine YearWilkinson Microwave Anisotropy Probe(WMAP) Observa- tions: Cosmological Parameter Results”. In:The Astrophysical Journal Supplement Series 208.2 (2013), p. 19.issn: 1538-4365.doi:10.1088/0067- 0049/208/2/19.url:http: //dx.doi.org/10.1088/0067-0049/208/2/19

    work page doi:10.1088/0067- 2013

  6. [7]

    Planck 2018 results. I. Overview and the cosmological legacy of Planck

    N. Aghanim et al. “Planck 2018 results. I. Overview and the cosmological legacy of Planck”. In:Astron. Astrophys.641 (2020), A1.doi:10 . 1051 / 0004 - 6361 / 201833880. arXiv: 1807.06205 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2018

  7. [8]

    The Atacama Cosmology Telescope: DR6 Power Spectra, Likelihoods and $\Lambda$CDM Parameters

    T. Louis et al. “The Atacama Cosmology Telescope: DR6 power spectra, likelihoods and ΛCDM parameters”. In:JCAP11 (2025), p. 062.doi:10.1088/1475-7516/2025/11/062. arXiv:2503.14452 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/1475-7516/2025/11/062 2025

  8. [9]

    SPT-3G D1: CMB temperature and polarization power spectra and cosmology from 2019 and 2020 observations of the SPT-3G Main field

    E. Camphuis et al. “SPT-3G D1: CMB temperature and polarization power spectra and cosmology from 2019 and 2020 observations of the SPT-3G main field”. In:Phys. Rev. D 113.8 (2026), p. 083504.doi:10.1103/7wt3-9v2y. arXiv:2506.20707 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/7wt3-9v2y 2019

  9. [10]

    The Cosmological constant and the theory of elementary particles

    Y. B. Zel’dovich. “The Cosmological constant and the theory of elementary particles”. In: Sov. Phys. Usp.11 (1968), pp. 381–393.doi:10.1007/s10714-008-0624-6

    work page doi:10.1007/s10714-008-0624-6 1968

  10. [11]

    Weinberg, The cosmological constant problem, Review s of Modern Physics, 61, 1 (1989) https://doi.org/10.1103/RevModPhys.61.1

    S. Weinberg. “The Cosmological Constant Problem”. In:Rev. Mod. Phys.61 (1989). Ed. by J.-P. Hsu and D. Fine, pp. 1–23.doi:10.1103/RevModPhys.61.1

    work page doi:10.1103/revmodphys.61.1 1989

  11. [12]

    The Case for a Positive Cosmological Lambda-term

    V. Sahni and A. A. Starobinsky. “The Case for a positive cosmological Lambda term”. In: Int. J. Mod. Phys. D9 (2000), pp. 373–444.doi:10.1142/S0218271800000542. arXiv: astro-ph/9904398. 25

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1142/s0218271800000542 2000

  12. [13]

    Cosmological constant—the weight of the vacuum

    T. Padmanabhan. “Cosmological constant—the weight of the vacuum”. In:Physics Reports 380.5–6 (July 2003), pp. 235–320.issn: 0370-1573.doi:10.1016/s0370-1573(03)00120- 0.url:http://dx.doi.org/10.1016/S0370-1573(03)00120-0

    work page doi:10.1016/s0370-1573(03)00120- 2003

  13. [14]

    The cosmological constant

    R. Bousso. “The cosmological constant”. In:General Relativity and Gravitation40.2–3 (Dec. 2007), pp. 607–637.issn: 1572-9532.doi:10 . 1007 / s10714 - 007 - 0557 - 5.url:http : //dx.doi.org/10.1007/s10714-007-0557-5

    work page doi:10.1007/s10714-007-0557-5 2007

  14. [15]

    Lectures on the Cosmological Constant Problem

    A. Padilla. “Lectures on the Cosmological Constant Problem”. In: (Feb. 2015). arXiv:1502. 05296 [hep-th]

    2015

  15. [16]

    Cosmological Consequences of a Rolling Homogeneous Scalar Field

    B. Ratra and P. J. E. Peebles. “Cosmological Consequences of a Rolling Homogeneous Scalar Field”. In:Phys. Rev. D37 (1988), p. 3406.doi:10.1103/PhysRevD.37.3406

    work page doi:10.1103/physrevd.37.3406 1988

  16. [17]

    Cosmology with Ultra-light Pseudo-Nambu-Goldstone Bosons

    J. A. Frieman et al. “Cosmology with Ultralight Pseudo Nambu-Goldstone Bosons”. In: Phys. Rev. Lett.75 (1995), pp. 2077–2080.doi:10.1103/PhysRevLett.75.2077. arXiv: astro-ph/9505060

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevlett.75.2077 1995

  17. [18]

    The Cosmological Constant and Dark Energy

    P. J. E. Peebles and B. Ratra. “The Cosmological Constant and Dark Energy”. In:Rev. Mod. Phys.75 (2003). Ed. by J.-P. Hsu and D. Fine, pp. 559–606.doi:10.1103/RevModPhys. 75.559. arXiv:astro-ph/0207347

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/revmodphys 2003

  18. [19]

    Cosmology with a Time Variable Cosmological Constant

    P. J. E. Peebles and B. Ratra. “Cosmology with a Time Variable Cosmological Constant”. In:Astrophys. J. Lett.325 (1988), p. L17.doi:10.1086/185100

    work page doi:10.1086/185100 1988

  19. [20]

    Dynamics of dark energy

    Copeland, Edmund J. and Sami, M. and Tsujikawa, Shinji. “Dynamics of dark energy”. In: Int. J. Mod. Phys. D15 (2006), pp. 1753–1936.doi:10.1142/S021827180600942X. arXiv: hep-th/0603057

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1142/s021827180600942x 2006

  20. [22]

    Dark Energy and the Accelerating Universe

    J. A. Frieman, M. S. Turner, and D. Huterer. “Dark Energy and the Accelerating Universe”. In:Annual Review of Astronomy and Astrophysics46.1 (Sept. 2008), pp. 385–432.issn: 1545-4282.doi:10.1146/annurev.astro.46.060407.145243.url:http://dx.doi.org/ 10.1146/annurev.astro.46.060407.145243

    work page doi:10.1146/annurev.astro.46.060407.145243.url:http://dx.doi.org/ 2008

  21. [23]

    Dark Energy and Modified Gravity

    R. Durrer and R. Maartens.Dark Energy and Modified Gravity. 2008. arXiv:0811.4132 [astro-ph].url:https://arxiv.org/abs/0811.4132

    work page internal anchor Pith review Pith/arXiv arXiv 2008

  22. [24]

    Dark Energy

    M. Li et al. “Dark Energy”. In:Communications in Theoretical Physics56.3 (Sept. 2011), pp. 525–604.issn: 0253-6102.doi:10.1088/0253-6102/56/3/24.url:http://dx.doi. org/10.1088/0253-6102/56/3/24

    work page doi:10.1088/0253-6102/56/3/24.url:http://dx.doi 2011

  23. [25]

    Unified cosmic history in modified gravity: From F(R) theory toLorentznon-invariantmodels

    S. Nojiri and S. D. Odintsov. “Unified cosmic history in modified gravity: From F(R) theory toLorentznon-invariantmodels”.In:Physics Reports505.2–4(Aug.2011),pp.59–144.issn: 0370-1573.doi:10.1016/j.physrep.2011.04.001.url:http://dx.doi.org/10.1016/ j.physrep.2011.04.001

    work page doi:10.1016/j.physrep.2011.04.001.url:http://dx.doi.org/10.1016/ 2011

  24. [26]

    Modified gravity and cosmology

    T. Clifton et al. “Modified gravity and cosmology”. In:Physics Reports513.1–3 (Mar. 2012), pp. 1–189.issn: 0370-1573.doi:10.1016/j.physrep.2012.01.001.url:http: //dx.doi.org/10.1016/j.physrep.2012.01.001

    work page doi:10.1016/j.physrep.2012.01.001.url:http: 2012

  25. [27]

    The Limits of Quintessence

    R. R. Caldwell and E. V. Linder. “The Limits of quintessence”. In:Phys. Rev. Lett.95 (2005), p. 141301.doi:10.1103/PhysRevLett.95.141301. arXiv:astro-ph/0505494. 26

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevlett.95.141301 2005

  26. [28]

    Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests

    K. Bamba et al. “Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests”. In:Astrophys. Space Sci.342 (2012), pp. 155–228.doi: 10.1007/s10509-012-1181-8. arXiv:1205.3421 [gr-qc]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1007/s10509-012-1181-8 2012

  27. [29]

    DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations

    A. G. Adame et al. “DESI 2024 VI: cosmological constraints from the measurements of baryon acoustic oscillations”. In:JCAP02 (2025), p. 021.doi:10.1088/1475-7516/2025/ 02/021. arXiv:2404.03002 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/1475-7516/2025/ 2024

  28. [30]

    DESI 2024: reconstructing dark energy using crossing statistics with DESI DR1 BAO data

    R. Calderon et al. “DESI 2024: reconstructing dark energy using crossing statistics with DESI DR1 BAO data”. In:JCAP10 (2024), p. 048.doi:10.1088/1475-7516/2024/10/

    work page doi:10.1088/1475-7516/2024/10/ 2024

  29. [31]

    arXiv:2405.04216 [astro-ph.CO]

    work page arXiv

  30. [32]

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

    M. Abdul Karim et al. “DESI DR2 Results II: Measurements of Baryon Acoustic Oscilla- tions and Cosmological Constraints”. In: (Mar. 2025). arXiv:2503.14738 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2025

  31. [33]

    Planck2018 results: V. CMB power spectra and likelihoods

    N. Aghanim et al. “Planck2018 results: V. CMB power spectra and likelihoods”. In:As- tronomy & Astrophysics641 (Sept. 2020), A5.issn: 1432-0746.doi:10 . 1051 / 0004 - 6361/201936386.url:http://dx.doi.org/10.1051/0004-6361/201936386

    work page doi:10.1051/0004-6361/201936386 2020

  32. [34]

    Union Through UNITY: Cosmology with 2,000 SNe Using a Unified Bayesian Framework

    D. Rubin et al. “Union Through UNITY: Cosmology with 2,000 SNe Using a Unified Bayesian Framework”. In: (Nov. 2023). arXiv:2311.12098 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2023

  33. [35]

    The Pantheon+ Analysis: Cosmological Constraints

    D.Broutetal.“ThePantheon+Analysis:CosmologicalConstraints”.In:Astrophys. J.938.2 (2022), p. 110.doi:10.3847/1538-4357/ac8e04. arXiv:2202.04077 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/ac8e04 2022

  34. [36]

    The Dark Energy Survey: Cosmology Results With ~1500 New High-redshift Type Ia Supernovae Using The Full 5-year Dataset

    T. M. C. Abbott et al. “The Dark Energy Survey: Cosmology Results With ~1500 New High-redshift Type Ia Supernovae Using The DESI 2024 VI: Cosmological Constraints from the Measure-Full 5-year Dataset”. In: (Jan. 2024). arXiv:2401.02929 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2024

  35. [37]

    Ellis, M

    W. J. Wolf, C. García-García, and P. G. Ferreira. “Robustness of dark energy phenomenol- ogy across different parameterizations”. In:JCAP05 (2025), p. 034.doi:10.1088/1475- 7516/2025/05/034. arXiv:2502.04929 [astro-ph.CO]

    work page doi:10.1088/1475- 2025

  36. [39]

    Assessing observational constraints on dark energy

    D. Shlivko and P. J. Steinhardt. “Assessing observational constraints on dark energy”. In: Phys. Lett. B855 (2024), p. 138826.doi:10 . 1016 / j . physletb . 2024 . 138826. arXiv: 2405.03933 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2024

  37. [40]

    Doobservationspreferthawingquintessence?

    G.Payeur,E.McDonough,andR.Brandenberger.“Doobservationspreferthawingquintessence?” In:Phys. Rev. D111.12 (2025), p. 123541.doi:10.1103/bggr-61nr. arXiv:2411.13637 [astro-ph.CO]

    work page doi:10.1103/bggr-61nr 2025

  38. [41]

    The Preference for Evolving Dark Energy from Cosmological Distance Measurements and Possible Signatures in the Growth Rate of Perturbations

    R. E. Keeley et al. “The Preference for Evolving Dark Energy from Cosmological Distance Measurements and Possible Signatures in the Growth Rate of Perturbations”. In: (Feb. 2025). arXiv:2502.12667 [astro-ph.CO]

    work page arXiv 2025

  39. [42]

    Cosmological constraints on curved quintessence

    S. Bhattacharya et al. “Cosmological constraints on curved quintessence”. In:JCAP09 (2024),p.073.doi:10.1088/1475-7516/2024/09/073.arXiv:2405.17396 [astro-ph.CO]

    work page doi:10.1088/1475-7516/2024/09/073.arxiv:2405.17396 2024

  40. [43]

    Nonparametric late-time expansion history reconstruction and implica- tions for the Hubble tension in light of recent DESI and type Ia supernovae data

    J.-Q. Jiang et al. “Nonparametric late-time expansion history reconstruction and implica- tions for the Hubble tension in light of recent DESI and type Ia supernovae data”. In:Phys. Rev. D110.12 (2024), p. 123519.doi:10.1103/PhysRevD.110.123519. arXiv:2408.02365 [astro-ph.CO]. 27

    work page doi:10.1103/physrevd.110.123519 2024

  41. [44]

    Simple quintessence models in light of DESI-BAO observations

    J. M. Cline and V. Muralidharan. “Simple quintessence models in light of DESI-BAO observations”. In:Phys. Rev. D112.6 (2025), p. 063539.doi:10.1103/8z2m-nbv6. arXiv: 2506.13047 [astro-ph.CO]

    work page doi:10.1103/8z2m-nbv6 2025

  42. [45]

    Quintessence and phantoms in light of DESI 2025

    I. D. Gialamas et al. “Quintessence and phantoms in light of DESI 2025”. In: (June 2025). arXiv:2506.21542 [astro-ph.CO]

    work page arXiv 2025

  43. [46]

    Accelerating universes with scaling dark matter

    M. Chevallier and D. Polarski. “Accelerating universes with scaling dark matter”. In:Int. J. Mod. Phys. D10 (2001), pp. 213–224.doi:10.1142/S0218271801000822. arXiv:gr- qc/0009008

    work page doi:10.1142/s0218271801000822 2001

  44. [47]

    Exploring the Expansion History of the Universe

    E. V. Linder. “Exploring the expansion history of the universe”. In:Phys. Rev. Lett.90 (2003), p. 091301.doi:10.1103/PhysRevLett.90.091301. arXiv:astro-ph/0208512

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevlett.90.091301 2003

  45. [48]

    Extended Dark Energy analysis using DESI DR2 BAO measurements

    K. Lodha et al. “Extended Dark Energy analysis using DESI DR2 BAO measurements”. In: (Mar. 2025). arXiv:2503.14743 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2025

  46. [49]

    Popovicet al., arXiv e-prints , arXiv:2506.05471 (2025), arXiv:2506.05471 [astro-ph.CO]

    B. Popovic et al. “A Reassessment of the Pantheon+ and DES 5YR Calibration Uncertain- ties: Dovekie”. In: (June 2025). arXiv:2506.05471 [astro-ph.CO]

    work page arXiv 2025

  47. [50]

    The Dark Energy Survey Supernova Program: A Reanalysis Of Cosmology Results And Evidence For Evolving Dark Energy With An Updated Type Ia Supernova Calibration

    B.Popovicetal.“TheDarkEnergySurveySupernovaProgram:AReanalysisOfCosmology Results And Evidence For Evolving Dark Energy With An Updated Type Ia Supernova Calibration”. In:Mon. Not. Roy. Astron. Soc.548 (2026), stag632.doi:10.1093/mnras/ stag632. arXiv:2511.07517 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/ 2026

  48. [51]

    On DESI’s DR2 exclusion ofΛCDM

    M. Cortês and A. R. Liddle. “On DESI’s DR2 exclusion ofΛCDM”. In: (2025). arXiv: 2504.15336 [astro-ph.CO].url:https://arxiv.org/abs/2504.15336

    work page arXiv 2025

  49. [52]

    Baryon acoustic oscillations from a different angle

    G. Efstathiou. “Baryon acoustic oscillations from a different angle”. In:Mon. Not. Roy. Astron. Soc.540.3 (2025), pp. 2844–2852.doi:10.1093/mnras/staf906. arXiv:2505. 02658 [astro-ph.CO]

    work page doi:10.1093/mnras/staf906 2025

  50. [53]

    Interpreting DESI 2024 BAO: Late-time dynamical dark energy or a local effect?

    I. D. Gialamas et al. “Interpreting DESI 2024 BAO: Late-time dynamical dark energy or a local effect?” In:Phys. Rev. D111.4 (2025), p. 043540.doi:10.1103/PhysRevD.111. 043540. arXiv:2406.07533 [astro-ph.CO]

    work page doi:10.1103/physrevd.111 2024

  51. [54]

    Evolving dark energy or supernovae systematics?

    G. Efstathiou. “Evolving dark energy or supernovae systematics?” In:Mon. Not. Roy. As- tron. Soc.538.2 (2025), pp. 875–882.doi:10.1093/mnras/staf301. arXiv:2408.07175 [astro-ph.CO]

    work page doi:10.1093/mnras/staf301 2025

  52. [55]

    Bayesian and frequentist perspectives agree on dynamical dark energy

    L. Herold and T. Karwal. “Bayesian and frequentist perspectives agree on dynamical dark energy”. In: (June 2025). arXiv:2506.12004 [astro-ph.CO]

    work page arXiv 2025

  53. [56]

    A Bayesian Perspective on Evidence for Evolving Dark Energy

    D. D. Y. Ong, D. Yallup, and W. Handley. “A Bayesian Perspective on Evidence for Evolv- ing Dark Energy”. In: (Nov. 2025). arXiv:2511.10631 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2025

  54. [57]

    The Bayesian view of DESI DR2 with unimpeded: Evidence and tension in a combined analysis with CMB and supernovae across cosmological models

    D. D. Y. Ong, D. Yallup, and W. Handley. “The Bayesian view of DESI DR2 with unim- peded: Evidence and tension in a combined analysis with CMB and supernovae across cosmological models”. In: (Mar. 2026). arXiv:2603.05472 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2026

  55. [58]

    Could We Be Fooled about Phantom Crossing?

    R. E. Keeley, A. Shafieloo, and W. L. Matthewson. “Could We Be Fooled about Phantom Crossing?” In: (June 2025). arXiv:2506.15091 [astro-ph.CO]

    work page arXiv 2025

  56. [59]

    Model-independent consistency tests of DESI DR2 BAO and SN Ia

    H. Woo, W. L. Matthewson, and A. Shafieloo. “Model-independent consistency tests of DESI DR2 BAO and SN Ia”. In: (Apr. 2026). arXiv:2604.19393 [astro-ph.CO]. 28

    work page internal anchor Pith review Pith/arXiv arXiv 2026

  57. [60]

    How much has DESI dark energy evolved since DR1?

    E. Ó. Colgáin et al. “How much has DESI dark energy evolved since DR1?” In:Phys. Dark Univ.52 (2026), p. 102268.doi:10 . 1016 / j . dark . 2026 . 102268. arXiv:2504 . 04417 [astro-ph.CO]

    2026

  58. [61]

    Cosmology-Independent Constraints on the Etherington Relation and SNeIa Absolute Magnitude Evolution from DESI-DR2

    S. Das, S. More, and S. Alam. “Cosmology-Independent Constraints on the Etherington RelationandSNeIaAbsoluteMagnitudeEvolutionfromDESI-DR2”.In:(Apr.2026).arXiv: 2604.02433 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2026

  59. [62]

    The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics

    E. Di Valentino et al. “The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics”. In:Phys. Dark Univ.49 (2025), p. 101965.doi:10.1016/j.dark.2025.101965. arXiv:2504.01669 [astro-ph.CO]

    work page doi:10.1016/j.dark.2025.101965 2025

  60. [63]

    A Phantom Menace? Cosmological consequences of a dark energy component with super-negative equation of state

    R. R. Caldwell. “A Phantom menace?” In:Phys. Lett. B545 (2002), pp. 23–29.doi:10. 1016/S0370-2693(02)02589-3. arXiv:astro-ph/9908168

    work page internal anchor Pith review Pith/arXiv arXiv 2002

  61. [64]

    Null energy condition and superluminal propagation

    S. Dubovsky et al. “Null energy condition and superluminal propagation”. In:JHEP03 (2006), p. 025.doi:10.1088/1126-6708/2006/03/025. arXiv:hep-th/0512260

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/1126-6708/2006/03/025 2006

  62. [65]

    The Null energy condition and instability

    R. V. Buniy, S. D. H. Hsu, and B. M. Murray. “The Null energy condition and instability”. In:Phys. Rev. D74 (2006), p. 063518.doi:10.1103/PhysRevD.74.063518. arXiv:hep- th/0606091

    work page doi:10.1103/physrevd.74.063518 2006

  63. [66]

    Instabilities and the null energy condition

    R. V. Buniy and S. D. H. Hsu. “Instabilities and the null energy condition”. In:Phys. Lett. B632 (2006), pp. 543–546.doi:10.1016/j.physletb.2005.10.075. arXiv:hep- th/0502203

    work page doi:10.1016/j.physletb.2005.10.075 2006

  64. [67]

    Null energy conditions in quantum field theory

    C. J. Fewster and T. A. Roman. “Null energy conditions in quantum field theory”. In: Phys. Rev. D67 (2003). [Erratum: Phys.Rev.D 80, 069903 (2009)], p. 044003.doi:10. 1103/PhysRevD.67.044003. arXiv:gr-qc/0209036

    work page internal anchor Pith review Pith/arXiv arXiv 2003

  65. [68]

    The Classical Singularity Theorems and their Quantum Loopholes

    L. H. Ford. “The Classical singularity theorems and their quantum loop holes”. In:Int. J. Theor. Phys.42 (2003). Ed. by G. Dvali, E. Gunzig, and E. Verdaguer, pp. 1219–1227.doi: 10.1023/A:1025754515197. arXiv:gr-qc/0301045

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1023/a:1025754515197 2003

  66. [69]

    From Satisfying to Violating the Null Energy Condition

    B. Elder, A. Joyce, and J. Khoury. “From Satisfying to Violating the Null Energy Condi- tion”. In:Phys. Rev. D89.4 (2014), p. 044027.doi:10.1103/PhysRevD.89.044027. arXiv: 1311.5889 [hep-th]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevd.89.044027 2014

  67. [70]

    Phantom Energy and Cosmic Doomsday

    R. R. Caldwell, M. Kamionkowski, and N. N. Weinberg. “Phantom energy and cosmic doomsday”. In:Phys. Rev. Lett.91 (2003), p. 071301.doi:10.1103/PhysRevLett.91. 071301. arXiv:astro-ph/0302506

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevlett.91 2003

  68. [71]

    Effective equation of state and energy conditions in phantom/tachyon inflationary cosmology perturbed by quantum effects

    S. Nojiri and S. D. Odintsov. “Effective equation of state and energy conditions in phantom / tachyon inflationary cosmology perturbed by quantum effects”. In:Phys. Lett. B571 (2003), pp. 1–10.doi:10.1016/j.physletb.2003.08.013. arXiv:hep-th/0306212

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1016/j.physletb.2003.08.013 2003

  69. [72]

    Cosmological Dynamics of Phantom Field

    P. Singh, M. Sami, and N. Dadhich. “Cosmological dynamics of phantom field”. In:Phys. Rev. D68 (2003), p. 023522.doi:10.1103/PhysRevD.68.023522. arXiv:hep-th/0305110

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevd.68.023522 2003

  70. [73]

    Phantom cosmologies

    M. P. Dabrowski, T. Stachowiak, and M. Szydlowski. “Phantom cosmologies”. In:Phys. Rev. D68 (2003), p. 103519.doi:10.1103/PhysRevD.68.103519. arXiv:hep-th/0307128

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevd.68.103519 2003

  71. [74]

    Phantom Cosmologies

    V. B. Johri. “Phantom cosmologies”. In:Phys. Rev. D70 (2004), p. 041303.doi:10.1103/ PhysRevD.70.041303. arXiv:astro-ph/0311293

    work page internal anchor Pith review Pith/arXiv arXiv 2004

  72. [75]

    You need not be afraid of phantom energy

    P. F. Gonzalez-Diaz. “You need not be afraid of phantom energy”. In:Phys. Rev. D68 (2003), p. 021303.doi:10.1103/PhysRevD.68.021303. arXiv:astro-ph/0305559. 29

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevd.68.021303 2003

  73. [76]

    Phantom Field and the Fate of Universe

    M. Sami and A. Toporensky. “Phantom field and the fate of universe”. In:Mod. Phys. Lett. A19 (2004), p. 1509.doi:10.1142/S0217732304013921. arXiv:gr-qc/0312009

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1142/s0217732304013921 2004

  74. [77]

    Constructing Phantom Cosmologies from Standard Scalar Field Universes

    L. P. Chimento and R. Lazkoz. “On the link between phantom and standard cosmologies”. In:Phys. Rev. Lett.91 (2003), p. 211301.doi:10.1103/PhysRevLett.91.211301. arXiv: gr-qc/0307111

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevlett.91.211301 2003

  75. [78]

    Sudden Future Singularities

    J. D. Barrow. “Sudden future singularities”. In:Class. Quant. Grav.21 (2004), pp. L79–L82. doi:10.1088/0264-9381/21/11/L03. arXiv:gr-qc/0403084

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0264-9381/21/11/l03 2004

  76. [79]

    The viability of phantom dark energy: A review

    K. J. Ludwick. “The viability of phantom dark energy: A review”. In:Mod. Phys. Lett. A32.28 (2017), p. 1730025.doi:10 . 1142 / S0217732317300257. arXiv:1708 . 06981 [astro-ph.CO]

    2017

  77. [80]

    On big rip singularities

    L. P. Chimento and R. Lazkoz. “On big rip singularities”. In:Mod. Phys. Lett. A19 (2004), pp. 2479–2484.doi:10.1142/S0217732304015646. arXiv:gr-qc/0405020

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1142/s0217732304015646 2004

  78. [81]

    Classical and quantum ghosts

    F. Sbisà. “Classical and quantum ghosts”. In:Eur. J. Phys.36 (2015), p. 015009.doi: 10.1088/0143-0807/36/1/015009. arXiv:1406.4550 [hep-th]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0143-0807/36/1/015009 2015

  79. [83]

    Ghosts in the self-accelerating universe

    K. Koyama. “Ghosts in the self-accelerating universe”. In:Class. Quant. Grav.24.24 (2007), R231–R253.doi:10.1088/0264-9381/24/24/R01. arXiv:0709.2399 [hep-th]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0264-9381/24/24/r01 2007

  80. [84]

    Avoiding Dark Energy with 1/R Modifications of Gravity

    R. P. Woodard. “Avoiding dark energy with 1/r modifications of gravity”. In:Lect. Notes Phys.720 (2007). Ed. by L. Papantonopoulos, pp. 403–433.doi:10.1007/978- 3- 540- 71013-4_14. arXiv:astro-ph/0601672

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1007/978- 2007

Showing first 80 references.