Pith. sign in

REVIEW 3 major objections 4 minor 73 references

Accelerated expansion of the universe model with parametrization of $q(z)$ in $f(R,L_m)$ theory of gravity

T0 review · 3 major / 4 minor · reviewed 2026-08-15 · deepseek-v4-flash

Pith's one-line read This paper claims that a two-parameter deceleration ansatz, integrated to a quadratic Hubble law inside $f(R,L_m)$ modified gravity, accounts for late-time acceleration with a transition at $z_t=0.655$.

desk verdict Model I's Friedmann equations contradict the paper's own field equations: the 3H dot(F_R) term is dropped, so the headline viability claim for Model I is void; the rest is a standard kinematic fit with a circular interpretation. read the letter →

arxiv 2506.15789 v1 pith:IXCM3DVC submitted 2025-06-18 gr-qc

classification gr-qc MSC 83F0583D05 PACS 98.80.-k04.50.Kd
keywords late-timecosmicaccelerationdecelerationparameterf(RL_m)gravityquadraticHubblelawequationofstateenergyconditionscosmographicparameterschronometerdata
open problems Dark Energy
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 tries to establish that a simple kinematic assumption inside $f(R,L_m)$ modified gravity can describe the observed late-time acceleration of the universe. The assumption is a two-parameter deceleration parameter that integrates to the quadratic Hubble law $H(z)=H_0(1+az+bz^2)$. Fitting this expansion history to cosmic-chronometer and Pantheon supernova data gives a present-day deceleration parameter $q_0\approx -0.46$ (CC) or $-0.54$ (CC+Pantheon) and a transition from deceleration to acceleration at $z_t=0.655$. The same expansion history, inserted into two nonlinear $f(R,L_m)$ models, yields positive energy density, negative late-time pressure, an equation-of-state parameter in the quintessence range for one model, violation of the strong energy condition, and a cosmic age near 13 Gyr. If correct, the paper shows that this parametric family is a workable description of the acceleration epoch and that $f(R,L_m)$ gravity can reproduce its main features.

What carries the argument

The load-bearing object is the two-parameter deceleration ansatz, Eq. (16), a rational function of redshift engineered so that integrating $\dot H=-(1+q)H^2$ yields exactly the quadratic Hubble law $H(z)=H_0(1+az+bz^2)$. This quadratic law is the entire expansion history: every derived quantity, including energy density, pressure, equation of state, energy conditions, jerk, snap, and cosmic age, is a function of that quadratic and of the Friedmann equations of the two chosen gravity models. The two $f(R,L_m)$ forms supply the modified Friedmann equations, Eqs. (26)-(27) and Eqs. (29)-(30), that convert the kinematic $H(z)$ into fluid properties and dark-energy behavior.

What would settle it

Fit $H(z)=H_0(1+az+bz^2)$ to the same 31 cosmic-chronometer and 1048 Pantheon points and examine the residuals as a function of redshift. If a nonparametric or higher-order reconstruction of $H(z)$ deviates from the best-fit quadratic by more than the quoted uncertainties, for example by requiring an inflection or a second transition in $q(z)$ away from $z\approx 0.655$, the central claim fails. A direct calculation would be to redo the MCMC with a three-parameter or nonparametric $q(z)$ and compare model selection; the claim requires that the two-parameter quadratic match or beat those alternatives.

Watch

Extended reading notes

Core claim

The central discovery is that the ansatz $q(z)=-1+\frac{(1+z)(a+2bz)}{1+az+bz^2}$ is exactly equivalent, through $H(z)=H_0\,\exp\!\left(\int_0^z \frac{1+q(x)}{1+x}\,dx\right)$, to the normalized Hubble parameter $H(z)/H_0=1+az+bz^2$. With median parameters from MCMC fits, $q(z)$ crosses zero at $z_t=0.655$ for both datasets, so the paper's kinematic core places the present epoch at $q_0<0$, a decelerated matter-dominated past with $q\to\tfrac12$, and a future de Sitter-like phase with $q\to-1$. Feeding this $H(z)$ into the modified Friedmann equations of two $f(R,L_m)$ models, one with nonminimal curvature-matter coupling and one minimal $L_m^\eta$ coupling, gives positive energy density, currently negative pressure, present equation-of-state values $\omega_0\approx -0.28$ and $-0.39$ for Model I and $-0.63$ and $-0.69$ for Model II, and violation of the strong energy condition. The paper therefore asserts that the chosen parametric deceleration form within $f(R,L_m)$ gravity is a viable account of the observed late-time cosmic acceleration.

Load-bearing premise

The load-bearing premise is that the true deceleration history is exactly the two-parameter rational form $q(z)=-1+\frac{(1+z)(a+2bz)}{1+az+bz^2}$, equivalently $H(z)=H_0(1+az+bz^2)$; the paper also assumes $L_m=\rho$ and fixes $\eta=1.03$ by hand, and none of these choices is tested against alternative forms.

Editorial extensions

If this is right

  • The fitted expansion history places the deceleration-to-acceleration transition at $z_t\approx 0.655$ and the present deceleration parameter at $q_0\approx -0.46$ (CC) or $-0.54$ (CC+Pantheon), so the model's kinematic core is compatible with late-time acceleration.
  • Model II, with minimal coupling $f(R,L_m)=R/2+L_m^\eta$, gives a present equation-of-state parameter $\omega_0\approx -0.63$ to $-0.69$, in the quintessence region and closer to dark-energy behavior than Model I.
  • The strong energy condition is violated in both models, as required for accelerated expansion, while the null, weak, and dominant energy conditions remain satisfied.
  • The model returns a cosmic age $t_0\approx 12.8$ to $13.0$ Gyr, and the joint dataset gives a jerk parameter $j_0\approx 0.92$, close to the $\Lambda$CDM value $j_0=1$, while the CC-only jerk deviates more.

Reading between the lines

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

  • Editorial inference: because $H(z)=H_0(1+az+bz^2)$ is fixed purely by the kinematic ansatz before any gravity theory is chosen, the fitted values of $q_0$ and $z_t$ would be unchanged in any modified gravity that adopts the same $q(z)$; the $f(R,L_m)$ analysis recasts that same expansion history in terms of modified fluid densities and pressures rather than independently testing the gravity theory
  • A testable extension the paper does not perform is to treat $\eta$ as a free parameter in the MCMC fit instead of fixing $\eta=1.03$, and to add other cosmological datasets, in order to see whether the gravity-model parameters and the $q(z)$ parameters remain mutually consistent.
  • The two-parameter quadratic $H(z)$ could be checked against nonparametric reconstructions: if $H(z)/H_0$ shows curvature beyond a quadratic, or if the deceleration parameter has a second transition, then the assumption underlying all derived dark-energy results would fail.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

3 major / 4 minor

Summary. The paper studies two f(R,L_m) gravity models, f(R,L_m)=R/2+(1+\eta R)L_m and f(R,L_m)=R/2+L_m^\eta, in a flat FLRW universe with a perfect fluid. It adopts the two-parameter deceleration parameter q(z) of Eq. (16), integrates it to H(z)=H_0(1+a z+b z^2), and fits (H_0,a,b) and the supernova magnitude offset M to 31 cosmic chronometer data points and to a joint CC+Pantheon sample using MCMC. It then derives the energy density, pressure, equation-of-state parameter, energy conditions, cosmographic parameters, and cosmic age for each model. The central claim is that the chosen q(z) parametrization inside f(R,L_m) gravity provides a viable and compelling account of the observed late-time acceleration.

Significance. If all results were correct, the paper would give a compact phenomenological description of late-time acceleration in modified gravity, with posterior constraints on H_0, the transition redshift, and derived dark-energy quantities. The strengths are the transparent parametrization, the use of standard CC and Pantheon datasets, and the fact that the Model II Friedmann equations, Eqs. (29)-(30), are derived correctly from the stated field equations. However, the paper's central viability claim currently rests on Model I results that do not follow from the field equations, on a hand-set coupling \eta=1.03, and on derived quantities that are algebraic consequences of the assumed q(z) rather than dynamical predictions of f(R,L_m). The significance is therefore moderate and conditional on substantial revision.

major comments (3)
  1. [Section 5.1, Eqs. (14)-(15), (26)-(27)] The Friedmann equations for Model I omit the time-derivative terms of F_R. Substituting f=R/2+(1+\eta R)L_m with L_m=\rho into the paper's own Eq. (14) and using R=6(\dot H+2H^2), I obtain 3H^2(1-6\eta\rho)-12\eta\rho\dot H+6H\eta\dot\rho-\rho=0, whereas the printed Eq. (26) is equivalent to 3H^2(1-6\eta\rho)-12\eta\rho\dot H-\rho=0, i.e., the 6H\eta\dot\rho term is missing. Similarly, Eq. (27) drops the 2\eta\ddot\rho+6H\eta\dot\rho terms. Consequently, Eq. (31), Eq. (32), the EoS parameter Eq. (35), and all Model I energy-condition plots in Section 6.4 do not solve the stated field equations; they solve the algebraic system obtained by setting \dot\rho=\ddot\rho=0. This invalidates a major part of the support for the Section 7 conclusion that both models are viable.
  2. [Section 6.2 and Section 5] The value \eta=1.03 is introduced by hand in Section 6.2 with no observational constraint, no error propagation, and no sensitivity analysis. Since \eta is a free parameter in both models and enters Model II as an exponent in Eqs. (29)-(30), the derived energy densities, pressures, EoS parameters, and energy-condition transition redshifts all depend strongly on this arbitrary choice. The paper should constrain \eta jointly with H_0,a,b and M, marginalize over it, or at the minimum show how the derived quantities change with \eta.
  3. [Sections 6.1, 6.5, and 7] The conclusion that the chosen parametrization 'provides a viable and compelling approach' to account for late-time acceleration is overstated relative to what is tested. The fitted quantities q_0, z_t, j_0, s_0, and the derived \omega_0 are deterministic functions of the assumed q(z) family in Eq. (16) and the fitted parameters a and b; they do not test the f(R,L_m) dynamics. A comparison with \LambdaCDM or with alternative q(z) parametrizations, together with a model-selection statistic, would be needed to support the claim that the model is compelling rather than merely consistent with the data.
minor comments (4)
  1. [Section 7 and Table 1] The joint-data best fit is listed as a=0.458 in Table 1, but Section 7 prints a=-0.458 with a minus sign; this typo should be corrected.
  2. [Section 5.2] The text states that setting \eta=0 recovers the conventional Friedmann equations of GR for Model II, but for f=R/2+L_m^\eta the GR limit is \eta=1, not \eta=0; \eta=0 gives R/2+1, which is GR with a cosmological constant rather than the standard Friedmann equations.
  3. [Section 6.4] The sentence saying that the energy-condition results are "consistent with the fulfillment ... of the fundamental energy conditions (EC), namely the Null, Weak, Dominant and Strong EC" is internally contradictory, since the same paragraph states that the Strong EC is violated; it should say all conditions except the SEC are satisfied.
  4. [Table 1] The derived quantities q_0, z_t, j_0, and s_0 are quoted without credible intervals, even though they come from the MCMC chains; the paper should propagate the posterior uncertainties to these quantities.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the q(z) parametrization is an explicitly adopted kinematic prior, and the fitted parameters are empirically constrained rather than renamed as predictions.

full rationale

The paper transparently adopts the deceleration-parameter ansatz in Eq. (16) and integrates it to obtain H(z)=H0(1+az+bz^2) in Eq. (18); it never claims this functional form is derived from f(R,L_m) dynamics. The MCMC analysis fits a and b to the CC and CC+Pantheon data, and the reported q0, zt, j0, s0, and age are estimates computed from the fitted expansion history. The model family allows a>=1 (decelerating present epoch), so the data genuinely select the accelerating branch; the result is therefore an empirical constraint, not a tautology. For Model II, the field equations (29)-(30) are then used to reconstruct rho, p, and omega from the fitted H(z), which is a consistency calculation with independent content. No load-bearing argument rests on a self-citation; citations to [34,60,62] are external or inspirational. A separate correctness concern (not circularity) is that Model I's printed Friedmann equations (26)-(27) appear to omit the 3H dot(F_R) terms that follow from Eq. (14), which would affect the derived Model I density and pressure; this is an error risk, not a circular reduction.

Assumptions & free parameters 5 free parameters · 5 assumptions · 0 invented entities

The analysis depends on an assumed kinematic expansion history (q(z) ansatz) and on the identification L_m=ρ, with the coupling η fixed arbitrarily. These are the main upstream assumptions; the data fitting only constrains H0,a,b,M.

free parameters (5)
  • a = 0.54+0.11/-0.11 (CC), 0.458+0.061/-0.061 (joint)
    Free parameter in the q(z) parametrization, constrained by CC and CC+Pantheon MCMC fits.
  • b = 0.265+0.058/-0.060 (CC), 0.313+0.080/-0.080 (joint)
    Free parameter in the q(z) parametrization, constrained by data.
  • H0 = 67.8+1.7/-1.7 (CC), 68.7+1.9/-1.9 (joint) km/s/Mpc
    Hubble constant, fitted as a free parameter.
  • M = 23.810+0.012/-0.012 (joint)
    Nuisance parameter combining absolute magnitude and H0 in the Pantheon fit.
  • eta = 1.03 (hand-chosen, not fitted)
    Free coupling parameter in both models; the paper does not constrain it and sets it to 1.03 for all plots.
assumptions (5)
  • ad hoc to paper The deceleration parameter takes the assumed form q(z) = -1 + (1+z)(a+2bz)/(1+az+bz^2)
    This ansatz is the core kinematic input; it is not derived from the f(R,L_m) action and is not tested against other forms (Eq. 16).
  • domain assumption The matter Lagrangian equals energy density, L_m = ρ
    Used in Section 5.1 and 5.2 to rewrite the Friedmann equations; this choice is common but not unique and affects all derived ρ,p,EoS.
  • ad hoc to paper The coupling constant η is a fixed constant with value 1.03 for the analysis
    Set by hand for plots; no likelihood or prior is specified for η.
  • domain assumption Flat FLRW metric is the background
    Standard assumption adopted in Section 2, Eq. (9); supported by observations but still restricts the model.
  • standard math The effective gravitational theory respects the f(R,L_m) field equations (5) and (14)-(15)
    The paper relies on the variational principle and Riemannian geometry; this is the theoretical framework, not an ad hoc addition.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Accelerated expansion of the universe model with parametrization of $q(z)$ in $f(R,L_m)$ theory of gravity." pith.science (2026). https://pith.science/paper/IXCM3DVC

@misc{pith2026250615789,
  author       = {Pith},
  title        = {Pith review of: Accelerated expansion of the universe model with parametrization of $q(z)$ in $f(R,L_m)$ theory of gravity},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/IXCM3DVC}},
  note         = {Machine review of arXiv:2506.15789}
}
abstract

In this research work, we explore the late-time accelerated expansion of the universe within the framework of modified gravity, specifically $f(R, L_m)$ theory, by considering two non-linear models: $f(R, L_{m}) = \frac{R}{2}+(1+\eta R) L_{m}$ and $f(R, L_{m}) = \frac{R}{2}+ L_{m}^{\eta}$, where $\eta$ is a free parameter. Adopting a parametric form of the deceleration parameter $q(z)$, we derive a quadratic expression for the normalized Hubble parameter. By use of Bayesian statistical analysis with the $\chi^{2}$-minimization approach, we determine the median values of the model parameters for both the cosmic chronometer (CC) and the joint (CC+Pantheon) dataset. Furthermore, we examine the fundamental cosmological parameters: energy density, pressure, the equation of state (EoS) parameter and energy conditions. The cosmographic parameters are thoroughly analyzed and the present age of the universe is estimated based on this model.

Figures

Figures reproduced from arXiv: 2506.15789 by the authors.

Figure 1
Figure 1. The best-fit H(z) curve with z for the proposed model in comparison to the ΛCDM model. 4.2 The Pantheon dataset We employ the Pantheon compilation, which consists of 1048 Type Ia supernovae (SNIa) data points cov￾ering the redshift range 0.01 < z < 2.26, as reported in Ref. [51]. This comprehensive dataset is assembled from various high-quality surveys, including CfA1–CfA4 series [52, 53], the Pan-STARRS1 Medium Dee… view at source ↗
Figure 2
Figure 2. 1D and 2D marginalized contours map for H0, a, b and M using the Joint CC+Pantheon dataset. 7 [PITH_FULL_IMAGE:figures/full_fig_p007_2.png] view at source ↗
Figure 3
Figure 3. The deceleration parameter(q) versus z. derived using the Hubble parameter and its derivative with respect to time. ρ(z) = 3H 2 0 (1+az+bz2 ) 2 H2 0 (1+az+bz2 )[18η(1+az+bz2 )−12η(1+z)(a+2bz)] +1 Model(I) (31) p(z) = − H0E[6ηH 3 0 (2E −(1+z)(a+2bz))(3E 2 −4(1+z)(a+2bz)E)] [PITH_FULL_IMAGE:figures/full_fig_p009_3.png] view at source ↗
Figures from the paper (7 more)
Figure 5
Figure 5. Figure 5: Pressure(p) versus z for model(I). − −        [PITH_FULL_IMAGE:figures/full_fig_p010_5.png]
Figure 6
Figure 6. Figure 6: Energy density(ρ) versus z for model(II). − −        − [PITH_FULL_IMAGE:figures/full_fig_p010_6.png]
Figure 8
Figure 8. Figure 8: EoS parameter (ω) versus z for model(I). − −        − − [PITH_FULL_IMAGE:figures/full_fig_p011_8.png]
Figure 10
Figure 10. Figure 10: For Model(I): (ρ + p) versus z. − −     [PITH_FULL_IMAGE:figures/full_fig_p012_10.png]
Figure 12
Figure 12. Figure 12: For Model(I): (ρ +3p) versus z. − −        [PITH_FULL_IMAGE:figures/full_fig_p013_12.png]
Figure 15
Figure 15. Figure 15: For Model(II): (ρ − p) versus z. 6.5 Cosmographic parameters The evolution of the universe can be characterized through kinematic parameters like jerk (j) and snap (s), which are derived from the scale factor and its successive time derivatives, offering a purely geom…
Figure 16
Figure 16. Figure 16: Variation of jerk parameter (j) versus z. − −        − − − [PITH_FULL_IMAGE:figures/full_fig_p014_16.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

73 extracted references · 9 canonical work pages

  1. [1]

    A. G. Riess, A. V . Filippenko, P . Challis, A. Clocchiatti, A. Diercks, et al., Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant, Astronomical Journal 116 (3) (1998) 1009–1038. doi:https://doi.org/10.1086/300499

  2. [2]

    Perlmutter, G

    S. Perlmutter, G. Aldering, G. Goldhaber, R. A. Knop, P . N ugent, et al., Measurements of Ω and Λ from 42 High-Redshift Supernovae, Astrophysical Journal 5 17 (2) (1999) 565–586. doi:https://doi.org/10.1086/307221

  3. [3]

    Aghanim, Y

    N. Aghanim, Y . Akrami, M. Ashdown, J. Aumont, C. Baccigal upi, et al., Planck 2018 15 results. VI. Cosmological parameters, Astronomy and Astro physics 641 (2020) A6. doi:https://doi.org/10.1051/0004-6361/201833910

  4. [4]

    Weinberg, The cosmological constant problem, Review s of modern physics 61 (1) (1989) 1

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

  5. [5]

    Di V alentino, O

    E. Di V alentino, O. Mena, S. Pan, L. Visinelli, W. Y ang, et al., In the realm of the hub- ble tension—a review of solutions, Classical and Quantum Gr avity 38 (15) (2021) 153001. doi:10.1088/1361-6382/ac086d

  6. [6]

    S. M. Carroll, The cosmological constant, Living review s in relativity 4 (1) (2001) 1–56. doi:https://doi.org/10.12942/lrr-2001-1

  7. [7]

    H. A. Buchdahl, Non-linear lagrangians and cosmologica l theory, Monthly Notices of the Royal Astro- nomical Society 150 (1) (1970) 1–8. doi:https://doi.org/10.1093/mnras/150.1.1

  8. [8]

    Harko, F

    T. Harko, F. S. Lobo, S. Nojiri, S. D. Odintsov, f (r, t) gra vity, Physical Re- view D—Particles, Fields, Gravitation, and Cosmology 84 (2 ) (2011) 024020. doi:https://doi.org/10.1103/PhysRevD.84.024020

Show all 73 references
  1. [9]

    Nojiri, S

    S. Nojiri, S. D. Odintsov, Unified cosmic history in modifi ed gravity: from f (r) theory to lorentz non-invariant models, Physics Reports 50 5 (2-4) (2011) 59–144. doi:https://doi.org/10.1016/j.physrep.2011.04.001

  2. [10]

    Nojiri, S

    S. Nojiri, S. D. Odintsov, V . K. Oikonomou, Modified grav ity theories on a nut- shell: Inflation, bounce and late-time evolution, Physics R eports 692 (2017) 1–104. doi:https://doi.org/10.1016/j.physrep.2017.06.001

  3. [11]

    Capozziello, V

    S. Capozziello, V . Cardone, H. Farajollahi, A. Ravanpa k, Cosmography in f (t) gravity, Physical Review D—Particles, Fields, Gravitation, and Cos mology 84 (4) (2011) 043527. doi:https://doi.org/10.1103/PhysRevD.84.043527

  4. [12]

    Capozziello, R

    S. Capozziello, R. D’Agostino, O. Luongo, Extended gra vity cosmogra- phy, International Journal of Modern Physics D 28 (10) (2019 ) 1930016. doi:https://doi.org/10.1142/S0218271819300167

  5. [13]

    A. R. Lalke, G. P . Singh, A. Singh, Late-time accelerati on from ekpyrotic bounce in f (q, t) gravity, International Journal of Geometric Methods in Mod ern Physics 20 (08) (2023) 2350131. doi:https://doi.org/10.1142/S0219887823501311

  6. [14]

    Kotambkar, G

    S. Kotambkar, G. P . Singh, R. Kelkar, B. K. Bishi, Anisot ropic bianchi type i cosmological models with generalized chaplygin gas and dynamical gravitational and cosmological constants, Communications in Theoretical Physics 67 (2) (2017) 222. doi:10.1088/0253-6102/67/2/222

  7. [15]

    G. P . Singh, K. Desikan, A new class of cosmological mode ls in lyra geometry, Pramana 49 (1997) 205–212. doi:https://doi.org/10.1007/BF02845856

  8. [16]

    Singh, S

    A. Singh, S. Mandal, R. Chaubey, R. Raushan, Observatio nal constraints on the expansion scalar and shear relation in the locally rotationally symmetric bianc hi i model, Physics of the Dark Universe 47 (2025) 101798. doi:https://doi.org/10.1016/j.dark.2024.101798

  9. [17]

    M. B. V arela, O. Bertolami, Is cosmological data sugges ting a nonminimal cou- pling between matter and gravity?, Physics of the Dark Unive rse 48 (2025) 101861. doi:https://doi.org/10.1016/j.dark.2025.101861

  10. [18]

    Singh, G

    A. Singh, G. P . Singh, A. Pradhan, Cosmic dynamics and qu alitative study of rastall model 16 with spatial curvature, International Journal of Modern Ph ysics A 37 (16) (2022) 2250104. doi:https://doi.org/10.1142/S0217751X22501044

  11. [19]

    Hulke, G

    N. Hulke, G. P . Singh, B. K. Bishi, A. Singh, V ariable cha plygin gas cosmolo- gies in f (r, t) gravity with particle creation, New Astronom y 77 (2020) 101357. doi:https://doi.org/10.1016/j.newast.2020.101357

  12. [20]

    G. P . Singh, R. Garg, A. Singh, A generalized lambda cdm m odel with parameterized hubble parameter in particle creation, viscous and f (r) model framework, Int ernational Journal of Geometric Methods in Modern Physics (2025) 2550111 doi:https://doi.org/10.1142/S0219887825501117

  13. [21]

    Bamba, S

    K. Bamba, S. D. Odintsov, L. Sebastiani, S. Zerbini, Fin ite-time future singularities in modified gauss– bonnet and f(r, g) gravity and singularity avoidance, The Eu ropean Physical Journal C 67 (2010) 295–

  14. [22]

    R. Garg, G. P . Singh, A. Singh, Cosmic dynamics and obser vational constraints in f (q) gravity with affine equation of state, arXiv preprint arXiv:2503.03212 ( 2025)

  15. [23]

    G. P . Singh, N. Hulke, A. Singh, Thermodynamical and obs ervational aspects of cosmological model with linear equation of state, International Journal of Geo metric Methods in Modern Physics 15 (08) (2018) 1850129. doi:https://doi.org/10.1142/S0219887818501293

  16. [24]

    Harko, F

    T. Harko, F. S. N. Lobo, f ( r, lm) gravity, The European Physical Journal C 70 (2010) 373–379 . doi:https://doi.org/10.1140/epjc/s10052-010-1467-3

  17. [25]

    Faraoni, Cosmology in scalar tensor gravity (2004)

    V . Faraoni, Cosmology in scalar tensor gravity (2004). doi:https://doi.org/10.1007/978-1-4020-1989

  18. [26]

    Zhang, Behavior of f (r) gravity in the solar system, g alaxies, and clusters, Physical Review D 76 (2) (2007) 024007

    P . Zhang, Behavior of f (r) gravity in the solar system, g alaxies, and clusters, Physical Review D 76 (2) (2007) 024007. doi:https://doi.org/10.1103/PhysRevD.76.024007

  19. [27]

    Bertolami, J

    O. Bertolami, J. P´ aramos, S. G. Turyshev, General theo ry of relativity: Will it survive the next decade?, in: Lasers, Clocks and Drag-Free Control: Exploration of Re lativistic Gravity in Space, Springer, 2008, pp. 27–74. doi:https://doi.org/10.48550/arXiv.gr-qc/0602016

  20. [28]

    Rahaman, S

    F. Rahaman, S. Ray, M. Kalam, M. Sarker, Do solar system t ests permit higher dimensional general relativity?, Int. J. Theor. Phys. 48 (3 ) (2009) 3124–3138. doi:https://doi.org/10.1007/s10773-009-0110-2

  21. [29]

    Nojiri, S

    S. Nojiri, S. D. Odintsov, Gravity assisted dark energy dominance and cosmic acceleration, Physics Letters B 599 (3-4) (2004) 137–142. doi:https://doi.org/10.1016/j.physletb.2004.08.045

  22. [30]

    Allemandi, A

    G. Allemandi, A. Borowiec, M. Francaviglia, S. D. Odint sov, Dark energy dominance and cosmic acceleration in first-order formalism, Physical Review D 72 (6) (2005) 063505. doi:https://doi.org/10.1103/PhysRevD.72.063505

  23. [31]

    Manna, A

    G. Manna, A. Panda, A. Karmakar, S. Ray, M. R. Islam, f (r, lx)-gravity in the context of dark en- ergy with power law expansion and energy conditions, Chines e Physics C 47 (2) (2023) 025101. doi:https://doi.org/10.1088/1674-1137/ac9fbe

  24. [32]

    F. S. N. Lobo, T. Harko, Extended f (R, Lm) theories of gra vity, 2015. doi:https://doi.org/10.1142/9789814623995_0110

  25. [33]

    Myrzakulov, O

    Y . Myrzakulov, O. Donmez, G. D. A. Yildiz, E. G¨ udekli, S. Muminov, et al., Linear redshift parametriza- tion of deceleration parameter in f (r, lm) gravity, Physics of the Dark Universe 45 (2024) 101545. doi:https://doi.org/10.1016/j.dark.2024.101545. 17

  26. [34]

    Myrzakulova, M

    S. Myrzakulova, M. Koussour, N. Myrzakulov, Investiga ting the dark energy phenomenon in f (r, lm) cosmological models with observational constraints, Phys ics of the Dark Universe 43 (2024) 101399. doi:https://doi.org/10.1016/j.dark.2023.101399

  27. [35]

    Kavya, V

    N. Kavya, V . V enkatesha, S. Mandal, P . K. Sahoo, Constra ining anisotropic cosmo- logical model in f (r, lm) gravity, Physics of the Dark Univer se 38 (2022) 101126. doi:https://doi.org/10.1016/j.dark.2022.101126

  28. [36]

    Y . K. Devi, S. Narawade, B. Mishra, Constraining parame ters for the accelerat- ing universe in f (r, lm) gravity, Physics of the Dark Univers e 46 (2024) 101640. doi:https://doi.org/10.1016/j.dark.2024.101640

  29. [37]

    R. Garg, T. Chowdhury, G. P . Singh, F. Rahaman, Cosmolog ical model with gong-zong parametrization in f (r, l m) gravity, arXiv preprint arXiv:2501.08161 (2025)

  30. [38]

    R. Garg, G. P . Singh, A. R. Lalke, S. Ray, Cosmological mo del with linear equa- tion of state parameter in f (r, lm) gravity, Physics Letters A 525 (2024) 129937. doi:https://doi.org/10.1016/j.physleta.2024.129937

  31. [39]

    Pradhan, D

    A. Pradhan, D. C. Maurya, G. K. Goswami, A. Beesham, Mode ling transit dark energy in f(r,lm)- gravity, International Journal of Geometric Methods in Mod ern Physics 20 (06) (2023) 2350105. doi:https://doi.org/10.1142/S0219887823501050

  32. [40]

    Ryden, Introduction to cosmology addison wesley san francisco (2003)

    B. Ryden, Introduction to cosmology addison wesley san francisco (2003)

  33. [41]

    Banerjee, S

    N. Banerjee, S. Das, Acceleration of the universe with a simple trigono- metric potential, General Relativity and Gravitation 37 (2 005) 1695–1703. doi:https://doi.org/10.1007/s10714-005-0152-6

  34. [42]

    Cunha, J

    J. Cunha, J. A. S. d. Lima, Transition redshift: new kine matic constraints from su- pernovae, Monthly Notices of the Royal Astronomical Societ y 390 (1) (2008) 210–217. doi:https://doi.org/10.1111/j.1365-2966.2008.13640. x

  35. [43]

    Foreman-Mackey, D

    D. Foreman-Mackey, D. W. Hogg, D. Lang, J. Goodman, emce e: the mcmc hammer, Publications of the Astronomical Society of the Pacific 125 (925) (2013) 306. doi:10.1086/670067

  36. [44]

    Simon, L

    J. Simon, L. V erde, R. Jimenez, Constraints on the redsh ift dependence of the dark energy potential, Physical Review D 71 (12) (2005 ) 123001. doi:https://doi.org/10.1103/PhysRevD.71.123001

  37. [45]

    G. S. Sharov, V . O. V asiliev, How predictions of cosmolo gical models de- pend on hubble parameter data sets, arXiv preprint arXiv:18 07.07323 (2018). doi:https://doi.org/10.26456/mmg/2018-611

  38. [46]

    Stern, R

    D. Stern, R. Jimenez, L. V erde, M. Kamionkowski, S. A. St anford, Cosmic chronometers: constraining the equation of state of dark energy. i: H (z) measurements, J ournal of Cosmology and Astroparticle Physics 2010 (02) (2010) 008. doi:10.1088/1475-7516/2010/02/008

  39. [47]

    M. Moresco, Raising the bar: new constraints on the hubb le parameter with cosmic chronome- ters at z 2, Monthly Notices of the Royal Astronomical Societ y: Letters 450 (1) (2015) L16–L20. doi:https://doi.org/10.1093/mnrasl/slv037

  40. [48]

    Jimenez, A

    R. Jimenez, A. Loeb, Constraining cosmological parame ters based on relative galaxy ages, The Astro- physical Journal 573 (1) (2002) 37. doi:https://doi.org/10.1086/340549

  41. [49]

    Mandal, A

    S. Mandal, A. Singh, R. Chaubey, Late-time constraints on barotropic fluid cosmology, Physics Letters A 519 (2024) 129714. doi:https://doi.org/10.1016/j.physleta.2024.129714. 18

  42. [50]

    Mandal, A

    S. Mandal, A. Singh, R. Chaubey, Cosmic evolution of hol ographic dark energy in f (q, t) gravity, International Journal of Geometric Methods in Mod ern Physics 20 (05) (2023) 2350084. doi:https://doi.org/10.1142/S0219887823500846

  43. [51]

    D. M. Scolnic, D. Jones, A. Rest, Y . Pan, R. Chornock, et a l., The complete light- curve sample of spectroscopically confirmed sne ia from pan- starrs1 and cosmological con- straints from the combined pantheon sample, The Astrophysi cal Journal 859 (2) (2018) 101. doi:https:/...

  44. [52]

    A. G. Riess, R. P . Kirshner, B. P . Schmidt, S. Jha, P . Chal lis, et al., BVRI light curves for 22 type ia supernovae, The Astronomical Journal 1 17 (2) (1999) 707. doi:https://doi.org/10.1086/300738

  45. [53]

    Hicken, W

    M. Hicken, W. M. Wood-V asey, S. Blondin, P . Challis, S. J ha, et al., Improved dark energy constraints from 100 new cfa supernova type ia light curves, The Astrophy sical Journal 700 (2) (2009) 1097. doi:https://doi.org/10.1088/0004-637X/700/2/1097

  46. [54]

    M. Sako, B. Bassett, A. C. Becker, P . J. Brown, H. Campbel l, et al., The data release of the sloan digital sky survey-ii supernova survey, Publications of the Astronomical Society of the Pacific 130 (988) (2018) 064002. doi:10.1088/1538-3873/aab4e0

  47. [55]

    J. Guy, M. Sullivan, A. Conley, N. Regnault, P . Astier, et al., The supernova legacy survey 3-year sample: Type ia supernovae photometric distances and cosmological constraints, Astronomy & Astrophysics 523 (2010) A7. doi:https://doi.org/10.1051/0004-6361/201014468

  48. [56]

    Contreras, M

    C. Contreras, M. Hamuy, M. Phillips, G. Folatelli, N. B. Suntzeff, et al., The carnegie supernova project: first photometry data release of low-redshift type ia supernovae, The Astronomical Journal 139 (2) (2010)

  49. [57]

    S. D. Odintsov, V . Oikonomou, A. Timoshkin, E. N. Sarida kis, R. Myrzakulov, Cosmo- logical fluids with logarithmic equation of state, Annals of Physics 398 (2018) 238–253. doi:https://doi.org/10.1016/j.aop.2018.09.015

  50. [58]

    Asvesta, L

    K. Asvesta, L. Kazantzidis, L. Perivolaropoulos, C. G. Tsagas, Observational constraints on the deceler- ation parameter in a tilted universe, Monthly Notices of the Royal Astronomical Society 513 (2) (2022) 2394–2406. doi:https://doi.org/10.1093/mnras/stac922

  51. [59]

    Harko, F

    T. Harko, F. S. N. Lobo, Generalized curvature-matter c ouplings in modified gravity, Galaxies 2 (3) (2014) 410–465. doi:https://doi.org/10.3390/galaxies2030410

  52. [60]

    R. V . Lobato, G. Carvalho, C. Bertulani, Neutron stars i n f (r, l m) f (r, l m) gravity with realistic equations of state: joint-constrains with g w170817, massive pulsars, and the psr j0030+ 0451 mass-radius from nicer data, The European Physi cal Journal C 81 (2021) 1–7. d...

  53. [61]

    Harko, F

    T. Harko, F. S. Lobo, J. P . Mimoso, D. Pav´ on, Gravitatio nal induced particle production through a nonminimal curvature–matter coupling, The European Phys ical Journal C 75 (2015) 1–15. doi:https://doi.org/10.1140/epjc/s10052-015-3620-5

  54. [62]

    A. Bose, G. Sardar, S. Chakraborty, Analytic solutions and observational support: A study of f (r, t) gravity with f (r, t)= r+ h (t), Physics of the Dark Un iverse 37 (2022) 101087. doi:https://doi.org/10.1016/j.dark.2022.101087

  55. [63]

    Visser, Energy conditions in the epoch of galaxy form ation, Science 276 (5309) (1997) 88–90

    M. Visser, Energy conditions in the epoch of galaxy form ation, Science 276 (5309) (1997) 88–90. doi:https://doi.org/10.1126/science.276.5309.88. 19

  56. [64]

    A. R. Lalke, G. P . Singh, A. Singh, Cosmic dynamics with l ate-time constraints on the para- metric deceleration parameter model, The European Physica l Journal Plus 139 (3) (2024) 288. doi:https://doi.org/10.1140/epjp/s13360-024-05091-5

  57. [65]

    Singh, R

    A. Singh, R. Raushan, R. Chaubey, S. Mandal, K. C. Mishra , Lagrangian formulation and implications of barotropic fluid cosmologies, International Journal of G eometric Methods in Modern Physics 19 (07) (2022) 2250107. doi:https://doi.org/10.1142/S0219887822501079

  58. [66]

    Singh, Homogeneous and anisotropic cosmologies wit h affine eos: a dynam- ical system perspective, The European Physical Journal C 83 (8) (2023) 696

    A. Singh, Homogeneous and anisotropic cosmologies wit h affine eos: a dynam- ical system perspective, The European Physical Journal C 83 (8) (2023) 696. doi:https://doi.org/10.1140/epjc/s10052-023-11879-z

  59. [67]

    Weinberg, Cosmology oxford university press (2008)

    S. Weinberg, Cosmology oxford university press (2008)

  60. [68]

    Mukherjee, N

    A. Mukherjee, N. Banerjee, Parametric reconstruction of the cosmological jerk from diverse observational data sets, Physical Review D 93 ( 4) (2016) 043002. doi:https://doi.org/10.1103/PhysRevD.93.043002

  61. [69]

    Visser, Jerk, snap and the cosmological equation of s tate, Classical and Quantum Gravity 21 (11) (2004) 2603

    M. Visser, Jerk, snap and the cosmological equation of s tate, Classical and Quantum Gravity 21 (11) (2004) 2603. doi:https://doi.org/10.1088/0264-9381/21/11/006

  62. [70]

    F. Y . Wang, Z. G. Dai, S. Qi, Probing the cosmographic par ameters to distinguish between dark energy and modified gravity models, Astronomy & Astroph ysics 507 (1) (2009) 53–59. doi:https://doi.org/10.1051/0004-6361/200911998

  63. [71]

    M.-L. Tong, Y . Zhang, Cosmic age, statefinder, and om dia gnostics in the decaying vacuum cosmology, Physical Review D 80 (2) (2009) 0 23503. doi:https://doi.org/10.1103/PhysRevD.80.023503. 20

  64. [310]

    doi:https://doi.org/10.1140/epjc/s10052-010-1292-8

  65. [519]

    doi:10.1088/0004-6256/139/2/519

Pith tools

Reviewed August 15, 2026 · model on record in the stance chip above.