Is There Evidence for Dark Energy Evolution?

Ding, Xuheng; Biesiada, Marek; Cao, Shuo; Li, Zheng‐Xiang; Zhu, Zong-Hong

doi:10.1088/2041-8205/803/2/l22

Cited by 85 publications

(86 citation statements)

References 43 publications

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“…Next, we have used the 29 data points of H (z) [71][72][73][74][75][76][77][78][79] in the redshift range 0.07 ≤ z ≤ 2.34. These values are presented in Table 1.…”

Section: Observational Constraints On ω φ (Z)mentioning

confidence: 99%

Study of non-canonical scalar field model using various parametrizations of dark energy equation of state

Mamon

Das

2015

Eur. Phys. J. C

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In this present work, we try to build up a cosmological model using a non-canonical scalar field within the framework of a spatially flat FRW space-time. In this context, we have considered four different parametrizations of the equation of state parameter of the non-canonical scalar field. Under this scenario, analytical solutions for various cosmological parameters have been found out. It has been found that the deceleration parameter shows a smooth transition from a positive value to some negative value which indicates that the universe was undergoing an early deceleration followed by late time acceleration which is essential for the structure formation of the universe. With these four parametrizations, the future evolution of the models are also discussed. It has been found that one of the models (Generalized Chaplygin gas model, GCG) mimics the concordance CDM in the near future, whereas two other models (CPL and JBP) diverge due to future singularity. Finally, we have studied these theoretical models with the latest datasets from SN Ia + H (z) + BAO/CMB.

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“…Next, we have used the 29 data points of H (z) [71][72][73][74][75][76][77][78][79] in the redshift range 0.07 ≤ z ≤ 2.34. These values are presented in Table 1.…”

Section: Observational Constraints On ω φ (Z)mentioning

confidence: 99%

Study of non-canonical scalar field model using various parametrizations of dark energy equation of state

Mamon

Das

2015

Eur. Phys. J. C

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“…This result is intriguing, especially when contrasted with the analysis of the same data using the Om(z i , z j ) diagnostic (Ding et al 2015;Zheng et al 2016). These earlier works used an improper statistical analysis, and did not include the R h = ct universe in their comparisons, principally because the Om(z i , z j ) diagnostic cannot be applied to it directly.…”

Section: O N C L U S I O Nmentioning

confidence: 88%

“…using Type Ia SNe; see Wei et al 2017, and references cited therein). In addition, we shall demonstrate in this paper that the statistics of two-point diagnostics has been used improperly in earlier applications, including those of Ding et al (2015) and Zheng et al (2016). Specifically, we shall show that previous applications of two-point diagnostics have overestimated the confidence level of their results, thereby overstating the tension between, for example, the measured H(z) values and predictions by CDM.…”

Section: Introductionmentioning

confidence: 84%

“…the approach used by Ding et al (2015) and Zheng et al (2016) in their analyses. This determination of the error is inaccurate, however, and significantly underestimates the true error in the mean of the two-point diagnostic.…”

Section: O D E L C O M Pa R I S O N Smentioning

confidence: 99%

“…Previously, Ding et al (2015) and Zheng et al (2016) m , applicable to several cosmological models. In these analyses, the two-point diagnostic was calculated based on the m parameter in CDM, such that it should be consistent with zero if CDM were the correct model.…”

Section: Introductionmentioning

confidence: 99%

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Analysing H(z) data using two-point diagnostics

Leaf

Melia

2017

Monthly Notices of the Royal Astronomical Society

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Measurements of the Hubble constant H(z) are increasingly being used to test the expansion rate predicted by various cosmological models. But the recent application of two-point diagnostics, such as Om(z i , z j ) and Omh 2 (z i , z j ), has produced considerable tension between CDM's predictions and several observations, with other models faring even worse. Part of this problem is attributable to the continued mixing of truly model-independent measurements using the cosmic-chronometer approach, and model-dependent data extracted from baryon acoustic oscillations. In this paper, we advance the use of two-point diagnostics beyond their current status, and introduce new variations, which we call h(z i , z j ), that are more useful for model comparisons. But we restrict our analysis exclusively to cosmic-chronometer data, which are truly model independent. Even for these measurements, however, we confirm the conclusions drawn by earlier workers that the data have strongly non-Gaussian uncertainties, requiring the use of both 'median' and 'mean' statistical approaches. Our results reveal that previous analyses using two-point diagnostics greatly underestimated the errors, thereby misinterpreting the level of tension between theoretical predictions and H(z) data. Instead, we demonstrate that as of today, only Einstein-de Sitter is ruled out by the two-point diagnostics at a level of significance exceeding ∼3σ . The R h = ct universe is slightly favoured over the remaining models, including Lambda cold dark matter and Chevalier-Polarski-Linder, though all of them (other than Einstein-de Sitter) are consistent to within 1σ with the measured mean of the h(z i , z j ) diagnostics.Key words: galaxies: distances and redshifts -galaxies: evolution -large-scale structure of Universe -cosmology: observations -cosmology: theory. I N T RO D U C T I O NLambda cold dark matter ( CDM) has done reasonably well accounting for a broad range of data and is therefore correctly viewed as the current standard model of cosmology (see, e.g. Planck Collaboration XXIII 2014). But recent analyses of the two-point correlation function of the cosmic microwave background (Melia 2014;Copi et al. 2015), as well as the Om(z i , z j ) and Omh 2 (z i , z j ) diagnostics applied to measurements of the Hubble expansion rate H(z) (Shafieloo, Sahni & Starobinsky 2012; Sahni, Shafieloo & Starobinsky 2014), appear to have revealed significant tension between its predictions and recent measurements (see, e.g. Zheng et al. 2016).In this paper, we directly address the problems highlighted by the various analyses carried out with the H(z) data, which apparently do not confirm the anticipated transition from early deceleration E-mail: kyleaf@email.arizona.edu (KL); melia@physics.arizona.eduto more recent acceleration in the cosmic expansion rate (Jimenez & Loeb 2002;Moresco et al. 2016a). With this type of work, one typically compiles a unified sample of H(z) versus redshift measurements based on various approaches, including the determination of differ...

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Phantom Cosmological Model with Observational Constraints in f(Q)$f(Q)$ Gravity

Narawade

Mishra

2023

Annalen der Physik

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In this paper, the cosmological model of the Universe has been presented in ffalse(Qfalse)$f(Q)$ gravity and the parameters are constrained from the cosmological data sets. At the beginning, a well motivated form of f(Q)=α+βQn$f(Q) = \alpha + \beta Q^{n}$ has been employed, where α, β, and n are model parameters. The Hubble parameter is obtained in redshift with some algebraic manipulation from the considered form of ffalse(Qfalse)$f(Q)$. Then it is parameterized with the recent Hubble$\text{Hubble}$ data and Pantheon+SHOES$\text{Pantheon} + \text{SHOES}$ data using Markov chain Monte Carlo analysis. The obtained model parameter values are validated with the baryon acoustic oscillation data set. A parametrization of the cosmographic parameters shows the early deceleration and late time acceleration with the transition at zt≈0.75$z_\text{t}\approx 0.75$. The Omfalse(zfalse)$Om(z)$ diagnostics gives positive slope which shows that the model is in the phantom phase. Also the current age of the Universe has been obtained as, t0=13.853.33333pt3.33333ptGyrs$t_{0} = 13.85\nobreakspace \nobreakspace \text{Gyrs}$. Based on the present analysis, it indicates that the ffalse(Qfalse)$f(Q)$ gravity may provide an alternative to dark energy for addressing the current cosmic acceleration.

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Is There Evidence for Dark Energy Evolution?

Cited by 85 publications

References 43 publications

Study of non-canonical scalar field model using various parametrizations of dark energy equation of state

Study of non-canonical scalar field model using various parametrizations of dark energy equation of state

Analysing H(z) data using two-point diagnostics

Phantom Cosmological Model with Observational Constraints in f(Q)$f(Q)$ Gravity

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