Constraints on cosmological parameters in power-law cosmology

Rani, Sarita; Altaibayeva, Aziza; Shahalam, M.; Singh, J. K.; Myrzakulov, Ratbay

doi:10.1088/1475-7516/2015/03/031

Cited by 68 publications

(71 citation statements)

References 60 publications

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“…In Melia (2015) several claims against R h = ct were refuted, and a list of works favouring R h = ct over ΛCDM was compiled in Melia (2017). Power-law cosmologies with n ≥ 1 have been explored against data in several works such as Gehlaut et al (2003), Dev et al (2008), Sethi et al (2005), Zhu et al (2008), Shafer (2015), Rani et al (2015), Dolgov et al (2014), finding n ∼ 1.5 consistently. In a more recent work (Shafer 2015), power-law and R h = ct models were tested with SN Ia and BAO datasets and were found to be highly disfavoured against ΛCDM.…”

Section: Introductionmentioning

confidence: 99%

Strong evidence for an accelerating Universe

Haridasu

Luković

D’Agostino

et al. 2017

A&A

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A recent analysis of supernova Ia (SN Ia) data claims a "marginal" (∼3σ) evidence for a cosmic acceleration. This result has been complemented with a non-accelerating R h = ct cosmology, which was presented as a valid alternative to the ΛCDM model. In this paper we use the same analysis to show that non-marginal evidence for acceleration is truly found. We compare the standard Friedmann models to the R h = ct cosmology by complementing SN Ia data with baryon acoustic oscillations, gamma ray bursts, and observational Hubble datasets. We also study the power-law model, which is a functional generalisation of R h = ct. We find that the evidence for late-time acceleration cannot be refuted at a 4.56σ confidence level from SN Ia data alone, and at an even stronger confidence level (5.38σ) from our joint analysis. In addition, the non-accelerating R h = ct model fails to statistically compare with the ΛCDM, having a ∆(AIC) ∼ 30.

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Section: Introductionmentioning

confidence: 99%

Strong evidence for an accelerating Universe

Haridasu

Luković

D’Agostino

et al. 2017

A&A

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“…The power-law expansion has been considered widely in astrophysical observations, see e.g. [107][108][109][110] (see also [111] for constraints). It is realized as an attractor solution of a canonical scalar field evolving under exponential potential [112] and solution of a barotropic fluid-dominant universe.…”

Section: Resultsmentioning

confidence: 99%

Non-minimal derivative coupling gravity in cosmology

Gumjudpai

Rangdee

2015

Gen Relativ Gravit

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We give a brief review of the non-minimal derivative coupling (NMDC) scalar field theory in which there is non-minimal coupling between the scalar field derivative term and the Einstein tensor. We assume that the expansion is of power-law type or super-acceleration type for small redshift. The Lagrangian includes the NMDC term, a free kinetic term, a cosmological constant term and a barotropic matter term. For a value of the coupling constant that is compatible with inflation, we use the combined WMAP9 (WMAP9+eCMB+BAO+ H0) dataset, the PLANCK+WP dataset, and the PLANCK T T, T E, EE+lowP+Lensing+ext datasets to find the value of the cosmological constant in the model. Modeling the expansion with power-law gives a negative cosmological constants while the phantom power-law (super-acceleration) expansion gives positive cosmological constant with large error bar. The value obtained is of the same order as in the ΛCDM model, since at late times the NMDC effect is tiny due to small curvature.

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“…Let us remember that the observations suggest q ≈ −0.5 [98,99], albeit models considering power law solutions can also allow for higher limits, i.e. q ≈ −0.3 [100].…”

Section: -D Cylinder Modelsmentioning

confidence: 99%

Higher-order gravity in higher dimensions: geometrical origins of four-dimensional cosmology?

Troisi

2017

Eur. Phys. J. C

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Determining the cosmological field equations is still very much debated and led to a wide discussion around different theoretical proposals. A suitable conceptual scheme could be represented by gravity models that naturally generalize Einstein theory like higher-order gravity theories and higher-dimensional ones. Both of these two different approaches allow one to define, at the effective level, Einstein field equations equipped with source-like energymomentum tensors of geometrical origin. In this paper, the possibility is discussed to develop a five-dimensional fourth-order gravity model whose lower-dimensional reduction could provide an interpretation of cosmological fourdimensional matter-energy components. We describe the basic concepts of the model, the complete field equations formalism and the 5-D to 4-D reduction procedure. Fivedimensional f (R) field equations turn out to be equivalent, on the four-dimensional hypersurfaces orthogonal to the extra coordinate, to an Einstein-like cosmological model with three matter-energy tensors related with higher derivative and higher-dimensional counter-terms. By considering the gravity model with f (R) = f 0 R n the possibility is investigated to obtain five-dimensional power law solutions. The effective four-dimensional picture and the behaviour of the geometrically induced sources are finally outlined in correspondence to simple cases of such higher-dimensional solutions.

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Constraints on cosmological parameters in power-law cosmology

Cited by 68 publications

References 60 publications

Strong evidence for an accelerating Universe

Strong evidence for an accelerating Universe

Non-minimal derivative coupling gravity in cosmology

Higher-order gravity in higher dimensions: geometrical origins of four-dimensional cosmology?

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