Cosmic age, statefinder, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>O</mml:mi><mml:mi>m</mml:mi></mml:math>diagnostics in the decaying vacuum cosmology

Tong, Minglei; Zhang, Yang

doi:10.1103/physrevd.80.023503

Cited by 51 publications

(67 citation statements)

References 87 publications

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“…The Om(z) diagnostic [39] has been proposed to differentiate C DM to other DE models. Many authors [71][72][73] have studied the DE models based on Om(z) diagnostic. Its constant behaviour with respect to z represents that DE is a cosmological constant ( C DM).…”

Section: Om Diagnosticmentioning

confidence: 99%

Viscous cosmology in new holographic dark energy model and the cosmic acceleration

Singh

Srivastava

2018

Eur. Phys. J. C

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In this work, we study a flat FriedmannRobertson-Walker universe filled with dark matter and viscous new holographic dark energy. We present four possible solutions of the model depending on the choice of the viscous term. We obtain the evolution of the cosmological quantities such as scale factor, deceleration parameter and transition redshift to observe the effect of viscosity in the evolution. We also emphasis upon the two independent geometrical diagnostics for our model, namely the statefinder and the Om diagnostics. In the first case we study new holographic dark energy model without viscous and obtain power-law expansion of the universe which gives constant deceleration parameter and statefinder parameters. In the limit of the parameter, the model approaches to C DM model. In new holographic dark energy model with viscous, the bulk viscous coefficient is assumed as ζ = ζ 0 + ζ 1 H , where ζ 0 and ζ 1 are constants, and H is the Hubble parameter. In this model, we obtain all possible solutions with viscous term and analyze the expansion history of the universe. We draw the evolution graphs of the scale factor and deceleration parameter. It is observed that the universe transits from deceleration to acceleration for small values of ζ in late time. However, it accelerates very fast from the beginning for large values of ζ . By illustrating the evolutionary trajectories in r −s and r −q planes, we find that our model behaves as an quintessence like for small values of viscous coefficient and a Chaplygin gas like for large values of bulk viscous coefficient at early stage. However, model has close resemblance to that of the C DM cosmology in late time. The Om has positive and negative curvatures for phantom and quintessence models, respectively depending on ζ . Our study shows that the bulk viscosity plays very important role in the expansion history of the universe. a

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Section: Om Diagnosticmentioning

confidence: 99%

Viscous cosmology in new holographic dark energy model and the cosmic acceleration

Singh

Srivastava

2018

Eur. Phys. J. C

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“…This distinguishing method is a geometrical diagnosis in a model-independent manner and in principle needs high-precision observational data. Since different DE models exhibit different evolution trajectories in the r -s plane, especially being separated distinctively with the values of {r 0 , s 0 }, the statefinder can be used to diagnose different DE models [47][48][49][50][51][52][53][54][55].…”

Section: Introductionmentioning

confidence: 99%

Comparing holographic dark energy models with statefinder

Cui

Zhang

2014

Eur. Phys. J. C

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We apply the statefinder diagnostic to the holographic dark energy models, including the original holographic dark energy (HDE) model, the new holographic dark energy model, the new agegraphic dark energy (NADE) model, and the Ricci dark energy model. In the low-redshift region the holographic dark energy models are degenerate with each other and with the CDM model in the H (z) and q(z) evolutions. In particular, the HDE model is highly degenerate with the CDM model, and in the HDE model the cases with different parameter values are also in strong degeneracy. Since the observational data are mainly within the low-redshift region, it is very important to break this lowredshift degeneracy in the H (z) and q(z) diagnostics by using some quantities with higher order derivatives of the scale factor. It is shown that the statefinder diagnostic r (z) is very useful in breaking the low-redshift degeneracies. By employing the statefinder diagnostic the holographic dark energy models can be differentiated efficiently in the low-redshift region. The degeneracy between the holographic dark energy models and the CDM model can also be broken by this method. Especially for the HDE model, all the previous strong degeneracies appearing in the H (z) and q(z) diagnostics are broken effectively. But for the NADE model, the degeneracy between the cases with different parameter values cannot be broken, even though the statefinder diagnostic is used. A direct comparison of the holographic dark energy models in the r -s plane is also made, in which the separations between the models (including the CDM model) can be directly measured in the light of the current values {r 0 , s 0 } of the models.

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“…Some works [38][39][40][41][42][43][44][45][46][47] revealed that the statefinder diagnostic can effectively discriminate various DE models and break/differentiate the degeneracies between different parameter values of DE model, except for a few models (for example, the new agegraphic DE model [45,47]). Furthermore, Arabsalmani and Sahni [48] introduced the statefinder hierarchy and the growth rate of linear perturbations as "null diagnostics" for the ΛCDM model.…”

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confidence: 99%

A closer look at interacting dark energy with statefinder hierarchy and growth rate of structure

Cui

Yin

Wang

et al. 2015

J. Cosmol. Astropart. Phys.

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Abstract. We investigate the interacting dark energy models by using the diagnostics of statefinder hierarchy and growth rate of structure. We wish to explore the deviations from ΛCDM and to differentiate possible degeneracies in the interacting dark energy models with the geometrical and structure growth diagnostics. We consider two interacting forms for the models, i.e., Q 1 = βHρ c and Q 2 = βHρ de , with β being the dimensionless coupling parameter. Our focus is the IΛCDM model that is a one-parameter extension to ΛCDM by considering a direct coupling between the vacuum energy (Λ) and cold dark matter (CDM), with the only additional parameter β. But we begin with a more general case by considering the IwCDM model in which dark energy has a constant w (equation-of-state parameter). For calculating the growth rate of structure, we employ the "parametrized post-Friedmann" theoretical framework for interacting dark energy to numerically obtain the (z) values for the models. We show that in both geometrical and structural diagnostics the impact of w is much stronger than that of β in the IwCDM model. We thus wish to have a closer look at the IΛCDM model by combining the geometrical and structural diagnostics. We find that the evolutionary trajectories in the S (1) 3 -plane exhibit distinctive features and the departures from ΛCDM could be well evaluated, theoretically, indicating that the composite null diagnostic {S (1) 3 , } is a promising tool for investigating the interacting dark energy models. We also compare our results with the observed uncertainties on diagnostic parameters. We find that current observations still do not have sufficient precisions to completely distinguish IΛCDM models from the ΛCDM model. Anyway, our work points out what precisions of measurements should be achieved to distinguish the IΛCDM models from the ΛCDM model.

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Cosmic age, statefinder, andOmdiagnostics in the decaying vacuum cosmology

Cited by 51 publications

References 87 publications

Viscous cosmology in new holographic dark energy model and the cosmic acceleration

Viscous cosmology in new holographic dark energy model and the cosmic acceleration

Comparing holographic dark energy models with statefinder

A closer look at interacting dark energy with statefinder hierarchy and growth rate of structure

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