scholarly journals Large-scale (in) stability analysis of an exactly solved coupled dark-energy model

2018 ◽  
Vol 98 (4) ◽  
Author(s):  
Weiqiang Yang ◽  
Supriya Pan ◽  
Ramón Herrera ◽  
Subenoy Chakraborty
Keyword(s):  
Dark Energy ◽  
Stability Analysis ◽  
Dark Energy Model ◽  
Large Scale ◽  
Energy Model

A PARAMETRIZED VARIABLE DARK ENERGY MODEL: STRUCTURE FORMATION AND OBSERVATIONAL CONSTRAINTS

2006 ◽  
Vol 15 (09) ◽  
pp. 1455-1472 ◽  
Author(s):  
S. ARBABI BIDGOLI ◽  
M. SADEGH MOVAHED ◽  
S. RAHVAR
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Large Scale ◽  
High Redshift ◽  
Growth Index ◽  
Energy Model ◽  
Linear Perturbation ◽  
Model Parameters ◽  
Type Ia ◽  
Parametrization Scheme

In this paper we investigate a simple parametrization scheme of the quintessence model given by Wetterich [Phys. Lett. B594, 17 (2004)]. The crucial parameter of this model is the bending parameter b, which is related to the amount of dark energy in the early universe. Using the linear perturbation and the spherical infall approximations, we investigate the evolution of matter density perturbations in the variable dark energy model, and obtain an analytical expression for the growth index f. We show that increasing b leads to less growth of the density contrast δ, and also decreases the growth index. Giving a fitting formula for the growth index at the present time, we verify that the approximation relation [Formula: see text] also holds in this model. To compare predictions of the model with observations, we use the Supernovae type Ia (SNIa) Gold Sample and the parameters of the large scale structure determined by the 2-degree Field Galaxy Redshift Survey (2dFGRS). The best fit values for the model parameters by marginalizing on the remained ones, are [Formula: see text], [Formula: see text] and [Formula: see text] at 1σ confidence level. As a final test we calculate the age of universe for different choices of the free parameters in this model and compare it with the age of old stars and some high redshift objects. Then we show that the predictions of this variable dark energy model are consistent with the age observation of old star and can solve the "age crisis" problem.

scholarly journals Stability analysis of a Tsallis holographic dark energy model

2019 ◽  
Vol 36 (17) ◽  
pp. 175001 ◽  
Author(s):  
Qihong Huang ◽  
He Huang ◽  
Jun Chen ◽  
Lu Zhang ◽  
Feiquan Tu
Keyword(s):  
Dark Energy ◽  
Stability Analysis ◽  
Dark Energy Model ◽  
Holographic Dark Energy ◽  
Energy Model ◽  
Holographic Dark Energy Model

Stability Analysis of the Viscous Polytropic Dark Energy Model in Einstein Cosmology

2016 ◽  
Vol 33 (10) ◽  
pp. 100403
Author(s):  
Yue-Yi Wang ◽  
Ju-Hua Chen ◽  
Yong-Jiu Wang
Keyword(s):  
Dark Energy ◽  
Stability Analysis ◽  
Dark Energy Model ◽  
Energy Model

scholarly journals Observational constraints on interacting Tsallis holographic dark energy model

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Ehsan Sadri
Keyword(s):  
Dark Energy ◽  
Observational Data ◽  
Dark Energy Model ◽  
Large Scale ◽  
Gamma Ray ◽  
Holographic Dark Energy ◽  
Energy Model ◽  
Late Time ◽  
Acoustic Oscillations ◽  
Holographic Dark Energy Model

Abstract In this paper, we investigate a recent proposed model – so called the Tsallis holographic dark energy (THDE) model with consideration of the Hubble and the event future horizon as IR cutoffs. In this case, we consider the non-gravitational and phenomenological interaction between dark sectors. We fit the free parameters of the model using Pantheon Supernovae Type Ia data, Baryon Acoustic Oscillations, Cosmic Microwave Background, Gamma-Ray burst and the the local value of the Hubble constant. We examine the THDE model to check its compatibility with observational data using objective Information Criterion (IC). We find that the THDE models cannot be supported by observational data once the $$\Lambda $$ΛCDM is considered as the referring model. Therefore we re-examine the analysis with the standard holographic dark energy model (HDE) as another reference. Changing the $$\Lambda $$ΛCDM to main standard dark energy model (HDE), we observe the compatibility of the THDE models. Using the Alcock–Paczynski (AP) test we check the deviation of the model compared to $$\Lambda $$ΛCDM and HDE. Surveying the evolution of squared of sound speed $$v^2_s$$vs2 as an another test we check the stability of the interacting and non-interacting THDE models and we find that while the THDE model with the Hubble horizon as IR cutoff is unstable against the background perturbation, the future event horizon as IR cutoff show stability at the late time. In addition, using the modified version of the CAMB package, we observe the suppressing the CMB spectrum at small K-modes and large scale.

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