scholarly journals Quadrature algorithms to the luminosity distance with a time-dependent dark energy model

2011 ◽  
Vol 2011 (11) ◽  
pp. 047-047 ◽  
Author(s):  
Nan-Nan Yue ◽  
De-Zi Liu ◽  
Xiao-Xing Pei ◽  
Fang-Fang Zhu ◽  
Tong-Jie Zhang ◽  
...  
2013 ◽  
Vol 91 (8) ◽  
pp. 662-667 ◽  
Author(s):  
A. Sheykhi ◽  
E. Ebrahimi ◽  
Y. Yousefi

It was argued that the vacuum energy of the Veneziano ghost field of QCD, in a time-dependent background, can be written in the general form, H + O(H2), where H is the Hubble parameter. Based on this, a phenomenological dark energy model whose energy density is of the form ρ = αH + βH2 was recently proposed to explain the dark energy dominated universe. In this paper, we investigate this generalized ghost dark energy model in the setup of Brans–Dicke cosmology. We study the cosmological implications of this model. In particular, we obtain the equation of state, the deceleration parameters, and a differential equation governing the evolution of this dark energy model. It is shown that the equation of state parameter of the generalized ghost dark energy can cross the phantom line (wD = −1) in some range of the parameters spaces.


2014 ◽  
Vol 356 (1) ◽  
pp. 173-180 ◽  
Author(s):  
E. H. Baffou ◽  
A. V. Kpadonou ◽  
M. E. Rodrigues ◽  
M. J. S. Houndjo ◽  
J. Tossa

2013 ◽  
Vol 28 (39) ◽  
pp. 1350171 ◽  
Author(s):  
PENG HUANG ◽  
YONG-CHANG HUANG ◽  
FANG-FANG YUAN

Commonly used boundary conditions in reconstructing f(T) gravity from holographic Ricci dark energy (RDE) model are found to cause some problem, we therefore propose new boundary conditions in this paper. By reconstructing f(T) gravity from the RDE with these new boundary conditions, we show that the new ones are better than the present commonly used ones since they can give the physically expected information, which is lost when the commonly used ones are taken in the reconstruction, of the resulting f(T) theory. Thus, the new boundary conditions proposed here are more suitable for the reconstruction of f(T) gravity.


Author(s):  
H. Hossienkhani ◽  
N. Azimi ◽  
H. Yousefi

The impact of anisotropy on the Ricci dark energy cosmologies is investigated where it is assumed that the geometry of the universe is described by Bianchi type I (BI) metric. The main goal is to determine the astrophysical constraints on the model by using the current available data as type Ia supernovae (SNIa), the Baryon Acoustic Oscillation (BAO), and the Hubble parameter [Formula: see text] data. In this regard, a maximum likelihood method is applied to constrain the cosmological parameters. Combining the data, it is found out that the allowed range for the density parameter of the model stands in [Formula: see text]. With the help of the Supernova Legacy Survey (SNLS) sample, we estimate the possible dipole anisotropy of the Ricci dark energy model. Then, by using a standard [Formula: see text] minimization method, it is realized that the transition epoch from early decelerated to current accelerated expansion occurs faster in Ricci dark energy model than [Formula: see text]CDM model. The results indicate that the BI model for the Ricci dark energy is consistent with the observational data.


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