Regular Article - Theoretical Physics
Generalized holographic and Ricci dark energy models
Institute of Theoretical Physics, School of Physics & Optoelectronic Technology, Dalian University of Technology, Dalian, 116024, People’s Republic of China
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Revised: 15 July 2009
Published online: 22 August 2009
In this paper, we consider generalized holographic and Ricci dark energy models where the energy densities are given as ρ R =3c 2 M pl 2 Rf(H 2/R) and ρ h =3c 2 M pl 2 H 2 g(R/H 2), respectively; here f(x), g(y) are positive defined functions of the dimensionless variables H 2/R or R/H 2. It is interesting that holographic and Ricci dark energy densities are recovered or recovered interchangeably when the function f(x)=g(y)≡1 or f(x)=Id and g(y)=Id are taken, respectively (for example f(x),g(x)=1−ε(1−x), ε=0or1, respectively). Also, when f(x)≡xg(1/x) is taken, the Ricci and holographic dark energy models are equivalent to a generalized one. When the simple forms f(x)=1−ε(1−x) and g(y)=1−η(1−y) are taken as examples, by using current cosmic observational data, generalized dark energy models are considered. As expected, in these cases, the results show that they are equivalent (ε=1−η=1.312), and Ricci-like dark energy is more favored relative to the holographic one where the Hubble horizon was taken as an IR cut-off. And the suggested combination of holographic and Ricci dark energy components would be 1.312R−0.312H 2, which is in terms of H 2 and .
© Springer-Verlag , 2009