عنوان مجله
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INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS
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چکیده
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We reconsider the holographic dark energy (HDE) model with a slowly time
varying c2(z) parameter in the energy density, namely ρD = 3M2
pc2(z)/L2, where L is the
IR cutoff and z is the redshift parameter. As the system’s IR cutoff we choose the Hubble
radius and the Granda-Oliveros (GO) cutoffs. The latter inspired by the Ricci scalar curvature. We derive the evolution of the cosmological parameters such as the equation of state
and the deceleration parameters as the explicit functions of the redshift parameter z. Then,
we plot the evolutions of these cosmological parameters in terms of the redshift parameter during the history of the universe. Interestingly enough, we observe that by choosing
L = H −1 as the IR cutoff for the HDE with time varying c2(z) term, the present acceleration of the universe expansion can be achieved, even in the absence of interaction between
dark energy and dark matter. This is in contrast to the usual HDE model with constant c2
term, which leads to a wrong equation of state, namely that for dust wD = 0, when the IR
cutoff is chosen the Hubble radius.
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