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Indexed by:期刊论文

Date of Publication:2009-09-01

Journal:JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

Included Journals:SCIE、Scopus

Volume:2009

Issue:9

ISSN No.:1475-7516

Key Words:quantum gravity phenomenology; dark energy theory

Abstract:The main task of this paper is to realize a cosmic observational compatible universe in the framework of holographic dark energy model when the Hubble horizon H is taken as the role of an IR cut-off. When the model parameter c of a time variable cosmological constant (CC) Lambda( t) = 3c(2)H(2) (t) becomes time or scale dependent, an extra term enters in the effective equation of sate ( EoS) of the vacuum energy w(Lambda)(eff) = -c(2) - d lnc(2) /3d ln a. This extra term can make the effective EoS of time variable CC cross the cosmological boundary and be phantom-like at present. For the lack of a first principle and fundamental physics theory to obtain the form c 2, we give a simple parameterized form of c 2 as an example. Then the model is confronted by the cosmic observations including SN Ia, BAO and CMB shift parameter R. The result shows that the model is consistent with cosmic observations.