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Indexed by:Journal Papers

Date of Publication:2010-06-28

Journal:PHYSICS LETTERS B

Included Journals:SCIE

Volume:690

Issue:4

Page Number:333-336

ISSN No.:0370-2693

Key Words:Time variable cosmological constant; Dark energy

Abstract:In this Letter, time variable cosmological constant, dubbed age cosmological constant, is investigated motivated by the fact: any cosmological length scale and time scale can introduce a cosmological constant or vacuum energy density into Einstein's theory. The age cosmological constant takes the form rho(A) = 3c(2)M(P)(2)/t(A)(2), where t(A) is the age or conformal age of our universe. The effective equation of state (EoS) of age cosmological constant are w(A)(eff) = -1 + 2/3 root Omega A/c and w(A)(eff) = -1 + 2/3 root Omega A/c(1+z) when the age and conformal age of universe are taken as the role of cosmological time scales respectively. The EoS are the same as the so-called agegraphic dark energy models. However, the evolution histories are different from the agegraphic ones for their different evolution equations. (C) 2010 Elsevier B.V. All rights reserved.