Cosmic acceleration with a positive cosmological constant
Abstract
We have considered a cosmological model with a phenomenological model for the cosmological constant of the form Λ = β R/R where β is a constant. For an age parameter consistent with observational data, the universe must be accelerating in the presence of a positive cosmological constant. The minimum age of the universe is H^{1}_{0}, where H_{0} is the present Hubble constant. The cosmological constant is found to decrease as t^{2}. Allowing the gravitational constant to change with time leads to an everincreasing gravitational constant at the present epoch. In the presence of a viscous fluid this decay law for Λ is equivalent to the one with Λ = 3αH^{2} (α = const) provided α = β/3(β2). The inflationary solution obtained from this model is that of the de Sitter type.
 Publication:

Classical and Quantum Gravity
 Pub Date:
 January 2003
 DOI:
 10.1088/02649381/20/1/307
 arXiv:
 arXiv:grqc/9905066
 Bibcode:
 2003CQGra..20...93A
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics
 EPrint:
 a more revised version