A linearly Expanding Universe With Variable G and Lambda
Abstract
Description
We have studied a cosmological model with a cosmological term of the form $Λ=3α\fr{\dot R^2}{R^2}+\bt\fr{\ddot R}{R}+\fr{3γ}{R^2} α, \
\bt γ$ are constants. The scale factor (R) is found to vary linearly with time for both radiation and matter dominated epochs.
The cosmological constant is found to decrease as $t^{-2}$ and the rate of particle creation is smaller than the Steady State value.
The model gives $Ω^Λ=\fr{1}{3}$ and $Ω^m=\fr{2}{3}$ in the present era,
$Ω^Λ=Ω^m=\fr{1}{2}$ in the radiation era.
The present age of the universe $(\rm t_p$) is found to be $\rm t_p=H_p^{-1}$ , where $\rm H_p$ is the Hubble constant.
The model is free from the main problems of the Standard Model. Since the scale factor $\rm R\propto t$ during the entire evolution of the universe the ratio of the cosmological constant at the Planck and present time is $\rm\fr{Λ_{Pl}}{Λ_p}=10^{120}$.
This decay law justifies why, today, the cosmological constant is exceedingly small.
A revised version
A revised version