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An LRS Bianchi type-I cosmological model with time-dependent $\Lambda$ term. (English) Zbl 1119.83028
Summary: We investigate locally rotationally symmetric (LRS) Bianchi type-I cosmological model containing stiff matter with a cosmological term proportional to the Hubble parameter. This variation law for vacuum density has recently been proposed by Schützhold on the basis of quantum field estimations in the curved and expanding background. The model obtained approaches isotropy. The cosmological term tends asymptotically to a genuine cosmological constant and the model tends to a de Sitter universe. We obtain that the present universe is accelerating with a large fraction of cosmological density in the form of cosmological term. Taking matter density equal to half of the vacuum density, as suggested by observation, we obtain a universe age given by $Ht = 0.55$ and a decelerating parameter equal to $2\sigma ^{2}/3H^{2}$.

83D05Relativistic gravitational theories other than Einstein’s
83F05Relativistic cosmology
83C15Closed form solutions of equations in general relativity
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