Coasting Cosmologies with Time Dependent Cosmological Constant
نویسنده
چکیده
The effect of a time dependent cosmological constant is considered in a family of scalartensor theories. FriedmannRobertsonWalker cosmological models for vacuum and perfect fluid matter are found. They have a linear expansion factor, the so called coasting cosmology, the gravitational ”constant” decreases inversely with time; that is these models satisfy the Dirac Hypotheses. The cosmological ”constant” decreases inversely with the square of time, therefore we can have a very small value for it at present time.
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