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Time-Varying Cosmological Term: Emergence and Fate of a FRW Universe

R. Aldrovandi·J. P. Beltran Almeida·J. G. Pereira
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Abstract

A time-varying cosmological "constant" Lambda is consistent with Einstein's equation, provided matter and/or radiation is created or destroyed to compensate for it. Supposing an empty primordial universe endowed with a very large cosmological term, matter will emerge gradually as Lambda decays. Provided only radiation or ultrarelativistic matter is initially created, the universe starts in a nearly de Sitter phase, which evolves towards a FRW regime as expansion proceeds. If, at some cosmological time, the cosmological term begins increasing again, as presently observed, expansion will accelerate and matter and/or radiation will be transformed back into dark energy. It is shown that such accelerated expansion is a route towards a new kind of gravitational singular state, characterized by an empty, conformally transitive spacetime in which all energy is dark.

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R. Aldrovandi, J. P. Beltran Almeida, J. G. Pereira. 2005-04-12. Time-Varying Cosmological Term: Emergence and Fate of a FRW Universe. https://arxiv.org/abs/gr-qc/0312017

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