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arXiv · 1808.08327

Big bounce and closed universe from spin and torsion

Gabriel Unger·Nikodem Popławski
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Abstract

We analyze the dynamics of a homogeneous and isotropic universe in the Einstein$--$Cartan theory of gravity. The coupling between the spin and torsion prevents gravitational singularities and replaces the Big Bang with a nonsingular big bounce, at which the universe transitions from contraction to expansion. We show that a closed universe exists only when the product of the scale factor and temperature is higher than a particular threshold, contrary to a flat universe and an open universe, which are not restricted. During inflation, this product must increase to another threshold, so that the universe can reach dark-energy acceleration.

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Gabriel Unger, Nikodem Popławski. 2018-08-24. Big bounce and closed universe from spin and torsion. https://doi.org/10.3847/1538-4357/aaf169

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