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arXiv · 1407.4814

On the No-Boundary Proposal for Ekpyrotic and Cyclic Cosmologies

Lorenzo Battarra·Jean-Luc Lehners
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Abstract

The no-boundary proposal provides a compelling theory for the initial conditions of our universe. We study the implications of such initial conditions for ekpyrotic and cyclic cosmologies. These cosmologies allow for the existence of a new type of "ekpyrotic instanton", which describes the creation of a universe in the ekpyrotic contraction phase. Remarkably, we find that the ekpyrotic attractor can explain how the universe became classical. In a cyclic context, in addition to the ekpyrotic instantons there exist de Sitter-like instantons describing the emergence of the universe in the dark energy phase. Our results show that typically the ekpyrotic instantons yield a higher probability. In fact, in a potential energy landscape allowing both inflationary and cyclic cosmologies, the no-boundary proposal implies that the probability for ekpyrotic and cyclic initial conditions is vastly higher than that for inflationary ones.

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Lorenzo Battarra, Jean-Luc Lehners. 2014-12-09. On the No-Boundary Proposal for Ekpyrotic and Cyclic Cosmologies. https://doi.org/10.1088/1475-7516%2F2014%2F12%2F023

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