Abstract
According to classical GR, Anti-de Sitter (AdS) bubbles in the multiverse terminate in big crunch singularities. It has been conjectured, however, that the fundamental theory may resolve these singularities and replace them by nonsingular bounces. This may have important implications for the beginning of the multiverse. Geodesics in cosmological spacetimes are known to be past-incomplete, as long as the average expansion rate along the geodesic is positive, but it is not clear that the latter condition is satisfied if the geodesic repeatedly passes through crunching AdS bubbles. We investigate this issue in a simple multiverse model, where the spacetime consists of a patchwork of FRW regions. The conclusion is that the spacetime is still past-incomplete, even in the presence of AdS bounces.
Highlights
Inflationary cosmology [1,2,3] has profound implications for the global structure of spacetime, for the beginning and the end of the universe
The theorem states that a past-directed geodesic in any spacetime is incomplete, provided that the expansion rate averaged over the affine parameter along the geodesic is positive: Hav > 0
In this paper we investigated how the past geodesic incompleteness of multiverse spacetimes is affected by Anti-de Sitter (AdS) bounces
Summary
Inflationary cosmology [1,2,3] has profound implications for the global structure of spacetime, for the beginning and the end of the universe. The theorem states that a past-directed geodesic in any spacetime is incomplete, provided that the expansion rate averaged over the affine parameter along the geodesic is positive: Hav > 0. The latter condition is expected to hold for past-directed geodesics originating in any inflating region.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
