Singularity scattering laws for bouncing cosmologies: a brief overview

TL;DR

This paper reviews a new framework for understanding bouncing cosmologies using singularity scattering maps, classifying all possible junction conditions at the bounce, including three universal laws.

Contribution

It introduces a novel methodology based on singularity scattering maps and cyclic spacetimes to classify bouncing junction conditions in cosmology.

Findings

Classification of all allowed bouncing junction conditions

Identification of three universal bouncing laws

Development of a new methodology for analyzing bouncing cosmologies

Abstract

For contracting/expanding bouncing cosmologies, the formulation of junction conditions at a bouncing was recently revisited by the author in collaboration with B. Le Floch and G. Veneziano. The regime of interest here is the so-called quiescent regime, in which a monotone behavior of the metric is observed and asymptotic expansions can be derived. Here, we overview our new methodology based on the notion of {\sl singularity scattering maps} and {\sl cyclic spacetimes}, and we present our main conclusions. In particular, we provide a classification of all allowed bouncing junction conditions, including three universal laws.