The nature of cosmological singularities in isotropic universes and braneworlds

TL;DR

This paper classifies finite-time singularities in isotropic cosmological models, including FRW universes and braneworlds, based on Hubble rate behavior and energy conditions, revealing three main singularity types in braneworlds.

Contribution

It provides a new classification scheme for cosmological singularities in both FRW and braneworld models, incorporating the Bel-Robinson energy and asymptotic analysis.

Findings

Classified singularities in FRW universes using Hubble rate behavior.

Extended classification with Bel-Robinson energy.

Identified three main types of singularities in braneworld models.

Abstract

We explore the character of finite-time singularities that are possible to arise in FRW universes and in specific braneworld configurations. For FRW universes, we derive a first classification of singularities that is based on the behaviour of the Hubble rate. We further extend and complete this classification with the use of the Bel-Robinson energy. The braneworld models that we study consist of a three-brane embedded in a five-dimensional bulk space that is inhabited by a scalar field or a perfect fluid. Our analysis that is performed with the method of asymptotic splittings shows that these braneworlds can exhibit three main types of singularities that arise within finite distance from the brane.