On the initial singularity in Kantowski-Sachs spacetime

TL;DR

This paper investigates the possibility of a nonsingular static state in Kantowski-Sachs spacetime within the emergent universe scenario, analyzing how dimensions and fluid properties influence its existence and stability.

Contribution

It extends the emergent universe concept to Kantowski-Sachs models, exploring conditions for nonsingular static states in different dimensions and with various supporting fluids.

Findings

Nonsingular static states can exist in Kantowski-Sachs spacetime.

The stability of these states depends on spacetime dimensions.

Fluid properties critically influence the existence of nonsingular states.

Abstract

The emergent universe scenario is a proposal for resolving the Big Bang singularity problem in the standard Friedmann-Lemaitre-Robertson-Walker cosmology. In the context of this scenario, the Universe originates from a nonsingular static state. In the present work, considering the realization of the emergent universe scenario, we address the possibility of having a nonsingular Kantowski-Sachs type static state. Considering four and five dimensional models (with and without brane), it is shown that both the existence and stability of a nonsingular state depend on the dimensions of the spacetime and the nature of the fluid supporting the geometry.