Non-singular non-flat universes

TL;DR

This paper explores various non-flat cosmological models that avoid initial singularities, including Einstein-Cartan and quantum-corrected universes, revealing stable, nonsingular solutions such as a static Einstein universe.

Contribution

It introduces multiple non-flat universe models that eliminate the initial singularity, expanding the understanding of possible early universe scenarios.

Findings

Several nonsingular universe solutions identified

Existence of a stable, static Einstein universe

Models include Einstein-Cartan and quantum corrections

Abstract

The quest to understand better the nature of the initial cosmological singularity is with us since the discovery of the expanding universe. Here, we propose several non-flat models, among them the standard cosmological scenario with a critical cosmological constant, the Einstein-Cartan cosmology, the Milne-McCrea universe with quantum corrections and a non-flat universe with bulk viscosity. Within these models, we probe into the initial singularity by using different techniques. Several nonsingular universes emerge, one of the possibilities being a static non-expanding and stable Einstein universe.