Stability of the Einstein static universe in presence of vacuum energy

TL;DR

This paper investigates how vacuum energy influences the stability of the Einstein static universe, demonstrating that it can stabilize the universe and enable non-singular, cyclic emergent cosmological models.

Contribution

It shows that vacuum energy transforms the Einstein static universe into a stable, cyclic equilibrium, facilitating emergent cosmological scenarios without initial singularities.

Findings

Vacuum energy stabilizes the Einstein static universe.

The static solution becomes a cyclically stable center.

Supports non-singular, past-eternal cosmological models.

Abstract

The Einstein static universe has played a central role in a number of emergent scenarios recently put forward to deal with the singular origin of the standard cosmological model. Here we study the existence and stability of the Einstein static solution in presence of vacuum energy corresponding to conformally-invariant fields. We show that the presence of vacuum energy stabilizes this solution by changing it to a centre equilibrium point, which is cyclically stable. This allows non-singular emergent cosmological models to be constructed in which initially the universe oscillates indefinitely about an initial Einstein static solution and is thus past eternal.