The stability of Einstein static universe in the DGP braneworld

TL;DR

This paper investigates the stability of Einstein static universes within the DGP braneworld model, revealing conditions under which such universes are stable and can avoid initial singularities.

Contribution

It demonstrates the existence and stability conditions of Einstein static universes in the DGP model, offering a potential resolution to the big bang singularity problem.

Findings

Stable Einstein static universe exists for <w<-1/3 in the  branch.

No stable static solution in the  branch.

Universe can oscillate eternally in a stable static state.

Abstract

The stability of an Einstein static universe in the DGP braneworld scenario is studied in this paper. Two separate branches denoted by $\epsilon=\pm1$ of the DGP model are analyzed. Assuming the existence of a perfect fluid with a constant equation of state, $w$, in the universe, we find that, for the branch with $\epsilon=1$, there is no a stable Einstein static solution, while, for the case with $\epsilon=-1$, the Einstein static universe exists and it is stable when $-1<w<-1/3$. Thus, the universe can stay at this stable state past-eternally and may undergo a series of infinite, non-singular oscillations. Therefore, the big bang singularity problem in the standard cosmological model can be resolved.