Fully stable cosmological solutions with a non-singular classical bounce

TL;DR

This paper develops a method to construct fully stable, non-singular bouncing cosmological solutions using extended Galileon actions, avoiding singularities and pathologies present in previous models.

Contribution

It introduces an extension of the Galileon action including the ${ m L}_4$ term to achieve non-singular, stable bouncing solutions throughout cosmic evolution.

Findings

Constructed non-singular bouncing solutions with extended Galileon actions.

Demonstrated stability and absence of singularities at all times.

Provided a viable classical cosmological bounce model.

Abstract

We recently showed how it is possible to use a cubic Galileon action to construct classical cosmological solutions that enter a contracting null energy condition (NEC) violating phase, bounce at finite values of the scale factor and exit into an expanding NEC-satisfying phase without encountering any singularities or pathologies. A drawback of these examples is that singular behavior is encountered at some time either just before or just after the NEC-violating phase. In this Letter, we show that it is possible to circumvent this problem by extending our method to actions that include the next order ${\cal L}_4$ Galileon interaction. Using this approach, we construct non-singular classical bouncing cosmological solutions that are non-pathological for all times.