Notes on the post-bounce background dynamics in bouncing cosmologies

TL;DR

This paper examines the post-bounce dynamics in bouncing cosmologies driven by scalar fields, revealing limitations in cyclic models for explaining late-time acceleration and proposing new cosmological constraints.

Contribution

It analyzes existing bounce models with scalar fields and introduces constraints on a new cyclic model, highlighting their inability to explain late-time acceleration.

Findings

Existing models lead to cyclic evolutions without late-time acceleration.

Cyclic models studied are not cosmologically viable.

Derived constraints on a recently proposed cyclic model.

Abstract

We investigate the post-bounce background dynamics in a certain class of single bounce scenarios studied in the literature, in which the cosmic bounce is driven by a scalar field with negative exponential potential such as the ekpyrotic potential. We show that those models can actually lead to cyclic evolutions with repeated bounces. These cyclic evolutions, however, do not account for the currently observed late-time accelerated expansion and hence are not cosmologically viable. In this respect we consider a new kind of cyclic model proposed recently and derive some cosmological constraints on this model.