# Quantum matter bounce with a dark energy expanding phase

## TL;DR

This paper presents a quantum cosmological model where a scalar field drives a universe that undergoes a bounce, transitioning through various phases including dust contraction, stiff matter, dark energy expansion, and returning to dust, avoiding singularities.

## Contribution

It introduces a single scalar field model that unifies matter contraction, a quantum bounce, and dark energy expansion within a non-singular cosmological scenario.

## Key findings

- Universe transitions from dust contraction to stiff matter contraction
- Quantum bounce prevents singularity during contraction
- Model naturally incorporates dark energy era after bounce

## Abstract

Analyzing quantum cosmological scenarios containing one scalar field with exponential potential, we have obtained a universe model which realizes a classical dust contraction from very large scales, the initial repeller of the model, and moves to a stiff matter contraction near the singularity, which is avoided due to a quantum bounce. The universe is then launched in a stiff matter expanding phase, which then moves to a dark energy era, finally returning to the dust expanding phase, the final attractor of the model. Hence one has obtained a nonsingular cosmological model where a single scalar field can describe both the matter contracting phase of a bouncing model, necessary to give an almost scale invariant spectrum of scalar cosmological perturbations, and a transient expanding dark energy phase. As the universe is necessarily dust dominated in the far past, usual adiabatic vacuum initial conditions can be easily imposed in this era, avoiding the usual issues appearing when dark energy is considered in bouncing models.