# Non-Singular Bounces Catalysed by Dark Energy

## TL;DR

This paper explores how dark energy can induce non-singular cosmological bounces in models with positive spatial curvature, including anisotropic scenarios, without violating energy conditions, and discusses their implications for cosmology.

## Contribution

It demonstrates that dark energy enables non-singular bounces in curved cosmologies and analyzes complex anisotropic bounce behaviors, extending understanding of early universe models.

## Key findings

- Dark energy facilitates non-singular bounces without null energy violation.
- Anisotropic Bianchi IX models can have multiple bounces with complex anisotropy evolution.
- Connections to cosmological models and swampland criteria are discussed.

## Abstract

We investigate classically non-singular bounces caused by dark energy. In the presence of positive spatial curvature, vacuum energy, either in the form of a cosmological constant or a scalar field potential, allows for an open set of initial conditions leading to non-singular bounces, without any violation of the null energy condition. We study anisotropic Bianchi IX cosmologies, and demonstrate that they can even have multiple bounces, accompanied by intricate evolutions of the anisotropies that provide a non-singular analogue of mixmaster crunches. The relation of these solutions to more complete cosmological models, as well as to the recently proposed swampland criteria, are briefly discussed.