On Perturbations of Quintom Bounce

TL;DR

This paper studies the behavior of cosmological perturbations in a Quintom Bounce universe, showing how fluctuations evolve through the bounce and couple across the contracting and expanding phases.

Contribution

It provides an analytical and numerical analysis of perturbations in the Quintom Bounce, highlighting mode coupling across the bounce.

Findings

Dominant mode fluctuations couple to pre-bounce growing modes.

Perturbations evolve smoothly through the bounce.

Analytical and numerical methods confirm mode coupling.

Abstract

A Quintom universe with an equation-of-state crossing the cosmological constant boundary can provide a bouncing solution dubbed the Quintom Bounce and thus resolve the Big Bang singularity. In this paper, we investigate the cosmological perturbations of the Quintom Bounce both analytically and numerically. We find that the fluctuations in the dominant mode in the post-bounce expanding phase couple to the growing mode of the perturbations in the pre-bounce contracting phase.