Fluctuations through a Vibrating Bounce

TL;DR

This paper investigates how oscillations during a non-singular bounce in cosmology influence the evolution of perturbations, revealing characteristic spectral features such as damped oscillations and increased reddening.

Contribution

It introduces a detailed analysis of the impact of superimposed bounce oscillations on cosmological perturbation spectra, highlighting new spectral imprints.

Findings

Spectral oscillations depend on bounce dynamics.

Increased small bounces lead to reddening of the spectrum.

Characteristic damped oscillation features are identified.

Abstract

We study the evolution of cosmological perturbations in a non-singular bouncing cosmology with a bounce phase which has superimposed oscillations of the scale factor. We identify length scales for which the final spectrum of fluctuations obtains imprints of the non-trivial bounce dynamics. These imprints in the spectrum are manifested in the form of damped oscillation features at scales smaller than a characteristic value and an increased reddening of the spectrum at all the scales as the number of small bounces increases.