Perturbations in a non-singular bouncing Universe

TL;DR

This paper develops a non-singular bouncing cosmology model within string theory, analyzing scalar and tensor perturbations to understand potential observable signatures of pre-big bang and ekpyrotic scenarios.

Contribution

It introduces a non-local, covariant dilaton potential to achieve a non-singular bounce and studies the resulting perturbation spectra both analytically and numerically.

Findings

Successfully models a non-singular bouncing universe

Calculates the spectrum of amplified scalar and tensor perturbations

Provides insights on observable consequences of pre-big bang scenarios

Abstract

We complement the low-energy gravi-dilaton effective action of string theory with a non-local, general-covariant dilaton potential, and obtain homogeneous solutions describing a non-singular (bouncing-curvature) cosmology. We then compute, both analytically and numerically, the spectrum of amplified scalar and tensor perturbations, and draw some general lessons on how to extract observable consequences from pre-big bang and ekpyrotic scenarios.