Quantum Fluctuations in Open Pre-Big Bang Cosmology

TL;DR

This paper provides an exact solution for tensor and scalar perturbations in an open pre-big bang cosmological model, showing that vacuum fluctuation amplification is negligible during the perturbative phase.

Contribution

It offers an exact analytical solution for perturbations in the pre-big bang scenario, clarifying the behavior of quantum fluctuations.

Findings

Vacuum fluctuation amplification remains negligible

Exact solutions for perturbations in open pre-big bang models

Supports the stability of the perturbative phase

Abstract

We solve exactly the (linear order) equations for tensor and scalar perturbations over the homogeneous, isotropic, open pre-big bang model recently discussed by several authors. We find that the parametric amplification of vacuum fluctuations (i.e. particle production) remains negligible throughout the perturbative pre-big bang phase.