Cosmological backreaction of heavy string states

TL;DR

This paper introduces a mechanism where gravitational production of heavy string states causes a smooth transition from a pre-Big Bang phase to a standard cosmological phase by halting curvature growth.

Contribution

It presents a novel model where heavy string states' backreaction facilitates a smooth cosmological transition, supported by numerical solutions.

Findings

Heavy string states can be produced efficiently near the string scale.

Backreaction from these states can halt curvature growth.

Numerical solutions demonstrate the transition mechanism.

Abstract

We propose a mechanism to have a smooth transition from a pre-Big Bang phase to a standard cosmological phase. Such transition is driven by gravitational production of heavy massive string states that backreact on the geometry to stop the growth of the curvature. Close to the string scale, particle creation can become effective because the string phase space compensate the exponential suppression of the particle production. Numerical solutions for the evolution of the Universe with this source are presented.