Entropy generation and inflation in wave collision induced pre-big-bang cosmology

TL;DR

This paper investigates how gravitational and dilaton wave collisions in a pre-big-bang cosmology can generate sufficient inflation and entropy, highlighting the nonlinear wave interactions as a key mechanism for early universe dynamics.

Contribution

It introduces a model where wave collisions produce inflation and entropy, with quantitative analysis of entropy scaling based on wave focusing lengths.

Findings

Sufficient inflation occurs with weak incoming waves.

Entropy is generated through nonlinear wave interactions.

Entropy scaling relates to focusing lengths of the waves.

Abstract

We study inflation and entropy generation in a recently proposed pre-big-bang model universe produced in a collision of gravitational and dilaton waves. It is shown that enough inflation occurs provided the incoming waves are sufficiently weak. We also find that entropy in this model is dynamically generated as the result of the nonlinear interaction of the incoming waves, before the universe enters the phase of dilaton driven inflation. In particular, we give the scaling of the entropy produced in the collision in terms of the focusing lengths of the incoming waves.