Exact Superstring Motivated Cosmological Models

TL;DR

This paper introduces new exact scalar field cosmological models with multi-exponential potentials inspired by superstring theories, demonstrating diverse expansion phases including transitions between powerlaw and exponential inflation.

Contribution

The work provides novel exact solutions for scalar field cosmologies with multi-exponential potentials motivated by superstring models, covering curved and flat spacetimes.

Findings

Models exhibit multiple phases of expansion

Smooth transition between different inflationary regimes

Potential for complex cosmological evolution

Abstract

We present a number of new, exact scalar field cosmologies where the potential consists of two or more exponential terms. Such potentials are motivated by supergravity or superstring models formulated in higher dimensional spacetimes that have been compactified to (3+1)-dimensions. We have found solutions in both curved and flat Robertson Walker spacetimes. These models have a diverse range of properties and often possess several distinct phases, with a smooth transition between ordinary and inflationary expansion. While exponential potentials typically produce powerlaw inflation, we find models where the inflationary period contains eras of both powerlaw and exponential growth.