Towards a Stringy Resolution of the Cosmological Singularity

TL;DR

This paper explores how string theory corrections might resolve the initial cosmological singularity, resulting in a non-singular universe that transitions from a high-curvature de Sitter phase to a low-curvature Minkowski space.

Contribution

It constructs a string-inspired cosmological model with higher-derivative corrections that avoids singularities, compatible with known string theory constraints.

Findings

Constructed a singularity-free cosmological solution.

Universe transitions from high-curvature de Sitter to low-curvature Minkowski.

Model aligns with string theory restrictions.

Abstract

We study cosmological solutions to the low-energy effective action of heterotic string theory including possible leading order $\alpha'$ corrections and a potential for the dilaton. We consider the possibility that including such stringy corrections can resolve the initial cosmological singularity. Since the exact form of these corrections is not known the higher-derivative terms are constructed so that they vanish when the metric is de Sitter spacetime. The constructed terms are compatible with known restrictions from scattering amplitude and string worldsheet beta-function calculations. Analytic and numerical techniques are used to construct a singularity-free cosmological solution. At late times and low-curvatures the metric is asymptotically Minkowski and the dilaton is frozen. In the high-curvature regime the universe enters a de Sitter phase.