One-Loop Superstring Cosmology and the Non-Singular Universe

TL;DR

This paper explores how one-loop string corrections can produce non-singular cosmological models that smoothly transition from contraction to expansion, potentially resolving initial condition issues in closed universe models.

Contribution

It demonstrates the existence of non-singular solutions in string cosmology and analyzes their stability and dependence on initial conditions.

Findings

Non-singular solutions connect contracting and expanding phases.

These solutions reduce the initial conditions problem in closed FRW cosmologies.

Higher order string terms are estimated to be manageable.

Abstract

We study the cosmological implications of the one-loop terms in the string expansion. In particular, we find non-singular solutions which interpolate between a contracting universe and an expanding universe, and show that these solutions provide a mechanism for removing the initial conditions problem peculiar to spatially closed FRW cosmologies. In addition, we perform numerical calculations to show that the non-singular cosmologies do not require a careful choice of initial conditions, and estimate the likely magnitude of higher order terms in the string expansion.