Cosmological and Wormhole Solutions in Low-Energy Effective String Theory

TL;DR

This paper derives and analyzes cosmological and wormhole solutions within low-energy effective string theory, highlighting scale-factor duality, instanton solutions, and universe nucleation probabilities.

Contribution

It introduces a comprehensive class of solutions in string theory with moduli and electromagnetic fields, emphasizing duality and instanton effects.

Findings

Scale-factor duality invariance in the reduced theory

Existence of Euclidean instantons for universe nucleation

Quantitative probability amplitudes for baby universe formation

Abstract

We derive and study a class of cosmological and wormhole solutions of low-energy effective string field theory. We consider a general four-dimensional string effective action where moduli of the compactified manifold and the electromagnetic field are present. The cosmological solutions of the two-dimensional effective theory obtained by dimensional reduction of the former are discussed. In particular we demonstrate that the two-dimensional theory possesses a scale-factor duality invariance. Euclidean four-dimensional instantons describing the nucleation of the baby universes are found and the probability amplitude for the nucleation process is given.