A Closed, Expanding Universe in String Theory

TL;DR

This paper introduces a conformal field theory model from a gauged WZW model that describes a closed, inhomogeneous universe in 3+1 dimensions, which expands and recollapses, avoiding cosmic censorship violation.

Contribution

It provides a novel string theory-based model of an inhomogeneous, recollapsing universe that aligns with four-dimensional Minkowski space in central charge.

Findings

Universe recollapses before naked singularity forms

Model has central charge c=4, matching 4D Minkowski space

Avoids violation of cosmic censorship

Abstract

We present a conformal field theory -- obtained from a gauged WZW model -- that describes a closed, inhomogeneous expanding and recollapsing universe in $3+1$ dimensions. A possible violation of cosmic censorship is avoided because the universe recollapses just when a naked singularity was about to form. The model has been chosen to have $c=4$ (or $\widehat c=4$ in the supersymmetric case), just like four dimensional Minkowski space.