Propagation of a string across the cosmological singularity

TL;DR

This paper investigates how quantum strings behave when passing through a cosmological singularity in a specific spacetime model, showing that their dynamics remain well-defined and challenging previous assumptions about singularities.

Contribution

It provides the first analysis of quantum string propagation through a cosmological singularity, demonstrating well-defined dynamics in a model where previous models failed.

Findings

Classical and quantum string dynamics are well-defined across the singularity.

The results challenge the view that cosmological singularities are insurmountable in string theory.

The study focuses on strings winding around a compact dimension in a Milne space model.

Abstract

Our results concern the transition of a quantum string through the singularity of the compactified Milne (CM) space. We restrict our analysis to the string winding around the compact dimension (CD) of spacetime. The CD undergoes contraction to a point followed by re-expansion. We demonstrate that both classical and quantum dynamics of considered string are well defined. Most of presently available calculations strongly suggest that the singularity of a time dependent orbifold is useless as a model of the cosmological singularity. We believe that our results bring, to some extent, this claim into question.