Closed strings in Misner space: a toy model for a Big Bounce ?

TL;DR

This paper explores the behavior of closed strings in Misner space, a simple cosmological singularity model, analyzing semi-classical propagation, twisted sectors, and scattering amplitudes to understand potential resolutions of singularities.

Contribution

It provides a detailed analysis of closed string dynamics in Misner space, highlighting the role of twisted sectors and quantum effects in this cosmological model.

Findings

Semi-classical propagation of closed strings is well-understood in Misner space.

Twisted sectors significantly influence string interactions near the singularity.

One-loop vacuum amplitudes suggest possible mechanisms for singularity resolution.

Abstract

Misner space, also known as the Lorentzian orbifold $R^{1,1}/boost$, is one of the simplest examples of a cosmological singularity in string theory. In this lecture, we review the semi-classical propagation of closed strings in this background, with a particular emphasis on the twisted sectors of the orbifold. Tree-level scattering amplitudes and the one-loop vacuum amplitude are also discussed.