Excited states of a string in a time dependent orbifold

TL;DR

This paper analyzes how classical strings in excited states propagate through a cosmological singularity in a time-dependent orbifold, showing that their dynamics remain non-singular during contraction and re-expansion.

Contribution

It provides analytical results demonstrating non-singular propagation of excited classical strings through a cosmological singularity in a time-dependent orbifold.

Findings

Classical string dynamics are non-singular across the singularity.

Analysis is restricted to strings winding around the compact dimension.

Results apply to excited string states in a time-dependent spacetime.

Abstract

We present analytical results on the propagation of a classical string in non-zero modes through the singularity of the compactified Milne space. We restrict our analysis to a string winding around the compact dimension of spacetime. The compact dimension undergoes contraction to a point followed by re-expansion. We demonstrate that the classical dynamics of the string in excited states is non-singular in the entire spacetime.