Monodromic strings

TL;DR

This paper introduces monodromic strings, a new string type with properties of both open and closed strings, arising naturally in T-duality scenarios on certain target spaces.

Contribution

It proposes the concept of monodromic strings, demonstrating their emergence in T-duality and their relation to closed strings on dual Poisson-Lie groups.

Findings

Monodromic strings have a state space isomorphic to closed strings.

They naturally appear in T-duality transformations.

On Poisson-Lie groups, monodromic strings are T-dual to closed strings on dual groups.

Abstract

We argue that apart from the standard closed and open strings one may consider a third possibility that we call monodromic strings. The monodromic string propagating on a target looks like an ordinary open string (a mapping from a segment to the target) but its space of states is isomorphic to that of a closed string. It is shown that the monodromic strings naturally appear in T-dualizing closed strings moving on simply connected targets. As a nontrivial topology changing example we show that the monodromic strings on a compact Poisson-Lie group are T-dual to the standard closed strings propagating on the noncompact dual PL group.