Heterotic and Type I String Dynamics from Eleven Dimensions

TL;DR

This paper explores the relationship between heterotic and Type I string theories through an eleven-dimensional framework, revealing insights into their dualities and strong coupling behaviors.

Contribution

It proposes an eleven-dimensional origin for the heterotic string and explains dualities as arising from symmetries of this higher-dimensional theory.

Findings

Heterotic string relates to an 11D orbifold theory.

Duality between heterotic and Type I strings explained via 11D symmetries.

Strong coupling behavior of heterotic string derived from 11D perspective.

Abstract

We propose that the ten-dimensional $E_8\times E_8$ heterotic string is related to an eleven-dimensional theory on the orbifold ${\bf R}^{10}\times {\bf S}^1/{\bf Z}_2$ in the same way that the Type IIA string in ten dimensions is related to ${\bf R}^{10}\times {\bf S}^1$. This in particular determines the strong coupling behavior of the ten-dimensional $E_8\times E_8$ theory. It also leads to a plausible scenario whereby duality between $SO(32)$ heterotic and Type I superstrings follows from the classical symmetries of the eleven-dimensional world, just as the $SL(2,{\bf Z})$ duality of the ten-dimensional Type IIB theory follows from eleven-dimensional diffeomorphism invariance.