Non-perturbative Orientifolds

TL;DR

This paper explores non-perturbative orientifold compactifications in string theory, revealing new twisted sectors and spectra through duality, including configurations with D-branes and non-perturbative states in four and six dimensions.

Contribution

It introduces a framework for analyzing non-perturbative orientifolds with twisted sectors using Type I-heterotic duality, providing new insights into their spectra and non-perturbative features.

Findings

Identified massless spectra of non-perturbative orientifolds.

Revealed the existence of twisted open string sectors without D-brane description.

Constructed a four-dimensional chiral N=1 supersymmetric vacuum with non-perturbative states.

Abstract

We consider non-perturbative six and four dimensional N=1 space-time supersymmetric orientifolds. Some states in such compactifications arise in ``twisted'' open string sectors which lack world-sheet description in terms of D-branes. Using Type I-heterotic duality we are able to obtain the massless spectra for some of such orientifolds. The four dimensional compactification we discuss in this context is an example of a chiral N=1 supersymmetric string vacuum which is non-perturbative in both orientifold and heterotic pictures. In particular, it contains both D9- and D5-branes plus non-perturbative ``twisted'' open string sector states as well.