Type I on (Generalized) Voisin-Borcea Orbifolds and Non-perturbative Orientifolds

TL;DR

This paper explores non-perturbative four-dimensional N=1 supersymmetric orientifolds derived from Type I on Voisin-Borcea orbifolds, revealing new twisted sectors and analyzing their spectra via dualities, with implications for string vacua consistency.

Contribution

It introduces a detailed analysis of non-perturbative orientifolds on Voisin-Borcea orbifolds, including twisted sectors and their spectra, using dualities to understand their properties and inconsistencies.

Findings

Identification of twisted open string sectors without D-brane descriptions.

Massless spectra of non-perturbative orientifolds obtained via dualities.

Explanation of origins of inconsistencies in certain gauge bundle choices.

Abstract

We consider non-perturbative four dimensional N=1 space-time supersymmetric orientifolds corresponding to Type I compactifications on (generalized) Voisin-Borcea orbifolds. 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 as well as the map between Type IIB orientifolds and F-theory we are able to obtain the massless spectra of such orientifolds. The four dimensional compactifications we discuss in this context are examples of chiral N=1 supersymmetric string vacua which are non-perturbative from both orientifold and heterotic points of view. In particular, they contain both D9- and D5-branes as well as non-perturbative ``twisted'' open string sector states. We also explain the origins of various inconsistencies arising in such compactifications for certain choices of the gauge bundle.