On the Complementarity of F-theory, Orientifolds, and Heterotic Strings

TL;DR

This paper explores the duality between F-theory, heterotic strings, and orientifolds in six dimensions, demonstrating how to recover perturbative descriptions in strongly coupled regimes and relating different compactifications.

Contribution

It provides a method to use orientifold limits of F-theory duals to analyze strongly coupled heterotic vacua and reproduces specific spectra through F-theory constructions.

Findings

Reproduces spectrum of a $T^4/\ZZ_{4}$ orientifold via F-theory.

Relates F-theory vacua to heterotic $E_8\times E_8$ compactifications on $K3$.

Shows how to regain perturbative descriptions in strongly coupled regimes.

Abstract

We study F-theory duals of six dimensional heterotic vacua in extreme regions of moduli space where the heterotic string is very strongly coupled. We demonstrate how to use orientifold limits of these F-theory duals to regain a perturbative string description. As an example, we reproduce the spectrum of a $T^4/\ZZ_{4}$ orientifold as an F-theory vacuum with a singular $K3$ fibration. We relate this vacuum to previously studied heterotic $E_8\times E_8$ compactifications on $K3$.