Orbifold and Orientifold Compactifications of F-Theory and M-Theory to Six and Four Dimensions

TL;DR

This paper explores orbifold compactifications of F-theory and their dualities with M-theory and type IIB string theory, revealing new orientifolds and properties akin to discrete torsion in lower-dimensional models.

Contribution

It demonstrates dualities between orbifold compactifications of F-theory, M-theory, and type IIB string theory, and predicts new orientifolds based on these mappings.

Findings

Identification of dualities among F-theory, M-theory, and type IIB orientifolds.

Discovery of properties similar to discrete torsion in M and F-theory.

Prediction of new orientifolds in 4-dimensional compactifications.

Abstract

We study orbifold compactifications of F-theory which lead to $N=1$ supersymmetry in 6 and 4 spacetime dimensions. These are dual to specific orientifolds of M-theory, and in many cases to orientifolds of type IIB string theory. The equivalences are demonstrated by mapping the orbifolding transformations in the F, M and string theories to each other using dualities. We observe that M and F-theory appear to possess a property similar to discrete torsion in string theory. This is related to an ambiguity recently noted by Polchinski in the orientifold projection for 6-dimensional models. The 4-dimensional compactifications exhibit similar features, from which we predict the existence of certain new orientifolds of type IIB. Some orbifolds with higher supersymmetry are also examined.