Orientifold and Type II Dual Pairs

TL;DR

This paper explores symmetries in toroidally compactified type II string theories, identifying new discrete symmetries and constructing dual pairs with matched spectra and supersymmetries in four dimensions.

Contribution

It introduces novel discrete symmetries related to U-duality and constructs explicit type II dual pairs in four dimensions with matching physical properties.

Findings

Identified a symmetry exchanging left and right-moving coordinates.

Discovered a discrete symmetry related to improper T-duality rotation.

Constructed explicit examples of dual pairs with matching spectra and supersymmetries.

Abstract

In this paper we present a symmetry of a toroidally compactified type II string theory. This symmetry has the interpretaion that it interchanges the left and the right-moving worldsheet coordinates and reverses the orientations of some of the spatial coordinates. We also identify another discrete symmetry of the type II theory which is related to the above one by a nontrivial U-duality element of string theory. This symmetry, however, has trivial action on the worldsheet coordinates and corresponds to an improper T-duality rotation. We then construct examples of type II dual pairs in four dimensions by modding out the known type II dual pairs by the above symmetries. We show the explicit matching of the spectrum and supersymmetries in these examples.