Discrete Deformations in Type I Vacua

TL;DR

This paper explores supersymmetric orientifolds with combined world-sheet parity and complex coordinate conjugation, revealing unique deformation properties and their T-duality relations, along with geometric interpretations of certain orientifolds.

Contribution

It introduces a detailed analysis of discrete and continuous moduli in these orientifolds and explains their impact on gauge group rank reduction and geometry.

Findings

Antisymmetric tensor describes a continuous deformation.

Off-diagonal metric components are quantized, causing gauge group rank reduction.

Provides geometric interpretation of six-dimensional permutational orientifolds.

Abstract

We study supersymmetric orientifolds where the world-sheet parity transformation is combined with a conjugation of some compact complex coordinates. We investigate their T-duality relation to standard orientifolds and discuss the origin of continuous and discrete moduli. In contrast to standard orientifolds, the antisymmetric tensor describes a continuous deformation, while the off-diagonal part of the metric is frozen to quantized values and is responsible for the rank reduction of the gauge group. We also give a geometrical interpretation of some recently constructed six-dimensional permutational orientifolds.