Duality Twists, Orbifolds, and Fluxes

TL;DR

This paper explores how duality twists in compactifications relate to orbifolds and fluxes, revealing mechanisms for moduli stabilization and exact CFT descriptions in string theory.

Contribution

It introduces a unified framework connecting duality twists, orbifolds, and fluxes, and analyzes their role in stabilizing moduli and constructing gauged supergravities.

Findings

Stable minima of the potential occur at fixed points of the twist group.

Certain twists correspond to exact orbifold CFTs in string theory.

The framework generalizes flux compactifications with nonperturbative U-duality twists.

Abstract

We investigate compactifications with duality twists and their relation to orbifolds and compactifications with fluxes. Inequivalent compactifications are classified by conjugacy classes of the U-duality group and result in gauged supergravities in lower dimensions with nontrivial Scherk-Schwarz potentials on the moduli space. For certain twists, this mechanism is equivalent to introducing internal fluxes but is more general and can be used to stabilize some of the moduli. We show that the potential has stable minima with zero energy precisely at the fixed points of the twist group. In string theory, when the twist belongs to the T-duality group, the theory at the minimum has an exact CFT description as an orbifold. We also discuss more general twists by nonperturbative U-duality transformations.