D-branes and Discrete Torsion II

TL;DR

This paper explores the gauge theories of D-branes on orbifolds with discrete torsion, revealing complex moduli spaces, unusual fractional brane properties, and the gauge symmetry of wrapped D6-branes, advancing understanding of string compactifications.

Contribution

It derives D-brane gauge theories for C^3/Z_n x Z_n orbifolds with discrete torsion and analyzes their moduli spaces and fractional brane properties.

Findings

The moduli space contains n-1 conifold singularities.

Closed string moduli do not fully resolve the singularity.

Wrapped D6-branes have U(n) gauge symmetry.

Abstract

We derive D-brane gauge theories for C^3/Z_n x Z_n orbifolds with discrete torsion and study the moduli space of a D-brane at a point. We show that, as suggested in previous work, closed string moduli do not fully resolve the singularity, but the resulting space -- containing n-1 conifold singularities -- is somewhat surprising. Fractional branes also have unusual properties. We also define an index which is the CFT analog of the intersection form in geometric compactification, and use this to show that the elementary D6-brane wrapped about T^6/Z_n x Z_n must have U(n) world-volume gauge symmetry.