N = 2 Gauge/Gravity Duals

TL;DR

Polchinski analyzes the $N=2$ analog of the Klebanov-Strassler gauge/gravity dual, showing how the enhançon resolves IR singularities in the presence of orbifold and fractional branes. The work delivers an exact $\mathcal{N}=2$ supergravity solution that features a UV duality cascade akin to KS but ends in the characteristic enhançon in the IR. It details the role of a $\mathbb{Z}_2$ orbifold, fractional branes with twisted moduli $\theta_{\rm B}$ and $\theta_{\rm C}$, and an $\mathcal{N}=2$ Seiberg duality in shaping the RG flow and brane content, while connecting related configurations through T-duality and brane rotations. The study also highlights open issues and exotic IR physics associated with the enhançon ring, and sketches how these solutions relate to other brane constructions such as KS and CV-MN via dualities.

Abstract

We study the N = 2 supersymmetric analog of the Klebanov-Strassler system. We first review the resolution of singularities by the enhancon mechanism, and the physics of fractional branes on an orbifold. We then describe the exact N = 2 solution. This exhibits a duality cascade as in the N = 1 case, but the singularity resolution is the characteristic N = 2 enhancon. We discuss some related solutions and open issues.