D_n Quivers From Branes
Anton Kapustin
TL;DR
Using brane configurations with orbifolds, the paper investigates gauge theories with eight supercharges in $d=3$ and $d=4$, revealing dualities, IR deformations, and exact solutions. It proves a 3d mirror symmetry for $Sp(k)$ with an antisymmetric tensor and $n$ fundamentals via IIB S-duality, uncovering hidden FI deformations in the IR. It constructs and solves a class of finite $N=2$ $d=4$ theories—$D_n$ quivers—via Hitchin systems on orbifold Riemann surfaces, linking their Seiberg-Witten data to $(SO(2n)$ instantons on ${f R}^2 imes T^2)$. The duality structure is shown to be encoded in the moduli space of flat $SO(2n)$ connections on ${T}^2$, consistent with geometric engineering expectations. These results illuminate how brane setups encode nonperturbative dynamics and dualities in low-dimensional supersymmetric gauge theories.
Abstract
D-branes can end on orbifold planes if the action of the orbifold group includes (-1)^{F_L}. We consider configurations of D-branes ending on such orbifolds and study the low-energy theory on their worldvolume. We apply our results to gauge theories with eight supercharges in three and four dimensions. We explain how mirror symmetry for N=4 d=3 gauge theories with gauge group Sp(k) and matter in the antisymmetric tensor and fundamental representations follows from S-duality of IIB string theory. We argue that some of these theories have hidden Fayet-Iliopoulos deformations, not visible classically. We also study a class of finite N=2 d=4 theories (so-called D_n quiver theories) and find their exact solution. The integrable model corresponding to the exact solution is a Hitchin system on an orbifold Riemann surface. We also give a simple derivation of the S-duality group of these theories based on their relationship to SO(2n) instantons on R^2\times T^2.
