World-sheet Instantons via the Myers Effect and N=1^* Quiver Superpotentials

TL;DR

This paper investigates how non-perturbative effects in certain supersymmetric quiver gauge theories can be understood through string theory mechanisms, specifically via world-sheet instantons arising from D-brane polarization effects.

Contribution

It provides a stringy interpretation of non-perturbative superpotentials in N=1* quiver models, linking D-brane polarization to world-sheet instantons and exact superpotential calculations.

Findings

Superpotentials are generated by world-sheet instantons on Myers spheres.

Massive vacua involve fractional D3-branes polarizing into 5-brane spheres.

Exact superpotentials match deformations of the Klebanov-Witten conifold theory.

Abstract

In this note we explore the stringy interpretation of non-perturbative effects in N=1^* deformations of the A_{k-1} quiver models. For certain types of deformations we argue that the massive vacua are described by Nk fractional D3-branes at the orbifold polarizing into k concentric 5-brane spheres each carrying fractional brane charge. The polarization of the D3-branes induces a polarization of D-instantons into string world-sheets wrapped on the Myers spheres. We show that the superpotentials in these models are indeed generated by these world-sheet instantons. We point out that for certain parameter values the condensates yield the exact superpotential for a relevant deformation of the Klebanov-Witten conifold theory.