Fractional Branes, Confinement, and Dynamically Generated Superpotentials

TL;DR

This paper explores how instantons influence supersymmetric gauge theories using type IIA brane constructions, revealing mechanisms behind superpotential generation, supersymmetry breaking, and confinement phenomena.

Contribution

It introduces a brane-based framework to analyze instanton effects, including fractional instantons, in supersymmetric gauge theories, linking string theory constructs to field theory dynamics.

Findings

Instanton-generated superpotentials arise from D-brane interactions.

Certain instanton effects can break supersymmetry in specific models.

Confinement is related to fractional instanton condensates in brane setups.

Abstract

We examine the effects of instantons in four dimensional N=1 supersymmetric gauge theory by including D0-branes in type IIA brane constructions. We examine instanton generated superpotentials in supersymmetric QCD and find that they are due to a repulsive force between D4-branes bound to D0-branes ending on NS 5-branes. We study situations where instanton effects break supersymmetry such as the Intriligator-Thomas-Izawa-Yangagida model and relate this to a IIA brane construction. We also argue how confinement due to a condensate of fractional instantons manifests itself in Super Yang-Mills theory using fractional D0 branes, D4 branes, and NS strings.