Classical gauge instantons from open strings

TL;DR

This paper demonstrates how open string techniques in D-brane systems can be used to compute and understand classical gauge instantons, connecting string theory methods with traditional field theory instanton calculus.

Contribution

It introduces a string-theoretic approach to calculate gauge instanton corrections using D3/D(-1) brane systems, linking open string amplitudes to classical instanton solutions.

Findings

Disk amplitudes with mixed boundary conditions source classical instantons.

Open string scattering amplitudes reproduce instanton solutions.

The string description aligns with standard field theory instanton calculus.

Abstract

We study the D3/D(-1) brane system and show how to compute instanton corrections to correlation functions of gauge theories in four dimensions using open string techniques. In particular we show that the disks with mixed boundary conditions that are typical of the D3/D(-1) system are the sources for the classical instanton solution. This can then be recovered from simple calculations of open string scattering amplitudes in the presence of D-instantons. Exploiting this fact we also relate this stringy description to the standard instanton calculus of field theory.