Non-commutative (D)-instantons

TL;DR

This paper demonstrates how D-brane systems in a magnetic background can model non-commutative gauge instantons, linking string theory configurations with non-commutative ADHM moduli and their classical profiles.

Contribution

It establishes a correspondence between open string degrees of freedom on D-branes and non-commutative instanton moduli, providing a string-theoretic derivation of non-commutative gauge instantons.

Findings

Open string modes match non-commutative ADHM moduli.

Disk diagrams source classical instanton profiles.

Perturbative agreement with non-commutative ADHM construction.

Abstract

We study systems of D3 and D(-1) branes in a NS-NS magnetic background and show that, when the brane configuration is stable, the physical degrees of freedom of the open strings with at least one end-point on the D-instantons describe the ADHM moduli of instantons for non-commutative gauge theories. We also prove that disk diagrams with mixed boundary conditions are the sources for the classical profile of the non-commutative gauge instantons in the singular gauge. We finally compare the string theory description in a large distance expansion with the non-commutative ADHM construction in the singular gauge and find complete agreement at perturbative level in the non-commutativity parameter.