Interactions of type IIB D-branes from D-instanton matrix model

TL;DR

This paper calculates interaction potentials between specific D-brane configurations in type IIB string theory, showing agreement between supergravity and matrix model results, and clarifies the role of D-instantons in bound states.

Contribution

It demonstrates the detailed agreement between supergravity and matrix model calculations for D-brane interactions, confirming the interpretation of D-branes as bound states of D-instantons.

Findings

Confirmed the match between supergravity and matrix model potentials.

Established the relation between matrix model expressions and super Yang-Mills terms.

Validated the interpretation of D-branes as bound states of D-instantons.

Abstract

We compute long-distance interaction potentials between certain 1/2 and 1/4 supersymmetric D-brane configurations of type IIB theory, demonstrating detailed agreement between classical supergravity and one-loop instanton matrix model results. This confirms the interpretation of D-branes as described by classical matrix model backgrounds as being `populated' by large number of D-instantons, i.e. as corresponding to non-marginal bound states of branes of lower dimensions. In the process, we establish precise relation between matrix model expressions and non-abelian F^4 terms in the super Yang-Mills effective action.