Bound States of Type I' D-particles and Enhanced Gauge Symmetry

TL;DR

This paper investigates D-particle bound states in Type I' theory, demonstrating how their massless limits lead to enhanced gauge symmetry and connecting these findings with dualities and matrix model descriptions.

Contribution

It provides a detailed analysis of D-particle bound states using matrix models, clarifying their role in gauge symmetry enhancement and duality relations.

Findings

Bound states become massless at infinite coupling, leading to enhanced gauge symmetry.

Matrix model analysis supports duality predictions and clarifies bound state properties.

Results connect Type I' bound states with heterotic and M-theory gauge structures.

Abstract

Duality between the E_8 x E_8 heterotic string and Type I' theory predicts a tower of D(irichlet)-particle bound states corresponding to perturbative heterotic string states. In the limit of infinite Type I' coupling, some of these bound states become massless, giving rise to enhanced E_8 x E_8 gauge symmetry. By taking a different infinite coupling limit, one can recover the E_8 x E_8 gauge bosons of M-theory, compactified on S^1/Z_2. In this paper we use the matrix model description of the D-particle dynamics to study these bound states. We find results consistent with the chain of dualities and clarify a number of issues that arise in the application of the matrix mechanics to this system.