Nonperturbative Type I-I' String Theory

TL;DR

This paper introduces a nonperturbative matrix model framework for type I string theory, capturing its low energy effective actions, dualities, and connections to M theory, using large N limits and matrix algebra.

Contribution

It proposes a novel matrix-based nonperturbative approach to type I string theory that unifies various dualities and low energy limits within a single formalism.

Findings

Matrix algebra encodes Lorentz, gauge, and supersymmetry algebras.

Planar reduction reproduces the low energy effective action of type I string theory.

Matrix T-duality relates to type I' string theory with D8-branes.

Abstract

We propose a nonperturbative framework for the O(32) type I open and closed string theory. The short distance degrees of freedom are bosonic and fermionic hermitian matrices belonging respectively to the adjoint and fundamental representations of the special unitary group SU(N). We identify a closed matrix algebra at finite N which corresponds to the Lorentz, gauge, and supersymmetry algebras of the large N continuum limit. The planar reduction of our matrix theory coincides with the low energy spacetime effective action of the d=10 type I O(32) unoriented open and closed string theory. We show that matrix T-duality transformations can yield a nonperturbative framework for the T-dual type I' closed string theory with 32 D8branes. We show further that under a strong-weak coupling duality transformation the large N reduced action coincides with the low energy spacetime effective action of the d=10 heterotic string, an equivalence at leading order in the inverse string tension and with either gauge group Spin(32)/Z2 or E8xE8. Our matrix formalism has the potential of providing a nonperturbative framework encapsulating all of the weak coupling limits of M theory.