Nonperturbative definition of closed string theory via open string field theory

TL;DR

This paper proposes a nonperturbative definition of closed string theory using open string field theory on D-branes, connecting gauge theory correlators with world-sheet theories including holes.

Contribution

It introduces a novel approach to define closed string theory nonperturbatively via open string field theory, based on the equivalence of world-sheet theories with and without holes.

Findings

Open string field theory on D-branes reproduces world-sheet theories with holes.

The 1/N expansion matches the moduli space of Riemann surfaces with holes.

Provides a nonperturbative framework for closed string theory.

Abstract

In typical examples of the AdS/CFT correspondence, the world-sheet theory with holes in the presence of D-branes is assumed to be equivalent in a low-energy limit to a world-sheet theory without holes for a different background such as $AdS_5 \times S^5$. In the case of the bosonic string, we claim under the assumption of this equivalence that open string field theory on $N$ coincident D-branes can be used to provide a nonperturbative definition of closed string theory based on the fact that the $1/N$ expansion of correlation functions of gauge-invariant operators reproduces the world-sheet theory with holes where the moduli space of Riemann surfaces is precisely covered.