String Field Theory Solution for Any Open String Background. II

TL;DR

This paper presents a new analytic solution in open bosonic string field theory that can describe any open string background, including time-dependent and multiple D-brane configurations, by using Riemann surface degenerations.

Contribution

It introduces a general solution framework that overcomes previous limitations by handling OPE singularities and associativity anomalies, enabling a comprehensive understanding of D-brane systems.

Findings

Solution describes arbitrary open string backgrounds

Resolves associativity anomalies in string field theory

Provides nonperturbative proof of background independence

Abstract

Generalizing previous work, we give a new analytic solution in Witten's open bosonic string field theory which can describe any open string background. The central idea is to use Riemann surface degenerations as a mechanism for taming OPE singularities. This requires leaving the familiar subalgebra of wedge states with insertions, but the payoff is that the solution makes no assumptions about the reference and target D-brane systems, and is therefore truly general. For example, unlike in previous work, the solution can describe time dependent backgrounds and multiple copies of the reference D-brane within the universal sector. The construction also resolves some subtle issues resulting from associativity anomalies, giving a more complete understanding of the relation between the degrees of freedom of different D-brane systems, and a nonperturbative proof of background independence in classical open bosonic string field theory.