Solutions from boundary condition changing operators in open string field theory

TL;DR

This paper constructs analytic solutions in open string field theory using boundary condition changing operators, revealing a universal factorization property and demonstrating convergence in the rolling tachyon example.

Contribution

It introduces a novel approach to open string field theory solutions using boundary condition changing operators with a universal factorization property.

Findings

The component string field factorizes into a matter three-point function and a universal integral.

The universal function depends only on the conformal weight of the state.

Analytic convergence is proven for the rolling tachyon profile.

Abstract

We construct analytic solutions of open string field theory using boundary condition changing (bcc) operators. We focus on bcc operators with vanishing conformal weight such as those for regular marginal deformations of the background. For any Fock space state phi, the component string field <phi,Psi> of the solution Psi exhibits a remarkable factorization property: it is given by the matter three-point function of phi with a pair of bcc operators, multiplied by a universal function that only depends on the conformal weight of phi. This universal function is given by a simple integral expression that can be computed once and for all. The three-point functions with bcc operators are thus the only needed physical input of the particular open string background described by the solution. We illustrate our solution with the example of the rolling tachyon profile, for which we prove convergence analytically. The form of our solution, which involves bcc operators instead of explicit insertions of the marginal operator, can be a natural starting point for the construction of analytic solutions for arbitrary backgrounds.