Closed String Amplitudes from Gauge Fixed String Field Theory

TL;DR

This paper demonstrates deriving closed string scattering amplitudes from gauge-fixed open string field theory by employing a specific propagator that covers the moduli space of closed string surfaces.

Contribution

It introduces a method to obtain closed string amplitudes directly from open string field theory using a boundary-free propagator and gauge fixing.

Findings

Closed string diagrams are successfully derived from open string field theory.

The approach reproduces the moduli space coverage of closed string surfaces.

A potential gauge fixed form of the string field theory action around the closed string vacuum is proposed.

Abstract

Closed string diagrams are derived from cubic open string field theory using a gauge fixed kinetic operator. The basic idea is to use a string propagator that does not generate a boundary to the world sheet. Using this propagator and the closed string vertex, the moduli space of closed string surfaces is covered, so closed string scattering amplitudes should be reproduced. This kinetic operator could be a gauge fixed form of the string field theory action around the closed string vacuum.