Gauge Fixing and Scattering Amplitudes in String Field Theory Expanded around Universal Solutions

TL;DR

This paper investigates gauge fixing and scattering amplitudes in open string field theory expanded around a universal solution, revealing how amplitudes behave for different parameter values and supporting the idea that the solution can be a pure gauge or tachyon vacuum.

Contribution

It provides an analytic study of scattering amplitudes around the universal solution in string field theory, clarifying the nature of the solution as pure gauge or tachyon vacuum.

Findings

For a > -1/2, open string scattering amplitudes are reproduced in the gauge-fixed theory.

At a = -1/2, all scattering amplitudes vanish, indicating no open string excitations.

Results support the conjecture that the universal solution is either pure gauge or represents the tachyon vacuum.

Abstract

We study a gauge fixed action of open string field theory expanded around the universal solution which has been found as an analytic classical solution with one parameter a. For a>-1/2, we are able to reproduce open string scattering amplitudes in the theory fixed in the Siegel gauge. At a=-1/2, all scattering amplitudes vanish and there is no open string excitation in the gauge fixed theory. These results support the conjecture that the universal solution can be regarded as pure gauge or the tachyon vacuum solution.