Gauge Invariance and Tachyon Condensation in Open String Field Theory

TL;DR

This paper investigates gauge invariance in open string field theory, demonstrating that certain singularities are gauge artifacts and exploring methods to analyze tachyon condensation without fixing a specific gauge.

Contribution

It introduces a level truncation approach to determine the validity region of Feynman-Siegel gauge and addresses tachyon potential analysis without gauge fixing.

Findings

Feynman-Siegel gauge validity region can be accurately determined

Singularities in the tachyon potential are gauge artifacts

Stable vacuum can be studied without fixing Feynman-Siegel gauge

Abstract

The gauge invariance of open string field theory is considered from the point of view of level truncation, and applications to the tachyon condensation problem are discussed. We show that the region of validity of Feynman-Siegel gauge can be accurately determined using the level truncation method. We then show that singularities previously found in the tachyon effective potential are gauge artifacts arising from the boundary of the region of validity of Feynman-Siegel gauge. The problem of finding the stable vacuum and tachyon potential without fixing Feynman-Siegel gauge is addressed.