Trimming the Tachyon String Field with SU(1,1)

TL;DR

This paper identifies a discrete SU(1,1) symmetry in the tachyon condensate of string field theory, enabling the reduction of the relevant string field to SU(1,1) singlets, which simplifies the analysis of tachyon condensation.

Contribution

It reveals a hidden SU(1,1) symmetry in the tachyon condensate and shows how to trim the string field to SU(1,1) singlets, simplifying the study of tachyon condensation.

Findings

Identification of SU(1,1) symmetry in the tachyon condensate

Reduction of string field to SU(1,1) singlets

Implication for simplifying tachyon condensation analysis

Abstract

A discrete symmetry of the string field tachyon condensate noted by Hata and Shinohara is identified as a discrete subgroup of an SU(1,1) symmetry acting on the ghost coordinates. This symmetry, known from early studies of free gauge invariant string field actions, extends to off-shell interactions only for very restricted kinds of string vertices, among them the associative vertex of cubic string field theory. It follows that the string field relevant for tachyon condensation can be trimmed down to SU(1,1) singlets.