Open String Amplitudes in Various Gauges

TL;DR

This paper explores different gauge choices in open string theory, demonstrating that a modified Schnabl gauge simplifies off-shell amplitude calculations for both bosonic and superstring cases.

Contribution

It introduces a modified Schnabl gauge that significantly simplifies the computation of off-shell amplitudes in open string theory.

Findings

Modified Schnabl gauge reduces computational complexity

Explicit off-shell amplitude calculations in superstring theory

Comparison showing simplification over original gauge

Abstract

Recently, Schnabl constructed the analytic solution of the open string tachyon. Subsequently, the absence of the physical states at the vacuum was proved. The development relies heavily on the use of the gauge condition different from the ordinary one. It was shown that the choice of gauge simplifies the analysis drastically. When we perform the calculation of the amplitudes in Schnabl gauge, we find that the off-shell amplitudes of the Schnabl gauge is still very complicated. In this paper, we propose the use of the propagator in the modified Schnabl gauge and show that this modified use of the Schnabl gauge simplifies the computation of the off-shell amplitudes drastically. We also compute the amplitudes of open superstring in this gauge.