Kinks of open superstring field theory

TL;DR

This paper constructs approximate kink solutions in supersymmetric open string field theory, revealing insights into brane decay and tunneling phenomena, with results closely matching theoretical expectations.

Contribution

It introduces a method to derive approximate kink solutions considering non-local operators, including new duplication formulae for incomplete gamma functions.

Findings

Time kink acts as an instanton with tunneling probability

Spatial kink models D9-brane decay into D8-brane

Calculated brane tension ratio closely matches expected value

Abstract

We construct approximate kink solutions of supersymmetric open string field theory at lowest level when non-local operators in the tachyon effective action are fully taken into account. To this purpose we derive two duplication formulae for products of incomplete gamma functions, which determine the level of approximation of the solutions. The time kink is an instanton of the Euclidean theory with a well-defined tunneling probability. The spatial kink solution represents an unstable D9-brane decaying into a stable D8-brane. We calculate the ratio of the brane tensions, which almost exactly reproduces the expected value.