A Non-Supersymmetric Open String Theory and S-Duality

TL;DR

This paper constructs a non-supersymmetric open string theory in ten dimensions, analyzes its spectrum and D-branes, and suggests a possible S-duality relation with bosonic string theory.

Contribution

It introduces a new non-supersymmetric open string model derived from orbifolding and orientifolding, and explores its duality with bosonic string theory.

Findings

The gauge group is SO(32)×SO(32).

The spectrum includes a closed string tachyon and open string tachyons.

Massless excitations of a 1-brane match bosonic string degrees of freedom.

Abstract

A non-supersymmetric ten-dimensional open string theory is constructed as an orbifold of type I string theory, and as an orientifold of the bosonic type B theory. It is purely bosonic, and cancellation of massless tadpoles requires the gauge group to be SO(32)xSO(32). The spectrum of the theory contains a closed string tachyon, and open string tachyons in the (32,32) multiplet. The D-branes of this theory are analyzed, and it is found that the massless excitations of one of the 1-branes coincide with the world-sheet degrees of freedom of the D=26 bosonic string theory compactified on the SO(32) lattice. This suggests that the two theories are related by S-duality.