A Monopole Solution in open String Theory

TL;DR

This paper finds an exact monopole solution in open string theory in four dimensions by coupling massless modes and tachyons, revealing a non-trivial spacetime configuration with quantized tachyon masses.

Contribution

It presents an exact monopole solution in open string theory combining WZW and Liouville models within the sigma model framework.

Findings

Exact monopole solution in open string theory.

Tachyon masses are quantized and vanish at specific central charge.

Solution interpreted as a monopole in non-trivial spacetime.

Abstract

We investigate a solution of the Weyl invariance conditions in open string theory in 4 dimensions. In the closed string sector this solution is a combination of the SU(2) Wess--Zumino--Witten model and a Liouville theory. The investigation is carried out in the $\sigma$ model approach where we have coupled all massless modes (especially an abelian gauge field via the boundary) and tachyon fields. Neglecting all higher derivatives in the field strength we get an exact result which can be interpreted as a monopole configuration living in non--trivial space time. The masses of both tachyon fields are quantized by $c_{wzw}$ and vanish for $c_{wzw} = 1$.