Worldsheet Instanton Corrections to the Kaluza-Klein Monopole

TL;DR

This paper demonstrates that worldsheet instantons induce localization effects in the geometry of the Kaluza-Klein monopole, revealing new quantum corrections in string theory related to winding modes.

Contribution

It introduces a gauged linear sigma model description of the Kaluza-Klein monopole and shows how instantons lead to geometric corrections associated with winding space localization.

Findings

Worldsheet instantons cause localization in winding space.

Corrections modify the monopole's geometry.

Localization can be probed by winding strings.

Abstract

The Kaluza-Klein monopole is a well known object in both gravity and string theory, related by T-duality to a "smeared" NS5-brane which retains the isometry around the duality circle. As the true NS5-brane solution is localized at a point on the circle, duality implies that the Kaluza-Klein monopole should show some corresponding behavior. In this paper, we express the Kaluza-Klein monopole as a gauged linear sigma model in two dimensions and show that worldsheet instantons give corrections to its geometry. These corrections can be understood as a localization in "winding space" which could be probed by strings with winding charge around the circle.