Excision of singularities by stringy domain walls

Abstract

We study supersymmetric domain walls on S1/Z2 orbifolds. The supergravity solutions in the bulk are given by the attractor equation associated with Calabi–Yau (CY) spaces and have a naked space–time singularity at some |ys|. We are looking for possibilities to cut off this singularity with the second wall by a stringy mechanism. We use the collapse of the CY cycle at |yc| which happens before and at a finite distance from the space–time singularity. In our example with three Kähler moduli the second wall is at the end of the moduli space at |yc| where also the enhancement of SU(2) gauge symmetry takes place so that |ye| = |yc|<|ys|. The physics of the excision of a naked singularity via the enhançon in the context of domain wall has an interpretation on the heterotic side related to R-->1/R duality. The position of the enhançon is given by the equation R(|ye|) = 1.