Excision of Singularities by Stringy Domain Walls

TL;DR

This paper explores how stringy mechanisms, specifically the enhancon, can resolve naked singularities in supersymmetric domain wall solutions by utilizing Calabi-Yau cycle collapse and gauge symmetry enhancement.

Contribution

It demonstrates a method to excise singularities in supergravity solutions using the enhancon mechanism within the context of domain walls and Calabi-Yau moduli space.

Findings

The second domain wall coincides with the Calabi-Yau cycle collapse point.

The enhancon mechanism effectively removes the naked singularity.

The physics relates to R -> 1/R duality in heterotic string theory.

Abstract

We study supersymmetric domain walls on S_1/Z_2 orbifolds. The supergravity solutions in the bulk are given by the attractor equation associated with Calabi-Yau spaces and have a naked space-time singularity at some |y_s|. 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 |y_c| which happens before and at a finite distance from the space-time singularity. In our example with three Kahler moduli the second wall is at the end of the moduli space at |y_c| where also the enhancement of SU(2) gauge symmetry takes place so that |y_e|=|y_c|< |y_s|. The physics of the excision of a naked singularity via the enhancon in the context of domain wall has an interpretation on the heterotic side related to R -> 1/R duality. The position of the enhancon is given by the equation R(|y_e|)=1.