Singularities and closed time-like curves in type IIB 1/2 BPS geometries

TL;DR

This paper analyzes the moduli space of certain IIB supergravity solutions, classifying their singularities and exploring the implications for dual CFT descriptions and potential chronology protection.

Contribution

It classifies solutions into three classes, proves that null singularities are equivalent to non-singular solutions, and discusses the dual CFT correspondence and chronology protection.

Findings

Solutions fall into non-singular, null-singular, and time machine classes.

Null singularities are equivalent to non-singular solutions.

AdS/CFT correspondence applies only to non-singular solutions.

Abstract

We study in detail the moduli space of solutions discovered in LLM relaxing the constraint that guarantees the absence of singularities. The solutions fall into three classes, non-singular, null-singular and time machines with a time-like naked singularity. We study the general features of these metrics and prove that there are actually just two generic classes of space-times - those with null singularities are in the same class as the non-singular metrics. AdS/CFT seems to provide a dual description only for the first of these two types of space-time in terms of a unitary CFT indicating the possible existence of a chronology protection mechanism for this class of geometries.