The geometry of null rotation identifications

TL;DR

This paper explores the geometric structure of flat spacetime quotients by null rotations, their supersymmetry properties, and connections to black holes and string theory, including potential singularity resolutions.

Contribution

It provides a detailed analysis of null rotation quotients in flat spacetime and their embedding in String/M-theory, revealing preserved supersymmetries and links to black hole solutions.

Findings

Preserves half of the supersymmetries in String/M-theory embeddings

Connects null rotation quotients to BTZ black holes and supersymmetric waves

Discusses potential resolution of singularities via nullbranes

Abstract

The geometry of flat spacetime modded out by a null rotation (boost+rotation) is analysed. When embedding this quotient spacetime in String/M-theory, it still preserves one half of the original supersymmetries. Its connection with the BTZ black hole, supersymmetric dilatonic waves and one possible resolution of its singularity in terms of nullbranes are also discussed.