On parallelisable NS-NS backgrounds

TL;DR

This paper classifies certain supergravity backgrounds with absolute parallelism, identifying seven classes of parallelised Lie groups with various supersymmetry levels, expanding understanding of their geometric and physical properties.

Contribution

It provides a complete classification of non-dilatonic NS-NS backgrounds with absolute parallelism, detailing their geometric structures and supersymmetry preservation.

Findings

Seven classes of backgrounds identified with scalar flat bi-invariant Lorentzian metrics.

Supersymmetry preserved ranges from 16 to 32 supercharges.

Some classes contain moduli, indicating continuous parameters.

Abstract

We classify non-dilatonic NS-NS type II supergravity backgrounds admitting a consistent absolute parallelism. They are all given by parallelised Lie groups admitting scalar flat bi-invariant lorentzian metrics. There are seven different classes, some of them containing moduli. For each class we determine the amount of supersymmetry which is preserved: there are examples with 16, 18, 20, 22, 24, 28 and 32 supersymmetries.