Asymmetric orbifolds with vanishing one-loop vacuum energy

TL;DR

This paper systematically classifies non-supersymmetric type II toroidal asymmetric orbifolds with vanishing one-loop vacuum energy, highlighting models with potential higher-loop stability.

Contribution

It provides a full classification of such orbifolds with finite Abelian point groups, including detailed constructions and examples with non-Abelian point groups.

Findings

Classification limited to $ ext{Z}_k imes ext{Z}_k$ point groups with k=2,3,4.

Constructed explicit models with vanishing one-loop vacuum energy.

Some models may maintain cancellation at higher loops.

Abstract

We present a systematic study of non-supersymmetric type II toroidal asymmetric orbifolds with vanishing vacuum energy at one-loop in string perturbation theory. These are engineered through the conservation of a supercharge-like operator in each individual sector in the orbifold sum, despite the overall explicit breaking of spacetime SUSY. We provide a full classification of such orbifolds with finite Abelian point-group, which can only admit $\mathbb{Z}_k \times \mathbb{Z}_k$ point group with $k=2,3,4$. We present detailed constructions, alongside other examples with non-Abelian point group. For some of these models, it is possible that this cancellation persists at higher loops.