Revisiting toric SU(3) structures

TL;DR

This paper investigates the construction of SU(3) structures on three-dimensional smooth compact toric varieties with even first Chern class, analyzing their parametric freedom and relevance for string compactifications.

Contribution

It demonstrates that all such toric varieties admit SU(3) structures via a systematic method and explores their parametric space and potential for string theory applications.

Findings

Every SCTV admits multiple SU(3) structures.

Parametric choices can match string vacuum requirements.

Metric positivity constrains but does not eliminate structure options.

Abstract

Three-dimensional smooth compact toric varieties (SCTV) admit SU(3) structures, and may thus be relevant for string compactifications, if they have even first Chern class (c1). This condition can be fulfilled by infinitely many SCTVs, including CP3 and CP1 bundles over all two-dimensional SCTVs. We show that as long as c1 is even, toric SU(3) structures can be constructed using a method proposed in arXiv:1005.2194. We perform a systematic study of the parametric freedom of the resulting SU(3) structures, with a particular focus on the metric and the torsion classes. Although metric positivity constrains the SU(3) parameters, we find that every SCTV admits several toric SU(3) structures and that parametric choices can sometimes be made to match requirements of string vacua. We also provide a short review on the constraints that an SU(3) structure must meet to be relevant for four-dimensional, maximally symmetric N=1 or N=0 string vacua.