Highly Symmetric Quintic Quotients

TL;DR

This paper classifies symmetries of quotients of the quintic Calabi-Yau threefolds, revealing new symmetric families and singularities, using computational methods to extend previous theoretical work.

Contribution

It provides a comprehensive classification of symmetries of $ ext{Z}_5 imes ext{Z}_5$ quotients of the quintic family, including new symmetric and singular manifolds, with a computational approach.

Findings

Identified families with symmetries $ ext{Z}_4$, $ ext{Dic}_3$, $ ext{Dic}_5$, $ ext{Z}_6$, $ ext{Q}_8$, $ ext{Z}_{10}$.

Discovered singular manifolds with conifold points and curves of singularities.

Developed methods applicable to other CICY quotient symmetries.

Abstract

The quintic family must be the most studied family of Calabi-Yau threefolds. Particularly symmetric members of this family are known to admit quotients by freely acting symmetries isomorphic to $\mathbb{Z}_5 \times \mathbb{Z}_5$. The corresponding quotient manifolds may themselves be symmetric. That is, they may admit symmetries that descend from the symmetries that the manifold enjoys before the quotient is taken. The formalism for identifying these symmetries was given a long time ago by Witten and instances of these symmetric quotients were given also, for the family $\mathbb{P}^7[2, 2, 2, 2]$, by Goodman and Witten. We rework this calculation here, with the benefit of computer assistance, and provide a complete classification. Our motivation is largely to develop methods that apply also to the analysis of quotients of other CICY manifolds, whose symmetries have been classified recently. For the $\mathbb{Z}_5 \times \mathbb{Z}_5$ quotients of the quintic family, our list contains families of smooth manifolds with symmetry $\mathbb{Z}_4$, $\text{Dic}_3$ and $\text{Dic}_5$, families of singular manifolds with four conifold points, with symmetry $\mathbb{Z}_6$ and $\mathbb{Q}_8$, and rigid manifolds, each with at least a curve of singularities, and symmetry $\mathbb{Z}_{10}$. We intend to return to the computation of the symmetries of the quotients of other CICYs elsewhere.