Modular Invariance in Superstring on Calabi-Yau n-fold with A-D-E Singularity

TL;DR

This paper analyzes superstring theory on Calabi-Yau n-folds with A-D-E singularities, computing modular invariant partition functions that confirm supersymmetry and classify singularities.

Contribution

It provides explicit modular invariant partition functions for superstrings on Calabi-Yau n-folds with A-D-E singularities, extending the understanding of their holographic duals.

Findings

Partition functions are modular invariant and vanish due to theta identities.

Results are consistent with space-time supersymmetry.

Classifies singularities via A-D-E series in superstring backgrounds.

Abstract

We study the type II superstring theory on the background $\br^{d-1,1}\times X_n$, where $X_n$ is a Calabi-Yau $n$-fold ($2n+d=10$) with an isolated singularity, by making use of the holographically dual description proposed by Giveon-Kutasov-Pelc (hep-th/9907178). We compute the toroidal partition functions for each of the cases $d=6,4,2$, and obtain manifestly modular invariant solutions classified by the standard $A-D-E$ series corresponding to the type of singularities on $X_n$. Partition functions of these modular invariants all vanish due to theta function identities and are consistent with the presence of space-time supersymmetry.