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$\mathbb{Z}_3$ Discrete Theta Angle in $10D$ Heterotic String Theory and Topological Modular Forms

组织者

崔嵬 , 徐锋军

演讲者

张昊

时间

2024年04月30日 14:00 至 15:00

地点

A3-1-101

线上

Zoom 787 662 9899 (BIMSA)

摘要

In this talk, we identify a $\mathbb{Z}_3$ discrete gravitational theta angle in the non-supersymmetric $SO(16) \times SO(16)$ heterotic string, which is detected by a $10D$ spacetime manifold that is an $Sp(2)$ group manifold. In the first part, we explain the string theory computation that identifies this $\mathbb{Z}_3$ theta angle, involving non-perturbative anomaly on the instantonic NS5 branes. In the second part, we motivate our endeavor by Stolz-Teichner conjecture which relates $2D (0,1)$ SQFT to Topological modular forms. Our result identifies two generators of torsional classes in TMF of specific degrees by explicit $2D (0,1)$ theories: one begins a $2D (0,1)$ sigma model to $Sp(2)$, the other being the $SO(16) \times SO(16)$ chiral fermionic SCFT. Based on 2403.08861 with Yuji Tachikawa.