Z3 discrete theta angle in 10D heterotic string theory and Topological Modular Forms

概要

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In this talk we identify a Z3 discrete gravitational theta angle in the non-supersymmetric SO(16) x 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 Z3 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) x SO(16) chiral fermionic SCFT. Based on 2403.08861 with Yuji Tachikawa.