Speaker
Description
The tertiary invariant is a recently introduced pairing between two-dimensional minimally supersymmetric field theories, motivated by topological modular forms. We evaluate this invariant directly from its definition for the sigma model on Sp(2) with unit H-flux paired with the internal theory of the ten-dimensional non-supersymmetric tachyon-free heterotic string, as well as for the sigma model on SU(3) with unit H-flux paired with the near-horizon theory of a non-supersymmetric heterotic 6-brane. We obtain nonzero values of orders three and two for the two pairings, respectively. The former determines the discrete topological term of the heterotic string theory, while the latter provides evidence for the topological stability of the 6-brane. This talk is based on ongoing joint work with Kazuya Yonekura.