On Twisted Elliptic Genera

We study the twisted elliptic genera associated to the BPS strings in the twisted circle compactification of 6d (1,0) SCFTs. Such objects can arise when the 6d gauge algebra allows outer automorphism. We study several aspects of twisted elliptic genera including twisted elliptic blowup equations, Γ1(N) modular bootstrap and spectral flow symmetry. This is a short summary of the author’s talk at MATRIX Program “2D Supersymmetric Theories and Related Topic”, and based on a joint work with Kimyeong Lee and Xin Wang.