Prof. Ken Shiozaki gave a seminar about adiabatic cycles of quantum spin systems. Topological phases of matter without ground state degeneracy are known as inevitable phases. In the literature, their topological properties have been well-studied in free-fermion and many-body systems. The speaker started with the transverse-field Ising model and the Rice-Mele model to demonstrate the pumping of the 1D chain in an adiabatic cycle. He then generalized the concept to cover broader systems, including general spatial dimensions and generic models with any onsite symmetry, such as time-reversal, Z2 Ising, and U(1). He demonstrated that one can classify adiabatic cycles of a spin model, which can be characterized by a Z2 topological invariant. This talk showed that symmetry-protected topological phases emerge by performing an adiabatic cycle.

Reported by Chen-Hsuan Hsu (YITP, Kyoto University)