We consider cycles for graded -algebras (Real -algebras) which are compatible with the -structure and the real structure. Their characters are cyclic cocycles. We define a Connes type pairing between such characters and elements of the van Daele -groups of the -algebra and its real subalgebra. This pairing vanishes on elements of finite order. We define a second type of pairing between characters and -group elements which is derived from a unital inclusion of -algebras. It is potentially non-trivial on elements of order two and torsion valued. Such torsion valued pairings yield topological invariants for insulators. The two-dimensional Kane-Mele and the three-dimensional Fu-Kane-Mele strong invariant are special cases of torsion valued pairings. We compute the pairings for a simple class of periodic models and establish structural results for two dimensional aperiodic models with odd time reversal invariance.

生成讲解博客的中文版本

生成AI智能校验的中文版本