Chern character and Fermi point
Abstract
This paper expresses the Chern character for topological K-theory based on the formulation of the family of Fredholm operators, by using the points at which the Fredholm operator becomes singular (Fermi points). In particular, we explain that the odd Chern character can be thought of as a generalization of the spectral flow. As applications, we give elementary proofs of the evenness of the edge index and the bulk-edge correspondence for four-dimensional topological insulators with time-reversal symmetry of Altland–Zirnbauer class AI.
Fields of Study & Subjects
Topological Materials and Phenomena
Quantum many-body systems
Spectral Theory in Mathematical Physics
Publication details
- Journal / source
- Journal of Mathematical Physics
- Volume
- 67
- Issue
- 4
- Publication date
- 1 April 2026
- Language
- EN