Uploaded February 2023 | Updated September 2026, 2 weeks ago

---

In this talk I will discuss a Z_2 index associated to quadratic gapped Hamiltonians that describe fermionic systems in the context of self-dual CAR C*-algebras. Concrete examples will be used in order to illustrate the physical relevance of this invariant. I will also present preliminary results of an attempt to extend this invariant to the finite temperature case, which is based on a generalization of the geometric phase to mixed states.
Presented by Andrés Fernando Reyes Lega 23-02-2023