SFB TRR 352 Mathematics of Many-Body Quantum Systems and Their Collective Phenomena

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Talk by Prof. Dr. Sven Bachmann


On Tuesday, July 9, 2024, 4.15 pm, Prof. Dr. Sven Bachmann (UBC Vancouver) will give a talk on "A new bulk Z_2 invariant for interacting phases" at TUM Garching.

Abstract: The stability of topological indices of condensed matter systems in the presence of interactions is not expected to hold universally. In this colloquium, I will first discuss the mathematical setup of the classification of interacting phases. I will then focus on a new Z_2-valued index for time-reversal invariant interacting fermions on infinite lattices and prove its topological stability. I will show that it generalizes the well-known Fu-Kane-Mele index of topological insulators, thereby proving its stability under large perturbations. This is joint work with Alex Bols and Mahsa Rahnama.