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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik

MP 11: Many-body Theory II

MP 11.6: Vortrag

Donnerstag, 21. März 2024, 11:30–11:50, HL 102

Birth quota of non-generic degeneracy points — •Gergo Pinter^1,2, Gyorgy Frank^1,2, Daniel Varjas³, and Andras Palyi^1,2 — ¹Department of Theoretical Physics, Budapest University of Technology and Economics, Hungary — ²MTA-BME Exotic Quantum Phases Group, Budapest University of Technology and Economics, Hungary — ³Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden

Let's think of a Hamiltonian system with a parameter space of dimension three - for example, it can be either the electronic band structure of a crystal or the Hamiltonian of two electrons in a double quantum dot depending on an external magnetic field. The generic degeneracy points of such systems are the Weyl points. For small perturbations the Weyl points are robust, while a non-generic twofold degeneracy point splits into Weyl points. What is the possible number of the Weyl points born from a non-generic degeneracy point? We show a strict upper bound for this number. https://arxiv.org/abs/2202.05825

Keywords: Weyl points; degeneracy; Chern number; electronic band structure; topology