Mathematics of magic angles for bilayer graphene

Date: 
Friday, April 16, 2021 - 3:00pm
Location: 
Zoom
Speaker: 
Maciej Zworski

Abstract: Magic angles are a hot topic in condensed matter physics: when two sheets of graphene are twisted by those angles the resulting material is superconducting. I will present a very simple operator whose spectral properties are thought to determine which angles are magical. It comes from a recent PR Letter by Tarnopolsky--Kruchkov--Vishwanath. The mathematics behind this is an elementary blend of representation theory (of the Heisenberg group in characteristic three), Jacobi theta functions and spectral instability of non-self-adjoint operators (involving Hörmander's bracket condition in a very simple setting). The results will be illustrated by colourful numerics which suggest some open problems (joint work with S Becker, M Embree and J Wittsten).

Please access the talk through the Research Seminars page ( https://researchseminars.org/seminar/MO_Analysis ); you will need to register for a free account. If you have any difficulty, please contact Samuel Walsh (walshsa@missouri.edu).