5月31日（水）に，立命館大学談話会を以下の要領で対面とzoomのハイブリッド形式で開催いたします．
講演者はBoras University / 立命館大学のJens Wittsten氏です．
オンラインから参加をご希望の方は以下のリンクから登録を行なってください．
https://ritsumei-ac-jp.zoom.us/meeting/register/tJArdemgpzwqH9KBW7xv7_OR46GNfchaxUhK
日時：2023年5月31日（水）16:30-17:20
場所：立命館大学BKCキャンパス・ウエストウイング6階談話会室/オンライン（zoom）
講演者: Jens Wittsten氏（Boras University / 立命館大学）
タイトル: Mathematics of magic angles for twisted bilayer graphene
タイトル: Mathematics of magic angles for twisted bilayer graphene
アブストラクト:
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 Physical Review Letter by Tarnopolsky–Kruchkov–Vishwanath. The mathematics behind this is a 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 simple setting). The results will be illustrated by colourful numerics which suggest some open problems. This is joint work with S. Becker, M. Embree, and M. Zworski.
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