Abstract:
Several atmospheric and oceanic waves are known to be trapped around the Earth's equator. Strikingly enough, two of them (the so-called Kelvin and Yanai waves) can only propagate eastward. This remarkable uni-directional behaviour is analogous to those of chiral boundary states in certain topological insulators, called Chern insulators, whose quantum Hall effect is the original representative. Beyond this analogy, I will show that the solutions of the shallow water model, commonly used to describe ocean and atmospheric dynamics over large distances, indeed carry a topological property that is quantified by a first Chern number, in agreement with the existence of two unidirectional modes.
Ref: P. Delplace, B. Marston and A. Venaille, Science 358, 1075 (2017)
Biography:
Pierre Delplace works on topological properties of matter and waves. He received his B.S in physics from the Université Paris 7 Denis Diderot in 2005, and his Ph.D. in theoretical condensed matter from Université Paris-Sud in 2010. After spending five years at Geneva University as a Post-doc working in mesoscopic physics and topological insulators, he came back to France with a grant from the @RAction national programme for high level researchers. He got a permanent position in 2015 as a CNRS researcher (French National Center for Scientific Research) and works at the Ecole Normale Supérieure in Lyon (France). He is currently visiting ECNU for two weeks teaching as part of the exchange programme between ECNU and ENS.
Seminar by the NYU-ECNU Institute of Mathematical Sciences at NYU Shanghai