Séminaire
The concept of topologically-protected transport along the edge of physical systems was born three decades ago in the context of quantum Hall electronics. Waves are protected from disorder and backscattering when emerging at the boundary separating bulk materials characterized by different topological invariants. These invariants are integers characterizing singularities in families of waves, and can be related to the number of unidirectional edge waves propagating in the system. Physicists realized recently that topological protection applies to virtually all areas of physics from photonics, to cold atoms, to classical mechanical systems, and have related these properties to the presence of broken discrete symmetries. However the interplay between discrete symmetries and topology have so far played little role in thinking about the fluid dynamics of oceans and atmospheres. We show that, as a consequence of the rotation of the Earth that breaks time reversal symmetry, equatorially trapped Kelvin and Yanai waves have a topological origin, manifesting as edge modes in rotating shallow water flows.
bruno.deremble@ens.fr