Wave topology brought to the coast
Abstract
Since the pioneering work of Kelvin on Laplace tidal equations, a zoology of trapped waves have been found in the context of coastal dynamics. Among them, the one originally computed by Kelvin plays a particular role, as it is a unidirectional mode filling a frequency gap between different wave bands. The existence of such Kelvin waves is robust to changes in the boundary shape and in changes of the underlying model for the coast. This suggests a topological interpretation that has yet up to now remained elusive. Here we rectify the situation, by taking advantage of a reformulation of the shallow water dynamics that highlights an analogy with the celebrated Haldane model in condensed matter physics. For any profile of bottom topography, the number of modes that transit from one wave band to another in the dispersion relation is predicted by computing a first Chern number describing the topology of complex eigenmodes in a dual, simpler wave problem.
 Publication:

Physical Review Research
 Pub Date:
 October 2021
 DOI:
 10.1103/PhysRevResearch.3.043002
 arXiv:
 arXiv:2011.03440
 Bibcode:
 2021PhRvR...3d3002V
 Keywords:

 Physics  Fluid Dynamics;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Physics  Atmospheric and Oceanic Physics
 EPrint:
 Phys. Rev. Research 3, 043002 (2021)