Events

Random scattering of light, e.g., in paint, clouds, and biological tissue, is a common process of both fundamental interest and practical relevance. The interference of multiply scattered waves also leads to remarkable phenomena in mesoscopic physics such as Anderson localization and universal conductance fluctuations. In applications, optical scattering is the main obstacle to imaging or sending information through turbid media.

Irregularly shaped particles with attractive interactions, such as proteins or patchy colloids, are in general frustrated: it is impossible to arrange them in space such that all attractive interactions are simultaneously satisfied. In a dense phase, this implies that any configuration must include defects to the favoured local order.

Topology sheds new light on the emergence of unidirectional edge waves in a variety of physical systems, from condensed matter to artificial lattices. Waves observed in geophysical flows are also robust to perturbations, which suggests a role for topology. We show a topological origin for two celebrated equatorially trapped waves known as Kelvin and Yanai modes, due to the Earth’s rotation that breaks time-reversal symmetry. The non-trivial structure of the bulk Poincare ́ wave modes encoded through the first Chern number of value 2 guarantees existence for these waves.