“Generalized Hydrodynamics” (GHD) stands for a model that describes one-dimensional integrable systems in quantum physics, such as ultra-cold atoms or spin chains. Mathematically, GHD corresponds to nonlinear equations of kinetic type, where the main unknown, statistical distribution function f(t,z,θ), lives phase space which is constituted by position variable z, and “kinetic” θ, actually wave...