The Equations of Generalised Hydrodynamics and Their Unusual Diffusive Corrections - Lecture 2

This lecture from King's College London's Benjamin Doyon explores the hydrodynamics of one-dimensional many-body integrable models as part of Harvard CMSA's program on Classical, quantum, and probabilistic integrable systems. Discover the equations of "generalised hydrodynamics" at the Euler scale, including their dependence on asymptotic state content and two-body scattering shift, their Hamiltonian structure, exact solutions, and absence of shocks. Learn why integrable models belong to "linearly degenerate systems" that lack superdiffusion, and understand how diffusive corrections to Euler equations aren't governed by standard derivative expansion but by long-range correlations from Euler-scale fluctuation theory. Examine the theory of deterministically transported initial fluctuations and explore the conjecture that integrable systems show no emergent stochasticity at any hydrodynamic scale once long-range correlations are accounted for.