Title: “Hydrodynamic Fluctuations in Spin Chains and QFTs”
Abstract:
Hydrodynamics – broadly understood as the late-time dynamics of slow excitations – is distinguished by its sparing assumption: thermalization. Its applications are therefore widespread. This talk will focus on consequences of stochastic fluctuations of these slow excitations. When such fluctuations are irrelevant, hydrodynamics serves as a controlled EFT of thermalizing systems: I will show how this EFT can be used to resolve a recent puzzle in the thermalization of SU(2) spin chains, and how it leads to a surprising prediction of a “diffuson cascade”. When fluctuations are strong, diffusion breaks down and is typically replaced by dissipation in the KPZ universality class. I will discuss how this applies to 2d QFTs and the edges of quantum Hall systems.
Slides: