Speaker
Description
Generalized global symmetries provide not only a classification of phases, but also a dynamical organizing principle for nonequilibrium phenomena. In this talk, I will discuss two related developments. First, I will show that Nambu-Goldstone modes associated with ordinary and higher-form symmetries can become unstable in the presence of background fields. Familiar examples include the chiral plasma instability and the instability of a dynamical axion in a background electric field. These instabilities are universally characterized by a symmetry algebra that generalizes the conventional counting rule for Nambu-Goldstone modes. Second, I will discuss the nonlinear evolution of these instabilities. In axion electrodynamics with a topological interaction, the conserved charge associated with a 1-form symmetry drives a self-similar inverse cascade, leading to large-scale coherent structures and the generation of topological linking numbers. These results suggest that generalized symmetries offer a unified framework for understanding unstable collective modes and turbulent inverse cascades.