Approximate higher-form symmetries, topological defects, and dynamical phase transitions

TL;DR

This paper develops a systematic framework for effective theories with approximate higher-form symmetries, analyzing their breaking patterns, dualities, and dynamical phase transitions in various condensed matter systems.

Contribution

It introduces a comprehensive approach to modeling weakly broken higher-form symmetries, including dualities and out-of-equilibrium dynamics, applicable to multiple phase transitions.

Findings

Framework describes vortex proliferation and phase transitions.

Hydrodynamic theories capture charge and Goldstone mode relaxation.

Applicable to melting, plasma, spin-ice, superfluid, and superconductor transitions.

Abstract

Higher-form symmetries are a valuable tool for classifying topological phases of matter. However, emergent higher-form symmetries in interacting many-body quantum systems are not typically exact due to the presence of topological defects. In this paper, we develop a systematic framework for building effective theories with approximate higher-form symmetries, i.e. higher-form symmetries that are weakly explicitly broken. We focus on a continuous U(1) q-form symmetry and study various patterns of symmetry breaking. This includes spontaneous or explicit breaking of higher-form symmetries, as well as pseudo-spontaneous symmetry breaking patterns where the higher-form symmetry is both spontaneously and explicitly broken. We uncover a web of dualities between such phases and highlight their role in describing the presence of dynamical higher-form vortices. In order to study the out-of-equilibrium dynamics of these phases of matter, we formulate respective hydrodynamic theories and study the spectra of excitations exhibiting higher-form charge relaxation and Goldstone relaxation effects. We show that our framework is able to describe various phase transitions due to proliferation of vortices or defects. This includes the melting transition in smectic crystals, the plasma phase transition from polarised gases to magnetohydrodynamics, the spin-ice transition, the superfluid to neutral fluid transition and the Meissner effect in superconductors, among many others.