Hydrodynamics of quantum spin liquids

TL;DR

This paper explores how emergent gauge fields and symmetries in quantum spin liquids influence their hydrodynamic behavior, revealing additional modes and a diffusive regime for the internal gauge field.

Contribution

It analyzes the hydrodynamics of two specific quantum spin liquids, highlighting the role of emergent gauge fields and symmetries in their low-energy dynamics.

Findings

Emergent gauge fields lead to new hydrodynamic modes.

Identification of a diffusive regime for the internal U(1) gauge field.

Enhanced global symmetries affect low-energy hydrodynamics.

Abstract

Quantum spin liquids are topological states of matter that arise in frustrated quantum magnets at low temperatures. At low energies, such states exhibit emergent gauge fields and fractionalized quasiparticles and can also possess enhanced global symmetries compared to their parent microscopic Hamiltonians. We study the consequences of this emergent gauge and symmetry structure for the hydrodynamics of quantum spin liquids. Specifically, we analyze two cases, the $U(1)$ spin liquid with a Fermi surface and the $SU(4)$-symmetric "algebraic" spin liquid. We show that the emergent degrees of freedom in the spin liquid phase lead to a variety of additional hydrodynamic modes compared to the high-temperature paramagnetic phase. We identify a hydrodynamic regime for the internal $U(1)$ gauge field common to both states, characterized by slow diffusion of the internal transverse photon.