Super-diffusion in one-dimensional quantum lattice models

TL;DR

This paper investigates super-diffusive transport phenomena in one-dimensional quantum lattice models, deriving bounds on diffusion constants and revealing super-diffusive behavior in certain integrable models at finite temperature.

Contribution

It introduces an analytic method to bound diffusion constants and uncovers super-diffusive transport in specific strongly correlated models at half filling.

Findings

Diverging spin and charge diffusion constants in several models

Analytic lower bounds on diffusion constants derived from hydrodynamics

Evidence of super-diffusive transport in isotropic models at finite temperature

Abstract

We identify a class of one-dimensional spin and fermionic lattice models which display diverging spin and charge diffusion constants, including several paradigmatic models of exactly solvable strongly correlated many-body dynamics such as the isotropic Heisenberg spin chains, the Fermi-Hubbard model, and the t-J model at the integrable point. Using the hydrodynamic transport theory, we derive an analytic lower bound on the spin and charge diffusion constants by calculating the curvature of the corresponding Drude weights at half filling, and demonstrate that for certain lattice models with isotropic interactions some of the Noether charges exhibit super-diffusive transport at finite temperature and half filling.