Finite-temperature spin diffusion in the two-dimensional XY model

TL;DR

This study combines theoretical high-temperature expansion and experimental quantum simulation to accurately measure and validate spin diffusion in the 2D XY model, advancing understanding of spin transport in higher dimensions.

Contribution

It introduces a novel combined approach using high-temperature expansion and optical lattice experiments to quantify spin diffusion in the 2D XY model.

Findings

Excellent agreement between theory and experiment for spin diffusion constants.

Breakthrough in understanding spin transport beyond one dimension.

Theoretical predictions for future experiments on spin conductivity and anisotropy effects.

Abstract

We present a combined theory-experiment study to quantify spin diffusion in the square lattice quantum spin-1/2 XY model at finite temperature. On the theory side, we leverage a recently developed dynamical high-temperature expansion method to faithfully capture the long spatiotemporal scales of the hydrodynamic regime. Experimental results are obtained from an optical lattice hard-core boson quantum simulator. The excellent agreement of spin diffusion constants marks a breakthrough in spin-transport beyond one dimension and for the quantitative validation of state-of-the-art quantum simulation platforms. We also provide theory predictions for future experiments on dynamic spin conductivity or anisotropy-induced integrability breaking.