Magnetization transport in spin ladders and next-nearest-neighbor chains

TL;DR

This paper investigates magnetization transport in various spin ladder and chain systems at high temperatures, revealing ballistic, anomalous, and diffusive behaviors depending on system integrability and magnetization sectors.

Contribution

It provides analytical and numerical insights into the transport regimes of spin ladders and chains, highlighting differences between integrable and chaotic systems.

Findings

Ballistic transport in integrable ladder sectors with nonzero magnetization

Anomalous transport at zero magnetization in integrable systems

Diffusive transport in chaotic Heisenberg ladders and chains

Abstract

We study magnetization transport at high temperatures in several spin ladder systems as well as in next-nearest-neighbor coupled spin chains. In the integrable ladder considered we analytically show that the transport is ballistic in sectors with nonzero average magnetization, while numerical simulations of a nonequilibrium stationary setting indicate an anomalous transport in the zero magnetization (half-filling) sector. For other systems, isotropic Heisenberg ladder and spin chains, showing eigenlevel repulsion typical of quantum chaotic systems, numerical simulations indicate diffusive transport.