Domain wall dynamics in integrable and chaotic spin-1/2 chains

TL;DR

This study investigates how spin-1/2 chains evolve over time in both integrable and chaotic regimes, revealing a link between eigenstate delocalization and spin transport in integrable systems, but not in chaotic ones.

Contribution

It demonstrates a monotonic relationship between eigenstate delocalization and spin dynamics in integrable chains, contrasting with the behavior in chaotic models.

Findings

Delocalization correlates with increased spin current in integrable systems.

Chaotic models show a loss of the correlation between delocalization and spin dynamics.

Eigenstate properties influence transport behavior differently in integrable and chaotic regimes.

Abstract

We study the time evolution of correlation functions, spin current, and local magnetization in an isolated spin-1/2 chain initially prepared in a sharp domain wall state. The results are compared with the level of spatial delocalization of the eigenstates of the system which is measured using the inverse participation ratio. Both integrable and non-integrable regimes are considered. Non-integrability is introduced to the integrable Hamiltonian with nearest neighbor couplings by adding a single site impurity field or by adding next-nearest-neighbor couplings. A monotonic correspondence between the enhancement of the level of delocalization, spin current and magnetization dynamics occurs in the integrable domain. This correspondence is however lost for chaotic models with weak Ising interactions.