Spin dynamics of the anisotropic spin-1 antiferromagnetic chain at finite magnetic fields

TL;DR

This study explores the complex phase diagram and dynamic properties of an anisotropic spin-1 antiferromagnetic chain under magnetic fields using quantum Monte Carlo simulations.

Contribution

It provides the first comprehensive phase diagram and dynamic structure factor analysis for the model with combined anisotropy and magnetic fields.

Findings

Identified Ne9el, Haldane, Luttinger liquid, and large anisotropy phases.

Observed sharp massive modes and multi-particle continua in the dynamic structure factor.

Results are consistent with existing analytic and numerical studies in special cases.

Abstract

We present results of a study of the antiferromagnetic spin-1 chain, subject to the simultaneous presence of single-ion anisotropy and external magnetic fields. Using quantum Monte-Carlo based on the stochastic series expansion method we first uncover a rich quantum phase diagram comprising N\'eel, Haldane, Luttinger liquid, and large anisotropy phases. Second, we scan across this phase diagram over a wide range of parameters, evaluating the transverse dynamic structure factor, which we show to exhibit sharp massive modes, as well as multi particle continua. For vanishing anisotropy and fields, comparison with existing results from other analytic and numerical approaches shows convincing consistency.