Topological excitations in 2D spin system with high spin $s>= 1$

TL;DR

This paper introduces a class of topological excitations in a 2D high-spin quantum Heisenberg model, linking quantum and classical descriptions to reveal stable, shape-changing configurations with fixed topological charges.

Contribution

It constructs and analyzes topological excitations in a high-spin 2D quantum spin system using a classical Landau-Lifshitz analogue on coadjoint orbits, revealing new stable configurations.

Findings

Identified topological excitations with fixed charges

Linked quantum model to classical Landau-Lifshitz equations

Discovered excitations that change shape while preserving energy

Abstract

We construct a class of topological excitations of a mean field in a two-dimensional spin system represented by a quantum Heisenberg model with high powers of exchange interaction. The quantum model is associated with a classical one (the continuous classical analogue) that is based on a Landau-Lifshitz like equation, and describes large-scale fluctuations of the mean field. On the other hand, the classical model is a Hamiltonian system on a coadjoint orbit of the unitary group SU($2s {+} 1$) in the case of spin $s$. We have found a class of mean field configurations that can be interpreted as topological excitations, because they have fixed topological charges. Such excitations change their shapes and grow preserving an energy.