This article is cited in 2 papers

Topological excitations in a two-dimensional spin system with high spin $s\ge1$

Yu. N. Bernatskaya, P. I. Holod

National University of Kyiv-Mohyla Academy

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 the exchange interaction. The quantum model is associated with a classical model (the continuous classical analogue) based on a Landau–Lifshitz-like equation, which describes large-scale fluctuations of the mean field. On the other hand, the classical model in the case of spin $s$ is a Hamiltonian system on a coadjoint orbit of the unitary group $SU(2s+1)$. We construct 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, conserving energy.

Keywords: order parameter, mean field, effective Hamiltonian, coadjoint orbit.

DOI: 10.4213/tmf6373

 English version: Theoretical and Mathematical Physics, 2009, 160:1, 878–886

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