Physical realization and possible identification of topological excitations in quantum Heisenberg ferromagnet on lattice

TL;DR

This paper investigates topological excitations, specifically quantum vortices, in a 2D quantum Heisenberg ferromagnet, highlighting the role of the Wess-Zumino term in identifying and characterizing these excitations.

Contribution

It introduces a novel formalism for constructing quantum vortices in the Heisenberg ferromagnet, emphasizing the significance of the Wess-Zumino term for vortex identification.

Findings

Wess-Zumino term can identify a large class of vortices

Odd topological charge excitations show self-similar internal charge patterns

Distinct formalism from conventional vortex construction methods

Abstract

Physical configurations corresponding to topological excitations present in the XY limit of a quantum spin 1/2 Heisenberg ferromagnet, are investigated on a two dimensional square lattice. Quantum vortices(anti-vortices) are constructed in terms of terms of coherent spin field components and the crucial role of the associated Wess-Zumino term is highlighted. It is shown that this term can identify a large class of vortices(anti-vortices). In particular the excitations with odd topological charge belonging to this class, are found to exhibit a self-similar pattern regarding the internal charge distribution. Our formalism is distinctly different from the coventional approach for the construction of quantum vortices(anti-vortices).