Entanglement in finite spin rings with noncollinear Ising interaction

TL;DR

This paper explores how noncollinear Ising interactions in finite spin rings influence entanglement, revealing GHZ-like states and controllable quantum correlations via magnetic fields.

Contribution

It introduces models of spin rings with noncollinear Ising interactions and analyzes their entanglement properties, highlighting the role of symmetry and external magnetic fields.

Findings

Ground states exhibit GHZ-like entanglement without magnetic field.

Magnetic fields can switch entanglement from multipartite to pairwise.

Models have point group symmetry instead of translation invariance.

Abstract

We investigate the entanglement properties of finite spin rings, with noncollinear Ising interaction between nearest neighbours. The orientations of the Ising axes are determined either by the spin position within the ring (model A) or by the direction of the bond (model B). In both cases, the considered spin Hamiltonians have a point group symmetry, rather than a translation invariance, as in spin rings with collinear Ising interaction. The ground state of these models exhibit remarkable entanglement properties, resembling GHZ-like states in the absence of an applied magnetic field (model B). Besides, the application of an homogeneous magnetic field allows to modify qualitatively the character of the ground state entanglement, switching from multipartite to pairwise quantum correlations (both models A and B).