Tuning entanglement by squeezing magnons in anisotropic magnets

TL;DR

This paper theoretically investigates how entanglement between spins in anisotropic magnets can be controlled and tuned using external magnetic fields and anisotropies, revealing potential for quantum information applications.

Contribution

It introduces a model for entanglement control in magnetic materials via squeezing magnons, highlighting the tunability and discontinuous changes in entanglement.

Findings

Entanglement exists in thermodynamic equilibrium in magnetic materials.

External fields and anisotropies can control the amount of entanglement.

Entanglement can exhibit discontinuous jumps as magnetic field varies.

Abstract

We theoretically study the entanglement between two arbitrary spins in a magnetic material, where magnons naturally form a general squeezed coherent state, in the presence of an applied magnetic field and axial anisotropies. Employing concurrence as a measure of entanglement, we demonstrate that spins are generally entangled in thermodynamic equilibrium, with the amount of entanglement controlled by the external fields and anisotropies. As a result, the magnetic medium can serve as a resource to store and process quantum information. We, furthermore, show that the entanglement can jump discontinuously when decreasing the applied magnetic field. This tunable entanglement can be potentially used as an efficient switch in quantum-information processing tasks.