Nonreciprocal entanglement in cavity-magnon optomechanics

TL;DR

This paper proposes a method to achieve nonreciprocal entanglement among magnons, photons, and phonons in a hybrid cavity-magnon optomechanical system using the magnon Kerr effect, tunable via magnetic fields and temperature.

Contribution

It introduces a novel approach to realize nonreciprocal entanglement leveraging the magnon Kerr effect in cavity-magnon systems, enabling control over nonreciprocity and entanglement.

Findings

Nonreciprocal bipartite and tripartite entanglements can be achieved.

Nonreciprocity can be switched on and off by system parameters.

Temperature influences the nonreciprocal behavior.

Abstract

Cavity optomechanics, a promising platform to investigate macroscopic quantum effects, has been widely used to study nonreciprocal entanglement with Sagnec effect. Here we propose an alternative way to realize nonreciprocal entanglemment among magnons, photons, and phonons in a hybrid cavity-magnon optomechanics, where magnon Kerr effect is used. We show that the Kerr effect gives rise to a magnon frequency shift and an additional two-magnon effect. Both of them can be tuned from positive to negative via tuning the magectic field direction, leading to nonreciprocity. By tuning system parameters such as magnon frequency detuning or the coefficient of the two-magnon effect, bipartite and tripartite entanglements can be nonreciprocally enhanced. By further studying the defined bidirectional contrast ratio, we find that nonreciprocity in our system can be switch on and off, and can be engineered by the bath temperature. Our proposal not only provides a potential path to demonstrate nonreciprocal entanglement with the magnon Kerr effect, but also opens a direction to engineer and design diverse nonreciprocal devices in hybrid cavity-magnon optomechanics with nonlinear effects.