Studies On Remote Entanglement Between Mechanical Modes In Optomagnonics-mechanical System

Optomechanical systems(OMS)is a system,which is used to explore the interaction between light and matter.A standard Optomechanical system consists of a FabryPerot cavity,which consists of a movable nanomechanical mirror and a fixed optical mirror.Under the pressure of electromagnetic radiation,the photon in the cavity is coupled with the phonon excited by the mechanical vibrator,so it has many novel physical properties.Optomechanical systems have been widely used to explore many physical phenomena in quantum scales,such as optomechanical induced transparency,ground state cooling,quantum squeezing,quantum entanglement,and nonreciprocal photon transmission.Due to the advantages of large spin density,low loss and wide adjustable frequency,magnons are regarded as one of the preferred information carriers.Therefore,there are much numbers of researches about the related physical properties of magnons.Recently,the optomagnonicsmechanical system that includes the Yttrium iron Garnet(YIG ball)in the optomechanical system,has attracted extensive attention.The optomagnonics-mechanical system is a composite system,composed of optical mode,magnetic mode,and phonon mode.In the system,the photon and magnon are coupled by magnon dipole interaction,and the magnon and phonon are coupled by magnetostrictive interaction.The optomagnonics-mechanical system provides an ideal operating platform for realizing the ground state cooling,quantum squeezing and quantum entanglement.However,optomagnonics-mechanical system in practical application will generate thermal noise via the continuous vibration of the mechanical modes.And thermal noise would have a negative effect for the information fidelity of the system.Fortunately,the quantum entanglement between phonons coming from different mechanical mode have an optimistic effect to reduce the thermal noise.Therefore,it is necessary to study entanglement between mechanical modes in optomagnonics-mechanical system.In this paper,we will consider the remote entanglement between mechanical modes in a multi-mode optomagnonics system.The main contents are as follows:1.Firstly,we consider magnon-mechanical entanglement in a rotating three-mode optomagnonics system.By comparing the entanglement properties of the rotating optical magnetic cavity with that of the standard Fabry-Perot cavity,we find that non-reciprocal quantum entanglement can be achieved by adjusting the relevant parameters,i.e.,quantum entanglement is obvious in one direction and weak in the opposite direction.This provides a theoretical scheme for the realization the non-reciprocal entanglement.2.We consider the remote entanglement between two mechanical oscillators in a fourmode optomagnonics system under dual mechanical mode.It is found that the optomechanical coupling can change the entanglement intensity in some specific regions in the original threemode system.What's more,the remote entanglement between the two mechanical modes can be achieves,and the intensity of entanglement can be changed by adjusting the optical force coupling coefficient,magnon-mechanical coupling coefficient,and optomagnon coupling coefficient.