Nonreciprocal Photon-Phonon Entanglement in Kerr-Modified Spinning Cavity Magnomechanics

TL;DR

This paper proposes a method to generate nonreciprocal photon-phonon entanglement in cavity magnomechanics, leveraging Kerr and Sagnac effects to achieve asymmetric entanglement with potential applications in nonreciprocal quantum devices.

Contribution

It introduces a novel scheme for magnon-mediated nonreciprocal photon-phonon entanglement using Kerr and Sagnac effects, enhancing entanglement robustness and controllability.

Findings

Nonreciprocal entanglement can be achieved via magnon-phonon swapping.

Magnon Kerr and Sagnac effects significantly enhance entanglement.

Entanglement remains stable at temperatures around 3 K.

Abstract

Cavity magnomechanics has shown great potential in studying macroscopic quantum effects, especially for quantum entanglement, which is a key resource for quantum information science. Here we propose to realize magnon mediated nonreciprocal photon-phonon entanglement, which exhibits asymmetry when opposite magnetic or driving fields are respectively applied to the magnons with the Kerr effect or the photons with the Sagnac effect. We find that the mean magnon number can selectively exhibit nonreciprocal linear or nonlinear (bistable) behavior with the strength of the strong driving field on the cavity. Assisted by this driving field, the magnon-phonon coupling is greatly enhanced, leading to the nonreciprocal photon-phonon entanglement via the swapping interaction between the magnons and photons. This nonreciprocal entanglement can be significantly enhanced with the magnon Kerr and Sagnac effects. Given the available parameters, the nonreciprocal photon-phonon entanglement can be preserved at $\sim3$ K, showing remarkable resilience against the bath temperature. The result reveals that our paper holds promise in developing various nonreciprocal devices with both the magnon Kerr and Sagnac effects in cavity magnomechanics.