Modulated periodic entanglement of magnons in a ferromagnet

Yunxia Ping, Bo Zhang, Ze Cheng +1 more

L.S. Lima

Yuhong He, Jiajia Wang, Li-zhen Jiang +2 more

Abstract We show how robust magnon-magnon (or photon-magnon) entanglement and asymmetric quantum steering can be achieved in a nonlinear cavity-magnon system composed of a microwave cavity and two yttrium-iron-garnet (YIG) spheres, which are each driven by external microwave driving fields. The self-Kerr nonlinearity (SKN) of two magnons drives this behaviour and we study how two-fold periodically-modulated driving fields influence the system dynamics. We find that beating occurs both in the classical average of the cavity mode and in the entanglement between modes. Moreover, the use of modulated driving fields can enhance the degree of entanglement generated as well as giving rise to asymmetric quantum steering effects that would not otherwise be present. Finally, we show that the entanglement generated this way has improved robustness to thermal noise opening the way to potential applications of magnon-based hybrid systems in quantum information processing and studies of fundamental physics.

A‐Peng Liu, Cheng‐Hua Bai, Qi Guo

ABSTRACT We study a dissipative opto‐magnomechanical system implemented using a yttrium iron garnet (YIG) sphere, which supports a magnon mode and two optical whispering‐gallery modes coupled via magnon‐induced Brillouin scattering. Besides, another mechanical mode is considered, which interacts with the optical and magnon modes through radiation pressure and magnetostriction, respectively. This hybrid system is under combined optical driving for the optical modes and microwave driving for the magnon mode and the amplitude of the microwave field is periodically modulated. We apply different parametric approximations by strongly driving one of the optical modes for preparing squeezing and entangled states, respectively. When the classical driving fields are red‐detuned, strong mechanical squeezing beyond the 3‐dB limit is achieved, along with simultaneous squeezing of all three modes. In addition, when the microwave field is red‐detuned and the optical laser is blue‐detuned, significant bipartite and tripartite entanglement is generated. These quantum entanglements are markedly enhanced by periodic modulation compared to the non‐modulated case. The proposed configurations exhibit strong robustness against system dissipation and environmental temperature, suggesting their potential as quantum resources for metrology and information processing applications.

Clement H. Wong, Ari Mizel

Qi Guo, Jinglan Liu, Cheng‐Hua Bai +3 more

We propose schemes for generating quantum squeezing and enhancing entanglement in an opto-magnomechanical configuration by periodically modulating the driving field. The system consists of an optical cavity and a ferrimagnetic yttrium-iron-garnet micro-bridge supporting a magnon mode and a mechanical vibration mode, in which the mechanical mode couples to the optical mode and the magnon mode via radiation pressure and magnetostrictive interaction, respectively. The optical mode and the magnon mode are driven by classical fields, and the amplitude of the laser field driving the optical cavity is periodically modulated. We find that when the classical fields are red-detuned and their anti-Stokes sidebands scattered by the mechanical motion resonate with the corresponding driven modes, all the modes in the system will be squeezed simultaneously, and the mechanical squeezing can exceed the 3-dB limit. Furthermore, when the driving laser field is red-detuned and the microwave field is blue-detuned, both the bipartite and tripartite entanglements will be generated, and compared to the case without periodical modulation, the entanglements are significantly enhanced. We also show that the schemes have strong robustness against the system dissipations and environmental temperature. Our schemes may provide efficient quantum resources for quantum precision measurement and quantum information processing.