Generation of Entanglement and Perfect One-Way EPR Steering via Kerr Nonlinearity in Cavity Magnonics System

A scheme is proposed for generating entanglement and achieving perfect one-way EPR (Einstein-Podolsky-Rosen) steering in a cross-shaped cavity magnonics system via the Kerr effect arising from magnetocrystalline anisotropy. The scheme involves two microwave cavities with distinct quality factors that simultaneously couple to a magnon mode of a macroscopic yttrium-iron-garnet sphere via the magnetic-dipole interaction. It is demonstrated that both the bipartite and tripartite entanglement among the three modes will be generated due to Kerr nonlinearity, and the perfect one-way EPR steering will also be achieved between the cavity with higher quality factor and the magnon mode. Notably, this scheme differs from conventional protocols that produce asymmetric EPR steering by introducing additional unbalanced losses or noises; instead, it can generate and manipulate one-way EPR steering solely by adjusting the detuning between the magnon mode and the microwave drive field. It is also analyzed that the robustness of the entanglement and EPR steering against the dissipation of magnon and environmental temperature. The present scheme may provide a promising platform and an efficient quantum resource for quantum information processing.