Enhancement of quantum correlations in a cavity–magnon system with feedback control

Abstract

We propose a scheme to generate and enhance the quantum correlations between two magnons separated in two microwave cavities with feedback control of the cavity field. In each cavity, the magnon is coupled to the cavity mode by magnetic dipole interaction, and the interaction between two microwave cavities is realized via linear beam splitter interaction without any nonlinear interaction in the system. We show that the quantum entanglement, as a special quantum correlation, between the two magnons is improved in the system with double-feedback control, and the entanglement is highly robust to temperature. It is always possible to optimize the entanglement by modulating the gain of the other feedback loop if the parameters of one of the feedback loops are given. Also, there is one-way steering between two magnons of the system in the presence of a single feedback loop.