Nonreciprocal multipartite entanglement induced by Kerr nonlinearity

Abstract

We present a theoretical scheme for the generation of nonreciprocal multipartite entanglement in a two-mode cavity magnomechanical system, consisting of two cross-microwave cavities having a yttrium-iron-garnet (YIG) sphere, which is coupled through magnetic dipole interaction. Our results show that the self-Kerr effect of magnon (which depends on the intensity of the magnons) can significantly enhance multipartite entanglement, which turns out to be nonreciprocal when the magnetic field is tuned along different crystallographic axes. This is due to the frequency shift on the magnons (YIG sphere), which depends upon the magnetic field’s direction. Interestingly, the degree of nonreciprocity of bipartite entanglements depends upon a careful optimal choice of system parameters like normalized cavity detunings, bipartite nonlinear index \(\Delta E_{K}\), self-Kerr coefficient, and effective magnomechanical coupling rate G. In addition to bipartite entanglement, we also present the idea of a bidirectional contrast ratio, which quantifies the nonreciprocity in tripartite entanglements. Our present theoretical proposal for nonreciprocity in multipartite entanglement may find applications in diverse engineering nonreciprocal devices. Furthermore, the current scheme might enhance the functionality of magnonic devices, and improve sensing capabilities.