Generating multipartite entanglement is always a popular research field in quantum information processing and quantum optics. In this paper, we propose a scheme to realize all bipartite entanglements and the genuine tripartite entanglement among photon, magnon, and phonon modes in a cavity-magnomechanical system. The center-of-mass motion of a yttrium iron garnet sphere couples to the magnon and constitutes photon-magnon-phonon tripartite interaction. By modulating the detuning between the cavity (magnon) mode and the driven field, we can obtain the optimal photon-phonon entanglement or magnon-phonon entanglement. The genuine tripartite entanglement can be prepared through a suitable detuning. We compare the different entanglement cases with and without effective direct cavity-magnon coupling. The results indicate that the photon-magnon entanglement can be enhanced by the effective cavity-magnon coupling strength, and all bipartite entanglements show greater robustness against the thermal phonon number. This investigation should be useful for phonon-involved multipartite quantum information processing and quantum precision measurement.
Generating multipartite entanglement is always a popular research field in quantum information processing and quantum optics. In this paper, we propose a scheme to realize all bipartite entanglements and the genuine tripartite entanglement among photon, magnon, and phonon modes in a cavity-magnomechanical system. The center-of-mass motion of a yttrium iron garnet sphere couples to the magnon and constitutes photon-magnon-phonon tripartite interaction. By modulating the detuning between the cavity (magnon) mode and the driven field, we can obtain the optimal photon-phonon entanglement or magnon-phonon entanglement. The genuine tripartite entanglement can be prepared through a suitable detuning. We compare the different entanglement cases with and without effective direct cavity-magnon coupling. The results indicate that the photon-magnon entanglement can be enhanced by the effective cavity-magnon coupling strength, and all bipartite entanglements show greater robustness against the thermal phonon number. This investigation should be useful for phonon-involved multipartite quantum information processing and quantum precision measurement.
Abstract We propose to realize bipartite and tripartite entanglements transfer in a cavity magnomechanical system consisting of a microwave cavity with an yttrium iron garnet (YIG) sphere and a silicon-nitride membrane in it. The initial magnon–YIG phonon entanglement and photon-membrane phonon entanglement caused by the magnetostrictive interaction and the optomechanical interaction can be effectively transferred to magnon–membrane phonon entanglement and photon–YIG phonon entanglement. Photon–magnon–YIG phonon and photon–magnon–membrane phonon entanglements can also be realized in the system. These two types of tripartite entanglements can be easily transferred from one type to the other by adjusting the detuning or dissipation ratio. Moreover, the bipartite and tripartite entanglements and their transfer are all robust against temperature. Furthermore, by introducing supermodes formed by the photon and magnon modes, we find that the entanglement between the two mechanical modes can be obtained under the condition of an extremely low temperature. And the effective detuning region of the YIG phonon-membrane phonon entanglement is complementary to the detuning regions of other bipartite entanglements. Our results indicate that the combination of cavity magnomechanical and optomechanical systems could provide more flexible controllability of bipartite and tripartite entanglements and their transfer and could serve as a potential quantum interface among microwave, magnon, and mechanical systems.
We theoretically propose a cavity magnomechanical system with a levitated yttrium iron garnet sphere to study the entanglement characteristics between subsystems. The system consists of microwave photon, magnon, and mechanical phonon modes, where the photon and magnon modes can be driven by external microwave sources. We find that with the appropriate choice of the suspension position, the effective couplings between the cavity field and the magnon and phonon modes can be established, thus inducing the generation of bipartite entanglement and genuine tripartite entanglement in the system. Further, we also analyze in detail the influences of the radius of the sphere, the detunings of the cavity and magnon modes, the driving power, the frequency of the phonon mode, and the environment temperature on the characteristics of the quantum entanglement. The results obtained here indicate that the bipartite and tripartite entanglements can be manipulated by changing the radius and the oscillation frequency of the sphere in addition to changing the parameters of the cavity field, and therefore, the levitated magnomechanical system has a potential application in the study of macroscopic quantum phenomena.
Abstract We propose a scheme to generate steady-state bipartite and tripartite entanglement in the cavity magnomechanical system, which consists of a microwave (MW) cavity field, three magnons, and a phonon mode. The three magnons are coupled to the MW cavity via the magnetic dipole interaction, and one of them is also coupled to the phonon mode through the magnetostrictive force. By utilizing the nonlinearity of the magnetostrictive force and the cavity-magnon interaction, the three magnons become mutually entangled, and the steady-state of the system displays a genuine tripartite entanglement. We found that there are optimum parameters, including the detunings and the cavity-magnon coupling, which lead to maximum entanglement. Moreover, the entanglement is robust against thermal effects.
We show how to generate tripartite entanglement in a cavity magnomechanical system which consists of magnons, cavity microwave photons, and phonons. The magnons are embodied by a collective motion of a large number of spins in a macroscopic ferrimagnet, and are driven directly by an electromagnetic field. The cavity photons and magnons are coupled via magnetic dipole interaction, and the magnons and phonons are coupled via magnetostrictive (radiation pressurelike) interaction. We show optimal parameter regimes for achieving the tripartite entanglement where magnons, cavity photons, and phonons are entangled with each other, and we further prove that the steady state of the system is a genuinely tripartite entangled state. The entanglement is robust against temperature. Our results indicate that cavity magnomechanical systems could provide a promising platform for the study of macroscopic quantum phenomena.
Quantum entanglement in cavity magnomechanical system has a wide range of applications in modern quantum technologies. In this work, we propose a theoretical scheme to generate and enhance quantum entanglement through cross-Kerr nonlinearity and mechanical parametric amplification (MPA) in a magnomechanical system. Our system is made of a magnonic mode that is simultaneously driving the acoustic phononic and the center-of-mass motion (CMM) phonon in a yttrium iron garnet sphere. The acoustic mode and the center-of-mass mechanical (CMM) mode are weakly coupled via the phonon hopping rate Jm. Moreover, the magnonic and phononic modes interact through cross-Kerr interaction, while the phononic mode is additionally driven via a Mechanical Parametric Amplification (MPA). Without the mechanical coupling (Jm=0) and the MPA, the generation of entanglement among the subsystems requires a relatively strong effective cross-Kerr coupling. However, when phonon hopping and MPA are accounted, quantum entanglement can be generated even for weak values of the cross-Kerr coupling strength, revealing the key role of these interactions in the engineering of quantum correlations in our proposal. Furthermore, the related purity of the generated entangled states remains high for the same parameter's regime, revealing that the generated quantum entanglement is established without significantly increasing the mixing of the involved states in the system. Our work suggests how robust and stable quantum correlations can be engineered in magnomechanical structures based on nonlinear interactions. These results are useful for modern quantum applications including quantum information processing, quantum communication, and quantum computational tasks.
We investigate theoretically macroscopic quantum coherence and tripartite entanglement in a three-mode magnomechanical system with a yttrium iron garnet sphere, which is simultaneously driven by a magnetic pump and a microwave field pump to establish an effective magnomechanical coupling. We discuss mainly the dependence of quantum properties on the driving power, the cavity field detuning and decay, the magnomechanical coupling strength, the bias magnetic field, and the temperature of an environment. It is found that the quantum coherence of the system can be attained easily in a large range of parameters. In contrast, tripartite photon-magnon-phonon entanglement can only be realized in a relatively small range of optical and magnetic parameters. In particular, the quantum coherence of the mechanical mode can be larger than that of the photon and magnon modes, which means that the environmental incoherence of the mechanical mode in the cavity magnomechanical system can be suppressed significantly. These results may help manipulate simultaneously the macroscopic quantum coherence and the tripartite entanglement of massive objects in coupled magnomechanical system, which may have potential applications for realizing highly tunable information processing through the flexible control of quantum properties.