We propose a new mechanism to achieve nonreciprocal quantum entanglement in a cavity magnomechanical system by exploiting the chiral cavity-magnon coupling. The system consists of a magnon mode, a mechanical vibration mode, and two degenerate counter-propagating microwave cavity modes in a torus-shaped cavity. We show that nonreciprocal stationary microwave-magnon and -phonon bipartite entanglements and photon-magnon-phonon tripartite entanglement can be achieved by respectively driving different circulating cavity modes that hold a chiral coupling to the magnon mode. The nonreciprocal entanglements are shown to be robust against various experimental imperfections. We specifically show how such nonreciprocal entanglement can realize the channel multiplexing quantum teleportation from a microwave field to a solid-state magnon mode. The work may find promising applications of the cavity magnomechanical systems in noise-tolerant quantum processing, channel multiplexing quantum teleportation, and chiral magnonic quantum networks.
We propose a new mechanism to achieve nonreciprocal quantum entanglement in a cavity magnomechanical system by exploiting the chiral cavity-magnon coupling. The system consists of a magnon mode, a mechanical vibration mode, and two degenerate counter-propagating microwave cavity modes in a torus-shaped cavity. We show that nonreciprocal stationary microwave-magnon and -phonon bipartite entanglements and photon-magnon-phonon tripartite entanglement can be achieved by respectively driving different circulating cavity modes that hold a chiral coupling to the magnon mode. The nonreciprocal entanglements are shown to be robust against various experimental imperfections. We specifically show how such nonreciprocal entanglement can realize the channel multiplexing quantum teleportation from a microwave field to a solid-state magnon mode. The work may find promising applications of the cavity magnomechanical systems in noise-tolerant quantum processing, channel multiplexing quantum teleportation, and chiral magnonic quantum networks.
Quantum entanglement, a key element for quantum information is generated with a cavity-magnomechanical system. It comprises of two microwave cavities, a magnon mode and a vibrational mode, and the last two elements come from a YIG sphere trapped in the second cavity. The two microwave cavities are connected by a superconducting transmission line, resulting in a linear coupling between them. The magnon mode is driven by a strong microwave field and coupled to cavity photons via magnetic dipole interaction, and at the same time interacts with phonons via magnetostrictive interaction. By breaking symmetry of the configuration, we realize nonreciprocal photon transmission and one-way bipartite quantum entanglement. By using current experimental parameters for numerical simulation, it is hoped that our results may reveal a new strategy to built quantum resources for the realization of noise-tolerant quantum processors, chiral networks, and so on.
Quantum entanglement is a key element for quantum information that can be generated in a double-cavity magnomechanical system that consists of two microwave cavities, a magnon mode, and a vibrational mode. The magnon mode, which describes a collective excitation of spins, is excited by a strong microwave field. In this system, cavity photons and magnons are coupled via magnetic dipole interaction. The magnons and phonons interact via magnetostrictive interaction, while the two microwave cavities can be connected by a superconducting transmission line. By changing the external driving fields on the two cavities to break the symmetry of spatial inversion, we propose a scheme for asymmetric transmission and entanglement. With the use of current experimental parameters for numerical simulation, we believe our results may reveal a new strategy to build quantum resources for noise-tolerant quantum processors and realize chiral networks.
Cavity magnomechanics has opened a new frontier in quantum electrodynamics, yielding several significant theoretical and experimental results. In this paper, we propose a different theoretical mechanism to achieve nonreciprocal macroscopic entanglement among magnons, photons, and phonons based on magnon squeezing. Specifically, reversing the squeezing phase, namely, θ → θ + π , reverses the frequency shift and the effective dissipation rate simultaneously, producing two experimentally distinct configurations that enable nonreciprocal entanglement. Indeed, in contrast to conventional approaches that control only frequency shifts, we show how precise control of the amplitude and phase of the squeezed mode allows us to obtain a tunable nonreciprocity of entanglement. The magnons resulting from the collective motion of the spin in a macroscopic ferrimagnet become coupled to the microwave photons via magnetic dipole interaction and to the phonons via magnetostrictive interaction. Moreover, we show that the proposed scheme achieves ideal nonreciprocity, which can be optimized by cavity-magnon coupling and bath temperature control. Finally, by using the parameters that are experimentally feasible with current technologies, this work provides promising perspectives for hybrid magnon-based quantum technologies.
We propose a scheme to create nonreciprocal entanglement in a spinning cavity magnomechanical system. The setup comprises a whispering gallery mode resonator with two counterpropagating modes, simultaneously coupled to yttrium iron garnet. By spinning the resonator, the counterpropagating modes undergo an opposite Fizeau drag caused by the optical Sagnac effect. We show that in a spinning resonator, the cavity-magnon-phonon modes get entangled along a chosen direction while remaining fully uncorrelated in the other. The degree of nonreciprocity is determined by the drive detuning and the spinning velocity of the resonator. Our work provides a different route to achieve chiral control of quantum entanglement involving magnon-photon-phonon modes.
Cavity magnomechanics has shown great potential in studying macroscopic quantum effects, especially for quantum entanglement, which is a key resource for quantum information science. Here we propose to realize magnon mediated nonreciprocal photon-phonon entanglement, which exhibits asymmetry when opposite magnetic or driving fields are respectively applied to the magnons with the Kerr effect or the photons with the Sagnac effect. We find that the mean magnon number can selectively exhibit nonreciprocal linear or nonlinear (bistable) behavior with the strength of the strong driving field on the cavity. Assisted by this driving field, the magnon-phonon coupling is greatly enhanced, leading to the nonreciprocal photon-phonon entanglement via the swapping interaction between the magnons and photons. This nonreciprocal entanglement can be significantly enhanced with the magnon Kerr and Sagnac effects. Given the available parameters, the nonreciprocal photon-phonon entanglement can be preserved at $\ensuremath{\approx}3$ K, showing remarkable resilience against the bath temperature. The result reveals that our paper holds promise in developing various nonreciprocal devices with both the magnon Kerr and Sagnac effects in cavity magnomechanics.
We theoretically propose a scheme for achieving nonreciprocal bipartite and tripartite entanglement among magnons, photons, and phonons utilizing the Barnett effect in a cavity magnomechanical (CMM) system where a rotating yttrium iron garnet sphere is placed in a microwave cavity. The Barnett effect induces a Barnett frequency shift that can be effectively controlled to be either positive or negative by adjusting the direction of the magnetic field. As a result, nonreciprocal bipartite and tripartite entanglement can be achieved, exhibiting robustness against the bath temperature. Our work provides a very accessible way to manipulate photon-magnon-phonon quantum resources based on CMM devices with the Barnett effect.