We propose a scheme to achieve nonreciprocal mechanical squeezing in a hybrid Kerr-modified cavity magnomechanical system, where the magnon mode is driven by two-tone microwave fields. The nonreciprocity originates from the magnon Kerr effect. Strong mechanical squeezing beyond the 3 dB limit can be nonreciprocally generated by adjusting the magnon frequency detuning, effective magnomechanical coupling strength, as well as the damping of the oscillator and the dissipation of the cavity. Importantly, the proposed scheme is robust against environmental thermal noise and system dissipation, ensuring its feasibility under current experimental conditions. This work may pave the way for the development of nonreciprocal quantum devices, such as isolators and circulators. Furthermore, the ability to achieve such robust mechanical squeezing has significant implications for advancing quantum precision measurements in metrology and sensing, offering new opportunities for exploring quantum-enhanced technologies.
We propose a scheme to achieve nonreciprocal mechanical squeezing in a hybrid Kerr-modified cavity magnomechanical system, where the magnon mode is driven by two-tone microwave fields. The nonreciprocity originates from the magnon Kerr effect. Strong mechanical squeezing beyond the 3 dB limit can be nonreciprocally generated by adjusting the magnon frequency detuning, effective magnomechanical coupling strength, as well as the damping of the oscillator and the dissipation of the cavity. Importantly, the proposed scheme is robust against environmental thermal noise and system dissipation, ensuring its feasibility under current experimental conditions. This work may pave the way for the development of nonreciprocal quantum devices, such as isolators and circulators. Furthermore, the ability to achieve such robust mechanical squeezing has significant implications for advancing quantum precision measurements in metrology and sensing, offering new opportunities for exploring quantum-enhanced technologies.
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.
Abstract In this study, a scheme is proposed to generate nonreciprocal strong mechanical squeezing in a cavity‐magnon optomechanical system based on the Kerr nonlinearity of the yttrium‐iron garnet (YIG) sphere. It is found that the magnon squeezing can be directly produced by the Kerr effect and it can induce strong mechanical squeezing through the squeezing transfer achieved by the cavity‐magnon interaction and the optomechanical interaction. The results further show that the mechanical mode coupled to the cavity can achieve squeezing effect in the selected magnetic field direction, but not in the opposite one. Moreover, by properly adjusting the magnon effective detuning and the Kerr effect strength, the degree of squeezing of the mechanical mode can even beyond the 3‐dB limit, and the optimal conditions for generating stronger squeezing are obtained. This work has important applications in the nonreciprocal quantum devices, quantum information processing, and quantum precision measurement.
We investigate quantum coherence in a hybrid cavity magnomechanical system incorporating a squeezed-magnon drive. By analyzing the Gaussian quantum coherence of the cavity, magnonic, and mechanical subsystems, as well as the total system coherence, we identify the critical roles of phase control, coupling strength, drive power, and thermal noise. We show that the squeezing amplitude and phase precisely modulate the effective magnon frequency and damping, enabling phase-dependent enhancement and nonreciprocal transfer of coherence. Our systematic parameter analysis indicates that increasing driving power and photon-magnon coupling enhances quantum coherence, while thermal decoherence leads to its degradation. However, this effect is partially suppressed by the presence of magnon squeezing. The results show that squeezed magnons are a robust and tunable resource for controlling, stabilizing, and optimizing quantum coherence in cavity magnomechanical platforms, offering potential applications in hybrid magnonic systems and coherent quantum information processing.
Abstract Microwave–optical entanglement is essential for efficient quantum communication, secure information transfer, and integrating microwave and optical quantum systems to advance hybrid quantum technologies. In this work, we demonstrate how the magnon Kerr effect can be harnessed to generate and control nonreciprocal entanglement in cavity optomagnomechanics (COMM). This effect induces magnon frequency shifts and introduces pair-magnon interactions, both of which are tunable through the magnetic field direction, enabling nonreciprocal behavior. By adjusting system parameters such as magnon frequency detuning, we show that magnon–phonon, microwave–optical photon–photon, and optical photon–magnon entanglement can be nonreciprocally enhanced and rendered more robust against thermal noise. Additionally, the nonreciprocity of entanglement can be selectively controlled, and ideal nonreciprocal entanglement is achievable. This work paves the way for designing nonreciprocal quantum devices across the microwave and optical regimes, leveraging the unique properties of the magnon Kerr effect in COMM.
We propose a scheme for realizing nonreciprocal transparency, Fano resonances, and slow/fast light in a hybrid cavity magnomechanical system containing two YIG spheres and a mechanical resonator. The nonreciprocal behavior originates from the magnon Kerr nonlinearity, which induces direction-dependent frequency shifts and modifies the interference pathways among cavity photons, magnons, and phonons. We show that the hybrid system supports multiple transparency windows arising from magnon- and magnomechanical-induced interference processes. The Kerr interaction strongly reshapes these transparency features, producing asymmetric Fano resonance line shapes and enabling controllable nonreciprocal transmission. Furthermore, the associated dispersion exhibits pronounced directional asymmetry, leading to giant differences in the group delay for opposite propagation directions and allowing reversible switching between slow- and fast-light regimes. We investigate the roles of hybrid coupling strengths and dissipation channels and identify parameter regimes where the nonreciprocal response is maximized. These findings establish Kerr-engineered magnomechanical systems as promising platforms for integrated nonreciprocal microwave photonics and quantum information technologies.
Abstract We propose a scheme to generate squeezed states in a cross-shaped cavity magnonics system by Kerr effect originating from the magnetocrystalline anisotropy. The system consists of two microwave cavities and a yttrium iron garnet sphere supporting a magnon mode embodying the collective spin motion, and each cavity mode is coupled with the magnon mode through the magnetic-dipole interaction. It is demonstrated that simultaneous squeezing of the two microwave cavity modes and the magnon mode can be achieved due to Kerr nonlinearity, and the squeezing of the magnon mode can break the 3 dB limit. By utilizing a Bogoliubov transformation, a new perspective on the underlying physical mechanism for the generation of the squeezing using Kerr nonlinearity is provided. Moreover, we also demonstrate the strong robustness of the magnon mode’s squeezing against the system dissipation and environmental temperature. The present scheme provides a promising platform for quantum information processing, holding significant implications for quantum metrology and precision measurement.