The generation of quantum correlations in hybrid quantum systems remains a central challenge due to the intrinsic limitations of linear interactions. In cavity magnomechanical platforms, the cavity-magnon coupling gives rise to hybridized cavity-magnon polaritons (CMPs). However, as a beam-splitter-type interaction, it does not by itself generate entanglement between the polariton modes in the absence of additional nonlinear or parametric processes. Here, we propose a mechanism based on multimode phonon mediation, in which multiple vibrational modes act as parallel scattering channels that couple the polaritons through Stokes and anti-Stokes processes. We show that , in the parameter regime explored here, the presence of multiple phonon modes leads to a monotonic enhancement of steady-state entanglement, thereby going beyond the limitations of conventional single-mode schemes. Furthermore, we demonstrate that quantum synchronization between the polariton modes originates from the same underlying scattering processes responsible for entanglement generation, yet exhibits an opposite scaling behavior with increasing phonon number for the phase quadrature, while the amplitude synchronization reveals collective squeezing that grows with the number of phonon channels. Our results provide new insights into the role of multimode interactions in shaping quantum correlations and establish a viable pathway for controlling entanglement and collective dynamics in hybrid magnomechanical platforms.
The generation of quantum correlations in hybrid quantum systems remains a central challenge due to the intrinsic limitations of linear interactions. In cavity magnomechanical platforms, the cavity-magnon coupling gives rise to hybridized cavity-magnon polaritons (CMPs). However, as a beam-splitter-type interaction, it does not by itself generate entanglement between the polariton modes in the absence of additional nonlinear or parametric processes. Here, we propose a mechanism based on multimode phonon mediation, in which multiple vibrational modes act as parallel scattering channels that couple the polaritons through Stokes and anti-Stokes processes. We show that , in the parameter regime explored here, the presence of multiple phonon modes leads to a monotonic enhancement of steady-state entanglement, thereby going beyond the limitations of conventional single-mode schemes. Furthermore, we demonstrate that quantum synchronization between the polariton modes originates from the same underlying scattering processes responsible for entanglement generation, yet exhibits an opposite scaling behavior with increasing phonon number for the phase quadrature, while the amplitude synchronization reveals collective squeezing that grows with the number of phonon channels. Our results provide new insights into the role of multimode interactions in shaping quantum correlations and establish a viable pathway for controlling entanglement and collective dynamics in hybrid magnomechanical platforms.
Abstract We present a scheme to entangle the vibrational phonon modes of two massive ferromagnetic spheres in a dual-cavity magnomechanical system. In each cavity, a microwave cavity mode couples to a magnon mode (spin wave) via the magnetic dipole interaction, and the latter further couples to a deformation phonon mode of the ferromagnetic sphere via a nonlinear magnetostrictive interaction. We show that by directly driving the magnon mode with a red-detuned microwave field to activate the magnomechanical anti-Stokes process a cavity–magnon–phonon state-swap interaction can be realized. Therefore, if the two cavities are further driven by a two-mode squeezed vacuum field, the quantum correlation of the driving fields is successively transferred to the two magnon modes and subsequently to the two phonon modes, i.e., the two ferromagnetic spheres become remotely entangled. Our work demonstrates that cavity magnomechanical systems allow to prepare quantum entangled states at a more massive scale than currently possible with other schemes.
The present study is based on a theoretically feasible scheme for the enhancement of entanglement between different bipartitions due to magnon squeezing in a two-cavity magnomechanical system, having two microwave cavity mode photons, a magnon mode, and phonon mode. The nonlinearity in the system is well enhanced owing to magnon squeezing, which is responsible for the enhancement of different bipartitions’ entanglement. By employing the standard Langevin approach, we found that the magnon squeezing parameter not only enhances the entanglement between directly coupled modes, but also has a considerable impact on indirectly coupled modes’ entanglement. In addition, we find the negative impact of the thermal bath for the mechanical mode on the generation of photon–phonon and magnon–phonon entanglements. Furthermore, magnon squeezing has shown a significant role in the entanglement robustness against thermal effects. Moreover, the tripartite entanglement among photon, magnon, and phonon is also considerably enhanced in the presence of magnon squeezing. This two-cavity magnomechanical system might be used in quantum tasks that require the enhancement of entanglement of indirectly coupled modes.
Generating long-distance quantum entanglement is crucial for advancing quantum information processing. In this work, we propose a protocol for generating remote magnon-phonon entanglement in a hybrid waveguide-magnomechanical system, where multiple spatially separated magnon modes couple to a common waveguide while interacting with their respective phonon modes. By applying tailored pulsed drives and engineering the magnomechanical interactions, our scheme enables the creation of diverse long-distance and dynamically stable entanglement. Beyond basic magnon-phonon two-mode entanglement, it supports genuine multimode entanglement between a single phonon and multiple magnons, bipartite entanglement between a single magnon and multiple phonons, as well as genuine four-mode entanglement involving two magnons and two phonons. Moreover, we show that dissipative magnon-magnon interactions mediated by traveling photons can generate substantially stronger remote entanglement than coherent couplings. Our work provides an experimentally feasible scheme for the remote generation of magnon-phonon entanglement.
Abstract We show how to entangle two cavity-magnon polaritons (CMPs) formed by two strongly coupled microwave cavity and magnon modes. This is realized by introducing vibration phonons, via magnetostriction, into the system that are dispersively coupled to the magnon mode. Stationary entanglement between two CMPs can be achieved when they are respectively resonant with the two sidebands of the drive field scattered by the phonons, and when the proportions of the cavity and magnon modes in the two polaritons are appropriately chosen. The entangled CMPs are macroscopic quantum states as the magnon mode contains a large number of spins, and can lead to the emission of frequency-entangled microwave photons, which find broad applications in microwave quantum information processing and quantum metrology.
The present work offers a comprehensive theoretical analysis of hybrid magnon-phononphoton systems operating in the nanocavity magnomechanical regime, where magnetostrictive coupling, microwave cavity fields, and mechanical vibrations interact coherently within a single engineered platform. The promising potential of these systems for quantum transduction, phonon-state engineering, and hybrid quantum networks motivates the development of a unified open-quantum-system framework grounded in Heisenberg-Langevin equations and input-output theory, which is applied across a hierarchy of increasingly complex physical regimes. The analysis begins with the derivation of magnon-photon and magnon-phonon coupling strengths for a thin-film device geometry using the Euler-Bernoulli principle, thereby establishing experimentally accessible parameter targets. Under red-detuned microwave driving, beam-splitter-type magnomechanical interactions enable sideband cooling of the mechanical mode and facilitate coherent quantum-state transfer between magnon and phonon subsystems, with quantitative predictions provided for cooperativity and cooling performance. Beyond the linear regime, the intrinsic Kerr nonlinearity of the magnon mode is incorporated, revealing a power-dependent renormalization of the effective magnon detuning. This results in phonon frequency shifts and a pronounced transient enhancement of the phonon damping rate at intermediate drive powers, effects that may be exploited to maximize cooling performance without increasing cavity photon occupation. Finally, a covariance-matrix formalism is developed for evaluating continuous-variable entanglement between the magnon and phonon modes, quantified by the logarithmic negativity. Sideband-selective driving generates robust stationary entanglement that persists against thermal noise across experimentally realized systems. Collectively, these findings establish nanocavity magnomechanics as a versatile platform for coherent quantum control, nonlinear sensing, and the generation of quantum correlations in solid-state hybrid systems.
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.