We propose a mechanism to simultaneously enhance quantum cooling and entanglement via coupling an auxiliary microwave cavity to a magnomechanical cavity. The auxiliary cavity acts as a dissipative cold reservoir that can efficiently cool multiple localized modes in the primary system via beam-splitter interactions, which enables us to obtain strong quantum cooling and entanglement. We analyze the stability of the system and determine the optimal parameter regime for cooling and entanglement under the auxiliary-microwave-cavity-assisted (AMCA) scheme. The maximum cooling enhancement rate of the magnon mode can reach 98.53%, which clearly reveals that the magnomechanical cooling is significantly improved in the presence of the AMCA. More importantly, the dual-mode entanglement of the system can also be significantly enhanced by AMCA in the full parameter region, where the initial magnon-phonon entanglement can be maximally enhanced by a factor of about 11. Another important result of the AMCA is that it also increases the robustness of the entanglement against temperature. Our approach provides a promising platform for the experimental realization of entanglement and quantum information processing based on cavity magnomechanics.
We propose a mechanism to simultaneously enhance quantum cooling and entanglement via coupling an auxiliary microwave cavity to a magnomechanical cavity. The auxiliary cavity acts as a dissipative cold reservoir that can efficiently cool multiple localized modes in the primary system via beam-splitter interactions, which enables us to obtain strong quantum cooling and entanglement. We analyze the stability of the system and determine the optimal parameter regime for cooling and entanglement under the auxiliary-microwave-cavity-assisted (AMCA) scheme. The maximum cooling enhancement rate of the magnon mode can reach 98.53%, which clearly reveals that the magnomechanical cooling is significantly improved in the presence of the AMCA. More importantly, the dual-mode entanglement of the system can also be significantly enhanced by AMCA in the full parameter region, where the initial magnon-phonon entanglement can be maximally enhanced by a factor of about 11. Another important result of the AMCA is that it also increases the robustness of the entanglement against temperature. Our approach provides a promising platform for the experimental realization of entanglement and quantum information processing based on cavity magnomechanics.
We propose a mechanism to significantly enhance the photon-phonon entanglement twice by coupling an auxiliary magnetic sphere to a standard cavity magnomechanical system. The deformed sphere acts as a cold reservoir that can simultaneously cool two hybrid modes superposed over the optical cavity and the mechanical oscillator by modulating the relationship between the coupling strengths, which enables us to obtain large steady-state cavity-oscillator entanglement. On the basis of the double-mode cooling effect, the steady-state photon-phonon entanglement can be significantly improved by opening the single-coupled auxiliary-sphere-assisted channel due to the fact that the nonsuperposed optical mode can be efficiently cooled via the auxiliary sphere. More importantly, the photon-phonon entanglement can be significantly enhanced again by switching the dual-coupled auxiliary-sphere-assisted (DC-ASA) passage, where the auxiliary sphere serves as an additional cold bath to simultaneously cool both the nonsuperposed optical mode and the reservoir mode. Moreover, in the DC-ASA regime, the steady-state entanglement is more robust against the mechanical thermal noise. This DC-ASA scheme can be potentially applied to accelerate magnomechanical cooling and enhance magnomechanical squeezing.
Abstract We study photon–phonon entanglement in a cavity magnomechanical system assisted by an optical parametric amplifier (OPA) and an auxiliary magnon mode. In this hybrid system, the OPA modifies the cavity-field fluctuations through its gain and phase, while the auxiliary magnon mode introduces an additional coherent pathway for strengthening the cavity-phonon quantum correlation. By employing the linearized quantum Langevin equations and the covariance-matrix formalism, we investigate the bipartite entanglement of the system. We find that the auxiliary magnon mode enhances the cavity-phonon entanglement in a suitable parameter regime, and that the OPA can further improve the entanglement through properly chosen gain and phase. In addition, their combined action broadens the parameter region for strong entanglement and improves its robustness against thermal noise. Our scheme provides a promising approach for achieving enhanced and robust entanglement in cavity magnomechanical systems.
Abstract A hybrid cavity magnomechanical system to transfer the bipartite entanglements and achieve the strong microwave photon–phonon entanglement based on the reservoir engineering approach is constructed. The magnon mode is coupled to the microwave cavity mode via magnetic dipole interaction and to the phonon mode via magnetostrictive force (optomechanical‐like). It is shown that the initial magnon‐phonon entanglement can be transferred to the photon‐phonon subspace in the case of these two interactions cooperating. In the reservoir‐engineering parameter regime, the initial entanglement is directionally transferred to the photon‐phonon subsystem, so a strong bipartite entanglement in which the magnon mode acts as the cold reservoir to effectively cool the Bogoliubov mode delocalized over the cavity and the mechanical deformation mode is obtained. Moreover, dual‐mode cooling is realized by engineering the dissipation of photon and phonon modes within the target mode, which allows entanglement to be further enhanced. The results indicate that the steady‐state entanglement is robust against temperature. The dual‐mode cooling reservoir engineering scheme can potentially be extended to other three‐mode quantum systems.
We construct a hybrid cavity magnomechanical system to transfer the bipartite entanglements and achieve the strong microwave photon-phonon entanglement based on the reservoir engineering approach. The magnon mode is coupled to the microwave cavity mode via magnetic dipole interaction, and to the phonon mode via magnetostrictive force (optomechanical-like). It is shown that the initial magnon-phonon entanglement can be transferred to the photon-phonon subspace in the case of these two interactions cooperating. In reservoir-engineering parameter regime, the initial entanglement is directionally transferred to the photon-phonon subsystem, so we obtain a strong bipartite entanglement in which the magnon mode acts as the cold reservoir to effectively cooling the Bogoliubov mode delocalized over the cavity and the mechanical deformation mode. Moreover, as the dissipation ratio between the cold reservoir mode and the target mode increases, we can achieve greater quantum entanglement and better cooling effect. Our results indicate that the steady-state entanglement is robust against temperature. The scheme may provides potential applications for quantum information processing, and is expected to be extended to other three-mode systems.
We demonstrate a scheme to realize high-efficiency entanglement of two microwave fields in a dual opto-magnomechanical system. The magnon mode simultaneously couples with the microwave cavity mode and phonon mode via magnetic dipole interaction and magnetostrictive interaction, respectively. Meanwhile, the phonon mode couples with the optical cavity mode via radiation pressure. Each magnon mode and optical cavity mode adopts a strong red detuning driving field to activate the beam splitter interaction. Therefore, the entangled state generated by the injected two-mode squeezed light in optical cavities can be eventually transferred into two microwave cavities. A stationary entanglement E a 1 a 2 =0.54 is obtained when the input two-mode squeezed optical field has a squeezing parameter r = 1. The entanglement E a 1 a 2 increases as the squeezing parameter r increases, and it shows the flexible tunability of the system. Meanwhile, the entanglement survives up to an environmental temperature about 385 mK, which shows high robustness of the scheme. The proposed scheme provides a new mechanism to generate entangled microwave fields via magnons, which enables the degree of the prepared microwave entanglement to a more massive scale. Our result is useful for applications which require high entanglement of microwave fields like quantum radar, quantum navigation, quantum teleportation, quantum wireless fidelity (Wi-Fi) network, etc.
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.