We propose a method to enhance bipartite and tripartite entanglement in cavity magnomechanics using an optical parametric amplifier (OPA). We analyze this system and identified parametric regimes where different types of entanglement are enhanced. We show that a proper choice of phase of the parametric amplifier leads to the enhancement of the bipartite entanglements. Moreover, the tripartite entanglement is also significantly enhanced in the presence of the OPA. The OPA not only enhances the strength of entanglement but also increases the domain of entanglement over a wider space of detunings as compared to the system when no OPA is present. Similarly, the robustness of entanglement against temperature is also enhanced. Another important consequence of the OPA is the fact that it relaxes the requirement of strong magnon-phonon coupling to generate cavity-magnon entanglement which is necessary for the case when the OPA is not present. We believe that the presented scheme is a step forward to realize robust quantum entanglement using current technology.
We propose a method to enhance bipartite and tripartite entanglement in cavity magnomechanics using an optical parametric amplifier (OPA). We analyze this system and identified parametric regimes where different types of entanglement are enhanced. We show that a proper choice of phase of the parametric amplifier leads to the enhancement of the bipartite entanglements. Moreover, the tripartite entanglement is also significantly enhanced in the presence of the OPA. The OPA not only enhances the strength of entanglement but also increases the domain of entanglement over a wider space of detunings as compared to the system when no OPA is present. Similarly, the robustness of entanglement against temperature is also enhanced. Another important consequence of the OPA is the fact that it relaxes the requirement of strong magnon-phonon coupling to generate cavity-magnon entanglement which is necessary for the case when the OPA is not present. We believe that the presented scheme is a step forward to realize robust quantum entanglement using current technology.
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.
We propose a scheme to generate bipartite and tripartite entanglements of three magnon modes in a three-cavity system using a nonlinear optical parametric amplifier (OPA). The three magnon modes in three YIG spheres are respectively placed inside three cavities near the maximum magnetic fields of the cavities and coupled to cavity modes via linear magnetic dipole interaction. Additionally, linear coupling interaction exists between two cavities. Using experimentally feasible parameters, we demonstrate that OPA can prepare these three magnon modes in a steady-state entangled state, bipartite and tripartite entanglements generally increase with the nonlinear interaction strength of OPA. An alternative approach to enhance quantum entanglement involves multiplexed OPA inputs. By employing individual OPA for each cavity, we observe a significant improvement in entanglement generation. All the entanglements are robust against bath temperature.
Tripartite entanglement as a remarkable resource in quantum information science has been extensively investigated in hybrid quantum systems, whereas it is generally weak and prone to be suppressed by noise, restricting its practical application in quantum technologies. Here, we propose how to enhance the tripartite entanglement among magnons, photons, and phonons in a hybrid cavity-magnon optomechanical system by exploiting a synergistic effect of the optical parametric amplification (OPA) and mechanical parametric amplification (MPA). We find that in the case of individually applying the OPA or MPA, the tripartite entanglement can be enhanced by several folds. Remarkably, upon suitably tuning the phase matching of the two parametric fields presented simultaneously, the strengths of the entanglement can be further enhanced due to the constructive interference between the OPA and MPA. We also show that our method can improve the robustness of the entanglement against thermal noise. Our work provides a promising method for manipulating the entanglement with easy tunability and may serve as a useful tool for the enhancement and protection of fragile quantum resources.
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.
This study investigates the generation and enhancement of quantum entanglement in an electro-optomechanical ring cavity system. The setup integrates two Coulomb-coupled mechanical resonators, which serve as the fundamental mechanism for the generation of bipartite and tripartite entanglement via charge mediated coupling. We then demonstrate the significant enhancement of this entanglement via a nonlinear parametric drive (an optical parametric amplifier, OPA), which injects a controllable nonlinearity into the cavity. We derive the system's Hamiltonian and the corresponding quantum Langevin equations, which are linearized around steady-state solutions to analyze Gaussian quantum fluctuations. Employing the covariance matrix formalism, we quantify bipartite entanglement via logarithmic negativity and tripartite entanglement via the minimum residual contangle. Our results unequivocally show that while the Coulomb interaction is indispensable for creating entanglement, the OPA acts as a powerful control tool, dramatically amplifying the degree of quantum correlations for all subsystems. We find that the strength of entanglement is highly sensitive to several parameters and can be optimized through the strategic selection of the OPA's gain and phase, the laser detuning, and the input power. A key finding is the existence of a trade-off, where parameters that maximize entanglement also constrain the stable operating regime of the system. Furthermore, thermal noise is shown to progressively degrade all quantum correlations, underscoring the necessity for low-temperature operation. These findings provide comprehensive guidance for parameter optimization, outlining a clear path from generation to enhancement, and highlight the potential of such hybrid systems as versatile platforms for controlling multipartite entanglement in quantum technologies.
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.