We propose a novel scheme to generate and manipulate bipartite and tripartite entanglement and Bell nonlocality in a closed-loop three-mode optomechanical system, where two optical modes are simultaneously coupled to a mechanical mode via typical optomechanical interactions and also coupled to each other through field transmission. This configuration gives rise to a phase-sensitive coupling, in which the relative phase directly controls the population distribution between two optical modes, enabling coherent redistribution of quantum correlations. By tuning this relative phase, we achieve deterministic switching of bipartite entanglement between two optical-mechanical pairs, as well as tunable genuine tripartite entanglement among three modes. Employing the displaced-parity measurement, we construct both the bipartite and tripartite Bell inequalities in phase space and observe maximal violations of approximately
2.32 and
3, respectively, which coincide exactly with the values achievable for ideal bipartite and tripartite Einstein-Podolsky-Rosen states. Counterintuitively, we find that the tripartite Bell nonlocality can persist even when the genuine tripartite entanglement is absent, providing deeper insight into the relationship between these two types of quantum correlations. Furthermore, we systematically analyze the effects of mechanical dissipation and thermal noise, identifying the parameter regions where Bell violation survives under realistic experimental conditions. Our results establish a comprehensive framework for generating, controlling, and verifying multipartite quantum correlations, paving the way towards phase-tunable quantum networks and noise-resilient tests of quantum foundations.
Optoelectromechanical quantum interfaces can be utilized to connect systems with distinctively different frequencies in hybrid quantum networks. Here we present a scheme of nonreciprocal quantum-state conversion between microwave and optical photons via an optoelectromechanical interface. By introducing an auxiliary cavity and manipulating the phase differences between the linearized light-matter couplings, unidirectional state transmission that is immune to mechanical noise can be achieved. This interface can function as an isolator, a circulator, and a two-way switch that routes the input state to a designated output channel. We show that under a generalized impedance matching condition the state conversion can prevent thermal fluctuations of the mechanical mode from propagating to the cavity outputs and reach high fidelity. The realization of this scheme is also discussed.
We propose a scheme to generate one-way steering, bipartite, and genuine tripartite entanglement in a five-mode hybrid cavity electro-optomechanical system consisted of an optical cavity, a mechanical resonator, and three microwave cavity modes with the help of a squeezed vacuum field. The optical cavity is pumped by a squeezed vacuum field. The mechanical resonator is formed by a freely vibrating silicon nitride membrane, which is a part of a capacitor in an inductor–capacitor circuit forming three microwave resonators. We find that there is robust entanglement and one-way steering between the optical cavity mode and microwave cavity modes in the presence of the squeezed vacuum field. Particularly, there is steady-state genuine tripartite entanglement between three microwave cavity modes, which is robust against thermal fluctuations. Our scheme could be useful for various quantum tasks based on hybrid electro-optomechanical systems fabricated on chips.
We present a scheme for realizing phase-controlled entanglement in a microwave optomechanical system comprising two microwave cavities and two mechanical oscillators. Under specific driving conditions, we show that this optomechanical interface can be exploited to generate simultaneously the stationary cavity–cavity entanglement, mechanical–mechanical entanglement, and cavity–mechanical entanglement. Due to the closed loop interaction, we find that the entanglement can be controlled flexibly by tuning the phase difference between the optomechanical coupling strengths. The dependence of the entanglement on the amplitudes of the optomechanical coupling strengths is also explored in detail. Moreover, the bipartite entanglements are robust against temperature, and it is shown that the mechanical oscillators are cooled to the ground state in the parameter regimes for observing entanglement.
Abstract We propose an effective scheme to generate the squeezed vacuum states of two microwave fields, bipartite and genuine tripartite entanglement in a compound four-mode electro-optomechanical system with two driving lasers of different amplitudes. We find that two microwave fields can be squeezed simultaneously when the effective coupling constants between mechanical oscillator and two microwave fields are chosen appropriately. In particular, the squeezing of one microwave mode can be larger than 3 dB even at high temperature. We also find that bipartite and genuine tripartite entanglement can be generated in this system which are robust against thermal fluctuations. Our scheme may have potential applications in quantum information processing and quantum metrology.
Cavity optomagnomechanics provides a versatile platform to explore macroscopic quantum correlations, particularly nonreciprocal entanglement. In this work, we propose a theoretical scheme to generate switchable bipartite and tripartite entanglement in an optomagnomechanical ring cavity by exploiting phase-controlled magnon squeezing. Indeed, two spatially separated ferrimagnetic YIG microbridges become entangled through their magnetostriction-mediated coupling to mechanical motion and a common cavity field via radiation-pressure interaction. The squeezing process introduces two phase-dependent contributions to the magnon response, namely an effective detuning shift
Δθj and a quadrature-damping contribution
κθj, both of which reverse sign upon a
π phase shift, providing an in situ control to switch the entanglement response. The nonreciprocal entanglement is defined operationally through the asymmetric entanglement response under the phase reversal
θj→θj+π, quantified by normalized contrast ratios
CE and
CR, which measure the relative difference between the entanglement obtained at
θj and at the phase-reversed configuration
θj+π. The resulting phase-tuning method provides a flexible and robust route to achieve high-contrast bipartite and tripartite entanglement within stable parameter regions, establishing magnon squeezing as a practical quantum resource for switchable quantum correlations in hybrid platforms.