We present a theoretical investigation of quantum entanglement enhancement in an electro-optomechanical system comprising a ring cavity with two Coulomb-coupled mechanical resonators and an embedded optical parametric amplifier (OPA). The system dynamics are governed by radiation pressure interactions between the optical field and mechanical modes, modified by both the Coulomb coupling and OPA-induced squeezing. Through a comprehensive quantum Langevin analysis and linearization approach, we demonstrate how these competing interactions can be exploited to generate and control entanglement. Our key finding is that the Coulomb interaction strength is fundamental for generating bipartite entanglement, both between directly coupled mechanical modes and, more remarkably, between optical and mechanical modes, thereby influencing the entire system. The OPA parameters, namely the gain and phase, provide powerful control knobs for entanglement optimization. Notably, the OPA enhances entanglement robustness against thermal noise, resulting in stronger quantum correlations. We quantify these effects through covariance matrix methods and logarithmic negativity measures. The study provides new insights into hybrid optomechanical entanglement generation, showing how combined charge-mediated coupling and optical squeezing can overcome typical limitations of purely optomechanical systems. These results offer practical guidelines for experimental implementations in quantum information processing and macroscopic quantum state engineering, particularly in systems where environmental noise and parameter stability are critical concerns.
We present a theoretical investigation of quantum entanglement enhancement in an electro-optomechanical system comprising a ring cavity with two Coulomb-coupled mechanical resonators and an embedded optical parametric amplifier (OPA). The system dynamics are governed by radiation pressure interactions between the optical field and mechanical modes, modified by both the Coulomb coupling and OPA-induced squeezing. Through a comprehensive quantum Langevin analysis and linearization approach, we demonstrate how these competing interactions can be exploited to generate and control entanglement. Our key finding is that the Coulomb interaction strength is fundamental for generating bipartite entanglement, both between directly coupled mechanical modes and, more remarkably, between optical and mechanical modes, thereby influencing the entire system. The OPA parameters, namely the gain and phase, provide powerful control knobs for entanglement optimization. Notably, the OPA enhances entanglement robustness against thermal noise, resulting in stronger quantum correlations. We quantify these effects through covariance matrix methods and logarithmic negativity measures. The study provides new insights into hybrid optomechanical entanglement generation, showing how combined charge-mediated coupling and optical squeezing can overcome typical limitations of purely optomechanical systems. These results offer practical guidelines for experimental implementations in quantum information processing and macroscopic quantum state engineering, particularly in systems where environmental noise and parameter stability are critical concerns.
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.
This paper investigates the deterministic generation and coherent control of continuous-variable bipartite and tripartite entanglement within a multi-mirror electro-optomechanical ring cavity. The proposed architecture integrates radiation pressure with tunable Coulomb interactions, governed by external gate voltages, to establish quantum correlations between an intracavity optical field and a collective of four mechanical oscillators. We perform a rigorous stability analysis of the system, identifying the operational regimes across a broad range of free parameters, and evaluate the generation of tripartite entanglement within two distinct subsystems. Our numerical results demonstrate that while standard coherent driving combined with Coulomb coupling can generate entanglement, it is restricted to narrow detuning regions. In contrast, the introduction of squeezed light dramatically enhances quantum correlations, facilitating entanglement over a significantly wider range of normalized detuning without compromising the stability of the optomechanical system. A central finding is that the fixed charged body serves as a dynamic control parameter rather than a static component; by effectively tuning the mechanical susceptibility, it enables the generation of optomechanical entanglement that is both stronger and more resilient to thermal noise than the mechanical–mechanical entanglement mediated by direct Coulomb interaction. Furthermore, the external gate voltage provides a reliable mechanism for the continuous tuning of mechanical coupling strengths. From a practical perspective, the ability of the Coulomb coupling to act as a quantum switch for activating or suppressing entanglement suggests significant potential for quantum information control and state transfer within hybrid quantum architecture networks.
In this paper, we investigated the quantum correlation of nano-electro-optomechanical system enhanced by an optical parametric amplifier (OPA) and Coulomb-type interaction. In particular, we consider a hybrid system consisting of a cavity and two charged mechanical oscillators with an OPA, where the optical cavity mode is coupled with a charged mechanical oscillator via radiation pressure, and the two charged mechanical oscillators are coupled through a Coulomb interaction. We use logarithmic negativity to quantify quantum entanglement, and quantum discord to measure the quantumness correlation between the two mechanical oscillators. We characterize quantum steering using the steerability between the two mechanical oscillators. Our results show that the presence of OPA and strong Coulomb coupling enhances the quantum correlations between the two mechanical oscillators. In addition, Coulomb interactions are more prominent in quantum correlations. Besides, in the presence of OPA, the maximum amount of quantum entanglement, quantum steering, and quantum discord were achieved between the two mechanical oscillators is greater than in the absence of OPA. Moreover, a proper phase choice of the optical field driving the OPA enhances quantum correlations under suitable conditions. We obtain quantum entanglement confines quantum steering and quantum discord beyond entanglement. Furthermore, quantum entanglement, quantum steering, and quantum discord decrease rapidly with increasing temperature as a result of decoherence. In addition, quantum discord persists at higher temperature values, although the quantum entanglement between the systems also vanishes completely. Our proposed scheme enhances quantum correlation and proves robust against fluctuations in the bath environment. We believe that the present scheme of quantum correlation provides a promising platform for the realization of continuous variable quantum information processing.
In this paper, we investigate the degree of steady-state entanglement using a hybrid optomechanical system, where the separate cavities contain a degenerate optical parametric amplifier (DOPA). Particularly, under the linearization approximation, the steady-state entanglement is quantified through logarithmic negativity. The bipartite entanglement between cavity-mechanical oscillator modes and two cavity modes is analyzed through the applicable choice of nonlinear gain of OPA, optical cavity detuning, and cavity-cavity coupling strength. It is found that the steady-state entanglement increases with the nonlinear gain of OPA medium and normalized detuning. We further emphasize the influence of cavity-cavity coupling parameter on the bipartite entanglement, and the generation of entanglement can be transferred entirely due to the coupling strengths. The main contribution of coupling parameters on the entanglement of the two modes of mechanical oscillators significantly altered and increased. The observed possibility of transferring the emerging entanglement of the states of light in the two cavities to the modes of the accompanying mechanical oscillators is expected to be a valuable asset in the practical realization of quantum information processing .
Quantum optomechanical systems enable versatile control of non-classical light. We study two-mode squeezed-light generation in a driven optomechanical cavity with parametrically amplified optical modes coupled to mechanical resonator. Coherent driving reveals a rich control landscape where parametric nonlinearity, optomechanical coupling, and reservoir interactions jointly tailor quantum correlations-including two-mode squeezing, entanglement, steering, and discord. Remarkably, mechanical oscillators not only mediate optical entanglement but also act as a squeezing resource, enabling enhancement or suppression of quantum correlations via parameter tuning. We derive steady-state second-order moments and closed-form covariance matrix expressions, quantifying entanglement via logarithmic negativity, steering via Reid criterion, and discord via von Neumann entropy, providing a comprehensive framework for optimized generation of quantum correlations in hybrid quantum systems.
We report an efficient mechanism to generate mechanical entanglement in a two-cascaded cavity optomechanical system with optical parametric amplifiers (OPAs) inside the two coupled cavities. We use the especially tuned OPAs to squeeze the hybrid mode composed of two mechanical modes, leading to strong macroscopic entanglement between the two movable mirrors. The squeezing parameter as well as the effective mechanical damping are both modulated by the OPA gains. The optimal degree of mechanical entanglement therefore depends on the balanced process between coherent hybrid mode squeezing and dissipation engineering. The mechanical entanglement is robust to strong cavity decay, going beyond simply resolved sideband regime, and is resistant to reasonable high thermal noise. The scheme provides an alternative way for generating strong macroscopic entanglement in cascaded optomechanical systems.