Abstract Quantum technologies critically rely on maintaining coherence and controllable correlations in open systems, yet these resources are fragile under dissipation and noise. To address this challenge, we investigate a hybrid platform composed of two identical three-level atoms in a V-type configuration coupled to a single-mode cavity field prepared in a squeezed coherent state. Using the Lindblad master equation, we numerically simulate the system dynamics, allowing a rigorous treatment of coherent atom–field interactions, interatomic couplings, and cavity losses. Our analysis reveals that squeezing introduces nonclassical correlations that enhance field coherence and support the generation of entanglement under specific regimes. Strong interatomic coupling stabilizes entanglement, while squeezing mitigates decoherence-induced losses. Conversely, large photon amplitudes and cavity dissipation degrade both coherence and bipartite correlations. Quantum steering emerges as the most fragile correlation, yet its persistence can be moderately extended through squeezing. These results identify squeezing and interatomic interactions as complementary resources for optimizing coherence, entanglement, and steering, offering practical strategies for robust quantum communication, information processing, and engineered nonclassical states.
Abstract Quantum technologies critically rely on maintaining coherence and controllable correlations in open systems, yet these resources are fragile under dissipation and noise. To address this challenge, we investigate a hybrid platform composed of two identical three-level atoms in a V-type configuration coupled to a single-mode cavity field prepared in a squeezed coherent state. Using the Lindblad master equation, we numerically simulate the system dynamics, allowing a rigorous treatment of coherent atom–field interactions, interatomic couplings, and cavity losses. Our analysis reveals that squeezing introduces nonclassical correlations that enhance field coherence and support the generation of entanglement under specific regimes. Strong interatomic coupling stabilizes entanglement, while squeezing mitigates decoherence-induced losses. Conversely, large photon amplitudes and cavity dissipation degrade both coherence and bipartite correlations. Quantum steering emerges as the most fragile correlation, yet its persistence can be moderately extended through squeezing. These results identify squeezing and interatomic interactions as complementary resources for optimizing coherence, entanglement, and steering, offering practical strategies for robust quantum communication, information processing, and engineered nonclassical states.
Abstract We investigate the robustness of Einstein–Podolsky–Rosen (EPR) steering, nonlocality, and quantum coherence in a bipartite atomic system coupled to cavity fields under the influence of decoherence. The system consists of two non-interacting atoms, where each atom is confined within a cavity that interacts with another cavity field, which plays a crucial role in governing the dynamical evolution of two atoms. Through a combination of analytical and numerical investigations, we demonstrate that quantum steering, Bell nonlocality, and coherence can be not only preserved but also enhanced by appropriately tuning the cavity–cavity interaction strength, effectively mitigating environmental decoherence and extending the coherence lifetime of the system. Our results reveal that, under optimal conditions, steering, nonlocality, and coherence remain resilient against decoherence over extended timescales. These findings offer valuable insights into the controlled manipulation of quantum resources in open quantum systems and have significant implications for quantum information processing and secure communication technologies.
This work investigates the emergence of Non-classical Features in a pump-free hybrid atom-optomechanical system, addressing key limitations of conventional platforms that rely on strong coherent driving and are highly vulnerable to thermal decoherence. We propose a novel architecture in which a squeezed vacuum reservoir acts as a pre-correlated quantum environment, enabling the deterministic generation and stabilization of nonclassical correlations without the need for an external laser pump. By exploiting reservoir-engineered interactions, the system supports robust quadrature squeezing and multipartite entanglement across a wide range of operational parameters. Our analysis demonstrates that the hybrid system achieves significant squeezing levels approaching 90%, while simultaneously satisfying the DGCZ inseparability criterion, confirming the presence of strong continuous-variable entanglement. Importantly, these nonclassical signatures remain resilient under extreme thermal conditions, withstanding thermal occupancies as high as (nth = 1500), which substantially exceeds the tolerance of traditional laser-driven optomechanical systems. The underlying mechanism is attributed to passive correlation injection from the engineered reservoir, which effectively suppresses thermal noise and enhances quantum coherence even in weak-coupling and low-power regimes. This eliminates the need for active pumping, thereby reducing energy consumption and experimental complexity. Furthermore, the hybrid atom-optomechanical configuration introduces additional tunability through atomic gain and population inversion, thereby allowing flexible control over system dynamics and correlation properties. Overall, the proposed scheme establishes a scalable and energy-efficient pathway toward realizing robust quantum correlations in realistic noisy environments. It opens new prospects for cryogen-free quantum technologies, including quantum-enhanced sensing, precision metrology, and long-distance entanglement distribution.
Abstract We introduce a novel scheme for achieving quantum entanglement and Einstein–Podolsky–Rosen (EPR) steering between an atomic ensemble and a mechanical oscillator within a hybrid atom–optomechanical system. The system comprises an optical cavity, a two-level atomic ensemble and a mechanical resonator that possesses Duffing nonlinearity. The interaction between these components is mediated by the cavity mode, which is driven by an external laser. Our findings indicate that optimizing the coupling strengths between photons and phonons, as well as between atoms and the cavity, leads to maximal entanglement and EPR steering. The amplitude of the driving laser plays a pivotal role in enhancing the coupling between photons and phonons, and the system maintains robust entanglement and EPR steering even under high dissipation, thereby mitigating the constraints on initial conditions and parameter precision. Remarkably, the Duffing nonlinearity enhances the system’s resistance to thermal noise, ensuring its stability and entanglement protection. Our analysis of EPR steering conditions reveals that the party with lower dissipation exhibits superior stability and a propensity to steer the party with higher dissipation. These discoveries offer novel perspectives for advancing quantum information processing and communication technologies.
Abstract Quantum resources such as entanglement and coherence are the holy grail for modern quantum technologies. Although the unwanted environmental effects tackle quantum information processing tasks, suprisingly these key quantum resources may be protected and even enhanced by the implementation of some special hybrid open quantum systems. Here, we aim to show how a dissipative atom-cavity-system can be accomplished to generate enhanced quantum resources. To do so, we consider a couple of dissipative cavities, where each one contains two effective two-level atoms interacting with a single-mode cavity field. In practical applications, a classical laser field may be applied to drive each atomic subsystem. After driving the system, a Bell-state measurement is performed on the output of the system to quantify the entanglement and coherence. The obtained results reveal that the remote entanglement and coherence between the atoms existing inside the two distant cavities are not only enhanced, but can be stabilized, even under the action of dissipation. In contrast, the local entanglement between two atoms inside each dissipative cavity attenuates due to the presence of unwanted environmental effects. Nevertheless, the local coherence may show the same behavior as the remote coherence. Besides, the system provides the steady state entanglement in various interaction regimes, particularly in the strong atom-cavity coupling and with relatively large detuning. More interestingly, our numerical analyses demonstrate that the system may show a memory effect due to the fact that the death and revival of the entanglement take place during the interaction. Our proposed model may find potential applications for the implementation of long distance quantum networks. In particular, it facilitates the distribution of quantum resources between the nodes of large-scale quantum networks for secure communication.
Abstract We investigate the steady-state photon statistics and quantum properties of a cascade three-level atom coupled to a two-mode squeezed-vacuum reservoir. The mean photon number, photon-number correlations, second-order coherence, and quadrature fluctuations are examined as functions of the stimulated-emission decay constant and the squeezing parameter. The system exhibits two distinct regimes: a squeezing-dominated regime, governed by reservoir-induced correlations, and a cavity-dynamics-dominated regime, characterized by strong gain–loss competition. Enhanced squeezing increases photon generation, intermodal correlations, and intracavity energy through correlated photon-pair injection while reducing vacuum fluctuations. Conversely, stronger stimulated emission induces nonlinear amplification, asymmetric photon distributions, and sequential emission dynamics. A transition from super-Poissonian to sub-Poissonian statistics is observed, indicating the coexistence of photon antibunching and continuous-variable quantum correlations. Furthermore, atom–cavity interactions modify the generalized uncertainty bounds, revealing fundamental limitations on achievable squeezing imposed by higher-order noise processes. These findings demonstrate that engineered reservoirs and cascade atomic systems provide versatile control of nonclassical light for quantum communication, precision metrology, and continuousvariable quantum information processing.
Engineering atom-atom interactions is essential both for controlling novel phases of matter and for efficient preparation of many-body entangled states, which are key resources in quantum communication, computation, and metrology. In this work, we propose a scheme to tailor these interactions by coupling driven atom pairs to optical cavity photons via a molecular state in the dispersive regime, resulting in an effective photon-field-dependent potential. As an illustrative example, by analyzing the quantum Fisher information, we show that such induced interactions can generate robust many-body entanglement in two-mode ultracold bosons in an optical cavity. By tuning the photon-induced interactions through the cavity drive, we identify conditions for preparing highly entangled states on timescales that mitigate decoherence due to photon loss. Our results show that entanglement formation rate scales strongly with both photon and atom number, dramatically reducing the timescale compared to bare atomic interactions. We also identify an optimal measurement for exploiting the metrological potential of the atomic state in an interferometric protocol with significant photon losses, saturating the quantum Cramer-Rao lower bound. Furthermore, we show that despite these losses the atomic state exhibits strong Bell correlations. Our results pave the way for engineering atom-atom interactions to study novel phases of light and matter in hybrid atom-photon systems, as well as for tailoring complex quantum states for new quantum technology protocols and fundamental tests of quantum mechanics.