ABSTRACT This research examines the dynamics of quantum correlations in a hybrid qubit–qutrit system subjected to an Ohmic noisy environment. While entanglement degradation in homogeneous systems is well‐documented, the behavior of disparate‐dimensional interfaces remains a critical challenge for the interoperability of future quantum networks. Using the negativity as a measure of entanglement, we analytically and numerically investigate how the spectral properties of the reservoir influence the system´s coherence. Our results reveal that the cut‐off frequency ω c acts as a fundamental control parameter: at low frequencies, it triggers non‐Markovian effects that effectively shield the system from entanglement sudden death, whereas high frequencies accelerate the transition to a purely dissipative regime. Furthermore, we demonstrate that strategic optimization of the coupling strength J and the entanglement parameter r can significantly enhance the robustness of hybrid correlations. The findings provide new methodological insights and practical guidelines for reservoir engineering, offering a framework to preserve quantum resources in high‐dimensional hybrid architectures.
ABSTRACT This research examines the dynamics of quantum correlations in a hybrid qubit–qutrit system subjected to an Ohmic noisy environment. While entanglement degradation in homogeneous systems is well‐documented, the behavior of disparate‐dimensional interfaces remains a critical challenge for the interoperability of future quantum networks. Using the negativity as a measure of entanglement, we analytically and numerically investigate how the spectral properties of the reservoir influence the system´s coherence. Our results reveal that the cut‐off frequency ω c acts as a fundamental control parameter: at low frequencies, it triggers non‐Markovian effects that effectively shield the system from entanglement sudden death, whereas high frequencies accelerate the transition to a purely dissipative regime. Furthermore, we demonstrate that strategic optimization of the coupling strength J and the entanglement parameter r can significantly enhance the robustness of hybrid correlations. The findings provide new methodological insights and practical guidelines for reservoir engineering, offering a framework to preserve quantum resources in high‐dimensional hybrid architectures.
We investigate the quantum correlations in an axially symmetric hybrid qubit-qutrit system subjected to different noisy environments. We first introduce a physical model and analyze its Hamiltonian structure, emphasizing the role of hybrid dimensionality and axial symmetry. The effects of decoherence are then examined under two local noise mechanisms, namely dephasing and phase-flip channels, acting on the qubit and qutrit subsystems in both symmetric and asymmetric configurations. Quantum correlations are quantified using negativity to capture entanglement and quantum discord based on linear entropy to characterize more general nonclassical correlations. Our results show that both thermal fluctuations and phase noise lead to a monotonic degradation of quantum correlations, with increasing temperature accelerating coherence loss and inducing entanglement sudden death at finite temperatures. While negativity vanishes abruptly under sufficiently strong noise, quantum discord persists beyond the entanglement threshold, revealing residual quantum correlations in mixed states. We further demonstrate that asymmetric noise configurations significantly enhance the robustness of both entanglement and discord by partially shielding coherence in the less affected subsystem. A comparative analysis reveals that phase-flip noise is more destructive than pure dephasing, leading to faster suppression of quantum correlations.
This study advances the theoretical understanding of decoherence mechanisms in open quantum systems by modelling entanglement dynamics under localised environmental interactions relevant to emerging quantum technologies in Tunisia. A unified analytical framework is developed that bridges Markovian and non-Markovian regimes, quantifying the resilience of bipartite entanglement against structured environmental noise. Considering a system of two non-interacting qubits coupled to a common bosonic reservoir, a generalised master equation incorporating a memory kernel is derived from a structured spectral density function with tunable ohmicity. An analytical expression for the time-dependent concurrence is obtained for an initial Bell state, revealing a crossover from monotonic decay to oscillatory behaviour with entanglement revivals as the reservoir cutoff frequency is lowered relative to the qubit splitting. In the sub-ohmic regime, entanglement decay is slower and revivals are more pronounced, demonstrating that the spectral density cutoff frequency acts as a control parameter for entanglement preservation. The framework incorporates a local noise temperature parameter to represent cryostat fluctuations typical of Tunisian laboratory conditions, allowing the model to capture the phenomenology of entanglement evolution under constraints of limited cryogenic infrastructure and higher ambient noise levels. Crucially, the results show that standard Markovian models systematically overestimate the rate of entanglement loss, particularly in sub-ohmic environments, and that non-Markovian memory effects can temporarily restore quantum correlations after periods of apparent death. These findings challenge the assumption that decoherence is irreversible, revealing a form of quantum memory that could be harnessed for error correction or state protection. The framework provides a practical tool for predicting coherence lifetimes in solid-state and photonic systems, offering a comparative benchmark for experimental platforms within Tunisia's nascent quantum optics community and informing the design of robust quantum information protocols in the North African research context.
Abstract The dynamics of open quantum systems under decoherence effects remain a hotly debated topic in the case of the practical deployment of quantum information processing. In this regard, we examine how the three-qubit mixed state is affected by changes in the cut-off frequency of the Ohmic spectral density in a harmonic reservoir. Specifically, the degree of quantum memory-assisted entropic uncertainty (QMA-EU), along with the entanglement, coherence, and purity of the system, is to be demonstrated. A thorough exercise is done to investigate any underlying relationship between the three-qubit quantum characteristics. We show that a harmonic reservoir controlled by Ohmic noise prevails a monotonic-like decay in the current case where, sooner or later, the state becomes completely disentangled, decoherent, and mixed. The QMA-EU has always been found to have an increasing function causing the quantum resourcefulness to be reduced. Although, there is no pathway to avoid the Ohmic noise consequences and complete decay, however, we provided parameterization which would lead to prolonged preservation of quantum correlations with time. Finally, we provide various settings for the tuning of cut-off frequency regarding the Ohmic type bath and state parameters on the initial as well as final levels of quantum features.
We study the dissipative dynamics of a hybrid qubit–qutrit system initially prepared in the interacting thermal (Gibbs) state of the full Hamiltonian and subsequently subjected to a non-Markovian amplitude-damping channel. To benchmark the persistence of nonclassical features in this noisy setting, we track four complementary quantum resources: entanglement via negativity (NEG), nonclassical correlations via geometric quantum discord (GQD), coherence via the [Formula: see text]-norm of coherence (LNC) and measurement-induced quantumness via local quantum uncertainty (LQU). We show that coherent exchange coupling g enhances both the initial magnitudes and lifetimes of all resources by strengthening qubit–qutrit hybridization, whereas strong dispersive (cross-Kerr) coupling [Formula: see text] suppresses thermal correlations already at [Formula: see text], thereby limiting the resources available before dissipation sets in. Environmental memory effects, controlled by the reservoir cutoff frequency, slow the decay and can induce some revival pattern–assisted decay, extending the operational time window slightly. Across a broad parameter range, coherence (LNC) is consistently the most robust resource, often persisting after entanglement and discord have decayed, indicating that coherence-based protocols may provide superior stability in noisy hybrid architectures.
Abstract We investigate the time evolution of quantum correlations of a hybrid qubit-qutrit system under the classical Ornstein-Uhlenbeck (OU) noise. Here we consider two different one-parameter families of qubit-qutrit states which independently interact with the non-Markovian reservoirs. A comparison with the Markovian dynamics reveals that for the same set of initial condition parameters, the non-Markovian behavior of the environment plays an important role in the enhancement of the survival time of quantum correlations. In addition, it is observed that the non-Markovian strength ( γ / Γ ) has a positive impact on the correlations time. For the initial separable states it is found that there is a finite time interval in which the geometric quantum discord is frozen despite the presence of a noisy environment and that interval can be further prolonged by using the non-Markovian property. Moreover, its decay can be significantly delayed .
Hybrid quantum systems integrating superconducting qubits and nitrogen-vacancy (NV) center qutrits are promising for quantum information processing but are vulnerable to environmental dephasing. This study investigates the distinct dynamical behaviors of three facets of quantumness — total nonclassical correlations (Local Quantum Uncertainty (LQU)), quantum superposition ([Formula: see text] norm of coherence), and entanglement (Negativity) — in such a qubit–qutrit hybrid system subjected to non-Markovian dephasing noise. We reveal a clear hierarchy of robustness: coherence exhibits remarkably persistent oscillations, LQU decays with damped oscillations to a stable non-zero baseline, while entanglement proves most fragile, suffering periodic sudden death. Our central finding is the uniquely constructive role of the direct qubit–qutrit coupling strength, which robustly enhances all three quantum resources. In contrast, most other system parameters either accelerate decoherence or have complex, non-monotonic effects. These results clarify the different resilience levels of quantum resources and identify key parameters for preserving quantumness in noisy hybrid systems.