We study the time evolution of three quantifiers of nonclassical correlations, namely uncertainty-induced nonlocality (UIN), trace distance discord (TDD), and logarithmic negativity (LN), in a hybrid spin–cavity system with anisotropic XY interactions and two-photon spin-field coupling. We examine how the interaction parameters, including the anisotropy strength, initial photon number, spin–cavity coupling, spin–spin interaction, and spin–cavity detuning, influence the resulting two-qubit correlations. Our results show that both spin–cavity and spin–spin couplings can efficiently generate UIN, TDD, and entanglement, each exhibiting distinct oscillatory features, and we further evaluate the robustness of these features as the other interaction parameters increase. In the presence of cavity dissipation and spontaneous emission, entanglement is rapidly suppressed and may undergo entanglement sudden death, whereas UIN and TDD remain noticeably nonzero over longer times despite the damping of their oscillations. Overall, our findings provide a comparative characterization of entanglement and discord-like correlations in a dissipative spin–cavity platform and highlight the greater persistence of UIN- and TDD-type correlations within the present dissipative framework.
We study the time evolution of three quantifiers of nonclassical correlations, namely uncertainty-induced nonlocality (UIN), trace distance discord (TDD), and logarithmic negativity (LN), in a hybrid spin–cavity system with anisotropic XY interactions and two-photon spin-field coupling. We examine how the interaction parameters, including the anisotropy strength, initial photon number, spin–cavity coupling, spin–spin interaction, and spin–cavity detuning, influence the resulting two-qubit correlations. Our results show that both spin–cavity and spin–spin couplings can efficiently generate UIN, TDD, and entanglement, each exhibiting distinct oscillatory features, and we further evaluate the robustness of these features as the other interaction parameters increase. In the presence of cavity dissipation and spontaneous emission, entanglement is rapidly suppressed and may undergo entanglement sudden death, whereas UIN and TDD remain noticeably nonzero over longer times despite the damping of their oscillations. Overall, our findings provide a comparative characterization of entanglement and discord-like correlations in a dissipative spin–cavity platform and highlight the greater persistence of UIN- and TDD-type correlations within the present dissipative framework.
In this paper, we investigate the time evolution of quantum correlations in a two-qubit system influenced by an optical channel. The system?s dynamics are analyzed in terms of concurrence (CN), Bell non-locality (BN), and trace distance discord (TDD), which quantify entanglement, non-local correlations, and quantum discord, respectively. Our model explores the impact of key parameters such as the beam-splitter angle, ?, channel parameter, ?, and angular frequency, ?, on these quantum correlations. The results show that CN and BN exhibit oscillatory behavior with periodic revivals, but tend to decay more rapidly under noisy conditions. Conversely, TDD demonstrates greater robustness, persisting even when CN and BN collapse, indicating the survival of quantum correlations in separable states. Higher noise strength and angular frequencies induce faster oscillations and revivals across all measures, with systems prepared with stronger initial quantum correlations showing increased resilience. This study highlights the robustness of quantum discord in noisy environments and its potential role in quantum information processing, even in the absence of entanglement.
Abstract An analytical solution for the dissipative system of two charge qubits located in an SC-cavity field is obtained in the dispersive regime. Therefore, the quantum correlation of the trace distance discord, the Bell function and the logarithmic negativity are investigated. The sensitivity of the correlation measures are investigated under the physical parameters of the phase damping and the qubit distribution angle of the initial symmetric/non-symmetric Bell-state, whereby correlation phenomena, such as the oscillatory behavior, disappearance/appearance and the collapses/revivals, are proven to demonstrate noticeable changes and high sensitivity to these physical parameters. It is shown that the unitary cavity-qubit interaction leads to the generation of quantum correlations periodically with different amplitudes and oscillations which depend on the initial two-qubit state and its distribution angle. The increase of the two-qubit phase damping leads to the complete disappearance of the generated trace distance, Bell function and log-negativity correlations.
We investigate quantum correlations in a hybrid qubit-qutrit system subject to both axial and planar single-ion anisotropies, dipolar spin-spin interactions, and Dzyaloshinskii-Moriya (DM) coupling. Using Negativity, Measurement-Induced Non-locality (MIN), Uncertainty-Induced Nonlocality (UIN), and Bell nonlocality (as quantified by the CHSH inequality) as measures, we analyze the interplay between anisotropy parameters, magnetic fields, and temperature on the survival of quantum correlations. Our results demonstrate that Bell nonlocality and entanglement (Negativity) are highly sensitive to temperature and anisotropy, exhibiting sudden death under thermal noise, whereas MIN and UIN are significantly more robust. In particular, these discord-like and information-theoretic measures provide the largest baseline and persist even in parameter regions where entanglement vanishes, highlighting their suitability as a quantumness witness in realistic conditions. Notably, our Bell nonlocality study is tailored to the asymmetric qubit-qutrit setting by exploiting a recently developed qubit-qudit CHSH maximization framework. However, Bell nonlocality is confirmed to be the most fragile, surviving only in narrow parameter windows at low temperature. A key finding of this work is that we observe the fragility hierarchy: Bell nonlocality ⊆ Negativity ⊆ UIN(MIN) in the qubit-qutrit setting. These results provide deeper insight into the relative robustness of distinct quantum resources in anisotropic qubit-qutrit models, suggesting that quantum discord-like measures, such as MIN and UIN, may serve as more practical resources than entanglement for quantum information tasks in thermally active spin systems.
We investigate the dynamics of key quantum correlations - Negativity (NG), Quantum Discord (QD), and Quantum-Memory-Assisted Entropic Uncertainty (QM-EUR) - in a bipartite two-qubit system under the influence of external pulses and various decoherence channels, including amplitude damping (gamma_amp), pure dephasing (gamma_deph), and pulse-induced dephasing (G), while different regimes of inter-qubit coupling (Jzz, Jxx), qubit energy splitting (epsilon), and pulse parameters (A_pulse, beta_pulse) are explored. Our results show that inter-qubit coupling and energy splitting epsilon significantly influence the dynamics, producing pronounced oscillations in the weak-coupling regime and protecting pre-existing entanglement in the strong-coupling regime. NG is the most sensitive, QD persists longer revealing nonclassical correlations independent of entanglement, and QM-EUR reflects residual quantum memory and entropic uncertainty, showing that quantum signatures survive even when NG and QD are weak. Pulse amplitude and width effectively control the generation and dissipation of correlations, while the intensity of pulse-induced dephasing modulates the balance between sustained oscillations and rapid decoherence. The initial state also plays a crucial role: a partially entangled initial state is more resilient to perturbations, preserving correlations over time, whereas a separable state exhibits cycles of entanglement creation and destruction. Thus, by adjusting system parameters, it is possible to control the stability and lifetime of correlations and coherence, providing a framework to optimize quantum systems for applications requiring both strong entanglement and long-lasting coherence, such as quantum computing and secure communication.
In this paper, we explore the dynamics of quantum correlations in an isolated physical quantum dot under the influence of intrinsic decoherence (ID). We characterize quantum correlations in the quantum dot system using Concurrence to capture the amount of entanglement, and we use Trace Distance Discord (TDD) and Local Quantum Uncertainty (LQU) to measure nonclassical correlations. Likewise, we investigate the effect of ID on the temporal evolution of these quantifiers. In particular, the behavior of the two discord-like quantifiers in terms of the system parameters and the ID rate is investigated and analyzed in detail. We found that TDD and LQU behave similarly for different parameters characterizing the considered system and that TDD is more resistant than Concurrence and LQU against the ID effects. Our results also show that the robustness of quantum correlations can be modulated by adjusting the ID rate, quantum dot physical properties and initial conditions.
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.