The preservation of quantum correlations requires optimal procedures and the proper design of the transmitting channels. In this regard, we address designing a hybrid channel comprising a single-mode cavity accompanied by a super-Gaussian beam and local dephasing parts based on the dynamics of quantum characteristics. We choose two-level atoms and various functions such as traced-distance discord, concurrence, and local-quantum uncertainty to analyze the effectiveness of the hybrid channel to preserve quantum correlations along with entropy suppression discussed using linear entropy. The joint configuration of the considered fields is found to not only preserve but also generate quantum correlations even in the presence of local dephasing. Most importantly, within certain limits, the proposed channel can be readily regulated to generate maximal quantum correlations and complete suppression of the disorder. Besides, compared to the individual parts, mixing the Fock state cavity, super-Gaussian beam, and local dephasing remains a resourceful choice for the prolonged quantum correlations' preservation. Finally, we present an interrelationship between the considered two-qubit correlations' functions, showing the deviation between each two correlations and of the considered state from maximal entanglement under the influence of the assumed hybrid channel.
The preservation of quantum correlations requires optimal procedures and the proper design of the transmitting channels. In this regard, we address designing a hybrid channel comprising a single-mode cavity accompanied by a super-Gaussian beam and local dephasing parts based on the dynamics of quantum characteristics. We choose two-level atoms and various functions such as traced-distance discord, concurrence, and local-quantum uncertainty to analyze the effectiveness of the hybrid channel to preserve quantum correlations along with entropy suppression discussed using linear entropy. The joint configuration of the considered fields is found to not only preserve but also generate quantum correlations even in the presence of local dephasing. Most importantly, within certain limits, the proposed channel can be readily regulated to generate maximal quantum correlations and complete suppression of the disorder. Besides, compared to the individual parts, mixing the Fock state cavity, super-Gaussian beam, and local dephasing remains a resourceful choice for the prolonged quantum correlations' preservation. Finally, we present an interrelationship between the considered two-qubit correlations' functions, showing the deviation between each two correlations and of the considered state from maximal entanglement under the influence of the assumed hybrid channel.
Effective information transmission is a central element in quantum information protocols, but the quest for optimal efficiency in channels with symmetrical characteristics remains a prominent challenge in quantum information science. In light of this challenge, we introduce a hybrid channel that encompasses thermal, magnetic, and local components, each simultaneously endowed with characteristics that enhance and diminish quantum correlations. To investigate the symmetry of this hybrid channel, we explored the quantum correlations of a simple two-qubit Heisenberg spin state, quantified using measures such as negativity, ℓ1-norm coherence, entropic uncertainty, and entropy functions. Our findings revealed that the hybrid channel can be adeptly tailored to preserve quantum correlations, surpassing the capabilities of its individual components. We also identified optimal parameterizations to attain maximum entanglement from mixed entangled/separable states, even in the presence of local dephasing. Notably, various parameters and quantum features, including non-Markovianity, exhibited distinct behaviors in the context of this hybrid channel. Ultimately, we discuss potential experimental applications of this configuration.
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.
We address the effective generation of thermal non-classical correlations in two two-level atoms when exposed to a Fock-state cavity incorporated with classical decoherence effects. Using Bell non-locality, quantum coherence, and concurrence, we investigate the generation maps of non-locality, coherence, and entanglement. We show that the two atoms are initially separable, however, they become coherent and entangled within a short period of time when exploited with the Fock-state cavity. Interestingly, the Fock-state cavity shows dominant traits for the complete suppression of the classical decoherence effects. However, the decoherence effects appear initially and delay the generation of non-classical correlations. In addition, the generation delay of non-classical correlations is observed to be highly affected when the atom-cavity configuration is considered in a strong coupling regime. Compared to the entanglement and non-locality, the Fock-state cavity develops quantum coherence faster in the two-level systems. Finally, we also discuss the optimal feature settings of the Fock-state cavity, related significance, and experimental prospects of the study.
Abstract We investigate a hybrid qubit–qutrit system exposed to both a magnetic field and classical dephasing noise. The quantum system’s characteristics encompass diverse parameters, including spin-exchange interaction, dephasing, and the magnetic field. To incorporate thermal effects, we employ the system’s Hamiltonian to generate an initial qubit–qutrit density matrix within the framework of the Gibbs density operator. Furthermore, we model dephasing effects on the initial thermal state of the system using an Ornstein–Uhlenbeck process. We employ geometric discord, negativity, and entropic coherence functions to depict the quantum correlations across various parameter settings. Our results reveal that initially, quantum correlations attain non-maximal values, with their dynamics intricately reliant on the underlying system parameters. Specifically, when the system is primarily characterized by the magnetic field, we observe heightened levels of quantum correlations. Additionally, temperature-based characterization is found to have the most detrimental effect on the state. Geometric discord is observed to capture a higher degree of quantum correlations, albeit saturating rapidly at zero compared to entanglement and coherence. Finally, we investigated the effects of common environmental coupling and more pronounced non-Markovian dynamics in the system, revealing an enhanced preservation of quantum correlations. These modifications allow for prolonged coherence and entanglement, underscoring the potential of structured environmental interactions to mitigate decoherence effects and sustain quantum correlations over time.
The uncertainty principle limits the ability for observer to precisely measure two incompatible observables, and plays a crucial role in quantum precision measurement in the quantum information science. When quantum systems interact with their surroundings, they inevitably result in decoherence, which increases the uncertainty of the system. In the process of quantum information processing, the effective regulation of uncertainty becomes a key problem that needs to be solved. In this work, we investigate the quantum-memory-assisted entropic uncertainty relation of a two-qubit system under correlated channels with dephasing colored noise. We demonstrate that it is possible to control the entropic uncertainty, U, and its lower bound, Ub, by combining correlations between successive uses of channels and the non-Markovianity of the dynamical evolution. Firstly, the evolutionary characteristics of the trace distance are employed to distinguish between Markovianity and non-Markovianity of the channel. Subsequently, the system is selected to be either a maximally entangled state or separated state initially. By adjusting the strength η of the correlations, we find that with the increase of η, the entropic uncertainty and its lower bound decrease. Especially, if the channel is fully correlated (η = 1), the entropic uncertainty and its lower bound remain constant under the channel, indicating that decoherence is completely suppressed. A comparison of Markovian channel with non-Markovian channel reveals that the entropic uncertainty and its lower bound exhibit oscillatory behaviour under non-Markovian channels. The combination of correlations and non-Markovianity of the channel demonstrates that the entropic uncertainty and its lower bound can be reduced under fully correlated channels where the non-Markovianity has no effect. This is because fully correlated channels suppress decoherence to a greatest extent. Under partially correlated channels, the combination of correlations and non-Markovianity can more effectively reduce the entropic uncertainty and its lower bound. Under such channels, correlations of the channel reduce the entropic uncertainty and its lower bound during the whole evolution, while the non-Markovianity contributes to their oscillations and reduce them in some specific time. Furthermore, the results show that the entropic uncertainty and its lower bound reach steady values that depend only on the strength of the correlations after long-time evolution. In other words, the stronger the correlations, the lower the entropy uncertainty and its lower bound of steady states will be. Finally, we analyse the physical nature of the decrease of the entropic uncertainty and its lower bound, and it is found that the decrease of the entropic uncertainty and its lower bound originate from the increase of the quantum correlations in the system.
Abstract In this paper, we examine the dynamics of quantum correlations in two noninteractive two-level atoms coupled to two separate identical thermal reservoirs. The two atoms are initially produced in a Gisin state, which is a blend of a maximally entangled two-qubit state and a separable mixed state. Quantum entanglement is measured by logarithmic negativity, while the nonclassical correlations are characterized by trace distance discord and local quantum uncertainty. Using the mean photon number of reservoirs and spontaneous emission rates of atoms as inputs, we explore how these quantum resources behave. Consequently, we demonstrate that the dynamics of quantum entanglement and quantum correlations depend upon the parameters driving the system. Significantly, we further demonstrate that specific parameters may be tweaked to preserve the quantum resources in the system. The results give a full grasp of the quantum features of such a two-level atomic system, showing capabilities to construct quantum technology.