Abstract Double quantum dot (DQD) systems are highly regarded as promising candidates for advancements in the fields of quantum computing and quantum information processing. In this work, we investigate the behaviour of quantum correlations (QCs) in a system of two DQDs, AlGaAs/GaAs under various parameters such as temperature, energy offsets, coupling strength, and magnetic fields. We employ uncertainty-induced nonlocality and Bell nonlocality to quantify QC and logarithmic negativity to measure entanglement in the considered physical system. The findings demonstrate that QCs are significantly influenced by noisy equilibrium temperature and system parameters. In particular, lower temperatures enhance QCs, whereas higher temperatures result in a decrease due to thermal effects. In addition, the magnetic fields have a profound influence on the conditions of resonance. We also show that maximum QCs occur at resonance conditions with no energy offset between each DQD. However, introducing an energy offset or too-strong coupling reduces these correlations. Finally, our findings provide an understanding of the behaviour of entanglement and quantum nonlocality in DQD systems, offering potential implications for quantum technologies.
Abstract Double quantum dot (DQD) systems are highly regarded as promising candidates for advancements in the fields of quantum computing and quantum information processing. In this work, we investigate the behaviour of quantum correlations (QCs) in a system of two DQDs, AlGaAs/GaAs under various parameters such as temperature, energy offsets, coupling strength, and magnetic fields. We employ uncertainty-induced nonlocality and Bell nonlocality to quantify QC and logarithmic negativity to measure entanglement in the considered physical system. The findings demonstrate that QCs are significantly influenced by noisy equilibrium temperature and system parameters. In particular, lower temperatures enhance QCs, whereas higher temperatures result in a decrease due to thermal effects. In addition, the magnetic fields have a profound influence on the conditions of resonance. We also show that maximum QCs occur at resonance conditions with no energy offset between each DQD. However, introducing an energy offset or too-strong coupling reduces these correlations. Finally, our findings provide an understanding of the behaviour of entanglement and quantum nonlocality in DQD systems, offering potential implications for quantum technologies.
Abstract In this work, we mainly study Bell nonlocality and quantum steerability of two-coupled double quantum dots (DQDs) system via local filtering operation. We compare and analyze the influence of the Coulomb potential, temperature, tunneling parameter and local filtering operation on quantum steering and Bell nonlocality in the system. The results show that quantum steering and nonlocality first increase and then decrease but never vanish even for the stronger value of the Coulomb potential. Quantum steering and Bell nonlocality would degrade with the increase of temperature. The filtering process does not increase the degree of steerability, but decreases the range of quantum steerability. In addition, it is noteworthy that a peculiar phenomenon exists: the Einstein–Podolsky–Rosen (EPR) steering asymmetry between Alice and Bob first increase, then decrease to zero and finally increases as the tunneling strength increases. However, this phenomenon does not appear with no operation between Alice and Bob.
We study bipartite entanglement, quantum coherence, and linear-entropy-based distance in a semiconductor double quantum dot (DQD) hosting a single electron, subject to longitudinal Zeeman splitting, a transverse magnetic field gradient, and thermal fluctuations. In this single-electron system, modeled as a two-qubit system, intrinsic correlations arise from the interplay between the charge-localization and spin degrees of freedom. Entanglement is quantified via the Bures distance, coherence through the Hellinger distance, and linear-entropy-based distance is used as a quantitative measure to characterize the purity of the corresponding quantum thermal state. Our results demonstrate how temperature T, the strength of applied magnetic fields, and the intrinsic DQD parameters shape the behavior of these quantum resources (QR), revealing that careful adjustment of the DQD parameters and the intensities of the two perpendicular external magnetic fields provides a practical handle for controlling the quantum properties of the system and preserving quantum resources against the detrimental effects of thermal noise. We further show that Hellinger coherence is more robust than entanglement against thermal noise, underscoring its potential as a reliable quantum resource in solid-state quantum information platforms.
This work explores the generation and robustness dynamics of coupled double quantum dots using uncertainty-induced (UI) nonlocality, maximum Bell-CHSH inequality, and log-negativity with intrinsic-decoherence. This study examines the generation of Bell-CHSH nonlocality, UI-nonlocality, and log-negativity entanglement using a separable two-double-quantum-dots state. Enhancing these features is achieved by tuning intrinsic decoherence and dot interaction strengths, highlighting their potential for creating robust quantum correlations. The two-double-quantum-dots correlated states can be produced and enhanced by increasing the pair-dots tunneling couplings and Coulomb-two-electrons interactions. The decoherence effect acceleration depends on Coulomb-two-electrons interactions and the pair-dots tunneling coupling. For a maximally entangled state, the robustness dynamics of the initial maximal Bell-CHSH-nonlocality, UI-nonlocality, and log-negativity’s entanglement, is explored against the two-double-quantum-dots interactions and the decoherence effects.
In this paper we investigate the thermal quantum correlations in a semiconductor double-quantum-dot system. The device comprises a single electron in a double quantum dot subjected to a longitudinal-magnetic-field and a transverse-magnetic-field gradient. The thermal entanglement of the single electron is driven by the charge and spin qubits. Employing the density-matrix formalism, we derive analytical expressions for thermal concurrence and correlated coherence, providing a comprehensive analysis of how temperature and various system parameters influence quantum coherence. Our results demonstrate that the transverse magnetic field serves as a tunable parameter for controlling thermal entanglement and quantum coherence. We also highlight the roles of thermal entanglement and correlated coherence in generating quantum correlations, noting that thermal correlated coherence is consistently more robust than thermal entanglement. This suggests that quantum algorithms based solely on correlated coherence might be more resilient than those relying on entanglement.
Abstract Quantum batteries (QBs) have been proposed as devices that exploit the advantage of quantum resources, such as coherence and entanglement, to improve charging performance. In this study, we theoretically investigate a QB model based on two coupled double quantum dots (TDQDs) implemented on the well-established AlGaAs/GaAs platform for quantum nanodevice fabrication. Using ergotropy and power as key performance indicators, we examine how various system parameters affect the energy performance of the QB. Our study begins with an analysis of quantum resources in the QB’s initial state, followed by an examination of how control parameters that influence these resources impact the modeling and performance of the battery. Our results demonstrate that increasing the energy offset improves ergotropy and power but reduces quantum correlations. Conversely, increasing tunneling couplings leads to a non-monotonic variation in the maximum ergotropy, which peaks at a certain point before decreasing, closely following the behavior of quantum entanglement despite continued growth in quantum coherence. This highlights the feasibility of efficient energy storage in quantum dots (QDs) for use in quantum batteries (QBs). It also emphasizes that coherence alone is insufficient for optimal performance and that other quantum correlations are necessary and must be carefully considered to fully exploit the potential of quantum resources.
This study investigates the dynamics of two-qubit correlations in a double quantum dot (QD) containing an electron and two charge-spin configurations under the influence of Rashba interaction, the Dzyaloshinsky–Moriya interaction, and an external magnetic field. The dynamics of two-qubit correlations, particularly those of local quantum Fisher information (LQFI) and local quantum uncertainty (LQU), are compared with those of log negativity. The correlation dynamics are analysed under the effects of Dzyaloshinsky–Moriya interaction, Rashba spin–orbit coupling, electron tunnelling strength, Zeeman spin-splitting coupling, and intrinsic decoherence. Importantly, in the absence of intrinsic electron QD qubit decoherence, it is found that weak couplings within the electron QD qubit system have a high capacity to create equal LQFI and LQU two-qubit correlations, as well as log-negativity entanglement. Furthermore, it is found that an increase in Zeeman spin splitting and the tunnelling effect of two electrons decreases the ability of the other couplings, DM spin–orbit and Rashba spin–orbit interactions, to generate Wigner–Yanase–Fisher correlation and entanglement, and the opposite is also true. The generation of electron-QD qubit correlations exhibits decaying oscillatory dynamics, especially when decoherence is considered. Additionally, the LQFI and LQU display different correlations, and the sudden death and birth phenomena of entanglement occur. Moreover, the phenomena of decaying oscillatory dynamics, as well as the sudden death and birth of entanglement, depend on the electron-QD-qubit couplings. These electron-QD-qubit correlations provide the quantum dot system with promising features for establishing quantum technologies.