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arXiv:2412.19046 · Physical Review A

Thermal quantum correlations of a single electron in a double quantum dot with transverse magnetic field

Vinicius Leitão, Onofre Rojas, Moisés Rojas

Published Jul 17, 2025• 2 citations
arXivHTMLPDF

Abstract

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.

DOI
10.1103/gj3r-n25m

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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.
In this work, we study the thermal quantum coherence and fidelity in a two-level system with spin-orbit coupling. The proposed model involves a single electron in a double quantum dot with Rashba spin-orbit coupling in the presence of an external magnetic field. In our scenario, the thermal entanglement of the single electron is driven by the charge and spin qubits, the latter controlled by Rashba coupling. Analytical expressions are obtained for thermal concurrence and correlated coherence using the density matrix formalism. The main goal of this work is to provide a good understanding of the effects of temperature and several parameters in quantum coherence. In addition, our findings show that we can use the Rashba coupling to tune the thermal entanglement, quantum coherence, and the thermal fidelity behavior of the system. Moreover, we focus on the role played by thermal entanglement and correlated coherence responsible for quantum correlations. We observe that the correlated coherence is more robust than the thermal entanglement in all cases, so quantum algorithms based only on correlated coherence may be stronger than those based on entanglement.
Abstract In this work, the thermal quantum correlations in two coupled double semiconductor charge qubits are investigated. This is carried out by deriving analytical expressions for both the thermal concurrence and the correlated coherence. The effects of the tunneling parameters, the Coulomb interaction, and the temperature on the thermal entanglement and on the correlated coherence are studied in detail. It is found that the Coulomb potential plays an important role in the thermal entanglement and in the correlated coherence of the system. The results also indicate that the Coulomb potential can be used for significant enhancement of the thermal entanglement and quantum coherence. One interesting aspect is that the correlated coherence capture all the thermal entanglement at low temperatures, that is, the local coherences are totally transferred to the thermal entanglement. Finally, the role played by thermal entanglement and the correlated coherence responsible for quantum correlations are focused on. It is shown that in all cases, the correlated coherence is more robust than the thermal entanglement so that quantum algorithms based only on correlated coherence may be more robust than those based on entanglement.
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.
Abstract In this paper, we investigate the dynamics of quantum resources (QRs) in a double quantum dot (DQD) system subject to thermal fluctuations. We explore the effects of temperature, Rashba spin–orbit interaction (RSOI), and other system parameters on QR in this system. We use three quantum measures in this context: linear entropy, first-order coherence, and entanglement quantified by concurrence. The results demonstrate the detrimental effects of thermal noise and that an increase in the Zeeman splitting exacerbates this degradation of QR. The findings further reveal that careful tuning of the RSOI can enhance and preserve thermal quantum correlations. Interestingly, first-order coherence persists at higher temperatures than entanglement, indicating that coherence-based tasks and protocols could be more resilient in spin-qubit arrays. Unlike entanglement and coherence, linear entropy increases with temperature and Rashba coupling, suggesting that the RSOI increases the mixedness of the thermal state in the DQD system.
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.