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Modern Physics Letters A

Geometric quantum resources and linear entropy in a double quantum dot under thermal and magnetic field effects

Aicha Chouiba, Reem Altuijri, Abdel‐Haleem Abdel‐Aty, Mostafa Mansour

Published Aug 21, 2026• 0 citations
Publisher

Abstract

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.

DOI
10.1142/s0217732326502378

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This work examines the thermal dynamics of basis-independent quantum coherence and correlation-based quantum resources for two dipole-dipole-coupled electrons confined in spatially separated quantum-dot (QD) molecules. Single-dot quantum superpositions and inter-subsystem coherence are characterized by using localized and collective coherence. Quantum correlations between the two double quantum dots are quantified by employing Bures distance entanglement, Local quantum uncertainty (LQU), and local quantum Fisher Information (LQFI). The findings show that dipole-dipole coupling KKK is the most effective protective parameter, extending the entanglement sudden death temperature, diminishing the local quantum superpositions and enhancing the collective coherence. The dipole-dipole interaction has also a crucial impact on protecting LQU and LQFI beyond the entanglement sudden death temperature. Coulomb repulsion JJJ reinforces this protection through an independent channel, projecting the thermal state onto the entangled {∣0A1B⟩,∣1A0B⟩}\{|0_A 1_B\rangle,|1_A 0_B\rangle\}{∣0A​1B​⟩,∣1A​0B​⟩} subspace; their combined action is required to approach the entanglement maximum, and it enhances collective coherence and extends the temperature range over which LQU and LQFI remain appreciable. Energy detuning ε\varepsilonε can enhance localized coherence but paradoxically accelerates the entanglement sudden death and quenches LQU and LQFI by weakening two-body correlations. Inter-dot tunneling ΓΓΓ enhances local superpositions at low temperature, but it reduces collective coherence, lowers the entanglement sudden death temperature, and disrupts other nonclassical correlations.