In moderately strong magnetic fields, the difference in Land\'e $g$ factors in each of the dots of a two-electron double quantum dot (DQD) may induce oscillations between singlet and triplet states of an entangled pair and lead to a nonequilibrium electron spin polarization in the system. The calculated bipolar polarization reflects the strong spin correlation in the spatially separated pair of electrons that occupy almost degenerate states in a coupled DQD. We will show that this polarization may partially survive the rapid inhomogeneous decoherence caused by random nuclear magnetic fields.In moderately strong magnetic fields, the difference in Land\'e $g$ factors in each of the dots of a two-electron double quantum dot (DQD) may induce oscillations between singlet and triplet states of an entangled pair and lead to a nonequilibrium electron spin polarization in the system. The calculated bipolar polarization reflects the strong spin correlation in the spatially separated pair of electrons that occupy almost degenerate states in a coupled DQD. We will show that this polarization may partially survive the rapid inhomogeneous decoherence caused by random nuclear magnetic fields.

arXiv:cond-mat/0508566Physical Review BJul 20, 20063 citations

Magneto-Dynamics of a Double Quantum Dot System

Norman J. M. Horing, Désiré Miessein, L.Y. Chen

Bulletin of the American Physical SocietyMar 11, 20080 citations

Nonlocal correlations and entanglement in two coupled double quantum dots under external magnetic field

Hicham Ait Mansour, Aicha Chouiba, Mostafa Mansour +1 more

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.

Laser Physics LettersNov 6, 20248 citations

Quantum Magnetic Field Effects on the Spectrum of a Double Dot System

Norman J. M. Horing, Jay D. Mancini

Bulletin of the American Physical SocietyMar 15, 20100 citations

Zeeman coupling and Swap action in spin‐based diluted magnetic semiconductor quantum dot quantum computer

A. Hichri, S. Jaziri

We present theoretically the Zeeman coupling and exchange induced swap action in spin-based quantum dot quantum computer models in the presence of magnetic field. We study the valence and conduction band states in a double quantum dots made in diluted magnetic semiconductor. The later have been proven to be very useful in building an all-semiconductor platform for spintronics. Due to a strong p–d exchange interaction in diluted magnetic semiconductor (Cd0.57Mn0.43Te), the relative contribution of this components is strongly affected by an external magnetic field, a feature that is absent in non magnetic double quantum dots. We determine the energy spectrum and the swap time as a function of magnetic field and the inter dot distance within the Hund–Mulliken molecular-orbit approach and by including the Coulomb interaction.We present theoretically the Zeeman coupling and exchange induced swap action in spin-based quantum dot quantum computer models in the presence of magnetic field. We study the valence and conduction band states in a double quantum dots made in diluted magnetic semiconductor. The later have been proven to be very useful in building an all-semiconductor platform for spintronics. Due to a strong p–d exchange interaction in diluted magnetic semiconductor (Cd0.57Mn0.43Te), the relative contribution of this components is strongly affected by an external magnetic field, a feature that is absent in non magnetic double quantum dots. We determine the energy spectrum and the swap time as a function of magnetic field and the inter dot distance within the Hund–Mulliken molecular-orbit approach and by including the Coulomb interaction.

Physica status solidi. C, Conferences and critical reviews/Physica status solidi. C, Current topics in solid state physicsMar 29, 20040 citations

Anisotropic Spin Exchange in Coupled Quantum Dots

K. Foster, Layla Hormozi

APSMar 1, 20050 citations

In moderately strong magnetic fields, the difference in Land\'e

g

factors in each of the dots of a two-electron double quantum dot (DQD) may induce oscillations between singlet and triplet states of an entangled pair and lead to a nonequilibrium electron spin polarization in the system. The calculated bipolar polarization reflects the strong spin correlation in the spatially separated pair of electrons that occupy almost degenerate states in a coupled DQD. We will show that this polarization may partially survive the rapid inhomogeneous decoherence caused by random nuclear magnetic fields.