Spin-entangled electrons in solid-state systems

Burkard, Guido

doi:10.1088/0953-8984/19/23/233202

Cited by 36 publications

(35 citation statements)

References 112 publications

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“…[1][2][3][4][5][6] The experimental control over the electron spin in quantum dots has seen enormous progress, with lateral gated GaAs structures demonstrating the state of the art.…”

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confidence: 99%

Theory of single electron spin relaxation in Si/SiGe lateral coupled quantum dots

2011

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We investigate the spin relaxation induced by acoustic phonons in the presence of spin-orbit interactions in single electron Si/SiGe lateral coupled quantum dots. The relaxation rates are computed numerically in single and double quantum dots, in in-plane and perpendicular magnetic fields. The deformation potential of acoustic phonons is taken into account for both transverse and longitudinal polarizations and their contributions to the total relaxation rate are discussed with respect to the dilatation and shear potential constants. We find that in single dots the spin relaxation rate scales approximately with the seventh power of the magnetic field, in line with a recent experiment. In double dots the relaxation rate is much more sensitive to the dot spectrum structure, as it is often dominated by a spin hot spot. The anisotropy of the spin-orbit interactions gives rise to easy passages, special directions of the magnetic field for which the relaxation is strongly suppressed. Quantitatively, the spin relaxation rates in Si are typically 2 orders of magnitude smaller than in GaAs due to the absence of the piezoelectric phonon potential and generally weaker spinorbit interactions.

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“…[1][2][3][4][5][6] The experimental control over the electron spin in quantum dots has seen enormous progress, with lateral gated GaAs structures demonstrating the state of the art.…”

mentioning

confidence: 99%

Theory of single electron spin relaxation in Si/SiGe lateral coupled quantum dots

2011

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“…Previous works have proposed to detect the entanglement present in the spin degrees of freedom of a Cooper pair via correlation measurements. 29,[34][35][36][37][38][39][40][41][42][43] The Franson interferometer we consider here, on the other hand, is suited for probing the coherence properties of the spatial degrees of freedom of the emitted Cooper pair. By looking at the interference fringes in the coincidence counts at the output ports, varying the relevant parameters of the Franson interferometer, we can measure the pair correlation length of the emitted Cooper pair, which is proportional to Pippard's length characterizing the extension of the Cooper pair in the superconducting source, as well as the momentum of the center-of-mass motion of the emitted Cooper pair, i.e., the de Broglie wavelength of the emitted Cooper pair as a single object.…”

Section: 33mentioning

confidence: 99%

Probing Cooper pairs with Franson interferometry

Giovannetti

Yuasa

2012

Phys. Rev. B

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A setup based on the Franson optical interferometer is analyzed, which allows us to detect the coherence properties of Cooper pairs emerging via tunneling from a superconductor in contact with two one-dimensional channels. By tuning the system parameters we show that both the internal coherence of the emitted Cooper pairs, which is proportional to Pippard's length, and the de Broglie wavelength of their center-of-mass motion can be measured via current-current correlation measurements.

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“…Electron entanglement can be produced either by interacting mechanisms [3][4][5][6][7][8] (e.g., exchange coupling and superconducting pairing) or noninteracting ones [9][10][11][12][13][14][15] (based on exchange correlations in scattering processes from external potentials). Electronic devices such as quantum dots and quantum wires have been proposed to produce entanglement of electrons without interactions [16,17]. The efficiency of these noninteracting entanglers depends on the scattering of electrons traveling through the system.…”

Section: Introductionmentioning

confidence: 99%

Orbital entanglement and electron localization in quantum wires

et al. 2014

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We study the signatures of disorder in the production of orbital electron entanglement in quantum wires. Disordered entanglers suffer the effects of localization of the electron wave function and random fluctuations in entanglement production. This manifests in the statistics of the concurrence, a measure of the produced two-qubit entanglement. We calculate the concurrence distribution as a function of the disorder strength within a randommatrix approach. We also identify significant constraints on the entanglement production as a consequence of the breaking/preservation of time-reversal symmetry. Additionally, our theoretical results are independently supported by simulations of disordered quantum wires based on a tight-binding model.

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Spin-entangled electrons in solid-state systems

Abstract: Entanglement is one of the fundamental resources for quantum information processing. This is an overview on theoretical work focused on the physics of the detection, production, and transport of entangled electron spins in solid-state structures.

Cited by 36 publications

References 112 publications

Theory of single electron spin relaxation in Si/SiGe lateral coupled quantum dots

Theory of single electron spin relaxation in Si/SiGe lateral coupled quantum dots

Probing Cooper pairs with Franson interferometry

Orbital entanglement and electron localization in quantum wires

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