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Related papers: Singlet-triplet decoherence due to nuclear spins i…

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We investigate the dynamic nuclear polarization process by frequently injecting polarized electron spins into a quantum dot. Due to the suppression of the direct dipolar and indirect electron-mediated nuclear spin interactions, by the…

Mesoscale and Nanoscale Physics · Physics 2016-07-26 Na Wu , Wenkui Ding , Anqi Shi , Wenxian Zhang

We calculate the pure dephasing time of three-electron exchange-only qubits due to interaction with the nuclear hyperfine field. Within the $S=S_z=1/2$ spin subspace, we derive formulas for the dephasing time in the $(1,1,1)$ charge region…

Mesoscale and Nanoscale Physics · Physics 2017-12-20 Csaba G. Péterfalvi , Guido Burkard

We investigate decoherence due to pure dephasing of a localized spin qubit interacting with a nuclear spin bath. Although in the limit of a very large magnetic field the only decoherence mechanism is spectral diffusion due to dipolar…

Mesoscale and Nanoscale Physics · Physics 2009-06-18 L. Cywinski , W. M. Witzel , S. Das Sarma

We study the time evolution of entanglement of two spins in anisotropically coupled quantum dot interacting with the unpolarized nuclear spins environment. We assume that the exchange coupling strength in the z-direction $J_z$ is different…

Mesoscale and Nanoscale Physics · Physics 2012-01-04 Gehad Sadiek , Zhen Huang , Omar Aldossary , Sabre Kais

We investigate in detail, using both analytical and numerical tools, the decoherence of electron spins in quantum dots (QDs) coupled to a bath of nuclear spins in magnetic fields or with various initial bath polarizations, focusing on the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Wenxian Zhang , V. V. Dobrovitski , K. A. Al-Hassanieh , E. Dagotto , B. N. Harmon

The spin fluctuations of electron and hole doped self-assembled quantum dot ensembles are measured optically in the low-intensity limit of a probe laser in absence and presence of longitudinal or transverse static magnetic fields. The…

Mesoscale and Nanoscale Physics · Physics 2016-06-01 P. Glasenapp , D. S. Smirnov , A. Greilich , J. Hackmann , M. M. Glazov , F. B. Anders , M. Bayer

We investigate pure dephasing decoherence (free induction decay and spin echo) of a spin qubit interacting with a nuclear spin bath. While for infinite magnetic field B the only decoherence mechanism is spectral diffusion due to dipolar…

Mesoscale and Nanoscale Physics · Physics 2009-02-03 L. Cywinski , W. M. Witzel , S. Das Sarma

The spin interaction between an electron and nuclei was investigated optically in a single self-assembled InAlAs quantum dot (QD). In spin dynamics, the correlation time of the coupled electron-nuclear spin system and the electron spin…

Materials Science · Physics 2011-08-29 R. Kaji , H. Sasakura , S. Adachi , S. Muto

The electron-nuclei (hyperfine) interaction is central to spin qubits in solid state systems. It can be a severe decoherence source but also allows dynamic access to the nuclear spin states. We study a double quantum dot exposed to an…

Mesoscale and Nanoscale Physics · Physics 2013-06-13 Gunnar Petersen , Eric A. Hoffmann , Dieter Schuh , Werner Wegscheider , Geza Giedke , Stefan Ludwig

A successful and promising device for the physical implementation of electron spin-valley based qubits is the Transition Metal Dichalcogenide monolayer (TMD-ML) semiconductor quantum dot. The electron spin in TMD-ML semiconductor quantum…

Mesoscale and Nanoscale Physics · Physics 2021-11-24 Mehdi Arfaoui , Sihem Jaziri

The time evolution of spin states of two electrons interacting with a nuclear spin bath in a quantum dot system is studied. The hyperfine interaction between the electrons and the nuclear spins is modeled by an isotropic Heisenberg…

Quantum Physics · Physics 2013-07-09 D. D. Bhaktavatsala Rao , V. Ravishankar , V. Subrahmanyam

Recent experiments on semiconductor quantum dots have demonstrated the ability to utilize a large quantum dot to mediate superexchange interactions and generate entanglement between distant spins. This opens up a possible mechanism for…

Mesoscale and Nanoscale Physics · Physics 2020-07-29 Kuangyin Deng , Edwin Barnes

An inhomogeneous magnetic exchange field at a superconductor/ferromagnet interface converts spin-singlet Cooper pairs to a spin-aligned (i.e. spin-polarized) triplet state. Although the decay envelope of such triplet pairs within…

Nuclear spins are an important source of dephasing for electron spin qubits in GaAs quantum dots. Most studies of their dynamics have focused on the relatively slow longitudinal polarization. We show, based on a semiclassical model and…

Mesoscale and Nanoscale Physics · Physics 2015-09-30 Christian Dickel , Sandra Foletti , Vladimir Umansky , Hendrik Bluhm

We study exchange coupling in Si double quantum dots, which have been proposed as suitable candidates for spin qubits due to their long spin coherence times. We discuss in detail two alternative schemes which have been proposed for…

Mesoscale and Nanoscale Physics · Physics 2010-02-12 Qiuzi Li , Lukasz Cywinski , Dimitrie Culcer , Xuedong Hu , S. Das Sarma

Coupled pairs of nuclear spins-1/2 support one singlet state and three triplet states. Transitions between the singlet state and one of the triplet states may be driven by an oscillating low-frequency magnetic field, in the presence of…

Quantum Physics · Physics 2021-10-27 Laurynas Dagys , Christian Bengs , Malcolm H. Levitt

We report a successful measurement of the magnetic field-induced spin singlet-triplet transition in silicon-based coupled dot systems. Our specific experimental scheme incorporates a lateral gate-controlled Coulomb-blockaded structure in Si…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 S. D. Lee , S. J. Kim , J. S. Kang , Y. B. Cho , J. B. Choi , Sooa Park , S. -R. Eric Yang , S. J. Lee , T. H. Zyung

We theoretically investigate quantum spin transfer from spin-correlated conduction-electron pairs to localized spins in a ferromagnet, given that electrons are correlated intrinsically. We show that even spin-singlet pairs and triplet pairs…

Mesoscale and Nanoscale Physics · Physics 2026-01-09 Seongmun Hwang , Jung Hyun Oh , Paul M. Haney , Mark D. Stiles , Kyung-Jin Lee

Conventional phonon-electron interaction induces either triplet or one of two (degenerate) singlet pairing states in time reversal and inversion invariant 3D Dirac semi - metal. Investigation of the order parameters and energies of these…

Superconductivity · Physics 2015-06-22 Baruch Rosenstein , B. Ya. Shapiro , Dingping Li , I. Shapiro

A pair of coupled dots with one electron in each dot can provide improvements in spin coherence, particularly at an electrical bias called the sweet spot, but few measurements have been performed on self-assembled dots in this regime. Here,…

Mesoscale and Nanoscale Physics · Physics 2022-02-17 Kha X. Tran , Allan S. Bracker , Michael K. Yates , Joel Q. Grim , Samuel G. Carter