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We propose to implement quantum computing based on electronic spin qubits by controlling the propagation of the electron wave packets through the helical edge states of quantum spin Hall systems (QSHs). Specfically, two non-commutative…

Mesoscale and Nanoscale Physics · Physics 2014-04-04 Wei Chen , Zheng-Yuan Xue , Z. D. Wang , R. Shen , D. Y. Xing

Pulsed magnetic resonance is a wide-reaching technology allowing the quantum state of electronic and nuclear spins to be controlled on the timescale of nanoseconds and microseconds respectively. The time required to flip either dilute…

The ability to control the quantum state of a single electron spin in a quantum dot is at the heart of recent developments towards a scalable spin-based quantum computer. In combination with the recently demonstrated exchange gate between…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 F. H. L. Koppens , C. Buizert , K. J. Tielrooij , I. T. Vink , K. C. Nowack , T. Meunier , L. P. Kouwenhoven , L. M. K. Vandersypen

The universal quantum computer is a device capable of simulating any physical system and represents a major goal for the field of quantum information science. Algorithms performed on such a device are predicted to offer significant gains…

Quantum Physics · Physics 2010-01-04 D. Hanneke , J. P. Home , J. D. Jost , J. M. Amini , D. Leibfried , D. J. Wineland

We apply quantum control techniques to control a large spin chain by only acting on two qubits at one of its ends, thereby implementing universal quantum computation by a combination of quantum gates on the latter and swap operations across…

We present a universal set of quantum gate operations based on exchange-only spin qubits in a double quantum dot, where each qubit is obtained by three electrons in the (2,1) filling. Gate operations are addressed by modulating…

Quantum Physics · Physics 2018-09-05 Marco De Michielis , Elena Ferraro , Marco Fanciulli , Enrico Prati

In this article, we study control of electron-nuclear spin dynamics at magnetic field strengths where the Larmor frequency of the nucleus is comparable to the hyperfine coupling strength. The quantization axis for the nuclear spin differs…

Quantum Physics · Physics 2009-11-13 Navin Khaneja

For spin-based quantum computation in semiconductors, dephasing of electron spins by a fluctuating background of nuclear spins is a main obstacle. Here we show that this nuclear background can be precisely controlled in generic quantum dots…

Mesoscale and Nanoscale Physics · Physics 2019-06-19 Sergej Markmann , Christian Reichl , Werner Wegscheider , Gian Salis

We propose a novel scheme to efficiently polarize and manipulate the electron spin in a quantum dot. This scheme is based on the spin-orbit interaction and it possesses following advantages: (1) The direction and the strength of the spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Qing-feng Sun , X. C. Xie

The universal quantum computation is obtained when there exists asymmetric anisotropic exchange between electron spins in coupled semiconductor quantum dots. The asymmetric Heisenberg model can be transformed into the isotropic model…

Quantum Physics · Physics 2009-11-13 Xiang Hao , Shiqun Zhu

Universal quantum computation requires the implementation of arbitrary control operations on the quantum register. In most cases, this is achieved by external control fields acting selectively on each qubit to drive single-qubit operations.…

Quantum Physics · Physics 2015-06-19 Jingfu Zhang , Daniel Burgarth , Raymond Laflamme , Dieter Suter

We investigate a two-electron double quantum dot with both spin and valley degrees of freedom as they occur in graphene, carbon nanotubes, or silicon, and regard the 16-dimensional space with one electron per dot as a four-qubit logic…

Mesoscale and Nanoscale Physics · Physics 2016-01-20 Niklas Rohling , Guido Burkard

We demonstrate high-fidelity reversible transfer of quantum information from the polarisation of photons into the spin-state of an electron-hole pair in a semiconductor quantum dot. Moreover, spins are electrically manipulated on a…

The representation of information within the spins of electrons and nuclei has been powerful in the ongoing development of quantum computers. Although nuclear spins are advantageous as quantum bits (qubits) due to their long coherence…

Large-scale quantum computers must be built upon quantum bits that are both highly coherent and locally controllable. We demonstrate the quantum control of the electron and the nuclear spin of a single 31P atom in silicon, using a…

Most quantum computer realizations require the ability to apply local fields and tune the couplings between qubits, in order to realize single bit and two bit gates which are necessary for universal quantum computation. We present a scheme…

Quantum Physics · Physics 2009-11-07 Xingxiang Zhou , Zheng-Wei Zhou , Guang-Can Guo , Marc J. Feldman

Once called a "classically non-describable two-valuedness" by Pauli , the electron spin is a natural resource for long-lived quantum information since it is mostly impervious to electric fluctuations and can be replicated in large arrays…

We consider a double quantum dot system with two embedded and non-aligned spin impurities to manipulate the magnitude and polarization of the electron spin density. The device is attached to semi-infinite one-dimensional leads which are…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Gianluca Stefanucci , Enrico Perfetto , Michele Cini

Exchange-coupled singlet-triplet spin qubits in two gate-defined double quantum dots are considered theoretically. Using charge density operators to describe the double-dot orbital states, we calculate the Coulomb couplings between the…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Guy Ramon

We propose to use the spin-orbit interaction as a means to control electron spins in quantum dots, enabling both single qubit and two qubit operations. Very fast single qubit operations may be achieved by temporarily displacing the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Christian Flindt , Anders S. Sorensen , Karsten Flensberg