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Spin qubits and superconducting qubits are among the promising candidates for a solid state quantum computer. For the implementation of a hybrid architecture which can profit from the advantages of either world, a coherent long-distance…

Silicon quantum dot spin qubits provide a promising platform for large-scale quantum computation because of their compatibility with conventional CMOS manufacturing and the long coherence times accessible using $^{28}$Si enriched material.…

We consider a double-quantum-dot (DQD) qubit which contains six electrons instead of the usual one or two. In this spin qubit, quantum information is encoded in a low-lying singlet-triplet space much as in the case of a two-electron DQD…

Mesoscale and Nanoscale Physics · Physics 2013-11-21 Erik Nielsen , Edwin Barnes , J. P. Kestner , S. Das Sarma

We introduce a scheme to perform quantum-information processing that is based on a hybrid spin-photon qubit encoding. The proposed qubits consist of spin-ensembles coherently coupled to microwave photons in coplanar waveguide resonators.…

Quantum Physics · Physics 2013-09-19 S. Carretta , A. Chiesa , F. Troiani , D. Gerace , G. Amoretti , P. Santini

The effects of a nearby two-level charge fluctuator on a double-dot two-spin qubit are studied theoretically. Assuming no direct tunneling between the charge fluctuator and the qubit quantum dots, the Coulomb couplings between the qubit…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Guy Ramon , Xuedong Hu

We propose and analyse a scheme for performing a long-range entangling gate for qubits encoded in electron spins trapped in semiconductor quantum dots. Our coupling makes use of an electrostatic interaction between the state-dependent…

Mesoscale and Nanoscale Physics · Physics 2017-09-07 Samuel J. Elman , Stephen D. Bartlett , Andrew C. Doherty

Coherent two-level systems, or qubits, based on electron spins in GaAs quantum dots are strongly coupled to the nuclear spins of the host lattice via the hyperfine interaction. Realizing nuclear spin control would likely improve electron…

Mesoscale and Nanoscale Physics · Physics 2010-06-15 D. J. Reilly , J. M. Taylor , J. R. Petta , C. M. Marcus , M. P. Hanson , A. C. Gossard

A new approach to single-qubit operations using exchange interactions of single electrons in gate-defined quantum dots has recently been demonstrated: the resonant exchange qubit. We show that two-qubit operations, specifically the CPHASE…

Mesoscale and Nanoscale Physics · Physics 2013-08-09 Andrew C. Doherty , Matthew P. Wardrop

The interaction between two quantum bits enables entanglement, the two-particle correlations that are at the heart of quantum information science. In semiconductor quantum dots much work has focused on demonstrating single spin qubit…

Mesoscale and Nanoscale Physics · Physics 2011-03-14 Danny Kim , Samuel G. Carter , Alex Greilich , Allan Bracker , Daniel Gammon

Spin-orbit coupling is relatively weak for electrons in bulk silicon, but enhanced interactions are reported in nanostructures such as the quantum dots used for spin qubits. These interactions have been attributed to various dissimilar…

Taking the excess electron spin in a unit cell of semiconductor multiple quantum-dot structure as a qubit, we can implement scalable quantum computation without resorting to spin-spin interactions. The technique of single electron…

Quantum Physics · Physics 2007-05-23 Wei-Min Zhang , Yin-Zhong Wu , Chopin Soo

We present a modulated microwave approach for quantum computing with qubits comprising three spins in a triple quantum dot. This approach includes single- and two-qubit gates that are protected against low-frequency electrical noise, due to…

Mesoscale and Nanoscale Physics · Physics 2013-08-09 J. M. Taylor , V. Srinivasa , J. Medford

Given the effectiveness of semiconductor devices for classical computation one is naturally led to consider semiconductor systems for solid state quantum information processing. Semiconductors are particularly suitable where local control…

Materials Science · Physics 2009-11-11 A. M. Tyryshkin , J. J. L. Morton , S. C. Benjamin , A. Ardavan , G. A. D. Briggs , J. W. Ager , S. A. Lyon

The engineering of quantum devices has reached the stage where we now have small scale quantum processors containing multiple interacting qubits within them. Simple quantum circuits have been demonstrated and scaling up to larger numbers is…

Charge noise has been one of the main issues in realizing high fidelity two-qubit quantum gates in semiconductor based qubits. Here, we study the influence of quasistatic noise in quantum dot detuning on the controlled phase gate for spin…

Mesoscale and Nanoscale Physics · Physics 2023-12-21 Yinan Fang

The performance of multi-electron spin qubits is examined by comparing exchange oscillations in coupled single-electron and multi-electron quantum dots in the same device. Fast (> 1 GHz) exchange oscillations with a quality factor Q > 15…

Mesoscale and Nanoscale Physics · Physics 2014-01-21 A. P. Higginbotham , F. Kuemmeth , M. P. Hanson , A. C. Gossard , C. M. Marcus

Implementation of quantum information processing faces the contradicting requirements of combining excellent isolation to avoid decoherence with the ability to control coherent interactions in a many-body quantum system. For example, spin…

Quantum Physics · Physics 2015-05-13 P. Rabl , S. J. Kolkowitz , F. H. Koppens , J. G. E. Harris , P. Zoller , M. D. Lukin

The scalability and power of quantum computing architectures depend critically on high-fidelity operations and robust and flexible qubit connectivity. In this respect, mobile qubits are particularly attractive as they enable dynamic and…

We show that two electrons confined in a square semiconductor quantum dot have two isolated low-lying energy eigenstates, which have the potential to form the basis of scalable computing elements (qubits). Initialisation, one-qubit and…

Quantum Physics · Physics 2009-11-07 J. H. Jefferson , M. Fearn , D. L. J. Tipton , T. P. Spiller

A single hole spin in a semiconductor quantum dot has emerged as a quantum bit that is potentially superior to an electron spin. A key feature of holes is that they have a greatly reduced hyperfine interaction with nuclear spins, which is…

Mesoscale and Nanoscale Physics · Physics 2011-11-14 Alex Greilich , Samuel G. Carter , Danny Kim , Allan S. Bracker , Daniel Gammon