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We present a new experimental protocol for performing universal gates in a register of superconducting qubits coupled by fixed on-chip linear reactances. The qubits have fixed, detuned Larmor frequencies and can remain, during the entire…

Quantum Physics · Physics 2009-11-10 Chad Rigetti , Michel Devoret

Manipulation of single spins is essential for spin-based quantum information processing. Electrical control instead of magnetic control is particularly appealing for this purpose, since electric fields are easy to generate locally on-chip.…

Mesoscale and Nanoscale Physics · Physics 2008-03-10 K. C. Nowack , F. H. L. Koppens , Yu. V. Nazarov , L. M. K. Vandersypen

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

We propose an effective set of elementary quantum gates which provide an encoded universality and demonstrate the physical feasibility of these gates for the solid-state quantum computer based on the multi-atomic systems in the QED cavity.…

Quantum Physics · Physics 2011-09-05 Farid Ablayev , Sergey Andrianov , Sergey Moiseev , Alexander Vasiliev

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

The manipulation of single spins in double quantum dots by making use of the exchange interaction and a highly inhomogeneous magnetic field was discussed in [W. A. Coish and D. Loss, Phys. Rev. B 75, 161302 (2007)]. However, such large…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 Stefano Chesi , Ying-Dan Wang , Jun Yoneda , Tomohiro Otsuka , Seigo Tarucha , Daniel Loss

We discuss a possibility of implementing a universal quantum XOR gate, by using two coupled quantum dots subjected to external magnetic fields that are parallel and slightly different. We consider this system in two different field…

Quantum Physics · Physics 2008-05-17 M. C. Baldiotti , D. M. Gitman

Quantum computation requires qubits that can be coupled and realized in a scalable manner, together with universal and high-fidelity one- and two-qubit logic gates \cite{DiVincenzo2000, Loss1998}. Strong effort across several fields have…

We propose a fast optically induced two-qubit \textsc{c-phase} gate between two resident spins in a pair of coupled quantum dots. An excited bound state which extends over the two dots provides an effective electron-electron exchange…

Mesoscale and Nanoscale Physics · Physics 2008-09-15 Sophia E. Economou , T. L. Reinecke

We show that an effective two-qubit gate can be obtained from the free evolution of three spins in a chain with nearest neighbor XY coupling, without local manipulations. This gate acts on the two remote spins and leaves the mediating spin…

Quantum Physics · Physics 2007-05-23 Man-Hong Yung , Debbie W. Leung , Sougato Bose

We propose a mechanism of a long-range coherent interaction between two singlet-triplet qubits dipolarly coupled to a dogbone-shaped ferromagnet. An effective qubit-qubit interaction Hamiltonian is derived and the coupling strength is…

Mesoscale and Nanoscale Physics · Physics 2013-05-14 Luka Trifunovic , Fabio L. Pedrocchi , Daniel Loss

We present an approach for entangling electron spin qubits localized on spatially separated impurity atoms or quantum dots via a multi-electron, two-level quantum dot. The effective exchange interaction mediated by the dot can be understood…

Mesoscale and Nanoscale Physics · Physics 2015-06-10 V. Srinivasa , H. Xu , J. M. Taylor

It has been widely assumed that one-qubit gates in spin-based quantum computers suffer from severe technical difficulties. We show that one-qubit gates can in fact be generated using only modest and presently feasible technological…

Quantum Physics · Physics 2007-05-23 Lian-Ao Wu , Daniel A. Lidar , Mark Friesen

We report individual confinement and two-axis qubit operations of two electron spin qubits in GaAs gate-defined sextuple quantum dot array with integrated micro-magnet. As a first step toward multiple qubit operations, we demonstrate…

Mesoscale and Nanoscale Physics · Physics 2021-02-03 Wonjin Jang , Min-Kyun Cho , Jehyun Kim , Hwanchul Chung , Vladimir Umansky , Dohun Kim

Shuttling spin qubits in systems with large spin-orbit interaction (SOI) can cause errors during motion. However, in this work, we demonstrate that SOI can be harnessed to implement an arbitrary high-fidelity two-qubit (2Q) gate. We…

Mesoscale and Nanoscale Physics · Physics 2025-08-13 D. Fernández-Fernández , Y. Matsumoto , L. M. K. Vandersypen , G. Platero , S. Bosco

Universal set of quantum gates are realized from the conduction-band electron spin qubits of quantum dots embedded in a microcavity via two-channel Raman interaction. All of the gate operations are independent of the cavity mode states,…

Quantum Physics · Physics 2007-12-20 Ping Dong , Ming Yang , Zhuo-Liang Cao

We demonstrate that conditional as well as unconditional basic operations which are prerequisite for universal quantum gates can be performed with almost 100% fidelity within a strongly interacting two-electron quantum ring. Both sets of…

Mesoscale and Nanoscale Physics · Physics 2016-08-14 Lene Sælen , Erik Waltersson , J. P. Hansen , Eva Lindroth

We analyse a simple exchange-based two-qubit gate for singlet-triplet qubits in gate-defined semiconductor quantum dots that can be implemented in a single exchange pulse. Excitations from the logical subspace are suppressed by a magnetic…

Mesoscale and Nanoscale Physics · Physics 2014-07-30 Matthew P. Wardrop , Andrew C. Doherty

We propose a scheme for the implementation of quantum gates which is based on the qubit encoding in antiferromagnetic molecular rings. We show that a proper engineering of the intercluster link would result in an effective coupling that…

Other Condensed Matter · Physics 2009-11-10 F. Troiani , M. Affronte , S. Carretta , P. Santini , G. Amoretti

We propose a method of compiling that permits to identify quantum circuits able to simulate arbitrary $n$-qubit unitary operations via the adjustment of angles in single-qubit gates therein. The method of compiling itself extends older…

Quantum Physics · Physics 2021-01-06 Rahul P. Singh , A. Mandilara