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We investigate charge dynamics in a two-electron double quantum dot. The quantum dot is manipulated by using a time-dependent external voltage that induces charge oscillations between the dots. We study the dependence of the charge dynamics…

Mesoscale and Nanoscale Physics · Physics 2010-12-23 Jani Särkkä , Ari Harju

Quantum dots are artificial atoms used for a multitude of purposes. Charge defects are commonly present and can significantly perturb the designed energy spectrum and purpose of the dots. Voltage controlled exchange energy in silicon double…

Mesoscale and Nanoscale Physics · Physics 2012-03-21 Rajib Rahman , Erik Nielsen , Richard P. Muller , Malcolm S. Carroll

We describe an electrodynamic mechanism for coherent, quantum mechanical coupling between spacially separated quantum dots on a microchip. The technique is based on capacitive interactions between the electron charge and a superconducting…

Quantum Physics · Physics 2009-11-10 L. I. Childress , A. S. Sorensen , M. D. Lukin

We study the two-qubit controlled-not gate operating on qubits encoded in the spin state of a pair of electrons in a double quantum dot. We assume that the electrons can tunnel between the two quantum dots encoding a single qubit, while…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Dimitrije Stepanenko , Guido Burkard

We propose an implementation of the two-qubit gate in a quantum dot spin qubit system which is immune to charge noise problems. Our proposed implementation, if it could be realized in a physical system, would have the advantage of being…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 J. P. Kestner , S. Das Sarma

We consider the full driven quantum dynamics of a qubit realized as spin of electron in a one-dimensional double quantum dot with spin-orbit coupling. The driving perturbation is taken in the form of a single half-period pulse of electric…

Mesoscale and Nanoscale Physics · Physics 2010-09-28 D. V. Khomitsky , E. Ya. Sherman

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

We study the dynamics of a single electron spin in a double quantum dot (DQD) and its readout via a quantum point contact (QPC). We model the system microscopically and derive rate equations for the reduced electron density matrix of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Jian-Ping Zhang , Shi-Hua Ouyang , Chi-Hang Lam , J. Q. You

Two-qubit quantum gates play an essential role in quantum computing, whose operation critically depends on the entanglement between two qubits. Resonantly driven controlled-NOT (CNOT) gates based on silicon double quantum dots (DQDs) are…

Mesoscale and Nanoscale Physics · Physics 2018-09-11 Tong Wu , Jing Guo

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

We report coherent operation of a singlet-triplet qubit controlled by the arrangement of two electrons in an adjacent double quantum dot. The system we investigate consists of two pairs of capacitively coupled double quantum dots fabricated…

Mesoscale and Nanoscale Physics · Physics 2011-07-20 I. van Weperen , B. D. Armstrong , E. A. Laird , J. Medford , C. M. Marcus , M. P. Hanson , A. C. Gossard

Quantum coherence in solid-state systems has been demonstrated in superconducting circuits and in semiconductor quantum dots. This has paved the way to investigate solid-state systems for quantum information processing with the potential…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 T. Frey , P. J. Leek , M. Beck , A. Blais , T. Ihn , K. Ensslin , A. Wallraff

We study the occupation of two electrostatically-coupled single-level quantum dots with spinless electrons as a function of gate voltage. While the total occupation of the double-dot system varies monotonically with gate voltage, we predict…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Jürgen König , Yuval Gefen

The spin-sensitive charge oscillation, controlled by an external magnetic field, was recently proposed as a mechanism of transformations of qubits, defined as two-electron spin-charge Wannier molecules in a square quantum dot. The paper…

Mesoscale and Nanoscale Physics · Physics 2020-07-30 Ambroz Kregar , Anton Ramsak

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 experimentally demonstrate a tunable hybrid qubit in a five-electron GaAs double quantum dot. The qubit is encoded in the (1,4) charge regime of the double dot and can be manipulated completely electrically. More importantly, dot…

Mesoscale and Nanoscale Physics · Physics 2016-03-02 Gang Cao , Hai-Ou Li , Guo-Dong Yu , Bao-Chuan Wang , Bao-Bao Chen , Xiang-Xiang Song , Ming Xiao , Guang-Can Guo , Hong-Wen Jiang , Xuedong Hu , Guo-Ping Guo

Coupled quantum dots are potential candidates for qubit systems in quantum computing. We use a non-invasive voltage probe to study the evolution of a coupled dot system from a situation where the dots are coupled to the leads to a situation…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. W. Rushforth , C. G. Smith , M. D. Godfrey , H. E. Beere , D. A. Ritchie , M. Pepper

Single-shot measurement of the charge arrangement and spin state of a double quantum dot are reported, with measurement times down to ~ 100 ns. Sensing uses radio-frequency reflectometry of a proximal quantum dot in the Coulomb blockade…

Mesoscale and Nanoscale Physics · Physics 2010-04-27 C. Barthel , M. Kjaergaard , J. Medford , M. Stopa , C. M. Marcus , M. P. Hanson , A. C. Gossard

A semiconductor quintuple quantum dot with two charge sensors and an additional contact to the center dot from an electron reservoir is fabricated to demonstrate the concept of scalable architecture. This design enables formation of the…

The Coulomb interactions between electrons play important roles in coupling multiple qubits in various quantum systems. Here we demonstrate controlled quantum operations of three electron charge qubits based on three capacitively coupled…

Mesoscale and Nanoscale Physics · Physics 2018-02-21 Hai-Ou Li , Gang Cao , Guo-Dong Yu , Ming Xiao , Guang-Can Guo , Hong-Wen Jiang , Guo-Ping Guo