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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

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

Despite an apparent progress in implementing individual solid-state qubits, there have been no experimental reports so far on multi-bit gates required for building a real quantum computer. Here we report a new circuit comprising two coupled…

Mesoscale and Nanoscale Physics · Physics 2010-04-20 Yu. A. Pashkin , T. Yamamoto , O. Astafiev , Y. Nakamura , D. V. Averin , J. S. Tsai

We study theoretically the quantum dynamics of two interacting electrons in the symmetric double-dot structure under the influence of the bichromatic resonant pulse. The state vector evolution is studied for two different pulse designs. It…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Alexander V. Tsukanov

We propose a tunable nonlinear interaction for the implementation of quantum logic operations on pairs of superconducting resonators, where the two-resonator interaction is mediated by a transmon quantum bit (qubit). This interaction is…

Quantum Physics · Physics 2018-07-12 Frederick W. Strauch , Matteo Mariantoni

The double quantum dot device benefits from the advantages of both the spin and charge qubits, while offering ways to mitigate their drawbacks. Careful gate voltage modulation can grant greater spinlike or chargelike dynamics to the device,…

Mesoscale and Nanoscale Physics · Physics 2022-08-12 Vincent Reiher , Yves Bérubé-Lauzière

We analyze optimal schemes and also propose some practical schemes for the nonlocal conversion from two shared Bell pairs to four-qubit entangled states in optical quantum networks. In the analysis, we consider two-qubit operations as…

Quantum Physics · Physics 2018-05-02 Yuki Takeuchi , Nobuyuki Imoto , Toshiyuki Tashima

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

Fast operations, an easily tunable Hamiltonian, and a straightforward two-qubit interaction make charge qubits a useful tool for benchmarking device performance and exploring two-qubit dynamics. Here, we tune a linear chain of four Si/SiGe…

We present a feasible scheme for performing an optically controlled phase gate between two conduction electron spin qubits in adjacent self assembled quantum dots. Interaction between the dots is mediated by the tunneling of the valence…

Quantum Physics · Physics 2015-05-20 Li-Bo Chen , L. J. Sham , Edo Waks

Based on an idea that spatial separation of charge states can enhance quantum coherence, we propose a scheme for quantum computation with quantum bit (qubit) constructed from two coupled quantum dots. Quantum information is stored in…

Quantum Physics · Physics 2009-11-07 Xin-Qi Li , YiJing Yan

Quantum computers comprise elementary logic gates that initialize, control and measure delicate quantum states. One of the most important gates is the controlled-NOT, which is widely used to prepare two-qubit entangled states. The…

Quantum Physics · Physics 2024-01-04 Robert J. Chapman , Samuel Häusler , Giovanni Finco , Fabian Kaufmann , Rachel Grange

Tunnel-coupled pairs of optically active quantum dots - quantum dot molecules (QDMs) - offer the possibility to combine excellent optical properties such as strong light-matter coupling with two-spin singlet-triplet ($S-T_0$) qubits having…

A two-qubit quantum gate is realized using electronic excited states in a single ion with an energy separation on the order of a terahertz times the Planck constant as a qubit. Two phase locked lasers are used to excite a stimulated Raman…

Quantum Physics · Physics 2015-05-18 K. Toyoda , S. Haze , R. Yamazaki , S. Urabe

This work presents a step furthering a new perspective of proactive control of the spin-exciton dynamics in the quantum limit. Laser manipulation of spin-polarized optical excitations in a semiconductor nanodot is used to control the spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Pochung Chen , C. Piermarocchi , L. J. Sham

We analyzed theoretically localized charge relaxation in a double quantum dot (QD) system coupled with continuous spectrum states in the presence of localized electrons Coulomb interaction in a single QD. We have found that for a wide range…

Mesoscale and Nanoscale Physics · Physics 2012-07-13 V. N. Mantsevich , N. S. Maslova , P. I. Arseyev

In this work, we study strategies for the optical control, within the dipole approximation, of a qubit encoded in the three-electron states of a triple quantum dot. The system is described by effective confining potentials, and its…

Mesoscale and Nanoscale Physics · Physics 2019-01-30 Diego S. Acosta Coden , Sergio S. Gomez , Rodolfo H. Romero , Omar Osenda , Alejandro Ferrón

One of the greatest difficulties in the applications of single photon polarization states as qubits is the realization of controlled interactions between two photons. Recently, it has been shown that such interactions can be realized using…

Quantum Physics · Physics 2007-05-23 Holger F. Hofmann , Shigeki Takeuchi

We propose a scheme for realizing quantum controlled phase gates with two nonidentical quantum dots trapped in two coupled photonic crystal cavities and driven by classical laser fields under the condition of non-small hopping limit. During…

Quantum Physics · Physics 2015-03-19 Jian-Qi Zhang , Ya-Fei Yu , Zhi-Ming Zhang

We present a set of concrete and realistic ideas for the implementation of a small-scale quantum computer using electron spins in lateral GaAs/AlGaAs quantum dots. Initialization is based on leads in the quantum Hall regime with tunable…