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The dynamics of charge qubit in double quantum dot coupled to phonons is investigated theoretically. The static bias is considered. By means of the perturbation approach based on unitary transformations, the dynamical tunneling current is…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Xiufeng Cao , Hang Zheng

An approach which allows to include the corrections from non-orthogonality of electron states in contacts and quantum dots is developed. Comparison of the energy levels and charge distributions of electrons in 1D quantum dot (QD) in…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 J. Fransson , O. Eriksson , B. Johansson , I. Sandalov

A quantum point contact (QPC) patterned on a two-dimensional electron gas is investigated with a scanning gate setup operated at a temperature of 300 mK. The conductance of the point contact is recorded while the local potential is modified…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 A. Pioda , S. Kicin , D. Brunner , T. Ihn , M. Sigrist , K. Ensslin , M. Reinwald , W. Wegscheider

The quantum phase transition (QPT) of the one-dimensional (1D) quantum compass model in a transverse magnetic field is studied in this paper. An exact solution is obtained by using an extended Jordan and Wigner transformation to the…

Quantum Physics · Physics 2009-11-21 Ke-Wei Sun , Qing-Hu Chen

We investigate experimentally and theoretically few-particle effects in the optical spectra of single quantum dots (QDs). Photo-depletion of the QD together with the slow hopping transport of impurity-bound electrons back to the QD are…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Arno Hartmann , Yann Ducommun , Eli Kapon , Ulrich Hohenester , Elisa Molinari

Solid state quantum bits are a promising candidate for the realization of a scalable quantum computer, however, they are usually strongly limited by decoherence. We consider a double quantum dot charge qubit, whose basis states are defined…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 Udo Hartmann , Frank K. Wilhelm

We report high-bandwidth charge sensing measurements using a GaAs quantum point contact embedded in a radio frequency impedance matching circuit (rf-QPC). With the rf-QPC biased near pinch-off where it is most sensitive to charge, we…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 D. J. Reilly , C. M. Marcus , M. P. Hanson , A. C. Gossard

We report experimental results on a quantum point contact (QPC) device formed in a wide AlAs quantum well where the two-dimensional electrons occupy two in-plane valleys with elliptical Fermi contours. To probe the closely-spaced,…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 O. Gunawan , B. Habib , E. P. De Poortere , M. Shayegan

We propose to continuously monitor a charge qubit by utilizing a T-shaped double quantum dot detector, in which the qubit and double dot are arranged in such a unique way that the detector turns out to be particularly susceptible to the…

Mesoscale and Nanoscale Physics · Physics 2015-01-16 JunYan Luo , HuJun Jiao , Jing Hu , Xiao-Ling He , XiaoLi Lang , Shi-Kuan Wang

Electron spin qubits in silicon, whether in quantum dots or in donor atoms, have long been considered attractive qubits for the implementation of a quantum computer due to the semiconductor vacuum character of silicon and its compatibility…

Mesoscale and Nanoscale Physics · Physics 2015-09-02 M. Urdampilleta , A. Chatterjee , C. C. Lo , T. Kobayashi , J. Mansir , S. Barraud , A. C. Betz , S. Rogge , M. F. Gonzalez-Zalba , J. J. L. Morton

We present a theoretical and experimental study of photonic and electronic transport properties of a voltage biased InAs semiconductor double quantum dot (DQD) that is dipole-coupled to a superconducting transmission line resonator. We…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 Manas Kulkarni , Ovidiu Cotlet , Hakan E. Türeci

We consider qubit coupling resulting from the capacitive coupling between two double quantum dot (DQD) single-triplet qubits. Calculations of the coupling when the two DQDs are detuned symmetrically or asymmetrically are performed using a…

Mesoscale and Nanoscale Physics · Physics 2013-05-30 Erik Nielsen , Richard P. Muller , Malcolm S. Carroll

We consider a double dot system of equivalent, capacitively coupled semiconducting quantum dots, each coupled to its own lead, in a regime where there are two electrons on the double dot. Employing the numerical renormalization group, we…

Strongly Correlated Electrons · Physics 2007-05-23 Martin R. Galpin , David E. Logan , H. R. Krishnamurthy

We study the dynamics of a charge qubit, consisting of a single electron in a double well potential coupled to a point-contact (PC) electrometer, using the quantum trajectories formalism. Contrary to previous predictions, we show formally…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 T. M. Stace , S. D. Barrett

We theoretically investigate charge transport through serial double quantum dots (SDQDs) with strong electron correlations using nonequilibrium Green's function techniques. In the linear response regime, we compute the charge stability…

Mesoscale and Nanoscale Physics · Physics 2025-04-29 David M T Kuo

The transport properties of serially coupled quantum dots (SCQDs) embedded in a matrix connected to metallic electrodes are theoretically studied in the linear and nonlinear regimes. The current rectification and negative differential…

Mesoscale and Nanoscale Physics · Physics 2015-06-12 Yen-Chun Tseng , David M. -T. Kuo

We theoretically investigate transport signatures of quantum interference in highly symmetric double quantum dots in a parallel geometry and demonstrate that extremely weak symmetry-breaking effects can have a dramatic influence on the…

Mesoscale and Nanoscale Physics · Physics 2019-03-06 Zeng-Zhao Li , Martin Leijnse

We present a proposal for a fully electrically controllable quantum dot based spin current injector. The device consists of a quantum dot that is strongly coupled to a ferromagnetic electrode on one side and weakly coupled to a nonmagnetic…

Mesoscale and Nanoscale Physics · Physics 2012-10-23 Szabolcs Csonka , Ireneusz Weymann , Gergely Zarand

We present a microscopic theory for both equilibrium and nonequilibrium transport properties of coupled double quantum dots (DQD). A general formula for current tunneling through the DQD is derived by the nonequilibrium Green's function…

Mesoscale and Nanoscale Physics · Physics 2009-10-28 Jun Zang , Joseph L Birman , A. R. Bishop , L. Wang

Inherent randomness and the resulting stochastic behavior of fundamental particles manifested as quantum noise put a lower bound on measurement imprecision in the quantum measurement process. In addition, the quantum noise imparts…

Mesoscale and Nanoscale Physics · Physics 2025-01-22 Prasanta Kumbhakar , Anusha Shanmugam , Akhileshwar Mishra , Ravi Pant , J L Reno , S Addamane , Madhu Thalakulam