Improving intrinsic decoherence in multiple-quantum-dot charge qubits

    Authors

    M. Hentschel; D. C. B. Valente; E. R. Mucciolo;H. U. Baranger

    Comments

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    Abbreviated Journal Title

    Phys. Rev. B

    Keywords

    DYNAMICS; OSCILLATIONS; COMPUTATION; SPIN; Physics, Condensed Matter

    Abstract

    We discuss decoherence in charge qubits formed by multiple lateral quantum dots in the framework of the spin-boson model and the Born-Markov approximation. We consider the intrinsic decoherence caused by the coupling to bulk phonon modes. Two distinct quantum dot configurations are studied: (i) Three quantum dots in a ring geometry with one excess electron in total and (ii) arrays of quantum dots where the computational basis states form multipole charge configurations. For the three-dot qubit, we demonstrate the possibility of performing one- and two-qubit operations by solely tuning gate voltages. Compared to a previous proposal involving a linear three-dot spin qubit, the three-dot charge qubit allows for less overhead on two-qubit operations. For small interdot tunnel amplitudes, the three-dot qubits have Q factors much higher than those obtained for double-dot systems. The high-multipole dot configurations also show a substantial decrease in decoherence at low operation frequencies when compared to the double-dot qubit.

    Journal Title

    Physical Review B

    Volume

    76

    Issue/Number

    23

    Publication Date

    1-1-2007

    Document Type

    Article

    Language

    English

    First Page

    12

    WOS Identifier

    WOS:000251986500068

    ISSN

    1098-0121

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