Title

Improving intrinsic decoherence in multiple-quantum-dot charge qubits

Authors

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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