Title

Improving Intrinsic Decoherence In Multiple-Quantum-Dot Charge Qubits

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. © 2007 The American Physical Society.

Publication Date

12-12-2007

Publication Title

Physical Review B - Condensed Matter and Materials Physics

Volume

76

Issue

23

Number of Pages

-

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1103/PhysRevB.76.235309

Socpus ID

37249079699 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/37249079699

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