Intrinsic exciton-exciton coupling in GaN-based quantum dots: Application to solid-state quantum computing

Rinaldis, S. De; D’Amico, Irene; Biolatti, Eliana; Rinaldi, R.; Cingolani, R.; Rossi, Fausto

doi:10.1103/physrevb.65.081309

Cited by 99 publications

(88 citation statements)

References 11 publications

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“…This leads to a strong intrinsic electric field 24 , which enhances coupling between excitons in neighboring quantum dots within a stack 5 . We calculate the built-in electric fields inside the quantum dots by considering an alternating sequence of quantum wells and barriers: results are in good agreement with experimental findings 5 , showing that the lateral shape of the dot is mainly responsible for the strong in-plane carrier confinement. Quantum computation can then be carried out by using sequences of laser pulses, as described in Ref.…”

Section: System and Redundant Encodingmentioning

confidence: 99%

“…The presence of an exciton in a QD produces a biexcitonic shift in the ground state excitonic energy of a nearby QD. By driving a qubit at this shifted frequency conditional operations can be performed 4,5 .…”

Section: Introductionmentioning

confidence: 99%

“…This poses a problem for driving optically the response of self assembled quantum dot ensembles (such as the ones grown by StranskiKrastanow techniques): in these ensembles the size of each dot is one order of magnitude smaller than the laser spot addressing it. To this end it has been proposed to use energy selective methods on isolated stacks of quantum dots (quantum registers) 4,5 . However, it is still experimentally difficult to control QD size and position in a satisfactory way, and QD vertical stacks tend to form in the plane at random positions.…”

Section: Introductionmentioning

confidence: 99%

“…Among the various proposals are schemes which rely on spin and exciton qubits confined in semiconductor quantum dots (QD) 2 , which can be manipulated using ultra fast laser pulses 3 . Several of these optical quantum computation schemes rely on exciton-exciton direct Coulomb interaction, which provides the necessary coupling to perform two qubit gates 4,5 . The presence of an exciton in a QD produces a biexcitonic shift in the ground state excitonic energy of a nearby QD.…”

Section: Introductionmentioning

confidence: 99%

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Mesoporous matrices for quantum computation with improved response through redundance

Hodgson

Bertino

Leventis

et al. 2007

Journal of Applied Physics

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We present a solid state implementation of quantum computation, which improves previously proposed optically driven schemes. Our proposal is based on vertical arrays of quantum dots embedded in a mesoporous material which can be fabricated with present technology. The redundant encoding typical of the chosen hardware protects the computation against gate errors and the effects of measurement induced noise. The system parameters required for quantum computation applications are calculated for II-VI and III-V materials and found to be within the experimental range. The proposed hardware may help minimize errors due to polydispersity of dot sizes, which is at present one of the main problems in relation to quantum dot-based quantum computation. (c) 2007 American Institute of Physics

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Section: System and Redundant Encodingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mesoporous matrices for quantum computation with improved response through redundance

Hodgson

Bertino

Leventis

et al. 2007

Journal of Applied Physics

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“…The lattermost effect is weak in InAs/GaAs systems but may be of more importance for the properties e.g. of GaN dots [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Fast Control of Quantum States in Quantum Dots: Limits due to Decoherence

Jacak

Machnikowski

Krasnyj

Quantum Dots: Fundamentals, Applications, and Frontiers

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We study the kinetics of confined carrier-phonon system in a quantum dot under fast optical driving and discuss the resulting limitations to fast coherent control over the quantum state in such systems. IntroductionUnlike natural atoms, semiconductor quantum dots (QDs) always form part of a macroscopic crystal. The interaction with the quasicontinuum of lattice degrees of freedom (phonons) constitutes an inherent feature of these nanometer-size systems and cannot be neglected in any realistic modeling of QD properties, especially when the coherence of confined carriers is of importance. The understanding of the decisive role played by the QD coupling to lattice modes has increased recently due to both experimental and theoretical study (spectrum reconstruction [1-4], relaxation [5][6][7][8][9][10], phonon replicas and phonon-assisted transitions [11][12][13][14][15][16], phonon-induced pure dephasing upon ultrafast excitation [17][18][19][20][21][22]). The phonon-induced decoherence seems to be crucial for any quantum information processing application and for any nanotechnological device relying on quantum coherence of confined carriers [23,24].There are three major mechanisms of carrier-phonon interaction [25]: (1) Coulomb interaction with the lattice polarization induced by the relative shift of the positive and negative sub-lattices of the polar compound, * On leave from Odessa University, Ukraine

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Quantum Information/Computation Processing with Self-Assembled Macroatoms

D’Amico

Rinaldis

Zanardi

et al. 2002

phys. stat. sol. (b)

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We shall present a review of quantum dot based schemes for the implementation of quantum information processing. We shall compare two potential implementations which use charge degrees of freedom and different kinds of self-assembled quantum dots. The computational degrees of freedom are interband optical transitions driven by ultrafast sequences of multicolor laser-pulse trains. The proposed implementations exploit exciton-exciton interactions induced by an in-plane external electric field in the case of GaAs-based quantum dot structures, and by the strong built-in electric field in GaN-based heterostructures.1. Introduction Semiconductor quantum dots (QDs) are quasi zero-dimensional (0D) systems [1]. Compared to systems of higher dimensionality -like quantum wells and wires -they have a discrete energy spectrum and they exhibit genuine few-carrier effects. Such quasi 0D nanostructures are often referred to as semiconductor macroatoms. Apart from their relevance in terms of basic physics, QDs have attracted general attention because of their technological applications: these range from laser emitters [2] to charge-storage devices [3], from fluorescent biological markers [4] to quantum information processing devices [5]. In QDs, the flexibility typical of semiconductors in controlling carrier densities has been brought to its extreme: it is possible to electrically inject single electrons [6] or to photo-generate a single Coulomb-correlated electron-hole pair, i.e. a single exciton, in a QD [7,8]. It is even possible to detect the single-exciton decaying energy emission [7,8]. The quantized, atomic-like, energy structure of QDs allows for a rich optical spectrum and for a weak interaction of the QD system with environmental degrees of freedom (like phonons, plasmons, etc.), i.e. for an almost decoherence-free quantum evolution of the carrier subsystem [9,11]. Moreover, their reduced spatial extension -up to few nanometers -leads to an increase of two-body interactions among carriers and to stronger Coulomb-correlation effects [10]. The latter may be used to design a variety of single-electron devices. In particular, they can be employed to design full-optical quantum gates, as recently proposed in Refs. [11,12].

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Intrinsic exciton-exciton coupling in GaN-based quantum dots: Application to solid-state quantum computing

Cited by 99 publications

References 11 publications

Mesoporous matrices for quantum computation with improved response through redundance

Mesoporous matrices for quantum computation with improved response through redundance

Fast Control of Quantum States in Quantum Dots: Limits due to Decoherence

Quantum Information/Computation Processing with Self-Assembled Macroatoms

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