Triple quantum dot device designed for three spin qubits

Takakura, T.; Pioro‐Ladrière, Michel; Obata, T.; Shin, Yoojin; Brunner, Roland; Yoshida, Kazushi; Taniyama, Tomoyasu; Tarucha, Seigo

doi:10.1063/1.3518919

Cited by 50 publications

(47 citation statements)

References 14 publications

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“…Here we examine the validity range of the Gaussian approximation, as the number of fluctuators is increased, and its dependence on the number of control pulses. As current experimental efforts are focused on more complicated QD structures, such as two coupled double QDs, 26,35 and three-spin qubits in triple-dots, [36][37][38] the resulting larger devices are expected to have a noisier charge environment. Understanding how qubit decoherence scales with the number of TLFs is therefore important.…”

Section: Introductionmentioning

confidence: 99%

Non-Gaussian signatures and collective effects in charge noise affecting a dynamically decoupled qubit

Ramon

2015

Phys. Rev. B

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The effects of a collection of classical two-level charge fluctuators on the coherence of a dynamicallydecoupled qubit are studied. Distinct dynamics are found at different qubit working positions. Exact analytical formulae are derived at pure dephasing and approximate solutions are found at the general working position, for weakly-and strongly-coupled fluctuators. Analysis of these solutions, combined with numerical simulations of the multiple random telegraph processes, reveal the scaling of the noise with the number of fluctuators and the number of control pulses, as well as dependence on other parameters of the qubit-fluctuators system. These results can be used to determine potential microscopic models for the charge environment by performing noise spectroscopy.

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Section: Introductionmentioning

confidence: 99%

Non-Gaussian signatures and collective effects in charge noise affecting a dynamically decoupled qubit

Ramon

2015

Phys. Rev. B

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“…Instead, we suggest that the use of so-called exchangeonly qubits [10,11], comprising three spins in a triple quantum dot [12][13][14][15][16][17] and implemented experimentally [18][19][20][21], provide an opportunity for protection against low-frequency control noise in analogy to advances in superconducting devices [22]. In particular, by having exchange couplings always on, a regime with no low-frequency field response and a narrowband, resonant response becomes accessible.…”

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confidence: 99%

Electrically Protected Resonant Exchange Qubits in Triple Quantum Dots

2013

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We present a modulated microwave approach for quantum computing with qubits comprising three spins in a triple quantum dot. This approach includes single-and two-qubit gates that are protected against low-frequency electrical noise, due to an operating point with a narrowband response to high frequency electric fields. Furthermore, existing double quantum dot advances, including robust preparation and measurement via spin-to-charge conversion, are immediately applicable to the new qubit. Finally, the electric dipole terms implicit in the high frequency coupling enable strong coupling with superconducting microwave resonators, leading to more robust two-qubit gates. PACS numbers:Spins in quantum dots as an architecture for quantum information processing require some combination of electric and magnetic field control at the nanometer scale [1]. While the intrinsic coherence properties of the spins can be remarkable, the need for such control inevitably couples the qubit degree of freedom to low-frequency electric or magnetic noise [2][3][4][5][6][7][8]. Approaches that mitigate this coupling, via dynamical decoupling or composite pulse sequences, all require rapid 'pulsed gate' control either for individual qubits or for two-qubit gates, which in turn requires wide bandwidths for the control electronics. While this has led to a variety of advances in the field, paradoxically it also leads to the use of quantum bits as sensors, rather than as protected devices [9].Instead, we suggest that the use of so-called exchangeonly qubits [10,11], comprising three spins in a triple quantum dot [12][13][14][15][16][17] and implemented experimentally [18][19][20][21], provide an opportunity for protection against low-frequency control noise in analogy to advances in superconducting devices [22]. In particular, by having exchange couplings always on, a regime with no low-frequency field response and a narrowband, resonant response becomes accessible. We denote this the resonant exchange (RX) qubit, and refer the reader to the concurrent Ref. [23] for an experimental demonstration of these ideas. Furthermore, our approach has a protected two-qubit interaction via exchange [24,25] or via resonant dipole-dipole interactions. As coupling between qubits relies on electric fields rather than tunneling, devices could be implemented in a wide variety of potential materials such as two dimensional electron gas and nanowire depletion dots. Finally, we show that the dipolar nature of the RX qubit also enables strong coupling with high quality factor microwave cavities.The few electron regime of interest for our triple dot system we describe by the Hubbard model [15](1) where U is the individual dot charging energy, U c is the cross-charging energy, V i is the local potential set by applied gate voltages on dot i, t ij is the tunneling between dots i and j, and c † iσ is the creation operator for an electron on dot i with spin σ. For simplicity, we assume a linear array and set t 12 = t l , t 23 = t r , t 13 = 0, and have defined tunneling...

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“…Additional Ti/Au surface gates were added and used to locally deplete electrons to form gate-confined lateral quantum dots. The QD structures were optimized after carefully designing the surface gate geometry by performing an electrostatic potential calculation [17] based on the carrier density and the distance from the surface gate electrodes to the two-dimensional electron gas (2DEG).…”

Section: Sample Details and Characterizationmentioning

confidence: 99%

Tuning the electrically evaluated electron Landégfactor in GaAs quantum dots and quantum wells of different well widths

et al. 2014

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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Tuning the electrically evaluated electron Landé g factor in GaAs quantum dots and quantum wells of different well widths Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1103/PhysRevB.90.235310 Physics, 90, 23, 2014-12-11 PHYSICAL REVIEW B 90, 235310 (2014 Tuning the electrically evaluated electron Landé g factor in GaAs quantum dots and quantum wells of different well widths We evaluate the Landé g factor of electrons in quantum dots (QDs) fabricated from GaAs quantum well (QW) structures of different well width. We first determine the Landé electron g factor of the QWs through resistive detection of electron spin resonance and compare it to the enhanced electron g factor determined from analysis of the magnetotransport. Next, we form laterally defined quantum dots using these quantum wells and extract the electron g factor from analysis of the cotunneling and Kondo effect within the quantum dots. We conclude that the Landé electron g factor of the quantum dot is primarily governed by the electron g factor of the quantum well suggesting that well width is an ideal design parameter for g-factor engineering QDs. Physical Review B -Condensed Matter and Materials

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Triple quantum dot device designed for three spin qubits

Cited by 50 publications

References 14 publications

Non-Gaussian signatures and collective effects in charge noise affecting a dynamically decoupled qubit

Non-Gaussian signatures and collective effects in charge noise affecting a dynamically decoupled qubit

Electrically Protected Resonant Exchange Qubits in Triple Quantum Dots

Tuning the electrically evaluated electron Landégfactor in GaAs quantum dots and quantum wells of different well widths

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