Detection and control of charge states in a quintuple quantum dot

Ito, Takumi; Otsuka, Takeshi; Amaha, S.; Delbecq, Matthieu; Nakajima, Takashi; Yoneda, Jun; Takeda, Kenta; Allison, Giles; Noiri, Akito; Kawasaki, Kento; Tarucha, Seigo

doi:10.1038/srep39113

Cited by 45 publications

(44 citation statements)

References 37 publications

(45 reference statements)

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“…One platform that is particularly promising is that of electron spins in semiconductor quantum dots, due to their compatibility with the existing semiconductor industry, as well as to the fast electrical control and long coherence times available in these systems. Several different implementations of qubits using such electronic spins include the single-spin Loss-DiVincenzo qubit [2][3][4][5][6][7][8][9] , the singlet-triplet qubit [10][11][12][13][14][15][16]18,19,33 , the tripledot exchange-only qubit [20][21][22][23][24] , and "hybrid" qubits with three electrons in two dots [25][26][27] . While there has been much experimental progress on improving the fidelity of gate operations 3,13,15,28 , with fidelities as high as about 99% for single-qubit gates and about 90% for two-qubit gates having been demonstrated 29 , more work must still be done to comfortably exceed the 99% surface-code threshold for all gate operations.…”

Section: Introductionmentioning

confidence: 99%

Fast pulse sequences for dynamically corrected gates in singlet-triplet qubits

et al. 2017

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We present a set of experimentally feasible pulse sequences that implement any single-qubit gate on a singlet-triplet spin qubit and demonstrate that these new sequences are up to three times faster than existing sequences in the literature. We show that these sequences can be extended to incorporate built-in dynamical error correction, yielding gates that are robust to both charge and magnetic field noise and up to twice as fast as previous dynamically corrected gate schemes. We present a thorough comparison of the performance of our new sequences with that of several existing ones using randomized benchmarking, considering both quasistatic and 1/f α noise models. We provide our results both as a function of evolution time and as a function of the number of gates, which respectively yield both an effective coherence time and an estimate of the number of gates that can be performed within this coherence time. We determine which set of pulse sequences gives the best results for a wide range of noise strengths and power spectra. Overall, we find that the traditional, slower sequences perform best when there is no field noise or when the noise contains significant high-frequency components; otherwise, our new, fast sequences exhibit the best performance.

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Section: Introductionmentioning

confidence: 99%

Fast pulse sequences for dynamically corrected gates in singlet-triplet qubits

et al. 2017

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“…and the bottom portions give the parameters j i and φ i for the uncorrected identity I (9) given by Equation (27). As an example, we plot the error-corrected pulse sequence for the gate e To precisely quantitatively calculate the fidelity of the dynamically corrected gate operations using our pulse sequences starting with given error sets, a detailed randomized benchmarking analysis is necessary.…”

Section: Resultsmentioning

confidence: 99%

“…Several different platforms for realizing qubits exist, but our focus in this work will be on electronic spins in semiconductor quantum dots. Several different types of semiconductor quantum dot electron spin qubits exist, such as the single-spin exchange qubit [2][3][4][5][6][7][8][9] , the singlet-triplet twoelectron double-dot qubit [10][11][12][13][14][15][16][17][18][19] , the exchange-only threeelectron triple-dot qubit [20][21][22][23][24] , and the "hybrid" threeelectron double-dot qubit [25][26][27] . The semiconductor spin qubit platform has the advantages of being compatible with the existing semiconductor electronics industry as well as the ability to perform gates more quickly (using fast electrical pulses) than other platforms, such as superconducting and ion trap qubits.…”

Section: Introductionmentioning

confidence: 99%

Crosstalk error correction through dynamical decoupling of single-qubit gates in capacitively coupled singlet-triplet semiconductor spin qubits

2018

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In addition to magnetic field and electric charge noise adversely affecting spin qubit operations, performing single-qubit gates on one of multiple coupled singlet-triplet qubits presents a new challenge-crosstalk, which is inevitable (and must be minimized) in any multiqubit quantum computing architecture. We develop a set of dynamically-corrected pulse sequences that are designed to cancel the effects of both types of noise (i.e., field and charge) as well as crosstalk to leading order, and provide parameters for these corrected sequences for all 24 of the single-qubit Clifford gates. We then provide an estimate of the error as a function of the noise and capacitive coupling to compare the fidelity of our corrected gates to their uncorrected versions. Dynamical error correction protocols presented in this work are important for the next generation of singlet-triplet qubit devices where coupling among many qubits will become relevant.

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“…Studies on CB and PSB are now moving onto multiple QDs (MQDs) such as triple [12][13][14][15][16] , quadruple, and quintuple QDs [17][18][19][20] , where the charge states become subtler to distinguish and more complicated to control. In addition, the transport current through series of dots is strongly reduced except for the resonance points 12,14,21 .…”

Section: Introductionmentioning

confidence: 99%

Cotunneling spin blockade observed in a three-terminal triple quantum dot

et al. 2017

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Abstract:We prepare a triple quantum dot with a separate contact lead to each dot to study Pauli spin blockade in the tunnel-coupled three dots in a row. We measure the tunneling current flowing between the center dot and either the left or right dot with the left and right leads as a common source and the center lead as a drain. In the biased stability diagram, we establish Pauli spin blockade in the respective neighboring dots, with features similarly obtained in double quantum dot systems. We further realize Pauli spin blockade with two different conditions by tuning the inter-dot coupling gates: strong and weak inter-dot tunnel coupling regimes. In the strong-coupling regime we observe significant suppression of co-tunneling through the respective double dots due to Pauli spin blockade. We reveal the influence from the third dot in the triple dot device on this co-tunneling Pauli spin blockade and clarify that the co-tunneling Pauli spin blockade is lifted by the resonant coupling of excited states to the third dot level as well as spin exchange of the left and right dots with the adjacent reservoir.

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Detection and control of charge states in a quintuple quantum dot

Cited by 45 publications

References 37 publications

Fast pulse sequences for dynamically corrected gates in singlet-triplet qubits

Fast pulse sequences for dynamically corrected gates in singlet-triplet qubits

Crosstalk error correction through dynamical decoupling of single-qubit gates in capacitively coupled singlet-triplet semiconductor spin qubits

Cotunneling spin blockade observed in a three-terminal triple quantum dot

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