1
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Wang CA, John V, Tidjani H, Yu CX, Ivlev AS, Déprez C, van Riggelen-Doelman F, Woods BD, Hendrickx NW, Lawrie WIL, Stehouwer LEA, Oosterhout SD, Sammak A, Friesen M, Scappucci G, de Snoo SL, Rimbach-Russ M, Borsoi F, Veldhorst M. Operating semiconductor quantum processors with hopping spins. Science 2024; 385:447-452. [PMID: 39052794 DOI: 10.1126/science.ado5915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 06/14/2024] [Indexed: 07/27/2024]
Abstract
Qubits that can be efficiently controlled are essential for the development of scalable quantum hardware. Although resonant control is used to execute high-fidelity quantum gates, the scalability is challenged by the integration of high-frequency oscillating signals, qubit cross-talk, and heating. Here, we show that by engineering the hopping of spins between quantum dots with a site-dependent spin quantization axis, quantum control can be established with discrete signals. We demonstrate hopping-based quantum logic and obtain single-qubit gate fidelities of 99.97%, coherent shuttling fidelities of 99.992% per hop, and a two-qubit gate fidelity of 99.3%, corresponding to error rates that have been predicted to allow for quantum error correction. We also show that hopping spins constitute a tuning method by statistically mapping the coherence of a 10-quantum dot system. Our results show that dense quantum dot arrays with sparse occupation could be developed for efficient and high-connectivity qubit registers.
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Affiliation(s)
- Chien-An Wang
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Valentin John
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Hanifa Tidjani
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Cécile X Yu
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Alexander S Ivlev
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Corentin Déprez
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | | | - Benjamin D Woods
- Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Nico W Hendrickx
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - William I L Lawrie
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Lucas E A Stehouwer
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Stefan D Oosterhout
- QuTech and Netherlands Organisation for Applied Scientific Research (TNO), 2628 CK Delft, Netherlands
| | - Amir Sammak
- QuTech and Netherlands Organisation for Applied Scientific Research (TNO), 2628 CK Delft, Netherlands
| | - Mark Friesen
- Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Giordano Scappucci
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Sander L de Snoo
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Maximilian Rimbach-Russ
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Francesco Borsoi
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Menno Veldhorst
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, Netherlands
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2
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Cifuentes JD, Tanttu T, Gilbert W, Huang JY, Vahapoglu E, Leon RCC, Serrano S, Otter D, Dunmore D, Mai PY, Schlattner F, Feng M, Itoh K, Abrosimov N, Pohl HJ, Thewalt M, Laucht A, Yang CH, Escott CC, Lim WH, Hudson FE, Rahman R, Dzurak AS, Saraiva A. Bounds to electron spin qubit variability for scalable CMOS architectures. Nat Commun 2024; 15:4299. [PMID: 38769086 PMCID: PMC11106088 DOI: 10.1038/s41467-024-48557-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 05/06/2024] [Indexed: 05/22/2024] Open
Abstract
Spins of electrons in silicon MOS quantum dots combine exquisite quantum properties and scalable fabrication. In the age of quantum technology, however, the metrics that crowned Si/SiO2 as the microelectronics standard need to be reassessed with respect to their impact upon qubit performance. We chart spin qubit variability due to the unavoidable atomic-scale roughness of the Si/SiO2 interface, compiling experiments across 12 devices, and develop theoretical tools to analyse these results. Atomistic tight binding and path integral Monte Carlo methods are adapted to describe fluctuations in devices with millions of atoms by directly analysing their wavefunctions and electron paths instead of their energy spectra. We correlate the effect of roughness with the variability in qubit position, deformation, valley splitting, valley phase, spin-orbit coupling and exchange coupling. These variabilities are found to be bounded, and they lie within the tolerances for scalable architectures for quantum computing as long as robust control methods are incorporated.
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Affiliation(s)
- Jesús D Cifuentes
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia.
| | - Tuomo Tanttu
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Will Gilbert
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Jonathan Y Huang
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
| | - Ensar Vahapoglu
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Ross C C Leon
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
| | - Santiago Serrano
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
| | - Dennis Otter
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
| | - Daniel Dunmore
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
| | - Philip Y Mai
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
| | - Frédéric Schlattner
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Solid State Physics Laboratory, Department of Physics, ETH Zurich, Zurich, 8093, Switzerland
| | - MengKe Feng
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
| | - Kohei Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama, Japan
| | | | | | - Michael Thewalt
- Department of Physics, Simon Fraser University, V5A 1S6, Burnaby, BC, Canada
| | - Arne Laucht
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Chih Hwan Yang
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Christopher C Escott
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Wee Han Lim
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Fay E Hudson
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Rajib Rahman
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Andrew S Dzurak
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia
- Diraq, Sydney, NSW, Australia
| | - Andre Saraiva
- School of Electrical Engineering and Telecommunications, University of New South Wales, NSW 2052, Sydney, NSW, Australia.
- Diraq, Sydney, NSW, Australia.
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3
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Neyens S, Zietz OK, Watson TF, Luthi F, Nethwewala A, George HC, Henry E, Islam M, Wagner AJ, Borjans F, Connors EJ, Corrigan J, Curry MJ, Keith D, Kotlyar R, Lampert LF, Mądzik MT, Millard K, Mohiyaddin FA, Pellerano S, Pillarisetty R, Ramsey M, Savytskyy R, Schaal S, Zheng G, Ziegler J, Bishop NC, Bojarski S, Roberts J, Clarke JS. Probing single electrons across 300-mm spin qubit wafers. Nature 2024; 629:80-85. [PMID: 38693414 PMCID: PMC11062914 DOI: 10.1038/s41586-024-07275-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 03/05/2024] [Indexed: 05/03/2024]
Abstract
Building a fault-tolerant quantum computer will require vast numbers of physical qubits. For qubit technologies based on solid-state electronic devices1-3, integrating millions of qubits in a single processor will require device fabrication to reach a scale comparable to that of the modern complementary metal-oxide-semiconductor (CMOS) industry. Equally important, the scale of cryogenic device testing must keep pace to enable efficient device screening and to improve statistical metrics such as qubit yield and voltage variation. Spin qubits1,4,5 based on electrons in Si have shown impressive control fidelities6-9 but have historically been challenged by yield and process variation10-12. Here we present a testing process using a cryogenic 300-mm wafer prober13 to collect high-volume data on the performance of hundreds of industry-manufactured spin qubit devices at 1.6 K. This testing method provides fast feedback to enable optimization of the CMOS-compatible fabrication process, leading to high yield and low process variation. Using this system, we automate measurements of the operating point of spin qubits and investigate the transitions of single electrons across full wafers. We analyse the random variation in single-electron operating voltages and find that the optimized fabrication process leads to low levels of disorder at the 300-mm scale. Together, these results demonstrate the advances that can be achieved through the application of CMOS-industry techniques to the fabrication and measurement of spin qubit devices.
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4
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Borsoi F, Hendrickx NW, John V, Meyer M, Motz S, van Riggelen F, Sammak A, de Snoo SL, Scappucci G, Veldhorst M. Shared control of a 16 semiconductor quantum dot crossbar array. NATURE NANOTECHNOLOGY 2024; 19:21-27. [PMID: 37640909 PMCID: PMC10796274 DOI: 10.1038/s41565-023-01491-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 07/20/2023] [Indexed: 08/31/2023]
Abstract
The efficient control of a large number of qubits is one of the most challenging aspects for practical quantum computing. Current approaches in solid-state quantum technology are based on brute-force methods, where each and every qubit requires at least one unique control line-an approach that will become unsustainable when scaling to the required millions of qubits. Here, inspired by random-access architectures in classical electronics, we introduce the shared control of semiconductor quantum dots to efficiently operate a two-dimensional crossbar array in planar germanium. We tune the entire array, comprising 16 quantum dots, to the few-hole regime. We then confine an odd number of holes in each site to isolate an unpaired spin per dot. Moving forward, we demonstrate on a vertical and a horizontal double quantum dot a method for the selective control of the interdot coupling and achieve a tunnel coupling tunability over more than 10 GHz. The operation of a quantum electronic device with fewer control terminals than tunable experimental parameters represents a compelling step forward in the construction of scalable quantum technology.
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Affiliation(s)
- Francesco Borsoi
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
| | - Nico W Hendrickx
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Valentin John
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Marcel Meyer
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Sayr Motz
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Floor van Riggelen
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Amir Sammak
- QuTech and Netherlands Organisation for Applied Scientific Research (TNO), Delft, The Netherlands
| | - Sander L de Snoo
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Giordano Scappucci
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Menno Veldhorst
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
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5
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Meyer M, Déprez C, Meijer IN, Unseld FK, Karwal S, Sammak A, Scappucci G, Vandersypen LMK, Veldhorst M. Single-Electron Occupation in Quantum Dot Arrays at Selectable Plunger Gate Voltage. NANO LETTERS 2023; 23:11593-11600. [PMID: 38091376 PMCID: PMC10755753 DOI: 10.1021/acs.nanolett.3c03349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/28/2023]
Abstract
The small footprint of semiconductor qubits is favorable for scalable quantum computing. However, their size also makes them sensitive to their local environment and variations in the gate structure. Currently, each device requires tailored gate voltages to confine a single charge per quantum dot, clearly challenging scalability. Here, we tune these gate voltages and equalize them solely through the temporary application of stress voltages. In a double quantum dot, we reach a stable (1,1) charge state at identical and predetermined plunger gate voltage and for various interdot couplings. Applying our findings, we tune a 2 × 2 quadruple quantum dot such that the (1,1,1,1) charge state is reached when all plunger gates are set to 1 V. The ability to define required gate voltages may relax requirements on control electronics and operations for spin qubit devices, providing means to advance quantum hardware.
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Affiliation(s)
- Marcel Meyer
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The
Netherlands
| | - Corentin Déprez
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The
Netherlands
| | - Ilja N. Meijer
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The
Netherlands
| | - Florian K. Unseld
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The
Netherlands
| | - Saurabh Karwal
- QuTech
and Netherlands Organisation for Applied Scientific Research (TNO), PO Box 155, 2600 AD Delft, The Netherlands
| | - Amir Sammak
- QuTech
and Netherlands Organisation for Applied Scientific Research (TNO), PO Box 155, 2600 AD Delft, The Netherlands
| | - Giordano Scappucci
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The
Netherlands
| | - Lieven M. K. Vandersypen
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The
Netherlands
| | - Menno Veldhorst
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The
Netherlands
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6
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Meyer M, Déprez C, van Abswoude TR, Meijer IN, Liu D, Wang CA, Karwal S, Oosterhout S, Borsoi F, Sammak A, Hendrickx NW, Scappucci G, Veldhorst M. Electrical Control of Uniformity in Quantum Dot Devices. NANO LETTERS 2023; 23:2522-2529. [PMID: 36975126 PMCID: PMC10103318 DOI: 10.1021/acs.nanolett.2c04446] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 03/20/2023] [Indexed: 06/18/2023]
Abstract
Highly uniform quantum systems are essential for the practical implementation of scalable quantum processors. While quantum dot spin qubits based on semiconductor technology are a promising platform for large-scale quantum computing, their small size makes them particularly sensitive to their local environment. Here, we present a method to electrically obtain a high degree of uniformity in the intrinsic potential landscape using hysteretic shifts of the gate voltage characteristics. We demonstrate the tuning of pinch-off voltages in quantum dot devices over hundreds of millivolts that then remain stable at least for hours. Applying our method, we homogenize the pinch-off voltages of the plunger gates in a linear array for four quantum dots, reducing the spread in pinch-off voltages by one order of magnitude. This work provides a new tool for the tuning of quantum dot devices and offers new perspectives for the implementation of scalable spin qubit arrays.
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Affiliation(s)
- Marcel Meyer
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Corentin Déprez
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Timo R. van Abswoude
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Ilja N. Meijer
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Dingshan Liu
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Chien-An Wang
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Saurabh Karwal
- QuTech
and Netherlands Organisation for Applied Scientific Research (TNO), PO Box 155, 2600 AD Delft, The Netherlands
| | - Stefan Oosterhout
- QuTech
and Netherlands Organisation for Applied Scientific Research (TNO), PO Box 155, 2600 AD Delft, The Netherlands
| | - Francesco Borsoi
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Amir Sammak
- QuTech
and Netherlands Organisation for Applied Scientific Research (TNO), PO Box 155, 2600 AD Delft, The Netherlands
| | - Nico W. Hendrickx
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Giordano Scappucci
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
| | - Menno Veldhorst
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
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7
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Weinstein AJ, Reed MD, Jones AM, Andrews RW, Barnes D, Blumoff JZ, Euliss LE, Eng K, Fong BH, Ha SD, Hulbert DR, Jackson CAC, Jura M, Keating TE, Kerckhoff J, Kiselev AA, Matten J, Sabbir G, Smith A, Wright J, Rakher MT, Ladd TD, Borselli MG. Universal logic with encoded spin qubits in silicon. Nature 2023; 615:817-822. [PMID: 36746190 PMCID: PMC10060158 DOI: 10.1038/s41586-023-05777-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 01/31/2023] [Indexed: 02/08/2023]
Abstract
Quantum computation features known examples of hardware acceleration for certain problems, but is challenging to realize because of its susceptibility to small errors from noise or imperfect control. The principles of fault tolerance may enable computational acceleration with imperfect hardware, but they place strict requirements on the character and correlation of errors1. For many qubit technologies2-21, some challenges to achieving fault tolerance can be traced to correlated errors arising from the need to control qubits by injecting microwave energy matching qubit resonances. Here we demonstrate an alternative approach to quantum computation that uses energy-degenerate encoded qubit states controlled by nearest-neighbour contact interactions that partially swap the spin states of electrons with those of their neighbours. Calibrated sequences of such partial swaps, implemented using only voltage pulses, allow universal quantum control while bypassing microwave-associated correlated error sources1,22-28. We use an array of six 28Si/SiGe quantum dots, built using a platform that is capable of extending in two dimensions following processes used in conventional microelectronics29. We quantify the operational fidelity of universal control of two encoded qubits using interleaved randomized benchmarking30, finding a fidelity of 96.3% ± 0.7% for encoded controlled NOT operations and 99.3% ± 0.5% for encoded SWAP. The quantum coherence offered by enriched silicon5-9,16,18,20,22,27,29,31-37, the all-electrical and low-crosstalk-control of partial swap operations1,22-28 and the configurable insensitivity of our encoding to certain error sources28,33,34,38 all combine to offer a strong pathway towards scalable fault tolerance and computational advantage.
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Affiliation(s)
| | | | | | | | | | | | | | - Kevin Eng
- HRL Laboratories, LLC, Malibu, CA, USA
| | | | - Sieu D Ha
- HRL Laboratories, LLC, Malibu, CA, USA
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8
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Noiri A, Takeda K, Nakajima T, Kobayashi T, Sammak A, Scappucci G, Tarucha S. A shuttling-based two-qubit logic gate for linking distant silicon quantum processors. Nat Commun 2022; 13:5740. [PMID: 36180449 PMCID: PMC9525571 DOI: 10.1038/s41467-022-33453-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 09/16/2022] [Indexed: 12/04/2022] Open
Abstract
Control of entanglement between qubits at distant quantum processors using a two-qubit gate is an essential function of a scalable, modular implementation of quantum computation. Among the many qubit platforms, spin qubits in silicon quantum dots are promising for large-scale integration along with their nanofabrication capability. However, linking distant silicon quantum processors is challenging as two-qubit gates in spin qubits typically utilize short-range exchange coupling, which is only effective between nearest-neighbor quantum dots. Here we demonstrate a two-qubit gate between spin qubits via coherent spin shuttling, a key technology for linking distant silicon quantum processors. Coherent shuttling of a spin qubit enables efficient switching of the exchange coupling with an on/off ratio exceeding 1000, while preserving the spin coherence by 99.6% for the single shuttling between neighboring dots. With this shuttling-mode exchange control, we demonstrate a two-qubit controlled-phase gate with a fidelity of 93%, assessed via randomized benchmarking. Combination of our technique and a phase coherent shuttling of a qubit across a large quantum dot array will provide feasible path toward a quantum link between distant silicon quantum processors, a key requirement for large-scale quantum computation. A coherent quantum link between distant quantum processors is desirable for scaling up of quantum computation. Noiri et al. demonstrate a strategy to link distant quantum processors in silicon, by implementing a shuttling-based two-qubit gate between spin qubits in a Si/SiGe triple quantum dot.
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Affiliation(s)
- Akito Noiri
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan.
| | - Kenta Takeda
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | | | | | - Amir Sammak
- QuTech, Delft University of Technology, Delft, The Netherlands.,Netherlands Organization for Applied Scientific Research (TNO), Delft, The Netherlands
| | - Giordano Scappucci
- QuTech, Delft University of Technology, Delft, The Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Seigo Tarucha
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan. .,RIKEN Center for Quantum Computing (RQC), Wako, Japan.
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9
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Takeda K, Noiri A, Nakajima T, Kobayashi T, Tarucha S. Quantum error correction with silicon spin qubits. Nature 2022; 608:682-686. [PMID: 36002485 PMCID: PMC9402442 DOI: 10.1038/s41586-022-04986-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 06/16/2022] [Indexed: 11/09/2022]
Abstract
Future large-scale quantum computers will rely on quantum error correction (QEC) to protect the fragile quantum information during computation1,2. Among the possible candidate platforms for realizing quantum computing devices, the compatibility with mature nanofabrication technologies of silicon-based spin qubits offers promise to overcome the challenges in scaling up device sizes from the prototypes of today to large-scale computers3-5. Recent advances in silicon-based qubits have enabled the implementations of high-quality one-qubit and two-qubit systems6-8. However, the demonstration of QEC, which requires three or more coupled qubits1, and involves a three-qubit gate9-11 or measurement-based feedback, remains an open challenge. Here we demonstrate a three-qubit phase-correcting code in silicon, in which an encoded three-qubit state is protected against any phase-flip error on one of the three qubits. The correction to this encoded state is performed by a three-qubit conditional rotation, which we implement by an efficient single-step resonantly driven iToffoli gate. As expected, the error correction mitigates the errors owing to one-qubit phase-flip, as well as the intrinsic dephasing mainly owing to quasi-static phase noise. These results show successful implementation of QEC and the potential of a silicon-based platform for large-scale quantum computing.
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Affiliation(s)
- Kenta Takeda
- Center for Emergent Matter Science (CEMS), RIKEN, Wako, Japan.
| | - Akito Noiri
- Center for Emergent Matter Science (CEMS), RIKEN, Wako, Japan
| | | | | | - Seigo Tarucha
- Center for Emergent Matter Science (CEMS), RIKEN, Wako, Japan.
- Center for Quantum Computing (RQC), RIKEN, Wako, Japan.
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10
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Mills AR, Guinn CR, Gullans MJ, Sigillito AJ, Feldman MM, Nielsen E, Petta JR. Two-qubit silicon quantum processor with operation fidelity exceeding 99. SCIENCE ADVANCES 2022; 8:eabn5130. [PMID: 35385308 PMCID: PMC8986105 DOI: 10.1126/sciadv.abn5130] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/23/2022] [Indexed: 05/20/2023]
Abstract
Silicon spin qubits satisfy the necessary criteria for quantum information processing. However, a demonstration of high-fidelity state preparation and readout combined with high-fidelity single- and two-qubit gates, all of which must be present for quantum error correction, has been lacking. We use a two-qubit Si/SiGe quantum processor to demonstrate state preparation and readout with fidelity greater than 97%, combined with both single- and two-qubit control fidelities exceeding 99%. The operation of the quantum processor is quantitatively characterized using gate set tomography and randomized benchmarking. Our results highlight the potential of silicon spin qubits to become a dominant technology in the development of intermediate-scale quantum processors.
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Affiliation(s)
- Adam R. Mills
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Charles R. Guinn
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Michael J. Gullans
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, MD 20742, USA
| | | | - Mayer M. Feldman
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Erik Nielsen
- Sandia National Laboratories, Albuquerque, NM 87185, USA
| | - Jason R. Petta
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Corresponding author.
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11
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Jia Z, Fu Y, Cao Z, Cheng W, Zhao Y, Dou M, Duan P, Kong W, Cao G, Li H, Guo G. Superconducting and Silicon-Based Semiconductor Quantum Computers: A Review. IEEE NANOTECHNOLOGY MAGAZINE 2022. [DOI: 10.1109/mnano.2022.3175394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zhilong Jia
- University of Science and Technology of China
| | - Yaobin Fu
- Hefei Origin Quantum Computing Technology
| | - Zhen Cao
- Hefei Origin Quantum Computing Technology
| | | | | | | | - Peng Duan
- University of Science and Technology of China
| | | | - Gang Cao
- University of Science and Technology of China
| | - Haiou Li
- University of Science and Technology of China
| | - Guoping Guo
- University of Science and Technology of China
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