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Corley-Wiciak, C. (author), Richter, C. (author), Zoellner, M.H. (author), Zaitsev, I. (author), Manganelli, C.L. (author), Zatterin, E. (author), Schülli, T.U. (author), Corley-Wiciak, A.A. (author), Katzer, J. (author), Reichmann, F. (author), Klesse, W.M. (author), Hendrickx, N.W. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author), Virgilio, M. (author), Capellini, G. (author)A strained Ge quantum well, grown on a SiGe/Si virtual substrate and hosting two electrostatically defined hole spin qubits, is nondestructively investigated by synchrotron-based scanning X-ray diffraction microscopy to determine all its Bravais lattice parameters. This allows rendering the three-dimensional spatial dependence of the six strain...article 2023
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Meyer, M. (author), Déprez, C. (author), van Abswoude, T.R. (author), Meijer, I.N. (author), Liu, D. (author), Wang, C.A. (author), Karwal, S. (author), Oosterhout, S.D. (author), Borsoi, F. (author), Sammak, A. (author), Hendrickx, N.W. (author), Scappucci, G. (author), Veldhorst, M. (author)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...article 2023
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- Paquelet Wuetz, B. (author), Degli Esposti, D. (author), Zwerver, A.M.J. (author), Amitonov, S.V. (author), Botifoll, M. (author), Jordi, A. (author), Sammak, A. (author), Vandersypen, L.M.K. (author), Russ, M. (author), Scappucci, G. (author) article 2023
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Bonsen, T. (author), Harvey-Collard, P. (author), Russ, M. (author), Dijkema, J. (author), Sammak, A. (author), Scappucci, G. (author), Vandersypen, L.M.K. (author)Circuit quantum electrodynamics with electron spins (spin circuit QED) enables long-range interaction and single-shot readout of spin qubits, which pave the way to large-scale spin qubit processors. Recent experimental work reported an additional feature in the vacuum Rabi splitting of peaks in the resonator transmission spectrum, which has...article 2023
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Xue, X. (author), Russ, M. (author), Samkharadze, N. (author), Undseth, B. (author), Sammak, A. (author), Scappucci, G. (author), Vandersypen, L.M.K. (author)High-fidelity control of quantum bits is paramount for the reliable execution of quantum algorithms and for achieving fault tolerance—the ability to correct errors faster than they occur. The central requirement for fault tolerance is expressed in terms of an error threshold. Whereas the actual threshold depends on many details, a common target...article 2022
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Noiri, A. (author), Takeda, K. (author), Nakajima, T. (author), Kobayashi, T. (author), Sammak, A. (author), Scappucci, G. (author), Tarucha, S. (author)Fault-tolerant quantum computers that can solve hard problems rely on quantum error correction1. One of the most promising error correction codes is the surface code, which requires universal gate fidelities exceeding an error correction threshold of 99%. Among the many qubit platforms, only superconducting circuits, trapped ions and nitrogen...article 2022
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van Riggelen, F. (author), Lawrie, W.I.L. (author), Russ, M. (author), Hendrickx, N.W. (author), Sammak, A. (author), Rispler, M. (author), Terhal, B.M. (author), Scappucci, G. (author), Veldhorst, M. (author)The fault-tolerant operation of logical qubits is an important requirement for realizing a universal quantum computer. Spin qubits based on quantum dots have great potential to be scaled to large numbers because of their compatibility with standard semiconductor manufacturing. Here, we show that a quantum error correction code can be implemented...article 2022
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Paquelet Wuetz, B. (author), Losert, M.P. (author), Koelling, S. (author), Stehouwer, L.E.A. (author), Zwerver, A.M.J. (author), Philips, S.G.J. (author), Madzik, M.T. (author), Xue, X. (author), Zheng, G. (author), Lodari, M. (author), Amitonov, S.V. (author), Samkharadze, N. (author), Sammak, A. (author), Vandersypen, L.M.K. (author), Rahman, R. (author), Coppersmith, S.N. (author), Moutanabbir, O. (author), Friesen, M. (author), Scappucci, G. (author)Electron spins in Si/SiGe quantum wells suffer from nearly degenerate conduction band valleys, which compete with the spin degree of freedom in the formation of qubits. Despite attempts to enhance the valley energy splitting deterministically, by engineering a sharp interface, valley splitting fluctuations remain a serious problem for qubit...article 2022
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Noiri, A. (author), Takeda, K. (author), Nakajima, T. (author), Kobayashi, T. (author), Sammak, A. (author), Scappucci, G. (author), Tarucha, S. (author)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,...article 2022
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Philips, S.G.J. (author), Mądzik, M.T. (author), Amitonov, S.V. (author), de Snoo, S.L. (author), Russ, M. (author), Kalhor, N. (author), Volk, C. (author), Lawrie, W.I.L. (author), Brousse, D. (author), Tryputen, L. (author), Paquelet Wuetz, B. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author), Vandersypen, L.M.K. (author)Future quantum computers capable of solving relevant problems will require a large number of qubits that can be operated reliably1. However, the requirements of having a large qubit count and operating with high fidelity are typically conflicting. Spins in semiconductor quantum dots show long-term promise2,3 but demonstrations so far use between...article 2022
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Lodari, M. (author), Kong, O. (author), Rendell, M. (author), Tosato, A. (author), Sammak, A. (author), Veldhorst, M. (author), Hamilton, A.R. (author), Scappucci, G. (author)We demonstrate that a lightly-strained germanium channel ("// = −0.41%) in an undoped Ge/Si0.1Ge0.9 heterostructure field effect transistor supports a 2D hole gas with mobility in excess of 1 × 106 cm2/Vs and percolation density less than 5 × 1010 cm−2. This low disorder 2D hole system shows tunable fractional quantum Hall effect at low density...article 2022
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Harvey-Collard, P. (author), Dijkema, J. (author), Zheng, G. (author), Sammak, A. (author), Scappucci, G. (author), Vandersypen, L.M.K. (author)We report the coherent coupling of two electron spins at a distance via virtual microwave photons. Each spin is trapped in a silicon double quantum dot at either end of a superconducting resonator, achieving spin-photon couplings up to around gs/2π = 40 MHz. As the two spins are brought into resonance with each other, but detuned from the...article 2022
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Degli Esposti, D. (author), Paquelet Wuetz, B. (author), Fezzi, V. (author), Lodari, M. (author), Sammak, A. (author), Scappucci, G. (author)We grow 28Si/SiGe heterostructures by reduced-pressure chemical vapor deposition and terminate the stack without an epitaxial Si cap but with an amorphous Si-rich layer obtained by exposing the SiGe barrier to dichlorosilane at 500 °C. As a result, 28Si/SiGe heterostructure field-effect transistors feature a sharp semiconductor/dielectric...article 2022
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Tosato, A. (author), Ferrari, B. (author), Sammak, A. (author), Hamilton, A.R. (author), Veldhorst, M. (author), Virgilio, M. (author), Scappucci, G. (author)A hole bilayer in a strained germanium double quantum well is designed, fabricated, and studied. Magnetotransport characterization of double quantum well field-effect transistors as a function of gate voltage reveals the population of two hole channels with a high combined mobility of 3.34 × 105 cm2 V−1 s−1 and a low percolation density of 2.38 ...article 2022
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Prabowo, B. (author), Zheng, G. (author), Mehrpoo, M. (author), Patra, B. (author), Harvey-Collard, P. (author), Dijkema, J. (author), Sammak, A. (author), Scappucci, G. (author), Charbon, E. (author), Sebastiano, F. (author), Vandersypen, L.M.K. (author), Babaie, M. (author)Quantum computers (QC) promise to solve certain computational problems exponentially faster than a classical computer due to the superposition and entanglement properties of quantum bits (qubits). Among several qubit technologies, spin qubits are a promising candidate for large-scale QC, since (1) they have a small footprint allowing them to be...conference paper 2021
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Rossi, A. (author), Hendrickx, N.W. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author), Kataoka, M. (author)Single-charge pumps are the main candidates for quantum-based standards of the unit ampere because they can generate accurate and quantized electric currents. In order to approach the metrological requirements in terms of both accuracy and speed of operation, in the past decade there has been a focus on semiconductor-based devices. The use of a...article 2021
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Hendrickx, N.W. (author), Lawrie, W.I.L. (author), Russ, M. (author), van Riggelen, F. (author), de Snoo, S.L. (author), Schouten, R.N. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author)The prospect of building quantum circuits using advanced semiconductor manufacturing makes quantum dots an attractive platform for quantum information processing. Extensive studies of various materials have led to demonstrations of two-qubit logic in gallium arsenide, silicon and germanium. However, interconnecting larger numbers of qubits in...article 2021
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van Riggelen, F (author), Hendrickx, N.W. (author), Lawrie, W.I.L. (author), Russ, M. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author)Quantum dots fabricated using techniques and materials that are compatible with semiconductor manufacturing are promising for quantum information processing. While great progress has been made toward high-fidelity control of quantum dots positioned in a linear arrangement, scalability along two dimensions is a key step toward practical quantum...conference paper 2021
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Aggarwal, K. (author), Hofmann, A. (author), Jirovec, D. (author), Prieto, I. (author), Sammak, A. (author), Botifoll, M. (author), Martí-Sánchez, S. (author), Veldhorst, M. (author), Arbiol, J. (author), Scappucci, G. (author), Danon, J. (author), Katsaros, G. (author)Hole gases in planar germanium can have high mobilities in combination with strong spin-orbit interaction and electrically tunable g factors, and are therefore emerging as a promising platform for creating hybrid superconductor-semiconductor devices. A key challenge towards hybrid Ge-based quantum technologies is the design of high-quality...article 2021
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Lawrie, W.I.L. (author), Eenink, H.G.J. (author), Hendrickx, N.W. (author), Boter, J.M. (author), Petit, L. (author), Amitonov, S.V. (author), Lodari, M. (author), paquelet Wuetz, B. (author), Volk, C. (author), Philips, S.G.J. (author), Droulers, G. (author), Kalhor, N. (author), van Riggelen, F. (author), Brousse, D. (author), Sammak, A. (author), Vandersypen, L.M.K. (author), Scappucci, G. (author), Veldhorst, M. (author)Electrons and holes confined in quantum dots define excellent building blocks for quantum emergence, simulation, and computation. Silicon and germanium are compatible with standard semiconductor manufacturing and contain stable isotopes with zero nuclear spin, thereby serving as excellent hosts for spins with long quantum coherence. Here, we...article 2020