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Corley-Wiciak, Cedric (author), Richter, Carsten (author), Zoellner, Marvin H. (author), Zaitsev, Ignatii (author), Manganelli, Costanza L. (author), Hendrickx, N.W. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, 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...journal article 2023
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Paquelet Wuetz, B. (author), Degli Esposti, D. (author), Zwerver, A.M.J. (author), Amitonov, S. (author), Botifoll, Marc (author), Arbiol, Jordi (author), Sammak, A. (author), Vandersypen, L.M.K. (author), Russ, M.F. (author), Scappucci, G. (author)Charge noise in the host semiconductor degrades the performance of spin-qubits and poses an obstacle to control large quantum processors. However, it is challenging to engineer the heterogeneous material stack of gate-defined quantum dots to improve charge noise systematically. Here, we address the semiconductor-dielectric interface and the...journal article 2023
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Bonsen, T.R. (author), Harvey-Collard, P. (author), Russ, M.F. (author), Dijkema, J.J. (author), Sammak, A. (author), Scappucci, G. (author), Vandersypen, L.M.K. (author)We report observations of transitions between excited states in the Jaynes-Cummings ladder of circuit quantum electrodynamics with electron spins (spin circuit QED). We show that unexplained features in recent experimental work correspond to such transitions and present an input-output framework that includes these effects. In new experiments...journal article 2023
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Meyer, M. (author), Déprez, C.C. (author), van Abswoude, Timo R. (author), Meijer, Ilja N. (author), Liu, Dingshan (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...journal article 2023
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Undseth, B.W. (author), Xue, X. (author), Mehmandoost, M. (author), Rimbach-Russ, Maximilian (author), Eendebak, P.T. (author), Samkharadze, Nodar (author), Sammak, A. (author), Dobrovitski, V.V. (author), Scappucci, G. (author), Vandersypen, L.M.K. (author)Micromagnet-based electric dipole spin resonance offers an attractive path for the near-term scaling of dense arrays of silicon spin qubits in gate-defined quantum dots while maintaining long coherence times and high control fidelities. However, accurately controlling dense arrays of qubits using a multiplexed drive will require an...journal article 2023
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Tosato, A. (author), Levajac, V. (author), Wang, J. (author), Boor, Casper J. (author), Borsoi, F. (author), Botifoll, Marc (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author)The co-integration of spin, superconducting, and topological systems is emerging as an exciting pathway for scalable and high-fidelity quantum information technology. High-mobility planar germanium is a front-runner semiconductor for building quantum processors with spin-qubits, but progress with hybrid superconductor-semiconductor devices is...journal article 2023
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Lawrie, W.I.L. (author), Russ, M.F. (author), van Riggelen, F. (author), Hendrickx, N.W. (author), de Snoo, S.L. (author), Sammak, A. (author), Scappucci, G. (author), Helsen, J. (author), Veldhorst, M. (author)Practical Quantum computing hinges on the ability to control large numbers of qubits with high fidelity. Quantum dots define a promising platform due to their compatibility with semiconductor manufacturing. Moreover, high-fidelity operations above 99.9% have been realized with individual qubits, though their performance has been limited to 98...journal article 2023
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Wang, C.A. (author), Déprez, C.C. (author), Tidjani, H. (author), Lawrie, W.I.L. (author), Hendrickx, N.W. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author)Simulations using highly tunable quantum systems may enable investigations of condensed matter systems beyond the capabilities of classical computers. Quantum dots and donors in semiconductor technology define a natural approach to implement quantum simulation. Several material platforms have been used to study interacting charge states,...journal article 2023
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Borsoi, F. (author), Hendrickx, N.W. (author), John, V. (author), Meyer, M. (author), Motz, Sayr (author), van Riggelen, F. (author), Sammak, A. (author), de Snoo, S.L. (author), Scappucci, G. (author), Veldhorst, M. (author)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...journal article 2023
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Stehouwer, L.E.A. (author), Tosato, A. (author), Degli Esposti, D. (author), Costa, D.C. (author), Veldhorst, M. (author), Sammak, A. (author), Scappucci, G. (author)We grow strained Ge/SiGe heterostructures by reduced-pressure chemical vapor deposition on 100 mm Ge wafers. The use of Ge wafers as substrates for epitaxy enables high-quality Ge-rich SiGe strain-relaxed buffers with a threading dislocation density of ( 6 ± 1 ) × 10 5 cm − 2 , nearly an order of magnitude improvement compared to control...journal article 2023
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Unseld, F.K. (author), Meyer, M. (author), Madzik, M.T. (author), Borsoi, F. (author), de Snoo, S.L. (author), Amitonov, S. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author), Vandersypen, L.M.K. (author)Semiconductor spin qubits have gained increasing attention as a possible platform to host a fault-tolerant quantum computer. First demonstrations of spin qubit arrays have been shown in a wide variety of semiconductor materials. The highest performance for spin qubit logic has been realized in silicon, but scaling silicon quantum dot arrays...journal article 2023
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Vermaas, P.E. (author), Wimmer, M.T. (author), Lomas, J.D. (author), Almudever, Carmen G. (author), Scappucci, G. (author)This magazine is both an introduction into quantum computing and an exploration of its impact on our world. It follows on from our 2019 magazine on the quantum internet. Since 2019, much progress has been made in quantum technologies worldwide. In 2020, for instance, the first European quantum computer came online in Delft. Although this is...report 2022
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Harvey-Collard, P. (author), Dijkema, J.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/2p=40 MHz. As the two spins are brought into resonance with each other, but detuned from the...journal article 2022
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Lodari, M. (author), Lampert, L. (author), Zietz, O. (author), Pillarisetty, R. (author), Clarke, J. S. (author), Scappucci, G. (author)We determine the energy splitting of the conduction-band valleys in two-dimensional electrons confined in silicon metal oxide semiconductor Hall-bar transistors. These silicon metal oxide semiconductor Hall bars are made by advanced semiconductor manufacturing on 300 mm silicon wafers and support a two-dimensional electron gas of high quality...journal article 2022
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Bavdaz, P.L. (author), Eenink, H.G.J. (author), van Staveren, J. (author), Lodari, M. (author), Almudever, C. G. (author), Clarke, J. S. (author), Sebastiano, F. (author), Veldhorst, M. (author), Scappucci, G. (author)We demonstrate a 36 × 36 gate electrode crossbar that supports 648 narrow-channel field effect transistors (FET) for gate-defined quantum dots, with a quadratic increase in quantum dot count upon a linear increase in control lines. The crossbar is fabricated on an industrial <sup>28</sup>Si-MOS stack and shows 100% FET yield at cryogenic...journal article 2022
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Koelling, Sebastian (author), Stehouwer, L.E.A. (author), Paquelet Wuetz, B. (author), Scappucci, G. (author), Moutanabbir, Oussama (author)Atom probes generate three-dimensional atomic-scale tomographies of material volumes corresponding to the size of modern-day solid-state devices. Here, the capabilities of atom probe tomography are evaluated to analyze buried interfaces in semiconductor heterostructures relevant for electronic and quantum devices. Employing brute-force search...journal article 2022
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Tosato, A. (author), Ferrari, B.M. (author), Sammak, A. (author), Hamilton, Alexander R. (author), Veldhorst, M. (author), Virgilio, Michele (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 (Formula presented.) and a low percolation density of ...journal 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 (ϵ / / = - 0.41 %) in an undoped Ge/Si0.1Ge0.9 heterostructure field effect transistor supports a two-dimensional (2D) hole gas with mobility in excess of 1 × 10 6 cm2/Vs and percolation density less than 5 × 10 10 cm-2. This low disorder 2D hole system shows tunable fractional quantum...journal article 2022
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Zwerver, A.M.J. (author), Krähenmann, T.S. (author), Amitonov, S. (author), Boter, J.M. (author), Droulers, G. (author), Lodari, M. (author), Samkharadze, Nodar (author), Zheng, G. (author), Scappucci, G. (author), Veldhorst, M. (author), Vandersypen, L.M.K. (author)Full-scale quantum computers require the integration of millions of qubits, and the potential of using industrial semiconductor manufacturing to meet this need has driven the development of quantum computing in silicon quantum dots. However, fabrication has so far relied on electron-beam lithography and, with a few exceptions, conventional...journal article 2022
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Xue, X. (author), Russ, M.F. (author), Samkharadze, Nodar (author), Undseth, B.W. (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<sup>1</sup>. The central requirement for fault tolerance is expressed in terms of an error threshold. Whereas the actual threshold depends on many details, a...journal article 2022