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Practical strategies for enhancing the valley splitting in Si/SiGe quantum wells

Losert, Merritt P. (author), Eriksson, M. A. (author), Joynt, Robert (author), Rahman, Rajib (author), Scappucci, G. (author), Coppersmith, Susan N. (author), Friesen, Mark (author)

Silicon/silicon-germanium heterostructures have many important advantages for hosting spin qubits. However, controlling the valley splitting (the energy splitting between the two low-lying conduction-band valleys) remains a critical challenge for ensuring qubit reliability. Broad distributions of valley splittings are commonplace, even among...

journal article 2023

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Radio-Frequency Reflectometry in Silicon-Based Quantum Dots

Liu, Y. Y. (author), Philips, S.G.J. (author), Orona, L. A. (author), Samkharadze, Nodar (author), McJunkin, T. (author), Macquarrie, E. R. (author), Eriksson, M. A. (author), Vandersypen, L.M.K. (author), Yacoby, A. (author)

Radio-frequency (rf) reflectometry offers a fast and sensitive method for charge sensing and spin readout in gated quantum dots. We focus in this work on the implementation of rf readout in accumulation-mode gate-defined quantum dots, where the large parasitic capacitance poses a challenge. We describe and test two methods for mitigating the...

journal article 2021

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Looking backward to the future: On past-facing approaches to futuring

Bendor, R. (author), Eriksson, Elina (author), Pargman, Daniel (author)

While the past is present in all futuring activities it tends to remain implicit and has not received adequate attention by futures scholars and practitioners. In response, this conceptual paper offers a novel framework with which the past can be brought into futures studies in a structured and comprehensive way. We begin by providing a brief...

journal article 2021

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Majorana bound states in nanowire-superconductor hybrid systems in periodic magnetic fields

Kornich, V. (author), Vavilov, Maxim G. (author), Friesen, Mark (author), Eriksson, M. A. (author), Coppersmith, S. N. (author)

We study how the shape of a periodic magnetic field affects the presence of Majorana bound states (MBS) in a nanowire-superconductor system. Motivated by the field configurations that can be produced by an array of nanomagnets, we consider spiral fields with an elliptic cross section and fields with two sinusoidal components. We show that MBS...

journal article 2020

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Spatial noise correlations in a Si/SiGe two-qubit device from Bell state coherences

Boter, J.M. (author), Xue, X. (author), Krähenmann, T.S. (author), Watson, T.F. (author), Premakumar, Vickram N. (author), Ward, Daniel R. (author), Savage, Donald E. (author), Eriksson, Mark A. (author), Vandersypen, L.M.K. (author)

We study spatial noise correlations in a Si/SiGe two-qubit device with integrated micromagnets. Our method relies on the concept of decoherence-free subspaces, whereby we measure the coherence time for two different Bell states, designed to be sensitive only to either correlated or anticorrelated noise, respectively. From these measurements...

journal article 2020

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Tools for BIM-GIS Integration (IFC Georeferencing and Conversions): Results from the GeoBIM Benchmark 2019

Noardo, F. (author), Harrie, Lars (author), Arroyo Ohori, G.A.K. (author), Biljecki, F. (author), Ellul, Claire (author), Krijnen, T.F. (author), Eriksson, Helen (author), Guler, Dogus (author), Hintz, Dean (author), Stoter, J.E. (author)

The integration of 3D city models with Building Information Models (BIM), coined as GeoBIM, facilitates improved data support to several applications, e.g., 3D map updates, building permits issuing, detailed city analysis, infrastructure design, context-based building design, to name a few. To solve the integration, several issues need to be...

journal article 2020

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Repetitive Quantum Nondemolition Measurement and Soft Decoding of a Silicon Spin Qubit

Xue, X. (author), D'anjou, Benjamin (author), Watson, T.F. (author), Ward, Daniel R. (author), Savage, Donald E. (author), Lagally, Max G. (author), Friesen, Mark (author), Eriksson, Mark A. (author), Vandersypen, L.M.K. (author)

Quantum error correction is of crucial importance for fault-tolerant quantum computers. As an essential step toward the implementation of quantum error-correcting codes, quantum nondemolition measurements are needed to efficiently detect the state of a logical qubit without destroying it. Here we implement quantum nondemolition measurements...

journal article 2020

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Rolling out the red (and green) carpet: Supporting driver decision making in automation-to-manual transitions

Eriksson, Alexander (author), Petermeijer, S.M. (author), Zimmermann, Markus (author), de Winter, J.C.F. (author), Bengler, Klaus J. (author), Stanton, Neville A. (author)

This paper assessed four types of human–machine interfaces (HMIs), classified according to the stages of automation proposed by Parasuraman et al. [“A model for types and levels of human interaction with automation,” IEEE Trans. Syst. Man, Cybern. A, Syst. Humans, vol. 30, no. 3, pp. 286–297, May 2000]. We hypothesized that drivers would...

journal article 2019

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How to keep drivers engaged while supervising driving automation? A literature survey and categorisation of six solution areas

Cabrall, C.D.D. (author), Eriksson, Alexander (author), Dreger, F.A. (author), Happee, R. (author), de Winter, J.C.F. (author)

This work aimed to organise recommendations for keeping people engaged during human supervision of driving automation, encouraging a safe and acceptable introduction of automated driving systems. First, heuristic knowledge of human factors, ergonomics, and psychological theory was used to propose solution areas to human supervisory control...

journal article 2019

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Benchmarking Gate Fidelities in a Si/SiGe Two-Qubit Device

Xue, X. (author), Watson, T.F. (author), Helsen, J. (author), Ward, D. R. (author), Savage, D. E. (author), Lagally, M. G. (author), Coppersmith, S. N. (author), Eriksson, M. A. (author), Wehner, S.D.C. (author), Vandersypen, L.M.K. (author)

We report the first complete characterization of single-qubit and two-qubit gate fidelities in silicon-based spin qubits, including cross talk and error correlations between the two qubits. To do so, we use a combination of standard randomized benchmarking and a recently introduced method called character randomized benchmarking, which allows...

journal article 2019

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The critical role of substrate disorder in valley splitting in Si quantum wells

Neyens, Samuel F. (author), Foote, Ryan H. (author), Thorgrimsson, Brandur (author), Knapp, T. J. (author), McJunkin, Thomas (author), Vandersypen, L.M.K. (author), Amin, Payam (author), Thomas, Nicole K. (author), Clarke, James S. (author), Savage, D. E. (author), Lagally, M. G. (author), Friesen, Mark (author), Coppersmith, S. N. (author), Eriksson, M. A. (author)

Atomic-scale disorder at the top interface of a Si quantum well is known to suppress valley splitting. Such disorder may be inherited from the underlying substrate and relaxed buffer growth, but can also arise at the top quantum well interface due to the random SiGe alloy. Here, we perform activation energy (transport) measurements in the...

journal article 2018

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A programmable two-qubit quantum processor in silicon

Watson, T.F. (author), Philips, S.G.J. (author), Kawakami, E. (author), Ward, D. R. (author), Scarlino, P. (author), Veldhorst, M. (author), Savage, D. E. (author), Lagally, M. G. (author), Friesen, Mark (author), Coppersmith, S. N. (author), Eriksson, M.A. (author), Vandersypen, L.M.K. (author)

Now that it is possible to achieve measurement and control fidelities for individual quantum bits (qubits) above the threshold for fault tolerance, attention is moving towards the difficult task of scaling up the number of physical qubits to the large numbers that are needed for fault-tolerant quantum computing. In this context, quantum-dot...

journal article 2018

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A toolbox for automated driving on the STISIM driving simulator

Eriksson, A. (author), de Winter, J.C.F. (author), Stanton, Neville A. (author)

Driving simulators have been used since the beginning of the 1930s to assist researchers in assessing driver behaviour without putting the driver in harm’s way. The current manuscript describes the implementation of a toolbox for automated driving research on the widely used STISIM platform. The toolbox presented in this manuscript allows...

journal article 2018

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Topological transconductance quantization in a four-terminal Josephson junction

Eriksson, Erik (author), Riwar, Roman Pascal (author), Houzet, Manuel (author), Meyer, Julia S. (author), Nazarov, Y.V. (author)

Recently we predicted that the Andreev bound-state spectrum of four-terminal Josephson junctions may possess topologically protected zero-energy Weyl singularities, which manifest themselves in a quantized transconductance in units of 4e2/h when two of the terminals are voltage biased [R.-P. Riwar, M. Houzet, J. S. Meyer, and Y. V. Nazarov,...

journal article 2017

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Effect of waves on cavitation and pressure pulses of a tanker with twin podded propulsion

Taskar, Bhushan (author), Steen, Sverre (author), Eriksson, Jonas (author)

journal article 2017

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On the phase stability of CaCu₅-type compounds

Boeije, M.F.J. (author), Delczeg-Czirjak, E. K. (author), van Dijk, N.H. (author), Eriksson, O. (author), Brück, E.H. (author)

We present a hybrid method to inspect the phase stability of compounds having a CaCu₅-type crystal structure. This is done using 2D stability plots using the Miedema parameters that are based on the work function and electron density of the constituent elements. Stable compounds are separated from unstable binary compounds, with a...

journal article 2017

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Gate fidelity and coherence of an electron spin in an Si/SiGe quantum dot with micromagnet

Kawakami, E. (author), Jullien, T.M.J. (author), Scarlino, P. (author), Ward, Daniel R. (author), Savage, Donald E. (author), Lagally, Max G. (author), Dobrovitski, V.V. (author), Friesen, Mark (author), Coppersmith, Susan N. (author), Eriksson, M.A. (author), Vandersypen, L.M.K. (author)

The gate fidelity and the coherence time of a quantum bit (qubit) are important benchmarks for quantum computation. We construct a qubit using a single electron spin in an Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field from a micromagnet. We measure an average single-qubit gate fidelity of ∼99% using...

journal article 2016

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Second-Harmonic Coherent Driving of a Spin Qubit in a Si/SiGe Quantum Dot

Scarlino, P. (author), Kawakami, E. (author), Ward, D.R. (author), Savage, D.E. (author), Lagally, M.G. (author), Friesen, M. (author), Coppersmith, S.N. (author), Eriksson, M.A. (author), Vandersypen, L.M.K. (author)

We demonstrate coherent driving of a single electron spin using second-harmonic excitation in a Si/SiGe quantum dot. Our estimates suggest that the anharmonic dot confining potential combined with a gradient in the transverse magnetic field dominates the second-harmonic response. As expected, the Rabi frequency depends quadratically on the...

journal article 2015

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Silicon quantum electronics

Zwanenburg, F.A. (author), Dzurak, A.S. (author), Morello, A. (author), Simmons, M.Y. (author), Hollenberg, L.C.L. (author), Klimeck, G. (author), Rogge, S. (author), Coppersmith, S.N. (author), Eriksson, M.A. (author)

This review describes recent groundbreaking results in Si, Si/SiGe, and dopant-based quantum dots, and it highlights the remarkable advances in Si-based quantum physics that have occurred in the past few years. This progress has been possible thanks to materials development of Si quantum devices, and the physical understanding of quantum effects...

journal article 2013

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Single-Shot Readout of Singlet-Triplet Qubit States in a Si/SiGe Double Quantum Dot

Prance, J.R. (author), Shi, Z. (author), Siimins, C.B. (author), Savage, D.E. (author), Lagally, M.G. (author), Schreiber, L.R. (author), Vandersypen, L.M.K. (author), Friesen, M. (author), Joynt, R. (author), Coppersmith, S.N. (author), Eriksson, M.A. (author)

The spin singlet and triplet states of a two-electron double quantum dot can be used to form a logical qubit that combines fast manipulation and a spin readout mechanism. We demonstrate single-shot readout of the two-electron states of a Si/SiGe double quantum dot using a quantum-point-contact charge sensor and spin-to-charge conversion. From...

journal article 2012