- document
-
van Cranenburgh, S. (author), Kouwenhoven, M.L.A. (author)This study proposes a novel Artificial Neural Network (ANN) based method to derive the Value-of-Travel-Time (VTT) distribution. The strength of this method is that it is possible to uncover the VTT distribution (and its moments) without making assumptions about the shape of the distribution or the error terms, while being able to incorporate...journal article 2020
- document
-
Laroche, D. (author), Bouman, D. (author), van Woerkom, D.J. (author), Proutski, A. (author), Murthy, Chaitanya (author), Nayak, Chetan (author), van Gulik, R.J.J. (author), Kouwenhoven, Leo P. (author), Geresdi, A. (author)Quantum computation by non-Abelian Majorana zero modes (MZMs) offers an approach to achieve fault tolerance by encoding quantum information in the non-local charge parity states of semiconductor nanowire networks in the topological superconductor regime. Thus far, experimental studies of MZMs chiefly relied on single electron tunneling...journal article 2019
- document
-
de Jong, D. (author), van Veen, J. (author), Binci, L. (author), Singh, A. (author), Krogstrup, P. (author), Kouwenhoven, Leo P. (author), Pfaff, W. (author), Watson, J.D. (author)Dispersive sensing is a powerful technique that enables scalable and high-fidelity readout of solid-state quantum bits. In particular, gate-based dispersive sensing has been proposed as the readout mechanism for future topological qubits, which can be measured by single electrons tunneling through zero-energy modes. The development of such a...journal article 2019
- document
-
Hendrickx, N.W. (author), Tagliaferri, M.L.V. (author), Kouwenhoven, M. (author), Li, R. (author), Franke, D.P. (author), Sammak, A. (author), Brinkman, A. (author), Scappucci, G. (author), Veldhorst, M. (author)We fabricate Josephson field-effect transistors in germanium quantum wells contacted by superconducting aluminum and demonstrate supercurrents carried by holes that extend over junction lengths of several micrometers. In superconducting quantum point contacts we observe discretization of supercurrent, as well as Fabry-Pérot resonances,...journal article 2019
- document
-
Bommer, J.D.S. (author), Zhang, Hao (author), Gül, Önder (author), Nijholt, B. (author), Wimmer, M.T. (author), Rybakov, Filipp N. (author), Garaud, Julien (author), Car, Diana (author), Plissard, Sébastien R. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, Leo P. (author)Spin-orbit interaction (SOI) plays a key role in creating Majorana zero modes in semiconductor nanowires proximity coupled to a superconductor. We track the evolution of the induced superconducting gap in InSb nanowires coupled to a NbTiN superconductor in a large range of magnetic field strengths and orientations. Based on realistic...journal article 2019
- document
-
Proutski, A. (author), Laroche, D. (author), Van 'T Hooft, Bas (author), Krogstrup, Peter (author), Nygård, Jesper (author), Kouwenhoven, Leo P. (author), Geresdi, A. (author)The Cooper-pair transistor (CPT), a small superconducting island enclosed between two Josephson weak links, is the atomic building block of various superconducting quantum circuits. Utilizing gate-tunable semiconductor channels as weak links, the energy scale associated with the Josephson tunneling can be changed with respect to the charging...journal article 2019
- document
-
Kroll, J. (author), Borsoi, F. (author), van der Enden, K.L. (author), Uilhoorn, W. (author), de Jong, D. (author), Quintero Perez, M. (author), van Woerkom, D.J. (author), Bruno, A. (author), Plissard, S. R. (author), Car, D. (author), Bakkers, E.P.A.M. (author), Cassidy, M.C. (author), Kouwenhoven, Leo P. (author)Superconducting coplanar-waveguide resonators that can operate in strong magnetic fields are important tools for a variety of high-frequency superconducting devices. Magnetic fields degrade resonator performance by creating Abrikosov vortices that cause resistive losses and frequency fluctuations or suppress the superconductivity entirely. To...journal article 2019
- document
-
Lee, Joon Sue (author), Koelling, Sebastian (author), Verheijen, Marcel A. (author), Petkovic, Ivana (author), Schaller, V. (author), Marcus, Charles M. (author), Krogstrup, Peter (author), Kouwenhoven, Leo P. (author), Bakkers, E.P.A.M. (author)We report on the selective-area chemical beam epitaxial growth of InAs in-plane, one-dimensional (1D) channels using patterned SiO2-coated InP(001), InP(111)B, and InP(011) substrates to establish a scalable platform for topological superconductor networks. Top-view scanning electron micrographs show excellent surface selectivity and...journal article 2019
- document
-
Aseev, P. (author), Fursina, A. (author), Boekhout, F. (author), Borsoi, F. (author), Heedt, S. (author), Wang, Guanzhong (author), Binci, L. (author), Koops, R. (author), Uccelli, E. (author), Kouwenhoven, Leo P. (author), Caroff-Gaonac'h, P. (author)Selective-area growth is a promising technique for enabling of the fabrication of the scalable III-V nanowire networks required to test proposals for Majorana-based quantum computing devices. However, the contours of the growth parameter window resulting in selective growth remain undefined. Herein, we present a set of experimental techniques...journal article 2019
- document
-
de Vries, F.K. (author), Sol, M.L. (author), Gazibegovic, S. (author), op het Veld, R.L.M. (author), Balk, S.C. (author), Car, D. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, Leo P. (author), Shen, J. (author)We study superconducting quantum interference in InSb flake Josephson junctions. An even-odd effect in the amplitude and periodicity of the superconducting quantum interference pattern is found. Interestingly, the occurrence of this pattern coincides with enhanced conduction at both edges of the flake, as is deduced from measuring a...journal article 2019
- document
-
van Veen, J. (author), de Jong, D. (author), Han, L. (author), Prosko, C.G. (author), Krogstrup, P. (author), Watson, J.D. (author), Kouwenhoven, Leo P. (author), Pfaff, W. (author)We report direct detection of charge tunneling between a quantum dot and a superconducting island through radio-frequency gate sensing. We are able to resolve spin-dependent quasiparticle tunneling as well as two-particle tunneling involving Cooper pairs. The quantum dot can act as an RF-only sensor to characterize the superconductor addition...journal article 2019
- document
-
Hendrickx, N.W. (author), Franke, D.P. (author), Sammak, A. (author), Kouwenhoven, M. (author), Sabbagh, D. (author), Yeoh, L.A. (author), Li, R. (author), Tagliaferri, M.L.V. (author), Virgilio, M. (author), Capellini, G. (author), Scappucci, G. (author), Veldhorst, M. (author)Superconductors and semiconductors are crucial platforms in the field of quantum computing. They can be combined to hybrids, bringing together physical properties that enable the discovery of new emergent phenomena and provide novel strategies for quantum control. The involved semiconductor materials, however, suffer from disorder, hyperfine...journal article 2018
- document
-
Zhang, H. (author), Liu, Chun Xiao (author), Gazibegovic, S. (author), Xu, D. (author), Logan, John A. (author), Wang, Guanzhong (author), van Loo, N. (author), Bommer, J.D.S. (author), de Moor, M.W.A. (author), Car, D. (author), op het Veld, R.L.M. (author), Van Veldhoven, Petrus J. (author), Kölling, S. (author), Verheijen, M.P.A.M. (author), Pendharkar, Mihir (author), Pennachio, Daniel J. (author), Shojaei, Borzoyeh (author), Lee, Joon Sue (author), Palmstrøm, Chris J. (author), Bakkers, E.P.A.M. (author), Sarma, S. Das (author), Kouwenhoven, Leo P. (author)Majorana zero-modes - a type of localized quasiparticle - hold great promise for topological quantum computing. Tunnelling spectroscopy in electrical transport is the primary tool for identifying the presence of Majorana zero-modes, for instance as a zero-bias peak in differential conductance. The height of the Majorana zero-bias peak is...journal article 2018
- document
-
de Vries, F.K. (author), Timmerman, Tom (author), Ostroukh, Viacheslav P. (author), van Veen, J. (author), Beukman, A.J.A. (author), Qu, F. (author), Wimmer, M.T. (author), Kiselev, Andrey A. (author), Kouwenhoven, Leo P. (author)Josephson junctions defined in strong spin orbit semiconductors are highly interesting for the search for topological systems. However, next to topological edge states that emerge in a sufficient magnetic field, trivial edge states can also occur. We study the trivial edge states with superconducting quantum interference measurements on...journal article 2018
- document
-
de Moor, M.W.A. (author), Bommer, J.D.S. (author), Xu, D. (author), Winkler, Georg W. (author), Antipov, Andrey E. (author), Bargerbos, A. (author), Wang, Guanzhong (author), van Loo, N. (author), op het Veld, R.L.M. (author), Gazibegovic, S. (author), Car, D. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, Leo P. (author), Zhang, H. (author)We study the effect of external electric fields on superconductor-semiconductor coupling by measuring the electron transport in InSb semiconductor nanowires coupled to an epitaxially grown Al superconductor. We find that the gate voltage induced electric fields can greatly modify the coupling strength, which has consequences for the proximity...journal article 2018
- document
-
Kouwenhoven, M.L.A. (author), de Jong, Gerard (author)The value of travel time can theoretically be defined as the opportunity cost of travel minus the direct utility from spending the time during the trip. This paper searches for empirical evidence to support this formulation. We show that travellers who indicate that a shorter trip duration is useful or a longer trip duration is very...journal article 2018
- document
-
van Veen, J. (author), Proutski, A. (author), Karzig, Torsten (author), Pikulin, D. (author), Lutchyn, Roman M. (author), Nygård, Jesper (author), Krogstrup, P. (author), Geresdi, A. (author), Kouwenhoven, Leo P. (author), Watson, J.D. (author)Parity control of superconducting islands hosting Majorana zero modes (MZMs) is required to operate topological qubits made from proximitized semiconductor nanowires. We test this control by studying parity effects in hybrid InAs-Al single-Cooper-pair transistors (SCPTs) to evaluate the feasibility of this material system. In particular, we...journal article 2018
- document
-
Kroll, J. (author), Uilhoorn, W. (author), van der Enden, K.L. (author), de Jong, D. (author), Watanabe, K. (author), Taniguchi, T. (author), Goswami, S. (author), Cassidy, M.C. (author), Kouwenhoven, Leo P. (author)Circuit quantum electrodynamics has proven to be a powerful tool to probe mesoscopic effects in hybrid systems and is used in several quantum computing (QC) proposals that require a transmon qubit able to operate in strong magnetic fields. To address this we integrate monolayer graphene Josephson junctions into microwave frequency...journal article 2018
- document
-
Shen, J. (author), Heedt, S. (author), Borsoi, F. (author), van Heck, B. (author), Gazibegovic, S. (author), op het Veld, R.L.M. (author), Car, D. (author), Ramakers, S.J.J. (author), Wang, Guanzhong (author), Xu, D. (author), Bouman, D. (author), Geresdi, A. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, Leo P. (author)The number of electrons in small metallic or semiconducting islands is quantised. When tunnelling is enabled via opaque barriers this number can change by an integer. In superconductors the addition is in units of two electron charges (2e), reflecting that the Cooper pair condensate must have an even parity. This ground state (GS) is...journal article 2018
- document
-
de Vries, F.K. (author), Shen, J. (author), Skolasinski, R.J. (author), Nowak, M.P. (author), Varjas, D. (author), Wang, L. (author), Wimmer, M.T. (author), Zwanenburg, F.A. (author), Li, A. (author), Kölling, S. (author), Verheijen, M.P.A.M. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, Leo P. (author)Low dimensional semiconducting structures with strong spin-orbit interaction (SOI) and induced superconductivity attracted great interest in the search for topological superconductors. Both the strong SOI and hard superconducting gap are directly related to the topological protection of the predicted Majorana bound states. Here we explore the...journal article 2018