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Nondestructive readout for a superconducting flux qubit

Lupascu, A. (author), Verwijs, C.J.M. (author), Schouten, R.N. (author), Harmans, C.J.P.M. (author), Mooij, J.E. (author)

journal article 2004

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Real-time detection of single-electron tunneling using a quantum point contact

Vandersypen, L.M.K. (author), Elzerman, J.M. (author), Schouten, R.N. (author), Willems van Beveren, L.H. (author), Hanson, R. (author), Kouwenhoven, L.P. (author)

We observe individual tunnel events of a single electron between a quantum dot and a reservoir, using a nearby quantum point contact (QPC) as a charge meter. The QPC is capacitively coupled to the dot, and the QPC conductance changes by about 1% if the number of electrons on the dot changes by one. The QPC is voltage biased and the current is...

journal article 2004

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Low-frequency noise in Josephson junctions for superconducting qubits

Eroms, J. (author), Van Schaarenburg, L.C. (author), Driessen, E.F.C. (author), Plantenberg, J.H. (author), Huizinga, C.M. (author), Schouten, R.N. (author), Verbruggen, A.H. (author), Harmans, C.J.P.M. (author), Mooij, J.E. (author)

The authors have studied low-frequency resistance fluctuations in shadow-evaporated Al/AlOx/Al tunnel junctions. Between 300 and 5?K the spectral density follows a 1/f law. Below 5?K, individual defects distort the 1/f shape of the spectrum. The spectral density decreases linearly with temperature between 150 and 1?K and saturates below 0.8?K....

journal article 2006

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Cryogenic amplifier for fast real-time detection of single-electron tunneling

Vink, I.T. (author), Nooitgedagt, T. (author), Schouten, R.N. (author), Vandersypen, L.M.K. (author), Wegscheider, W. (author)

The authors employ a cryogenic high electron mobility transistor (HEMT) amplifier to increase the bandwidth of a charge detection setup with a quantum point contact (QPC) charge sensor. The HEMT is operating at 1?K and the circuit has a bandwidth of 1?MHz. The noise contribution of the HEMT at high frequencies is only a few times higher than...

journal article 2007

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Josephson squelch filter for quantum nanocircuits

Forn-Díaz, P. (author), Schouten, R.N. (author), Den Braver, W.A. (author), Mooij, J.E. (author), Harmans, C.J.P.M. (author)

We fabricated and tested a squelch circuit consisting of a copper powder filter with an embedded Josephson junction connected to ground. For small signals (squelch ON), the small junction inductance attenuates strongly from dc to at least 1 GHz, while for higher frequencies dissipation in the copper powder increases the attenuation exponentially...

journal article 2009

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Low-crosstalk bifurcation detectors for coupled flux qubits

De Groot, P.C. (author), Van Loo, A.F. (author), Lisenfeld, J. (author), Schouten, R.N. (author), Lupa?cu, A. (author), Harmans, C.J.P.M. (author), Mooij, J.E. (author)

We present experimental results on the crosstalk between two ac-operated dispersive bifurcation detectors, implemented in a circuit for high-fidelity readout of two strongly coupled flux qubits. Both phase-dependent and phase-independent contributions to the crosstalk are analyzed. For proper tuning of the phase the measured crosstalk is 0.1%...

journal article 2010

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Read-out of superconducting single photon detectors

Dorenbos, S.N. (author), Zwiller, V.G. (author), Schouten, R.N. (author)

Detection arrangement having an array of at least one superconducting single photon detector (SSPD). The detection arrangement further has a cryogenic part (9) with the array of at least one SSPD (1), the cryogenic part (9) being at a superconducting temperature in operation. Also, a separate charge storage element (5) in the form of an...

patent 2011

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Printed circuit board metal powder filters for low electron temperatures

Mueller, F. (author), Schouten, R.N. (author), Brauns, M. (author), Gang, T. (author), Lim, W.H. (author), Lai, N.S. (author), Dzurak, A.S. (author), Van der Wiel, W.G. (author), Zwanenburg, F.A. (author)

We report the characterisation of printed circuit boards (PCB) metal powder filters and their influence on the effective electron temperature which is as low as 22 mK for a quantum dot in a silicon MOSFET structure in a dilution refrigerator. We investigate the attenuation behaviour (10 MHz–20 GHz) of filter made of four metal powders with a...

journal article 2013

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Capacitive readout and gating of superconducting single photon detectors

Azzouz, H. (author), Heeres, R.W. (author), Dorenbos, S.N. (author), Schouten, R.N. (author), Zwiller, V. (author)

We propose and develop a readout scheme for superconducting single-photon detectors based on an integrated circuit, relaxing the need for large bandwidth amplification and resulting in voltage steps proportional to the number of detected photons. We also demonstrate time gating, to filter scattered light in time and reduce dark counts. This...

journal article 2013

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Millisecond charge-parity fluctuations and induced decoherence in a superconducting transmon qubit

Riste, D. (author), Bultink, C.C. (author), Tiggelman, M.J. (author), Schouten, R.N. (author), Lehnert, K.W. (author), DiCarlo, L. (author)

The tunnelling of quasiparticles across Josephson junctions in superconducting quantum circuits is an intrinsic decoherence mechanism for qubit degrees of freedom. Understanding the limits imposed by quasiparticle tunnelling on qubit relaxation and dephasing is of theoretical and experimental interest, particularly as improved understanding of...

journal article 2013

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Reversing Quantum Trajectories with Analog Feedback

De Lange, G. (author), Riste, D. (author), Tiggelman, M.J. (author), Eichler, C. (author), Tornberg, L. (author), Johansson, G. (author), Wallraff, A. (author), Schouten, R.N. (author), DiCarlo, L. (author)

We demonstrate the active suppression of transmon qubit dephasing induced by dispersive measurement, using parametric amplification and analog feedback. By real-time processing of the homodyne record, the feedback controller reverts the stochastic quantum phase kick imparted by the measurement on the qubit. The feedback operation matches a model...

journal article 2014

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Loophole-free Bell test using electron spins in diamond: Second experiment and additional analysis

Hensen, B.J. (author), Kalb, N. (author), Blok, M.S. (author), Dréau, A.E. (author), Reiserer, A.A. (author), Vermeulen, R.F.L. (author), Schouten, R.N. (author), Markham, M. (author), Twitchen, D.J. (author), Goodenough, K.D. (author), Elkouss Coronas, D. (author), Wehner, S.D.C. (author), Taminiau, T.H. (author), Hanson, R. (author)

The recently reported violation of a Bell inequality using entangled electronic spins in diamonds (Hensen et al., Nature 526, 682–686) provided the first loophole-free evidence against local-realist theories of nature. Here we report on data from a second Bell experiment using the same experimental<br/>setup with minor modifications. We find a...

journal article 2016

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Active Resonator Reset in the Nonlinear Dispersive Regime of Circuit QED

Bultink, C.C. (author), Rol, M.A. (author), O'Brien, T.E. (author), Fu, X. (author), Dikken, B.C.S. (author), Dickel, C. (author), Vermeulen, R.F.L. (author), de Sterke, J.C. (author), Bruno, A. (author), Schouten, R.N. (author), DiCarlo, L. (author)

We present two pulse schemes to actively deplete measurement photons from a readout resonator in the nonlinear dispersive regime of circuit QED. One method uses digital feedback conditioned on the measurement outcome, while the other is unconditional. In the absence of analytic forms and symmetries to exploit in this nonlinear regime, the...

journal article 2016

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Restless Tuneup of High-Fidelity Qubit Gates

Rol, M.A. (author), Bultink, C.C. (author), O'Brien, T.E. (author), De Jong, S. R. (author), Theis, L. S. (author), Fu, X. (author), Lüthi, F. (author), Vermeulen, R.F.L. (author), de Sterke, J.C. (author), Bruno, A. (author), Deurloo, D. (author), Schouten, R.N. (author), Wilhelm, FK (author), DiCarlo, L. (author)

We present a tuneup protocol for qubit gates with tenfold speedup over traditional methods reliant on qubit initialization by energy relaxation. This speedup is achieved by constructing a cost function for Nelder-Mead optimization from real-time correlation of nondemolition measurements interleaving gate operations without pause. Applying the...

journal article 2017

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An experimental microarchitecture for a superconducting qantum processor

Fu, X. (author), Rol, M.A. (author), Bultink, C.C. (author), van Someren, J. (author), Khammassi, N. (author), Ashraf, I. (author), Vermeulen, R.F.L. (author), de Sterke, J.C. (author), Vlothuizen, W.J. (author), Schouten, R.N. (author), Almudever, Carmen G. (author), DiCarlo, L. (author), Bertels, K.L.M. (author)

Quantum computers promise to solve certain problems that are intractable for classical computers, such as factoring large numbers and simulating quantum systems. To date, research in quantum computer engineering has focused primarily at opposite ends of the required system stack: devising high-level programming languages and compilers to...

conference paper 2017

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Probing DNA Translocations with Inplane Current Signals in a Graphene Nanoribbon with a Nanopore

Heerema, S.J. (author), Vicarelli, L. (author), Pud, S. (author), Schouten, R.N. (author), Zandbergen, H.W. (author), Dekker, C. (author)

Many theoretical studies predict that DNA sequencing should be feasible by monitoring the transverse current through a graphene nanoribbon while a DNA molecule translocates through a nanopore in that ribbon. Such a readout would benefit from the special transport properties of graphene, provide ultimate spatial resolution because of the single...

journal article 2018

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A Microarchitecture for a Superconducting Quantum Processor

Fu, X. (author), Rol, M.A. (author), Bultink, C.C. (author), van Someren, J. (author), Khammassi, N. (author), Ashraf, I. (author), Vermeulen, R.F.L. (author), de Sterke, J.C. (author), Vlothuizen, W.J. (author), Schouten, R.N. (author), Almudever, Carmen G. (author), DiCarlo, L. (author), Bertels, K.L.M. (author)

This article proposes a quantum microarchitecture, QuMA. Flexible programmability of a quantum processor is achieved by multilevel instructions decoding, abstracting analog control into digital control, and translating instruction execution with non-deterministic timing into event trigger with precise timing. QuMA is validated by several...

journal article 2018

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A capacitance spectroscopy-based platform for realizing gate-defined electronic lattices

Hensgens, T. (author), Mukhopadhyay, U. (author), Barthelemy, P.J.C. (author), Vermeulen, R.F.L. (author), Schouten, R.N. (author), Fallahi, S. (author), Gardner, G. C. (author), Reichl, C. (author), Wegscheider, W. (author), Manfra, M. J. (author), Vandersypen, L.M.K. (author)

Electrostatic confinement in semiconductors provides a flexible platform for the emulation of interacting electrons in a two-dimensional lattice, including in the presence of gauge fields. This combination offers the potential to realize a wide host of quantum phases. Capacitance spectroscopy provides a technique that allows one to directly...

journal article 2018

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Deterministic delivery of remote entanglement on a quantum network

Humphreys, P.C. (author), Kalb, N. (author), Morits, J.P.J. (author), Schouten, R.N. (author), Vermeulen, R.F.L. (author), Twitchen, Daniel J. (author), Markham, Matthew (author), Hanson, R. (author)

Large-scale quantum networks promise to enable secure communication, distributed quantum computing, enhanced sensing and fundamental tests of quantum mechanics through the distribution of entanglement across nodes ^1-7. Moving beyond current two-node networks ^8-13 requires the rate of entanglement generation between nodes...

journal article 2018

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Spin Lifetime and Charge Noise in Hot Silicon Quantum Dot Qubits

Petit, L. (author), Boter, J.M. (author), Eenink, H.G.J. (author), Droulers, G. (author), Tagliaferri, M.L.V. (author), Li, R. (author), Franke, D.P. (author), Singh, K. J. (author), Clarke, J. S. (author), Schouten, R.N. (author), Dobrovitski, V.V. (author), Vandersypen, L.M.K. (author), Veldhorst, M. (author)

We investigate the magnetic field and temperature dependence of the single-electron spin lifetime in silicon quantum dots and find a lifetime of 2.8 ms at a temperature of 1.1 K. We develop a model based on spin-valley mixing and find that Johnson noise and two-phonon processes limit relaxation at low and high temperature, respectively. We...

journal article 2018