A5040629029- Quantum Information and Cryptography
- Quantum and electron transport phenomena
- Quantum Computing Algorithms and Architecture
- Physics of Superconductivity and Magnetism
- Quantum optics and atomic interactions
- Quantum Mechanics and Applications
- Mechanical and Optical Resonators
- Topological Materials and Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Semiconductor Quantum Structures and Devices
- Atomic and Subatomic Physics Research
- Photonic and Optical Devices
- Neural Networks and Reservoir Computing
- Strong Light-Matter Interactions
- Surface and Thin Film Phenomena
- Particle accelerators and beam dynamics
- Quantum-Dot Cellular Automata
- Electronic and Structural Properties of Oxides
- stochastic dynamics and bifurcation
- Advanced Thermodynamics and Statistical Mechanics
- Statistical Mechanics and Entropy
- Corporate Taxation and Avoidance
- Superconductivity in MgB2 and Alloys
- Quantum many-body systems
- Advanced Fiber Laser Technologies
Delft University of Technology
2022-2025
Kavli Energy NanoScience Institute
2025
QuTech
2022-2024
Massachusetts General Hospital
2024
Harvard University
2024
ETH Zurich
2017-2023
Aarhus University
2012-2020
Université de Sherbrooke
2017-2020
Fast, high-fidelity readout of qubits is crucial in quantum computing. Quantum error correction particular requires the repeated measurement subsets without perturbing any others. Achieving this goal a multiplexed architecture has been challenging, mainly due to crosstalk signals. In work, individual Purcell filters are used for each resonator protect from untargeted signals, and radiative decay. By implementing scheme, which could find broad use near-term multiqubit devices, authors...
Quantum computing crucially relies on the ability to efficiently characterize quantum states output by hardware. Conventional methods which probe these through direct measurements and classically computed correlations become computationally expensive when increasing system size. neural networks tailored recognize specific features of combining unitary operations, feedforward promise require fewer tolerate errors. Here, we realize a convolutional network (QCNN) 7-qubit superconducting...
Andreev (or superconducting) spin qubits (ASQs) have recently emerged as a promising qubit platform that combines superconducting circuits with semiconductor degrees of freedom. While recent experiments successfully coupled two ASQs, how to realize scalable architecture for extending this coupling multiple distant remains an open question. In work, we resolve challenge by introducing achieves all-to-all connectivity between remote ASQs. Our approach enables selective any pair while keeping...
Quantum annealing aims to solve combinatorial optimization problems mapped on Ising interactions between quantum spins. A critical factor that limits the success of a annealer is its sensitivity noise, and intensive research consequently focussed towards developing noise-resilient annealers. Here we propose new paradigm for with scalable network all-to-all connected, two-photon driven Kerr-nonlinear resonators. Each these resonators encode an spin in robust degenerate subspace formed by two...
The strong coupling limit of cavity quantum electrodynamics (QED) implies the capability a matter-like system to coherently transform an individual excitation into single photon within resonant structure. This not only enables essential processes required for information processing but also allows fundamental studies matter-light interaction. In this work we demonstrate between charge degree freedom in gate-detuned GaAs double dot (DQD) and frequency-tunable high impedance resonator realized...
High fidelity two-qubit gates exhibiting low cross talk are essential building blocks for gate-based quantum information processing. In superconducting circuits, typically based either on rf-controlled interactions or the in situ tunability of qubit frequencies. Here, we present an alternative approach using a tunable cross-Kerr-type $ZZ$ interaction between two qubits, which realize with flux-tunable coupler element. We control $ZZ$-coupling rate over 3 orders magnitude to perform rapid (38...
Variational quantum algorithms are believed to be promising for solving computationally hard problems on noisy intermediate-scale (NISQ) systems. Gaining computational power from these critically relies the mitigation of errors during their execution, which coherence-limited operations is achievable by reducing gate count. Here, we demonstrate an improvement up a factor 3 in algorithmic performance approximate optimization algorithm (QAOA) as measured success probability, implementing...
We realize a hybrid superconductor-semiconductor transmon device in which the Josephson effect is controlled by gate-defined quantum dot an InAs/Al nanowire. Microwave spectroscopy of transmon's transition spectrum allows us to probe ground state parity as function gate voltages, external magnetic flux, and field applied parallel The measured phase diagram agreement with that predicted single-impurity Anderson model superconducting leads. Through continuous time monitoring circuit we...
We use a hybrid superconductor-semiconductor transmon device to perform spectroscopy of quantum dot Josephson junction tuned be in spin-1/2 ground state with an unpaired quasiparticle. Because spin-orbit coupling, we resolve two flux-sensitive branches the spectrum, depending on spin A finite magnetic field shifts energy, favoring one and resulting anomalous effect. demonstrate excitation direct spin-flip transition using all-electrical control. Manipulation control enable future...
Andreev bound states are fermionic localized in weak links between superconductors, which can be occupied with spinful quasiparticles. Recently, experiments embedding a nanowire Josephson junction into superconducting circuit have enabled coherent manipulation of single spin. However, these remained limited to small magnetic fields. Here, the authors measure microwave spectra fields up $\ensuremath{\sim}$ 250 mT and identify singlet, doublet, triplet interacting spins.
Reading out the state of a quantum system at low temperature is generally challenging, as weak signals must be amplified while adding little noise possible. Also, some qubit types rely on external magnetic fields and require magnetic-field-compatible superconducting parametric amplifiers. Here an innovative amp design leverages nonlinear response gate-tunable kinetic inductance proximitized semiconducting nanowires. The tunability allows integration with systems, thanks to minimal crosstalk,...
Feedback is a main component of many algorithms for quantum computing and communication. A key requirement any feedback scheme that the $l\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}y$ loop ($i.e.$ time between beginning to measure state end action on state) must be significantly shorter than coherence system. In this work superconducting qubit initialized in its ground by active feedback,...
A major challenge in operating multi-qubit quantum processors is to mitigate coherent errors. For superconducting circuits, besides crosstalk originating from imperfect isolation of control lines, dispersive coupling between qubits a source We benchmark phase errors controlled-phase gate due either the involved one or more spectator qubits. measure associated infidelity using process tomography. In addition, we point out that, non-computational state during gate, two-qubit conditional are...
Building a quantum computer is daunting challenge since it requires good control but also isolation from the environment to minimize decoherence. It therefore important realize gates efficiently, using as few operations possible, reduce amount of required and operation time thus improve state coherence. Here we propose superconducting circuit for implementing tunable system consisting qutrit coupled two qubits. This can efficiently accomplish various information tasks, including generation...
Fault tolerant quantum computing relies on the ability to detect and correct errors, which in error correction codes is typically achieved by projectively measuring multi-qubit parity operators conditioning operations observed syndromes. Here, we experimentally demonstrate use of an ancillary qubit repeatedly measure $ZZ$ $XX$ two data qubits thereby project their joint state into respective subspaces. By applying feedback conditioned outcomes individual measurements, real-time stabilization...
Quantum error correction will be an essential ingredient in realizing fault-tolerant quantum computing. However, most schemes rely on the assumption that errors are sufficiently uncorrelated space and time. In superconducting qubits, this is drastically violated presence of ionizing radiation, which creates bursts high-energy phonons substrate. These can break Cooper pairs superconductor and, thus, create quasiparticles over large areas, consequently reducing qubit coherence across device a...
Abstract Semiconductor qubits rely on the control of charge and spin degrees freedom electrons or holes confined in quantum dots. They constitute a promising approach to information processing, complementary superconducting qubits. Here, we demonstrate coherent coupling between transmon qubit semiconductor double dot (DQD) mediated by virtual microwave photon excitations tunable high-impedance SQUID array resonator acting as bus. The transmon-charge rate (~21 MHz) exceeds linewidth both...
We report the detection of a gate-tunable kinetic inductance in hybrid InAs/Al nanowire. For this purpose, we have embedded nanowire into quarter-wave coplanar waveguide resonator and measured resonance frequency circuit. find that can be changed via gate voltage controls electron density proximitized semiconductor thus inductance. Applying Mattis-Bardeen theory, extract dependence normal state conductivity nanowire, as well its superconducting gap. Our measurements complement existing...
Quantum information processing based on light has invigorated research the production and detection of single photons. The authors present an innovative scheme for weak microwave signals, a superconducting current-biased Josephson junction. In contrast to detectors that absorb photons, this system is optimized such amplitude classical photon field triggers detection.
We study an implementation of the open GRAPE (Gradient Ascent Pulse Engineering) algorithm well suited for large quantum systems. While typical implementations optimal control algorithms systems rely on explicit matrix exponential calculations, our avoids these operations leading to a polynomial speed-up in cases interest. This speed-up, as reduced memory requirements implementation, are illustrated by comparison standard GRAPE. As practical example, we apply this open-system optimization...