A5007054325- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Semiconductor Quantum Structures and Devices
- Quantum Information and Cryptography
- Surface and Thin Film Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Photonic and Optical Devices
- Advancements in Semiconductor Devices and Circuit Design
- Electronic and Structural Properties of Oxides
- Graphene research and applications
- Mechanical and Optical Resonators
- Quantum optics and atomic interactions
- Advanced Semiconductor Detectors and Materials
- Atomic and Subatomic Physics Research
- Quantum many-body systems
- 2D Materials and Applications
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- Molecular Junctions and Nanostructures
- Quantum Mechanics and Applications
- Advanced Electrical Measurement Techniques
- Radio Frequency Integrated Circuit Design
- Semiconductor Lasers and Optical Devices
- Diamond and Carbon-based Materials Research
Delft University of Technology
2015-2025
QuTech
2017-2025
Microsoft (United States)
2023-2025
Microsoft (Netherlands)
2020-2024
ETH Zurich
2017-2022
VSL Dutch Metrology Institute
2010
We report the realization of quantum microwave circuits using hybrid superconductor-semiconductor Josephson elements comprised InAs nanowires contacted by NbTiN. Capacitively shunted single behave as transmon with electrically tunable transition frequencies. Two-element also exhibit transmonlike behavior near zero applied flux but qubits at half quantum, where nonsinusoidal current-phase relations in produce a double-well potential. These are promising for applications requiring...
Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They offered an exceptional testbed for superconductivity, leading the realization of hybrid systems combining macroscopic properties superconductors with possibility control charges down a single electron. These advances brought semiconductor forefront efforts realize topological superconductivity Majorana modes. A prime challenge benefit from...
The modern understanding of the Josephson effect in mesosopic devices derives from physics Andreev bound states, fermionic modes that are localized a superconducting weak link. Recently, junctions constructed using semiconducting nanowires have led to realization qubits with gate-tunable energies. We used microwave circuit QED architecture detect states such junction based on an aluminum-proximitized indium arsenide nanowire. demonstrate coherent manipulation these and track bound-state...
Quantum computation by non-Abelian Majorana zero modes (MZMs) offers an approach to achieve fault tolerance encoding quantum information in the non-local charge parity states of semiconductor nanowire networks topological superconductor regime. Thus far, experimental studies MZMs chiefly relied on single electron tunneling measurements which leads decoherence stored MZM. As a next step towards computation, conserving experiments based Josephson effect are required, can also help exclude...
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.
Topological superconductivity is a state of matter that can host Majorana modes, the building blocks topological quantum computer. Many experimental platforms predicted to show such rely on proximity-induced superconductivity. However, accessing properties requires an induced hard superconducting gap, which challenging achieve for most material systems. We have systematically studied how interface between InSb semiconductor nanowire and NbTiN superconductor affects properties. Step by step,...
We study the low-temperature electron mobility of InSb nanowires.We extract at 4.2 Kelvin by means field effect transport measurements using a model consisting nanowire-transistor with contact resistances.This enables an accurate extraction device parameters, thereby allowing for systematic nanowire mobility.We identify factors affecting mobility, and after optimization obtain ∼ 2.5 × 10 4 cm 2 /Vs.We further demonstrate reproducibility these values which are among highest reported...
Superconducting coplanar waveguide resonators that can operate in strong magnetic fields are important for a variety of high-frequency superconducting devices. Magnetic degrade resonator performance by creating Abrikosov vortices cause resistive losses and frequency fluctuations, or suppress the superconductivity entirely. To mitigate these effects, authors investigate how device geometry lithographically defined artificial defects control vortex dynamics. These techniques allow to retain...
Semiconductor quantum dots, where electrons or holes are isolated via electrostatic potentials generated by surface gates, promising building blocks for semiconductor-based technology. Here, we investigate double dot (DQD) charge qubits in GaAs, capacitively coupled to high-impedance SQUID array and Josephson junction resonators. We tune the strength of electric dipole interaction between qubit resonator in-situ using gates. characterize qubit-resonator coupling strength, decoherence,...
The realization of a coherent interface between distant charge or spin qubits in semiconductor quantum dots is an open challenge for information processing. Here, we demonstrate both resonant (real) and nonresonant (virtual) photon-mediated interactions double quantum-dot separated by several tens micrometers. We present clear spectroscopic evidence the collective enhancement coupling two resonator. With resonance with each other but detuned from resonator, observe exchange mediated virtual...
Developing fast and accurate control readout techniques is an important challenge in quantum information processing with semiconductor qubits. Here, we study the dynamics coherence properties of a GaAs/AlGaAs double dot (DQD) charge qubit strongly coupled to high-impedance SQUID array resonator. We drive transitions synthesized microwave pulses perform through state dependent frequency shift imparted by on dispersively Rabi oscillation, Ramsey fringe, energy relaxation Hahn-echo measurements...
Junctions created by coupling two superconductors via a semiconductor nanowire in the presence of high magnetic fields are basis for potential detection, fusion, and braiding Majorana bound states. We study $\mathrm{NbTiN}/\mathrm{InSb}$ $\text{nanowire}/\mathrm{NbTiN}$ Josephson junctions find that dependence critical current on field exhibits gate-tunable nodes. This is contrast with well-known Fraunhofer effect, under which nodes form regular pattern period fixed junction area. Based...
Circuit quantum electrodynamics, where photons are coherently coupled to artificial atoms built with superconducting circuits, has enabled the investigation and control of macroscopic quantum-mechanical phenomena in superconductors. Recently, hybrid circuits incorporating semiconducting nanowires other electrostatically-gateable elements have provided new insights into mesoscopic superconductivity. Extending capabilities flux-based work magnetic fields would be especially useful both as 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...
Semiconductor quantum dots, where electrons or holes are isolated via electrostatic potentials generated by surface gates, promising building blocks for semiconductor-based technology. Here, we investigate double dot (DQD) charge qubits in GaAs, capacitively coupled to high-impedance SQUID array and Josephson junction resonators. We tune the strength of electric dipole interaction between qubit resonator in-situ using gates. characterize qubit-resonator coupling strength, decoherence,...
We describe the automation of a pulse-driven AC Josephson voltage standard (ACJVS) that uses ternary arbitrary bitstream generator as bias source. A heuristic method called downhill simplex is used to find best operating parameters optimized for largest margins. Measurements are presented showing difference between manual and automated tuning. From these measurements we conclude tuning algorithm ACJVS working properly.
We measured the Josephson radiation emitted by an InSb semiconductor nanowire junction utilizing photon-assisted quasiparticle tunneling in ac-coupled superconducting tunnel junction. quantify action of local microwave environment evaluating frequency dependence inelastic Cooper-pair and find zero-frequency impedance $Z(0)=492\phantom{\rule{0.28em}{0ex}}\mathrm{\ensuremath{\Omega}}$ with a cutoff ${f}_{0}=33.1\phantom{\rule{0.28em}{0ex}}\mathrm{GHz}$. extract circuit coupling efficiency...
Andreev bound states are fermionic localized in weak links between superconductors which can be occupied with spinful quasiparticles. Microwave experiments using superconducting circuits InAs/Al nanowire Josephson junctions have recently enabled probing and coherent manipulation of but remained limited to zero or small fields. Here we use a flux-tunable circuit external magnetic fields up 1T perform spectroscopy spin-polarized ~250 mT, beyond the spectrum becomes gapless. We identify singlet...