A5028014163- Quantum and electron transport phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- Quantum Computing Algorithms and Architecture
- Quantum Information and Cryptography
- Surface and Thin Film Phenomena
- Quantum-Dot Cellular Automata
- Photonic and Optical Devices
- Nanowire Synthesis and Applications
- Topological Materials and Phenomena
- Electronic and Structural Properties of Oxides
- Physics of Superconductivity and Magnetism
- Magnetic properties of thin films
- Mechanical and Optical Resonators
- Semiconductor materials and interfaces
- Force Microscopy Techniques and Applications
- Advanced Materials Characterization Techniques
- Silicon Nanostructures and Photoluminescence
- Silicon and Solar Cell Technologies
- Semiconductor Lasers and Optical Devices
- Water Quality Monitoring and Analysis
- Advanced Data Storage Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Diamond and Carbon-based Materials Research
Delft University of Technology
2016-2025
QuTech
2016-2025
Kavli Energy NanoScience Institute
2022-2024
Kavli Institute for Theoretical Sciences
2018-2020
Intel (United States)
2019
UNSW Sydney
2008-2017
Centre for Quantum Computation and Communication Technology
2008-2017
Australian Research Council
2007-2014
Quantum (Australia)
2014
Roma Tre University
2001-2007
High-fidelity control of quantum bits is paramount for the reliable execution algorithms and achieving fault-tolerance, ability to correct errors faster than they occur. The central requirement fault-tolerance expressed in terms an error threshold. Whereas actual threshold depends on many details, a common target ~1% well-known surface code. Reaching two-qubit gate fidelities above 99% has been long-standing major goal semiconductor spin qubits. These qubits are well positioned scaling as...
We report the strong coupling of a single electron spin and microwave photon. The is trapped in silicon double quantum dot photon stored an on-chip high-impedance superconducting resonator. electric field component cavity couples directly to charge dipole dot, indirectly spin, through local magnetic gradient from nearby micromagnet. This result opens way realization large networks based qubit registers, removing major roadblock scalable computing with qubits.
Future quantum computers capable of solving relevant problems will require a large number qubits that can be operated reliably. However, the requirements having qubit count and operating with high-fidelity are typically conflicting. Spins in semiconductor dots show long-term promise but demonstrations so far use between one four optimize fidelity either single- or two-qubit operations, initialization readout. Here we increase simultaneously achieve respectable fidelities for universal...
Full-scale quantum computers require the integration of millions bits. The promise leveraging industrial semiconductor manufacturing to meet this requirement has fueled pursuit computing in silicon dots. However, date, their fabrication relied on electron-beam lithography and, with few exceptions, academic style lift-off processes. Although these techniques offer process flexibility, they suffer from low yield and poor uniformity. An important question is whether processing conditions...
Abstract The efficient control of a large number qubits is one the most challenging aspects for practical quantum computing. Current approaches in solid-state technology are based on brute-force methods, where each and every qubit requires at least unique line—an approach that will become unsustainable when scaling to required millions qubits. Here, inspired by random-access architectures classical electronics, we introduce shared semiconductor dots efficiently operate two-dimensional...
We report the coherent coupling of two electron spins at a distance via virtual microwave photons. Each spin is trapped in silicon double quantum dot either end superconducting resonator, achieving spin-photon couplings up to around gs/2π=40 MHz. As are brought into resonance with each other, but detuned from photons, an avoided crossing larger than linewidths observed exchange splitting 2J/2π=20 In addition, photon-number states resolved shift 2χs/2π=−13 MHz that they induce on frequency....
Charge noise in the host semiconductor degrades performance of spin-qubits and poses an obstacle to control large quantum processors. However, it is challenging engineer heterogeneous material stack gate-defined dots improve charge systematically. Here, we address semiconductor-dielectric interface buried well a 28Si/SiGe heterostructure show connection between noise, measured locally dots, global disorder semiconductor, with macroscopic Hall bars. In 5 nm thick 28Si wells, find that...
Abstract Practical Quantum computing hinges on the ability to control large numbers of qubits with high fidelity. dots define a promising platform due their compatibility semiconductor manufacturing. Moreover, high-fidelity operations above 99.9% have been realized individual qubits, though performance has limited 98.67% when driving two simultaneously. Here we present single-qubit randomized benchmarking in two-dimensional array spin finding native gate fidelities as 99.992(1)%....
Qubits that can be efficiently controlled are essential for the development of scalable quantum hardware. Although resonant control is used to execute high-fidelity gates, scalability challenged by integration high-frequency oscillating signals, qubit cross-talk, and heating. Here, we show engineering hopping spins between dots with a site-dependent spin quantization axis, established discrete signals. We demonstrate hopping-based logic obtain single-qubit gate fidelities 99.97%, coherent...
Superconductors and semiconductors are crucial platforms in the field of quantum computing. They can be combined to hybrids, bringing together physical properties that enable discovery new emergent phenomena provide novel strategies for control. The involved semiconductor materials, however, suffer from disorder, hyperfine interactions or lack planar technology. Here we realise an approach overcomes these issues altogether integrate gate-defined dots superconductivity into germanium...
Buried-channel semiconductor heterostructures are an archetype material platform to fabricate gated quantum devices. Sharp confinement potential is obtained by positioning the channel near surface, however nearby surface states degrade electrical properties of starting material. In this paper we demonstrate a two-dimensional hole gas high mobility ($5\times 10^{5}$ cm$^2$/Vs) in very shallow strained germanium channel, which located only 22 nm below surface. This leads mean free paths...
Building a large-scale quantum computer requires the co-optimization of both bits (qubits) and their control electronics. By operating CMOS circuits at cryogenic temperatures (cryo-CMOS), hence in close proximity to solid-state qubits, compact quantum-computing system can be achieved, thus promising scalability large number qubits required practical application. This work presents cryo-CMOS microwave signal generator for frequency-multiplexed 4 × 32 (32 per RF output). A digitally intensive...
Quantum computers (QC), comprising qubits and a classical controller, can provide exponential speed-up in solving certain problems. Among solid-state qubits, transmons spin-qubits are the most promising, operating ≪ 1K. A qubit be implemented physical system with two distinct energy levels representing |0) |1) states, e.g. up down spin states of an electron. The manipulated microwave pulses, whose frequency f matches level spacing E = hf (Fig. 19.1.1). For transmons, ~ 6GHz, for 20GHz,...
Abstract Control of entanglement between qubits at distant quantum processors using a two-qubit gate is an essential function scalable, modular implementation computation. Among the many qubit platforms, spin in silicon dots are promising for large-scale integration along with their nanofabrication capability. However, linking challenging as gates typically utilize short-range exchange coupling, which only effective nearest-neighbor dots. Here we demonstrate via coherent shuttling, key...
Abstract Electron spins in Si/SiGe quantum wells suffer from nearly degenerate conduction band valleys, which compete with the spin degree of freedom formation qubits. Despite attempts to enhance valley energy splitting deterministically, by engineering a sharp interface, fluctuations remain serious problem for qubit uniformity, needed scale up large processors. Here, we elucidate and statistically predict holistic integration 3D atomic-level properties, theory transport. We find that...
The co-integration of spin, superconducting, and topological systems is emerging as an exciting pathway for scalable high-fidelity quantum information technology. High-mobility planar germanium a front-runner semiconductor building processors with spin-qubits, but progress hybrid superconductor-semiconductor devices hindered because obtaining superconducting gap free subgap states (hard gap) has proven difficult. Here we solve this challenge by developing low-disorder, oxide-free interface...
A strained Ge quantum well, grown on a SiGe/Si virtual substrate and hosting two electrostatically defined hole spin qubits, is nondestructively investigated by synchrotron-based scanning X-ray diffraction microscopy to determine all its Bravais lattice parameters. This allows rendering the three-dimensional spatial dependence of six strain tensor components with lateral resolution approximately 50 nm. Two different scales governing field fluctuations in proximity qubits are observed at <100...
Silicon/silicon-germanium heterostructures have many important advantages for hosting spin qubits. However, controlling the valley splitting (the energy between two low-lying conduction-band valleys) remains a critical challenge ensuring qubit reliability. Broad distributions of splittings are commonplace, even among quantum dots formed on same chip. In this work, we theoretically explore interplay quantum-well imperfections that suppress and cause variability, such as broadened interfaces...
Coherent links between qubits separated by tens of micrometers are expected to facilitate scalable quantum computing architectures for spin in electrically defined dots. These create space classical on-chip control electronics qubit arrays, which can help alleviate the so-called wiring bottleneck. A promising method achieving coherent distant consists shuttling through an array Here, we use a linear four tunnel-coupled dots 28Si/SiGe heterostructure short link. We move electron dot adjusting...