A5082603133- Semiconductor Quantum Structures and Devices
- Quantum and electron transport phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and devices
- Integrated Circuits and Semiconductor Failure Analysis
- Silicon Nanostructures and Photoluminescence
- Photonic and Optical Devices
- Physics of Superconductivity and Magnetism
- Semiconductor materials and interfaces
- Explainable Artificial Intelligence (XAI)
- Quantum-Dot Cellular Automata
- Quantum Information and Cryptography
- Advanced Thermodynamics and Statistical Mechanics
- Spectroscopy and Quantum Chemical Studies
- Particle accelerators and beam dynamics
- Data Visualization and Analytics
- Surface and Thin Film Phenomena
- Computational Physics and Python Applications
- Neural Networks and Applications
- Quantum Computing Algorithms and Architecture
- Electronic and Structural Properties of Oxides
- ECG Monitoring and Analysis
- Topological and Geometric Data Analysis
- Quantum Dots Synthesis And Properties
- Anomaly Detection Techniques and Applications
University of Wisconsin–Madison
2019-2024
UNSW Sydney
2023
University of Manchester
2012
Abstract Large-scale arrays of quantum-dot spin qubits in Si/SiGe quantum wells require large or tunable energy splittings the valley states associated with degenerate conduction band minima. Existing proposals to deterministically enhance splitting rely on sharp interfaces modifications well barriers that can be difficult grow. Here, we propose and demonstrate a new heterostructure, “Wiggle Well”, whose key feature is Ge concentration oscillations inside well. Experimentally, show placing...
A primary obstacle in scaling up quantum computing platforms based on semiconductor dots (QDs) is the full automation of initialization and control. Using ideas from machine learning (ML), pattern recognition, optimization, authors implement an autotuning protocol that needs no human intervention to navigate between QD states real time. convolutional neural network identifies $i\phantom{\rule{0}{0ex}}n$ $s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ measurements;...
The energies of valley-orbit states in silicon quantum dots are determined by an as yet poorly understood interplay between interface roughness, orbital confinement, and electron interactions. Here, we report measurements one- two-electron state the dot potential is modified changing gate voltages, calculate these same using full configuration interaction calculations. results enable understanding physical contributions a new probe well interface.
Multi-electron semiconductor quantum dots have found wide application in qubits, where they enable readout and enhance polarizability. However, coherent control such has typically been restricted to only the lowest two levels, strongly interacting regime not realized. Here we report of eight different resonances a silicon-based dot. We use qubit perform spectroscopy, revealing dense set energy levels with characteristic spacing far smaller than single-particle energy. By comparing full...
Silicon-germanium heterostructures have successfully hosted quantum dot qubits, but the intrinsic near-degeneracy of two lowest valley states poses an obstacle to high fidelity computing. We present a modification Si/SiGe heterostructure by inclusion spike in germanium concentration within well order increase splitting. The is grown chemical vapor deposition and magnetospectroscopy performed on gate-defined dots measure excited state spectrum. demonstrate large widely tunable splitting as...
The promise of quantum computation is contingent upon physical qubits with both low gate error rate and broad scalability. Silicon-based spins are a leading qubit platform, but demonstrations to date have not utilized fabrication processes capable extending arrays in two dimensions while maintaining complete control individual spins. Here, we implement an interconnect process, common semiconductor manufacturing, multiple back-end-of-line layers show extendable two-dimensional array fully...
We present an improved fabrication process for overlapping aluminum gate quantum dot devices on Si/SiGe heterostructures that incorporates low-temperature inter-gate oxidation, thermal annealing of oxide, on-chip electrostatic discharge (ESD) protection and optimized interconnect budget considerations. This reduces gate-to-gate leakage, damage from ESD, dewetting formation undesired alloys in device interconnects. Additionally, cross-sectional scanning transmission electron microscopy (STEM)...
Understanding the interactions that couple gate-defined quantum-dot qubits is an important step to using such devices in quantum computing. For double-quantum-dot with effective charge dipole moment, a capacitive dipole-dipole interaction can yield coherent coupling between neighboring qubits. Here researchers reveal tunability of this capacitive-coupling energy applied gate voltages quadruple-quantum-dot array, tuning from 15 32 GHz. Modeling system as network nodes joined by capacitors,...
Abstract Fast operations, an easily tunable Hamiltonian, and a straightforward two-qubit interaction make charge qubits useful tool for benchmarking device performance exploring dynamics. Here, we tune linear chain of four Si/SiGe quantum dots to host two double dot qubits. Using the capacitance between mediate strong interaction, simultaneously drive coherent transitions generate correlations We then sequentially pulse one qubit conditionally on state other. find that conditional π...
In the physical sciences, there is an increased need for robust feature representations of image data: acquisition, in generalized sense two-dimensional data, now widespread across a large number fields, including quantum information science, which we consider here. While traditional features are widely utilized such cases, their use rapidly being supplanted by Neural Network-based techniques that often sacrifice explainability exchange high accuracy. To ameliorate this trade-off, propose...
We develop an engineered microwave environment for coupling high Q superconducting resonators to quantum dots using a multilayer fabrication stack dot control wiring. Analytical and numerical models are presented, which show that resonator quality factors can be attained by either minimizing the parasitic capacitance leads or creating low effective environmental impedance at cavity frequency. implement later approach fabricating characteristic (Zg≈10 Ω) microstrips on-chip bias wiring of...
Latching techniques are widely used to enhance readout of qubits. These methods require precise tuning multiple tunnel rates, which can be challenging achieve under realistic experimental conditions, such as when a qubit is coupled single reservoir. Here, we present method for single-shot measurement quantum dot with reservoir using latched-readout scheme. Our approach involves pulsing barrier gate dynamically control qubit-to-reservoir that readily applicable the latched various spin-based...
Abstract The rapid development of quantum dot (QD) devices for computing has necessitated more efficient and automated methods device characterization tuning. Many the measurements acquired during tuning process come in form images that need to be properly analyzed guide subsequent steps. By design, features present such capture certain behaviors or states measured QD devices. When considered carefully, can aid control calibration An important example are so-called triangle plots , which...
A primary method of reading out a quantum dot hybrid qubit involves projection the logical basis onto distinct charge states that are readily detected by an integrated sensing dot. However, in simplest configuration, excited state decays rapidly, making single-shot readout challenging. Here, we demonstrate procedure where is latched to metastable configuration whose lifetime tunnel-rate limited, persisting here as long 2.5 ms. Additionally, show working (4,1)–(3,2) enables window larger and...
Aspects of modern information systems challenging computational and statistical analysis are dynamic complexity, high dimensionality inherent stochasticity. We outline the use geometric methods to provide neighbourhoods for data visualization monitoring algorithms, dynamics stochastic behaviour trajectories. Geometrization models real phenomena give valuable insights through features that invariant under choice coordinate representation. Here we look at aspects relating study problems,...
Fast operations, an easily tunable Hamiltonian, and a straightforward two-qubit interaction make charge qubits useful tool for benchmarking device performance exploring dynamics. Here, we tune linear chain of four Si/SiGe quantum dots to host two double dot qubits. Using the capacitance between mediate strong interaction, simultaneously drive coherent transitions generate correlations We then sequentially pulse one qubit conditionally on state other. find that conditional $\pi$-rotation can...