A5052735257- Quantum and electron transport phenomena
- Quantum Computing Algorithms and Architecture
- Advancements in Semiconductor Devices and Circuit Design
- Quantum Information and Cryptography
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- International Law and Human Rights
- Quantum-Dot Cellular Automata
- International Maritime Law Issues
- Advanced Electron Microscopy Techniques and Applications
- Global Peace and Security Dynamics
- International Law and Aviation
- Quantum Mechanics and Applications
- Silicon and Solar Cell Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Law, logistics, and international trade
- Topological Materials and Phenomena
- International Arbitration and Investment Law
- Maritime Security and History
- Magnetic properties of thin films
- Silicon Nanostructures and Photoluminescence
- Photonic and Optical Devices
- Electron and X-Ray Spectroscopy Techniques
- Physics of Superconductivity and Magnetism
- Surface and Thin Film Phenomena
IonQ (United States)
2023-2024
Microsoft (United States)
2014-2023
Division of Undergraduate Education
2023
Diabetes Canada
2023
Nova Scotia Department of Energy
2023
Sandia National Laboratories
2014-2021
Microsoft Research (United Kingdom)
2021
Sandia National Laboratories California
2014-2020
The University of Sydney
2020
Quantum (Australia)
2020
Quantum information processors promise fast algorithms for problems inaccessible to classical computers. But since qubits are noisy and error-prone, they will depend on fault-tolerant quantum error correction (FTQEC) compute reliably. can protect against general noise if -- only the in each physical qubit operation is smaller than a certain threshold. The threshold errors quantified by their diamond norm. Until now, have been assessed primarily randomized benchmarking, which reports...
We propose a quantum dot qubit architecture that has an attractive combination of speed and fabrication simplicity. It consists double with one electron in two electrons the other. The itself is set states total spin numbers ${S}^{2}=3/4$ ($S=1/2$) ${S}_{z}=\ensuremath{-}1/2$, different being singlet triplet doubly occupied dot. Gate operations can be implemented electrically highly tunable, enabling fast implementation one- two-qubit gates simpler geometry fewer than other proposed...
Topological phases of matter can enable highly stable qubits with small footprints, fast gate times, and digital control. These hardware-protected must be fabricated a material combination in which topological phase reliably induced. The challenge: disorder destroy the obscure its detection. This paper reports on devices low enough to pass gap protocol, thereby demonstrating gapped superconductivity paving way for new qubit.
The qubit is the fundamental building block of a quantum computer. We fabricate in silicon double-quantum dot with an integrated micromagnet which basis states are singlet state and spin-zero triplet two electrons. Because micromagnet, magnetic field difference ΔB between sides double large enough to enable achievement coherent rotation qubit's Bloch vector around different axes sphere. By measuring decay oscillations, inhomogeneous spin coherence time T2* determined. at many values exchange...
We show that the quantum dynamics of interacting and noninteracting particles are fundamentally different in context solving a particular computational problem. Specifically, we consider graph isomorphism problem, which one wishes to determine whether two graphs isomorphic (related each other by relabeling vertices), focus on class with particularly high symmetry called strongly regular (SRGs). study Green's functions characterize dynamical evolution single-particle two-particle walks pairs...
Fast quantum oscillations of a charge qubit in double dot fabricated Si/SiGe heterostructure are demonstrated and characterized experimentally. The measured inhomogeneous dephasing time ${T}_{2}^{*}$ ranges from 127 ps to 2.1 ns; it depends substantially on how the energy difference two states varies with external voltages, consistent decoherence process that is dominated by detuning noise (charge changes asymmetry qubit's double-well potential). In regime shortest ${T}_{2}^{*}$, applying...
The silicon metal-oxide-semiconductor (MOS) material system is technologically important for the implementation of electron spin-based quantum information technologies. Researchers predict need an integrated platform in order to implement useful computation, and decades advancements microelectronics fabrication lends itself this challenge. However, fundamental concerns have been raised about MOS interface (e.g. trap noise, variations g-factor practical multi-QDs). Furthermore, two-axis...
Quantum computers are rapidly becoming more capable, with dramatic increases in both qubit count \cite{kim2023evidence} and quality \cite{moses2023race}. Among different hardware approaches, trapped-ion quantum processors a leading technology for computing, established high-fidelity operations architectures promising scaling. Here, we demonstrate thoroughly benchmark the IonQ Forte system: configured as single-chain 30-qubit computer all-to-all operations. We assess performance of our...
We use NMR quantum simulators to study antiferromagnetic Ising spin chains undergoing phase transitions. Taking advantage of the sensitivity systems near criticality, we detect critical points transitions using a direct measurement Loschmidt echo. test our for even and odd numbers spins, compare experimental results theoretical predictions.
A quantum-dot hybrid qubit formed from three electrons in a double quantum dot has the potential for great speed, due to presence of level crossings where becomes chargelike. Here, we show how exploit implement fast pulsed gating. We develop one- and two-qubit dc gates that are simpler than previously proposed ac gates. obtain closed-form solutions control sequences (subnanosecond) can achieve high fidelities.
We introduce and demonstrate experimentally: (1) a framework called "gate set tomography" (GST) for self-consistently characterizing an entire of quantum logic gates on black-box device; (2) explicit closed-form protocol linear-inversion gate tomography (LGST), whose reliability is independent pathologies such as local maxima the likelihood; (3) simple objectively scoring accuracy tomographic estimate without reference to target gates, based how well it predicts testing experiments. use...
State of the art qubit systems are reaching gate fidelities required for scalable quantum computation architectures. Further improvements in fidelity gates demands characterization and benchmarking protocols that efficient, reliable extremely accurate. Ideally, a protocol should also provide information on how to rectify residual errors. Gate set tomography (GST) is one such designed give detailed as-built qubits. We implemented GST high-fidelity electron-spin confined by single 31P atom...
Many vexing, complicated, and important problems of international law relate in some way to reservations multilateral treaties. No doubt, the right states make treaties is functioning an legal system, a major component which As Edwin Hoyt pointed out two decades ago, unanimity rule has given much more flexible standard permits under many circumstances. Thus, position adopted here that questions should be asked about when how are used what their aggregate impact been. This approach contrasts...
Individual donors in silicon chips are used as quantum bits with extremely low error rates. However, physical realizations have been limited to one donor because their atomic size causes fabrication challenges. Quantum dot qubits, contrast, highly adjustable using electrical gate voltages. This adjustability could be leveraged deterministically couple dots arrays of qubits. In this work, we demonstrate the coherent interaction a 31P electron metal-oxide-semiconductor dot. We form logical...
Last year, Salfi et al. made the first direct measurements of a donor wave function and found extremely good theoretical agreement with atomistic tight-binding theory results [Salfi al., Nat. Mater. 13, 605 (2014)]. Here, we show that multivalley effective mass theory, applied properly, does achieve close hence gives reliable predictions. To demonstrate this, variationally solve coupled six-valley Shindo-Nara equations, including silicon's full Bloch functions. Surprisingly, find functions...
Quantum dots in silicon are promising candidates for implementation of solid-state quantum information processing. It is important to understand the effects multiple conduction band valleys on properties these devices. Here we introduce a novel, systematic effective mass theory valley-orbit coupling disordered systems. This reveals hybridization that detrimental storing valley degree freedom, including non-vanishing dipole matrix elements between states and altered intervalley tunneling.
Selective area growth is a promising technique to realize semiconductor–superconductor hybrid nanowire networks, potentially hosting topologically protected Majorana-based qubits. In some cases, however, such as the molecular beam epitaxy of InSb on InP or GaAs substrates, nucleation and selective conditions do not necessarily overlap. To overcome this challenge, we propose metal-sown (MS SAG) technique, which allows decoupling deposition by temporarily isolating these stages. It consists...
We measure the excited-state spectrum of a Si/SiGe quantum dot as function in-plane magnetic field and identify spin lowest three eigenstates in an effective two-electron regime. extract singlet-triplet splitting, essential parameter for qubits, from data. find it to be tunable by lateral displacement dot, which is realized changing two gate voltages on opposite sides device. present calculations showing data are consistent with first excited state valley-orbit state.
We study the dephasing of two-electron states in a single quantum dot both GaAs and Si. investigate induced by electron-phonon coupling charge noise analytically for pure orbital excitations Si, as well valley In GaAs, polar optical phonons give rise to most important contribution, leading typical rate ~5.9 GHz. For intervalley lead ~140 kHz ~1.1 MHz excitations. harmonic, disorder-free dots, is highly suppressed excitations, since neither has an appreciable dipole moment couple electric...