A5101798246- Quantum and electron transport phenomena
- Quantum Information and Cryptography
- Physics of Superconductivity and Magnetism
- Quantum Computing Algorithms and Architecture
- Block Copolymer Self-Assembly
- Magnetism in coordination complexes
- Lanthanide and Transition Metal Complexes
- Magnetic properties of thin films
- Electron Spin Resonance Studies
- Mechanical and Optical Resonators
- Quantum optics and atomic interactions
- Anodic Oxide Films and Nanostructures
- Quantum-Dot Cellular Automata
- Particle physics theoretical and experimental studies
- Advanced NMR Techniques and Applications
- Photonic and Optical Devices
- Surface and Thin Film Phenomena
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Parallel Computing and Optimization Techniques
- Advanced Thermodynamics and Statistical Mechanics
- Gyrotron and Vacuum Electronics Research
- Nanomaterials for catalytic reactions
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
Fermi National Accelerator Laboratory
2022-2024
University of Colorado Boulder
2018-2023
National Institute of Standards and Technology
2017-2021
Lawrence Livermore National Laboratory
2020
United States Naval Research Laboratory
2020
Harvard University Press
2018
University of Waterloo
2012-2016
Scientific and Technological Research Council of Turkey
2015
Dartmouth College
2010
Amherst College
2004-2008
Ordered nanoporous films have been generated via selective degradation of self-assembled block copolymer polystyrene (PS) and poly(methylmethacrylate) (PMMA), which contain oriented cylindrical microdomains. Deep UV irradiation degrades the PMMA, can be rinsed away, leaving an ordered array circular holes in a film cross-linked PS (see Figure).
A novel approach to highly ordered and modular nanoelectrode arrays (NEAs) has been developed using block copolymer self-assembly. Variable scan rate cyclic voltammetry studies were performed characterize the NEA. At low rates, NEA behaves similar a macroelectrode, while at high rates nanoelectrodes act independently. This is an important feature for real-time in vivo sensing other electroanalytical applications.
Transmon qubits are ubiquitous in the pursuit of quantum computing using superconducting circuits. However, they have some drawbacks that still need to be addressed. Most importantly, scalability transmons is limited by large device footprint needed reduce participation lossy capacitive parts circuit. In this work, we investigate and evaluate losses an alternative geometry, namely, merged-element transmon (mergemon). To end, replace external shunt capacitor a traditional with intrinsic...
Improving the qubit's lifetime (T1) is crucial for fault-tolerant quantum computing. Recent advancements have shown that replacing niobium (Nb) with tantalum (Ta) as base metal significantly increases T1, likely due to a less lossy native surface oxide. However, understanding formation mechanism and nature of both oxides still limited. Using aberration-corrected transmission electron microscopy energy loss spectroscopy, we found Ta oxide has fewer suboxides than Nb We observed an abrupt...
Quantum networks will enable extraordinary capabilities for communicating and processing quantum information. These require a reliable means of storage, retrieval, manipulation states at the network nodes. A node receives one or more coherent inputs sends conditional output to next cascaded in through channel. Here, we demonstrate this basic functionality by using interference mechanism electromagnetically induced transparency transmon qubit coupled superconducting resonator. First, apply...
We report experiments on superconducting flux qubits in a circuit quantum electrodynamics (cQED) setup. Two qubits, independently biased and controlled, are coupled to coplanar waveguide resonator. Dispersive qubit state readout reaches maximum contrast of $72\,\%$. find intrinsic energy relaxation times at the symmetry point $7\,\mu\text{s}$ $20\,\mu\text{s}$ levels noise $2.6\,\mu \Phi_0/\sqrt{\text{Hz}}$ $2.7\,\mu 1 Hz for two qubits. discuss origin decoherence measured devices. These...
Fabrication of sub-micron Josephson junctions is demonstrated using standard processing techniques for high-coherence, superconducting qubits. These are made in two separate lithography steps with normal-angle evaporation. Most significantly, this work demonstrates that it possible to achieve high coherence formed on aluminum surfaces cleaned situ Ar milling before the junction oxidation. This method eliminates angle-dependent shadow masks typically used small junctions. Therefore, conducive...
Conventional lithographic exposure is used to selectively degrade regions of a self-assembled diblock copolymer film obtain honeycomblike nanoporous array template with arbitrary lateral design. Combined other process steps, this enables the fabrication arrays nanostructures interfaced electrical probes for device applications. To demonstrate, unique magnetotransport fabricated, consisting an electrodeposited Co nanowires standing atop thin gold patterned into four-probe resistor...
We describe a kinetic inductance traveling-wave (KIT) amplifier suitable for superconducting quantum information measurements and characterize its wideband scattering noise properties. use mechanical microwave switches to calibrate the four parameters up device input output connectors at dilution refrigerator base temperature tunable load noise. Finally, we demonstrate high fidelity simultaneous dispersive readout of two transmon qubits. The KIT provides low-noise amplification both tones...
The speed of elementary quantum gates, particularly two-qubit ultimately sets the limit on at which circuits can operate. In this work, we experimentally demonstrate commonly used gates nearly fastest possible allowed by physical interaction strength between two superconducting transmon qubits. We achieve implementing experimental designed using a machine-learning-inspired optimal control method. Importantly, our method only requires single-qubit drive to be moderately larger than an...
The investigation of two-level-state (TLS) loss in dielectric materials and interfaces remains at the forefront research superconducting quantum circuits. We demonstrate a method TLS extraction thin film by using lumped element resonator fabricated from superconductor-dielectric-superconductor trilayer. extract formulating circuit model for with then fitting to this measurements set three designs: coplanar waveguide resonator, an interdigitated capacitor, parallel plate capacitor that...
We present experiments on the dynamics of a two-state parametric fluctuator in superconducting flux qubit. In spectroscopic measurements, manifests itself as doublet line. When qubit is excited resonance with one two lines, correlation readout results exhibits an exponential time decay which provides measure transition rate. The rate increases temperature interval 40 to 158 mK. Based magnitude and line splitting we conclude that fluctuation induced by quasiparticle tunneling. These...
We use millimeter wave radiation to manipulate the populations of energy levels a single crystal molecular magnet Fe8. When continuous is in resonance with transitions from ground state first excited state, equilibrium magnetization exhibits dip. The position this dip varies linearly frequency. Our results provide lower bound 0.17 ns for transverse relaxation time and suggest possibility that single-molecule magnets might be utilized quantum computation.
Epitaxially grown superconductor/dielectric/superconductor trilayers have the potential to form high-performance superconducting quantum devices and may even allow scalable computing with low-surface-area qubits such as merged-element transmon. In this work, we measure power-independent loss two-level-state (TLS) of epitaxial, wafer-bonded, substrate-removed Al/GaAs/Al by measuring lumped element microwave resonators at millikelvin temperatures down single-photon powers. The device is...
We measure magnetization changes in a single crystal of the single-molecule magnet Fe8 when exposed to intense, short (⩽20 μs) pulses microwave radiation resonant with m = 10 9 transition. find that induces phonon bottleneck system time scale ∼5 μs. The bottleneck, turn, drives spin dynamics, allowing observation thermally assisted tunneling between states at 100 ns scale. Detailed numerical simulations quantitatively reproduce data and yield spin-phonon relaxation T1∼40 ns.
It has been known since the early days of quantum mechanics that hyperbolic secant pulses possess unique property they can perform cyclic evolution on two-level systems independently pulse detuning. More recently, it was realized induce detuning- controlled phases without changing state populations. Here, we experimentally demonstrate properties superconducting transmon qubits and contrast them with more commonly used Gaussian square waves. We further show these be exploited to implement...
Various start-up developers and academic researchers have investigated the usage of blockchain as a data storage medium due to advantages offered by its tamper-proof decentralized nature. However, there not been many attempts provide standard platform for virtually storing states unique tangible entities their subsequent modifications. In this paper, we propose NFTracer, non-fungible token tracking proof-of-concept based on Hyperledger Composer Fabric Blockchain. To achieve capabilities our...
We used a Josephson junction as radiation detector to look for evidence of the emission electromagnetic during magnetization avalanches in crystal assembly Mn_12-Acetate. The exhibits at several magnetic fields temperature range from 1.8 2.6 K with durations order 1 ms. Although recent study shows bursts these [J. Tejada, et al., Appl. Phys. Lett. {\bf 84}, 2373 (2004)], we were unable detect any significant well-defined frequencies. A control experiment external pulses allows us determine...
Resonant microwave radiation applied to a single crystal of the molecular magnet Fe8 induces dramatic changes in sample's magnetization. Transitions between excited states are found even though at nominal system temperature these levels have negligible population. We find evidence that sample heats significantly when resonance condition is met. In addition, heating observed after short pulse intense has been turned off, indicating spin out equilibrium with lattice.
High-fidelity single- and two-qubit gates are essential building blocks for a fault-tolerant quantum computer. While there has been much progress in suppressing single-qubit gate errors superconducting qubit systems, still suffer from error rates that orders of magnitude higher. One limiting factor is the residual ZZ-interaction, which originates coupling between computational states higher-energy states. this interaction usually viewed as nuisance, here we experimentally demonstrate it can...
Microwave radiation applied to single-molecule magnets can induce large magnetization changes when the is resonant with transitions between spin levels. These are interpreted as due heating of sample by microwaves. Pulsed-radiation studies show that continues decrease after has been turned off a rate consistent spin's characteristic relaxation rate. The measured increases pulse duration and microwave power, indicating greater absorbed energy results in higher temperature. We also performed...