Novel III-Nitride growth by ultraviolet radiation assisted metal organic molecular beam epitaxy

While modern epitaxial methods enable precise, monolayer (ML) control of the thin film deposition process, the complexity of certain device structures is ultimately limited by the capability and cost of the fabrication process. The objective of this work is to develop a pathway toward three-dimensional epitaxy (3DE) - the ability to intentionally and dynamically pattern regions of a film during the deposition process - in order to enable novel device concepts unbound by the traditional device fabrication paradigm. This work pioneers UV-assisted metal organic molecular beam epitaxy (MOMBE) as a particularly selective epitaxy technique to create a pathway toward 3DE of a crucial and topical material system - the III-Nitrides. A novel UV-assisted MOMBE system is developed enabling intense UV irradiation of films during growth. High quality, heavily (unintentionally) carbon-doped GaN is successfully grown by NH₃-based MOMBE and for the first time InGaN, AlGaN, and magnesium-doped GaN are demonstrated by NH₃-based MOMBE. Intense UV irradiation of films during NH₃-based MOMBE significantly enhances photo-desorption of species during the growth process, subsequently affecting the resultant InGaN alloy composition, carbon dopant concentration, or magnesium dopant concentration. A digital micromirror device is introduced to pattern incident UV radiation during InGaN growth, demonstrating that the effects of photoexcitation during MOMBE which have been proposed, discovered, and identified by this thesis indeed can be leveraged to deposit an InGaN film that is compositionally patterned within the growth plane. The results demonstrate that the new approach presented herein is possible for the 3DE of III-Nitrides if additional challenges in practical implementation can be overcome.Ph.D.Committee Chair: Doolittle, W. Alan; Committee Member: Carter, W. Brent; Committee Member: Ferguson, Ian T.; Committee Member: Frazier, A. Bruno; Committee Member: Rincon-Mora, Gabriel A

Characterizing non-Markovian Off-Resonant Errors in Quantum Gates

As quantum gates improve, it becomes increasingly difficult to characterize the remaining errors. Here we describe a class of coherent non-Markovian errors -- excitations due to an off-resonant drive -- that occur naturally in quantum devices that use time-dependent fields to generate gate operations. We show how these errors are mischaracterized using standard Quantum Computer Verification and Validation (QCVV) techniques that rely on Markovianity and are therefore often overlooked or assumed to be incoherent. We first demonstrate off-resonant errors within a simple toy model of Z-gates created by the AC Stark effect, then show how off-resonant errors manifest in all gates driven on a fixed-frequency transmon architecture, a prominent example being incidental cross-resonance interaction driven during single-qubit gates. Furthermore, the same methodology can access the errors caused by two-level systems (TLS), showing evidence of coherent, off-resonant interactions with subsystems that are not intentional qubits. While we explore these results and their impact on gate error for fixed-frequency devices, we note that off-resonant excitations potentially limit any architectures that use frequency selectivity.Comment: fixed typos, updated references, and improved explanation

Eating disorder risk, exercise dependence, and body weight dissatisfaction among female nutrition and exercise science university majors

Background and Aims: Past research has examined eating disorder risk among college students majoring in Nutrition and has suggested an increased risk, while other studies contradict these results. Exercise Science majors, however, have yet to be fully examined regarding their risk for eating disorders and exercise dependence. Based on pressures to fit the image associated with careers related to these two disciplines, research is warranted to examine the potential risk for both eating disorder and exercise dependence. The purpose of this study is to compare eating disorder risk, exercise dependence, and body weight dissatisfaction (BWD) between Nutrition and Exercise Science majors, compared to students outside of these career pathways. Methods: Participants (n = 89) were divided into three groups based on major; Nutrition majors (NUTR; n = 31), Exercise Science majors (EXSC; n = 30), and other majors (CON; n = 28). Participants were given the EAT-26 questionnaire and the Exercise Dependence Scale. BWD was calculated as the discrepancy between actual BMI and ideal BMI. Results: The majority of participants expressed a desire to weigh less (83%) and EXSC had significantly (p = .03) greater BWD than NUTR. However, there were no significant differences in eating disorder risk or exercise dependence among majors. Discussion and Conclusions: This study suggested there was no significant difference in eating disorder risk or exercise dependence between the three groups (NUTR, EXSC, and CON)

Native two-qubit gates in fixed-coupling, fixed-frequency transmons beyond cross-resonance interaction

Fixed-frequency superconducting qubits demonstrate remarkable success as platforms for stable and scalable quantum computing. Cross-resonance gates have been the workhorse of fixed-coupling, fixed-frequency superconducting processors, leveraging the entanglement generated by driving one qubit resonantly with a neighbor's frequency to achieve high-fidelity, universal CNOTs. Here, we use on-resonant and off-resonant microwave drives to go beyond cross-resonance, realizing natively interesting two-qubit gates that are not equivalent to CNOTs. In particular, we implement and benchmark native ISWAP, SWAP, $\sqrt{\text{ISWAP}}$, and BSWAP gates. Furthermore, we apply these techniques for an efficient construction of the B-gate: a perfect entangler from which any two-qubit gate can be reached in only two applications. We show these native two-qubit gates are better than their counterparts compiled from cross-resonance gates. We elucidate the resonance conditions required to drive each two-qubit gate and provide a novel frame tracking technique to implement them in Qiskit.Comment: 11 pages, comments welcom

Comparison of Glucose Monitoring Methods during Steady-State Exercise in Women

Data from Continuous Glucose Monitoring (CGM) systems may help improve overall daily glycemia; however, the accuracy of CGM during exercise remains questionable. The objective of this single group experimental study was to compare CGM-estimated values to venous plasma glucose (VPG) and capillary plasma glucose (CPG) during steady-state exercise. Twelve recreationally active females without diabetes (aged 21.8 ± 2.4 years), from Central Washington University completed the study. CGM is used by individuals with diabetes, however the purpose of this study was to first validate the use of this device during exercise for anyone. Data were collected between November 2009 and April 2010. Participants performed two identical 45-min steady-state cycling trials (~60% Pmax) on non-consecutive days. Glucose concentrations (CGM-estimated, VPG, and CPG values) were measured every 5 min. Two carbohydrate gel supplements along with 360 mL of water were consumed 15 min into exercise. A product-moment correlation was used to assess the relationship and a Bland-Altman analysis determined error between the three glucose measurement methods. It was found that the CGM system overestimated mean VPG (mean absolute difference 17.4 mg/dL (0.97 mmol/L)) and mean CPG (mean absolute difference 15.5 mg/dL (0.86 mmol/L)). Bland-Altman analysis displayed wide limits of agreement (95% confidence interval) of 44.3 mg/dL (2.46 mmol/L) (VPG compared with CGM) and 41.2 mg/dL (2.29 mmol/L) (CPG compared with CGM). Results from the current study support that data from CGM did not meet accuracy standards from the 15197 International Organization for Standardization (ISO)

Benchmarking Quantum Processor Performance at Scale

As quantum processors grow, new performance benchmarks are required to capture the full quality of the devices at scale. While quantum volume is an excellent benchmark, it focuses on the highest quality subset of the device and so is unable to indicate the average performance over a large number of connected qubits. Furthermore, it is a discrete pass/fail and so is not reflective of continuous improvements in hardware nor does it provide quantitative direction to large-scale algorithms. For example, there may be value in error mitigated Hamiltonian simulation at scale with devices unable to pass strict quantum volume tests. Here we discuss a scalable benchmark which measures the fidelity of a connecting set of two-qubit gates over $N$ qubits by measuring gate errors using simultaneous direct randomized benchmarking in disjoint layers. Our layer fidelity can be easily related to algorithmic run time, via $\gamma$ defined in Ref.\cite{berg2022probabilistic} that can be used to estimate the number of circuits required for error mitigation. The protocol is efficient and obtains all the pair rates in the layered structure. Compared to regular (isolated) RB this approach is sensitive to crosstalk. As an example we measure a $N=80~(100)$ qubit layer fidelity on a 127 qubit fixed-coupling "Eagle" processor (ibm\_sherbrooke) of 0.26(0.19) and on the 133 qubit tunable-coupling "Heron" processor (ibm\_montecarlo) of 0.61(0.26). This can easily be expressed as a layer size independent quantity, error per layered gate (EPLG), which is here $1.7\times10^{-2}(1.7\times10^{-2})$ for ibm\_sherbrooke and $6.2\times10^{-3}(1.2\times10^{-2})$ for ibm\_montecarlo.Comment: 15 pages, 8 figures (including appendices

Aerodynamic Tests of the Space Launch System for Database Development

The Aerosciences Branch (EV33) at the George C. Marshall Space Flight Center (MSFC) has been responsible for a series of wind tunnel tests on the National Aeronautics and Space Administration's (NASA) Space Launch System (SLS) vehicles. The primary purpose of these tests was to obtain aerodynamic data during the ascent phase and establish databases that can be used by the Guidance, Navigation, and Mission Analysis Branch (EV42) for trajectory simulations. The paper describes the test particulars regarding models and measurements and the facilities used, as well as database preparations