Superconducting circuits have attracted growing interest in recent years as a promising candidate for fault-tolerant quantum information processing. Extensive efforts have always been taken to completely shield these circuits from external magnetic fields to protect the integrity of the superconductivity. Here we show vortices can improve the performance of superconducting qubits by reducing the lifetimes of detrimental single-electron-like excitations known as quasiparticles. Using a contactless injection technique with unprecedented dynamic range, we quantitatively distinguish between recombination and trapping mechanisms in controlling the dynamics of residual quasiparticle, and show quantized changes in quasiparticle trapping rate because of individual vortices. These results highlight the prominent role of quasiparticle trapping in future development of superconducting qubits, and provide a powerful characterization tool along the way.

There are two general requirements to harness the computational power of quantum mechanics: the ability to manipulate the evolution of an isolated system and the ability to faithfully extract information from it. Quantum error correction and simulation often make a more exacting demand: the ability to perform nondestructive measurements of specific correlations within that system. We realize such measurements by employing a protocol adapted from Nigg and Girvin [Phys. Rev. Lett. 110, 243604 (2013)], enabling real-time selection of arbitrary register-wide Pauli operators. Our implementation consists of a simple circuit quantum electrodynamics module of four highly coherent 3D transmon qubits, collectively coupled to a high-Q superconducting microwave cavity. As a demonstration, we enact all seven nontrivial subset-parity measurements on our three-qubit register. For each, we fully characterize the realized measurement by analyzing the detector (observable operators) via quantum detector tomography and by analyzing the quantum backaction via conditioned process tomography. No single quantity completely encapsulates the performance of a measurement, and standard figures of merit have not yet emerged. Accordingly, we consider several new fidelity measures for both the detector and the complete measurement process. We measure all of these quantities and report high fidelities, indicating that we are measuring the desired quantities precisely and that the measurements are highly nondemolition. We further show that both results are improved significantly by an additional error-heralding measurement. The analyses we present here form a useful basis for the future characterization and validation of quantum measurements, anticipating the demands of emerging quantum technologies.

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Study Design. A cross-sectional study was performed using the National Institutes of Health All of Us survey database. Objective. The aim of this study was to assess socioeconomic and racial disparities in the perception of personal health, health literacy, and healthcare access among spine oncology patients. Summary of Background Data. Racial, ethnic, and socioeconomic disparities in health literacy and perception of health status have been described for many disease processes. However, few studies have assessed the prevalence of these disparities among spine oncology patients. Methods. Adult spine oncology patients, identified using ICD-9/10-CM codes, were categorized by race/ethnicity: White/Caucasian (WC), Black/African-American (BAA), and Non-White Hispanic (NWH). Demographics and socioeconomic status were assessed. Questionnaire responses regarding baseline health status, perception of health status, health literacy, and barriers to healthcare were compared. Results. Of the 1,175 patients identified, 207 (17.6%) were BAA, 267 (22.7%) were NWH, and 701 (59.7%) were WC. Socioeconomic status varied among cohorts, with WC patients reporting higher levels of education (P<0.001), annual income greater than $50K (P<0.001), and home ownership (P<0.001). BAA and NWH patients reported greater rates of 7-day “Severe fatigue” (P<0.001) and “10/10 pain” (P<0.001) and lower rates of “Completely” able to perform everyday activities (P<0.001). WC patients had a higher response rate for “Excellent/Very Good” regarding their own general health (P<0.001) and quality (P<0.001). The WC cohort had a significantly higher proportion of patients responding “Never” when assessing difficulty understanding (P<0.001) and needing assistance with health materials (P<0.001). BAA and NWH were significantly less likely to report feeling “Extremely” confident with medical forms (P<0.001). BAA and NWH had significantly higher response rates to feeling “Somewhat Worried” about healthcare costs (P<0.001) and with delaying medical care given “Can’t Afford Co-pay” (P<0.001). Conclusion. We identified disparities in perception of health status, literacy, and access among spine oncology patients. Level of Evidence. 4

We have used a kinematic technique to distinguish top quark pair production from background in pp¯ collisions at √s=1.8 TeV, applied to 67 pb−1 of data. We define a sample of W+≥3 jet events in which the jets are produced at large angles relative to the incident beams. In this sample, we find an excess of events with large jet transverse energies relative to expectations from background. The excess is consistent with top quark production; a large fraction of events in this kinematic region contains b jets. We interpret these results as evidence that most of the selected events are from tt¯ decay

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