202 research outputs found
Implementing and characterizing precise multi-qubit measurements
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 non-destructive measurements of specific correlations within that
system. We realize such measurements by employing a protocol adapted from [S.
Nigg and S. M. 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 (cQED) 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 back-action 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
non-demolition. We further show that both results are improved significantly by
an additional error-heralding measurement. The analyses presented here form a
useful basis for the future characterization and validation of quantum
measurements, anticipating the demands of emerging quantum technologies.Comment: 10 pages, 5 figures, plus supplemen
Sex Differences in Neurological Emergencies Presenting to Multiple Urban Level 1 Trauma Centers
Previous studies have suggested that there are sex differences in the treatment and outcome of neurological emergencies; however, research identifying the role these sex differences play in the management of neurological emergencies is lacking. More knowledge of the way sex factors into the pathophysiology of neurological emergencies will be helpful in improving outcomes for these patients. The aim of this cross-sectional study was to assess the prevalence and management of neurological emergencies while evaluating sex differences in the diagnosis and treatment of these emergencies. We analyzed a cohort of 530 adult patients from four level 1 trauma centers over a period of 4 weeks who had a chief complaint of a neurological emergency, including seizures, cerebrovascular events, headache disorders, traumatic brain injuries, and central nervous system infections. Among patients with neurological emergencies, a significantly lower proportion of female patients underwent neurosurgery and were admitted to the intensive care unit compared to male patients, but there were no significant differences between sexes in the time of symptom onset, type of hospital transportation, amount of neuroimaging performed, admission rates, hospital length of stay, and disposition from the emergency department. Although female patients were more likely to have a chief complaint of headache compared to traumatic injuries in male patients, this was not statistically significant. A significantly higher proportion of female patients had health insurance coverage than male patients
Addressing food and nutrition insecurity in the Caribbean through domestic smallholder farming system innovation
Structural conditions underlying the development of CARICOM’s two-tiered agricultural innovation system depict diverse drivers of change over time, versus institutional inertia of export-oriented formal institutions and the neglect of informal domestic markets. Key principles of taking an agroecological approach would include: supporting diversity and redundancy, building connectivity, managing slow variables and feedbacks, improving understanding of socioecological systems as complex adaptive systems, and encouraging polycentric governance systems. In this paper, we review the conditions that have been undermining sustainable food and nutrition security in the Caribbean, focusing on issues of history, economy, and innovation
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