1,979 research outputs found
Imaging Photon Lattice States by Scanning Defect Microscopy
Microwave photons inside lattices of coupled resonators and superconducting
qubits can exhibit surprising matter-like behavior. Realizing such open-system
quantum simulators presents an experimental challenge and requires new tools
and measurement techniques. Here, we introduce Scanning Defect Microscopy as
one such tool and illustrate its use in mapping the normal-mode structure of
microwave photons inside a 49-site Kagome lattice of coplanar waveguide
resonators. Scanning is accomplished by moving a probe equipped with a sapphire
tip across the lattice. This locally perturbs resonator frequencies and induces
shifts of the lattice resonance frequencies which we determine by measuring the
transmission spectrum. From the magnitude of mode shifts we can reconstruct
photon field amplitudes at each lattice site and thus create spatial images of
the photon-lattice normal modes
Preliminary results of flight tests of vortex attenuating splines
Flight tests have been conducted to evaluate the effectiveness of a wingtip vortex attenuating device, referred to as a spline. Vortex penetrations were made with a PA-28 behind a C-54 aircraft with and without wingtip splines attached and the resultant rolling acceleration was measured and related to the roll acceleration capability of the PA-28. Tests were conducted over a range of separation distances from about 5 nautical miles (n. mi.) to less than 1 n. mi. Preliminary results indicate that, with the splines installed, there was a significant reduction in the vortex induced roll acceleration experienced by the PA-28 probe aircraft, and the distance at which the PA-28 roll control became ineffective was reduced from 2.5 n. mi. to 0.6 n. mi., or less. There was a slight increase in approach noise (approximately 4 db) with the splines installed due primarily to the higher engine power used during approach. Although splines significantly reduced the C-54 rate of climb, the rates available with four engines were acceptable for this test program. Splines did not introduce any noticeable change in the handling qualities of the C-54
Measurement of Fruit and Vegetable Intake Incorporating a Diversity, Equity, and Inclusion Lens. Comment on Di Noia, J.; Gellermann, W. Use of the Spectroscopy-Based Veggie Meter® to Objectively Assess Fruit and Vegetable Intake in Low-Income Adults
Disparities in fruit and vegetable intake (FVI) and diet-related diseases exist among low-income and racial/ethnic minority populations [1,2,3,4]. Intervention approaches to eliminate FVI disparities frequently utilize dietary assessment to measure impact. Studies measure FVI in varying ways, but do not fully account for diversity, equity, and inclusion (DEI)
Accelerator Design for the CHESS-U Upgrade
During the summer and fall of 2018 the Cornell High Energy Synchrotron Source
(CHESS) is undergoing an upgrade to increase high-energy flux for x-ray users.
The upgrade requires replacing one-sixth of the Cornell Electron Storage Ring
(CESR), inverting the polarity of half of the CHESS beam lines, and switching
to single-beam on-axis operation. The new sextant is comprised of six
double-bend achromats (DBAs) with combined-function dipole-quadrupoles.
Although the DBA design is widely utilized and well understood, the constraints
for the CESR modifications make the CHESS-U lattice unique. This paper
describes the design objectives, constraints, and implementation for the CESR
accelerator upgrade for CHESS-U
Development and flight tests of vortex-attenuating splines
The ground tests and full-scale flight tests conducted during development of the vortex-attenuating spline are described. The flight tests were conducted using a vortex generating aircraft with and without splines; a second aircraft was used to probe the vortices generated in both cases. The results showed that splines significantly reduced the vortex effects, but resulted in some noise and climb performance penalties on the generating aircraft
Accelerated Bayesian Inference for Molecular Simulations using Local Gaussian Process Surrogate Models
While Bayesian inference is the gold standard for uncertainty quantification
and propagation, its use within physical chemistry encounters formidable
computational barriers. These bottlenecks are magnified for modeling data with
many independent variables, such as X-ray/neutron scattering patterns and
electromagnetic spectra. To address this challenge, we apply a Bayesian
framework accelerated via local Gaussian process (LGP) surrogate models. We
show that the time-complexity of LGPs scales linearly in the number of
independent variables, in stark contrast to the computationally expensive cubic
scaling of conventional Gaussian processes. To illustrate the method, we
trained a LGP surrogate model on the experimental radial distribution function
of liquid neon, and observed a remarkable 288,000-fold speed-up compared to
molecular dynamics with insignificant loss in predictive accuracy. We conclude
that LGPs are robust and efficient surrogate models, poised to expand the
application of Bayesian inference in molecular simulations to a broad spectrum
of ever-advancing experimental data
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