9,798 research outputs found
Application of the Schwinger Oscillator Construct of Angular Momentum to an Interpretation of the Superconducting Transmon Qubit
The Schwinger oscillator construct of angular momentum, applied to the
superconducting transmon and its transmission-line readout, modeled as
capacitvely coupled quantum oscillators, provides a natural and robust
description of a qubit. The construct defines quantum-entangled, two-photon
states that form an angular-momentum-like basis, with symmetry corresponding to
physical conservation of total photon number, with respect to the combined
transmon and readout. This basis provides a convenient starting point from
which to study error-inducing effects of transmon anharmonicity,
surrounding-environment decoherence, and random stray fields on qubit state and
gate operations. Employing a Lindblad master equation to model dissipation to
the surrounding environment, and incorporating the effect of weak transmon
anharmonicity, we present examples of the utility of the construct. First, we
calculate the frequency response associated with exciting the ground state to a
Rabi resonance with the lowest-lying spin-1/2 moment, via a driving external
voltage. Second, we calculate the frequency response between the three lowest
two-photon states, within a ladder-type excitation scheme. The generality of
the Schwinger angular-momentum construct allows it to be applied to other
superconducting charge qubits.Comment: 18 pages, 4 figures, supplement appende
Domino Tatami Covering is NP-complete
A covering with dominoes of a rectilinear region is called \emph{tatami} if
no four dominoes meet at any point. We describe a reduction from planar 3SAT to
Domino Tatami Covering. As a consequence it is NP-complete to decide whether
there is a perfect matching of a graph that meets every 4-cycle, even if the
graph is restricted to be an induced subgraph of the grid-graph. The gadgets
used in the reduction were discovered with the help of a SAT-solver.Comment: 10 pages, accepted at The International Workshop on Combinatorial
Algorithms (IWOCA) 201
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Nevus sebaceus with syringocystadenoma papilliferum, prurigo nodularis, apocrine cystadenoma, basaloid follicular proliferation, and sebaceoma: case report and review of nevus sebaceus-associated conditions
Nevus sebaceus is a benign skin hamartoma of congenital onset that grows during puberty, and in adulthood can develop secondary benign and malignant neoplasms. The most common benign neoplasms occurring in nevus sebaceus are believed to be syringocystadenoma papilliferum, trichilemmoma, and trichoblastoma. A patient with nevus sebaceus developed not only syringocystadenoma papilliferum but also prurigo nodularis within her hamartomatous lesion; multiple biopsies were necessary to establish the diagnoses. Excision of the residual nevus sebaceus also revealed an apocrine cystadenoma, basaloid follicular proliferation, and sebaceoma. Also, it is important to select the appropriate biopsy site and size when evaluating a patient for secondary neoplasms within their nevus sebaceous. Indeed, more than one biopsy may be required if additional diagnoses are suspected
The ionization structure of the Orion nebula: Infrared line observations and models
Observations of the (O III) 52 and 88 micron lines and the (N III) 57 micron line have been made at 6 positions and the (Ne III) 36 micron line at 4 positions in the Orion Nebula to probe its ionization structure. The measurements, made with a -40" diameter beam, were spaced every 45" in a line south from and including the Trapezium. The wavelength of the (Ne III) line was measured to be 36.013 + or - 0.004 micron. Electron densities and abundance ratios of N(++)/O(++) have been calculated and compared to other radio and optical observations. Detailed one component and two component (bar plus halo) spherical models were calculated for exciting stars with effective temperatures of 37 to 40,000K and log g = 4.0 and 4.5. Both the new infrared observations and the visible line measurements of oxygen and nitrogen require T sub eff approx less than 37,000K. However, the double ionized neon requires a model with T sub eff more than or equal to 39,000K, which is more consistent with that inferred from the radio flux or spectral type. These differences in T sub eff are not due to effects of dust on the stellar radiation field, but are probably due to inaccuracies in the assumed stellar spectrum. The observed N(++)/O(++) ratio is almost twice the N(+)/O(+) ratio. The best fit models give N/H = 8.4 x 10 to the -5 power, O/H = 4.0 x 10 to the -4 power, and Ne/H = 1.3 x 10 to the -4 power. Thus neon and nitrogen are approximately solar, but oxygen is half solar in abundance. From the infrared O(++) lines it is concluded that the ionization bar results from an increase in column depth rather than from a local density enhancement
Investigation of LANDSAT follow-on thematic mapper spatial, radiometric and spectral resolution
The author has identified the following significant results. Fine resolution M7 multispectral scanner data collected during the Corn Blight Watch Experiment in 1971 served as the basis for this study. Different locations and times of year were studied. Definite improvement using 30-40 meter spatial resolution over present LANDSAT 1 resolution and over 50-60 meter resolution was observed, using crop area mensuration as the measure. Simulation studies carried out to extrapolate the empirical results to a range of field size distributions confirmed this effect, showing the improvement to be most pronounced for field sizes of 1-4 hectares. Radiometric sensitivity study showed significant degradation of crop classification accuracy immediately upon relaxation from the nominally specified values of 0.5% noise equivalent reflectance. This was especially the case for data which were spectrally similar such as that collected early in the growing season and also when attempting to accomplish crop stress detection
Doctors at Risk: A Problem As Viewed by Decision Analysis
The authors closely analyze a case in which a Peer Review Organization cited a physician for treatment with potential for significant adverse effect. They also critique the regulatory scheme under which peer review occurs and conclude that such regulation interferes with physicians\u27 primary obligations, fails to encourage cost-effective behavior and may decrease the quality of medical care
Recognition map analysis and crop acreage estimation using Skylab EREP data
There are no author-identified significant results in this report
Quantity and Price Adjustment in Long-Term Contracts: A Case Study of Petroleum Coke
Much economic activity takes place within a framework of complex, long-term contracts. While economists have shown increased interest in these contracts, surprisingly little is known about them, or, indeed, about how to analyze the contracting activity of private economic actors. A case study of the actual contracts used in one industry could provide sorely needed data about the way in which reasonably clever businessmen and lawyers cope with problems scholars might consider intractable. In this article, we provide such an analysis of contracts concerning a particular product – petroleum coke. We focus on the problems of quantity and price adjustment. We do not deal, except in passing, with the question of why the parties chose long-term contracts rather than short-term agreements or vertical integration by contract rather than by ownership
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