2,664 research outputs found

    Mapping X-ray heliometer for Orbiting Solar Observatory-8

    Get PDF
    An instrument combining mechanical collimators and proportional counter detectors was designed to record solar X-rays with energies of 2-30 keV with good temperal, spectral, and spatial resolution. The overall operation of the instrument is described to the degree needed by personnel who interact with the experimenter during SC/experiment interfacing, experiment testing, observatory integration and testing, and pre/post launch data processing. The general layout of the instrument is given along with a summary of the instrument characteristics

    Fundamental length in quantum theories with PT-symmetric Hamiltonians

    Full text link
    The direct observability of coordinates x is often lost in PT-symmetric quantum theories. A manifestly non-local Hilbert-space metric Θ\Theta enters the double-integral normalization of wave functions ψ(x)\psi(x) there. In the context of scattering, the (necessary) return to the asymptotically fully local metric has been shown feasible, for certain family of PT-symmetric toy Hamiltonians H at least, in paper I (M. Znojil, Phys. Rev. D 78 (2008) 025026). Now we show that in a confined-motion dynamical regime the same toy model proves also suitable for an explicit control of the measure or width θ\theta of its non-locality. For this purpose each H is assigned here, constructively, the complete menu of its hermitizing metrics Θ=Θθ\Theta=\Theta_\theta distinguished by their optional "fundamental lengths" θ∈(0,∞)\theta\in (0,\infty). The local metric of paper I recurs at θ=0\theta=0 while the most popular CPT-symmetric hermitization proves long-ranged, with θ=∞\theta=\infty.Comment: 31 pp, 3 figure

    Experimental study of spectral and spatial distribution of solar X-rays

    Get PDF
    The study of the physical conditions within the solar corona and the development of instrumentation and technical expertise necessary for advanced studies of solar X-ray emission are reported. Details are given on the Aerobee-borne-X-ray spectrometer/monochromator and also on the observing program. Preliminary discussions of some results are presented and include studies of helium-like line emission, mapping O(VII) and Ne(IX) lines, survey of O(VII) and Ne(IX) lines, study of plage regions and small flares, and analysis of line emission from individual active regions. It is concluded that the use of large-area collimated Bragg spectrometers to scan narrow wavelength intervals and the capability of the SPARCS pointing control to execute a complex observing program are established

    Gegenbauer-solvable quantum chain model

    Full text link
    In an innovative inverse-problem construction the measured, experimental energies E1E_1, E2E_2, ...ENE_N of a quantum bound-state system are assumed fitted by an N-plet of zeros of a classical orthogonal polynomial fN(E)f_N(E). We reconstruct the underlying Hamiltonian HH (in the most elementary nearest-neighbor-interaction form) and the underlying Hilbert space H{\cal H} of states (the rich menu of non-equivalent inner products is offered). The Gegenbauer's ultraspherical polynomials fn(x)=Cnα(x)f_n(x)=C_n^\alpha(x) are chosen for the detailed illustration of technicalities.Comment: 29 pp., 1 fi

    Simple manipulation of a microwave dressed-state ion qubit

    Get PDF
    Many schemes for implementing quantum information processing require that the atomic states used have a non-zero magnetic moment, however such magnetically sensitive states of an atom are vulnerable to decoherence due to fluctuating magnetic fields. Dressing an atom with an external field is a powerful method of reducing such decoherence [N. Timoney et al., Nature 476, 185], even if the states being dressed are strongly coupled to the environment. We introduce an experimentally simpler method of manipulating such a dressed-state qubit, which allows the implementation of general rotations of the qubit, and demonstrate this method using a trapped ytterbium ion

    Scalable simultaneous multi-qubit readout with 99.99% single-shot fidelity

    Full text link
    We describe single-shot readout of a trapped-ion multi-qubit register using space and time-resolved camera detection. For a single qubit we measure 0.9(3)x10^{-4} readout error in 400us exposure time, limited by the qubit's decay lifetime. For a four-qubit register (a "qunybble") we measure an additional error of only 0.1(1)x10^{-4} per qubit, despite the presence of 4% optical cross-talk between neighbouring qubits. A study of the cross-talk indicates that the method would scale with negligible loss of fidelity to ~10000 qubits at a density <~1 qubit/um^2, with a readout time ~1us/qubit.Comment: 4 pages, 3 figures; simulations added to fig.3, with some further text and figure revisions. Main results unchanged

    Universality in the merging dynamics of parametric active contours: a study in MRI-based lung segmentation

    Full text link
    Measurement of lung ventilation is one of the most reliable techniques of diagnosing pulmonary diseases. The time consuming and bias prone traditional methods using hyperpolarized H3{}^{3}He and 1{}^{1}H magnetic resonance imageries have recently been improved by an automated technique based on multiple active contour evolution. Mapping results from an equivalent thermodynamic model, here we analyse the fundamental dynamics orchestrating the active contour (AC) method. We show that the numerical method is inherently connected to the universal scaling behavior of a classical nucleation-like dynamics. The favorable comparison of the exponent values with the theoretical model render further credentials to our claim.Comment: 4 pages, 4 figure

    The Lockheed OSO-8 program. Analysis of data from the mapping X-ray heliometer experiment

    Get PDF
    The final report describes the extent of the analysis effort, and other activities associated with the preservation and documentation of the data set are described. The main scientific results, which are related to the behavior of individual solar activity regions in the energy band 1.5 - 15 keV, are summarized, and a complete bibliography of publications and presentations is given. Copies of key articles are also provided

    An Unusual Combination of Neurological Manifestations and Sudden Vision Loss in a Child with Familial Hyperphosphatemic Tumoral Calcinosis

    Get PDF
    Hyperphosphatemia in the absence of renal failure is an unusual occurrence, particularly in children, but is a common primary feature of familial hyperphosphatemic tumor calcinosis. We report a child with hyperphosphatemia who presented with multiple episodes of neurologic dysfunction involving lower motor neuron facial nerve palsy along with sequential visual loss. He also had an episode of stroke. There was an extensive metastatic calcification of soft tissue and vasculature. Hyperphosphatemia with normal serum alkaline phosphatase, calcium, parathyroid hormone, and renal function was noted. He was managed with hemodialysis and sevelamer (3 months) without much success in reducing serum phosphate level, requiring continuous ambulatory peritoneal dialysis (3 years). Intact fibroblast growth factor 23 (FGF23) was undetectable, with C-terminal FGF23 fragments significantly elevated (2575 RU/ml, normal A (p.N162K) mutation in FGF23 exon 3, confirming the diagnoses of primary FGF23 deficiency, the first case to be reported from India
    • …
    corecore