4,915 research outputs found

    Quantum Cryptography with Orthogonal States?

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    This is a Comment on Phys Rev Lett 75 (1995) 1239, by Goldenberg and VaidmanComment: 3 pages, LaTeX, 1 figure on separate page Final version in Phys Rev Lett 77 (1996) 326

    The History of the Mysterious Eclipses of KH 15D: Asiago Observatory, 1967-1982

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    We are gathering archival observations to determine the photometric history of the unique and unexplained eclipses of the pre-main-sequence star KH 15D. Here we present a light curve from 1967-1982, based on photographic plates from Asiago Observatory. During this time, the system alternated periodically between bright and faint states, as observed today. However, the bright state was 0.9 mag brighter than the modern value, and the fractional variation between bright and faint states (Delta I = 0.7 mag) was smaller than observed today (3.5 mag). A possible explanation for these findings is that the system contains a second star that was previously blended with the eclipsing star, but is now completely obscured.Comment: Accepted to AJ. 24 pages, 10 figures, 2 tables. v2: Phase error corrected in figures 8 and 1

    The Wage Rate Effects of Occupational Labor Market Tightness

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    Using the May 1981 Current Population Survey tape and occupational labor market conditions data from the Bureau of Labor Statistics, this study tests (1) whether excess demand for labor is directly related to hourly earnings and (2) what effect, if any, controlling for excess demand may have on the estimated gender differential. The data support a direct effect between excess demand and wage rates. With regard to gender effects, females were disproportionately found to be in occupations with more excess demand (in the disequilibrium sense). Though the measured male premium was larger when controlling for labor market conditions, the increase was neither appreciable nor statistically significant.

    Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra

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    We present a technique to extract radial velocity measurements from echelle spectrograph observations of rapidly rotating stars (Vsini50V\sin{i} \gtrsim 50 km s1^{-1}). This type of measurement is difficult because the line widths of such stars are often comparable to the width of a single echelle order. To compensate for the scarcity of lines and Doppler information content, we have developed a process that forward-models the observations, fitting the radial velocity shift of the star for all echelle orders simultaneously with the echelle blaze function. We use our technique to extract radial velocity measurements from a sample of rapidly rotating A- and B-type stars used as calibrator stars observed by the California Planet Survey observations. We measure absolute radial velocities with a precision ranging from 0.5-2.0 km s1^{-1} per epoch for more than 100 A- and B-type stars. In our sample of 10 well-sampled stars with radial velocity scatter in excess of their measurement uncertainties, three of these are single-lined binaries with long observational baselines. From this subsample, we present detections of two previously unknown spectroscopic binaries and one known astrometric system. Our technique will be useful in measuring or placing upper limits on the masses of sub-stellar companions discovered by wide-field transit surveys, and conducting future spectroscopic binarity surveys and Galactic space-motion studies of massive and/or young, rapidly-rotating stars.Comment: Accepted to ApJ

    Optimal distinction between non-orthogonal quantum states

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    Given a finite set of linearly independent quantum states, an observer who examines a single quantum system may sometimes identify its state with certainty. However, unless these quantum states are orthogonal, there is a finite probability of failure. A complete solution is given to the problem of optimal distinction of three states, having arbitrary prior probabilities and arbitrary detection values. A generalization to more than three states is outlined.Comment: 9 pages LaTeX, one PostScript figure on separate pag

    Diffusional Relaxation in Random Sequential Deposition

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    The effect of diffusional relaxation on the random sequential deposition process is studied in the limit of fast deposition. Expression for the coverage as a function of time are analytically derived for both the short-time and long-time regimes. These results are tested and compared with numerical simulations.Comment: 9 pages + 2 figure
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