3,432 research outputs found
The DE magnetometer preprocessor users guide
A users guide for the Dynamics Explorer magnetometer preprocessor computer program is provided. This program is written in Xerox Extended FORTRAN IV and is used to process telemetry data in order to provide data files for use in analysis programs. This preprocessor is designed to operate on the Sigma 9 and the IBM 4341
Inhomogeneous non-Gaussianity
We propose a method to probe higher-order correlators of the primordial
density field through the inhomogeneity of local non-Gaussian parameters, such
as f_NL, measured within smaller patches of the sky. Correlators between
n-point functions measured in one patch of the sky and k-point functions
measured in another patch depend upon the (n+k)-point functions over the entire
sky. The inhomogeneity of non-Gaussian parameters may be a feasible way to
detect or constrain higher-order correlators in local models of
non-Gaussianity, as well as to distinguish between single and multiple-source
scenarios for generating the primordial density perturbation, and more
generally to probe the details of inflationary physics.Comment: 16 pages, 2 figures; v2: Minor changes and references added. Matches
the published versio
Macroscopic quantum computation using Bose-Einstein condensates
Quantum computation using qubits made of two component Bose-Einstein
condensates (BECs) is analysed. The use of BECs allows for an increase of
energy scales via bosonic enhancement, resulting in gate operations that can be
performed at a macroscopically large energy scale. The large energy scale of
the gate operations results in quantum algorithms that may be executed at a
time reduced by a factor of N, where N is the number of bosons per qubit. The
encoding of the qubits allows for no intrinsic penalty on decoherence times. We
illustrate the scheme by an application to Deutsch's and Grover's algorithms.Comment: 10 pages, 3 figure
Investigation of foamed metals for application on space capsules annual report, 29 jun. 1963 - 15 aug. 1964
Foamed metal development for space capsules - brazing, variable density beam, thermal testing, mechanical tests, and machinin
Influence of reheating on the trispectrum and its scale dependence
We study the evolution of the non-linear curvature perturbation during perturbative reheating, and hence how observables evolve to their final values which we may compare against observations. Our study includes the evolution of the two trispectrum parameters, \gnl and \taunl, as well as the scale dependence of both \fnl and \taunl. In general the evolution is significant and must be taken into account, which means that models of multifield inflation cannot be compared to observations without specifying how the subsequent reheating takes place. If the trispectrum is large at the end of inflation, it normally remains large at the end of reheating. In the classes of models we study, it is very hard to generate \taunl\gg\fnl^2, regardless of the decay rates of the fields. Similarly, for the classes of models in which \gnl\simeq\taunl during slow--roll inflation, we find the relation typically remains valid during reheating. Therefore it is possible to observationally test such classes of models without specifying the parameters of reheating, even though the individual observables are sensitive to the details of reheating. It is hard to generate an observably large \gnl however. The runnings, \nfnl and \ntaunl, tend to satisfy a consistency relation \ntaunl=(3/2)\nfnl, but are in general too small to be observed for the class of models considered regardless of reheating timescale
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