7,773 research outputs found
Constraints on Embeddings
We show that the embedding of either a static or a time dependent maximally
3-symmetric brane with non-zero spatial curvature into a non-compactified
bulk does not yield exponential suppression of the geometry away from
the brane. Implications of this result for brane-localized gravity are
discussed.Comment: RevTeX, 9 pages (updated version v2, conclusions unchanged after
extension to the non-static case
Gravity in Dynamically Generated Dimensions
A theory of gravity in dimensions is dynamically generated from a
theory in dimensions. As an application we show how dynamically coupled
gravity theories can reduce the effective Planck mass.Comment: 7 pages, LaTeX (Revtex
Generation of spin-motion entanglement in a trapped ion using long-wavelength radiation
Applying a magnetic-field gradient to a trapped ion allows long-wavelength radiation to produce a mechanical force on the ion's motion when internal transitions are driven. We demonstrate such a coupling using a single trapped Yb+171 ion and use it to produce entanglement between the spin and motional state, an essential step toward using such a field gradient to implement multiqubit operations
Active galactic nucleus feedback in clusters of galaxies
Observations made during the last ten years with the Chandra X-ray
Observatory have shed much light on the cooling gas in the centers of clusters
of galaxies and the role of active galactic nucleus (AGN) heating. Cooling of
the hot intracluster medium in cluster centers can feed the supermassive black
holes found in the nuclei of the dominant cluster galaxies leading to AGN
outbursts which can reheat the gas, suppressing cooling and large amounts of
star formation. AGN heating can come in the form of shocks, buoyantly rising
bubbles that have been inflated by radio lobes, and the dissipation of sound
waves.Comment: Refereed review article published in Chandra's First Decade of
Discovery Special Feature edition of the Proceedings of the National Academy
of Science
Wave function of the radion in a brane world
We calculate the linearized metric perturbation corresponding to a massless
four-dimensional scalar field, the radion, in a five-dimensional two-brane
model of Randall and Sundrum. In this way we obtain relative strengths of the
radion couplings to matter residing on each of the branes. The results are in
agreement with the analysis of Garriga and Tanaka of gravitational and
Brans--Dicke forces between matter on the branes. We also introduce a model
with infinite fifth dimension and ``almost'' confined graviton, and calculate
the radion properties in that model.Comment: 5 pages revtex, no figures, equation correcte
Computer generated animation and movie production at LARC: A case study
The process of producing computer generated 16mm movies using the MOVIE.BYU software package developed by Brigham Young University and the currently available hardware technology at the Langley Research Center is described. A general overview relates the procedures to a specific application. Details are provided which describe the data used, preparation of a storyboard, key frame generation, the actual animation, title generation, filming, and processing/developing the final product. Problems encountered in each of these areas are identified. Both hardware and software problems are discussed along with proposed solutions and recommendations
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