101,576 research outputs found
Two-dimensional turbulence models
Two-dimensional turbulence models are compared with experimental measurements made using an array of instrumented towers. The spatial correlation coefficient, the two-point spectrum or cross spectrum, and the coherence function are discussed. The prediction techniques in general agree reasonably well with the experimental results. Measurements of the integral length scale however, do not correlate well with the prediction model
Tidal Barrier and the Asymptotic Mass of Proto Gas-Giant Planets
Extrasolar planets found with radial velocity surveys have masses ranging
from several Earth to several Jupiter masses. While mass accretion onto
protoplanetary cores in weak-line T-Tauri disks may eventually be quenched by a
global depletion of gas, such a mechanism is unlikely to have stalled the
growth of some known planetary systems which contain relatively low-mass and
close-in planets along with more massive and longer period companions. Here, we
suggest a potential solution for this conundrum. In general, supersonic infall
of surrounding gas onto a protoplanet is only possible interior to both of its
Bondi and Roche radii. At a critical mass, a protoplanet's Bondi and Roche
radii are equal to the disk thickness. Above this mass, the protoplanets' tidal
perturbation induces the formation of a gap. Although the disk gas may continue
to diffuse into the gap, the azimuthal flux across the protoplanets' Roche lobe
is quenched. Using two different schemes, we present the results of numerical
simulations and analysis to show that the accretion rate increases rapidly with
the ratio of the protoplanet's Roche to Bondi radii or equivalently to the disk
thickness. In regions with low geometric aspect ratios, gas accretion is
quenched with relatively low protoplanetary masses. This effect is important
for determining the gas-giant planets' mass function, the distribution of their
masses within multiple planet systems around solar type stars, and for
suppressing the emergence of gas-giants around low mass stars
In situ transmission electron microscopy study on the epitaxial growth of CoSi2 on Si(111) at temperatures below 150 °C
We report an in situ transmission electron microscopy study on the epitaxial growth of CoSi2 on Si(111) from a 10-nm-thick amorphous mixture of Co and Si in the ratio 1:2 which was formed by codeposition of Co and Si near room temperature. Nuclei of CoSi2 are observed in the as-deposited film. These nuclei are epitaxial and extend through the whole film thickness. Upon annealing, these columnar epitaxial CoSi2 grains grow laterally at temperatures as low as 50 °C. The kinetics of this lateral epitaxial growth was studied at temperatures between 50 and 150 °C. The activation energy of the growth process is 0.8±0.1 eV
Two-Higgs-Doublet-Models and Radiative CP Violation
We discuss the feasibility of spontaneous CP violation being induced by
radiative corrections in 2HDM's. Specifically, we analyze the cases of
gaugino/higgsino effect on MSSM, and a new model with an extra exotic quark
doublet. The new model, while demonstrating well the Georgi-Pais theorem, is
also expected to be phenomenlogically interesting.Comment: 8 pages + cover, 3 figures incoporated, in latex with aipproc.sty
/aipproc.cls, talk given by O.K. at MRST '9
A large-scale one-way quantum computer in an array of coupled cavities
We propose an efficient method to realize a large-scale one-way quantum
computer in a two-dimensional (2D) array of coupled cavities, based on coherent
displacements of an arbitrary state of cavity fields in a closed phase space.
Due to the nontrivial geometric phase shifts accumulating only between the
qubits in nearest-neighbor cavities, a large-scale 2D cluster state can be
created within a short time. We discuss the feasibility of our method for scale
solid-state quantum computationComment: 5 pages, 3 figure
Partonic Effects in Heavy Ion Collisions at RHIC
Effects of partonic interactions in heavy ion collisions at RHIC are studied
in a multiphase transport model (AMPT) that includes both initial partonic and
final hadronic interactions.It is found that a large parton scattering cross
section is needed to understand the measured elliptic flow of pions and
two-pion correlation function.Comment: 10 pages, 5 figures, Workshop on Quark and Hadron Dynamics, Budapest,
Hungary, March 3-7, 200
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