1,562 research outputs found
Turbulence and turbulent mixing in natural fluids
Turbulence and turbulent mixing in natural fluids begins with big bang
turbulence powered by spinning combustible combinations of Planck particles and
Planck antiparticles. Particle prograde accretions on a spinning pair releases
42% of the particle rest mass energy to produce more fuel for turbulent
combustion. Negative viscous stresses and negative turbulence stresses work
against gravity, extracting mass-energy and space-time from the vacuum.
Turbulence mixes cooling temperatures until strong-force viscous stresses
freeze out turbulent mixing patterns as the first fossil turbulence. Cosmic
microwave background temperature anisotropies show big bang turbulence fossils
along with fossils of weak plasma turbulence triggered as plasma photon-viscous
forces permit gravitational fragmentation on supercluster to galaxy mass
scales. Turbulent morphologies and viscous-turbulent lengths appear as linear
gas-proto-galaxy-clusters in the Hubble ultra-deep-field at z~7. Proto-galaxies
fragment into Jeans-mass-clumps of primordial-gas-planets at decoupling: the
dark matter of galaxies. Shortly after the plasma to gas transition,
planet-mergers produce stars that explode on overfeeding to fertilize and
distribute the first life.Comment: 23 pages 12 figures, Turbulent Mixing and Beyond 2009 International
Center for Theoretical Physics conference, Trieste, Italy. Revision according
to Referee comments. Accepted for Physica Scripta Topical Issue to be
published in 201
Hamiltonian Formulation of Two Body Problem in Wheeler-Feynman electrodynamics
A Hamiltonian formulation for the classical problem of electromagnetic
interaction of two charged relativistic particles is found.Comment: 22 pages, 8 Uuencoded Postscript figure
A new technique for oral endotracheal airway access in rabbits under fluoroscopic control: an easy way for drug administration in chronic experiments
A young man with position-dependent erectile dysfunction: diagnostic work-up and interventional therapy of an arteriovenous malformation
Global embedding of the Kerr black hole event horizon into hyperbolic 3-space
An explicit global and unique isometric embedding into hyperbolic 3-space,
H^3, of an axi-symmetric 2-surface with Gaussian curvature bounded below is
given. In particular, this allows the embedding into H^3 of surfaces of
revolution having negative, but finite, Gaussian curvature at smooth fixed
points of the U(1) isometry. As an example, we exhibit the global embedding of
the Kerr-Newman event horizon into H^3, for arbitrary values of the angular
momentum. For this example, considering a quotient of H^3 by the Picard group,
we show that the hyperbolic embedding fits in a fundamental domain of the group
up to a slightly larger value of the angular momentum than the limit for which
a global embedding into Euclidean 3-space is possible. An embedding of the
double-Kerr event horizon is also presented, as an example of an embedding
which cannot be made global.Comment: 16 pages, 13 figure
The Relation between Physical and Gravitational Geometry
The appearance of two geometries in one and the same gravitational theory is
familiar. Usually, as in the Brans-Dicke theory or in string theory, these are
conformally related Riemannian geometries. Is this the most general relation
between the two geometries allowed by physics ? We study this question by
supposing that the physical geometry on which matter dynamics take place could
be Finslerian rather than just Riemannian. An appeal to the weak equivalence
principle and causality then leads us the conclusion that the Finsler geometry
has to reduce to a Riemann geometry whose metric - the physical metric - is
related to the gravitational metric by a generalization of the conformal
transformation.Comment: 15 pages, Te
Umbral Calculus, Discretization, and Quantum Mechanics on a Lattice
`Umbral calculus' deals with representations of the canonical commutation
relations. We present a short exposition of it and discuss how this calculus
can be used to discretize continuum models and to construct representations of
Lie algebras on a lattice. Related ideas appeared in recent publications and we
show that the examples treated there are special cases of umbral calculus. This
observation then suggests various generalizations of these examples. A special
umbral representation of the canonical commutation relations given in terms of
the position and momentum operator on a lattice is investigated in detail.Comment: 19 pages, Late
Partonic description of a supersymmetric p-brane
We consider supersymmetric extensions of a recently proposed partonic
description of a bosonic p-brane which reformulates the Nambu-Goto action as an
interacting multi-particle action with Filippov-Lie algebra gauge symmetry. We
construct a worldline supersymmetric action by postulating, among others, a
p-form fermion. Demanding a local worldline supersymmetry rather than the full
worldvolume supersymmetry, we circumvent a known no-go theorem against the
construction of a Ramond-Neveu-Schwarz supersymmetric action for a p-brane of
p>1. We also derive a spacetime supersymmetric Green-Schwarz extension from the
preexisting kappa-symmetric action.Comment: 1+16 pages, no figure; References added and Concluding section
expanded. Final version to appear in JHE
Opening the Treasure Chest: A Newborn Star Cluster Emerges from its Dust Pillar in Carina
We present detailed observations of the Treasure Chest, a compact nebula at
the head of a dust pillar in the southern Carina nebula. This object is of
interest because it is an example of a dense young cluster containing at least
one massive star, the formation of which may have been triggered by feedback
from the very massive stars in the Carina nebula, and possibly Eta Car itself.
We investigate both the nebular and stellar content of the object. Near-IR
emission-line images reveal a cavity inside the head of the dust pillar, which
contains a dense cluster of young stars, while the observed spectrum of the
nebula is consistent with an H II region ionized by an O9.5 V star. After
subtracting contamination of field stars within the Carina nebula itself, we
compare the cluster's color magnitude diagram with pre-main-sequence isochrones
to derive a likely cluster age less than about 0.1 Myr. This is in reasonable
agreement with the dynamical age of a few times 10^4 yr for the expanding
nebular cavity, indicating extreme youth. Stars in the Treasure Chest cluster
are highly reddened, with extinction values as large as A_V=50. Two-thirds of
cluster members show strong infrared excess colors indicative of circumstellar
disks, which may prove to be among the highest fraction yet seen for a young
cluster. All evidence suggests that the Treaure Chest is an extremely young
cluster that is just now breaking out of its natal cloud into the surrounding
massive star forming region, and is a good target for more detailed study.Comment: 23 pages, 10 figs, 4 color fig
Gravitational Microlensing as a probe of the Electron Scattering Region in Q2237+0305
Recent observations have provided strong evidence for the presence of an
Electron Scattering Region (ESR) within the central regions of AGNs. This is
responsible for reprocessing emission from the accretion disk into polarised
radiation. The geometry of this scattering region is, however, poorly
constrained. In this paper, we consider the influence of gravitational
microlensing on polarised emission from the ESR in the quadruply imaged quasar,
Q2237+0305, demonstrating how correlated features in the resultant light curve
variations can determine both the size and orientation of the scattering
region. This signal is due to differential magnification between
perpendicularly polarised views of the ESR, and is clearest for a small ESR
width and a large ESR radius. Cross- and auto-correlation measures appear to be
independent of lens image shear and convergence parameters, making it ideal to
investigate ESR features. As with many microlensing experiments, the time-scale
for variability, being of order decades to centuries, is impractically long.
However, with a polarization filter oriented appropriately with respect to the
path that the quasar takes across the caustic structure, the ESR diameter and
radius can be estimated from the auto- and cross-correlation of polarized light
curves on much shorter time-scales.Comment: 11 pages, 12 figures, 1 table, accepted for MNRA
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