31,734 research outputs found
Staggered Superconductivity in UPt: A New Phenomenological Approach
We present a new Ginzburg-Landau theory for superconductivity in UPt,
based upon a multicomponent order parameter transforming under an irreducible
space group representation; the phase is staggered in real space. Our model can
explain the phase diagram including the tetracritical point for all
field directions. We motivate this unconventional superconducting state in
terms of odd-in-time-reversal pairing that may arise in one- or two-channel
Kondo models, and suggest experimental tests.Comment: 12 pages, 3 postscript figures are appended as a uuencoded file,
RevTeX 3.
Saturn S-IB stage Final static test report, stage S-IB-2
Acceptance test firing of Saturn flight stage S-IB-
Saturn S-IB stage Final static test report, stage S-IB-4
Acceptance static test firing data for Saturn flight stage S-IB-
The 24-Cell and Calabi-Yau Threefolds with Hodge Numbers (1,1)
Calabi-Yau threefolds with h^11(X)=h^21(X)=1 are constructed as free
quotients of a hypersurface in the ambient toric variety defined by the
24-cell. Their fundamental groups are SL(2,3), a semidirect product of Z_3 and
Z_8, and Z_3 x Q_8.Comment: 22 pages, 3 figures, 3 table
Central Exclusive Di-jet Production at the Tevatron
We perform a phenomenological analysis of dijet production in double pomeron
exchange at the Tevatron. We find that the CDF Run I results do not rule out
the presence of an exclusive dijet component, as predicted by Khoze, Martin and
Ryskin (KMR). With the high statistics CDF Run II data, we predict that an
exclusive component at the level predicted by KMR may be visible, although the
observation will depend on accurate modelling of the inclusive double pomeron
exchange process. We also compare to the predictions of the DPEMC Monte Carlo,
which contains a non-perturbative model for the central exclusive process. We
show that the perturbative model of KMR gives different predictions for the
di-jet ET dependence in the high di-jet mass fraction region than
non-perturbative models.Comment: 17 pages, 15 figure
Assembly and analysis of fragmentation data for liquid propellant vessels
Fragmentation data was assembled and analyzed for exploding liquid propellant vessels. These data were to be retrieved from reports of tests and accidents, including measurements or estimates of blast yield, etc. A significant amount of data was retrieved from a series of tests conducted for measurement of blast and fireball effects of liquid propellant explosions (Project PYRO), a few well-documented accident reports, and a series of tests to determine auto-ignition properties of mixing liquid propellants. The data were reduced and fitted to various statistical functions. Comparisons were made with methods of prediction for blast yield, initial fragment velocities, and fragment range. Reasonably good correlation was achieved. Methods presented in the report allow prediction of fragment patterns, given type and quantity of propellant, type of accident, and time of propellant mixing
Application of remote sensing technology to land evaluation, planning utilization of land resources, and assessment of westland habitat in eastern South Dakota, parts 1 and 2
The author has identified the following significant results. LANDSAT fulfilled the requirements for general soils and land use information. RB-57 imagery was required to provide the information and detail needed for mapping soils for land evaluation. Soils maps for land evaluation were provided on clear mylar at the scale of the county highway map to aid users in locating mapping units. Resulting mapped data were computer processed to provided a series of interpretive maps (land value, limitations to development, etc.) and area summaries for the users
The Nikolaevskiy equation with dispersion
The Nikolaevskiy equation was originally proposed as a model for seismic
waves and is also a model for a wide variety of systems incorporating a
neutral, Goldstone mode, including electroconvection and reaction-diffusion
systems. It is known to exhibit chaotic dynamics at the onset of pattern
formation, at least when the dispersive terms in the equation are suppressed,
as is commonly the practice in previous analyses. In this paper, the effects of
reinstating the dispersive terms are examined. It is shown that such terms can
stabilise some of the spatially periodic traveling waves; this allows us to
study the loss of stability and transition to chaos of the waves. The secondary
stability diagram (Busse balloon) for the traveling waves can be remarkably
complicated.Comment: 24 pages; accepted for publication in Phys. Rev.
Large Interstellar Polarisation Survey II. UV/optical study of cloud-to-cloud variations of dust in the diffuse ISM
It is well known that the dust properties of the diffuse interstellar medium
exhibit variations towards different sight-lines on a large scale. We have
investigated the variability of the dust characteristics on a small scale, and
from cloud-to-cloud. We use low-resolution spectro-polarimetric data obtained
in the context of the Large Interstellar Polarisation Survey (LIPS) towards 59
sight-lines in the Southern Hemisphere, and we fit these data using a dust
model composed of silicate and carbon particles with sizes from the molecular
to the sub-micrometre domain. Large (> 6 nm) silicates of prolate shape account
for the observed polarisation. For 32 sight-lines we complement our data set
with UVES archive high-resolution spectra, which enable us to establish the
presence of single-cloud or multiple-clouds towards individual sight-lines. We
find that the majority of these 35 sight-lines intersect two or more clouds,
while eight of them are dominated by a single absorbing cloud. We confirm
several correlations between extinction and parameters of the Serkowski law
with dust parameters, but we also find previously undetected correlations
between these parameters that are valid only in single-cloud sight-lines. We
find that interstellar polarisation from multiple-clouds is smaller than from
single-cloud sight-lines, showing that the presence of a second or more clouds
depolarises the incoming radiation. We find large variations of the dust
characteristics from cloud-to-cloud. However, when we average a sufficiently
large number of clouds in single-cloud or multiple-cloud sight-lines, we always
retrieve similar mean dust parameters. The typical dust abundances of the
single-cloud cases are [C]/[H] = 92 ppm and [Si]/[H] = 20 ppm.Comment: A&A accepte
Statistics of quantum transmission in one dimension with broad disorder
We study the statistics of quantum transmission through a one-dimensional
disordered system modelled by a sequence of independent scattering units. Each
unit is characterized by its length and by its action, which is proportional to
the logarithm of the transmission probability through this unit. Unit actions
and lengths are independent random variables, with a common distribution that
is either narrow or broad. This investigation is motivated by results on
disordered systems with non-stationary random potentials whose fluctuations
grow with distance.
In the statistical ensemble at fixed total sample length four phases can be
distinguished, according to the values of the indices characterizing the
distribution of the unit actions and lengths. The sample action, which is
proportional to the logarithm of the conductance across the sample, is found to
obey a fluctuating scaling law, and therefore to be non-self-averaging, in
three of the four phases. According to the values of the two above mentioned
indices, the sample action may typically grow less rapidly than linearly with
the sample length (underlocalization), more rapidly than linearly
(superlocalization), or linearly but with non-trivial sample-to-sample
fluctuations (fluctuating localization).Comment: 26 pages, 4 figures, 1 tabl
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