5,582 research outputs found
Generalized keesom potential
Field theoretic approach for generalization of expressions for adiabatic interaction between two rotating dipolar system
Development of phase-change coatings for use as variable thermal control surfaces Final report
Phase change coatings for use as variable thermal control surface
Development of phase-change coatings for use as variable thermal control surfaces Final report, 8 Mar. 1967 - 8 Mar. 1968
Development of phase-change coatings for thermal control of spacecraft surface
Uniqueness of Current Cosmic Acceleration
One of the strongest arguments against the cosmological constant as an
explanation of the current epoch of accelerated cosmic expansion is the
existence of an earlier, dynamical acceleration, i.e. inflation. We examine the
likelihood that acceleration is an occasional phenomenon, putting stringent
limits on the length of any accelerating epoch between recombination and the
recent acceleration; such an epoch must last less than 0.05 e-fold (at z>2) or
the matter power spectrum is modified by more than 20%.Comment: 6 pages, 5 figures; v2 corrected typo in Eq.
Single stage experimental evaluation of slotted rotor and stator blading. Part I - Analysis and design
Analysis and design of slotted rotor and stator blading for application to compressors in advanced airbreathing propulsion system
The neighborhood of Saturdays : memories of a multi-ethnic community on Indianapolis' south side
Parametric resonance for antineutrino conversions using LSND best-fit results with a 3+1 flavor scheme
An analytical solution to a parametric resonance effect for antineutrinos in
a 3+1 flavor (active+sterile) scheme using multiple non-adiabatic density
shifts is presented. We derive the conditions for a full flavor conversion for
antineutrino oscillations
under the assumption that LSND best-fits for the mixing
parameters are valid in a short-baseline accelerator experiment. We show that
the parametric resonance effect can be exploited to increase the effective
antineutrino oscillation length by a factor of 10-40, thus sustaining a high
oscillation probability for a much longer period of time than in the vacuum
scenario. We propose a realistic experimental setup that could probe for this
effect which leaves a signature in terms of a specific oscillation probability
profile. Moreover, since the parametric resonance effect is valid in any 2 or
1+1 flavor approximation, our results could be suggestive for future
short-baseline accelerator neutrino detection experiments.Comment: 6 pages, 4 figure
Systematic Errors in Future Weak Lensing Surveys: Requirements and Prospects for Self-Calibration
We study the impact of systematic errors on planned weak lensing surveys and
compute the requirements on their contributions so that they are not a dominant
source of the cosmological parameter error budget. The generic types of error
we consider are multiplicative and additive errors in measurements of shear, as
well as photometric redshift errors. In general, more powerful surveys have
stronger systematic requirements. For example, for a SNAP-type survey the
multiplicative error in shear needs to be smaller than 1%(fsky/0.025)^{-1/2} of
the mean shear in any given redshift bin, while the centroids of photometric
redshift bins need to be known to better than 0.003(fsky/0.025)^{-1/2}. With
about a factor of two degradation in cosmological parameter errors, future
surveys can enter a self-calibration regime, where the mean systematic biases
are self-consistently determined from the survey and only higher-order moments
of the systematics contribute. Interestingly, once the power spectrum
measurements are combined with the bispectrum, the self-calibration regime in
the variation of the equation of state of dark energy w_a is attained with only
a 20-30% error degradation.Comment: 20 pages, 9 figures, to be submitted to MNRAS. Comments are welcom
Horizontal Merger between Two Newspapers Involving Potential Competition Prohibited under Section 7 of the Clayton Act
What will anisotropies in the clustering pattern in redshifted 21 cm maps tell us?
The clustering pattern in high redshift HI maps is expected to be anisotropic
due to two distinct reasons, the
Alcock-Paczynski effect and the peculiar velocities, both of which are
sensitive to the cosmological parameters. The signal is also expected to be
sensitive to the details of the HI distribution at the epoch when the radiation
originated. We use simple models for the HI distribution at the epoch of
reionizaation and the post-reionization era to investigate exactly what we hope
to learn from future observations of the anisotropy pattern in HI maps. We find
that such observations will probably tell us more about the HI distribution
than about the background cosmological model. Assuming that reionization can be
described by spherical, ionized bubbles all of the same size with their centers
possibly being biased with respect to the dark matter, we find that the
anisotropy pattern at small angles is expected to have a bump at the
characteristic angular size of the individual bubbles whereas the large scale
anisotropy pattern will reflect the size and the bias of the bubbles. The
anisotropy also depends on the background cosmological parameters, but the
dependence is much weaker. Under the assumption that the HI in the
post-reionization era traces the dark matter with a possible bias, we find that
changing the bias and changing the background cosmology has similar effects on
the anisotropy pattern. Combining observations of the anisotropy with
independent estimates of the bias, possibly from the bi-spectrum, may allow
these observations to constrain cosmological parameters.Comment: Minor changes, Accepted to MNRA
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