36,783 research outputs found
Quasi-matter bounce and inflation in the light of the CSL model
The Continuous Spontaneous Localization (CSL) model has been proposed as a
possible solution to the quantum measurement problem by modifying the
Schr\"{o}dinger equation. In this work, we apply the CSL model to two
cosmological models of the early Universe: the matter bounce scenario and slow
roll inflation. In particular, we focus on the generation of the classical
primordial inhomogeneities and anisotropies that arise from the dynamical
evolution, provided by the CSL mechanism, of the quantum state associated to
the quantum fields. In each case, we obtained a prediction for the shape and
the parameters characterizing the primordial spectra (scalar and tensor), i.e.
the amplitude, the spectral index and the tensor-to-scalar ratio. We found that
there exist CSL parameter values, allowed by other non-cosmological
experiments, for which our predictions for the angular power spectrum of the
CMB temperature anisotropy are consistent with the best fit canonical model to
the latest data released by the Planck Collaboration.Comment: 27 pages, including 6 figures, 2 tables and one Appendix. Final
version. Accepted in EPJ
Quasi-Langmuir-Blodgett Thin Film Deposition of Carbon Nanotubes
The handling and manipulation of carbon nanotubes continues to be a challenge
to those interested in the application potential of these promising materials.
To this end, we have developed a method to deposit pure nanotube films over
large flat areas on substrates of arbitrary composition. The method bears some
resemblance to the Langmuir-Blodgett deposition method used to lay down thin
organic layers. We show that this redeposition technique causes no major
changes in the films' microstructure and that they retain the electronic
properties of as-deposited film laid down on an alumina membrane.Comment: 3 pages, 3 figures, submitted Journal of Applied Physic
The Gattaca Model: Should the Military Be Allowed to Select Its Elite Forces Based upon One\u27s DNA
On competitive discrete systems in the plane. I. Invariant Manifolds
Let be a competitive map on a rectangular region . The main results of this paper give conditions which guarantee
the existence of an invariant curve , which is the graph of a continuous
increasing function, emanating from a fixed point . We show that
is a subset of the basin of attraction of and that the set consisting
of the endpoints of the curve in the interior of is forward invariant.
The main results can be used to give an accurate picture of the basins of
attraction for many competitive maps.
We then apply the main results of this paper along with other techniques to
determine a near complete picture of the qualitative behavior for the following
two rational systems in the plane.
with
and arbitrary nonnegative initial conditions so
that the denominator is never zero.
with
and arbitrary nonnegative initial conditions.Comment: arXiv admin note: text overlap with arXiv:0905.1772 by other author
A modified semi--implict Euler-Maruyama Scheme for finite element discretization of SPDEs with additive noise
We consider the numerical approximation of a general second order
semi--linear parabolic stochastic partial differential equation (SPDE) driven
by additive space-time noise. We introduce a new modified scheme using a linear
functional of the noise with a semi--implicit Euler--Maruyama method in time
and in space we analyse a finite element method (although extension to finite
differences or finite volumes would be possible). We prove convergence in the
root mean square norm for a diffusion reaction equation and diffusion
advection reaction equation. We present numerical results for a linear reaction
diffusion equation in two dimensions as well as a nonlinear example of
two-dimensional stochastic advection diffusion reaction equation. We see from
both the analysis and numerics that the proposed scheme has better convergence
properties than the standard semi--implicit Euler--Maruyama method
Cointegration and the joint confirmation hypothesis
Recent papers by Charemza and Syczewska (1998) and Carrion, Sansó and Ortuño (2001) focused on the joint use of unit root and stationarity tests. In this paper, the discussion is extended to the case of cointegration. Critical values for testing the joint confirmation hypothesis of no cointegration are computed and a small Monte Carlo experiment evaluates the relative performance of this procedure.Cointegration; Joint confirmation hypothesis; Monte Carlo simulations.
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