1,884 research outputs found
Some remarks on the observational constraints on the self-interacting scalar field model for dark energy
The dark energy component of the cosmic budget is represented by a
self-interacting scalar field. The violation of the null energy condition is
allowed. Hence, such component can also represent a phantom fluid. The model is
tested using supernova type Ia and matter power spectrum data. The supernova
test leads to preferred values for configurations representing the phantom
fluid. The matter power spectrum constraints for the dark energy equation of
state parameter are highly degenerated. In both cases, values for the equation
of state parameter corresponding to the phantom fluid are highly admitted if no
particular prior is used.Comment: Latex file, 12 pages, 12 figures in eps forma
Interoperability and Standards: The Way for Innovative Design in Networked Working Environments
Organised by: Cranfield UniversityIn today’s networked economy, strategic business partnerships and outsourcing has become the dominant
paradigm where companies focus on core competencies and skills, as creative design, manufacturing, or
selling. However, achieving seamless interoperability is an ongoing challenge these networks are facing,
due to their distributed and heterogeneous nature. Part of the solution relies on adoption of standards for
design and product data representation, but for sectors predominantly characterized by SMEs, such as the
furniture sector, implementations need to be tailored to reduce costs. This paper recommends a set of best
practices for the fast adoption of the ISO funStep standard modules and presents a framework that enables
the usage of visualization data as a way to reduce costs in manufacturing and electronic catalogue design.Mori Seiki – The Machine Tool Compan
Photon mass as a probe to extra dimensions
In this manuscript we show that the geometrical localization mechanism
implies a four dimensional mass for the photon. The consistence of the model
provides a mass given exactly by where is the Ricci
scalar. As a consequence, the cosmological photon has a mass related to the
vacuum solution of the Einstein equation. At the present age of the universe we
have a dS vacuum with , where Lambda is a positive cosmological
constant. With this we find that kg, which
is below the present experimental upper bounds, and such correction may be
observed in the next years with more precise measurements. By considering the
value of inside some astrophysical sources and environments we find that
the bound is also satisfied. The experimental verification of this mass, beyond
pointing to the existence of extra dimensions, would imply in a fundamental
change in cosmology, astrophysics and in particle physics since the same
mechanism is valid for non-abelian gauge fields.Comment: 4 page
Does Geometric Coupling Generates Resonances?
Geometrical coupling in a co-dimensional one Randall-Sundrum scenario (RS) is
used to study resonances of form fields. The resonances are calculated
using the transfer matrix method. The model studied consider the standard RS
with delta-like branes, and branes generated by kinks and domain-wall as well.
The parameters are changed to control the thickness of the smooth brane. With
this a very interesting pattern is found for the resonances. The geometrical
coupling does not generate resonances for the reduced form in all cases
considered.Comment: 10 pages, 10 figure
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