692 research outputs found
An Infinite Number of Closed FLRW Universes for Any Value of the Spatial Curvature
The Friedman-Lemaitre-Robertson-Walker (FLRW) cosmological models are based
on the assumptions of large-scale homogeneity and isotropy of the distribution
of matter and energy. They are usually taken to have spatial sections that are
simply connected; they have finite volume in the positive curvature case, and
infinite volume in the null and negative curvature ones. I want to call the
attention to the existence of an infinite number of models, which are based on
these same metrics, but have compact, finite volume, multiply connected spatial
sections. Some observational implications are briefly mentioned.Comment: 4 pages. Contribution to the 5th International Workshop on Astronomy
and Relativistic Astrophysics (Joao Pessoa, PB, Brazil, October 10-12, 2011)
and to the 1o. Simposio Jayme Tiomno (Brasilia, DF, Brazil, October 27-28,
2011). In version 2: a few minor corrections; two new references added. In
this version: title correction in Ref. 3; dedication paragraph at the en
Preliminary Results on the Empirical Applicability of the Tsallis Distribution in Elastic Hadron Scattering
We show that the proton-proton elastic differential cross section data at dip
position and beyond can be quite well described by a parametrization based on
the Tsallis distribution, with only five free fit parameters. Extrapolation of
the results obtained at 7 TeV to large momentum transfer, suggests that hadrons
may not behave as a black-disk at the asymptotic energy region.Comment: 3 pages, 1 figure, version matching proceedings style, XII Hadron
Physics, 2012, AIP Proc. Con
"Safra zero": resposta ao esqueletamento de cultivares de café em diferentes espaçamentos na linha de plantio.
Some integrals ocurring in a topology change problem
In a paper presented a few years ago, De Lorenci et al. showed, in the
context of canonical quantum cosmology, a model which allowed space topology
changes (Phys. Rev. D 56, 3329 (1997)). The purpose of this present work is to
go a step further in that model, by performing some calculations only estimated
there for several compact manifolds of constant negative curvature, such as the
Weeks and Thurston spaces and the icosahedral hyperbolic space (Best space).Comment: RevTeX article, 4 pages, 1 figur
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