58 research outputs found
Stability of de Sitter Solutions in Non-local Cosmological Models
A non-local gravity model, which includes a function , where
is the d'Alembert operator, is considered. For the model with an
exponential de Sitter solutions are explored, without any
restrictions on the parameters. Using Hubble-normalized variables, the
stability of the de Sitter solutions is investigated, with respect to
perturbations in the Bianchi I metric, in the case of zero cosmological
constant, and sufficient conditions for stability are obtained.Comment: 10 pages, has been published in the proceedings of the XXth
International Workshop on High Energy Physics and Quantum Field Theory
(QFTHEP'2011), http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=13
Interdependence between integrable cosmological models with minimal and non-minimal coupling
We consider the relation between exact solutions of cosmological models
having minimally and non-minimally coupled scalar fields. This is done for a
particular class of solvable models which, in the Einstein frame, have
potentials depending on hyperbolic functions and in the Jordan frame, where the
non-minimal coupling is conformal, possess a relatively simple dynamics. We
show that a particular model in this class can be generalized to the cases of
closed and open Friedmann universes and still exhibits a simple dynamics.
Further we illustrate the conditions for the existences of bounces in some
sub-classes of the set of integrable models we have considered.Comment: 15 pages, v2: figures and references added, accepted for publication
in CQ
Some Problems of Criminal Liability for Illegal Extraction of Biological Water Resources
In this article the attention is focused on the problems arising from qualification of signs of the objective party of a crime structure (Art. 256 of the Сriminal Code of the Russian Federation); the ways of further improvement of this criminal rule of law are offered as well
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