Related papers: Force Behaviour in Radiation-Dominated Friedmann U…
We take an axisymmetric rotating universe model by crossing with a time dependent factor and evaluate its force and momentum in this evolving universe. It is concluded that it behaves exactly like a Friedmann model. We also extend this…
Two models are given by crossing the Friedmann metrics with Schwarzschild and Kerr metrics. In these evolving universes with a gravitational source, the force four-vector and the corresponding potentials are evaluated.
The classical and quantum models of the Friedmann universe originally filled with a scalar field and radiation have been studied. The radiation has been used to specify a reference frame that makes it possible to remove ambiguities in…
We consider a Friedmann model of the universe with bulk viscous matter and radiation as the cosmic components. We study the asymptotic properties in the equivalent phase space by considering the three cases for the bulk viscous coefficient…
According to observations, in our Universe for gravitational phenomena in a Newtonian approximation the Newtonian non-modified relations are valid. The Friedmann equations of universe dynamics describe infinite number of relativistic…
A highly excited Friedmann universe filled with a scalar field and radiation has been considered. On the basis of a direct solution to the quantum-mechanical problem with a well-defined time variable, it has been shown that such a universe…
The effect of force-depending radiation reaction on charge motion traveling inside an undulator is studied using the new force approach for radiation reaction. The effect on the dynamics of a charged particle is determined with the hope…
The Friedman universe is re-examined in a context that is non-standard only in that the properties of matter are postulated in the form of an action principle. Applications to equilibrium configurations of ideal stars have already been…
A new approach has been used to evaluate the momentum and angular momentum of the isotropic and homogeneous cosmological models. It is shown that the results obtained for momentum exactly coincide with those already available in the…
A four-vector field in flat space-time, satisfying a gauge-invariant set of second-order differential equations, is considered as a unified field. The model variational principle corresponds to the general covariance idea and gives rise to…
The paper deals with a spatially homogeneous and isotropic FRW space-time filled with perfect fluid and dark energy components. The two sources are assumed to interact minimally, and therefore their energy momentum tensors are conserved…
In this paper, we point out that the 4-vector force acting on a particle is always in the direction orthogonal to the 4-vector velocity of the particle in the 4-dimensional space-time, rather than along the line joining the particle and the…
Recently some authors concluded that the energy and momentum of the Fiedman universes, flat and closed, are equal to zero locally and globally (flat universes) or only globally (closed universes). The similar conclusion was also done for…
We propose that the Universe is filled with a massive vector field, non-minimally coupled to gravitation. The field equations of the model are consistently derived and their application to cosmology is considered. The Friedmann equations…
According to the observations, in our expansive and isotropic relativistic Universe for the gravitational phenomena in a Newtonian approximation the Newtonian non-modified relations are valid. The Friedmann general equations of isotropic…
Active motion is a concept in complex systems theory and was successfully applied to various problems in nonlinear dynamics. Explicit studies for gravitational potentials were missing so far. We interpret the Friedmann equations with…
In this work the homogeneous and isotropic Universe of Friedmann-Robertson-Walker is studied in the presence of two fluids: stiff matter and radiation described by the Schutz's formalism. We obtain to the classic case the behaviour of the…
The causal interpretation of quantum mechanics is applied to a homogeneous and isotropic quantum universe, whose matter content is composed by non interacting dust and radiation. For wave functions which are eigenstates of the total dust…
The purpose of this paper is to investigate the oscillatory behavior of the universe through a Schr\"odinger-like Friedmann equation and a modified gravitational background described by the theory of f (R) gravity. The motivation for this…
In this letter, we show that in a particular braneworld scenario with variable brane tension, we obtain matter acting as dark energy while the gravitational constant $G$ promoted to a scalar field on the brane plays the role of matter (both…