ﻻ يوجد ملخص باللغة العربية
The properties of dynamical Dark Energy (DE) and, in particular, the possibility that it can form or contribute to stable inhomogeneities, have been widely debated in recent literature, also in association to a possible coupling between DE and Dark Matter (DM). In order to clarify this issue, in this paper we present a general framework for the study of the nonlinear phases of structure formation, showing the equivalence between two possible descriptions of DE: a scalar field phi self-interacting through a potential V(phi) and a perfect fluid with an assigned negative equation of state w(a). This enables us to show that, in the presence of coupling, the mass of DE quanta may increase where large DM condensations are present, so that also DE may partake to the clustering process.
We consider cosmological dynamics of nonminimally coupled scalar field in the scalar-torsion gravity in the presence of a hydrodynamical matter. Potential of the scalar field have been chosen as power-law with negative index, this type of potentials
The fluid/gravity correspondence establishes how gravitational dynamics, as dictated by Einsteins field equations, are related to the fluid dynamics, governed by the relativistic Navier-Stokes equations. In this work the correspondence is extended, w
We obtain a two-parameter set of solutions, which represents a spherically symmetric space-time with a superposition of a neutral fluid and an electric field. The electromagnetic four-potential of this Einstein-Maxwell space-time is taken in the form
We investigate the second-order gravitational scalar perturbations for a barotropic fluid. We derive the effective energy-momentum tensor described by the quadratic terms of the gravitational and the matter perturbations. We show that the second-orde
We consider a minimally coupled scalar field with a monomial potential and a perfect fluid in flat FLRW cosmology. We apply local and global dynamical systems techniques to a new three-dimensional dynamical systems reformulation of the field equation