Related papers: Cosmic backreaction and Gauss's law
Backreaction in the cosmological context is a longstanding problem that is especially important in the present era of precise cosmology. The standard model of a homogeneous background plus density perturbations is most probably…
The observation that accelerated cosmic expansion appears to start around the time that nonlinear cosmic structure is appearing seems like an extraordinary coincidence, unless the acceleration is somehow driven by the emergence of the…
This is the third paper in a series of four in which we use space adiabatic methods in order to incorporate backreactions among the homogeneous and between the homogeneous and inhomogeneous degrees of freedom in quantum cosmological…
The backreaction of structure formation influences the cosmological evolution equation for the homogenous and isotropic average metric. In a cold dark matter universe this effect leads only to small corrections unless a substantial fraction…
We calculate the back reaction of cosmological perturbations on a general relativistic variable which measures the local expansion rate of the Universe. Specifically, we consider a cosmological model in which matter is described by a single…
Cosmic backreaction as an additional source of the expansion of the universe has been a debate topic since the discovery of cosmic acceleration. The major concern is whether the self interaction of small-scale nonlinear structures would…
In relativistic cosmology, the formation of nonlinear inhomogeneities can induce non-negligible backreaction on late-time expansion. Among the important consequences for precision cosmology is the potential impact on the linear growth of…
We develop a new formalism for the treatment of gravitational backreaction in the cosmological setting. The approach is inspired by projective techniques in non-equilibrium statistical mechanics. We employ group-averaging with respect to…
Cosmology is built on a relativistic understanding of gravity, where the geometry of the Universe is dynamically determined by matter and energy. In the cosmological concordance model, gravity is described by General Relativity, and it is…
Modelling structure formation across the full dynamical range of the Universe remains a major challenge in cosmology. This difficulty originates from a fundamental limitation of geodesics in general relativity: a one-parameter family of…
The paper discusses back reaction effects in cosmology, (\'{a} la Buchert et. al.), induced by noncommutative geometry effects in fluid. We have used generalizations of an action formulation of noncommutative fluid model, proposed earlier…
We investigate the effect of backreaction due to inhomogeneities on the evolution of the present universe within the Buchert framework. Our analysis shows how backreaction from inhomogeneities in the presence of the cosmic event horizon…
Astronomical observations reveal hierarchical structures in the Universe, from galaxies, groups of galaxies, clusters and superclusters, to filaments and voids. On the largest scales it seems that some kind of statistical homogeneity can be…
For the study of cosmological backreacktion an avaragng procedure is required. In this work a covariant and gauge invariant averaging formalism for finite volumes will be developed. This averaging will be applied to the scalar parts of…
Possible analogies between vacuum state and quantum fluid provide a model to study vacuum energy density induced by thermal corrections, space-time curvature, boundary conditions and quantum back-reaction. We find that vacuum energy density…
It has been suggested that the accelerated expansion of the Universe is due to backreaction of small scale density perturbations on the large scale spacetime geometry. While evidence against this suggestion has accumulated, it has not yet…
The non-linearity of Einstein's equations makes it possible for small-scale matter inhomogeneities to affect the Universe at cosmological distances. We study the size of such effects using a simple heuristic model that captures the most…
In an inhomogeneous universe, an observer associated with a particular matter field does not necessarily measure the same cosmological evolution as an observer in a homogeneous and isotropic universe. Here we consider, in the context of a…
Numerical N-body simulations of large scale structure formation in the universe are based on Newtonian gravity. However, according to our current understanding, the most correct theory of gravity is general relativity. It is therefore…
Back-reaction of the massless scalar field vacuum to the Universe expansion is considered. Automatic renormalization procedure based on the equations of motion instead of the Friedman equation is used to avoid the cosmological constant…