Related papers: Dark energy from backreaction
We review the effect of the formation of nonlinear structures on the expansion rate, spatial curvature and light propagation in the universe, focusing on the possibility that it could explain cosmological observations without the…
The accelerated expansion of the universe is ascribed to the existence of dark energy. Black holes accretion of dark energy induces a mass change proportional to the energy density and pressure of the background dark energy fluid. The time…
In this letter, it is obtained using dual role of the Ricci scalar (physical as well as geometrical role of the Ricci scalar curvature) in a natural way without any input in the theory for it. In contrast to other models, where an idea for…
We show that dark energy and dark matter can be described simultaneously by ordinary Einstein gravity interacting with a single scalar field provided the scalar field Lagrangian couples in a symmetric fashion to two different spacetime…
In the present work we have searched the existence of the late time acceleration of the Universe. The matter source that is responsible for the late time acceleration of the Universe consists of cosmic fluid with the equation of state…
The modified F(R)-scalar-Gauss-Bonnet gravity is proposed as dark energy model. The reconstruction program for such theory is developed. It is explicitly demonstrated that the known classical universe expansion history (deceleration epoch,…
We analytically and numerically show that the acceleration of the cosmic expansion could be explained by a Quadratic Gravity model which is known to be able to trigger sufficient inflation, with neither negative pressure matter nor…
We have observed the acceleration of the expansion of the universe. To explain this phenomenon, we usually introduce the dark energy (DE) which has a negative pressure or we need to modify the Einstein's equation to produce a term which is…
We present a brief review of various approaches to late time acceleration of universe. The cosmological relevance of scaling solutions is emphasized in case of scalar field models of dark energy. The underlying features of a variety of…
We introduce the concept of back-reaction in relativistic cosmological modeling. Roughly speaking, this can be thought of as the difference between the large-scale behaviour of an inhomogeneous cosmological solution of Einstein's equations,…
In this paper, by analyzing the dynamics of the inhomogeneous quintessence dark energy, we find that the gradient energy of dark energy will oscillate and gradually vanish, which indicates the gradient energy of the scalar field present in…
Recent observations from the Dark Energy Spectroscopic Instrument (DESI 2025) indicate a weakening of cosmic acceleration at low redshifts $z < 1$, with effective dark energy equation of state parameters $w_0 > -1$ and $w_a < 0$. We…
In inhomogeneous cosmology, restricting attention to an irrotational dust matter model, backreaction arises in terms of the deviation of the averaged spatial scalar curvature from a constant-curvature model on some averaging domain $D$,…
Constantly accumulating observational data continue to confirm that about 70% of the energy density today consists of dark energy responsible for the accelerated expansion of the Universe. We present recent observational bounds on dark…
It has been suggested that the acceleration of the Universe may be due to the backreaction of perturbations to the Friedmann-Robertson-Walker background. For a Universe dominated by cold dark matter, it is known that the backreaction of…
We discuss briefly discrete space effects and show that this leads to space reflection asymmetry and also a minor modification of Einstein's energy-mass formula.
It is suggested that the apparently disparate cosmological phenomena attributed to so-called 'dark matter' and 'dark energy' arise from the same fundamental physical process: the emergence, from the quantum level, of spacetime itself. This…
In this paper we review in detail a number of approaches that have been adopted to try and explain the remarkable observation of our accelerating Universe. In particular we discuss the arguments for and recent progress made towards…
Regionally averaged relativistic cosmologies have recently been considered as a possible explanation for the apparent late time acceleration of the Universe. This contribution reports on a mean field description of the backreaction in terms…
We study backreaction in dust universes using exact equations which do not rely on perturbation theory, concentrating on theoretical and observational constraints. In particular, we discuss the recent suggestion (in hep-th/0503117) that…