Related papers: Cosmic acceleration from interaction of ordinary f…
We provide a detailed description for power--law scaling Friedmann-Robertson-Walker cosmological scenarios dominated by two interacting perfect fluid components during the expansion. As a consequence of the mutual interaction between the…
We provide a simple mathematical description of the exchange of energy between two fluids in an expanding Friedmann universe with zero spatial curvature. The evolution can be reduced to a single non-linear differential equation which we…
Interactions between dark matter and dark energy with a given equation of state are known to modify the cosmic dynamics. On the other hand, the strength of these interactions is subject to strong observational constraints. Here we discuss a…
The late time accelerated expansion of the universe can be realized using scalar fields with given self-interacting potentials. Here we consider a straightforward approach where a three cosmic fluid mixture is assumed. The fluids are…
We consider scalar perturbations of energy-density for a class of cosmological models where an early phase of accelerated expansion evolves, without any fine-tuning for graceful exit, towards the standard Friedman eras of observed universe.…
ecent observations of type Ia supernovae indicate that the Universe is in an accelerating phase of expansion. The fundamental quest in theoretical cosmology is to identify the origin of this phenomenon. In principle there are two…
We explore the idea that cosmic acceleration may be a byproduct of late-time effects like structure formation in two steps. First, we consider the equation of state for an inhomogeneous cosmic fluid, which may lead to a Gedanken-model for…
The acceleration of ultra high energy cosmic rays is conjectured to occur through various interactions with the electromagnetic fields in different astrophysical objects, like magnetic matter clumps, besides the well-known shock and…
We propose a time-varying cosmological constant with a fixed equation of state, which evolves mainly through its interaction with the background during most of the long history of the universe. However, such interaction does not exist in…
In this paper we have studied the dynamics of accelerating scenario within the framework of scalar field models possessing a non-canonical kinetic term. In this toy model, the scalar field is allowed to interact with the dark matter…
Non-gravitational interaction between two barotropic dark fluids, namely the pressureless dust and the dark energy in a spatially flat Friedmann-Lema\^{i}tre-Robertson-Walker model has been discussed. It is shown that for the interactions…
Accelerated expansion of the Universe may result from an anti-frictional force that is self-consistently exerted on cold dark matter (CDM). Cosmic anti-friction is shown to give rise to an effective negative pressure of the cosmic medium.…
A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by large-scale structure formation, thus eliminating the coincidence and magnitude fine-tuning problems of the Cosmological Constant…
As an explanation for the acceleration of the universe, we propose dark matter with self-interactions characterized by a negative pressure; there is no vacuum energy whatsoever in this Cardassian model. These self-interactions may arise due…
A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by large-scale structure formation, thus eliminating the magnitude and coincidence fine-tuning problems of the Cosmological Constant…
A cosmological model of dark energy interacting with dark matter and another general component of the universe is investigated. We found general constraints on these models imposing an accelerated expansion. The same is also studied in the…
We study in detail the phase space of a Friedmann-Robertson-Walker Universe filled with various cosmological fluids which may or may not interact. We use various expressions for the equation of state, and we analyze the physical…
We explore a cosmological model in which dark matter is non-minimally coupled to gravity at the fluid level. While typically subdominant compared to Standard Model forces, such couplings may dominate dark matter dynamics. We show that this…
It is possible to generate an accelerated period of expansion from reasonable potentials acting between the universe particle constituents. The pressure of primordial nucleons interacting via a simple nuclear potential is obtained via…
In this paper we exploit the theory of the dynamical systems to study the dynamics of the standard cosmological model of the universe, which is known as the $\Lambda$CDM model. We assume that the matter content in our universe consists of…