Related papers: Constraints on $\Lambda(t)$-cosmology with power l…
In order to test the possible interaction between dark energy and dark matter, we investigate observational constraints on a phenomenological scenario, in which the ratio between the dark energy and matter densities is proportional to the…
In this work, we consider the cosmological constraints on the interacting dark energy models. We generalize the models considered previously by Guo {\it et al.}, Costa and Alcaniz, and try to discuss two general types of models: type I…
While $\Lambda$CDM provides a good fit to cosmological data, it fails to address many of the outstanding questions in contemporary cosmology. Chief among these are the Hubble tension and the apparent dynamical nature of dark energy as…
To find more deliberate f(R,T) cosmological solutions, we proceed our previous paper further by studying some new aspects of the considered models via investigation of some new cosmological parameters/quantities to attain the most…
It is generally assumed that the two dark components of the energy density of the universe, a smooth component called dark energy and a fluid of nonrelativistic weakly interacting particles called dark matter, are independent of each other…
Models with dark energy decaying into dark matter have been proposed to solve the coincidence problem in cosmology. We study the effect of such coupling in the matter power spectrum. Due to the interaction, the growth of matter density…
We derive new limits on the value of the cosmological constant, $\Lambda$, based on the Einstein bending of light by systems where the lens is a distant galaxy or a cluster of galaxies. We use an amended lens equation in which the…
The consideration of dark energy's quanta, required also by thermodynamics, introduces its chemical potential into the cosmological equations. Isolating its main contribution, we obtain solutions with dark energy decaying to matter or…
Dark energy models which alter the relative scaling behavior of dark energy and matter could provide a natural solution to the cosmic coincidence problem - why the densities of dark energy and dark matter are comparable today. A generalized…
We study cosmological perturbations in a model of unified dark matter and dark energy with a sharp transition in the late-time universe. The dark sector is described by a dark fluid which evolves from an early stage at redshifts $z > z_C$…
One of the important issues both in particle physics and cosmology relates to whether dark energy is a cosmological constant $\Lambda$, or is dynamical in nature such as quintessence. In this work, we discuss a model of quintessence…
A simple speed-up cosmology model is proposed to account for the dark energy puzzle. We condense contributions from dark energy and curvature term into one effective parameter in order to reduce parameter degeneracies and to find any…
The critical issue in cosmology today lies in determining if the cosmological constant is the underlying ingredient of dark energy. Our profound lack of understanding of the physics of dark energy places severe constrains on our ability to…
We investigate an extended cosmological model motivated by the asymptotic safety of gravitational field theory, in which the matter and radiation densities and the cosmological constant receive a correction parametrized by the parameters…
A cosmological model of dark energy interacting with dark matter and another general component of the universe is considered. The evolution equations for coincidence parameters r and s, which represent the ratios between the dark energy and…
We discuss models for the cosmological dark sector in which the energy density of a scalar field approximates Einstein's cosmological constant and the scalar field value determines the dark matter particle mass by a Yukawa coupling. A model…
We propose a general class of interacting models in which the interaction between the CDM component and $\Lambda$ is parameterized by an arbitrary function of the cosmic scale factor $\epsilon(a)$. Differently from other dynamical $\Lambda$…
Astronomical observations suggest that the current standard $\Lambda$-Cold Dark Matter model in modern cosmology has some discrepancies when fitting the data during the whole expansion history of the universe. To solve the Hubble constant…
To explore whether there is new physics going beyond the standard cosmological model or not, we constrain seven cosmological models by combining the latest and largest Pantheon Type Ia supernovae sample with the data combination of baryonic…
We have studied the closed universe model with the variable cosmological term, which is presented as a sum of two terms: Lambda=Lambda_0 -k R. First term Lambda_0 is a constant and it is describing a sum of quantum field's zero…