Related papers: Is it possible to separate baryonic from dark matt…
Galaxies and their dark-matter halos have posed several challenges to the Dark Energy plus Cold Dark Matter (LCDM) cosmological model. These discrepancies between observations and theory intensify for the lowest-mass (`dwarf') galaxies.…
The standard $\Lambda$CDM model of cosmology is formulated as a simple modified gravity coupled to a single scalar field ("darkon") possessing a non-trivial hidden nonlinear Noether symmetry. The main ingredient in the construction is the…
We demonstrate how much it is possible to deviate from the standard cosmological paradigm of inflation-assisted LambdaCDM, keeping within current observational constraints, and without adding to or modifying any theoretical assumptions. We…
We consider cosmologies in which a dark-energy scalar field interacts with cold dark matter. The growth of perturbations is followed beyond the linear level by means of the time-renormalization-group method, which is extended to describe a…
In this paper, we introduce a scale-independent energy-momentum squared gravity (EMSG) that allows different gravitational couplings for different types of sources, which may lead to scenarios with many interesting applications/implications…
We perform a detailed comparison between the Logotropic model [P.H. Chavanis, Eur. Phys. J. Plus 130 (2015) 130] and the $\Lambda$CDM model. These two models behave similarly at large (cosmological) scales up to the present. Differences…
The increasingly significant tensions within $\Lambda$CDM, combined with the lack of detection of dark matter (DM) in laboratory experiments, have boosted interest in non-minimal dark sectors, which are theoretically well-motivated and…
Recently, a novel dictionary relating solutions of the Einstein--Scalar--Maxwell theory to solutions of gauged Skyrme--Maxwell--Einstein models in $(3+1)$ dimensions has been established. This development provides a clear and systematic…
We consider new models of dark energy with finite time future singularities, by introducing the pressure density as a function of the scale factor. This approach gives acceptable phenomenological models of dark energy, practically…
We study a model of scalar field with a general non-minimal kinetic coupling to itself and to the curvature. The cosmological dynamics of this model and the issue of accelerated expansion is analyzed. Solutions giving rise to power law…
We propose a revised cosmological scenario that extends the $\Lambda$ Cold Dark Matter ($\Lambda$CDM) framework by incorporating metric $f(R)$ gravity in the Jordan frame. In this model, the dark energy component arises from a non-minimally…
It has been recently shown that tachyonic chameleon model of dark energy in which tachyon scalar field non-minimally coupled to the matter admits stable scaling attractor solution that could give rise to the late-time accelerated expansion…
In the present work we analyze two different models of interaction between dark energy and dark matter, also known as vacuum decay models or $\Lambda(t)$CDM models. In both models, when the $H_0$ parameter is constrained by the Planck…
We explore unification of dark matter and dark energy in a theory containing a scalar field of non-Lagrangian type, obtained by direct insertion of a kinetic term into the energy-momentum tensor. This scalar is different from quintessence,…
An interaction between dark matter and dark energy, proportional to the product of their energy densities, results in a scaling behavior of the ratio of these densities with respect to the scale factor of the Robertson-Walker metric. This…
We revise the cosmological standard model presuming that matter, i.e. baryons and cold dark matter, exhibits a non-vanishing pressure mimicking the cosmological constant effects. In particular, we propose a scalar field Lagrangian $\mathcal…
A component of dark energy has been recently proposed to explain the current acceleration of the Universe. Unless some unknown symmetry in Nature prevents or suppresses it, such a field may interact with the pressureless component of dark…
We propose a new mechanism for explaining the observed asymmetry between matter and antimatter, based on nonperturbative physics at the QCD scale. Our mechanism is a charge separation scenario, making use of domain walls separating the…
An interaction between the vacuum energy and dark matter is an intriguing possibility which may offer a way of solving the cosmological constant problem. Adopting a general prescription for momentum exchange between the two dark components,…
Recent high-resolution simulations that include Cold Dark Matter (CDM) and baryons have shown that baryonic physics can dramatically alter the dark matter structure of galaxies. These results modify our predictions for observed galaxy…