Related papers: Unified Dark Matter models with fast transition
The dark energy-cold dark matter paradigm ($\Lambda$CDM) has gained widespread acceptance because it explains the pattern of anisotropies observed in the cosmic microwave background radiation, the observed distribution of large scale…
If dark energy interacts with dark matter, this gives a new approach to the coincidence problem. But interacting dark energy models can suffer from pathologies. We consider the case where the dark energy is modelled as a fluid with constant…
(Abridged) Despite the success of Cold Dark Matter (CDM) in explaining a wide range of observations, the microscopic nature of dark matter is still unknown. Attempts to detect WIMPs, the most commonly studied form, have not yet succeeded.…
We investigate the cosmological implications of a generalized total equation of state (EoS) model by constraining its parameters using observational datasets to effectively characterize the universe's expansion history and its dynamic…
While cold dark matter is widely supported by a range of cosmological observations, it encounters several difficulties at smaller scales. These issues have prompted the investigation of various alternative dark matter candidates, leaving…
We present an interacting model with a phenomenological interaction, $\bar{Q}$, between a cold dark matter (DM) fluid and a dark energy (DE) fluid, which takes a time-varying equation of state (EoS) parameter, $\mathrm{\omega_{DE}}$. Here,…
We study a class of Unified Dark Matter (UDM) models based on generalized K-essence, where a single scalar field with non-canonical kinetic terms accounts for dark radiation, dark matter, and dark energy. Starting from the purely kinetic…
In this study, we explore the impact of various combinations of CMB-independent datasets, including the recent DESI BAO measurements, on the equation of state (EoS) of dark energy and other cosmological parameters within the framework of…
Exotic dark matter (EDM) refers to a dark matter species whose equation of state deviates from zero at late times. This behavior enables it to model a variety of non-standard late-time cosmologies, offering alternatives to various dark…
In the so-called unified dark fluid models, the dark sector gets simplified because dark matter and dark energy are replaced by a single fluid that behaves as the former at early times and as the latter at late times. In this short paper we…
Cosmic acceleration is widely believed to require either a source of negative pressure (i.e., dark energy), or a modification of gravity, which necessarily implies new degrees of freedom beyond those of Einstein gravity. In this paper we…
Motivated by the observed cosmic matter distribution, we present the following conjecture: due to the formation of voids and opaque structures, the average matter density on the path of the light from the well-observed objects changes from…
A puzzling implication of current data interpreted in the $\Lambda$CDM cosmology is the preference for a negative sum of neutrino masses. Moving to $w_0w_a$CDM brings an appreciable fraction of the neutrino mass posterior back to positive…
In this latter author would like to consider interaction between a dark energy based on Generalized Uncertainty Principle (GUP) and a Dark Matter described by effective EoS: $P =…
The Dark Sector is described by an additional barotropic fluid which evolves adiabatically during the universe's history and whose adiabatic exponent $\gamma$ is derived from the standard definitions of specific heats. Although in general…
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…
A new phenomenological dark energy model, originally associated to the large-scale structure formation and considered as a solution to the fine-tuning and coincidence problems related to the cosmological constant, was analyzed within the…
The dark energy in the Universe is described in the context of modified Friedmann equations as a fluid parameterized by the density of dark matter and undergoing an adiabatic expansion. This formulation is applied to the Cardassian model.…
We test the viability of a single fluid cosmological model containing a transition from a dark-matter-like regime to a dark-energy-like regime. The fluid is a k-essence scalar field with a well-defined Lagrangian. We constrain its model…
In this paper, we investigate an extension of the standard $\Lambda$CDM model by allowing: a temporal evolution in the equation of state (EoS) of DM via Chevallier-Polarski-Linder parametrization, and the constant non-null sound speed. We…