Related papers: Dark-Energy Dynamics Required to Solve the Cosmic …
We here investigate the model of interacting dark energy in the context of five dimensional brane cosmology. The effective equations of state of dark energy are evaluated for various choices of the variable time dependent cosmological…
Cosmological analysis based on currently available observations are unable to rule out a sizeable coupling between dark energy and dark matter. However, the signature of the coupling is not easy to grasp, since the coupling is degenerate…
We propose a new model of Early Dark Energy (EDE) as a solution to the Hubble tension in cosmology, the apparent discrepancy between local measurements of the Hubble constant $H_0\simeq 74$ km s$^{-1}$ Mpc$^{-1}$ and $H_0\simeq 67$ km…
Since the discovery of the accelerated expansion of the Universe, the constraints on the equation of state $w_\text{DE}$ of dark energy, the stress-energy component responsible for the acceleration, have tightened significantly. These…
In order to test if there is energy transfer between dark energy and dark matter, we investigate cosmological constraints on two forms of nontrivial interaction between the dark matter sector and the sector responsible for the acceleration…
We discuss a model of non perturbative decay of dark energy into hot and cold dark matter. This model provides a mechanism from the field theory to realize the energy transfer from dark energy into dark matter, which is the requirement to…
A model of cosmology, that arises from the hypothesis that ordinary matter, dark matter and dark energy are made of the same stuff, is studied. It is argued that this hypothesis is a consequence of considering space and time in the same…
Although the cosmic concordance cosmology is quite successful in fitting data, fine tuning and coincidence problems apparently weaken it. We review several possibilities to ease its problems, by considering various kinds of dynamical Dark…
We investigate a class of interacting dark energy and dark matter (DM) models, where dark energy is modeled as a $k$-essence scalar field with an inverse-square potential. Two general forms of interaction are considered: one proportional to…
In this paper, we study several models and parameterizations of dynamical dark energy (DE) that have been studied already in the past, in conjunction with the recently proposed model $w$XCDM, the running vacuum model (RVM) with and without…
We propose the Locally Pumped Dark Energy (LPDE) mechanism in which cosmic acceleration is triggered by the emergence of non-linear dark matter structure. In an effective-field-theory description, coarse-graining over the density contrast…
We investigate Dark Energy by associating it with vacuum energy or Cosmological constant ${\Lambda}$ which is taken to be dynamic in nature. Our approach is phenomenological and falls within the domain of variable-$\Lambda$ Cosmology.…
We study perturbation of holographic dark energy and find it be stable. We study the fate of the universe when interacting holographic dark energy is present, and discuss a simple phenomenological classification of the interacting…
The matching of our epoch of existence with the approximate equality of dark energy and dark matter energy densities is an apparent further fine-tuning, beyond the already troubling 120 orders of magnitude that separate dark energy from the…
In this manuscript, we investigate late-time cosmology and the evolution of cosmic structures using an interacting dark fluid model in which dark matter (DM) and dark energy (DE) interact through a diffusive mechanism. To provide a…
Dark Energy not only has background effects through its equation of state $w_{DE}$, but also it can cluster through its sound speed $c^2_{sDE}$, subject to certain conditions. As is well-known, for dynamical dark energy models, dark energy…
Early dark energy (EDE) that becomes subdominant around the epoch of matter-radiation equality can be used to ease the Hubble tension. However, there is a theoretical problem that why the energy scale of EDE is in coincidence with that of…
We propose a cosmological model that makes a significant step toward solving the coincidence problem of the near similarity at the present of the dark energy and dark matter components. Our cosmology has the following properties: a) among…
The nature of dark energy (DE) remains elusive, even though it constitutes the dominant energy-density component of the Universe and drives the late-time acceleration of cosmic expansion. By combining measurements of the expansion history…
The observed cosmic acceleration was attributed to an exotic dark energy in the framework of classical general relativity. The dark energy behaves very similar with vacuum energy in quantum mechanics. However, once the quantum effects are…