Related papers: Dynamical Mutation of Dark Energy
In this dissertation, the nature of Dark Energy (DE) is examined from both theoretical and phenomenological perspectives. The possibility of DE being a dynamic quantity in quantum field theory (QFT) in curved spacetime is studied. The…
The problem of dark energy is briefly reviewed in both theoretical and observational aspects. In the theoretical aspect, dark energy scenarios are classified into symmetry, anthropic principle, tuning mechanism, modified gravity, quantum…
We explore the possibility that the dark energy is due to a potential of a scalar field and that the magnitude and the slope of this potential in our part of the universe are largely determined by anthropic selection effects. We find that,…
We study a class of early dark energy models which has substantial amount of dark energy in the early epoch of the universe. We examine the impact of the early dark energy fluctuations on the growth of structure and the CMB power spectrum…
In this Letter we point out to the possibility that the cloud of the vacuum energy excitations in gravitation fields surrounding galaxies forms a component of dark matter. These clouds of the vacuum energy excitations interact…
For a general dark-energy equation of state, we estimate the maximum possible radius of massive structures that are not destabilized by the acceleration of the cosmological expansion. A comparison with known stable structures constrains the…
Measurement of accelerated expansion in the Universe led to propose a new cosmic fluid as its cause: dark energy. Its various incarnations offer a wealth of models whose relevance it is important to discriminate via contacts with…
It is suggested that the vacuum expectation of the quantum vacuum energy-momentum is zero, but quantum fluctuations give rise to a space-time curvature equivalent to that of a cosmological constant or dark energy. Calculations within…
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…
A formula to calculate the quantum fluctuations of energy in small subsystems of a hot and relativistic gas is derived. We find an increase in fluctuations for subsystems of small sizes, but we agrees with the energy fluctuations in the…
The fact that the energy densities of dark energy and matter are similar currently, known as the coincidence problem, is one of the main unsolved problems of cosmology. We present here a model in which a spatial curvature of the universe…
Expressions for the quantum fluctuations of energy density have been derived for the subsystems consisting of hot relativistic gas of particles with spin-$\frac{1}{2}$ and mass $m$. Our expressions for the fluctuation depend on the form of…
Dark energy might have an influence on the formation of non--linear structures during the cosmic history. For example, in models in which dark energy couples to dark matter, it will be non--homogeneous and will influence the collapse of a…
The present status of our knowledge about the dark matter and dark energy is reviewed. Bounds on the content of cold and hot dark matter from cosmological observations are discussed in some detail. I also review current bounds on the…
Observations provide increasingly strong evidence that the universe is accelerating. This revolutionary advance in cosmological observations confronts theoretical cosmology with a tremendous challenge, which it has so far failed to meet.…
In this paper, by analyzing the dynamics of the inhomogeneous quintessence dark energy, we find that the gradient energy of dark energy will oscillate and gradually vanish, which indicates the gradient energy of the scalar field present in…
In this work we perform some studies related to dark energy. Firstly, we propose a dynamical approach to explain the dark energy content of the universe. We assume that a massless scalar field couples to the Hubble parameter with some…
By studying the present cosmological data, particularly on CMB, SNeIA and LSS, we find that the future fate of the universe, for simple linear models of the dark energy equation-of-state, can vary between the extremes of (I) a divergence of…
The quasi-static solutions of the matter density perturbation in various dark energy models and modified gravity models have been investigated in numerous papers. However, the oscillating solutions in those models have not been investigated…
Relations similar to work and exchange fluctuations have been recently derived for open systems dynamically evolving in the presence of an ancilla. Extending these relations and constructing a non-equilibrium Helmholtz equation we derive a…