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F. Felegary

Publications and source records attributed to F. Felegary.

9 recordsLinked to original sources
arXiv2017

Interacting Holographic Dark Energy model in Brans-Dicke cosmology and coincidence problem

We study the dynamics of interacting holographic dark energy model in Brans-Dicke cosmology for the future event horizon and the Hubble horizon cut-offs. We determine the system of first-order differential equations for the future event horizon and Hubble horizon cut-offs, and obtain the corresponding fixed points, attractors, repellers and saddle points. Finally, we investigate the cosmic coincidence problem in this model for the future event horizon and Hubble horizon cut-offs and find that for both cut-offs and for a variety of Brans-Dicke parameters the coincidence problem is almost resolved.

gr-qc↗
arXiv2017

Evolution of spherical overdensities in new agegraphic dark energy model

We study the structure formation by investigating the spherical collapse model in the context of new agegraphic dark energy model in flat FRW cosmology. We compute the perturbational quantities $g(a)$, $δ_{c}(z_{c})$, $λ(z_{c})$, $ξ(z_{c})$, $Δ_{vir}(z_{c})$, $\log[νf(ν)]$ and $\log[n(k)]$ for the new agegraphic dark energy model and compare the results with those of EdS and $ΛCDM$ models. We find that there is a dark energy dominated universe at low redshifts and a matter dominated universe at high redshifts in agreement with observations. Also, the size of structures, the overdense spherical region, and the halo size in the new agegraphic dark energy model are found smaller, denser, and larger than those of EdS and $ΛCDM$ models. We compare our results with the results of tachyon scalar field and holographic dark energy models.

gr-qc↗
arXiv2017

Evolution of spherical over-densities in tachyon scalar field model

We study the tachyon scalar field model in flat FRW cosmology with the particular potential $ϕ^{-2}$ and the scale factor behavior $a(t)=t^n$. We consider the spherical collapse model and investigate the effects of the tachyon scalar field on the structure formation in flat FRW universe. We calculate $δ_{c}(z_{c})$, $λ(z_{c})$, $ξ(z_{c})$, $Δ_{V}(z_{c})$, $\log [νf(ν)]$ and $\log [n(k)]$ for the tachyon scalar field model and compare the results with the results of EdS model and $ΛCDM$ model. It is shown that in the tachyon scalar field model the structure formation may occur earlier, in comparison to the other models.

gr-qc↗
arXiv2017

Holographic dark energy models with Interactions and entropy corrections for different cutoffs in the Brans-Dicke cosmology

In the framework of Brans-Dicke cosmology, we have studied the interacting power-law and logarithmic entropy-corrected holographic dark energy models with different cut-offs. The Brans-Dicke parameter is investigated versus the conditions for the acceleration and phantom phases to show that which entropy corrected model can exhibit acceleration with or without the phantom phase at early and present time universes. Moreover, the classical stability or instability of the interacting power-law and logarithmic entropy-corrected holographic dark energy models with different cut-offs is determined at early and present time

gr-qc↗
arXiv2016

Inflation via logarithmic entropy-corrected holographic dark energy model

We study the inflation via logarithmic entropy-corrected holographic dark energy LECHDE model with future event horizon, particle horizon and Hubble horizon cut-offs, and compare the results with those of obtained in the study of inflation by holographic dark energy HDE model. In comparison, the spectrum of primordial scalar power spectrum in the LECHDE model becomes redder than the spectrum in HDE model. Moreover, the consistency with the observational data in LECHDE model of inflation, constrains the reheating temperature and Hubble parameter by one parameter of holographic dark energy and two new parameters of logarithmic corrections.

gr-qc↗
arXiv2011

Interacting viscous entropy-corrected holographic scalar field models of dark energy with time-varying G in modified FRW cosmology

We study the entropy-corrected version of the holographic dark energy (HDE) model in the framework of modified FRW cosmology. We consider a non-flat universe filled with an interacting viscous entropy-corrected HDE (ECHDE) with dark matter. We also include the case of variable gravitational constant G in our model. We obtain the equation of state and the deceleration parameters of the interacting viscous ECHDE. Moreover, we reconstruct the potential and the dynamics of the quintessence, tachyon, K-essence and dilaton scalar field models according to the evolutionary behavior of the interacting viscous ECHDE model with time-varying G.

gr-qc↗
arXiv2011

Thermodynamical description of interacting entropy-corrected new agegraphic dark energy

To explain the accelerating universe driven by dark energy, a so-called "entropy-corrected new agegraphic dark energy" (ECNADE), was recently proposed with the help of quantum corrections to the entropy-area relation in the framework of loop quantum cosmology. Using this definition, we study its thermodynamical features including entropy and energy conservation. We discuss the thermodynamical interpretation of the interaction between ECNADE and dark matter in a non-flat universe bounded by the apparent horizon. We obtain a relation between the interaction term of the dark components and thermal fluctuation.

gr-qc↗