arXiv subjects

Iuliia Khomenko

Publications and source records attributed to Iuliia Khomenko.

4 recordsLinked to original sources

arXiv2013

A reconstruction of modified holographic Ricci dark energy in $f(R,T)$ gravity

In this paper, we consider a recently proposed model of Dark Energy (DE) know as Modified Holographic Ricci DE (MHRDE) (which is function of the Hubble parameter and its first derivative with respect to the cosmic time $t$) in the light of the $f(R,T)$ model of modified gravity, considering the particular model $f(R,T) = μR + νT$, with $μ$ and $ν$ constants. The equation of state (EoS) parameter $ω_Λ$ approaches but never reaches the value -1, implying a quintessence-like behavior of the model. The deceleration parameter $q$ passes from decelerated to accelerated phase at a redshift of $z\approx 0.2$, showing also a small dependence from the values of the parameters considered. Thanks to the statefinder diagnostic analysis, we observed that the $Λ$CDM phase for the considered model is attainable. We observed that the fractional energy densities for DE and DM $Ω_Λ$ and $Ω_m$ have, respectively, an increasing and a decreasing pattern with the evolution of the universe, indicating an evolution from matter to DE dominated universe. Finally, studying the squared speed of the sound $v_s^2$ for our model, we found that is classically stable.

physics.gen-ph↗

arXiv2013

Statefinder diagnostic of logarithmic entropy corrected holographic dark energy with Granda-Oliveros IR cut-off

In this work, we have studied the logarithmic entropy corrected holographic dark energy (LECHDE) model with Granda-Oliveros (G-O) IR cutoff. The evolution of dark energy (DE) density $Ω'_D$, the deceleration parameter, $q$, and equation of state parameter (EoS), $ω_Λ$, are calculated. We show that the phantom divide may be crossed by choosing proper model parameters, even in absence of any interaction between dark energy and dark matter. By studying the statefinder diagnostic and $ω_Λ-ω_Λ^{\prime}$ analysis, the pair parameters $\{r,s\}$ and $(ω_Λ-ω_Λ^{\prime})$ is calculated for flat GO-LECHDE universe. At present time, the pair $\{r,s\}$ can mimic the $Λ$CDM scenario for a value of $α/β\simeq 0.87$, which is lower than the corresponding one for observational data ($α/β=1.76$) and for Ricci scale ($α/β=2$). We find that at present, by taking the various values of ($α/β$), the different points in $r-s$ and $(ω_Λ-ω_Λ^{\prime})$ plans are given. Moreover, in the limiting case for a flat dark dominated universe at infinity ($t\rightarrow \infty$), we calculate $\{r,s\}$ at G-O scale. For Ricci scale ($α= 2$, $β= 1$) we obtain $\{r=0,s=2/3\}$.

gr-qc↗

arXiv2013

Interacting Ricci Logarithmic Entropy Corrected Holographic Dark Energy in Brans-Dicke Cosmology

In the derivation of Holographic Dark Energy (HDE), the area law of the black hole entropy assumes a crucial role. However, the entropy-area relation can be modified including some quantum effects, motivated from the Loop Quantum Gravity (LQG), string theory and black hole physics. In this paper, we study the cosmological implications of the interacting logarithmic entropy-corrected HDE (LECHDE) model in the framework of Brans-Dicke (BD) cosmology. As system's infrared (IR) cut-off, we choose the average radius of Ricci scalar curvature, i.e. $R^{-1/2}$. We obtain the Equation of State (EoS) parameter $ω_D$, the deceleration parameter $q$ and the evolution of energy density parameter $Ω'_D$ of our model in a non-flat universe. Moreover, we study the limiting cases corresponding to our model without corrections and to the Einstein's gravity.

physics.gen-ph↗

arXiv2012

On the stability of the dark energy based on generalized uncertainty principle

The new agegraphic Dark Energy (NADE) model (based on generalized uncertainty principle) interacting with Dark Matter (DM) is considered in this study via power-law form of the scale factor $a(t)$. The equation of state (EoS) parameter $ω_{G}$ is observed to have a phantom-like behaviour. The stability of this model is investigated through the squared speed of sound $v_{s}^{2}$: it is found that $v_{s}^{2}$ always stays at negative level, which indicates instability of the considered model.

physics.gen-ph↗