scholarly journals Modified gravity in the framework of holographic dark energy

2019 ◽  
Vol 35 (06) ◽  
pp. 2050025
Author(s):  
L. N. Granda ◽  
G. D. Rojas
Keyword(s):  
Dark Energy ◽  
Critical Points ◽  
Modified Gravity ◽  
Autonomous System ◽  
Holographic Dark Energy

The modified gravity is considered in the framework of the holographic dark energy (DE). An analysis of the autonomous system, the critical points and their stability is presented. Unlike the DE models based on [Formula: see text], it is found that working in the holographic frame enriches the possibility of accelerated and matter-type points for different cosmological scenarios, making viable trajectories of successful [Formula: see text] models that are not allowed without the consideration of the holographic framework. The implications for the Hu–Sawicki model are analyzed.

F(G) gravity models based on the ordinary and entropy-corrected holographic dark energy models

2013 ◽  
Vol 91 (2) ◽  
pp. 134-139
Author(s):  
M.R. Setare ◽  
B. Malakolkalami ◽  
N. Mohammadipour
Keyword(s):  
Dark Energy ◽  
Modified Gravity ◽  
Holographic Dark Energy ◽  
Gravity Models ◽  
Energy Models ◽  
Friedmann Robertson Walker ◽  
Modified Gravity Models

The ordinary and entropy-corrected versions of the holographic dark energy models in the spatially flat Friedmann–Robertson–Walker universe are considered. Then the F(G) modified gravity models as a candidates of dark energy are reconstructed according to the ordinary and entropy-corrected versions of the holographic dark energy models. The EoS parameters corresponding to the F(G) gravity models are obtained. The validity phantom or quintessence models in this framework of the modified gravity are investigated.

scholarly journals Ricci–Gauss–Bonnet holographic dark energy in Chern–Simons modified gravity: A flat FLRW quintessence-dominated universe

2019 ◽  
Vol 35 (05) ◽  
pp. 2050007 ◽  
Author(s):  
Nasr Ahmed
Keyword(s):  
Dark Energy ◽  
Modified Gravity ◽  
Holographic Dark Energy ◽  
Cosmic Time ◽  
Early Time ◽  
State Parameter ◽  
Late Time ◽  
Equation Of State Parameter ◽  
Chern Simons ◽  
Far Future

We discuss the recently suggested Ricci–Gauss–Bonnet holographic dark energy in Chern–Simons modified gravity. We have tested some general forms of the scale factor [Formula: see text], and used two physically reasonable forms which have been proved to be consistent with observations. Both solutions predict a sign flipping in the evolution of cosmic pressure which is positive during the early-time deceleration and negative during the late-time acceleration. This sign flipping in the evolution of cosmic pressure helps in explaining the cosmic deceleration–acceleration transition, and it has appeared in other cosmological models in different contexts. However, this work shows a pressure singularity which needs to be explained. The evolution of the equation of state parameter [Formula: see text] shows the same asymptotic behavior for both solutions indicating a quintessence-dominated universe in the far future. We also note that [Formula: see text] goes to negative values (leaving the decelerating dust-dominated era at [Formula: see text]) at exactly the same time the pressure becomes negative. Again, there is another singularity in the behavior of [Formula: see text] which happens at the same cosmic time of the pressure singularity.

Thermodynamics of specific modified gravity with generalized interaction term

2018 ◽  
Vol 15 (03) ◽  
pp. 1850033
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
Tanzeela Nawaz
Keyword(s):  
Dark Energy ◽  
Modified Gravity ◽  
Holographic Dark Energy ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Generalized Second Law ◽  
Energy Models ◽  
Interaction Term ◽  
Hubble Horizon ◽  
Chern Simons

We investigate the generalized second law of thermodynamics by assuming the interaction of dark energy and dark matter in Chern–Simons modified gravity. We consider a family of holographic dark energy models by assuming its various cutoffs such as Hubble horizon, event horizon, their combination, Ricci scalar and its generalized form. The general criteria of generalized second law of thermodynamics in terms of coincidence parameter is being developed. This criterion is being applied for the above-mentioned holographic dark energy models to check the validity of the generalized second law of thermodynamics and the constraints where it is respected are referred.

Entropy corrected holographic dark energy models in modified gravity

2017 ◽  
Vol 26 (04) ◽  
pp. 1750040 ◽  
Author(s):  
Abdul Jawad ◽  
Nadeem Azhar ◽  
Shamaila Rani
Keyword(s):  
Dark Energy ◽  
Modified Gravity ◽  
Cold Dark Matter ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Second Law Of Thermodynamics ◽  
Accelerated Expansion ◽  
Eos Parameter ◽  
Generalized Second Law ◽  
Expansion Of The Universe

We consider the power law and the entropy corrected holographic dark energy (HDE) models with Hubble horizon in the dynamical Chern–Simons modified gravity. We explore various cosmological parameters and planes in this framework. The Hubble parameter lies within the consistent range at the present and later epoch for both entropy corrected models. The deceleration parameter explains the accelerated expansion of the universe. The equation of state (EoS) parameter corresponds to quintessence and cold dark matter ([Formula: see text]CDM) limit. The [Formula: see text] approaches to [Formula: see text]CDM limit and freezing region in both entropy corrected models. The statefinder parameters are consistent with [Formula: see text]CDM limit and dark energy (DE) models. The generalized second law of thermodynamics remain valid in all cases of interacting parameter. It is interesting to mention here that our results of Hubble, EoS parameter and [Formula: see text] plane show consistency with the present observations like Planck, WP, BAO, [Formula: see text], SNLS and nine-year WMAP.

Generalized ghost Tsallis holographic dark energy model in RS-II braneworld and dynamical Chern-Simons modified gravity

2020 ◽  
Vol 17 (08) ◽  
pp. 2050124
Author(s):  
Abdul Jawad ◽  
Sabir Hussain ◽  
Shamaila Rani ◽  
Saba Qummer
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Modified Gravity ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Frw Universe ◽  
Om Diagnostic ◽  
Equation Of State Parameter ◽  
Chern Simons

In this paper, we studied the cosmological implications of generalized ghost Tsallis holographic dark energy in the framework of Randall–Sundrum II braneworld and Chern–Simons modified gravity in flat FRW universe. We discuss the cosmological parameters like equation of state parameter, deceleration parameter, squared speed of sound, Om-diagnostic and planes like evolving equation of state parameter and statefinders. These models yield useful results in this context.

scholarly journals THE COSMOLOGICAL DYNAMICS OF INTERACTING HOLOGRAPHIC DARK ENERGY MODEL

2009 ◽  
Vol 18 (01) ◽  
pp. 147-157 ◽  
Author(s):  
M. R. SETARE ◽  
ELIAS C. VAGENAS
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
Critical Points ◽  
Dark Energy Model ◽  
Holographic Dark Energy ◽  
Cosmic Acceleration ◽  
Holographic Dark Energy Model ◽  
Evolution Of The Universe ◽  
Energy Scenario ◽  
The Universe

Motivated by the recent observations for cosmic acceleration and the suitable evolution of the universe provided an interaction (decay of dark energy to matter) is incorporated in a cosmological model, we study the cosmological evolution of the interacting holographic dark energy scenario. Critical points are derived and their corresponding cosmological models are presented. The dynamical character of these models is revealed.

Non-flat FRW universe version of Tsallis holographic dark energy in specific modified gravity

2019 ◽  
Vol 34 (07n08) ◽  
pp. 1950055 ◽  
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
Nadeem Azhar
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Modified Gravity ◽  
Holographic Dark Energy ◽  
Apparent Horizon ◽  
State Parameter ◽  
Second Law Of Thermodynamics ◽  
Frw Universe ◽  
Generalized Second Law ◽  
The Stability

Among various dark energy models, Tsallis holographic dark energy model shows the dynamical enthusiasm to describe the transition phase of the universe. In this paper, we consider Tsallis holographic dark energy with event and apparent horizon as an infrared cutoff in the framework of dynamical Chern–Simon modified gravity and non-flat FRW universe. We explore Hubble, equation of state and deceleration parameters and found that Hubble parameter lies in the range [Formula: see text] and [Formula: see text] for event and apparent horizon trajectories, respectively. It is mentioned here that the equation of state parameter lies within the range [Formula: see text] (event) and [Formula: see text] (apparent). Also, deceleration parameter for both cases show accelerated and decelerated phase of universe as well as cosmological constant. Moreover, we also checked the stability of our model through square speed of sound, which shows the positive behavior (exhibits the stability of the model). Finally, we observe that the generalized second law of thermodynamics remains valid in both cases of horizon.

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