ENTROPY CORRECTED HOLOGRAPHIC DARK ENERGY f(T) GRAVITY MODEL

2014 ◽  
Vol 29 (02) ◽  
pp. 1450015 ◽  
Author(s):  
M. SHARIF ◽  
SHAMAILA RANI
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Phase Plane ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Accelerated Expansion ◽  
Statefinder Parameters ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Evolution Trajectory

This paper is devoted to study the power-law entropy corrected holographic dark energy (ECHDE) model in the framework of f(T) gravity. We assume infrared (IR) cutoff in terms of Granda–Oliveros (GO) length and discuss the constructed f(T) model in interacting as well as in non-interacting scenarios. We explore some cosmological parameters like equation of state (EoS), deceleration, statefinder parameters as well as ωT–ωT′ analysis. The EoS and deceleration parameters indicate phantom behavior of the accelerated expansion of the universe. It is mentioned here that statefinder trajectories represent consistent results with ΛCDM limit, while evolution trajectory of ωT–ωT′ phase plane does not approach to ΛCDM limit for both interacting and non-interacting cases.

scholarly journals Cosmic Consequences of Kaniadakis and Generalized Tsallis Holographic Dark Energy Models in the Fractal Universe

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Abdul Jawad ◽  
Abdul Malik Sultan
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Apparent Horizon ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Accelerated Expansion ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
The Stability ◽  
The Universe

We investigate the recently proposed holographic dark energy models with the apparent horizon as the IR cutoff by assuming Kaniadakis and generalized Tsallis entropies in the fractal universe. The implications of these models are discussed for both the interacting ( Γ = 3 H b 2 ρ m ) and noninteracting ( b 2 = 0 ) cases through different cosmological parameters. Accelerated expansion of the universe is justified for both models through deceleration parameter q . In this way, the equation of state parameter ω d describes the phantom and quintessence phases of the universe. However, the coincidence parameter r ~ = Ω m / Ω d shows the dark energy- and dark matter-dominated eras for different values of parameters. It is also mentioned here that the squared speed of sound gives the stability of the model except for the interacting case of the generalized Tsallis holographic dark energy model. It is mentioned here that the current dark energy models at the apparent horizon give consistent results with recent observations.

scholarly journals PRESENT ACCELERATION OF THE UNIVERSE, HOLOGRAPHIC ENERGY AND BRANS–DICKE THEORY

2009 ◽  
Vol 24 (22) ◽  
pp. 1785-1792 ◽  
Author(s):  
B. NAYAK ◽  
L. P. SINGH
Keyword(s):  
Dark Energy ◽  
Power Law ◽  
Dark Energy Model ◽  
Holographic Dark Energy ◽  
Accelerated Expansion ◽  
Temporal Behavior ◽  
Holographic Dark Energy Model ◽  
Acceleration Of The Universe ◽  
Expansion Of The Universe ◽  
The Universe

The present-day accelerated expansion of the universe is naturally addressed within the Brans–Dicke theory just by using holographic dark energy model with inverse of Hubble scale as IR cutoff and power law temporal behavior of scale factor. It is also concluded that if the universe continues to expand, then one day it might be completely filled with dark energy.

scholarly journals DARK ENERGY: A UNIFYING VIEW

2008 ◽  
Vol 17 (03n04) ◽  
pp. 651-658 ◽  
Author(s):  
WINFRIED ZIMDAHL
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Interaction Strength ◽  
Chaplygin Gas ◽  
Accelerated Expansion ◽  
Strength Parameter ◽  
Expansion Of The Universe ◽  
Pressure Perturbations ◽  
The Universe

Different models of the cosmic substratum which pretend to describe the present stage of accelerated expansion of the Universe, like the ΛCDM model or the Chaplygin gas, can be seen as special realizations of a holographic dark energy cosmology if the option of an interaction between pressureless dark matter and dark energy is taken seriously. The corresponding interaction strength parameter plays the role of a cosmological constant. Differences occur at the perturbative level. In particular, the pressure perturbations are intrinsically nonadiabatic.

scholarly journals Dynamical Properties of Dark Energy Models in Fractal Universe

Symmetry ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1174
Author(s):  
Muhammad Umair Shahzad ◽  
Ayesha Iqbal ◽  
Abdul Jawad
Keyword(s):  
Dark Energy ◽  
State Parameter ◽  
Accelerated Expansion ◽  
Accelerating Universe ◽  
Statefinder Parameters ◽  
Om Diagnostic ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
Dynamical Properties ◽  
The Universe

In this paper, we consider the flat FRW spacetime filled with interacting dark energy and dark matter in fractal universe. We work with the three models of dark energy named as Tsallis, Renyi and Sharma–Mittal. We investigate different cosmological implications such as equation of state parameter, squared speed of sound, deceleration parameter, statefinder parameters, ω e f f - ω e f f ´ (where prime indicates the derivative with respect to ln a , and a is cosmic scale factor) plane and Om diagnostic. We explore these parameters graphically to study the evolving universe. We compare the consistency of dark energy models with the accelerating universe observational data. All three models are stable in fractal universe and support accelerated expansion of the universe.

THREE COMPONENTS EVOLUTION IN A SIMPLE BIG BOUNCE COSMOLOGICAL MODEL

2005 ◽  
Vol 14 (05) ◽  
pp. 883-891 ◽  
Author(s):  
LIXIN XU ◽  
HONGYA LIU
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Cosmological Model ◽  
Accelerated Expansion ◽  
Ricci Flat ◽  
Bouncing Cosmology ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Three Components ◽  
Big Bounce

We consider a five-dimensional Ricci flat Bouncing cosmology and assume that the four-dimensional universe is permeated smoothly by three minimally coupled matter components: CDM + baryons ρm, radiation ρr and dark energy ρx. Evolutions of these three components are studied and it is found that dark energy dominates before the bounce, and pulls the universe contracting. In this process, dark energy decreases while radiation and the matter increases. After the bounce, the radiation and matter dominates alternatively and then decreases with the expansion of the universe. At present, the dark energy dominates again and pushes the universe accelerating. In this model, we also obtain that the equation of state (EOS) of dark energy at present time is wx0≈-1.05 and the redshift of the transition from decelerated expansion to accelerated expansion is zT≈0.37, which are compatible with the current observations.

scholarly journals Cosmic Evolution of Holographic Dark Energy in f(G,T) Gravity

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
M. Sharif ◽  
Ayesha Ikram
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Phase Plane ◽  
Holographic Dark Energy ◽  
State Parameter ◽  
Momentum Tensor ◽  
Chaplygin Gas ◽  
Cosmic Evolution ◽  
Evolutionary Trajectories ◽  
The Universe

The aim of this paper is to analyze the cosmological evolution of holographic dark energy in f(G,T) gravity (G and T represent the Gauss-Bonnet invariant and trace of the energy-momentum tensor, respectively). We reconstruct f(G,T) model through correspondence scheme using power-law form of the scale factor. The qualitative analysis of the derived model is investigated with the help of evolutionary trajectories of equation of state and deceleration as well as state-finder diagnostic parameters and ωGT-ωGT′ cosmological phase plane. It is found that the equation of state parameter represents phantom epoch of the Universe whereas the deceleration parameter illustrates the accelerated phase. The state-finder plane corresponds to Chaplygin gas model while the freezing region is attained in ωGT-ωGT′ plane.

scholarly journals STATEFINDER DIAGNOSTIC FOR DARK ENERGY MODELS IN BIANCHI I UNIVERSE

2012 ◽  
Vol 21 (05) ◽  
pp. 1250046 ◽  
Author(s):  
M. SHARIF ◽  
RABIA SALEEM
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Chaplygin Gas ◽  
Accelerated Expansion ◽  
Ricci Dark Energy ◽  
Generalized Chaplygin Gas ◽  
Bianchi I ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
The Universe

In this paper, we investigate the statefinder, the deceleration and equation of state parameters when universe is composed of generalized holographic dark energy or generalized Ricci dark energy for Bianchi I universe model. These parameters are found for both interacting as well as noninteracting scenarios of generalized holographic or generalized Ricci dark energy with dark matter and generalized Chaplygin gas. We explore these parameters graphically for different situations. It is concluded that these models represent accelerated expansion of the universe.

scholarly journals Barrow HDE model for statefinder diagnostic in FLRW universe

2021 ◽  
pp. 2150030
Author(s):  
Anirudh Pradhan ◽  
Archana Dixit ◽  
Vinod Kumar Bhardwaj
Keyword(s):  
Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Accelerated Expansion ◽  
Density Parameter ◽  
Phantom Divide ◽  
Phantom Divide Line ◽  
Expansion Of The Universe ◽  
Flrw Universe ◽  
The Universe

We have analyzed the Barrow holographic dark energy (BHDE) in the framework of flat FLRW universe by considering the various estimations of Barrow exponent △. Here, we define BHDE, by applying the usual holographic principle at a cosmological system, for utilizing the Barrow entropy rather than the standard Bekenstein–Hawking. To understand the recent accelerated expansion of the universe, consider the Hubble horizon as the IR cutoff. The cosmological parameters, especially the density parameter [Formula: see text], the equation of the state parameter [Formula: see text], energy density [Formula: see text] and the deceleration parameter [Formula: see text] are studied in this paper and found the satisfactory behaviors. Moreover we additionally focus on the two geometric diagnostics, the statefinder [Formula: see text] and [Formula: see text] to discriminant BHDE model from the [Formula: see text]CDM model. Here we determined and plotted the trajectories of evolution for statefinder [Formula: see text], [Formula: see text] and [Formula: see text] diagnostic plane to understand the geometrical behavior of the BHDE model by utilizing Planck 2018 observational information. Finally, we have explored the new Barrow exponent △, which strongly affects the dark energy equation of state that can lead it to lie in the quintessence regime, phantom regime and exhibits the phantom-divide line during the cosmological evolution.

scholarly journals Observational constraints and stability in viscous gravity

2020 ◽  
Vol 98 (12) ◽  
pp. 1119-1124
Author(s):  
T. Mirzaei Rezaei ◽  
Alireza Amani ◽  
E. Yusofi ◽  
S. Rouhani ◽  
M.A. Ramzanpour
Keyword(s):  
Dark Energy ◽  
Cosmological Parameters ◽  
Teleparallel Gravity ◽  
System Stability ◽  
Accelerated Expansion ◽  
Tetrad Field ◽  
Dark Energy Component ◽  
Walker Metric ◽  
Expansion Of The Universe ◽  
The Universe

In this paper, we study the [Formula: see text] gravity model in the presence of bulk viscosity by the flat Friedmann–Robertson–Walker metric. The field equation is obtained by teleparallel gravity with a tetrad field. The universe components are considered matter and dark energy, with the dark energy component associated with viscous [Formula: see text] gravity. After calculating the Friedmann equations, we obtain the energy density, pressure, and equation of state of dark energy in terms of the redshift parameter. Afterward, we plot the corresponding cosmological parameters versus the redshift parameter and examine the accelerated expansion of the universe. In the end, we explore the system stability using a function called the speed sound parameter.

scholarly journals RECONSTRUCTION OF MODIFIED GRAVITY WITH GHOST DARK ENERGY MODELS

2012 ◽  
Vol 27 (18) ◽  
pp. 1250100 ◽  
Author(s):  
A. KHODAM-MOHAMMADI ◽  
M. MALEKJANI ◽  
M. MONSHIZADEH
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Modified Gravity ◽  
Deceleration Parameter ◽  
Accelerated Expansion ◽  
Ghost Dark Energy ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Generalized Ghost Dark Energy

In this work, we reconstruct the f(R) modified gravity for different ghost and generalized-ghost dark energy (DE) models in FRW flat universe, which describes the accelerated expansion of the universe. The equation of state and deceleration parameter of reconstructed f(R) gravity have been calculated. The equation of state and deceleration parameter of reconstructed f(R)-ghost/generalized-ghost DE, have been calculated. We show that the corresponding f(R) gravity of ghost/generalized-ghost DE model can behave like phantom or quintessence. Also the transition between deceleration to acceleration regime is indicated by deceleration parameter diagram for reconstructed f(R) generalized-ghost DE model.

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