scholarly journals Interacting Rényi Holographic Dark Energy in the Brans-Dicke Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Vipin Chandra Dubey ◽  
Umesh Kumar Sharma ◽  
Abdulla Al Mamon
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Accelerated Expansion ◽  
Density Parameter ◽  
Late Time ◽  
Dark Energy Density ◽  
Expansion Phase ◽  
The Stability

In this work, we construct an interacting model of the Rényi holographic dark energy in the Brans-Dicke theory of gravity using Rényi entropy in a spatially flat Friedmann-Lemaître-Robertson-Walker Universe considering the infrared cut-off as the Hubble horizon. In this setup, we then study the evolutionary history of some important cosmological parameters, in particular, deceleration parameter, Hubble parameter, equation of state parameter, and Rényi holographic dark energy density parameter in both nonflat Universe and flat Universe scenarios and also observe satisfactory behaviors of these parameters in the model. We find that during the evolution, the present model can give rise to a late-time accelerated expansion phase for the Universe preceded by a decelerated expansion phase for both flat and nonflat cases. Moreover, we obtain ω D → − 1 as z → − 1 , which indicates that this model behaves like the cosmological constant at the future. The stability analysis for the distinct estimations of the Rényi parameter δ and coupling coefficient b 2 has been analyzed. The results indicate that the model is stable at the late time.

scholarly journals Barrow holographic dark energy with hubble horizon as IR cutoff

2020 ◽  
Vol 18 (01) ◽  
pp. 2150014
Author(s):  
Shikha Srivastava ◽  
Umesh Kumar Sharma
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Accelerated Expansion ◽  
Density Parameter ◽  
Eos Parameter ◽  
History Of ◽  
Hubble Horizon ◽  
Flrw Universe ◽  
The Stability

In this work, we propose a non-interacting model of Barrow holographic dark energy (BHDE) using Barrow entropy in a spatially flat FLRW Universe considering the IR cutoff as the Hubble horizon. We study the evolutionary history of important cosmological parameters, in particular, deceleration parameter, equation of state (EoS) parameter, the BHDE and matter density parameter, and also observe satisfactory behaviors in the BHDE model. The stability of the BHDE model has been examined by squared sound speed [Formula: see text]. In addition, to describe the accelerated expansion of the Universe, the correspondence of the BHDE model with the quintessence scalar field has been reconstructed.

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 Interacting Rényi holographic dark energy with parametrization on the interaction term

2021 ◽  
Author(s):  
Umesh Kumar Sharma ◽  
Vipin Chandra Dubey
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Accelerated Expansion ◽  
Model Parameters ◽  
Density Parameter ◽  
Late Time ◽  
Frw Universe ◽  
Eos Parameter ◽  
Interaction Term

In this work, we study the Rényi holographic dark energy (RHDE) model in a flat FRW Universe where the infrared cut-off is taken care by the Hubble horizon and also by taking three different parametrizations of the interaction term between the dark matter and the dark energy. Analyzing graphically, the behavior of some cosmological parameters in particular deceleration parameter, equation of state (EoS) parameter, energy density parameter and squared speed of sound, in the process of the cosmic evolution, is found to be leading towards the late-time accelerated expansion of the RHDE model. Also, we find the departure for the derived models from the standard [Formula: see text]CDM model according to the evolution of jerk parameter. Moreover, we compare the model parameters by considering the observational Hubble data which consist of 51 points in the redshift range [Formula: see text].

scholarly journals Braneworld Inspires Cosmological Implications of Barrow Holographic Dark Energy

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 268
Author(s):  
Shamaila Rani ◽  
Nadeem Azhar
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Speed Of Sound ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Accelerated Expansion ◽  
Late Time ◽  
Freezing And Thawing ◽  
Event Horizons

In the present manuscript, the evolution of the cosmic parameters and planes are being investigated in the framework of the DGP braneworld model. In this scenario, the interaction Γ between the Barrow holographic dark energy model (whose infrared cutoff scale is set by Hubble and event horizons) and pressureless dark matter are considered. We check the behavior of different cosmological parameters such as Hubble, equation of state, deceleration and squared speed of sound from the early matter-dominated era until the late-time acceleration. It is found that the range of Hubble parameter lies in the interval 95−35+35 (for Hubble horizon) and 97−23+23 (for event horizon). For both horizons, the equation of state parameter favors the phantom dominant era as well as the ΛCDM model while the deceleration parameter illustrates the accelerated expansion of the universe. Furthermore, stability of the underlying model is found through squared speed of sound. Furthermore, it is observed that ω−ωϑ′ plane corresponds to freezing and thawing region for Hubble and event horizons, respectively. Furthermore, statefinder plane shows the ΛCDM and Chaplygin gas behavior for both models. Finally, we investigate the thermodynamical nature of the underlying model through Barrow entropy as horizon entropy and found validity for both horizons.

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.

Power-law entropy-corrected new holographic dark energy in Brans–Dicke cosmology

2015 ◽  
Vol 93 (4) ◽  
pp. 475-480 ◽  
Author(s):  
Bharat Borah ◽  
M. Ansari
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Power Law ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Dark Energy Density ◽  
Cosmological Application ◽  
Expansion Of The Universe ◽  
Limiting Case

The purpose of this paper is to study power-law entropy-corrected holographic dark energy (PLECHDE) in the framework of Brans–Dicke cosmology with Granda–Oliveros (G-O) IR-cutoff. Considering the interacting and non-interacting scenario of PLECHDE with dark matter, we investigate the cosmological implications of this model in detail. We obtain the equation of state parameter, deceleration parameter, and evolution of dark energy density to explain expansion of the universe. We also determine these parameters for Ricci scale. We extend our study of the power-law entropy-corrected agegraphic dark energy model and calculate some cosmological parameters. Further, we show that the results that we calculate have good compatibility with previous work and matches it in the limiting case. Finally, we find a cosmological application of our work by evaluating the equation of state of dark energy for low red-shift.

Ghost dark energy in the deformed Hořava–Lifshitz cosmology

2019 ◽  
Vol 28 (06) ◽  
pp. 1950080
Author(s):  
A. Sheykhi ◽  
S. Ghaffari ◽  
H. Moradpour
Keyword(s):  
Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Density Parameter ◽  
Late Time ◽  
Ghost Dark Energy ◽  
Deceleration Phase ◽  
Classical Stability ◽  
Equation Of State Parameter ◽  
Generalized Ghost Dark Energy

We study the cosmological consequences of the ghost models of dark energy (DE) in the framework of Hořava–Lifshitz gravity. We calculate the equation-of-state parameter, the deceleration parameter, the classical stability and the dimensionless density parameter of the models in both noninteracting and interacting scenarios. We find that, for some values of the parameter, this model can admit a transition from the deceleration phase to the accelerated phase around [Formula: see text], while at the late time ([Formula: see text]) we have [Formula: see text] meaning that this model mimics a cosmological constant. We find that in the setup of Hořava–Lifshitz gravity, ghost dark energy (GDE) models are classically unstable. We observe that unlike the generalized ghost dark energy (GGDE), the ghost dark energy cannot provide proper behavior for all the cosmological parameters simultaneously, with the same values of the models’ couplings.

scholarly journals Tsallis holographic dark energy in fractal universe

2020 ◽  
Vol 35 (14) ◽  
pp. 2050107 ◽  
Author(s):  
S. Ghaffari ◽  
E. Sadri ◽  
A. H. Ziaie
Keyword(s):  
Dark Energy ◽  
Gamma Ray ◽  
Holographic Dark Energy ◽  
Accelerating Universe ◽  
Density Parameter ◽  
Late Time ◽  
Dark Energy Density ◽  
Eos Parameter ◽  
Deceleration Phase ◽  
Hubble Radius

We study the cosmological consequences of interacting Tsallis holographic dark energy model in the framework of the fractal universe in which the Hubble radius is considered as the IR cutoff. We derive the equation of state (EoS) parameter, deceleration parameter and the evolution equation for the Tsallis holographic dark energy density parameter. Our study shows that this model can describe the current accelerating universe in both non-interacting and interacting scenarios, and also a transition occurs from the deceleration phase to the accelerated phase at the late-time. Finally, we check the compatibility of free parameters of the model with the latest observational results by using the Pantheon supernovae data, eBOSS, 6df, BOSS DR12, CMB Planck 2015, Gamma-Ray Burst.

Rényi holographic dark energy in the Brans–Dicke cosmology

2020 ◽  
Vol 35 (34) ◽  
pp. 2050281
Author(s):  
Umesh Kumar Sharma ◽  
Vipin Chandra Dubey
Keyword(s):  
Dark Energy ◽  
Stability Analysis ◽  
Equation Of State ◽  
Deceleration Parameter ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Density Parameter ◽  
Eos Parameter ◽  
Hubble Horizon ◽  
The Stability

In this paper, we construct a holographic dark energy (HDE) model considering the IR cut-off as Hubble horizon, holographic hypothesis, and using the generalized Rényi entropy, and investigate its cosmological outcomes in Brans–Dicke gravity without interaction. We observe the suitable behavior for the cosmological parameters, involving the deceleration parameter, the equation of state (EoS) parameter, and the density parameter in both flat and non-flat Universes. It is also concluded by the stability analysis that the Rényi holographic dark energy (RHDE) model is classically stable at present and future for the Rényi parameter [Formula: see text] in both flat and non-flat Universe.

scholarly journals A generalized interacting Tsallis holographic dark energy model and its thermodynamic implications

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Abdulla Al Mamon ◽  
Amir Hadi Ziaie ◽  
Kazuharu Bamba
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Hubble Parameter ◽  
Holographic Dark Energy ◽  
State Parameter ◽  
Density Parameter ◽  
Special Cases ◽  
Present Context ◽  
The Stability ◽  
The Universe

AbstractThe present paper deals with a theoretical model for interacting Tsallis holographic dark energy (THDE) whose infrared cut-off scale is set by the Hubble length. The interaction Q between the dark sectors (dark energy and pressureless dark matter) of the universe has been assumed to be non-gravitational in nature. The functional form of Q is chosen in such a way that it reproduces well known and most used interactions as special cases. We then study the nature of the THDE density parameter, the equation of state parameter, the deceleration parameter and the jerk parameter for this interacting THDE model. Our study shows that the universe exhibits the usual thermal history, namely the successive sequence of radiation, dark matter and dark energy epochs, before resulting in a complete dark energy domination in the far future. It is shown the evolution of the Hubble parameter for our model and compared that with the latest Hubble parameter data. Finally, we also investigate both the stability and thermodynamic nature of this model in the present context.

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