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.

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 Taxonomy of Dark Energy Models

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 163
Author(s):  
Verónica Motta ◽  
Miguel A. García-Aspeitia ◽  
Alberto Hernández-Almada ◽  
Juan Magaña ◽  
Tomás Verdugo
Keyword(s):  
Dark Energy ◽  
Cold Dark Matter ◽  
Accelerated Expansion ◽  
Energy Component ◽  
The Past ◽  
Energy Models ◽  
The Status ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Unknown Component

The accelerated expansion of the Universe is one of the main discoveries of the past decades, indicating the presence of an unknown component: the dark energy. Evidence of its presence is being gathered by a succession of observational experiments with increasing precision in its measurements. However, the most accepted model for explaining the dynamic of our Universe, the so-called Lambda cold dark matter, faces several problems related to the nature of such energy component. This has led to a growing exploration of alternative models attempting to solve those drawbacks. In this review, we briefly summarize the characteristics of a (non-exhaustive) list of dark energy models as well as some of the most used cosmological samples. Next, we discuss how to constrain each model’s parameters using observational data. Finally, we summarize the status of dark energy modeling.

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 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.

DYNAMICS OF DARK ENERGY

2006 ◽  
Vol 15 (11) ◽  
pp. 1753-1935 ◽  
Author(s):  
EDMUND J. COPELAND ◽  
M. SAMI ◽  
SHINJI TSUJIKAWA
Keyword(s):  
Dark Energy ◽  
Particle Physics ◽  
Large Scale ◽  
Scalar Fields ◽  
Accelerated Expansion ◽  
Accelerating Universe ◽  
Late Time ◽  
Microwave Background ◽  
Energy Models ◽  
Expansion Of The Universe

We review in detail a number of approaches that have been adopted to try and explain the remarkable observation of our accelerating universe. In particular we discuss the arguments for and recent progress made towards understanding the nature of dark energy. We review the observational evidence for the current accelerated expansion of the universe and present a number of dark energy models in addition to the conventional cosmological constant, paying particular attention to scalar field models such as quintessence, K-essence, tachyon, phantom and dilatonic models. The importance of cosmological scaling solutions is emphasized when studying the dynamical system of scalar fields including coupled dark energy. We study the evolution of cosmological perturbations allowing us to confront them with the observation of the Cosmic Microwave Background and Large Scale Structure and demonstrate how it is possible in principle to reconstruct the equation of state of dark energy by also using Supernovae Ia observational data. We also discuss in detail the nature of tracking solutions in cosmology, particle physics and braneworld models of dark energy, the nature of possible future singularities, the effect of higher order curvature terms to avoid a Big Rip singularity, and approaches to modifying gravity which leads to a late-time accelerated expansion without recourse to a new form of dark energy.

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 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.

DARK ENERGY

2013 ◽  
Vol 22 (14) ◽  
pp. 1330027 ◽  
Author(s):  
DAVID POLARSKI
Keyword(s):  
Dark Energy ◽  
Accelerated Expansion ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
Similarities And Differences ◽  
The Universe ◽  
Physical Principles

Dark energy models account for the present accelerated expansion of the universe. Many models were suggested and investigated, based on very different physical principles. We will review some representative models emphasizing similarities and differences between these various approaches.

scholarly journals Dispersion relations for gravitational waves in different models of dark energy

2017 ◽  
Vol 26 (14) ◽  
pp. 1750157
Author(s):  
Vladimir Dzhunushaliev ◽  
Vladimir Folomeev ◽  
Burkhard Kleihaus ◽  
Jutta Kunz
Keyword(s):  
Dark Energy ◽  
Power Series ◽  
Gravitational Waves ◽  
Observational Data ◽  
Specific Model ◽  
Dispersion Relations ◽  
Accelerated Expansion ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
The Universe

The propagation of weak gravitational waves on the background of dark energy is studied. The consideration is carried out within the framework of an approximate approach where the cosmological scale factor is expanded as a power series for relatively small values of the redshift corresponding to the epoch of the present accelerated expansion of the universe. For several different dark energy models, we obtain dispersion relations for gravitational waves which can be used to estimate the viability of every specific model by comparing with observational data.

scholarly journals Ghost Chaplygin scalar field model of dark energy

2013 ◽  
Vol 91 (1) ◽  
pp. 54-59 ◽  
Author(s):  
F. Adabi ◽  
K. Karami ◽  
M. Mousivand
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Field Model ◽  
Accelerated Expansion ◽  
Scalar Field Model ◽  
Ghost Dark Energy ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Friedmann Robertson Walker

We investigate the correspondence between the ghost and Chaplygin scalar field dark energy models in the framework of Einstein gravity. We consider a spatially nonflat Friedmann–Robertson–Walker universe containing dark energy that interacts with dark matter. We reconstruct the potential and the dynamics for the Chaplygin scalar field model according to the evolutionary behavior of ghost dark energy, which can describe the phantomic accelerated expansion of the universe.

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