Generalized ghost pilgrim dark energy in f(G,T) gravity

2019 ◽  
Vol 28 (06) ◽  
pp. 1950077 ◽  
Author(s):  
M. Sharif ◽  
Saadia Saba
Keyword(s):  
Dark Energy ◽  
State Parameter ◽  
Momentum Tensor ◽  
Chaplygin Gas ◽  
Frw Universe ◽  
Pilgrim Dark Energy ◽  
Energy Formula ◽  
Text Model ◽  
The Universe ◽  
Friedmann Robertson Walker

In this paper, we explore the reconstruction paradigm for generalized ghost pilgrim dark energy model with [Formula: see text] gravity ([Formula: see text] is the Gauss–Bonnet invariant and [Formula: see text] is the trace of the energy–momentum tensor) depending upon the speculation of black hole-free universe. To accomplish this, we adopt correspondence scheme for dust fluid configuration with flat Friedmann-Robertson-Walker (FRW) universe. The cosmic behavior of reconstructed models is examined through cosmological diagnostic parameters and phase planes. It is found that the deceleration parameter indicates accelerated phase while equation-of-state parameter represents phantom regime for some specific range of free parameters. The squared speed of sound parameter gives stable models for analyzing evolutionary paradigm of the universe. The trajectories of [Formula: see text]–[Formula: see text] plane gives thawing region, whereas [Formula: see text]–[Formula: see text] phase plane corresponds to Chaplygin gas model. We conclude that the resulting model represents self-consistent phantom-like universe for [Formula: see text] cannot be fraction) as well as stable generalized ghost pilgrim dark energy [Formula: see text] model.

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 Tsallis Holographic Dark Energy in f(G,T) Gravity

Symmetry ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 92 ◽  
Author(s):  
Muhammad Sharif ◽  
Saadia Saba
Keyword(s):  
Dark Energy ◽  
Energy Momentum Tensor ◽  
Holographic Dark Energy ◽  
State Parameter ◽  
Momentum Tensor ◽  
Chaplygin Gas ◽  
Holographic Dark Energy Model ◽  
Phantom Phase ◽  
Friedmann Robertson Walker ◽  
Fluid Configuration

In this paper, we study the reconstruction paradigm for Tsallis holographic dark energy model using generalized Tsallis entropy conjecture with Hubble horizon in the framework of f ( G , T ) gravity (G and T represent the Gauss-Bonnet invariant and trace of the energy-momentum tensor). We take the flat Friedmann-Robertson-Walker universe model with dust fluid configuration. The cosmological evolution of reconstructed models is examined through cosmic diagnostic parameters and phase planes. The equation of the state parameter indicates phantom phase while the deceleration parameter demonstrates accelerated cosmic epoch for both conserved as well as non-conserved energy-momentum tensor. The squared speed of the sound parameter shows instability of the conserved model while stable non-conserved model for the entire cosmic evolutionary paradigm. The trajectories of the ω G T - ω G T ′ plane correspond to freezing as well as thawing regimes for the conserved and non-conserved scenario, respectively. The r - s plane gives phantom and quintessence dark energy epochs for conserved while Chaplygin gas model regime for the non-conserved case. We conclude that, upon the appropriate choice of the free parameters involved, the derived models demonstrate a self-consistent phantom universe behavior.

Pilgrim dark energy in f(G, T) gravity

2018 ◽  
Vol 33 (31) ◽  
pp. 1850182 ◽  
Author(s):  
M. Sharif ◽  
Saadia Saba
Keyword(s):  
Dark Energy ◽  
Phase Plane ◽  
State Parameter ◽  
Chaplygin Gas ◽  
S Phase ◽  
Stable Model ◽  
Frw Universe ◽  
Pilgrim Dark Energy ◽  
Reconstructed Model ◽  
Fluid Configuration

In this paper, we analyze the reconstruction paradigm for pilgrim dark energy model with f(G, T) gravity using Hubble horizon as IR-cutoff. To accomplish this, we use correspondence scheme for dust fluid configuration with flat FRW universe. The cosmological behavior of reconstructed model is examined through cosmic diagnostic parameters and phase planes. It is found that the deceleration parameter indicates accelerated phase while equation of state parameter represents phantom regime. The squared speed of sound parameter gives stable model for analyzing current cosmic evolutionary paradigm. The trajectories of [Formula: see text] plane gives the thawing region, whereas r[Formula: see text]s phase plane corresponds to Chaplygin gas model. We conclude that the resulting model represents aggressive phantom-like universe for u[Formula: see text]0 (with odd choices only), as well as self-consistent PDE f(G, T) model.

Viability of specific reconstructed f(T,𝒯 ) models

2019 ◽  
Vol 34 (30) ◽  
pp. 1950184
Author(s):  
M. Umair Shahzad ◽  
Nadeem Azhar ◽  
Abdul Jawad ◽  
Shamaila Rani
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Dark Energy Model ◽  
State Parameter ◽  
Pilgrim Dark Energy ◽  
Ghost Dark Energy ◽  
Energy Models ◽  
Equation Of State Parameter ◽  
Hubble Horizon ◽  
The Universe

The reconstruction scenario of well-established dark energy models such as pilgrim dark energy model and generalized ghost dark energy with Hubble horizon and [Formula: see text] models is being considered. We have established [Formula: see text] models and analyzed their viability through equation of state parameter and [Formula: see text] (where prime denotes derivative with respect to [Formula: see text]) plane. The equation of state parameter evolutes the universe in three different phases such as quintessence, vacuum and phantom. However, the [Formula: see text] plane also describes the thawing as well as freezing region of the universe. The recent observational data also favor our results.

Various dark energy models for variables G and Λ in f(R, T) modified theory

2019 ◽  
Vol 34 (13) ◽  
pp. 1950098 ◽  
Author(s):  
Can Aktaş
Keyword(s):  
Dark Energy ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Tachyon Field ◽  
Field Equations ◽  
Frw Universe ◽  
Linearly Varying Deceleration Parameter ◽  
Energy Models ◽  
Modified Theory ◽  
Friedmann Robertson Walker

In this paper, we have researched tachyon field, k-essence and quintessence dark energy (DE) models for Friedmann–Robertson–Walker (FRW) universe with varying G and [Formula: see text] in f(R, T) gravitation theory. The theory of f(R, T) is proposed by Harko et al. [Phys. Rev. D 84, 024020, 2011]. In this theory, R is the Ricci scalar and T is the trace of energy–momentum tensor. For the solutions of field equations, we have used linearly varying deceleration parameter (LVDP), the equation of state (EoS) and the ratio between [Formula: see text] and Hubble parameter. Also, we have discussed some physical behavior of the models with various graphics.

scholarly journals The cosmological behavior and the statefinder diagnosis for the New Tsallis agegraphic dark energy

2020 ◽  
Vol 35 (38) ◽  
pp. 2050318
Author(s):  
Umesh Kumar Sharma ◽  
Shikha Srivastava
Keyword(s):  
Dark Energy ◽  
Dynamical Analysis ◽  
Current Phase ◽  
Statefinder Parameters ◽  
Frw Universe ◽  
Eos Parameter ◽  
Agegraphic Dark Energy ◽  
Evolutionary Trajectories ◽  
The Universe ◽  
Friedmann Robertson Walker

In this work, we have considered the recently proposed new Tsallis agegraphic dark energy (NTADE) model [Mod. Phys. Lett. A 34, 1950086 (2019)] within the framework of a flat Friedmann–Robertson–Walker (FRW) Universe by taking various values of the parameter [Formula: see text]. The NTADE model shows the current phase transition of the Universe from decelerated to accelerated phase. The NTADE equation of state (EoS) parameter shows a rich behavior as it can be quintessence-like or phantom-like depending on the value of [Formula: see text]. For discriminating the NTADE model from [Formula: see text]CDM, we have plotted the statefinder parameters [Formula: see text], [Formula: see text] and [Formula: see text], [Formula: see text] pair. The NTADE model shows distinct evolutionary trajectories of their evolution in ([Formula: see text]) and ([Formula: see text]) plane. An analysis using the snap parameter and the [Formula: see text] pair dynamical analysis have also been performed.

Generalized ghost pilgrim dark energy in F(T,TG) cosmology

2016 ◽  
Vol 31 (25) ◽  
pp. 1650148 ◽  
Author(s):  
M. Sharif ◽  
Kanwal Nazir
Keyword(s):  
Dark Energy ◽  
Scale Factor ◽  
The Other ◽  
Frw Universe ◽  
Eos Parameter ◽  
Pilgrim Dark Energy ◽  
Pde Model ◽  
Scale Factors ◽  
Two Phases ◽  
Friedmann Robertson Walker

This paper is devoted to study the generalized ghost pilgrim dark energy (PDE) model in [Formula: see text] gravity with flat Friedmann–Robertson–Walker (FRW) universe. In this scenario, we reconstruct [Formula: see text] models and evaluate the corresponding equation of state (EoS) parameter for different choices of the scale factors. We assume power-law scale factor, scale factor for unification of two phases, intermediate and bouncing scale factor. We study the behavior of reconstructed models and EoS parameters graphically. It is found that all the reconstructed models show decreasing behavior for PDE parameter [Formula: see text]. On the other hand, the EoS parameter indicates transition from dust-like matter to phantom era for all choices of the scale factor except intermediate for which this is less than [Formula: see text]. We conclude that all the results are in agreement with PDE phenomenon.

scholarly journals Sign-changeable interacting agegraphic dark energy in Brans–Dicke cosmology

2020 ◽  
Vol 98 (7) ◽  
pp. 643-649
Author(s):  
M. Abdollahi Zadeh ◽  
A. Sheykhi
Keyword(s):  
Dark Energy ◽  
State Parameter ◽  
The State ◽  
Evolutionary Equation ◽  
Model Parameters ◽  
Late Time ◽  
Frw Universe ◽  
Agegraphic Dark Energy ◽  
Deceleration Phase ◽  
The Universe

We explore a spatially homogeneous and isotropic Friedmann–Robertson–Walker (FRW) universe that is filled with agegraphic dark energy (ADE) with mutual interaction with pressureless dark matter in the background of Brans–Dicke (BD) theory. We consider both original and a new type of ADE (NADE) and further assume that the sign of the interaction term can change during the history of the universe. We obtain the equation of the state parameter, the deceleration parameter, and the evolutionary equation for the sign-changeable interacting ADE and NADE in BD cosmology. We find that in both models, the equation of the state parameter, wD, cannot cross the phantom line, although they can predict the universe evolution from the early deceleration phase to the late time acceleration, compatible with observations. We also investigate the sound stability of these models and find out that both models cannot show a signal of stability for different model parameters.

FRW universe in f(R,T) gravity

2021 ◽  
pp. 2150104
Author(s):  
R. K. Tiwari ◽  
D. Sofuoğlu ◽  
A. Beesham
Keyword(s):  
Phase Transition ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Field Equations ◽  
Frw Universe ◽  
Expansion Phase ◽  
Age Of The Universe ◽  
The Universe ◽  
Modified Theory ◽  
Friedmann Robertson Walker

In this study, Friedmann–Robertson–Walker space-time filled with a perfect fluid in [Formula: see text] modified theory, where [Formula: see text] is the Ricci scalar and [Formula: see text] is the trace of the energy–momentum tensor of matter, has been considered. The investigation of the phase transition of the universe from the decelerating expansion phase to the accelerating one has been made by adopting a special form of the varying deceleration parameter that is inversely proportional to the Hubble parameter. The exact solution of the field equations has been derived. The kinematic and dynamical quantities of the model have been obtained and their evolutions have been discussed by means of their graphs. The statefinder diagnostic has been used and the age of the universe has been computed for testing the validity of the model. It has been shown that the dominant energy of the model is ordinary matter which behaves as the SCDM model at the beginning and it is a quintessence like fluid which behaves as the [Formula: see text]CDM model at late times.

Dark energy model in higher-dimensional FRW universe with respect to generalized entropy of Sharma and Mittal of flat FRW space–time

2019 ◽  
Vol 97 (11) ◽  
pp. 1185-1186 ◽  
Author(s):  
E.C. Gunay Demirel
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
State Parameter ◽  
Space Time ◽  
Observational Evidence ◽  
The State ◽  
Frw Universe ◽  
Generalized Entropy ◽  
Higher Dimensional ◽  
Friedmann Robertson Walker

In this study, we report the state parameter of dark energy in higher dimensional Friedmann–Robertson–Walker (FRW) space–time according to generalized entropy of Sharma and Mittal. In this case we analyze the state parameter of dark energy according to today’s observational evidence.

Sign in / Sign up

Export Citation Format

Share Document