Interacting modified Chaplygin gas in f(T) gravity framework and analysis of its stability against gravitational perturbation

2017 ◽  
Vol 14 (03) ◽  
pp. 1750035 ◽  
Author(s):  
Surajit Chattopadhyay
Keyword(s):  
Modified Gravity ◽  
Cosmic Time ◽  
Chaplygin Gas ◽  
Gravitational Perturbation ◽  
Modified Chaplygin Gas ◽  
Coupling Constant ◽  
Eos Parameter ◽  
Cosmological Application ◽  
Text Model ◽  
Interaction Term

In this work, we investigate the cosmological application of modified Chaplygin gas (MCG) interacting with pressureless dark matter (DM) in the [Formula: see text] modified gravity framework, where [Formula: see text] is the torsion scalar in teleparallelism. The interaction term has been chosen proportional to the MCG density with positive coupling constant. In the Einstein general relativity (GR) framework, the interacting MCG has been found to have equation of state (EoS) parameter behaving like quintessence. However, the [Formula: see text] gravity reconstructed via the interacting MCG has been found to have EoS crossing the phantom boundary of [Formula: see text]. Thus, one can generate a quintom-like EoS from an interacting MCG model in flat universe in the modified gravity cosmology framework. The reconstructed [Formula: see text] model has been found to interpolate between dust and [Formula: see text]CDM. Stability of the reconstructed [Formula: see text] has been investigated and it has been observed that the model is stable against gravitational perturbation. Cosmological evolution of primordial perturbations has also been investigated and the self-interacting potential has been found to increase with cosmic time and the squared speed of sound has been found to be non-negative.

scholarly journals A study of modified holographic Ricci dark energy in the framework of f(T) modified gravity and its statefinder hierarchy

2019 ◽  
Vol 97 (5) ◽  
pp. 477-486 ◽  
Author(s):  
Arkaprabha Majumdar ◽  
Surajit Chattopadhyay
Keyword(s):  
Dark Matter ◽  
Fixed Point ◽  
Dark Energy ◽  
Modified Gravity ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Ricci Dark Energy ◽  
Eos Parameter ◽  
The Universe ◽  
Viable Model

Inspired by the work of Bamba et al. (Phys. Rev. D, 85, 104036 (2012)) the present paper reports a study on the reconstruction of modified holographic Ricci dark energy (MHRDE) in the framework of modified gravity taken as f(T) gravity. A correspondence between modified Chaplygin gas and MHRDE has also been considered and thereinafter the f(T) gravity has been reconstructed via reconstruction of the Hubble parameter. The reconstructed equation of state (EoS) parameter obtained this way has been found to be able to cross the phantom boundary. In the next phase of the work, a viable model of f(T) gravity has been considered and MHRDE has been discussed in this modified gravity frame. The EoS parameter due to the torsion contribution obtained this way has been found to behave like quintessence. The transition of the universe from the dark matter dominated to dark energy (DE) dominated phase is apparent from this model. Also, the model is exhibiting DE domination of the current universe. Finally, the statefinder hierarchy has been discussed through the statefinder and snap parameters. The model has been found to be able to attain the ΛCDM fixed point in the statefinder trajectory.

A study on the bouncing behavior of modified Chaplygin gas in presence of bulk viscosity and its consequences in the modified gravity framework

2017 ◽  
Vol 14 (12) ◽  
pp. 1750181 ◽  
Author(s):  
Surajit Chattopadhyay
Keyword(s):  
Bulk Viscosity ◽  
Modified Gravity ◽  
State Parameter ◽  
Chaplygin Gas ◽  
Scale Factor ◽  
Accelerated Expansion ◽  
Model Parameters ◽  
Modified Chaplygin Gas ◽  
Frw Universe

The present paper reports a study on the bouncing behavior of the viscous modified Chaplygin gas (MCG) in Einstein as well as modified gravity framework. For a bouncing scale factor proposed by Cai et al., Class. Quantum Grav. 28 (2011) 215011, we have studied the cosmology of MCG in presence of bulk viscosity. In Einstein gravity framework, we have studied the equation of state parameter and it has been found to cross [Formula: see text] indicating the end of the early accelerated expansion and it has also been observed that for flat FRW universe the presence of bulk viscosity induces the crossing of phantom boundary. Role of the model parameters of the MCG has also been investigated before and after the bounce. A Hubble flow dynamics has been carried out and, it was revealed that MCG is capable of realizing inflationary phase as well as an exit from inflation. A [Formula: see text] gravitational paradigm has also been considered, where the MCG density has been reconstructed in presence of bulk viscosity. Role of [Formula: see text] of the bouncing scale factor, describing how fast the bounce takes place, has also been studied in this framework.

scholarly journals A Dark Energy Model with Higher Order Derivatives of H in the f(R,T) Modified Gravity Model

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Antonio Pasqua ◽  
Surajit Chattopadhyay ◽  
Ratbay Myrzakulov
Keyword(s):  
Dark Energy ◽  
Gravity Model ◽  
Modified Gravity ◽  
Hubble Parameter ◽  
Time Derivative ◽  
Cosmic Time ◽  
Late Time ◽  
Eos Parameter ◽  
Curvature And Torsion ◽  
The Universe

We consider a model of dark energy (DE) which contains three terms (one proportional to the squared Hubble parameter, one to the first derivative, and one to the second derivative with respect to the cosmic time of the Hubble parameter) in the light of the f(R,T)=μR+νT modified gravity model, with μ and ν being two constant parameters. R and T represent the curvature and torsion scalars, respectively. We found that the Hubble parameter exhibits a decaying behavior until redshifts z≈-0.5 (when it starts to increase) and the time derivative of the Hubble parameter goes from negative to positive values for different redshifts. The equation of state (EoS) parameter of DE and the effective EoS parameter exhibit a transition from ω<-1 to ω>-1 (showing a quintom-like behavior). We also found that the model considered can attain the late-time accelerated phase of the universe. Using the statefinder parameters r and s, we derived that the studied model can attain the ΛCDM phase of the universe and can interpolate between dust and ΛCDM phase of the universe. Finally, studying the squared speed of sound vs2, we found that the considered model is classically stable in the earlier stage of the universe but classically unstable in the current stage.

Interaction of viscous modified Chaplygin gas with f(R, T) gravity

2017 ◽  
Vol 32 (28) ◽  
pp. 1750151 ◽  
Author(s):  
M. Sharif ◽  
Aisha Siddiqa
Keyword(s):  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Field Equations ◽  
Frw Universe ◽  
Eos Parameter ◽  
Total Energy Density ◽  
Conservation Of Energy ◽  
The Universe

We study the evolution of viscous modified Chaplygin gas (MCG) interacting with f(R, T) gravity in flat FRW universe, where T is the trace of energy–momentum tensor. The field equations are formulated for a particular model f(R, T) = R + 2[Formula: see text]T and constraints for the conservation of energy–momentum tensor are obtained. We investigate the behavior of total energy density, pressure and equation of state (EoS) parameter for emergent, intermediate as well as logamediate scenarios of the universe with two interacting models. It is found that the EoS parameter lies in the matter-dominated or quintessence era for all the three scenarios while the bulk viscosity enhances the expansion for the intermediate and logamediate scenarios.

Entropy-corrected new agegraphic dark energy model in the context of Chern–Simons modified gravity

2015 ◽  
Vol 24 (06) ◽  
pp. 1550044
Author(s):  
Ayman A. Aly ◽  
M. Fekry ◽  
H. Mansour
Keyword(s):  
Dark Energy ◽  
Modified Gravity ◽  
Generalized Uncertainty Principle ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Agegraphic Dark Energy ◽  
New Agegraphic Dark Energy ◽  
Energy Models ◽  
Cs Modified Gravity ◽  
Chern Simons

Within the framework of Chern–Simons (CS) modified gravity, we studied dark energy models. The new agegraphic dark energy (NADE) model, entropy-corrected new agegraphic dark energy (ECNADE) model and NADE model with generalized uncertainty principle (GUP) are investigated. For these models, we studied the evolution of scale factor a, Hubble parameter H and deceleration parameter q. On meantime, we studied the state finder parameters s and r. These models show some similar behavior with modified Chaplygin gas model in some regions, while in other regions some similarity with phantom and quintessence dark energy is noticed.

scholarly journals Dynamical system analysis of FLRW models with Modified Chaplygin gas

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ali Osman Yılmaz ◽  
Ertan Güdekli
Keyword(s):  
Dynamical System ◽  
Equation Of State ◽  
Energy Density ◽  
System Analysis ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
State Spaces ◽  
The Universe ◽  
Matter Energy ◽  
Far Future

AbstractWe investigate Friedmann–Lamaitre–Robertson–Walker (FLRW) models with modified Chaplygin gas and cosmological constant, using dynamical system methods. We assume $$p=(\gamma -1)\mu -\dfrac{A}{\mu ^\alpha }$$ p = ( γ - 1 ) μ - A μ α as equation of state where $$\mu$$ μ is the matter-energy density, p is the pressure, $$\alpha$$ α is a parameter which can take on values $$0<\alpha \le 1$$ 0 < α ≤ 1 as well as A and $$\gamma$$ γ are positive constants. We draw the state spaces and analyze the nature of the singularity at the beginning, as well as the fate of the universe in the far future. In particular, we address the question whether there is a solution which is stable for all the cases.

scholarly journals Reduced modified Chaplygin gas cosmology

2015 ◽  
Vol 2015 (2) ◽  
Author(s):  
Jianbo Lu ◽  
Danhua Geng ◽  
Lixin Xu ◽  
Yabo Wu ◽  
Molin Liu
Keyword(s):  
Chaplygin Gas ◽  
Modified Chaplygin Gas

State finder and Om diagnostics in modified and generalised Chaplygin gas from recent data

2021 ◽  
Author(s):  
P. Thakur
Keyword(s):  
Chaplygin Gas ◽  
Red Shift ◽  
Recent Past ◽  
Eos Parameter ◽  
Deceleration Phase ◽  
Om Diagnostic ◽  
Expected Values ◽  
Best Fit ◽  
The Universe ◽  
Jerk Parameter

A modified and generalised Chaplygin gas (MCG, [Formula: see text] and GCG, [Formula: see text]) has been separately chosen here as a constituent of the universe. Concept of state finder and Om diagnostics are introduced to track the dark energy in the models. Here, observed Hubble data (OHD) and binned Pantheon data of supernovae are used to determine the best-fit equation-of-state (EoS) parameters of these models and these are compared with the [Formula: see text]CDM model. The best-fit value and expected values of cosmological jerk parameter [Formula: see text], snap parameter [Formula: see text] are determined, which are close to each other. A plot of [Formula: see text] with red-shift, with themselves, as well as with deceleration parameter [Formula: see text], shows the evolution of the universe and its possible future. Variations of [Formula: see text] and EoS parameter [Formula: see text] with red-shift show acceleration–deceleration phase transition in the recent past. Lastly, the state finder pair [Formula: see text] and Om diagnostic have been utilized to discriminate the models.

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