scholarly journals Couplingq-Deformed Dark Energy to Dark Matter

2016 ◽  
Vol 2016 ◽  
pp. 1-20 ◽  
Author(s):  
Emre Dil
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Phase Space ◽  
Scalar Field ◽  
Dark Energy Model ◽  
Cosmological Parameters ◽  
Energy Model ◽  
Late Time ◽  
Acceleration Phase ◽  
Energy Models

We propose a novel coupled dark energy model which is assumed to occur as aq-deformed scalar field and investigate whether it will provide an expanding universe phase. We consider theq-deformed dark energy as coupled to dark matter inhomogeneities. We perform the phase-space analysis of the model by numerical methods and find the late-time accelerated attractor solutions. The attractor solutions imply that the coupledq-deformed dark energy model is consistent with the conventional dark energy models satisfying an acceleration phase of universe. At the end, we compare the cosmological parameters of deformed and standard dark energy models and interpret the implications.

scholarly journals Dynamical system analysis of dark energy models in scalar coupled Metric-Torsion theories

2017 ◽  
Vol 26 (13) ◽  
pp. 1750149 ◽  
Author(s):  
Arshdeep Singh Bhatia ◽  
Sourav Sur
Keyword(s):  
Dark Energy ◽  
Phase Space ◽  
Scalar Field ◽  
System Analysis ◽  
Coupling Parameter ◽  
Cosmological Parameters ◽  
Direct Interaction ◽  
Cosmic Acceleration ◽  
Energy Models ◽  
Space Dynamics

We study the phase-space dynamics of cosmological models in the theoretical formulations of nonminimal metric-torsion couplings with a scalar field, and investigate in particular the critical points (CPs) which yield stable solutions exhibiting cosmic acceleration driven by the dark energy (DE). The latter is so defined that it effectively has no direct interaction with the cosmological fluid, although in an equivalent scalar–tensor cosmological setup, the scalar field interacts with the fluid (which we consider to be the pressureless dust). Determining the conditions for the existence of the stable CPs, we check their physical viability in both Einstein and Jordan frames. We also verify that in either of these frames, the evolution of the universe at the corresponding stable points matches with that given by the respective exact solutions we have found in an earlier work [S. Sur and A. S. Bhatia, arXiv:1611.00654 [gr-qc]]. We not only examine the regions of physical relevance in the phase-space when the coupling parameter is varied, but also demonstrate the evolution profiles of the cosmological parameters of interest along fiducial trajectories in the effectively noninteracting scenarios, in both Einstein and Jordan frames.

scholarly journals Dynamics of nonlinear interacting dark energy models

2019 ◽  
Vol 28 (12) ◽  
pp. 1950161 ◽  
Author(s):  
Andronikos Paliathanasis ◽  
Supriya Pan ◽  
Weiqiang Yang
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Critical Points ◽  
Cosmological Parameters ◽  
Late Time ◽  
Interacting Dark Energy ◽  
Energy Models ◽  
Flrw Universe ◽  
The Stability ◽  
Interacting Dark Energy Models

We investigate the cosmological dynamics of interacting dark energy models in which the interaction function is nonlinear in terms of the energy densities. Considering explicitly the interaction between a pressureless dark matter and a scalar field, minimally coupled to Einstein gravity, we explore the dynamics of the spatially flat FLRW universe for the exponential potential of the scalar field. We perform the stability analysis for three nonlinear interaction models of our consideration through the analysis of critical points and we investigate the cosmological parameters and discuss the physical behavior at the critical points. From the analysis of the critical points we find a number of possibilities that include the stable late-time accelerated solution, [Formula: see text]CDM-like solution, radiation-like solution and moreover the unstable inflationary solution.

scholarly journals Dynamics of Generalized Tachyon Field in Teleparallel Gravity

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Behnaz Fazlpour ◽  
Ali Banijamali
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Dark Energy Model ◽  
Teleparallel Gravity ◽  
Energy Model ◽  
Tachyon Field ◽  
Coincidence Problem

We study dynamics of generalized tachyon scalar field in the framework of teleparallel gravity. This model is an extension of tachyonic teleparallel dark energy model which has been proposed by Banijamali and Fazlpour (2012). In contrast with tachyonic teleparallel dark energy model that has no scaling attractors, here we find some scaling attractors which means that the cosmological coincidence problem can be alleviated. Scaling attractors are presented for both interacting and noninteracting dark energy and dark matter cases.

Interacting ω(q) dark energy model with phase space analysis

2021 ◽  
Vol 36 (31) ◽  
Author(s):  
Koblandy Yerzhanov ◽  
Shynaray Myrzakul ◽  
Duman Kenzhalin ◽  
Martiros Khurshudyan
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Phase Space ◽  
Deceleration Parameter ◽  
Dark Energy Model ◽  
Cold Dark Matter ◽  
Forthcoming Paper ◽  
Energy Model ◽  
Phase Space Analysis ◽  
Space Analysis

The phase space analysis has been used to probe the accelerated expansion of the Universe when [Formula: see text] dark energy interacts with cold dark matter. Non-gravitational interactions [Formula: see text] and [Formula: see text] considered in this work are one of the first models of sign changing interactions that appeared in the literature. Specific [Formula: see text] dark energy model with [Formula: see text] has been assumed and all late time scaling attractors have been found. This is a two-parameter model with [Formula: see text] and [Formula: see text] parameters to be determined, while [Formula: see text] is the deceleration parameter. In general the motivation to consider similar fluid models is directly related to the attempts to unify dark energy and dark matter involving the properties of the deceleration parameter. The previous study using similar dark energy model showed that the BOSS result for the expansion rate at [Formula: see text] can be explained without interaction with cold dark matter. In this way, the previous result provides a reasonable basis to organize future studies in this direction. This study is one of the first attempts in this direction. It should be mentioned that the full comparison of the models with observation data and the classification of future singularities have been left as a subject of a forthcoming paper. There are several ways that the model can be extended which also has been left as a subject of a forthcoming paper.

Interacting new holographic dark energy model with varying G in nonflat universe

2013 ◽  
Vol 91 (12) ◽  
pp. 1090-1092
Author(s):  
V. Fayaz ◽  
F. Felegary ◽  
H. Hossienkhani
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Dark Energy Model ◽  
Holographic Dark Energy ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Late Time ◽  
Holographic Dark Energy Model ◽  
Expansion Of The Universe ◽  
The Universe

Motivated by the work of Karami and Fehri (Phys. Lett. B, 684, 61 (2010)). We generalize their work with varying G. We investigate the new holographic dark energy model with varying G. We consider a spatially nonflat universe containing interacting new holographic dark energy with pressureless dark matter. We obtain the equation of state and the deceleration parameters. Also we reconstruct ωA for a = a0tn and H = [β/(α − 1)](1/t) in the late time universe. We also obtain q for a = a0tn and H = [β/(α − 1)](1/t) in the present time universe, which describes accelerated expansion of the universe.

scholarly journals Cosmological Implications of the Generalized Entropy Based Holographic Dark Energy Models in Dynamical Chern-Simons Modified Gravity

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
M. Younas ◽  
Abdul Jawad ◽  
Saba Qummer ◽  
H. Moradpour ◽  
Shamaila Rani
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Modified Gravity ◽  
Dark Energy Model ◽  
State Parameter ◽  
Energy Model ◽  
Evolutionary Equation ◽  
Energy Models ◽  
Equation Of State Parameter ◽  
Chern Simons

Recently, Tsallis, Rényi, and Sharma-Mittal entropies have widely been used to study the gravitational and cosmological setups. We consider a flat FRW universe with linear interaction between dark energy and dark matter. We discuss the dark energy models using Tsallis, Rényi, and Sharma-Mittal entropies in the framework of Chern-Simons modified gravity. We explore various cosmological parameters (equation of state parameter, squared sound of speed ) and cosmological plane (ωd-ωd′, where ωd′ is the evolutionary equation of state parameter). It is observed that the equation of state parameter gives quintessence-like nature of the universe in most of the cases. Also, the squared speed of sound shows stability of Tsallis and Rényi dark energy model but unstable behavior for Sharma-Mittal dark energy model. The ωd-ωd′ plane represents the thawing region for all dark energy models.

scholarly journals Addressing the high-f problem in pseudo-Nambu–Goldstone boson dark energy models with dark matter–dark energy interaction

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Upala Mukhopadhyay ◽  
Avik Paul ◽  
Debasish Majumdar
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Dark Energy Model ◽  
Goldstone Boson ◽  
The Other ◽  
Mass Limit ◽  
Energy Models ◽  
Energy Interaction ◽  
Energy Scenario ◽  
Type Potential

AbstractWe consider a dark energy scenario driven by a scalar field $$\phi $$ ϕ with a pseudo-Nambu–Goldstone boson (pNGB) type potential $$V(\phi )=\mu ^4 \left( 1+ \mathrm{cos}(\phi /f) \right) $$ V ( ϕ ) = μ 4 1 + cos ( ϕ / f ) . The pNGB originates out of breaking of spontaneous symmetry at a scale f close to Planck mass $$M_\mathrm{{pl}}$$ M pl . We consider two cases namely the quintessence dark energy model with pNGB potential and the other, where the standard pNGB action is modified by the terms related to Slotheon cosmology. We demonstrate that for this pNGB potential, high-f problem is better addressed when the interaction between dark matter and dark energy is taken into account and that Slotheon dark energy scenario works even better over quintessence in this respect. To this end, a mass limit for dark matter is also estimated.

scholarly journals Tsallis agegraphic dark energy model

2019 ◽  
Vol 34 (11) ◽  
pp. 1950086 ◽  
Author(s):  
M. Abdollahi Zadeh ◽  
A. Sheykhi ◽  
H. Moradpour
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Dark Energy Model ◽  
Late Time ◽  
Conformal Time ◽  
Classical Level ◽  
Agegraphic Dark Energy ◽  
Energy Models ◽  
Age Of The Universe ◽  
The Universe

Using the non-extensive Tsallis entropy and the holographic hypothesis, we propose a new dark energy (DE) model with timescale as infrared (IR) cutoff. Considering the age of the Universe as well as the conformal time as IR cutoffs, we investigate the cosmological consequences of the proposed DE models and study the evolution of the Universe filled by a pressureless matter and the obtained DE candidates. We find that although this model can describe the late time acceleration and the density, deceleration and the equation of state parameters show satisfactory behavior by themselves, these models are classically unstable unless the interaction between the two dark sectors of the Universe is taken into account. In addition, the results of the existence of a mutual interaction between the cosmos sectors are also addressed. We find out that the interacting models are stable at the classical level which is in contrast to the original interacting agegraphic dark energy models which are classically unstable [K. Y. Kim, H. W. Lee and Y. S. Myung, Phys. Lett. B 660, 118 (2008)].

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