scholarly journals Qualitative study of anisotropic cosmological models with dark sector coupling

2017 ◽  
Vol 95 (11) ◽  
pp. 1049-1061 ◽  
Author(s):  
Rakesh Raushan ◽  
R. Chaubey
Keyword(s):  
Dark Energy ◽  
Phase Plane ◽  
Bianchi Type ◽  
Dynamical Evolution ◽  
Phase Plane Analysis ◽  
Type I ◽  
Dark Sector ◽  
Linear Coupling ◽  
Plane Analysis ◽  
Rotationally Symmetric

In this paper, we study the dynamical evolution of locally rotationally symmetric (LRS) Bianchi type I cosmological model with coupling of dark sector. We investigate the phase-plane analysis when dark energy is modelled as exponential quintessence, and is coupled to dark energy matter via linear coupling between both dark components. The evolution of cosmological solutions is studied by using dynamical systems techniques. Stability and viability issues for three different physically viable linear couplings between both dark components are presented and discussed in detail.

Dynamical analysis of anisotropic cosmological model with quadratic dark sector coupling

2019 ◽  
Vol 16 (02) ◽  
pp. 1950023 ◽  
Author(s):  
Rakesh Raushan ◽  
R. Chaubey
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
Dynamical Evolution ◽  
Dynamical Analysis ◽  
Phase Plane Analysis ◽  
Late Time ◽  
Type I ◽  
Dark Sector ◽  
Scaling Solution ◽  
Coupling Parameters

The present work deals with the dynamical evolution of LRS Bianchi type I (LRS BI) cosmological model with quadratic dark sector coupling. We investigate the phase-plane analysis of LRS BI model with dark energy, when dark energy is modeled as exponential quintessence, and is coupled to dark matter via energy exchange. The evolution of cosmological solutions are studied by using dynamical systems method. Stability and viability of the models are discussed for four different choices of quadratic dark sector coupling parameters. In each model, we have obtained a late-time accelerating fixed point (future attractor), which is not a scaling solution.

scholarly journals LOCALLY ROTATIONALLY SYMMETRIC BIANCHI TYPE-I COSMOLOGICAL MODEL IN f(T) GRAVITY: FROM EARLY TO DARK ENERGY DOMINATED UNIVERSE

2014 ◽  
Vol 23 (01) ◽  
pp. 1450004 ◽  
Author(s):  
M. E. RODRIGUES ◽  
I. G. SALAKO ◽  
M. J. S. HOUNDJO ◽  
J. TOSSA
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
Dark Energy Model ◽  
Bianchi Type ◽  
Rotational Symmetry ◽  
Type I ◽  
Bianchi Type I ◽  
Reconstruction Scheme ◽  
Rotationally Symmetric ◽  
The Universe

We study the locally rotational symmetry Bianchi type-I dark energy model in the framework of f(T) theory of gravity, where T denotes the torsion scalar. A viable cosmological model is undertaken and the isotropization of this latter is checked, yielding a result that reflects the real evolution of our universe. Moreover, still in the anisotropic optic, a more complicated f(T) model is obtained from the cosmological reconstruction scheme and the analysis shows that the universe is more anisotropic at the beginning if the terms of higher order in T are not considered. This means that the nonlinear model should be favored by observational data.

Infinitely Many Rotationally Symmetric Solutions to a Class of Semilinear Laplace–Beltrami Equations on Spheres

2015 ◽  
Vol 58 (4) ◽  
pp. 723-729 ◽  
Author(s):  
Alfonso Castro ◽  
Emily M. Fischer
Keyword(s):  
Differential Equation ◽  
Phase Plane ◽  
Phase Plane Analysis ◽  
Point Boundary ◽  
Initial Value ◽  
Beltrami Equations ◽  
Plane Analysis ◽  
Singular Ordinary Differential Equation ◽  
Rotationally Symmetric ◽  
Pohozaev Type Identity

AbstractWe show that a class of semilinear Laplace–Beltrami equations on the unit sphere in ℝn has inûnitely many rotationally symmetric solutions. The solutions to these equations are the solutions to a two point boundary value problem for a singular ordinary differential equation. We prove the existence of such solutions using energy and phase plane analysis. We derive a Pohozaev-type identity in order to prove that the energy to an associated initial value problem tends to infinity as the energy at the singularity tends to infinity. The nonlinearity is allowed to grow as fast as |s|p-1s for |s| large with 1 < p < (n + 5)/(n − 3).

scholarly journals DARK ENERGY MODELS AND LAWS OF THERMODYNAMICS IN BIANCHI I MODEL

2012 ◽  
Vol 27 (33) ◽  
pp. 1250187 ◽  
Author(s):  
M. SHARIF ◽  
RABIA SALEEM
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Apparent Horizon ◽  
Second Law Of Thermodynamics ◽  
Type I ◽  
Generalized Second Law ◽  
Energy Models ◽  
Rotationally Symmetric ◽  
Laws Of Thermodynamics ◽  
Fixed Radius

This paper is devoted to check validity of the laws of thermodynamics for locally rotationally symmetric (LRS) Bianchi type I (BI) universe model which is filled with combination of dark matter and dark energy (DE). We take two types of DE models, i.e. generalized holographic DE (HDE) and generalized Ricci DE (RDE). It is proved that the first and generalized second law of thermodynamics (GSLT) are valid on the apparent horizon for both the models. Further, we take fixed radius L of the apparent horizon with original holographic or RDE. We conclude that the first and GSLT do not hold on the horizon of fixed radius L for both the models.

scholarly journals Mixed fluid cosmological model in f(R, T) gravity

2020 ◽  
Vol 98 (11) ◽  
pp. 1015-1022 ◽  
Author(s):  
Parbati Sahoo ◽  
Barkha Taori ◽  
K.L. Mahanta
Keyword(s):  
Cosmological Model ◽  
Bianchi Type ◽  
Type I ◽  
Time Varying ◽  
Eos Parameter ◽  
Barotropic Fluid ◽  
Rotationally Symmetric ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Mixed Fluid

We construct a locally rotationally symmetric (LRS) Bianchi type-I cosmological model in f(R, T) theory of gravity when the source of gravitation is a mixture of barotropic fluid and dark energy (DE) by employing a time-varying deceleration parameter. We observe through the behavior of the state finder parameters (r, s) that our model begins from the Einstein static era and goes to ΛCDM era. The equation of state (EOS) parameter (ωd) for DE varies from the phantom (ω < –1) phase to quintessence (ω > –1) phase, which is consistent with observational results. It is found that the discussed model can reproduce the current accelerating phase of the expansion of the universe.

Whole-body phase plane analysis for standard maximum vertical jump assessment

2021 ◽  
Vol 90 ◽  
pp. 203-204
Author(s):  
C. Rodrigues ◽  
M. Correia ◽  
J. Abrantes ◽  
B. Rodrigues ◽  
J. Nadal
Keyword(s):  
Phase Plane ◽  
Vertical Jump ◽  
Whole Body ◽  
Phase Plane Analysis ◽  
Plane Analysis

Constraints on the Ricci dark energy cosmologies in Bianchi type I model

2021 ◽  
pp. 2150095
Author(s):  
H. Hossienkhani ◽  
N. Azimi ◽  
H. Yousefi
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Bianchi Type ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Likelihood Method ◽  
Type I ◽  
Ricci Dark Energy ◽  
Bianchi Type I ◽  
The Impact

The impact of anisotropy on the Ricci dark energy cosmologies is investigated where it is assumed that the geometry of the universe is described by Bianchi type I (BI) metric. The main goal is to determine the astrophysical constraints on the model by using the current available data as type Ia supernovae (SNIa), the Baryon Acoustic Oscillation (BAO), and the Hubble parameter [Formula: see text] data. In this regard, a maximum likelihood method is applied to constrain the cosmological parameters. Combining the data, it is found out that the allowed range for the density parameter of the model stands in [Formula: see text]. With the help of the Supernova Legacy Survey (SNLS) sample, we estimate the possible dipole anisotropy of the Ricci dark energy model. Then, by using a standard [Formula: see text] minimization method, it is realized that the transition epoch from early decelerated to current accelerated expansion occurs faster in Ricci dark energy model than [Formula: see text]CDM model. The results indicate that the BI model for the Ricci dark energy is consistent with the observational data.

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