scholarly journals Scalar–tensor teleparallel gravity with boundary term by Noether symmetries

2018 ◽  
Vol 15 (09) ◽  
pp. 1850151 ◽  
Author(s):  
G. Gecim ◽  
Y. Kucukakca
Keyword(s):  
Scalar Field ◽  
Teleparallel Gravity ◽  
Boundary Term ◽  
Noether Symmetry ◽  
Late Time ◽  
Field Equations ◽  
Symmetry Approach ◽  
Tensor Theory ◽  
Accelerating Expansion ◽  
Frw Cosmological Model

In the framework of teleparallel gravity, the Friedman–Robertson–Walker (FRW) cosmological model with scalar tensor theory, where scalar field is non-minimally coupled to both the torsion scalar and boundary term, is studied. Utilizing the Noether symmetry approach in such a theory, we obtain the explicit forms of the couplings and potential as a function of the scalar field. We present some important cosmological solutions for the modified field equations using these functions gotten via the Noether symmetry approach. Finally, the interesting cosmological properties of these solutions are discussed in detail, and it is shown that they can describe a universe leading to the late-time accelerating expansion.

scholarly journals Cosmological Solutions for the Geometrical Scalar-Tensor with the Potential Determined by the Noether Symmetry Approach

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1110
Author(s):  
Adriano B. Barreto ◽  
Gilberto M. Kremer
Keyword(s):  
Scalar Field ◽  
Scalar Potential ◽  
Noether Symmetry ◽  
Jordan Frame ◽  
Scalar Tensor Theory ◽  
Symmetry Approach ◽  
Tensor Theory ◽  
Dark Energy Component ◽  
Frw Cosmological Model

The aim of this work is to study a scalar-tensor theory where owing to Palatini’s variational method the space-time is endowed with a geometrical structure of Weyl integrable type. The geometrical nature of the scalar field is related to the non-metricity so that the theory is known as geometrical scalar-tensor. On the framework of Weyl transformations, a non-minimally coupled scalar-tensor theory on the Jordan frame corresponds to a minimally coupled Einstein–Hilbert action on the Einstein frame. The scalar potential is selected by the Noether symmetry approach in order to obtain conserved quantities for the FRW cosmological model. Exact solutions are obtained and analyzed in the context of the cosmological scenarios consistent with an expanding universe. A particular case is matched in each frame and the role of scalar field as a dark energy component is discussed.

Can Noether symmetry in modified f(G) gravity always yield cosmic evolution?

2017 ◽  
Vol 32 (11) ◽  
pp. 1750046
Author(s):  
Malay Krishna Dutta ◽  
B. Modak
Keyword(s):  
Ideal Fluid ◽  
Functional Form ◽  
Noether Symmetry ◽  
Late Time ◽  
Field Equations ◽  
Symmetry Approach ◽  
Cosmic Evolution ◽  
Accelerating Expansion ◽  
Modified Theory Of Gravity ◽  
Modified Theory

We discuss Noether symmetry approach in the modified theory of gravity with Gauss–Bonnet (GB) interaction-f(G) including an ideal fluid in Friedmann–Lemaître–Robertson–Walker (FLRW) background. It yields functional form of f(G) from the symmetry. The existence of Noether symmetry gives the scale factor in two cases, but these are not satisfied by field equations in general. In another case, the solution of field equations shows late-time transition to an accelerating expansion when matter is dust, however the solution including dust and radiation is always in accelerating era.

Brans–Dicke type teleparallel scalar–tensor theory

2017 ◽  
Vol 32 (34) ◽  
pp. 1750183 ◽  
Author(s):  
Mustafa Salti ◽  
Oktay Aydogdu ◽  
Hilmi Yanar ◽  
Figen Binbay
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Scalar Field ◽  
Noether Symmetry ◽  
Scalar Tensor Theory ◽  
Minimal Coupling ◽  
Energy Effect ◽  
New Model ◽  
Symmetry Approach ◽  
Tensor Theory

The teleparallel alternative of general relativity which is based on torsion instead of curvature is considered as the gravitational sector to explore the dark universe. Inspired from the well-known Brans–Dicke gravity, here, we introduce a new proposal for the galactic dark energy effect. The new model includes a scalar field with self-interacting potential and a non-minimal coupling between the gravity and scalar field. Additionally, we analyze the idea via the Noether symmetry approach and thermodynamics.

scholarly journals Dirac Field as a Source of the Inflation in2+1Dimensional Teleparallel Gravity

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Ganim Gecim ◽  
Yusuf Sucu
Keyword(s):  
Early Time ◽  
Teleparallel Gravity ◽  
Noether Symmetry ◽  
Dirac Field ◽  
Late Time ◽  
Late Time Acceleration ◽  
Symmetry Approach ◽  
Gauge Term ◽  
Acceleration Of The Universe ◽  
The Universe

In this paper, we study early-time inflation and late-time acceleration of the universe by nonminimally coupling the Dirac field with torsion in the spatially flat Friedman-Robertson-Walker (FRW) cosmological model background. The results obtained by the Noether symmetry approach with and without a gauge term are compared. Additionally, we compare these results with that of the3+1dimensional teleparallel gravity under Noether symmetry approach. And we see that the study explains early-time inflation and late-time acceleration of the universe.

scholarly journals Noether symmetry approach in f (T, B) teleparallel gravity with a fermionic field

2021 ◽  
Vol 2090 (1) ◽  
pp. 012058
Author(s):  
Yerlan Myrzakulov ◽  
Sabit Bekov ◽  
Kairat Myrzakulov
Keyword(s):  
Cosmological Model ◽  
Teleparallel Gravity ◽  
Noether Symmetry ◽  
Accelerated Expansion ◽  
Late Time ◽  
Fermionic Field ◽  
Symmetry Approach ◽  
Expansion Of The Universe ◽  
Isotropic Cosmological Model ◽  
The Universe

Abstract In this work, we consider a homogeneous and isotropic cosmological model of the universe in f (T, B) gravity with non-minimally coupled fermionic field. In order to find the form of the coupling function F(Ψ), the potential function V (Ψ) of the fermionic field and the function f (T, B), we found through the Noether symmetry approach. The results obtain are coincide with the observational data that describe the late-time accelerated expansion of the universe.

scholarly journals EXACT SOLUTIONS FOR COSMOLOGICAL MODELS WITH A SCALAR FIELD

2002 ◽  
Vol 17 (03) ◽  
pp. 375-381 ◽  
Author(s):  
H. MOTAVALI ◽  
M. GOLSHANI
Keyword(s):  
Scalar Field ◽  
Exact Solutions ◽  
Cosmological Models ◽  
Coupling Function ◽  
Noether Symmetry ◽  
Scalar Tensor Theory ◽  
Frw Cosmology ◽  
Field Equations ◽  
Tensor Theory ◽  
Cosmological Solutions

We consider the existence of a Noether symmetry in the scalar–tensor theory of gravity in flat Friedman–Robertson–Walker (FRW) cosmology. The forms of coupling function ω(ϕ) and generic potential V(ϕ) are obtained by requiring the existence of a Noether symmetry for such theory. We derive exact cosmological solutions of the field equations from a point-like Lagrangian.

scholarly journals Anisotropic solution in phantom cosmology via Noether symmetry approach

2018 ◽  
Vol 96 (7) ◽  
pp. 677-680 ◽  
Author(s):  
I. Basaran Oz ◽  
Y. Kucukakca ◽  
N. Unal
Keyword(s):  
Scalar Field ◽  
Bianchi Type ◽  
Space Time ◽  
Noether Symmetry ◽  
Type I ◽  
Field Equations ◽  
Anisotropic Solution ◽  
Bianchi Type I ◽  
Symmetry Approach ◽  
The Universe

In this study, we consider a phantom cosmology in which a scalar field is minimally coupled to gravity. For anisotropic locally rotational symmetric (LRS) Bianchi type I space–time, we use the Noether symmetry approach to determine the potential of such a theory. It is shown that the potential must be in the trigonometric form as a function of the scalar field. We solved the field equations of the theory using the result obtained from the Noether symmetry. Our solution shows that the universe has an accelerating expanding phase.

scholarly journals Noether symmetries of Einstein-aether scalar field cosmology

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Yusuf Kucukakca ◽  
Amin Rezaei Akbarieh
Keyword(s):  
Scalar Field ◽  
Noether Symmetry ◽  
Accelerated Expansion ◽  
Noether Symmetries ◽  
Field Equations ◽  
Symmetry Approach ◽  
Expansion Of The Universe ◽  
Frw Metric ◽  
Scalar Field Cosmology ◽  
The Universe

AbstractIn this paper, we explore an Einstein-aether cosmological model by adding the scalar field in which it has an interaction with the aether field. For the cosmological implications of the model, we consider that the universe can be described by the spatially flat FRW metric together with the matter dominated universe. Applying Noether symmetry approach to the point-like Lagrangian we determine the explicit forms of unknown functions i.e. the potential and coupling function. We solve the analytical cosmological solutions of the field equations admitting the Noether symmetry, basically divided into two parts. Our results show that the obtained solutions lead to an accelerated expansion of the universe. We also discuss the tensor perturbations within the framework of this model in order to get information about the mass of gravitational waves.

scholarly journals Teleparallel gravity with non-minimally coupled f-essence via Noether symmetry approach

2021 ◽  
Vol 1730 (1) ◽  
pp. 012022
Author(s):  
Kairat Myrzakulov ◽  
Duman Kenzhalin ◽  
Nurgissa Myrzakulov
Keyword(s):  
Teleparallel Gravity ◽  
Noether Symmetry ◽  
Symmetry Approach

FRW cosmological models with cosmological constant in f (R,T) theory of gravity

2021 ◽  
Author(s):  
Anirudh Pradhan ◽  
Priyanka Garg ◽  
Archana Dixit
Keyword(s):  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Apparent Magnitude ◽  
Physical Parameters ◽  
Distance Modulus ◽  
Luminosity Distance ◽  
Field Equations ◽  
Eos Parameter ◽  
Accelerating Expansion ◽  
Frw Cosmological Model

In the present paper, we have generalized the behaviors of {\color{blue}transit-decelerating to accelerating} FRW cosmological model in f (R, T) gravity theory, where R, T are Ricci scalar and trace of energy-momentum tensor respectively. The solution of the corresponding field equations is obtained by assuming a linear function of the Hubble parameter H, i.e., q = c<sub>1</sub> + c<sub>2</sub>H which gives a time-dependent DP (deceleration parameter) q(t)=-1+\frac{c_2}{\sqrt{2c_2 t +c_3}}, where c<sub>3</sub> and c<sub>2</sub> are arbitrary integrating constants [Tiwari et al., Eur. Phys. J. Plus: 131, 447 (2016); 132, 126 (2017)]. There are two scenarios in which we explain the particular form of scale factor thus obtained  (i) By using the recent constraints from OHD and JLA data which shows a cosmic deceleration to acceleration and (ii) By using new constraints from supernovae type la union data which shows accelerating expansion universe (q<0) throughout the evolution. We have observed that the EoS parameter, energy density parameters, and important cosmological planes yield the results compatible with the modern observational data. For the derived models, we have calculated various physical parameters as Luminosity distance, Distance modulus, and Apparent magnitude versus redshift for both supporting current observations.

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