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Scalar-tensor theories have drawn the attention of cosmologist for the past few years because they can provide mechanism to explain the observable phenomena. Moreover, the results of scalar-tensor theories can be applied in higher-order…

General Relativity and Quantum Cosmology · Physics 2020-01-17 Andronikos Paliathanasis

We study the cosmological evolution of the field equations in the context of Einstein-Aether cosmology by including a scalar field in a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker spacetime. Our analysis is separated into two…

General Relativity and Quantum Cosmology · Physics 2020-01-17 Andronikos Paliathanasis , G. Papagiannopoulos , Spyros Basilakos , John D. Barrow

In the framework of $f(T)$-gravity theory, classical and quantum cosmology has been studied in the present work for FLRW space-time model. The Noether symmetry, a point-like symmetry of the Lagrangian is used to the physical system and a…

General Relativity and Quantum Cosmology · Physics 2023-03-15 Roshni Bhaumik , Sourav Dutta , Subenoy Chakraborty

Spherically symmetric solutions for f(T) gravity models are derived by the so called Noether Symmetry Approach. First, we present a full set of Noether symmetries for some minisuperspace models. Then, we compute analytical solutions and…

General Relativity and Quantum Cosmology · Physics 2014-05-28 A. Paliathanasis , S. Basilakos , E. N. Saridakis , S. Capozziello , K. Atazadeh , F. Darabi , M. Tsamparlis

A general approach to find out exact cosmological solutions in f(R)-gravity is discussed. Instead of taking into account phenomenological models, we assume, as a physical criterium, the existence of Noether symmetries in the cosmological…

General Relativity and Quantum Cosmology · Physics 2010-02-10 Salvatore Capozziello , Antonio De Felice

Canonization of F(R) theory of gravity to explore Noether symmetry is performed treating R - 6(\frac{\ddot a}{a} + \frac{\dot a^2}{a^2} + \frac{k}{a^2}) = 0 as a constraint of the theory in Robertson-Walker space-time, which implies that R…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-26 Kaushik Sarkar , Nayem Sk. , Subhra Debnath , Abhik Kumar Sanyal

Teleparallel Horndeski theory offers an avenue through which to circumvent the speed constraint of gravitational waves in an efficient manner. However, this provides an even larger plethora of models due to the increase in action terms. In…

General Relativity and Quantum Cosmology · Physics 2022-03-30 Konstantinos F. Dialektopoulos , Jackson Levi Said , Zinovia Oikonomopoulou

We derive the Lie and the Noether conditions for the equations of motion of a dynamical system in a $n-$dimensional Riemannian space. We solve these conditions in the sense that we express the symmetry generating vectors in terms of the…

Mathematical Physics · Physics 2015-06-12 Michael Tsamparlis

We study in which conditions the Hyperextended Scalar Tensor theory in an FLRW background admits a Noether symmetry and derive the vectors field generating it.

General Relativity and Quantum Cosmology · Physics 2009-11-10 Stephane Fay

The exact solutions of spherically symmetric space-times are explored by using Noether symmetries in $f(R,\phi,X)$ gravity with $R$ the scalar curvature, $\phi$ a scalar field and $X$ the kinetic term of $\phi$. Some of these solutions can…

General Relativity and Quantum Cosmology · Physics 2019-02-20 Sebastian Bahamonde , Kazuharu Bamba , Ugur Camci

Investigations of the dynamic modes of the Poincare gauge theory of gravity found only two good propagating torsion modes; they are effectively a scalar and a pseudoscalar. Cosmology affords a natural situation where one might see…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Kun-Feng Shie , James M. Nester , Hwei-Jang Yo

In this paper, we have presented the Noether symmetries of flat FRW spacetime in the context of a new action in Teleparallel Gravity which we construct it based on $f(R)$ version. This modified action contains a coupling between scalar…

General Relativity and Quantum Cosmology · Physics 2017-04-26 Behzad Tajahmad

This paper is devoted to the study of Noether gauge symmetries of $f(T)$ gravity minimally coupled with a canonical scalar field. We explicitly determine the unknown functions of the theory $f(T),V(\phi), W(\phi)$. We have shown that there…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-13 Adnan Aslam , Mubasher Jamil , Davood Momeni , Ratbay Myrzakulov

We show how the scalar field, a candidate of quintessence, in a proposed model of the scalar-tensor theories of gravity provides a way to understand a small but nonzero cosmological constant as indicated by recent observations. A particular…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Yasunori Fujii

In $F(T)$ gravity theory, a Friedman-Robertson-Walker cosmological model with $f$-essence where fermion field is non-minimally coupled with the gravitational field is studied. Using the Noether symmetry approach the possible forms of $F(T)$…

General Physics · Physics 2016-01-28 Kairat Myrzakulov , Pyotr Tsyba , Ratbay Myrzakulov

The Noether symmetry analysis is applied for the analysis of the field equations in an anisotropic background in $f(T,B)$-theory. We consider the $f\left( T,B\right) =T+F\left( B\right) $ which describes a small deviation from TEGR…

General Relativity and Quantum Cosmology · Physics 2022-07-19 Andronikos Paliathanasis

We consider scalar tensor theories of gravity assuming that the scalar field is non minimally coupled with gravity. We use this theory to study evolution of a flat homogeneous and isotropic universe. In this case the dynamical equations can…

Astrophysics · Physics 2012-07-13 M. Demianski , E. Piedipalumbo , C. Rubano , C. Tortora

We present the gravitational coupling function $\omega(\phi)$ in the vacuum scalar-tensor theory as allowed by the Noether symmetry. We also obtain some exact cosmological solutions in the spatially homogeneous and isotropic background…

General Relativity and Quantum Cosmology · Physics 2015-06-25 B. Modak , S. Kamilya , S. Biswas

In this work, we examine solutions of the system of equations obtained by applying the Noether gauge symmetry (NGS) and its conserved quantity for the standard general relativity (GR) and the non-minimal derivative coupling (NMDC)…

General Relativity and Quantum Cosmology · Physics 2022-06-27 Muhammadsorfee Dolohtahe , Watcharakorn Srikom , Phongpichit Channuie , Narakorn Kaewkhao

We consider a cosmological model with two scalar fields minimally coupled to gravity which have a mixed kinetic term. Hence, Chiral cosmology is included in our analysis. The coupling function and the potential function, which depend on one…

General Relativity and Quantum Cosmology · Physics 2019-09-04 N. Dimakis , A. Paliathanasis , Petros A. Terzis , T. Christodoulakis