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We reconcile seemingly conflicting statements in the literature about the behavior of cosmological solutions in modified theories of gravity where the Einstein-Hilbert Lagrangian for gravity is modified by the addition of a function of the…

Astrophysics · Physics 2008-11-26 Ignacy Sawicki , Wayne Hu

We review a system of autonomous differential equations developed in our previous work [1] describing a flat cosmology filled with a barotropic fluid and a scalar field with a modified kinetic term of the form L=F(X)-V(phi). We analyze the…

General Relativity and Quantum Cosmology · Physics 2014-04-04 Josue De-Santiago , Jorge L. Cervantes-Cota

We present the case of time-varying cosmological term $\Lambda(t)$. The main idea arises by proposing that as in the cosmological constant case, the scalar potential is identified as $ V(\phi)=2\Lambda$, with $\Lambda$ a constant, this…

General Physics · Physics 2019-11-21 J. Socorro , M. D'oleire , Luis O. Pimentel

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

In this Letter by utilizing the Noether symmetry approach in cosmology, we attempt to find the tachyon potential via the application of this kind of symmetry to a flat Friedmann-Robertson-Walker (FRW) metric. We reduce the system of…

General Physics · Physics 2011-09-01 Mubasher Jamil , F. M. Mahomed , D. Momeni

In the framework of phantom quintessence cosmology, we use the Noether Symmetry Approach to obtain general exact solutions for the cosmological equations. This result is achieved by the quintessential (phantom) potential determined by the…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-30 S. Capozziello , E. Piedipalumbo , C. Rubano , P. Scudellaro

We consider the cosmology derived from $f(T,B)$ gravity where $T$ is the torsion scalar and $B=\frac{2}{e}\partial_{\mu}(e T^{\mu})$ a boundary term. In particular we discuss how it is possible to recover, under the same standard, the…

General Relativity and Quantum Cosmology · Physics 2017-03-08 Sebastian Bahamonde , Salvatore Capozziello

We analyze the cosmology of a general Scalar-Tensor theory which encompasses generalized Brans-Dicke theory, Gauss-Bonnet gravity, non-minimal derivative gravity, generalized Galileon gravity and also the general k-essence type models.…

General Relativity and Quantum Cosmology · Physics 2017-03-07 Erfan Masaeli , Meysam Motaharfar , Hamid Reza Sepangi

We show that the simplest FLRW cosmological system consisting in the homogeneous and isotropic massless Einstein-Scalar system enjoys a hidden conformal symmetry under the 1D conformal group $SL(2,\mathbb{R})$ acting as Mobius…

General Relativity and Quantum Cosmology · Physics 2025-02-06 Jibril Ben Achour , Etera R. Livine

A modified form of non-locally corrected theory of gravity is investigated in the context of cosmology and the Newtonian limit. This form of non-local correction to classic Einstein-Hilbert action can be locally represented by a…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Dao-Jun Liu , Bin Yang , Xing-Hua Jin

In this paper, we investigate the dynamics of the universe on the background of f-essence when a non-minimal coupling with gravity. Field equations are obtained and using the Noether theorem, explicit forms of the coupling function and the…

General Physics · Physics 2017-05-26 Tolkynay Myrzakul , Ertan Gudekli , Shynaray Myrzakul , Ratbay Myrzakulov

A new set of field equations for a space-time dependent Newton's constant $G(x)$ and cosmological constant $\Lambda(x)$ in the presence of matter is presented. We prove that it represents the most general mathematically consistent,…

General Relativity and Quantum Cosmology · Physics 2021-05-19 Alfio Bonanno , Georgios Kofinas , Vasilios Zarikas

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 study the cosmology of a covariant scalar field respecting a Galilean symmetry in flat space-time. We show the existence of a tracker solution that finally approaches a de Sitter fixed point responsible for cosmic acceleration today. The…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 Antonio De Felice , Shinji Tsujikawa

In this work, we take a short recap of a formal framework of the Eddington-inspired Born-Infeld (EiBI) theory of gravity and derive the point-like Lagrangian for underlying theory based on the use of Noether gauge symmetries (NGS). We study…

General Relativity and Quantum Cosmology · Physics 2021-04-27 Thanyagamon Kanesom , Phongpichit Channuie , Narakorn Kaewkhao

The Noether symmetry approach is useful tool to restrict the arbitrariness in a gravity theory when the equations of motion are underdetermined due to the high number of functions to be determined in the ansatz. We consider two…

General Relativity and Quantum Cosmology · Physics 2016-05-11 U. Camci , A. Yildirim , I. Basaran Oz

We consider Noether symmetry approach to find out exact cosmological solutions in $f(T)$-gravity. Instead of taking into account phenomenological models, we apply the Noether symmetry to the $f(T)$ gravity. As a result, the presence of such…

General Physics · Physics 2012-05-29 K. Atazadeh , F. Darabi

A canonical Hamiltonian is found for a reduced version of the Jackiw-Pi model for bilayer graphene. From the corresponding Lagrangian, the Noether point symmetries and conserved quantities are determined. The Noether symmetry group is the…

Mathematical Physics · Physics 2023-08-16 Fernando Haas

We consider modified teleparallel gravity, (f(T) gravity), as a framework to explain the present accelerated expansion of the universe. The matter component is assumed to be cold dark matter. To find the explicit form of the function $f$,…

General Relativity and Quantum Cosmology · Physics 2015-06-11 H. Mohseni Sadjadi

Noether symmetry has been invoked to explore the forms of a couple of coupling parameters and the potential appearing in a general scalar-tensor theory of gravity in the background of Robertson-Walker space-time. Exact solutions of…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-10 Abhik Kumar Sanyal , Ranajit Mandal
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