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Related papers: Non-local gravity in bouncing cosmology scenarios

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The present work deals with Einstein-aether Scalar tensor gravity in the background of homogeneous and isotropic flat FLRW space-time model. The Noether symmetry vector identifies a transformation in the augmented space so that the field…

General Relativity and Quantum Cosmology · Physics 2024-07-12 Dipanakr Laya , Roshni Bhaumik , Sourav Dutta , Subenoy Chakraborty

The aim of this paper is to reconstruct and analyze the stability of some cosmological models against linear perturbations in $f(\mathcal{G},T)$ gravity ($\mathcal{G}$ and $T$ represent the Gauss-Bonnet invariant and trace of the…

General Relativity and Quantum Cosmology · Physics 2017-06-22 M. Sharif , Ayesha Ikram

This paper analyzes the possibility of bouncing and non-bouncing universes in the framework of four-dimensional Einstein-Gauss-Bonnet (4D-EGB) gravity, corresponding respectively to negative and positive coupling constants $\lambda$ of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-11 H. Khodabakhshi , M. Farhang , H. Lü

The role of an exponential function of the scalar curvature in the modified gravity is analyzed. Two models are proposed. A toy model that complies with local and cosmological constraints and gives appropriate qualitative description of the…

General Relativity and Quantum Cosmology · Physics 2020-07-15 L. N. Granda

We explore the cosmological implications of the local limit of nonlocal gravity, which is a classical generalization of Einstein's theory of gravitation within the framework of teleparallelism. An appropriate solution of this theory is the…

General Relativity and Quantum Cosmology · Physics 2024-04-17 Javad Tabatabaei , Abdolali Banihashemi , Shant Baghram , Bahram Mashhoon

A non-local modified gravity model with an analytic function of the d'Alembert operator that has been proposed as a possible way of resolving the singularities problems in cosmology is considered. We show that the anzats that is usually…

General Relativity and Quantum Cosmology · Physics 2015-01-09 Alexey S. Koshelev , Sergey Yu. Vernov

De Sitter solutions play an important role in cosmology because the knowledge of unstable de Sitter solutions can be useful to describe inflation, whereas stable de Sitter solutions are often used in models of late-time acceleration of the…

General Relativity and Quantum Cosmology · Physics 2021-05-18 Sergey Vernov , Ekaterina Pozdeeva

We re-analyze the nonlocal gravity model of Deser and Woodard which was proposed to account for the current phase of cosmic acceleration. We show that the growth of perturbations predicted by this nonlocal gravity model when its background…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-05 Sohyun Park , Arman Shafieloo

We investigate the cosmology of a class of model with noncanonical scalar field and matter in an anisotropic time dependent background. Writing the Einstein Equations in terms of dimensionless dynamical variables appropriately defined for…

General Relativity and Quantum Cosmology · Physics 2016-02-17 Sukanta Panda , Manabendra Sharma

In this paper we have investigated the cosmological dynamics of non-locally corrected gravity involving a function of the inverse d'Alembertian of the Ricci scalar, $f(\Box^{-1} R))$. Casting the dynamical equations into local form, we…

High Energy Physics - Theory · Physics 2008-11-26 S. Jhingan , S. Nojiri , S. D. Odintsov , M. Sami , I Thongkool , S. Zerbini

We investigate de Sitter solutions in non-local gravity as well as in non-local gravity with Lagrange constraint multiplier. We examine a condition to avoid a ghost and discuss a screening scenario for a cosmological constant in de Sitter…

High Energy Physics - Theory · Physics 2015-05-27 Kazuharu Bamba , Shin'ichi Nojiri , Sergei D. Odintsov , Misao Sasaki

We derive the master equations governing axial and polar gravitational perturbations of a generic static and spherically symmetric black hole spacetime within the framework of the revised Deser--Woodard nonlocal gravity theory. We then…

General Relativity and Quantum Cosmology · Physics 2026-01-19 Rocco D'Agostino , Vittorio De Falco

Recent data on supernovae favor high values of the cosmological constant. Spacetimes with a cosmological constant have non-relativistic kinematics quite different from Galilean kinematics. De Sitter spacetimes, vacuum solutions of…

General Relativity and Quantum Cosmology · Physics 2009-10-31 R. Aldrovandi , A. L. Barbosa , L. C. B. Crispino , J. G. Pereira

In this work we study non-singular{ bounce cosmology} in the context of the Lagrange multiplier generalized $F(R)$ gravity theory of gravity. We specify our study by using a specific variant form of the well known matter{ bounce cosmology},…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Shin'ichi Nojiri , S. D. Odintsov , V. K. Oikonomou , Tanmoy Paul

A theory of gravitation is constructed in which all homogeneous and isotropic solutions are nonsingular, and in which all curvature invariants are bounded. All solutions for which curvature invariants approach their limiting values approach…

General Relativity and Quantum Cosmology · Physics 2009-10-22 R. Brandenberger , V. Mukhanov , A. Sornborger

We present a gauge-invariant treatment of singularity resolution using loop quantum gravity techniques with respect to local SU(2) transformations. Our analysis reveals many novel features of quantum geometry which were till now hidden in…

General Relativity and Quantum Cosmology · Physics 2020-03-31 Klaus Liegener , Parampreet Singh

We present the graviton propagator for an infinite derivative, $D$-dimensional, non-local action, up to quadratic order in curvature around a Minkowski background, and discuss the conditions required for this class of gravity theory to be…

High Energy Physics - Theory · Physics 2015-12-30 Aindriu Conroy , Anupam Mazumdar , Spyridon Talaganis , Ali Teimouri

Symmetric teleparallel gravity offers to reformulate the gravitational formalism without the presence of curvature and torsion with the help of non-metricity tensors. Interestingly, Symmetric teleparallel gravity can be formulated…

General Relativity and Quantum Cosmology · Physics 2023-07-12 Gaurav N. Gadbail , Ameya Kolhatkar , Sanjay Mandal , P. K. Sahoo

In this thesis, we explore three phenomenological alternatives to the current paradigm of the standard inflationary big bang scenario. The three alternative themes are spin torsion (or Einstein-Cartan-Kibble-Sciama) theories, extra…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Bernard Leong

This article explores matter bounce non-singular cosmology in $f(R,L_m)$ gravity. We consider two non-linear $f(R,L_m)$ functional forms, specifically, $f(R,L_m) = \frac{R}{2} + \lambda R^2 + \alpha L_m$ and $f(R,L_m) = \frac{R}{2} + L_m…

General Relativity and Quantum Cosmology · Physics 2024-05-17 Lakhan V. Jaybhaye , Raja Solanki , P. K. Sahoo