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Related papers: Unimodular $f(G)$ gravity

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In this work we introduce and study the unimodular-mimetic $f(\mathcal{G})$ gravity, where unimodular and mimetic constraints are incorporated through corresponding Lagrange multipliers. We present field equations governing this theory and…

General Relativity and Quantum Cosmology · Physics 2023-11-13 Adam Z. Kaczmarek , Dominik Szczęśniak

We extend the formalism of the Einstein-Hilbert unimodular gravity in the context of modified $F(R)$ gravity. After appropriately modifying the Friedmann-Robertson-Walker metric in a way that it becomes compatible to the unimodular…

General Relativity and Quantum Cosmology · Physics 2016-06-01 S. Nojiri , S. D. Odintsov , V. K. Oikonomou

We explore bounce cosmology in $F(\mathcal{G})$ gravity with the Gauss-Bonnet invariant $\mathcal{G}$. We reconstruct $F(\mathcal{G})$ gravity theory to realize the bouncing behavior in the early universe and examine the stability…

High Energy Physics - Theory · Physics 2014-04-17 Kazuharu Bamba , Andrey N. Makarenko , Alexandr N. Myagky , Sergei D. Odintsov

The so-called unimodular version of General Relativity is revisited. Unimodular gravity is constructed by fixing the determinant of the metric, what leads to the trace-free part of the equations instead of the usual Einstein field…

General Relativity and Quantum Cosmology · Physics 2016-06-22 Diego Saez-Gomez

We consider modifications of general relativity characterized by a special noncovariant constraint on metric coefficients, which effectively generates a perfect-fluid type of matter stress tensor in Einstein equations. Such class of…

General Relativity and Quantum Cosmology · Physics 2021-03-24 A. O. Barvinsky , N. Kolganov , A. Vikman

We investigate the inflationary realization in the context of unimodular $F(T)$ gravity, which is based on the $F(T)$ modification of teleparallel gravity, in which one imposes the unimodular condition through the use of Lagrange…

General Relativity and Quantum Cosmology · Physics 2017-06-29 Kazuharu Bamba , Sergei D. Odintsov , Emmanuel N. Saridakis

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

We reconstruct the geometrical $f(T)$ actions in the framework of unimodular $f(T)$ gravity. The unimodular $f(T)$ gravity yields stunning properties related to the generalized Friedmann equations. Indeed, it has been found that depending…

General Relativity and Quantum Cosmology · Physics 2017-01-03 S. B. Nassur , C. Ainamon , M. J. S. Houndjo , J. Tossa

We propose a novel modified gravity: unimodular generalization of the Born-Infeld-$f(R)$ gravity within the framework of cosmology. After formulating the action corresponding to the generalized Born-Infeld-$f(R)$ gravity, we present a…

General Relativity and Quantum Cosmology · Physics 2024-02-16 Salih Kibaroğlu , Sergei D. Odintsov , Tanmoy Paul

We extend the idea of unimodular gravity to the modified $f(R,T)$ theories. A new class of cosmological solutions, that the unimodular constraint on the metric imposes on the $f(R,T)$ theories, are studied. This extension is done in both…

General Relativity and Quantum Cosmology · Physics 2017-11-22 F. Rajabi , K. Nozari

We study global scale invariance along with the unimodular gravity in the vacuum. The global scale invariant gravitational action which follows the unimodular general coordinate transformations is considered without invoking any scalar…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-01 Naveen K. Singh

This paper is devoted to investigate the recently proposed modified Gauss-Bonnet $f(\mathcal{G},T)$ gravity, with $\mathcal{G}$, the Gauss-Bonnet term, coupled with ${T}$, the trace of energy-momentum tensor. We have used the Noether…

General Relativity and Quantum Cosmology · Physics 2017-07-12 M. Farasat Shamir , Mushtaq Ahmad

We study a theory of gravity of the form $f(\mathcal{G})$ where $\mathcal{G}$ is the Gauss-Bonnet topological invariant without considering the standard Einstein-Hilbert term as common in the literature, in arbitrary $(d+1)$ dimensions. The…

General Relativity and Quantum Cosmology · Physics 2020-01-30 Francesco Bajardi , Konstantinos F. Dialektopoulos , Salvatore Capozziello

Unimodular gravity is based on a modification of the usual Einstein-Hilbert action that allows one to recover general relativity with a dynamical cosmological constant. It also has the interesting property of providing, as the momentum…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Dah-Wei Chiou , Marc Geiller

In this paper, we study anisotropic universe using Noether symmetries in modified gravity. In particular, we choose locally rotationally symmetric Bianchi type-$I$ universe for the analysis in $f(R,\mathcal{G})$ gravity, where $R$ is the…

General Relativity and Quantum Cosmology · Physics 2017-05-18 M. Farasat Shamir , Fiza Kanwal

In this paper we investigate how to realize various quite well known cosmological bouncing models in the context of the recently developed unimodular $F(R)$ gravity. Particularly, we shall study the matter bounce scenario, the singular…

General Relativity and Quantum Cosmology · Physics 2016-05-04 S. Nojiri , S. D. Odintsov , V. K. Oikonomou

We study the special class of the exact solutions in cosmological models based on the Generalized Scalar-Tensor Gravity with non-minimal coupling of a scalar field to the Ricci scalar and to the Gauss-Bonnet scalar in 4D Friedmann universe…

General Relativity and Quantum Cosmology · Physics 2019-07-17 Igor V. Fomin , Sergey V. Chervon

We develop the $n$-dimensional cosmology for $f(\mathcal{G})$ gravity, where $\mathcal{G}$ is the \emph{Gauss-Bonnet} topological invariant. Specifically, by the so-called Noether Symmetry Approach, we select $f(\mathcal{G})\simeq…

General Relativity and Quantum Cosmology · Physics 2021-11-29 Francesco Bajardi , Salvatore Capozziello

We study the evolution of cosmological perturbations in f(G) gravity, where the Lagrangian is the sum of a Ricci scalar R and an arbitrary function f in terms of a Gauss-Bonnet term G. We derive the equations for perturbations assuming…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Antonio De Felice , David F. Mota , Shinji Tsujikawa

In this paper we present a general vacuum solution of the modified Gauss-Bonnet gravity equations for the Friedmann-Lema\^itre-Robertson-Walker metric. We use an ansatz to reduce the gravitational equations to an ordinary differential…

General Relativity and Quantum Cosmology · Physics 2024-03-22 Maria V. Shubina
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