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In this work, we study the large scale structure formation in the modified gravity in the framework of Palatini formalism and compare the results with the equivalent smooth dark energy models as a tool to distinguish between these models.…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Shant Baghram , Sohrab Rahvar

By parametrizing the action integral for the standard Schrodinger equation we present a derivation of the recently proposed method for quantizing a parametrized theory. The reformulation suggests a natural extension from conventional to…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Charles H-T Wang , Smaragda Kessari , Edward R Irvine

We investigate the weak-field, post-Newtonian expansion to the solution of the field equations in Chern-Simons gravity with a perfect fluid source. In particular, we study the mapping of this solution to the parameterized post-Newtonian…

High Energy Physics - Theory · Physics 2008-11-26 Stephon Alexander , Nicolas Yunes

We investigate the cosmological implications of modified gravities induced by the quantum fluctuations of the gravitational metric. If the metric can be decomposed as the sum of the classical and of a fluctuating part, of quantum origin,…

General Relativity and Quantum Cosmology · Physics 2016-08-02 Xing Liu , Tiberiu Harko , Shi-Dong Liang

We establish a well-posedness theory for the f(R) theory of modified gravity, which is a generalization of Einstein's theory of gravitation. The scalar curvature R of the spacetime, which arises in the integrand of the Einstein-Hilbert…

Analysis of PDEs · Mathematics 2014-12-30 Philippe G. LeFloch , Yue Ma

Parametrized field theory (PFT) is free field theory on flat spacetime in a diffeomorphism invariant disguise. It describes field evolution on arbitrary foliations of the flat spacetime instead of only the usual flat ones, by treating the…

General Relativity and Quantum Cosmology · Physics 2015-01-30 Madhavan Varadarajan

After a brief review of topological gravity, we present a superspace approach to this theory. This formulation allows us to recover in a natural manner various known results and to gain some insight into the precise relationship between…

General Relativity and Quantum Cosmology · Physics 2009-11-10 C. P. Constantinidis , A. Deandrea , F. Gieres , M. Lefrancois , O. Piguet

The Generalized Uncertainty Principle (GUP) has emerged in numerous attempts to a theory of quantum gravity and predicts the existence of a minimum length in Nature. In this work, we consider two cosmological models arising from Friedmann…

General Relativity and Quantum Cosmology · Physics 2022-04-12 Serena Giardino , Vincenzo Salzano

Many modified gravity theories are under consideration in cosmology as the source of the accelerated expansion of the universe and linear perturbation theory, valid on the largest scales, has been examined in many of these models. However,…

General Relativity and Quantum Cosmology · Physics 2015-11-06 Daniel B Thomas , Marco Bruni , Kazuya Koyama , Baojiu Li , Gong-Bo Zhao

This thesis investigates modified teleparallel gravity models with a scalar field and teleparallel boundary terms, focusing on their cosmological implications for late-time cosmic acceleration. Teleparallel gravity, is an alternative to…

General Relativity and Quantum Cosmology · Physics 2025-01-22 S. A. Kadam

This review presents a comprehensive overview of Myrzakulov gravity, highlighting key developments and significant results shaping the theory. It examines the foundational principles, field equations, and the role of non-metricity and…

General Relativity and Quantum Cosmology · Physics 2025-04-04 Davood Momeni , Ratbay Myrzakulov

This study explores the link between Modified Gravity and modifications of phase space volume. Analyzing Fermi gas modifications {in the non-relativistic limit of the} Ricci-based gravities, we derive a generalized partition function in the…

General Relativity and Quantum Cosmology · Physics 2024-01-10 Aneta Wojnar

We propose a new cosmological framework in which the strength of the gravitational force acted on dark matter at late time can be weaker than that on the standard matter fields without introducing extra gravitational degrees of freedom. The…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-14 Antonio De Felice , Shinji Mukohyama

Hybrid metric-Palatini gravity unifies the metric and Palatini formalisms while preserving a propagating scalar degree of freedom, offering a compelling route to modified gravity consistent with current observations. Motivated by this…

General Relativity and Quantum Cosmology · Physics 2026-03-26 David S. Pereira , Salvatore Capozziello , Francisco S. N Lobo , José Pedro Mimoso

In this study, we investigate the cosmological history within the framework of modified $f(Q)$ gravity, which proposes an alternative theory of gravity where the gravitational force is described by a non-metricity scalar. By employing a…

General Relativity and Quantum Cosmology · Physics 2023-08-30 N. Myrzakulov , M. Koussour , A. Mussatayeva

It is known that the Einstein-Hilbert action with a positive cosmological constant can be represented as a perturbation of the SO(4,1) BF theory by a symmetry-breaking term quadratic in the B field. Introducing fermionic matter generates…

General Relativity and Quantum Cosmology · Physics 2015-06-25 A. Mikovic

We propose a cosmological model in the framework of the Poincar\'e gauge theory of gravity (PG). The gravitational Lagrangian is quadratic in curvature and torsion. In our specific model, the Lagrangian contains (i) the curvature scalar $R$…

General Relativity and Quantum Cosmology · Physics 2011-02-25 Peter Baekler , Friedrich W. Hehl , James M. Nester

{\bf{CONTEXT}}: In this work we propose a modified gravity action $f(R)=(R^n-R^n_{0})^{1/n}$ with two free parameters of $n$ and $R_{0}$ and derive the dynamics of a universe for this action in the Palatini formalism. {\bf {AIM}}: We do a…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 Shant Baghram , M. Sadegh Movahed , Sohrab Rahvar

A new class of modified theories of gravity, consisting of the superposition of the metric Einstein-Hilbert Lagrangian with an $f(\cal R)$ term constructed \`{a} la Palatini was proposed recently. The dynamically equivalent scalar-tensor…

General Relativity and Quantum Cosmology · Physics 2013-04-05 Salvatore Capozziello , Tiberiu Harko , Tomi S. Koivisto , Francisco S. N. Lobo , Gonzalo J. Olmo

A new approach is suggested which allows to describe phenomenologically arbitrary topologies of the Universe. It consists in a generalizaton of third quantization. This quantization is carried out for the case of asymptotic closeness to a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 A. A. Kirillov
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