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Related papers: GR 20 Parallel Session A3: Modified Gravity

200 papers

Contents: We hear that... by Jorge Pullin * Reflections of a decade: Matters of Gravity and the Topical Group in Gravitation, by Beverly Berger 10 Years in Gravitational Wave Detection, by Peter Saulson Ten years of general relativity, some…

General Relativity and Quantum Cosmology · Physics 2009-03-10 Jorge Pullin

Research Briefs: Singularity Avoidance in Canonical Quantum Gravity, by Viqar Husain What's New in LIGO, by David Shoemaker Conference reports: Scanning New Horizons: GR Beyond 4 dimensions, by Donald Marolf Quantum Gravity in the Americas…

General Relativity and Quantum Cosmology · Physics 2016-08-31 David Garfinkle

We demonstrate that there does exist an equilibrium description of thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density $f(R, \phi, X)$,…

General Relativity and Quantum Cosmology · Physics 2011-08-05 Kazuharu Bamba , Chao-Qiang Geng , Shinji Tsujikawa

The paper summarizes the parallel session B3 {\em Analytic approximations, perturbation methods, and their applications} of the GR18 conference. The talks in the session reported notably recent advances in black hole perturbations and…

This work investigates the validity of the generalized second law of thermodynamics in modified f(R) Horava-Lifshitz gravity proposed by Chaichian et al (2010) [Class. Quantum Grav. 27 (2010) 185021], which is invariant under…

General Physics · Physics 2016-12-09 Surajit Chattopadhyay , Rahul Ghosh

This article has a dual purpose: i) to provide a flavor of the scientific highlights of the landmark conference, GR3, held in July 1962 at Jablonna, near Warsaw; and, ii) to present a bird's eye view of the tremendous advances that have…

General Relativity and Quantum Cosmology · Physics 2014-04-17 Abhay Ashtekar

Modified gravity (MOG) is a covariant, relativistic, alternative gravitational theory whose field equations are derived from an action that supplements the spacetime metric tensor with vector and scalar fields. Both gravitational (spin 2)…

General Relativity and Quantum Cosmology · Physics 2018-03-14 M. A. Green , J. W. Moffat , V. T. Toth

Universal thermodynamics for FRW model of the Universe bounded by apparent/event horizon has been considered for massive gravity theory. Assuming Hawking temperature and using the unified first law of thermodynamics on the horizon, modified…

General Relativity and Quantum Cosmology · Physics 2017-02-21 Subhajit Saha , Saugata Mitra , Subenoy Chakraborty

We review the effective field theory of modified gravity in which the Lagrangian involves three dimensional geometric quantities appearing in the 3+1 decomposition of space-time. On the flat isotropic cosmological background we expand a…

High Energy Physics - Theory · Physics 2015-02-24 Ryotaro Kase , Shinji Tsujikawa

These notes represent a summary of the introductory part of a course on modified gravity delivered at several Spanish Universities (Granada, Valencia, and Valladolid), at the University of Wisconsin-Milwaukee (WI, USA), and at the…

General Relativity and Quantum Cosmology · Physics 2011-12-13 Gonzalo J. Olmo

Motivated by Horava-Lifshitz gravity theory, we propose and investigate two kinds of modified gravity theories, the f(R) kind and the K-essence kind, in the Arnowitt-Deser-Misner (ADM) formalism. The f(R) kind includes one ultraviolet (UV)…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-07 Changjun Gao

The paper deals with universal thermodynamics for FRW model of the universe bounded by apparent (or event) horizon. Assuming Hawking temperature on the horizon, the unified first law is examined on the horizon for different gravity…

General Relativity and Quantum Cosmology · Physics 2016-05-17 Saugata Mitra , Subhajit Saha , Subenoy Chakraborty

This review explores modified theories of gravity, particularly $f(R)$ gravity, as extensions to General Relativity (GR) that offer alternatives to dark energy for explaining cosmic acceleration. These models generalize the Einstein-Hilbert…

General Relativity and Quantum Cosmology · Physics 2025-03-05 Rafid H. Dejrah

We propose a modified gravity theory by extending the Einstein-Hilbert action with an arbitrary function of the Ricci scalar and the Kretschmann scalar invariants. The resulting modified Friedmann equations for a spatially flat FRW universe…

General Relativity and Quantum Cosmology · Physics 2026-05-29 A. Dehyadegari , A. Sheykhi

The Special Issue on "Modified Gravity Approaches to the Tensions of $\Lambda$CDM"} in the Universe journal tackles significant challenges faced by the $\Lambda$CDM model, including discrepancies in the Hubble constant, growth rate of…

General Relativity and Quantum Cosmology · Physics 2024-04-23 Eleonora Di Valentino , Leandros Perivolaropoulos , Jackson Levi Said

Table of contents Editorial. Gravity News: Report on the APS topical group in gravitation, Beverly Berger. Research briefs: Gravitational microlensing and the search for dark matter, Bohdan Paczynski. Laboratory gravity: the G mystery,…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jorge Pullin

A seminar given about 30 years ago by Ruben Aldrovandi motivates this text where some reflexions about constructing theories that modify General Relativity are made. Two particular cases, the Brans-Dicke and Unimodular Gravity ones, are…

General Relativity and Quantum Cosmology · Physics 2023-11-28 Júlio C. Fabris

Table of contents Editorial Correspondents Gravity News: Open Letter to gravitational physicists, Beverly Berger A Missouri relativist in King Gustav's Court, Clifford Will Gary Horowitz wins the Xanthopoulos award, Abhay Ashtekar Research…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jorge Pullin

Contents: Editorial Correspondents News: - Topical Group News, by Jim Isenberg - We hear that..., by Jorge Pullin - The Chandra Satellite, by Beverly Berger Research Briefs: - Analytical event horizons of merging black holes, by Simonetta…

General Relativity and Quantum Cosmology · Physics 2009-03-10 Jorge Pullin

We study the dynamics of a modified-gravity theory, which is supplemented by an extended Gibbons-Hawking-York boundary term and incorporates diffeomorphism violation through nondynamical background fields denoted as $u$ and $s^{\mu\nu}$ in…

High Energy Physics - Theory · Physics 2022-09-07 Carlos M. Reyes , Marco Schreck