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Related papers: Gravitational Perturbation in Nonlocal Modified To…

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We present a class of modified-gravity theories which we call ultra-local models. We add a scalar field, with negligible kinetic terms, to the Einstein-Hilbert action. We also introduce a conformal coupling to matter. This gives rise to a…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 Philippe Brax , Luca Alberto Rizzo , Patrick Valageas

Emergent modified gravity is a post-Einsteinian gravitational theory where spacetime geometry is not fundamental but rather emerges from the gravitational degrees of freedom in a non-trivial way. The specific relationship between geometry…

General Relativity and Quantum Cosmology · Physics 2024-12-23 Martin Bojowald , Erick I. Duque , S. Shankaranarayanan

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

We provide a systematic and updated discussion of a research line carried out by our group over the last few years, in which gravity is modified at cosmological distances by the introduction of nonlocal terms, assumed to emerge at an…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-15 Enis Belgacem , Yves Dirian , Andreas Finke , Stefano Foffa , Michele Maggiore

Even if the fundamental action of gravity is local, the corresponding quantum effective action, that includes the effect of quantum fluctuations, is a nonlocal object. These nonlocalities are well understood in the ultraviolet regime but…

High Energy Physics - Theory · Physics 2018-03-21 Enis Belgacem , Yves Dirian , Stefano Foffa , Michele Maggiore

Region of trapped null geodesics hidden inside of extremely compact objects is of astrophysical importance because of trapping of gravitational waves, or neutrinos. The trapping effect of null geodesics was extensively studied for…

General Relativity and Quantum Cosmology · Physics 2021-08-24 Zdeněk Stuchlík , Jaroslav Vrba

This thesis investigates compact astrophysical objects within modified theories of gravity, focusing on neutron stars and strange stars. The work studies their internal structure, equilibrium, and stability in gravitational frameworks based…

General Relativity and Quantum Cosmology · Physics 2026-05-26 Sneha Pradhan

Prior change is discussed in observational constraints studies of nonlocally modified gravity. In the latter, a model characterized by a modification of the form $\sim m^2 R\Box^{-2}R$ to the Einstein-Hilbert action was compared against the…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-25 Yves Dirian

A nonlocal form of the effective gravitational action could cure the unboundedness of euclidean gravity with Einstein action. On sub-horizon length scales the modified gravitational field equations seem compatible with all present tests of…

General Relativity and Quantum Cosmology · Physics 2015-06-25 C. Wetterich

In the context of linear $f(\mathcal{R},T)=\mathcal{R}+\chi T$ gravity, where $\mathcal{R}$ is the Ricci scalar, $T$ is the trace of the energy-momentum tensor, and $\chi$ is a dimensionless parameter, we have obtained exact analytical and…

General Relativity and Quantum Cosmology · Physics 2023-01-30 Thomas D. Pappas , Camilo Posada , Zdeněk Stuchlík

Nonlocal gravity has been shown to provide a phenomenologically viable infrared modification of GR. A natural question is whether the required nonlocality can emerge from perturbative quantum loop corrections due to light particles. We show…

High Energy Physics - Theory · Physics 2016-04-06 Michele Maggiore

The analysis of measurements of accelerated observers in Minkowski spacetime has led to the development of nonlocal special relativity theory. Inertia and gravitation are intimately connected in accordance with the principle of equivalence.…

General Relativity and Quantum Cosmology · Physics 2012-10-11 Bahram Mashhoon

This paper presents a rigorous mathematical analysis of transverse electromagnetic (EM) field concentration between two adjacent obstacles within the framework of the quasi-static approximation. We investigate three degenerate conductivity…

Analysis of PDEs · Mathematics 2026-04-23 Yueguang Hu , Hongjie Li , Hongyu Liu

We present a toy model of a generic five-dimensional warped geometry in which the 4D graviton is not fully localized on the brane. Studying the tensor sector of metric perturbation around this background, we find that its contribution to…

High Energy Physics - Theory · Physics 2010-12-03 M. Shaposhnikov , P. Tinyakov , K. Zuleta

We investigate gravitational radiation in the linear approximation within the framework of the recent nonlocal generalization of Einstein's theory of gravitation. In this theory, nonlocality can simulate dark matter; in fact, in the…

General Relativity and Quantum Cosmology · Physics 2015-06-11 C. Chicone , B. Mashhoon

The M$\o$ller tetrad gravitational energy-momentum expression was recently evaluated for a small vacuum region using orthonormal frames adapted to Riemann normal coordinates. However the result was not proportional to the Bel-Robinson…

General Relativity and Quantum Cosmology · Physics 2008-09-24 Lau Loi So

The role of entanglement in determining the non-classicality of a given interaction has gained significant traction over the last few years. In particular, as the basis for new experimental proposals to test the quantum nature of the…

Quantum Physics · Physics 2023-11-15 A. Douglas K. Plato , Dennis Rätzel , Chuanqi Wan

Using the gravitational decoupling by the minimal geometric deformation approach, we build an anisotropic version of the well-known Tolman VII solution, determining an exact and physically acceptable interior two-fluid solution that can…

General Relativity and Quantum Cosmology · Physics 2019-10-23 Sudipta Hensh , Zdeněk Stuchlík

Gravitational waves allow us to test general relativity in the highly dynamical regime. While current observations have been consistent with waves emitted by quasi-circular binaries, eccentric binaries may also produce detectable signals in…

General Relativity and Quantum Cosmology · Physics 2020-08-26 Blake Moore , Nicolás Yunes

We study the excitation of nonaxisymmetric modes in the post-merger phase of binary compact object mergers and the associated gravitational wave emission. Our analysis is based on general-relativistic simulations, in the spatial conformal…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Nikolaos Stergioulas , Andreas Bauswein , Kimon Zagkouris , Hans-Thomas Janka
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