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A simple and {\it innocent} modification of Poisson's equation leads to a modified Newtonnian theory of gravitation where a localized and {\it positive} energy density of the gravitational field contributes to its own source. The result is…

Classical Physics · Physics 2009-05-17 Lluis Bel

A new concept of internal time (viewed as a scalar temporal field) is introduced which allows one to solve the energy problem in General Relativity. The law of energy conservation means that the total energy density of the full system of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ivanhoe B. Pestov

We find a (quasi-)local first law of thermodynamics, $\Delta E = T \Delta S - W$, connecting gravitational entropy, $S$, with matter energy and work. For Einstein gravity $S$ is the Bekenstein-Hawking entropy, while for general theories of…

General Relativity and Quantum Cosmology · Physics 2020-11-16 Maulik Parikh , Sudipta Sarkar , Andrew Svesko

We show that if one starts with a Universe with some matter and a cosmological constant, then quantum mechanics naturally induces an attractive gravitational potential and an effective Newton's coupling. Thus gravity is an emergent…

General Relativity and Quantum Cosmology · Physics 2022-01-26 Saurya Das , Sourav Sur

Starting from the action function, we have derived a theoretical background that leads to the quantization of gravity and the deduction of a correlation between the gravitational and the inertial masses, which depends on the kinetic…

General Physics · Physics 2014-02-18 Fran De Aquino

An approach to modelling the universe based on the requisites of gravitational energy. This model is explained as it relates to the stages of the universal life cycle and the continued existence of the universe as it is known today. The…

Astrophysics · Physics 2007-05-23 Anthony Baldocchi

In a foregoing paper, gravity has been interpreted as the pressure force exerted on matter at the scale of elementary particles by a perfect fluid. Under the condition that Newtonian gravity must be recovered in the incompressible case, a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Mayeul Arminjon

The confrontation between Einstein's gravitation theory and experimental results, notably binary pulsar data, is summarized and its significance discussed. Experiment and theory agree at the 10^{-3} level. All the basic structures of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Thibault Damour

In 1905, Einstein carried out his first derivation of the mass-energy equivalence by studying in different reference frames the energy balance of a body emitting electromagnetic radiation and assuming special relativity as a prerequisite.…

General Physics · Physics 2022-09-14 Germano D'Abramo

According to recent observations, the Dark Energy would represent 70% of the content of our Universe. The most popular way to account for this Dark Energy make use of the Cosmological Constant introduced by Einstein. However, some…

General Physics · Physics 2018-04-04 Bernard Castaing

We generalize the $f(R)$ type gravity models by assuming that the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar $R$ and of the matter Lagrangian $L_m$. We obtain the gravitational field equations in the…

General Relativity and Quantum Cosmology · Physics 2011-02-09 Tiberiu Harko , Francisco S. N. Lobo

General relativity is a set of physical and geometric principles, which lead to a set of (Einstein) field equations that determine the gravitational field, and to the geodesic equations that describe light propagation and the motion of…

General Relativity and Quantum Cosmology · Physics 2017-04-19 Alan A. Coley , David L. Wiltshire

We have recently shown that both passive and active gravitational masses of a composite body are not equivalent to its energy due to some quantum effects. We have also suggested an idealized and more realistic experiments to detect the…

General Relativity and Quantum Cosmology · Physics 2017-03-02 Andrei G Lebed

The simplest quantum composite body, a hydrogen atom, is considered in the presence of a weak external gravitational field. We define an operator for the passive gravitational mass of the atom in the post-Newtonian approximation of the…

General Relativity and Quantum Cosmology · Physics 2014-04-17 Andrei G. Lebed

A fraction of energy is theoretically predicted to be captured from electromagnetic field to form a gravitating mass, when a low-mass charged particle enters the strong field from a region of no electromagnetism. In this paper the mass…

General Physics · Physics 2009-08-09 Zihua Weng

Einstein's equations in matter are gravitational analogues of Maxwell's equations in matter, providing an effective classical description of gravitational fields. We derive Einstein's equations in matter for relativistic fluids, and use…

General Relativity and Quantum Cosmology · Physics 2020-05-29 Pavel Kovtun , Ashish Shukla

Recently, we have suggested some semi-quantitative Hamiltonian for an electron in a hydrogen atom in a weak gravitational field, which takes into account quantum effects of electron motion in the atom. We have shown that this Hamiltonian…

General Relativity and Quantum Cosmology · Physics 2016-10-12 Andrei G. Lebed

A definition of gravitational energy is proposed for any theory described by a diffeomorphism-invariant Lagrangian. The mathematical structure is a Noether- current construction of Wald involving the boundary term in the action, but here it…

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

The classical gravitational two-body problem is generalized in order to be applicable also to weak gravitational fields. The equation of motion holds both for terrestrial and large cosmic scales, the Newtonian gravitational law represents a…

Astrophysics of Galaxies · Physics 2020-05-18 Jozef Klačka

These notions in the title are of fundamental importance in any branch of physics. However, there have been great difficulties in finding physically acceptable definitions of them in general relativity since Einstein's time. I shall explain…

General Relativity and Quantum Cosmology · Physics 2016-05-18 Mu-Tao Wang
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