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We show that a single constrained scalar field with non-minimal coupling to gravity can give rise to an accelerating Universe. First, we consider this model in the absence of external matter. In the original Jordan frame, we show that the…

High Energy Physics - Theory · Physics 2025-07-02 Anamaria Hell , Misao Sasaki

We take J. S. Bell's commendation of ``frame-dependent'' perspectives to the limit here, and consider motion on a ``map'' of landmarks and clocks fixed with respect to a single arbitrary inertial-reference frame. The metric equation…

Physics Education · Physics 2008-02-03 P. Fraundorf

We offer a concise and direct way to derive the bending angle of light (i.e. as generally called, gravitational lensing), while light grazes a star, through the approach suggested earlier by the first author, which is fundamentally based on…

General Physics · Physics 2014-01-15 Tolga Yarman , Alexander Kholmetskii , Metin Arik

A new approach in the Newtonian space and time, based upon the assumption that inertial mass is the quantitative measure of the matter. It has been shown that in case of a special physical system, a supposed matter transfer may reproduce…

General Physics · Physics 2013-08-13 P. Doleschall

Ever since the work of von Ignatowsky circa 1910 it has been known (if not always widely appreciated) that the relativity principle, combined with the basic and fundamental physical assumptions of locality, linearity, and isotropy, leads…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Valentina Baccetti , Kyle Tate , Matt Visser

General relativity and quantum mechanics are perhaps the two most successful theories of the XXth century. Despite their impressive accurate predictions, they are both valid at their own scales and do not seem to be expressible using the…

General Physics · Physics 2019-03-01 Benoît Pairet

The time evolution of the universe is usually mathematically described under a continuous time and thus time reversible. Here, the consequences of studying the evolution of a homogenous isotropic universe by time continuous reversible…

General Physics · Physics 2019-10-23 Roland Riek

Proceeding like Newton with a discrete time approach of motion and a geometrical representation of velocity and acceleration, we obtain Kepler's laws without solving differential equations. The difficult part of Newton's work, when it calls…

Popular Physics · Physics 2009-11-13 J. -P. Provost , C. Bracco

Based on the consideration of naturalness and physical facts in Einstein's theories of relativity, a nontrivial spacetime physical picture, which has a slight difference from the standard one, is introduced by making a further distinction…

High Energy Physics - Theory · Physics 2016-01-27 ChiYi Chen

It is often said that in general relativity time does not exist. This is because the Einstein equations generate motion in time that is a symmetry of the theory, not true time evolution. In quantum gravity, the timelessness of general…

General Relativity and Quantum Cosmology · Physics 2009-09-11 Fotini Markopoulou

The space-time of modern physics is tailored on light. We rigorously construct the basic entities needed by kinematics: geometry of the physical space and time, using as tool electromagnetic waves, and particularly light-rays. After such a…

History and Philosophy of Physics · Physics 2015-12-15 Zoltan Neda

Derivation of the Lorentz transformation without the use of Einstein's Second Postulate is provided along the lines of Ignatowsky, Terletskii, and others. This is a write-up of the lecture first delivered in PHYS 4202 E&M class during the…

Classical Physics · Physics 2023-09-26 Andrei Galiautdinov

An odd look at "standard" physics (Galileo, Newton, Einstein, Dirac) leading to a radical change of our concept of inertial motion and to new heuristic approaches of gravitation and the cosmological constant.

General Physics · Physics 2015-05-27 Jean-Pierre Provost

By using an unmodified Einstein gravity theory it is shown that all of the speeding-up effects taking place in the current universe are entirely due to the quantum effects associated with the background radiation or to the combination of…

Astrophysics · Physics 2009-11-11 Pedro F. Gonzalez-Diaz , Alberto Rozas-Fernandez

All the relativistic cosmological models of the universe, except Einstein's static model, imply that the 3-space of the spacetime of the universe is also expanding apart from the matter and the radiation in it. However, there is no…

General Physics · Physics 2009-01-15 R. K. Thakur

As was recently shown, non-relativistic quantum theory can be derived by means of a projection method from a continuum of classical solutions for (massive) particles. In this paper we show that Maxwell's equations in empty space can be…

Quantum Physics · Physics 2024-09-09 Ulf Klein

From the Physics point of view, time is now best described through General Relativity, as part of space-time which is a dynamical object encoding gravity. Time possesses also some intrinsic irreversibility due to thermodynamics, quantum…

General Relativity and Quantum Cosmology · Physics 2009-03-30 Florian Girelli , Stefano Liberati , Lorenzo Sindoni

Besides two fundamental postulates, (i) the principle of relativity and (ii) the constancy of the speed of light in all inertial frames of reference, special relativity uses the assumption about the Euclidean structures of gravity-free…

General Physics · Physics 2015-06-26 Jian-Miin Liu

We show that the relativistic expressions for momentum and energy as well as the way in which they transform could be derived without involving collisions and conservation laws. Our approach involves relativistic kinematics via the addition…

General Physics · Physics 2008-10-20 Bernhard Rothenstein , Stefan Popescu

General relativity describes the gravitational field geometrically and in a self-interacting way because it couples to all forms of energy, including its own. Both features make finding a quantum theory difficult, yet it is important in the…

General Relativity and Quantum Cosmology · Physics 2011-09-02 Martin Bojowald