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Dark energy density predicted and explained

EPL 2019年第1期125卷

作者： Nesbet, R. K. IBM Almaden Res Ctr 650 Harry Rd San Jose CA 95120 USA

It has recently been shown that the observed Hubble function for cosmological expansion can be fitted accurately back to redshift unity (7.33 Gyr ago) with only one free constant, while neglecting cosmic curvature and mass density, using the modified Friedmann equation implied by subjecting the Higgs scalar field model to conformal Weyl scaling symmetry. It is shown here that the implied dark energy parameter is produced by dressing the bare scalar field by the neutral gauge boson field induced by weak cosmological time dependence of the conformal Higgs model. Predicted persistent cosmic acceleration is consistent with the nonclassical acceleration parameter inferred by conformal theory from observed excessive galactic rotation velocities and dark galactic halos, all without dark matter. Copyright (C) EFLA, 2019

关键词： Dark energy Cosmology fundamental problems and general formalism

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Abbott-Deser energy in connection with Thirring's superpotentials

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EPL 2018年第5期122卷

作者： Baykal, Ahmet Dereli, Tekin Nigde Omer Halisdemir Univ Fac Arts & Sci Dept Phys Bor Yolu Uzeri Merkez Kampus TR-51240 Nigde Turkey Koc Univ Dept Phys Coll Sci TR-34450 Istanbul Turkey

We linearize vacuum Einstein field equations with a cosmological constant around a curved background to elaborate on the reconstruction of the Abbott-Deser charges and incorporate a spin connection into the definition... 详细信息

关键词： Classical general relativity fundamental problems and general formalism

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What is the gravitational mass when energy and inertial mass are not equivalent?

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EPL 2018年第2期123卷

作者： Castaing, B. Lab Ecoulements Geophys & Ind Domaine UnivCS 40700 F-38058 Grenoble 9 France

In this paper, we discuss some consequences of the existence in the Universe of particles for which energy minimum happens at a finite momentum (like rotons in superfluid He-4). The most striking consequence for a gas of such particles is that its inertial mass is not related to its energy. Thus, a natural question is the value of its gravitational mass. Assuming the equivalence of inertial and gravitational masses, we find that this gas contributes increasingly to the total mass of the expanding Universe. However, it implies to modify the Einstein equations of Central Relativity. Using a simple example borrowed from condensed matter, we show why such a modification has to be expected. Looking for a possible outcome of such particles in the observations, we compare the behavior of the gas they would form with the behavior of Dark Energy. Copyright (C) EPLA, 2018

关键词： fundamental problems and general formalism Experimental tests of gravitational theories Modified theories of gravity

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Relativistic Newtonian dynamics for objects and particles

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EPL 2017年第4期117卷

作者： Friedman, Y. Jerusalem Coll Technol Jerusalem Israel

Relativistic Newtonian Dynamics (RND) was introduced in a series of recent papers by the author, in partial cooperation with J. M. Steiner. RND was capable of describing non-classical behavior of motion under a central attracting force. RND incorporates the influence of potential energy on spacetime in Newtonian dynamics, treating gravity as a force in flat spacetime. It was shown that this dynamics predicts accurately gravitational time dilation, the anomalous precession of Mercury and the periastron advance of any binary. In this paper the model is further refined and extended to describe also the motion of both objects with non-zero mass and massless particles, under a conservative attracting force. It is shown that for any conservative force a properly defined energy is conserved on the trajectories and if this force is central, the angular momentum is also preserved. An RND equation of motion is derived for motion under a conservative force. As an application, it is shown that RND predicts accurately also the Shapiro time delay-the fourth test of GR. Copyright (C) EPLA, 2017

关键词： Relativity and gravitation fundamental problems and general formalism

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∞-∞: Vacuum energy and virtual black holes

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EPL 2016年第2期116卷

作者： Addazi, Andrea Univ Aquila Dipartimento Fis I-67010 Coppito AQ Italy Lab Nazl Gran Sasso I-67010 Assergi AQ Italy

We discuss other contributions to the vacuum energy of quantum field theories and quantum gravity, which have not been considered in the literature. As is well known, the presence of virtual particles in vacuum provides the so famous and puzzling contributions to the vacuum energy. In fact, these mainly come from loop integrations over the four-momenta space. However, we argue that these also imply the presence of a mass density of virtual particles in every volume cell of space-time. The most important contribution comes from quantum gravity S-2 xS(2) bubbles, corresponding to virtual black hole pairs. The presence of virtual masses could lead to another paradox: the space-time itself would have an intrinsic virtual mass density contribution leading to a disastrous contraction - as is known, no negative masses exist in general relativity. We dub this effect the cosmological problem of second type: if not other counter-terms existed, the vacuum energy would be inevitably destabilized by virtual-mass contributions. It would be conceivable that the cosmological problem of second type could solve the first one. Virtual masses renormalize the vacuum energy to an unpredicted parameter, as in the renormalization procedure of the Standard Model charges. In the limit of M-Pl -> infinity (Pauli-Villars limit), virtual black holes have a mass density providing an infinite counter-term to the vacuum energy divergent contribution M-Pl -> infinity (assuming M-UV = M-Pl). Therefore, in the same Schwinger-Feynman-Tomonaga attitude, the problem of a divergent vacuum energy could be analogous to the put-by-hand procedure used for Standard Model parameters. Copyright (C) EPLA, 2016

关键词： fundamental problems and general formalism Quantum aspects of black holes, evaporation, thermodynamics Quantum fields in curved spacetime

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Construction of energy-momentum tensor of gravitation

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INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS 2016年第1期13卷

作者： Bamba, Kazuharu Shimizu, Katsutaro Fukushima Univ Fac Symbiot Syst Sci Div Human Support Syst Fukushima 9601296 Japan Univ Aizu Div Comp Sci Aizu Wakamatsu Fukushima 9658580 Japan

We construct the gravitational energy-momentum tensor in general relativity through the Noether theorem. In particular, we explicitly demonstrate that the constructed quantity can vary as a tensor under the general coordinate transformation. Furthermore, we verify that the energy-momentum conservation is satisfied because one of the two indices of the energy-momentum tensor should be in the local Lorentz frame. It is also shown that the gravitational energy and the matter one cancel out in certain space-times.

关键词： Classical general relativity fundamental problems and general formalism cosmology classical black holes

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The Light Rays Analogue of a Static Black Hole

The Light Rays Analogue of a Static Black Hole

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International Conference on Numerical Analysis and Applied Mathematics (ICNAAM)

作者： Bittencourt, E. De Lorenci, V. A. Klippert, R. Novello, M. Salim, J. M. Inst Cosmol Relatividade Astrofis ICRA CBPF BR-22290180 Rio De Janeiro Brazil Univ Roma La Sapienza Dipartimento Fis I-00185 Rome Italy Univ Fed Itajuba Inst Fis & Quim BR-37500903 Itajuba Brazil Univ Fed Itajuba Inst Matemat & Comp BR-37500903 Itajuba Brazil

ISBN: (纸本)9780735412873

The propagation of light pulses inside nonlinear static media is described in the limit of geometrical optics. A spherically symmetric dielectric model for a nonlinear medium at rest is obtained, with the help of which an exact analogue model of static black holes can be built. Such an optical model may improve the feasibility in laboratory of the null geodesics near a compact object with an observable gravitational Schwarzschild radius.

关键词： fundamental problems and general formalism Classical general relativity

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Dark galactic halos without dark matter

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EPL 2015年第5期109卷

作者： Nesbet, R. K. IBM Almaden Res Ctr San Jose CA 95120 USA

Using standard Einstein theory, baryonic mass cannot account for observed galactic rotation velocities and gravitational lensing, attributed to galactic dark-matter halos. In contrast, theory constrained by Weyl conformal scaling symmetry explains observed galactic rotation in the halo region without invoking dark matter. An explanation of dark halos, gravitational lensing, and structural stabilization, without dark matter and consistent with conformal theory, is proposed here. Condensation of uniform primordial matter into a material cloud or galaxy vacates a large surrounding spherical halo. Within such an extended vacancy in the original cosmic background mass-energy density, conformal theory predicts centripetal acceleration of the observed magnitude. Copyright (C) EPLA, 2015

关键词： Galactic halos Cosmology fundamental problems and general formalism

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Timescale for trans-Planckian collisions in Kerr spacetime

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EPL 2015年第3期110卷

作者： Patil, Mandar Joshi, Pankaj S. Nakao, Ken-ichi Kimura, Masashi Harada, Tomohiro Inter Univ Ctr Astron & Astrophys Pune 411007 Maharashtra India Rikkyo Univ Dept Phys Toshima Ku Tokyo 1718501 Japan Tata Inst Fundamental Res Bombay 400005 Maharashtra India Osaka City Univ Grad Sch Sci Dept Math & Phys Osaka 5588585 Japan Univ Cambridge Ctr Math Sci DAMTP Cambridge CB3 0WA England

We make a critical comparison between ultra-high-energy particle collisions around an extremal Kerr black hole and that around an over-spinning Kerr singularity, mainly focusing on the issue of the timescale of collisions. We show that the time required for two massive particles with the proton mass or two massless particles of GeV energies to collide around the Kerr black hole with Planck energy is several orders of magnitude longer than the age of the Universe for astro-physically relevant masses of black holes, whereas time required in the over-spinning case is of the order of ten million years, which is much shorter than the age of the Universe. Thus, from the point of view of observation of Planck scale collisions, the over-spinning Kerr geometry, subject to their occurrence, has distinct advantage over their black-hole counterparts. Copyright (C) EPLA, 2015

关键词： Classical general relativity fundamental problems and general formalism Singularities and cosmic censorship

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Acceleration in de Sitter spacetimes

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EPL 2015年第4期109卷

作者： Cotaescu, Ion I. West Univ Timisoara RO-300223 Timisoara Romania

We propose a definition of uniform accelerated frames in de Sitter spacetimes applying the Nachtmann method of introducing coordinates using suitable point-dependent isometries. In order to recover the well-known Rindler approach in the flat limit, we require the transformation between the static frame and the accelerated one to depend continuously on acceleration, obtaining thus the natural generalization of the Rindler transformation to the de Sitter spacetimes of any dimensions. Copyright (C) EPLA, 2015

关键词： fundamental problems and general formalism Quantum fields in curved spacetime

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