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It is argued that when the dimension of space is a constant integer the full set of Einstein's field equations has more information than the spatial components of Einstein's equation plus the energy conservation law. Applying the former…

General Relativity and Quantum Cosmology · Physics 2015-06-25 J. A. S. Lima , M. Mohazzab

In the light of recent developments in Dark Energy, we consider the electron in a such a background field and show that at the Compton wavelength the electron is stable, in that the Cassini inward pressure exactly counterbalances the…

General Physics · Physics 2009-07-24 Burra G. Sidharth

We propose a model describing Einstein gravity coupled to a scalar field with an exponential potential. We show that the weak-field limit of the model has static solutions given by a gravitational potential behaving for large distances as…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Mariano Cadoni

We study the quantum backreaction from inflationary fluctuations of a very light, non-minimally coupled spectator scalar and show that it is a viable candiate for dark energy. The problem is solved by suitably adapting the formalism of…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-18 Dražen Glavan , Tomislav Prokopec , Alexei A. Starobinsky

The trace-free version of the Einstein Gravitational equations, essentially equivalent to unimodular gravity, can solve the troubling issue of the huge discrepancy between quantum field theory estimates of the vacuum energy density and the…

General Relativity and Quantum Cosmology · Physics 2014-12-31 George F R Ellis

We review and extend a novel approach that we introduced recently, to describe general dark energy or scalar-tensor models. Our approach relies on an ADM formulation based on the hypersurfaces where the underlying scalar field is uniform.…

High Energy Physics - Theory · Physics 2015-06-23 Jérôme Gleyzes , David Langlois , Filippo Vernizzi

It has recently been proposed by Mersini et al. 01, Bastero-Gil and Mersini 02 that the dark energy could be attributed to the cosmological properties of a scalar field with a non-standard dispersion relation that decreases exponentially at…

High Energy Physics - Theory · Physics 2009-11-07 Martin Lemoine , Jerome Martin , Jean-Philippe Uzan

We construct a model of dark energy with a technically natural small contribution to cosmic acceleration, i.e. this contribution does not receive corrections from other scales in the theory. The proposed acceleration mechanism appears…

High Energy Physics - Theory · Physics 2012-09-04 D. Blas , S. Sibiryakov

We present a pedagogical review of old inconsistencies of Classical Electrodynamics and of some new ideas that solve them. Problems with the electron equation of motion and with the non-integrable singularity of its self-field energy tensor…

High Energy Physics - Theory · Physics 2008-02-03 Manoelito M. de Souza

We study evolution of perturbations in dark matter and dark energy for spherical collapse. We study Tachyon models of dark energy using the approach outlined in Rajvanshi and Bagla (2018). We work with models that are allowed by current…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-13 Manvendra Pratap Rajvanshi , J. S. Bagla

A review of the new of the problem of dark energy using modified gravity approach is considered. An explanation of the difficulties facing modern cosmology is given and different approaches are presented. We show why some models of gravity…

General Relativity and Quantum Cosmology · Physics 2014-06-18 Ahmed Alhamzawi , Rahim Alhamzawi

We examine the effectiveness of the weak gravity conjecture in constraining the dark energy by comparing with observations. For general dark energy models with plausible phenomenological interactions between dark sectors, we find that…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-24 Ximing Chen , Bin Wang , Nana Pan , Yungui Gong

In the context of thermodynamics we discuss the way inevitable emerge an interaction between dark components, and in this way, provide a mechanism to understand the limits of the LCDM model and the class of interaction models between dark…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-22 Víctor H. Cárdenas , Daniela Grandón , Samuel Lepe

We revisit the theory of background fields constructed on the BRST-algebra of a spinning particle with $\mathcal{N}=4$ worldline supersymmetry, whose spectrum contains the graviton but no other fields. On a generic background, the closure…

High Energy Physics - Theory · Physics 2022-03-14 Daniel Bockisch , Ivo Sachs

A simple gravitational model with torsion is studied, and it is suggested that it could explain the dark matter and dark energy in the universe. It can be reinterpreted as a model using the Einstein gravitational equations where spacetime…

General Relativity and Quantum Cosmology · Physics 2022-03-28 Graeme W. Milton

As a companion work to [1], this Note presents a series of simple formulae and explicit results that illustrate and highlight why classical variational phase-field models cannot possibly predict fracture nucleation in elastic brittle…

Materials Science · Physics 2024-11-22 Farhad Kamarei , John E. Dolbow , Oscar Lopez-Pamies

A model of cosmology, that arises from the hypothesis that ordinary matter, dark matter and dark energy are made of the same stuff, is studied. It is argued that this hypothesis is a consequence of considering space and time in the same…

Astrophysics · Physics 2007-05-23 Isaac Cohen

In our comment we show that some of the very difficult problems have been successfully solved. We have to focus on the resolved problems, since the authors claims: Our hope, however, is that the topics we have presented will provide…

Strongly Correlated Electrons · Physics 2025-12-23 V. R. Shaginyan , A. Z. Msezane

We demonstrate that if k-essence can solve the coincidence problem and play the role of dark energy in the universe, the fluctuations of the field have to propagate superluminally at some stage. We argue that this implies that successful…

Astrophysics · Physics 2009-11-11 Camille Bonvin , Chiara Caprini , Ruth Durrer

By way of a complete integration of the Friedmann equations, in terms of observables, it is shown that for the cosmological constant $\Lambda > 0$ there exist non-flat FLRW models for which the total density parameter $\Omega$ remains $\sim…

Astrophysics · Physics 2009-11-10 Kayll Lake
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