English
Related papers

Related papers: Do $\Lambda_{CC}$ and $G$ run?

200 papers

A mechanism for suppressing the cosmological constant is developed, based on an analogy with a superconducting phaseshift in which free fermions coupled perturbatively to a weak gravitational field are in an unstable false vacuum state. The…

High Energy Physics - Theory · Physics 2007-05-23 Stephon Alexander , Manasse Mbonye , John Moffat

The problem of determining the effects of the surrounding plasma on nuclear reaction rates in stars is formulated ab initio, using the techniques of quantum statistical mechanics. We derive a result that expresses the complete effects of…

Astrophysics · Physics 2008-11-26 Lowell S. Brown , R. F. Sawyer

After reviewing the modified Newtonian dynamics (MOND) proposal, we advocate that the associated phenomenology may actually not result from a modification of Newtonian gravity, but from a mechanism of "gravitational polarization" of some…

Astrophysics · Physics 2008-07-09 Luc Blanchet , Alexandre Le Tiec

We argue that the instability of Euclidean Einstein gravity is an indication that the vacuum is non perturbative and contains a condensate of the metric tensor in a manner reminiscent of Yang-Mills theories. As a simple step toward the…

High Energy Physics - Theory · Physics 2009-11-10 Janos Polonyi , Eniko Regos

In absence of matter Einstein gravity with a cosmological constant $\La$ can be formulated as a scale-free theory depending only on the dimensionless coupling constant G \Lambda where G is Newton constant. We derive the conformal field…

High Energy Physics - Theory · Physics 2009-11-11 Mariano Cadoni

On the basis of Hamilton a formalism the dynamic equations of movement scalar charged particles in a classical scalar field are formulated. Unlike earlier published works of the author the model with zero own weight of particles is…

General Relativity and Quantum Cosmology · Physics 2013-07-09 Yu. G. Ignat'ev

In this paper, the cosmological "constant" and the Hubble parameter are considered in the Weyl theory of gravity, by taking them as functions of $r$ and $t$, respectively. Based on this theory and in the linear approximation, we obtain the…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Mohammad Reza Tanhayi , Mohsen Fathi , Mohammad Vahid Takook

Keeping in mind the current picture of an accelerating and flat Universe, some specific dynamical models of the cosmological term $\Lambda$ have been selected for investigating the nature of dark energy. Connecting the free parameters of…

Astrophysics · Physics 2008-11-26 Saibal Ray , Utpal Mukhopadhyay , Xin-He Meng

We critically review several recent approaches to solving the two cosmological constant problems. The "old" problem is the discrepancy between the observed value of $\Lambda$ and the large values suggested by particle physics models. The…

High Energy Physics - Theory · Physics 2009-10-31 J. Garriga , A. Vilenkin

In this paper we continue the investigations in \cite{1} concerning the origin of the cosmological constant. First of all, we generalise the results in \cite{1,2} by considering a continuum approximation for a radiation field in a…

General Relativity and Quantum Cosmology · Physics 2019-08-23 Stefano Viaggiu

The cosmological constant ($\Lambda$), i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However,…

Astrophysics · Physics 2007-05-23 J. S. Alcaniz , H. Stefancic

The first and second laws of thermodynamics should lead to a consistent scenario for discussing the cosmological constant problem. In the present study, to establish such a thermodynamic scenario, cosmological equations in a flat…

General Relativity and Quantum Cosmology · Physics 2025-06-05 Nobuyoshi Komatsu

We present the results of two empirical constancies: the fine structure constant and the Rydberg constant. When the speed of light c is taken away from the fine structure constant, as shown elsewhere, this constancy implies the constancy of…

General Physics · Physics 2009-09-30 Antonio Alfonso-Faus

A cosmological constant, Lambda, is the most natural candidate to explain the origin of the dark energy (DE) component in the Universe. However, due to experimental evidence that the equation of state (EOS) of the DE could be evolving with…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Joan Sola , Hrvoje Stefancic

Massive spin 2 theories in flat or cosmological ($\Lambda \ne 0$) backgrounds are subject to discontinuities as the masses tend to zero. We show and explain physically why their Newtonian limits do not inherit this behaviour. On the other…

General Relativity and Quantum Cosmology · Physics 2010-04-06 S. Deser , Bayram Tekin

In classical gravity deviations from the predictions of the Einstein theory are often discussed within the framework of the conformal Newtonian gauge, where scalar perturbations are described by two potentials $\phi$ and $\psi$. In this…

General Relativity and Quantum Cosmology · Physics 2013-01-07 Herbert W. Hamber , Reiko Toriumi

We propose a revised formulation of General Relativity for cosmological settings, in which the Einstein constant varies with the energy density of the Universe. We demonstrate that this modification has only phenomenological impact of…

General Relativity and Quantum Cosmology · Physics 2025-08-28 Giovanni Montani , Giulia Maniccia , Elisa Fazzari , Alessandro Melchiorri

Contrary to popular mythology, Einstein did not invent the cosmological constant just in order construct his model universe. He discussed it earlier in "The Foundations of General Relativity" in connection with the proper structure of the…

History and Philosophy of Physics · Physics 2012-12-05 Alex Harvey

We provide a consistency relation between cosmological observables in general relativity with the cosmological constant. Breaking of this relation at any redshift would imply the breakdown of the hypothesis of the cosmological constant as…

Astrophysics · Physics 2009-06-23 Takeshi Chiba , Takashi Nakamura

We put forward a multi-time theory, in frame of which the cosmic acceleration is a natural phenomenon without cosmological constant or anything like that. The main point of this theory is that each of the gravity interaction and…

General Relativity and Quantum Cosmology · Physics 2010-04-16 Hongsheng Zhang