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Related papers: Varying physical constants and the lithium problem

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Following a short discussion of some unresolved issues in the standard model of cosmology (considered to be a generic LCDM model with flat geometry and an early period of inflation), an update on the current state of research regarding the…

General Relativity and Quantum Cosmology · Physics 2025-07-28 J. C. Lindner

Currently, the standard cosmological model faces some tensions and discrepancies between observations at early and late cosmological time. One of them concerns the well-known $H_0$-tension problem, i.e., a $\sim4.4\sigma$-difference between…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-13 Jailson Alcaniz , Nicolás Bernal , Antonio Masiero , Farinaldo S. Queiroz

The effects of the cosmological constant on the static equilibrium configurations and stability against small radial perturbations of relativistic polytropic spheres are investigated. This study numerically solves the hydrostatic…

General Relativity and Quantum Cosmology · Physics 2020-04-15 José D. V. Arbañil , Pedro H. R. S. Moraes

We present an improved calculation of the light element abundances in the framework of Big Bang nucleosynthesis as a function of the Higgs vacuum expectation value $v$. We compare the methods of our calculation to previous literature…

High Energy Physics - Phenomenology · Physics 2024-06-18 Helen Meyer , Ulf-G. Meißner

We utilise a form for the Hubble parameter to generate a number of solutions to the Einstein field equations with variable cosmological constant and variable gravitational constant in the presence of a bulk viscous fluid. The Hubble law…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Anirudh Pradhan , Aotemshi I

The author proposed in his previous papers in 2001 that the problem of the cosmological constant could be resolved and its calculated value agrees excellently with the observations by assuming that the space-time itself, as the phase of…

General Physics · Physics 2007-05-23 H. M. Mok

We investigate the running cosmological constant model with dark energy linearly proportional to the Hubble parameter, $\Lambda = \sigma H + \Lambda_0$, in which the $\Lambda$CDM limit is recovered by taking $\sigma=0$. We derive the linear…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-22 Chao-Qiang Geng , Chung-Chi Lee , Kaituo Zhang

The conventional Big Bang model successfully anticipates the initial abundances of 2H(D), 3He, and 4He, aligning remarkably well with observational data. However, a persistent challenge arises in the case of 7Li, where the predicted…

Nuclear Theory · Physics 2024-04-25 C. A. Bertulani , Shubhchintak

We argue that the discrepancy between the Planck mass scale and the observed value of the cosmological constant can be largely attenuated if those quantities are understood as a result of effective, and thus scale-dependent, couplings. We…

General Relativity and Quantum Cosmology · Physics 2020-01-15 Felipe Canales , Benjamin Koch , Cristobal Laporte , Angel Rincon

The $\Lambda$CDM model provides a good fit to a large span of cosmological data but harbors areas of phenomenology. With the improvement of the number and the accuracy of observations, discrepancies among key cosmological parameters of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-14 Eleonora Di Valentino , Olga Mena , Supriya Pan , Luca Visinelli , Weiqiang Yang , Alessandro Melchiorri , David F. Mota , Adam G. Riess , Joseph Silk

We construct the cosmological model to explain the cosmological constant problem. We built the extension of the standard cosmological model $\Lambda$CDM by consideration of decaying vacuum energy represented by the running cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-08 Marek Szydlowski

Based on the assertion that the cosmological constant problem is essentially a quantum gravity problem, the framework which addresses the cosmological constant problem should also bear a picture for the ``quantum space-time''. In this talk…

High Energy Physics - Phenomenology · Physics 2009-10-07 M. M. Sheikh-Jabbari

The cosmological constant (vacuum energy) problem is analyzed within the scope of quantum theories with UV-cut-off or fundamental length. Various cases associated with the appearance of the latter are considered both using the Generalized…

General Relativity and Quantum Cosmology · Physics 2007-12-20 A. E. Shalyt-Margolin

Future cosmological surveys will probe the expansion history of the universe and constrain phenomenological models of dark energy. Such models do not address the fine-tuning problem of the vacuum energy, i.e. the cosmological constant…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-11 M. C. David Marsh

Associated with the cosmic acceleration are the old and new cosmological constant problems, recently put into the more general context of the dark energy problem. In broad terms, the old problem is related to an unexpected order of…

Astrophysics · Physics 2008-11-26 Mustapha Ishak

We have critically compared different approaches to the cosmological constant problem, which is at the edge of elementary particle physics and cosmology. This problem is deeply connected with the difficulties formulating a theory of quantum…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Stefan Nobbenhuis

We analyze the effect of variation of fundamental couplings and mass scales on primordial nucleosynthesis in a systematic way. The first step establishes the response of primordial element abundances to the variation of a large number of…

Astrophysics · Physics 2008-12-18 Thomas Dent , Steffen Stern , Christof Wetterich

Recently a notion of gravitational aether is advocated to solve the cosmological constant problem.Through the modification of the source of gravity one finds that the effective Newton's constant is source dependent so as to provide a simple…

General Relativity and Quantum Cosmology · Physics 2009-11-09 Xiao-Mei Kuang , Yi Ling

We review recent work on the possibility of a varying speed of light (VSL). We start by discussing the physical meaning of a varying $c$, dispelling the myth that the constancy of $c$ is a matter of logical consistency. We then summarize…

Astrophysics · Physics 2008-11-26 Joao Magueijo

We extend the usual gravitational action principle by promoting the bare cosmological constant (CC) from a parameter to a field which can take many possible values. Variation leads to a new integral constraint equation which determines the…

General Relativity and Quantum Cosmology · Physics 2011-03-21 John D. Barrow , Douglas J. Shaw
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