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Related papers: Varying Fine Structure Constant and Black Hole Phy…

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Last year I talked at this meeting about a possible time dependence of the QCD coupling constant $\alpha_s$. This year I shall look into the problem once more, without fully repeating the arguments given last year. Astrophysical indications…

High Energy Physics - Phenomenology · Physics 2009-11-10 Harald Fritzsch

In this paper, we investigate nonlinearly charged AdS black holes in four-dimensional critical gravity and study more exact black hole thermodynamics under the effect of small statistical fluctuations. We compute the correction to the…

General Relativity and Quantum Cosmology · Physics 2023-07-10 Prosenjit Paul , Sudhaker Upadhyay , Yerlan Myrzakulov , Dharm Veer Singh , Kairat Myrzakulov

We study evolution and thermodynamics of a slow-roll transition between early and late time de Sitter phases, both in the homogeneous case and in the presence of a black hole, in a scalar field model with a generic potential having both a…

High Energy Physics - Theory · Physics 2017-11-22 Ruth Gregory , David Kastor , Jennie Traschen

The existing observational data on possible variations of fundamental physical constants (FPC) confirm more or less confidently only a variability of the fine structure constant $\alpha$ in space and time. A model construction method is…

General Relativity and Quantum Cosmology · Physics 2015-06-12 K. A. Bronnikov , V. N. Melnikov , S. G. Rubin , I. V. Svadkovsky

We present a class of models in which the coupling of the photon to an ultralight scalar field that has a time-dependent vacuum expectation value causes the fine structure constant to oscillate in time. The scalar field is assumed to…

High Energy Physics - Phenomenology · Physics 2022-09-07 Dawid Brzeminski , Zackaria Chacko , Abhish Dev , Anson Hook

We determine the behaviour of a time-varying fine structure 'constant' $\alpha (t)$ during the early and late phases of universes dominated by the kinetic energy of changing $\alpha (t)$, radiation, dust, curvature, and lambda,…

Astrophysics · Physics 2008-11-26 J. D. Barrow , H. B. Sandvik , J. Magueijo

We evaluate the full time dependence of holographic complexity in various eternal black hole backgrounds using both the complexity=action (CA) and the complexity=volume (CV) conjectures. We conclude using the CV conjecture that the rate of…

High Energy Physics - Theory · Physics 2018-11-15 Dean Carmi , Shira Chapman , Hugo Marrochio , Robert C. Myers , Sotaro Sugishita

There are obvious discrepancies among various experimental constraints on the variation of the fine-structure constant, $\alpha$. We attempt to discuss the issue in the framework of de Sitter invariant Special Relativity (${\cal SR}_{c,R}$)…

Astrophysics · Physics 2015-06-24 Shao-Xia Chen , Neng-Chao Xiao , Mu-Lin Yan

The recent measurements of the Cosmic Microwave Background anisotropies at arcminute angular scales performed by the ACT and SPT experiments are probing the damping regime of CMB fluctuations. The analysis of these datasets unexpectedly…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Eloisa Menegoni , Maria Archidiacono , Erminia Calabrese , Silvia Galli , C. J. A. P. Martins , Alessandro Melchiorri

By integration of generalized BSBM and Brans-Dicke cosmological models, in this article, we investigate the theoretical framework of fine structure constant variation and current cosmic acceleration. We first develop a mathematical…

General Relativity and Quantum Cosmology · Physics 2015-06-11 H. Farajollahi , A. Salehi

Is the recent evidence for a time-varying fine structure 'constant' $\alpha$ to be interpreted as a varying $e$, $c$, $\hbar$, or a combination thereof? We consider the simplest varying electric charge and varying speed of light theories…

Astrophysics · Physics 2009-11-07 Joao Magueijo , John D. Barrow , Haavard Bunes Sandvik

A theory of 3-space explains the phenomenon of gravity as arising from the time-dependence and inhomogeneity of the differential flow of this 3-space. The emergent theory of gravity has two gravitational constants: G - Newton's constant,…

General Physics · Physics 2007-05-23 Reginald T. Cahill

Gravitational anomalies such as the mine/borehole g anomaly, the near-flatness of the spiral galaxy rotation-velocity curves, currently interpreted as a `dark matter' effect, the absence of that effect in ordinary elliptical galaxies, and…

General Physics · Physics 2007-05-23 Reginald T. Cahill

We review properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that are…

Astrophysics · Physics 2009-11-13 John D. Barrow

We examine the variation of the fine structure constant in the context of a two-field quintessence model. We find that, for solutions that lead to a transient late period of accelerated expansion, it is possible to fit the data arising from…

Astrophysics · Physics 2009-11-10 M. C. Bento , O. Bertolami , N. M. C. Santos

We examine the thermodynamics of a regular charged black hole (RCB) added with corrections due to massive gravity and thermal fluctuations at quantum level. We then derive the expressions for all the relevant thermodynamic quantities such…

General Relativity and Quantum Cosmology · Physics 2022-07-05 Amruta Desai , Shubham Sharma , Prince A. Ganai

We review properties of cosmological theories for the variation of the fine structure 'constant'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that are…

General Relativity and Quantum Cosmology · Physics 2012-12-11 John D. Barrow

Interpreting the cosmological constant as a pressure, whose thermodynamically conjugate variable is a volume, modifies the first law of black hole thermodynamics. Properties of the resulting thermodynamic volume are investigated: the…

General Relativity and Quantum Cosmology · Physics 2012-03-07 Brian P. Dolan

We study thermodynamic quantities of an acoustic black hole and its thermodynamic stability in a cavity based on the generalized uncertainty principle. It can be shown that there is a minimal black hole which can be a stable remnant after…

General Relativity and Quantum Cosmology · Physics 2008-01-10 Wontae Kim , Edwin J. Son , Myungseok Yoon

We investigate the weak cosmic censorship conjecture in charged anti-de Sitter black holes with thermodynamic pressure and volume by the scattering of the charged scalar field in four and higher dimensions. We assume that the internal…

General Relativity and Quantum Cosmology · Physics 2019-08-20 Bogeun Gwak
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