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Entropy 2016, 18(2), 60;

Varying Constants Entropic-ΛCDM Cosmology

Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin, Poland
National Centre for Nuclear Research, Andrzeja Sołtana 7, 05-400 Otwock, Poland
Copernicus Center for Interdisciplinary Studies, Sławkowska 17, 31-016 Kraków, Poland
These authors contributed equally to this work.
Author to whom correspondence should be addressed.
Academic Editor: Remo Garattini
Received: 22 December 2015 / Revised: 26 January 2016 / Accepted: 27 January 2016 / Published: 22 February 2016
(This article belongs to the Special Issue Entropy in Quantum Gravity and Quantum Cosmology)
Full-Text   |   PDF [4271 KB, uploaded 23 February 2016]   |  


We formulate the basic framework of thermodynamical entropic force cosmology which allows variation of the gravitational constant G and the speed of light c. Three different approaches to the formulation of the field equations are presented. Some cosmological solutions for each framework are given and one of them is tested against combined observational data (supernovae, BAO, and CMB). From the fit of the data, it is found that the Hawking temperature numerical coefficient γ is two to four orders of magnitude less than usually assumed on the geometrical ground theoretical value of O(1) and that it is also compatible with zero. In addition, in the entropic scenario, we observationally test that the fit of the data is allowed for the speed of light c growing and the gravitational constant G diminishing during the evolution of the universe. We also obtain a bound on the variation of c to be Δc / c ∝ 10-5 > 0 , which is at least one order of magnitude weaker than the quasar spectra observational bound. View Full-Text
Keywords: varying constants; entropic force; gravitational thermodynamics varying constants; entropic force; gravitational thermodynamics

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Da̧browski, M.P.; Gohar, H.; Salzano, V. Varying Constants Entropic-ΛCDM Cosmology. Entropy 2016, 18, 60.

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