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Universe 2015, 1(1), 6-16;

Observational Constraints on Varying-Alpha Domain Walls

Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal
Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, PT4169-007 Porto, Portugal
Author to whom correspondence should be addressed.
Academic Editor: Lorenzo Iorio
Received: 15 October 2014 / Revised: 20 November 2014 / Accepted: 28 January 2015 / Published: 5 February 2015
Full-Text   |   PDF [217 KB, uploaded 5 February 2015]


We consider the possibility that current hints of spatial variations of the fine structure constant at high redshift, based on VLT/UVES and Keck/HIRES observations, could be caused by a biased domain wall network described by a scalar field non-minimally coupled to the electromagnetic field. We show that in order to be responsible for the reported spatial variations of the fine structure constant, the fractional contribution of the domain wall network to the energy density of the Universe should be tightly constrained within the range \(10^{-10} < \Omega_{w0} < 10^{-5}\). We also show that the domain wall dynamics should be essentially frictionless, so that its characteristic scale is in the order of the Hubble radius at the present time. View Full-Text
Keywords: cosmology; topological defects; domain walls; fundamental constants cosmology; topological defects; domain walls; fundamental constants
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Avelino, P.P.; Sousa, L. Observational Constraints on Varying-Alpha Domain Walls. Universe 2015, 1, 6-16.

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