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Centro de Astrofísica da Universidade do Porto

Cosmological evolution of α and μ and the dynamics of dark energy

P. P. Avelino

Abstract
We study the cosmological evolution of the fine structure constant α and the proton-to-electron mass ratio μ=mp/me in the context of a generic class of models, where the gauge kinetic function is a linear function of a quintessence-type real scalar field ϕ described by a Lagrangian with a standard kinetic term and a scalar field potential V(ϕ) . We further assume that the scalar field potential is a monotonic function of ϕ and that the scalar field is always rolling down the potential. We show that, for this class of models, low-redshift constraints on the evolution of α and μ can provide very stringent limits on the corresponding variations at high redshift. We also demonstrate that these limits may be relaxed by considering more general models for the dynamics of α and μ . However, in this case, the ability to reconstruct the evolution of the dark energy equation of state using varying couplings could be seriously compromised.

Physical Review D
Volume 78, Page 043516
August 2008

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Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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