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Varying fine-structure constant cosmography

C. J. A. P. Martins, F. P. S. A Ferreira, P. V. Marto

Cosmography is a phenomenological and relatively model-independent approach to cosmology, where physical quantities are expanded as a Taylor series in the cosmological redshift, or in related variables. Here we apply this methodology to constrain possible cosmological variations of the fine-structure constant, α. Two peculiarities of this case are the existence of high-redshift data, and the fact that one term in the series is directly and tightly constraint by local laboratory tests with atomic clocks. We use this atomic clock data, together with direct model-independent high-resolution astrophysical spectroscopy measurements of α up to redshift z ∼ 7 and additional model-dependent constraints on α from the cosmic microwave background and big bang nucleosynthesis, to place stringent (parts per million level) constraints on the first two terms in the α cosmographic series.

Cosmology; Cosmography; Varying fundamental constants; Fine-structure constant; Atomic clocks;

Physics Letters B
Volume 827
2022 April

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Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia