2003/07/31 by E. J. Copeland, Edmund J. Copeland, N. J. Nunes +1 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #Earth Systems and Cosmic Evolution #Solar and Space Plasma Dynamics #astro-ph #hep-ph
paper · pdf · doi:10.1103/physrevd.69.023501
published as Phys.Rev. D69 (2004) 023501 · 13 pages, 10 figures, RevTex, new references added
arxiv created 2003/09/04 · openalex publication_date 2004/01/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the change of the effective fine structure constant in the cosmological models of a scalar field with a nonvanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place empirical constraints on the size of the possible coupling and explore a large class of models that exhibit tracking behavior. The change of the fine structure constant implied by the quasar absorption spectra together with the requirement of tracking behavior impose a lower bound of the size of this coupling. Furthermore, the transition to the quintessence regime implies a narrow window for this coupling around 10^\ensuremath-5 in units of the inverse Planck mass. We also propose a nonminimal coupling between electromagnetism and quintessence which has the effect of leading only to changes of alpha determined from atomic physics phenomena, but leaving no observable consequences through nuclear physics effects. In doing so we are able to reconcile the claimed cosmological evidence for a changing fine structure constant with the tight constraints emerging from the Oklo natural nuclear reactor.