2001/09/24 by John D. Barrow, J. D. Barrow, H. B. Sandvik +2 · 11 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.65.063504
published as Phys.Rev.D65:063504,2002 · 9 pages, 4 figures, Submitted to PRD
arxiv created 2001/09/24 · openalex publication_date 2002/02/21 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We determine the behavior of a time-varying fine structure ``constant'' \ensuremathα(t) during the early and late phases of universes dominated by the kinetic energy of changing \ensuremathα(t), radiation, dust, curvature, and lambda, respectively. We show that after leaving an initial vacuum-dominated phase during which \ensuremathα increases, \ensuremathα remains constant in universes such as our own during the radiation era, and then increases slowly, proportional to a logarithm of cosmic time, during the dust era. If the universe becomes dominated by a negative curvature or a positive cosmological constant then \ensuremathα tends rapidly to a constant value. The effect of an early period of de Sitter or power-law inflation is to drive \ensuremathα to a constant value. Various cosmological consequences of these results are discussed with reference to recent observational studies of the value of \ensuremathα from quasar absorption spectra and to the existence of life in expanding universes.