2001/10/31 by John D. Barrow, J. D. Barrow, H. B. Sandvik +2 · 1 citation
Mathematics · Physics and Astronomy · #Anthropic principle #Astrophysics #Black Holes and Theoretical Physics #Computer science #Constant (computer programming) #Cosmological constant #Cosmology #Cosmology and Gravitation Theories #Curvature #Flatness (cosmology) #Geometry #Lambda #Mathematical physics #Mathematics #Metric expansion of space #Physics #Programming language #Quantum mechanics #Relativity and Gravitational Theory #Scalar curvature #Theoretical physics #Universe #astro-ph #gr-qc #hep-th #physics.pop-ph
paper · pdf · doi:10.1103/physrevd.65.123501
published as Phys.Rev. D65 (2002) 123501 · 7 pages, 5 figures, Corrected sign error and made necessary modifications. This version is accepted for publication in Phys.Rev.D
arxiv created 2002/04/05 · openalex publication_date 2002/05/20 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In some cosmological theories with varying constants there are anthropic reasons why the expansion of the universe must not be too close to flatness or the cosmological constant too close to zero. Using exact theories which incorporate time variations in \ensuremathα and in G we show how the presence of negative spatial curvature and a positive cosmological constant play an essential role in bringing to an end variations in the scalar fields that drive time changes in these ``constants'' during any dust-dominated era of a universe's expansion. In spatially flat universes with \ensuremathΛ=0 the fine structure constant grows to a value which makes the existence of atoms impossible.