• Nonsingular cosmological models: the massive scalar field case

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      https://www.ias.ac.in/article/fulltext/pram/030/01/0015-0027

    • Keywords

       

      Symmetry breaking; cosmology; nonsingular cosmological models

    • Abstract

       

      The nonminimal coupling of a massive self-interacting scalar field with a gravitational field is studied. Spontaneous symmetry breaking occurs in the open universe even when the sign on the mass term is positive. In contrast to grand unified theories, symmetry breakdown is more important for the early universe and it is restored only in the limit of an infinite expansion. Symmetry breakdown is shown to occur in flat and closed universes when the mass term carries a wrong sign. The model has a naturally defined effective gravitational coupling coefficient which is rendered time-dependent due to the novel symmetry breakdown. It changes sign below a critical value of the cosmic scale factor indicating the onset of a repulsive field. The presence of the mass term severely alters the behaviour of ordinary matter and radiation in the early universe. The total energy density becomes negative in a certain domain. These features make possible a nonsingular cosmological model for an open universe. The model is also free from the horizon and the flatness problems.

    • Author Affiliations

       

      B S Sathyaprakash1 K P Sinha1 2

      1. Department of Physics and Mathematical Sciences, Indian Institute of Science, Bangalore - 560012, India
      2. Division of Physics and Mathematical Sciences, Indian Institute of Science, Bangalore - 560012, India
    • Dates

       
  • Pramana – Journal of Physics | News

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      Posted on July 25, 2019

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