Tachyons, scalar fields, and cosmology

Vittorio Gorini, Alexander Kamenshchik, Ugo Moschella, and Vincent Pasquier
Phys. Rev. D 69, 123512 – Published 11 June 2004
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Abstract

We study the role that tachyon fields may play in cosmology as compared to the well-established use of minimally coupled scalar fields. We first elaborate on a kind of correspondence existing between tachyons and minimally coupled scalar fields; corresponding theories give rise to the same cosmological evolution for a particular choice of the initial conditions but not for any other. This leads us to study a specific one-parameter family of tachyonic models based on a perfect fluid mixed with a positive cosmological constant. For positive values of the parameter, one needs to modify Sen’s action and use the σ process of resolution of singularities. The physics described by this model is dramatically different and much richer than that of the corresponding scalar field. For particular choices of the initial conditions, the universe, which does mimic for a long time a de Sitter–like expansion, ends up in a finite time in a special type of singularity that we call a big brake. This singularity is characterized by an infinite deceleration.

  • Received 7 November 2003

DOI:https://doi.org/10.1103/PhysRevD.69.123512

©2004 American Physical Society

Authors & Affiliations

Vittorio Gorini

  • Dipartimento di Scienze Fisiche e Matematiche, Università dell’Insubria, Via Valleggio 11, 22100 Como, Italy
  • INFN, sez. di Milano, Via Caloria 16, 20133 Milano, Italy

Alexander Kamenshchik

  • Dipartimento di Scienze Fisiche e Matematiche, Università dell’Insubria, Via Valleggio 11, 22100 Como, Italy
  • L.D. Landau Institute for Theoretical Physics of the Russian Academy of Sciences, Kosygin str. 2, 119334 Moscow, Russia

Ugo Moschella

  • Dipartimento di Scienze Fisiche e Matematiche, Università dell’Insubria, Via Valleggio 11, 22100 Como, Italy
  • INFN, sez. di Milano, Via Caloria 16, 20133 Milano, Italy

Vincent Pasquier

  • Service de Physique Théorique, C.E. Saclay, 91191 Gif-sur-Yvette, France

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Vol. 69, Iss. 12 — 15 June 2004

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