### Abstract

We study a dark energy scenario in the presence of a tachyon field φ with potential V(φ) and a barotropic perfect fluid. The cosmological dynamics crucially depends on the asymptotic behavior of the quantity λ = -M_{p}V_{φ}/V^{3/2}. die;/í3/É2. If λ is a constant, which corresponds to an inverse square potential V(φ) ∝ φ^{-2}, there exists one stable critical point that gives an acceleration of the Universe at late times. When λ → 0 asymptotically, we can have a viable dark energy scenario in which the system approaches an instantaneous critical point that dynamically changes with λ. If |λ| approaches infinity asymptotically, the Universe does not exhibit an acceleration at late times. In this case, however, we find an interesting possibility that a transient acceleration occurs in a regime where |λ| is smaller than of order unity.

Original language | English |
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Article number | 043003 |

Pages (from-to) | 043003-1-043003-11 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 71 |

Issue number | 4 |

DOIs | |

Publication status | Published - 2005 Feb |

Externally published | Yes |

### ASJC Scopus subject areas

- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)

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## Cite this

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,

*71*(4), 043003-1-043003-11. [043003]. https://doi.org/10.1103/PhysRevD.71.043003