2004/05/31 by Federico Piazza, Shinji Tsujikawa · 18 citations
Physics and Astronomy · #Cosmological constant #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark energy #Dark fluid #Dark matter #Dilaton #Energy condition #Lambda-CDM model #Particle physics theoretical and experimental studies #Scalar field #Scalar field dark matter #Vacuum energy #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2004/07/004
published as JCAP 0407 (2004) 004 · 26 pages, 6 figures
openalex publication_date 2004/07/14 · arxiv created 2004/07/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We explore a dark energy model with a ghost scalar field in the context of the runaway dilaton scenario in low-energy effective string theory. We address the problem of vacuum stability by implementing higher-order derivative terms and show that a cosmologically viable model of ‘phantomized’ dark energy can be constructed without violating the stability of quantum fluctuations. We also analytically derive the condition under which cosmological scaling solutions exist, starting from a general Lagrangian including the phantom type scalar field. We apply this method to the case where the dilaton is coupled to non-relativistic dark matter and find that the system tends to become quantum mechanically unstable when a constant coupling is always present. Nevertheless, it is possible to obtain a viable cosmological solution in which the energy density of the dilaton eventually approaches the present value of dark energy provided that the coupling rapidly grows during the transition to the scalar field dominated era.