Qualitative Analysis of Brans–Dicke Universes with a Cosmological Constant

✍ Scribed by Shawn J. Kolitch

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 467 KB
• Volume: 246
• Category: Article
• ISSN: 0003-4916
• DOI: 10.1006/aphy.1996.0022

✦ Synopsis

Solutions to flat space Friedmann Robertson Walker cosmologies in Brans Dicke theory with a cosmological constant are investigated. The matter is modeled as a #-law perfect fluid. The field equations are reduced from fourth order to second order through a change of variables, and the resulting two-dimensional system is analyzed using dynamical system theory. When the Brans Dicke coupling constant is positive (|>0), all initially expanding models approach exponential expansion at late times, regardless of the type of matter present. If |<0, then a wide variety of qualitatively distinct models are present, including nonsingular bounce'' universes, vacillating'' universes, and, in the special case of |= &1, models which approach stable Minkowski spacetime with an exponentially increasing scalar field at late times. Since power-law solutions do not exist, none of the models appears to offer any advantage over the standard deSitter solution of general relativity in achieving a graceful exit from inflation.