We study cosmological dynamics of a multi-field system for a general Lagrangian density having scaling solutions. This allows the possibility that scaling radiation and matter eras are followed by a late-time cosmic acceleration through an assisted inflation mechanism. Using the bound coming from Big-Bang-Nucleosynthesis (BBN) and the condition under which each field cannot drive inflation as a single component of the universe, we find the following features: (i) a transient or eternal cosmic acceleration can be realized after the scaling matter era, (ii) a "thawing" property of assisting scalar fields is crucial to determine the evolution of the field equation of state wφ, and (iii) the field equation of state today can be consistent with the observational bound wφin the presence of multiple scalar fields.
|出版ステータス||Published - 2009|
|イベント||19th Workshop on General Relativity and Gravitation in Japan, JGRG 2009 - Tokyo, Japan|
継続期間: 2009 11月 30 → 2009 12月 4
|Conference||19th Workshop on General Relativity and Gravitation in Japan, JGRG 2009|
|Period||09/11/30 → 09/12/4|
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