Marco Bruni                                  GGI Florence, October 2006
Motivations for a quadratic EoS
§Why quadratic, P=Po + ar + e r /rc ?
simplest non-linear EoS, introduces energy scale(s);
Mostly in general, energy scale -> effective cosmological constant rL;
qualitative dynamics is representative of more general non-linear EoSÕs;
Parametrizes a vast class of DE models: truncated Taylor expansion of any  P(r) (3 parameters);
explore singularities and bounces or cyclic solutions (brane and pre-big bang inspired).

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