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3.1. The potential dominated state

Consider adding an additional scalar matter field phi (the ``inflaton'') to the cosmological model. In general the stress-energy tensor of this field will depend on the space and time derivatives of the field as well as the potential V(phi). In the limit where the potential term dominates over the derivative terms the stress-energy tensor of phi takes the form

Equation 7 (7)

which leads (by comparison with Eqn. 3) to rho = -p = V.

Solving Eqn. 2 gives rho(a) = V. Because we are assuming phidot is negligible we also have V = const.. Under these circumstances H = const. and the Friedmann equation gives exponential expansion:

Equation 8 (8)

very different from the power law behavior in the SBB.