  Slow-roll inflation can be studied as an effective field theory. The form of
the inflaton potential consistent with the data is V(phi) = N M^4
w(phi/[sqrt{N} M_{Pl}]) where phi is the inflaton field, M is the inflation
energy scale, and N ~ 50 the number of efolds. The dimensionless function
w(chi) and field chi are O(1). This form of the potential encodes the slow-roll
expansion as an expansion in 1/N.A The Hubble parameter, inflaton mass and
non-linear couplings are of the see-saw form in terms of M/M_{Pl}. The quartic
coupling is lambda~1/N (M/M_{Pl})^4. The smallness of the non-linear couplings
is not a result of fine tuning but a natural consequence of the validity of the
effective field theory and slow roll approximation. Quantum corrections to slow
roll inflation are computed and turn to be an expansion in powers (H/M_{Pl})^2.
The corrections to the inflaton effective potential and its equation of motion
are computed, as well as the quantum corrections to the observable power
spectra. The near scale invariance of the fluctuations introduces a strong
infrared behavior naturally regularized by Delta=(n_s -1)/2+r/8. We consider
scalar curvature and tensor perturbations as well as light scalars and Dirac
fermions coupled to the inflaton.The subhorizon part is completely specified by
the trace anomaly of the fields with different spins and is solely determined
by the space-time geometry. This inflationary effective potential is strikingly
different from the usual Minkowski space-time result.Quantum corrections to the
power spectra are expressed in terms of the CMB observables. Trace anomalies
(especially the graviton part) dominate these quantum corrections in a definite
direction: they enhance the scalar curvature fluctuations and reduce the tensor
fluctuations.
