Inflation and Unification

Abstract

Two distinct classes of realistic inflationary models consistent with present observations are reviewed. The first example relies on the Coleman-Weinberg potential and is readily realized within the framework of spontaneously broken global symmetries (for instance, global U(1)_B-L). Depending on the parameters either new or large field inflation is possible. The second example exploits supersymmetry which makes implementation of inflation within local gauge theories much more accessible. An example based on spontaneously broken local U(1)_B-L is discussed. Leptogenesis is naturally realized in both cases.