Nonsingular origin of the universe and the cosmological constant problem

We consider a nonsingular origin for the universe starting from an Einstein static universe in the framework of a theory which uses two volume elements √-gd ⁴x and Φd ⁴x, where Φ is a metric independent density, also curvature, curvature square terms, first order formalism and for scale invariance a dilaton field φ are considered in the action. In the Einstein frame we also add a cosmological term that parametrizes the zero point fluctuations. The resulting effective potential for the dilaton contains two flat regions, for φ → ∞ relevant for the nonsingular origin of the universe and φ → -∞, describing our present universe. Surprisingly, avoidance of singularities and stability as φ → ∞ imply a positive but small vacuum energy as φ → -∞. Zero vacuum energy density for the present universe is the "threshold" for universe creation.