The cosmological constant and entropy problems: mysteries of the present
  with profound roots in the past
  An accelerated universe should naturally have a vacuum energy density
determined by its dynamical curvature. The cosmological constant is most likely
a temporary description of a dynamical variable that has been drastically
evolving from the early inflationary era to the present. In this Essay we
propose a unified picture of the cosmic history implementing such an idea, in
which the cosmological constant problem is fixed at early times. All the main
stages, from inflation and its ("graceful") exit into a standard radiation
regime, as well as the matter and dark energy epochs, are accounted for.
Finally, we show that for a generic Grand Unified Theory associated to the
inflationary phase, the amount of entropy generated from primeval vacuum decay
can explain the huge measured value today.
