Low-scale quintessential inflation

In the quintessential inflationary model, the same master field that drives inflation becomes, later on, the dynamical source of the (present) accelerated expansion. Quintessential inflationary models require a curvature scale at the end of inflation around 10(-6)M(P) in order to explain the large scale fluctuations observed in the microwave sky. If the curvature scale at the end of inflation is much smaller than 10(-6)M(P), the large scale adiabatic mode may be produced thanks to the relaxation of a scalar degree of freedom, which will be generically denoted, according to the recent terminology, as the curvaton field. The production of the adiabatic mode is analyzed in detail in the case of the minimal quintessential inflationary model originally proposed by Peebles and Vilenkin.