Cosmological perturbations in singularity-free, deflationary models

We consider scalar perturbations of energy-density for a class of cosmological models where an early phase of accelerated expansion evolves, without any fine-tuning for graceful exit, towards the standard Friedman eras of observed universe. The quantum-geometric procedure which generates such models agrees with results for string cosmology since it works if dynamics is dominated by a primordial fluid of extended massive objects. The main result is that characteristic scales of cosmological interest, connected with the extension of such early objects, are selected. © Società Italiana di Fisica.