2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/207814We study the production of gravitinos during the preheating era after inflation by means of the non-perturbative Bogolyubov technique. Considering only the helicity $\pm 3/2$ states, the problem is reduced to the simpler Dirac fermions case. We calculate the production in a particular supergravity model in an expanding universe and obtain the spectrum and number density. Finally we compare the results with the nucleosynthesis bounds and extract some consequences.10 pages, LaTeX, 2 figures. Talk given in the International Workshop on Particles in Astrophysics and Cosmology, Valencia (Spain), May 3-8, 1999High Energy Physics - PhenomenologyAstrophysicsHigh Energy Physics - Theorytext