Particle creation in the early Universe: Achievements and problems

Abstract

Results on particle creation from vacuum by the gravitational field of the expanding Friedmann Universe are presented. Finite results for the density of particles and the energy density for created particles are given for different exact solutions and different expansion modes of the Universe. The results are obtained for both conformal and nonconformal particles. The hypothesis on the origin of visible matter from the decay of created from vacuum superheavy particles identified with dark matter is discussed.