The anomaly-induced effective action and the possibility of a natural inflation from vacuum quantum effects

By Ilya Shapiro, Universidade Federal de Juiz de Fora

Our purpose is to investigate the possible impact of quantum effects of vacuum to the early history of the Universe. In the framework of effective field theory, some reasonable assumptions about the particle content at the energies below the Planck scale favor a natural inflation. In particular, the existence of supersymmetry at high energies together with the supersymmetry breaking at low energies provide the possibility of inflationary scenario which is based on the principles and results of quantum field theory. The important part is the decoupling of the massive S-particles and the sufficient universality of the vacuum effective action, which we tried to check explicitly. This inflationary model does not need a special scalar (e.g. inflaton) and does not require, up to our present knowledge, a fine tuning of any sort. The model predicts an enormous number of the inflationary e-folds, while the amplitude of the gravitational waves almost does not grow up during the last 65 e-folds and their spectrum is very close to the flat one, in agreement with the existing CMB data.