THE PRIMORDIAL PERTURBATION SPECTRUM

by Alexei Starobinsky (Landau Institute for Theoretical Physics, Moscow)

Thursday 18 Aug 2005, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

Primordial scalar (density) perturbations and gravitational waves are the main observable quantities which remained from very early stages of evolution of our Universe. Observational data show that the Fourier power spectrum of density perturbations is very close to the flat (i.e., the Harrison-Zeldovich) one and their statistics is Gaussian, in agreement with predictions of the simplest versions of the inflationary scenario of the early Universe. However, some small deviations from the flat spectrum and the Gaussian statistics are expected generically. I review recent results on the primordial perturbation spectrum including a new general expression for the spectrum of adiabatic perturbations unifying different ways of their generation both during and after inflation, as well as an exact solution for an inflaton field potential producing the exactly flat adiabatic spectrum. Also, it will be shown how to obtain a correct rms value of inflaton field fluctuations from the formalism of stochastic inflation.