The inflationary Universe

According to the inflationary Universe scenario the Universe in the very early stages of its evolution was exponentially expanding in the unstable vacuumlike state. At the end of the exponential expansions (inflation) the energy of the unstable vacuum (of a classical scalar field) transforms into the energy of hot dense matter, and the subsequent evolution of the Universe is described by the usual hot Universe theory. Recently it was realised that the exponential expansion during the very early stages of evolution of the Universe naturally occurs in a wide class of realistic theories of elementary particles. The inflationary Universe scenario makes it possible to obtain a simple solution to many long-standing cosmological problems and leads to a crucial modification of the standard point of view of the large-scale structure of the Universe.