Inflation

TheInflation modern cosmology introduces a brief “episode” of inflation into the development of the universe to solve fundamental problems of the “classical” Big Bang model. The very early phase of the exponential expansion of the universe is supposed to have taken place during the GUT time. Particularly exciting at the moment is the question of whether the quite speculative model of inflation, which can solve many fundamental problems of cosmology, is supported not only by theory but also by observations. This chapter provides a brief overview of the new developments, as far as they concern homogeneous cosmology. Quantum fluctuations around a classical inflaton field are addressed in Chap. 15.