Physics and Astronomy Calendar

I will review some aspects of inflationary physics. Inflation
is responsible for producing the ``clean'' homogeneous and isotropic
universe we live in, starting from rather generic initial conditions.
While inflation is very efficient in erasing any information on the
initial state, some trace may have remained on the largest observable
scales, if inflation had a limited duration. Inflation produced the
cosmological perturbations which are imprinted in the Cosmic Microwave
Background (CMB) radiation, and which are the ``seeds'' of the present
galaxies. The recent CMB data measured by WMAP are overall in excellent
agreement with the simplest inflationary prediction. However, they also
present a few unclear features, as for instance a hint for broken
isotropy at the largest scales. In the first part of the talk I will
present an attempt to explain this feature in terms of a primordial
anisotropy which survived a limited amount of inflation. In the second
part, I will instead discuss the reheating stage after inflation,
focusing on the role that nonperturbative effects may have played in
this period.