Natural Models of Inflation

This project explore the possibility that the inflaton, the particle responsible for inflation, could be a composite state. The inflaton is traditionally modelled as a fundamental scalar, but only one possible fundamental scalar have yet been discovered, making an alternative attractive. Working in different particle setups I will show that inflation from a composite inflaton is a valid alternative to the fundamental scalar inflaton and that it might even be a more natural way to explain an inflationary era. I show that inflation with a composite inflaton can arise from technicolor models and from pure Yang - Mills theories. Furthermore the scale of the effective describtion of such theories are the Grand Unification scale, insuring a valid effective describtion through the inflationary era. I describe three models, at this point two of them are working theories of inflation, with one of them not yet excluded by experiments.