Aspects of inflationary cosmology

We discuss aspects of excited initial states in inflationary cosmology. We review the basic framework of inflationary cosmology and how to compute observable correlation functions. The framework of excited initial states is introduced and the corrections to the cosmological parameters are computed. We show that if the observable modes in the cosmic microwave background are excited, the amplitude of excitation is strongly bounded. We discuss equation of state parameter transitions as a physical mechanism for generating excited initial states. We describe how to interpret the bounds on excitation amplitude as bounds on the parameters of the transition.