Primordial Fluctuations in String Cosmology
  This thesis is dedicated to the study of inflationary scenarios based on
string theory. Inflation is a brief period of accelerated expansion in the very
early Universe which gives natural explanations for problems of the Standard
Big Bang Model (SBBM) of cosmology. The phenomenological success of inflation
provides the motivation for numerous efforts to establish its connection with
particle physics. As a promising contender for a unified theory at very high
energy scales, string theory is an obvious framework to look for the
theoretical foundations of inflation; we therefore try to determine the
characteristic features of string-inspired inflationary scenarios, along with
their observational consequences. In particular, we shall be interested in
models of brane inflation, in which the inflaton field has non-canonical
dymanics and where the era of reheating is interpreted as the mutual
annihilation of (anti-)branes.
  This document contains an introduction to cosmology and string theory as well
as the model building efforts untertaken at their intersection in recent years.
The scientific articles published during the thesis are represented by a short
summary each and are available separately on the arXiv.
