Topological defects in conformal field theory

This thesis objective is to characterize the topological defects of a particular two dimensional conformal quantum field theory. Topological defects can be interpreted as generalizations of global symmetries and, between other things, give rise to selection rules in amplitudes. In this thesis, starting with an in-depth introduction to two dimensional conformal field theories, we will discuss the general properties of topological defects in such theories. Finally, we will explicitly describe the topological defects in a particular conformal field theory that is relevant for applications to string theory, as it describes a string moving in a space with a non-trivial topology and geometry, namely a K3 surface.