Quantum Information Processing with Atoms and Photons

In this thesis, we present new tools for the study of quantum systems and propose several novel schemes for practical applications in quantum information science. We explore two main topics, engineered dissipation and light-matter quantum interfaces, and investigate both with a focus on collective effects that arise if a large number of particles interact coherently with an optical quantum field. To this end, we study atomic vapor at room temperature interacting with light. We also consider ultracold atoms in optical lattices, Bose-Einstein condensates and single atoms in optical cavities for the implementation of the ideas and schemes put forward here.