Quantum electrodynamics of one-photon wave packets

In this contribution we investigate quantum electrodynamical many-mode aspects by exploring the simplest possible situation in this context, namely the interaction of a single atom, modeled by a simple two-level system, with many-mode one-photon quantum states of the electromagnetic field. In particular, we concentrate on the question how the engineering of electromagnetic field modes influences the atom-field interaction. An interesting problem in this context is the engineering of ideal one-photon multi-mode quantum states which may excite a single atom perfectly [M. Stobi\'nska, G. Alber, and G. Leuchs, EPL {\bf 86}, 14007 (2009)]. For purposes of quantum information processing such one-photon multi-mode states are particularly well suited for transmitting quantum information and for storing it in a material memory again.