2 CFU - Sandro Wimbergerkeywords: open systems, master equation, decoherence, system-bath dynamics, entanglement, density matrixThe course introduces the concept of an open quantum system and the definition of system and environment. A simple approach for the description of the reduced system's dynamics will be presented in form of the Markovian master equation for the quantum density operator. We will introduce the notions of entanglement and decoherence and study model systems such as the evolution of an atom in an external field and the collapse of wave packets.