On the Operational Theory of General (Quantum) Stochastic Processes

This thesis is concerned with the description, characterization, and structural analysis of general physical processes. While all of these questions are well understood in classical physics, the situation presents itself much murkier in the realm of quantum mechanics, where fundamental classical properties fail to hold. Here, we close this conceptual gap and provide the theoretical foundation for the description of processes in classical physics, quantum mechanics, and beyond. These findings, in turn, enable the experimental investigation of key properties of dynamical processes, like, for example, the existence of memory effects and their respective temporal structure.