The goal of this book is to apply system and control theory to two system classes originating from different fields of physics: process systems and quantum mechanical systems. Using the quasi-polynomial system representation it is possible to describe the dynamic behavior of general nonlinear process systems. It is shown in the work, that global stability analysis for such systems can be performed algorithmically, moreover, a globally stabilizing state feedback design method is given. Only a few authors tried to apply control theory in quantum mechanical fields. The aimed problem of the second part of the dissertation is quantum state estimation, where the state of a quantum system is to be determined from quantum measurement. The problem is solved in two different ways.