Classical and Quantum Superintegrability of St\"ackel Systems

In this paper we discuss maximal superintegrability of both classical and quantum St"ackel systems. We prove a sufficient condition for a flat or constant curvature St"ackel system to be maximally superintegrable. Further, we prove a sufficient condition for a St"ackel transform to preserve maximal superintegrability and we apply this condition to our class of St"ackel systems, which yields new maximally superintegrable systems as conformal deformations of the original systems. Further, we demonstrate how to perform the procedure of minimal quantization to considered systems in order to produce quantum superintegrable and quantum separable systems.