Quantum reference systems: A new framework for quantum mechanics

The new concept of quantum reference systems is introduced, and a corresponding new foundation of nonrelativistic quantum mechanics is given in terms of a set of postulates. The resulting theory gives an explanation for the measurement without assuming an a priori classical background. Schrödingerʹs cat paradox and the Einstein-Podolsky-Rosen paradox gain resolution, too. It is also shown that, despite the violation of Bellʹs inequality, quantum mechanics is a local theory