A coherent superposition principle and the Hilbertian quantum theory (Q1821323)

Our aim is to study the principle of superposition of states in an operational scheme. We suggest a formulation of this principle in the chosen scheme, and give an operational interpretation of the notion of superposition of states. The given interpretation guarantees the necessary coherence of the superposed states and it follows from the weak projection postulate, which is argued to be a presupposition of an operational description satisfying the coherent superposition principle. Such a description is shown to be equivalent with an operational hilbertian description.