REPEATABLE MEASUREMENTS IN QUANTUM-THEORY - THEIR ROLE AND FEASIBILITY

Recent advantages in experimental quantum physics call for a careful reconsideration of the measurement process ill quantum mechanics. III this paper we describe the structure of the ideal measurements and their status among the repeatable measurements. Then we provide an exhaustive account of the interrelations between repeatability and the apparently weaker notions of value reproducible oi first-kind measurements. We demonstrate the close link between repeatable measurements and discrete observables and show how the ensuing measurement limitations for continuous observables can be lifted in a way that is ill full accordance with actual experimental practice. We present examples of almost repeatable measurements of continuous observables and some realistic models of weakly disturbing measurements.