A conceptual analysis of quantum zeno; Paradox, measurement, and experiment

Arguments on controversial points concerning quantum measurement theory and the quantum Zeno effect are presented. In particular it is argued that (1)the quantum Zeno effect is a genuine result of quantum theory and current quantum measurement theory, independent of the projection postulate; (2) the effect is of very general nature and rests on analogous arguments to those involved in Bell's theories (3) the term ''quantum Zeno effect'' may usefully be restricted to experiments where a measuring device exerts a nonlocal negative-result effect on a microscopic system, mere inhibition of a transition by a directly interacting device not qualifying; (4) since no decay is truly exponential, theoretically all decay phenomena should exhibit the quantum Zeno effect under observation, continuous or discrete. A detailed study is made of the experiments claiming to demonstrate the effect; it is found that they do not meet our criterion above. (C) 1991 Academic Press.