On a realistic interpretation of spontaneous decay processes

The seemingly genuine spontaneous character of radioactive decay of an individual nucleus has played a central role in the early debate concerning the interpretation of quantum mechanics. Especially Schrödinger in his famous cat-paradox used the decay of a single nucleus to demonstrate the inconsistency of the Copenhagen interpretation. That he did so is by no means a coincidence because the so-called spontaneous processes of decay seem to defy a realistic interpretation to an even greater extent than the atomic theories. Nevertheless, an attempt at such a realistic explanation will be made here on the basis of the term ‘lifetime invariance’ (for particles of the same kind), which is a result of purely theoretical considerations as well as of a, in a certain sense, new view of a sufficiently well-known fact: the dependence of lifetime on velocity during the decay of short-lived elementary particles. This seems to point directly towards a causal and realistic Bohm-type interpretation, but if the relativistic correspondence principle deduced here is taken into account, which leads to a discretization of the path as well as of space and time, one has to give up causality while realism is still rescued. Eventually we arrive at an even intuitive reconciliation of probabilism with realism, which can be designated as probabilistic realism.