Relation between conventional and dynamical formalisms in the quantum Zeno effect

The measurement-modified decay rate is calculated in two distinct formalisms, i.e., the conventional formalism and the dynamical formalism. The relation between the two formalisms is clarified, by recasting the decay rates obtained by the two formalisms into a unified form. It is shown that the dynamical formalism reproduces the conventional results only under the condition that the apparatus detects the decayed states with an identical response time.