Watching it Boil: Continuous Observation for the Quantum Zeno Effect

The quantum Zeno effect ( Q Z E ) is often associated with the ironic maxim. "'a watched pot never boils,'" although the notion of "watching" suggests a continuous aetieity at o(kls with the usual (pulsed measurement) presentation o f tile QZE. We show how continuous watching can provide the same halting o f decay as the usual QZE, and. for incomplete hindrance, we provide a precise connection between the interval between projections and the response time o f the continuous observer. Thus, watching closely, but not so closely as to halt the "boiling," is equivalent to--gives the same degree of partial hindrance as--pulsed measurements with a particular pulsing rate. Our demonstration is accooq~lished by treating the apparatus .~or the continuous watching as a fully quantum object. 77zis m turn allows us a secomt perspective on the QZE, in which it is the modilTed lecel structure (~f the combined system/apparatus Hamiltonian that slows the decay. This and other considerations fat:or the characterization "dominated tittle evolution"for the QZE.