I'm trying to wrap my head around negative-result, or "interaction-free" measurements that seem to provide very real, actionable information about a system.
Such measurements are described in the Wiki article on the Elitzur-Vaidman setup https://en.wikipedia.org/wiki/Elitzur%E2%80%93Vaidman_bomb_tester and similar experiments that have followed, however to my read of it there doesn't really seem to be anything new conceptually here that wasn't covered by Renninger in 1953 with his "Negative Result" thought experiment.
Renninger, and now more recently Vaidman and co have pretty effectively shown that a "negative" or "interaction-free" measurement of a quantum system is just as effective as a traditional measurement in collapsing the system (if one wants to speak of wavefunction collapse).
So my question is really in 2 parts:
1. What, if anything, do interaction-free measurements imply about the nature of the wavefunction? It's easy to conceptualize direct measurement/interaction affecting a system, but it seems incredibly strange that the absence of interaction can be equally effective at steering a quantum system.
2. If a negative result is as effective as a positive result in steering a quantum system, why are Quantum Zeno effects not induced by the mere presence of a detector?
I surround my radioactive isotope with a fully spherically symmetrical detector that provides continuous monitoring of whether a particle has released decay products. For every instant that goes by and my detector does not click, this is just a "negative" measurement on the system, and so I can update the state of the system as having not evolved beyond its prepared state. Every further instant that passes is the same, and so it seems I should expect to observe a quantum zeno effect where my sample doesn't decay in the time expected.
My issue is this:
If both positive and negative measurements are both capable of disturbing the wavefunction, it seems anything at all should qualify as a measurement. But as that doesn't seem to be the case, I'd like some clarification from the community on what the consensus interpretation is here.