I don't know Quantum Decoherence in detail, but I know its trying to say that wave function collapse is a result of the interaction of the system with its environment and the fact that it seems wave function collapse is incompatible with Schrodinger evolution, is only because the system alone doesn't evolve Schrodingerically but the evolution of system+environment is of course based on Schrodinger equation. It seems so nice of a theory and so compatible with observations that I thought its a very good candidate for a solution to the measurment problem. But now comes the Renninger negative-result experiment(I assume you either read the article I gave the link to or already know about it.) My point is, this experiment illustrates that at least a partial wave function collapse can occur without an interaction between system and environment because the space between the detectors can be a vacuum. Otherwise we are forced to include non-local interactions(or maybe interaction with a non-trivial vacuum?) Anyway, to me, this experiment seems to be at odds with Quantum Decoherence. At least its not obvious that they're compatible! Any ideas?