Suppose we want to observe the wave function collapse. In that case, we should guarantee 1) that it occurs within reasonable times (neither too long nor too short from the experimental perspective) and 2) that decoherence does not suppress the quantum interference before collapse takes place. We can control the first condition via the number of atoms, tuning the collapse time as we wish. The second condition, however, requires much more strict control of the environmental parameters. First, the entire system (as opposed to a subsystem) should be in the quantum superposition to avoid coherence delocalization over the environment. Second, for the same reason, the experiment should be in an extreme vacuum, possibly