  Recently a study of the first superposed mechanical quantum object
("machine") visible to the naked eye was published. However, as we show, it
turns out that if the object would actually be observed, i.e. would interact
with an optical photon, the quantum behavior should vanish. This, the actual
observation, has long been suspected in many interpretations of quantum
mechanics to be what makes the transition quantum $\rightarrow$ classical, but
so far it has not been available for direct experimental study in a mechanical
system. We show how any interaction, even a purely quantum one, of sufficient
strength can constitute a physical "measurement" - essentially the emergence of
an effectively classical object - active observation thus being a sufficient
but not necessary criterion. So it seems we have in this case of the "quantum
machine" a unique possibility to study, and possibly solve, the long-standing
"measurement problem" of quantum mechanics.

General Physics;Quantum Physics