Observing a Quantum Measurement

With the example of a Stern-Gerlach measurement on spin-1/2 atom, we show that superposition both paths may be observed compatibly with properties attributed to state collapse - for example, singleness (or mutual exclusivity) outcomes. This is done by inserting quantum two-state system (an ancilla) in each path, capable responding passage and thus acting as virtual detector. We then consider real measurements compound atomic spin two ancillae. Nondestructive set compatible joint observables can performed, one others properties. A novel perspective given why, within unitary theory, ordinary are blind such superpositions. Implications theory discussed.