Quantum Steering and state engineering: A stupid passive approach vs. a clever active decision making

Weak measurement  is an alternative to von Neumann’s dogma of the “collapse” of a wave function: it avoids the necessity of the latter’s complete destruction, while capable of extracting partial information from the system measured. Concomitantly, measurement is associated with a back-action of the detector on the system’s state. This back-action can be harnessed for the purpose of steering a quantum state into a pre-designated target state, and for quantum engineering of non-trivial states of matter. I will try to package this all together, elucidating the difference between a stupid passive protocol, and an active one, where decisions made by a smart observer may improve the performance of quantum steering.