Fock-state view of weak-value measurements and implementation with photons and atomic ensembles

Weak measurements in combination with post-selection can give rise to a striking amplification effect (related to a large "weak value"). We show that this effect can be understood by viewing the initial state of the pointer as the ground state of a fictional harmonic oscillator, helping us to clarify the transition from the weak-value regime to conventional dark-port interferometry. We then describe how to implement fully quantum weak-value measurements combining photons and atomic ensembles.