Last year, I presented a talk in which I exploited Wigner transforms and measures (and some other powerful tools) in order to get a precise quantum-classical correspondence in Physics. In the present talk, I will shortly remind the key concepts of both quantum and classical theories and show how the latter can be re-obtained from the former using only wave-packet approximations and evaluating the error they introduce in the Schrödinger equation. I will finish by analysing an interesting example where the wave-packets allow us to obtain the classical motion of a particle even through ill-defined classical trajectories.
