Understanding quantum measurement from the solution of dynamical models

摘要: The quantum measurement problem, understanding why a unique outcome is obtained in each individual experiment, tackled by solving models. After an introduction we review the many dynamical models proposed over years. A flexible and rather realistic model introduced, describing of $z$-component spin through interaction with magnetic memory simulated Curie--Weiss magnet, including $N \gg1$ spins weakly coupled to phonon bath. Initially prepared metastable paramagnetic state, it may transit its up or down ferromagnetic triggered coupling tested spin, so that magnetization acts as pointer. A detailed solution equations worked out. Conditions are found, which ensure process satisfies features ideal measurements. Various imperfections discussed, well attempts incompatible first steps consist Hamiltonian dynamics for spin-apparatus density matrix $D(t)$. On longer time scale, trend towards equilibrium magnet produces final state $D(t_{\rm f})$ involves correlations between system indications pointer, thus ensuring registration. difficulty lies ambiguity: There exist decompositions $\scriptD(t_{\rm f})$. This overcome due suitable interactions within apparatus. Any subset runs reaches brief delay stable same hierarchic property classical probability theory. Standard statistical mechanics alone appears sufficient explain occurrence answer run. Finally, pedagogical exercises while interpretation promoted teaching. [Abridged]