Quantum mechanics is acknowledged as the fundamental theory on which the whole fabric of physics is supposed to rely. And yet, the features of quantum measurements, processes that provide information about microscopic objects, seem to contradict the principles of quantum mechanics. We make a qualitative presentation of this long standing problem and give an idea of recent progress in the elucidation of the paradox. Although governed solely by the quantum equations of motion, the dynamical process involving the tested system and the measuring apparatus veils the quantum oddities that oppose our standard logic and gives rise to the expected properties of measurements. In spite of the irreducibly probabilistic nature of the underlying quantum physics, classical concepts emerge, such as standard probabilities, ordinary correlations, disappearance of quantum fluctuations, and the possibility of making statements about individual systems.
AllahverdyanA. E.BalianR.NieuwenhuizenTh. M.“Understanding quantum measurement from the solution of dynamical models”Physics Reports2013doi: 10.1016/j.physrep.2012.11.001in press arXiv:quant-ph/1107.2138. [This extensive review article (166 pages 377 references) covers the literature about models of ideal quantum measurements.]