Abstract

Since the advent of quantum theory founded nearly a century ago, non-commutativity of quantum observables has undoubtedly been one of the major sources of troubles we face when we try to interpret their measurement outcomes in a sensible manner. This has naturally led to various attempts of "quantisation" of classical systems in terms of non-commuting Hilbert space operators, or conversely of "quasi-classical" interpretation of quantum systems in terms of commuting quantities familiar to us in classical theory.