Statistical complexity and classical-quantum frontier

The classical limit of quantum mechanics (CLQM) is a fascinating subject of perennial interest. Here we deal with it in a novel way for two of the simplest conceivable systems: the classical ideal gas (IG) and the Einstein crystal (EC). Even if at first sight one may not believe that something new could be said about them, it will be seen that some statistical quantifiers do. In particular, the statistical complexity  C, seems to signal the CLQM's zone. The associated two C−maxima (versus temperature), for, respectively, the IG and the CG, almost coincide.