Tsallis’ deformation parameter q quantifies the classical–quantum transition

We investigate the classical limit of a type of semiclassical evolution, the pertinent system representing the interaction between matter and a given field. On using Tsallis q-entropy as a quantifier of the ensuing dynamics, we find that it not only appropriately describes the quantum–classical transition, but that the associated deformation-parameter q itself characterizes the different regimes involved in the process, detecting the most salient fine details of the changeover.