Transition to the classical regime in quantum mechanics on a lattice and implications of discontinuous space

Abstract

It is well known that, due to the uncertainty principle, the Planck constant sets a resolution boundary in phase space and the resulting trade-off in resolution between incompatible measurements has been thoroughly investigated. It is also known that, in the classical regime, sufficiently coarse measurements of position and momentum can simultaneously be determined. However, the picture of how the uncertainty principle gradually disappears as we transition from the quantum to the classical regime is not so vivid. In the present work we clarify this picture by studying the associated probabilities that quantify the effects of the uncertainty principle in the framework of finite-dimensional quantum mechanics on a lattice. We also study how these probabilities are perturbed by the granularity of the lattice and show that they can signal the discontinuity of the underlying space.