Physical Review A
Exact classical limit of quantum mechanics: Noncentral potentials and Ermakov-type invariants
Adam J. Makowski
Abstract
Two-dimensional noncentral potentials are derived in the exact classical limit of quantum mechanics where the quantum correction to the classical Hamilton-Jacobi equation is canceled. It is then shown explicitly that there exist Ermakov-type invariants I for a large class of such potentials. Some of the invariants are found to be positive definite, $I>0,$ and for the other, we have found $I=0.$