Angular Operators Violating the Heisenberg Uncertainty Principle
Tiago Pereira, Domingos H. U. Marchetti
Abstract
The description of a quantum system in terms of angle variables may violate Heisenberg uncertainty principle. The familiar case is the azimutal angle $\phi$ and its canonical moment $L_z$. Although this problem was foreseen almost a century ago, up to the present days there are no criteria to precisely characterize the violation. In this paper, we present a theorem which provides necessary and sufficient conditions for the violation of the Heisenberg uncertainty principle. We illustrate our results with analytical examples.