Observable nonclassical correlation effects in the dynamics of a bidimensionally confined ion

The occurrence of a peculiar correlation effect in the quantum dynamics of an ion confined in a 2D Paul microtrap is reported. We analytically find th at when the ion, prepared in a SU(2) vibrational coherent state, is irradia ted by two orthogonal laser beams, the time evolution of the quantum covari ance between two clearly interpretable bosonic observables displays an high sensitivity to the initial state parameters. Both the nonclassical nature of this effect and a simple proposal for its detection is briefly discussed .