Angular momenta of neutral particles interacting with electromagnetic fields

We study rotational properties of neutral particles interacting with electromagnetic fields in some specific configurations. We show that although the configurations possess rotational symmetry, the kinetic angular momenta of particles are not always conserved. However, the canonical angular momenta of particles are conserved and always equal to the total angular momenta, i.e. sum of kinetic angular momenta of the particle and electromagnetic fields, regardless of whether the kinetic angular momenta are conserved or not. The differences between our studies and the case of a charged particle in the background of a uniform magnetic field are analyzed.