Conceptually new mechanism for trapping neutral, polar particles

It is shown that a superposition of static and rapidly oscillating electric {\it monopole} (source) fields is capable of trapping particles with a permanent electric dipole moment. Thus, the new trapping mechanism differs fundamentally from saddle-point traps that use static and oscillating higher-multipole fields. An analytical stability analysis together with detailed molecular dynamics trajectory calculations prove that the trap is stable. Thin rods of barium titanate (BaTiO$_3$) provide an illustrative example for the working principle of the new trap. The effects of gravity are considered. The existence of a bifurcation regime is predicted. A particular strength of the new trap is that it also works for zero orbital angular momentum with respect to the field-generating electrodes.