Figure 3

Grounding the RF ring and applying 1 V to the top electrodes, we plot the numerical electric potential. The oblate Paul trap’s electrodes are shown as the solid magenta lines. (a) In the plane the electrostatic potential due to the top electrodes has a gradient along the direction. This gradient produces an electrostatic force that confines the ions in the center of the trap. (The dashed magenta line shows the plane of panel (b).) (b) The electrostatic potential is shown in the plane, where the dashed magenta line shows the plane of panel (a). For the actual DC voltage applied to the trap, we multiply the potential by actual voltage difference.