Study on the high-efficiency sympathetic cooling of mixed ion system with a large mass-to-charge ratio difference in a dual radio-frequency field by numerical simulations

This study proposes a method to achieve stable confinement and efficient sympathetic cooling of a mixed ion system in dual radiofrequency (RF) traps by numerical simulations. The dynamic coupling behavior, sympathetic cooling mechanism, and efficiency-affecting factors of the dual RF ion trap system were quantitatively analyzed by molecular dynamics simulations, yielding the stable confinement conditions of three-dimensional (3D) cold ion system in dual RF confinement fields and the characteristics of 3D correlation coupling between intrinsic micromotion and secular motion. The transient processes of ion intrinsic micromotion were also investigated. Herein, a reasonable second trapping potential contributed to the efficient cooling of the ion system and suppression of its micromotion. The effects of the dual RF trapping field strength on the spatial configuration and the dynamic coupling process of sympathetic cooling were investigated in mixed 3D ion crystals with a large mass-to-charge ratio (M/Q) difference, which reveals that simultaneous stable trapping and matching dynamic modes are the key to achieving efficient sympathetic cooling in the two-component ion system. These results are applicable to studies such as quantum logic manipulation, antimatter synthesis, dark ion detection, regulation of ultracold chemical reaction processes, and precision spectral measurements based on sympathetic cooling.