Control Method of Cooling a Charged Particle Pair in a Paul Trap

We propose a simple feedback cooling method, including both the component feedback and the velocity feedback, for cooling a charged particle pair in a Paul trap. It is found that the system can be cooled to periodic orbits; and if control intensity is strong, the system can be cooled to a one-periodic orbit, which is only in a horizontal plane. The result shows that the cooled system is also robust for noise.