Paul trap

Atoms and ions jiggle about randomly. To use an ion—whether in quantum information processing or in a quantum engine—one must confine it. A Paul trap offers a common solution. The trap exerts a force on the electrically charged ion, using an electric field. In the sculpture, the central gray component represents a Paul trap.

No static (constant-in-time) electric field can trap a charge in three-dimensional space, one can proving using calculus. But an electric field that changes in time can. A Paul trap’s electric field changes so quickly, the ion never has time to roll away in any one direction. The Paul trap owes its name to the German physicist Wolfgang Paul, whose trapping research earned him a Nobel Prize in 1989.