Microfabricated Penning trap for quantum computation and simulation

Trapped ion quantum information processors as well as all competing platforms are facing a challenging task to scale up their qubit registers. Trapped ion systems typically use strong radio-frequency (r.f.) fields for confinement, which present a technological challenge in delivering the required power to miniaturized surface traps with a two-dimensional geometry. Such a geometry is desired for scaling in a large information process but is fundamentally at odds with the fact that any ions straying away from one-dimensional r.f. nulls suffer excess micromotion. We instead envision a two-dimensional array of Penning traps that will operate free from the detrimental strong r.f. fields: a repeating pattern of dc electrodes on a microfabricated trap chip with static quadrupole potentials will create an axial confinement at each trap site and in combination with a strong and homogenous magnetic field generate radial confinement. Each individual trap site would then host a single ion and would be easily reconfigurable to adjust the distance to a neighboring site to allow for tunable coupling strengths. To demonstrate the feasibility of this approach, we built an experimental apparatus that houses a micro-fabricated trap capable of creating two radially separated trapping wells inside a cryogenic vacuum chamber inserted into the bore of a 3 T superconducting magnet. We report on the first successful loading of (9)Be(+ )ions into the trap. The results highlight our ability to successfully cool the radial motion using the radial motional mode coupling technique known as axialization.

Automated summary

Trapped ion quantum information processors face a challenge in scaling up their qubit registers, but a two-dimensional array of Penning traps may provide a solution.