Description
Although radio-frequency (r.f.) traps have been widely used in trapped-ion quantum information and simulation, they face some inherent challenges in scaling up the number of qubits. Precise alignment of static and r.f. field nulls is necessary to achieve confinement of the ions without r.f. driven motion. As the r.f. null is inherently 1-dimensional, attempts at scaling into 2-d are beset by micromotion.
Instead we propose to use a two-dimensional array of Penning traps, implemented by micro-fabricated electrodes. Applying suitable electrical potentials to the surface electrodes generates an array of quadrupole fields above the chip, with a single ion trapped at each. This allows for individual control of secular frequencies and trapping heights with coupling provided by the Coulomb interaction. Micromotion and bulk crystal rotation are absent in this approach.
We have constructed an experimental apparatus containing the first micro-fabricated planar Penning trap in a 3 T field. The trap can produce a potential with two trap sites separated radially. To achieve ultra-high vacuum and low ion heating rates, the trap is held at cryogenic temperatures of around 6 K, with optics to allow for imaging and laser manipulation of ions as part of the cryogenic structure as well.
We report on our current efforts to initially trap ${^{9}{\rm Be}^{+}}$ ions in this setup. Potential challenges that may prevent successful trapping are identified. We attempt cooling of the radial motion by the axialisation technique, coupling the cyclotron and magnetron motions. The required strength of the weak coupling r.f. field is predicted as well as the precision of positioning of the r.f. null. Stray electric potentials may lead to unstable trapping conditions as well as perturb the axialisation frequency, requiring appropriate compensation. Neutral ${{\rm Be}}$ atoms are produced by pulsed-laser ablation, a process we have studied in depth.
| Presenter name | Tobias Sägesser |
|---|---|
| How will you attend ICAP-27? | I am planning on in-person attendance |
