Curator's Take
This research tackles a critical engineering challenge in trapped-ion quantum computers: how to move ions vertically between different trap zones without destroying their delicate quantum states. The team demonstrates that ions can be shuttled up to 86 micrometers in just half a millisecond while keeping motional heating below eight quanta, which is remarkable precision for maintaining quantum coherence. These vertical shuttling protocols could enable more sophisticated 3D ion trap architectures that dramatically improve laser access for quantum operations and allow for better on-chip detection systems. The work represents important progress toward scalable trapped-ion quantum computers that can move qubits around complex chip architectures without losing the quantum information stored within them.
— Mark Eatherly
Summary
We investigate optimized vertical ion-shuttling protocols for trapped-ion applications across a range of ion-trap experiments, including three-dimensional gradient-measurement sensors, on-chip ion fluorescence collection and imaging, improved laser accessibility, and quantum information processing. In this work, we focus on minimizing motional energy gain during ion transport. Our findings indicate that anomalous heating becomes the dominant limiting factor only for shuttling durations exceeding $500~μ\mathrm{s}$, whereas the final motional excitation is strongly dependent on the selected transport protocol. Using a recently measured heating rate of $(3.1 \pm 0.35)$ quanta/ms at an ion--surface separation of $134 \pm 1.5~μ\mathrm{m}$, we demonstrate that the motional excitation can be restricted to fewer than eight quanta when the ion is vertically displaced by $86~μ\mathrm{m}$ from its initial position. These results enable adiabatic shuttling within $0.5~\mathrm{ms}$, thereby meeting the operational requirements for high-fidelity quantum sensing and coherent control.