Characterization of Fast Ion Transport via Position-Dependent Optical Deshelving

TL;DR

This paper introduces a position-dependent optical deshelving method to analyze ion transport dynamics in quantum information processing, revealing deviations from intended trajectories during fast ion shuttling.

Contribution

The study presents a novel optical technique to sample ion positions during transport, providing detailed insights into ion dynamics in surface-electrode traps.

Findings

Measured average ion speed of 83 m/s during transport

Observed peak ion speed of 251 m/s

Identified distortions in the transport waveform due to electrode filtering

Abstract

Ion transport is an essential operation in some models of quantum information processing, where fast ion shuttling with minimal motional excitation is necessary for efficient, high-fidelity quantum logic. While fast and cold ion shuttling has been demonstrated, the dynamics and specific trajectory of an ion during diabatic transport have not been studied in detail. Here we describe a position-dependent optical deshelving technique useful for sampling an ion's position throughout its trajectory, and we demonstrate the technique on fast linear transport of a $^{40}\text{Ca}^+$ ion in a surface-electrode ion trap. At high speed, the trap's electrode filters strongly distort the transport potential waveform. With this technique, we observe deviations from the intended constant-velocity (100 m/s) transport: we measure an average speed of 83(2) m/s and a peak speed of 251(6) m/s over a distance of 120 $\mu$m