Single ion thermal wave packet analyzed via time-of-flight detection

A single $^{40}$Ca ion is confine in the harmonic potential of a Paul trap and cooled to temperature few mK, with wave packet sub-m spatial sub-m/s velocity uncertainty. Deterministically extracted from trap, propagating over distance 0.27 m detected. By engineering extraction process on initial packet, theoretically modeling trajectories, studying experimentally time-of-flight distribution, we directly infer state previously trapped ion. This analysis allows for accurate remote sensing previous motional excitation potential, both coherently or incoherently. Our method paves way extract, manipulate design quantum packets also outside trap.