Coherence properties of highly-excited motional states of a trapped ion

TL;DR

This paper investigates the coherence times of highly-excited motional states of a trapped ion, demonstrating long coherence times and introducing a new preparation technique for incoherent superpositions.

Contribution

It presents a novel method for preparing incoherent superpositions of motional states and measures their coherence properties in a Penning trap.

Findings

Ion motional states have coherence times around one second.

The introduced preparation technique creates incoherent superpositions.

Highly-excited motional states maintain long coherence despite incoherent preparation.

Abstract

We present a study of the coherence properties of a variety of motional states of a single ion confined in a Penning ion trap. We demonstrate that the motion of the ion has a coherence time of the order of one second, using Ramsey interferometry. We introduce a technique for preparing the ion in an incoherent superposition of highly-excited motional states using a simple modification of optical sideband cooling. Coherent manipulation of these states allow measurements of optical and motional coherence to be carried out. We show that these highly-excited motional state superpositions have long coherence times despite the incoherent preparation of the states. Such states can be useful for sensitive motional dephasing measurements.