Precision measurements in ion traps using slowly moving standing waves

TL;DR

This paper introduces a high-precision, simplified method using a slowly moving standing wave to measure key parameters in ion traps, aiding quantum computing applications.

Contribution

It presents a novel experimental technique employing a slowly moving optical standing wave for precise measurements in ion traps, simplifying setup requirements.

Findings

Accurate measurement of ion-ion distance in standing wave units.

Determination of Lamb-Dicke parameter with high precision.

Assessment of ion crystal temperature and interferometric stability.

Abstract

The present paper describes the experimental implementation of a measuring technique employing a slowly moving, near resonant, optical standing wave in the context of trapped ions. It is used to measure several figures of merit that are important for quantum computation in ion traps and which are otherwise not easily obtainable. Our technique is shown to offer high precision, and also in many cases using a much simpler setup than what is normally used. We demonstrate here measurements of i) the distance between two crystalline ions, ii) the Lamb-Dicke parameter, iii) temperature of the ion crystal, and iv) the interferometric stability of a Raman setup. The exact distance between two ions, in units of standing wave periods, is very important for motional entangling gates, and our method offers a practical way of calibrating this distance in the typical lab situation.