Thermometry of Trapped Ions Based on Bichromatic Driving

TL;DR

This paper analyzes and experimentally verifies a bichromatic driving-based thermometry method for trapped ions, demonstrating its accuracy, robustness, and efficiency across various experimental conditions and ion states.

Contribution

It provides a detailed statistical analysis and experimental validation of a novel thermometry method that remains computationally efficient with increasing ion numbers.

Findings

Method is robust to experimental imperfections.

Effective from near ground state to a few phonons.

Experimental verification on a surface-electrode trap.

Abstract

Accurate thermometry of laser-cooled ions is crucial for the performance of the trapped-ions quantum computing platform. However, most existing methods face a computational exponential bottleneck. Recently, a thermometry method based on bichromatic driving was theoretically proposed by Ivan Vybornyi et al. to overcome this obstacle, which allows the computational complexity to remain constant with the increase of ion numbers. In this paper, we provide a detailed statistical analysis of this method and prove its robustness to several imperfect experimental conditions using Floquet theory. We then experimentally verify its good performance on a linear segmented surface-electrode ion trap platform for the first time. This method is proven to be effective from near the motional ground state to a few mean phonon numbers. Our theoretical analysis and experimental verification demonstrate that the scheme can accurately and efficiently measure the temperature in ion crystals.