Real-time capable CCD-based individual trapped-ion qubit measurement

TL;DR

This paper demonstrates real-time capable CCD-based measurement of individual trapped-ion qubits, achieving results comparable to traditional PMT detection, and discusses error sources and crosstalk in the system.

Contribution

It introduces a real-time processing EMCCD camera system for single-ion qubit readout, enabling faster quantum measurements with comparable accuracy to existing methods.

Findings

Achieved real-time detection of $^9$Be$^+$ ion qubits.

Error rates around 0.5% due to state preparation and measurement.

Analyzed crosstalk and error sources in the detection system.

Abstract

Individual-qubit readout is a key ingredient for quantum simulation and quantum computation. Furthermore, this readout must take place in real-time to enable the application of quantum error-correction protocols. In this paper the capability of an EMCCD camera with a real-time processing capable output is demonstrated to determine the quantum state of a single $^9$Be$^+$ ion and the required timing sequences are explored. The results are comparable to a PMT based detection. Experiments on the individual detection of $^9$Be$^+$ qubit states undergoing coherent excitation are reported. Sources of error and the amount of crosstalk in the detection system are discussed. Error rates due to known problems in the state preparation and measurement processes were determined to be approximately 0.5 %.