Experimentally efficient methods for estimating the performance of quantum measurements

TL;DR

This paper introduces practical, scalable methods for estimating how well quantum measurements perform, using new distinguishability measures and protocols suitable for large quantum systems.

Contribution

It proposes the average measurement fidelity and error as new measures and provides experimentally accessible protocols to bound these quantities in scalable quantum systems.

Findings

Protocols for estimating measurement fidelity bounds are scalable and experimentally accessible.

Numerical examples demonstrate the effectiveness of the proposed methods.

The bounds are valid in general large quantum systems.

Abstract

Efficient methods for characterizing the performance of quantum measurements are important in the experimental quantum sciences. Ideally, one requires both a physically relevant distinguishability measure between measurement operations and a well-defined experimental procedure for estimating the distinguishability measure. Here, we propose the average measurement fidelity and error between quantum measurements as distinguishability measures. We present protocols for obtaining bounds on these quantities that are both estimable using experimentally accessible quantities and scalable in the size of the quantum system. We explain why the bounds should be valid in large generality and illustrate the method via numerical examples.