Informational power of quantum measurements

TL;DR

This paper introduces the concept of informational power for quantum measurements, showing it equals the classical capacity of a quantum-classical channel, and provides a numerical method to evaluate it.

Contribution

It defines the informational power of quantum measurements, proves its additivity, and offers a numerical algorithm to compute it.

Findings

Informational power equals the classical capacity of a quantum-classical channel.

The paper proves the additivity of informational power.

Provides a numerical algorithm to evaluate the informational power.

Abstract

We introduce the informational power of a quantum measurement as the maximum amount of classical information that the measurement can extract from any ensemble of quantum states. We prove the additivity by showing that the informational power corresponds to the classical capacity of a quantum-classical channel. We restate the problem of evaluating the informational power as the maximization of the accessible information of a suitable ensemble. We provide a numerical algorithm to find an optimal ensemble, and quantify the informational power.