Is the SIC Outcome There When Nobody Looks?

TL;DR

This paper explores the nature of symmetric informationally complete measurements (SICs) in quantum information, revealing their optimality and their role in understanding quantum-classical deviations.

Contribution

It uncovers a new relation between different measures of quantum deviation from classical expectations using sporadic SICs.

Findings

SICs are shown to be optimal among informationally complete measurements.

A novel relation between quantum deviations and classical expectations is identified.

Insights into the structure of quantum measurements and their classical limits are provided.

Abstract

Informationally complete measurements are a dramatic discovery of quantum information science, and the symmetric IC measurements, known as SICs, are in many ways optimal among them. Close study of three of the "sporadic SICs" reveals an illuminating relation between different ways of quantifying the extent to which quantum theory deviates from classical expectations.