Metrological measures of non-classical correlations

TL;DR

This paper reviews how metrological measures quantify non-classical correlations in quantum systems and their role in enhancing sensitivity in quantum metrology tasks like interferometry and state discrimination.

Contribution

It provides a comprehensive review of metrological measures of non-classical correlations and their connection to improved quantum sensing performance.

Findings

Metrological measures relate to increased probe sensitivity.

Non-entangled states can exhibit useful non-classical correlations.

Enhanced quantum metrology protocols leverage these correlations.

Abstract

Non-classical correlations denote the ways in which quantum systems can be correlated beyond what is possible in classical physics. They include but are not limited to entanglement: non-entangled states can also exhibit forms of non-classical correlations. We here review the literature on metrological measures of non-classical correlations and show how they relate to increased probe sensitivity in quantum metrology protocols such as interferometric parameter estimation and state discrimination.