Reveal quantum correlation in complementary bases

TL;DR

This paper introduces a new information-theoretic approach to quantify quantum correlations by examining their invariance under basis changes, highlighting correlations in mutually unbiased bases.

Contribution

It defines measures based on basis invariance to reveal quantum correlations in complementary bases, providing a novel perspective compared to existing methods.

Findings

Quantum correlation characterized by residual correlations in mutually unbiased bases

Classical correlation as maximum correlation in an optimal basis

Measures directly reflect the essential feature of quantum correlation

Abstract

An essential feature of genuine quantum correlation is the simultaneous existence of correlation in complementary bases. We reveal this feature of quantum correlation by defining measures based on invariance under a basis change. For a bipartite quantum state, the classical correlation is the maximal correlation present in a certain optimum basis, while the quantum correlation is characterized as a series of residual correlations in the mutually unbiased bases. Compared with other approaches to quantify quantum correlation, our approach gives information-theoretical measures that directly reflect the essential feature of quantum correlation.