Classical and quantum correlations under decoherence

TL;DR

This paper investigates how classical and quantum correlations evolve under decoherence, revealing sudden changes in decay rates and conditions where classical correlations remain unaffected, leading to an operational measure of correlations.

Contribution

It identifies three types of correlation dynamics under decoherence and proposes a measure of correlations that avoids extremization procedures.

Findings

Classical correlations can be unaffected by decoherence under certain conditions.

Correlations exhibit a sudden change in decay rates during decoherence.

An operational measure of correlations is proposed that does not require extremization.

Abstract

Recently some authors have pointed out that there exist nonclassical correlations which are more general, and possibly more fundamental, than entanglement. For these general quantum correlations and their classical counterparts, under the action of decoherence, we identify three general types of dynamics that include a peculiar sudden change in their decay rates. We show that, under suitable conditions, the classical correlation is unaffected by decoherence. Such dynamic behavior suggests an operational measure of both classical and quantum correlations that can be computed without any extremization procedure.