Role of weak measurements on states ordering and monogamy of quantum correlation

TL;DR

This paper investigates how weak measurements influence the ordering and monogamy of quantum correlations, revealing that they can both reveal more quantumness and induce counterintuitive effects, affecting quantum resource utility.

Contribution

It demonstrates that weak measurements can alter the ordering and monogamous properties of quantum correlations, highlighting their dual role in quantum information theory.

Findings

Weak measurements can change the ordering of quantum correlations.

They can modify the monogamous nature of certain quantum states.

Weak measurements can both enhance and diminish quantum resource usefulness.

Abstract

The information-theoretic definition of quantum correlation, e.g., quantum discord, is measurement dependent. By considering the more general quantum measurements, weak measurements, which include the projective measurement as a limiting case, we show that while weak measurements can enable one to capture more quantumness of correlation in a state, it can also induce other counterintuitive quantum effects. Specifically, we show that the general measurements with different strengths can impose different orderings for quantum correlations of some states. It can also modify the monogamous character for certain classes of states as well which may diminish the usefulness of quantum correlation as a resource in some protocols. In this sense, we say that the weak measurements play a dual role in defining quantum correlation.