The witness of sudden change of geometric quantum correlation

TL;DR

This paper introduces a necessary and sufficient condition to identify sudden changes in geometric quantum discord, enabling precise detection of critical points and revealing dependence on the quantum correlation measure used.

Contribution

It provides a mathematical witness for sudden changes in geometric quantum discord, applicable to both Markovian and non-Markovian cases, improving detection accuracy.

Findings

Identifies critical points of sudden quantum correlation changes.

Shows dependence of sudden change phenomena on the choice of quantum correlation measure.

Provides a method to detect sudden changes even when they are not visually obvious.

Abstract

In this paper, we give a sufficient and necessary condition (witness) for the sudden change of geometric quantum discord by considering mathematical definition of the discontinuity of a function. Based on the witness, we can find out various sudden changes of quan- tum correlation by considering both the Markovian and the non-Markovian cases. In particular, we can accurately find out critical points of the sudden changes even though they are not quite obvious in the graphical representation. In addition, one can also find that sudden change of quantum correlation, like the frozen quantum correlation, strongly depends on the choice of the quantum correlation measure.