Spontaneous emission and quantum discord: comparison of Hilbert-Schmidt and trace distance discord

TL;DR

This paper compares Hilbert-Schmidt and trace distance quantum discord during spontaneous emission in two-level atoms, finding that Hilbert-Schmidt discord exhibits nonphysical behavior and trace distance discord is more reliable.

Contribution

It demonstrates that Hilbert-Schmidt quantum discord has nonphysical properties in local evolution, advocating for trace distance discord as a better measure of quantum correlations.

Findings

Hilbert-Schmidt discord shows nonphysical behavior during spontaneous emission.

Trace distance discord remains physically consistent during local evolution.

Trace distance discord is recommended over Hilbert-Schmidt discord for measuring quantum correlations.

Abstract

Hilbert - Schmidt and trace norm geometric quantum discord are compared with regard to their behavior during local time evolution. We consider the system of independent two - level atoms with time evolution given by the dissipative process of spontaneous emission. It is explicitly shown that the Hilbert - Schmidt norm discord has nonphysical properties with respect to such local evolution and cannot serve as a reasonable measure of quantum correlations and the better choice is to use trace norm discord as such a measure.