Evaluating the geometric measure of quantum discord

Lei Li, Qing‐Wen Wang, Shu‐Qian Shen +1 more

Jianwei Xu

崔海涛, 田俊龙, 杨癸

Gina Passante, Osama Moussa, Raymond Laflamme

Shunlong Luo, Shuangshuang Fu

Dakic, Vedral, and Brukner [arXiv:1004.0190 (2010)] introduced a geometric measure of quantum discord and derived an explicit formula for any two-qubit state. This measure is significant in capturing quantum correlations from a geometric perspective. In this brief report, we evaluate the geometric measure of quantum discord for an arbitrary state and obtain an explicit and tight lower bound. Furthermore, we reveal an intrinsic feature of geometric measure of quantum discord by showing that it actually coincides with a simpler quantity based on von Neumann measurements.

Mingjun Shi, Fengjian Jiang, Jiangfeng Du

We present a dynamic approach to study the quantum discord and classical correlation. By local filtering operation, the evaluation of quantum discord is closely related to quantum channel and channel capacity. As a consequence, the traditional optimization over horizontal-or-vertical von Neumann measurements is replaced by that over horizontal-and-vertical three-element POVM measurement, from which more rigorous results of quantum discord are obtained.