Super Quantum Discord and Inferior “Geometric Discord” Based on Weak Measurement in Noninertial Frames

Abstract

Instead of projective measurement, we use weak measurement to define quantum and geometric discords, and compare them with the normal quantum and geometric discords based on the projective measurement in noninertial frames. We find that using weak measurement to define quantum discord we can capture more quantum correlations compared with the projective measurement, so calling it super quantum discord. However, we note that the geometric discord based on the weak measurements becomes smaller, so we name it inferior "geometric discord". We also show that, although both the super quantum discord and the inferior "geometric discord" decrease with the increase of observer's acceleration, the super quantum discord/inferior "geometric discord" increases/decreases as the measurements become weak. These differences reveal that the definitions of the quantum and geometric discords are not too concordant with each other.

Weak quantum discord

“…This fact was corroborated by a number of works via explicit calculations involving two-qubit states [40,41,42,43]. However, as pointed out by Xiang and Jing, who also noticed the discrepancy between the super quantum discord and the weak geometrical quantum discord in contexts involving non-inertial reference frames [44], there seems to be some inconsistency in all this.…”