The problem with the geometric discord
Quantum Physics
2014-10-16 v2
Abstract
We argue that the geometric discord introduced in [B. Dakic, V. Vedral, and C. Brukner, Phys. Rev. Lett. 105, 190502 (2010)] is not a good measure for the quantumness of correlations, as it can increase even under trivial local reversible operations of the party whose classicality/non-classicality is not tested. On the other hand it is known that the standard, mutual-information based discord does not suffer this problem; a simplified proof of such a fact is given.
Cite
@article{arxiv.1206.0231,
title = {The problem with the geometric discord},
author = {Marco Piani},
journal= {arXiv preprint arXiv:1206.0231},
year = {2014}
}
Comments
5 pages. Changes in ver 2: typos corrected, added short proof of monotonicity of standard quantum discord under one-side action. This note is meant to stimulate discussion in the community: comments are welcome