Tight lower bound to the geometric measure of quantum discord
Abstract
Dakic, Vedral and Brukner [Physical Review Letters \tf{105},190502 (2010)] gave a geometric measure of quantum discord in a bipartite quantum state as the distance of the state from the closest classical quantum (or zero discord) state and derived an explicit formula for a two qubit state. Further, S.Luo and S.Fu [Physical Review A \tf{82}, 034302 (2010)] obtained a generic form of this geometric measure for a general bipartite state and established a lower bound. In this brief report we obtain a rigorous lower bound to the geometric measure of quantum discord in a general bipartite state which dominates that obtained by S.Luo and S.Fu.
Keywords
Cite
@article{arxiv.1010.1920,
title = {Tight lower bound to the geometric measure of quantum discord},
author = {Ali Saif M. Hassan and Behzad Lari and Pramod S. Joag},
journal= {arXiv preprint arXiv:1010.1920},
year = {2015}
}
Comments
10 pages,2 figures. In the previous versions, a constraint was ignored while optimizing the second term in Eq.(5), in which case, only a lower bound on the geometric discord can be obtained. The title is also consequently changed. Accepted in Phys.Rev.A