Correlations in quantum states and the local creation of quantum discord
Abstract
Quantum discord is usually referred to as a measure for quantum correlations. In the search of the fundamental resource to gain a quantum advantage in quantum information applications, quantum discord is considered a promising candidate. In this paper we present an alternative view on quantum correlations in terms of the rank of the correlation matrix as introduced by Dakic, Vedral, and Brukner [Phys. Rev. Lett. 105, 190502 (2010)]. According to our analysis, information about the quantum discord does not necessarily determine the amount of quantum correlations but rather the quantumness of the state. Nonzero quantum discord is only a necessary but not a sufficient condition for correlations above the classically achievable limit. This becomes clear when we consider states of nonzero discord, which can be created from zero discord states only by a single local operation. We further show that the set of these states has measure zero.
Keywords
Cite
@article{arxiv.1202.1959,
title = {Correlations in quantum states and the local creation of quantum discord},
author = {Manuel Gessner and Elsi-Mari Laine and Heinz-Peter Breuer and Jyrki Piilo},
journal= {arXiv preprint arXiv:1202.1959},
year = {2012}
}