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Condition for zero and nonzero discord in graph Laplacian quantum states
S. Dutta, B. Adhikari,
Published in World Scientific Publishing Co. Pte Ltd
Volume: 17
Issue: 2
This work is at the interface of graph theory and quantum mechanics. Quantum correlations epitomize the usefulness of quantum mechanics. Quantum discord is an interesting facet of bipartite quantum correlations. Earlier, it was shown that every combinatorial graph corresponds to quantum states whose characteristics are reflected in the structure of the underlined graph. A number of combinatorial relations between quantum discord and simple graphs were studied. To extend the scope of these studies, we need to generalize the earlier concepts applicable to simple graphs to weighted graphs, corresponding to a diverse class of quantum states. To this effect, we determine the class of quantum states whose density matrix representation can be derived from graph Laplacian matrices associated with a weighted directed graph and call them graph Laplacian quantum states. We find the graph theoretic conditions for zero and nonzero quantum discord for these states. We apply these results on some important pure two qubit states, as well as a number of mixed quantum states, such as the Werner, Isotropic, and X-states. We also consider graph Laplacian states corresponding to simple graphs as a special case. © 2019 World Scientific Publishing Company.
About the journal
JournalInternational Journal of Quantum Information
PublisherWorld Scientific Publishing Co. Pte Ltd
Open AccessNo