2013/02/01 by Jacek Jurkowski, JACEK JURKOWSKI · 17 citations
Computer Science · Physics and Astronomy · #Ambiguity #Computer science #Entropy (arrow of time) #Mathematical physics #Physics #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum discord #Quantum entanglement #Quantum mechanics #Qubit #Statistical Mechanics and Entropy #Statistical physics #Tsallis entropy
paper · doi:10.1142/s0219749913500135
published in International Journal of Quantum Information 11(01), 1350013 (World Scientific)
crossref issued 2013/02/01 · crossref published 2013/02/01 · crossref published-print 2013/02/01 · openalex publication_date 2013/02/01 · crossref created 2013/04/16 · crossref published-online 2013/05/14 · crossref deposited 2019/08/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22 · crossref indexed 2026/08/03
Due to some ambiguity in the definition of mutual Tsallis entropy in classical probability theory, its generalization to quantum theory is discussed and, as a consequence, two types of generalized quantum discords, called q-discords, are defined in terms of quantum Tsallis entropy. Both q-discords for two-qubit Werner and isotropic states are determined and compared and it is shown that one of them is non-negative, at least for states under investigation, for all q > 0. Finally, an analytical expression for q-discord of certain family of two-qubit X-states is presented. Using this example, we show that both types of q-discords can take negative values for some q > 1, hence their use as correlations measures is rather limited.