Faithful nonclassicality indicators and extremal quantum correlations in two-qubit states

D. Girolami, Mauro Paternostro, G. Adesso

Research output: Contribution to journalArticle

63 Citations (Scopus)


The state disturbance induced by locally measuring a quantum system yields a signature of nonclassical correlations beyond entanglement. Here, we present a detailed study of such correlations for two-qubit mixed states. To overcome the asymmetry of quantum discord and the unfaithfulness of measurement-induced disturbance (severely overestimating quantum correlations), we propose an ameliorated measurement-induced disturbance as nonclassicality indicator, optimized over joint local measurements, and we derive its closed expression for relevant two-qubit states. We study its analytical relation with discord, and characterize the maximally quantum-correlated mixed states, that simultaneously extremize both quantifiers at given von Neumann entropy: among all two-qubit states, these states possess the most robust quantum correlations against noise.
Original languageEnglish
Article number352002
Pages (from-to)352002
Number of pages1
Issue number35
Publication statusPublished - 02 Sep 2011

ASJC Scopus subject areas

  • Mathematical Physics
  • Modelling and Simulation
  • Statistics and Probability
  • Physics and Astronomy(all)
  • Statistical and Nonlinear Physics

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