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. © 2011 IOP Publishing Ltd.
Faithful nonclassicality indicators and extremal quantum correlations in two-qubit states / Girolami, D.; Paternostro, M.; Adesso, G.. - In: JOURNAL OF PHYSICS. A, MATHEMATICAL AND THEORETICAL. - ISSN 1751-8113. - 44:35(2011), p. 352002.
|Titolo:||Faithful nonclassicality indicators and extremal quantum correlations in two-qubit states|
|Data di pubblicazione:||2011|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1088/1751-8113/44/35/352002|
|Appare nelle tipologie:||1.1 Articolo in rivista|
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