Show simple item record 2016-09-09T13:50:16Z 2016-09-09T13:50:16Z 2013 es
dc.title Generalized conditional entropy in bipartite quantum systems en
dc.type Artículo es
dcterms.abstract We analyze, for a general concave entropic form, the associated conditional entropy of a quantum system A+B, obtained as a result of a local measurement on one of the systems (B). This quantity is a measure of the average mixedness of A after such measurement, and its minimum over all local measurements is shown to be the associated entanglement of formation between A and a purifying third system C. In the case of the von Neumann entropy, this minimum determines also the quantum discord. For classically correlated states and mixtures of a pure state with the maximally mixed state, we show that the minimizing measurement can be determined analytically and is universal, i.e., the same for all concave forms. While these properties no longer hold for general states, we also show that in the special case of the linear entropy, an explicit expression for the associated conditional entropy can be obtained, whose minimum among projective measurements in a general qudit-qubit state can be determined analytically, in terms of the largest eigenvalue of a simple 3 × 3 correlation matrix. Such minimum determines the maximum conditional purity of A, and the associated minimizing measurement is shown to be also universal in the vicinity of maximal mixedness. Results for X states, including typical reduced states of spin pairs in XY chains at weak and strong transverse fields, are also provided and indicate that the measurements minimizing the von Neumann and linear conditional entropies are typically coincident in these states, being determined essentially by the main correlation. They can differ, however, substantially from that minimizing the geometric discord. en
dcterms.extent 11 p. es
dcterms.issued 2013 es
dcterms.language Inglés es
dcterms.license Attribution 4.0 International (BY 4.0) es
dcterms.publisher IOPscience es
dcterms.subject Teoría Cuántica es
dcterms.subject Entropía es
cic.version info:eu-repo/semantics/submittedVersion es Gigena, Nicolás es Rossignoli, Raúl Dante es
cic.lugarDesarrollo Universidad Nacional de La Plata es
dcterms.subject.materia Ciencias Físicas es
dcterms.identifier.url Documento completo es
dcterms.isPartOf.issue vol. 47, nº 1 es
dcterms.isPartOf.series Journal of Physics A: Mathematical and Theoretical es
cic.isPeerReviewed true es
cic.isFulltext true es


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