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arXiv · 1404.1409

Unifying approach to the quantification of bipartite correlations by Bures distance

Thomas R. Bromley·Marco Cianciaruso·Rosario Lo Franco·Gerardo Adesso
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Abstract

The notion of distance defined on the set of states of a composite quantum system can be used to quantify total, quantum and classical correlations in a unifying way. We provide new closed formulae for classical and total correlations of two-qubit Bell-diagonal states by considering the Bures distance. Complementing the known corresponding expressions for entanglement and more general quantum correlations, we thus complete the quantitative hierarchy of Bures correlations for Bell-diagonal states. We then explicitly calculate Bures correlations for two relevant families of states: Werner states and rank-2 Bell-diagonal states, highlighting the subadditivity which holds for total correlations with respect to the sum of classical and quantum ones when using Bures distance. Finally, we analyse a dynamical model of two independent qubits locally exposed to non-dissipative decoherence channels, where both quantum and classical correlations measured by Bures distance exhibit freezing phenomena, in analogy with other known quantifiers of correlations.

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Thomas R. Bromley, Marco Cianciaruso, Rosario Lo Franco, Gerardo Adesso. 2014-04-04. Unifying approach to the quantification of bipartite correlations by Bures distance. https://doi.org/10.1088/1751-8113/47/40/405302

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