Unifying approach to the quantification of bipartite correlations by Bures distance
- Autori: Bromley, T.; Cianciaruso, M.; Lo Franco, R.; Adesso, G.
- Anno di pubblicazione: 2014
- Tipologia: Articolo in rivista (Articolo in rivista)
- Parole Chiave: Bures distance; classical correlations; decoherence; quantum correlations; Mathematical Physics; Physics and Astronomy (all); Statistical and Nonlinear Physics; Modeling and Simulation; Statistics and Probability
- OA Link: http://hdl.handle.net/10447/130500
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.