The distance between a quantum state and its closest state not having a certain property has been used to quantify the amount of correlations corresponding to that property. This approach allows a unified view of the various kinds of correlations present in a quantum system. In particular, using relative entropy as a distance measure, total correlations can be meaningfully separated into a quantum part and a classical part thanks to an additive relation involving only the distances between states. Here we investigate a unified view of correlations using as a distance measure the square norm, which has already been used to define the so-called geometric quantum discord. We thus also consider geometric quantifiers for total and classical correlations, finding, for a quite general class of bipartite states, their explicit expressions. We analyze the relationship among geometric total, quantum, and classical correlations, and we find that they no longer satisfy a closed additivity relation.
|Numero di pagine||9|
|Rivista||PHYSICAL REVIEW A|
|Stato di pubblicazione||Published - 2012|
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
Bellomo, B., Compagno, G., Lo Franco, R., Galve, F., Zambrini, R., Giorgi, G. L., & Lo Franco, R. (2012). Unified view of correlations using the square-norm distance. PHYSICAL REVIEW A, 85, 032104-1-032104-9.