Audenaert, K. M. R. and Plenio, M. B. (2006) When are correlations quantum? -- Verification and quantification of entanglement by simple measurements. New Journal of Physics, 8
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The verification and quantification of experimentally created entanglement by simple measurements, especially between distant particles, is an important basic task in quantum processing. When composite systems are subjected to local measurements the measurement data will exhibit correlations, whether these systems are classical or quantum. Therefore, the observation of correlations in the classical measurement record does not automatically imply the presence of quantum correlations in the system under investigation. In this work we explore the question of when correlations, or other measurement data, are sufficient to guarantee the existence of a certain amount of quantum correlations in the system and when additional information, such as the degree of purity of the system, is needed to do so. Various measurement settings are discussed, both numerically and analytically. Exact results and lower bounds on the least entanglement consistent with the observations are presented. The approach is suitable both for the bi-partite and the multi-partite setting.
This is a Submitted version This version's date is: 8/8/2006 This item is not peer reviewed
https://repository.royalholloway.ac.uk/items/37a878e7-a022-e43a-e4de-bf213475da07/6/
Deposited by Research Information System (atira) on 25-Jul-2012 in Royal Holloway Research Online.Last modified on 25-Jul-2012
10 pages and 4 figures, material and references added