137 research outputs found
Entanglement distribution revealed by macroscopic observations
What can we learn about entanglement between individual particles in
macroscopic samples by observing only the collective properties of the
ensembles? Using only a few experimentally feasible collective properties, we
establish an entanglement measure between two samples of spin-1/2 particles (as
representatives of two-dimensional quantum systems). This is a tight lower
bound for the average entanglement between all pairs of spins in general and is
equal to the average entanglement for a certain class of systems. We compute
the entanglement measures for explicit examples and show how to generalize the
method to more than two samples and multi-partite entanglement.Comment: 4 pages, 2 figures, revised and published versio
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