4 research outputs found
Correlation-based entanglement criterion in bipartite multiboson systems
We describe a criterion for the detection of entanglement between two
multi-boson systems. The criterion is based on calculating correlations of
Gell-Mann matrices with a fixed boson number on each subsystem. This applies
naturally to systems such as two entangled spinor Bose-Einstein condensates. We
apply our criterion to several experimentally motivated examples, such as an entangled BECs, ac Stark shift induced two-mode squeezed BECs, and
photons under parametric down conversion. We find that entanglement can be
detected for all parameter regions for the most general criterion. Alternative
criteria based on a similar formalism are also discussed together with their
merits.Comment: 8 pages, 4 figures, journal versio
Unified approach to geometric and positive-map-based non-linear entanglement identifiers
Detecting quantumness of correlations (especially entanglement) is a very
hard task even in the simplest case i.e. two-partite quantum systems. Here we
provide an analysis whether there exists a relation between two most popular
types of entanglement identifiers: the first one based on positive maps and not
directly applicable in laboratory and the second one --- geometric entanglement
identifier which is based on specific Hermiticity-preserving maps. We show a
profound relation between those two types of entanglement criteria. Hereunder
we have proposed a general framework of nonlinear functional entanglement
identifiers which allows us to construct new experimentally friendly
entanglement criteria.Comment: 11 pages, 3 figure