3,779 research outputs found
Estimating entanglement monotones with a generalization of the Wootters formula
Entanglement monotones, such as the concurrence, are useful tools to
characterize quantum correlations in various physical systems. The computation
of the concurrence involves, however, difficult optimizations and only for the
simplest case of two qubits a closed formula was found by Wootters [Phys. Rev.
Lett. 80, 2245 (1998)]. We show how this approach can be generalized, resulting
in lower bounds on the concurrence for higher dimensional systems as well as
for multipartite systems. We demonstrate that for certain families of states
our results constitute the strongest bipartite entanglement criterion so far;
moreover, they allow to recognize novel families of multiparticle bound
entangled states.Comment: 8 pages, one figure, v2: small change
Light vector meson and heavy baryon strong interaction
We calculate the coupling constants between the light vector mesons and heavy
baryons within the framework of the light-cone QCD sum rule in the leading
order of heavy quark effective theory. Most resulting sum rules are stable with
the variations of the Borel parameter and the continuum threshold. The
extracted couplings will be useful in the study of the possible heavy baryon
molecular states
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