780 research outputs found
Renormalized entropy of entanglement in relativistic field theory
Entanglement is defined between subsystems of a quantum system, and at fixed
time two regions of space can be viewed as two subsystems of a relativistic
quantum field. The entropy of entanglement between such subsystems is
ill-defined unless an ultraviolet cutoff is introduced, but it still diverges
in the continuum limit. This behaviour is generic for arbitrary finite-energy
states, hence a conceptual tension with the finite entanglement entropy typical
of nonrelativistic quantum systems. We introduce a novel approach to explain
the transition from infinite to finite entanglement, based on coarse graining
the spatial resolution of the detectors measuring the field state. We show that
states with a finite number of particles become localized, allowing an
identification between a region of space and the nonrelativistic degrees of
freedom of the particles therein contained, and that the renormalized entropy
of finite-energy states reduces to the entanglement entropy of nonrelativistic
quantum mechanics.Comment: 5 pages, 1 figur
The ridge effect and three-particle correlations
Pseudorapidity and azimuthal three-particle correlations are studied based on
a correlated-cluster model of multiparticle production. The model provides a
common framework for correlations in proton-proton and heavy-ion collisions
allowing easy comparison with the measurements. It is shown that azimuthal
cluster correlations are definitely required in order to understand
three-particle correlations in the near-side ridge effect. This is similar to
the explanation of the ridge phenomenon found in our previous analysis of
two-particle correlations and generalizes the model to higher-order
correlations.Comment: 16 pages, 7 figures. arXiv admin note: text overlap with
arXiv:1610.0640
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