3,580 research outputs found
Mixed Symmetry Solutions of Generalized Three-Particle Bargmann-Wigner Equations in the Strong-Coupling Limit
Starting from a nonlinear isospinor-spinor field equation, generalized
three-particle Bargmann-Wigner equations are derived. In the strong-coupling
limit, a special class of spin 1/2 bound-states are calculated. These solutions
which are antisymmetric with respect to all indices, have mixed symmetries in
isospin-superspin space and in spin orbit space. As a consequence of this mixed
symmetry, we get three solution manifolds. In appendix \ref{b}, table 2, these
solution manifolds are interpreted as the three generations of leptons and
quarks. This interpretation will be justified in a forthcoming paper.Comment: 17 page
Net Neutrality: An International Policy for the United States
Consider this scenario: Alex and John still are avid video game players and play hours a day, each connecting from the same town through different ISPs. However, since it is a peak Internet traffic time, it may be difficult for them to play. While Alex has the Diamond package from his ISP that ensures he has guaranteed high-bandwidth connection, John\u27s ISP does not offer anything other than regular residential service. John must compete with everyone else in his local area for bandwidth, including a few who constantly watch high-definition video-on-demand and subsequently constrain bandwidth for other users. Would it not be a great solution for John to buy a better package that would ensure that he has a guaranteed connection like Alex? Perhaps he could, but it might take a network that discriminates based upon traffic and that is decidedly not enshrined with network neutrality
Guided Proofreading of Automatic Segmentations for Connectomics
Automatic cell image segmentation methods in connectomics produce merge and
split errors, which require correction through proofreading. Previous research
has identified the visual search for these errors as the bottleneck in
interactive proofreading. To aid error correction, we develop two classifiers
that automatically recommend candidate merges and splits to the user. These
classifiers use a convolutional neural network (CNN) that has been trained with
errors in automatic segmentations against expert-labeled ground truth. Our
classifiers detect potentially-erroneous regions by considering a large context
region around a segmentation boundary. Corrections can then be performed by a
user with yes/no decisions, which reduces variation of information 7.5x faster
than previous proofreading methods. We also present a fully-automatic mode that
uses a probability threshold to make merge/split decisions. Extensive
experiments using the automatic approach and comparing performance of novice
and expert users demonstrate that our method performs favorably against
state-of-the-art proofreading methods on different connectomics datasets.Comment: Supplemental material available at
http://rhoana.org/guidedproofreading/supplemental.pd
Parallel generation of quadripartite cluster entanglement in the optical frequency comb
Scalability and coherence are two essential requirements for the experimental
implementation of quantum information and quantum computing. Here, we report a
breakthrough toward scalability: the simultaneous generation of a record 15
quadripartite entangled cluster states over 60 consecutive cavity modes
(Qmodes), in the optical frequency comb of a single optical parametric
oscillator. The amount of observed entanglement was constant over the 60
Qmodes, thereby proving the intrnisic scalability of this system. The number of
observable Qmodes was restricted by technical limitations, and we
conservatively estimate the actual number of similar clusters to be at least
three times larger. This result paves the way to the realization of large
entangled states for scalable quantum information and quantum computing.Comment: 4 pages + 7 supplemental-info pages, 6+1 figures, accepted by
Physical Review Letters. One minor revision to main text. One error corrected
in Eq. (18) of Supplemental informatio
Quadripartite continuous-variable entanglement via quadruply concurrent downconversion
We investigate an intra-cavity coupled down-conversion scheme to generate
quadripartite entanglement using concurrently resonant nonlinearities. We
verify that quadripartite entanglement is present in this system by calculating
the output fluctuation spectra and then considering violations of optimized
inequalities of the van Loock-Furusawa type. The entanglement characteristics
both above and below the oscillation threshold are considered. We also present
analytic solutions for the quadrature operators and the van Loock-Furusawa
correlations in the undepleted pump approximation.Comment: 9 pages, 5 figure
General approach for studying first-order phase transitions at low temperatures
By combining different ideas, a general and efficient protocol to deal with
discontinuous phase transitions at low temperatures is proposed. For small
's, it is possible to derive a generic analytic expression for appropriate
order parameters, whose coefficients are obtained from simple simulations. Once
in such regimes simulations by standard algorithms are not reliable, an
enhanced tempering method, the parallel tempering -- accurate for small and
intermediate system sizes with rather low computational cost -- is used.
Finally, from finite size analysis, one can obtain the thermodynamic limit. The
procedure is illustrated for four distinct models, demonstrating its power,
e.g., to locate coexistence lines and the phases density at the coexistence.Comment: 5 page
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