17,899 research outputs found
Electroweak Sudakov Logarithms and Real Gauge-Boson Radiation in the TeV Region
Electroweak radiative corrections give rise to large negative,
double-logarithmically enhanced corrections in the TeV region. These are partly
compensated by real radiation and, moreover, affected by selecting
isospin-noninvariant external states. We investigate the impact of real gauge
boson radiation more quantitatively by considering different restricted final
state configurations. We consider successively a massive abelian gauge theory,
a spontaneously broken SU(2) theory and the electroweak Standard Model. We find
that details of the choice of the phase space cuts, in particular whether a
fraction of collinear and soft radiation is included, have a strong impact on
the relative amount of real and virtual corrections.Comment: 20 pages, 4 figure
Multiple Object Tracking in Urban Traffic Scenes with a Multiclass Object Detector
Multiple object tracking (MOT) in urban traffic aims to produce the
trajectories of the different road users that move across the field of view
with different directions and speeds and that can have varying appearances and
sizes. Occlusions and interactions among the different objects are expected and
common due to the nature of urban road traffic. In this work, a tracking
framework employing classification label information from a deep learning
detection approach is used for associating the different objects, in addition
to object position and appearances. We want to investigate the performance of a
modern multiclass object detector for the MOT task in traffic scenes. Results
show that the object labels improve tracking performance, but that the output
of object detectors are not always reliable.Comment: 13th International Symposium on Visual Computing (ISVC
Broadening the Scope of Nanopublications
In this paper, we present an approach for extending the existing concept of
nanopublications --- tiny entities of scientific results in RDF representation
--- to broaden their application range. The proposed extension uses English
sentences to represent informal and underspecified scientific claims. These
sentences follow a syntactic and semantic scheme that we call AIDA (Atomic,
Independent, Declarative, Absolute), which provides a uniform and succinct
representation of scientific assertions. Such AIDA nanopublications are
compatible with the existing nanopublication concept and enjoy most of its
advantages such as information sharing, interlinking of scientific findings,
and detailed attribution, while being more flexible and applicable to a much
wider range of scientific results. We show that users are able to create AIDA
sentences for given scientific results quickly and at high quality, and that it
is feasible to automatically extract and interlink AIDA nanopublications from
existing unstructured data sources. To demonstrate our approach, a web-based
interface is introduced, which also exemplifies the use of nanopublications for
non-scientific content, including meta-nanopublications that describe other
nanopublications.Comment: To appear in the Proceedings of the 10th Extended Semantic Web
Conference (ESWC 2013
Photonic qubits, qutrits and ququads accurately prepared and delivered on demand
Reliable encoding of information in quantum systems is crucial to all
approaches to quantum information processing or communication. This applies in
particular to photons used in linear optics quantum computing (LOQC), which is
scalable provided a deterministic single-photon emission and preparation is
available. Here, we show that narrowband photons deterministically emitted from
an atom-cavity system fulfill these requirements. Within their 500 ns coherence
time, we demonstrate a subdivision into d time bins of various amplitudes and
phases, which we use for encoding arbitrary qu-d-its. The latter is done
deterministically with a fidelity >95% for qubits, verified using a newly
developed time-resolved quantum-homodyne method.Comment: 5 pages, 4 figure
Certification of the Specific Micropore Volume and the Median Micropore Width of Two Microporous Reference Materials According to Draft-DIN 66135-4, BCR-704, BCR-705.
Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel
J/psi c\bar{c} production in e+e- and hadronic interactions
Predictions of the nonperturbative Quark Gluon Strings model based on the
1/N-expansion in QCD and string picture of interactions for production of
states containing heavy quarks are considered. Relations between fragmentation
functions for different states are used to predict the fragmentation function
of c-quark to J/psi-mesons. The resulting cross section for J/psi-production in
e+e- annihilation is in a good agreement with recent Belle result. It is argued
that associated production of c\bar{c} states with open charm should give a
substantial contribution to production of these states in hadronic interactions
at very high energies.Comment: 7 pages, 2 figure
Atom-photon entanglement generation and distribution
We extend an earlier model by Law {\it et al.} \cite{law} for a cavity QED
based single-photon-gun to atom-photon entanglement generation and
distribution. We illuminate the importance of a small critical atom number on
the fidelity of the proposed operation in the strong coupling limit. Our result
points to a promisingly high purity and efficiency using currently available
cavity QED parameters, and sheds new light on constructing quantum computing
and communication devices with trapped atoms and high Q optical cavities.Comment: 7 fig
Low-Temperature Orientation Dependence of Step Stiffness on {111} Surfaces
For hexagonal nets, descriptive of {111} fcc surfaces, we derive from
combinatoric arguments a simple, low-temperature formula for the orientation
dependence of the surface step line tension and stiffness, as well as the
leading correction, based on the Ising model with nearest-neighbor (NN)
interactions. Our formula agrees well with experimental data for both Ag and
Cu{111} surfaces, indicating that NN-interactions alone can account for the
data in these cases (in contrast to results for Cu{001}). Experimentally
significant corollaries of the low-temperature derivation show that the step
line tension cannot be extracted from the stiffness and that with plausible
assumptions the low-temperature stiffness should have 6-fold symmetry, in
contrast to the 3-fold symmetry of the crystal shape. We examine Zia's exact
implicit solution in detail, using numerical methods for general orientations
and deriving many analytic results including explicit solutions in the two
high-symmetry directions. From these exact results we rederive our simple
result and explore subtle behavior near close-packed directions. To account for
the 3-fold symmetry in a lattice gas model, we invoke a novel
orientation-dependent trio interaction and examine its consequences.Comment: 11 pages, 8 figure
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