1,310 research outputs found
Gravitino Zero Modes on U(1)_R Strings
We consider theories with a spontaneously broken gauged R-symmetry, which can
only occur in supergravity models. These give rise to cosmic R-strings upon
which gravitino zero modes can exist. We construct solutions to the
Rarita-Schwinger spin-3/2 equation describing the gravitino in the field of
these cosmic strings and show that under some conditions these solutions may
give rise to gravitino currents on the string. We discuss further mathematical
and physical questions associated with these solutions.Comment: 18 pages, uses revte
A universal correction to higher spin entanglement entropy
We consider conformal field theories in 1+1 dimensions with W-algebra
symmetries, deformed by a chemical potential \mu for the spin-three current. We
show that the order \mu^2 correction to the Re'nyi and entanglement entropies
of a single interval in the deformed theory, on the infinite spatial line and
at finite temperature, is universal. The correction is completely determined by
the operator product expansion of two spin-three currents, and by the
expectation values of the stress tensor, its descendants and its composites,
evaluated on the n-sheeted Riemann surface branched along the interval. This
explains the recently found agreement of the order \mu^2 correction across
distinct free field CFTs and higher spin black hole solutions holographically
dual to CFTs with W-symmetry.Comment: Version accepted for publication as Rapid Communications in Phys.
Rev. D. Included an expanded discussion of the prescription used for contact
terms in relevant integrals; typos correcte
Epidemiology of Arrhythmias in Children
Unlike the adult population, arrhythmias occur less commonly in childhood. Only 5% of the emergency hospital admissions in the paediatric population is attributed to symptomatic arrhythmias. Majority of these tend to be accessory pathway mediated supraventricular tachyarrhythmias such as Wolff-Parkinson-White (WPW) syndrome, permanent junctional reciprocating tachycardia (PJRT) and Mahaim tachycardia. The non accessory pathway mediated supraventricular tachyarrhythmias commonly seen in children are junctional ectopic tachycardia (JET) and automatic ectopic atrial tachycardia (AET) and occur mostly in the post operative period after intracardiac repair for a structural heart defect. Ventricular tachycardia (VT) although uncommon, occurs in the paediatric age group in association with hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS) and Brugada syndrome. Occasionally, VT can also present symptomatically as incessant idiopathic infant ventricular tachycardia, right ventricular outflow tract tachycardia, benign VT, catecholaminic VT, idiopathic left ventricular tachycardia and in post cardiac surgical patients
Non-Equilibrium Production of Photons via \pi^0\to 2\gamma in DCC's
We study production of photons via the non-equilibrium relaxation of a
Disoriented Chiral Condensate with the chiral order parameter having a large
initial amplitude along the \pi^0 direction. Assuming the validity of the low
energy coupling of the neutral pion to photons via the U_A(1) anomalous vertex,
we find that for large initial amplitudes along the \pi^0 direction, photon
production is enhanced by parametric amplification. These processes are
non-perturbative with a large contribution during the non-equilibrium stages of
the evolution and result in a distinct distribution of the produced photons and
a polarization asymmetry. For initial amplitudes of the \pi^0 component of the
order parameter between 200-400 MeV, corresponding to energy densities between
1-12 GeV/fm^3 we find a peak in the photon distribution at energies between
\approx 300 -600 MeV. We also find polarization asymmetries typically between
5-10%. We discuss the potential experimental impact of these results as well as
the problems associated with its detection.Comment: 36 pages, 14 figures, uses revte
Ask the GRU: Multi-Task Learning for Deep Text Recommendations
In a variety of application domains the content to be recommended to users is
associated with text. This includes research papers, movies with associated
plot summaries, news articles, blog posts, etc. Recommendation approaches based
on latent factor models can be extended naturally to leverage text by employing
an explicit mapping from text to factors. This enables recommendations for new,
unseen content, and may generalize better, since the factors for all items are
produced by a compactly-parametrized model. Previous work has used topic models
or averages of word embeddings for this mapping. In this paper we present a
method leveraging deep recurrent neural networks to encode the text sequence
into a latent vector, specifically gated recurrent units (GRUs) trained
end-to-end on the collaborative filtering task. For the task of scientific
paper recommendation, this yields models with significantly higher accuracy. In
cold-start scenarios, we beat the previous state-of-the-art, all of which
ignore word order. Performance is further improved by multi-task learning,
where the text encoder network is trained for a combination of content
recommendation and item metadata prediction. This regularizes the collaborative
filtering model, ameliorating the problem of sparsity of the observed rating
matrix.Comment: 8 page
An open toss problem
We discuss some particular cases of the following problem. Each of m persons tosses
a coin. Those who get heads stay for the next round. Those who get tails are eliminated; however,
if all persons get tails in a round, they move to the next round (as if each of them had got a head).
The problem is to find the possibility that exactly one person is left after r rounds. All coins are
considered identical but not necessarily fair
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