title:
Proceedings of the Workshop on FORmal methods for the quantitative
  Evaluation of Collective Adaptive SysTems

abstract:
  Collective Adaptive Systems (CAS) consist of a large number of spatially
distributed heterogeneous entities with decentralised control and varying
degrees of complex autonomous behaviour that may be competing for shared
resources even when collaborating to reach common goals. It is important to
carry out thorough quantitative modelling and analysis and verification of
their design to investigate all aspects of their behaviour before they are put
into operation. This requires combinations of formal methods and applied
mathematics which moreover scale to large-scale CAS. The primary goal of
FORECAST is to raise awareness in the software engineering and formal methods
communities of the particularities of CAS and the design and control problems
which they bring.


title: Recent development in parton shower multijet merging

abstract:
  Higher order calculations are necessary to predict and describe measurements
in high energy collider physics. In recent years multiple approaches to combine
multiple next-to-leading (NLO) order corrections with parton showers had been
presented. We present on recent developments and future perspective. We
highlight similarities and ambiguities in the procedure of achieving a multijet
merging at NLO.


title: Tubelets: Unsupervised action proposals from spatiotemporal super-voxels

abstract:
  This paper considers the problem of localizing actions in videos as a
sequences of bounding boxes. The objective is to generate action proposals that
are likely to include the action of interest, ideally achieving high recall
with few proposals. Our contributions are threefold. First, inspired by
selective search for object proposals, we introduce an approach to generate
action proposals from spatiotemporal super-voxels in an unsupervised manner, we
call them Tubelets. Second, along with the static features from individual
frames our approach advantageously exploits motion. We introduce independent
motion evidence as a feature to characterize how the action deviates from the
background and explicitly incorporate such motion information in various stages
of the proposal generation. Finally, we introduce spatiotemporal refinement of
Tubelets, for more precise localization of actions, and pruning to keep the
number of Tubelets limited. We demonstrate the suitability of our approach by
extensive experiments for action proposal quality and action localization on
three public datasets: UCF Sports, MSR-II and UCF101. For action proposal
quality, our unsupervised proposals beat all other existing approaches on the
three datasets. For action localization, we show top performance on both the
trimmed videos of UCF Sports and UCF101 as well as the untrimmed videos of
MSR-II.


title: Hyperbolic rigidity of higher rank lattices

abstract:
  We prove that any action of a higher rank lattice on a Gromov-hyperbolic
space is elementary. More precisely, it is either elliptic or parabolic. This
is a large generalization of the fact that any action of a higher rank lattice
on a tree has a fixed point. A consequence is that any quasi-action of a higher
rank lattice on a tree is elliptic, i.e. it has Manning's property (QFA).
Moreover, we obtain a new proof of the theorem of Farb-Kaimanovich-Masur that
any morphism from a higher rank lattice to a mapping class group has finite
image, without relying on the Margulis normal subgroup theorem nor on bounded
cohomology. More generally, we prove that any morphism from a higher rank
lattice to a hierarchically hyperbolic group has finite image. In the Appendix,
Vincent Guirardel and Camille Horbez deduce rigidity results for morphisms from
a higher rank lattice to various outer automorphism groups.


title:
Working Locally Thinking Globally - Part I: Theoretical Guarantees for
  Convolutional Sparse Coding

abstract:
  The celebrated sparse representation model has led to remarkable results in
various signal processing tasks in the last decade. However, despite its
initial purpose of serving as a global prior for entire signals, it has been
commonly used for modeling low dimensional patches due to the computational
constraints it entails when deployed with learned dictionaries. A way around
this problem has been proposed recently, adopting a convolutional sparse
representation model. This approach assumes that the global dictionary is a
concatenation of banded Circulant matrices. Although several works have
presented algorithmic solutions to the global pursuit problem under this new
model, very few truly-effective guarantees are known for the success of such
methods. In the first of this two-part work, we address the theoretical aspects
of the sparse convolutional model, providing the first meaningful answers to
corresponding questions of uniqueness of solutions and success of pursuit
algorithms. To this end, we generalize mathematical quantities, such as the
$\ell_0$ norm, the mutual coherence and the Spark, to their counterparts in the
convolutional setting, which intrinsically capture local measures of the global
model. In a companion paper, we extend the analysis to a noisy regime,
addressing the stability of the sparsest solutions and pursuit algorithms, and
demonstrate practical approaches for solving the global pursuit problem via
simple local processing.


title: A sharp bound on the Lebesgue constant for Leja points in the unit disk

abstract:
  We give a sharp bound for the Lebesgue constant associated to Leja sequences
in the complex unit disk, confirming a conjecture made by Calvi and Phung in
2011


title: Optimal convection cooling flows in general geometries

abstract:
  We generalize a recent method for computing optimal 2D convection cooling
flows in a horizontal layer to a wide range of geometries, including those
relevant for technological applications. We write the problem in a conformal
pair of coordinates which are the pure conduction temperature and its harmonic
conjugate. We find optimal flows for cooling a cylinder in an annular domain, a
hot plate embedded in a cold surface, and a channel with hot interior and cold
exterior. With a constraint of fixed kinetic energy, the optimal flows are all
essentially the same in the conformal coordinates. In the physical coordinates,
they consist of vortices ranging in size from the length of the hot surface to
a small cutoff length at the interface of the hot and cold surfaces. With the
constraint of fixed enstrophy (or fixed rate of viscous dissipation), a
geometry-dependent metric factor appears in the equations. The conformal
coordinates are useful here because they map the problems to a rectangular
domain, facilitating numerical solutions. With a small enstrophy budget, the
optimal flows are dominated by vortices which have the same size as the flow
domain.


title: Signatures of Steady Heating in Time Lag Analysis of Coronal Emission

abstract:
  Among the many ways of investigating coronal heating, the time lag method of
Viall & Klimchuk (2012) is becoming increasingly prevalent as an analysis
technique complementary to those traditionally used. The time lag method cross
correlates light curves at a given spatial location obtained in spectral bands
that sample different temperature plasmas. It has been used most extensively
with data from the Atmospheric Imaging Assembly on the Solar Dynamics
Observatory. We have previously applied the time lag method to entire active
regions and surrounding quiet Sun and create maps of the results (Viall &
Klimchuk 2012; Viall & Klimchuk 2015). We find that the majority of time lags
are consistent with the cooling of coronal plasma that has been impulsively
heated. Additionally, a significant fraction of the map area has a time lag of
zero. This does not indicate a lack of variability. Rather, strong variability
must be present, and it must occur in phase in the different channels. We have
shown previously that these zero time lags are consistent with the transition
region response to coronal nanoflares (Viall & Klimchuk 2015; Bradshaw & Viall
2016), but other explanations are possible. A common misconception is that the
zero time lag indicates steady emission resulting from steady heating. Using
simulated and observed light curves, we demonstrate here that highly correlated
light curves at zero time lag are not compatible with equilibrium solutions.
Such light curves can only be created by evolution.


title:
Working Locally Thinking Globally - Part II: Stability and Algorithms
  for Convolutional Sparse Coding

abstract:
  The convolutional sparse model has recently gained increasing attention in
the signal and image processing communities, and several methods have been
proposed for solving the pursuit problem emerging from it -- in particular its
convex relaxation, Basis Pursuit. In the first of this two-part work, we have
provided a theoretical back-bone for this model, providing guarantees for the
uniqueness of the sparsest solution and for the success of pursuit algorithms
by introducing the notion of stripe sparsity and other related measures.
Herein, we extend the analysis to a noisy regime, thereby considering signal
perturbations and model deviations. We address questions of stability of the
sparsest solutions and the success of pursuit algorithms, both greedy and
convex. Classical definitions such as the RIP are generalized to the
convolutional model, and existing notions such as the ERC are connected to our
setting. On the algorithmic side, we demonstrate how to solve the global
pursuit problem by using simple local processing, thus offering a first of its
kind bridge between global modeling of signals and their patch-based local
treatment.


title:
Topological invariance of the Collet-Eckmann condition for
  one-dimensional maps

abstract:
  This paper is devoted to study the topological invariance of several
non-uniform hyperbolicity conditions of one-dimensional maps. In contrast with
the case of maps with only one critical point, it is known that for maps with
several critical points the Collet-Eckmann condition is not in itself
invariance under topological conjugacy. We show that the Collet-Eckmann
condition together with any of several slow recurrence conditions is invariant
under topological conjugacy. This extends and gives a new proof of a result by
Luzzatto and Wang that also applies to the complex setting.


title: Kernel Bayesian Inference with Posterior Regularization

abstract:
  We propose a vector-valued regression problem whose solution is equivalent to
the reproducing kernel Hilbert space (RKHS) embedding of the Bayesian posterior
distribution. This equivalence provides a new understanding of kernel Bayesian
inference. Moreover, the optimization problem induces a new regularization for
the posterior embedding estimator, which is faster and has comparable
performance to the squared regularization in kernel Bayes' rule. This
regularization coincides with a former thresholding approach used in kernel
POMDPs whose consistency remains to be established. Our theoretical work solves
this open problem and provides consistency analysis in regression settings.
Based on our optimizational formulation, we propose a flexible Bayesian
posterior regularization framework which for the first time enables us to put
regularization at the distribution level. We apply this method to nonparametric
state-space filtering tasks with extremely nonlinear dynamics and show
performance gains over all other baselines.


title:
Analysis of the Very Inner Milky Way Dark Matter Distribution and
  Gamma-Ray Signals

abstract:
  We analyze the possibility that the HESS gamma-ray source at the Galactic
Center could be explained as the secondary flux produced by annihilation of TeV
Dark Matter (TeVDM) particles with locally enhanced density, in a region
spatially compatible with the HESS observations themselves. We study the inner
100 pc considering (i) the extrapolation of several density profiles from
state-of-the-art N-body + Hydrodynamics simulations of Milky Way-like galaxies,
(ii) the DM spike induced by the black hole, and (iii) the DM particles
scattering off by bulge stars. We show that in some cases the DM spike may
provide the enhancement in the flux required to explain the cut-off in the HESS
J1745-290 gamma-ray spectra as TeVDM. In other cases, it may helps to describe
the spatial tail reported by HESS II at angular scales < 0.54 degrees towards
Sgr A.

categories: astro-ph.HE astro-ph.CO astro-ph.IM hep-ph


title: Waveguide metacouplers for in-plane polarimetry

abstract:
  The state of polarization (SOP) is an inherent property of the vectorial
nature of light and a crucial parameter in a wide range of remote sensing
applications. Nevertheless, the SOP is rather cumbersome to probe
experimentally, as conventional detectors only respond to the intensity of the
light, hence loosing the phase information between orthogonal vector
components. In this work, we propose a new type of polarimeter that is compact
and well-suited for in-plane optical circuitry, while allowing for immediate
determination of the SOP through simultaneous retrieval of the associated
Stokes parameters. The polarimeter is based on plasmonic phase-gradient
birefringent metasurfaces that facilitate normal incident light to launch
in-plane photonic waveguide modes propagating in six predefined directions with
the coupling efficiencies providing a direct measure of the incident SOP. The
functionality and accuracy of the polarimeter, which essentially is an
all-polarization sensitive waveguide metacoupler, is confirmed through
full-wave simulations at the operation wavelength of 1.55$\mu$m.


title: Computationally Efficient Covert Communication

abstract:
  In this paper, we design the first computationally efficient codes for
simultaneously reliable and covert communication over Binary Symmetric Channels
(BSCs). Our setting is as follows: a transmitter Alice wishes to potentially
reliably transmit a message to a receiver Bob, while ensuring that the
transmission taking place is covert with respect to an eavesdropper Willie (who
hears Alice's transmission over a noisier BSC). Prior works show that Alice can
reliably and covertly transmit O(\sqrt{n}) bits over n channel uses without any
shared secret between Alice and Bob. One drawback of prior works is that the
computational complexity of the codes designed scales as 2^{\Theta(\sqrt{n})}.
In this work we provide the first computationally tractable codes with provable
guarantees on both reliability and covertness, while simultaneously achieving
the best known throughput for the problem.


title:
Extending the Nanbu Collision Algorithm to Non-Spitzer Systems and
  Application to Laser Heating and Damage

abstract:
  We have generalized the Nanbu collision algorithm to accommodate arbitrary
collision rates, enabling accurate kinetic modeling of short range particle
interactions in non-Spitzer systems. With this extension, we explore the effect
of different collision models on the simulation of how ultra-intense lasers
first begin to heat a target. The effect of collisions on plasma evolution is
crucial for treating particle slowing, energy transport, and thermalization.
The widely used Nanbu collision algorithm provides a fast and computationally
efficient method to include the effects of collisions between charged particles
in kinetic simulations without requiring that the particles already be in local
thermal equilibrium. However, it is "hardwired" to use Spitzer collision rates
appropriate for hot, relatively dilute plasmas. This restriction prevents the
Nanbu collision algorithm from accurately describing the initial heating of a
cold target, a key problem for the study of laser damage or the generation of
the warm dense matter state. We describe our approach for modifying the Nanbu
collision algorithm and demonstrate the improved accuracy for copper targets.


title:
Numeric Deduction in Symbolic Computation. Application to Normalizing
  Transformations

abstract:
  Algorithms of numeric (in exact arithmetic) deduction of analytical
expressions, proposed and described by Shevchenko and Vasiliev (1993), are
developed and implemented in a computer algebra code. This code is built as a
superstructure for the computer algebra package by Shevchenko and Sokolsky
(1993a) for normalization of Hamiltonian systems of ordinary differential
equations, in order that high complexity problems of normalization could be
solved. As an example, a resonant normal form of a Hamiltonian describing the
hyperboloidal precession of a dynamically symmetric satellite is derived by
means of the numeric deduction technique. The technique provides a considerable
economy, about 30 times in this particular application, in computer memory
consumption. It is naturally parallelizable. Thus the economy of memory
consumption is convertible into a gain in computation speed.


title: Detection of periodicity in functional time series

abstract:
  We derive several tests for the presence of a periodic component in a time
series of functions. We consider both the traditional setting in which the
periodic functional signal is contaminated by functional white noise, and a
more general setting of a contaminating process which is weakly dependent.
Several forms of the periodic component are considered. Our tests are motivated
by the likelihood principle and fall into two broad categories, which we term
multivariate and fully functional. Overall, for the functional series that
motivate this research, the fully functional tests exhibit a superior balance
of size and power. Asymptotic null distributions of all tests are derived and
their consistency is established. Their finite sample performance is examined
and compared by numerical studies and application to pollution data.


title: Mapping Data to Ontologies with Exceptions Using Answer Set Programming

abstract:
  In ontology-based data access, databases are connected to an ontology via
mappings from queries over the database to queries over the ontology. In this
paper, we consider mappings from relational databases to first-order
ontologies, and define an ASP-based framework for GLAV mappings with queries
over the ontology in the mapping rule bodies. We show that this type of
mappings can be used to express constraints and exceptions, as well as being a
powerful mechanism for succinctly representing OBDA mappings. We give an
algorithm for brave reasoning in this setting, and show that this problem has
either the same data complexity as ASP (NP- complete), or it is at least as
hard as the complexity of checking entailment for the ontology queries.
Furthermore, we show that for ontologies with UCQ-rewritable queries there
exists a natural reduction from mapping programs to \exists-ASP, an extension
of ASP with existential variables that itself admits a natural reduction to
ASP.


title:
Perrin-Riou's main conjecture for elliptic curves at supersingular
  primes

abstract:
  In 1987, B. Perrin-Riou formulated a Heegner point main conjecture for
elliptic curves at primes of ordinary reduction. In this paper, we formulate an
analogue of Perrin-Riou's main conjecture for supersingular primes. We then
prove this conjecture under mild hypotheses, and deduce from this result a
$\Lambda$-adic extension of Kobayashi's $p$-adic Gross-Zagier formula, new
cases of B.-D. Kim's doubly-signed main conjectures, and a strengthened version
of Skinner's converse to the Gross-Zagier-Kolyvagin theorem for supersingular
primes.


title:
A Functional Complexity Framework for the Analysis of Telecommunication
  Networks

abstract:
  The rapid evolution of network services demands new paradigms for studying
and designing networks. In order to understand the underlying mechanisms that
provide network functions, we propose a framework which enables the functional
analysis of telecommunication networks. This framework allows us to isolate and
analyse a network function as a complex system. We propose functional
topologies to visualise the relationships between system entities and enable
the systematic study of interactions between them. We also define a complexity
metric $C_F$ (functional complexity) which quantifies the variety of structural
patterns and roles of nodes in the topology. This complexity metric provides a
wholly new approach to study the operation of telecommunication networks. We
study the relationship between $C_F$ and different graph structures by
analysing graph theory metrics in order to recognize complex organisations.
$C_F$ is equal to zero for both a full mesh topology and a disconnected
topology. We show that complexity is very high for a dense structure that shows
high integration (shorter average path length and high average clustering
coefficient). We make a connection between functional complexity, robustness
and response to changes that may appear in the system configuration. We also
make a connection between the implementation and the outcome of a network
function which correlates the characteristics of the outcome with the complex
relationships that underpin the functional structure.


title:
Self-consistent Bogoliubov de Gennes theory of the vortex lattice state
  in a two-dimensional strong type-II superconductor at high magnetic fields

abstract:
  A self-consistent Bogoliubov deGennes theory of the vortex lattice state in a
2D strong type-II superconductor at high magnetic fields reveals a novel
quantum mixed state around the semiclassical Hc2, characterized by a
well-defined Landau--Bloch band structure in the quasi-particle spectrum and
suppressed order-parameter amplitude, which sharply crossover into the
well-known semiclassical (Helfand-Werthamer) results upon decreasing magnetic
field. Application to the 2D superconducting state observed recently on the
surface of the topological insulator Sb2Te3, accounts well for the experimental
data, revealing a strong type-II superconductor, with unusually low carrier
density and very small cyclotron mass, which can be realized only in the strong
coupling superconductor limit.


title:
Reply to "Comment on Generalized Exclusion Processes: Transport
  Coefficients"

abstract:
  We reply to the comment of Becker, Nelissen, Cleuren, Partoens, and Van den
Broeck, Phys. Rev. E 93, 046101 (2016) on our article, Phys. Rev. E 90, 052108
(2014) about transport properties of a class of generalized exclusion
processes.


title: Hamiltonian Coupling of Electromagnetic Field and Matter

abstract:
  Reversible part of evolution equations of physical systems is often generated
by a Poisson bracket. We discuss geometric means of construction of Poisson
brackets and their mutual coupling (direct, semidirect and matched-pair
products) as well as projections of Poisson brackets to less detailed Poisson
brackets. This way the Hamiltonian coupling between transport of mixtures and
electrodynamics is elucidated.


title: Mini-Batch Spectral Clustering

abstract:
  The cost of computing the spectrum of Laplacian matrices hinders the
application of spectral clustering to large data sets. While approximations
recover computational tractability, they can potentially affect clustering
performance. This paper proposes a practical approach to learn spectral
clustering based on adaptive stochastic gradient optimization. Crucially, the
proposed approach recovers the exact spectrum of Laplacian matrices in the
limit of the iterations, and the cost of each iteration is linear in the number
of samples. Extensive experimental validation on data sets with up to half a
million samples demonstrate its scalability and its ability to outperform
state-of-the-art approximate methods to learn spectral clustering for a given
computational budget.


title: Submaximally Symmetric Almost Quaternionic Structures

abstract:
  The symmetry dimension of a geometric structure is the dimension of its
symmetry algebra. We investigate symmetries of almost quaternionic structures
of quaternionic dimension $n$. The maximal possible symmetry is realized by the
quaternionic projective space $\mathbb{H}P^n$, which is flat and has the
symmetry algebra $\mathfrak{sl}(n+1,\mathbb{H})$ of dimension $4n^2+8n+3$. For
non-flat almost quaternionic manifolds we compute the next biggest (submaximal)
symmetry dimension. We show that it is equal to $4n^2-4n+9$ for $n>1$ (it is
equal to 8 for $n=1$). This is realized both by a quaternionic structure
(torsion--free) and by an almost quaternionic structure with vanishing
quaternionic Weyl curvature.


title:
Nuclear shape phase transition within a conjonction of {\gamma}-rigid
  and {\gamma}-stable collective behaviours in deformation dependent mass
  formalism

abstract:
  In this paper, we present a theoretical study of a conjonction of
$\gamma$-rigid and $\gamma$-stable collective motions in critical point
symmetries of the phase transitions from spherical to deformed shapes of nuclei
using exactly separable version of the Bohr Hamiltonian with
deformation-dependent mass term. The deformation-dependent mass is applied
simultaneously to $\gamma$-rigid and $\gamma$-stable parts of this famous
collective Hamiltonian. Moreover, the $\beta$ part of the problem is described
by means of Davidson potential, while the $\gamma$-angular part corresponding
to axially symmetric shapes is treated by a Harmonic Osillator potential. The
energy eigenvalues and normalized eigenfunctions of the problem are obtained in
compact forms by making use of the asymptotic iteration method. The combined
effect of the deformation-dependent mass and rigidity as well as harmonic
oscillator stiffness parameters on the energy spectrum and wave functions is
duly investigated. Also, the electric quadrupole transition ratios and energy
sprectrum of some $\gamma$-stable and prolate nuclei are calculated and
compared with the experimental data as well as with other theoretical models.


title:
On semi-exclusive measurement of $\gamma\gamma\to\gamma\gamma$
  scattering

abstract:
  The two-photon production of photon pairs, i.e. the
$\gamma\gamma\to\gamma\gamma$ process, is studied. Different production modes
regarding the elastic or inelastic coupling of the intermediate-state photons
to the protons are considered. The semi-exclusive measurement, where one intact
proton is registered by a dedicated forward proton detector, is discussed. As
an example, the signal and background simulations are performed for the
$\gamma\gamma\to\gamma\gamma$ process mediated by the hypothetical 750 GeV
resonance.


title:
Artificial neural networks and fuzzy logic for recognizing alphabet
  characters and mathematical symbols

abstract:
  Optical Character Recognition software (OCR) are important tools for
obtaining accessible texts. We propose the use of artificial neural networks
(ANN) in order to develop pattern recognition algorithms capable of recognizing
both normal texts and formulae. We present an original improvement of the
backpropagation algorithm. Moreover, we describe a novel image segmentation
algorithm that exploits fuzzy logic for separating touching characters.


title:
Effect of plasmonic near field on the emittance of plasmon-enhanced
  photocathode

abstract:
  The introduction of the surface plasmon polarizations makes the emittance of
the photocathode complicated. In this paper, the emittance of plasmon-enhanced
photocathode is analyzed. It is first demonstrated that the plasmonic near
field can increase the emittance of the plasmon-enhanced photocathode. A
simulation method has been used to estimate the emittance caused by plasmonic
near field, and the suppression method also has been discussed, both of which
are significant for the design of high performance plasmon-enhanced
photocathode.


title: Critical $O(N)$ models in the complex field plane

abstract:
  Local and global scaling solutions for $O(N)$ symmetric scalar field theories
are studied in the complexified field plane with the help of the
renormalisation group. Using expansions of the effective action about small,
large, and purely imaginary fields, we obtain and solve exact recursion
relations for all couplings and determine the $3d$ Wilson-Fisher fixed point
analytically. For all $O(N)$ universality classes, we further establish that
Wilson-Fisher fixed point solutions display singularities in the complex field
plane, which dictate the radius of convergence for real-field expansions of the
effective action. At infinite $N$, we find closed expressions for the
convergence-limiting singularities and prove that local expansions of the
effective action are powerful enough to uniquely determine the global
Wilson-Fisher fixed point for any value of the fields. Implications of our
findings for interacting fixed points in more complicated theories are
indicated.


title: Parabolic induction and extensions

abstract:
  Let $G$ be a $p$-adic reductive group. We determine the extensions between
admissible smooth mod $p$ representations of $G$ parabolically induced from
supersingular representations of Levi subgroups of $G$, in terms of extensions
between representations of Levi subgroups of $G$ and parabolic induction. This
proves for the most part a conjecture formulated by the author in a previous
article and gives some strong evidence for the remaining part. In order to do
so, we use the derived functors of the left and right adjoints of the parabolic
induction functor, both related to Emerton's $\delta$-functor of derived
ordinary parts. We compute the latter on parabolically induced representations
of $G$ by pushing to their limits the methods initiated and expanded by the
author in previous articles.


title: $K_2$ of Kac-Moody Groups

abstract:
  Ulf Rehmann and Jun Morita, in their 1989 paper "A Matsumoto-type theorem for
Kac-Moody groups", gave a presentation of $K_2(A,F)$ for any generalised Cartan
matrix $A$ and field $F$. The purpose of this paper is to use this presentation
to compute $K_2(A,F)$ more explicitly in the case when $A$ is hyperbolic. In
particular, we shall show that these $K_2(A,F)$ can always be expressed as a
product of quotients of $K_2(F)$ and $K_2(2,F)$. Along the way, we shall also
prove a similar result in the case when $A$ has an odd entry in each column.


title:
Measurement of the inelastic proton-proton cross section at $\sqrt{s}$ =
  13 TeV

abstract:
  A measurement of the inelastic proton-proton cross section at a
centre-of-mass energy of $\sqrt{s}$ = 13 TeV is presented. The analysis is
performed using the CMS detector, in particular with information from forward
calorimetry at pseudorapidities of 3.0 < {\eta} < 5.2 and -6.6 < {\eta} < -3.0.
A visible cross section is measured in two different detector acceptances and
finally extrapolated to the full inelastic phase space domain. The results are
compared with those of other experiments, and with models used to describe
high-energy hadronic interactions.


title: Low temperature Hall effect in bismuth chalcogenides thin films

abstract:
  Bismuth chalcogenides are the most studied 3D topological insulators. As a
rule, at low temperatures thin films of these materials demonstrate positive
magnetoresistance due to weak antilocalization. Weak antilocalization should
lead to resistivity decrease at low temperatures; in experiments, however,
resistivity grows as temperature decreases. From transport measurements for
several thin films (with various carrier density, thickness, and carrier
mobility), and by using purely phenomenological approach, with no microscopic
theory, we show that the low temperature growth of the resistivity is
accompanied by growth of the Hall coefficient, in agreement with diffusive
electron-electron interaction correction mechanism. Our data reasonably explain
the low-temperature resistivity upturn.


title: Secular resonances with Ceres and Vesta

abstract:
  In this work we explore dynamical perturbations induced by the massive
asteroids Ceres and Vesta on main-belt asteroids through secular resonances.
First we determine the location of the linear secular resonances with Ceres and
Vesta in the main belt, using a purely numerical technique. Then we use a set
of numerical simulations of fictitious asteroids to investigate the importance
of these secular resonances in the orbital evolution of main-belt asteroids. We
found, evaluating the magnitude of the perturbations in the proper elements of
the test particles, that in some cases the strength of these secular resonances
is comparable to that of known non-linear secular resonances with the giant
planets. Finally we explore the asteroid families that are crossed by the
secular resonances we studied, and identified several cases where the latter
seem to play an important role in their post-impact evolution.


title:
On the volume measure of non-smooth spaces with Ricci curvature bounded
  below

abstract:
  We prove that, given an $RCD^{*}(K,N)$-space $(X,d,m)$, then it is possible
to $m$-essentially cover $X$ by measurable subsets $(R_{i})_{i\in \mathbb{N}}$
with the following property: for each $i$ there exists $k_{i} \in
\mathbb{N}\cap [1,N]$ such that $m\llcorner R_{i}$ is absolutely continuous
with respect to the $k_{i}$-dimensional Hausdorff measure. We also show that a
Lipschitz differentiability space which is bi-Lipschitz embeddable into a
euclidean space is rectifiable as a metric measure space, and we conclude with
an application to Alexandrov spaces.


title:
Refinement of the Equilibrium of Public Goods Games over Networks:
  Efficiency and Effort of Specialized Equilibria

abstract:
  Recently Bramoulle and Kranton presented a model for the provision of public
goods over a network and showed the existence of a class of Nash equilibria
called specialized equilibria wherein some agents exert maximum effort while
other agents free ride. We examine the efficiency, effort and cost of
specialized equilibria in comparison to other equilibria. Our main results show
that the welfare of a particular specialized equilibrium approaches the maximum
welfare amongst all equilibria as the concavity of the benefit function tends
to unity. For forest networks a similar result also holds as the concavity
approaches zero. Moreover, without any such concavity conditions, there exists
for any network a specialized equilibrium that requires the maximum weighted
effort amongst all equilibria. When the network is a forest, a specialized
equilibrium also incurs the minimum total cost amongst all equilibria. For
well-covered forest networks we show that all welfare maximizing equilibria are
specialized and all equilibria incur the same total cost. Thus we argue that
specialized equilibria may be considered as a refinement of the equilibrium of
the public goods game. We show several results on the structure and efficiency
of equilibria that highlight the role of dependants in the network.


title:
Multiparticle correlation expansion of relative entropy in lattice
  systems

abstract:
  This paper deals with the construction of the multiparticle correlation
expansion of relative entropy for lattice systems. Thanks to this analysis we
are able to express the statistical distance between two systems as a series
built over clusters of increasing dimension. Each addend is written in terms of
correlation functions and expresses the contribution to the relative entropy
due to structural information inside the selected cluster. We present a general
procedure for the explicit construction of all the terms of the series. As a
first application of this result, we show that the coefficients of the
multiparticle correlation expansion of the excess entropy can be computed from
our formula, as a particular case.


title: Rigid cylindrical frameworks with two coincident points

abstract:
  We develop a rigidity theory for frameworks in $\mathbb{R}^3$ which have two
coincident points but are otherwise generic and only infinitesimal motions
which are tangential to a family of cylinders induced by the realisation are
considered. We then apply our results to show that vertex splitting, under the
additional assumption that the new edge is redundant, preserves the property of
being generically globally rigid on families of concentric cylinders.


title: Universal scaling of gluon and ghost propagators in the infrared

abstract:
  A universal behavior is predicted for ghost and gluon propagators in the
infrared. The universal behavior is shown to be a signature of a one-loop
approximation and emerges naturally by the massive expansion that predicts
universal analytical functions for the inverse dressing functions that do not
depend on any parameter or color number. By a scaling of units and by adding an
integration constant, all lattice data, for different color numbers (and even
quark content for the ghosts), collapse on the same universal curves predicted
by the massive expansion.


title:
Pointwise convergence of almost periodic Fourier series and associated
  series of dilates

abstract:
  Let $\mathcal S^2$ be the Stepanov space and let $ \lambda_n\uparrow\infty$.
Let $(a_n)_{n\ge 1}$ be satisfying Wiener's condition $A:= \sum_{n\ge 1}
\big(\sum_{k\, :\, n\le \lambda_k \le n+1}|a_k|\big)^2 <\infty$. We prove that
$\big\| \sup_{N\ge 1} \big|\sum_{n=1}^Na_n{\rm e}^{i\lambda_n t}\big| \,
\big\|_{\mathcal S^2}\le C\, A^{1/2} $ where $C>0$ denotes a universal
constant. Moreover, the series $\sum_{n\ge 1} a_n{\rm e}^{it\lambda_n }$
converges for $\lambda$-a.e. $t\in \mathbb R$. This contains as a special case
Hedenmalm and Saksman result for Dirichlet series. We also obtain maximal
inequalities for corresponding series of dilates. Let $1\le p,q\le 2$ be such
that $1/p+1/q=3/2$. Then for any sequence $(\alpha_n)_{n\ge 1}$ and
$(\beta_n)_{n\ge 1}$ of complex numbers such that $K:=\sum_{n\ge 1}
\big(\sum_{k\,:\, n\le \lambda_k< n+1}|\alpha_k|\,\big)^p <\infty$ and
$L:=\sum_{n\ge 1} \big(\sum_{k\,:\, n\le \mu_k< n+1} |\beta_k|\,\big)^q
<\infty$, we have $$ \Big\|\sup_{N\ge 1} \big|\sum_{n=1}^N \alpha_n D(\lambda_n
t)\big|\, \Big\|_{\mathcal S^2} \le C\, K^{1/p}\, L^{1/q }
  $$ where $D(t)= \sum_{n\ge 1}\beta_n {\rm e}^{i\mu_n t}$ is defined in
$\mathcal S^2$. Moreover, the series $\sum_{n\ge 1} \alpha_n D(\lambda_nt)$
converges in $\mathcal S^2$ and for $\lambda$-a.e. $t\in \mathbb R$. We further
show that if $\{\lambda_k, k\ge 1\}$ satisfies the following condition $$\sum_{
k\not=\ell\,,\, k'\not=\ell'\atop
(k,\ell)\neq(k',\ell')}\big(1-|(\lambda_k-\lambda_\ell)-(\lambda_{k'}-\lambda_{\ell'})
|\big)_+^2 \, <\infty,$$ then the series $\sum_{k} a_k {\rm e}^{i\lambda_kt}$
converges on a set of positive Lebesgue measure, only if the series
$\sum_{k=1}^\infty |a_k|^2$ converges. The above condition is in particular
fulfilled when $\{\lambda_k, k\ge 1\}$ is a Sidon sequence.


title:
Damping of Alfven waves by Turbulence and its Consequences: from
  Cosmic-Rays Streaming to Launching Winds

abstract:
  This paper considers turbulent damping of Alfven waves in magnetized plasmas.
We identify two cases of damping, one related to damping of cosmic rays
streaming instability, the other related to damping of Alfven waves emitted by
a macroscopic wave source, e.g. stellar atmosphere. The physical difference
between the two cases is that in the former case the generated waves are
emitted in respect to the local direction of magnetic field, in the latter in
respect to the mean field. The scaling of damping is different in the two
cases. We the regimes of turbulence ranging from subAlfvenic to superAlfvenic
we obtain analytical expressions for the damping rates and define the ranges of
applicability of these expressions. Describing the damping of the streaming
instability, we find that for subAlfvenic turbulence the range of cosmic ray
energies influenced by weak turbulence is unproportionally large compared to
the range of scales that the weak turbulence is present. On the contrary, the
range of cosmic ray energies affected by strong Alfvenic turbulence is rather
limited. A number of astrophysical applications of the process ranging from
launching of stellar and galactic winds to propagation of cosmic rays in
galaxies and clusters of galaxies is considered. In particular, we discuss how
to reconcile the process of turbulent damping with the observed isotropy of the
Milky Way cosmic rays.


title: Jets of SS433 on scales of dozens parsecs

abstract:
  The radio nebula W50 harbours the relativistic binary system SS433, which is
a source of the powerful wind and jets. The origin of W50 is wrapped in the
interplay of the wind, supernova remnant and jets. The evolution of the jets on
the scales of the nebula is a Rosetta stone for its origin. To disentangle the
roles of these components, we study physical conditions of the jets propagation
inside W50, and determine deceleration of the jets. The morphology and
parameters of the interior of W50 are analyzed using the available observations
of the eastern X-ray lobe, which traces the jet. In order to estimate
deceleration of this jet, we devised a simplistic model of the viscous
interaction, via turbulence, of a jet with the ambient medium, which would fit
mass entrainment from the ambient medium into the jets of the radio galaxy
3C31, the well studied case of continuously decelerating jets. X-ray
observations suggest that the eastern jet persists through W50 as hollow one,
and is recollimated to the opening $\sim 30^\circ$. From the thermal emission
of the eastern X-ray lobe, we determine a pressure of $P \sim 3\cdot 10^{-11}$
erg/cm$^3$ inside W50. In the frame of a theory of the dynamics of radiative
supernova remnants and stellar wind bubbles, this pressure in combination with
other known parameters restricts W50's origin to a supernova happened $\sim
100\,000$ yr ago. Also, this pressure in our entrainment model gives a
deceleration of the jet by $\sim 60\%$ in the bounds of W50's spherical
component, of radius $\sim 40$ pc. In this case, the age of the jet should be
$\ll 27\,000$ yr so as to satisfy the sphericity of W50. The entrainment model
comes to the viscous stress in a jet of a form $\sigma = \alpha P$, where the
viscosity parameter $\alpha$ is predefined by the model.


title: Proof of de Smit's conjecture: a freeness criterion

abstract:
  Let $A\to B$ be a morphism of Artin local rings with the same embedding
dimension. We prove that any $A$-flat $B$-module is $B$-flat. This freeness
criterion was conjectured by de Smit in 1997 and improves Diamond's Theorem 2.1
from his 1997 paper "The Taylor-Wiles construction and multiplicity one". We
also prove that if there is a nonzero $A$-flat $B$-module, then $A\to B$ is
flat and is a relative complete intersection (i.e. $B/\mathfrak{m}_AB$ is a
complete intersection). Then we explain how this result allows to simplify
Wiles's proof of Fermat's Last Theorem: we do not need the so-called
"Taylor-Wiles systems" anymore.


title:
A Novel Distributed Pseudo TDMA Channel Access Protocol for
  Multi-Transmit-Receive Wireless Mesh Networks

abstract:
  Wireless Mesh Networks (WMNs) technology has been used in recent years for
broadband access in both cities and rural areas. A key development is to equip
routers with multiple directional antennas so that these routers can transmit
to, or receive from multiple neighbors simultaneously. The
Multi-Transmit-Receive (MTR) feature can boost network capacity significantly
if suitable scheduling policy is applied. In this paper, we propose a
distributed link scheduler called PCP-TDMA that fully utilizes the MTR
capability. In particular, it activates every link at least once within the
shortest period of time. We evaluated the performance of PCP-TDMA in various
network topologies, and compared it against a centralized algorithm called
ALGO-2, and two distributed approaches: JazzyMAC and ROMA. The results show
that PCP-TDMA achieves similar performance with the centralized algorithm in
all scenarios, and outperforms the distributed approaches significantly.
Specifically, in a fully connected network, the resulting superframe length of
PCP-TDMA is less than 1/3 and 1/2 of JazzyMAC and ROMA, respectively.


title: MoCap-guided Data Augmentation for 3D Pose Estimation in the Wild

abstract:
  This paper addresses the problem of 3D human pose estimation in the wild. A
significant challenge is the lack of training data, i.e., 2D images of humans
annotated with 3D poses. Such data is necessary to train state-of-the-art CNN
architectures. Here, we propose a solution to generate a large set of
photorealistic synthetic images of humans with 3D pose annotations. We
introduce an image-based synthesis engine that artificially augments a dataset
of real images with 2D human pose annotations using 3D Motion Capture (MoCap)
data. Given a candidate 3D pose our algorithm selects for each joint an image
whose 2D pose locally matches the projected 3D pose. The selected images are
then combined to generate a new synthetic image by stitching local image
patches in a kinematically constrained manner. The resulting images are used to
train an end-to-end CNN for full-body 3D pose estimation. We cluster the
training data into a large number of pose classes and tackle pose estimation as
a K-way classification problem. Such an approach is viable only with large
training sets such as ours. Our method outperforms the state of the art in
terms of 3D pose estimation in controlled environments (Human3.6M) and shows
promising results for in-the-wild images (LSP). This demonstrates that CNNs
trained on artificial images generalize well to real images.


title:
A no-go theorem for the dark matter interpretation of the positron
  anomaly

abstract:
  The overabundance of high-energy cosmic positrons, observed by PAMELA and
AMS-02, can be considered as the consequence of dark matter decays or
annihilations. We show that recent FERMI/LAT measurements of the isotropic
diffuse gamma-ray background impose severe constraints on dark matter
explanations and make them practically inconsistent.


title: Tests of quark-hadron duality in tau-decays

abstract:
  An exhaustive number of QCD finite energy sum rules for $\tau$-decay together
with the latest updated ALEPH data is used to test the assumption of global
duality. Typical checks are the absence of the dimension $d=2$ condensate, the
equality of the gluon condensate extracted from vector or axial vector spectral
functions, the Weinberg sum rules, the chiral condensates of dimensions $d=6$
and $d=8$, as well as the extraction of some low-energy parameters of chiral
perturbation theory. Suitable pinched linear integration kernels are introduced
in the sum rules in order to suppress potential quark-hadron duality violations
and experimental errors. We find no compelling indications of duality
violations in hadronic $\tau$-decay in the kinematic region above $s\simeq2.2$
GeV$^{2}$ for these kernels.


title: First Evaluation of Dynamic Aperture at Injection for FCC-hh

abstract:
  In the Hadron machine option, proposed in the context of the Future Circular
Colliders (FCC) study, the dipole field quality is expected to play an
important role, as in the LHC. A preliminary evaluation of the field quality of
dipoles, based on the Nb$_{3}$Sn technology, has been provided by the magnet
group. The effect of these field imperfections on the dynamic aperture, using
the present lattice design, is presented and first tolerances on the b$_3$ and
b$_5$ multipole components are evaluated.


title:
Scalar versus fermionic top partner interpretations of $t\bar t +
  E_T^{\rm miss}$ searches at the LHC

abstract:
  We assess how different ATLAS and CMS searches for supersymmetry in the
$t\bar t + E_T^{\rm miss}$ final state at Run 1 of the LHC constrain scenarios
with a fermionic top partner and a dark matter candidate. We find that the
efficiencies of these searches in all-hadronic, 1-lepton and 2-lepton channels
are quite similar for scalar and fermionic top partners. Therefore, in general,
efficiency maps for stop-neutralino simplified models can also be applied to
fermionic top-partner models, provided the narrow width approximation holds in
the latter. Owing to the much higher production cross-sections of heavy top
quarks as compared to stops, masses up to $m_T\approx 850$ GeV can be excluded
from the Run 1 stop searches. Since the simplified-model results published by
ATLAS and CMS do not extend to such high masses, we provide our own efficiency
maps obtained with CheckMATE and MadAnalysis 5 for these searches. Finally, we
also discuss how generic gluino/squark searches in multi-jet final states
constrain heavy top partner production.


title:
Deciphering chemical order/disorder and material properties at the
  single-atom level

abstract:
  Correlating 3D arrangements of atoms and defects with material properties and
functionality forms the core of several scientific disciplines. Here, we
determined the 3D coordinates of 6,569 iron and 16,627 platinum atoms in a
model iron-platinum nanoparticle system to correlate 3D atomic arrangements and
chemical order/disorder with material properties at the single-atom level. We
identified rich structural variety and chemical order/disorder including 3D
atomic composition, grain boundaries, anti-phase boundaries, anti-site point
defects and swap defects. We show for the first time that experimentally
measured 3D atomic coordinates and chemical species with 22 pm precision can be
used as direct input for first-principles calculations of material properties
such as atomic magnetic moments and local magnetocrystalline anisotropy. This
work not only opens the door to determining 3D atomic arrangements and chemical
order/disorder of a wide range of nanostructured materials with high precision,
but also will transform our understanding of structure-property relationships
at the most fundamental level.


title:
Fast and robust mesh generation on the sphere Application to coastal
  domains

abstract:
  This paper presents a fast an robust mesh generation procedure that is able
to generate meshes of the earth system (ocean and continent) in matters of
seconds. Our algorithm takes as input a standard shape-file i.e. geospatial
vector data format for geographic information system (GIS) software. The input
is initially coarsened in order to automatically remove unwanted channels that
are under a desired resolution. A valid non-overlapping 1D mesh is then created
on the sphere using the Euclidian coordinates system $x,y,z$. A modified
Delaunay kernel is then proposed that enables to generate meshes on the sphere
in a straightforward manner without parametrization. One of the main difficulty
in dealing with geographical data is the over-sampled nature of coastline
representations. We propose here an algorithm that automatically unrefines
coastline data. Small features are automatically removed while always keeping a
valid (non-overlapping) geometrical representation of the domain. A Delaunay
refinement procedure is subsequently applied to the domain. The refinement
scheme is also multi-threaded at a fine grain level, allowing to generate about
a million points per second on 8 threads. Examples of meshes of the Baltic sea
as well as of the global ocean are presented.


title:
Peak of spectral energy distribution play an important role in intra-day
  variability of Blazars?

abstract:
  Blazars can be divided into two sub-classes namely high energy and low energy
peaked blazars. In spectral energy distribution, the first synchrotron hump of
the former class peaks in UV/X-rays and in IR/optical bands for the latter
class. The peak of the spectral energy distribution seems to be responsible for
variability properties of these classes of blazars in X-ray and optical bands.
Since, in low energy peaked blazars, the X-ray bands lies well below the
synchrotron hump, one expects that the highest energy electrons available for
the synchrotron emission would have slower effect of variability on X-ray
intra-day timescale. In this paper, by taking the advantage of a sample of 12
low energy peaked blazars with total 50 observations from XMM$-$Newton since
its launch, we confirm that this class is less variable in X-ray bands. We
found that out of 50 observational light curves, genuine intra-day variability
is present in only two of light curves i.e 4%. Similar results we obtained from
our earlier optical intra-day variability studies of high energy peaked blazars
where out of 144 light curves, only genuine intra-day variability was detected
in 6 light curves i.e ~ 4%. Since, X-ray bands lie below the peak of the
spectral energy distribution of LSPs where inverse Compton mechanism is
dominating rather than synchrotron radiation at the peak of the optical band,
leads to slower variability in the X-ray bands. Hence, reducing their intra-day
variability in X-ray bands as compared to the variability in optical bands.


title:
[OIII] emission line as a tracer of star-forming galaxies at high
  redshifts: Comparison between H$\alpha$ and [OIII] emitters at $z$=2.23 in
  HiZELS

abstract:
  We investigate the properties of $z$=2.23 H$\alpha$ and [OIII]$\lambda$5007
emitters using the narrow-band-selected samples obtained from the High-$z$
Emission Line Survey (HiZELS: Sobral et al. 2013). We construct two samples of
the H$\alpha$ and [OIII] emitters and compare their integrated physical
properties. We find that the distribution of stellar masses, dust extinction,
star formation rates (SFRs), and specific SFRs, is not statistically different
between the two samples. When we separate the full galaxy sample into three
subsamples according to the detections of the H$\alpha$ and/or [OIII] emission
lines, most of the sources detected with both H$\alpha$ and [OIII] show ${\rm
log(sSFR_{UV})}$$\gtrsim$-9.5. The comparison of the three subsamples suggests
that sources with strong [OIII] line emission tend to have the highest
star-forming activity out all galaxies that we study. We argue that the [OIII]
emission line can be used as a tracer of star-forming galaxies at high
redshift, and that it is especially useful to investigate star-forming galaxies
at $z$$>$3, for which H$\alpha$ emission is no longer observable from the
ground.


title: Time-domain quantum interference in graphene

abstract:
  The electron momentum density obtained from the Schwinger-like mechanism is
evaluated for a graphene sample immersed in a homogeneous time-dependent
electric field. Based on the analogy between graphene low-energy electrons and
quantum electrodynamics (QED), numerical techniques borrowed from strong field
QED are employed and compared to approximate analytical approaches. It is
demonstrated that for some range of experimentally accessible parameters, the
pair production proceeds by sequences of adiabatic evolutions followed by
non-adiabatic Landau-Zener transitions, reminiscent of the Kibble-Zurek
mechanism describing topological defect density in second order phase
transitions. For some field configurations, this yields interference patterns
in momentum space which are explained in terms of the adiabatic-impulse model
and the Landau-Zener-St\"{u}ckelberg interferometry.


title:
Shear Nulling after PSF Gaussianisation: moment-based weak lensing
  measurements with subpercent noise bias

abstract:
  Current optical imaging surveys for cosmology are covering large areas of
sky. To exploit the statistical power of these surveys for weak lensing
measurements requires shape measurement methods with subpercent systematic
errors. We introduce a new weak lensing shear measurement algorithm, Shear
Nulling after PSF Gaussianisation (SNAPG), designed to avoid the noise biases
that affect most other methods. SNAPG operates on images that have been
convolved with a kernel that renders the Point Spread Function (PSF) a circular
Gaussian, and uses weighted second moments of the sources. The response of such
second moments to a shear of the pre-seeing galaxy image can be predicted
analytically, allowing us to construct a shear nulling scheme that finds the
shear parameters for which the observed galaxies are consistent with an
unsheared, isotropically oriented population of sources. The inverse of this
nulling shear is then an estimate of the gravitational lensing shear. We
identify the uncertainty of the estimated centre of each galaxy as the source
of noise bias, and incorporate an approximate estimate of the centroid
covariance into the scheme. We test the method on extensive suites of simulated
galaxies of increasing complexity, and find that it is capable of shear
measurements with multiplicative bias below 0.5 percent.


title: On the linearized log-KdV equation

abstract:
  The logarithmic KdV (log-KdV) equation admits global solutions in an energy
space and exhibits Gaussian solitary waves. Orbital stability of Gaussian
solitary waves is known to be an open problem. We address properties of
solutions to the linearized log-KdV equation at the Gaussian solitary waves. By
using the decomposition of solutions in the energy space in terms of Hermite
functions, we show that the time evolution is related to a Jacobi difference
operator with a limit circle at infinity. This exact reduction allows us to
characterize both spectral and linear orbital stability of solitary waves. We
also introduce a convolution representation of solutions to the log-KdV
equation with the Gaussian weight and show that the time evolution in such a
weighted space is dissipative with the exponential rate of decay.


title:
On the structure observed in the in-flight ${}^{3}\text{He} ( K^{-} , \,
  \Lambda p ) n$ reaction at J-PARC

abstract:
  A theoretical investigation is done to clarify the origin of the peak
structure observed near the $K^{-} p p$ threshold in the in-flight
${}^{3}\text{He} ( K^{-}, \, \Lambda p ) n$ reaction of the J-PARC E15
experiment, which could be a signal of the lightest kaonic nuclei, that is, the
$\bar{K} N N (I=1/2)$ state. For the investigation, we evaluate the $\Lambda p$
invariant mass spectrum assuming two possible scenarios to interpret the
experimental peak. One assumes that the $\Lambda (1405)$ resonance is generated
after the emission of an energetic neutron from the absorption of the initial
$K^-$, not forming a bound state with the remaining proton. This uncorrelated
$\Lambda (1405) p$ system subsequently decays into the final $\Lambda p$. The
other scenario implies that, after the emission of the energetic neutron, a
$\bar{K} N N$ bound state is formed, decaying eventually into a $\Lambda p$
pair. Our results show that the experimental signal observed in the in-flight
${}^{3}\text{He} ( K^{-} , \, \Lambda p ) n$ reaction at J-PARC is
qualitatively well reproduced by the assumption that a $\bar{K} N N$ bound
state is generated in the reaction, definitely discarding the interpretation in
terms of an uncorrelated $\Lambda (1405) p$ state.


title: HIRAX: A Probe of Dark Energy and Radio Transients

abstract:
  The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a new
400-800MHz radio interferometer under development for deployment in South
Africa. HIRAX will comprise 1024 six meter parabolic dishes on a compact grid
and will map most of the southern sky over the course of four years. HIRAX has
two primary science goals: to constrain Dark Energy and measure structure at
high redshift, and to study radio transients and pulsars. HIRAX will observe
unresolved sources of neutral hydrogen via their redshifted 21-cm emission line
(`hydrogen intensity mapping'). The resulting maps of large-scale structure at
redshifts 0.8-2.5 will be used to measure Baryon Acoustic Oscillations (BAO).
HIRAX will improve upon current BAO measurements from galaxy surveys by
observing a larger cosmological volume (larger in both survey area and redshift
range) and by measuring BAO at higher redshift when the expansion of the
universe transitioned to Dark Energy domination. HIRAX will complement CHIME, a
hydrogen intensity mapping experiment in the Northern Hemisphere, by completing
the sky coverage in the same redshift range. HIRAX's location in the Southern
Hemisphere also allows a variety of cross-correlation measurements with
large-scale structure surveys at many wavelengths. Daily maps of a few thousand
square degrees of the Southern Hemisphere, encompassing much of the Milky Way
galaxy, will also open new opportunities for discovering and monitoring radio
transients. The HIRAX correlator will have the ability to rapidly and
eXperimentciently detect transient events. This new data will shed light on the
poorly understood nature of fast radio bursts (FRBs), enable pulsar monitoring
to enhance long-wavelength gravitational wave searches, and provide a rich data
set for new radio transient phenomena searches. This paper discusses the HIRAX
instrument, science goals, and current status.


title: Detecting Communities under Differential Privacy

abstract:
  Complex networks usually expose community structure with groups of nodes
sharing many links with the other nodes in the same group and relatively few
with the nodes of the rest. This feature captures valuable information about
the organization and even the evolution of the network. Over the last decade, a
great number of algorithms for community detection have been proposed to deal
with the increasingly complex networks. However, the problem of doing this in a
private manner is rarely considered. In this paper, we solve this problem under
differential privacy, a prominent privacy concept for releasing private data.
We analyze the major challenges behind the problem and propose several schemes
to tackle them from two perspectives: input perturbation and algorithm
perturbation. We choose Louvain method as the back-end community detection for
input perturbation schemes and propose the method LouvainDP which runs Louvain
algorithm on a noisy super-graph. For algorithm perturbation, we design
ModDivisive using exponential mechanism with the modularity as the score. We
have thoroughly evaluated our techniques on real graphs of different sizes and
verified their outperformance over the state-of-the-art.


title: Representing Verbs with Rich Contexts: an Evaluation on Verb Similarity

abstract:
  Several studies on sentence processing suggest that the mental lexicon keeps
track of the mutual expectations between words. Current DSMs, however,
represent context words as separate features, thereby loosing important
information for word expectations, such as word interrelations. In this paper,
we present a DSM that addresses this issue by defining verb contexts as joint
syntactic dependencies. We test our representation in a verb similarity task on
two datasets, showing that joint contexts achieve performances comparable to
single dependencies or even better. Moreover, they are able to overcome the
data sparsity problem of joint feature spaces, in spite of the limited size of
our training corpus.


title:
Estimating the Dissemination of Social and Mobile Search in Categories
  of Information Needs Using Websites as Proxies

abstract:
  With the increasing popularity of social means to satisfy information needs
using Social Media (e.g., Social Media Question Asking, SMQA) or Social
Information Retrieval approaches, this paper tries to identify types of
information needs which are inherently social and therefore better suited for
those techniques. We describe an experiment where prominent websites from
various content categories are used to represent their respective content area
and allow to correlate attributes of the content areas. The underlying
assumption is that successful websites for focused content areas perfectly
align with the information seekers' requirements when satisfying information
needs in the respective content areas. Based on a manually collected dataset of
URLs from websites covering a broad range of topics taken from Alexa
(http://www.alexa.com} (retrieved 2015-11-04)) (a company that publishes
statistics about web traffic), a crowdsourcing approach is employed to rate the
information needs that could get solved by the respective URLs according to
several dimensions (incl. sociality and mobility) to investigate possible
correlations with other attributes. Our results suggest that information needs
which do not require a certain formal expertise play an important role in
social information retrieval and that some content areas are better suited for
social information retrieval (e.g., Factual Knowledge & News, Games, Lifestyle)
than others (e.g., Health & Lifestyle).


title: Resonance fluorescence from a telecom-wavelength quantum dot

abstract:
  We report on resonance fluorescence from a single quantum dot emitting at
telecom wavelengths. We perform high-resolution spectroscopy and observe the
Mollow triplet in the Rabi regime--a hallmark of resonance fluorescence. The
measured resonance-fluorescence spectra allow us to rule out pure dephasing as
a significant decoherence mechanism in these quantum dots. Combined with
numerical simulations, the experimental results provide robust characterisation
of charge noise in the environment of the quantum dot. Resonant control of the
quantum dot opens up new possibilities for on-demand generation of
indistinguishable single photons at telecom wavelengths as well as quantum
optics experiments and direct manipulation of solid-state qubits in
telecom-wavelength quantum dots.

categories: cond-mat.mes-hall physics.atom-ph physics.optics quant-ph


title: A note on stable recollements

abstract:
  In this short \'etude, we observe that the full structure of a recollement on
a stable infinity-category can be reconstructed from minimal data: that of a
reflective and coreflective full subcategory. The situation has more symmetry
than one would expect at a glance. We end with a practical lemma on gluing
equivalences along a recollement.


title:
Simulations of the Acceleration of Externally Injected Electrons in a
  Plasma Excited in the Linear Regime

abstract:
  We have investigated numerically the coupling between a 10 \si{MeV} electron
bunch of high charge (\SI{> 100}{pc}) with a laser generated accelerating
plasma wave. Our results show that a high efficiency coupling can be achieved
using a \SI{50}{TW}, \SI{100}{\micro \meter} wide laser beam, yielding
accelerating field above \SI{1}{ GV/m}. We propose an experiment where these
predictions could be tested.


title:
A characterization of product-form exchangeable feature probability
  functions

abstract:
  We characterize the class of exchangeable feature allocations assigning
probability $V_{n,k}\prod_{l=1}^{k}W_{m_{l}}U_{n-m_{l}}$ to a feature
allocation of $n$ individuals, displaying $k$ features with counts
$(m_{1},\ldots,m_{k})$ for these features. Each element of this class is
parametrized by a countable matrix $V$ and two sequences $U$ and $W$ of
non-negative weights. Moreover, a consistency condition is imposed to guarantee
that the distribution for feature allocations of $n-1$ individuals is recovered
from that of $n$ individuals, when the last individual is integrated out. In
Theorem 1.1, we prove that the only members of this class satisfying the
consistency condition are mixtures of the Indian Buffet Process over its mass
parameter $\gamma$ and mixtures of the Beta--Bernoulli model over its
dimensionality parameter $N$. Hence, we provide a characterization of these two
models as the only, up to randomization of the parameters, consistent
exchangeable feature allocations having the required product form.


title: On the American swaption in the linear-rational framework

abstract:
  We study American swaptions in the linear-rational (LR) term structure model
introduced in [5]. The American swaption pricing problem boils down to an
optimal stopping problem that is analytically tractable. It reduces to a
free-boundary problem that we tackle by the local time-space calculus of [7].
We characterize the optimal stopping boundary as the unique solution to a
nonlinear integral equation that can be readily solved numerically. We obtain
the arbitrage-free price of the American swaption and the optimal exercise
strategies in terms of swap rates for both fixed-rate payer and receiver swaps.
Finally, we show that Bermudan swaptions can be efficiently priced as well.


title: Deformation quantization of vertex Poisson algebras

abstract:
  We introduce dg Lie algebras controlling the deformations of vertex algebras
and vertex Poisson algebras, utilizing the notion of operadic dg Lie algebra
and the theory of chiral algebra. In terms of those dg Lie algebras, we
formulate the deformation quantization problem of vertex Poisson algebras to
vertex algebras.


title: Level set method for motion by mean curvature

abstract:
  Modeling of a wide class of physical phenomena, such as crystal growth and
flame propagation, leads to tracking fronts moving with curvature-dependent
speed. When the speed is the curvature this leads to one of the classical
degenerate nonlinear second order differential equations on Euclidean space.
One naturally wonders "what is the regularity of solutions?" A priori solutions
are only defined in a weak sense, but it turns out that they are always twice
differentiable classical solutions. This result is optimal; their second
derivative is continuous only in very rigid situations that have a simple
geometric interpretation. The proof weaves together analysis and geometry.
Without deeply understanding the underlying geometry, it is impossible to prove
fine analytical properties.


title: Tangle Functors from Semicyclic Representations

abstract:
  Let $q$ be a $2N$th root of unity where $N$ is odd. Let $U_q(sl_2)$ denote
the quantum group with large center corresponding to the lie algebra $sl_2$
with generators $E,F,K$, and $K^{-1}$. A semicyclic representation of
$U_q(sl_2)$ is an $N$-dimensional irreducible representation
$\rho:U_q(sl_2)\rightarrow M_N(\mathbb{C})$, so that $\rho(E^N)=aId$ with
$a\neq 0$, $\rho(F^N)=0$ and $\rho(K^N)=Id$. We construct a tangle functor for
framed homogeneous tangles colored with semicyclic representations, and prove
that for $(1,1)$-tangles coming from knots, the invariant defined by the tangle
functor coincides with Kashaev's invariant.


title: On Selfish Creation of Robust Networks

abstract:
  Robustness is one of the key properties of nowadays networks. However,
robustness cannot be simply enforced by design or regulation since many
important networks, most prominently the Internet, are not created and
controlled by a central authority. Instead, Internet-like networks emerge from
strategic decisions of many selfish agents. Interestingly, although lacking a
coordinating authority, such naturally grown networks are surprisingly robust
while at the same time having desirable properties like a small diameter.
  To investigate this phenomenon we present the first simple model for selfish
network creation which explicitly incorporates agents striving for a central
position in the network while at the same time protecting themselves against
random edge-failure. We show that networks in our model are diverse and we
prove the versatility of our model by adapting various properties and
techniques from the non-robust versions which we then use for establishing
bounds on the Price of Anarchy. Moreover, we analyze the computational hardness
of finding best possible strategies and investigate the game dynamics of our
model.


title: Electron Transmission through Modified Benzene

abstract:
  The renormalization method is applied to investigate the electron
transmission properties of a circuit containing a benzene molecule, in which
one of the carbon atoms has been modified so as to simulate displacement in
position or replacement by another atom. Consideration of the different
possible attachments of the leads, and the relative location of the modified
atom, results in 9 distinct configurations to examine. For each configuration,
the number and locations of anti-resonances, and whether they shift upon
variation of the parameters, is seen to be the key to determining the shape of
the electron-transmission curve. In particular, those configurations, in which
the perturbed atom is not directly attached to a lead, are seen to have the
most variation in their structure, compared to pure benzene.


title: MHD turbulence and distributed chaos

abstract:
  It is shown, using results of recent direct numerical simulations, that
spectral properties of distributed chaos in MHD turbulence with zero mean
magnetic field are similar to those of hydrodynamic turbulence. An exception is
MHD spontaneous breaking of space translational symmetry, when the stretched
exponential spectrum $\exp(-k/k_{\beta})^{\beta}$ has $\beta=4/7$.


title:
Origin of the electron disproportionation in the metallic sodium
  cobaltates

abstract:
  Recently the unusual metallic state with a substantially non-uniform
distribution of a charge and mag\-ne\-tic density in CoO$_2$ planes was found
experimentally in the Na$_x$CoO$_2$ compound with $x>0.6$. We have investigated
an origin of such electron disproportionation in the lamellar sodium cobaltates
by calculating the ion states as a function of a strength of the electron
correlations in the $d$(Co)-shells within the GGA+U approximation for the
system with a realistic crystal structure. It was found that the nonuniformity
of spin and charge densities are induced by an ordering of the sodium cations
and enhanced correlations. Two important magnetic states of cobalt lattice
competing with each other at realistic values of the correlation parameter were
found~---~low spin hexagons (LS) and higher spin kagom\'e lattice (HS-KSL). In
the heterogeneous metallic HS-KSL phase magnetic Co ions form a kagom\'e
structure. In LS phase the kagom\'e pattern is decomposed into hexagons and Co
ions possess minimal values of their spin. Coexistence of these states could
explain the emergence of the disproportionation with the peculiar kagom\'e
structure experimentally revealed in previous studies of the cobaltates.


title: Improved radial basis function approach with the odd-even corrections

abstract:
  The radial basis function (RBF) approach has been used to improve the mass
predictions of nuclear models. However, systematic deviations exist between the
improved masses and the experimental data for nuclei with different odd-even
parities of ($Z$, $N$), i.e., the (even $Z$, even $N$), (even $Z$, odd $N$),
(odd $Z$, even $N$), and (odd $Z$, odd $N$). By separately training the RBF for
these four different groups, it is found that the systematic odd-even
deviations can be cured in a large extend and the predictive power of nuclear
mass models can thus be further improved. Moreover, this new approach can
better reproduce the single-nucleon separation energies. Based on the latest
version of Weizs\"acker-Skyrme model WS4, the root-mean-square deviation of the
improved masses with respect to known data falls to $135$ keV, approaching the
chaos-related unpredictability limit ($\sim 100$ keV).


title: The universe remembers no wavefunction collapse

abstract:
  Two thought experiments are analyzed, revealing that the quantum state of the
universe does not contain definitive evidence of the wavefunction collapse. The
first thought experiment shows that unitary quantum evolution alone can account
for the outcomes of any combination of quantum experiments. This is in
contradiction with the standard view on quantum measurement, which appeals to
the wavefunction collapse, but it is in full agreement with the special state
proposal (L.S. Schulman in Phys Lett A 102(9):396-400, 1984; J Stat Phys
42(3):689-719 1986; Time's arrows and quantum measurement, Cambridge University
Press, Cambridge 1997) that there are some rare states that account for quantum
experiments by unitary evolution alone. The second thought experiment consists
in successive measurements, and reveals that the standard quantum measurement
scheme predicts violations of the conservation laws. It is shown that the
standard view on quantum measurements makes some unnecessary assumptions which
lead to the apparent necessity to invoke wavefunction collapse. Once these
assumptions are removed, a new hope of a measurement scheme emerges, which,
while still having open problems, is compatible with both the unitary evolution
and the conservation laws, and suggests means to experimentally distinguish
between full unitarity and discontinuous collapse.


title:
First hitting time of the boundary of a wedge of angle $\pi/4$ by a
  radial Dunkl process

abstract:
  In this paper, we derive an integral representation for the density of the
reciprocal of the first hitting time of the boundary of a wedge of angle
$\pi/4$ by a radial Dunkl process with equal multiplicity values. Not only this
representation readily yields the non negativity of the density, but also
provides an analogue of Dufresne's result on the distribution of the first
hitting time of zero by a Bessel process and a generalization of the
Vakeroudis-Yor's identity satisfied by the first exit time from a wedge by a
planar Brownian motion. We also use a result due to Spitzer on the angular part
of the planar Brownian motion to prove a representation of the tail
distribution of its first exit time from a dihedral wedge through the square
wave function.


title:
DeepChrome: Deep-learning for predicting gene expression from histone
  modifications

abstract:
  Motivation: Histone modifications are among the most important factors that
control gene regulation. Computational methods that predict gene expression
from histone modification signals are highly desirable for understanding their
combinatorial effects in gene regulation. This knowledge can help in developing
'epigenetic drugs' for diseases like cancer. Previous studies for quantifying
the relationship between histone modifications and gene expression levels
either failed to capture combinatorial effects or relied on multiple methods
that separate predictions and combinatorial analysis. This paper develops a
unified discriminative framework using a deep convolutional neural network to
classify gene expression using histone modification data as input. Our system,
called DeepChrome, allows automatic extraction of complex interactions among
important features. To simultaneously visualize the combinatorial interactions
among histone modifications, we propose a novel optimization-based technique
that generates feature pattern maps from the learnt deep model. This provides
an intuitive description of underlying epigenetic mechanisms that regulate
genes. Results: We show that DeepChrome outperforms state-of-the-art models
like Support Vector Machines and Random Forests for gene expression
classification task on 56 different cell-types from REMC database. The output
of our visualization technique not only validates the previous observations but
also allows novel insights about combinatorial interactions among histone
modification marks, some of which have recently been observed by experimental
studies.


title: Normal subgroups of limit groups of prime index

abstract:
  Motivated by their study of pro-p limit groups, D.H. Kochloukova and P.A.
Zalesskii formulated a question concerning the minimum number of generators
d(N) of a normal subgroup N of prime index p in a non-abelian limit group G
(cf. Question*). It is shown that the analogous question for the rational rank
has an affirmative answer (cf. Thm. A). From this result one may conclude that
the original question of D.H. Kochloukova and P.A. Zalesskii has an affirmative
answer if the abelianization G^{\ab} of G is torsion free and d(G)=d(G^{\ab})
(cf. Cor.~B), or if G has the IF-property (cf. Thm. C).


title:
Intrinsic defects and conduction characteristics of $Sc_2O_3$ in
  thermionic cathode systems

abstract:
  Recent experimental observations indicate that bulk $Sc_2O_3$ (~200 nm
thick), an insulator at room temperature and pressure, must act as a good
electronic conductor during thermionic cathode operation, leading to the
observed high emitted current densities and overall superior emission
properties over conventional thermionic emitters which do not contain
$Sc_2O_3$. Here, we employ ab initio methods using both semilocal and hybrid
functionals to calculate the intrinsic defect energetics of Sc and O vacancies
and interstitials and their effects on the electronic properties of $Sc_2O_3$
in an effort to explain the good conduction of $Sc_2O_3$ observed in
experiment. The defect energetics were used in an equilibrium defect model to
calculate the concentrations of defects and their compensating electron and
hole concentrations at equilibrium. Overall, our results indicate that the
conductivity of $Sc_2O_3$ solely due to the presence of intrinsic defects in
the cathode operating environment is unlikely to be high enough to maintain the
magnitude of emitted current densities obtained from experiment, and that
presence of impurities are necessary to raise the conductivity of $Sc_2O_3$ to
a high enough value to explain the current densities observed in experiment.
The necessary minimum impurity concentration to impart sufficient electronic
conduction is very small (approximately $7.5x10^{-3}$ ppm) and is probably
present in all experiments.


title:
Counting Exceptional Points for Rational Numbers Associated to the
  Fibonacci Sequence

abstract:
  If $\alpha$ is a non-zero algebraic number, we let $m(\alpha)$ denote the
Mahler measure of the minimal polynomial of $\alpha$ over $\mathbb Z$.
  A series of articles by Dubickas and Smyth, and later by the author, develop
a modified version of the Mahler measure called the $t$-metric Mahler measure,
denoted $m_t(\alpha)$.
  For fixed $\alpha\in \bar{\mathbb Q}$, the map $t\mapsto m_t(\alpha)$ is
continuous, and moreover, is infinitely differentiable at all but finitely many
points, called {\it exceptional points} for $\alpha$.
  It remains open to determine whether there is a sequence of elements
$\alpha_n\in \bar{\mathbb Q}$ such that the number of exceptional points for
$\alpha_n$ tends to $\infty$ as $n\to \infty$.
  We utilize a connection with the Fibonacci sequence to formulate a conjecture
on the $t$-metric Mahler measures. If the conjecture is true, we prove that it
is best possible and that it implies the the existence of rational numbers with
as many exceptional points as we like. Finally, with some computational
assistance, we resolve various special cases of the conjecture that constitute
improvements to earlier results.


title:
Testing the running coupling $k_{T}$-factorization formula for the
  inclusive gluon production

abstract:
  The inclusive gluon production at midrapidities is described in the Color
Glass Condensate formalism using the $k_T$ - factorization formula, which was
derived at fixed coupling constant considering the scattering of a dilute
system of partons with a dense one. Recent analysis demonstrated that this
approach provides a satisfactory description of the experimental data for the
inclusive hadron production in $pp/pA/AA$ collisions. However, these studies
are based on the fixed coupling $k_T$ - factorization formula, which does not
take into account the running coupling corrections, which are important to set
the scales present in the cross section. In this paper we consider the running
coupling corrected $k_T$ - factorization formula conjectured some years ago and
investigate the impact of the running coupling corrections on the observables.
In particular, the pseudorapidity distributions and charged hadrons
multiplicity are calculated considering $pp$, $dAu/pPb$ and $AuAu/PbPb$
collisions at RHIC and LHC energies. We compare the corrected running coupling
predictions with those obtained using the original $k_T$ - factorization
assuming a fixed coupling or a prescription for the inclusion of the running of
the coupling. Considering the Kharzeev - Levin - Nardi unintegrated gluon
distribution and a simplified model for the nuclear geometry, we demonstrate
that the distinct predictions are similar for the pseudorapidity distributions
in $pp/pA/AA$ collisions and for the charged hadrons multiplicity in $pp/pA$
collisions. On the other hand, the running coupling corrected $k_T$ -
factorization formula predicts a smoother energy dependence for $dN/d\eta$ in
$AA$ collisions.


title:
Quantum stability of non-linear wave type solutions with intrinsic mass
  parameter in QCD

abstract:
  The problem of existence of a stable vacuum field in a pure quantum
chromodynamics (QCD) is revised. Our approach is based on using classical
stationary non-linear wave type solutions with intrinsic mass scale parameter.
Such solutions can be treated as quantum mechanical wave functions describing
massive spinless states in quantum theory. We verify whether non-linear wave
type solutions can form a stable vacuum field background within the framework
of effective action formalism. We demonstrate that there is a special class of
stationary generalized Wu-Yang monopole solutions which are stable against
quantum gluon fluctuations.


title: The contribution of scalars to ${\cal N}=4$ SYM amplitudes

abstract:
  We analyse the contribution of $2n$ scalars to the Operator Product Expansion
series for MHV gluon scattering amplitudes/polygonal Wilson loops in planar
${\cal N}=4$ SYM. Hence, we sum up on $2n$ for large coupling $\lambda$: the
logarithm of the amplitude is proportional to $\sqrt{\lambda}$, thus competing,
unexpectedly, with the famous classical contribution. We give explicit
expressions for the first terms at large $\lambda$ in case of two and four
scalars. For finalising this analysis, we find profitable an explicit
computation of the $2n$-scalar term at any coupling by means of Young tableaux,
paralleling, under certain aspects, the Nekrasov-Okounkov expressions for
$\mathcal N =2$ SYM prepotential.


title: A Classification Framework for Partially Observed Dynamical Systems

abstract:
  We present a general framework for classifying partially observed dynamical
systems based on the idea of learning in the model space. In contrast to the
existing approaches using model point estimates to represent individual data
items, we employ posterior distributions over models, thus taking into account
in a principled manner the uncertainty due to both the generative
(observational and/or dynamic noise) and observation (sampling in time)
processes. We evaluate the framework on two testbeds - a biological pathway
model and a stochastic double-well system. Crucially, we show that the
classifier performance is not impaired when the model class used for inferring
posterior distributions is much more simple than the observation-generating
model class, provided the reduced complexity inferential model class captures
the essential characteristics needed for the given classification task.


title:
Ellipses of minimal eccentricity inscribed in midpoint diagonal
  quadrilaterals

abstract:
  In an earlier paper of the author, we showed that there is a unique ellipse
of minimal eccentricity, $E_I$, inscribed in any convex quadrilateral, $Q$.
Using a different approach in this paper, we prove that there is a unique
ellipse of minimal eccentricity, $E_I$, inscribed in a midpoint diagonal
quadrilateral, $Q$, which is a quadrilateral with the property that the
intersection point of the diagonals of $Q$ coincides with the midpoint of at
least one of the diagonals of $Q$. Our main result is that if $Q$ is a midpoint
diagonal quadrilateral, then the smallest non-negative angle between equal
conjugate diameters of $E_I$ equals the smallest non-negative angle between the
diagonals of $Q$. This was proven in another earlier paper of the author for
parallelograms.


title: Minimising Dirichlet eigenvalues on cuboids of unit measure

abstract:
  We consider the minimisation of Dirichlet eigenvalues $\lambda_k$, $k \in
\N$, of the Laplacian on cuboids of unit measure in $\R^3$. We prove that any
sequence of optimal cuboids in $\R^3$ converges to a cube of unit measure in
the sense of Hausdorff as $k \rightarrow \infty$.


title:
Constraints on the Distance Moduli, Helium and Metal Abundances, and
  Ages of Globular Clusters from their RR Lyrae and Non-Variable
  Horizontal-Branch Stars. I. M3, M15, and M92

abstract:
  Up-to-date isochrones, zero-age horizontal branch (ZAHB) loci, and
evolutionary tracks for core He-burning stars are applied to the
color-magnitude diagrams (CMDs) of M3, M15, and M92, focusing in particular on
their RR Lyrae populations. Periods for ab- and c-type variables are calculated
using the latest theoretical calibrations of log P_ab and log P_c as a function
of luminosity, mass, effective temperature, and metallicity. Our models are
generally able to reproduce the measured periods to well within the
uncertainties implied by the stellar properties on which pulsation periods
depend, as well as the mean periods and cluster-to-cluster differences in
<P_ab> and <P_c>, on the assumption of well-supported values of E(B-V),
(m-M)_V, and [Fe/H]. While many of the RR Lyrae in M3 lie close to the same
ZAHB that fits the faintest HB stars at bluer or redder colors, the M92
variables are all significantly evolved stars from ZAHB locations on the blue
side of the instability strip. M15 appears to contain a similar population of
HB stars as M92, along with additional helium-enhanced populations not present
in the latter which comprise most of its RR Lyrae stars. The large number of
variables in M15 and the similarity of the observed values of <P_ab> and <P_c>
in M15 and M92 can be explained by HB models that allow for variations in Y.
Similar ages (~12.5 Gyr) are found for all three clusters, making them
significantly younger than the field halo subgiant HD 140283. Our analysis
suggests a preference for stellar models that take diffusive processes into
account.


title:
Belle II studies of missing energy decays and searches for dark photon
  production

abstract:
  The Belle II experiment at the SuperKEKB collider is a major upgrade of the
KEK "$B$ factory" facility in Tsukuba, Japan. The machine is designed for an
instantaneous luminosity of $8\times 10^{35}$~cm$^{-2}$\,s$^{-1}$, and the
experiment is expected to accumulate a data sample of about 50 ab$^{-1}$ well
within the next decade. With this amount of data, decays sensitive to physics
beyond the Standard Model can be studied with unprecedented precision. One
promising set of modes are physics processes with missing energy such as
$B^+\to\tau^+\nu_{\tau}$, $B\to D^{(*)}\tau\nu_{\tau}$, and $B\to
K^{(*)}\nu\bar\nu$ decays. The Belle II data also allows searches for
candidates for the dark photon, the gauge mediator of a hypothetical dark
sector, which has received much attention in the context of dark matter models.


title:
Electron Emission Energy Barriers and Stability of $Sc_2O_3$ with
  Adsorbed Ba and Ba-O

abstract:
  In this study we employ Density Functional Theory (DFT) methods to
investigate the surface energy barrier for electron emission (surface barrier)
and thermodynamic stability of Ba and Ba-O species adsorption under conditions
of high temperature (approximately 1200 K) and low pressure (approximately
$10^{-10}$ Torr) on the low index surfaces of bixbyite $Sc_2O_3$. The role of
Ba in lowering the cathode surface barrier is investigated via adsorption of
atomic Ba and Ba-O dimers, where the highest simulated dimer coverage
corresponds to a single monolayer film of rocksalt BaO. The change of the
surface barrier of a semiconductor due to adsorption of surface species is
decomposed into two parts: a surface dipole component and doping component. The
lowest surface barrier with atomic Ba on $Sc_2O_3$ was found to be 2.12 eV and
2.04 eV for the (011) and (111) surfaces at 3 and 1 Ba atoms per surface unit
cell (0.250 and 0.083 Ba per surface O), respectively. The lowest surface
barrier for Ba-O on $Sc_2O_3$ was found to be 1.21 eV on (011) for a 7 Ba-O
dimer-per-unit-cell coverage (0.583 dimers per surface O). Generally, we found
that Ba in its atomic form on $Sc_2O_3$ surfaces is not stable relative to bulk
BaO, while Ba-O dimer coverages between 3 to 7 Ba-O dimers per (011) surface
unit cell (0.250 to 0.583 dimers per surface O) produce stable structures
relative to bulk BaO. Ba-O dimer adsorption on $Sc_2O_3$ (111) surfaces was
found to be unstable versus BaO over the full range of coverages studied.
Investigation of combined n-type doping and surface dipole modification showed
that their effects interact to yield a reduction less than the two
contributions would yield separately.


title:
The Northern \omega-Scorpiid meteoroid stream: orbits and emission
  spectra

abstract:
  We analyze the activity of the Northern \omega-Scorpiid meteor shower between
2010 and 2012. For this purpose we have employed an array of low-lux CCD video
cameras and spectrographs deployed at different astronomical observatories in
Spain. As a result of our survey, the atmospheric trajectory and radiant
position of 11 of these meteor events were obtained. The tensile strength and
orbital parameters of the progenitor meteoroids have been also calculated. The
calculated orbital data and the behaviour of these meteoroids in the atmosphere
are compatible with an asteroidal origin of this stream. In addition, we
discuss a unique emission spectrum recorded for one of these meteors. This is,
to our knowledge, the first North {\omega}-Scorpiid spectrum discussed in the
scientific literature, and it has provided information about the chemical
nature of the meteoroid and the progenitor body.


title: A Delayed Yule Process

abstract:
  In now classic work, David Kendall (1966) recognized that the Yule process
and Poisson process could be related by a (random) time change. Furthermore, he
showed that the Yule population size rescaled by its mean has an almost sure
exponentially distributed limit as $t\to \infty$. In this note we introduce a
class of coupled delayed Yule processes parameterized by $0 < \alpha \le 1$
that includes the Poisson process at $\alpha = {1/2}$. Moreover we extend
Kendall's limit theorem to include a larger class of positive martingales
derived from functionals that gauge the population genealogy. A somewhat
surprising connection with the Holley-Liggett smoothing transformation also
emerges in this context. Specifically, the latter is exploited to uniquely
characterize the moment generating functions of distributions of the limit
martingales, generalizing Kendall's mean one exponential limit.


title:
Artificial Neural Network and Time Series Modeling Based Approach to
  Forecasting the Exchange Rate in a Multivariate Framework

abstract:
  Any discussion on exchange rate movements and forecasting should include
explanatory variables from both the current account and the capital account of
the balance of payments. In this paper, we include such factors to forecast the
value of the Indian rupee vis a vis the US Dollar. Further, factors reflecting
political instability and lack of mechanism for enforcement of contracts that
can affect both direct foreign investment and also portfolio investment, have
been incorporated. The explanatory variables chosen are the 3 month Rupee
Dollar futures exchange rate (FX4), NIFTY returns (NIFTYR), Dow Jones
Industrial Average returns (DJIAR), Hang Seng returns (HSR), DAX returns (DR),
crude oil price (COP), CBOE VIX (CV) and India VIX (IV). To forecast the
exchange rate, we have used two different classes of frameworks namely,
Artificial Neural Network (ANN) based models and Time Series Econometric
models. Multilayer Feed Forward Neural Network (MLFFNN) and Nonlinear
Autoregressive models with Exogenous Input (NARX) Neural Network are the
approaches that we have used as ANN models. Generalized Autoregressive
Conditional Heteroskedastic (GARCH) and Exponential Generalized Autoregressive
Conditional Heteroskedastic (EGARCH) techniques are the ones that we have used
as Time Series Econometric methods. Within our framework, our results indicate
that, although the two different approaches are quite efficient in forecasting
the exchange rate, MLFNN and NARX are the most efficient.


title: Magneto-optic effects of the Cosmic Microwave Background

abstract:
  Generation of magneto-optic effects by the interaction of the CMB with cosmic
magnetic fields is studied. Effects which generate polarization such as the
Cotton-Mouton effect, vacuum polarization and photon-pseudoscalar mixing in
external magnetic field are studied. Considering the CMB linearly polarized at
decoupling time, it is shown that photon-pseudoscalar mixing in external
magnetic field, the Cotton-Mouton effect in plasma and the vacuum polarization
in cosmic magnetic field, would generate elliptic polarization of the CMB
depending on the photon frequency and magnetic field strength. Among standard
magneto-optic effects, the Cotton-Mouton effect in plasma turns out to be the
dominant effect in the generation of CMB elliptic polarization in the low
frequency part $\nu_0 \sim 10^8-10^9$ Hz with degree of circular polarization
$P_C(T_0)\simeq 10^{-10}-10^{-6}$ for magnetic field amplitude $B_{e0}\sim
100\, \text{nG}-1$ nG. The vacuum polarization in magnetic field is the
dominant process in the high frequency part $\nu_0\geq 10^{10}$ Hz where the
degree of circular polarization at present is $P_C(T_0)\lesssim 10^{-11}$ in
the best scenario. It is shown that photon-pseudoscalar particle mixing in
cosmic magnetic field generates elliptic polarization of the CMB as well and
even in the case of initially unpolarized CMB. New limits/constraints on the
pseudoscalar parameter space are found. By using current limit on the degree of
circular polarization of the CMB, the upper limit of
$|g_{\phi\gamma}|<4.29\times 10^{-19}(\text{G}/B_{e0})$ GeV$^{-1}$ for
$m_\phi<1.6\times 10^{-14}$ eV in the weak mixing case is found. If
$|g_{\phi\gamma}| < 1.17\times 10^{-24}(\text{G}/B_{e0})$ GeV$^{-1}$, a value
of the order $|g_{\phi\gamma}|\simeq 10^{-26}(\text{G}/B_{e0})$ GeV$^{-1}$ for
$m_\phi\simeq 1.6\times 10^{-14}$ eV in the resonant case, from large scale
temperature anisotropy is obtained.


title: Implications of Lorentz symmetry violation on a 5D supersymmetric model

abstract:
  Field models with $n$ extra spatial dimensions have a larger $SO(1,3+n)$
Lorentz symmetry which is broken down to the standard $SO(1,3)$ four
dimensional one by the compactification process. By considering Lorentz
violating operators in a $5D$ supersymmetric Wess-Zumino mo\-del, which
otherwise conserve the standard four dimensional Poincare invariance, we show
that supersymmetry can be restored upon a simple deformation of the
supersymmetric transformations. However, supersymmetry is not preserved in the
effective $4D$ theory that arises after compactification when the $5D$ Lorentz
violating operators do not preserve $Z_2: y\rightarrow -y$ bulk parity. Our
mechanism unveils a possible connection among Lorentz violation and the
Scherk-Schwarz mechanism. We also show that parity preserving models, on the
other hand, do provide well defined supersymmetric KK models.