title: Digital Technologies In The Early Primary School Classroom

abstract:
  Papert's (1980) work with Turtle Geometry offered an early and provocative
vision of how digital technologies could be used with young learners. Since
then, research on digital technology use has focused on the middle and high
school levels. Given the increasing diversity of digital technologies, and
their varied underlying pedagogical goals and design choices, Clements' (2002)
claim that there is no single effect of the computer on mathematics achievement
is as true now as it was a decade ago. However, many advances have been made in
better articulating the range of design choices that are possible, their
potential effect on the cognitive and affective dimensions on mathematics
learning, and their varying demands on the teacher. The aim of this chapter is
to summarise the research literature on the use of digital technologies in the
teaching and learning of mathematics at the k-2 level. In particular, we focus
on literature that contributes to our understanding of how the use of digital
technologies affects and changes the teaching and learning of mathematics -
that is, how different affordances and design choices impact on the way
teachers and learners interact and express themselves mathematically. By
digital technologies we refer to a range of tools including multi-purpose
computer-based software programs, web-based applets, virtual manipulatives,
programming languages, CD-ROMs, games, calculators, touchscreen applications
and interactive whiteboards. The distinction between these various types is not
always evident and, indeed, one goal of this chapter is to provide useful
distinguishing features of these various technologies in order to help
educators better evaluate and choose amongst them.


title: Long-range contributions to double beta decay revisited

abstract:
  We discuss the systematic decomposition of all dimension-7 (d=7) lepton
number violating operators. These d=7 operators produce momentum enhanced
contributions to the long-range part of the neutrinoless double beta decay
amplitude and thus are severely constrained by existing half-live limits. In
our list of possible models one can find contributions to the long-range
amplitude discussed previously in the literature, such as the left-right
symmetric model or scalar leptoquarks, as well as some new models not
considered before. The d=7 operators generate Majorana neutrino mass terms
either at tree-level, 1-loop or 2-loop level. We systematically compare
constraints derived from the mass mechanism to those derived from the
long-range double beta decay amplitude and classify our list of models
accordingly. We also study one particular example decomposition, which produces
neutrino masses at 2-loop level, can fit oscillation data and yields a large
contribution to the long-range double beta decay amplitude, in some detail.


title: An index of summability for pairs of Banach spaces

abstract:
  We introduce the notion of index of summability for pairs of Banach spaces;
for Banach spaces E; F, this index plays the role of a kind of measure of how
the m-homogeneous polynomials from E to F are far from being absolutely
summing. In some cases the optimal index of summability is computed.


title: Relations on words

abstract:
  In the first part of this survey, we present classical notions arising in
combinatorics on words: growth function of a language, complexity function of
an infinite word, pattern avoidance, periodicity and uniform recurrence. Our
presentation tries to set up a unified framework with respect to a given binary
relation.
  In the second part, we mainly focus on abelian equivalence, $k$-abelian
equivalence, combinatorial coefficients and associated relations, Parikh
matrices and $M$-equivalence. In particular, some new refinements of abelian
equivalence are introduced.


title:
Buone pratiche didattiche per prevenire falsi positivi nelle diagnosi di
  discalculia: il progetto PerContare

abstract:
  To contrast the phenomenon of false positives in the diagnoses of dyscalculia
in Italy, among 3rd grade children, a 3-year project (2011-2014), built upon a
collaboration between psychologists and mathematics educators, was carried out.
Within the project specific teaching strategies for preventing and addressing
learning difficulties in arithmetic arising at the beginning of primary school
were designed and tested in schools nation wide. This paper presents the
project's background and the theoretical foundations of the didactical material
designed, providing also some examples. In particular, prototypical examples
will show how the activities, grounded within a kinesthetic-tactile and
visual-spatial approach, are designed to lead to students' interiorization of
part-whole relations, and to their thinking about multiplication through
structured diagrams. Qualitative data confirming effectiveness of the proposed
didactical strategies will also be discussed.


title:
Hermite polynomials, linear flows on the torus, and an uncertainty
  principle for roots

abstract:
  We study a recent result of Bourgain, Clozel and Kahane, a version of which
states that a sufficiently nice function $f:\mathbb{R} \rightarrow \mathbb{R}$
that coincides with its Fourier transform and vanishes at the origin has a root
in the interval $(c, \infty)$, where the optimal $c$ satisfies $0.41 \leq c
\leq 0.64$. A similar result holds in higher dimensions. We improve the
one-dimensional result to $0.45 \leq c \leq 0.594$, and the lower bound in
higher dimensions. We also prove that extremizers exist, and have infinitely
many double roots. With this purpose in mind, we establish a new structure
statement about Hermite polynomials which relates their pointwise evaluation to
linear flows on the torus, and applies to other families of orthogonal
polynomials as well.


title: Characterizing weak solutions for vector optimization problems

abstract:
  This paper provides characterizations of the weak solutions of optimization
problems where a given vector function $F,$ from a decision space $X$ to an
objective space $Y$, is "minimized" on the set of elements $x\in C$ (where
$C\subset X$ is a given nonempty constraint set), satisfying $G\left( x\right)
\leqq_{S}0_{Z},$ where $G$ is another given vector function from $X $ to a
constraint space $Z$ with positive cone $S$. The three spaces $X,Y,$ and $Z$
are locally convex Hausdorff topological vector spaces, with $Y$ and $Z$
partially ordered by two convex cones $K$ and $S,$ respectively, and enlarged
with a greatest and a smallest element. In order to get suitable versions of
the Farkas lemma allowing to obtain optimality conditions expressed in terms of
the data, the triplet $\left( F,G,C\right) ,$ we use non-asymptotic
representations of the $K-$epigraph of the conjugate function of $F+I_{A},$
where $I_{A}$ denotes the indicator function of the feasible set $A,$ that is,
the function associating the zero vector of $Y$ to any element of $A$ and the
greatest element of $Y$ to any element of $X\diagdown A.$


title: Fast model selection by limiting SVM training times

abstract:
  Kernelized Support Vector Machines (SVMs) are among the best performing
supervised learning methods. But for optimal predictive performance,
time-consuming parameter tuning is crucial, which impedes application. To
tackle this problem, the classic model selection procedure based on grid-search
and cross-validation was refined, e.g. by data subsampling and direct search
heuristics. Here we focus on a different aspect, the stopping criterion for SVM
training. We show that by limiting the training time given to the SVM solver
during parameter tuning we can reduce model selection times by an order of
magnitude.


title: On the origin of facular brightness

abstract:
  This paper studies the dependence of the CaIIH line core brightness on the
strength and inclination of photospheric magnetic field, and on the parameters
of convective and wave motions in a facular region at the solar disc center. We
use three simultaneous datasets obtained at the German Vacuum Tower Telescope
(Observatorio del Teide, Tenerife): (1) spectra of BaII 4554 A line registered
with the instrument TESOS to measure the variations of intensity and velocity
through the photosphere up to the temperature minimum; (2) spectropolarimetric
data in FeI 1.56 $\mu$m lines (registered with the instrument TIP II) to
measure photospheric magnetic fields; (3) filtergrams in CaIIH that give
information about brightness fluctuations in the chromosphere. The results show
that the CaIIH brightness in the facula strongly depends on the power of waves
with periods in the 5-min range, that propagate upwards, and also on the phase
shift between velocity oscillations at the bottom photosphere and around the
temperature minimum height, measured from BaII line. The CaIIH brightness is
maximum at locations where the phase shift between temperature and velocity
oscillations lies within 0-100 degrees. There is an indirect influence of
convective motions on the CaIIH brightness. Namely, the higher is the amplitude
of convective velocities and the larger is the height where they change their
direction of motion, the brighter is the facula. Altogether, our results lead
to conclusions that facular regions appear bright not only because of the
Wilson depression in magnetic structures, but also due to real heating.


title:
Distribution of spectral linear statistics on random matrices beyond the
  large deviation function -- Wigner time delay in multichannel disordered
  wires

abstract:
  An invariant ensemble of $N\times N$ random matrices can be characterised by
a joint distribution for eigenvalues $P(\lambda_1,\cdots,\lambda_N)$. The study
of the distribution of linear statistics, i.e. of quantities of the form
$L=(1/N)\sum_if(\lambda_i)$ where $f(x)$ is a given function, appears in many
physical problems. In the $N\to\infty$ limit, $L$ scales as $L\sim N^\eta$,
where the scaling exponent $\eta$ depends on the ensemble and the function $f$.
Its distribution can be written under the form $P_N(s=N^{-\eta}\,L)\simeq
A_{\beta,N}(s)\,\exp\big\{-(\beta N^2/2)\,\Phi(s)\big\}$, where
$\beta\in\{1,\,2,\,4\}$ is the Dyson index. The Coulomb gas technique naturally
provides the large deviation function $\Phi(s)$, which can be efficiently
obtained thanks to a "thermodynamic identity" introduced earlier. We conjecture
the pre-exponential function $A_{\beta,N}(s)$. We check our conjecture on
several well controlled cases within the Laguerre and the Jacobi ensembles.
Then we apply our main result to a situation where the large deviation function
has no minimum (and $L$ has infinite moments)~: this arises in the statistical
analysis of the Wigner time delay for semi-infinite multichannel disordered
wires (Laguerre ensemble). The statistical analysis of the Wigner time delay
then crucially depends on the pre-exponential function $A_{\beta,N}(s)$, which
ensures the decay of the distribution for large argument.

categories: cond-mat.stat-mech cond-mat.mes-hall math-ph math.MP


title:
A Schwarz-type lemma for noncompact manifolds with boundary and
  geometric applications

abstract:
  We prove a Schwarz-type lemma for noncompact manifolds with possibly
noncompact boundary. The result is a consequence of a suitable form of the weak
maximum principle of independent interest. The paper is enriched with
applications to conformal deformations of noncompact manifolds with boundary,
among them a generalization of a classical result by Escobar.


title: Scanning gate imaging in confined geometries

abstract:
  This article reports on tunable electron backscattering investigated with the
biased tip of a scanning force microscope. Using a channel defined by a pair of
Schottky gates, the branched electron flow of ballistic electrons injected from
a quantum point contact is guided by potentials of a tunable height well below
the Fermi energy. The transition from injection into an open two-dimensional
electron gas to a strongly confined channel exhibits three experimentally
distinct regimes: one in which branches spread unrestrictedly, one in which
branches are confined but the background conductance is affected very little,
and one where the branches have disappeared and the conductance is strongly
modified. Classical trajectory-based simulations explain these regimes at the
microscopic level. These experiments allow us to understand under which
conditions branches observed in scanning gate experiments do or do not reflect
the flow of electrons.


title:
Heating of the partially ionized solar chromosphere by waves in magnetic
  structures

abstract:
  In this paper, we show a "proof of concept" of the heating mechanism of the
solar chromosphere due to wave dissipation caused by the effects of partial
ionization. Numerical modeling of non-linear wave propagation in a magnetic
flux tube, embedded in the solar atmosphere, is performed by solving a system
of single-fluid quasi-MHD equations, which take into account the ambipolar term
from the generalized Ohm's law. It is shown that perturbations caused by
magnetic waves can be effectively dissipated due to ambipolar diffusion. The
energy input by this mechanism is continuous and shown to be more efficient
than dissipation of static currents, ultimately leading to chromospheric
temperature increase in magnetic structures.


title: Wrong way maps in uniformly finite homology and homology of groups

abstract:
  Given a non-compact Riemannian manifold M and a submanifold N of codimension
q, we will construct under certain assumptions on both M and N a wrong way map
in uniformly finite homology.
  Using an equivariant version of the construction and applying it to universal
covers, we will construct wrong way maps in homology of groups.
  As applications we discuss obstructions against positive scalar curvature
metrics and against inessentialness.


title:
Two new integrable cases of two-dimensional quantum mechanics with a
  magnetic field

abstract:
  Two integrable cases of two-dimensional Schr\"odinger equation with a
magnetic field are proposed. Using the polar coordinates and the symmetrical
gauge, we will obtain solutions of these equation through Biconfluent and
Confluent Heun functions. The quantization rules will be derived for both
systems under consideration.


title: Causality in 3D Massive Gravity Theories

abstract:
  We study the constraints coming from local causality requirement in various
$2+1$ dimensional dynamical theories of gravity. In topologically massive
gravity, with a single parity non-invariant massive degree of freedom, and in
new massive gravity, with two massive spin-$2$ degrees of freedom, causality
and unitarity are compatible with each other and both require the Newton's
constant to be negative. In their extensions, such as the Born-Infeld gravity
and the minimal massive gravity the situation is similar and quite different
from their higher dimensional counterparts, such as quadratic (e.g.,
Einstein-Gauss-Bonnet) or cubic theories, where causality and unitarity are in
conflict. We study the problem both in asymptotically flat and asymptotically
anti-de Sitter spaces.


title:
Multi-particle correlations in transverse momenta from statistical
  clusters

abstract:
  We evaluate $n$-particle ($n=2,3,4,5$) transverse momentum correlations for
pions and kaons following from the decay of statistical clusters. These
correlation functions could provide strong constraints on a possible existence
of thermal clusters in the process of particle production.


title:
Optimal wavy surface to suppress vortex shedding using second-order
  sensitivity to shape changes

abstract:
  A method to find optimal 2nd-order perturbations is presented, and applied to
find the optimal spanwise-wavy surface for suppression of cylinder wake
instability. Second-order perturbations are required to capture the stabilizing
effect of spanwise waviness, which is ignored by standard adjoint-based
sensitivity analyses. Here, previous methods are extended so that (i) 2nd-order
sensitivity is formulated for base flow changes satisfying linearised
Navier-Stokes, and (ii) the resulting method is applicable to a 2D global
instability problem. This makes it possible to formulate 2nd-order sensitivity
to shape modifications. Using this formulation, we find the optimal shape to
suppress the a cylinder wake instability. The optimal shape is then perturbed
by random distributions in full 3D stability analysis to confirm that it is a
local optimal at the given amplitude and wavelength. Furthermore, it is shown
that none of the 10 random wavy shapes alone stabilize the wake flow at Re=50,
while the optimal shape does. At Re=100, surface waviness of maximum height 1%
of the cylinder diameter is sufficient to stabilize the flow. The optimal
surface creates streaks by passively extracting energy from the base flow
derivatives and effectively altering the tangential velocity component at the
wall, as opposed to spanwise-wavy suction which inputs energy to the normal
velocity component at the wall. This paper presents a fully two-dimensional and
computationally affordable method to find optimal 2nd-order perturbations of
generic flow instability problems and any boundary control (such as boundary
forcing, shape modulation or suction).


title:
Comparison of feature extraction and dimensionality reduction methods
  for single channel extracellular spike sorting

abstract:
  Spikes in the membrane electrical potentials of neurons play a major role in
the functioning of nervous systems of animals. Obtaining the spikes from
different neurons has been a challenging problem for decades. Several schemes
have been proposed for spike sorting to isolate the spikes of individual
neurons from electrical recordings in extracellular media. However, there is
much scope for improvement in the accuracies obtained using the prevailing
methods of spike sorting. To determine more effective spike sorting strategies
using well known methods, we compared different types of signal features and
techniques for dimensionality reduction in feature space. We tried to determine
an optimum or near optimum feature extraction and dimensionality reduction
methods and an optimum or near optimum number of features for spike sorting. We
assessed relative performance of well known methods on simulated recordings
specially designed for development and benchmarking of spike sorting schemes,
with varying number of spike classes and the well established method of
$k$-means clustering of selected features. We found that almost all well known
methods performed quite well. Nevertheless, from spike waveforms of 64 samples,
sampled at 24 kHz, using principal component analysis (PCA) to select around 46
to 55 features led to the better spike sorting performance than most other
methods (Wilcoxon signed rank sum test, $p < 0.001$).


title: Chiral nucleon-nucleon forces in nuclear structure calculations

abstract:
  Realistic nuclear potentials, derived within chiral perturbation theory, are
a major breakthrough in modern nuclear structure theory, since they provide a
direct link between nuclear physics and its underlying theory, namely the QCD.
As a matter of fact, chiral potentials are tailored on the low-energy regime of
nuclear structure physics, and chiral perturbation theory provides on the same
footing two-nucleon forces as well as many-body ones. This feature fits well
with modern advances in ab-initio methods and realistic shell-model. Here, we
will review recent nuclear structure calculations, based on realistic chiral
potentials, for both finite nuclei and infinite nuclear matter.


title: Raman phonon spectrum of the Dzyaloshinskii-Moriya helimagnet Ba2CuGe2O7

abstract:
  The Raman spectrum of Ba2CuGe2O7, a tetragonal insulator which develops
Dzyaloshinsky- Moriya helical magnetism below TN = 3.2 K, has been detected at
temperatures varying from 300 to 80 K in a single crystal, with the radiation
polarized either in the ab plane or along the c axis of its tetragonal cell. 29
phonon lines out of the 35 allowed by the Raman selection rules for the present
geometry were observed, and their vibrational frequencies were found in overall
good agreement with those provided by shell-model calculations. Together with
the previous report on the infrared-active phonons [A. Nucara et al., Phys.
Rev. B 90, 014304 (2014)] the present study provides an exhaustive description,
both experimental and theoretical, of the lattice dynamics in Ba2CuGe2O7.


title: Integration of algebroidal functions

abstract:
  In this paper, we introduce the integration of algebroidal functions on
Riemann surfaces for the first time. Some properties of integration are
obtained. By giving the definition of residues and integral function element,
we obtain the condition that the integral is independent of path. At last, we
prove that the integral of an irreducible algebroidal function is also an
irreducible algebroidal function if all the residues at critical points are
zeros.


title:
Bounds for the response of viscoelastic composites under antiplane
  loadings in the time domain

abstract:
  To derive bounds on the strain and stress response of a two-component
composite material with viscoelastic phases, we revisit the so-called analytic
method (Bergman 1978), which allows one to approximate the complex effective
tensor, function of the ratio of the component shear moduli, as the sum of
poles weighted by positive semidefinite residue matrices. The novelty of this
investigation lies in the application of such a method, previously applied
(Milton 1980; Bergman 1980) to problems involving cyclic loadings in the
frequency domain, to derive bounds in the time domain for the antiplane
viscoelasticity case. The position of the poles and the residues matrices are
the variational parameters of the problem: the aim is to determine such
parameters in order to have the minimum (or maximum) response at any given
moment in time. All the information about the composite is translated for each
fixed pole configuration into constraints on the residues, the so-called sum
rules. The linearity of the constraints, along with the observation that the
response at a fixed time is linear in the residues, enables one to use the
theory of linear programming to reduce the problem to one involving relatively
few non-zero residues. Finally, bounds on the response are obtained by
numerically optimizing over the pole positions. In the examples studied, the
results turn out to be very accurate estimates: if sufficient information about
the composite is available, the bounds can be quite tight over the entire range
of time, allowing one to predict the transient behavior of the composite.
Furthermore, the bounds incorporating the volume fractions (and possibly
transverse isotropy) can be extremely tight at certain specific times.


title: An asymptotic Robin inequality

abstract:
  The conjectured Robin inequality for an integer $n>7!$ is $\sigma(n)<e^\gamma
n \log \log n,$ where $\gamma$ denotes Euler constant, and $\sigma(n)=\sum_{d |
n} d $. Robin proved that this conjecture is equivalent to Riemann hypothesis
(RH). Writing $D(n)=e^\gamma n \log \log n-\sigma(n),$ and
$d(n)=\frac{D(n)}{n},$ we prove unconditionally that $\liminf_{n \rightarrow
\infty} d(n)=0.$ The main ingredients of the proof are an estimate for
Chebyshev summatory function, and an effective version of Mertens third theorem
due to Rosser and Schoenfeld. A new criterion for RH depending solely on
$\liminf_{n \rightarrow \infty}D(n)$ is derived.


title:
CLASH-VLT: Testing the Nature of Gravity with Galaxy Cluster Mass
  Profiles

abstract:
  We use high-precision kinematic and lensing measurements of the total mass
profile of the dynamically relaxed galaxy cluster MACS J1206.2-0847 at $z=0.44$
to estimate the value of the ratio $\eta=\Psi/\Phi$ between the two scalar
potentials in the linear perturbed Friedmann-Lemaitre-Robertson-Walker
metric.[...] Complementary kinematic and lensing mass profiles were derived
from exhaustive analyses using the data from the Cluster Lensing And Supernova
survey with Hubble (CLASH) and the spectroscopic follow-up with the Very Large
Telescope (CLASH-VLT). Whereas the kinematic mass profile tracks only the
time-time part of the perturbed metric (i.e. only $\Phi$), the lensing mass
profile reflects the contribution of both time-time and space-space components
(i.e. the sum $\Phi+\Psi$). We thus express $\eta$ as a function of the mass
profiles and perform our analysis over the radial range $0.5\,Mpc\le r\le
r_{200}=1.96\,Mpc$. Using a spherical Navarro-Frenk-White mass profile, which
well fits the data, we obtain $\eta(r_{200})=1.01\,_{-0.28}^{+0.31}$ at the
68\% C.L. We discuss the effect of assuming different functional forms for mass
profiles and of the orbit anisotropy in the kinematic reconstruction.
Interpreting this result within the well-studied $f(R)$ modified gravity model,
the constraint on $\eta$ translates into an upper bound to the interaction
length (inverse of the scalaron mass) smaller than 2 Mpc. This tight constraint
on the $f(R)$ interaction range is however substantially relaxed when
systematic uncertainties in the analysis are considered. Our analysis
highlights the potential of this method to detect deviations from general
relativity, while calling for the need of further high-quality data on the
total mass distribution of clusters and improved control on systematic effects.


title:
Measuring Blood Glucose Concentrations in Photometric Glucometers
  Requiring Very Small Sample Volumes

abstract:
  Glucometers present an important self-monitoring tool for diabetes patients
and therefore must exhibit high accu- racy as well as good usability features.
Based on an invasive, photometric measurement principle that drastically
reduces the volume of the blood sample needed from the patient, we present a
framework that is capable of dealing with small blood samples, while
maintaining the required accuracy. The framework consists of two major parts:
1) image segmentation; and 2) convergence detection. Step 1) is based on
iterative mode-seeking methods to estimate the intensity value of the region of
interest. We present several variations of these methods and give theoretical
proofs of their convergence. Our approach is able to deal with changes in the
number and position of clusters without any prior knowledge. Furthermore, we
propose a method based on sparse approximation to decrease the computational
load, while maintaining accuracy. Step 2) is achieved by employing temporal
tracking and prediction, herewith decreasing the measurement time, and, thus,
improving usability. Our framework is validated on several real data sets with
different characteristics. We show that we are able to estimate the underlying
glucose concentration from much smaller blood samples than is currently
state-of-the- art with sufficient accuracy according to the most recent ISO
standards and reduce measurement time significantly compared to
state-of-the-art methods.


title:
Note on the Stieltjes constants: series with Stirling numbers of the
  first kind

abstract:
  The Stieltjes constants $\gamma_k(a)$ appear as the coefficients in the
regular part of the Laurent expansion of the Hurwitz zeta function $\zeta(s,a)$
about $s=1$. We generalize the integral and Stirling number series results of
[4] for $\gamma_k(a=1)$. Along the way, we point out another recent asymptotic
development for $\gamma_k(a)$ which provides convenient and accurate results
for even modest values of $k$.


title: Emergent Self-organization in Active Materials

abstract:
  Biological systems exhibit large-scale self-organized dynamics and structures
which enable organisms to perform the functions of life. The field of active
matter strives to develop and understand microscopically-driven nonequilibrium
materials, with emergent properties comparable to those of living systems. This
review will describe two recently developed classes of active matter systems,
in which simple building blocks --- self-propelled colloidal particles or
extensile rod-like particles --- self-organize to form macroscopic structures
with features not possible in equilibrium systems. We summarize the recent
experimental and theoretical progress on each of these systems, and we present
simple descriptions of the physics underlying their emergent behaviors.


title: A common Misconception about the Categorical Arithmetic

abstract:
  Although the categorical arithmetic is not effectively axiomatizable, the
belief that the incompleteness Theorems can be apply to it is fairly common.
Furthermore, the so-called "essential" (or "inherent") semantic incompleteness
of the second-order Logic that can be deduced by these same Theorems does not
imply the standard semantic incompleteness that can be derived using the
Loewenheim-Skolem or the compactness Theorem. This state of affairs has its
origins in an incorrect and misinterpreted Goedel's comment at the Koenigsberg
congress of 1930 and has consolidated due to different circumstances. This
paper aims to clear up these questions and proposes an alternative
interpretation for the Goedel's statement.


title: Epistemological Consequences of the Incompleteness Theorems

abstract:
  After highlighting the cases in which the semantics of a language cannot be
mechanically reproduced (in which case it is called inherent), the main
epistemological consequences of the first incompleteness Theorem for the two
fundamental arithmetical theories are shown: the non-mechanizability for the
truths of the first-order arithmetic and the peculiarities for the model of the
second-order arithmetic. Finally, the common epistemological interpretation of
the second incompleteness Theorem is corrected, proposing the new "Metatheorem
of undemonstrability of internal consistency".


title:
Nanodiamonds carrying quantum emitters with almost lifetime-limited
  linewidths

abstract:
  Nanodiamonds (NDs) hosting optically active defects are an important
technical material for applications in quantum sensing, biological imaging, and
quantum optics. The negatively charged silicon vacancy (SiV) defect is known to
fluoresce in molecular sized NDs (1 to 6 nm) and its spectral properties depend
on the quality of the surrounding host lattice. This defect is therefore a good
probe to investigate the material properties of small NDs. Here we report
unprecedented narrow optical transitions for SiV colour centers hosted in
nanodiamonds produced using a novel high-pressure high-temperature (HPHT)
technique. The SiV zero-phonon lines were measured to have an inhomogeneous
distribution of 1.05 nm at 5 K across a sample of numerous NDs. Individual
spectral lines as narrow as 354 MHz were measured for SiV centres in
nanodiamonds smaller than 200 nm, which is four times narrower than the best
SiV line previously reported for nanodiamonds. Correcting for apparent spectral
diffusion yielded a homogeneous linewith of about 200 MHz, which is close to
the width limit imposed by the radiative lifetime. These results demonstrate
that the direct HPHT synthesis technique is capable of producing nanodiamonds
with high crystal lattice quality, which are therefore a valuable technical
material.

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


title: Nice Neighbors: A brief adventure in mathematical gamification

abstract:
  This is an expository article about the topological theory of digital images,
and a gamification of a research project.


title: Spatial Decay of Rotating Waves in Reaction Diffusion Systems

abstract:
  In this paper we study nonlinear problems for Ornstein-Uhlenbeck operators
\begin{align*}
  A\triangle v(x) + \left\langle Sx,\nabla v(x)\right\rangle + f(v(x)) =
0,\,x\in\mathbb{R}^d,\,d\geqslant 2, \end{align*} where the matrix
$A\in\mathbb{R}^{N,N}$ is diagonalizable and has eigenvalues with positive real
part, the map $f:\mathbb{R}^N\rightarrow\mathbb{R}^N$ is sufficiently smooth
and the matrix $S\in\mathbb{R}^{d,d}$ in the unbounded drift term is
skew-symmetric. Nonlinear problems of this form appear as stationary equations
for rotating waves in time-dependent reaction diffusion systems. We prove under
appropriate conditions that every bounded classical solution $v_{\star}$ of the
nonlinear problem, which falls below a certain threshold at infinity, already
decays exponentially in space, in the sense that $v_{\star}$ belongs to an
exponentially weighted Sobolev space $
W^{1,p}_{\theta}(\mathbb{R}^d,\mathbb{R}^N)$. Several extensions of this basic
result are presented: to complex-valued systems, to exponential decay in higher
order Sobolev spaces and to pointwise estimates. We also prove that every
bounded classical solution $v$ of the eigenvalue problem \begin{align*}
  A\triangle v(x) + \left\langle Sx,\nabla v(x)\right\rangle +
Df(v_{\star}(x))v(x) = \lambda v(x),\,x\in\mathbb{R}^d,\,d\geqslant 2,
\end{align*} decays exponentially in space, provided $\mathrm{Re}\,\lambda$
lies to the right of the essential spectrum. As an application we analyze
spinning soliton solutions which occur in the Ginzburg-Landau equation. Our
results form the basis for investigating nonlinear stability of rotating waves
in higher space dimensions and truncations to bounded domains.


title: Visibility of quantum graph spectrum from the vertices

abstract:
  We investigate the relation between the eigenvalues of the Laplacian with
Kirchhoff vertex conditions on a finite metric graph and a corresponding
Titchmarsh-Weyl function (a parameter-dependent Neumann-to-Dirichlet map). We
give a complete description of all real resonances, including multiplicities,
in terms of the edge lengths and the connectivity of the graph, and apply it to
characterize all eigenvalues which are visible for the Titchmarsh-Weyl
function.


title:
A tractable prescription for large-scale free flight expansion of
  wavefunctions

abstract:
  A numerical recipe is given for obtaining the density image of an initially
compact quantum mechanical wavefunction that has expanded by a large but finite
factor under free flight. The recipe given avoids the memory storage problems
that plague this type of calculation by reducing the problem to the sum of a
number of fast Fourier transforms carried out on the relatively small initial
lattice. The final expanded state is given exactly on a coarser magnified grid
with the same number of points as the initial state. An important application
of this technique is the simulation of measured time-of-flight images in
ultracold atom experiments, especially when the initial clouds contain
superfluid defects. It is shown that such a finite-time expansion, rather than
a far-field approximation is essential to correctly predict images of
defect-laden clouds, even for long flight times. Examples shown are: an
expanding quasicondensate with soliton defects and a matter-wave interferometer
in 3D.


title:
Avoiding the 4-index transformation in one-body reduced density matrix
  functional calculations for separable functionals

abstract:
  One of the major computational bottlenecks in one-body reduced density matrix
(1RDM) functional theory is the evaluation of approximate 1RDM functionals and
their derivatives. The reason is that more advanced approximate functionals are
almost exclusively defined in the natural orbital basis, so a 4-index
transformation of the two-electron integrals appears to be unavoidable. I will
show that this is not the case and that so-called separable functionals can be
evaluated much more efficiently, i.e. only at cubic cost in the basis size.
Since most approximate functionals are actually separable, this new algorithm
is an important development to make 1RDM functional theory calculations
feasible for large electronic systems.

categories: physics.comp-ph cond-mat.other physics.chem-ph quant-ph


title: Counterintuitive strain distribution in axial (In,Ga)N/GaN nanowires

abstract:
  We study the three-dimensional deformation field induced by an axial (In,Ga)N
segment in a GaN nanowire. Using the finite element method within the framework
of linear elasticity theory, we study the dependence of the strain field on the
ratio of segment length and nanowire radius. Contrary to intuition, the
out-of-plane-component of the elastic strain tensor is found to assume large
negative values for a length-to-radius ratio close to one. We show that this
unexpected effect is a direct consequence of the deformation of the nanowire at
the free sidewalls and the associated large shear strain components. Simulated
reciprocal space maps of a single (In,Ga)N/GaN nanowire demonstrate that
nanofocus x-ray diffraction is a suitable technique to assess this peculiar
strain state experimentally.


title:
On the precision of a data-driven estimate of hadronic light-by-light
  scattering in the muon g-2: pseudoscalar-pole contribution

abstract:
  The evaluation of the numerically dominant pseudoscalar-pole contribution to
hadronic light-by-light scattering in the muon g-2 involves the
pseudoscalar-photon transition form factor F_{P gamma^* gamma^*}(-Q_1^2,
-Q_2^2) with P = pi^0, eta, eta^\prime and, in general, two off-shell photons
with spacelike momenta Q_{1,2}^2. We show, in a largely model-independent way,
that for pi^0 (eta, eta^\prime) the region of photon momenta below about 1
(1.5) GeV gives the main contribution to hadronic light-by-light scattering. We
then discuss how the precision of current and future measurements of the
single- and double-virtual transition form factor in different momentum regions
impacts the precision of a data-driven estimate of this contribution to
hadronic light-by-light scattering. Based on Monte Carlo simulations for a
planned first measurement of the double-virtual form factor at BESIII, we find
that for the pi^0, eta, eta^\prime-pole contributions a precision of 14\%,
23\%, 15\% seems feasible. Further improvements can be expected from other
experimental data and also from the use of dispersion relations for the
different form factors themselves.


title: Sums of Products of Riemann Zeta Tails

abstract:
  A recent paper of Furdui and Valean proves some results about sums of
products of "tails" of the series for the Riemann zeta function. We show how
such results can be proved with weaker hypotheses using multiple zeta values,
and also show how they can be generalized to products of three or more such
tails.


title: On the Noise Robustness of Simultaneous Orthogonal Matching Pursuit

abstract:
  In this paper, the joint support recovery of several sparse signals whose
supports present similarities is examined. Each sparse signal is acquired using
the same noisy linear measurement process, which returns fewer observations
than the dimension of the sparse signals. The measurement noise is assumed
additive, Gaussian, and admits different variances for each sparse signal that
is measured. Using the theory of compressed sensing, the performance of
simultaneous orthogonal matching pursuit (SOMP) is analysed for the envisioned
signal model. The cornerstone of this paper is a novel analysis method upper
bounding the probability that SOMP recovers at least one incorrect entry of the
joint support during a prescribed number of iterations. Furthermore, the
probability of SOMP failing is investigated whenever the number of sparse
signals being recovered simultaneously increases and tends to infinity. In
particular, convincing observations and theoretical results suggest that SOMP
committing no mistake in the noiseless case does not guarantee the absence of
error in the noisy case whenever the number of acquired sparse signals scales
to infinity. Finally, simulation results confirm the validity of the
theoretical results.


title:
Transverse-momentum resummation of colorless final states at the
  NNLL+NNLO

abstract:
  We present a general framework that allows to compute the resummed
transverse-momentum distribution of a system of colorless particles. The
implementation is fully differential in the degrees of freedom of the
final-state system. As a first application, we consider the transverse-momentum
spectrum of ZZ and WW boson pairs produced in hadron collisions, where we resum
the logarithmically enhanced contributions due to multiple soft-gluon emission
at small transverse momenta to all orders in perturbation theory. We exploit
the most advanced perturbative information for the ZZ and WW production
processes that is available at present by combining next-to-next-to-leading
order QCD corrections with next-to-next-to-leading logarithmic resummation.


title:
Pricing options on forwards in energy markets: the role of mean
  reversion's speed

abstract:
  Consider the problem of pricing options on forwards in energy markets, when
spot prices follow a geometric multi-factor model in which several rates of
mean reversion appear. In this paper we investigate the role played by slow
mean reversion when pricing and hedging options. In particular, we determine
both upper and lower bounds for the error one makes neglecting low rates of
mean reversion in the spot price dynamics.


title:
State-to-state vibrational kinetics of H$_2$ and H$_2^+$ in a post-shock
  cooling gas with primordial composition

abstract:
  The radiative cooling of shocked gas with primordial chemical composition is
an important process relevant to the formation of the first stars and
structures, as well as taking place also in high velocity cloud collisions and
supernovae explosions. Among the different processes that need to be
considered, the formation kinetics and cooling of molecular hydrogen are of
prime interest, since they provide the only way to lower the gas temperature to
values well below $\sim$10$^4$~K. In previous works, the internal energy level
structure of H$_2$ and its cation has been treated in the approximation of
rovibrational ground state at low densities, or trying to describe the dynamics
using some arbitrary $v>0$ H$_2$ level that is considered representative of the
excited vibrational manifold. In this study, we compute the vibrationally
resolved kinetics for the time-dependent chemical and thermal evolution of the
post-shock gas in a medium of primordial composition. The calculated
non-equilibrium distributions are used to evaluate effects on the cooling
function of the gas and on the cooling time. Finally, we discuss the dependence
of the results to different initial values of the shock velocity and redshift.


abstract:
  Proceedings of the Workshop on High Performance Energy Efficient Embedded
Systems (HIP3ES) 2016. Prague, January 18th. Collocated with HIPEAC 2016
Conference.


title: Gluon TMDs in quarkonium production

abstract:
  I report on our investigations into the impact of (un)polarized transverse
momentum dependent parton distribution functions (TMD PDFs or TMDs) for gluons
at hadron colliders, especially at A Fixed Target Experiment at the LHC
(AFTER@LHC). In the context of high energy proton-proton collisions, we look at
final states with low mass (e.g. $\eta_b$) in order to investigate the
nonperturbative part of TMD PDFs. We study the factorization theorem for the
$q_T$ spectrum of $\eta_b$ produced in proton-proton collisions relying on the
effective field theory approach, defining the tools to perform phenomenological
investigations at next-to-next-to-leading log (NNLL) and next-to-leading order
(NLO) accuracy in the perturbation theory. We provide predictions for the
unpolarized cross section and comment on the possibility of extracting
nonperturbative information about the gluon content of the proton once data at
low transverse momentum are available.


title: A Note on The Multidimensional Moment Problem

abstract:
  In this note, we show that if a multidimensional sequence generates Hankel
tensors and all the Hankel matrices, generated by this sequence, are positive
semi-definite, then this sequence is a multidimensional moment sequence.


title:
Random Distances Associated with Arbitrary Polygons: An Algorithmic
  Approach between Two Random Points

abstract:
  This report presents a new, algorithmic approach to the distributions of the
distance between two points distributed uniformly at random in various
polygons, based on the extended Kinematic Measure (KM) from integral geometry.
We first obtain such random Point Distance Distributions (PDDs) associated with
arbitrary triangles (i.e., triangle-PDDs), including the PDD within a triangle,
and that between two triangles sharing either a common side or a common vertex.
For each case, we provide an algorithmic procedure showing the mathematical
derivation process, based on which either the closed-form expressions or the
algorithmic results can be obtained. The obtained triangle-PDDs can be utilized
for modeling and analyzing the wireless communication networks associated with
triangle geometries, such as sensor networks with triangle-shaped clusters and
triangle-shaped cellular systems with highly directional antennas. Furthermore,
based on the obtained triangle-PDDs, we then show how to obtain the PDDs
associated with arbitrary polygons through the decomposition and recursion
approach, since any polygons can be triangulated, and any geometry shapes can
be approximated by polygons with a needed precision. Finally, we give the PDDs
associated with ring geometries. The results shown in this report can enrich
and expand the theory and application of the probabilistic distance models for
the analysis of wireless communication networks.


title:
New Fractional Derivatives with Nonlocal and Non-Singular Kernel: Theory
  and Application to Heat Transfer Model

abstract:
  In this manuscript we proposed a new fractional derivative with non-local and
no-singular kernel. We presented some useful properties of the new derivative
and applied it to solve the fractional heat transfer model.


title:
Deep Convolutional Neural Networks for Computer-Aided Detection: CNN
  Architectures, Dataset Characteristics and Transfer Learning

abstract:
  Remarkable progress has been made in image recognition, primarily due to the
availability of large-scale annotated datasets and the revival of deep CNN.
CNNs enable learning data-driven, highly representative, layered hierarchical
image features from sufficient training data. However, obtaining datasets as
comprehensively annotated as ImageNet in the medical imaging domain remains a
challenge. There are currently three major techniques that successfully employ
CNNs to medical image classification: training the CNN from scratch, using
off-the-shelf pre-trained CNN features, and conducting unsupervised CNN
pre-training with supervised fine-tuning. Another effective method is transfer
learning, i.e., fine-tuning CNN models pre-trained from natural image dataset
to medical image tasks. In this paper, we exploit three important, but
previously understudied factors of employing deep convolutional neural networks
to computer-aided detection problems. We first explore and evaluate different
CNN architectures. The studied models contain 5 thousand to 160 million
parameters, and vary in numbers of layers. We then evaluate the influence of
dataset scale and spatial image context on performance. Finally, we examine
when and why transfer learning from pre-trained ImageNet (via fine-tuning) can
be useful. We study two specific computer-aided detection (CADe) problems,
namely thoraco-abdominal lymph node (LN) detection and interstitial lung
disease (ILD) classification. We achieve the state-of-the-art performance on
the mediastinal LN detection, with 85% sensitivity at 3 false positive per
patient, and report the first five-fold cross-validation classification results
on predicting axial CT slices with ILD categories. Our extensive empirical
evaluation, CNN model analysis and valuable insights can be extended to the
design of high performance CAD systems for other medical imaging tasks.


title: Derivative self-interactions for a massive vector field

abstract:
  In this work we revisit the construction of theories for a massive vector
field with derivative self-interactions such that only the 3 desired
polarizations corresponding to a Proca field propagate. We start from the
decoupling limit by constructing healthy interactions containing second
derivatives of the Stueckelberg field with itself and also with the transverse
modes. The resulting interactions can then be straightforwardly generalized
beyond the decoupling limit. We then proceed to a systematic construction of
the interactions by using the Levi-Civita tensors. Both approaches lead to a
finite family of allowed derivative self-interactions for the Proca field. This
construction allows us to show that some higher order terms recently introduced
as new interactions trivialize in 4 dimensions by virtue of the Cayley-Hamilton
theorem. Moreover, we discuss how the resulting derivative interactions can be
written in a compact determinantal form, which can also be regarded as a
generalization of the Born-Infeld lagrangian for electromagnetism. Finally, we
generalize our results for a curved background and give the necessary
non-minimal couplings guaranteeing that no additional polarizations propagate
even in the presence of gravity.


title:
Effects of electron temperature anisotropy on proton mirror instability
  evolution

abstract:
  Proton mirror modes are large amplitude nonpropagating structures frequently
observed in the magnetosheath. It has been suggested that electron temperature
anisotropy can enhance the proton mirror instability growth rate while leaving
the proton cyclotron instability largely unaffected, therefore causing the
proton mirror instability to dominate the proton cyclotron instability in
Earth's magnetosheath. Here, we use particle-in-cell simulations to investigate
the electron temperature anisotropy effects on proton mirror instability
evolution. Contrary to the hypothesis, electron temperature anisotropy leads to
excitement of the electron whistler instability. Our results show that the
electron whistler instability grows much faster than the proton mirror
instability and quickly consumes the electron free energy, so that there is no
electron temperature anisotropy left to significantly impact the evolution of
the proton mirror instability.


title: A tripos based on compact Hausdorff spaces

abstract:
  The category of compact Hausdorff spaces is the base of tripos. As such it
can be freely completed to an elementary topos.


title: On rectifying slant helices in Euclidean 3-space

abstract:
  In this paper, we study the position vectors of rectifying slant helices in
$E^3$. First, we have found the general equations of the curvature and the
torsion of rectifying slant helices. After that, we have constructed a second
order linear differential equation and by solving the equation, we have
obtained a family of rectifying slant helices which lie on cones.


title: Charm production in high multiplicity pp events

abstract:
  Recent experimental studies of the multiplicity dependence of heavy quark
(HQ) production in proton-proton collisions at 7 TeV showed a strong non-linear
increase of the HQ multiplicity as a function of the charged particle
multiplicity. We try to understand this behavior using the EPOS3 approach. Two
issues play an important role: multiple scattering, in particular its impact on
multiplicity fluctuations, and the collective hydrodynamic expansion. The
results are very robust with respect to many details of the modeling, which
means that these data contain valuable information about very basic features of
the reaction mechanism in proton-proton collisions.


title: On a recent very simple generalization of DMT theory of adhesion

abstract:
  As the interest in adhesion is shifting towards smaller and smaller scales,
the well known Tabor adhesion parameter decreases and the DMT theory is
frequently considered to be the appropriate limit. A very attractive much
simplified version of DMT has been proposed in a recent investigation of rough
contacts by Pastewka & Robbins (PNAS, 111(9), 3298-3303, 2014) which seems to
work in very general conditions in numerical experiments. However, when
comparing this calculation to the known theories for the sphere, surprisingly
large conflicts occur, and the reason for the success of the numerical
experiments is obscure.


title: Conformal restriction: The trichordal case

abstract:
  The study of conformal restriction properties in two-dimensions has been
initiated by Lawler, Schramm and Werner who focused on the natural and
important chordal case: They characterized and constructed all random subsets
of a given simply connected domain that join two marked boundary points and
that satisfy the additional restriction property. The radial case (sets joining
an inside point to a boundary point) has then been investigated by Wu. In the
present paper, we study the third natural instance of such restriction
properties, namely the "trichordal case", where one looks at random sets that
join three marked boundary points. This case involves somewhat more
technicalities than the other two, as the construction of this family of random
sets relies on special variants of SLE$_{8/3}$ processes with a drift term in
the driving function that involves hypergeometric functions. It turns out that
such a random set can not be a simple curve simultaneously in the neighborhood
of all three marked points, and that the exponent $\alpha = 20/27$ shows up in
the description of the law of the skinniest possible symmetric random set with
this trichordal restriction property.


title:
Spin-orbit torques and spin accumulation in FePt/Pt and Co/Cu thin films
  from first principles: the role of impurities

abstract:
  Using the Boltzmann formalism based on the first principles electronic
structure and scattering rates, we investigate the current-induced spin
accumulation and spin-orbit torques in FePt/Pt and Co/Cu bilayers in the
presence of substitutional impurities. In FePt/Pt bilayers we consider the
effect of intermixing of Fe and Pt atoms in the FePt layer, and find a crucial
dependence of spin accumulation and spin-orbit torques on the details of the
distribution of these defects. In Co/Cu bilayers we predict that the magnitude
and sign of the spin-orbit torque and spin accumulation depend very sensitively
on the type of the impurities used to dope the Cu substrate. Moreover,
simultaneously with impurity-driven scattering we consider the effect of an
additional constant quasiparticle broadening of the states at the Fermi surface
to simulate phonon scattering at room temperature, and discover that even a
small broadening of the order of 25 meV can drastically influence the magnitude
of the considered effects. We explain our findings based on the analysis of the
complex interplay of several competing Fermi surface contributions to the spin
accumulation and spin-orbit torques in these structurally and chemically
non-uniform systems.


title: Triplet Similarity Embedding for Face Verification

abstract:
  In this work, we present an unconstrained face verification algorithm and
evaluate it on the recently released IJB-A dataset that aims to push the
boundaries of face verification methods. The proposed algorithm couples a deep
CNN-based approach with a low-dimensional discriminative embedding learnt using
triplet similarity constraints in a large margin fashion. Aside from yielding
performance improvement, this embedding provides significant advantages in
terms of memory and post-processing operations like hashing and visualization.
Experiments on the IJB-A dataset show that the proposed algorithm outperforms
state of the art methods in verification and identification metrics, while
requiring less training time.


title: Complexity of regular abstractions of one-counter languages

abstract:
  We study the computational and descriptional complexity of the following
transformation: Given a one-counter automaton (OCA) A, construct a
nondeterministic finite automaton (NFA) B that recognizes an abstraction of the
language L(A): its (1) downward closure, (2) upward closure, or (3) Parikh
image.
  For the Parikh image over a fixed alphabet and for the upward and downward
closures, we find polynomial-time algorithms that compute such an NFA. For the
Parikh image with the alphabet as part of the input, we find a quasi-polynomial
time algorithm and prove a completeness result: we construct a sequence of OCA
that admits a polynomial-time algorithm iff there is one for all OCA.
  For all three abstractions, it was previously unknown if appropriate NFA of
sub-exponential size exist.


title: Relative Perturbation Theory for Quadratic Hermitian Eigenvalue Problem

abstract:
  In this paper, we derive new relative perturbation bounds for eigenvectors
and eigenvalues for regular quadratic eigenvalue problems of the form
$\lambda^2 M x + \lambda C x + K x = 0$, where $M$ and $K$ are nonsingular
Hermitian matrices and $C$ is a general Hermitian matrix. We base our findings
on new results for an equivalent regular Hermitian matrix pair $A-\lambda B$.
The new bounds can be applied to many interesting quadratic eigenvalue problems
appearing in applications, such as mechanical models with indefinite damping.
The quality of our bounds is demonstrated by several numerical experiments.


title:
On the dislocation density tensor in the Cosserat theory of elastic
  shells

abstract:
  We consider the Cosserat continuum in its finite strain setting and discuss
the dislocation density tensor as a possible alternative curvature strain
measure in three-dimensional Cosserat models and in Cosserat shell models. We
establish a close relationship (one-to-one correspondence) between the new
shell dislocation density tensor and the bending-curvature tensor of
6-parameter shells.


title:
Herschel observations of the nebula M1-67 around the Wolf-Rayet star WR
  124

abstract:
  Infrared Herschel imaging and spectroscopic observations of the nebula M1-67
around the Wolf-Rayet star WR 124 have been obtained along with optical imaging
observations. The infrared images reveal a clumpy dusty nebula that extends up
to 1 pc. The comparison with the optical images shows that the ionized gas
nebula coincides with the dust nebula, the dust and the gas being mixed
together. A photodissociation region is revealed from the infrared
spectroscopic analysis. The analysis of the infrared spectrum of the nebula,
where forbidden emission lines of ionized elements were detected, showed that
the nebula consists of mildly processed material with the calculated abundance
number ratios being N/O = 1.0 +/- 0.5 and C/O = 0.46 +/- 0.27. Based on a
radiative transfer model, the dust mass of the nebula was estimated to be 0.22
Msun with a population of large grains being necessary to reproduce the
observations. The comparison of the mass-loss rate and the abundance ratios to
theoretical models of stellar evolution led to the conclusion that the nebular
ejection took place during a RSG/YSG evolutionary phase of a central star with
an initial mass of 32 Msun.


title:
Bayesian Evidence Accumulation in Experimental Mathematics: A Case Study
  of Four Irrational Numbers

abstract:
  Many questions in experimental mathematics are fundamentally inductive in
nature. Here we demonstrate how Bayesian inference --the logic of partial
beliefs-- can be used to quantify the evidence that finite data provide in
favor of a general law. As a concrete example we focus on the general law which
posits that certain fundamental constants (i.e., the irrational numbers $\pi$,
$e$, $\sqrt2$, and $\ln{2}$) are normal; specifically, we consider the more
restricted hypothesis that each digit in the constant's decimal expansion
occurs equally often. Our analysis indicates that for each of the four
constants, the evidence in favor of the general law is overwhelming. We argue
that the Bayesian paradigm is particularly apt for applications in experimental
mathematics, a field in which the plausibility of a general law is in need of
constant revision in light of data sets whose size is increasing continually
and indefinitely.


title: The Abelian Sandpile Model on Fractal Graphs

abstract:
  We study the Abelian sandpile model (ASM), a process where grains of sand are
placed on a graph's vertices. When the number of grains on a vertex is at least
its degree, one grain is distributed to each neighboring vertex. This model has
been shown to form fractal patterns on the integer lattice, and using these
fractal patterns as motivation, we consider the model on graph approximations
of post critically finite (p.c.f) fractals. We determine asymptotic behavior of
the diameter of sites toppled and characterize graphs which exhibit a periodic
number of grains with respect to the initial placement.


title: The distance function from the boundary of a domain with corners

abstract:
  We study the regularity of the distance function to the boundary of a domain
in $\mathbb{R}^2$, with respect to some asymmetric norms. We allow the boundary
of the domain to have corners. We obtain an explicit formula for the second
derivative of these distance functions. Furthermore, we study a generalized
notion of the ridge of a domain, which is the set of singularities of a
distance function to the boundary of the domain. We completely characterize the
ridge by using a generalized notion of curvature.


title: Automatic Sarcasm Detection: A Survey

abstract:
  Automatic sarcasm detection is the task of predicting sarcasm in text. This
is a crucial step to sentiment analysis, considering prevalence and challenges
of sarcasm in sentiment-bearing text. Beginning with an approach that used
speech-based features, sarcasm detection has witnessed great interest from the
sentiment analysis community. This paper is the first known compilation of past
work in automatic sarcasm detection. We observe three milestones in the
research so far: semi-supervised pattern extraction to identify implicit
sentiment, use of hashtag-based supervision, and use of context beyond target
text. In this paper, we describe datasets, approaches, trends and issues in
sarcasm detection. We also discuss representative performance values, shared
tasks and pointers to future work, as given in prior works. In terms of
resources that could be useful for understanding state-of-the-art, the survey
presents several useful illustrations - most prominently, a table that
summarizes past papers along different dimensions such as features, annotation
techniques, data forms, etc.


title: Aggregation of supports along the Lasso path

abstract:
  In linear regression with fixed design, we propose two procedures that
aggregate a data-driven collection of supports. The collection is a subset of
the $2^p$ possible supports and both its cardinality and its elements can
depend on the data. The procedures satisfy oracle inequalities with no
assumption on the design matrix. Then we use these procedures to aggregate the
supports that appear on the regularization path of the Lasso in order to
construct an estimator that mimics the best Lasso estimator. If the restricted
eigenvalue condition on the design matrix is satisfied, then this estimator
achieves optimal prediction bounds. Finally, we discuss the computational cost
of these procedures.


title: A 4D gravity theory and G2-holonomy manifolds

abstract:
  Bryant and Salamon gave a construction of metrics of G2 holonomy on the total
space of the bundle of anti-self-dual (ASD) 2-forms over a 4-dimensional
self-dual Einstein manifold. We generalise it by considering the total space of
an SO(3) bundle (with fibers R^3) over a 4-dimensional base, with a connection
on this bundle. We make essentially the same ansatz for the calibrating 3-form,
but use the curvature 2-forms instead of the ASD ones. We show that the
resulting 3-form defines a metric of G2 holonomy if the connection satisfies a
certain second-order PDE. This is exactly the same PDE that arises as the field
equation of a certain 4-dimensional gravity theory formulated as a
diffeomorphism-invariant theory of SO(3) connections. Thus, every solution of
this 4-dimensional gravity theory can be lifted to a G2-holonomy metric. Unlike
all previously known constructions, the theory that we lift to 7 dimensions is
not topological. Thus, our construction should give rise to many new metrics of
G2 holonomy. We describe several examples that are of cohomogeneity one on the
base.


title:
Graphical models for studying museum networks: the Abbonamento Musei
  Torino Piemonte

abstract:
  Probabilistic graphical models are a powerful tool to represent real-word
phenomena and to learn network structures starting from data. This paper
applies graphical models in a new framework to study association rules driven
by consumer choices in a network of museums. The network consists of the
museums participating in the program of Abbonamento Musei Torino Piemonte,
which is a yearly subscription managed by the Associazione Torino Citt\`a
Capitale Europea. Consumers are card-holders, who are allowed to entry to all
the museums in the network for one year. We employ graphical models to
highlight associations among the museums driven by card-holder visiting
behaviour. We use both undirected graphs to investigate the strength of the
network and directed graphs to highlight asimmetry in the association rules.


title:
The extended jet of AP Librae: Origin of the very high-energy gamma-ray
  emission?

abstract:
  The low-frequency peaked BL Lac object (LBL) AP Librae exhibits
very-high-energy (VHE, $E>100$GeV) $\gamma$-ray emission and hosts an extended
jet, which has been detected in radio and X-rays. The jet X-ray spectral index
implies an inverse Compton origin. These observations are unusual for LBLs
calling for a consistent explanation of this extraordinary source. The
observationally constrained parameters necessary to describe the core emission
within the standard one-zone model are unable to explain the broad-band
spectrum, even if observationally unconstrained external photon fields are
taken into account. We demonstrate that the addition of the extended jet
emission successfully reproduces the total spectral energy distribution. In
particular, the VHE radiation is produced in the $>100\,$kpc long extended jet
via inverse Compton scattering of cosmic microwave background photons by highly
relativistic electrons. We present several ways to test this theory. The
extended jet is weakly magnetized ($B_0 = 2.5\,\mu$G), while its minimum and
maximum electron Lorentz factors are $\gamma_{min}=60$ and
$\gamma_{max}=5\times 10^6$, respectively. The electron spectral index is
$s=2.6$. These parameters are comparable to parameters of other blazars with
extended X-ray jets dominated by inverse Compton scattering.


title: Two-component generalizations of the Camassa-Holm equation

abstract:
  A classification of integrable two-component systems of non-evolutionary
partial differential equations that are analogous to the Camassa-Holm equation
is carried out via the perturbative symmetry approach. Independently, a
classification of compatible pairs of Hamiltonian operators is carried out,
which leads to bi-Hamiltonian structures for the same systems of equations.
Some exact solutions and Lax pairs are also constructed for the systems
considered.


title:
On Cherenkov Friction and Radiation of a Neutral Polarizable Particle
  Moving Parallel to a Transparent Dielectric Plate

abstract:
  We have obtained general expressions for the intensity of radiation,
decelerating force, the rate of heating and acceleration of a small polarizable
particle under the conditions of Cherenkov friction: at relativistic motion
parallel to the surface of thick transparent dielectric plate. Comparison with
the results of other authors is given.


title:
Inflation and late-time acceleration from a double-well potential with
  cosmological constant

abstract:
  A model of a universe without big bang singularity is presented, which
displaysanearly inflationary period ending just before a phase transition to a
deflationary epoch. The model produces enough heavy particles so as to reheat
the universe at temperatures in the MeV regime. After the reheating, it
smoothly matches the standard $\Lambda$CDM scenario.


title:
Impact of degree truncation on the spread of a contagious process on
  networks

abstract:
  Understanding how person-to-person contagious processes spread through a
population requires accurate information on connections between population
members. However, such connectivity data, when collected via interview, is
often incomplete due to partial recall, respondent fatigue or study design,
e.g., fixed choice designs (FCD) truncate out-degree by limiting the number of
contacts each respondent can report. Past research has shown how FCD truncation
affects network properties, but its implications for predicted speed and size
of spreading processes remain largely unexplored. To study the impact of degree
truncation on spreading processes, we generated collections of synthetic
networks containing specific properties (degree distribution,
degree-assortativity, clustering), and also used empirical social network data
from 75 villages in Karnataka, India. We simulated FCD using various truncation
thresholds and ran a susceptible-infectious-recovered (SIR) process on each
network. We found that spreading processes propagated on truncated networks
resulted in slower and smaller epidemics, with a sudden decrease in prediction
accuracy at a level of truncation that varied by network type. Our results have
implications beyond FCD to truncation due to any limited sampling from a larger
network. We conclude that knowledge of network structure is important for
understanding the accuracy of predictions of process spread on degree truncated
networks.


title: Topological Integer Additive Set-Sequential Graphs

abstract:
  Let $\mathbb{N}_0$ denote the set of all non-negative integers and $X$ be any
non-empty subset of $\mathbb{N}_0$. Denote the power set of $X$ by
$\mathcal{P}(X)$. An integer additive set-labeling (IASL) of a graph $G$ is an
injective set-valued function $f:V(G)\to \mathcal{P}(X)$ such that the induced
function $f^+:E(G) \to \mathcal{P}(X)$ is defined by $f^+ (uv) = f(u)+ f(v)$,
where $f(u)+f(v)$ is the sumset of $f(u)$ and $f(v)$. If the associated
set-valued edge function $f^+$ is also injective, then such an IASL is called
an integer additive set-indexer (IASI). An IASL $f$ is said to be a topological
IASL (TIASL) if $f(V(G))\cup \{\emptyset\}$ is a topology of the ground set
$X$. An IASL is said to be an integer additive set-sequential labeling (IASSL)
if $f(V(G))\cup f^+(E(G))= \mathcal{P}(X)-\{\emptyset\}$. An IASL of a given
graph $G$ is said to be a topological integer additive set-sequential labeling
of $G$, if it is a topological integer additive set-labeling as well as an
integer additive set-sequential labeling of $G$. In this paper, we study the
conditions required for a graph $G$ to admit this type of IASL and propose some
important characteristics of the graphs which admit this type of IASLs.


title:
High-Dimensional Estimation of Structured Signals from Non-Linear
  Observations with General Convex Loss Functions

abstract:
  In this paper, we study the issue of estimating a structured signal $x_0 \in
\mathbb{R}^n$ from non-linear and noisy Gaussian observations. Supposing that
$x_0$ is contained in a certain convex subset $K \subset \mathbb{R}^n$, we
prove that accurate recovery is already feasible if the number of observations
exceeds the effective dimension of $K$, which is a common measure for the
complexity of signal classes. It will turn out that the possibly unknown
non-linearity of our model affects the error rate only by a multiplicative
constant. This achievement is based on recent works by Plan and Vershynin, who
have suggested to treat the non-linearity rather as noise which perturbs a
linear measurement process. Using the concept of restricted strong convexity,
we show that their results for the generalized Lasso can be extended to a
fairly large class of convex loss functions. Moreover, we shall allow for the
presence of adversarial noise so that even deterministic model inaccuracies can
be coped with. These generalizations particularly give further evidence of why
many standard estimators perform surprisingly well in practice, although they
do not rely on any knowledge of the underlying output rule. To this end, our
results provide a unified and general framework for signal reconstruction in
high dimensions, covering various challenges from the fields of compressed
sensing, signal processing, and statistical learning.


title:
Transport Coefficient to Trace Anomaly in the Clustering of Color
  Sources Approach

abstract:
  From our previously obtained shear viscosity to entropy density ratio
($\eta/s$) in the framework of clustering of color sources (Color String
Percolation Model: CSPM), we calculate the jet quenching parameter $\hat {q}$
and trace anomaly $\Delta = (\varepsilon -3\it p)/T^{4}$ as a function of
temperature. It is shown that the scaled $\hat {q}/T^{3}$ is in agreement with
the recent JET Collaboration estimates. The inverse of $\eta/s$ is found to
represent $\Delta$. The results for $\Delta$ are in excellent agreement with
Lattice Quantum Chromo Dynamics (LQCD) simulations. From the trace anomaly and
energy density $\epsilon$, the equation of state is obtained as a function of
temperature and compared with LQCD simulations. It is possible that there is a
direct connection between the $\eta/s$ and $\Delta$. Thus the estimate of
transport coefficient $\eta/s$ provides $\hat {q}$ and $\Delta$ as a function
of temperature. Both $\Delta$ and $\eta/s$ describe the transition from a
strongly coupled QGP to a weakly coupled QGP.


title: Minkowski valuations under volume constraints

abstract:
  We provide a description of the space of continuous and translation invariant
Minkowski valuations $\Phi:\mathcal{K}^n\to\mathcal{K}^n$ for which there is an
upper and a lower bound for the volume of $\Phi(K)$ in terms of the volume of
the convex body $K$ itself. Although no invariance with respect to a group
acting on the space of convex bodies is imposed, we prove that only two types
of operators appear: a family of operators having only cylinders over
$(n-1)$-dimensional convex bodies as images, and a second family consisting
essentially of 1-homogeneous operators. Using this description, we give
improvements of some known characterization results for the difference body.


title: Free ergodic $\mathbb{Z}^2$-systems and complexity

abstract:
  Using results relating the complexity of a two dimensional subshift to its
periodicity, we obtain an application to the well-known conjecture of
Furstenberg on a Borel probability measure on $[0,1)$ which is invariant under
both $x\mapsto px \pmod 1$ and $x\mapsto qx \pmod 1$, showing that any
potential counterexample has a nontrivial lower bound on its complexity.


title:
Efficiency of particle acceleration at interplanetary shocks:
  Statistical study of STEREO observations

abstract:
  Context. Among others, shocks are known to be accelerators of energetic
charged particles. However, many questions regarding the acceleration
efficiency and the required conditions are not fully understood. In particular,
the acceleration of electrons by shocks is often questioned. Aims. In this
study we determine the efficiency of interplanetary shocks for $<$100 keV
electrons, and for ions at $\sim$0.1 and $\sim$2 MeV energies, as measured by
the Solar Electron and Proton Telescope (SEPT) instruments aboard the twin
Solar Terrestrial Relations Observatory (STEREO) spacecraft. Methods. We employ
an online STEREO in situ shock catalog that lists all shocks observed between
2007 and mid 2014 (observed by STEREO A) and until end of 2013 (observed by
STEREO B). In total 475 shocks are listed. To determine the particle
acceleration efficiency of these shocks, we analyze the associated intensity
increases (shock spikes) during the shock crossings. For the near-relativistic
electrons, we take into account the issue of possible ion contamination in the
SEPT instrument. Results. The highest acceleration efficiency is found for low
energy ions (0.1 MeV), which show a shock-associated increase at 27% of all
shocks. The 2 MeV ions show an associated increase only during 5% of the shock
crossings. In the case of the electrons, the shocks are nearly ineffective.
Only five shock-associated electron increases were found, which correspond to
only 1% of all shock crossings.


title: Higher Gauge Theory with String 2-Groups

abstract:
  We give a complete and explicit description of the kinematical data of higher
gauge theory on principal 2-bundles with the string 2-group model of
Schommer-Pries as structure 2-group. We start with a self-contained review of
the weak 2-category Bibun of Lie groupoids, bibundles and bibundle morphisms.
We then construct categories internal to Bibun, which allow us to define
principal 2-bundles with 2-groups internal to Bibun as structure 2-groups.
Using these, we Lie-differentiate the 2-group model of the string group and we
obtain the well-known string Lie 2-algebra. Generalizing the differentiation
process, we find Maurer-Cartan forms leading us to higher non-abelian Deligne
cohomology, encoding the kinematical data of higher gauge theory together with
their (finite) gauge symmetries. We end by discussing an example of non-abelian
self-dual strings in this setting.


title: Stochastic Quasi-Newton Langevin Monte Carlo

abstract:
  Recently, Stochastic Gradient Markov Chain Monte Carlo (SG-MCMC) methods have
been proposed for scaling up Monte Carlo computations to large data problems.
Whilst these approaches have proven useful in many applications, vanilla
SG-MCMC might suffer from poor mixing rates when random variables exhibit
strong couplings under the target densities or big scale differences. In this
study, we propose a novel SG-MCMC method that takes the local geometry into
account by using ideas from Quasi-Newton optimization methods. These second
order methods directly approximate the inverse Hessian by using a limited
history of samples and their gradients. Our method uses dense approximations of
the inverse Hessian while keeping the time and memory complexities linear with
the dimension of the problem. We provide a formal theoretical analysis where we
show that the proposed method is asymptotically unbiased and consistent with
the posterior expectations. We illustrate the effectiveness of the approach on
both synthetic and real datasets. Our experiments on two challenging
applications show that our method achieves fast convergence rates similar to
Riemannian approaches while at the same time having low computational
requirements similar to diagonal preconditioning approaches.


title: The weak side of strong topological insulators

abstract:
  Strong topological insulators may have nonzero weak indices. The nonzero weak
indices allow for the existence of topologically protected helical states along
line defects of the lattice. If the lattice admits line defects that connect
opposite surfaces of a slab of such a "weak-and-strong" topological insulator,
these states effectively connect the surface states at opposite surfaces.
Depending on the phases accumulated along the dislocation lines, this
connection results in a suppression of in-plane transport and the opening of a
spectral gap or in an enhanced density of states and an increased conductivity.


title:
Improved empirical parametrizations of the $\gamma^\ast N \to N(1535)$
  transition amplitudes and the Siegert's theorem

abstract:
  Some empirical parametrizations of the $\gamma^\ast N \to N(1535)$ transition
amplitudes violates the Siegert's theorem, that relates the longitudinal and
the transverse amplitudes, in the pseudo-threshold limit (nucleon and resonance
at rest). In the case of the electromagnetic transition from the nucleon (mass
$M$) to the resonance $N(1525)$ (mass $M_R$), the Siegert's theorem is
sometimes expressed by the relation $|{\bf q}| A_{1/2}= \lambda S_{1/2}$ in the
pseudo-threshold limit, when the photon momentum $|{\bf q}|$ vanishes, and
$\lambda = \sqrt{2} (M_R -M)$. In this article, we argue that the Siegert's
theorem should be expressed by the relation $A_{1/2} = \lambda \frac{S_{1/2}}{
|{\bf q}|}$, in the limit $|{\bf q}| \to 0$. This result is a consequence of
the relation $S_{1/2} \propto |{\bf q}|$, when $|{\bf q}| \to 0$, as suggested
by the analysis of the transition form factors and by the orthogonality between
the nucleon and $N(1535)$ states. We propose then new empirical
parametrizations for the $\gamma^\ast N \to N(1535)$ helicity amplitudes, that
are consistent with the data and the Siegert's theorem. The proposed
parametrization follow closely the MAID2007 parametrization, except for a small
deviation in the amplitudes $A_{1/2}$ and $S_{1/2}$ when $Q^2 < 1.5$ GeV$^2$.


title: Davenport constant for commutative rings

abstract:
  The Davenport constant is one measure for how "large" a finite abelian group
is. In particular, the Davenport constant of an abelian group is the smallest
$k$ such that any sequence of length $k$ is reducible. This definition extends
naturally to commutative semigroups, and has been studied in certain finite
commutative rings. In this paper, we give an exact formula for the Davenport
constant of a general commutative ring in terms of its unit group.


title:
Composition operators and embedding theorems for some function spaces of
  Dirichlet series

abstract:
  We observe that local embedding problems for certain Hardy and Bergman spaces
of Dirichlet series are equivalent to boundedness of a class of composition
operators. Following this, we perform a careful study of such composition
operators generated by polynomial symbols $\varphi$ on a scale of Bergman--type
Hilbert spaces $\mathcal{D}_\alpha$. We investigate the optimal $\beta$ such
that the composition operator $\mathcal{C}_\varphi$ maps $\mathcal{D}_\alpha$
boundedly into $\mathcal{D}_\beta$. We also prove a new embedding theorem for
the non-Hilbertian Hardy space $\mathcal H^p$ into a Bergman space in the
half-plane and use it to consider composition operators generated by polynomial
symbols on $\mathcal{H}^p$, finding the first non-trivial results of this type.
The embedding also yields a new result for the functional associated to the
multiplicative Hilbert matrix.


title: Correlated Edge Overlaps in Multiplex Networks

abstract:
  We develop the theory of sparse multiplex networks with partially overlapping
links based on their local tree-likeness. This theory enables us to find the
giant mutually connected component in a two-layer multiplex network with
arbitrary correlations between connections of different types. We find that
correlations between the overlapping and non-overlapping links markedly change
the phase diagram of the system, leading to multiple hybrid phase transitions.
For assortative correlations we observe recurrent hybrid phase transitions.


title: Universal geometric coefficients for the four-punctured sphere

abstract:
  We construct universal geometric coefficients for the cluster algebra
associated to the four-punctured sphere and obtain, as a by-product, the
g-vectors of cluster variables. We also construct the rational part of the
mutation fan. These constructions rely on a classification of the allowable
curves (the curves which can appear in quasi-laminations). The classification
allows us to prove the Null Tangle Property for the four-punctured sphere, thus
adding this surface to a short list of surfaces for which this property is
known. The Null Tangle Property then implies that the shear coordinates of
allowable curves are the universal coefficients. We compute shear coordinates
explicitly to obtain universal geometric coefficients.


title: Be Stars as Seen Through Telescopes in Survey Mode (II)

abstract:
  The first half of the review dedicated to survey works on Be stars (Baade,
Martayan, and Rivinius, this vol.) put emphasis on what we can learn from
surveys about Be stars as a part of an environment, such as Be stars in
binaries, Be stars in different metalicities, or Be stars as part of a star
forming and then co-evolving group. This second half will rather concentrate on
the information that more focused surveys can give on a Be star, understood as
an individual object, and in this way attempts to bridge the gap between highly
detailed single star studies, and necessarily broad survey and catalog work.


title:
Topological insulator homojunctions including magnetic layers: the
  example of n-p type ($n$-QLs Bi$_2$Se$_3$/Mn-Bi$_2$Se$_3$) heterostructures

abstract:
  Homojunctions between Bi$_2$Se$_3$ and its Mn-doped phase are investigated as
a sample geometry to study the influence of spin degrees of freedom on
topological insulator properties. $n$ quintuple layers (QLs) of Bi$_2$Se$_3$
are grown ontop of Mn-doped Bi$_2$Se$_3$ by molecular beam epitaxy for $0\le n
\le 30\,$QLs, allowing to unhamperedly monitor the development of electronic
and topological properties by surface sensitive techniques like angle resolved
photoemission spectroscopy. With increasing $n$, a Mn-induced gap at the Dirac
point is gradually filled in an "hourglass" fashion to reestablish a
topological surface state at $n \sim 9\,$QLs. Our results suggest a competition
of upwards and downwards band bending effects due to the presence of an n-p
type interface, which can be used to tailor topological and quantum well states
independently.


title: Torus equivariant K-stability

abstract:
  It is conjectured that to test the K-polystability of a polarised variety it
is enough to consider test-configurations which are equivariant with respect to
a torus in the automorphism group. We prove partial results towards this
conjecture. We also show that it would give a new proof of the K-polystability
of constant scalar curvature polarised manifolds.


title: The Variable Line Width of Achernar

abstract:
  Spectroscopic observations of Achernar over the past decades, have shown the
photospheric line width, as measured by the rotational parameter $v \sin i$, to
vary in correlation with the emission activity. Here we present new
observations, covering the most recent activity phase, and further archival
data collected from the archives. The $v \sin i$ variation is confirmed. On the
basis of the available data it cannot be decided with certainty whether the
increased line width precedes the emission activity, i.e. is a signature of the
ejection mechanism, or postdates is, which would make it a signature of
re-accretion of some of the disk-material. However, the observed evidence leans
towards the re-accretion hypothesis. Two further stars showing the effect of
variable line width in correlation with emission activity, namely 66 Oph and
$\pi$ Aqr, are presented as well.


title:
Endoscopic lifting of simple supercuspidal representations of SO(2n+1)
  to GL(2n)

abstract:
  We compute the characters of simple supercuspidal representations of twisted
GL(2n) and standard SO(2n+1) over a p-adic field. Comparing them by the
endoscopic character relation, we determine the liftings of simple
supercuspidal representations of SO(2n+1) to GL(2n), under the assumption that
p is not equal to 2.


title: Entropy solutions for a traffic model with phase transitions

abstract:
  In this paper, we consider the two phases macroscopic traffic model
introduced in [P. Goatin, The Aw-Rascle vehicular traffic flow with phase
transitions, Mathematical and Computer Modeling 44 (2006) 287-303]. We first
apply the wave-front tracking method to prove existence and a priori bounds for
weak solutions. Then, in the case the characteristic field corresponding to the
free phase is linearly degenerate, we prove that the obtained weak solutions
are in fact entropy solutions \`a la Kruzhkov. The case of solutions attaining
values at the vacuum is considered. We also present an explicit numerical
example to describe some qualitative features of the solutions.


title:
Constraints on the unitarity triangle angle $\gamma$ from Dalitz plot
  analysis of $B^0 \to D K^+ \pi^-$ decays

abstract:
  The first study is presented of CP violation with an amplitude analysis of
the Dalitz plot of $B^0 \to D K^+ \pi^-$ decays, with $D \to K^+ \pi^-$, $K^+
K^-$ and $\pi^+ \pi^-$. The analysis is based on a data sample corresponding to
$3.0\,{\rm fb}^{-1}$ of $pp$ collisions collected with the LHCb detector. No
significant CP violation effect is seen, and constraints are placed on the
angle $\gamma$ of the unitarity triangle formed from elements of the
Cabibbo-Kobayashi-Maskawa quark mixing matrix. Hadronic parameters associated
with the $B^0 \to D K^*(892)^0$ decay are determined for the first time. These
measurements can be used to improve the sensitivity to $\gamma$ of existing and
future studies of the $B^0 \to D K^*(892)^0$ decay.


title:
Broad-band spectroscopy of the transient X-ray binary pulsar KS 1947+300
  during 2013 giant outburst: Detection of pulsating soft X-ray excess
  component

abstract:
  We present the results obtained from detailed timing and spectral studies of
the Be/X-ray binary pulsar KS 1947+300 during its 2013 giant outburst. We used
data from Suzaku observations of the pulsar at two epochs i.e. on 2013 October
22 (close to the peak of the outburst) and 2013 November 22. X-ray pulsations
at $\sim$18.81 s were clearly detected in the light curves obtained from both
observations. Pulse periods estimated during the outburst showed that the
pulsar was spinning up. The pulse profile was found to be single-peaked up to
$\sim$10 keV beyond which a sharp peak followed by a dip-like feature appeared
at hard X-rays. The dip-like feature has been observed up to $\sim$70 keV. The
1-110 keV broad-band spectroscopy of both observations revealed that the
best-fit model comprised of a partially absorbed Negative and Positive power
law with EXponential cutoff (NPEX) continuum model along with a blackbody
component for the soft X-ray excess and two Gaussian functions at 6.4 and 6.7
keV for emission lines. Both the lines were identified as emission from neutral
and He-like iron atom. To fit the spectra, we included the previously reported
cyclotron absorption line at 12.2 keV. From the spin-up rate, the magnetic
field of the pulsar was estimated to be $\sim$1.2$\times$10$^{12}$ G and found
to be comparable to that obtained from the detection of the cyclotron
absorption feature. Pulse-phase resolved spectroscopy revealed the pulsating
nature of the soft X-ray excess component in phase with the continuum flux.
This confirms that the accretion column and/or accretion stream are the most
probable regions of pulsar's soft X-ray excess emission. The presence of the
pulsating soft X-ray excess in phase with continuum emission may be the
possible reason for not observing the dip at soft X-rays.


title: OHANA, the AMBER/VLTI Snapshot Survey

abstract:
  We report on the OHANA interferometric snapshot survey, carried out by the
VLTI group at the Paranal observatory. It makes use of observing time not
useful for any other scheduled scientific or technical tasks in the sense of a
backup programme, to characterize the mass-loss for early-type stars. The
survey employs the combination of AMBER's high spectral and spatial resolution.
The spatially unresolved central object provides a reference frame for the
fringe properties observed in the light of the continuum.


title: Super-Resolved Retinal Image Mosaicing

abstract:
  The acquisition of high-resolution retinal fundus images with a large field
of view (FOV) is challenging due to technological, physiological and economic
reasons. This paper proposes a fully automatic framework to reconstruct retinal
images of high spatial resolution and increased FOV from multiple
low-resolution images captured with non-mydriatic, mobile and video-capable but
low-cost cameras. Within the scope of one examination, we scan different
regions on the retina by exploiting eye motion conducted by a patient guidance.
Appropriate views for our mosaicing method are selected based on optic disk
tracking to trace eye movements. For each view, one super-resolved image is
reconstructed by fusion of multiple video frames. Finally, all super-resolved
views are registered to a common reference using a novel polynomial
registration scheme and combined by means of image mosaicing. We evaluated our
framework for a mobile and low-cost video fundus camera. In our experiments, we
reconstructed retinal images of up to 30{\deg} FOV from 10 complementary views
of 15{\deg} FOV. An evaluation of the mosaics by human experts as well as a
quantitative comparison to conventional color fundus images encourage the
clinical usability of our framework.


title:
Kondo-induced hybrid topological insulator in two-dimensional electron
  system with a quadratic band crossing point

abstract:
  We investigate the Kondo effect in the two-dimensional electron system with a
non-trivial quadratic energy band crossing point. We show that the Kondo effect
can induce a new hybrid topological insulator phase which is a coexistence
state of the quantum anomalous Hall effect and the TRSbroken quantum spin Hall
effect. This hybrid topological insulator exhibits not only a quantized charge
Hall current but also a net spin current, which are localized at the edge
boundaries. This peculiar topological state arises due to the interplay of two
marginally relevant operators, i.e., the Kondo-coupling between the electrons
and the local magnetic moment and the electron-electron interaction in the
two-dimensional system.


title:
Waveforms in massive gravity and neutralization of giant black hole
  ringings

abstract:
  A distorted black hole radiates gravitational waves in order to settle down
in a smoother geometry. During that relaxation phase, a characteristic damped
ringing is generated. It can be theoretically constructed from both the black
hole quasinormal frequencies (which govern its oscillating behavior and its
decay) and the associated excitation factors (which determine intrinsically its
amplitude) by carefully taking into account the source of the distortion. In
the framework of massive gravity, the excitation factors of the Schwarzschild
black hole have an unexpected strong resonant behavior which, theoretically,
could lead to giant and slowly decaying ringings. If massive gravity is
relevant to physics, one can hope to observe these extraordinary ringings by
using the next generations of gravitational wave detectors. Indeed, they could
be generated by supermassive black holes if the graviton mass is not too small.
In fact, by focusing on the odd-parity $\ell=1$ mode of the Fierz-Pauli field,
we shall show here that such ringings are neutralized in waveforms due to (i)
the excitation of the quasibound states of the black hole and (ii) the
evanescent nature of the particular partial modes which could excite the
concerned quasinormal modes. Despite this, with observational consequences in
mind, it is interesting to note that the waveform amplitude is nevertheless
rather pronounced and slowly decaying (this effect is now due to the long-lived
quasibound states). It is worth noting also that, for very low values of the
graviton mass (corresponding to the weak instability regime for the black
hole), the waveform is now very clean and dominated by an ordinary ringing
which could be used as a signature of massive gravity.


title:
Observation of a subharmonic gap singularity in interlayer tunneling
  characteristics of Bi2Sr2CaCu2O8+d

abstract:
  A subharmonic structure in Josephson junctions appears due to Andreev
reflections within the junction. Here we report on experimental observation of
a subharmonic half-gap singularity in interlayer tunneling characteristics of a
layered high temperature superconductor Bi2Sr2CaCu2O8+d. The singularity is
most pronounced in optimally doped crystals and vanishes with decreasing
doping. It indicates existence of non-vanishing electronic density of states
and certain metallic properties in the intermediate BiO layers, which grows
stronger with increasing doping. This provides an additional coherent
interlayer transport channel and can explain a gradual transition from an
incoherent quasi-two-dimensional $c$-axis transport in underdoped to a coherent
metallic transport in overdoped cuprates. Furthermore, due to a very small
sub-gap current, the singularity allows unambiguous extraction of the
superconducting gap, without distortion by self-heating.


title: Progress in the calculation of nucleon transition form factors

abstract:
  We give a brief account of the Dyson-Schwinger and Faddeev-equation approach
and its application to nucleon resonances and their transition form factors. We
compare the three-body with the quark-diquark approach and present a
quark-diquark calculation for the low-lying nucleon resonances including
scalar, axialvector, pseudoscalar and vector diquarks. We also discuss the
timelike structure of transition form factors and highlight the advantages of
form factors over helicity amplitudes.


title: On the categorical entropy and the topological entropy

abstract:
  To an exact endofunctor of a triangulated category with a split-generator,
the notion of entropy is given by Dimitrov-Haiden-Katzarkov-Kontsevich, which
is a (possibly negative infinite) real-valued function of a real variable. In
this paper, we propose a conjecture which naturally generalizes the theorem by
Gromov-Yomdin, and show that the categorical entropy of a surjective
endomorphism of a smooth projective variety is equal to its topological
entropy. Moreover, we compute the entropy of autoequivalences of the derived
category in the case of the ample canonical or anti-canonical sheaf.


title: A Classical Solution of Massive Yang-Mills Fields

abstract:
  Recent researches on the solution of Schwinger-Dyson equations, as well as
lattice simulations of pure QCD, suggest that the gluon propagator is massive.
In this letter, we assume that the classical counterpart of this massive gluon
field may be represented with the equation of motion for Yang-Mills theory with
a mass term added. A new classical solution is given for this equation. It is
discussed that this solution may have some role in confinement.


title: Fate of the Tetraquark Candidate Zc(3900) from Lattice QCD

abstract:
  The possible exotic meson $Z_{c}(3900)$, found in $e^+ e^-$ reactions, is
studied by the method of coupled-channel scattering in lattice QCD. The
interaction among $\pi J/\psi$, $\rho \eta_{c}$ and $\bar{D}D^{*}$ channels is
derived from (2+1)-flavor QCD simulations at $m_{\pi}=410$-$700$ MeV. The
interaction is dominated by the off-diagonal $\pi J/\psi$-$\bar{D}D^{*}$ and
$\rho \eta_{c}$-$\bar{D}D^{*}$ couplings, which indicates that the
$Z_{c}(3900)$ is not a usual resonance but a threshold cusp.
Semi-phenomenological analyses with the coupled-channel interaction are
presented to confirm this conclusion.