title:
Backward Nested Descriptors Asymptotics with Inference on Stem Cell
  Differentiation

abstract:
  For sequences of random backward nested subspaces as occur, say, in dimension
reduction for manifold or stratified space valued data, asymptotic results are
derived. In fact, we formulate our results more generally for backward nested
families of descriptors (BNFD). Under rather general conditions, asymptotic
strong consistency holds. Under additional, still rather general hypotheses,
among them existence of a.s. local twice differentiable charts, asymptotic
joint normality of a BNFD can be shown. If charts factor suitably, this leads
to individual asymptotic normality for the last element, a principal nested
mean or a principal nested geodesic, say. It turns out that these results
pertain to principal nested spheres (PNS) and principal nested great subsphere
(PNGS) analysis by Jung et al. (2010) as well as to the intrinsic mean on a
first geodesic principal component (IMo1GPC) for manifolds and Kendall's shape
spaces. A nested bootstrap two-sample test is derived and illustrated with
simulations. In a study on real data, PNGS is applied to track early human
mesenchymal stem cell differentiation over a coarse time grid and, among
others, to locate a change point with direct consequences for the design of
further studies.


title: Laser printed nano-gratings: orientation and period peculiarities

abstract:
  Understanding of material behaviour at nanoscale under intense laser
excitation is becoming critical for future application of nanotechnologies.
Nanograting formation by linearly polarised ultra-short laser pulses has been
studied systematically in fused silica for various pulse energies at 3D laser
printing/writing conditions, typically used for the industrial fabrication of
optical elements. The period of the nanogratings revealed a dependence on the
orientation of the scanning direction. A tilt of the nanograting wave vector at
a fixed laser polarisation was also observed. The mechanism responsible for
this peculiar dependency of several features of the nanogratings on the writing
direction is qualitatively explained by considering the heat transport flux in
the presence of a linearly polarised electric field, rather than by temporal
and spatial chirp of the laser beam. The confirmed vectorial nature of the
light-matter interaction opens new control of material processing with
nanoscale precision.


title: Signature of frustrated moments in quantum critical CePd$_{1-x}$Ni$_x$Al

abstract:
  CePdAl with Ce $4f$ moments forming a distorted kagom\'e network is one of
the scarce materials exhibiting Kondo physics and magnetic frustration
simultaneously. As a result, antiferromagnetic (AF) order setting in at
$T_{\mathrm{N}} = 2.7$~K encompasses only two thirds of the Ce moments. We
report measurements of the specific heat, $C$, and the magnetic Gr\"uneisen
parameter, $\Gamma_{\rm mag}$, on single crystals of CePd$_{1-x}$Ni$_x$Al with
$x\leq 0.16$ at temperatures down to 0.05~K and magnetic fields $B$ up to
$8$~T. Field-induced quantum criticality for various concentrations is observed
with the critical field decreasing to zero at $x_c\approx 0.15$. Remarkably,
two-dimensional (2D) AF quantum criticality of Hertz-Millis-Moriya type arises
for $x=0.05$ and $x=0.1$ at the suppression of 3D magnetic order. Furthermore,
$\Gamma_{\rm mag}(B)$ shows an additional contribution near $2.5$~T for all
concentrations which is ascribed to correlations of the frustrated one third of
Ce moments.


title:
Stochastic Learning of Multi-Instance Dictionary for Earth Mover's
  Distance based Histogram Comparison

abstract:
  Dictionary plays an important role in multi-instance data representation. It
maps bags of instances to histograms. Earth mover's distance (EMD) is the most
effective histogram distance metric for the application of multi-instance
retrieval. However, up to now, there is no existing multi-instance dictionary
learning methods designed for EMD based histogram comparison. To fill this gap,
we develop the first EMD-optimal dictionary learning method using stochastic
optimization method. In the stochastic learning framework, we have one triplet
of bags, including one basic bag, one positive bag, and one negative bag. These
bags are mapped to histograms using a multi-instance dictionary. We argue that
the EMD between the basic histogram and the positive histogram should be
smaller than that between the basic histogram and the negative histogram. Base
on this condition, we design a hinge loss. By minimizing this hinge loss and
some regularization terms of the dictionary, we update the dictionary
instances. The experiments over multi-instance retrieval applications shows its
effectiveness when compared to other dictionary learning methods over the
problems of medical image retrieval and natural language relation
classification.


title: Probabilistic multi-catalogue positional cross-match

abstract:
  We lay the foundations of a statistical framework for multi-catalogue
cross-correlation and cross-identification based on explicit simplified
catalogue models. A proper identification process should rely on both
astrometric and photometric data. Under some conditions, the astrometric part
and the photometric part can be processed separately and merged a posteriori to
provide a single global probability of identification. The present paper
addresses almost exclusively the astrometrical part and specifies the proper
probabilities to be merged with photometric likelihoods.
  To select matching candidates in n catalogues, we used the Chi (or,
indifferently, the Chi-square) test with 2(n-1) degrees of freedom. We thus
call this cross-match a chi-match. In order to use Bayes' formula, we
considered exhaustive sets of hypotheses based on combinatorial analysis. The
volume of the Chi-test domain of acceptance -- a 2(n-1)-dimensional acceptance
ellipsoid -- is used to estimate the expected numbers of spurious associations.
We derived priors for those numbers using a frequentist approach relying on
simple geometrical considerations. Likelihoods are based on standard Rayleigh,
Chi and Poisson distributions that we normalized over the Chi-test acceptance
domain. We validated our theoretical results by generating and cross-matching
synthetic catalogues.
  The results we obtain do not depend on the order used to cross-correlate the
catalogues. We applied the formalism described in the present paper to build
the multi-wavelength catalogues used for the science cases of the ARCHES
(Astronomical Resource Cross-matching for High Energy Studies) project. Our
cross-matching engine is publicly available through a multi-purpose web
interface. In a longer term, we plan to integrate this tool into the CDS XMatch
Service.


title: Option-Based Pricing of Wrong Way Risk for CVA

abstract:
  The two main issues for managing wrong way risk (WWR) for the credit
valuation adjustment (CVA, i.e. WW-CVA) are calibration and hedging. Hence we
start from a novel model-free worst-case approach based on static hedging of
counterparty exposure with liquid options. We say "start from" because we
demonstrate that a naive worst-case approach contains hidden unrealistic
assumptions on the variance of the hazard rate (i.e. that it is infinite). We
correct this by making it an explicit (finite) parameter and present an
efficient method for solving the parametrized model optimizing the hedges. We
also prove that WW-CVA is theoretically, but not practically, unbounded. The
option-based hedges serve to significantly reduce (typically halve) practical
WW-CVA. Thus we propose a realistic and practical option-based worst case CVA.


title:
Classifying spaces for knots: New bridges between knot theory and
  algebraic number theory

abstract:
  A powerful way to study groups is via their actions on suitable spaces.
Classifying spaces for families of subgroups are a type of these spaces,
obtained by imposing some strict conditions on the fixed-point sets. We show
how in the framework of knot theory the notion of classifying spaces for
families pops out naturally and we provide explicit models for them. The study
of their topological properties hints at the existence of arcane connections
between knot theory and algebraic number theory. Trying to track these
connections, we discovered a behavioural analogy between the fundamental group
of our classifying spaces and the ideal class group of an algebraic number
field, a 9-term exact sequence for knots mimicking Poitou-Tate exact sequence
for algebraic number fields and, in some cases, a second analogy between the
first (co)homology group of the classifying spaces and the first Shafarevich
group of a number field extension.


title:
Stability of planar traveling waves in a Keller-Segel equation on an
  infinite strip domain

abstract:
  A simplified model of the tumor angiogenesis can be described by a
Keller-Segel equation \cite{FrTe,Le,Pe}. The stability of traveling waves for
the one dimensional system has recently been known by \cite{JinLiWa,LiWa}. In
this paper we consider the equation on the two dimensional domain $ (x, y) \in
  \mathbf R \times {\mathbf S^{\lambda}}$ for a small parameter $\lambda>0$
where $ \mathbf S^{\lambda}$ is the circle of perimeter $\lambda$. Then the
equation allows a planar traveling wave solution of invading types. We
establish the nonlinear stability of the traveling wave solution if the initial
perturbation is sufficiently small in a weighted Sobolev space without a
chemical diffusion. When the diffusion is present, we show a linear stability.
Lastly, we prove that any solution with our front conditions eventually becomes
planar under certain regularity conditions. The key ideas are to use the
Cole-Hopf transformation and to apply the Poincar\'{e} inequality to handle
with the two dimensional structure.


title: Classical and Quantum Logics with Multiple and a Common Lattice Models

abstract:
  We consider a proper propositional quantum logic and show that it has
multiple disjoint lattice models, only one of which is an orthomodular lattice
(algebra) underlying Hilbert (quantum) space. We give an equivalent proof for
the classical logic which turns out to have disjoint distributive and
non-distributive ortholattices as its models. In particular, we prove that both
classical and quantum logics are sound and complete with respect to each of
these lattices. We also show that there is one common non-orthomodular lattice
that is a model of both quantum and classical logics. In technical terms, that
enables us to run the same classical logic on both a digital (standard, two
subset, 0-1 bit) computer and on a non-digital (say, a six subset) computer
(with appropriate chips and circuits). With quantum logic, the same six element
common lattice can serve us as a benchmark for an efficient evaluation of
equations of bigger lattice models or theorems of the logic.


title:
Multi-type Galton-Watson processes with affinity-dependent selection
  applied to antibody affinity maturation

abstract:
  We analyze the interactions between division, mutation and selection in a
simplified evolutionary model, assuming that the population observed can be
classified into fitness levels. The construction of our mathematical framework
is motivated by the modeling of antibody affinity maturation of B-cells in
Germinal Centers during an immune response. This is a key process in adaptive
immunity leading to the production of high affinity antibodies against a
presented antigen. Our aim is to understand how the different biological
parameters affect the system's functionality. We identify the existence of an
optimal value of the selection rate, able to maximize the number of selected
B-cells for a given generation.


title:
AdS and dS black hole solutions in analogue gravity: The relativistic
  and non-relativistic cases

abstract:
  We show that Schwarzschild black hole solutions in asymptotically Anti-de
Sitter (AdS) and de Sitter (dS) spaces may, up to a conformal factor, be
reproduced in the framework of analogue gravity. The aforementioned derivation
is performed using relativistic and non-relativistic Bose-Einstein condensates.
In addition, we demonstrate that the (2+1) planar AdS black hole can be mapped
into the non-relativistic acoustic metric. Given that AdS black holes are
extensively employed in the gauge/gravity duality, we then comment on the
possibility to study the AdS/CFT correspondence and gravity/fluid duality from
an analogue gravity perspective.


title:
Phonon anharmonicity, lifetimes and thermal transport in
  CH$_3$NH$_3$PbI$_3$ from many-body perturbation theory

abstract:
  Lattice vibrations in CH$_3$NH$_3$PbI$_3$ are strongly interacting, with
double well instabilities present at the Brillouin zone boundary. Analysis
within a first-principles lattice dynamics framework reveals anharmonic
potentials with short phonon quasi-particle lifetimes and mean-free paths. The
phonon behaviour is distinct from the inorganic semiconductors GaAs and CdTe
where three-phonon interaction strengths are three orders of magnitude smaller.
The implications for the applications of hybrid halide perovskites arising from
thermal conductivity, band-gap deformation, and charge-carrier scattering
through electron-phonon coupling, are presented.


title: The effect of conformal symmetry on charged wormholes

abstract:
  This paper discusses the effect that conformal symmetry can have on a charged
wormhole. The analysis yields a physical interpretation of the conformal factor
in terms of the electric charge. The rate of change of the conformal factor
determines much of the outcome, which ranges from having no solution to
wormholes having either one or two throats.


title:
Error estimates on a finite volume method for diffusion problems with
  interface on Eulerian grids

abstract:
  The finite volume methods are frequently employed in the discretization of
diffusion problems with interface. In this paper, we firstly present a
vertex-centered MACH-like finite volume method for solving stationary diffusion
problems with strong discontinuity and multiple material cells on the Eulerian
grids. This method is motivated by Frese [No. AMRC-R-874, Mission Research
Corp., Albuquerque, NM, 1987]. Then, the local truncation error and global
error estimates of the degenerate five-point MACH-like scheme are derived by
introducing some new techniques. Especially under some assumptions, we prove
that this scheme can reach the asymptotic optimal error estimate $O(h^2 |\ln
h|)$ in the maximum norm. Finally, numerical experiments verify theoretical
results.


title: Exactly solvable interacting two-particle quantum graphs

abstract:
  We construct models of exactly solvable two-particle quantum graphs with
certain non-local two-particle interactions, establishing appropriate boundary
conditions via suitable self-adjoint realisations of the two-particle
Laplacian. Showing compatibility with the Bethe ansatz method, we calculate
quantisation conditions in the form of secular equations from which the spectra
can be deduced. We compare spectral statistics of some examples to well known
results in random matrix theory, analysing the chaotic properties of their
classical counterparts.


title: Efficient computation of Laguerre polynomials

abstract:
  An efficient algorithm and a Fortran 90 module (LaguerrePol) for computing
Laguerre polynomials $L^{(\alpha)}_n(z)$ are presented. The standard three-term
recurrence relation satisfied by the polynomials and different types of
asymptotic expansions valid for $n$ large and $\alpha$ small, are used
depending on the parameter region.
  Based on tests of contiguous relations in the parameter $\alpha$ and the
degree $n$ satisfied by the polynomials, we claim that a relative accuracy
close or better than $10^{-12}$ can be obtained using the module LaguerrePol
for computing the functions $L^{(\alpha)}_n(z)$ in the parameter range $z \ge
0$, $-1 < \alpha \le 5$, $n \ge 0$.


title: Cohen-Macaulay lexsegment complexes in arbitrary codimension

abstract:
  We characterize pure lexsegment complexes which are Cohen-Macaulay in
arbitrary codimension. More precisely, we prove that any lexsegment complex is
Cohen-Macaulay if and only if it is pure and its one dimensional links are
connected, and, a lexsegment flag complex is Cohen-Macaulay if and only if it
is pure and connected. We show that any non-Cohen-Macaulay lexsegment complex
is a Buchsbaum complex if and only if it is a pure disconnected flag complex.
For $t\ge 2$, a lexsegment complex is strictly Cohen-Macaulay in codimension
$t$ if and only if it is the join of a lexsegment pure disconnected flag
complex with a $(t-2)$-dimensional simplex. When the Stanley-Reisner ideal of a
pure lexsegment complex is not quadratic, the complex is Cohen-Macaulay if and
only if it is Cohen-Macaulay in some codimension. Our results are based on a
characterization of Cohen-Macaulay and Buchsbaum lexsegment complexes by
Bonanzinga, Sorrenti and Terai.


title: Dynamic beats fixed: On phase-based algorithms for file migration

abstract:
  We construct a deterministic 4-competitive algorithm for the online file
migration problem, beating the currently best 20-year-old, 4.086-competitive
MTLM algorithm by Bartal et al. (SODA 1997). Like MTLM, our algorithm also
operates in phases, but it adapts their lengths dynamically depending on the
geometry of requests seen so far. The improvement was obtained by carefully
analyzing a linear model (factor-revealing LP) of a single phase of the
algorithm. We also show that if an online algorithm operates in phases of fixed
length and the adversary is able to modify the graph between phases, then the
competitive ratio is at least 4.086.


title:
Information Measures, Inequalities and Performance Bounds for Parameter
  Estimation in Impulsive Noise Environments

abstract:
  Recent studies found that many channels are affected by additive noise that
is impulsive in nature and is best explained by heavy-tailed symmetric
alpha-stable distributions. Dealing with impulsive noise environments comes
with an added complexity with respect to the standard Gaussian environment: the
alpha-stable probability density functions have an infinite second moment and
the "nice" Hilbert space structure of the space of random variables having a
finite second moment is lost along with its tools and methodologies. This is
indeed the case in estimation theory where classical tools to quantify
performance of an estimator are tightly related to the assumption of finite
variance variables. In alpha-stable environments, expressions such as the mean
square error and the Cramer-Rao bound are hence problematic. In this work, we
tackle the parameter estimation problem in impulsive noise environments and
develop novel tools that are tailored to the alpha-stable and heavy-tailed
noise environments, tools that coincide with the standard ones adopted in the
Gaussian setup, namely a generalized "power" measure and a generalized Fisher
information. We generalize known information inequalities commonly used in the
Gaussian context: the de Bruijn's identity, the data processing inequality, the
Fisher information inequality, the isoperimetric inequality for entropies and
the Cramer-Rao bound. Additionally, we derive upper bounds on the differential
entropy of independent sums having a stable component. Finally, the new "power"
measure is used to shed some light on the additive alpha-stable noise channel
capacity in a setup that generalizes the linear average power constrained AWGN
channel. Our theoretical findings are paralleled with numerical evaluations of
various quantities and bounds using developed {\em Matlab} packages.


title:
An Upper Bound on the Sum Capacity of the Downlink Multicell Processing
  with Finite Backhaul Capacity

abstract:
  In this paper, we study upper bounds on the sum capacity of the downlink
multicell processing model with finite backhaul capacity for the simple case of
2 base stations and 2 mobile users. It is modelled as a two-user multiple
access diamond channel. It consists of a first hop from the central processor
to the base stations via orthogonal links of finite capacity, and the second
hop from the base stations to the mobile users via a Gaussian interference
channel. The converse is derived using the converse tools of the multiple
access diamond channel and that of the Gaussian MIMO broadcast channel. Through
numerical results, it is shown that our upper bound improves upon the existing
upper bound greatly in the medium backhaul capacity range, and as a result, the
gap between the upper bounds and the sum rate of the time-sharing of the known
achievable schemes is significantly reduced.


title: Functional Data Analysis by Matrix Completion

abstract:
  Functional data analyses typically proceed by smoothing, followed by
functional PCA. This paradigm implicitly assumes that rough variation is due to
nuisance noise. Nevertheless, relevant functional features such as
time-localised or short scale fluctuations may indeed be rough relative to the
global scale, but still smooth at shorter scales. These may be confounded with
the global smooth components of variation by the smoothing and PCA, potentially
distorting the parsimony and interpretability of the analysis. The goal of this
paper is to investigate how both smooth and rough variations can be recovered
on the basis of discretely observed functional data. Assuming that a functional
datum arises as the sum of two uncorrelated components, one smooth and one
rough, we develop identifiability conditions for the recovery of the two
corresponding covariance operators. The key insight is that they should possess
complementary forms of parsimony: one smooth and finite rank (large scale), and
the other banded and potentially infinite rank (small scale). Our conditions
elucidate the precise interplay between rank, bandwidth, and grid resolution.
Under these conditions, we show that the recovery problem is equivalent to
rank-constrained matrix completion, and exploit this to construct estimators of
the two covariances, without assuming knowledge of the true bandwidth or rank;
we study their asymptotic behaviour, and then use them to recover the smooth
and rough components of each functional datum by best linear prediction. As a
result, we effectively produce separate functional PCAs for smooth and rough
variation.


title: On the $A_{\alpha}$-spectra of trees

abstract:
  Let $G$ be a graph with adjacency matrix $A(G)$ and let $D(G)$ be the
diagonal matrix of the degrees of $G$. For every real $\alpha\in\left[
0,1\right],$ define the matrix $A_{\alpha}\left(G\right) $ as \[
A_{\alpha}\left(G\right) =\alpha D\left(G\right) +(1-\alpha)A\left(G\right) \]
where $0\leq\alpha\leq1$.
  This paper gives several results about the $A_{\alpha}$-matrices of trees. In
particular, it is shown that if $T_{\Delta}$ is a tree of maximal degree
$\Delta,$ then the spectral radius of $A_{\alpha}(T_{\Delta})$ satisfies the
tight inequality \[
\rho(A_{\alpha}(T_{\Delta}))<\alpha\Delta+2(1-\alpha)\sqrt{\Delta-1}. \] This
bound extends previous bounds of Godsil, Lov\'asz, and Stevanovi\'c. The proof
is based on some new results about the $A_{\alpha}$-matrices of Bethe trees and
generalized Bethe trees.
  In addition, several bounds on the spectral radius of $A_{\alpha}$ of general
graphs are proved, implying tight bounds for paths and Bethe trees.


title:
Towards Segmenting Consumer Stereo Videos: Benchmark, Baselines and
  Ensembles

abstract:
  Are we ready to segment consumer stereo videos? The amount of this data type
is rapidly increasing and encompasses rich information of appearance, motion
and depth cues. However, the segmentation of such data is still largely
unexplored. First, we propose therefore a new benchmark: videos, annotations
and metrics to measure progress on this emerging challenge. Second, we evaluate
several state of the art segmentation methods and propose a novel ensemble
method based on recent spectral theory. This combines existing image and video
segmentation techniques in an efficient scheme. Finally, we propose and
integrate into this model a novel regressor, learnt to optimize the stereo
segmentation performance directly via a differentiable proxy. The regressor
makes our segmentation ensemble adaptive to each stereo video and outperforms
the segmentations of the ensemble as well as a most recent RGB-D segmentation
technique.


title: Plastikstufe with toric core

abstract:
  Plastikstufes and overtwistedness for higher-dimensional contact manifolds
are studied in this paper. It is proved that a contact structure is overtwisted
if and only if there exists a small plastikstufe with toric core that has
trivial rotation.


title:
Moran-type bounds for the fixation probability in a frequency-dependent
  Wright-Fisher model

abstract:
  We study stochastic evolutionary game dynamics in a population of finite
size. Individuals in the population are divided into two dynamically evolving
groups. The structure of the population is formally described by a
Wright-Fisher type Markov chain with a frequency dependent fitness. In a strong
selection regime that favors one of the two groups, we obtain qualitatively
matching lower and upper bounds for the fixation probability of the
advantageous population. In the infinite population limit we obtain an exact
result showing that a single advantageous mutant can invade an infinite
population with a positive probability. We also give asymptotically sharp
bounds for the fixation time distribution.


title: How we pass from semigroups to hypersemigroups

abstract:
  The aim of writing this paper is given in the title. The results on
semigroups can be easily transferred to hyper-semigroups in the way indicated
in the present paper.


title: The Second Discriminant of a Univariate Polynomial

abstract:
  We define the second discriminant $D_2$ of a univariate polynomial $f$ of
degree greater than $2$ as the product of the linear forms $2\,r_k-r_i-r_j$ for
all triples of roots $r_i, r_k, r_j$ of $f$ with $i<j$ and $j\neq k, k\neq i$.
$D_2$ vanishes if and only if $f$ has at least one root which is equal to the
average of two other roots. We show that $D_2$ can be expressed as the
resultant of $f$ and a determinant formed with the derivatives of $f$,
establishing a new relation between the roots and the coefficients of $f$. We
prove several notable properties and present an application of $D_2$.


title:
Domain structure of ultrathin ferromagnetic elements in the presence of
  Dzyaloshinskii-Moriya interaction

abstract:
  Recent advances in nanofabrication make it possible to produce multilayer
nanostructures composed of ultrathin film materials with thickness down to a
few monolayers of atoms and lateral extent of several tens of nanometers. At
these scales, ferromagnetic materials begin to exhibit unusual properties, such
as perpendicular magnetocrystalline anisotropy and antisymmetric exchange, also
referred to as Dzyaloshinskii-Moriya interaction (DMI), because of the
increased importance of interfacial effects. The presence of surface DMI has
been demonstrated to fundamentally alter the structure of domain walls. Here we
use the micromagnetic modeling framework to analyse the existence and structure
of chiral domain walls, viewed as minimizers of a suitable micromagnetic energy
functional. We explicitly construct the minimizers in the one-dimensional
setting, both for the interior and edge walls, for a broad range of parameters.
We then use the methods of {$\Gamma$}-convergence to analyze the asymptotics of
the two-dimensional mag- netization patterns in samples of large spatial extent
in the presence of weak applied magnetic fields.

categories: cond-mat.mes-hall math-ph math.MP nlin.PS


title: Rate of Convergence of the Bundle Method

abstract:
  We prove that the bundle method for nonsmooth optimization achieves solution
accuracy $\varepsilon$ in at most
$\mathcal{O}\big(\ln(1/\varepsilon)/\varepsilon\big)$ iterations, if the
function is strongly convex. The result is true for the versions of the method
with multiple cuts and with cut aggregation.


title:
An Online Universal Classifier for Binary, Multi-class and Multi-label
  Classification

abstract:
  Classification involves the learning of the mapping function that associates
input samples to corresponding target label. There are two major categories of
classification problems: Single-label classification and Multi-label
classification. Traditional binary and multi-class classifications are
sub-categories of single-label classification. Several classifiers are
developed for binary, multi-class and multi-label classification problems, but
there are no classifiers available in the literature capable of performing all
three types of classification. In this paper, a novel online universal
classifier capable of performing all the three types of classification is
proposed. Being a high speed online classifier, the proposed technique can be
applied to streaming data applications. The performance of the developed
classifier is evaluated using datasets from binary, multi-class and multi-label
problems. The results obtained are compared with state-of-the-art techniques
from each of the classification types.


title: Theory overview of electroweak physics at hadron colliders

abstract:
  This contribution summarizes some of the important theoretical progress that
has been made in the arena of electroweak physics at hadron colliders. The
focus is on developments that have sharpened theoretical predictions for final
states produced through electroweak processes. Special attention is paid to new
results that have been presented in the last year, since LHCP2015, as well as
on key issues for future measurements at the LHC.


title: Graph-Based Active Learning: A New Look at Expected Error Minimization

abstract:
  In graph-based active learning, algorithms based on expected error
minimization (EEM) have been popular and yield good empirical performance. The
exact computation of EEM optimally balances exploration and exploitation. In
practice, however, EEM-based algorithms employ various approximations due to
the computational hardness of exact EEM. This can result in a lack of either
exploration or exploitation, which can negatively impact the effectiveness of
active learning. We propose a new algorithm TSA (Two-Step Approximation) that
balances between exploration and exploitation efficiently while enjoying the
same computational complexity as existing approximations. Finally, we
empirically show the value of balancing between exploration and exploitation in
both toy and real-world datasets where our method outperforms several
state-of-the-art methods.


title:
Deep data mining in a real space: Separation of intertwined electronic
  responses in a lightly-doped BaFe2As2

abstract:
  Electronic interactions present in material compositions close to the
superconducting dome play a key role in the manifestation of high-Tc
superconductivity. In many correlated electron systems, however, the parent or
underdoped states exhibit strongly inhomogeneous electronic landscape at the
nanoscale that may be associated with competing, coexisting, or intertwined
chemical disorder, strain, magnetic, and structural order parameters. Here we
demonstrate an approach based on a combination of scanning tunneling
microscopy/spectroscopy (STM/S) and advanced statistical learning for an
automatic separation and extraction of statistically significant electronic
behaviors in the spin density wave (SDW) regime of a lightly (~1%) gold-doped
BaFe2As2. We show that the decomposed STS spectral features have a direct
relevance to fundamental physical properties of the system, such as SDW-induced
gap, pseudogap-like state, and impurity resonance states.


title:
Shell plus pairing effect arguments for cluster preformation at the
  nuclear surface in cold fission

abstract:
  In 1928 G. Gamow as well as Condon and Gurney gave the first explanation of
alpha decay as a quantum tunnelling of a preformed particle at the nuclear
surface. Soon after experimental discovery in 1984 by Rose and Jones of cluster
radioactivity, confirming earlier (1980) predictions by Sandulescu, Poenaru and
W. Greiner, a microscopic theory also explained the phenomenon in a similar
way. Here we show for the first time that in a spontaneous cold fission process
the shell plus pairing corrections calculated with Strutinsky's procedure may
give a strong argument for preformation of a light fission fragment near the
nuclear surface. It is obtained when the radius of the light fragment, $R_2$,
is increased linearly with the separation distance, $R$, of the two fragments,
while for $R_2=$~constant one gets the well known two hump potential barrier.


title: Effects of Finite-time Singularities on Gravitational Waves

abstract:
  We analyze the impact of finite-time singularities on gravitational waves, in
the context of $F(R)$ gravity. We investigate which singularities are allowed
to occur during the inflationary era, when gravitational waves are considered,
and we discuss the quantitative implications of each allowed singularity. As we
show, only a pressure singularity, the so-called Type II and also a Type IV
singularity are allowed to occur during the inflationary era. In the case of a
Type II, the resulting amplitude of the gravitational wave is zero or almost
zero, hence this pressure singularity has a significant impact on the
primordial gravitational waves. The case of a Type IV singularity is more
interesting since as we show, the singularity has no effect on the amplitude of
the gravitational waves. Therefore, this result combined with the fact that the
Type IV singularity affects only the dynamics of inflation, leads to the
conclusion that the Universe passes smoothly through a Type IV singularity.


title:
A GKM Description of the Equivariant Coinvariant Ring of a Pseudo
  Reflection Group

abstract:
  We identify the equivariant coinvariant ring of a pseudo-reflection group
with its image under the localization map. We then show that this image can be
realized as the equivariant cohomology of a sort linear hypergraph, analogous
to a GKM 1-skeleton.


title:
Integrating Agent-based Programming with Elementary Science: The Role of
  Sociomathematical Norms

abstract:
  How can elementary grade teachers integrate programming and computational
thinking with the science curriculum? To answer this question, we present
results from a long-term, design-based, microgenetic study where 1) agent-based
programming using ViMAP was integrated with existing elementary science
curricula and 2) lessons were taught by the classroom teacher. We present an
investigation of the co-development of children's computational thinking and
scientific modeling and show that the integration of programming with
scientific modeling can be supported by the development of sociomathematical
norms for designing "mathematically good" computational models.


title: Inverse Design for Self Assembly via On-the-Fly Optimization

abstract:
  Inverse methods of statistical mechanics have facilitated the discovery of
pair potentials that stabilize a wide variety of targeted lattices at zero
temperature. However, such methods are complicated by the need to compare,
within the optimization framework, the energy of the desired lattice to all
possibly relevant competing structures, which are not generally known in
advance. Furthermore, ground-state stability does not guarantee that the target
will readily assemble from the fluid upon cooling from higher temperature.
Here, we introduce a molecular dynamics simulation-based, optimization design
strategy that iteratively and systematically refines the pair interaction
according to the fluid and crystalline structural ensembles encountered during
the assembly process. We successfully apply this probabilistic,
machine-learning approach to the design of repulsive, isotropic pair potentials
that assemble into honeycomb, kagome, square, rectangular, truncated square and
truncated hexagonal lattices.


title:
Joint Caching and Pricing Strategies for Popular Content in Information
  Centric Networks

abstract:
  We develop an analytical framework for distribution of popular content in an
Information Centric Network (ICN) that comprises of Access ICNs, a Transit ICN
and a Content Provider. Using a generalized Zipf distribution to model content
popularity, we devise a game theoretic approach to jointly determine caching
and pricing strategies in such an ICN. Under the assumption that the caching
cost of the access and transit ICNs is inversely proportional to popularity, we
show that the Nash caching strategies in the ICN are 0-1 (all or nothing)
strategies. Further, for the case of symmetric Access ICNs, we show that the
Nash equilibrium is unique and the caching policy (0 or 1) is determined by a
threshold on the popularity of the content (reflected by the Zipf probability
metric), i.e., all content more popular than the threshold value is cached. We
also show that the resulting threshold of the Access and Transit ICNs, as well
as all prices can be obtained by a decomposition of the joint caching and
pricing problem into two independent caching only and pricing only problems.


title:
A $q$-Queens Problem. V. Some of Our Favorite Pieces: Queens, Bishops,
  Rooks, and Nightriders

abstract:
  Parts I-IV showed that the number of ways to place $q$ nonattacking queens or
similar chess pieces on an $n\times n$ chessboard is a quasipolynomial function
of $n$ whose coefficients are essentially polynomials in $q$. For partial
queens, which have a subset of the queen's moves, we proved complete formulas
for these counting quasipolynomials for small numbers of pieces and other
formulas for high-order coefficients of the general counting quasipolynomials.
We found some upper and lower bounds for the periods of those quasipolynomials
by calculating explicit denominators of vertices of the inside-out polytope.
  Here we discover more about the counting quasipolynomials for partial queens,
both familiar and strange, and the nightrider and its subpieces, and we compare
our results to the empirical formulas found by Kot\v{e}\v{s}ovec. We prove some
of Kot\v{e}\v{s}ovec's formulas and conjectures about the quasipolynomials and
their high-order coefficients, and in some instances go beyond them.


title:
Anisotropic residual based a posteriori mesh adaptation in 2D: element
  based approach

abstract:
  An element based adaptation method is developed for an anisotropic a
posteriori error estimator. The adaptation does not make use of a metric, but
instead equidistributes the error over elements using local mesh modifications.
Numerical results are reported, comparing with three popular anisotropic
adaptation methods currently in use. It was found that the new method gives
favourable results for controlling the energy norm of the error in terms of
degrees of freedom at the cost of increased CPU usage. Additionally, we
considered a new $L^2$ variant of the estimator. The estimator is shown to be
conditionally equivalent to the exact $L^2$ error. We provide examples of
adapted meshes with the $L^2$ estimator, and show that it gives greater control
of the $L^2$ error compared with the original estimator.


title:
All-phononic Amplification in Coupled Cantilever Arrays based on Gap
  Soliton Dynamics

abstract:
  We present a mechanism of amplification of phonons by phonons on the basis of
nonlinear band-gap transmission phenomenon. As a concept the idea may be
applied to the various number of systems, however we introduce the specific
idea of creating amplification scenario in the chain of coupled cantilever
arrays. One chain is driven at the constant frequency located in the upper band
of the ladder system, thus no wave enters the system. However the frequency is
specifically chosen to be very close to the maximum value of frequency
corresponding to dispersion relation of the system. Amplification scenario
happens when a counter phase pulse of same frequency with a small amplitude is
introduced to the second chain. If both signals exceed a threshold amplitude
for the band-gap transmission a large amplitude soliton enters the system -
therefore we have an amplifier. Although the concept may be applied in a
variety of contexts - all optical or all-magnonic systems, we choose the system
of coupled cantilever arrays and represent a clear example of the application
of presented conceptual idea. Logical operations is the other probable field,
where such mechanism could be used, which might significantly broaden the
horizon of considered applications of band-gap soliton dynamics.


title:
Spectral Efficiency Bounds for Interference-Limited SVD-MIMO Cellular
  Communication Systems

abstract:
  The ergodic spectral efficiency (SE) in interference-limited multiple-input
multiple-output (MIMO) downlink cellular systems is characterized based on
stochastic geometry. A single user is served by using singular value
decomposition precoding and combining. By approximating the expectations of the
channel eigenvalues, we derive upper and lower bounds on the ergodic SE. The
obtained upper bound is the best possible system-level performance of any MIMO
strategy in non-cooperative cellular networks. We validate our analytical
results through simulation. We also conjecture that there exists the optimal
number of streams being proportional to the pathloss exponent.


title: Exciting with Quantum Light. II. Exciting a two-level system

abstract:
  We study the excitation of a two-level system (2LS) by quantum light, thereby
bringing our previous studies~(see part~I. of this series) to a target that is
quantum itself. While there is no gain for the quantum state of the target as
compared to driving it with classical light, its dynamical features, such as
antibunching, can be improved. We propose a chain of two-level systems, i.e.,
setting the emission of each 2LS as the driving source of the following one, as
an arrangement to provide better single-photon sources. At a fundamental level,
we discuss the notion of strong-coupling between quantum light from a source
and its target, and the several versions of the Mollow triplet that follow from
various types of driving light. We discuss the Heitler effect of antibunched
photons from the scattered light off a laser.


title: Etch-Tuning and Design of Silicon Nitride Photonic Crystal Reflectors

abstract:
  By patterning a freestanding dielectric membrane into a photonic crystal
reflector (PCR), it is possible to resonantly enhance its normal-incidence
reflectivity, thereby realizing a thin, single-material mirror. In many PCR
applications, the operating wavelength (e.g. that of a low-noise laser or
emitter) is not tunable, imposing tolerances on crystal geometry that are not
reliably achieved with standard nanolithography. Here we present a gentle
technique to finely tune the resonant wavelength of a SiN PCR using iterative
hydrofluoric acid etches. With little optimization, we achieve a 57-nm-thin
photonic crystal having an operating wavelength within 0.15 nm (0.04 resonance
linewidths) of our target (1550 nm). Our thin structure exhibits a broader and
less pronounced transmission dip than is predicted by plane wave simulations,
and we identify two effects leading to these discrepancies, both related to the
divergence angle of a collimated laser beam. To overcome this limitation in
future devices, we distill a series of simulations into a set of general design
considerations for realizing robust, high-reflectivity resonances.


title: Soft Phonon Mode Dynamics in Aurivillius Type Structures

abstract:
  We report the dynamics of soft phonon modes and their role towards the
various structural transformations in Aurivillius materials by employing
terahertz frequency-domain spectroscopy, atomic pair distribution function
analysis, and first-principles calculations. We have chosen Bi4Ti3O12 as a
model system and identified soft phonon modes associated with the paraelectric
tetragonal to the ferroelectric monoclinic transition. Three soft phonon modes
have been discovered which exhibit a strong temperature dependence. We have
determined that the anharmonicity in Bi-O bonds plays a significant role in
phonon softening and that Bi cations play an important role in the emergence of
ferroelectricity.


title: Restrained Dark $U(1)_d$ at Low Energies

abstract:
  We investigate a spontaneously broken $U(1)_d$ gauge symmetry with a
muon-specific dark Higgs. Our first goal is to verify how the presence of a new
dark Higgs, $\phi$, and a dark gauge boson, $V$, can simultaneously face the
anomalies from the muon magnetic moment and the proton charge radius. Secondly,
by assuming that $V$ must decay to an electron-positron pair, we explore the
corresponding parameter space determined with the low energy constraints coming
from $ K \to \mu X$, electron $(g-2)_e$, $K \to \mu \nu_\mu e^+ e^-$, $K \to
\mu \nu_\mu \mu^+ \mu^-$, $\tau \to \nu_\tau \mu \nu_\mu e^+ e^-$. We focus in
the scenario where the $V$ mass is below $ \sim 2 m_\mu$ and the $\phi$ mass
runs from few MeV till $250$ MeV, with V-photon mixing of the order $
\sim\mathcal{O}(10^{-3})$. Among weak process at low energies, we check the
influence of the new light vector on kaon decays as well as on the scattering
$e^+ e^- \rightarrow \mu^+ \mu^- e^+ e^-$ and discuss the impact of the dark
Higgs on $e^+ e^- \rightarrow \mu^+ \mu^- \mu^+ \mu^- $. Finally, we consider
contributions of the V-photon mixing in the decays $\pi^0 \to \gamma e^+ e^-$,
$\eta \to \gamma e^+ e^-$, $\rho \to \pi e^+ e^-$, $K^* \to K e^+ e^-$ and
$\phi (1020) \to \eta e^+ e^-$.


title: Adaptation in log-concave density estimation

abstract:
  The log-concave maximum likelihood estimator of a density on the real line
based on a sample of size $n$ is known to attain the minimax optimal rate of
convergence of $O(n^{-4/5})$ with respect to, e.g., squared Hellinger distance.
In this paper, we show that it also enjoys attractive adaptation properties, in
the sense that it achieves a faster rate of convergence when the logarithm of
the true density is $k$-affine (i.e.\ made up of $k$ affine pieces), provided
$k$ is not too large. Our results use two different techniques: the first
relies on a new Marshall's inequality for log-concave density estimation, and
reveals that when the true density is close to log-linear on its support, the
log-concave maximum likelihood estimator can achieve the parametric rate of
convergence in total variation distance. Our second approach depends on local
bracketing entropy methods, and allows us to prove a sharp oracle inequality,
which implies in particular that the rate of convergence with respect to
various global loss functions, including Kullback--Leibler divergence, is
$O\bigl(\frac{k}{n}\log^{5/4} n\bigr)$ when the true density is log-concave and
its logarithm is close to $k$-affine.


title:
Convergence analysis of variants of the averaged alternating modified
  reflections method

abstract:
  This paper presents new variants of the averaged alternating modified
reflections (AAMR) method for the best approximation problem. Under a mild
constraint qualification, we first show its weak convergence and then establish
a convergence rate. Furthermore, under a standard interior-point-like
condition, we show that the method has a finite termination property.


title:
Limits for the graphene on ferroelectric domain wall p-n-junction
  rectifier for different regimes of current

abstract:
  Here we present the theory of the conductivity of pn junction (pnJ) in
graphene channel, placed on ferroelectric substrate, caused by ferroelectric
domain wall (FDW) for the case of arbitrary current regime: from ballistic to
diffusive one. We calculated the ratio of the pnJ conductions for opposite
polarities of voltages, applied to source and drain electrodes of the
channel,G+/G- as the function of the graphene channel length L, electron mean
free path {\lambda} and ferroelectric substrate permittivity. We have
demonstrated, that the small values of G+/G-(0.1 and smaller), which correspond
to efficient graphene pnJ based rectifier, can be obtained for the
ferroelectrics with high and for the ratios of L/{\lambda}~1 or smaller.
However, for ferroelectrics with extremely high permittivity(relaxor or
PbZrxTi1-xO3 with composition x near the morphotropic phase boundary x=0.52)
the ratio G+/G- can be essentially smaller then unity for the case of a
pronounced diffusive regime of current as well. This makes the ferroelectric
substrates with high permittivity excellent candidates for the fabrication of
new generation of rectifiers based on the graphene pnJ. Temperature effect on
ratio was studied within Landau-Ginzburg-Devonshire approach. We have
demonstrated that rectifying properties of the graphene pnJ become better in
the vicinity of Curie temperature. However, for the temperatures higher than
Curie temperature the rectifying effect vanishes due to the ferroelectric
polarization disappearance.


title: Identifiability of linear dynamic networks

abstract:
  Dynamic networks are structured interconnections of dynamical systems
(modules) driven by external excitation and disturbance signals. In order to
identify their dynamical properties and/or their topology consistently from
measured data, we need to make sure that the network model set is identifiable.
We introduce the notion of network identifiability, as a property of a
parameterized model set, that ensures that different network models can be
distinguished from each other when performing identification on the basis of
measured data. Different from the classical notion of (parameter)
identifiability, we focus on the distinction between network models in terms of
their transfer functions. For a given structured model set with a pre-chosen
topology, identifiability typically requires conditions on the presence and
location of excitation signals, and on presence, location and correlation of
disturbance signals. Because in a dynamic network, disturbances cannot always
be considered to be of full-rank, the reduced-rank situation is also covered,
meaning that the number of driving white noise processes can be strictly less
than the number of disturbance variables. This includes the situation of having
noise-free nodes.


title:
Data Mining Graphene: Correlative Analysis of Structure and Electronic
  Degrees of Freedom in Graphenic Monolayers with Defects

abstract:
  The link between changes in the material crystal structure and its
mechanical, electronic, magnetic, and optical functionalities - known as the
structure-property relationship - is the cornerstone of the contemporary
materials science research. The recent advances in scanning transmission
electron and scanning probe microscopies (STEM and SPM) have opened an
unprecedented path towards examining the materials structure-property
relationships on the single-impurity and atomic-configuration levels. Lacking,
however, are the statistics-based approaches for cross-correlation of structure
and property variables obtained in different information channels of the STEM
and SPM experiments. Here we have designed an approach based on a combination
of sliding window fast Fourier transform, Pearson correlation matrix, and
linear and kernel canonical correlation, to study a relationship between
lattice distortions and electron scattering from SPM data on graphene with
defects. Our analysis revealed that the strength of coupling to strain is
altered between different scattering channels, which can explain coexistence of
several quasiparticle interference patterns in nanoscale regions of interest.
In addition, the application of kernel functions allowed us to extract a
non-linear component of the relationship between the lattice strain and
scattering intensity in graphene. The outlined approach can be further utilized
towards analyzing correlations in various multi-modal imaging techniques where
the information of interest is spatially distributed and generally has a
complex multidimensional nature.


title:
Deep-Anomaly: Fully Convolutional Neural Network for Fast Anomaly
  Detection in Crowded Scenes

abstract:
  The detection of abnormal behaviours in crowded scenes has to deal with many
challenges. This paper presents an efficient method for detection and
localization of anomalies in videos. Using fully convolutional neural networks
(FCNs) and temporal data, a pre-trained supervised FCN is transferred into an
unsupervised FCN ensuring the detection of (global) anomalies in scenes. High
performance in terms of speed and accuracy is achieved by investigating the
cascaded detection as a result of reducing computation complexities. This
FCN-based architecture addresses two main tasks, feature representation and
cascaded outlier detection. Experimental results on two benchmarks suggest that
detection and localization of the proposed method outperforms existing methods
in terms of accuracy.


title:
Updating the Number of Crossings in Rectilinear Drawings of the Complete
  Graph

abstract:
  Let $S$ be a set of $n$ points in general position in the plane. Join every
pair of points in $S$ with a straight line segment. Let $\overline{cr}(S)$ be
number of pairs of these edges that intersect in their interior. Suppose that
this number is known. In this paper we consider the problem of computing
$\overline{cr}(S')$, where $S'$ comes from adding, deleting or moving a point
from $S$.


title:
Advances in solving the two-fermion homogeneous Bethe-Salpeter equation
  in Minkowski space

abstract:
  Actual solutions of the Bethe-Salpeter equation for a two-fermion bound
system are becoming available directly in Minkowski space, by virtue of a novel
technique, based on the so-called Nakanishi integral representation of the
Bethe-Salpeter amplitude and improved by expressing the relevant momenta
through light-front components, i.e. $k^\pm=k^0 \pm k^3$. We solve a crucial
problem that widens the applicability of the method to real situations by
providing an analytically exact treatment of the singularities plaguing the
two-fermion problem in Minkowski space, irrespective of the complexity of the
irreducible Bethe-Salpeter kernel. This paves the way for feasible numerical
investigations of relativistic composite systems, with any spin degrees of
freedom. We present a thorough comparison with existing numerical results,
evaluated in both Minkowski and Euclidean space, fully corroborating our
analytical treatment, as well as fresh light-front amplitudes illustrating the
potentiality of non perturbative calculations performed directly in Minkowski
space.


title:
Determining Optimal Stop-Loss Thresholds via Bayesian Analysis of
  Drawdown Distributions

abstract:
  Stop-loss rules are often studied in the financial literature, but the
stop-loss levels are seldom constructed systematically. In many papers, and
indeed in practice as well, the level of the stops is too often set
arbitrarily. Guided by the overarching goal in finance to maximize expected
returns given available information, we propose a natural method by which to
systematically select the stop-loss threshold by analyzing the distribution of
maximum drawdowns. We present results for an hourly trading strategy with two
variations on the construction.


title: Nanoscale force sensor and actuator with carbon-nanotube network

abstract:
  Actuators at the nanoscale are assuming great important in todays shrinking
electronics industry where a system-on-chip approach is used to integrate
multi-functional systems and devices. Integration of sensors, actuators,
information processing, and storage have become extremely important, more so at
the sub-micrometer scale. Here we utilized vertically aligned carbon nanotube
forests bonded onto a piezoelectric substrate to provide sensing of nanoscale
forces and actuation on the same platform. This is a demonstration of
integration of two important functions using the functionality of
nanomaterials. This has immediate utility in many areas including outer space
exploration, portable consumer electronics, embedded systems, etc.


title: Scale-Bridging Model Development for Coal Particle Devolatilization

abstract:
  When performing large-scale, high-performance computations of multi-physics
applications, it is common to limit the complexity of physics sub-models
comprising the simulation. For a hierarchical system of coal boiler simulations
a scale-bridging model is constructed to capture characteristics appropriate
for the application-scale from a detailed coal devolatilization model. Such
scale-bridging allows full descriptions of scale-applicable physics, while
functioning at reasonable computational costs. This study presents a variation
on multi-fidelity modeling with a detailed physics model, the chemical
percolation devolatilization model, being used to calibrate a scale-briding
model for the application of interest. The application space provides essential
context for designing the scale-bridging model by defining scales, determining
requirements and weighting desired characteristics. A single kinetic reaction
equation with functional yield model and distributed activation energy is
implemented to act as the scale-bridging model-form. Consistency constraints
are used to locate regions of the scale-bridging model's parameter-space that
are consistent with the uncertainty identified within the detailed model.
Ultimately, the performance of the scale-bridging model with consistent
parameter-sets was assessed against desired characteristics of the detailed
model and found to perform satisfactorily in capturing thermodynamic trends and
kinetic timescales for the desired application-scale. Framing the process of
model-form selection within the context of calibration and uncertainty
quantification allows the credibility of the model to be established.


title: Entanglement Growth after a Global Quench in Free Scalar Field Theory

abstract:
  We compute the entanglement and R\'enyi entropy growth after a global quench
in various dimensions in free scalar field theory. We study two types of
quenches: a boundary state quench and a global mass quench. Both of these
quenches are investigated for a strip geometry in 1, 2, and 3 spatial
dimensions, and for a spherical geometry in 2 and 3 spatial dimensions. We
compare the numerical results for massless free scalars in these geometries
with the predictions of the analytical quasiparticle model based on EPR pairs,
and find excellent agreement in the limit of large region sizes. At subleading
order in the region size, we observe an anomalous logarithmic growth of
entanglement coming from the zero mode of the scalar.

categories: hep-th astro-ph.CO cond-mat.stat-mech quant-ph


title:
Measurement of the total and differential inclusive B+ hadron cross
  sections in pp collisions at sqrt(s) = 13 TeV

abstract:
  The differential cross sections for inclusive production of B+ hadrons are
measured as a function of the B+ transverse momentum pT[B] and rapidity y[B] in
pp collisions at a centre-of-mass energy of 13 TeV, using data collected by the
CMS experiment that correspond to an integrated luminosity of 49.4 inverse
picobarns. The measurement uses the exclusive decay channel B+ to J/psi K+,
with J/psi mesons that decay to a pair of muons. The results show a reasonable
agreement with theoretical calculations within the uncertainties.


title:
Oil-in-water microfluidics on the colloidal scale: new routes to
  self-assembly and glassy packings

abstract:
  We have developed Norland Optical Adhesive (NOA) flow focusing devices,
making use of the excellent solvent compatibility and surface properties of NOA
to generate micron scale oil-in-water emulsions with polydispersities as low as
5%. While current work on microfluidic oil-in-water emulsification largely
concerns the production of droplets with sizes on the order of 10s of
micrometres, large enough that Brownian motion is negligible, our NOA devices
can produce droplets with radii ranging from 2 {\mu}m to 12 {\mu}m. To
demonstrate the utility of these emulsions as colloidal model systems we
produce fluorescently labelled polydimethylsiloxane droplets suitable for
particle resolved studies with confocal microscopy. We analyse the structure of
the resulting emulsion in 3D using coordinate tracking and the topological
cluster classification and reveal a new mono-disperse thermal system.


title:
Compatible and Usable Mandatory Access Control for Good-enough OS
  Security

abstract:
  OS compromise is one of the most serious computer security problems today,
but still not being resolved. Although people proposed different kinds of
methods, they could not be accepted by most users who are non-expert due to the
lack of compatibility and usability. In this paper, we introduce a kind of new
mandatory access control model, named CUMAC, that aims to achieve good-enough
security, high compatibility and usability. It has two novel features. One is
access control based on tracing potential intrusion that can reduce false
negatives and facilitate security configuration, in order to improve both
compatibility and usability; the other is automatically figuring out all of the
compatibility exceptions that usually incurs incompatible problems. The
experiments performed on the prototype show that CUMAC can defense attacks from
network, mobile disk and local untrustable users while keeping good
compatibility and usability.


title: Statistical Dynamics of Regional Populations and Economies

abstract:
  A practical statistical analysis on the regional populations and GDPs of
China is conducted. The result shows that the distribution of the populations
and that of the GDPs obeys the shifted power law, respectively. To understand
these characteristics, a generalized Langevin equation describing variation of
population is proposed based on the correlation between population and GDP as
well as the random fluctuations of the related factors. The equation is
transformed into the Fokker-Plank equation, and the solution demonstrates a
transform of population distribution from the normal Gaussian distribution to a
shifted power law. It also suggests a critical point of time at which the
transform occurs. The shifted power law distribution in the supercritical
situation is qualitatively in accordance with the practical result. The
distribution of the GDPs is derived based on the Cobb-Douglas production
function, and presents a change from a shifted power law to the Gaussian
distribution. This result indicates that the regional GDP distribution of our
society will be the Gaussian distribution in the future. The analysis on the
growth trend of economy suggests it will become a reality. These theoretical
attempts may draw a historical picture of our world in the aspects of
population and economy.


title: Effective field theory approach to many-body localization

abstract:
  We construct an analytic theory of many-body localization (MBL) in random
spin chains. The approach is based on a first quantized perspective in which
MBL is understood as a localization phenomenon on the high dimensional lattice
defined by the discrete Hilbert space of the clean system. We construct a field
theory on that lattice and apply it to discuss the stability of a weak disorder
(`Wigner-Dyson') and a strong disorder (`Poisson') phase.


title:
A Probabilistic Optimum-Path Forest Classifier for Binary Classification
  Problems

abstract:
  Probabilistic-driven classification techniques extend the role of traditional
approaches that output labels (usually integer numbers) only. Such techniques
are more fruitful when dealing with problems where one is not interested in
recognition/identification only, but also into monitoring the behavior of
consumers and/or machines, for instance. Therefore, by means of probability
estimates, one can take decisions to work better in a number of scenarios. In
this paper, we propose a probabilistic-based Optimum Path Forest (OPF)
classifier to handle with binary classification problems, and we show it can be
more accurate than naive OPF in a number of datasets. In addition to being just
more accurate or not, probabilistic OPF turns to be another useful tool to the
scientific community.


title:
Conformal blocks on a 2-sphere with indistinguishable punctures and
  implications on black hole entropy

abstract:
  The dimensionality of the Hilbert space of a Chern-Simons theory on a 3-fold,
in the presence of Wilson lines carrying spin representations, had been counted
by using its link with the Wess-Zumino theory, with level $k$, on the 2-sphere
with points (to be called punctures) marked by the piercing of the
corresponding Wilson lines and carrying the respective spin representations. It
is shown, in the weak coupling (large $k$) limit, the formula decouples into
two characteristically distinct parts; one mimics the dimensionality of the
Hilbert space of a collection of non-interacting spin systems and the other is
an effective overall correction contributed by all the punctures. The exact
formula yield from this counting has been shown earlier to have resulted from
the consideration of the punctures to be distinguishable. We investigate the
same counting problem by considering the punctures to be indistinguishable.
Although the full formula remains undiscovered, nonetheless, we are able to
impose the relevant statistics for indistinguishable punctures in the
approximate formula resulting from the weak coupling limit. As an implication
of this counting, in the context of its relation to that of black hole entropy
calculation in quantum geometric approach, we are able to show that the
logarithmic area correction, with a coefficient of $-3/2$, that results in this
method of entropy calculation, in independent of whether the punctures are
distinguishable or not.


title:
Valley splitting in the transition-metal dichalcogenides monolayer via
  atoms adsorption

abstract:
  In this letter we study the valley degeneracy splitting of the
transition-metal dichalcogenides monolayer by first-principles calculations.
The local magnetic moments are introduced into the system when the
transition-metal atoms are adsorbed to the monolayer surface. Zeeman effect
arising from the local magnetic moment at transition-metal atom sites lifts the
valley degeneracy. Anomalous charge, spin and valley Hall Effects can be
accessed due to valley splitting when we can only excite carriers of one
valley. The valley splitting depends on the direction of magnetization and thus
can be tuned continuously by an external magnetic field. This tunable valley
splitting offers a practical avenue for exploring device paradigms based on the
spin and valley degrees of freedom.


title: CryptoImg: Privacy Preserving Processing Over Encrypted Images

abstract:
  Cloud computing services provide a scalable solution for the storage and
processing of images and multimedia files. However, concerns about privacy
risks prevent users from sharing their personal images with third-party
services. In this paper, we describe the design and implementation of
CryptoImg, an open source library (Source at
https://github.com/TarekIbnZiad/CryptoImg) of modular privacy preserving image
processing operations over encrypted images. By using homomorphic encryption,
CryptoImg allows the users to delegate their image processing operations to
remote servers without any privacy concerns. Currently, CryptoImg supports a
subset of the most frequently used image processing operations such as image
adjustment, spatial filtering, edge sharpening, histogram equalization and
others. We implemented our library as an extension to the popular computer
vision library OpenCV. CryptoImg can be used from either mobile or desktop
clients. Our experimental results demonstrate that CryptoImg is efficient while
performing operations over encrypted images with negligible error and
reasonable time overheads on the supported platforms


title: $q$-Difference Kac-Schwarz Operators in Topological String Theory

abstract:
  The perspective of Kac-Schwarz operators is introduced to the authors'
previous work on the quantum mirror curves of topological string theory in
strip geometry and closed topological vertex. Open string amplitudes on each
leg of the web diagram of such geometry can be packed into a multi-variate
generating function. This generating function turns out to be a tau function of
the KP hierarchy. The tau function has a fermionic expression, from which one
finds a vector $|W\rangle$ in the fermionic Fock space that represents a point
$W$ of the Sato Grassmannian. $|W\rangle$ is generated from the vacuum vector
$|0\rangle$ by an operator $g$ on the Fock space. $g$ determines an operator
$G$ on the space $V = \mathbb{C}((x))$ of Laurent series in which $W$ is
realized as a linear subspace. $G$ generates an admissible basis
$\{\Phi_j(x)\}_{j=0}^\infty$ of $W$. $q$-difference analogues $A$, $B$ of
Kac-Schwarz operators are defined with the aid of $G$. $\Phi_j(x)$'s satisfy
the linear equations $A\Phi_j(x) = q^j\Phi_j(x)$, $B\Phi_j(x) = \Phi_{j+1}(x)$.
The lowest equation $A\Phi_0(x) = \Phi_0(x)$ reproduces the quantum mirror
curve in the authors' previous work.


title: Detecting Rare and Weak Spikes in Large Covariance Matrices

abstract:
  Given $p$-dimensional Gaussian vectors $X_i \stackrel{iid}{\sim} N(0,
\Sigma)$, $1 \leq i \leq n$, where $p \geq n$, we are interested in testing a
null hypothesis where $\Sigma = I_p$ against an alternative hypothesis where
all eigenvalues of $\Sigma$ are $1$, except for $r$ of them are larger than $1$
(i.e., spiked eigenvalues).
  We consider a Rare/Weak setting where the spikes are sparse (i.e., $1 \ll r
\ll p$) and individually weak (i.e., each spiked eigenvalue is only slightly
larger than $1$), and discover a phase transition: the two-dimensional phase
space that calibrates the spike sparsity and strengths partitions into the
Region of Impossibility and the Region of Possibility. In Region of
Impossibility, all tests are (asymptotically) powerless in separating the
alternative from the null. In Region of Possibility, there are tests that have
(asymptotically) full power.
  We consider a CuSum test, a trace-based test, an eigenvalue-based Higher
Criticism test, and a Tracy-Widom test (Johnstone 2001), and show that the
first two tests have asymptotically full power in Region of Possibility.
  To use our results from a different angle, we derive new bounds for (a)
empirical eigenvalues, and (b) cumulative sums of the empirical eigenvalues,
both under the alternative hypothesis. Part (a) is related to those in Baik,
Ben-Arous and Peche (2005), but both the settings and results are different.
  The study requires careful analysis of the $L^1$-distance of our testing
problem and delicate Radom Matrix Theory. Our technical devises include (a) a
Gaussian proxy model, (b) Le Cam's comparison of experiments, and (c) large
deviation bounds on empirical eigenvalues.


title: Boundary Conditions of Weyl Semimetals

abstract:
  We find that generic boundary conditions of Weyl semimetal is dictated by
only a single real parameter, in the continuum limit. We determine how the
energy dispersions (the Fermi arcs) and the wave functions of edge states
depend on this parameter. Lattice models are found to be consistent with our
generic observation. Furthermore, the enhanced parameter space of the boundary
condition is shown to support a novel topological number.


title:
Harnack Inequalities for SDEs Driven by Time-Changed Fractional Brownian
  Motions

abstract:
  We establish Harnack inequalities for stochastic differential equations
(SDEs) driven by a time-changed fractional Brownian motion with Hurst parameter
$H\in(0,1/2)$. The Harnack inequality is dimension-free if the SDE has a drift
which satisfies a one-sided Lipschitz condition, otherwise we still get
Harnack-type estimates, but the constants will, in general, depend on the space
dimension. Our proof is based on a coupling argument and a regularization
argument for the time-change.


title: Slip Morphology of Elastic Strips on Frictional Rigid Substrates

abstract:
  The morphology of an elastic strip subject to vertical compressive stress on
a frictional rigid substrate is investigated by a combination of theory and
experiment. We find a rich variety of morphologies, which -when the bending
elasticity dominates over the effect of gravity- are classified into three
distinct types of states: pinned, partially slipped, and completely slipped,
depending on the magnitude of the vertical strain and coefficient of static
friction. We develop a theory of elastica under mixed clamped-hinged boundary
conditions combined with the Coulomb-Amontons friction law, and find excellent
quantitative agreement with simulations and controlled physical experiments. We
also discuss the effect of gravity in order to bridge the difference in
qualitative behaviors of stiff strips and flexible strings, or ropes. Our study
thus complements recent work on elastic rope coiling, and takes a significant
step towards establishing a unified understanding of how a thin elastic object
interacts vertically with a solid surface.


title:
Attack Allocation on Remote State Estimation in Multi-Systems:
  Structural Results and Asymptotic Solution

abstract:
  This paper considers optimal attack attention allocation on remote state
estimation in multi-systems. Suppose there are $\mathtt{M}$ independent
systems, each of which has a remote sensor monitoring the system and sending
its local estimates to a fusion center over a packet-dropping channel. An
attacker may generate noises to exacerbate the communication channels between
sensors and the fusion center. Due to capacity limitation, at each time the
attacker can exacerbate at most $\mathtt{N}$ of the $\mathtt{M}$ channels. The
goal of the attacker side is to seek an optimal policy maximizing the
estimation error at the fusion center. The problem is formulated as a Markov
decision process (MDP) problem, and the existence of an optimal deterministic
and stationary policy is proved. We further show that the optimal policy has a
threshold structure, by which the computational complexity is reduced
significantly. Based on the threshold structure, a myopic policy is proposed
for homogeneous models and its optimality is established. To overcome the curse
of dimensionality of MDP algorithms for general heterogeneous models, we
further provide an asymptotically (as $\mathtt{M}$ and $\mathtt{N}$ go to
infinity) optimal solution, which is easy to compute and implement. Numerical
examples are given to illustrate the main results.


title:
Effects of sapphire nitridation and growth temperature on the epitaxial
  growth of hexagonal boron nitride on sapphire

abstract:
  This paper reports on the epitaxial growth of hexagonal boron nitride (hBN)
films on sapphire substrates in a cold wall chemical vapor deposition (CVD)
system where different sapphire nitridation and hBN growth temperatures were
employed. A thin and amorphous nitridated layer was formed at a low temperature
(850 C), which enabled subsequent epitaxial hBN growth at 1350 C. The
influences of the sapphire nitridation temperature and the growth temperature
on the film quality were analyzed by X-ray diffraction (XRD) measurements.
Higher than optimum nitridation and growth temperatures improve the crystalline
quality of the nitridated layer, but does not favor the epitaxial growth of
hBN. hBN films grown at the optimum conditions exhibit the c-lattice constant
of 6.66 {\AA} from the XRD {\theta}-2{\theta} scan, and the characteristic in
plane stretching vibration at 1370.5/cm from Raman spectroscopy. X-ray
photoelectron spectroscopy analysis confirmed the formation of stoichiometric
hBN films with excellent uniformity.


title:
Distributed Power Control for Delay Optimization in Energy Harvesting
  Cooperative Relay Networks

abstract:
  We consider cooperative communications with energy harvesting (EH) relays,
and develop a distributed power control mechanism for the relaying terminals.
Unlike prior art which mainly deal with single-relay systems with saturated
traffic flow, we address the case of bursty data arrival at the source
cooperatively forwarded by multiple half-duplex EH relays. We aim at optimizing
the long-run average delay of the source packets under the energy neutrality
constraint on power consumption of each relay. While EH relay systems have been
predominantly optimized using either offline or online methodologies, we take
on a more realistic learning-theoretic approach. Hence, our scheme can be
deployed for real-time operation without assuming acausal information on
channel realizations, data/energy arrivals as required by offline optimization,
nor does it rely on precise statistics of the system processes as is the case
with online optimization. We formulate the problem as a partially observable
identical payoff stochastic game (PO-IPSG) with factored controllers, in which
the power control policy of each relay is adaptive to its local
source-to-relay/relay-to-destination channel states, its local energy state as
well as to the source buffer state information. We derive a multi-agent
reinforcement learning algorithm which is convergent to a locally optimal
solution of the formulated PO-IPSG. The proposed algorithm operates without
explicit message exchange between the relays, while inducing only little
source-relay signaling overhead. By simulation, we contrast the delay
performance of the proposed method against existing heuristics for throughput
maximization. It is shown that compared with these heuristics, the systematic
approach adopted in this paper has a smaller sub-optimality gap once evaluated
against a centralized optimal policy armed with perfect statistics.


title:
Hypercomplex Signal Energy Concentration in the Spatial and Quaternionic
  Linear Canonical Frequency Domains

abstract:
  Quaternionic Linear Canonical Transforms (QLCTs) are a family of integral
transforms, which generalized the quaternionic Fourier transform and
quaternionic fractional Fourier transform. In this paper, we extend the energy
concentration problem for 2D hypercomplex signals (especially quaternionic
signals). The most energy concentrated signals both in 2D spatial and
quaternionic linear canonical frequency domains simultaneously are recently
recognized to be the quaternionic prolate spheroidal wave functions (QPSWFs).
The improved definitions of QPSWFs are studied which gave reasonable
properties. The purpose of this paper is to understand the measurements of
energy concentration in the 2D spatial and quaternionic linear canonical
frequency domains. Examples of energy concentrated ratios between the truncated
Gaussian function and QPSWFs intuitively illustrate that QPSWFs are more energy
concentrated signals.


title:
Prolate Spheroidal Wave Functions Associated with the Quaternionic
  Fourier Transform

abstract:
  One of the fundamental problems in communications is finding the energy
distribution of signals in time and frequency domains. It should, therefore, be
of great interest to find the most energy concentration hypercomplex signal.
The present paper finds a new kind of hypercomplex signals whose energy
concentration is maximal in both time and frequency under quaternionic Fourier
transform. The new signals are a generalization of the prolate spheroidal wave
functions (also known as Slepian functions) to quaternionic space, which are
called quaternionic prolate spheroidal wave functions. The purpose of this
paper is to present the definition and properties of the quaternionic prolate
spheroidal wave functions and to show that they can reach the extreme case in
energy concentration problem both from the theoretical and experimental
description. In particular, these functions are shown as an effective method
for bandlimited signals extrapolation problem.


title:
Rotational equilibria by Lagrangian variational principle: toward
  multi-dimensional stellar evolutions

abstract:
  We have developed a new formulation to obtain self-gravitating, axisymmetric
configurations in permanent rotation. The formulation is based on the
Lagrangian variational principle with a triangulated mesh. It treats not only
barotropic but also baroclinic equations of state. We compare the various
stellar equilibria obtained by our new scheme with those by Hachisu's
self-consistent field scheme for the barotropic case, and those by Fujisawa's
self-consistent field scheme for the baroclinic case. Included in these
rotational configurations are those with shellular-type rotations, which are
commonly assumed in the evolution calculation of rotating stars. Although
radiation processes, convections and meridional flows have not been taken into
account in this study, we have in mind the application of this method to the
two-dimensional evolution calculations of rotating stars, for which the
Lagrangian formulation is best suited.


title:
Low-Rank Tensor Networks for Dimensionality Reduction and Large-Scale
  Optimization Problems: Perspectives and Challenges PART 1

abstract:
  Machine learning and data mining algorithms are becoming increasingly
important in analyzing large volume, multi-relational and multi--modal
datasets, which are often conveniently represented as multiway arrays or
tensors. It is therefore timely and valuable for the multidisciplinary research
community to review tensor decompositions and tensor networks as emerging tools
for large-scale data analysis and data mining. We provide the mathematical and
graphical representations and interpretation of tensor networks, with the main
focus on the Tucker and Tensor Train (TT) decompositions and their extensions
or generalizations.
  Keywords: Tensor networks, Function-related tensors, CP decomposition, Tucker
models, tensor train (TT) decompositions, matrix product states (MPS), matrix
product operators (MPO), basic tensor operations, multiway component analysis,
multilinear blind source separation, tensor completion, linear/multilinear
dimensionality reduction, large-scale optimization problems, symmetric
eigenvalue decomposition (EVD), PCA/SVD, huge systems of linear equations,
pseudo-inverse of very large matrices, Lasso and Canonical Correlation Analysis
(CCA) (This is Part 1)


title: Stellar populations in star clusters

abstract:
  Stellar populations contain the most important information about star clus-
ter formation and evolution. Until several decades ago, star clusters were
believed to be ideal laboratories for studies of simple stellar populations
(SSPs). However, discoveries of multiple stellar populations in Galactic
globular clusters have expanded our view on stellar populations in star
clusters. They have simultaneously generated a number of controversies,
particularly as to whether young star clusters may have the same origin as old
globular clusters. In addition, extensive studies have revealed that the SSP
scenario does not seem to hold for some intermediate-age and young star
clusters either, thus making the origin of multiple stellar populations in star
clusters even more complicated. Stellar population anomalies in numerous star
clusters are well-documented, implying that the notion of star clusters as true
SSPs faces serious challenges. In this review, we focus on stellar populations
in massive clusters with different ages. We present the history and progress of
research in this active field, as well as some of the most recent improvements,
including observational results and scenar- ios that have been proposed to
explain the observations. Although our current ability to determine the origin
of multiple stellar populations in star clusters is unsatisfactory, we propose
a number of promising projects that may contribute to a significantly improved
understanding of this subject.


title:
Theoretical study of the Xi(1620) and Xi(1690) resonances in Xi_c ->
  pi^+ MB decays

abstract:
  Nonleptonic weak decays of Xi_c into pi^+ and a meson (M)-baryon (B) final
state, MB, are analyzed from the viewpoint of probing S=-2 baryon resonances,
i.e. Xi(1620) and Xi(1690), of which spin-parity and other properties are not
well known. We argue that the weak decay of Xi_c is dominated by a single
quark-line diagram, preferred by the Cabibbo-Kobayashi-Maskawa coefficient,
color recombination factor, the diquark correlation, and the kinematical
condition. The decay process has an advantage of being free from meson
resonances in the pi^+M invariant mass distribution. The invariant mass
distribution of the meson-baryon final state is calculated with three different
chiral unitary approaches, assuming that the Xi(1620) and Xi(1690) resonances
have J^P=1/2^-. It is found that a clear peak for the Xi(1690) is seen in the
piXi and KbarLambda spectra. We also suggest that the ratios of the piXi,
KbarLambda and KbarSigma final states are useful to distinguish whether the
peak is originated from the Xi(1690) resonance or it is a KbarSigma threshold
effect.


title: A Robust Sparse Fourier Transform in the Continuous Setting

abstract:
  In recent years, a number of works have studied methods for computing the
Fourier transform in sublinear time if the output is sparse. Most of these have
focused on the discrete setting, even though in many applications the input
signal is continuous and naive discretization significantly worsens the
sparsity level.
  We present an algorithm for robustly computing sparse Fourier transforms in
the continuous setting. Let $x(t) = x^*(t) + g(t)$, where $x^*$ has a
$k$-sparse Fourier transform and $g$ is an arbitrary noise term. Given sample
access to $x(t)$ for some duration $T$, we show how to find a
$k$-Fourier-sparse reconstruction $x'(t)$ with
  $$\frac{1}{T}\int_0^T |x'(t) - x(t) |^2 \mathrm{d} t \lesssim
\frac{1}{T}\int_0^T | g(t)|^2 \mathrm{d}t.$$
  The sample complexity is linear in $k$ and logarithmic in the signal-to-noise
ratio and the frequency resolution. Previous results with similar sample
complexities could not tolerate an infinitesimal amount of i.i.d. Gaussian
noise, and even algorithms with higher sample complexities increased the noise
by a polynomial factor. We also give new results for how precisely the
individual frequencies of $x^*$ can be recovered.


title: On the Calabi-Yau equation in the Kodaira-Thurston manifold

abstract:
  We review some previous results about the Calabi-Yau equation on the
Kodaira-Thurston manifold equipped with an invariant almost-Kaehler structure
and assuming the volume form invariant by the action of a torus. In particular,
we observe that under some restrictions the problem is reduced to a
Monge-Amp\`ere equation by using the ansatz $\tilde \omega=\Omega-dJdu+da$,
where $u$ is a $T^2$-invariant function and $a$ is a $1$-form depending on $u$.
Furthermore, we extend our analysis to non-invariant almost-complex structures
by considering some basic cases and we finally take into account a
generalization to higher dimensions.


title: Planetary systems in star clusters

abstract:
  Thousands of confirmed and candidate exoplanets have been identified in
recent years. Consequently, theoretical research on the formation and dynamical
evolution of planetary systems has seen a boost, and the processes of
planet-planet scattering, secular evolution, and interaction between planets
and gas/debris disks have been well-studied. Almost all of this work has
focused on the formation and evolution of isolated planetary systems, and
neglect the effect of external influences, such as the gravitational
interaction with neighbouring stars. Most stars, however, form in clustered
environments that either quickly disperse, or evolve into open clusters. Under
these conditions, young planetary systems experience frequent close encounters
with other stars, at least during the first 1-10 Myr, which affects planets
orbiting at any period range, as well as their debris structures.


title:
First Monte Carlo analysis of fragmentation functions from
  single-inclusive $e^+ e^-$ annihilation

abstract:
  We perform the first iterative Monte Carlo (IMC) analysis of fragmentation
functions constrained by all available data from single-inclusive $e^+ e^-$
annihilation into pions and kaons. The IMC method eliminates potential bias in
traditional analyses based on single fits introduced by fixing parameters not
well contrained by the data and provides a statistically rigorous determination
of uncertainties. Our analysis reveals specific features of fragmentation
functions using the new IMC methodology and those obtained from previous
analyses, especially for light quarks and for strange quark fragmentation to
kaons.


title:
Joint Statistics of Strongly Correlated Neurons via Dimensional
  Reduction

abstract:
  The relative timing of action potentials in neurons recorded from local
cortical networks often shows a non-trivial dependence, which is then
quantified by cross-correlation functions. Theoretical models emphasize that
such spike train correlations are an inevitable consequence of two neurons
being part of the same network and sharing some synaptic input. For non-linear
neuron models, however, explicit correlation functions are difficult to compute
analytically, and perturbative methods work only for weak shared input. In
order to treat strong correlations, we suggest here an alternative
non-perturbative method. Specifically, we study the case of two leaky
integrate-and-fire neurons with strong shared input. Correlation functions
derived from simulated spike trains fit our theoretical predictions very
accurately. Using our method, we computed the non-linear correlation transfer
as well as correlation functions that are asymmetric due to inhomogeneous
intrinsic parameters or unequal input.


title: Iron K$\alpha$ line of boson stars

abstract:
  The present paper is a sequel to our previous work [Y. Ni et al., JCAP 1607,
049 (2016)] in which we studied the iron K$\alpha$ line expected in the
reflection spectrum of Kerr black holes with scalar hair. These metrics are
solutions of Einstein's gravity minimally coupled to a massive, complex scalar
field. They form a continuous bridge between a subset of Kerr black holes and a
family of rotating boson stars depending on one extra parameter, the
dimensionless scalar hair parameter $q$, ranging from 0 (Kerr black holes) to 1
(boson stars). Here we study the limiting case $q=1$, corresponding to rotating
boson stars. For comparison, spherical boson stars are also considered. We
simulate observations with XIS/Suzaku. Using the fact that current observations
are well fit by the Kerr solution and thus requiring that acceptable
alternative compact objects must be compatible with a Kerr fit, we find that
some boson star solutions are relatively easy to rule out as potential
candidates to explain astrophysical black holes, while other solutions, which
are neither too dilute nor too compact are more elusive and we argue that they
cannot be distinguished from Kerr black holes by the analysis of the iron line
with current X-ray facilities.


title: The Damascus Inequality

abstract:
  In 2016 Prof. Fozi M. Dannan from Damascus, Syria proposed an inequality for
three positive numbers with unit product. It became widely known but was not
proved yet in spite of elementary formulation. We give some proofs for this
inequality, a number of its generalizations and some connected unsolved
problems and conjectures.


title:
Generating coherent soft x-ray pulses in the water window with a
  high-brightness seeded free-electron laser

abstract:
  We propose a new scheme to generate high-brightness and temporal coherent
soft x-ray radiation in a seeded free-electron laser. The proposed scheme is
based the coherent harmonic generation (CHG) and superradiant principles. A CHG
scheme is first used to generate coherent signal at ultra-high harmonics of the
seed. This coherent signal is then amplified by a series of chicane-undulator
modules via the fresh bunch and superradiant processes in the following
radiator. Using a representative of realistic set of parameters,
three-dimensional simulations have been carried out and the simulations results
demonstrated that 10 GW-level ultra-short coherent radiation pulses in the
water window can be achieved by using the proposed technique.


title: High Dimensional Human Guided Machine Learning

abstract:
  Have you ever looked at a machine learning classification model and thought,
I could have made that? Well, that is what we test in this project, comparing
XGBoost trained on human engineered features to training directly on data. The
human engineered features do not outperform XGBoost trained di- rectly on the
data, but they are comparable. This project con- tributes a novel method for
utilizing human created classifi- cation models on high dimensional datasets.


title: Dihedral Galois covers of algebraic varieties and the simple cases

abstract:
  In this article we investigate the algebra and geometry of dihedral covers of
smooth algebraic varieties. To this aim we first describe the Weil divisors and
the Picard group of divisorial sheaves on normal double covers. Then we provide
a structure theorem for dihedral covers, that is, given a smooth variety Y, we
describe the algebraic "building data" on Y which are equivalent to the
existence of such covers X --> Y. We introduce then two special very explicit
classes of dihedral covers: the simple and the almost simple dihedral covers,
and we determine their basic invariants. For the simple dihedral covers we also
determine their natural deformations. In the last section we give an
application to fundamental groups.


title: Nonlinear regimes in mean-field full-sphere dynamo

abstract:
  The mean-field dynamo model is employed to study the non-linear dynamo
regimes in a fully convective star of mass 0.3$M_{\odot}$ rotating with period
of 10 days. For the intermediate value of the parameter of the turbulent
magnetic Prandl number, $Pm_{T}=3$ we found the oscillating dynamo regimes with
period about 40Yr. The higher $Pm_{T}$ results to longer dynamo periods. If the
large-scale flows is fixed we find that the dynamo transits from axisymmetric
to non-axisymmetric regimes for the overcritical parameter of the
$\alpha$effect. The change of dynamo regime occurs because of the
non-axisymmetric non-linear $\alpha$-effect. The situation persists in the
fully non-linear dynamo models with regards of the magnetic feedback on the
angular momentum balance and the heat transport in the star. It is found that
the large-scale magnetic field quenches the latitudinal shear in the bulk of
the star. However, the strong radial shear operates in the subsurface layer of
the star. In the nonlinear case the profile of the angular velocity inside the
star become close to the spherical surfaces. This supports the equator-ward
migration of the axisymmetric magnetic field dynamo waves. It was found that,
the magnetic configuration of the star dominates by the regular
non-axisymmetric mode m=1, forming Yin Yang magnetic polarity pattern with the
strong (>500 G) poloidal magnetic field in polar regions.


title:
Gravitational Waves from Primordial Black Holes and New Weak Scale
  Phenomena

abstract:
  We entertain the possibility that primordialblack holes of mass $\sim
(10^{26}$--$10^{29})$~g, with Schwarzschild radii of $\mathcal{O}{\text{cm}}$,
constitute $\sim 10\%$ or more of cosmic dark matter, as allowed by various
constraints. These black holes would typically originate from cosmological eras
corresponding to temperatures $\mathcal{O}{10-100}$~GeV, and may be associated
with first order phase transitions in the visible or hidden sectors. In case
these small primordial black holes get captured in orbits around neutron stars
or astrophysical black holes in our galactic neighborhood, gravitational waves
from the resulting "David and Goliath (D\&G)" binaries could be detectable at
Advanced LIGO or Advanced Virgo for hours or more, possibly over distances of
$\mathcal{O}{10}$~Mpc encompassing the Local Supercluster of galaxies. The
proposed Einstein Telescope would further expand the reach for these signals. A
positive signal could be further corroborated by the discovery of new particles
in the $\mathcal{O}{10-100}$~GeV mass range, and potentially also the detection
of long wavelength gravitational waves originating from the first order phase
transition era.


title: Some recent developments in statistics for spatial point patterns

abstract:
  This paper reviews developments in statistics for spatial point processes
obtained within roughly the last decade. These developments include new classes
of spatial point process models such as determinantal point processes, models
incorporating both regularity and aggregation, and models where points are
randomly distributed around latent geometric structures. Regarding parametric
inference the main focus is on various types of estimating functions derived
from so-called innovation measures. Optimality of such estimating functions is
discussed as well as computational issues. Maximum likelihood inference for
determinantal point processes and Bayesian inference are briefly considered
too. Concerning non-parametric inference, we consider extensions of functional
summary statistics to the case of inhomogeneous point processes as well as new
approaches to simulation based inference.


title: The growth constant of odd cutsets in high dimensions

abstract:
  A cutset is a non-empty finite subset of $\mathbb{Z}^d$ which is both
connected and co-connected. A cutset is odd if its vertex boundary lies in the
odd bipartition class of $\mathbb{Z}^d$. Peled suggested that the number of odd
cutsets which contain the origin and have $n$ boundary edges may be of order
$e^{\Theta(n/d)}$ as $d \to \infty$, much smaller than the number of general
cutsets, which was shown by Lebowitz and Mazel to be of order
$d^{\Theta(n/d)}$. In this paper, we verify this by showing that the number of
such odd cutsets is $(2+o(1))^{n/2d}$.


title: Endomorphisms of projective bundles over a certain class of varieties

abstract:
  Let $B$ be a simply-connected projective variety such that the first
cohomology groups of all line bundles on $B$ are zero. Let $E$ be a vector
bundle over $B$ and $X={\mathbb P} (E)$. It is easily seen that a power of any
endomorphism of $X$ takes fibers to fibers. We prove that if $X$ admits an
endomorphism which is of degree greater than one on the fibers then $E$ splits
into a direct sum of line bundles.


title:
Downward relativistic potential step and phenomenological account of
  Bohmian trajectories of the Klein paradox

abstract:
  The Dirac equation has been applied to fermions scattering from the downward
potential step. The results show some particles do not fall off the edge of the
step and reflect. Also, based on de Broglie-Bohm interpretation of quantum
mechanics (Bohmian mechanics) and Bohmian trajectories we have resolved the
problem. Lastly, a phenomenological study of the Bohmian trajectory of the
Klein paradox has been discussed.