title: FCNC decays of SM fermions into a dark photon

abstract:
  We analyze a new class of FCNC processes, the $f \to f^{\prime} \,
\bar{\gamma}$ decays of a fermion $f$ into a lighter (same-charge) fermion
$f^{\prime}$ plus a {\it massless} neutral vector boson, a {\it dark photon}
$\bar{\gamma}$. A massless dark photon does not interact at tree level with
observable fields, and the $f \!\to\! f^{\prime} \, \bar{\gamma}$ decay
presents a characteristic signature where the final fermion $f^{\prime}$ is
balanced by a {\it massless invisible} system. Models recently proposed to
explain the exponential spread in the standard-model Yukawa couplings can
indeed foresee an extra unbroken {\it dark} $U(1)$ gauge group, and the
possibility to couple on-shell dark photons to standard-model fermions via
one-loop magnetic-dipole kind of FCNC interactions. The latter are suppressed
by the characteristic scale related to the mass of heavy messengers, connecting
the standard model particles to the dark sector. We compute the corresponding
decay rates for the top, bottom, and charm decays ($t\to c\, \bar{\gamma},u\,
\bar{\gamma}$, $\;b\to s\, \bar{\gamma},d\, \bar{\gamma}$, and $c\to u
\bar{\gamma}$), and for the charged-lepton decays ($\tau \to \mu\,
\bar{\gamma}, e\, \bar{\gamma}$, and $\mu \to e \bar{\gamma}$) in terms of
model parameters. We find that large branching ratios for both quark and lepton
decays are allowed in case the messenger masses are in the discovery range of
the LHC. Implications of these new decay channels at present and future
collider experiments are briefly discussed.


title:
High order algorithm for the time-tempered fractional Feynman-Kac
  equation

abstract:
  We provide and analyze the high order algorithms for the model describing the
functional distributions of particles performing anomalous motion with
power-law jump length and tempered power-law waiting time. The model is derived
in [Wu, Deng, and Barkai, Phys. Rev. E., 84 (2016), 032151], being called the
time-tempered fractional Feynman-Kac equation. The key step of designing the
algorithms is to discretize the time tempered fractional substantial
derivative, being defined as $${^S\!}D_t^{\gamma,\widetilde{\lambda}}
G(x,p,t)\!=\!D_t^{\gamma,\widetilde{\lambda}} G(x,p,t)\!-\!\lambda^\gamma
G(x,p,t) ~{\rm with}~\widetilde{\lambda}=\lambda+ pU(x),\, p=\rho+J\eta,\,
J=\sqrt{-1},$$ where $$D_t^{\gamma,\widetilde{\lambda}} G(x,p,t)
=\frac{1}{\Gamma(1-\gamma)} \left[\frac{\partial}{\partial
t}+\widetilde{\lambda} \right]
\int_{0}^t{\left(t-z\right)^{-\gamma}}e^{-\widetilde{\lambda}\cdot(t-z)}{G(x,p,z)}dz,$$
and $\lambda \ge 0$, $0<\gamma<1$, $\rho>0$, and $\eta$ is a real number. The
designed schemes are unconditionally stable and have the global truncation
error $\mathcal{O}(\tau^2+h^2)$, being theoretically proved and numerically
verified in {\em complex} space. Moreover, some simulations for the
distributions of the first passage time are performed, and the second order
convergence is also obtained for solving the `physical' equation (without
artificial source term).


title: Distance proper connection of graphs and their complements

abstract:
  Let $G$ be an edge-colored connected graph. A path $P$ in $G$ is called a
distance $\ell$-proper path if no two edges of the same color can appear with
less than $\ell$ edges in between on $P$. The graph $G$ is called
$(k,\ell)$-proper connected if there is an edge-coloring such that every pair
of distinct vertices of $G$ are connected by $k$ pairwise internally
vertex-disjoint distance $\ell$-proper paths in $G$. The minimum number of
colors needed to make $G$ $(k,\ell)$-proper connected is called the
$(k,\ell)$-proper connection number of $G$ and denoted by $pc_{k,\ell}(G)$. In
this paper we first focus on the $(1,2)$-proper connection number of $G$
depending on some constraints of $\overline G$. Then, we characterize the
graphs of order $n$ with $(1,2)$-proper connection number $n-1$ or $n-2$. Using
this result, we investigate the Nordhaus-Gaddum-Type problem of $(1,2)$-proper
connection number and prove that $pc_{1,2}(G)+pc_{1,2}(\overline{G})\leq n+2$
for connected graphs $G$ and $\overline{G}$. The equality holds if and only if
$G$ or $\overline{G}$ is isomorphic to a double star.


title:
Superconductivity on the verge of electronic topological transition in
  Fe based superconductors

abstract:
  A comprehensive first principles study on the electronic topological
transition in a number of 122 family of Fe based superconductors is presented.
Doping as well as temperature driven Lifshitz transitions are found from first
principles simulations in a variety of Fe based superconductors that are
consistent with experimental findings. In all the studied compounds the
Lifshitz transitions are consistently found to occur at a doping concentration
where superconductivity is highest and magnetism disappears. Systematically,
the Lifshitz transition occurs in the electron Fermi surfaces for hole doping,
whereas in hole Fermi surfaces for electron doping as well as iso-electronic
doping. Temperature driven Lifshitz transition is found to occur in the
iso-electronic Ru-doped BaFe$_2$As$_2$ compounds. Fermi surface areas are found
to carry sensitivity of topological modifications more acutely than the band
structures and can be used as a better experimental probe to identify
electronic topological transition.


title: Coisotropic Hypersurfaces in Grassmannians

abstract:
  To every projective variety $X$, we associate a family of hypersurfaces in
different Grassmannians, called the coisotropic hypersurfaces of $X$. These
include the Chow form and the Hurwitz form of $X$. Gel'fand, Kapranov and
Zelevinsky characterized coisotropic hypersurfaces by a rank one condition on
tangent spaces. We present a new and simplified proof of that result. We show
that the coisotropic hypersurfaces of $X$ equal those of its projectively dual
variety, and that their degrees are the polar degrees of $X$. Coisotropic
hypersurfaces of Segre varieties are defined by hyperdeterminants, and all
hyperdeterminants arise in that manner. We derive new equations for the Cayley
variety which parametrizes all coisotropic hypersurfaces of given degree in a
fixed Grassmannian. We provide a Macaulay2 package for transitioning between
$X$ and its coisotropic hypersurfaces.


title: On the structure of universal differentiability sets

abstract:
  We prove that universal differentiability sets in Euclidean spaces possess
distinctive structural properties. Namely, we show that any universal
differentiability set contains a `kernel' in which the points of
differentiability of each Lipschitz function are dense. We further prove that
no universal differentiability set may be decomposed as a countable union of
relatively closed, non-universal differentiability sets. The sharpness of this
result, with respect to existing decomposibility results of the opposite
nature, is discussed.


title:
Landau quantization and neutron emissions by nuclei in the crust of a
  magnetar

abstract:
  Magnetars are neutron stars endowed with surface magnetic fields of the order
of $10^{14}-10^{15}$~G, and with presumably much stronger fields in their
interior. As a result of Landau quantization of electron motion, the
neutron-drip transition in the crust of a magnetar is shifted to either higher
or lower densities depending on the magnetic field strength. The impact of
nuclear uncertainties is explored considering the recent series of
Brussels-Montreal microscopic nuclear mass models. All these models are based
on the Hartree-Fock-Bogoliubov method with generalized Skyrme functionals. They
differ in their predictions for the symmetry energy coefficient at saturation,
and for the stiffness of the neutron-matter equation of state. For comparison,
we have also considered the very accurate but more phenomenological model of
Duflo and Zuker. Although the equilibrium composition of the crust of a
magnetar and the onset of neutron emission are found to be model dependent, the
quantum oscillations of the threshold density are essentially universal.


title: Strongly magnetized rotating dipole in general relativity

abstract:
  Electromagnetic waves arise in many area of physics. Solutions are difficult
to find in the general case. In this paper, we numerically integrate Maxwell
equations in a 3D spherical polar coordinate system. Straightforward finite
difference methods would lead to a coordinate singularity along the polar axis.
Spectral methods are better suited to deal with such artificial singularities
related to the choice of a coordinate system. When the radiating object is
rotating like for instance a star, special classes of solutions to Maxwell
equations are worthwhile to study such as quasi-stationary regimes. Moreover,
in high-energy astrophysics, strong gravitational and magnetic fields are
present especially around rotating neutron stars. In order to study such
systems, we designed an algorithm to solve the time-dependent Maxwell equations
in spherical polar coordinates including general relativity as well as quantum
electrodynamical corrections to leading order. As a diagnostic, we compute the
spindown luminosity expected from these stars and compare it to the classical
i.e. non relativistic and non quantum mechanical results. It is shown that
quantum electrodynamics leads to an irrelevant change in the spindown
luminosity even for magnetic field around the critical value of
$\numprint{4.4e9}$~\si{\tesla}. Therefore the braking index remains close to
its value for a point dipole in vacuum namely $n=3$. The same conclusion holds
for a general-relativistic quantum electrodynamically corrected force-free
magnetosphere.


title:
Analysis of patch-test consistent atomistic-to-continuum coupling with
  higher-order finite elements

abstract:
  We formulate a patch test consistent atomistic-to-continuum coupling (a/c)
scheme that employs a second-order (potentially higher-order) finite element
method in the material bulk. We prove a sharp error estimate in the
energy-norm, which demonstrates that this scheme is (quasi-)optimal amongst
energy-based sharp-interface a/c schemes that employ the Cauchy--Born continuum
model. Our analysis also shows that employing a higher-order continuum
discretization does not yield qualitative improvements to the rate of
convergence.


title: Zeros and amoebas of partition functions

abstract:
  Singular sectors $\mathcal{Z}_{\mathrm{sing}}$ (loci of zeros) for
real-valued non-positively defined partition functions $\mathcal{Z}$ of $n$
variables are studied. It is shown that $\mathcal{Z}_{\mathrm{sing}}$ have a
stratified structure and each stratum is a set of certain hypersurfaces in
$\mathbb{R}^n$. The concept of statistical amoebas is introduced and their
properties are studied. Relation with algebraic amoebas is discussed. Tropical
limit of statistical amoebas is considered too.


title: Neutrino Flavor Evolution in Binary Neutron Star Merger Remnants

abstract:
  We study the neutrino flavor evolution in the neutrino-driven wind from a
binary neutron star merger remnant consisting of a massive neutron star
surrounded by an accretion disk. With the neutrino emission characteristics and
the hydrodynamical profile of the remnant consistently extracted from a
three-dimensional simulation, we compute the flavor evolution by taking into
account neutrino coherent forward scattering off ordinary matter and neutrinos
themselves. We employ a "single-trajectory" approach to investigate the
dependence of the flavor evolution on the neutrino emission location and angle.
We also show that the flavor conversion in the merger remnant can affect the
(anti-)neutrino absorption rates on free nucleons and may thus impact the
$r$-process nucleosynthesis in the wind. We discuss the sensitivity of such
results on the change of neutrino emission characteristics, also from different
neutron star merger simulations.


title:
The topological susceptibility in the large-N limit of SU(N) Yang-Mills
  theory

abstract:
  We compute the topological susceptibility of the SU(N) Yang-Mills theory in
the large-N limit with a percent level accuracy. This is achieved by measuring
the gradient-flow definition of the susceptibility at three values of the
lattice spacing for N=3,4,5,6. Thanks to this coverage of parameter space, we
can extrapolate the results to the large-N and continuum limits with
confidence. Open boundary conditions are instrumental to make simulations
feasible on the finer lattices at the larger N.


title:
Supercurrents in chiral channels originate from upstream information
  transfer: a theoretical prediction

abstract:
  It has been thought that the long chiral edge channels cannot support any
supercurrent between the superconducting electrodes. We show theoretically that
the supercurrent can be mediated by a non-local interaction that facilitates a
long-distance information transfer in the direction opposite to electron flow.
We compute the supercurrent for several interaction models, including that of
an external circuit.


title: Theory of photoinduced Floquet Weyl semimetal phases

abstract:
  The Weyl semimetal exhibits various interesting physical phenomena because of
the Weyl points, i.e., linear band-crossings. We show by Floquet theory that a
linearly polarized light applied to a band insulator can induce controllable
Weyl points. In a tight-binding model, we classify different types of
photoinduced Weyl points that lead to a rich phase diagram characterized by the
Chern number defined on each momentum slices of the bulk states. Taking account
of the nonequilibrium electron distribution, we calculate and explain the
nonmonotonous anomalous Hall conductivity in terms of the light frequency
controlled shift of Weyl points' position, which also allows us to examine the
conductivity's dependence on the driving electric field.


title:
From non-ergodic eigenvectors to local resolvent statistics and back: a
  random matrix perspective

abstract:
  We study the statistics of the local resolvent and non-ergodic properties of
eigenvectors for a generalised Rosenzweig-Porter $N\times N$ random matrix
model, undergoing two transitions separated by a delocalised non-ergodic phase.
Interpreting the model as the combination of on-site random energies $\{a_i\}$
and a structurally disordered hopping, we found that each eigenstate is
delocalised over $N^{2-\gamma}$ sites close in energy $|a_j-a_i|\leq
N^{1-\gamma}$ in agreement with Kravtsov \emph{et al}, arXiv:1508.01714. Our
other main result, obtained combining a recurrence relation for the resolvent
matrix with insights from Dyson's Brownian motion, is to show that the
properties of the non-ergodic delocalised phase can be probed studying the
statistics of the local resolvent in a non-standard scaling limit.

categories: cond-mat.dis-nn cond-mat.stat-mech math-ph math.MP quant-ph


title:
Constraint on the internal structure of a neutron star from Vela pulsar
  glitches

abstract:
  Pulsars are spinning extremely rapidly with periods as short as about $1.4$
milliseconds and delays of a few milliseconds per year at most, thus providing
the most accurate clocks in the Universe. Nevertheless, sudden spin ups have
been detected in some pulsars like the emblematic Vela pulsar. These abrupt
changes in the pulsar's rotation period have long been thought to be the
manifestation of a neutron superfluid permeating the inner crust of neutron
stars. However, the neutron superfluid has been recently found to be so
strongly coupled to the crust that it does not carry enough angular momentum to
explain the Vela data. We explore the extent to which pulsar-timing
observations can be reconciled with the standard glitch theory considering the
lack of knowledge of the dense-matter equation of state.


title:
The encoding of proprioceptive inputs in the brain: knowns and unknowns
  from a robotic perspective

abstract:
  Somatosensory inputs can be grossly divided into tactile (or cutaneous) and
proprioceptive -- the former conveying information about skin stimulation, the
latter about limb position and movement. The principal proprioceptors are
constituted by muscle spindles, which deliver information about muscle length
and speed. In primates, this information is relayed to the primary
somatosensory cortex and eventually the posterior parietal cortex, where
integrated information about body posture (postural schema) is presumably
available. However, coming from robotics and seeking a biologically motivated
model that could be used in a humanoid robot, we faced a number of
difficulties. First, it is not clear what neurons in the ascending pathway and
primary somatosensory cortex code. To an engineer, joint angles would seem the
most useful variables. However, the lengths of individual muscles have
nonlinear relationships with the angles at joints. Kim et al. (Neuron, 2015)
found different types of proprioceptive neurons in the primary somatosensory
cortex -- sensitive to movement of single or multiple joints or to static
postures. Second, there are indications that the somatotopic arrangement ("the
homunculus") of these brain areas is to a significant extent learned. However,
the mechanisms behind this developmental process are unclear. We will report
first results from modeling of this process using data obtained from body
babbling in the iCub humanoid robot and feeding them into a Self-Organizing Map
(SOM). Our results reveal that the SOM algorithm is only suited to develop
receptive fields of the posture-selective type. Furthermore, the SOM algorithm
has intrinsic difficulties when combined with population code on its input and
in particular with nonlinear tuning curves (sigmoids or Gaussians).


title: Analytical Treatment of Benzene Transmittivity

abstract:
  The renormalization method has been previously used in conjunction with the
Lippman-Schwinger equation to calculate transmission probabilities for benzene
molecules, within the tight-binding approximation. Those results are extended
here by presenting explicit formulas for the transmission probability
functions, which are subsequently analysed for their anti-resonances,
resonances and other maxima and minima.


title:
Living Globe: Tridimensional interactive visualization of world
  demographic data

abstract:
  This paper presents Living Globe, an application for visualization of demo-
graphic data supporting the temporal comparison of data from several countries
represented on a 3D globe. Living Globe allows the visual exploration of the
following demographic data: total population, population density and growth,
crude birth and death rates, life expectancy, net migration and population per-
centage of different age groups. While offering unexperienced users a default
mapping of these data variables into visual variables, Living Globe allows more
advanced users to select the mapping, increasing its flexibility. The main
aspects of the Living Globe model and prototype are described as well as the
evaluation results obtained using heuristic evaluation and usability testing.
Some conclusions and ideas for future work are also presented.


title: Color Homography Color Correction

abstract:
  Homographies -- a mathematical formalism for relating image points across
different camera viewpoints -- are at the foundations of geometric methods in
computer vision and are used in geometric camera calibration, image
registration, and stereo vision and other tasks. In this paper, we show the
surprising result that colors across a change in viewing condition (changing
light color, shading and camera) are also related by a homography. We propose a
new color correction method based on color homography. Experiments demonstrate
that solving the color homography problem leads to more accurate calibration.


title: Cosmological arrow of time in f(R) gravity

abstract:
  The cosmological arrow of time may be linked to the thermodynamic arrow by
second law of thermodynamics. The time asymmetry is also associated with
dissipative fluid as Tolman introduced a viscous fluid to generate an arrow of
time in cyclic cosmology. An arrow of time in cyclic cosmology has been shown
using scalar field.In this work we find out the cosmological arrow of time in
f(R) gravity. Here we use the relation between a new scalar field and $f(R)$.
The dynamics of this new scalar field may emerge the arrow of time.


title:
Main Physical Aspects of the Mathematical Conception of Energy in
  Thermodynamics

abstract:
  We consider the main physical notions and phenomena described by the author
in his mathematical theory of thermodynamics. The new mathematical model yields
the equation of state for a wide class of classical gases consisting of
non-polar molecules provided that the spinodal, the critical isochore and the
second virial coefficient are given. As an example, the spinodal, the critical
isochore and the second virial coefficient are taken from the Van-der-Waals
model. For this specific example, the isotherms constructed on the basis of the
author's model are compared to the Van-der-Waals isotherms, obtained from
completely different considerations.


title:
Molecular dynamics simulation of fabrication of Cu mono-component
  metallic glass by physical vapor deposition on Zr substrate

abstract:
  In this work, the single-component Cu metallic glass was fabricated by the
physical vapor deposition on the Zr (0001) crystal substrate at 100 K using the
classical molecular dynamic simulation. The same deposition process was
performed on the Cu (1 0 0) and Ni (1 0 0) crystal substrate for comparison,
only the Cu crystal deposited layer with the fcc structure can be obtained.
When depositing the Cu atoms on the Zr substrate at 300 K, the crystal
structure was formed, which indicates that except the suitable substrate, low
temperature is also a key factor for the amorphous structure formation. The Cu
liquid quenching from 2000 K to 100 K were also simulated with the cooling rate
1012 K/s to form the Cu glass film in this work. The Cu metallic glass from the
two different processes (physical vapor deposition and rapid thermal quenching
from liquid) revealed the same radial distribution function and X-ray
diffraction pattern, but the different microstructure from the coordination
number and Voronoi tessellation analysis.


title:
Li-Yau gradient bound for collapsing manifolds under integral curvature
  condition

abstract:
  Let $(\M^n, g_{ij})$ be a complete Riemammnian manifold. For some constants
$p,\ r>0$, define $\displaystyle k(p,r)=\sup_{x\in
M}r^2\left(\oint_{B(x,r)}|Ric^-|^p dV\right)^{1/p}$, where $Ric^-$ denotes the
negative part of the Ricci curvature tensor. We prove that for any
$p>\frac{n}{2}$, when $k(p,1)$ is small enough, certain Li-Yau type gradient
bound holds for the positive solutions of the heat equation on geodesic balls
$B(O,r)$ in $\M$ with $0<r\leq 1$. Here the assumption that $k(p,1)$ being
small allows the situation where the manifolds is collapsing. Recall that in
\cite{ZZ}, certain Li-Yau gradient bounds was also obtained by the authors,
assuming that $|Ric^-|\in L^p(\M)$ and the manifold is noncollaped. Therefore,
to some extent, the results in this paper and in \cite{ZZ} complete the picture
of Li-Yau gradient bound for the heat equation on manifolds with $|Ric^-|$
being $L^p$ integrable, modulo sharpness of constants.


title: Data-driven generation of spatio-temporal routines in human mobility

abstract:
  The generation of realistic spatio-temporal trajectories of human mobility is
of fundamental importance in a wide range of applications, such as the
developing of protocols for mobile ad-hoc networks or what-if analysis in urban
ecosystems. Current generative algorithms fail in accurately reproducing the
individuals' recurrent schedules and at the same time in accounting for the
possibility that individuals may break the routine during periods of variable
duration. In this article we present DITRAS (DIary-based TRAjectory Simulator),
a framework to simulate the spatio-temporal patterns of human mobility. DITRAS
operates in two steps: the generation of a mobility diary and the translation
of the mobility diary into a mobility trajectory. We propose a data-driven
algorithm which constructs a diary generator from real data, capturing the
tendency of individuals to follow or break their routine. We also propose a
trajectory generator based on the concept of preferential exploration and
preferential return. We instantiate DITRAS with the proposed diary and
trajectory generators and compare the resulting algorithm with real data and
synthetic data produced by other generative algorithms, built by instantiating
DITRAS with several combinations of diary and trajectory generators. We show
that the proposed algorithm reproduces the statistical properties of real
trajectories in the most accurate way, making a step forward the understanding
of the origin of the spatio-temporal patterns of human mobility.

categories: cs.SI cs.LG physics.data-an physics.soc-ph stat.OT


title:
Double resonant absorption measurement of acetylene symmetric
  vibrational states probed with cavity ring down spectroscopy

abstract:
  A novel mid-infrared/near-infrared double resonant absorption setup for
studying infrared-inactive vibrational states is presented. A strong
vibrational transition in the mid-infrared region is excited using an idler
beam from a singly resonant continuous-wave optical parametric oscillator, to
populate an intermediate vibrational state. High output power of the optical
parametric oscillator and the strength of the mid-infrared transition result in
efficient population transfer to the intermediate state, which allows measuring
secondary transitions from this state with a high signal-to-noise ratio. A
secondary, near-infrared transition from the intermediate state is probed using
cavity ring down spectroscopy, which provides high sensitivity in this
wavelength region. Due to the narrow linewidths of the excitation sources, the
rovibrational lines of the secondary transition are measured with sub-Doppler
resolution. The setup is used to access a previously unreported symmetric
vibrational state of acetylene, $\nu_1+\nu_2+\nu_3+\nu_4^1+\nu_5^{-1}$ in the
normal mode notation. Single-photon transitions to this state from the
vibrational ground state are forbidden. Ten lines of the newly measured state
are observed and fitted with the linear least-squares method to extract the
band parameters. The vibrational term value was measured to be at 9775.0018(45)
$\text{cm}^{-1}$, the rotational parameter $B$ was 1.162222 $\text{cm}^{-1}$,
and the quartic centrifugal distortion parameter $D$ was 3.998(62)$\times
10^{-6} \text{cm}^{-1}$, where the numbers in the parenthesis are one-standard
errors in the least significant digits.


title:
On the estimation of stellar parameters with uncertainty prediction from
  Generative Artificial Neural Networks: application to Gaia RVS simulated
  spectra

abstract:
  Aims. We present an innovative artificial neural network (ANN) architecture,
called Generative ANN (GANN), that computes the forward model, that is it
learns the function that relates the unknown outputs (stellar atmospheric
parameters, in this case) to the given inputs (spectra). Such a model can be
integrated in a Bayesian framework to estimate the posterior distribution of
the outputs. Methods. The architecture of the GANN follows the same scheme as a
normal ANN, but with the inputs and outputs inverted. We train the network with
the set of atmospheric parameters (Teff, logg, [Fe/H] and [alpha/Fe]),
obtaining the stellar spectra for such inputs. The residuals between the
spectra in the grid and the estimated spectra are minimized using a validation
dataset to keep solutions as general as possible. Results. The performance of
both conventional ANNs and GANNs to estimate the stellar parameters as a
function of the star brightness is presented and compared for different
Galactic populations. GANNs provide significantly improved parameterizations
for early and intermediate spectral types with rich and intermediate
metallicities. The behaviour of both algorithms is very similar for our sample
of late-type stars, obtaining residuals in the derivation of [Fe/H] and
[alpha/Fe] below 0.1dex for stars with Gaia magnitude Grvs<12, which accounts
for a number in the order of four million stars to be observed by the Radial
Velocity Spectrograph of the Gaia satellite. Conclusions. Uncertainty
estimation of computed astrophysical parameters is crucial for the validation
of the parameterization itself and for the subsequent exploitation by the
astronomical community. GANNs produce not only the parameters for a given
spectrum, but a goodness-of-fit between the observed spectrum and the predicted
one for a given set of parameters. Moreover, they allow us to obtain the full
posterior distribution...


title:
Epitaxial growth of complex oxides on silicon by enhanced surface
  diffusion in large area pulsed laser deposition

abstract:
  Homogeneous highly epitaxial LaSrMnO3 (LSMO) thin films have been grown on
Yttria-stabilized-Zirconia (YsZ) / CeO2 buffer layers on technological relevant
4" silicon wafers using a Twente Solid State Technology B.V. (TSST) developed
large area Pulsed Laser Deposition (PLD) setup. We study and show the results
of the effect of an additional SrRuO3 buffer layer on the growth temperature
dependent structural and magnetic properties of LSMO films. With the
introduction of a thin SrRuO3 layer on top of the buffer stack, LSMO films show
ferromagnetic behaviour for growth temperatures as low as 250C. We suggest that
occurrence of epitaxial crystal growth of LSMO at these low growth temperatures
can be understood by an improved surface diffusion, which ensures sufficient
intermixing of surface species for formation of the correct phase. This
intermixing is necessary because the full plume is collected on the 4" wafer
resulting in a compositional varying flux of species on the wafer, in contrast
to small scale experiments.


title: Occam's Razor Applied to the Petri Net Coverability Problem

abstract:
  The verification of safety properties for concurrent systems often reduces to
the coverability problem for Petri nets. This problem was shown to be
ExpSpace-complete forty years ago. Driven by the concurrency revolution, it has
regained a lot of interest over the last decade. In this paper, we propose a
generic and simple approach to solve this problem. Our method is inspired from
the recent approach of Blondin, Finkel, Haase and Haddad. Basically, we combine
forward invariant generation techniques for Petri nets with backward
reachability for well- structured transition systems. An experimental
evaluation demonstrates the efficiency of our approach.


title: Isospectral Reduction in Infinite Graphs

abstract:
  L. A. Bunimovich and B. Z. Webb developed a theory for transforming a finite
weighted graph while preserving its spectrum, referred as isospectral reduction
theory. In this work we extend this theory to a class of operators on Banach
spaces that include Markov type operators. We apply this theory to infinite
countable weighted graphs admitting a finite structural set to calculate the
stationary measures of a family of countable Markov chains.


title: Restricted Poisson Algebras

abstract:
  We re-formulate Bezrukavnikov-Kaledin's definition of a restricted Poisson
algebra, provide some natural and interesting examples, and discuss connections
with other research topics.


title: Geoneutrinos and reactor antineutrinos at SNO+

abstract:
  In the heart of the Creighton Mine near Sudbury (Canada), the SNO+ detector
is foreseen to observe almost in equal proportion electron antineutrinos
produced by U and Th in the Earth and by nuclear reactors. SNO+ will be the
first long baseline experiment to measure a reactor signal dominated by CANDU
cores ($\sim$55\% of the total reactor signal), which generally burn natural
uranium. Approximately 18\% of the total geoneutrino signal is generated by the
U and Th present in the rocks of the Huronian Supergroup-Sudbury Basin: the
60\% uncertainty on the signal produced by this lithologic unit plays a crucial
role on the discrimination power on the mantle signal as well as on the
geoneutrino spectral shape reconstruction, which can in principle provide a
direct measurement of the Th/U ratio in the Earth.


title: QCD emergent from spontaneous breakdown of relativity

abstract:
  Spontaneous violation of relativistic invariance of the vacuum can derive
quantum chromodynamics from an U(1) Higgs model including fermions, if the
emergent theory is Lorentz invariant. In this model, the vacuum becomes
anisotropic, and a fermion created on a triplet of spin-one vacua acquires
degeneracy analogous to the color degrees of freedom. The Nambu-Goldstone
bosons originating from the breakdown of rotational symmetry provide the quasi
fermions with SU(3)$\times$U(1) effective interactions, which are interpretable
as mediated by gluons and photons. The confinement of quasi quarks as well as
that of Nambu-Goldstone gluons follow from the Lorentz invariance of the
emergent theory.


title: Projection effects in coronal dimmings and associated EUV wave event

abstract:
  We investigate the high-speed ($v >$ 1000 km s$^{-1}$) extreme-ultraviolet
(EUV) wave associated with an X1.2 flare and coronal mass ejection (CME) from
NOAA active region 11283 on 2011 September 6 (SOL2011-09-06T22:12). This EUV
wave features peculiar on-disk signatures, in particular we observe an
intermittent "disappearance" of the front for 120 s in SDO/AIA 171, 193, 211
{\AA} data, whereas the 335 {\AA} filter, sensitive to hotter plasmas
(T$\sim$2.5 MK), shows a continuous evolution of the wave front. The eruption
was also accompanied by localized coronal dimming regions. We exploit the
multi-point quadrature position of SDO and STEREO-A, to make a thorough
analysis of the EUV wave evolution, with respect to its kinematics and
amplitude evolution and reconstruct the SDO line-of-sight (LOS) direction of
the identified coronal dimming regions in STEREO-A. We show that the observed
intensities of the dimming regions in SDO/AIA depend on the structures that are
lying along their LOS and are the combination of their individual intensities,
e.g. the expanding CME body, the enhanced EUV wave and CME front. In this
context, we conclude that the intermittent disappearance of the EUV wave in the
AIA 171, 193, 211 {\AA} filters, which are channels sensitive to plasma with
temperatures below $\sim$2 MK is also caused by such LOS integration effects.
These observations clearly demonstrate that single-view image data provide us
with limited insight to correctly interpret coronal features.


title: Indoor occupancy estimation from carbon dioxide concentration

abstract:
  This paper presents an indoor occupancy estimator with which we can estimate
the number of real-time indoor occupants based on the carbon dioxide (CO2)
measurement. The estimator is actually a dynamic model of the occupancy level.
To identify the dynamic model, we propose the Feature Scaled Extreme Learning
Machine (FS-ELM) algorithm, which is a variation of the standard Extreme
Learning Machine (ELM) but is shown to perform better for the occupancy
estimation problem. The measured CO2 concentration suffers from serious spikes.
We find that pre-smoothing the CO2 data can greatly improve the estimation
accuracy. In real applications, however, we cannot obtain the real-time
globally smoothed CO2 data. We provide a way to use the locally smoothed CO2
data instead, which is real-time available. We introduce a new criterion, i.e.
$x$-tolerance accuracy, to assess the occupancy estimator. The proposed
occupancy estimator was tested in an office room with 24 cubicles and 11 open
seats. The accuracy is up to 94 percent with a tolerance of four occupants.


title: Time evolution of Renyi entropy under the Lindblad equation

abstract:
  In recent years, the Renyi entropy has repeatedly been discussed for
characterization of quantum critical states and entanglement. Here, time
evolution of the Renyi entropy is studied. A compact general formula is
presented for the lower bound on the entropy rate.


title:
Mixed weak type estimates: Examples and counterexamples related to a
  problem of E. Sawyer

abstract:
  We study mixed weighted weak-type inequalities for families of functions,
which can be applied to study classical operators in harmonic analysis. Our
main theorem extends the key result from D. Cruz-Uribe, J.M. Martell and C.
Perez, Weighted weak-type inequalities and a conjecture of Sawyer, Int. Math.
Res. Not., V. 30, 2005, 1849-1871.


title: On representation-finite gendo-symmetric biserial algebras

abstract:
  Gendo-symmetric algebras were introduced by Fang and Koenig as a
generalisation of symmetric algebras. Namely, they are endomorphism rings of
generators over a symmetric algebra. This article studies various algebraic and
homological properties of representation-finite gendo-symmetric biserial
algebras. We show that the associated symmetric algebras for these
gendo-symmetric algebras are Brauer tree algebras, and classify the generators
involved using Brauer tree combinatorics. We also study almost $\nu$-stable
derived equivalences, introduced by Hu and Xi, between representation-finite
gendo-symmetric biserial algebras. We classify these algebras up to almost
$\nu$-stable derived equivalence by showing that the representative of each
equivalence class can be chosen as a Brauer star with some additional
combinatorics. We also calculate the dominant, global, and Gorenstein
dimensions of these algebras. In particular, we found that
representation-finite gendo-symmetric biserial algebras are always
Iwanaga-Gorenstein algebras.


title: Onsager-corrected deep learning for sparse linear inverse problems

abstract:
  Deep learning has gained great popularity due to its widespread success on
many inference problems. We consider the application of deep learning to the
sparse linear inverse problem encountered in compressive sensing, where one
seeks to recover a sparse signal from a small number of noisy linear
measurements. In this paper, we propose a novel neural-network architecture
that decouples prediction errors across layers in the same way that the
approximate message passing (AMP) algorithm decouples them across iterations:
through Onsager correction. Numerical experiments suggest that our "learned
AMP" network significantly improves upon Gregor and LeCun's "learned ISTA"
network in both accuracy and complexity.


title: Interactive Illumination Invariance

abstract:
  Illumination effects cause problems for many computer vision algorithms. We
present a user-friendly interactive system for robust illumination-invariant
image generation. Compared with the previous automated illumination-invariant
image derivation approaches, our system enables users to specify a particular
kind of illumination variation for removal. The derivation of
illumination-invariant image is guided by the user input. The input is a stroke
that defines an area covering a set of pixels whose intensities are influenced
predominately by the illumination variation. This additional flexibility
enhances the robustness for processing non-linearly rendered images and the
images of the scenes where their illumination variations are difficult to
estimate automatically. Finally, we present some evaluation results of our
method.


title:
Robust Natural Language Processing - Combining Reasoning, Cognitive
  Semantics and Construction Grammar for Spatial Language

abstract:
  We present a system for generating and understanding of dynamic and static
spatial relations in robotic interaction setups. Robots describe an environment
of moving blocks using English phrases that include spatial relations such as
"across" and "in front of". We evaluate the system in robot-robot interactions
and show that the system can robustly deal with visual perception errors,
language omissions and ungrammatical utterances.


title:
4D Cardiac Ultrasound Standard Plane Location by Spatial-Temporal
  Correlation

abstract:
  Echocardiography plays an important part in diagnostic aid in cardiac
diseases. A critical step in echocardiography-aided diagnosis is to extract the
standard planes since they tend to provide promising views to present different
structures that are benefit to diagnosis. To this end, this paper proposes a
spatial-temporal embedding framework to extract the standard view planes from
4D STIC (spatial-temporal image corre- lation) volumes. The proposed method is
comprised of three stages, the frame smoothing, spatial-temporal embedding and
final classification. In first stage, an L 0 smoothing filter is used to
preprocess the frames that removes the noise and preserves the boundary. Then a
compact repre- sentation is learned via embedding spatial and temporal features
into a latent space in the supervised scheme considering both standard plane
information and diagnosis result. In last stage, the learned features are fed
into support vector machine to identify the standard plane. We eval- uate the
proposed method on a 4D STIC volume dataset with 92 normal cases and 93
abnormal cases in three standard planes. It demonstrates that our method
outperforms the baselines in both classification accuracy and computational
efficiency.


title:
On the Identification and Mitigation of Weaknesses in the Knowledge
  Gradient Policy for Multi-Armed Bandits

abstract:
  The Knowledge Gradient (KG) policy was originally proposed for online ranking
and selection problems but has recently been adapted for use in online decision
making in general and multi-armed bandit problems (MABs) in particular. We
study its use in a class of exponential family MABs and identify weaknesses,
including a propensity to take actions which are dominated with respect to both
exploitation and exploration. We propose variants of KG which avoid such
errors. These new policies include an index heuristic which deploys a KG
approach to develop an approximation to the Gittins index. A numerical study
shows this policy to perform well over a range of MABs including those for
which index policies are not optimal. While KG does not make dominated actions
when bandits are Gaussian, it fails to be index consistent and appears not to
enjoy a performance advantage over competitor policies when arms are correlated
to compensate for its greater computational demands.


title:
A family of well-behaved Karmarkar spacetime describing interior of
  relativistic stars

abstract:
  We are presenting a family of new exact solutions for relativistic
anisotropic stellar objects by considering four dimensional spacetime embedded
in five dimensional Pseudo Euclidean space known as Class I solutions. These
solutions are well-behaved in all respects, satisfy all energy conditions and
the resulting compactness parameter is also within Buchdahl limit. The
well-behaved nature of the solutions for a particular star solely depends on
index n. We have discussed the solutions in detail for the neutron star XTE
J1739-285 (M = 1.51M$\odot$, R = 10.9 km). For this particular star, the
solution is well behaved in all respects for $8 \le n \le 20$. However, the
solutions with n < 8 possess increasing trend of sound speed and the solutions
belong to n > 20 disobey causality condition. Further, the well-behaved nature
of the solutions for PSR J0348+0432 (2.01M$\odot$, 11 km), EXO 1785-248
(1.3M$\odot$, 8.85 km) and Her X-1 (0.85M$\odot$, 8.1 km) are specified by the
index n with limits $24 \le n \le 54$, $1.5 \le n \le 4$ and $0.8 \le n \le
2.7$ respectively.


title: Some features of a Schwarzchild Black Hole from a Snyder perspective

abstract:
  In this paper, the consequences of introducing a deformed Snyder-Kepler
potential in the Schwarzchild metric are investigated. After this modification,
it is obtained a dynamically depending horizon with different penetration
radius for massive particles and light rays in radial orbits. In the case of
circular orbits, they all remain untouched.


title:
Universal enveloping algebras and Poincar\'e-Birkhoff-Witt theorem for
  involutive Hom-Lie algebras

abstract:
  A Hom-type algebra is called involutive if its Hom map is multiplicative and
involutive. In this paper, we obtain an explicit construction of the free
involutive Hom-associative algebra on a Hom-module. We then apply this
construction to obtain the universal enveloping algebra of an involutive
Hom-Lie algebra. Finally we obtain a Poincar\'e-Birkhoff-Witt theorem for the
enveloping associative algebra of an involutive Hom-Lie algebra.


title: Anomaly Detection and Localisation using Mixed Graphical Models

abstract:
  We propose a method that performs anomaly detection and localisation within
heterogeneous data using a pairwise undirected mixed graphical model. The data
are a mixture of categorical and quantitative variables, and the model is
learned over a dataset that is supposed not to contain any anomaly. We then use
the model over temporal data, potentially a data stream, using a version of the
two-sided CUSUM algorithm. The proposed decision statistic is based on a
conditional likelihood ratio computed for each variable given the others. Our
results show that this function allows to detect anomalies variable by
variable, and thus to localise the variables involved in the anomalies more
precisely than univariate methods based on simple marginals.


title: Person Re-identification for Real-world Surveillance Systems

abstract:
  Appearance based person re-identification in a real-world video surveillance
system with non-overlapping camera views is a challenging problem for many
reasons. Current state-of-the-art methods often address the problem by relying
on supervised learning of similarity metrics or ranking functions to implicitly
model appearance transformation between cameras for each camera pair, or group,
in the system. This requires considerable human effort to annotate data.
Furthermore, the learned models are camera specific and not transferable from
one set of cameras to another. Therefore, the annotation process is required
after every network expansion or camera replacement, which strongly limits
their applicability. Alternatively, we propose a novel modeling approach to
harness complementary appearance information without supervised learning that
significantly outperforms current state-of-the-art unsupervised methods on
multiple benchmark datasets.


title: Non-archimedean normal families

abstract:
  We present several results on the compactness of the space of morphisms
between analytic spaces in the sense of Berkovich. We show that under certain
conditions on the source, every sequence of analytic maps having an affinoid
target has a subsequence that converges pointwise to a continuous map. We also
study the class of continuous maps that arise in this way. Locally, they turn
analytic after a certain base change. We give some applications of these
results to the dynamics of an endomorphism f of the projective space. We define
the Fatou set as the normality locus of the family of the iterates {f n }. We
then generalize to the non-Archimedan setting a theorem of Ueda stating that
every Fatou component is hyperbolically imbedded in the projective space.


title: A solid-state single-photon filter

abstract:
  A strong limitation of linear optical quantum computing is the probabilistic
operation of two-quantum bit gates based on the coalescence of
indistinguishable photons. A route to deterministic operation is to exploit the
single-photon nonlinearity of an atomic transition. Through engineering of the
atom-photon interaction, phase shifters, photon filters and photon- photon
gates have been demonstrated with natural atoms. Proofs of concept have been
reported with semiconductor quantum dots, yet limited by inefficient
atom-photon interfaces and dephasing. Here we report on a highly efficient
single-photon filter based on a large optical non-linearity at the single
photon level, in a near-optimal quantum-dot cavity interface. When probed with
coherent light wavepackets, the device shows a record nonlinearity threshold
around $0.3 \pm 0.1$ incident photons. We demonstrate that directly reflected
pulses consist of 80% single-photon Fock state and that the two- and
three-photon components are strongly suppressed compared to the single-photon
one.


title:
Hilbert function space splittings on domains with infinitely many
  variables

abstract:
  We present an approach to defining Hilbert spaces of functions depending on
infinitely many variables or parameters, with emphasis on a weighted tensor
product construction based on stable space splittings, The construction has
been used in an exemplary way for guiding dimension- and scale-adaptive
algorithms in application areas such as statistical learning theory, reduced
order modeling, and information-based complexity. We prove results on compact
embeddings, norm equivalences, and the estimation of $epsilon$-dimensions. A
new condition for the equivalence of weighted ANOVA and anchored norms is also
given.


title:
Search for squarks and gluinos in events with hadronically decaying tau
  leptons, jets and missing transverse momentum in proton-proton collisions at
  $\sqrt{s}=13$ TeV recorded with the ATLAS detector

abstract:
  A search for supersymmetry in events with large missing transverse momentum,
jets, and at least one hadronically decaying tau lepton has been performed
using 3.2 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}=13$ TeV
recorded by the ATLAS detector at the Large Hadron Collider in 2015. Two
exclusive final states are considered, with either exactly one or at least two
tau leptons. No excess over the Standard Model prediction is observed in the
data. Results are interpreted in the context of gauge-mediated supersymmetry
breaking and a simplified model of gluino pair production with tau-rich cascade
decays, substantially improving on previous limits. In the GMSB model
considered, supersymmetry-breaking scale ($\Lambda$) values below 92 TeV are
excluded at the 95% confidence level, corresponding to gluino masses below 2000
GeV. For large values of $\tan\beta$, values of $\Lambda$ up to 107 TeV and
gluino masses up to 2300 GeV are excluded. In the simplified model, gluino
masses are excluded up to 1570 GeV for neutralino masses around 100 GeV.
Neutralino masses up to 700 GeV are excluded for all gluino masses between 800
GeV and 1500 GeV, while the strongest exclusion of 750 GeV is achieved for
gluino masses around 1400 GeV.


title: Causal inference in partially linear structural equation models

abstract:
  We consider identifiability of partially linear additive structural equation
models with Gaussian noise (PLSEMs) and estimation of distributionally
equivalent models to a given PLSEM. Thereby, we also include robustness results
for errors in the neighborhood of Gaussian distributions. Existing
identifiability results in the framework of additive SEMs with Gaussian noise
are limited to linear and nonlinear SEMs, which can be considered as special
cases of PLSEMs with vanishing nonparametric or parametric part, respectively.
We close the wide gap between these two special cases by providing a
comprehensive theory of the identifiability of PLSEMs by means of (A) a
graphical, (B) a transformational, (C) a functional and (D) a causal ordering
characterization of PLSEMs that generate a given distribution P. In particular,
the characterizations (C) and (D) answer the fundamental question to which
extent nonlinear functions in additive SEMs with Gaussian noise restrict the
set of potential causal models and hence influence the identifiability. On the
basis of the transformational characterization (B) we provide a score-based
estimation procedure that outputs the graphical representation (A) of the
distribution equivalence class of a given PLSEM. We derive its
(high-dimensional) consistency and demonstrate its performance on simulated
datasets.


title:
Fitting logistic multilevel models with crossed random effects via
  Bayesian Integrated Nested Laplace Approximations: a simulation study

abstract:
  Fitting cross-classified multilevel models with binary response is
challenging. In this setting a promising method is Bayesian inference through
Integrated Nested Laplace Approximations (INLA), which performs well in several
latent variable models. Therefore we devise a systematic simulation study to
assess the performance of INLA with cross-classified logistic data under
different scenarios defined by the magnitude of the random effects variances,
the number of observations, the number of clusters, and the degree of
cross-classification. In the simulations INLA is systematically compared with
the popular method of Maximum Likelihood via Laplace Approximation. By an
application to the classical salamander mating data, we compare INLA with the
best performing methods. Given the computational speed and the generally good
performance, INLA turns out to be a valuable method for fitting the considered
cross-classified models.


title: The chiral anomaly in real space

abstract:
  The chiral anomaly is based on a non-conserved chiral charge and can happen
in Dirac fermion systems under the influence of external electromagnetic
fields. In this case, the spectral flow leads to a transfer of right- to
left-moving excitations or vice versa. The corresponding transfer of chiral
particles happens in momentum space. We here describe an intriguing way to
introduce the chiral anomaly into real space. Our system consists of two
quantum dots that are formed at the helical edge of a quantum spin Hall
insulator on the basis of three magnetic impurities. Such a setup gives rise to
fractional charges which we show to be sharp quantum numbers for large barrier
strength. Interestingly, it is possible to map the system onto a quantum spin
Hall ring in the presence of a flux pierced through the ring where the relative
angle between the magnetization directions of the impurities takes the role of
the flux. The chiral anomaly in this system is then directly related to the
excess occupation of particles in the two quantum dots. This analogy allows us
to predict an observable consequence of the chiral anomaly in real space.


title:
Nonconforming P1 elements on distorted triangulations: Lower bounds for
  the discrete energy norm error

abstract:
  Compared to conforming P1 finite elements, nonconforming P1 finite element
discretizations are thought to be less sensitive to the appearance of distorted
triangulations. E.g., optimal-order discrete $H^1$ norm best approximation
error estimates for $H^2$ functions hold for arbitrary triangulations. However,
similar estimates for the error of the Galerkin projection for second-order
elliptic problems show a dependence on the maximum angle of all triangles in
the triangulation. We demonstrate on the example of a special family of
distorted triangulations that this dependence is essential, and due to the
deterioration of the consistency error. We also provide examples of sequences
of triangulations such that the nonconforming P1 Galerkin projections for a
Poisson problem with polynomial solution do not converge or converge at
arbitrarily slow speed. The results complement analogous findings for
conforming P1 elements.


title: The global derived period map

abstract:
  Abstract. We develop the global period map in the context of derived
geometry, generalising Griffiths' classical period map as well as the
infinitesimal derived period map. We begin by constructing the derived period
domain which classifies Hodge filtrations and enhances the classical period
domain. We analyze the monodromy action. Then we associate to any polarized
smooth projective map of derived stacks a canonical morphism of derived
analytic stacks from the base into the quotient of the derived period domain by
monodromy. We conclude the paper by discussing a few examples and a derived
Torelli problem. In the appendix we describe how to present derived analytic
Artin stacks as hypergroupoids, which may be of independent interest.


title: Test of non-Newtonian gravitational force at micrometer range

abstract:
  We report an experimental test of non-Newtonian gravitational forces at mi-
crometer range. To experimentally subtract off the Casimir force and the
electrostatic force background, differential force measurements were performed
by sensing the lateral force between a gold sphere and a density modulated
source mass using a soft cantilever. The current sensitivity is limited by the
patch electrostatic force, which is further improved by two dimensional (2D)
force mapping. The preliminary result sets a model independent constraint on
the Yukawa type force at this range.


title: Boundary terms of the Einstein-Hilbert action

abstract:
  The Einstein-Hilbert action for general relativity is not well posed in terms
of the metric $g_{ab}$ as a dynamical variable. There have been many proposals
to obtain an well posed action principle for general relativity, e.g., addition
of the Gibbons-Hawking-York boundary term to the Einstein-Hilbert action. These
boundary terms are dependent on what one fixes on the boundary and in
particular on spacetime dimensions as well. Following recent works of
Padmanabhan we will introduce two new variables to describe general relativity
and the action principle with these new dynamical variables will turn out to be
well posed. Then we will connect these dynamical variables and boundary term
obtained thereof to existing literature and shall comment on a few properties
of Einstein-Hilbert action which might have been unnoticed earlier in the
literature. Before concluding with future prospects and discussions, we will
perform a general analysis of the boundary term of Einstein-Hilbert action for
null surfaces as well.


title: Testing Lorentz Symmetry using Chiral Perturbation Theory

abstract:
  We consider the low-energy effects of a selected set of Lorentz- and
CPT-violating quark and gluon operators by deriving the corresponding chiral
effective lagrangian. Using this effective lagrangian, low-energy hadronic
observables can be calculated. We apply this to magnetometer experiments and
derive the best bounds on some of the Lorentz-violating coefficients. We point
out that progress can be made by studying the nucleon-nucleon potential, and by
considering storage-ring experiments for deuterons and other light nuclei.


title: Stability Analysis for the Virtual Element Method

abstract:
  We analyse the Virtual Element Methods (VEM) on a simple elliptic model
problem, allowing for more general meshes than the one typically considered in
the VEM literature. For instance, meshes with arbitrarily small edges (with
respect to the parent element diameter), can be dealt with. Our general
approach applies to different choices of the stability form, including, for
example, the "classical" one introduced in [L. Beirao da Veiga, F. Brezzi, A.
Cangiani, G. Manzini, L. D. Marini, and A. Russo, Basic principles of virtual
element methods, Math. Models Methods Appl. Sci. 23 (2013), no. 1, 199-214],
and a recent one presented in [Wriggers, P., Rust, W.T., and Reddy, B.D., A
virtual element method for contact, submitted for publication]. Finally, we
show that the stabilization term can be simplified by dropping the contribution
of the internal-to-the-element degrees of freedom. The resulting stabilization
form, involving only the boundary degrees of freedom, can be used in the VEM
scheme without affecting the stability and convergence properties. The
numerical tests are in accordance with the theoretical predictions.


title: Multiplicity bound of Singular Spectrum for higher rank Anderson models

abstract:
  In this work, we prove a bound on multiplicity of the singular spectrum for
certain class of Anderson Hamiltonians. The class of operator is
$H^\omega=\Delta+\sum_{n\in\mathbb{Z}^d}\omega_n P_n$ on the Hilbert space
$\ell^2(\mathbb{Z}^d)$, where $\Delta$ is discrete laplacian, $P_n$ are
projection onto $\ell^2(\{x\in\mathbb{Z}^d:n_il_i<x_i\leq (n_i+1)l_i\})$ for
some $l_1,\cdots,l_d\in\mathbb{N}$ and $\{\omega_n\}_n$ are i.i.d real bounded
random variables following absolutely continuous distribution. We prove that
the multiplicity of singular spectrum is bounded above by $2^d-d$ independent
of $\{l_i\}_{i=1}^d$. When $l_i+1\not\in 2\mathbb{N}\cup3\mathbb{N}$ for all
$i$ and $gcd(l_i+1,l_j+1)=1$ for $i\neq j$, we also prove that the singular
spectrum is simple.


title: Elastocapillary bending of microfibers around liquid droplets

abstract:
  We report on the elastocapillary deformation of flexible microfibers in
contact with liquid droplets. A fiber is observed to bend more as the size of
the contacting droplet is increased. At a critical droplet size, proportional
to the bending elastocapillary length, the fiber is seen to spontaneously wind
around the droplet. To rationalize these observations, we invoke a minimal
model based on elastic beam theory, and find agreement with experimental data.
Further energetic considerations provide a consistent prediction for the
winding criterion.


title:
Convexity of Level Sets of Minimal Graph on Space Form with Nonnegative
  Curvature

abstract:
  For the minimal graph defined on a convex ring in the space form with
nonnegative curvature, we obtain the regularity and the strict convexity about
its level sets by the continuity method.


title: Reduction methods for the bienergy

abstract:
  This paper, in which we develop ideas introduced in \cite{MR}, focuses on
\emph{reduction methods} (basically, group actions or, more generally,
simmetries) for the bienergy. This type of techniques enable us to produce
examples of critical points of the bienergy by reducing the study of the
relevant fourth order PDE's system to ODE's. In particular, we shall study
rotationally symmetric biharmonic conformal diffeomorphisms between
\emph{models}. Next, we will adapt the reduction method to study an ample class
of $G-$invariant immersions into the Euclidean space. At present, the known
instances in these contexts are far from reaching the depth and variety of
their companions which have provided fundamental solutions to classical
problems in the theories of harmonic maps and minimal immersions. However, we
think that these examples represent an important starting point which can
inspire further research on biharmonicity. In this order of ideas, we end this
paper with a discussion of some open problems and possible directions for
further developments.


title: Closed-Loop Estimation of Oscillator g-Sensitivity in a GNSS/IMU System

abstract:
  We propose a simple method for estimating crystal oscillator g-sensitivity in
inertially aided Global Navigation Satellite System (GNSS) receivers. It does
not require any specific equipment, like GNSS signal simulators or rate tables.
The method is based on analyzing closed-loop phase tracking errors. This
enables us to utilize the actual GNSS signal as the frequency reference,
despite the presence of an unknown Doppler shift in it. The method has been
successfully applied to the calibration of an oven-controlled crystal
oscillator.


title:
Dynamic Time Warping and Geometric Edit Distance: Breaking the Quadratic
  Barrier

abstract:
  Dynamic Time Warping (DTW) and Geometric Edit Distance (GED) are basic
similarity measures between curves or general temporal sequences (e.g., time
series) that are represented as sequences of points in some metric space $(X,
\mathrm{dist})$. The DTW and GED measures are massively used in various fields
of computer science, computational biology, and engineering. Consequently, the
tasks of computing these measures are among the core problems in P. Despite
extensive efforts to find more efficient algorithms, the best-known algorithms
for computing the DTW or GED between two sequences of points in $X =
\mathbb{R}^d$ are long-standing dynamic programming algorithms that require
quadratic runtime, even for the one-dimensional case $d = 1$, which is perhaps
one of the most used in practice.
  In this paper, we break the nearly 50 years old quadratic time bound for
computing DTW or GED between two sequences of $n$ points in $\mathbb{R}$, by
presenting deterministic algorithms that run in $O\left( n^2 / \log\log n
\right)$ time. Our algorithms can be extended to work also for higher
dimensional spaces $\mathbb{R}^d$, for any constant $d$, when the underlying
distance-metric $\mathrm{dist}$ is polyhedral (e.g., $L_1, L_\infty$).


title:
Parsec-scale HI absorption structure in a low-redshift galaxy seen
  against a Compact Symmetric Object

abstract:
  We present global VLBI observations of the 21-cm transition of atomic
hydrogen seen in absorption against the radio source J0855+5751. The foreground
absorber (SDSS~J085519.05+575140.7) is a dwarf galaxy at $z$ = 0.026. As the
background source is heavily resolved by VLBI, the data allow us to map the
properties of the foreground HI gas with a spatial resolution of 2pc. The
absorbing gas corresponds to a single coherent structure with an extent
$>$35pc, but we also detect significant and coherent variations, including a
change in the HI optical depth by a factor of five across a distance of
$\leq$6pc. The large size of the structure provides support for the Heiles &
Troland model of the ISM, as well as its applicability to external galaxies.
The large variations in HI optical depth also suggest that caution should be
applied when interpreting $T_S$ measurements from radio-detected DLAs. In
addition, the distorted appearance of the background radio source is indicative
of a strong jet-cloud interaction in its host galaxy. We have measured its
redshift ($z$ = 0.54186) using optical spectroscopy on the William Herschel
Telescope and this confirms that J0855+5751 is a FRII radio source with a
physical extent of $<$1kpc and supports the previous identification of this
source as a Compact Symmetric Object. These sources often show absorption
associated with the host galaxy and we suggest that both HI and OH should be
searched for in J0855+5751.


title: Magnetic Field Amplification During the Common Envelope Phase

abstract:
  During the common envelope (CE) phase, a giant star in a binary system
overflows its Roche lobe and unstable mass transfer leads to a spiral-in of the
companion, resulting in a close binary system or in a merger of the stellar
cores. Dynamo processes during the CE phase have been proposed as a mechanism
to generate magnetic fields that are important for forming magnetic white
dwarfs (MWDs) and for shaping planetary nebulae. Here, we present the first
magnetohydrodynamics simulations of the dynamical spiral-in during a CE phase.
We find that magnetic fields are strongly amplified in the accretion stream
around the $1M_\odot$ companion as it spirals into the envelope of a $2M_\odot$
RG. This leads to field strengths of 10 to 100 kG throughout the envelope after
120 d. The magnetic field amplification is consistent with being driven by the
magnetorotational instability. The field strengths reached in our simulation
make the magnetic field interesting for diagnostic purposes, but they are
dynamically irrelevant. They are also too small to explain the formation of the
highest fields found in MWDs, but may be relevant for luminous red novae, and
detecting magnetic fields in these events would support the scenario as
proposed here.


title: Non-Anomalous Semigroups and Real Numbers

abstract:
  Motivated by intuitive properties of physical quantities, the notion of a
non-anomalous semigroup is formulated. These are totally ordered semigroups
where there are no `infinitesimally close' elements. The real numbers are then
defined as the terminal object in a closely related category. From this
definition a field structure on $\mathbb R$ is derived, relating multiplication
to morphisms between non-anomalous semigroups.


title: Static Spherically Symmetric Wormholes in $f(R,T)$ Gravity

abstract:
  In this work, we explore wormhole solutions in $f(R,T)$ theory of gravity,
where $R$ is the scalar curvature and $T$ is the trace of stress-energy tensor
of matter. To investigate this, we consider static spherically symmetric
geometry with matter contents as anisotropic, isotropic and barotropic fluids
in three separate cases. By taking into account Starobinsky $f(R)$ model , we
analyze the behavior of energy conditions for these different kind of fluids.
It is shown that the wormhole solutions can be constructed without exotic
matter in few regions of spacetime. We also give the graphical illustration of
obtained results and discuss the equilibrium picture for anisotropic case only.
It is concluded that the wormhole solutions with anisotropic matter are
realistic and stable in this gravity.


title:
Visualizing Rotations and Composition of Rotations with Rodrigues'
  Vector

abstract:
  The purpose of this paper is to show that the mathematical treatment of three
dimensional rotations can be simplified, and its geometrical understanding
improved, by using the Rodrigues' vector representation. We present a novel
geometrical interpretation of the Rodrigues' vector. Based on this
interpretation and simple geometrical considerations, we derive Euler
Rodrigues' formula, Cayley's rotation formula, and the composition law for
finite rotations. The level of this discussion should be suitable for
undergraduate physics or engineering courses where rotations are discussed.


title:
Coherent Long-Range Thermoelectrics in Nonadiabatic Driven Quantum
  Systems

abstract:
  We investigate direct energy and heat transfer between two distant sites of a
triple quantum dot connected to reservoirs, where one of the edge dots is
driven by an ac-gate voltage. We theoretically propose how to implement heat
and cooling engines mediated by long range photoassisted transport.
Additionally we propose a simple set up to heat up coherently the two
reservoirs symmetrically and a mechanism to store energy in the closed system.
The present proposals can be experimentally implemented and easily controlled
by tunning the external parameters.


title: On the gravity dual of the light-front vacuum

abstract:
  Building on a previous conjecture, we argue that the holographic dual of the
light-front vacuum state of a superconformal field theory quantized in the
front form of dynamics contains the Kaigorodov spacetime, which is nothing but
a pp-wave propagating in AdS. Evidence in favor of this conjecture is
presented. In particular we verify the matching of global symmetries and
discuss the contribution of the zero mode sector in both sides of the
correspondence.


title:
Generalization of Numerical Series and its Relationship with the
  Polynomial Equations and Artithmetic Trapezoids

abstract:
  The close relationship among the polynomial functions and Fibonacci numerical
sequences is shown in this paper. These numerical sequences are defined by the
recurrence equation $x_{k + n} = \displaystyle\sum_{j = 0}^{n-1}\alpha_j x_{k +
j}$, where $n$ is the polynomial degree and $\alpha$'s, the polynomial
coefficients. The arithmetic trapezoid resulting from the recurrence equations
is also shown. This trapezoid is nothing but a generalization of Pascal's
Triangle. Trapezoid is a convenient name because the form it appears does not
have the `upper end` of a usual triangle. This study shows that each polynomial
generates infinite sequences, and that each sequence generates only a single
arithmetic trapezoid.


title:
Flexible A-scan rate MHz OCT: Computational downscaling by coherent
  averaging

abstract:
  In order to realize fast OCT-systems with adjustable line rate, we
investigate averaging of image data from an FDML based MHz-OCT-system. The line
rate can be reduced in software and traded in for increased system sensitivity
and image quality. We compare coherent and incoherent averaging to effectively
scale down the system speed of a 3.2 MHz FDML OCT system to around 100 kHz in
postprocessing. We demonstrate that coherent averaging is possible with MHz
systems without special interferometer designs or digital phase stabilisation.
We show OCT images of a human finger knuckle joint in vivo with very high
quality and deep penetration.


title: Use of Hydrophobic-Hydrophobic Interactions for Direct Graphene Transfer

abstract:
  A new large-area wet transfer method to transfer graphene directly onto
UHMWPE membranes without organic-coating, thermal treatment or other mediated
substrate was developed. This method completely avoids the problems of
PMMA-residue and possible PMMA coating induced tear-off by harnessing
hydrophobic-hydrophobic interactions between graphene and UHMWPE, which is one
of most facile and cheapest transfer methods that are currently available,
especially for large-area graphene preparation and transfer. Multi-layer
sandwich structure composite membrane of graphene and UHMWPE with desired
number of layers can also be easily prepared by repeating the transfer method.
The most significant applications of this transfer method lie on that it
facilitates thin polymer membranes the possibilities to be directly observed
with high magnification by electron microscopes, such as SEM and TEM. Thus the
crystallization and phase-behavior of polymers including UHMWPE can be
investigated with real-time and in-situ morphological observations, even in the
presence of their solvent and with the need of thermal treatment. Morphologies
and mechanical properties of stretched graphene/UHMWPE layered composite
membranes were investigated, and strengthening effect of graphene on one side
and both sides was observed.


title: Oscillatory convection and limitations of the Boussinesq approximation

abstract:
  We determine the asymptotic conditions under which the Boussinesq
approximation is valid for oscillatory convection in a rapidly rotating fluid.
In the astrophysically relevant parameter regime of small Prandtl number, we
show that the Boussinesq prediction for the onset of convection is valid only
under much more restrictive conditions than those that are usually assumed. In
the case of an ideal gas, we recover the Boussinesq results only if the ratio
of the domain height to a typical scale height is much smaller than the Prandtl
number. This requires an extremely shallow domain in the astrophysical
parameter regime. Other commonly-used "sound-proof" approximations generally
perform no better than the Boussinesq approximation. The exception is a
particular implementation of the pseudo-incompressible approximation, which
predicts the correct instability threshold beyond the range of validity of the
Boussinesq approximation.


title: Restricted Stirling permutations

abstract:
  In this paper, we study the generating functions for the number of pattern
restricted Stirling permutations with a given number of plateaus, descents and
ascents. Properties of the generating functions, including symmetric properties
and explicit formulas are studied. Combinatorial explanations are given for
some equidistributions.


title:
Thermal Infrared Imaging and Atmospheric Modeling of VHS
  J125601.92-125723.9 b: Evidence for Moderately Thick Clouds and Equilibrium
  Carbon Chemistry in a Hierarchical Triple System

abstract:
  We present and analyze Subaru/IRCS L' and M' images of the nearby M dwarf VHS
J125601.92-125723.9 (VHS 1256), which was recently claimed to have a ~11 M_Jup
companion (VHS 1256 b) at ~102 au separation. Our AO images partially resolve
the central star into a binary, whose components are nearly equal in brightness
and separated by 0.106" +/- 0.001". VHS 1256 b occupies nearly the same near-IR
color-magnitude diagram position as HR 8799 bcde and has a comparable L'
brightness. However, it has a substantially redder H - M' color, implying a
relatively brighter M' flux density than for the HR 8799 planets and suggesting
that non-equilibrium carbon chemistry may be less significant in VHS 1256 b. We
successfully match the entire SED (optical through thermal infrared) for VHS
1256 b to atmospheric models assuming chemical equilibrium, models which failed
to reproduce HR 8799 b at 5 microns. Our modeling favors slightly thick clouds
in the companion's atmosphere, although perhaps not quite as thick as those
favored recently for HR 8799 bcde. We estimate that the system is at least
older than 200 Myr and the masses of the stars comprising the central binary
are at least 58 M_Jup each. Moreover, we find some of the properties of VHS
1256 are inconsistent with the recent suggestion that it is a member of the AB
Dor moving group. Given the possible ranges in distance (12.7 pc vs. 17.1 pc),
the lower mass limit for VHS 1256 b ranges from 10.5 - 26.2 M_Jup. Our
detection limits rule out companions more massive than VHS 1256 b exterior to
6-8 au, placing significant limits on and providing some evidence against a
second, more massive companion that may have scattered the wide-separation
companion to its current location. VHS 1256 is most likely a very low mass
hierarchical triple system, and could be the third such system in which all
components reside in the brown dwarf mass regime.


title:
Laplacian cut-offs, porous and fast diffusion on manifolds and other
  applications

abstract:
  We construct exhaustion and cut-off functions with controlled gradient and
Laplacian on manifolds with Ricci curvature bounded from below by a (possibly
unbounded) nonpositive function of the distance from a fixed reference point,
without any assumptions on the topology or the injectivity radius. Along the
way we prove a generalization of the Li-Yau gradient estimate which is of
independent interest. We then apply our cut-offs to the study of the fast and
porous media diffusion, of $L^q$-properties of the gradient and of the
self-adjointness of Schroedinger-type operators.


title:
Dynamics of two disks settling in a two-dimensional narrow channel: From
  periodic motion to vertical chain in Oldroyd-B fluid

abstract:
  In this article we present a numerical study of the dynamics of two disks
settling in a narrow vertical channel filled with Oldroyd-B fluid. Two kinds of
particle dynamics are obtained: (i) periodic interaction between two disks and
(ii) the chain formation of two disks. For the periodic interaction of two
disks, two different motions are obtained: (a) two disks stay far apart and
interact periodically and (b) two disks interact closely and then far apart in
a periodic way, like the drafting, kissing and tumbling of two disks
sedimenting in Newtonian fluid, due to the lack of strong enough elastic force.
For the formation of two disk chain occurred at higher values of the elasticity
number, it is either a tilted chain or a vertical chain. The tilted chain can
be obtained for either that the elasticity number is less than the critical
value for having the vertical chain or that the Mach number is greater than the
critical value for a long body to fall broadside-on. Hence the values of the
elasticity number and the Mach number determine whether the the chain can be
formed and the orientation of the chain.


title: A Positivstellensatz for Sums of Nonnegative Circuit Polynomials

abstract:
  Recently, the second and the third author developed sums of nonnegative
circuit polynomials (SONC) as a new certificate of nonnegativity for real
polynomials, which is independent of sums of squares.
  In this article we show that the SONC cone is full-dimensional in the cone of
nonnegative polynomials. We establish a Positivstellensatz which guarantees
that every polynomial which is positive on a given compact, semi-algebraic set
can be represented by the constraints of the set and SONC polynomials. Based on
this Positivstellensatz we provide a hierarchy of lower bounds converging
against the minimum of a polynomial on a given compact set $K$. Moreover, we
show that these new bounds can be computed efficiently via interior point
methods using results about relative entropy functions.


title:
On the Modeling of Error Functions as High Dimensional Landscapes for
  Weight Initialization in Learning Networks

abstract:
  Next generation deep neural networks for classification hosted on embedded
platforms will rely on fast, efficient, and accurate learning algorithms.
Initialization of weights in learning networks has a great impact on the
classification accuracy. In this paper we focus on deriving good initial
weights by modeling the error function of a deep neural network as a
high-dimensional landscape. We observe that due to the inherent complexity in
its algebraic structure, such an error function may conform to general results
of the statistics of large systems. To this end we apply some results from
Random Matrix Theory to analyse these functions. We model the error function in
terms of a Hamiltonian in N-dimensions and derive some theoretical results
about its general behavior. These results are further used to make better
initial guesses of weights for the learning algorithm.


title:
Heralding pure single photons: a comparision between counter-propagating
  and co-propagating twin photons

abstract:
  We investigate the possibility of generating pure heralded single photons
through spontaneous parametric down-conversion comparing the
counter-propagating geometry studied in [1] with more conventional
co-propagating configurations which enhance the purity of the heralded photon
state through the technique of group-velocity matching. We estimate the Schmidt
number associated to the temporal modes as a function of the pump pulse
duration for three particular configurations, showing how the different
phase-matching conditions influences the degree of separability that can be
achieved.


title:
A stabilized chip-scale Kerr frequency comb via a high-Q reference
  photonic microresonator

abstract:
  We stabilize a chip-scale Si3N4 phase-locked Kerr frequency comb via locking
the pump laser to an independent stable high-Q reference microresonator and
locking the comb spacing to an external microwave oscillator. In this comb, the
pump laser shift induces negligible impact on the comb spacing change. This
scheme is a step towards miniaturization of the stabilized Kerr comb system as
the microresonator reference can potentially be integrated on-chip. Fractional
instability of the optical harmonics of the stabilized comb is limited by the
microwave oscillator used for comb spacing lock below 1 s averaging time and
coincides with the pump laser drift in the long term.


title:
Acoustic Holographic Rendering with Two-dimensional Metamaterial-based
  Passive Phased Array

abstract:
  Acoustic holographic rendering in complete analogy with optical holography
are useful for various applications, ranging from multi-focal lensing,
multiplexed sensing and synthesizing three-dimensional complex sound fields.
Conventional approaches rely on a large number of active transducers and phase
shifting circuits. In this paper we show that by using passive metamaterials as
subwavelength pixels, holographic rendering can be achieved without cumbersome
circuitry and with only a single transducer, thus significantly reducing system
complexity. Such metamaterial-based holograms can serve as versatile platforms
for various advanced acoustic wave manipulation and signal modulation, leading
to new possibilities in acoustic sensing, energy deposition and medical
diagnostic imaging.


title:
Detection of False Data Injection Attacks in Smart Grid under Colored
  Gaussian Noise

abstract:
  In this paper, we consider the problems of state estimation and false data
injection detection in smart grid when the measurements are corrupted by
colored Gaussian noise. By modeling the noise with the autoregressive process,
we estimate the state of the power transmission networks and develop a
generalized likelihood ratio test (GLRT) detector for the detection of false
data injection attacks. We show that the conventional approach with the
assumption of Gaussian noise is a special case of the proposed method, and thus
the new approach has more applicability. {The proposed detector is also tested
on an independent component analysis (ICA) based unobservable false data attack
scheme that utilizes similar assumptions of sample observation.} We evaluate
the performance of the proposed state estimator and attack detector on the IEEE
30-bus power system with comparison to conventional Gaussian noise based
detector. The superior performance of {both observable and unobservable false
data attacks} demonstrates the effectiveness of the proposed approach and
indicates a wide application on the power signal processing.


title: Non-homogeneous space-time fractional Poisson processes

abstract:
  The space-time fractional Poisson process (STFPP), defined by Orsingher and
Poilto in \cite{sfpp}, is a generalization of the time fractional Poisson
process (TFPP) and the space fractional Poisson process (SFPP). We study the
fractional generalization of the non-homogeneous Poisson process and call it
the non-homogeneous space-time fractional Poisson process (NSTFPP). We compute
their {\it pmf} and generating function and investigate the associated
differential equation. The limit theorems and the law of iterated logarithm for
the NSTFPP process are studied. We study the distributional properties, the
asymptotic expansion of the correlation function of the non-homogeneous time
fractional Poisson process (NTFPP) and subsequently investigate the long-range
dependence (LRD) property of a special NTFPP. We investigate the limit theorem
and the LRD property for the fractional non-homogeneous Poisson process (FNPP),
studied by Leonenko et. al. (2016). Finally, we present some simulated sample
paths of the NSTFPP process.


title:
Doubly Accelerated Methods for Faster CCA and Generalized
  Eigendecomposition

abstract:
  We study $k$-GenEV, the problem of finding the top $k$ generalized
eigenvectors, and $k$-CCA, the problem of finding the top $k$ vectors in
canonical-correlation analysis. We propose algorithms $\mathtt{LazyEV}$ and
$\mathtt{LazyCCA}$ to solve the two problems with running times linearly
dependent on the input size and on $k$.
  Furthermore, our algorithms are DOUBLY-ACCELERATED: our running times depend
only on the square root of the matrix condition number, and on the square root
of the eigengap. This is the first such result for both $k$-GenEV or $k$-CCA.
We also provide the first gap-free results, which provide running times that
depend on $1/\sqrt{\varepsilon}$ rather than the eigengap.


title: Undiscounted optimal stopping with unbounded rewards

abstract:
  We study optimal stopping of Feller-Markov processes to maximise an
undiscounted functional consisting of running and terminal rewards. In a
finite-time horizon setting, we extend classical results to unbounded rewards.
In infinite horizon, we resort to ergodic structure of the underlying process.
When the running reward is mildly penalising for delaying stopping (i.e., its
expectation under the invariant measure is negative), we show that an optimal
stopping time exists and is given in a standard form as the time of first
entrance to a closed set. This paper generalises Palczewski, Stettner (2014),
Stoch Proc Appl 124(12) 3887-3920, by relaxing boundedness of rewards.


title: Diophantine properties of groups of toral automorphisms

abstract:
  We prove sharp estimates in a shrinking target problem for the action of an
arbitrary subgroup $\Gamma$ of $SL_2(\mathbb{Z})$ on the 2-torus. This can also
be viewed as a non-commutative Diophantine approximation problem. The methods
require constructing spectrally optimal random walks on groups acting properly
cocompactly on Gromov hyperbolic spaces. Additionally, using Fourier analysis
we give estimates for the same problem in higher dimensions.


title: An Empirical Study of Customer Spillover Learning about Service Quality

abstract:
  "Spillover" learning is defined as customers' learning about the quality of a
service (or product) from their previous experiences with similar yet not
identical services. In this paper, we propose a novel, parsimonious and general
Bayesian hierarchical learning framework for estimating customers' spillover
learning. We apply our model to a one-year shipping/sales historical data
provided by a world-leading third party logistics company and study how
customers' experiences from shipping on a particular route affect their future
decisions about shipping not only on that route, but also on other routes
serviced by the same logistics company. Our empirical results are consistent
with information spillovers driving customer choices. Customers also display an
asymmetric response such that they are more sensitive to delays than early
deliveries. In addition, we find that customers are risk averse being more
sensitive to their uncertainty about the mean service quality than to the
intrinsic variability of the service. Finally, we develop policy simulation
studies to show the importance of accounting for customer learning when a firm
considers service quality improvement decisions.


title: Shared multi-processor scheduling

abstract:
  We study shared multi-processor scheduling problem where each job can be
executed on its private processor and simultaneously on one of many processors
shared by all jobs in order to reduce the job's completion time due to
processing time overlap. The total weighted overlap of all jobs is to be
maximized. The problem models subcontracting scheduling in supply chains and
divisible load scheduling in computing. We show that synchronized schedules
that complete each job at the same time on its private processor and shared
processors, if any is actually used by the job, include optimal schedules. We
prove that the problem is NP-hard in the strong sense for jobs with arbitrary
weights, and we give an efficient, polynomial-time algorithm for the problem
with equal weights.


title: Protocol-independent critical node detection

abstract:
  This article explains how to construct a protocol-independent model for
passing traffic through a wireless network with a single channel carrier sense
multiple access/collision detection (CSMA/CD) media access model.


title: Modeling wireless network routing using sheaves

abstract:
  This article explains how to construct a sheaf model for passing traffic
through a wireless network with a single channel carrier sense multiple
access/collision detection (CSMA/CD) media access model.


title: Playing with the enveloping algebra of supersymmetry

abstract:
  In this paper we show how to obtain from a scalar superfield its first
component via a similarity transformation. We prove that in D=4 the generators
of this similarity transformation live in the enveloping algebra of
supersymmetry while for D=1 they belong to the basic algebra.


title:
Constructing a Natural Language Inference Dataset using Generative
  Neural Networks

abstract:
  Natural Language Inference is an important task for Natural Language
Understanding. It is concerned with classifying the logical relation between
two sentences. In this paper, we propose several text generative neural
networks for generating text hypothesis, which allows construction of new
Natural Language Inference datasets. To evaluate the models, we propose a new
metric -- the accuracy of the classifier trained on the generated dataset. The
accuracy obtained by our best generative model is only 2.7% lower than the
accuracy of the classifier trained on the original, human crafted dataset.
Furthermore, the best generated dataset combined with the original dataset
achieves the highest accuracy. The best model learns a mapping embedding for
each training example. By comparing various metrics we show that datasets that
obtain higher ROUGE or METEOR scores do not necessarily yield higher
classification accuracies. We also provide analysis of what are the
characteristics of a good dataset including the distinguishability of the
generated datasets from the original one.


title:
Boundary scattering effects on magnetotransport of narrow metallic wires
  and films

abstract:
  Electron transport in thin metallic wires and films is strongly influenced by
the quality of their surface. Weak localization and magnetoconductivity are
also sensitive to the electron scattering at the edges of the sample. We study
weak localization effects in a two-dimensional electron gas patterned in the
form of a narrow quasi-one-dimensional channel in transverse magnetic field.
The most general boundary conditions interpolating between the limits of mirror
and diffuse edge scattering are assumed. We calculate magnetoconductivity for
an arbitrary width of the sample including the cases of diffusive and ballistic
lateral transport as well as the crossover between them. We find that in a
broad range of parameters, the electron mobility is limited by the boundary
roughness while the magnetotransport is only weakly influenced by the quality
of the edges. In addition, we calculate magnetoconductivity for a metallic
cylinder in the transverse field and a quasi-two-dimensional metallic film in
the parallel field.


title:
New Approach to Metal-Insulator Phase Transition Kinetics in Magnetic
  Field

abstract:
  The metal--insulator phase transition is considered on the basis of
Ginzburg-Landau type equations with two different order parameters. An
inclusion of magnetic field in this picture is an important step for
understanding of behavior of the metal--insulator phase transition kinetics.
The magnetic field leads to various singularities of the surface tension and
results in drastic variations of the phase transition kinetics. The strongest
singularity is due to Landau diamagnetism and determines anomalous features of
MI transition kinetics. This singularity supports the well known experimental
fact that almost all semimetals behave like diamagnetic materials.


title: Photon Emission Near Extreme Kerr Black Holes

abstract:
  Ongoing astronomical efforts extract physical properties of black holes from
electromagnetic emissions in their near-vicinity. This requires finding the
null geodesics which extend from the near-horizon region out to a distant
observatory. In general these can only be found numerically. In this paper, for
the interesting special case of extremally spinning Kerr black holes, we use an
emergent near-horizon conformal symmetry to find near-superradiant geodesics
analytically.


title:
Automatic Detection of Solar Photovoltaic Arrays in High Resolution
  Aerial Imagery

abstract:
  The quantity of small scale solar photovoltaic (PV) arrays in the United
States has grown rapidly in recent years. As a result, there is substantial
interest in high quality information about the quantity, power capacity, and
energy generated by such arrays, including at a high spatial resolution (e.g.,
counties, cities, or even smaller regions). Unfortunately, existing methods for
obtaining this information, such as surveys and utility interconnection
filings, are limited in their completeness and spatial resolution. This work
presents a computer algorithm that automatically detects PV panels using very
high resolution color satellite imagery. The approach potentially offers a
fast, scalable method for obtaining accurate information on PV array location
and size, and at much higher spatial resolutions than are currently available.
The method is validated using a very large (135 km^2) collection of publicly
available [1] aerial imagery, with over 2,700 human annotated PV array
locations. The results demonstrate the algorithm is highly effective on a
per-pixel basis. It is likewise effective at object-level PV array detection,
but with significant potential for improvement in estimating the precise
shape/size of the PV arrays. These results are the first of their kind for the
detection of solar PV in aerial imagery, demonstrating the feasibility of the
approach and establishing a baseline performance for future investigations.


title: Near-wall diffusion tensor of an axisymmetric colloidal particle

abstract:
  Hydrodynamic interactions with confining boundaries often lead to drastic
changes in the diffusive behaviour of microparticles in suspensions. For
axially symmetric particles, earlier numerical studies have suggested a simple
form of the near-wall diffusion matrix which depends on the distance and
orientation of the particle with respect to the wall, which is usually
calculated numerically. In this work, we derive explicit analytical formulae
for the dominant correction to the bulk diffusion tensor of an axially
symmetric colloidal particle due to the presence of a nearby no-slip wall. The
relative correction scales as powers of inverse wall-particle distance and its
angular structure is represented by simple polynomials in sines and cosines of
the particle's inclination angle to the wall. We analyse the correction for
translational and rotational motion, as well as the translation-rotation
coupling. Our findings provide a simple approximation to the anisotropic
diffusion tensor near a wall, which completes and corrects relations known from
earlier numerical and theoretical findings.


title:
Quark-Gluon tagging with Shower Deconstruction: Unearthing dark matter
  and Higgs couplings

abstract:
  The separation of quark and gluon initiated jets can be an important way to
improve the sensitivity in searches for new physics or in measurements of Higgs
boson properties. We present a simplified version of the shower deconstruction
approach as a novel observable for quark-gluon tagging. Assuming
topocluster-like objects as input, we compare our observable with energy
correlation functions and find a favorable performance for a large variety of
jet definitions. When applied to dark matter searches in mono-jet final states
limitations from small signal-to-background ratios can be overcome. We also
show that quark-gluon tagging is an alternative way of separating weak boson
from gluon-fusion production in the process p + p -> H + jet + jet + X


title: A Topological Lowpass Filter for Quasiperiodic Signals

abstract:
  This article presents a two-stage topological algorithm for recovering an
estimate of a quasiperiodic function from a set of noisy measurements. The
first stage of the algorithm is a topological phase estimator, which detects
the quasiperiodic structure of the function without placing additional
restrictions on the function. By respecting this phase estimate, the algorithm
avoids creating distortion even when it uses a large number of samples for the
estimate of the function.


title: Canonical bases of quantum Schubert cells and their symmetries

abstract:
  The goal of this work is to provide an elementary construction of the
canonical basis $\mathbf B(w)$ in each quantum Schubert cell~$U_q(w)$ and to
establish its invariance under modified Lusztig's symmetries. To that effect,
we obtain a direct characterization of the upper global basis $\mathbf B^{up}$
in terms of a suitable bilinear form and show that $\mathbf B(w)$ is contained
in $\mathbf B^{up}$ and its large part is preserved by modified Lusztig's
symmetries.