title:
Construction of Triple-GEM Detectors Using Commercially Manufactured
  Large GEM Foils

abstract:
  Many experiments are currently using or proposing to use large area GEM foils
in their detectors, which is creating a need for commercially available GEM
foils. Currently CERN is the only main distributor of large GEM foils, however
with the growing interest in GEM technology keeping up with the increasing
demand for GEMs will be difficult. Thus the commercialization of GEMs up to 50
$\times$ 50 cm$^2$ has been established by Tech-Etch Inc. of Plymouth, MA, USA
using the single-mask technique. The electrical performance and optical quality
of the single-mask GEM foils have been found to be on par with those produced
by CERN. The next critical step towards validating the Tech-Etch single-mask
GEM foils is to test their performance under physics conditions. These
measurements will allow us to quantify and compare the gain and efficiency of
the detector to other triple-GEM detectors. This will be done by constructing
several single-mask triple-GEM detectors, using foils manufactured by
Tech-Etch, which follow the design used by the STAR Forward GEM Tracker (FGT).
These detectors will investigate ways in which to further decrease the material
budget and increase the efficiency of the detector by incorporating perforated
Kapton spacer rings rather than G10 spacing grids to reduce the dead area of
the detector. The materials and tooling needed to assemble the triple-GEM
detectors have been acquired. The GEM foils have been electrically tested, and
a handful have been optically scanned. We found these results to be consistent
with GEM foils produced by CERN. With the success of these initial tests,
construction of the triple-GEM detectors is now under way.


title:
Hybrid Learning of Optical Flow and Next Frame Prediction to Boost
  Optical Flow in the Wild

abstract:
  CNN-based optical flow estimation has attracted attention recently, mainly
due to its impressively high frame rates. These networks perform well on
synthetic datasets, but they are still far behind the classical methods in
real-world videos. This is because there is no ground truth optical flow for
training these networks on real data. In this paper, we boost CNN-based optical
flow estimation in real scenes with the help of the freely available
self-supervised task of next-frame prediction. To this end, we train the
network in a hybrid way, providing it with a mixture of synthetic and real
videos. With the help of a sample-variant multi-tasking architecture, the
network is trained on different tasks depending on the availability of
ground-truth. We also experiment with the prediction of "next-flow" instead of
estimation of the current flow, which is intuitively closer to the task of
next-frame prediction and yields favorable results. We demonstrate the
improvement in optical flow estimation on the real-world KITTI benchmark.
Additionally, we test the optical flow indirectly in an action classification
scenario. As a side product of this work, we report significant improvements
over state-of-the-art in the task of next-frame prediction.


title: Physical model of dimensional regularization

abstract:
  We explicitly construct fractals of dimension 4-epsilon on which dimensional
regularization approximates scalar-field-only quantum-field-theory amplitudes.
The construction does not require fractals to be Lorentz-invariant in any
sense, and we argue that there probably is no Lorentz-invariant fractal of
dimension greater than 2. We derive dimensional regularization's power-law
screening first for fractals obtained by removing voids from 3-dimensional
Euclidean space. The derivation applies techniques from elementary dielectric
theory. Surprisingly, fractal geometry by itself does not guarantee the
appropriate power-law behavior; boundary conditions at fractal voids also play
an important role. We then extend the derivation to 4-dimensional Minkowski
space. We comment on generalization to nonscalar fields, and speculate about
implications for quantum gravity.


title:
PoseAgent: Budget-Constrained 6D Object Pose Estimation via
  Reinforcement Learning

abstract:
  State-of-the-art computer vision algorithms often achieve efficiency by
making discrete choices about which hypotheses to explore next. This allows
allocation of computational resources to promising candidates, however, such
decisions are non-differentiable. As a result, these algorithms are hard to
train in an end-to-end fashion. In this work we propose to learn an efficient
algorithm for the task of 6D object pose estimation. Our system optimizes the
parameters of an existing state-of-the art pose estimation system using
reinforcement learning, where the pose estimation system now becomes the
stochastic policy, parametrized by a CNN. Additionally, we present an efficient
training algorithm that dramatically reduces computation time. We show
empirically that our learned pose estimation procedure makes better use of
limited resources and improves upon the state-of-the-art on a challenging
dataset. Our approach enables differentiable end-to-end training of complex
algorithmic pipelines and learns to make optimal use of a given computational
budget.


title:
Online Reinforcement Learning for Real-Time Exploration in Continuous
  State and Action Markov Decision Processes

abstract:
  This paper presents a new method to learn online policies in continuous
state, continuous action, model-free Markov decision processes, with two
properties that are crucial for practical applications. First, the policies are
implementable with a very low computational cost: once the policy is computed,
the action corresponding to a given state is obtained in logarithmic time with
respect to the number of samples used. Second, our method is versatile: it does
not rely on any a priori knowledge of the structure of optimal policies. We
build upon the Fitted Q-iteration algorithm which represents the $Q$-value as
the average of several regression trees. Our algorithm, the Fitted Policy
Forest algorithm (FPF), computes a regression forest representing the Q-value
and transforms it into a single tree representing the policy, while keeping
control on the size of the policy using resampling and leaf merging. We
introduce an adaptation of Multi-Resolution Exploration (MRE) which is
particularly suited to FPF. We assess the performance of FPF on three classical
benchmarks for reinforcement learning: the "Inverted Pendulum", the "Double
Integrator" and "Car on the Hill" and show that FPF equals or outperforms other
algorithms, although these algorithms rely on the use of particular
representations of the policies, especially chosen in order to fit each of the
three problems. Finally, we exhibit that the combination of FPF and MRE allows
to find nearly optimal solutions in problems where $\epsilon$-greedy approaches
would fail.


title:
Anisotropic crystallization in solution processed chalcogenide thin film
  by linearly polarized laser

abstract:
  The low activation energy associated with amorphous chalcogenide structures
offers broad tunability of material properties with laser-based or thermal
processing. In this paper, we study near-bandgap laser induced anisotropic
crystallization in solution processed arsenic sulfide. The modified electronic
bandtail states associated with laser irritation lead to a distinctive
photoluminescence spectrum, compared to thermally annealed amorphous glass.
Laser crystalized materials exhibit a periodic subwavelength ripples structure
in transmission electron microscopy experiments and show polarization dependent
photoluminescence. Analysis of the local atomic structure of these materials
using laboratory-based X-ray pair distribution function analysis indicates that
laser irradiation causes a slight rearrangement at the atomic length scale,
with a small percentage of S-S homopolar bonds converting to As-S heteropolar
bonds. These results highlight fundamental differences between laser and
thermal processing in this important class of materials.


title: Homotopy theory with *categories

abstract:
  We construct model category structures on various types of (marked)
*-categories. These structures are used to present the infinity categories of
(marked) *-categories obtained by inverting (marked) unitary equivalences. We
use this presentation to explicitly calculate the \infty-categorical G-fixed
points and G-orbits for G-equivariant (marked) *-categories.


title:
Are we close to put the anomalous perihelion precessions from Verlinde's
  emergent gravity to the test?

abstract:
  In the framework of the emergent gravity scenario by Verlinde, it was
recently observed by Liu and Prokopec that, among other things, an anomalous
pericenter precession would affect the orbital motion of a test particle
orbiting an isolated central body. Here, it is shown that, if it were real, its
expected magnitude for the inner planets of the Solar System would be at the
same level of the present-day accuracy in constraining any possible deviations
from their standard perihelion precessions as inferred from long data records
spanning about the last century. The most favorable situation for testing the
Verlinde-type precession seems to occur for Mars. Indeed, according to recent
versions of the EPM and INPOP planetary ephemerides, non-standard perihelion
precessions, of whatsoever physical origin, which are larger than some $\approx
0.02-0.11$ milliarcseconds per century are not admissible, while the putative
precession predicted by Liu and Prokopec amounts to $0.09$ milliarcseconds per
century. Other potentially interesting astronomical and astrophysical scenarios
like, e.g., the Earth's LAGEOS II artificial satellite, the double pulsar
system PSR J0737-3039A/B and the S-stars orbiting the Supermassive Black Hole
in Sgr A$^\ast$ are, instead, not viable because of the excessive smallness of
the predicted effects for them.

categories: gr-qc astro-ph.EP hep-th physics.space-ph


title: Depth-Based Visual Servoing Using Low-Accurate Arm

abstract:
  This paper proposes a visual-servoing method dedicated to grasping of
daily-life objects. In order to obtain an affordable solution, we use a
low-accurate robotic arm. Our method corrects errors by using an RGB-D sensor.
It is based on SURF invariant features which allows us to perform object
recognition at a high frame rate. We define regions of interest based on depth
segmentation, and we use them to speed-up the recognition and to improve
reliability. The system has been tested on a real-world scenario. In spite of
the lack of accuracy of all the components and the uncontrolled environment, it
grasps objects successfully on more than 95 percents of the trials.


title:
A model and sensitivity analysis of the quality economics of
  defect-detection techniques

abstract:
  One of the main cost factors in software development is the detection and
removal of defects. However, the relationships and influencing factors of the
costs and revenues of defect-detection techniques are still not well
understood. This paper proposes an analytical, stochastic model of the
economics of defect detection and removal to improve this understanding. The
model is able to incorporate dynamic as well as static techniques in contrast
to most other models of that kind. We especially analyse the model with
state-ofthe-art sensitivity analysis methods to (1) identify the most relevant
factors for model simplification and (2) prioritise the factors to guide
further research and measurements.


title:
Proxima Centauri reloaded: Unravelling the stellar noise in radial
  velocities

abstract:
  The detection and characterisation of Earth-like planets with Doppler signals
of the order of 1 m/s currently represent one of the greatest challenge for
extrasolar-planet hunters. As results for such findings are often
controversial, it is desirable to provide independent confirmations of the
discoveries. Testing different models for the suppression of non-Keplerian
stellar signals usually plaguing radial velocity data is essential to ensuring
findings are robust and reproducible. Using an alternative treatment of the
stellar noise to that discussed in the discovery paper, we re-analyse the
radial velocity dataset that led to the detection of a candidate terrestrial
planet orbiting the star Proxima Centauri. We aim to confirm the existence of
this outstanding planet, and test the existence of a second planetary signal.
Our technique jointly modelled Keplerian signals and residual correlated
signals in radial velocities using Gaussian processes. We analysed only radial
velocity measurements without including other ancillary data in the fitting
procedure. In a second step, we have compared our outputs with results coming
from photometry, to provide a consistent physical interpretation. Our analysis
was performed in a Bayesian framework to quantify the robustness of our
findings. We show that the correlated noise can be successfully modelled as a
Gaussian process regression, and contains a periodic term modulated on the
stellar rotation period and characterised by an evolutionary timescale of the
order of one year. Both findings appear to be robust when compared with results
obtained from archival photometry, thus providing a reliable description of the
noise properties. We confirm the existence of a coherent signal described by a
Keplerian orbit equation that can be attributed to the planet Proxima b [...]


title: Scattering amplitudes for dark and bright excitons

abstract:
  Using the composite boson many-body formalism that takes single-exciton
states rather than free carrier states as a basis, we derive the integral
equation fulfilled by the exciton-exciton effective scattering from which the
role of fermion exchanges can be unraveled. For excitons made of
$(\pm1/2)$-spin electrons and $(\pm3/2)$-spin holes, as in GaAs
heterostructures, one major result is that most spin configurations lead to
brightness-conserving scatterings with equal amplitude $\Delta$, in spite of
the fact that they involve different carrier exchanges. A brightness-changing
channel also exists when two opposite-spin excitons scatter: dark excitons
$(2,-2)$ can end either in the same dark states with an amplitude $\Delta_e$,
or in opposite-spin bright states $(1,-1)$, with a different amplitude
$\Delta_o$, the number of carrier exchanges being even or odd respectively.
Another major result is that these amplitudes are linked by a striking
relation, $\Delta_e+\Delta_o=\Delta$, which has decisive consequence for
exciton Bose-Einstein condensation. Indeed, this relation leads to the
conclusion that the exciton condensate can be optically observed through a
bright part only when excitons have a large dipole, that is, when the electrons
and holes are well separated in two adjacent layers.


title: Robust MIMO Beamforming for Cellular and Radar Coexistence

abstract:
  In this letter, we consider the coexistence and spectrum sharing between
downlink multi-user multiple-input-multiple-output (MU-MIMO) communication and
a MIMO radar. For a given performance requirement of the downlink communication
system, we design the transmit beamforming such that the detection probability
of the radar is maximized. While the original optimization problem is
non-convex, we exploit the monotonically increasing relationship of the
detection probability with the non-centrality parameter of the resulting
probability distribution to obtain a convex lower-bound optimization. The
proposed beamformer is designed to be robust to imperfect channel state
information (CSI). Simulation results verify that the proposed approach
facilitates the coexistence between radar and communication links, and
illustrates a scalable trade-off between the two systems' performance.


title:
A Unit Selection Methodology for Music Generation Using Deep Neural
  Networks

abstract:
  Several methods exist for a computer to generate music based on data
including Markov chains, recurrent neural networks, recombinancy, and grammars.
We explore the use of unit selection and concatenation as a means of generating
music using a procedure based on ranking, where, we consider a unit to be a
variable length number of measures of music. We first examine whether a unit
selection method, that is restricted to a finite size unit library, can be
sufficient for encompassing a wide spectrum of music. We do this by developing
a deep autoencoder that encodes a musical input and reconstructs the input by
selecting from the library. We then describe a generative model that combines a
deep structured semantic model (DSSM) with an LSTM to predict the next unit,
where units consist of four, two, and one measures of music. We evaluate the
generative model using objective metrics including mean rank and accuracy and
with a subjective listening test in which expert musicians are asked to
complete a forced-choiced ranking task. We compare our model to a note-level
generative baseline that consists of a stacked LSTM trained to predict forward
by one note.


title: Charm Production: Pole Mass or Running Mass?

abstract:
  We consider the role of the charm mass in PDF fits, and in particular the
reliability of recent determinations of the MSbar running mass from fits to
inclusive charm production data. We explain how the use of the pole mass, with
a charm PDF determined empirically, can reduce PDF uncertainties from charm
mass effects, and thereby lead to more reliable predictions for hard processes
at the LHC.


title:
Neural Machine Translation by Minimising the Bayes-risk with Respect to
  Syntactic Translation Lattices

abstract:
  We present a novel scheme to combine neural machine translation (NMT) with
traditional statistical machine translation (SMT). Our approach borrows ideas
from linearised lattice minimum Bayes-risk decoding for SMT. The NMT score is
combined with the Bayes-risk of the translation according the SMT lattice. This
makes our approach much more flexible than $n$-best list or lattice rescoring
as the neural decoder is not restricted to the SMT search space. We show an
efficient and simple way to integrate risk estimation into the NMT decoder
which is suitable for word-level as well as subword-unit-level NMT. We test our
method on English-German and Japanese-English and report significant gains over
lattice rescoring on several data sets for both single and ensembled NMT. The
MBR decoder produces entirely new hypotheses far beyond simply rescoring the
SMT search space or fixing UNKs in the NMT output.


title: Mathematics and liquid crystals

abstract:
  A review is given of some mathematical contributions, ideas and questions
concerning liquid crystals.


title: Robustness and Perturbations of Minimal Bases

abstract:
  Polynomial minimal bases of rational vector subspaces are a classical concept
that plays an important role in control theory, linear systems theory, and
coding theory. It is a common practice to arrange the vectors of any minimal
basis as the rows of a polynomial matrix and to call such matrix simply a
minimal basis. Very recently, minimal bases, as well as the closely related
pairs of dual minimal bases, have been applied to a number of problems that
include the solution of general inverse eigenstructure problems for polynomial
matrices, the development of new classes of linearizations and
$\ell$-ifications of polynomial matrices, and backward error analyses of
complete polynomial eigenstructure problems solved via a wide class of strong
linearizations. These new applications have revealed that although the
algebraic properties of minimal bases are rather well understood, their
robustness and the behavior of the corresponding dual minimal bases under
perturbations have not yet been explored in the literature, as far as we know.
Therefore, the main purpose of this paper is to study in detail when a minimal
basis $M(\lambda)$ is robust under perturbations, i.e., when all the polynomial
matrices in a neighborhood of $M(\lambda)$ are minimal bases, and, in this
case, how perturbations of $M(\lambda)$ change its dual minimal bases. In order
to study such problems, a new characterization of whether or not a polynomial
matrix is a minimal basis in terms of a finite number of rank conditions is
introduced and, based on it, we prove that polynomial matrices are generically
minimal bases with very specific properties. In addition, some applications of
the results of this paper are discussed.


title: On the SNR Variability in Noisy Compressed Sensing

abstract:
  Compressed sensing (CS) is a sampling paradigm that allows to simultaneously
measure and compress signals that are sparse or compressible in some domain.
The choice of a sensing matrix that carries out the measurement has a defining
impact on the system performance and it is often advocated to draw its elements
randomly. It has been noted that in the presence of input (signal) noise, the
application of the sensing matrix causes SNR degradation due to the noise
folding effect. In fact, it might also result in the variations of the output
SNR in compressive measurements over the support of the input signal,
potentially resulting in unexpected non-uniform system performance. In this
work, we study the impact of a distribution from which the elements of a
sensing matrix are drawn on the spread of the output SNR. We derive analytic
expressions for several common types of sensing matrices and show that the SNR
spread grows with the decrease of the number of measurements. This makes its
negative effect especially pronounced for high compression rates that are often
of interest in CS.


title: Solvable Quantum Grassmann Matrices

abstract:
  We explore systems with a large number of fermionic degrees of freedom
subject to non-local interactions. We study both vector and matrix-like models
with quartic interactions. The exact thermal partition function is expressed in
terms of an ordinary bosonic integral, which has an eigenvalue repulsion term
in the matrix case. We calculate real time correlations at finite temperature
and analyze the thermal phase structure. When possible, calculations are
performed in both the original Hilbert space as well as the bosonic picture,
and the exact map between the two is explained. At large $N$, there is a phase
transition to a highly entropic high temperature phase from a low temperature
low entropy phase. Thermal two-point functions decay in time in the high
temperature phase.


title: Operator Structures and Quantum One-Way LOCC Conditions

abstract:
  We conduct the first detailed analysis in quantum information of recently
derived operator relations from the study of quantum one-way local operations
and classical communications (LOCC). We show how operator structures such as
operator systems, operator algebras, and Hilbert C*-modules all naturally arise
in this setting, and we make use of these structures to derive new results and
new derivations of some established results in the study of LOCC. We also show
that perfect distinguishability under one-way LOCC and under arbitrary
operations is equivalent for several families of operators that appear jointly
in matrix and operator theory and quantum information theory.


title: An Optimization Framework For Online Ride-sharing Markets

abstract:
  Taxi services and product delivery services are instrumental for our modern
society. Thanks to the emergence of sharing economy, ride-sharing services such
as Uber, Didi, Lyft and Google's Waze Rider are becoming more ubiquitous and
grow into an integral part of our everyday lives. However, the efficiency of
these services are severely limited by the sub-optimal and imbalanced matching
between the supply and demand. We need a generalized framework and
corresponding efficient algorithms to address the efficient matching, and hence
optimize the performance of these markets. Existing studies for taxi and
delivery services are only applicable in scenarios of the one-sided market. In
contrast, this work investigates a highly generalized model for the taxi and
delivery services in the market economy (abbreviated as"taxi and delivery
market") that can be widely used in two-sided markets. Further, we present
efficient online and offline algorithms for different applications. We verify
our algorithm with theoretical analysis and trace-driven simulations under
realistic settings.


title:
Optical melting of the transverse Josephson plasmon: a comparison
  between bilayer and trilayer cuprates

abstract:
  We report on an investigation of the redistribution of interlayer coherence
in the trilayer cuprate Bi2Sr2Ca2Cu3O10. The experiment is performed under the
same apical-oxygen phonon excitation discussed in the past for the bilayer
cuprate YBa2Cu3O6.5. In Bi2Sr2Ca2Cu3O10, we observe a similar spectral weight
loss at the transverse plasma mode resonance seen in YBa2Cu3O6.5. However, this
feature is not accompanied by light-enhanced interlayer coherence that was seen
in YBa2Cu3O6+x, for which the transverse plasma mode is observed at equilibrium
even in the normal state. These new observations offer new experimental
perspective in the context of the physics of light-enhanced interlayer coupling
in various cuprates.


title:
A Software Reliability Model Based on a Geometric Sequence of Failure
  Rates

abstract:
  Software reliability models are an important tool in quality management and
release planning. There is a large number of different models that often
exhibit strengths in different areas. This paper proposes a model that is based
on a geometric sequence (or progression) of the failure rates of faults. This
property of the failure process was observed in practice at Siemens among
others and led to the development of the proposed model. It is described in
detail and evaluated using standard criteria. Most importantly, the model
performs constantly well over several projects in terms of its predictive
validity.


title: Localizing infinity-categories with hypercovers

abstract:
  Given an $\infty$-category with a set of weak equivalences which is stable
under pullback, we show that the mapping spaces of the corresponding
localization can be described as group completions of $\infty$-categories of
spans. Furthermore, we show how these $\infty$-categories of spans are the
mapping objects of an $(\infty, 2)$-category, which yields a Segal space model
for the localization after a Kan fibrant replacement.


title: DeepMind Lab

abstract:
  DeepMind Lab is a first-person 3D game platform designed for research and
development of general artificial intelligence and machine learning systems.
DeepMind Lab can be used to study how autonomous artificial agents may learn
complex tasks in large, partially observed, and visually diverse worlds.
DeepMind Lab has a simple and flexible API enabling creative task-designs and
novel AI-designs to be explored and quickly iterated upon. It is powered by a
fast and widely recognised game engine, and tailored for effective use by the
research community.


title:
The role of Cerenkov radiation in the pressure balance of cool core
  clusters of galaxies

abstract:
  Despite the substantial progress made recently in understanding the role of
AGN feedback and associated non-thermal effects, the precise mechanism that
prevents the core of some clusters of galaxies from collapsing catastrophically
by radiative cooling remains unidentified. In this paper we demonstrate that
the evolution of a cluster's cooling core, in terms of its density,
temperature, and magnetic field strength, inevitably enables the plasma
electrons there to quickly become Cerenkov loss dominated, with emission at the
radio frequency of $\lesssim$ 350 Hz, and with a rate considerably exceeding
free-free continuum and line emission. However, the same does not apply to the
plasmas at the cluster's outskirts, which lacks such radiation. Owing to its
low frequency, the radiation cannot escape, but because over the relevant scale
size of a Cerenkov wavelength the energy of an electron in the gas cannot
follow the Boltzmann distribution to the requisite precision to ensure
reabsorption always occurs slower than stimulated emission, the emitting gas
cools before it reheats. This leaves behind the radiation itself, trapped by
the overlying reflective plasma, yet providing enough pressure to maintain
quasi-hydrostatic equilibrium. The mass condensation then happens by
Rayleigh-Taylor instability, at a rate determined by the outermost radius where
Cerenkov radiation can occur. In this way, it is possible to estimate the rate
at $\ap 2 M_\odot$~year$^{-1}$, consistent with observational inference. Thus
the process appears to provide a natural solution to the long standing problem
of `cooling flow' in clusters; at least it offers another line of defense
against cooling and collapse, should gas heating by AGN feedback be inadequate
in some clusters


title: Polarization of top produced in particle decays in an arbitrary frame

abstract:
  In most of the models beyond the Standard Model, the top quark is expected to
be polarized when produced in the decay of some heavier particle, like the
gluino or the stop. The polarization is constructed, in an experiment or in
simulations, through the distribution of top decay products. Here, we propose
an estimator of top quark polarization that depends only on the kinematics of
it's mother particle, apart from its decay couplings to top quarks, and is
given in terms of the top polarization expected in the rest frame of the
decaying particle. This estimator allows one to estimate the top polarization
without performing a full simulation. We find this estimator is independent of
the production angle of the mother, top decay angle (for unpolarized mother),
and the spin of the mother particle. We study the quality of the estimator with
finite width of the mother particle via examples of gluinos and stops decaying
into top quark at LHC. We also point out how for the mass spectra of gluinos
and top squarks currently expected in a `natural' scenario, the polarization of
the top quarks produced in the gluino decays can uniquely track the mixing
angle in the stop sector.


title: Self-Learning Determinantal Quantum Monte Carlo Method

abstract:
  Self-learning Monte Carlo method [arXiv:1610.03137, 1611.09364] is a powerful
general-purpose numerical method recently introduced to simulate many-body
systems. In this work, we implement this method in the framework of
determinantal quantum Monte Carlo simulation of interacting fermion systems.
Guided by a self-learned bosonic effective action, our method uses a cumulative
update [arXiv:1611.09364] algorithm to sample auxiliary field configurations
quickly and efficiently. We demonstrate that self-learning determinantal Monte
Carlo method can reduce the auto-correlation time to as short as one near a
critical point, leading to $\mathcal{O}(N)$-fold speedup. This enables to
simulate interacting fermion system on a $100\times 100$ lattice for the first
time, and obtain critical exponents with high accuracy.


title:
Nonlinear interglitch dynamics, the braking index of the Vela pulsar and
  the time to the next glitch

abstract:
  The inter-glitch timing of the Vela pulsar is characterized by a constant
second derivative of the rotation rate. This takes over after the post-glitch
exponential relaxation, and is completed at about the time of the next glitch.
The vortex creep model explains the second derivatives in terms of non-linear
response to the glitch. We present inter-glitch timing fits to the present
sample covering 16 large glitches, taking into account the possibility that in
some glitches part of the step in spin-down rate may involve a "persistent
shift", as observed in the Crab pulsar. Modifying the expression for the time
between glitches with this hypothesis leads to better agreement with the
observed inter-glitch time intervals. We extrapolate the inter-glitch model
fits to obtain spin-down rates just prior to each glitch, and use these to
calculate the braking index n = 2.81 +/- 0.12. The next glitch should occur
around Dec. 22, 2017 +/- 197 days if no persistent shift is involved, but could
occur as early as July 27, 2016 +/- 152 days if the 2013 glitch gave rise to a
typical Vela persistent shift. Note added: Literally while we were submitting
the first version of this paper, on Dec. 12, 2016, we saw ATel # 9847
announcing a Vela pulsar glitch which has arrived 138 days after our prediction
with a persistent shift, within the 1 sigma uncertainty of 152 days.


title:
A Comparative Study of Multiwavelength Theoretical and Observed Light
  Curves of Cepheid Variables

abstract:
  We analyse the theoretical light curves of Cepheid variables at optical ({\it
UBVRI}) and near-infrared ({\it JKL}) wavelengths using the Fourier
decomposition and principal component analysis methods. The Cepheid light
curves are based on the full amplitude, nonlinear, convective hydrodynamical
models for chemical compositions representative of Cepheids in the Galaxy
($Y=0.28$, $Z=0.02$), Large Magellanic Cloud ($Y=0.25$, $Z=0.008$) and Small
Magellanic Cloud ($Y=0.25$, $Z=0.004$). We discuss the variation of light curve
parameters with different compositions and mass-luminosity levels as a function
of period and wavelength, and compare our results with observations. For a
fixed composition, the theoretical amplitude parameters decrease while the
phase parameters increase with wavelength, similar to the observed Fourier
parameters. The optical amplitude parameters obtained using canonical
mass-luminosity Cepheid models, exhibit a large offset with respect to the
observations for periods between 7-11 days, when compared to the non-canonical
mass-luminosity levels. The central minimum of the Hertzsprung progression for
amplitude parameters, shifts to the longer periods with decrease/increase in
metallicity/wavelength for both theoretical and observed light curves. The
principal components for Magellanic Clouds Cepheid models are consistent with
observations at optical wavelengths. We also observe two distinct populations
in the first principal component for optical and near-infrared wavelengths
while $J$-band contributes to both populations. Finally, we take into account
the variation in the convective efficiency by increasing the adopted mixing
length parameter from the standard 1.5 to 1.8. This results in a zero-point
offset in the bolometric mean magnitudes and in amplitude parameters (except
close to 10 days), reducing the systematically large difference in theoretical
amplitudes.


title: Phase Structure and Dynamics of QCD-- A Functional Perspective

abstract:
  The understanding of the phase structure and the fundamental properties of
QCD matter from its microscopic description requires appropriate
first-principle approaches. Here I review the progress towards a quantitative
first-principle continuum approach within the framework of the Functional
Renormalization group established by the fQCD collaboration. I focus on recent
quantitative results for quenched QCD and Yang-Mills theory in the vacuum
before addressing the calculation of dynamical quantities such as spectral
functions and transport coefficients in this framework.


title: A characterisation of octahedrality in Lipschitz-free spaces

abstract:
  We characterise the octahedrality of Lipschitz-free space norm in terms of a
new geometric property of the underlying metric space. We study the metric
spaces with and without this property. Quite surprisingly, metric spaces
without this property cannot embed isometrically into $\ell_1$ and similar
Banach spaces.


title: Generalizable Features From Unsupervised Learning

abstract:
  Humans learn a predictive model of the world and use this model to reason
about future events and the consequences of actions. In contrast to most
machine predictors, we exhibit an impressive ability to generalize to unseen
scenarios and reason intelligently in these settings. One important aspect of
this ability is physical intuition(Lake et al., 2016). In this work, we explore
the potential of unsupervised learning to find features that promote better
generalization to settings outside the supervised training distribution. Our
task is predicting the stability of towers of square blocks. We demonstrate
that an unsupervised model, trained to predict future frames of a video
sequence of stable and unstable block configurations, can yield features that
support extrapolating stability prediction to blocks configurations outside the
training set distribution


title: Conjugacy growth series for wreath product finitary symmetric groups

abstract:
  In recent work, Bacher and de la Harpe define and study conjugacy growth
series for finitary permutation groups. In two subsequent papers, Cotron,
Dicks, and Fleming study the congruence properties of some of these series. We
define a new family of conjugacy growth series for the finitary alternating
wreath product that are related to sums of modular forms of integer and
half-integral weights, the so-called \textit{mixed weight modular forms}. The
previous works motivate the study of congruences for these series. We prove
that congruences exist modulo powers of all primes $p \geq 5$. Furthermore, we
lay out a method for studying congruence properties for sums of mixed weight
modular forms in general.


title:
On possible small-x effects in the Kaluza-Klein graviton and radion
  production at high energies

abstract:
  We study the single graviton production at the CERN LHC using the
$k_T$-factorization approach of QCD. We consider the
Arkani-Hamed-Dimopoulos-Dvali scenario and Randall-Sundrum model with one
warped extra-dimension and derive the production amplitudes for spin-$2$
(Kaluza-Klein excitation of the graviton) and spin-$0$ (radion) states,
including subsequent graviton decay into the dilepton or diphoton pairs. We use
the transverse momentum dependent (unintegrated) parton densities in a proton
obtained from Ciafaloni-Catani-Fiorani-Marchesini (CCFM) evolution equation,
which resums the leading logarithmic small-$x$ corrections to the production
cross sections. We demonstrate that the small-$x$ effects can manifest
themselves in the different angular distributions of graviton decay products
and give some examples of how these distributions can look like at the LHC
energies.


title: A stochastic model for directional changes of swimming bacteria

abstract:
  In this work we introduce a stochastic model to describe directional changes
in the movement of swimming bacteria. We use the probability density function
(PDF) of turn angles, measured on tumbling wild-type {\it E. coli}, to build a
Langevin equation for the deflection of the bacterial body swimming in
isotropic media. We have solved this equation analytically by means of the
Green function method and shown that three parameters are sufficient to
describe the movement: the characteristic time, the steady-state solution and
the control parameter. We conclude that the tumble motion, which is manifested
as abrupt turns, is primarily caused by the rotational boost generated by the
flagellar motor and complementarily by the rotational diffusion introduced by
noise. We show that in the tumble motion the deflection is a non-stationary
stochastic process during times at which the tumbling occurs. By tuning the
control parameter our model is able to explain small turns of the bacteria
around their centres of mass along the run. We show that the deflection during
the run is an OrnsteinUhlenbeck process, which for typical run times is
stationary. We conclude that, along the run, the rotational boosts do not exist
and that only the rotational diffusion remains. Thus we have a single model to
explain the turns of through a critical value that can explain the transition
between the two turn behaviours. This model is the bacterium during the run or
tumble movements, through a control parameter that can be tuned also able to
explain in a very satisfactory way all available statistical experimental data,
such as PDFs and average values of turning angles times, of both run and tumble
motions.


title:
Spreadsheet Guardian: An Approach to Protecting Semantic Correctness
  throughout the Evolution of Spreadsheets

abstract:
  Spreadsheets are powerful tools which play a business-critical role in many
organizations. However, many bad decisions taken due to faulty spreadsheets
show that these tools need serious quality assurance. Furthermore, while
collaboration on spreadsheets for maintenance tasks is common, there has been
almost no support for ensuring that the spreadsheets remain correct during this
process.
  We have developed an approach named Spreadsheet Guardian which separates the
specification of spreadsheet test rules from their execution. By automatically
executing user-defined test rules, our approach is able to detect semantic
faults. It also protects all collaborating spreadsheet users from introducing
faults during maintenance, even if only few end-users specify test rules. To
evaluate Spreadsheet Guardian, we implemented a representative testing
technique as an add-in for Microsoft Excel.
  We evaluated the testing technique in two empirical evaluations with 29
end-users and 42 computer science students. The results indicate that the
technique is easy to learn and to apply. Furthermore, after finishing
maintenance, participants with spreadsheets "protected" by the technique are
more realistic about the correctness of their spreadsheets than participants
who employ only "classic", non-interactive test rules based on static analysis
techniques. Hence, we believe Spreadsheet Guardian can be of use for
business-critical spreadsheets.


title: Double Successive Rough Set Approximations

abstract:
  We examine double successive approximations on a set, which we denote by
$L_2L_1, \ U_2U_1, U_2L_1,$ $L_2U_1$ where $L_1, U_1$ and $L_2, U_2$ are based
on generally non-equivalent equivalence relations $E_1$ and $E_2$ respectively,
on a finite non-empty set $V.$ We consider the case of these operators being
given fully defined on its powerset $\mathscr{P}(V).$ Then, we investigate if
we can reconstruct the equivalence relations which they may be based on.
Directly related to this, is the question of whether there are unique solutions
for a given defined operator and the existence of conditions which may
characterise this. We find and prove these characterising conditions that
equivalence relation pairs should satisfy in order to generate unique such
operators.


title: Gradient-Based Multiobjective Optimization with Uncertainties

abstract:
  In this article we develop a gradient-based algorithm for the solution of
multiobjective optimization problems with uncertainties. To this end, an
additional condition is derived for the descent direction in order to account
for inaccuracies in the gradients and then incorporated in a subdivison
algorithm for the computation of global solutions to multiobjective
optimization problems. Convergence to a superset of the Pareto set is proved
and an upper bound for the maximal distance to the set of substationary points
is given. Besides the applicability to problems with uncertainties, the
algorithm is developed with the intention to use it in combination with model
order reduction techniques in order to efficiently solve PDE-constrained
multiobjective optimization problems.


title: $N$-player games and mean field games with absorption

abstract:
  We introduce a simple class of mean field games with absorbing boundary over
a finite time horizon. In the corresponding $N$-player games, the evolution of
players' states is described by a system of weakly interacting It\^o equations
with absorption on first exit from a bounded open set. Once a player exits,
her/his contribution is removed from the empirical measure of the system.
Players thus interact through a renormalized empirical measure. In the
definition of solution to the mean field game, the renormalization appears in
form of a conditional law. We justify our definition of solution in the usual
way, that is, by showing that a solution of the mean field game induces
approximate Nash equilibria for the $N$-player games with approximation error
tending to zero as $N$ tends to infinity. This convergence is established
provided the diffusion coefficient is non-degenerate. The degenerate case is
more delicate and gives rise to counter-examples.


title: Electronic structure of CuTeO$_4$ and its relationship to cuprates

abstract:
  Based on first principles calculations, the electronic structure of CuTeO$_4$
is discussed in the context of superconducting cuprates. Despite some
significant crystallographic differences, we find that CuTeO$_4$ is similar to
these cuprates, exhibiting a quasi two dimensional electronic structure that
involves hybridized Cu-$d$ and O-$p$ states in the vicinity of the Fermi level,
along with an antiferromagnetic insulating ground state. Hole doping this
material by substituting Te$^{6+}$ with Sb$^{5+}$ would be of significant
interest.


title:
A new hybrid code (CHIEF) implementing the inertial electron fluid
  equation without approximation

abstract:
  We present a new hybrid algorithm implemented in the code CHIEF (Code Hybrid
with Inertial Electron Fluid) for simulations of electron-ion plasmas. The
algorithm treats the ions kinetically, modeled by the Particle-in-Cell (PiC)
method, and electrons as an inertial fluid, modeled by electron fluid equations
without any of the approximations used in most of the other hybrid codes with
an inertial electron fluid. This kind of code is appropriate to model a large
variety of quasineutral plasma phenomena where the electron inertia and/or ion
kinetic effects are relevant. We present here the governing equations of the
model, how these are discretized and implemented numerically, as well as six
test problems to validate our numerical approach. Our chosen test problems,
where the electron inertia and ion kinetic effects play the essential role,
are: 0) Excitation of parallel eigenmodes to check numerical convergence and
stability, 1) parallel (to a background magnetic field) propagating
electromagnetic waves, 2) perpendicular propagating electrostatic waves (ion
Bernstein modes), 3) ion beam right-hand instability (resonant and
non-resonant), 4) ion Landau damping, 5) ion firehose instability, and 6) 2D
oblique ion firehose instability. Our results reproduce successfully the
predictions of linear and non-linear theory for all these problems, validating
our code. All properties of this hybrid code make it ideal to study multi-scale
phenomena between electron and ion scales such as collisionless shocks,
magnetic reconnection and kinetic plasma turbulence in the dissipation range
above the electron scales.


title:
Compact Gantry System for the Irradiation of Lying Patient by Proton/Ion
  beam

abstract:
  We describe here a compact gantry system, when the lying patient is slowly
moved in horizontal and vertical directions in accordance with rotation of
transport channel around its axis so that the region, irradiated from different
directions, stays in a focus of beam optical system. By this combination of
rotation of magnets and linear motion of patient it becomes possible to
simplify magnetic system significantly.


title: Weakly bound Li He$_2$ molecules

abstract:
  The results for binding energies of $^6$Li He$_2$ and $^7$Li He$_2$ systems
are presented. They are obtained by solving Faddeev equations in configuration
space. It is shown that the excited states in both systems are of the
Efimov-type.


title:
Population mixtures and searches of lensed and extended quasars across
  photometric surveys

abstract:
  Wide-field photometric surveys enable searches of rare yet interesting
objects, such as strongly lensed quasars or quasars with a bright host galaxy.
Past searches for lensed quasars based on their optical and near infrared
properties have relied on photometric cuts and spectroscopic pre-selection (as
in the Sloan Quasar Lens Search), or neural networks applied to photometric
samples. These methods rely on cuts in morphology and colours, with the risk of
losing many interesting objects due to scatter in their population properties,
restrictive training sets, systematic uncertainties in catalog-based
magnitudes, and survey-to-survey photometric variations. Here, we explore the
performance of a Gaussian Mixture Model to separate point-like quasars, quasars
with an extended host, and strongly lensed quasars using griz psf and model
magnitudes and WISE W1, W2. The choice of optical magnitudes is due to their
presence in all current and upcoming releases of wide-field surveys, whereas UV
information is not always available. We then assess the contamination from blue
galaxies and the role of additional features such as W3 magnitudes or psf-model
terms as morphological information. As a demonstration, we conduct a search in
a random 10% of the SDSS footprint, and we provide the catalog of the 43 SDSS
object with the highest `lens' score in our selection that survive visual
inspection, and are spectroscopically confirmed to host active nuclei. We
inspect archival data and find images of 5/43 objects in the Hubble Legacy
Archive, including 2 known lenses. The code and materials are available to
facilitate follow-up.


title: Cosmological perturbations in transient phantom inflation scenarios

abstract:
  We present a model of inflation where the inflaton is accommodated as a
phantom field which exhibits an initial transient pole behavior and then decays
into a quintessence field which is responsible for a radiation era. We must
stress that the present unified model only deals with a single field and that
the transition between two eras is achieved in a smooth way, so the model does
not suffer from the eternal inflation issue. We explore the conditions for the
crossing of the phantom divide line within the inflationary era along with the
structural stability of several critical points. We study the behavior of the
phantom field within the slow climb approximation along with the necessary
conditions to have sufficient inflation. We also examine the model at the level
of classical perturbations within the Newtonian gauge and determine the
behavior of the gravitational potential, contrast density and perturbed field
near the inflation stage and the subsequent radiation era.


title: An isoperimetric inequality for diffused surfaces

abstract:
  For general varifolds in Euclidean space, we prove an isoperimetric
inequality, adapt the basic theory of generalised weakly differentiable
functions, and obtain several Sobolev type inequalities. We thereby intend to
facilitate the use of varifold theory in the study of diffused surfaces.


title:
A note on existence of global solutions and invariant measures for jump
  SDEs with locally one-sided Lipschitz drift

abstract:
  We extend some methods developed by Albeverio, Brze\'{z}niak and Wu and we
show how to apply them in order to prove existence of global strong solutions
of stochastic differential equations with jumps, under a local one-sided
Lipschitz condition on the drift (also known as a monotonicity condition) and a
local Lipschitz condition on the diffusion and jump coefficients, while an
additional global one-sided linear growth assumption is satisfied. Then we use
these methods to prove existence of invariant measures for a broad class of
such equations.


title: Towards a new paradigm for quark-lepton unification

abstract:
  The quark and lepton mass patterns upset their naive unification. In this
paper, a new approach to solve this problem is proposed. Model-independently,
we find that a successful unification can be achieved. A mechanism is
identified by which the large top quark mass renders its third-generation
leptonic partner very light. This state is thus identified with the electron.
We then provide a generic dynamical implementation of this mechanism, using
tree-level exchanges of vector leptons to relate the quark and lepton flavor
structures. In a supersymmetric context, this same mechanism splits the squark
masses, and third generation squarks end up much lighter than the others.
Finally, the implementation of this mechanism in SU(5) GUT permits to avoid
introducing any flavor structure beyond the two minimal Yukawa couplings,
ensuring the absence of unknown mixing matrices and their potentially large
impact on FCNC.


title: On polynomial functions on non-conmmutative groups

abstract:
  Let $G$ be a topological group. We investigate relations between two classes
of "polynomial like" continuous functions on $G$ defined, respectively, by the
conditions (1) $\Delta_h^{n+1}f=0$ for every $h \in G$, and (2)
$\Delta_{h_{n+1}} \Delta_{h_{n}}\cdots \Delta_{h_{1}}f=0$, for every
$h_1,\cdots, h_{n+1} \in G$. It is shown that for many (but not all) groups
these classes coincide. We consider also Montel type versions of the above
conditions - when (1) and (2) hold only for steps $h$ in a generating subset of
$G$. Our approach is based on the study of the counterparts of the discussed
classes for general representations of groups (instead of the regular
representation).


title: New constraints on the 3-3-1 model with right-handed neutrinos

abstract:
  In the framework of a 3-3-1 model with right-handed neutrinos and three
scalar triplets we consider different spontaneous symmetry breaking patterns
seeking for a non-linear realization of accidental symmetries of the model,
which will produce physical Nambu-Goldstone (NG) bosons in the neutral scalar
spectrum. We make a detailed study of the safety of the model concerning the NG
boson emission in energy loss processes which could affect the standard
evolution of astrophysical objects. We consider the model with a $\mathbb{Z}_2$
symmetry, conventionally used in the literature, finding that in all of the
symmetry breaking patterns the model is excluded. Additionally, looking for
solutions for that problem, we introduce soft $\mathbb{Z}_2$-breaking terms in
the scalar potential in order to remove the extra accidental symmetries and at
the same time maintain the model as simple as possible. We find that there is
only one soft $\mathbb{Z}_2$-violating term that can get rid of the problematic
NG bosons.


title:
Rate-Equation Modelling and Ensemble Approach to Extraction of
  Parameters for Viral Infection-Induced Cell Apoptosis and Necrosis

abstract:
  We develop a theoretical approach that uses physiochemical kinetics modelling
to describe cell population dynamics upon progression of viral infection in
cell culture, which results in cell apoptosis (programmed cell death) and
necrosis (direct cell death). Several model parameters necessary for computer
simulation were determined by reviewing and analyzing available published
experimental data. By comparing experimental data to computer modelling
results, we identify the parameters that are the most sensitive to the measured
system properties and allow for the best data fitting. Our model allows
extraction of parameters from experimental data and also has predictive power.
Using the model we describe interesting time-dependent quantities that were not
directly measured in the experiment, and identify correlations among the fitted
parameter values. Numerical simulation of viral infection progression is done
by a rate-equation approach resulting in a system of "stiff" equations, which
are solved by using a novel variant of the stochastic ensemble modelling
approach. The latter was originally developed for coupled chemical reactions.

categories: q-bio.QM cond-mat.stat-mech physics.bio-ph q-bio.CB


title:
Effect of secondary electron emission on subnanosecond breakdown in
  high-voltage pulse discharge

abstract:
  A subnanosecond breakdown in high-voltage pulse discharge is studied in
experiment and in kinetic simulations for mid-high pressure in helium. It is
shown that the characteristic time of the current growth can be controlled by
the secondary electron emission. We test the influence of secondary electron
yield on plasma parameters for three types of cathodes made from titanium,
silicon carbide and CuAlMg-alloy. By changing the pulse voltage amplitude and
gas pressure, the area of existence of subnanosecond breakdown is identified.


title:
Intermediate extensions of perverse constructible $\mathbb{F}_p$-sheaves
  commute with smooth pullbacks

abstract:
  We prove that intermediate extensions of perverse constructible
$\mathbb{F}_p$-sheaves commute with smooth pullbacks for schemes admitting a
closed embedding into a smooth scheme over a field of characteristic $p$
(embeddable schemes for short). Along the way we also prove that the
equivalence of categories of Cartier crystals with unit $R[F]$-modules commutes
with $f^!$ for a smooth morphism $f: X \to Y$ of embeddable schemes.


title:
Constant Step Stochastic Approximations Involving Differential
  Inclusions: Stability, Long-Run Convergence and Applications

abstract:
  We consider a Markov chain $(x_n)$ whose kernel is indexed by a scaling
parameter $\gamma>0$, refered to as the step size. The aim is to analyze the
behavior of the Markov chain in the doubly asymptotic regime where $n\to\infty$
then $\gamma\to 0$. First, under mild assumptions on the so-called drift of the
Markov chain, we show that the interpolated process converges narrowly to the
solutions of a Differential Inclusion (DI) involving an upper semicontinuous
set-valued map with closed and convex values. Second, we provide verifiable
conditions which ensure the stability of the iterates. Third, by putting the
above results together, we establish the long run convergence of the iterates
as $\gamma\to 0$, to the Birkhoff center of the DI. The ergodic behavior of the
iterates is also provided. Application examples are investigated. We apply our
findings to 1) the problem of nonconvex proximal stochastic optimization and 2)
a fluid model of parallel queues.


title: A characterisation of toric LCK manifolds

abstract:
  We prove that a compact toric locally conformally K\"ahler manifold which is
not K\"ahler admits a toric Vaisman structure, a fact which was conjectured in
\cite{mmp}. This is the final step leading to the classification of compact
toric locally conformally K\"ahler manifolds started in \cite{p} and
\cite{mmp}. We also show, by constructing an example, that unlike in the
symplectic case, toric locally conformally symplectic manifolds are not
necessarily toric locally conformally K\"ahler.


title:
Determination of a high spatial resolution geopotential model using
  atomic clock comparisons

abstract:
  Recent technological advances in optical atomic clocks are opening new
perspectives for the direct determination of geopotential differences between
any two points at a centimeter-level accuracy in geoid height. However, so far
detailed quantitative estimates of the possible improvement in geoid
determination when adding such clock measurements to existing data are lacking.
We present a first step in that direction with the aim and hope of triggering
further work and efforts in this emerging field of chronometric geodesy and
geophysics. We specifically focus on evaluating the contribution of this new
kind of direct measurements in determining the geopotential at high spatial
resolution (~ 10 km). We studied two test areas, both located in France and
corresponding to a middle (Massif Central) and high (Alps) mountainous terrain.
These regions are interesting because the gravitational field strength varies
greatly from place to place at high spatial resolution due to the complex
topography. Our method consists in first generating a synthetic high resolution
geopotential map, then drawing synthetic measurement data (gravimetry and clock
data) from it, and finally reconstructing the geopotential map from that data
using least squares collocation. The quality of the reconstructed map is then
assessed by comparing it to the original one used to generate the data. We show
that adding only a few clock data points (less than 1 % of the gravimetry data)
reduces the bias significantly and improves the standard deviation by a factor
3. The effect of the data coverage and data quality on the results is
investigated, and the trade-off between the measurement noise level and the
number of data points is discussed.


title: Evolutionary Dynamics of Group Formation

abstract:
  We introduce a model, based on the Evolutionary Game Theory, for studying the
dynamics of group formation. The latter constitutes a relevant phenomenon
observed in different animal species, whose individuals tend to cluster
together forming groups of different size. Results of previous investigations
suggest that this phenomenon might have similar reasons across different
species, such as improving the individual safety (e.g. from predators), and
increasing the probability to get food resources. Remarkably, the group size
might strongly vary from species to species, and sometimes even within the same
species. In the proposed model, an agent population tries to form homogeneous
groups. The homogeneity of a group is computed according to a spin vector, that
characterizes each agent, and represents a set a features (e.g. physical
traits). We analyze the formation of groups of different size, on varying a
parameter named 'individual payoff'. The latter represents the gain one agent
would receive acting individually. In particular, the agents choose whether to
form a group (receiving a 'group payoff'), or if to play individually
(receiving an 'individual payoff'). The phase diagram representing the
equilibria of our population shows a sharp transition between the 'group phase'
and the 'individual phase', in correspondence of a critical 'individual
payoff'. In addition, we found that forming (homogeneous) small groups is
easier than forming big groups. To conclude, we deem that our model and the
related results supports the hypothesis that the phenomenon of group formation
has evolutionary roots.


title: Random lasing in an Anderson localizing optical fiber

abstract:
  A directional random laser mediated by transverse Anderson localization in a
disordered glass optical fiber is reported. Previous demonstrations of random
lasers have found limited applications because of their multi-directionality
and chaotic fluctuations in the laser emission. The random laser presented in
this paper operates in the Anderson localization regime. The disorder induced
localized states form isolated local channels that make the output laser beam
highly directional and stabilize its spectrum. The strong transverse disorder
and longitudinal invariance result in isolated lasing modes with negligible
interaction with their surroundings, traveling back and forth in a Fabry-Perot
cavity formed by the air-fiber interfaces. It is shown that if a localized
input pump is scanned across the disordered fiber input facet, the output laser
signal follows the transverse position of the pump. Moreover, a uniformly
distributed pump across the input facet of the disordered fiber generates a
laser signal with very low spatial coherence that can be of practical
importance in many optical platforms including image transport with fiber
bundles.


title:
Dark matter constraints from an observation of dSphs and the LMC with
  the Baikal NT200

abstract:
  In present analysis we complete search for a dark matter signal with the
Baikal neutrino telescope NT200 from potential sources in the sky. We use five
years of data and look for neutrinos from dark matter annihilations in the
dwarfs spheroidal galaxies in the Southern hemisphere and the Large Magellanic
Cloud known as the largest and close satellite galaxy of the Milky Way. We do
not find any excess in observed data over expected background from the
atmospheric neutrinos towards the LMC or any of tested 22 dwarfs. We perform a
joint likelihood analysis on the sample of five selected dwarfs and found a
concordance of the data with null hypothesis of the background-only
observation. We derive 90% CL upper limits on the cross section of annihilating
dark matter particles of mass between 30 GeV and 10 TeV into several channels
both in our combined analysis of the dwarfs and in a particular analysis
towards the LMC.


title: On H-Spaces and a Congruence of Catalan Numbers

abstract:
  For $p$ an odd prime and $F$ the cyclic group of order $p$, we show that the
number of conjugacy classes of embeddings of $F$ in $SU(p)$ such that no
element of $F$ has 1 as an eigenvalue is $(1+C_{p-1})/p$, where $C_{p-1}$ is a
Catalan number. We prove that the only coset space $SU(p)/F$ that admits a
$p$-local $H$-structure is the classical Lie group $PSU(p)$. We also show that
$SU(4)/\mathbb Z_3$, where $\mathbb Z_3$ is embedded off the center of $SU(4)$,
is a novel example of an $H$-space, even globally. We apply our results to the
study of homotopy classes of maps from $BF$ to $BSU(n)$.


title: Toric degenerations of Gr(2,n) and Gr(3,6) via plabic graphs

abstract:
  We establish an explicit bijection between the toric degenerations of the
Grassmannian $\textrm{Gr}(2,n)$ arising from maximal cones in tropical
Grassmannians and the ones coming from plabic graphs corresponding to
$\textrm{Gr}(2,n)$. We show that a similar statement does not hold for
$\textrm{Gr}(3,6)$.


title: Tensor Decompositions via Two-Mode Higher-Order SVD (HOSVD)

abstract:
  Tensor decompositions have rich applications in statistics and machine
learning, and developing efficient, accurate algorithms for the problem has
received much attention recently. Here, we present a new method built on
Kruskal's uniqueness theorem to decompose symmetric, nearly orthogonally
decomposable tensors. Unlike the classical higher-order singular value
decomposition which unfolds a tensor along a single mode, we consider
unfoldings along two modes and use rank-1 constraints to characterize the
underlying components. This tensor decomposition method provably handles a
greater level of noise compared to previous methods and achieves a high
estimation accuracy. Numerical results demonstrate that our algorithm is robust
to various noise distributions and that it performs especially favorably as the
order increases.


title: Revisiting the O(3) Non-linear Sigma Model and Its Pohlmeyer Reduction

abstract:
  It is well known that sigma models in symmetric spaces accept equivalent
descriptions in terms of integrable systems such as the sine-Gordon equation
through Pohlmeyer reduction. In this paper, we study the mapping between known
solutions of the Euclidean O(3) non-linear sigma model, such as instantons,
merons and elliptic solutions that interpolate between the latter and solutions
of the Pohlmeyer reduced theory, namely the sinh-Gordon equation. It turns out
that instantons do not have a counterpart, merons correspond to the ground
state, while the class of elliptic solutions is characterized by a two to one
correspondence between solutions in the two descriptions.


title:
Locally Recoverable Codes with Availability $t\geq 2$ from Fiber
  Products of Curves

abstract:
  We generalize the construction of locally recoverable codes on algebraic
curves given by Barg, Tamo and Vl\u{a}du\c{t} to those with arbitrarily many
recovery sets by exploiting the structure of fiber products of curves.
Employing maximal curves, we create several new families of locally recoverable
codes with multiple recovery sets, including codes with two recovery sets from
the generalized Giulietti and Korchm\'{a}ros (GK) curves and the Suzuki curves,
and new locally recoverable codes with many recovery sets based on the
Hermitian curve, using a fiber product construction of van der Geer and van der
Vlugt. In addition, we consider the relationship between local error recovery
and global error correction as well as the availability required to locally
recover any pattern of a fixed number of erasures.


title: Weakly bound molecules as sensors of new gravitylike forces

abstract:
  Several extensions to the Standard Model of particle physics, including light
dark matter candidates and unification theories, predict deviations from
Newton's law of gravitation. For macroscopic distances, the inverse-square law
of gravitation is well confirmed by astrophysical observations and laboratory
experiments. At micrometer and shorter length scales, however, even the
state-of-the-art constraints on deviations from gravitational interaction,
whether provided by neutron scattering or precise measurements of forces
between macroscopic bodies, are currently many orders of magnitude larger than
gravity itself. Here we show that precision spectroscopy of weakly bound
molecules can be used to constrain non-Newtonian interactions between atoms. A
proof-of-principle demonstration using recent data from photoassociation
spectroscopy of weakly bound Yb$_2$ molecules yields constraints on these new
interactions that are already close to state-of-the-art neutron scattering
experiments. At the same time, with the development of the recently proposed
optical molecular clocks, the neutron scattering constraints could be surpassed
by at least two orders of magnitude.


title: Multiplicity free quasi-Hamiltonian manifolds

abstract:
  A (quasi-)Hamiltonian manifold is called multiplicity free if all of its
symplectic reductions are 0-dimensional. In this paper, we classify
multiplicity free Hamiltonian actions for (twisted) loop groups or,
equivalently, multiplicity free (twisted) quasi-Hamiltonian manifolds for
simply connected compact Lie groups. As a result we recover old and find new
examples of these structures.


title: How far are Extraterrestrial Life and Intelligence after Kepler ?

abstract:
  The Kepler mission has shown that a significant fraction of all stars may
have an Earth-size habitable planet. A dramatic support was the recent
detection of Proxima Centauri b. Using a Drake-equation like formalism I derive
an equation for the abundance of biotic planets as a function of the relatively
modest uncertainty in the astronomical data and of the (yet unknown)
probability for the evolution of biotic life, Fb. I suggest that Fb may be
estimated by future spectral observations of exoplanet biomarkers. It follows
that if Fb is not very small, then a biotic planet may be expected within about
10 light years from Earth. Extending this analyses to advanced life, I derive
expressions for the distance to putative civilizations in terms of two
additional Drake parameters - the probability for evolution of a civilization,
Fc, and its average longevity. Assuming "optimistic" values for the Drake
parameters, (Fb~Fc~1), and a broadcasting duration of a few thousand years, the
likely distance to the nearest civilizations detectable by SETI is of the order
of a few thousand light years. Finally I calculate the distance and probability
of detecting intelligent signals with present and future radio telescopes such
as Arecibo and SKA and how it could constrain the Drake parameters.


title: A functional renormalization method for wave propagation in random media

abstract:
  We develop the exact renormalization group approach as a way to evaluate the
effective speed of propagation of a scalar wave in a medium with random
inhomogeneities. We use the Martin-Siggia-Rose formalism to translate the
problem into a non equilibrium field theory one, and then consider a sequence
of models with a progressively lower infrared cutoff; in the limit where the
cutoff is removed we recover the problem of interest. As a test of the
formalism, we compute the effective dielectric constant of an homogeneous
medium interspersed with randomly located, interpenetrating bubbles. Already a
simple approximation to the renormalization group equations turns out to be
equivalent to a self-consistent two-loops evaluation of the effective
dielectric constant.


title:
Simultaneous concentration and velocity maps in particle suspensions
  under shear from rheo-ultrasonic imaging

abstract:
  We extend a previously developed ultrafast ultrasonic technique [Gallot et
al., Rev. Sci. Instrum. 84, 045107 (2013)] to concentration field measurements
in non-Brownian particle suspensions under shear. The technique provides access
to time-resolved concentration maps within the gap of a Taylor-Couette cell
simultaneously to local velocity measurements and standard rheological
characterization. Benchmark experiments in homogeneous particle suspensions are
used to calibrate the system. We then image heterogeneous concentration fields
that result from centrifugation effects, from the classical Taylor-Couette
instability and from sedimentation or shear-induced resuspension.


title: Exact solitonic and periodic solutions of the extended KdV equation

abstract:
  The KdV equation can be derived in the shallow water limit of the Euler
equations. Over the last few decades, this equation has been extended to
include both higher order effects (KdV2) and an uneven river bottom. Although
this equation is not integrable and has only one conservation law, exact
periodic and solitonic solutions exist for the even bottom case. The method
used to find them assumes the same function forms as for KdV solutions. KdV2
equation imposes more constraints on parameters of solutions. For soliton case
KdV2 solution occurs for particular ratio of wave amplitude to water depth
only. For periodic case physically relevant solutions are admissible only for
two narrow intervals of elliptic parameter $m$. For a range of $m$ near one the
cnoidal waves are upright as expected, but are inverted in $m$ region close to
zero. Properties of exact solutions of KdV and KdV2 are compared.


title:
Computation of the asymptotic states of modulated open quantum systems
  with a numerically exact realization of the quantum trajectory method

abstract:
  Quantum systems out of equilibrium are presently a subject of active
research, both in theoretical and experimental domains. In this work we
consider time-periodically modulated quantum systems which are in contact with
a stationary environment. Within the framework of a quantum master equation,
the asymptotic states of such systems are described by time-periodic density
operators. Resolution of these operators constitutes a non-trivial
computational task. To go beyond the current size limits, we use the quantum
trajectory method which unravels master equation for the density operator into
a set of stochastic processes for wave functions. The asymptotic density matrix
is calculated by performing a statistical sampling over the ensemble of quantum
trajectories, preceded by a long transient propagation. We follow the ideology
of event-driven programming and construct a new algorithmic realization of the
method. The algorithm is computationally efficient, allowing for long 'leaps'
forward in time, and is numerically exact in the sense that, being given the
list of uniformly distributed (on the unit interval) random numbers, $\{\eta_1,
\eta_2,...,\eta_n\}$, one could propagate a quantum trajectory (with $\eta_i$'s
as norm thresholds) in a numerically exact way. %Since the quantum trajectory
method falls into the class of standard sampling problems, performance of the
algorithm %can be substantially improved by implementing it on a computer
cluster. By using a scalable $N$-particle quantum model, we demonstrate that
the algorithm allows us to resolve the asymptotic density operator of the model
system with $N = 2000$ states on a regular-size computer cluster, thus reaching
the scale on which numerical studies of modulated Hamiltonian systems are
currently performed.


title:
Distributed and Proximity-Constrained C-Means for Discrete Coverage
  Control

abstract:
  In this paper we present a novel distributed coverage control framework for a
network of mobile agents, in charge of covering a finite set of points of
interest (PoI), such as people in danger, geographically dispersed equipment or
environmental landmarks. The proposed algorithm is inspired by C-Means, an
unsupervised learning algorithm originally proposed for non-exclusive
clustering and for identification of cluster centroids from a set of
observations. To cope with the agents' limited sensing range and avoid
infeasible coverage solutions, traditional C-Means needs to be enhanced with
proximity constraints, ensuring that each agent takes into account only
neighboring PoIs. The proposed coverage control framework provides useful
information concerning the ranking or importance of the different PoIs to the
agents, which can be exploited in further application-dependent data fusion
processes, patrolling, or disaster relief applications.


title:
Transport spectroscopy of singlet-triplet quantum dot states coupled to
  electronic cavities

abstract:
  A strong coupling between an electronic cavity and a quantum dot has been
recently demonstrated [Phys. Rev. Lett. 115, 166603 (2015)] and described in a
comprehensive theoretical framework [Phys. Rev. B 96, 235431 (2017)]. Here, we
focus on the signatures that demonstrate the cavity's impact on inelastic
singlet-triplet transport through the dot. We find the same transport
signatures in the experiment as predicted by the model that describes the
coupled dot--cavity system. Interestingly, a lowest-order treatement of the
coupling to the electronic leads on top of an exact diagonalisation of the
dot-cavity system is sufficient to highlight the interplay between the cavity
and the higher-order inelastic singlet-triplet cotunneling.


title: A Supersymmetric SYK-like Tensor Model

abstract:
  We consider a supersymmetric SYK-like model without quenched disorder that is
built by coupling two kinds of fermionic N=1 tensor-valued superfields,
"quarks" and "mesons". We prove that the model has a well-defined large-N limit
in which the (s)quark 2-point functions are dominated by mesonic "melon"
diagrams. We sum these diagrams to obtain the Schwinger-Dyson equations and
show that in the IR, the solution agrees with that of the supersymmetric SYK
model.


title:
Smart Scheduling of Continuous Data-Intensive Workflows with Machine
  Learning Triggered Execution

abstract:
  To extract value from evergrowing volumes of data, coming from a number of
different sources, and to drive decision making, organizations frequently
resort to the composition of data processing workflows, since they are
expressive, flexible, and scalable. The typical workflow model enforces strict
temporal synchronization across processing steps without accounting the actual
effect of intermediate computations on the final workflow output. However, this
is not the most desirable behavior in a multitude of scenarios. We identify a
class of applications for continuous data processing where workflow output
changes slowly and without great significance in a short-to-medium time window,
thus wasting compute resources and energy with current approaches.
  To overcome such inefficiency, we introduce a novel workflow model, for
continuous and data-intensive processing, capable of relaxing triggering
semantics according to the impact input data is assessed to have on changing
the workflow output. To assess this impact, learn the correlation between input
and output variation, and guarantee correctness within a given tolerated error
constant, we rely on Machine Learning. The functionality of this workflow model
is implemented in SmartFlux, a middleware framework which can be effortlessly
integrated with existing workflow managers. Experimental results indicate we
are able to save a significant amount of resources while not deviating the
workflow output beyond a small error constant with high confidence level.


title: The rumor percolation model and its variations

abstract:
  The study of rumor models from a percolation theory point of view has gained
a few adepts in the last few years. The persistence of a rumor, which may
consistently spread out throughout a population can be associated to the
existence of a giant component containing the origin of a graph. That is one of
the main interest in percolation theory. In this paper we present a quick
review of recent results on rumor models of this type.


title: Crossing Number for Graphs With Bounded Pathwidth

abstract:
  The crossing number is the smallest number of pairwise edge-crossings when
drawing a graph into the plane. There are only very few graph classes for which
the exact crossing number is known or for which there at least exist constant
approximation ratios. Furthermore, up to now, general crossing number
computations have never been successfully tackled using bounded width of graph
decompositions, like treewidth or pathwidth.
  In this paper, we for the first time show that crossing number is tractable
(even in linear time) for maximal graphs of bounded pathwidth~3. The technique
also shows that the crossing number and the rectilinear (a.k.a. straight-line)
crossing number are identical for this graph class, and that we require only an
$O(n)\times O(n)$-grid to achieve such a drawing.
  Our techniques can further be extended to devise a 2-approximation for
general graphs with pathwidth 3, and a $4w^3$-approximation for maximal graphs
of pathwidth $w$. This is a constant approximation for bounded pathwidth
graphs.


title: Quantum Hall Effect on Odd Spheres

abstract:
  We solve the Landau problem for charged particles on odd-dimensional spheres
$S^{2k-1}$ in the background of constant SO(2k-1) gauge fields carrying the
irreducible representation $\left ( \frac{I}{2}, \frac{I}{2}, \cdots,
\frac{I}{2} \right)$. We determine the spectrum of the Hamiltonian, the
degeneracy of the Landau levels and give the eigenstates in terms of the Wigner
${\cal D}$-functions, and for odd values of $I$ the explicit local form of the
wave functions in the lowest Landau level (LLL). Spectrum of the Dirac operator
on $S^{2k-1}$ in the same gauge field background together with its degeneracies
is also determined and in particular the number of zero modes is found. We show
how the essential differential geometric structure of the Landau problem on the
equatorial $S^{2k-2}$ is captured by constructing the relevant projective
modules. For the Landau problem on $S^5$, we demonstrate an exact
correspondence between the union of Hilbert spaces of LLL's with $I$ ranging
from $0$ to $I_{max} = 2K$ or $I_{max} = 2K+1$ to the Hilbert spaces of the
fuzzy ${\mathbb C}P^3$ or that of winding number $\pm1$ line bundles over
${\mathbb C}P^3$ at level $K$, respectively.


title:
Improved Algorithms for Decremental Single-Source Reachability on
  Directed Graphs

abstract:
  Recently we presented the first algorithm for maintaining the set of nodes
reachable from a source node in a directed graph that is modified by edge
deletions with $o(mn)$ total update time, where $m$ is the number of edges and
$n$ is the number of nodes in the graph [Henzinger et al. STOC 2014]. The
algorithm is a combination of several different algorithms, each for a
different $m$ vs. $n$ trade-off. For the case of $m = \Theta(n^{1.5})$ the
running time is $O(n^{2.47})$, just barely below $mn = \Theta(n^{2.5})$. In
this paper we simplify the previous algorithm using new algorithmic ideas and
achieve an improved running time of $\tilde O(\min(m^{7/6} n^{2/3}, m^{3/4}
n^{5/4 + o(1)}, m^{2/3} n^{4/3+o(1)} + m^{3/7} n^{12/7+o(1)}))$. This gives,
e.g., $O(n^{2.36})$ for the notorious case $m = \Theta(n^{1.5})$. We obtain the
same upper bounds for the problem of maintaining the strongly connected
components of a directed graph undergoing edge deletions. Our algorithms are
correct with high probabililty against an oblivious adversary.


title:
Operator equations $AX+YB=C$ and $AXA^*+BYB^*=C$ in Hilbert
  $C^*$-modules

abstract:
  Let $A,B$ and $C$ be adjointable operators on a Hilbert $C^*$-module
$\mathscr{E}$. Giving a suitable version of the celebrated Douglas theorem in
the context of Hilbert $C^*$-modules, we present the general solution of the
equation $AX+YB=C$ when the ranges of $A,B$ and $C$ are not necessarily closed.
We examine a result of Fillmore and Williams in the setting of Hilbert
$C^*$-modules. Moreover, we obtain some necessary and sufficient conditions for
existence of a solution for $AXA^*+BYB^*=C$. Finally, we deduce that there
exist nonzero operators $X, Y\geq 0$ and $Z$ such that $AXA^*+BYB^*=CZ$, when
$A, B$ and $C$ are given subject to some conditions.


title: Frequency Coverage Properties of a Uniform Shrinkage Prior Distribution

abstract:
  A uniform shrinkage prior (USP) distribution on the unknown variance
component of a random-effects model is known to produce good frequency
properties. The USP has a parameter that determines the shape of its density
function, but it has been neglected whether the USP can maintain such good
frequency properties regardless of the choice for the shape parameter. We
investigate which choice for the shape parameter of the USP produces Bayesian
interval estimates of random effects that meet their nominal confidence levels
better than several existent choices in the literature. Using univariate and
multivariate Gaussian hierarchical models, we empirically show that the USP can
achieve its best frequency properties when its shape parameter makes the USP
behave similarly to an improper flat prior distribution on the unknown variance
component.


title:
Modeling the Effect of Blunt Impact on Mitochondrial Dysfunction in
  Cartilage

abstract:
  Mounting evidence for the role of oxidative stress in the degeneration of
articular cartilage after an injurious impact requires our modeling &
simulation efforts to temporarily shift from just describing the effect of
mechanical stress and inflammation on osteoarthritis (OA). The hypothesis that
the injurious impact causes irreversible damage to chondrocyte mitochondria,
which in turn increase their production of free radicals, affecting their
energy production and their ability to rebuild the extracellular matrix, has to
be modeled and the processes quantified in order to further the understanding
of OA, its causes, and viable treatment options. The current article presents a
calibrated model that captures the damage oxidative stress incurs on the cell
viability, ATP production, and cartilage stability in a cartilage explant after
a drop-tower impact. The model validates the biological hypothesis and will be
used in further efforts to identify possibilities for treatment and be a part
of a bigger modeling & simulation framework for the development of OA.


title: Neutrino Signatures From Young Neutron Stars

abstract:
  After a successful core collapse supernova (CCSN) explosion, a hot dense
proto-neutron star (PNS) is left as a remnant. Over a time of twenty or so
seconds, this PNS emits the majority of the neutrinos that come from the CCSN,
contracts, and loses most of its lepton number. This is the process by which
all neutron stars in our galaxy are likely born. The emitted neutrinos were
detected from SN 1987A and they will be detected in much greater numbers from
any future galactic CCSN. These detections can provide a direct window into the
properties of the dense matter encountered inside neutron stars, and they can
affect nucleosynthesis in the mate- rial ejected during the CCSN. In this
chapter, we review the basic physics of PNS cooling, including the basic
equations of PNS structure and neutrino diffusion in dense matter. We then
discuss how the nuclear equation of state, neutrino opacities in dense matter,
and convection can shape the temporal behavior of the neutrino signal. We also
discuss what was learned from the late time SN 1987A neutrinos, the prospects
for detection of these neutrinos from future galactic CCSNe, and the effects
these neutrinos can have on nucleosynthesis.


title:
Newton-Okounkov bodies and Toric Degenerations of Mori dream spaces via
  Tropical compactifications

abstract:
  Given a smooth Mori dream space $X$ we construct a model dominating all the
small $\mathbb{Q}$-factorial modifications via tropicalization. This
construction allows us to recover a Minkowski basis for the Newton-Okounkov
bodies of divisors on $X$ and hence the movable cone of $X$. The existence of
such basis allows us to prove the polyhedrality of the global Newton-Okounkov
body and the existence of toric degenerations.


abstract:
  We prove the existence of Sullivan minimal models of operad algebras, for a
quite wide family of operads in the category of complexes of vector spaces over
a field of characteristic zero. Our construction is an adaptation of Sullivan's
original step by step construction to the setting of operad algebras. The
family of operads that we consider includes all operads concentrated in degree
0 as well as their minimal models. In particular, this gives Sullivan minimal
models for algebras over Com, Ass and Lie, as well as over their minimal
models. Other interesting operads, such as the operad Ger encoding Gerstenhaber
algebras, also fit in our study.


title: Output-Feedback Stabilization for a Class of Linear Parabolic Systems

abstract:
  We consider output-feedback stabilization problems for a class of
two-component linear parabolic systems with boundary actuation and measurement.
The state-feedback control laws are obtained using backstepping method and
require measurement of the state at each point in the domain. To this end,
backstepping observers are designed for both anti-collocated and collocated
sensors and actuators. Furthermore, we show the closed-loop systems consisting
of the plant, the backstepping control laws, and the observer is exponentially
stable. The backstepping method is used to obtain both control and observer
kernels. The kernels are the solution of $4\times4$ systems of second-order
hyperbolic linear PDEs whose well-posedness is shown.


title: Effector Detection in Social Networks

abstract:
  In a social network, influence diffusion is the process of spreading
innovations from user to user. An activation state identifies who are the
active users who have adopted the target innovation. Given an activation state
of a certain diffusion, effector detection aims to reveal the active users who
are able to best explain the observed state. In this paper, we tackle the
effector detection problem from two perspectives. The first approach is based
on the influence distance that measures the chance that an active user can
activate its neighbors. For a certain pair of users, the shorter the influence
distance, the higher probability that one can activate the other. Given an
activation state, the effectors are expected to have short influence distance
to active users while long to inactive users. By this idea, we propose the
influence-distance-based effector detection problem and provide a
3-approximation. Second, we address the effector detection problem by the
maximum likelihood estimation (MLE) approach. We prove that the optimal MLE can
be obtained in polynomial time for connected directed acyclic graphs. For
general graphs, we first extract a directed acyclic subgraph that can well
preserve the information in the original graph and then apply the MLE approach
to the extracted subgraph to obtain the effectors. The effectiveness of our
algorithms is experimentally verified via simulations on the real-world social
network.


title:
Spectral and timing properties of IGR J00291+5934 during its 2015
  outburst

abstract:
  We report on the spectral and timing properties of the accreting millisecond
X-ray pulsar IGR J00291+5934 observed by XMM-Newton and NuSTAR during its 2015
outburst. The source is in a hard state dominated at high energies by a
comptonization of soft photons ($\sim0.9$ keV) by an electron population with
kT$_e\sim30$ keV, and at lower energies by a blackbody component with
kT$\sim0.5$ keV. A moderately broad, neutral Fe emission line and four narrow
absorption lines are also found. By investigating the pulse phase evolution, we
derived the best-fitting orbital solution for the 2015 outburst. Comparing the
updated ephemeris with those of the previous outbursts, we set a $3\sigma$
confidence level interval $-6.6\times 10^{-13}$ s/s $< \dot{P}_{orb} < 6.5
\times 10^{-13}$ s/s on the orbital period derivative. Moreover, we
investigated the pulse profile dependence on energy finding a peculiar
behaviour of the pulse fractional amplitude and lags as a function of energy.
We performed a phase-resolved spectroscopy showing that the blackbody component
tracks remarkably well the pulse-profile, indicating that this component
resides at the neutron star surface (hot-spot).


title: Quantizations of D=3 Lorentz symmetry

abstract:
  Using the isomorphism
$\mathfrak{o}(3;\mathbb{C})\simeq\mathfrak{sl}(2;\mathbb{C})$ we develop a new
simple algebraic technique for complete classification of quantum deformations
(the classical $r$-matrices) for real forms $\mathfrak{o}(3)$ and
$\mathfrak{o}(2,1)$ of the complex Lie algebra $\mathfrak{o}(3;\mathbb{C})$ in
terms of real forms of $\mathfrak{sl}(2;\mathbb{C})$: $\mathfrak{su}(2)$,
$\mathfrak{su}(1,1)$ and $\mathfrak{sl}(2;\mathbb{R})$. We prove that the $D=3$
Lorentz symmetry
$\mathfrak{o}(2,1)\simeq\mathfrak{su}(1,1)\simeq\mathfrak{sl}(2;\mathbb{R})$
has three different Hopf-algebraic quantum deformations which are expressed in
the simplest way by two standard $\mathfrak{su}(1,1)$ and
$\mathfrak{sl}(2;\mathbb{R})$ $q$-analogs and by simple Jordanian
$\mathfrak{sl}(2;\mathbb{R})$ twist deformations. These quantizations are
presented in terms of the quantum Cartan-Weyl generators for the quantized
algebras $\mathfrak{su}(1,1)$ and $\mathfrak{sl}(2;\mathbb{R})$ as well as in
terms of quantum Cartesian generators for the quantized algebra
$\mathfrak{o}(2,1)$. Finaly, some applications of the deformed $D=3$ Lorentz
symmetry are mentioned.


title:
Output Feedback Stabilization of Semilinear Parabolic PDEs using
  Backstepping

abstract:
  In this paper, we present output feedback boundary stabilization for a class
of semilinear parabolic PDEs with a boundary measurement and an actuation
located at the same place. The method uses backstepping transformations, where
the state and error systems are proved to be locally exponentially stable in
the $\mathbb{H}^4$ norm. The stability of the transformed systems are obtained
by constructing a strict Lyapunov function. A numerical example using the
FitzHugh-Nagumo equation shows the proposed control law stabilizes the system
into its equilibrium solution.


title: Random Kneser graphs and hypergraphs

abstract:
  The Kneser graph $KG_{n,k}$ is the graph whose vertices are the $k$-element
subsets of $[n],$ with two vertices adjacent if and only if the corresponding
sets are disjoint. A famous result due to Lov\'asz states that the chromatic
number of $KG_{n,k}$ is equal to $n-2k+2$. In this paper we discuss the
chromatic number of random Kneser graphs and hypergraphs. It was studied in two
recent papers, one due to Kupavskii, who proposed the problem and studied the
graph case, and the more recent one due to Alishahi and Hajiabolhassan. The
authors of the latter paper had extended the result of Kupavskii to the case of
general Kneser hypergraphs. Moreover, they have improved the bounds of
Kupavskii in the graph case for many values of parameters.
  In the present paper we present a purely combinatorial approach to the
problem based on blow-ups of graphs, which gives much better bounds on the
chromatic number of random Kneser and Schrijver graphs and Kneser hypergraphs.
This allows us to improve all known results on the topic. The most interesting
improvements are obtained in the case of $r$-uniform Kneser hypergraphs with
$r\ge 3$, where we managed to replace certain polynomial dependencies of the
parameters by the logarithmic ones.


title:
Deterministic generation of all-photonic quantum repeaters from
  solid-state emitters

abstract:
  Quantum repeaters are nodes in a quantum communication network that allow
reliable transmission of entanglement over large distances. It was recently
shown that highly entangled photons in so-called graph states can be used for
all-photonic quantum repeaters, which require substantially fewer resources
compared to atomic-memory based repeaters. However, standard approaches to
building multi-photon entangled states through pairwise probabilistic
entanglement generation severely limit the size of the state that can be
created. Here, we present a protocol for the deterministic generation of large
photonic repeater states using quantum emitters such as semiconductor quantum
dots and defect centers in solids. We show that arbitrarily large repeater
states can be generated using only two coupled emitters, reducing the necessary
number of photon sources by six orders of magnitude. Our protocol includes a
built-in redundancy which makes it resilient to photon loss.


title: Estimating individual employment status using mobile phone network data

abstract:
  This study provides the first confirmation that individual employment status
can be predicted from standard mobile phone network logs externally validated
with household survey data. Individual welfare and households vulnerability to
shocks are intimately connected to employment status and professions of
household breadwinners. At a societal level unemployment is an important
indicator of the performance of an economy. By deriving a broad set of novel
mobile phone network indicators reflecting users financial, social and mobility
patterns we show how machine learning models can be used to predict 18
categories of profession in a South-Asian developing country. The model
predicts individual unemployment status with 70.4 percent accuracy. We further
show how unemployment can be aggregated from individual level and mapped
geographically at cell tower resolution, providing a promising approach to map
labor market economic indicators, and the distribution of economic productivity
and vulnerability between censuses, especially in heterogeneous urban areas.
The method also provides a promising approach to support data collection on
vulnerable populations, which are frequently under-represented in official
surveys.