title:
Possible Nematic Spin Liquid in Spin-$1$ Antiferromagnetic System on the
  Square Lattice: Implication for the Nematic Paramagnetic State of FeSe

abstract:
  The exotic normal state of iron chalcogenide superconductor FeSe, which
exhibits vanishing magnetic order and possesses an electronic nematic order,
triggered extensive explorations of its magnetic ground state. To understand
its novel properties, we study the ground state of a highly frustrated spin-$1$
system with bilinear-biquadratic interactions using unbiased large-scale
density matrix renormalization group. Remarkably, with increasing biquadratic
interactions, we find a paramagnetic phase between N\'eel and stripe magnetic
ordered phases. We identify this phase as a candidate of nematic quantum spin
liquid by the compelling evidences, including vanished spin and quadrupolar
orders, absence of lattice translational symmetry breaking, and a persistent
non-zero lattice nematic order in the thermodynamic limit. The established
quantum phase diagram natually explains the observations of enhanced spin
fluctuations of FeSe in neutron scattering measurement and the phase transition
with increasing pressure. This identified paramagnetic phase provides a new
possibility to understand the novel properties of FeSe.


title: Cluster-tilted and quasi-tilted algebras

abstract:
  In this paper, we prove that relation-extensions of quasi-tilted algebras are
2-Calabi-Yau tilted. With the objective of describing the module category of a
cluster-tilted algebra of euclidean type, we define the notion of reflection so
that any two local slices can be reached one from the other by a sequence of
reflections and coreflections. We then give an algorithmic procedure for
constructing the tubes of a cluster-tilted algebra of euclidean type. Our main
result characterizes quasi-tilted algebras whose relation-extensions are
cluster-tilted of euclidean type.


title: The photon scattering cross-sections of atomic hydrogen

abstract:
  We present a unified view of the frequency dependence of the various
scattering processes involved when a neutral hydrogen atom interacts with a
monochromatic, linearly-polarized photon. A computational approach is employed
of the atom trapped by a finite-sized-box due to a finite basis-set expansion,
which generates a set of transition matrix elements between $E<0$ eigenstates
and $E>0$ pseudostates. We introduce a general computational methodology that
enables the computation of the frequency-dependent dipole transition
polarizability with one real and two different imaginary contributions. These
dipole transition polarizabilities are related to the cross-sections of
one-photon photoionization, Rayleigh, Raman, and Compton scattering. Our
numerical calculations reveal individual Raman scattering cross-sections above
threshold that can rapidly vanish and revive. Furthermore, our numerical
Compton cross-sections do not overtly suffer from the infra-red divergence
problem, and are three orders-of-magnitude higher than previous analytic-based
Compton scattering cross-sections. Our total photon-hydrogen scattering
cross-sections thus resolve the discrepancies between these previous
calculations and those in the N.I.S.T. `FFAST' database.


title:
New effects in the interaction between electromagnetic sources mediated
  by nonminimal Lorentz violating interactions

abstract:
  This paper is dedicated to the study of interactions between external sources
for the electromagnetic field in a Lorentz symmetry breaking scenario. We focus
on a particular higher derivative, Lorentz violating interaction that arises
from a specific model that was argued to lead to interesting effects in the low
energy phenomenology of light pseudoscalars interacting with photons. The kind
of higher derivative Lorentz violating interaction we discuss do not appear in
the well known Standard Model Extension, therefore they are called nonminimal.
They are usually expected to be relevant only at very high energies, but we
argue they might also induce relevant effects in low energy phenomena. Special
attention is given for phenomena that have no counterpart in Maxwell theory.


title:
An Exact Linearization Method for OLTC of Transformer in Branch Flow
  Model

abstract:
  The branch flow based optimal power flow(OPF) problem in radianlly operated
distribution networks can be exactly relazed to a second order cone programming
(SOCP) model without considering transformers. However, the introdution of
nonlinear transformer models will make the OPF model non-convex. This paper
presents an exact linearized transformer's OLTC model to keep the OPF model
convex via binary expanstion scheme and big-M method. Validity of the proposed
method is verified using IEEE 33-bus test system.


title:
Approximating the Spectral Sums of Large-scale Matrices using Chebyshev
  Approximations

abstract:
  Computation of the trace of a matrix function plays an important role in many
scientific computing applications, including applications in machine learning,
computational physics (e.g., lattice quantum chromodynamics), network analysis
and computational biology (e.g., protein folding), just to name a few
application areas. We propose a linear-time randomized algorithm for
approximating the trace of matrix functions of large symmetric matrices. Our
algorithm is based on coupling function approximation using Chebyshev
interpolation with stochastic trace estimators (Hutchinson's method), and as
such requires only implicit access to the matrix, in the form of a function
that maps a vector to the product of the matrix and the vector. We provide
rigorous approximation error in terms of the extremal eigenvalue of the input
matrix, and the Bernstein ellipse that corresponds to the function at hand.
Based on our general scheme, we provide algorithms with provable guarantees for
important matrix computations, including log-determinant, trace of matrix
inverse, Estrada index, Schatten p-norm, and testing positive definiteness. We
experimentally evaluate our algorithm and demonstrate its effectiveness on
matrices with tens of millions dimensions.


title: A geometric analogue of a conjecture of Gross and Reeder

abstract:
  Let G be a simple complex algebraic group. We prove that the irregularity of
the adjoint connection of an irregular flat G-bundle on the formal punctured
disk is always greater than or equal to the rank of G. This can be considered
as a geometric analogue of a conjecture of Gross and Reeder. We will also show
that the irregular connections with minimum adjoint irregularity are precisely
the (formal) Frenkel-Gross connections.


title: Microcanonical Szil\'ard engines beyond the quasistatic regime

abstract:
  We discuss the possibility of extracting energy from a single thermal bath
using microcanonical Szil\'ard engines operating in finite time. This extends
previous works on the topic which are restricted to the quasistatic regime. The
feedback protocol is implemented based on linear response predictions of the
excess work. It is claimed that the underlying mechanism leading to energy
extraction does not violate Liouville's theorem and preserves ergodicity
throughout the cycle. We illustrate our results with several examples including
an exactly solvable model.


title: GW Librae: Still Hot Eight Years Post-Outburst

abstract:
  We report continued Hubble Space Telescope (HST) ultraviolet spectra and
ground-based optical photometry and spectroscopy of GW Librae eight years after
its largest known dwarf nova outburst in 2007. This represents the longest
cooling timescale measured for any dwarf nova. The spectra reveal that the
white dwarf still remains about 3000 K hotter than its quiescent value. Both
ultraviolet and optical light curves show a short period of 364-373 s, similar
to one of the non-radial pulsation periods present for years prior to the
outburst, and with a similar large UV/optical amplitude ratio. A large
modulation at a period of 2 h (also similar to that observed prior to outburst)
is present in the optical data preceding and during the HST observations, but
the satellite observation intervals did not cover the peaks of the optical
modulation so it is not possible to determine its corresponding UV amplitude.
The similarity of the short and long periods to quiescent values implies the
pulsating, fast spinning white dwarf in GW Lib may finally be nearing its
quiescent configuration.


title:
Effect of temperature gradient on heavy quark anti-quark potential using
  gravity dual model

abstract:
  Thermal systems have traditionally been modeled via Euclideanized space by
analytical continuation of time to an imaginary time. We extend the concept to
static thermal gradients by recasting the temperature variation as a variation
in the Euclidean metric. We apply this prescription to determine the Quark
anti-Quark potential in a system with thermal gradient. A naturally occurring
QCD medium with thermal gradients is a Quark Gluon Plasma (QGP). However, the
QGP evolves in time. Hence, we use a quasi-stationary approximation, which is
applicable only if the rate of time evolution is slow. The application of our
proposal to a Quark anti-Quark potential in QGP can be seen as a step towards a
more exact theory which would incorporate time varying thermal gradients. The
effect of a static temperature gradient on the Quark anti-Quark potential is
analyzed using a gravity dual model. A non-uniform black string metric is
developed, by perturbing the Schwarzchild metric, which allows to incorporate
the temperature gradient in the dual AdS space. Finally, an expression for the
Quark anti-Quark potential, in the presence of a static temperature gradient,
is derived.


title: Physics at a 100 TeV pp collider: beyond the Standard Model phenomena

abstract:
  This report summarises the physics opportunities in the search and study of
physics beyond the Standard Model at a 100 TeV pp collider.


title:
Quadrangular embeddings of complete graphs and the Even Map Color
  Theorem (with details)

abstract:
  Hartsfield and Ringel constructed orientable quadrangular embeddings of the
complete graph $K_n$ for $n\equiv 5 \pmod 8$, and nonorientable ones for $n \ge
9$ and $n\equiv 1 \pmod 4$. These provide minimal quadrangulations of their
underlying surfaces. We extend these results to determine, for every complete
graph $K_n$, $n \ge 4$, the minimum genus, both orientable and nonorientable,
for the surface in which $K_n$ has an embedding with all faces of degree at
least $4$, and also for the surface in which $K_n$ has an embedding with all
faces of even degree. These last embeddings provide sharpness examples for a
result of Hutchinson bounding the chromatic number of graphs embedded with all
faces of even degree, completing the proof of the Even Map Color Theorem. We
also show that if a connected simple graph $G$ has a perfect matching and a
cycle then the lexicographic product $G[K_4]$ has orientable and nonorientable
quadrangular embeddings; this provides new examples of minimal
quadrangulations.


title: Physical properties of CO-dark molecular gas traced by C$^+$

abstract:
  Neither HI nor CO emission can reveal a significant quantity of so-called
dark gas in the interstellar medium (ISM). It is considered that CO-dark
molecular gas (DMG), the molecular gas with no or weak CO emission, dominates
dark gas. We identified 36 DMG clouds with C$^+$ emission (data from Galactic
Observations of Terahertz C+ (GOT C+) project) and HINSA features. Based on
uncertainty analysis, optical depth of HI $\tau\rm_{HI}$ of 1 is a reasonable
value for most clouds. With the assumption of $\tau\rm_{HI}=1$, these clouds
were characterized by excitation temperatures in a range of 20 K to 92 K with a
median value of 55 K and volume densities in the range of $6.2\times10^1$
cm$^{-3}$ to $1.2\times 10^3$ cm$^{-3}$ with a median value of $2.3\times 10^2$
cm$^{-3}$. The fraction of DMG column density in the cloud ($f\rm_{DMG}$)
decreases with increasing excitation temperature following an empirical
relation $f\rm_{DMG}=-2.1\times 10^{-3}T_(ex,\tau_{HI}=1)$+1.0. The relation
between $f\rm_{DMG}$ and total hydrogen column density $N_H$ is given by
$f\rm_{DMG}$=$1.0-3.7\times 10^{20}/N_H$. The values of $f\rm_{DMG}$ in the
clouds of low extinction group ($A\rm_V \le 2.7$ mag) are consistent with the
results of the time-dependent, chemical evolutionary model at the age of ~ 10
Myr. Our empirical relation cannot be explained by the chemical evolutionary
model for clouds in the high extinction group ($A\rm_V > 2.7$ mag). Compared to
clouds in the low extinction group ($A\rm_V \le 2.7$ mag), clouds in the high
extinction group ($A\rm_V > 2.7$ mag) have comparable volume densities but
excitation temperatures that are 1.5 times lower. Moreover, CO abundances in
clouds of the high extinction group ($A\rm_V > 2.7$ mag) are $6.6\times 10^2$
times smaller than the canonical value in the Milky Way. #[Full version of
abstract is shown in the text.]#


title: Graph Clustering with Density-Cut

abstract:
  How can we find a good graph clustering of a real-world network, that allows
insight into its underlying structure and also potential functions? In this
paper, we introduce a new graph clustering algorithm Dcut from a density point
of view. The basic idea is to envision the graph clustering as a density-cut
problem, such that the vertices in the same cluster are densely connected and
the vertices between clusters are sparsely connected. To identify meaningful
clusters (communities) in a graph, a density-connected tree is first
constructed in a local fashion. Owing to the density-connected tree, Dcut
allows partitioning a graph into multiple densely tight-knit clusters directly.
We demonstrate that our method has several attractive benefits: (a) Dcut
provides an intuitive criterion to evaluate the goodness of a graph clustering
in a more natural and precise way; (b) Built upon the density-connected tree,
Dcut allows identifying the meaningful graph clusters of densely connected
vertices efficiently; (c) The density-connected tree provides a connectivity
map of vertices in a graph from a local density perspective. We systematically
evaluate our new clustering approach on synthetic as well as real data to
demonstrate its good performance.


title:
Yukawa sector for LFV in $h\to \mu\tau$ and CP violation in $h\to
  \tau\tau$

abstract:
  The Higgs boson discovered at the LHC opened a new chapter for particle
physics. Its properties need to be studied in detail to distinguish a purely
standard model (SM) Higgs boson from one of many scalars in an enlarged Higgs
sector. The CMS collaboration has reported a possible lepton flavor violating
(LFV) signal $h\to\mu\tau$, which if confirmed, implies that the Higgs sector
is larger than in the SM. New physics responsible for this type of decay may,
in general, also introduce other observable effects such as charge-parity (CP)
violation in $h\to \tau\tau$. We study two types of models that single out the
third generation and can induce large $h \to \mu\tau$ rates with different
consequences for CP violation in $h \to \tau \tau$. Predictions for the size of
the CP violating couplings require knowledge of the lepton Yukawa matrices and
we discuss this in the context of two different textures considering all
existing constraints.


title:
Delay Optimal Scheduling of Arbitrarily Bursty Traffic over Multi-State
  Time-Varying Channels

abstract:
  In this paper, we study joint queue-aware and channel-aware scheduling of
arbitrarily bursty traffic over multi-state time-varying channels, where the
bursty packet arrival in the network layer, the backlogged queue in the data
link layer, and the power adaptive transmission with fixed modulation in the
physical layer are jointly considered from a cross-layer perspective. To
achieve minimum queueing delay given a power constraint, a probabilistic
cross-layer scheduling policy is proposed, and characterized by a Markov chain
model. To describe the delay-power tradeoff, we formulate a non-linear
optimization problem, which however is very challenging to solve. To handle
with this issue, we convert the optimization problem into an equivalent Linear
Programming (LP) problem, which allows us to obtain the optimal threshold-based
scheduling policy with an optimal threshold imposed on the queue length in
accordance with each channel state.


title: Rapid and reliable sky localization of gravitational wave sources

abstract:
  The first detection of gravitational waves by LIGO from the merger of two
compact objects has sparked new interest in detecting electromagnetic
counterparts to these violent events. For mergers involving neutron stars, it
is thought that prompt high-energy emission in gamma rays and x-rays will be
followed days to weeks later by an afterglow in visible light, infrared and
radio. Rapid sky localization using the data from a network of gravitational
wave detectors is essential to maximize the chances of making a joint
detection. Here I describe a new technique that is able to produce accurate,
fully Bayesian sky maps in seconds or less. The technique can be applied to
spin-precessing compact binaries, and can take into account detector
calibration and spectral estimation uncertainties.


title:
Spatial-mode-interaction-induced dispersive-waves and their active
  tuning in microresonators

abstract:
  The nonlinear propagation of optical pulses in dielectric waveguides and
resonators provides a laboratory to investigate a wide range of remarkable
interactions. Many of the resulting phenomena find applications in optical
systems. One example is dispersive wave generation, the optical analog of
Cherenkov radiation. These waves have an essential role in fiber spectral
broadeners that are routinely used in spectrocopy and metrology. Dispersive
waves form when a soliton pulse begins to radiate power as a result of
higher-order dispersion. Recently, dispersive wave generation in microcavities
has been reported by phase matching the waves to dissipative Kerr cavity (DKC)
solitons. Here, it is shown that spatial mode interactions within a microcavity
can also be used to induce dispersive waves. These interactions are normally
avoided altogether in DKC soliton generation. The soliton self frequency shift
is also shown to induce fine tuning control of the dispersive wave frequency.
Both this mechanism and spatial mode interactions provide a new method to
spectrally control these important waves.


title:
Message Passing for Analysis and Resilient Design of Self-Healing
  Interdependent Cyber-Physical Networks

abstract:
  Coupling cyber and physical systems gives rise to numerous engineering
challenges and opportunities. An important challenge is the contagion of
failure from one system to another, that can lead to large scale cascading
failures. On the other hand, self-healing ability emerges as a valuable
opportunity where the overlay cyber network can cure failures in the underlying
physical network. To capture both self-healing and contagion, we introduce a
factor graph representation of inter-dependent cyber-physical systems in which
factor nodes represent various node functionalities and the edges capture the
interactions between the nodes. We develop a message passing algorithm to study
the dynamics of failure propagation and healing in this representation. Through
applying a fixed-point analysis to this algorithm, we investigate the network
reaction to initial disruptions. Our analysis provides simple yet critical
guidelines for choosing network parameters to achieve resiliency against
cascading failures.


title: Unified quantum density matrix description of coherence and polarization

abstract:
  The properties of coherence and polarization of light has been the subject of
intense investigations and form the basis of many technological applications.
These concepts which historically have been treated independently can now be
formulated under a single classical theory. Here, we derive a quantum
counterpart for this theory, with basis on a density matrix formulation, which
describes jointly the coherence and polarization properties of an ensemble of
photons. The method is used to show how the degree of polarization of a
specific class of mixed states changes on propagation in free space, and how an
interacting environment can suppress the coherence and polarization degrees of
a general state. This last application can be particularly useful in the
analysis of decoherence effects in optical quantum information implementations.


title: Optimality Conditions for Inventory Control

abstract:
  This tutorial describes recently developed general optimality conditions for
Markov Decision Processes that have significant applications to inventory
control. In particular, these conditions imply the validity of optimality
equations and inequalities. They also imply the convergence of value iteration
algorithms. For total discounted-cost problems only two mild conditions on the
continuity of transition probabilities and lower semi-continuity of one-step
costs are needed. For average-cost problems, a single additional assumption on
the finiteness of relative values is required. The general results are applied
to periodic-review inventory control problems with discounted and average-cost
criteria without any assumptions on demand distributions. The case of partially
observable states is also discussed.


title:
The formula for the permutation of mutation sequences in $A_n$ straight
  orientation

abstract:
  In this paper we state and prove a formula for the permutations associated to
reddening and loop sequences in $A_n$ straight orientation using the picture
group. In particular this applies to maximal green sequences in $A_n$ straight
orientation. Furthermore we extend the definition and formula of the associated
permutation to arbitrary mutation sequences based on our results. We introduce
the concept of standard matrices which gives a canonical order on
indecomposable components of cluster-tilting objects. Preservation of
standardness of C-matrices by a combination of a mutation and its associated
permutation gives the formula.


title:
Strichartz estimate and nonlinear Klein-Gordon on non-trapping
  scattering space

abstract:
  We study the nonlinear Klein-Gordon equation on a product space $M=\R\times
X$ with metric $\tilde{g}=dt^2-g$ where $g$ is the scattering metic on $X$. We
establish the global-in-time Strichartz estimate for Klein-Gordon equation
without loss of derivative by using the microlocalized spectral measure of
Laplacian on scattering manifold showed in \cite{HZ} and a Littlewood-Paley
squarefunction estimate proved in \cite{Zhang}. We prove the global existence
and scattering for a family of nonlinear Klein-Gordon equations for small
initial data with minimum regularity on this setting.


title: Projecting 3D color codes onto 3D toric codes

abstract:
  Toric codes and color codes are two important classes of topological codes.
Kubica, Yoshida, and Pastawski showed that any $D$-dimensional color code can
be mapped to a finite number of toric codes in $D$-dimensions. In this paper we
propose an alternate map of 3D color codes to 3D toric codes with a view to
decoding 3D color codes. Our approach builds on Delfosse's result for 2D color
codes and exploits the topological properties of these codes. Our result
reduces the decoding of 3D color codes to that of 3D toric codes. Bit flip
errors are decoded by projecting on one set of 3D toric codes while phase flip
errors are decoded by projecting onto another set of 3D toric codes.


title:
An Approach to Cluster Structures on Moduli of Local Systems for General
  Groups

abstract:
  Let $S$ be a surface, $G$ a simply-connected classical group, and $G'$ the
associated adjoint form of the group. In \cite{FG1}, it was shown that the
moduli spaces of framed local systems $\X_{G',S}$ and $\A_{G,S}$ have the
structure of cluster varieties, and thus together form a cluster ensemble, when
$G$ had type $A$. This was extended to classical groups in \cite{Le}. In this
paper we give an algorithm for constructing the cluster structure for general
reductive groups $G$. The algorithm can be carried out under some mild
hypotheses, which we explain, and which we believe hold in general. We show
that these hypotheses hold when $G$ has type $G_2$, and therefore we are able
to construct the cluster structure in this case. We also illustrate our
approach by rederiving the cluster structure for $G$ of type $A$. Our goals are
to give some heuristics for the approach taken in \cite{Le}, point out the
difficulties that arise for more general groups, and to record some useful
calculations. Forthcoming work by Goncharov and Shen gives a different approach
to constructing the cluster structure on $\X_{G',S}$ and $\A_{G,S}$. We hope
that some of the ideas here complement their more comprehensive work.


title:
Gaussian benchmark for optical communication aiming towards ultimate
  capacity

abstract:
  We establish the fundamental limit of communication capacity within Gaussian
schemes under phase-insensitive Gaussian channels, which employ multimode
Gaussian states for encoding and collective Gaussian operations and
measurements for decoding. We prove that this Gaussian capacity is additive,
i.e., its upper bound occurs with separable encoding and separable receivers so
that a single-mode communication suffices to achieve the largest capacity under
Gaussian schemes. This rigorously characterizes the gap between the ultimate
Holevo capacity and the capacity within Gaussian communication, showing that
Gaussian regime is not sufficient to achieve the Holevo bound particularly in
the low-photon regime. Furthermore the Gaussian benchmark established here can
be used to critically assess the performance of non-Gaussian protocols for
optical communication. We move on to identify non-Gaussian schemes to beat the
Gaussian capacity and show that a non-Gaussian receiver recently implemented by
Becerra et al. [Nat. Photon. 7, 147 (2013)] can achieve this aim with an
appropriately chosen encoding strategy.


title:
Optimal quantizers for probability distributions on nonhomogeneous
  R-triangles

abstract:
  Quantization of a probability distribution refers to the idea of estimating a
given probability by a discrete probability supported by a finite set. In this
paper, we have considered a Borel probability measure $P$ on $\mathbb R^2$
which has support the R-triangle generated by a set of three contractive
similarity mappings on $\mathbb R^2$. For this probability measure, the optimal
sets of $n$-means and the $n$th quantization error are determined for all
$n\geq 2$.


title: Explosive magnetorotational instability in Keplerian disks

abstract:
  Differentially rotating disks under the effect of axial magnetic field are
prone to a nonlinear explosive magnetorotational instability (EMRI).
  The dynamic equations that govern the temporal evolution of the amplitudes of
three weakly-detuned resonantly interacting modes are derived. As distinct from
exponential growth in the strict resonance triads EMRI occurs due to the
resonant interactions of a MRI mode with stable Alfv\'en-Coriolis and
magnetosonic modes. Numerical solutions of the dynamic equations for amplitudes
of a triad indicate that two types of perturbations behavior can be excited for
resonance conditions: (i) EMRI which leads to infinite values of the three
amplitudes within a finite time, and (ii) bounded irregular oscillations of all
three amplitudes.
  Asymptotic explicit solutions of the dynamic equations are obtained for EMRI
regimes and are shown to match the numerical solutions near the explosion time.


title:
Control of the Extension-Flexion Cycle of Human Knees During Bicycle
  Riding by a Synergy of Solitary Muscular Excitations and Contractions

abstract:
  A Hill-type model is proposed for the extension-flexion cycle of human knees
during bicycle riding. The extension-flexion cycle is controlled by a synergy
of muscular excitations and contractions of the knee musculature. Muscular
action potentials are modeled by Sine-Gordon kinks, while titin-influenced
actomyosin contractionsare modeled by Korteweg-de Vries solitons. As an
application, the total knee arthroplasty is discussed.


title: Screening operators for W-algebras

abstract:
  Let $\mathfrak{g}$ be a simple finite-dimensional Lie superalgebra with a
non-degenerate supersymmetric even invariant bilinear form, $f$ a nilpotent
element in the even part of $\mathfrak{g}$, $\Gamma$ a good grading of
$\mathfrak{g}$ for $f$ and $\mathcal{W}^{k}(\mathfrak{g},f;\Gamma)$ the
$\mathcal{W}$-algebra associated with $\mathfrak{g},f,k,\Gamma$ defined by the
generalized Drinfeld-Sokolov reduction. In this paper, we present each
$\mathcal{W}$-algebra as the intersection of kernels of the screening
operators, acting on the tensor vertex superalgebra of an affine vertex
superalgebra and a neutral free superfermion vertex superalgebra. As
applications, we prove that the $\mathcal{W}$-algebra associated with a regular
nilpotent element in $\mathfrak{osp}(1,2n)$ is isomorphic to the
$\mathcal{W}B_{n}$-algebra introduced by Fateev and Lukyanov, and that the
$\mathcal{W}$-algebra associated with a subregular nilpotent element in
$\mathfrak{sl}_{n}$ is isomorphic to the $\mathcal{W}^{(2)}_{n}$-algebra
introduced by Feigin and Semikhatov.


title:
Stellar Populations of BCGs, Close Companions and Intracluster Light in
  Abell 85, Abell 2457 and IIZw108

abstract:
  We present the first results from an integral field (IFU) spectroscopic
survey of a 75kpc region around three Brightest Cluster Galaxies (BCGs),
combining over 100 IFU fibres to study the intracluster light (ICL). We fit
population synthesis models to estimate age and metallicity. For Abell 85 and
Abell 2457, the ICL is best-fit with a fraction of old, metal-rich stars like
in the BCG, but requires 30-50% young and metal-poor stars, a component not
found in the BCGs. This is consistent with the ICL having been formed by a
combination of interactions with less massive, younger, more metal-poor cluster
members in addition to stars that form the BCG. We find that the three galaxies
are in different stages of evolution and may be the result of different
formation mechanisms. The BCG in Abell 85 is near a relatively young,
metal-poor galaxy, but the dynamical friction timescale is long and the two are
unlikely to be undergoing a merger. The outer regions of Abell 2457 show a
higher relative fraction of metal-poor stars, and we find one companion, with a
higher fraction of young, metal-poor stars than the BCG, which is likely to
merge within a gigayear. Several luminous red galaxies are found at the centre
of the cluster IIZw108, with short merger timescales, suggesting the system is
about to embark on a series of major mergers to build up a dominant BCG. The
young, metal-poor component found in the ICL is not found in the merging
galaxies.


title: Smooth Imitation Learning for Online Sequence Prediction

abstract:
  We study the problem of smooth imitation learning for online sequence
prediction, where the goal is to train a policy that can smoothly imitate
demonstrated behavior in a dynamic and continuous environment in response to
online, sequential context input. Since the mapping from context to behavior is
often complex, we take a learning reduction approach to reduce smooth imitation
learning to a regression problem using complex function classes that are
regularized to ensure smoothness. We present a learning meta-algorithm that
achieves fast and stable convergence to a good policy. Our approach enjoys
several attractive properties, including being fully deterministic, employing
an adaptive learning rate that can provably yield larger policy improvements
compared to previous approaches, and the ability to ensure stable convergence.
Our empirical results demonstrate significant performance gains over previous
approaches.


title: Multicore fibre technology - the road to multimode photonics

abstract:
  For the past forty years, optical fibres have found widespread use in
ground-based and space-based instruments. In most applications, these fibres
are used in conjunction with conventional optics to transport light. But
photonics offers a huge range of optical manipulations beyond light transport
that were rarely exploited before 2001. The fundamental obstacle to the broader
use of photonics is the difficulty of achieving photonic action in a multimode
fibre. The first step towards a general solution was the invention of the
photonic lantern (Leon-Saval, Birks & Bland-Hawthorn 2005) and the delivery of
high-efficiency devices (< 1 dB loss) five years on (Noordegraaf et al 2009).
Multicore fibres (MCF), used in conjunction with lanterns, are now enabling an
even bigger leap towards multimode photonics. Until recently, the single-moded
cores in MCFs were not sufficiently uniform to achieve telecom (SMF-28)
performance. Now that high-quality MCFs have been realized, we turn our
attention to printing complex functions (e.g. Bragg gratings for OH
suppression) into their N cores. Our first work in this direction used a
Mach-Zehnder interferometer (near-field phase mask) but this approach was only
adequate for N=7 MCFs as measured by the grating uniformity (Lindley et al
2014). We have now built a Sagnac interferometer that gives a three-fold
increase in the depth of field sufficient to print across N > 127 cores. We
achieved first light this year with our 500mW Sabre FRED laser. These are
sophisticated and complex interferometers. We report on our progress to date
and summarize our first-year goals which include multimode OH suppression
fibres for the Anglo-Australian Telescope/PRAXIS instrument and the Discovery
Channel Telescope/MOHSIS instrument under development at the University of
Maryland.


title:
Measurement of the $p(e,e'\pi^+)n$ reaction close to threshold and at
  low $Q^2$

abstract:
  The cross section of the $p(e,e'\pi^+)n$ reaction has been measured for five
kinematic settings at an invariant mass of $W = 1094$ MeV and for a
four-momentum transfer of $Q^2 = 0.078$ (GeV/$c$)$^2$. The measurement has been
performed at MAMI using a new short-orbit spectrometer (SOS) of the A1
collaboration, intended for detection of low-energy pions. The transverse and
longitudinal cross section terms were separated using the Rosenbluth method and
the transverse-longitudinal interference term has been determined from the
left-right asymmetry. The experimental cross section terms are compared with
the calculations of three models: DMT2001, MAID2007 and $\chi$MAID. The results
show that we do not yet understand the dynamics of the fundamental pion.


title:
The singular integral operator and its commutator on weighted Morrey
  spaces

abstract:
  In this paper, we give necessary conditions and sufficient conditions
respectively for the boundedness of the singular integral operator on the
weighted Morrey spaces. We observe the phenomenon unique to the case of Morrey
spaces; the $A_q$-theory by Muckenhoupt and Wheeden does not suffice. We also
discuss the boundedness of the commutators. The difference between the maximal
operator and the singular integral operators will be clarified. Further, the
property of the sharp maximal operator is investigated.


title: Synthesizing Dynamic Patterns by Spatial-Temporal Generative ConvNet

abstract:
  Video sequences contain rich dynamic patterns, such as dynamic texture
patterns that exhibit stationarity in the temporal domain, and action patterns
that are non-stationary in either spatial or temporal domain. We show that a
spatial-temporal generative ConvNet can be used to model and synthesize dynamic
patterns. The model defines a probability distribution on the video sequence,
and the log probability is defined by a spatial-temporal ConvNet that consists
of multiple layers of spatial-temporal filters to capture spatial-temporal
patterns of different scales. The model can be learned from the training video
sequences by an "analysis by synthesis" learning algorithm that iterates the
following two steps. Step 1 synthesizes video sequences from the currently
learned model. Step 2 then updates the model parameters based on the difference
between the synthesized video sequences and the observed training sequences. We
show that the learning algorithm can synthesize realistic dynamic patterns.


title:
Sodium abundances of AGB and RGB stars in galactic globular clusters I.
  Analysis and results of NGC 2808

abstract:
  Galactic globular clusters (GC) are known to have multiple stellar
populations and be characterised by similar chemical features, e.g. O-Na
anti-correlation. While second-population stars, identified by their Na
overabundance, have been found from the main sequence turn-off up to the tip of
the red giant branch in various Galactic GCs, asymptotic giant branch (AGB)
stars have rarely been targeted. The recent finding that NGC 6752 lacks an
Na-rich AGB star has thus triggered new studies on AGB stars in GCs, since this
result questions our basic understanding of GC formation and stellar evolution
theory. In order to compare the Na abundance distributions of AGB and RGB stars
in Galactic GCs and investigate whether the presence of Na-rich stars on the
AGB is metallicity-dependent, we obtained the high-resolution spectra with the
multi-object high-resolution spectrograph FLAMES on ESO/VLT for a sample of AGB
and RGB stars in the Galactic GC NGC 2808. The accurate Na abundances were
derived for 31 AGB and 40 RGB stars. We find that NGC 2808 has a mean
metallicity of -1.11 $\pm$ 0.08 dex, in good agreement with earlier analyses.
Comparable Na abundance dispersions are derived for our AGB and RGB samples,
with the AGB stars being slightly more concentrated than the RGB stars. The
ratios of Na-poor first-population to Na-rich second-population stars are 45:55
in the AGB sample and 48:52 in the RGB sample. NGC 2808 has Na-rich
second-population AGB stars, which turn out to be even more numerous - in
relative terms - than their Na-poor AGB counterparts and the Na-rich stars on
the RGB. Our findings are well reproduced by the fast rotating massive stars
scenario and they do not contradict the recent results that there is not an
Na-rich AGB star in NGC 6752. NGC 2808 thus joins the larger group of Galactic
GCs for which Na-rich second-population stars on the AGB have recently been
found.


title:
A Graph Theoretical Analysis of Low-Power Coding Schemes for One-Hop
  Networks

abstract:
  Coding schemes with extremely low computational complexity are required for
particular applications, such as wireless body area networks, in which case
both very high data accuracy and very low power-consumption are required
features. In this paper, coding schemes arising from incidence matrices of
graphs are proposed. An analysis of the resilience of such codes to erasures is
given using graph theoretical arguments; decodability of a graph is
characterized in terms of the rank of its incidence matrix. Bounds are given on
the number of decodable subgraphs of a graph and the number of edges that must
be deleted in order to arrive at an undecodable subgraph. Algorithms to
construct codes that are optimal with respect to these bounds are presented.


title:
Efficient, designable, and broad-bandwidth optical extinction via
  aspect-ratio-tailored silver nanodisks

abstract:
  Subwavelength resonators, ranging from single atoms to metallic
nanoparticles, typically exhibit a narrow-bandwidth response to optical
excitations. We computationally design and experimentally synthesize tailored
distributions of silver nanodisks to extinguish light over broad and varied
frequency windows. We show that metallic nanodisks are two-to-ten-times more
efficient in absorbing and scattering light than common structures, and can
approach fundamental limits to broadband scattering for subwavelength
particles. We measure broadband extinction per volume that closely approaches
theoretical predictions over three representative visible-range wavelength
windows, confirming the high efficiency of nanodisks and demonstrating the
collective power of computational design and experimental precision for
developing new photonics technologies.


title: Marginal Estimation of Parameter Driven Binomial Time Series Models

abstract:
  This paper develops asymptotic theory for estimation of parameters in
regression models for binomial response time series where serial dependence is
present through a latent process. Use of generalized linear model (GLM)
estimating equations leads to asymptotically biased estimates of regression
coefficients for binomial responses. An alternative is to use marginal
likelihood, in which the variance of the latent process but not the serial
dependence is accounted for. In practice this is equivalent to using
generalized linear mixed model estimation procedures treating the observations
as independent with a random effect on the intercept term in the regression
model. We prove this method leads to consistent and asymptotically normal
estimates even if there is an autocorrelated latent process. Simulations
suggest that the use of marginal likelihood can lead to GLM estimates result.
This problem reduces rapidly with increasing number of binomial trials at each
time point but, for binary data, the chance of it can remain over 45% even in
very long time series. We provide a combination of theoretical and heuristic
explanations for this phenomenon in terms of the properties of the regression
component of the model and these can be used to guide application of the method
in practice.


title: Proper Motion of the Draco Dwarf Galaxy from Subaru Suprime-Cam Data

abstract:
  We have measured the absolute proper motion of the Draco dwarf spheroidal
galaxy using Subaru Suprime-Cam images taken at three epochs, with time
baselines of 4.4 and 7 years. The magnitude limit of the proper-motion study is
i=25, thus allowing for thousands of background galaxies and Draco stars to be
used to perform extensive astrometric tests and to derive the correction to an
inertial reference frame. The derived proper motion is (mu_alpha, mu_delta)
=(-0.284 +- 0.047, -0.289 +-0.041) mas/yr. This motion implies an orbit that
takes Draco to a pericenter of $\sim 20$ kpc; a somewhat disruptive orbit
suggesting that tides might account for the rising velocity-dispersion profile
of Draco seen in line-of-sight velocity studies. The orbit is only marginally
consistent with Draco's membership to the vast polar structure of Galactic
satellites, in contrast to a recent HST proper-motion measurement that finds
alignment very likely. Our study is a test case to demonstrate that deep
imaging with mosaic cameras of appropriate resolution can be used for
high-accuracy, ground-based proper-motion measurement. As a useful by-product
of the study, we also identify two faint brown-dwarf candidates in the
foreground field.


title: On the structure of Bethe vectors

abstract:
  The structure of Bethe vectors for generalised models associated with the
XXX- and XXZ-type R-matrix is investigated. The Bethe vectors in terms of
two--component and multi--component models are described. Consequently, their
structure in terms of local variables and operators is provided. This, as a
consequence, proves the equivalence of coordinate and algebraic Bethe ansatzes
for the Heisenberg XXX and XXZ spin chains.


title:
Question Answering over Knowledge Base with Neural Attention Combining
  Global Knowledge Information

abstract:
  With the rapid growth of knowledge bases (KBs) on the web, how to take full
advantage of them becomes increasingly important. Knowledge base-based question
answering (KB-QA) is one of the most promising approaches to access the
substantial knowledge. Meantime, as the neural network-based (NN-based) methods
develop, NN-based KB-QA has already achieved impressive results. However,
previous work did not put emphasis on question representation, and the question
is converted into a fixed vector regardless of its candidate answers. This
simple representation strategy is unable to express the proper information of
the question. Hence, we present a neural attention-based model to represent the
questions dynamically according to the different focuses of various candidate
answer aspects. In addition, we leverage the global knowledge inside the
underlying KB, aiming at integrating the rich KB information into the
representation of the answers. And it also alleviates the out of vocabulary
(OOV) problem, which helps the attention model to represent the question more
precisely. The experimental results on WEBQUESTIONS demonstrate the
effectiveness of the proposed approach.


title: Fast Bayesian whole-brain fMRI analysis with spatial 3D priors

abstract:
  Spatial whole-brain Bayesian modeling of task-related functional magnetic
resonance imaging (fMRI) is a great computational challenge. Most of the
currently proposed methods therefore do inference in subregions of the brain
separately or do approximate inference without comparison to the true posterior
distribution. A popular such method, which is now the standard method for
Bayesian single subject analysis in the SPM software, is introduced in Penny et
al. (2005b). The method processes the data slice-by-slice and uses an
approximate variational Bayes (VB) estimation algorithm that enforces posterior
independence between activity coefficients in different voxels. We introduce a
fast and practical Markov chain Monte Carlo (MCMC) scheme for exact inference
in the same model, both slice-wise and for the whole brain using a 3D prior on
activity coefficients. The algorithm exploits sparsity and uses modern
techniques for efficient sampling from high-dimensional Gaussian distributions,
leading to speed-ups without which MCMC would not be a practical option. Using
MCMC, we are for the first time able to evaluate the approximate VB posterior
against the exact MCMC posterior, and show that VB can lead to spurious
activation. In addition, we develop an improved VB method that drops the
assumption of independent voxels a posteriori. This algorithm is shown to be
much faster than both MCMC and the original VB for large datasets, with
negligible error compared to the MCMC posterior.


title:
Exploiting AIS Data for Intelligent Maritime Navigation: A Comprehensive
  Survey

abstract:
  The Automatic Identification System (AIS) tracks vessel movement by means of
electronic exchange of navigation data between vessels, with onboard
transceiver, terrestrial and/or satellite base stations. The gathered data
contains a wealth of information useful for maritime safety, security and
efficiency. This paper surveys AIS data sources and relevant aspects of
navigation in which such data is or could be exploited for safety of seafaring,
namely traffic anomaly detection, route estimation, collision prediction and
path planning.


title: Pseudospin Vortex Ring with a Nodal Line in Three Dimensions

abstract:
  We present a model of a topological semimetal in three dimensions (3D) whose
energy spectrum exhibits a nodal line acting as a vortex ring; this in turn is
linked by a pseudospin structure akin to that of a smoke ring. Contrary to a
Weyl point node spectrum, the vortex ring gives rise to skyrmionic pseudospin
patterns in cuts on both sides of the nodal ring plane; this pattern covers the
full Brillouin zone, thus leading to a new, `maximal', anomalous Hall effect in
a 3D semimetal. Tuning a model parameter shrinks the vortex ring until it
vanishes, giving way to a pair of Weyl nodes of opposite chirality. This
establishes a connection between two distinct momentum-space topologies - that
of a vortex ring (a circle of singularity) and a monopole-anti-monopole pair
(two point singularities). We present the model both as a low-energy continuum
and a two-band tight-binding lattice model. Its simplicity permits an
analytical computation of its Landau level spectrum.


title:
Testing for Serial Dependence in Binomial Time Series I: Parameter
  Driven Models

abstract:
  Binomial time series in which the logit of the probability of success is
modelled as a linear function of observed regressors and a stationary latent
Gaussian process are considered. Score tests are developed to first test for
the existence of a latent process and, subsequent to that, evidence of serial
dependence in that latent process. The test for the existence of a latent
process is important because, if one is present, standard logistic regression
methods will produce inconsistent estimates of the regression parameters.
However the score test is non-standard and any serial dependence in the latent
process will require consideration of nuisance parameters which cannot be
estimated under the null hypothesis of no latent process. The paper describes
how a supremum-type test can be applied. If a latent process is detected,
consistent estimation of its variance and the regression parameters can be done
using marginal estimation which is easily implemented using generalised linear
mixed model methods. The test for serial dependence in a latent process does
not involve nuisance parameters and is based on the covariances between
residuals centered at functions of the latent process conditional on the
observations. This requires numerical integration in order to compute the test
statistic. Relevant asymptotic results are derived and confirmed using
simulation evidence. Application to binary and binomial time series is made.
For binary series in particular, a complication is that the variance of the
latent process, even if present, can be estimated to be zero with a high
probability.


title:
Detecting Serial Dependence in Binomial Time Series II: Observation
  Driven Models

abstract:
  The detection of serial dependence in binary or binomial valued time series
is difficult using standard time series methods, particularly when there are
regression effects to be modelled. In this paper we derive score-type tests for
detecting departures from independence in the directions of the GLARMA\ and
BARMA\ type observation driven models. These score tests can easily be applied
using a standard logistic regression and so may have appeal to practitioners
who wish to initially assess the need to incorporate serial dependence effects.
To deal with the nuisance parameters in some GLARMA models a supremum type test
is implemented.


title:
A Graph-Based Semi-Supervised k Nearest-Neighbor Method for Nonlinear
  Manifold Distributed Data Classification

abstract:
  $k$ Nearest Neighbors ($k$NN) is one of the most widely used supervised
learning algorithms to classify Gaussian distributed data, but it does not
achieve good results when it is applied to nonlinear manifold distributed data,
especially when a very limited amount of labeled samples are available. In this
paper, we propose a new graph-based $k$NN algorithm which can effectively
handle both Gaussian distributed data and nonlinear manifold distributed data.
To achieve this goal, we first propose a constrained Tired Random Walk (TRW) by
constructing an $R$-level nearest-neighbor strengthened tree over the graph,
and then compute a TRW matrix for similarity measurement purposes. After this,
the nearest neighbors are identified according to the TRW matrix and the class
label of a query point is determined by the sum of all the TRW weights of its
nearest neighbors. To deal with online situations, we also propose a new
algorithm to handle sequential samples based a local neighborhood
reconstruction. Comparison experiments are conducted on both synthetic data
sets and real-world data sets to demonstrate the validity of the proposed new
$k$NN algorithm and its improvements to other version of $k$NN algorithms.
Given the widespread appearance of manifold structures in real-world problems
and the popularity of the traditional $k$NN algorithm, the proposed manifold
version $k$NN shows promising potential for classifying manifold-distributed
data.


title:
Cooperon condensation and intra-valley pairing states in honeycomb Dirac
  systems

abstract:
  Motivated by recent developments in the experimental study of superconducting
graphene and transition metal dichalcogenides, we investigate superconductivity
of the Kane-Mele (KM) model with short-range attractive interactions on the
two-dimensional honeycomb lattice. We show that intra-valley spin-triplet
pairing arises from nearest-neighbor (NN) attractive interaction and the
intrinsic spin-orbit coupling. We demonstrate this in two independent
approaches: We study superconducting instability driven by condensation of
Cooperons, which are in-gap bound states of two conduction electrons, within
the $T$-matrix approximation and also study the superconducting ground state
within the mean-field theory. We find that Cooperons with antiparallel spins
condense at the $K$ and $K'$ points. This leads to the emergence of an
intra-valley spin-triplet pairing state belonging to the irreducible
representation A$_1$ of the point group $C_{6v}$. The fact that this pairing
state has opposite chirality for $K$ and $K'$ identifies this state as a
"helical" valley-triplet state, the valley-analog to the $^3$He-B phase in two
dimension. Because of the finite center of mass momentum of Cooper pairs, the
pair amplitude in NN bonds exhibits spatial modulation on the length scale of
lattice constant, such that this pairing state may be viewed as a pair-density
wave state. We find that the pair amplitude spontaneously breaks the
translational symmetry and exhibits a $p$-Kekul\'e pattern. We also discuss the
selection rule for pairing states focusing the characteristic band structure of
the KM model and the Berry phase effects to the emergence of the intra-valley
pairing state.


title: Hadron rapidity spectra within a hybrid model

abstract:
  A 2-stage hybrid model is proposed that joins the fast initial state of
interaction, described by the hadron string dynamics (HSD) model, to subsequent
evolution of the expanding system at the second stage, treated within ideal
hydrodynamics. The developed hybrid model is assigned to describe heavy-ion
collisions in the energy range of the NICA collider under construction in
Dubna. Generally, the model is in reasonable agreement with the available data
on proton rapidity spectra. However, reproducing proton rapidity spectra, our
hybrid model cannot describe the rapidity distributions of pions. The model
should be improved by taking into consideration viscosity effects at the
hydrodynamical stage of system evolution.


title: Time averages in continuous time random walks

abstract:
  We investigate the time averaged squared displacement (TASD) of continuous
time random walks with respect to the number of steps $N$, which the random
walker performed during the data acquisition time $T$. We prove that the TASD,
and as well the apparent diffusion constant, grow linearly with $N$, provided
the steps possess a fourth moment and can not accumulate in small intervals.
Consequently, the fluctuations of the latter are dominated by the fluctuations
of $N$, and fluctuations of the walker's thermal history are irrelevant.
Furthermore, we show that the relative scatter decays as $1/\sqrt{N}$, which
suppresses all non-linear features in a plot of the TASD against the lag time.
Parts of our arguments also hold for continuous time random walks with
correlated steps.


title:
Electronic structure and phase transition in polar ScFeO3 from First
  Principles Calculations

abstract:
  The properties of newly discovered polar ScFeO3 with magnetic ordering are
examined using Ab initio calculations and symmetry mode analysis. The GGA+U
calculation confirms the stability of polar R3c Phase in ScFeO3 and the
pressure induced phase transition to non-polar Pnma phase. Octahedron tilting
and structural properties as a function of applied pressure have been analyzed.
The origin of polar phase is associated with instability of non-polar R-3c
phase and group theory using the symmetry mode analysis has been applied to
understand this instability as well as the spontaneous polarization of polar
R3c phase. The magnetic phase transition shows G-type AFM ordering of Fe3+ ion
within Goodenough-Kanamori theory and the possibility of magnetic spin
structure has been analyzed by using energy analysis including spin canting
possibility.


title:
Decameter Stationary Type IV Burst in Imaging Observations on the 6th of
  September 2014

abstract:
  First-of-its-kind radio imaging of decameter solar stationary type IV radio
burst has been presented in this paper. On 6 September 2014 the observations of
type IV burst radio emission have been carried out with the two-dimensional
heliograph based on the Ukrainian T-shaped radio telescope (UTR-2) together
with other telescope arrays. Starting at 09:55 UT and throughout 3 hours, the
radio emission was kept within the observational session of UTR-2. The
interesting observation covered the full evolution of this burst, "from birth
to death". During the event lifetime, two C-class solar X-ray flares with peak
times 11:29 UT and 12:24 UT took place. The time profile of this burst in radio
has a double-humped shape that can be explained by injection of energetic
electrons, accelerated by the two flares, into the burst source. According to
the heliographic observations we suggest the burst source was confined within a
high coronal loop, which was a part of a relatively slow coronal mass ejection.
The latter has been developed for several hours before the onset of the event.
Through analyzing about 1.5 million of heliograms (3700 temporal frames with
4096 images in each frame that correspond to the number of frequency channels)
the radio burst source imaging shows a fascinating dynamical evolution. Both
space-based (GOES, SDO, SOHO, STEREO) data and various ground-based
instrumentation (ORFEES, NDA, RSTO, NRH) records have been used for this study.


title:
Dynamic Modeling with Conditional Quantile Trajectories for Longitudinal
  Snippet Data, with Application to Cognitive Decline of Alzheimer's Patients

abstract:
  Longitudinal data are often plagued with sparsity of time points where
measurements are available. The functional data analysis perspective has been
shown to provide an effective and flexible approach to address this problem for
the case where measurements are sparse but their times are randomly distributed
over an interval. Here we focus on a different scenario where available data
can be characterized as snippets, which are very short stretches of
longitudinal measurements. For each subject the stretch of available data is
much shorter than the time frame of interest, a common occurrence in
accelerated longitudinal studies. An added challenge is introduced if a time
proxy that is basic for usual longitudinal modeling is not available. This
situation arises in the case of Alzheimer's disease and comparable scenarios,
where one is interested in time dynamics of declining performance, but the time
of disease onset is unknown and the chronological age does not provide a
meaningful time reference for longitudinal modeling. Our main methodological
contribution is to address this problem with a novel approach. Key quantities
for our approach are conditional quantile trajectories for monotonic processes
that emerge as solutions of a dynamic system, and for which we obtain uniformly
consistent estimates. These trajectories are shown to be useful to describe
processes that quantify deterioration over time, such as hippocampal volumes in
Alzheimer's patients.


title: Continuous-Time Quantum Walks on Directed Bipartite Graphs

abstract:
  This paper investigates continuous-time quantum walks on directed bipartite
graphs based on a graph's adjacency matrix. We prove that on bipartite graphs,
probability transport between the two node partitions can be completely
suppressed by tuning a model parameter $\alpha$. We provide analytic solutions
to the quantum walks for the star and circulant graph classes that are valid
for an arbitrary value of the number of nodes $N$, time $t$ and the model
parameter $\alpha$. We discuss quantitative and qualitative aspects of quantum
walks based on directed graphs and their undirected counterparts. Numerical
simulations of quantum walks on circulant graphs show complex interference
phenomena and how complete suppression of transport is achieved near
$\alpha=\pi/2$. By proving two mirror symmetries around $\alpha=0$ and $\pi/2$
we show that these quantum walks have a period of $\pi$ in $\alpha$. We show
that undirected edges lose their effect on the quantum walk at $\alpha=\pi/2$
and present non-bipartite graphs that exhibit suppression of transport.
Finally, we analytically compute the Hamiltonians of quantum walks on the
directed ring graph.


title: High rate, fast timing Glass RPC for the high $\eta$ CMS muon detectors

abstract:
  The HL-LHC phase is designed to increase by an order of magnitude the amount
of data to be collected by the LHC experiments. To achieve this goal in a
reasonable time scale the instantaneous luminosity would also increase by an
order of magnitude up to $6 \cdot 10^{34}$ cm$^{-2}$s$^{-1}$. The region of the
forward muon spectrometer ($|\eta| > 1.6$) is not equipped with RPC stations.
The increase of the expected particles rate up to 2 kHz/cm$^2$ ( including a
safety factor 3 ) motivates the installation of RPC chambers to guarantee
redundancy with the CSC chambers already present. The actual RPC technology of
CMS cannot sustain the expected background level. A new generation Glass-RPC
(GRPC) using low resistivity glass (LR) is proposed to equip at least the two
most far away of the four high eta muon stations of CMS. The design of small
size prototypes and the studies of their performances under high rate particles
flux is presented.


title: MUREN: delivering edge services in joint SDN-SDR multi-radio nodes

abstract:
  To meet the growing local and distributed computing needs, the cloud is now
descending to the network edge and sometimes to user equipments. This approach
aims at distributing computing, data processing, and networking services closer
to the end users. Instead of concentrating data and computation in a small
number of large clouds, many edge systems are envisioned to be deployed close
to the end users or where computing and intelligent networking can best meet
user needs. In this paper, we go further converging such massively distributed
computing systems with multiple radio accesses. We propose an architecture
called MUREN (Multi-Radio Edge Node) for managing traffic in future mobile edge
networks. Our solution is based on the Mobile Edge Cloud (MEC) architecture and
its close interaction with Software Defined Networking (SDN), the whole jointly
interacting with Software-Defined Radios (SDR). We have implemented our
architecture in a proof of concept and tested it with two edge scenarios. Our
experiments show that centralizing the intelligence in the MEC allows to
guarantee the requirements of the edge services either by adapting the waveform
parameters, or through changing the radio interface or even by reconfiguring
the applications. More generally, the best decision can be seen as the optimal
reaction to the wireless links variations


title:
Enhancing stability of correction procedure via reconstruction using
  summation-by-parts operators I: Artificial dissipation

abstract:
  The correction procedure via reconstruction (CPR, also known as flux
reconstruction) is a framework of high order semidiscretisations used for the
numerical solution of hyperbolic conservation laws. Using a reformulation of
these schemes relying on summation-by-parts (SBP) operators and simultaneous
approximation terms (SATs), artificial dissipation / spectral viscosity
operators are investigated in this first part of a series. Semidiscrete
stability results for linear advection and Burgers' equation as model problems
are extended to fully discrete stability by an explicit Euler method. As second
part of this series, Glaubitz, Ranocha, \"Offner, and Sonar (Enhancing
stability of correction procedure via reconstruction using summation-by-parts
operators II: Modal filtering, 2016) investigate connections to modal filters
and their application instead of artificial dissipation.


title:
A Minimal Variance Estimator for the Cardinality of Big Data Set
  Intersection

abstract:
  In recent years there has been a growing interest in developing "streaming
algorithms" for efficient processing and querying of continuous data streams.
These algorithms seek to provide accurate results while minimizing the required
storage and the processing time, at the price of a small inaccuracy in their
output. A fundamental query of interest is the intersection size of two big
data streams. This problem arises in many different application areas, such as
network monitoring, database systems, data integration and information
retrieval. In this paper we develop a new algorithm for this problem, based on
the Maximum Likelihood (ML) method. We show that this algorithm outperforms all
known schemes and that it asymptotically achieves the optimal variance.


title:
The granularity effect in amorphous InGaZnO$_4$ films prepared by rf
  sputtering method

abstract:
  We systematically investigated the temperature behaviors of the electrical
conductivity and Hall coefficient of two series of amorphous indium gallium
zinc oxides (a-IGZO) films prepared by rf sputtering method. The two series of
films are $\sim$700\,nm and $\sim$25\,nm thick, respectively. For each film,
the conductivity increases with decreasing temperature from 300\,K to $T_{\rm
max}$, where $T_{\rm max}$ is the temperature at which the conductivity reaches
its maximum. Below $T_{\rm max}$, the conductivity decreases with decreasing
temperature. Both the conductivity and Hall coefficient vary linearly with $\ln
T$ at low temperature regime. The $\ln T$ behaviors of conductivity and Hall
coefficient cannot be explained by the traditional electron-electron
interaction theory, but can be quantitatively described by the current
electron-electron theory due to the presence of granularity. Combining with the
scanning electron microscopy images of the films, we propose that the
boundaries between the neighboring a-IGZO particles could make the film
inhomogeneous and play an important role in the electron transport processes.


title:
An EV Charging Scheduling Mechanism to Maximize User Convenience and
  Cost Efficiency

abstract:
  This paper studies charging scheduling problem of electric vehicles (EVs) in
the scale of a microgrid (e.g., a university or town) where a set of charging
stations are controlled by a central aggregator. A bi-objective optimization
problem is formulated to jointly optimize total charging cost and user
convenience. Then, a close-to-optimal online scheduling algorithm is proposed
as solution. The algorithm achieves optimal charging cost and is near optimal
in terms of user convenience. Moreover, the proposed method applies an
efficient load forecasting technique to obtain future load information. The
algorithm is assessed through simulation and compared to the previous studies.
The results reveal that our method not only improves previous alternative
methods in terms of Pareto-optimal solution of the bi-objective optimization
problem, but also provides a close approximation for the load forecasting.


title: Rare decays of b hadrons

abstract:
  Rare decays of b hadrons provide a powerful way of identifying contributions
from physics beyond the Standard Model, in particular from new hypothetical
particles too heavy to be produced at colliders. The most relevant experimental
measurements are reviewed and possible interpretations are briefly discussed.


title:
Bethe/Gauge correspondence in odd dimension: modular double,
  non-perturbative corrections and open topological strings

abstract:
  Bethe/Gauge correspondence as it is usually stated is ill-defined in five
dimensions and needs a "non-perturbative" completion; a related problem also
appears in three dimensions. It has been suggested that this problem, probably
due to incompleteness of Omega background regularization in odd dimension, may
be solved if we consider gauge theory on compact $S^5$ and $S^3$ geometries. We
will develop this idea further by giving a full Bethe/Gauge correspondence
dictionary on $S^5$ and $S^3$ focussing mainly on the eigenfunctions of (open
and closed) relativistic 2-particle Toda chain and its quantized spectral
curve: these are most properly written in terms of non-perturbatively completed
NS open topological strings. A key ingredient is Faddeev's modular double
structure which is naturally implemented by the $S^5$ and $S^3$ geometries.


title:
On Recognizing Transparent Objects in Domestic Environments Using Fusion
  of Multiple Sensor Modalities

abstract:
  Current object recognition methods fail on object sets that include both
diffuse, reflective and transparent materials, although they are very common in
domestic scenarios. We show that a combination of cues from multiple sensor
modalities, including specular reflectance and unavailable depth information,
allows us to capture a larger subset of household objects by extending a state
of the art object recognition method. This leads to a significant increase in
robustness of recognition over a larger set of commonly used objects.


title:
Short-distance charmonium correlator on the lattice with M\"obius
  domain-wall fermion and a determination of charm quark mass

abstract:
  We calculate charmonium correlators on the lattice with 2+1-flavors of sea
quarks and charm valence quark both described by the M\"obius domain-wall
fermion. Temporal moments of the correlators are calculated and matched to
perturbative QCD formulae to extract the charm quark mass $m_c(\mu)$ and strong
coupling constant $\alpha_s(\mu)$. Lattice data at three lattice spacings,
0.044, 0.055, and 0.080~fm, are extrapolated to the continuum limit. The
correlators in the vector channel are confirmed to be consistent with the
experimental data for $e^+e^-\to c\bar{c}$, while the pseudo-scalar channel is
used to extract $m_c(\mu)$ and $\alpha_s(\mu)$. We obtain $m_\mathrm{c}(3
\mathrm{\ GeV})$ = 1.003(10)~GeV and
$\alpha_s^{\bar{\mathrm{MS}}(4)}(3\mathrm{\ GeV})$ = 0.253(13). Dominant source
of the error is the truncation of perturbative expansion at $\alpha_s^3$.


title: Detection of unresolved binaries with multicolor photometry

abstract:
  The principal goal of this paper is to specify conditions of detection of
unresolved binaries by multicolor photometry. We have developed a method for
estimating the critical distance at which an unresolved binary of given mass
and age can be detected. The method is applied to the photometric system of the
planned Lyra-B spaceborne experiment. We have shown that some types of
unresolved binary stars can be discovered and distinguished from single stars
solely by means of photometric observations.


title: On multivariable cumulant polynomial sequences with applications

abstract:
  A new family of polynomials, called cumulant polynomial sequence, and its
extensions to the multivariate case is introduced relied on a purely symbolic
combinatorial method. The coefficients of these polynomials are cumulants, but
depending on what is plugged in the indeterminates, either sequences of moments
either sequences of cumulants can be recovered. The main tool is a formal
generalization of random sums, also with a multivariate random index and not
necessarily integer-valued. Applications are given within parameter
estimations, L\'evy processes and random matrices and, more generally, problems
involving multivariate functions. The connection between exponential models and
multivariable Sheffer polynomial sequences offers a different viewpoint in
characterizing these models. Some open problems end the paper.


title:
How scaling of the disturbance set affects robust positively invariant
  sets for linear systems

abstract:
  This paper presents new results on robust positively invariant (RPI) sets for
linear discrete-time systems with additive disturbances. In particular, we
study how RPI sets change with scaling of the disturbance set. More precisely,
we show that many properties of RPI sets crucially depend on a unique scaling
factor which determines the transition from nonempty to empty RPI sets. We
characterize this critical scaling factor, present an efficient algorithm for
its computation, and analyze it for a number of examples from the literature.


title:
Dibaryons with two strange quarks and one heavy flavor in a constituent
  quark model

abstract:
  We investigate the symmetry property and the stability of dibaryons
containing two strange quarks and one heavy flavor with $I=\frac{1}{2}$. We
construct the wave function of the dibaryon in two ways. First, we directly
construct the color and spin state of the dibaryon starting from the four
possible SU(3) flavor state. Second, we consider the states composed of five
light quarks, and then construct the wave function of the dibaryon by adding
one heavy quark. The stability of the dibaryon against the strong decay into
two baryons is discussed by using variational method in a constituent quark
model with confining and hyperfine potential. We find that for all
configurations with S=0,1,2, the ground states of the dibaryons are the sum of
two baryons, and there are no compact bound state that is stable against the
strong decay.


title:
A revisit to the large-time behavior of the Vlasov/compressible
  Navier-Stokes equations

abstract:
  We establish the large-time behavior for the coupled kinetic-fluid equations.
More precisely, we consider the Vlasov equation coupled to the compressible
isentropic Navier-Stokes equations through a drag forcing term. For this
system, the large-time behavior shows the exponential alignment between
particles and fluid velocities as time evolves. This improves the previous
result by Bae-Choi-Ha-Kang[Disc. Cont. Dyn. Sys. A, 34, (2014), 4419--4458] in
which they considered the Vlasov/Navier-Stokes equations with nonlocal velocity
alignment forces for particles. Employing a new Lyapunov functional measuring
the fluctuations of momentum and mass from the averaged quantities, we refine
assumptions for the large-time behavior of the solutions to that system.


title: Seesaw model and two zero flavor neutrino texture

abstract:
  In the two zero flavor neutrino mass matrix scheme with nonvanishing Majorana
effective mass $M_{ee}$ for the neutrino less double beta decay, four textures
are compatible with observed data. We obtain the complete list of the possible
textures of four zero Dirac neutrino mass matrix $m_D$ in the seesaw mechanism
providing these four flavor neutrino textures. Explicit analytical analysis of
$m_D$ turns out to provide the relation of $m_D \propto \sqrt{M_{ee}}$.


title:
Pseudo minimum phi-divergence estimator for multinomial logistic
  regression with complex sample design

abstract:
  This article develops the theoretical framework needed to study the
multinomial logistic regression model for complex sample design with pseudo
minimum phi-divergence estimators. Through a numerical example and simulation
study new estimators are proposed for the parameter of the logistic regression
model with overdispersed multinomial distributions for the response variables,
the pseudo minimum Cressie-Read divergence estimators, as well as new
estimators for the intra-cluster correlation coefficient. The results show that
the Binder's method for the intra-cluster correlation coefficient exhibits an
excellent performance when the pseudo minimum Cressie-Read divergence
estimator, with lambda = 2/3 , is plugged.


title:
Automated Road Traffic Congestion Detection and Alarm Systems:
  Incorporating V2I communications into ATCSs

abstract:
  In this position paper, we address the problems of automated road congestion
detection and alerting systems and their security properties. We review
different theoretical adaptive road traffic control approaches, and three
widely deployed adaptive traffic control systems (ATCSs), namely, SCATS, SCOOT
and InSync. We then discuss some related research questions, and the
corresponding possible approaches, as well as the adversary model and potential
attack scenarios. Two theoretical concepts of automated road congestion alarm
systems (including system architecture, communication protocol, and algorithms)
are proposed on top of ATCSs, such as SCATS, SCOOT and InSync, by incorporating
secure wireless vehicle-to-infrastructure (V2I) communications. Finally, the
security properties of the proposed system have been discussed and analysed
using the ProVerif protocol verification tool.


title:
Subtraction of correlated noise in global networks of gravitational-wave
  interferometers

abstract:
  The recent discovery of merging black holes suggests that a stochastic
gravitational-wave background is within reach of the advanced detector network
operating at design sensitivity. However, correlated magnetic noise from
Schumann resonances threatens to contaminate observation of a stochastic
background. In this paper, we report on the first effort to eliminate
intercontinental correlated noise from Schumann resonances using Wiener
filtering. Using magnetometers as proxies for gravitational-wave detectors, we
demonstrate as much as a factor of two reduction in the coherence between
magnetometers on different continents. While much work remains to be done, our
results constitute a proof-of-principle and motivate follow-up studies with a
dedicated array of magnetometers.


title:
Synthesis, phase stability, structural and physical properties of
  11-type iron chalcogenides

abstract:
  This article reviews recent experimental investigations on two binary
Fe-chalcogenides: FeSe and Fe$_{1+y}$Te. The main focus is on synthesis, single
crystal growth, chemical composition, as well as on the effect of excess iron
on structural, magnetic, and transport properties of these materials. The
structurally simplest Fe-based superconductor Fe$_{1+x}$Se with a critical
temperature $T_c \approx$ 8.5 K undergoes a tetragonal to orthorhombic phase
transition at a temperature $T_s \approx$ 87 K. No long-range magnetic order is
observed down to the lowest measured temperature in Fe$_{1+x}$Se. On the other
hand, isostructural Fe$_{1+y}$Te displays a complex interplay of magnetic and
structural phase transitions in dependence on the tuning parameter such as
excess amount of Fe or pressure, but it becomes a superconductor only when Te
is substituted by a sufficient amount of Se. We summarize experimental evidence
for different competing interactions and discuss related open questions.


title: The Ascoli property for function spaces

abstract:
  The paper deals with Ascoli spaces $C_p(X)$ and $C_k(X)$ over Tychonoff
spaces $X$. The class of Ascoli spaces $X$, i.e. spaces $X$ for which any
compact subset $K$ of $C_k(X)$ is evenly continuous, essentially includes the
class of $k_{\mathbb R}$-spaces. First we prove that if $C_p(X)$ is Ascoli,
then it is $\kappa$-Fr\'echet-Urysohn. If $X$ is cosmic, then $C_p(X)$ is
Ascoli iff it is $\kappa$-Fr'echet-Urysohn. This leads to the following
extension of a result of Morishita: If for a \v{C}ech-complete space $X$ the
space $C_p(X)$ is Ascoli, then $X$ is scattered. If $X$ is scattered and
stratifiable, then $C_p(X)$ is an Ascoli space. Consequently: (a) If $X$ is a
complete metrizable space, then $C_p(X)$ is Ascoli iff $X$ is scattered. (b) If
$X$ is a \v{C}ech-complete Lindel\"of space, then $C_p(X)$ is Ascoli iff $X$ is
scattered iff $C_p(X)$ is Fr\'echet-Urysohn. Moreover, we prove that for a
paracompact space $X$ of point-countable type the following conditions are
equivalent: (i) $X$ is locally compact. (ii) $C_k(X)$ is a $k_{\mathbb
R}$-space. (iii) $C_k(X)$ is an Ascoli space. The Asoli spaces $C_k(X,[0,1])$
are also studied.


title: Model Checking : A Co-algebraic Approach

abstract:
  State explosion problem is the main obstacle of model checking. In this
paper, we try to solve this problem from a coalgebraic approach. We establish
an effective method to prove uniformly the existence of the smallest Kripke
structure with respect to bisimilarity, which describes all behaviors of the
Kripke structures and no redundancy. We show then this smallest Kripke
structure generates a concrete smallest one for each given finite Kripke
structure and some kind of infinite ones. This method is based on the existence
of the final coalgebra of a suitable endofunctor and can be generalized
smoothly to other coalgebraic structures. A naive implementation of this method
is developed in Ocaml.


title:
Selecting the Best Player Formation for Corner-Kick Situations Based on
  Bayes' Estimation

abstract:
  In the domain of the Soccer simulation 2D league of the RoboCup project,
appropriate player positioning against a given opponent team is an important
factor of soccer team performance. This work proposes a model which decides the
strategy that should be applied regarding a particular opponent team. This task
can be realized by applying preliminary a learning phase where the model
determines the most effective strategies against clusters of opponent teams.
The model determines the best strategies by using sequential Bayes' estimators.
As a first trial of the system, the proposed model is used to determine the
association of player formations against opponent teams in the particular
situation of corner-kick. The implemented model shows satisfying abilities to
compare player formations that are similar to each other in terms of
performance and determines the right ranking even by running a decent number of
simulation games.


title: On Coupling Particle Filter Trajectories

abstract:
  Particle filters are a powerful and flexible tool for performing inference on
state-space models. They involve a collection of samples evolving over time
through a combination of sampling and re-sampling steps. The re-sampling step
is necessary to ensure that weight degeneracy is avoided. In several situations
of statistical interest, it is important to be able to compare the estimates
produced by two different particle filters; consequently, being able to
efficiently couple two particle filter trajectories is often of paramount
importance. In this text, we propose several ways to do so. In particular, we
leverage ideas from the optimal transportation literature. In general, though,
computing the optimal transport map is extremely computationally expensive; to
deal with this, we introduce computationally tractable approximations to
optimal transport couplings. We demonstrate that our resulting algorithms for
coupling two particle filter trajectories often perform orders of magnitude
more efficiently than more standard approaches.


title:
Combining EEG source connectivity and network similarity: Application to
  object categorization in the human brain

abstract:
  A major challenge in cognitive neuroscience is to evaluate the ability of the
human brain to categorize or group visual stimuli based on common features.
This categorization process is very fast and occurs in few hundreds of
millisecond time scale. However, an accurate tracking of the spatiotemporal
dynamics of large-scale brain networks is still an unsolved issue. Here, we
show the combination of recently developed method called dense-EEG source
connectivity to identify functional brain networks with excellent temporal and
spatial resolutions and an algorithm, called SimNet, to compute brain networks
similarity. Two categories of visual stimuli were analysed in this study:
immobile and mobile. Networks similarity was assessed within each category
(intra-condition) and between categories (inter-condition). Results showed high
similarity within each category and low similarity between the two categories.
A significant difference between similarities computed in the intra and
inter-conditions was observed at the period of 120-190ms supposed to be related
to visual recognition and memory access. We speculate that these observations
will be very helpful toward understanding the object categorization in the
human brain from a network perspective.


title: Integrable boundary conditions for multi-species ASEP

abstract:
  The first result of the present paper is to provide classes of explicit
solutions for integrable boundary matrices for the multi-species ASEP with an
arbitrary number of species.
  All the solutions we have obtained can be seen as representations of a new
algebra that contains the boundary Hecke algebra. The boundary Hecke algebra is
not sufficient to build these solutions. This is the second result of our
paper.


title:
An intrinsic square function on weighted Herz spaces with variable
  exponent

abstract:
  We define new generalized Herz spaces having weight and variable exponent,
that is, weighted Herz spaces with variable exponent. We prove the boundedness
of an intrinsic square function on those spaces under proper assumptions on
each exponent and weight.


title:
A FEM approximation of a two-phase obstacle problem and its a posteriori
  error estimate

abstract:
  This paper is concerned with the two--phase obstacle problem, a type of a
variational free boundary problem. We recall the basic estimates of Repin and
Valdman (2015) and verify them numerically on two examples in two space
dimensions. A solution algorithm is proposed for the construction of the finite
element approximation to the two--phase obstacle problem. The algorithm is not
based on the primal (convex and nondifferentiable) energy minimization problem
but on a dual maximization problem formulated for Lagrange multipliers. The
dual problem is equivalent to a quadratic programming problem with box
constraints. The quality of approximations is measured by a functional a
posteriori error estimate which provides a guaranteed upper bound of the
difference of approximated and exact energies of the primal minimization
problem. The majorant functional in the upper bound contains auxiliary
variables and it is optimized with respect to them to provide a sharp upper
bound. A space density of the nonlinear related part of the majorant functional
serves as an indicator of the free boundary.


title: Automatic Separation of Compound Figures in Scientific Articles

abstract:
  Content-based analysis and retrieval of digital images found in scientific
articles is often hindered by images consisting of multiple subfigures
(compound figures). We address this problem by proposing a method to
automatically classify and separate compound figures, which consists of two
main steps: (i) a supervised compound figure classifier (CFC) discriminates
between compound and non-compound figures using task-specific image features;
and (ii) an image processing algorithm is applied to predicted compound images
to perform compound figure separation (CFS). Our CFC approach is shown to
achieve state-of-the-art classification performance on a published dataset. Our
CFS algorithm shows superior separation accuracy on two different datasets
compared to other known automatic approaches. Finally, we propose a method to
evaluate the effectiveness of the CFC-CFS process chain and use it to optimize
the misclassification loss of CFC for maximal effectiveness in the process
chain.


title: The Arithmetic of Supersymmetric Vacua

abstract:
  We provide explicit formulas for the number of vacua of four-dimensional pure
N=1 super Yang-Mills theories on a circle, with any simple gauge algebra and
any choice of center and spectrum of line operators. These form a key
ingredient in the semi-classical calculation of the number of massive vacua of
N=1* gauge theories with gauge algebra su(n) compactified on a circle. Using
arithmetic, we express that number in an SL(2,Z) duality invariant manner. We
confirm our tally of massive vacua of the N=1* theories by a count of
inequivalent extrema of the exact superpotential. Furthermore, we compute a
formula for a refined index that distinguishes massive vacua according to their
unbroken discrete gauge group.


title:
Asymptotic analysis of a Vlasov-Boltzmann equation with anomalous
  scaling

abstract:
  This paper is devoted to the approximation of the linear Boltzmann equation
by fractional diffusion equations. Most existing results address this question
when there is no external acceleration field. The goal of this paper is to
investigate the case where a given acceleration field is present. The main
result of this paper shows that for an appropriate scaling of the acceleration
field, the usual fractional diffusion equation is supplemented by an advection
term. Both the critical and supercritical case are considered.


title:
Stability for weighted composition $C_0$-semigroups on Lebesgue and
  Sobolev spaces

abstract:
  Stability of weighted composition strongly continuous semigroups acting on
Lebesgue and Sobolev spaces is studied, without the use of spectral conditions
on the generator of the semigroup. Applications to the generalized von Foerster
- Lasota semigroup and a comparison with hypercylicity conditions are
presented.\


title: Penalized Barycenters in the Wasserstein Space

abstract:
  In this paper, a regularization of Wasserstein barycenters for random
measures supported on $\mathbb{R}^{d}$ is introduced via convex penalization.
The existence and uniqueness of such barycenters is first proved for a large
class of penalization functions. The Bregman divergence associated to the
penalization term is then considered to obtain a stability result on penalized
barycenters. This allows the comparison of data made of $n$ absolutely
continuous probability measures, within the more realistic setting where one
only has access to a dataset of random variables sampled from unknown
distributions. The convergence of the penalized empirical barycenter of a set
of $n$ iid random probability measures towards its population counterpart is
finally analyzed. This approach is shown to be appropriate for the statistical
analysis of either discrete or absolutely continuous random measures. It also
allows to construct, from a set of discrete measures, consistent estimators of
population Wasserstein barycenters that are absolutely continuous.


title: NP-completeness in the gossip monoid

abstract:
  Gossip monoids form an algebraic model of networks with exclusive, transient
connections in which nodes, when they form a connection, exchange all known
information. They also arise naturally in pure mathematics, as the monoids
generated by the set of all equivalence relations on a given finite set under
relational composition. We prove that a number of important decision problems
for these monoids (including the membership problem, and hence the problem of
deciding whether a given state of knowledge can arise in a network of the kind
under consideration) are NP-complete. As well as being of interest in their own
right, these results shed light on the apparent difficulty of establishing the
cardinalities of the gossip monoids: a problem which has attracted some
attention in the last few years.


title: Pointwise Gradient Bounds for Degenerate Semigroups (of UFG type)

abstract:
  In this paper we consider diffusion semigroups generated by second order
differential operators of degenerate type. The operators that we consider do
not, in general, satisfy the Hormander condition and are not hypoelliptic. In
particular, instead of working under the Hormander paradigm, we consider the
so-called UFG condition, introduced by Kusuoka and Strook in the eighties. The
UFG condition is weaker than the uniform Hormander condition, the smoothing
effect taking place only in certain directions (rather than in every direction,
as it is the case when the Hormander condition is assumed). Under the UFG
condition, Kusuoka and Strook deduced sharp small time asymptotic bounds for
the derivatives of the semigroup in the directions where smoothing occurs. In
this paper, we study the large time asymptotics for the gradients of the
diffusion semigroup in the same set of directions and under the same UFG
condition. In particular, we identify conditions under which the derivatives of
the diffusion semigroup in the smoothing directions decay exponentially in
time. This paper constitutes therefore a stepping stone in the analysis of the
long time behaviour of diffusions which do not satisfy the Hormander
condition.


title:
Characterizing and Finding the Pareto Optimal Equitable Allocation of
  Homogeneous Divisible Goods Among Three Players

abstract:
  We consider the division of a finite number of homogeneous divisible items
among three players. Under the assumption that each player assigns a positive
value to every item, we characterize the optimal allocations and we develop two
exact algorithms for its search. Both the characterization and the algorithm
are based on the tight relationship two geometric objects of fair division: the
Individual Pieces Set (IPS) and the Radon-Nykodim Set (RNS).


title: G-bundles on the absolute Fargues-Fontaine curve

abstract:
  We prove that the category of vector bundles on the absolute Fargues-Fontaine
curve is canonically equivalent to the category of isocrystals. We deduce a
similar result for G-bundles for some arbitrary reductive group G over a p-adic
local field.


title: Surface-effect corrections for the solar model

abstract:
  Solar p-mode oscillations exhibit a systematic offset towards higher
frequencies due to shortcomings in the 1D stellar structure models, especially,
the lack of turbulent pressure in the superadiabatic layers just below the
optical surface, arising from the convective velocity field. We study the
influence of the turbulent expansion, chemical composition, and magnetic fields
on the stratification in the upper layers of the solar models in comparison
with solar observations. Furthermore, we test alternative <3D> averages for
improved results on the oscillation frequencies. We appended temporally and
spatially averaged <3D> stratifications to 1D models to compute adiabatic
oscillation frequencies that we then tested against observations. We also
developed depth-dependent corrections for the solar 1D model, for which we
expanded the geometrical depth to match the pressure stratification of the
solar <3D> model, and we reduced the density that is caused by the turbulent
pressure. We obtain the same results with our <3D> models as have been reported
previously. Our depth-dependent corrected 1D models match the observations to
almost a similar extent as the <3D> model. We find that correcting for the
expansion of the geometrical depth and the reducing of the density are both
equally necessary. Interestingly, the influence of the adiabatic exponent Gam1
is less pronounced than anticipated. The turbulent elevation directly from the
<3D> model does not match the observations properly. Considering different
reference depth scales for the <3D> averaging leads to very similar
frequencies. Solar models with high metal abundances in their initial chemical
composition match the low-frequency part much better. We find a linear relation
between the p-mode frequency shift and the vertical magnetic field strength
with dvnl = 26.21Bz microHz/kG, which is able to render the solar activity
cycles correctly.


title:
Superconducting switch for fast on-chip routing of quantum microwave
  fields

abstract:
  A switch capable of routing microwave signals at cryogenic temperatures is a
desirable component for state-of-the-art experiments in many fields of applied
physics, including but not limited to quantum information processing,
communication and basic research in engineered quantum systems. Conventional
mechanical switches provide low insertion loss but disturb operation of
dilution cryostats and the associated experiments by heat dissipation. Switches
based on semiconductors or microelectromechanical systems have a lower thermal
budget but are not readily integrated with current superconducting circuits.
Here we design and test an on-chip switch built by combining tunable
transmission-line resonators with microwave beam-splitters. The device is
superconducting and as such dissipates a negligible amount of heat. It is
compatible with current superconducting circuit fabrication techniques,
operates with a bandwidth exceeding $100\,\mathrm{MHz}$, is capable of handling
photon fluxes on the order of $10^{5}\,\mu\mathrm{s}^{-1}$, equivalent to
powers exceeding $-90\,\mathrm{dBm}$, and can be switched within approximately
$6-8\,\mathrm{ns}$. We successfully demonstrate operation of the device in the
quantum regime by integrating it on a chip with a single-photon source and
using it to route non-classical itinerant microwave fields at the single-photon
level.


title: A solar-like magnetic cycle on the mature K-dwarf 61 Cyg A (HD 201091)

abstract:
  The long-term monitoring of magnetic cycles in cool stars is a key diagnostic
in understanding how dynamo generation and amplification of magnetic fields
occur in stars similar in structure to the Sun. We investigate the temporal
evolution of a possible magnetic cycle, determined from its large-scale field,
of 61 Cyg A over its activity cycle using spectropolarimetric observations and
compare it to the solar case. We use Zeeman Doppler imaging (ZDI) to
reconstruct the large-scale magnetic geometry over multiple observational
epochs spread over a time span of nine years. We investigate the time evolution
of the different components of the large-scale field and compare it with the
evolution of its chromospheric activity by measuring the flux in three
different chromospheric indicators: Ca II H&K, H-alpha and Ca II infra red
triplet lines. We also compare our results with the star's coronal activity
using XMM-Newton observations. The large-scale magnetic geometry of 61 Cyg A
exhibits polarity reversals in both poloidal and toroidal field components, in
phase with the chromospheric activity cycle. We also detect weak solar-like
differential rotation with a shear level similar to the Sun. During our
observational time span of nine years, 61 Cyg A exhibits solar-like variations
in its large-scale field geometry as it evolves from minimum activity to
maximum activity and vice versa. During its activity minimum in epoch 2007.59,
ZDI reconstructs a simple dipolar geometry which becomes more complex close to
activity maximum in epoch 2010.55. The radial field flips polarity and reverts
back to a simple geometry in epoch 2013.61. The field is strongly dipolar and
the evolution of the dipole component of the field is reminiscent of the solar
behaviour. The polarity reversal of the large-scale field indicates a magnetic
cycle that is in phase with the chromospheric and coronal cycle.