title:
How hot is .brussels? Impact of the uptake of the .brussels top-level
  domain name extension

abstract:
  The opening up of the top-level domain name market in 2012 has offered new
perspectives for companies, administrations and individuals to include a
geographic component within the domain name of their website. Little to no
research has been carried out since then to analyse the uptake of the new
top-level domain names (TLDN). Based on the specific case of the TLDN
.brussels, this article proposes an empirical study of how the opening up of
the top-level domain name market actually impacts registration practices. By
making use of freely available software tools such as OpenRefine and Natural
Language Processing (NLP) methods, the entire corpus of the .brussels domain
names (6300) was analysed from a quantitative perspective. Based on a
statistically representative sample, a qualitative interpretation allowed for a
more fine-grained analysis of how the new TLDN is being used in practice. By
doing so, the article gives a detailed insight into the impact of the recent
changes of the rules concerning domain name registration. Researchers, policy
makers, investors and anyone who cares about the Brussels identity in the
digital realm can gain through this analysis a better understanding of the
state of play of the .brussels TLDN.


title:
Exact and efficient top-K inference for multi-target prediction by
  querying separable linear relational models

abstract:
  Many complex multi-target prediction problems that concern large target
spaces are characterised by a need for efficient prediction strategies that
avoid the computation of predictions for all targets explicitly. Examples of
such problems emerge in several subfields of machine learning, such as
collaborative filtering, multi-label classification, dyadic prediction and
biological network inference. In this article we analyse efficient and exact
algorithms for computing the top-$K$ predictions in the above problem settings,
using a general class of models that we refer to as separable linear relational
models. We show how to use those inference algorithms, which are modifications
of well-known information retrieval methods, in a variety of machine learning
settings. Furthermore, we study the possibility of scoring items incompletely,
while still retaining an exact top-K retrieval. Experimental results in several
application domains reveal that the so-called threshold algorithm is very
scalable, performing often many orders of magnitude more efficiently than the
naive approach.


title: Cross-Lingual Morphological Tagging for Low-Resource Languages

abstract:
  Morphologically rich languages often lack the annotated linguistic resources
required to develop accurate natural language processing tools. We propose
models suitable for training morphological taggers with rich tagsets for
low-resource languages without using direct supervision. Our approach extends
existing approaches of projecting part-of-speech tags across languages, using
bitext to infer constraints on the possible tags for a given word type or
token. We propose a tagging model using Wsabie, a discriminative
embedding-based model with rank-based learning. In our evaluation on 11
languages, on average this model performs on par with a baseline
weakly-supervised HMM, while being more scalable. Multilingual experiments show
that the method performs best when projecting between related language pairs.
Despite the inherently lossy projection, we show that the morphological tags
predicted by our models improve the downstream performance of a parser by +0.6
LAS on average.


title: A Normalized Sunspot-Area Series Starting in 1832: an Update

abstract:
  A new normalized sunspot-area series has been reconstructed from the series
obtained by the Royal Greenwich Observatory and other contemporary institutions
for the period 1874 - 2008 and the area series compiled by De la Rue, Stewart,
and Loewy from 1832 to 1868. Since the two sets of series do not overlap in
time, we used as a link between them the new version of sunspot index number
(Version 2) published by SILSO (Sunspot Index and Long-term Solar
Observations). We also present a spectral analysis of the normalized area
series in search of periodicities beyond the well-known solar cycle of 11 years
and a study of the Waldmeier effect in the new version of sunspot-number and
the sunspot-area series presented in this study. We conclude that while this
effect is significant in the new series of sunspot number, it has a weak
relationship with the sunspot-area series.


title: Level-$\delta$ limit linear series

abstract:
  We introduce the notion of level-$\delta$ limit linear series, which describe
limits of linear series along families of smooth curves degenerating to a
singular curve $X$. We treat here only the simplest case where $X$ is the union
of two smooth components meeting transversely at a point $P$. The integer
$\delta$ stands for the singularity degree of the total space of the
degeneration at $P$. If the total space is regular, we get level-1 limit linear
series, which are precisely those introduced by Osserman in 2006. We construct
a projective moduli space $G^r_{d,\delta}(X)$ parameterizing level-$\delta$
limit linear series of rank $r$ and degree $d$ on $X$, and show that it is a
new compactification, for each $\delta$, of the moduli space of Osserman exact
limit linear series, an open subscheme $G^{r,*}_{d,1}(X)$ of the space
$G^r_{d,1}(X)$ already constructed by Osserman. Finally, we generalize work by
Esteves and Osserman by associating to each exact level-$\delta$ limit linear
series $\mathfrak g$ on $X$ a closed subscheme $\mathbb P(\mathfrak g)\subseteq
X^{(d)}$ of the $d$th symmetric product of $X$, and showing that $\mathbb
P(\mathfrak g)$ is the limit of the spaces of divisors associated to linear
series on smooth curves degenerating to $\mathfrak g$ on $X$, if such
degenerations exist. In particular, we describe completely limits of divisors
along degenerations to such a curve $X$.


title:
Myrmics: Scalable, Dependency-aware Task Scheduling on Heterogeneous
  Manycores

abstract:
  Task-based programming models have become very popular, as they offer an
attractive solution to parallelize serial application code with task and data
annotations. They usually depend on a runtime system that schedules the tasks
to multiple cores in parallel while resolving any data hazards. However,
existing runtime system implementations are not ready to scale well on emerging
manycore processors, as they often rely on centralized structures and/or locks
on shared structures in a cache-coherent memory. We propose design choices,
policies and mechanisms to enhance runtime system scalability for single-chip
processors with hundreds of cores. Based on these concepts, we create and
evaluate Myrmics, a runtime system for a dependency-aware, task-based
programming model on a heterogeneous hardware prototype platform that emulates
a single-chip processor of 8 latency-optimized and 512 throughput-optimized
CPUs. We find that Myrmics scales successfully to hundreds of cores. Compared
to MPI versions of the same benchmarks with hand-tuned message passing, Myrmics
achieves similar scalability with a 10-30% performance overhead, but with less
programming effort. We analyze the scalability of the runtime system in detail
and identify the key factors that contribute to it.


title:
Convergence to suitable weak solutions for a finite element
  approximation of the Navier-Stokes equations with numerical subgrid scale
  modeling

abstract:
  In this work we prove that weak solutions constructed by a variational
multiscale method are suitable in the sense of Scheffer. In order to prove this
result, we consider a subgrid model that enforces orthogonality between subgrid
and finite element components. Further, the subgrid component must be tracked
in time. Since this type of schemes introduce pressure stabilization, we have
proved the result for equal-order velocity and pressure finite element spaces
that do not satisfy a discrete inf-sup condition.


title: Antiferromagnetic spintronics

abstract:
  Antiferromagnetic materials could represent the future of spintronic
applications thanks to the numerous interesting features they combine: they are
robust against perturbation due to magnetic fields, produce no stray fields,
display ultrafast dynamics and are capable of generating large
magneto-transport effects. Intense research efforts over the past decade have
been invested in unraveling spin transport properties in antiferromagnetic
materials. Whether spin transport can be used to drive the antiferromagnetic
order and how subsequent variations can be detected are some of the thrilling
challenges currently being addressed. Antiferromagnetic spintronics started out
with studies on spin transfer, and has undergone a definite revival in the last
few years with the publication of pioneering articles on the use of spin-orbit
interactions in antiferromagnets. This paradigm shift offers possibilities for
radically new concepts for spin manipulation in electronics. Central to these
endeavors are the need for predictive models, relevant disruptive materials and
new experimental designs. This paper reviews the most prominent spintronic
effects described based on theoretical and experimental analysis of
antiferromagnetic materials. It also details some of the remaining bottlenecks
and suggests possible avenues for future research.


title:
Solving Backward Stochastic Differential Equations with quadratic-growth
  drivers by Connecting the Short-term Expansions

abstract:
  This article proposes a new approximation scheme for quadratic-growth BSDEs
in a Markovian setting by connecting a series of semi-analytic asymptotic
expansions applied to short-time intervals. Although there remains a condition
which needs to be checked a posteriori, one can avoid altogether time-consuming
Monte Carlo simulation and other numerical integrations for estimating
conditional expectations at each space-time node. Numerical examples of
quadratic-growth as well as Lipschitz BSDEs suggest that the scheme works well
even for large quadratic coefficients, and a fortiori for large Lipschitz
constants.


title:
Correlating CMB Spectral Distortions with Temperature: what do we learn
  on Inflation?

abstract:
  Probing correlations among short and long-wavelength cosmological
fluctuations is known to be decisive for deepening the current understanding of
inflation at the microphysical level. Spectral distortions of the CMB can be
caused by dissipation of cosmological perturbations when they re-enter Hubble
after inflation. Correlating spectral distortions with temperature anisotropies
will thus provide the opportunity to greatly enlarge the range of scales over
which squeezed limits can be tested, opening up a new window on inflation
complementing the ones currently probed with CMB and LSS. In this paper we
discuss a variety of inflationary mechanisms that can be efficiently
constrained with distortion-temperature correlations. For some of these
realizations (representative of large classes of models) we derive quantitative
predictions for the squeezed limit bispectra, finding that their amplitudes are
above the sensitivity limits of an experiment such as the proposed PIXIE.


title:
Business Matter Experts do Matter: A Model-Driven Approach for Domain
  Specific Process Design and Monitoring

abstract:
  Business process design and monitoring are essential elements of Business
Process Management (BPM), often relying on Service Oriented Architectures
(SOA). However the current BPM approaches and standards have not sufficiently
reduced the Business-IT gap. Today's solutions are mostly domain-independent
and platform-dependent, which limits the ability of business matter experts to
express business intent and enact process change. In contrast, the approach
presented in this paper focuses on BPM and SOA environments in a
domain-dependent and platform-independent way. We propose to add a domain
specific-layer on top of current solutions so business stakeholders can design
and understand their processes in a more intuitive way. We rely on previously
proposed technical solutions and integrate them in an end-to-end methodology
(from design to monitoring and back). The appropriateness and the feasibility
of the approach is justified through a use case and a complete prototype
implementation.


title: BDDT-SCC: A Task-parallel Runtime for Non Cache-Coherent Multicores

abstract:
  This paper presents BDDT-SCC, a task-parallel runtime system for non
cache-coherent multicore processors, implemented for the Intel Single-Chip
Cloud Computer. The BDDT-SCC runtime includes a dynamic dependence analysis and
automatic synchronization, and executes OpenMP-Ss tasks on a non cache-coherent
architecture. We design a runtime that uses fast on-chip inter-core
communication with small messages. At the same time, we use non coherent shared
memory to avoid large core-to-core data transfers that would incur a high
volume of unnecessary copying. We evaluate BDDT-SCC on a set of representative
benchmarks, in terms of task granularity, locality, and communication. We find
that memory locality and allocation plays a very important role in performance,
as the architecture of the SCC memory controllers can create strong contention
effects. We suggest patterns that improve memory locality and thus the
performance of applications, and measure their impact.


title: Automatic Text Scoring Using Neural Networks

abstract:
  Automated Text Scoring (ATS) provides a cost-effective and consistent
alternative to human marking. However, in order to achieve good performance,
the predictive features of the system need to be manually engineered by human
experts. We introduce a model that forms word representations by learning the
extent to which specific words contribute to the text's score. Using Long-Short
Term Memory networks to represent the meaning of texts, we demonstrate that a
fully automated framework is able to achieve excellent results over similar
approaches. In an attempt to make our results more interpretable, and inspired
by recent advances in visualizing neural networks, we introduce a novel method
for identifying the regions of the text that the model has found more
discriminative.


title:
Radiative and mechanical feedback into the molecular gas in the Large
  Magellanic Cloud. I. N159W

abstract:
  We present Herschel SPIRE Fourier Transform Spectrometer (FTS) observations
of N159W, an active star-forming region in the Large Magellanic Cloud (LMC). In
our observations, a number of far-infrared cooling lines including CO(4-3) to
CO(12-11), [CI] 609 and 370 micron, and [NII] 205 micron are clearly detected.
With an aim of investigating the physical conditions and excitation processes
of molecular gas, we first construct CO spectral line energy distributions
(SLEDs) on 10 pc scales by combining the FTS CO transitions with ground-based
low-J CO data and analyze the observed CO SLEDs using non-LTE radiative
transfer models. We find that the CO-traced molecular gas in N159W is warm
(kinetic temperature of 153-754 K) and moderately dense (H2 number density of
(1.1-4.5)e3 cm-3). To assess the impact of the energetic processes in the
interstellar medium on the physical conditions of the CO-emitting gas, we then
compare the observed CO line intensities with the models of photodissociation
regions (PDRs) and shocks. We first constrain the properties of PDRs by
modelling Herschel observations of [OI] 145, [CII] 158, and [CI] 370 micron
fine-structure lines and find that the constrained PDR components emit very
weak CO emission. X-rays and cosmic-rays are also found to provide a negligible
contribution to the CO emission, essentially ruling out ionizing sources
(ultraviolet photons, X-rays, and cosmic-rays) as the dominant heating source
for CO in N159W. On the other hand, mechanical heating by low-velocity C-type
shocks with ~10 km/s appears sufficient enough to reproduce the observed warm
CO.


title: R&D towards the CMS RPC Phase-2 upgrade

abstract:
  The high pseudo-rapidity region of the CMS muon system is covered by Cathode
Strip Chambers (CSC) only and lacks redundant coverage despite the fact that it
is a challenging region for muons in terms of backgrounds and momentum
resolution. In order to maintain good efficiency for the muon trigger in this
region additional RPCs are planned to be installed in the two outermost
stations at low angle named RE3/1 and RE4/1. These stations will use RPCs with
finer granularity and good timing resolution to mitigate background effects and
to increase the redundancy of the system.


title:
Numerical investigation of tuning method for nonuniform disk-loaded
  waveguides

abstract:
  On the base of more general model we assessed accuracy of method that is
widely used for post- tuning accelerator sections. Our consideration has shown
that for wide range of disk loaded waveguide (DLW) parameters using simple
tuning coefficients gives appropriate characteristics of DLWs. For injector
sections, in which phase velocity and amplitude change, there are some
deviation from the desired characteristics. It is necessary to evaluate the
influence of additional phase shift on beam characteristics at the injector
exit.


title: Computability of F{\o}lner sets

abstract:
  We define the notion of computability of F{\o}lner sets for finitely
generated amenable groups. We prove, by an explicit description, that the
Kharlampovich group, a finitely presented solvable group with unsolvable word
problem, has computable F{\o}lner sets. We also prove computability of
F{\o}lner sets for a group that is extension of an amenable group with solvable
word problem by a finitely generated group with computable F{\o}lner sets with
subrecursive distortion function. Moreover we obtain some known and some new
upper bounds for the F{\o}lner function in these particular extensions.


title: Fractional type integral operators on variable Hardy spaces

abstract:
  We study the boundedness of certain fractional integral operators from Hp(.)
into Lq(.). We also obtain the Hp(.)- Hq(.) boundedness of the Riesz potential.


title: Mechanical stability of bipolar spindle assembly

abstract:
  Assembly and stability of mitotic spindle is governed by the interplay of
various intra-cellular forces, e.g. the forces generated by motor proteins by
sliding overlapping anti-parallel microtubules (MTs) polymerized from the
opposite centrosomes, the interaction of kinetochores with MTs, and the
interaction of MTs with the chromosomes arms. We study the mechanical behavior
and stability of spindle assembly within the framework of a minimal model which
includes all these effects. For this model, we derive a closed--form analytical
expression for the force acting between the centrosomes as a function of their
separation distance and we show that an effective potential can be associated
with the interactions at play. We obtain the stability diagram of spindle
formation in terms of parameters characterizing the strength of motor sliding,
repulsive forces generated by polymerizing MTs, and the forces arising out of
interaction of MTs with kinetochores. The stability diagram helps in
quantifying the relative effects of the different interactions and elucidates
the role of motor proteins in formation and inhibition of spindle structures
during mitotic cell division. We also predict a regime of bistability for
certain parameter range, wherein the spindle structure can be stable for two
different finite separation distances between centrosomes. This occurrence of
bistability also suggests mechanical versatility of such self-assembled spindle
structures.


title: DiSquawk: 512 cores, 512 memories, 1 JVM

abstract:
  Trying to cope with the constantly growing number of cores per processor,
hardware architects are experimenting with modular non-cache-coherent
architectures. Such architectures delegate the memory coherency to the
software. On the contrary, high productivity languages, like Java, are designed
to abstract away the hardware details and allow developers to focus on the
implementation of their algorithm. Such programming languages rely on a process
virtual machine to perform the necessary operations to implement the
corresponding memory model. Arguing about the correctness of such
implementations is not trivial though.
  In this work we present our implementation of the Java Memory Model in a Java
Virtual Machine targeting a 512-core non-cache-coherent memory architecture. We
shortly discuss design decisions and present early evaluation results, which
demonstrate that our implementation scales with the number of cores. We model
our implementation as the operational semantics of a Java Core Calculus that we
extend with synchronization actions, and prove its adherence to the Java Memory
Model.


title:
Haldane insulator protected by reflection symmetry in the doped Hubbard
  model on the three-legged ladder

abstract:
  We demonstrate the existence of an insulating phase in the three-legged
Hubbard ladder at two-thirds filling. In this phase chargons are bound because
the physics within a unit cell favors the formation of triplets. The resultant
moments lead to a ground state in the Haldane phase, a symmetry protected
topological state of matter. In this purely fermionic model, reflection is
protecting but time reversal and dihedral symmetries are not, in contrast to
spin models.


title:
Binding equilibrium and kinetics of membrane-anchored receptors and
  ligands in cell adhesion: insights from computational model systems and
  theory

abstract:
  The adhesion of cell membranes is mediated by the binding of
membrane-anchored receptor and ligand proteins. In this article, we review
recent results from simulations and theory that lead to novel insights on how
the binding equilibrium and kinetics of these proteins is affected by the
membranes and by the membrane anchoring and molecular properties of the
proteins. Simulations and theory both indicate that the binding equilibrium
constant K2D and the on- and off-rate constants of anchored receptors and
ligands in their 'two-dimensional' (2D) membrane environment strongly depend on
the membrane roughness from thermally excited shape fluctuations on nanoscales.
Recent theory corroborated by simulations provides a general relation between
K2D} and the binding constant K3D of soluble variants of the receptors and
ligands that lack the membrane anchors and are free to diffuse in three
dimensions (3D).


title:
Quantitative equidistribution of Galois orbits of small points in the
  N-dimensional torus

abstract:
  We present a quantitative version of Bilu's theorem on the limit distribution
of Galois orbits of sequences of points of small height in the $N$-dimensional
algebraic torus. Our result gives, for a given point, an explicit bound for the
discrepancy between its Galois orbit and the uniform distribution on the
compact subtorus, in terms of the height and the generalized degree of the
point.


title: Neural Word Segmentation Learning for Chinese

abstract:
  Most previous approaches to Chinese word segmentation formalize this problem
as a character-based sequence labeling task where only contextual information
within fixed sized local windows and simple interactions between adjacent tags
can be captured. In this paper, we propose a novel neural framework which
thoroughly eliminates context windows and can utilize complete segmentation
history. Our model employs a gated combination neural network over characters
to produce distributed representations of word candidates, which are then given
to a long short-term memory (LSTM) language scoring model. Experiments on the
benchmark datasets show that without the help of feature engineering as most
existing approaches, our models achieve competitive or better performances with
previous state-of-the-art methods.


title:
An analysis of interplanetary solar radio emissions associated with a
  coronal mass ejection

abstract:
  Coronal mass ejections (CMEs) are large-scale eruptions of magnetized plasma
that may cause severe geomagnetic storms if Earth-directed. Here we report a
rare instance with comprehensive in situ and remote sensing observa- tions of a
CME combining white-light, radio, and plasma measurements from four different
vantage points. For the first time, we have successfully applied a radio
direction-finding technique to an interplanetary type II burst detected by two
identical widely separated radio receivers. The derived locations of the type
II and type III bursts are in general agreement with the white light CME recon-
struction. We find that the radio emission arises from the flanks of the CME,
and are most likely associated with the CME-driven shock. Our work demon-
strates the complementarity between radio triangulation and 3D reconstruction
techniques for space weather applications.


title:
A study on evolution of a cold atom cloud in a time dependent radio
  frequency dressed potential

abstract:
  Using a Direct Simulation Monte Carlo technique, we have studied the time
evolution of a cold atom cloud interacting with a time dependent radio
frequency (rf) dressed state potential. Exposure of a cloud of $^{87}Rb$ atoms,
trapped in a quadrupole magnetic trap, to a time dependent rf-field with
increasing amplitude and decreasing frequency, shows a variation in the number
of trapped atoms and the overall shape of the atom cloud. It is shown by
simulations that, initially at lower rf-field strength, the rf-field results in
ejection of atoms from the trap, leading to evaporative cooling of the atom
cloud. Later, at higher rf-field strength, the atoms undergo the non-adiabatic
Landau-Zener (LZ) transitions, which leads to their trapping in an rf-dressed
state potential of toroidal shape. The results of simulations explain the
experimentally observed results. The simulations can be useful to predict the
atom cloud dynamics and trapping geometries with other forms of the potential.


title: Topological Expansion in the Complex Cubic Log-Gas Model. One-Cut Case

abstract:
  We prove the topological expansion for the cubic log-gas partition function
\[ Z_N(t)= \int_\Gamma\cdots\int_\Gamma\prod_{1\leq j<k\leq N}(z_j-z_k)^2
\prod_{k=1}^Ne^{-N\left(-\frac{z^3}{3}+tz\right)}\mathrm dz_1\cdots \mathrm
dz_N, \] where $t$ is a complex parameter and $\Gamma$ is an unbounded contour
on the complex plane extending from $e^{\pi \mathrm i}\infty$ to $e^{\pi
\mathrm i/3}\infty$. The complex cubic log-gas model exhibits two phase regions
on the complex $t$-plane, with one cut and two cuts, separated by analytic
critical arcs of the two types of phase transition: split of a cut and birth of
a cut. The common point of the critical arcs is a tricritical point of the
Painlev\'e I type. In the present paper we prove the topological expansion for
$\log Z_N(t)$ in the one-cut phase region. The proof is based on the
Riemann--Hilbert approach to semiclassical asymptotic expansions for the
associated orthogonal polynomials and the theory of $S$-curves and quadratic
differentials.


title:
Separability and entanglement of n-qubits and a qubit with a qudit using
  Hilbert-Schmidt decompositions

abstract:
  Hilbert-Schmidt (HS) decompositions are employed for analyzing systems of
n-qubits, and a qubit with a qudit. Negative eigenvalues, obtained by
partial-transpose (PT) plus local unitary transformations (PTU) for one qubit
from the whole system, are used for indicating inseparability. A sufficient
criterion for full separability of the n-qubits and qubit-qudit systems is
given. We use the singular value decomposition (SVD) for improving the
criterion for full separability. General properties of entanglement and
separability are analyzed for a system of a qubit and a qudit and n-qubits
systems, with emphasis on maximally disordered subsystems (MDS) (i.e., density
matrices rho(MDS) for which tracing over any subsystem gives the unit density
matrix). A sufficient condition that rho(MDS) is not separable is that it has
an eigenvalue larger than 1/d for a qubit and a qudit, and larger than
1/2^(n-1) for n-qubits system. The PTU transformation does not change the
eigenvalues of the n-qubits MDS density matrices for odd n. Thus the
Peres-Horodecki criterion does not give any information about entanglement of
these density matrices, but this criterion is useful for indicating
inseparability for even n. The changes of the entanglement and separability
properties of the GHZ state, the Braid entangled state and the W state by
mixing them with white noise are analyzed by the use of the present methods.
The entanglement and separability properties of the GHZ-diagonal density
matrices, composed of mixture of 8 GHZ density matrices with probabilities
p(i), is analyzed as function of these probabilities. In some cases we show
that the Peres-Horodecki criterion is both sufficient and necessary.


title:
Heat transfer and wall temperature effects in shock wave turbulent
  boundary layer interactions

abstract:
  Direct numerical simulations are carried out to investigate the effect of the
wall temperature on the behavior of oblique shock-wave/turbulent boundary layer
interactions at freestream Mach number $2.28$ and shock angle of the wedge
generator $\varphi = 8^{\circ}$. Five values of the
wall-to-recovery-temperature ratio ($T_w/T_r$) are considered, corresponding to
cold, adiabatic and hot wall thermal conditions. We show that the main effect
of cooling is to decrease the characteristic scales of the interaction in terms
of upstream influence and extent of the separation bubble. The opposite
behavior is observed in the case of heating, that produces a marked dilatation
of the interaction region. The distribution of the Stanton number shows that a
strong amplification of the heat transfer occurs across the interaction, and
the maximum values of thermal and dynamic loads are found in the case of cold
wall. The analysis reveals that the fluctuating heat flux exhibits a strong
intermittent behavior, characterized by scattered spots with extremely high
values compared to the mean. Furthermore, the analogy between momentum and heat
transfer, typical of compressible, wall-bounded, equilibrium turbulent flows
does not apply for most part of the interaction domain. The pre-multiplied
spectra of the wall heat flux do not show any evidence of the influence of the
low-frequency shock motion, and the primary mechanism for the generation of
peak heating is found to be linked with the turbulence amplification in the
interaction region.


title: Viral Search algorithm

abstract:
  The article, after a brief introduction on genetic algorithms and their
functioning, presents a kind of genetic algorithm called Viral Search. We
present the key concepts, we formally derive the algorithm and we perform
numerical tests designed to illustrate the potential and limits.


title: Stable laws and Beurling kernels

abstract:
  We identify a close relation between stable distributions and the limiting
homomorphisms central to the theory of regular variation. In so doing some
simplifications are achieved in the direct analysis of these laws in Pitman and
Pitman (2016); stable distributions are themselves linked to homomorphy.


title: Richardson-Lucy Deblurring for Moving Light Field Cameras

abstract:
  We generalize Richardson-Lucy (RL) deblurring to 4-D light fields by
replacing the convolution steps with light field rendering of motion blur. The
method deals correctly with blur caused by 6-degree-of-freedom camera motion in
complex 3-D scenes, without performing depth estimation. We introduce a novel
regularization term that maintains parallax information in the light field
while reducing noise and ringing. We demonstrate the method operating
effectively on rendered scenes and scenes captured using an off-the-shelf light
field camera. An industrial robot arm provides repeatable and known
trajectories, allowing us to establish quantitative performance in complex 3-D
scenes. Qualitative and quantitative results confirm the effectiveness of the
method, including commonly occurring cases for which previously published
methods fail. We include mathematical proof that the algorithm converges to the
maximum-likelihood estimate of the unblurred scene under Poisson noise. We
expect extension to blind methods to be possible following the generalization
of 2-D Richardson-Lucy to blind deconvolution.


title:
Non-homogeneous square functions on general sets: suppression and big
  pieces methods

abstract:
  We aim to showcase the wide applicability and power of the big pieces and
suppression methods in the theory of local $Tb$ theorems. The setting is new:
we consider conical square functions with cones $\{x \in \mathbb{R}^n \setminus
E: |x-y| < 2 \operatorname{dist}(x,E)\}$, $y \in E$, defined on general closed
subsets $E \subset \mathbb{R}^n$ supporting a non-homogeneous measure $\mu$. We
obtain boundedness criteria in this generality in terms of weak type testing of
measures on regular balls $B \subset E$, which are doubling and of small
boundary. Due to the general set $E$ we use metric space methods. Therefore, we
also demonstrate the recent techniques from the metric space point of view, and
show that they yield the most general known local $Tb$ theorems even with
assumptions formulated using balls rather than the abstract dyadic metric
cubes.


title: Topological protection of multiparticle dissipative transport

abstract:
  Topological protection allows robust transport of localized phenomena such as
quantum information, solitons, and dislocations. The transport can be either
dissipative or non-dissipative. Here, we experimentally demonstrate and
theoretically explain the topologically protected dissipative motion of
colloidal particles above a periodic hexagonal magnetic pattern. By driving the
system with periodic modulation loops of an external and spatially homogeneous
magnetic field, we achieve total control over the motion of diamagnetic and
paramagnetic colloids. We can transport simultaneously and independently each
type of colloid along any of the six crystallographic directions of the pattern
via adiabatic or deterministic ratchet motion. Both types of motion are
topologically protected. As an application, we implement an automatic
topologically protected quality control of a chemical reaction between
functionalized colloids. Our results are relevant to other systems with the
same symmetry.


title:
Ergodicity and first passage probability of regime-switching geometric
  Brownian motions

abstract:
  A regime-switching geometric Brownian motion is used to model a geometric
Brownian motion with its coefficients changing randomly according to a Markov
chain. In this work, we give a complete characterization of the recurrent
property of this process. The long time behavior of this process such as its
$p$-th moment is also studied. Moreover, the quantitative properties of the
regime-switching geometric Brownian motion with two-state switching are
investigated to show the difference between geometric Brownian motion with
switching and without switching. At last, some estimates of its first passage
probability are established.


title:
A parametric jet-interpolation theorem for holomorphic automorphisms of
  C^n

abstract:
  We consider the problem of interpolating a holomorphic family of
nondegenerate holomorphic jets on C^n for n > 1, parametrized by points in a
Stein manifold, by a holomorphic family of automorphisms of C^n. We show that
under a suitable topological condition it is possible to find a solution,
thereby generalizing results of Forstneric and Varolin concerning the
nonparametric jet interpolation by automorphisms.


title:
Chiral Ordering Spin Associated Glass like State in SrRuO3SrIrO3
  Superlattice

abstract:
  Heterostructure interface provides a powerful platform to observe rich
emergent phenomena, such as interfacial superconductivity, nontrivial
topological surface state. Here SrRuO3/SrIrO3 superlattices were epitaxially
synthesized. The magnetic and electrical properties of these superlattices were
characterized. Broad cusps in the zero field cooling magnetization curves and
near stable residual magnetization below the broad cusps, as well as two steps
magnetization hysteresis loops are observed. The magnetization relaxes
following a modified Stretched function model indicating coexistence of spin
glass and ferromagnetic ordering in the superlattices. Topological Hall effect
was demonstrated at low temperature and weakened with the increase of SrIrO3
layer thickness. These results suggest that chiral ordering spin texture were
generated at the interfaces due to the interfacial Dzyaloshinskii-Moriya (DM)
interaction, which generates the spin glass behaviors. The present work
demonstrates that SrIrO3 can effectively induce interface DM interactions in
heterostructures, it would pave light on the new research directions of strong
spin orbit interaction oxides, from the viewpoints of both basic science and
prospective spintronics devices applications.


title:
On the properties of Ascent and Descent of Composition operator on
  Orlicz spaces

abstract:
  Here, the composition operators on Orlicz spaces with finite ascent and
descent as well as infinite ascent and descent are characterized.


title: An Ancilla Based Quantum Simulation Framework for Non-Unitary Matrices

abstract:
  The success probability in an ancilla based circuit generally decreases
exponentially in the number of qubits consisted in the ancilla. Although the
probability can be amplified through the amplitude amplification process, the
input dependence of the amplitude amplification makes difficult to sequentially
combine two or more ancilla based circuits. A new version of the amplitude
amplification known as the oblivious amplitude amplification runs independently
of the input to the system register. This allow us to to sequentially combine
two or more ancilla based circuits. However, this type of the amplification
only works when the considered system is unitary or non-unitary but somehow
close to a unitary.
  In this paper, we present a general framework to simulate non-unitary
matrices on ancilla based quantum circuits in which the success probability is
maximized by using the oblivious amplitude amplification. In particular, we
show how to extend a non-unitary matrix to an almost unitary matrix. We then
simulate the extended matrix by using an ancilla based circuit design along
with the oblivious amplitude amplification. Measuring the distance of the
produced matrix to the closest unitary unitary matrix, a lower bound for the
fidelity of the final state obtained from the oblivious amplitude amplification
process is presented. Numerical simulations for random matrices of different
sizes show that independent of the system size, the final amplified
probabilities are generally around 0.75 and the fidelity of the final state is
mostly high and around 0.95. Furthermore, we discuss the complexity analysis
and show that combining two such ancilla based circuits, a matrix product can
be implemented. This may lead us to efficiently implement matrix functions
represented as infinite matrix products on quantum computers.


title:
Time for a change: a tutorial for comparing multiple classifiers through
  Bayesian analysis

abstract:
  The machine learning community adopted the use of null hypothesis
significance testing (NHST) in order to ensure the statistical validity of
results. Many scientific fields however realized the shortcomings of
frequentist reasoning and in the most radical cases even banned its use in
publications. We should do the same: just as we have embraced the Bayesian
paradigm in the development of new machine learning methods, so we should also
use it in the analysis of our own results. We argue for abandonment of NHST by
exposing its fallacies and, more importantly, offer better - more sound and
useful - alternatives for it.


title: Calibration of Phone Likelihoods in Automatic Speech Recognition

abstract:
  In this paper we study the probabilistic properties of the posteriors in a
speech recognition system that uses a deep neural network (DNN) for acoustic
modeling. We do this by reducing Kaldi's DNN shared pdf-id posteriors to phone
likelihoods, and using test set forced alignments to evaluate these using a
calibration sensitive metric. Individual frame posteriors are in principle
well-calibrated, because the DNN is trained using cross entropy as the
objective function, which is a proper scoring rule. When entire phones are
assessed, we observe that it is best to average the log likelihoods over the
duration of the phone. Further scaling of the average log likelihoods by the
logarithm of the duration slightly improves the calibration, and this
improvement is retained when tested on independent test data.


title:
Earliest phases of star formation (EPoS): Dust temperature distributions
  in isolated starless cores

abstract:
  Constraining the temperature and density structure of dense molecular cloud
cores is fundamental for understanding the initial conditions of star
formation. We use Herschel observations of the thermal FIR dust emission from
nearby isolated molecular cloud cores and combine them with ground-based
submillimeter continuum data to derive observational constraints on their
temperature and density structure. The aim of this study is to verify the
validity of a ray-tracing inversion technique developed to derive the dust
temperature and density structure of isolated starless cores directly from the
dust emission maps and to test if the resulting temperature and density
profiles are consistent with physical models. Using this ray-tracing inversion
technique, we derive the dust temperature and density structure of six isolated
starless cloud cores. We employ self-consistent radiative transfer modeling to
the derived density profiles, treating the ISRF as the only heating source. The
best-fit values of local strength of the ISRF and the extinction by the outer
envelope are derived by comparing the self-consistently calculated temperature
profiles with those derived by the ray-tracing method. We find that all
starless cores are significantly colder inside than outside, with the core
temperatures showing a strong negative correlation with peak column density.
This suggests that their thermal structure is dominated by external heating
from the ISRF and shielding by dusty envelopes. The temperature profiles
derived with the ray-tracing inversion method can be well-reproduced with
self-consistent radiative transfer models.


title: Model-based evaluation of scientific impact indicators

abstract:
  Using bibliometric data artificially generated through a model of citation
dynamics calibrated on empirical data, we compare several indicators for the
scientific impact of individual researchers. The use of such a controlled setup
has the advantage of avoiding the biases present in real databases, and allows
us to assess which aspects of the model dynamics and which traits of individual
researchers a particular indicator actually reflects. We find that the simple
citation average performs well in capturing the intrinsic scientific ability of
researchers, whatever the length of their career. On the other hand, when
productivity complements ability in the evaluation process, the notorious $h$
and $g$ indices reveal their potential, yet their normalized variants do not
always yield a fair comparison between researchers at different career stages.
Notably, the use of logarithmic units for citation counts allows us to build
simple indicators with performance equal to that of $h$ and $g$. Our analysis
may provide useful hints for a proper use of bibliometric indicators.
Additionally, our framework can be extended by including other aspects of the
scientific production process and citation dynamics, with the potential to
become a standard tool for the assessment of impact metrics.


title:
Dg analogues of the Zuckerman functors and the dual Zuckerman functors
  II

abstract:
  In the first part of this series of papers we constructed dg analogues of the
Zuckerman functors over commutative rings and the dual Zuckerman functors over
the field of complex numbers. In this paper we construct their derived functors
in view of the theory of model categories.


title:
Ambiguities in gravitational lens models: the density field from the
  source position transformation

abstract:
  Strong gravitational lensing is regarded as the most precise technique to
measure the mass in the inner region of galaxies or galaxy clusters. In
particular, the mass within one Einstein radius can be determined with an
accuracy of order of a few percent or better, depending on the image
configuration. For other radii, however, degeneracies exist between galaxy
density profiles, precluding an accurate determination of the enclosed mass.
The source position transformation (SPT), which includes the well-known
mass-sheet transformation (MST) as a special case, describes this degeneracy of
the lensing observables in a more general way. In this paper we explore
properties of an SPT, removing the MST to leading order, i.e., we consider
degeneracies which have not been described before. The deflection field
$\boldsymbol{\hat{\alpha}}(\boldsymbol{\theta})$ resulting from an SPT is not
curl-free in general, and thus not a deflection that can be obtained from a
lensing mass distribution. Starting from a variational principle, we construct
lensing potentials that give rise to a deflection field
$\boldsymbol{\tilde{\alpha}}$, which differs from $\boldsymbol{\hat{\alpha}}$
by less than an observationally motivated upper limit. The corresponding mass
distributions from these 'valid' SPTs are studied: their radial profiles are
modified relative to the original mass distribution in a significant and
non-trivial way, and originally axi-symmetric mass distributions can obtain a
finite ellipticity. These results indicate a significant effect of the SPT on
quantitative analyses of lens systems. We show that the mass inside the
Einstein radius of the original mass distribution is conserved by the SPT;
hence, as is the case for the MST, the SPT does not affect the mass
determination at the Einstein radius. [...]


title: Modeling and Analysis of SCMA Enhanced D2D and Cellular Hybrid Network

abstract:
  Sparse code multiple access (SCMA) has been recently proposed for the future
wireless networks, which allows non-orthogonal spectrum resource sharing and
enables system overloading. In this paper, we apply SCMA into device-to-device
(D2D) communication and cellular hybrid network, targeting at using the
overload feature of SCMA to support massive device connectivity and expand
network capacity. Particularly, we develop a stochastic geometry based
framework to model and analyze SCMA, considering underlaid and overlaid mode.
Based on the results, we analytically compare SCMA with orthogonal
frequency-division multiple access (OFDMA) using area spectral efficiency (ASE)
and quantify closed-form ASE gain of SCMA over OFDMA. Notably, it is shown that
system ASE can be significantly improved using SCMA and the ASE gain scales
linearly with the SCMA codeword dimension. Besides, we endow D2D users with an
activated probability to balance cross-tier interference in the underlaid mode
and derive the optimal activated probability. Meanwhile, we study resource
allocation in the overlaid mode and obtain the optimal codebook allocation
rule. It is interestingly found that the optimal SCMA codebook allocation rule
is independent of cellular network parameters when cellular users are densely
deployed. The results are helpful in the implementation of SCMA in the hybrid
system.


title: Effect of hydrogen bonding on infrared absorption intensity

abstract:
  We consider how the infrared intensity of an O-H stretch in a hydrogen bonded
complex varies as the strength of the H-bond varies from weak to strong. We
obtain trends for the fundamental and overtone transitions as a function of
donor-acceptor distance R, which is a common measure of H-bond strength. Our
calculations use a simple two-diabatic state model that permits symmetric and
asymmetric bonds, i.e. where the proton affinity of the donor and acceptor are
equal and unequal, respectively. The dipole moment function uses a Mecke form
for the free OH dipole moment, associated with the diabatic states. The
transition dipole moment is calculated using one-dimensional vibrational
eigenstates associated with the H-atom transfer coordinate on the ground state
adiabatic surface of our model. Over 20-fold intensity enhancements for the
fundamental are found for strong H-bonds, where there are significant
non-Condon effects. The isotope effect on the intensity yields a non-monotonic
H/D intensity ratio as a function of R, and is enhanced by the secondary
geometric isotope effect. The first overtone intensity is found to vary
non-monotonically with H-bond strength; strong enhancements are possible for
strong H-bonds. Modifying the dipole moment through the Mecke parameters is
found to have a stronger effect on the overtone than the fundamental. We
compare our findings with those for specific molecular systems analysed through
experiments and theory in earlier works. Our model results compare favourably
for strong and medium strength symmetric H-bonds. However, for weak asymmetric
bonds we find much smaller effects than in earlier work.


title:
Magnetic response of non-interacting and interacting electrons in a
  M\"{o}bius strip

abstract:
  We investigate characteristic features of both non-interacting and
interacting electrons in a M\"{o}bius strip, the simplest possible one-sided
topological system, in presence of an Aharonov-Bohm flux $\phi$. Using
Hartree-Fock mean field theory we determine energy eigenvalues for the
interacting model, while for the non-interacting system an analytical
prescription is given. The interplay between longitudinal and vertical motions
of electrons along with on-site Hubbard interaction yield several anomalous
features of persistent current associated with energy-flux characteristics. The
variation of current with system size and its temperature dependences are also
critically examined. Current is highly sensitive to both these two factors, and
we find that for a particular system size it decreases exponentially with
temperature. Our analysis can be helpful in investigating electronic transport
through any non-trivial topological material.


title:
Well-posedness and global attractors for a non-isothermal viscous
  relaxation of nonlocal Cahn-Hilliard equations

abstract:
  We investigate a non-isothermal viscous relaxation of some nonlocal
Cahn-Hilliard equations. This perturbation problem generates a family of
solution operators, exhibiting dissipation and conservation. The solution
operators admit a family of compact global attractors that are bounded in a
more regular phase-space.


title: Thermodynamic deficiencies of some simple Lindblad operators

abstract:
  Master equations of Lindblad type have attained prominent status in the
fields of quantum optics and quantum information since they are guaranteed to
satisfy fundamental notions of quantum dynamics such as complete positivity.
When Lindblad operators are used to describe thermal reservoirs in contact with
an open quantum system, the fundamental laws of thermodynamics and the
fluctuation-dissipation theorem provide additional mandatory criteria. We show
several examples of innocent-looking Lindblad operators which have questionable
properties in this regard. Compatibility criteria between Hamiltonian and
Lindblad terms as well as consequences of their violation are discussed. An
alternative stochastic approach to dissipative quantum dynamics is outlined and
illustrated through a harmonic-chain model for which the approach of local
Lindblad operators fails.


title: Entropy/IP: Uncovering Structure in IPv6 Addresses

abstract:
  In this paper, we introduce Entropy/IP: a system that discovers Internet
address structure based on analyses of a subset of IPv6 addresses known to be
active, i.e., training data, gleaned by readily available passive and active
means. The system is completely automated and employs a combination of
information-theoretic and machine learning techniques to probabilistically
model IPv6 addresses. We present results showing that our system is effective
in exposing structural characteristics of portions of the IPv6 Internet address
space populated by active client, service, and router addresses.
  In addition to visualizing the address structure for exploration, the system
uses its models to generate candidate target addresses for scanning. For each
of 15 evaluated datasets, we train on 1K addresses and generate 1M candidates
for scanning. We achieve some success in 14 datasets, finding up to 40% of the
generated addresses to be active. In 11 of these datasets, we find active
network identifiers (e.g., /64 prefixes or `subnets') not seen in training.
Thus, we provide the first evidence that it is practical to discover subnets
and hosts by scanning probabilistically selected areas of the IPv6 address
space not known to contain active hosts a priori.


title: Second Order RG Flow in General su(2) Coset Models

abstract:
  We consider a RG flow in a general su(2) coset model perturbed by the least
relevant field. The perturbing field as well as some particular fields of
dimension close to one are constructed recursively in terms of lower level
fields. Using this construction we obtain the structure constants and the
four-point correlation functions in the leading order. This allows us to
compute the mixing coefficients among the fields in the UV and the IR theory.
It turns out that they are in agreement with those found recently using the
domain wall construction up to this order.


title:
Highly ionized disc and transient outflows in the Seyfert galaxy IRAS
  18325-5926

abstract:
  We report on strong X-ray variability and the Fe K band spectrum of the
Seyfert galaxy IRAS 18325-5926 obtained from the 2001 XMM-Newton EPIC pn
observation of a 120 ks duration. While the X-ray source is highly variable,
the 8-10 keV band shows larger variability than that of the lower energies.
Amplified 8-10 keV flux variations are associated with two prominent flares of
the X-ray source during the observation. The Fe K emission is peaked at 6.6 keV
with moderate broadening. It is likely to originate from a highly ionized disc
with the ionization parameter of log xi ~3. The Fe K line flux responds to the
major flare, supporting its disc origin. There is a short burst of the Fe line
flux with no relation to the continuum brightness for which we have no clear
explanation. We also find transient, blueshifted Fe K absorption features,
which can be identified with high-velocity (~0.2 c) outflows of highly ionized
gas, as found in other active galaxies. The deepest absorption feature appears
only briefly (~1 hr) at the onset of the major flare and disappears when the
flare is declining. The rapid evolution of the absorption spectrum makes this
source peculiar among the active galaxies with high velocity outflows. Another
detection of the absorption feature also precedes the other flare. The
variability of the absorption feature partly accounts for the excess
variability in the 8-10 keV band where the absorption feature appears. Although
no reverberation measurement is available, the black hole mass of 2e6 Msun is
inferred from the X-ray variability. When this mass is assumed, the black hole
is accreting at around the Eddington limit, which may fit the highly ionized
disc and strong outflows observed in this galaxy.


title:
Magnitude and timing of the giant planet instability: A reassessment
  from the perspective of the asteroid belt

abstract:
  It is generally accepted today that our solar system has undergone a phase
during which the orbits of the giant planets became very unstable. In recent
years, many studies have identified traces of this event and have provided
reasonable justification for this occurrence. The magnitude (in terms of
orbital variation) and the timing of the instability though (early or late with
respect to the dispersal of the gas disk) still remains an open debate. The
terrestrial planets seem to set a strict constraint: either the giant planet
instability happened early, while the terrestrial planets were still forming,
or the orbits of Jupiter and Saturn had to separate from each other
impulsively, with a large enough `jump' in semimajor axis (Brasser et al. 2009;
Kaib and Chambers 2016) for the terrestrial planets to remain stable. Because a
large orbital jump is a low probability event, the early instability hypothesis
seems to be favored. However, the asteroid belt would also evolve in a
different way, assuming different instability amplitudes. These two constraints
need to match each other in order to favor one scenario over the other.
Considering an initially dynamically cold disk of asteroids, Morbidelli et al.
(2010) concluded that a comparably large jump is needed to reconstruct the
current asteroid belt. Here we confirm the same conclusion, but considering an
asteroid population already strongly excited in eccentricity, such as that
produced in the Grand Tack scenario (Walsh et al. 2011). Because the asteroids
existed since the time of removal of the gas disk, unlike the terrestrial
planets, this constraint on the width of the giant planet jump is valid
regardless of whether the instability happened early or late. Hence, at this
stage, assuming an early instability does not appear to provide any advantage
in terms of the probabilistic reconstruction of the solar system structure.


title: Uniform approximation of non-autonomous evolution equations

abstract:
  We study $L^2$-maximal regularity for non-autonomous evolution equations of
the form \begin{equation}\label{Abstract equation} \dot u(t)+\mathcal
A(t)u(t)=f(t)\ \ t\in[0,T],\ \ u(0)=u_0. \end{equation} where $\mathcal A(t),\
t\in [0,T]$ arise from a non-autonomous sesquilinear forms $a(t,\cdot,\cdot)$
on a Hilbert space $H$ with constant domain $V\subset H.$ $L^2-$maximal
regularity result is proved recently in \cite{Ar-Mo15} when $a$ is H\"older
continuous of type $\alpha>1/2.$ In this paper we recover the same results by
an approximation method developed in \cite{ELLA13}, \cite{LASA14} and
\cite{ELLA15}. The method uses an appropriate approximation $\mathcal
A_\Lambda(\cdot)$ of $\mathcal A(\cdot)$ for which
\begin{equation}\label{Abstract equation approx} \dot u_{\Lambda}(t)+\mathcal
A_{\Lambda}(t)u_{\Lambda}(t)=f(t)\ \ t\in[0,T],\ \ u_{\Lambda}(0)=u_0
\end{equation} has $L^2$-maximal regularity where $\Lambda$ is a subdivision of
$[0,T].$ Moreover, under a little more assumptions on the modulus of continuity
we show that the solutions of (\ref{Abstract equation approx}) converges in
$L^2(0,T,V)\cap H^1(0,T,H)\cap C(0,T,V)$ uniformly on the initial datas
$(u_0,f)$ to the solution of (\ref{Abstract equation}) as $|\Lambda|
\rightarrow 0.$


title:
Lie superbialgebra structures on the Lie superalgebra $({\cal C}^3 +
  {\cal A})$ and deformation of related integrable Hamiltonian systems

abstract:
  Admissible structure constants related to the dual Lie superalgebras of
particular Lie superalgebra $({\cal C}^3 + {\cal A})$ are found by
straightforward calculations from the matrix form of super Jacobi and mixed
super Jacobi identities which are obtained from adjoint representation. Then,
by making use of the automorphism supergroup of the Lie superalgebra $({\cal
C}^3 + {\cal A})$, the Lie superbialgebra structures on the Lie superalgebra
$({\cal C}^3 + {\cal A})$ are obtained and classified into inequivalent 31
families. We also determine all corresponding coboundary and bi-r-matrix Lie
superbialgebras. The quantum deformations associated with some Lie
superbialgebras $({\cal C}^3 + {\cal A})$ are obtained, together with the
corresponding deformed Casimir elements. As an application of these quantum
deformations, we construct a deformed integrable Hamiltonian system from the
representation of the Hopf superalgebra ${{U}_{_\lambda}}^{\hspace{-1mm}({\cal
C}_{p=1}^{2,\epsilon} \oplus {\cal A}_{1,1})}\big(({\cal C}^3+{\cal A})\big)$.


title:
Neither Quick Nor Proper -- Evaluation of QuickProp for Learning Deep
  Neural Networks

abstract:
  Neural networks and especially convolutional neural networks are of great
interest in current computer vision research. However, many techniques,
extensions, and modifications have been published in the past, which are not
yet used by current approaches. In this paper, we study the application of a
method called QuickProp for training of deep neural networks. In particular, we
apply QuickProp during learning and testing of fully convolutional networks for
the task of semantic segmentation. We compare QuickProp empirically with
gradient descent, which is the current standard method. Experiments suggest
that QuickProp can not compete with standard gradient descent techniques for
complex computer vision tasks like semantic segmentation.


title: Problems on One Way Road Networks

abstract:
  Let $OWRN = \left\langle W_x,W_y \right\rangle$ be a One Way Road Network
where $W_x$ and $W_y$ are the sets of directed horizontal and vertical roads
respectively. $OWRN$ can be considered as a variation of directed grid graph.
The intersections of the horizontal and vertical roads are the vertices of
$OWRN$ and any two consecutive vertices on a road are connected by an edge. In
this work, we analyze the problem of collision free traffic configuration in a
$OWRN$. A traffic configuration is a two-tuple $TC=\left\langle OWRN,
C\right\rangle$, where $C$ is a set of cars travelling on a pre-defined path.
We prove that finding a maximum cardinality subset $C_{sub}\subseteq C$ such
that $TC=\left\langle OWRN, C_{sub}\right\rangle$ is collision-free, is
NP-hard. Lastly we investigate the properties of connectedness, shortest paths
in a $OWRN$.


title: LLFR: A Lanczos-Based Latent Factor Recommender for Big Data Scenarios

abstract:
  The purpose if this master's thesis is to study and develop a new algorithmic
framework for Collaborative Filtering to produce recommendations in the top-N
recommendation problem. Thus, we propose Lanczos Latent Factor Recommender
(LLFR); a novel "big data friendly" collaborative filtering algorithm for top-N
recommendation. Using a computationally efficient Lanczos-based procedure, LLFR
builds a low dimensional item similarity model, that can be readily exploited
to produce personalized ranking vectors over the item space. A number of
experiments on real datasets indicate that LLFR outperforms other
state-of-the-art top-N recommendation methods from a computational as well as a
qualitative perspective. Our experimental results also show that its relative
performance gains, compared to competing methods, increase as the data get
sparser, as in the Cold Start Problem. More specifically, this is true both
when the sparsity is generalized - as in the New Community Problem, a very
common problem faced by real recommender systems in their beginning stages,
when there is not sufficient number of ratings for the collaborative filtering
algorithms to uncover similarities between items or users - and in the very
interesting case where the sparsity is localized in a small fraction of the
dataset - as in the New Users Problem, where new users are introduced to the
system, they have not rated many items and thus, the CF algorithm can not make
reliable personalized recommendations yet.


title: On the Resilience of Scalar and Vector Vortex Modes in Turbulence

abstract:
  Free-space optical communication with spatial modes of light has become
topical due to the possibility of dramatically increasing communication
bandwidth via Mode Division Multiplexing (MDM). While both scalar and vector
vortex modes have been used as transmission bases, it has been suggested that
the latter is more robust in turbulence. Using orbital angular momentum as an
example, we demonstrate theoretically and experimentally that the crosstalk due
to turbulence is the same in the scalar and vector basis sets of such modes.
This work brings new insights about the behaviour of vector and scalar modes in
turbulence, but more importantly it demonstrates that when considering optimal
modes for MDM, the choice should not necessarily be based on their vectorial
nature.


title:
Antibunching and Photon Blockade in a coupled Single Quantum Dot-Cavity
  System

abstract:
  In this note we present some results concerning photon blockade and
antibunching in a system consisting of a quantum dot embedded in a microcavity.
We give analytic conditions for resonant and non-resonant photon blockade,
valid for small values of the external pump amplitude. Starting from these
results, we discuss the quantum states characteristics of the system within a
master equation formalism and highlight quantities like stationary second order
correlations both static and dynamic and one-photon purity.


title: Closed sets of Mahler measures

abstract:
  Given a $k$-variable Laurent polynomial $F$, any $l\times k$ integer matrix
$A$ naturally defines an $l$-variable Laurent polynomial $F_A.$ I prove that
for fixed $F$ the set $\mathcal M(F)$ of all the logarithmic Mahler measures
$m(F_A)$ of $F_A$ for all $A$ is a closed subset of the real line. Moreover,
the matrices $A$ can be assumed to be of a special form, which I call Primitive
Hermite Normal Form. Furthermore, if $F$ has integer coefficients and $\mathcal
M(F)$ contains $0,$ then $0$ is an isolated point of this set.
  I also show that, for a given bound $B>0$, the set ${\mathcal M}_B$ of all
Mahler measures of integer polynomials in any number of variables and having
length (sum of the moduli of its coefficients) at most $B$ is closed. Again,
$0$ is an isolated point of ${\mathcal M}_B$.
  These results constitute evidence consistent with a conjecture of Boyd from
1980 to the effect that the union $\mathcal L$ of all sets ${\mathcal M}_B$ for
$B>0$ is closed, with $0$ an isolated point of $\mathcal L$.


title: Switchable Particle Statistics with an Embedding Quantum Simulator

abstract:
  We propose the implementation of a switch of particle statistics with an
embedding quantum simulator. By encoding both Bose-Einstein and Fermi-Dirac
statistics into an enlarged Hilbert space, the statistics of quantum particles
may be changed in situ during the time evolution, from bosons to fermions and
from fermions to bosons, as many times as desired. We illustrate our proposal
with few-qubit examples, although the protocol is straightforwardly extendable
to larger numbers of particles. This proposal can be implemented on different
quantum platforms such as trapped ions, quantum photonics, and superconducting
circuits, among others. The possibility to implement permutation symmetrization
and antisymmetrization of quantum particles enhances the toolbox of quantum
simulations, for unphysical operations as well as for symmetry transformations.


title:
Switching management by adiabatic passage in two periodically modulated
  nonlinear waveguides

abstract:
  We theoretically investigate light propagation in two periodically modulated
nonlinear waveguides with certain propagation constant detuning between two
guides. By slowly varying the amplitude of modulation, we can steer the light
to the desired output waveguide when equal amounts of lights are launched into
each waveguide. We also reveal that the light propagation dynamics depends
sensitively on the detuning between two guides. Our findings can be explained
qualitatively by means of adiabatic navigation of the extended nonlinear
Floquet states.


title: Mutations and Pointing for Brauer Tree Algebras

abstract:
  Brauer tree algebras are important and fundamental blocks in the modular
representation theory of groups. In this research, we present a combination of
two main approaches to the tilting theory of Brauer tree algebras.
  The first approach is the theory initiated by Rickard, providing a direct
link between the ordinary Brauer tree algebra and a particular algebra called
the Brauer star algebra. This approach was continued by Schaps-Zakay with their
theory of pointing the tree.
  The second approach is the theory developed by Aihara, relating to the
sequence of mutations from the ordinary Brauer tree algebra to the star-algebra
of the Brauer tree. Our main purpose in this research is to combine these two
approaches:
  We find an algorithm for which we are able to obtain a tilting complex
constructed from irreducible complexes of length two {[}SZ1{]}, which is
obtained from a sequence of mutations and corresponds to the star-to-tree
complex for the pointing given by a reversed Green's walk. For the algorithm
given by Aihara in \cite{Ai}, we prove that Aihara's tilting complex can be
obtained from the completely folded Rickard tree-to-star complex with left
alternating pointing by a permutation of projectives corresponding to the
cyclic ordering of edges at vertices of non-zero even distance from the
exceptional vertex. The natural numbering of the Aihara algorithm can be
optained from the left alternating pinting by the inverse of this permutation.


title: Delayed Gambler's Ruin

abstract:
  We present here a new extended model of the gambler's ruin problem by
incorporating delays in receiving of rewards and paying of penalties. When
there is a difference between two delays, an exact analysis of the ruin
probability is difficult. We derive an approximate scheme to find an effective
shift in the initial assets of the gambler. Through comparison against computer
simulations, this approximation is shown to work for small differences between
the two delays.


title: Spinning solutions in general relativity with infinite central density

abstract:
  This paper presents general relativistic numerical simulations of uniformly
rotating polytropes. Equations are developed using MSQI coordinates, but taking
a logarithm of the radial coordinate. The result is relatively simple
elliptical differential equations. Due to the logarithmic scale, we can resolve
solutions with near-singular mass distributions near their center, while the
solution domain extends many orders of magnitude larger than the radius of the
distribution (to connect with flat space-time). Rotating solutions are found
with very high central energy densities for a range of adiabatic exponents.
Analytically, assuming the pressure is proportional to the energy density
(which is true for polytropes in the limit of large energy density), we
determine the small radius behavior of the metric potentials and energy
density. This small radius behavior agrees well with the small radius behavior
of large central density numerical results, lending confidence to our numerical
approach. We compare results with rotating solutions available in the
literature, which show good agreement. We study the stability of spherical
solutions: instability sets in at the first maximum in mass versus central
energy density; this is also consistent with results in the literature, and
further lends confidence to the numerical approach.


title:
Estimating direction in brain-behavior interactions: Proactive and
  reactive brain states in driving

abstract:
  Conventional neuroimaging analyses have revealed the computational
specificity of localized brain regions, exploiting the power of the subtraction
technique in fMRI and event-related potential analyses in EEG. Moving beyond
this convention, many researchers have begun exploring network-based
neurodynamics and coordination between brain regions as a function of
behavioral parameters or environmental statistics; however, most approaches
average evoked activity across the experimental session to study task-dependent
networks. Here, we examined on-going oscillatory activity and use a methodology
to estimate directionality in brain-behavior interactions. After source
reconstruction, activity within specific frequency bands in a priori regions of
interest was linked to continuous behavioral measurements, and we used a
predictive filtering scheme to estimate the asymmetry between brain-to-behavior
and behavior-to-brain prediction. We applied this approach to a simulated
driving task and examine directed relationships between brain activity and
continuous driving behavior (steering or heading error). Our results indicated
that two neuro-behavioral states emerge in this naturalistic environment: a
Proactive brain state that actively plans the response to the sensory
information, and a Reactive brain state that processes incoming information and
reacts to environmental statistics.


title: Digits that are not: Generating new types through deep neural nets

abstract:
  For an artificial creative agent, an essential driver of the search for
novelty is a value function which is often provided by the system designer or
users. We argue that an important barrier for progress in creativity research
is the inability of these systems to develop their own notion of value for
novelty. We propose a notion of knowledge-driven creativity that circumvent the
need for an externally imposed value function, allowing the system to explore
based on what it has learned from a set of referential objects. The concept is
illustrated by a specific knowledge model provided by a deep generative
autoencoder. Using the described system, we train a knowledge model on a set of
digit images and we use the same model to build coherent sets of new digits
that do not belong to known digit types.


title:
Reheating and preheating in the simplest extension of Starobinsky
  inflation

abstract:
  The epochs of reheating and preheating are studied in a simple extension of
the Starobinsky inflationary model, which consists of an $R^2$--correction to
the Einstein--Hilbert action and an additional scalar field. We find that if
the $R^2$--correction at the end of inflation is dynamically important, it
affects the expansion rate and as a consequence the reheating and preheating
processes. While we find that the reheating temperature and duration of
reheating are only slightly affected, the effect has to be taken into account
when comparing the theory to data. In the case of preheating, the gravitational
corrections can significantly affect the decay of the second field. Particle
production is strongly affected for certain values of the parameters in the
theory.


title: Jamming anomaly in $\mathcal{PT}$-symmetric systems

abstract:
  The Schr\"odinger equation with a $\mathcal{PT}$-symmetric potential is used
to model an optical structure consisting of an element with gain coupled to an
element with loss. At low gain-loss amplitudes $\gamma$, raising the amplitude
results in the energy flux from the active to the leaky element being boosted.
We study the anomalous behaviour occurring for larger $\gamma$, where the
increase of the amplitude produces a drop of the flux across the gain-loss
interface. We show that this jamming anomaly is either a precursor of the
exceptional point, where two real eigenvalues coalesce and acquire imaginary
parts, or precedes the eigenvalue's immersion in the continuous spectrum.


title: Quantum leaps of black holes: Magnifying glasses of quantum gravity

abstract:
  We show using simple arguments, that the conceptual triad of a {\it
classical} black hole, semi-classical Hawking emission and geometry
quantization is inherently, mutually incompatible. Presence of any two
explicitly violates the third. We argue that geometry quantization, if realized
in nature, magnifies the quantum gravity features hugely to catapult them into
the realm of observational possibilities. We also explore a quantum route
towards extremality of the black holes.


title:
Dynamical analysis of $R\dfrac{1}{\Box^{2}}R$ cosmology: Impact of
  initial conditions and constraints from supernovae

abstract:
  We discuss the cosmological implications of the $R~\Box^{-2}R$ nonlocal
modification to standard gravity. We relax the assumption of special initial
conditions in the local formulation of the theory, perform a full phase-space
analysis of the system, and show that the late-time cosmology of the model
exhibits two distinct evolution paths, on which a large range of values for the
present equation of state can be reached. We then compare the general solutions
to supernovae data and place constraints on the parameters of the model. In
particular, we find that the mass parameter of the theory should be smaller
than 1.2 in Hubble units.


title: Stochastic integrals and BDG's inequalities in Orlicz-type spaces

abstract:
  In this paper we extend an inequality of Lenglart, L\'epingle and Pratelli
\cite[Lemma 1.1]{LLP} to general continuous adapted stochastic processes with
values in topology spaces. By this inequality we show Burkholder-Davies-Gundy's
inequality for stochastic integrals in Orlicz-type spaces (a class of
quasi-Banach spaces) with respect to cylindrical Brownian motions.


title: TwiSE at SemEval-2016 Task 4: Twitter Sentiment Classification

abstract:
  This paper describes the participation of the team "TwiSE" in the SemEval
2016 challenge. Specifically, we participated in Task 4, namely "Sentiment
Analysis in Twitter" for which we implemented sentiment classification systems
for subtasks A, B, C and D. Our approach consists of two steps. In the first
step, we generate and validate diverse feature sets for twitter sentiment
evaluation, inspired by the work of participants of previous editions of such
challenges. In the second step, we focus on the optimization of the evaluation
measures of the different subtasks. To this end, we examine different learning
strategies by validating them on the data provided by the task organisers. For
our final submissions we used an ensemble learning approach (stacked
generalization) for Subtask A and single linear models for the rest of the
subtasks. In the official leaderboard we were ranked 9/35, 8/19, 1/11 and 2/14
for subtasks A, B, C and D respectively.\footnote{We make the code available
for research purposes at
\url{https://github.com/balikasg/SemEval2016-Twitter\_Sentiment\_Evaluation}.}


title: New Superpotential in Conservation Laws in General Relativity

abstract:
  This work refers to the new formula for the superpotential Uikl in
conservation laws in general relativity satisfying the integral and
differential conservation laws within the Schwarzschild metric. The new
superpotential is composed of two terms. The first term is based on Mollers
concept and its a function of the metric gik and its first derivative only. The
second term is the antisymmetric tensor density of weight plus one and it
consists of higher derivatives of the metric gik. Although the new
superpotential consists of higher derivatives of the metric gik it might bring
a new evaluation of the conservative quantities in general relativity


title: Revisiting Conserved Charges in Higher Curvature Gravitational Theories

abstract:
  Restricting the covariant gravitational phase spaces to the manifold of
parametrized families of solutions, the mass, angular momenta, entropies, and
electric charges can be calculated by a single and simple method. In this
method, which has been called "solution phase space method," conserved charges
are unambiguous and regular. Moreover, assuming the generators of the charges
to be exact symmetries, entropies and other conserved charges can be calculated
on almost arbitrary surfaces, not necessarily horizons or asymptotics. Hence,
the first law of thermodynamics would be a local identity relating the exact
symmetries to which the mass, angular momentum, electric charge, and entropy
are attributed. In this paper, we apply this powerful method to the $f(R)$
gravitational theories accompanied by the terms quadratic in the Riemann and
Ricci tensors. Furthermore, conserved charges and the first law of
thermodynamics for some of their black hole solutions are exemplified. The
examples include warped AdS$_3$, charged static BTZ, and 3-dimensional $z=3$
Lifshitz black holes.


title:
From Conformational Spread to Allosteric and Cooperative models of E.
  coli flagellar motor

abstract:
  Escherichia coli swims using flagella activated by rotary motors. The
direction of rotation of the motors is indirectly regulated by the binding of a
single messenger protein. The conformational spread model has been shown to
accurately describe the equilibrium properties as well as the dynamics of the
flagellar motor. In this paper we study this model from an analytic point of
view. By exploiting the separation of timescales observed in experiments, we
show how to reduce the conformational spread model to a coarse-grained,
cooperative binding model. We show that this simplified model reproduces very
well the dynamics of the motor switch.


title: Closed-form evaluation of 2D static lattice sums

abstract:
  In the present paper, employing properties of the complete elliptic integrals
of the first and second kind, we deduce closed-form formulae for the lattice
sums and other new formulae. Applications to the effective properties of
regular and random composites are discussed. We also discuss the Eisenstein
summation method and the Rayleigh method used in computations.


title:
Stability and instability of Ellis and phantom wormholes: Are there
  ghosts?

abstract:
  It is concluded in the literature that Ellis wormhole is unstable under small
perturbations and would decay either to the Schwarzschild black hole or expand
away to infinity. While this deterministic conclusion of instability is
correct, we show that the Ellis wormhole reduces to Schwarzschild black hole
\textit{only} when the Ellis solution parameter $\gamma $ assumes a complex
value $-i$. We shall then reexamine stability of Ellis and phantom wormholes
from the viewpoint of local and asymptotic observers by using a completely
different approach, viz., we adapt Tangherlini's nondeterministic, prequantal
statistical simulation about photon motion in the real optical medium to an
effective medium reformulation of motions obtained via Hamilton's
optical-mechanical analogy in a gravity field. A crucial component of
Tangherlini's idea is the observed increase of momentum of the photons entering
a real medium. We show that this fact has a heuristic parallel in the effective
medium\ version of the Pound-Rebka experiment in gravity. Our conclusion is
that there is a non-zero probability that Ellis and phantom wormholes could
appear stable or unstable depending on the location of observers and on the
values of $\gamma$, leading to the possibility of \textit{ghost wormholes}
(like ghost stars). The Schwarzschild horizon, however, would always appear
certainly stable ($R=1$, $T=0$) to observers regardless of their location.
Phantom wormholes of bounded mass in the extreme limit $a\rightarrow -1$ are
also shown to be stable just as the Schwarzschild black hole is. We shall
propose a thought experiment showing that our non-deterministic results could
be numerically translated into observable deterministic signatures of ghost
wormholes.


title:
Minimal $P$-symmetric periodic solutions of nonlinear Hamiltonian
  systems

abstract:
  In this paper some existence results for the minimal P-symmetric periodic
solutions are proved for first order autonomous Hamiltonian systems when the
Hamiltonian function is superquadratic, asymptotically linear and subquadratic.
These are done by using critical points theory, Galerkin approximation
procedure, Maslov $P$-index theory and its iteration inequalities.


title: Note on the Schwarzschild-phantom wormhole

abstract:
  Recently, it has been shown by Lobo, Parsaei and Riazi (LPR) that phantom
energy with $\omega =p_{r}/\rho <-1$ could support phantom wormholes. Several
classes of such solutions have been derived by them. While the inner spacetime
is represented by asymptotically flat phantom wormhole that have repulsive
gravity, it is most likely to be unstable to perturbations. Hence, we consider
a situation, where a phantom wormhole is somehow trapped inside a Schwarzschild
sphere across a thin shell. Applying the method developed by Garcia, Lobo and
Visser (GLV), we shall exemplify that the shell can possess zones of stability
depending on certain constraints. It turns out that zones corresponding to
"force" constraint are more restrictive than those from the "mass" constraint.
We shall also enumerate the interior energy content by using the gravitational
energy integral proposed by Lynden-Bell, Katz and Bi% \v{c}\'ak. It turns out
that, even though the interior mass is positive, the integral implies repulsive
energy. This is consistent with the phantom nature of interior matter.


title: New observational constraints on f(T) gravity from cosmic chronometers

abstract:
  We use the local value of the Hubble constant recently measured with 2.4%
precision, as well as the latest compilation of cosmic chronometers data,
together with standard probes such as Supernovae Type Ia and Baryon Acoustic
Oscillation distance measurements, in order to impose constraints on the viable
and most used f(T) gravity models, where T is the torsion scalar in
teleparallel gravity. In particular, we consider three f(T) models with two
parameters, out of which one is independent, and we quantify their deviation
from $\Lambda$CDM cosmology through a sole parameter. Our analysis reveals that
for one of the models a small but non-zero deviation from $\Lambda$CDM
cosmology is slightly favored, while for the other models the best fit is very
close to $\Lambda$CDM scenario. Clearly, f(T) gravity is consistent with
observations, and it can serve as a candidate for modified gravity.


title: Stochastic Hamiltonian flows with singular coefficients

abstract:
  In this paper we study the following stochastic Hamiltonian system in
${\mathbb R}^{2d}$ (a second order stochastic differential equation), $$ d \dot
X_t=b(X_t,\dot X_t)d t+\sigma(X_t,\dot X_t)d W_t,\ \ (X_0,\dot
X_0)=(x,v)\in{\mathbb R}^{2d}, $$ where $b(x,v):{\mathbb R}^{2d}\to{\mathbb
R}^d$ and $\sigma(x,v):{\mathbb R}^{2d}\to{\mathbb R}^d\otimes{\mathbb R}^d$
are two Borel measurable functions. We show that if $\sigma$ is bounded and
uniformly non-degenerate, and $b\in H^{2/3,0}_p$ and $\nabla\sigma\in L^p$ for
some $p>2(2d+1)$, where $H^{\alpha,\beta}_p$ is the Bessel potential space with
differentiability indices $\alpha$ in $x$ and $\beta$ in $v$, then the above
stochastic equation admits a unique strong solution so that $(x,v)\mapsto
Z_t(x,v):=(X_t,\dot X_t)(x,v)$ forms a stochastic homeomorphism flow, and
$(x,v)\mapsto Z_t(x,v)$ is weakly differentiable with
ess.$\sup_{x,v}E\left(\sup_{t\in[0,T]}|\nabla Z_t(x,v)|^q\right)<\infty$ for
all $q\geq 1$ and $T\geq 0$. Moreover, we also show the uniqueness of
probability measure-valued solutions for kinetic Fokker-Planck equations with
rough coefficients by showing the well-posedness of the associated martingale
problem and using the superposition principle established by Figalli \cite{Fi}
and Trevisan \cite{Tre}.


title: Cosmology with vector distortion

abstract:
  We consider an extension of Weyl geometry with the most general connection
linearly determined by a vector field. We discuss some of the geometrical
properties within this framework and then we construct gravitational theories
leading to an interesting class of vector-tensor theories with cosmological
applications.


title:
Parameterized post Newtonian approximation in a teleparallel model of
  dark energy with a boundary term

abstract:
  We study the parameterized post-Newtonian approximation in teleparallel model
of gravity with a scalar field. The scalar field is non-minimally coupled to
the scalar torsion as well as to the boundary term introduced in [1]. We show
that, in contrast to the case where the scalar field is only coupled to the
scalar torsion, the presence of the new coupling affects the parameterized
post-Newtonian parameters. These parameters for different situations are
obtained and discussed.


title:
Optimal noise in the hodgepodge machine simulation of the
  Belousov-Zhabotinsky reaction

abstract:
  One of the simplest multilevel cellular automata - the hodgepodge machine -
was modified to best match the chemical trajectory observed in the
Belousov-Zhabotinsky reaction. Noise introduces watersheding of the central
regular pattern into the circular target pattern. This article analyzes
influences of the neighborhood and internal excitation kinds of noise. We have
found that configurations of ignition points, which give circular waves -
target patterns, occur only in the interval of the neighborhood excitation
noise from 30% to 34% and at the internal excitation noise of 12%. Noisy
hodgepodge machine with these parameters is the best approximation to the
experimental Belousov-Zhabotinsky reaction.


title:
Effects of backreaction and exponential nonlinear electrodynamics on the
  holographic superconductors

abstract:
  We analytically study the properties of a $(2+1)$-dimensional $s$-wave
holographic superconductor in the presence of exponential nonlinear
electrodynamics. We consider the case in which the scalar and gauge fields back
react on the background metric. Employing the analytical Sturm-Liouville
method, we find that in the black hole background, the nonlinear
electrodynamics correction will affect the properties of the holographic
superconductors. We find that with increasing both backreaction and nonlinear
parameters, the scalar hair condensation on the boundary will develop more
difficult. We obtain the relation connecting the critical temperature with the
charge density. Our analytical results support that, even in the presence of
the nonlinear electrodynamics and backreaction, the phase transition for the
holographic superconductor still belongs to the second order and the critical
exponent of the system always takes the mean-field value $1/2$.


title:
Dual morse index estimates and application to Hamiltonian systems with
  P-boundary conditions

abstract:
  In this paper, we study the multiplicity of Hamiltonian systems with
P-boundary conditions.


title: Recursive nonlinear-system identification using latent variables

abstract:
  In this paper we develop a method for learning nonlinear systems with
multiple outputs and inputs. We begin by modelling the errors of a nominal
predictor of the system using a latent variable framework. Then using the
maximum likelihood principle we derive a criterion for learning the model. The
resulting optimization problem is tackled using a majorization-minimization
approach. Finally, we develop a convex majorization technique and show that it
enables a recursive identification method. The method learns parsimonious
predictive models and is tested on both synthetic and real nonlinear systems.


title: Pulsations powered by hydrogen shell burning in white dwarfs

abstract:
  In the absence of a third dredge-up episode during the asymptotic giant
branch phase, white dwarf models evolved from low-metallicity progenitors have
a thick hydrogen envelope, which makes hydrogen shell burning be the most
important energy source. We investigate the pulsational stability of white
dwarf models with thick envelopes to see whether nonradial $g$-mode pulsations
are triggered by hydrogen burning, with the aim of placing constraints on
hydrogen shell burning in cool white dwarfs and on a third dredge-up during the
asymptotic giant branch evolution of their progenitor stars. We construct
white-dwarf sequences from low-metallicity progenitors by means of full
evolutionary calculations, and analyze their pulsation stability for the models
in the range of effective temperatures $T_{\rm eff} \sim 15\,000\,-\, 8\,000$
K. We demonstrate that, for white dwarf models with masses $M_{\star} \lesssim
0.71\,\rm M_{\sun}$ and effective temperatures $8\,500 \lesssim T_{\rm eff}
\lesssim 11\,600$ K that evolved from low-metallicity progenitors ($Z= 0.0001$,
$0.0005$, and $0.001$) the dipole ($\ell= 1$) and quadrupole ($\ell=2$) $g_1$
modes are excited mostly due to the hydrogen-burning shell through the
$\varepsilon$-mechanism, in addition to other $g$ modes driven by either the
$\kappa-\gamma$ or the convective driving mechanism. However, the $\varepsilon$
mechanism is insufficient to drive these modes in white dwarfs evolved from
solar-metallicity progenitors. We suggest that efforts should be made to
observe the dipole $g_1$ mode in white dwarfs associated with low-metallicity
environments, such as globular clusters and/or the galactic halo, to place
constraints on hydrogen shell burning in cool white dwarfs and the third
dredge-up episode during the preceding asymptotic giant branch phase.


title: Severi-Brauer varieties; a geometric treatment

abstract:
  These notes present a geometric treatment of Severi-Brauer varieties, without
using any results from the theory of central simple algebras or from Galois
cohomology.


title: Discorrelated quantum states

abstract:
  The statistical properties of photons are fundamental to investigating
quantum mechanical phenomena using light. In multi-photon, two-mode systems,
correlations may exist between outcomes of measurements made on each mode which
exhibit useful properties. Correlation in this sense can be thought of as
increasing the probability of a particular outcome of a measurement on one
subsystem given a measurement on a correlated subsystem. Here, we show a
statistical property we call "discorrelation," in which the probability of a
particular outcome of one subsystem is reduced to zero, given a measurement on
a discorrelated subsystem. We show how such a state can be constructed using
readily available building blocks of quantum optics, namely coherent states,
single photons, beam splitters and projective measurement. We present a variety
of discorrelated states, show that they are entangled, and study their
sensitivity to loss.


title: Stable polarized del Pezzo surfaces

abstract:
  We give a simple sufficient condition for K-stability of polarized del Pezzo
surfaces and for the existence of a constant scalar curvature Kahler metric in
the Kahler class corresponding to the polarization.


title: Minimax is the best electoral system after all

abstract:
  When each voter rates or ranks several candidates for a single office, a
strong Condorcet winner (SCW) is one who beats all others in two-way races.
Among 21 electoral systems examined, 18 will sometimes make candidate X the
winner even if thousands of voters would need to change their votes to make X a
SCW while another candidate Y could become a SCW with only one such change.
Analysis supports the intuitive conclusion that these 18 systems are
unacceptable.
  The well-known minimax system survives this test. It fails 10 others, but
there are good reasons to ignore all 10. Minimax-T adds a new tie-breaker. It
surpasses competing systems on a combination of simplicity, transparency, voter
privacy, input flexibility, resistance to strategic voting, and rarity of ties.
It allows write-ins, machine counting except for write-ins, voters who don't
rate or rank every candidate, and tied ratings or ranks.
  Eleven computer simulation studies used 6 different definitions (one at a
time) of the best candidate, and found that minimax-T always soundly beat all
other tested systems at picking that candidate. A new maximum-likelihood
electoral system named CMO is the theoretically optimum system under reasonable
conditions, but is too complex for use in real-world elections. In computer
simulations, minimax and minimax-T nearly always pick the same winners as CMO.


title: Burkhardt quartic, Barth sextic, and the icosahedron

abstract:
  We study two rational Fano threefolds with an action of the icosahedral group
$\mathfrak{A}_5$. The first one is the famous Burkhardt quartic threefold, and
the second one is the double cover of the projective space branched in the
Barth sextic surface. We prove that both of them are $\mathfrak{A}_5$-Fano
varieties that are $\mathfrak{A}_5$-birationally superrigid. This gives two new
embeddings of the group $\mathfrak{A}_5$ into the space Cremona group.


title:
Hot molecular hydrogen in the central parsec of the Galaxy through
  near-infrared 3D fitting

abstract:
  Aims. We have investigated neutral gas in the central cavity of the
circumnuclear disk (CND) at the Galactic Center, where the ionized minispiral
lies, to describe the H2 distribution and properties in this ionized
environment. Methods. This study was carried out through a spectro-imaging data
cube of the central cavity obtained with SPIFFI on the VLT. The observed field
of view is 36"x 29" , with a spectral resolution R = 1 300 in the
near-infrared. These observations cover several H2 lines. To preserve the
spatial resolution and avoid edge effects, we applied a new line-fitting method
that consists of a regularized 3D fitting. We also applied a more classical 1D
fitting to compare the relative strength of the H2 lines. Results. We present
high spatial and spectral resolution maps of the intensity, velocity, and width
of five H2 lines and an extinction map derived from H2. Molecular gas is
detected everywhere in the field. In particular, in addition to the known CND
features, we detected an emission from the northern arm cloud and from the
minicavity. The excitation diagrams allow us to estimate the temperature, mass,
and density of these features. Conclusions. We interpret the CND emission as
coming from a hot, thermalized, thin layer at the surface of the clouds. The
observed H2 corresponds only to a small fraction of the total H2 mass. The
emission remains fairly strong in the whole central cavity, but it is not
thermalized. A strong deviation from thermal equilibrium is detected near the
minicavity. We suggest that this emission is caused by constantly forming H2
that is destroyed again before it reaches ortho/para equilibrium.


title: An application of the symplectic argument to some Fermat-type Equations

abstract:
  Let $p$ be a prime number. In the early 2000s, it was proved that the Fermat
equations with coefficients \[3x^p + 8y^p + 21z^p =0\quad \text{ and } \quad
3x^p + 4y^p + 5z^p=0 \] do not admit non-trivial solutions for a set of
exponents $p$ with Dirichlet density ${1/4}$ and ${1/8}$, respectively. In this
note, using a recent criterion to decide if two elliptic curves over
$\mathbb{Q}$ with certain types of additive reduction at 2 have symplectically
isomorphic $p$-torsion modules, we improve these densities to ${3/8}$.