title: Fluid Stretching as a Levy Process

abstract:
  We study the relation between flow structure and fluid deformation in steady
two-dimensional random flows. Beyond the linear (shear flow) and exponential
(chaotic flow) elongation paradigms, we find a broad spectrum of stretching
behaviors, ranging from sub- to superlinear, which are dominated by
intermittent shear events. We analyze these behaviors from first principles,
which uncovers stretching as a result of the non-linear coupling between
Lagrangian shear deformation and velocity fluctuations along streamlines. We
derive explicit expressions for Lagrangian deformation and demonstrate that
stretching obeys a coupled continous time random walk, which for broad
distributions of flow velocities describes a L\'evy walk for elongation. The
derived model provides a direct link between the flow and deformation
statistics, and a natural way to quantify the impact of intermittent shear
events on the stretching behavior, which can have strong anomalous diffusive
character.


title: Weak Classicality in Coupled N-Level Quantum Systems

abstract:
  The notion of `weak classical limit' for coupled N-level quantum systems as N
-> infinity is introduced to understand the precise sense in which one attains
classicality. There exist proofs that a system becomes classical at large N. On
the other hand, it is known that non-locality and entanglement, the two
hallmarks of non-classicality, thrive even as N -> infinity. We reconcile these
results in this paper by showing that so called classicality is not so much an
inherent property of the system, as it is a consequence of limited experimental
resources. Our focus is largely on non-locality, for which we study the
Bell-CHSH and CGLMP inequalities for N-level systems.


title:
Segmentation Rectification for Video Cutout via One-Class Structured
  Learning

abstract:
  Recent works on interactive video object cutout mainly focus on designing
dynamic foreground-background (FB) classifiers for segmentation propagation.
However, the research on optimally removing errors from the FB classification
is sparse, and the errors often accumulate rapidly, causing significant errors
in the propagated frames. In this work, we take the initial steps to addressing
this problem, and we call this new task \emph{segmentation rectification}. Our
key observation is that the possibly asymmetrically distributed false positive
and false negative errors were handled equally in the conventional methods. We,
alternatively, propose to optimally remove these two types of errors. To this
effect, we propose a novel bilayer Markov Random Field (MRF) model for this new
task. We also adopt the well-established structured learning framework to learn
the optimal model from data. Additionally, we propose a novel one-class
structured SVM (OSSVM) which greatly speeds up the structured learning process.
Our method naturally extends to RGB-D videos as well. Comprehensive experiments
on both RGB and RGB-D data demonstrate that our simple and effective method
significantly outperforms the segmentation propagation methods adopted in the
state-of-the-art video cutout systems, and the results also suggest the
potential usefulness of our method in image cutout system.


title: Construction of Modular Functors from Modular Tensor Categories

abstract:
  In this paper we follow the constructions of Turaev's book [Tu] closely, but
with small modifications, to construct of a modular functor, in the sense of
Kevin Walker, from any modular tensor category. We further show that this
modular functor has duality and if the modular tensor category category is
Hermitian or unitary, then the resulting modular functor is also Hermitian or
unitary respectively.


title: Floer Field Philosophy

abstract:
  Floer field theory is a construction principle for e.g. 3-manifold invariants
via decomposition in a bordism category and a functor to the symplectic
category, and is conjectured to have natural 4-dimensional extensions. This
survey provides an introduction to the categorical language for the
construction and extension principles and provides the basic intuition for two
gauge theoretic examples which conceptually frame Atiyah-Floer type conjectures
in Donaldson theory as well as the relations of Heegaard Floer homology to
Seiberg-Witten theory.


title: Two-log-convexity of the Catalan-Larcombe-French sequence

abstract:
  The Catalan-Larcombe-French sequence $\{P_n\}_{n\geq 0}$ arises in a series
expansion of the complete elliptic integral of the first kind. It has been
proved that the sequence is log-balanced. In the paper, by exploring a
criterion due to Chen and Xia for testing 2-log-convexity of a sequence
satisfying three-term recurrence relation, we prove that the new sequence
$\{P^2_n-P_{n-1}P_{n+1}\}_{n\geq 1}$ are strictly log-convex and hence the
Catalan-Larcombe-French sequence is strictly 2-log-convex.


title: Bayesian generalized fused lasso modeling via NEG distribution

abstract:
  The fused lasso penalizes a loss function by the $L_1$ norm for both the
regression coefficients and their successive differences to encourage sparsity
of both. In this paper, we propose a Bayesian generalized fused lasso modeling
based on a normal-exponential-gamma (NEG) prior distribution. The NEG prior is
assumed into the difference of successive regression coefficients. The proposed
method enables us to construct a more versatile sparse model than the ordinary
fused lasso by using a flexible regularization term. We also propose a sparse
fused algorithm to produce exact sparse solutions. Simulation studies and real
data analyses show that the proposed method has superior performance to the
ordinary fused lasso.


title: Legendre transformations and Clairaut-type equations

abstract:
  It is noted that the Legendre transformations in the standard formulation of
quantum field theory have the form of functional Clairaut-type equations. It is
shown that in presence of composite fields the Clairaut-type form holds after
loop corrections are taken into account. A new solution to the functional
Clairaut-type equation appearing in field theories with composite fields is
found.


title:
Uniform {\varepsilon}-Stability of Distributed Nonlinear Filtering over
  DNAs: Gaussian-Finite HMMs

abstract:
  In this work, we study stability of distributed filtering of Markov chains
with finite state space, partially observed in conditionally Gaussian noise. We
consider a nonlinear filtering scheme over a Distributed Network of Agents
(DNA), which relies on the distributed evaluation of the likelihood part of the
centralized nonlinear filter and is based on a particular specialization of the
Alternating Direction Method of Multipliers (ADMM) for fast average consensus.
Assuming the same number of consensus steps between any two consecutive noisy
measurements for each sensor in the network, we fully characterize a minimal
number of such steps, such that the distributed filter remains uniformly stable
with a prescribed accuracy level, {\varepsilon} \in (0,1], within a finite
operational horizon, T, and across all sensors. Stability is in the sense of
the \ell_1-norm between the centralized and distributed versions of the
posterior at each sensor, and at each time within T. Roughly speaking, our main
result shows that uniform {\varepsilon}-stability of the distributed filtering
process depends only loglinearly on T and (roughly) the size of the network,
and only logarithmically on 1/{\varepsilon}. If this total loglinear bound is
fulfilled, any additional consensus iterations will incur a fully quantified
further exponential decay in the consensus error. Our bounds are universal, in
the sense that they are independent of the particular structure of the Gaussian
Hidden Markov Model (HMM) under consideration.


title:
Base sizes of imprimitive linear groups and orbits of general linear
  groups on spanning tuples

abstract:
  For a subgroup $L$ of the symmetric group $S_\ell$, we determine the minimal
base size of $GL_d(q)\wr L$ acting on $V_d(q)^\ell$ as an imprimitive linear
group. This is achieved by computing the number of orbits of $GL_d(q)$ on
spanning $m$-tuples, which turns out to be the number of $d$-dimensional
subspaces of $V_m(q)$. We then use these results to prove that for certain
families of subgroups $L$, the affine groups whose stabilisers are large
subgroups of $GL_d(q)\wr L$ satisfy a conjecture of Pyber concerning bases.


title:
Linkage-length dependent structuring behaviour of bent-core molecules in
  helical nanostructures

abstract:
  We studied the correlation between the molecular structure and the formation
of helical nanofilaments (HNFs) of bent-core dimeric molecules with varying
linkage lengths. To obtain precise structural data, a single domain of HNFs was
prepared under physical confinement using porous 1D nanochannels, made up of
anodic aluminium oxide films. Electron microscopy and grazing incidence X-ray
diffraction were used to elucidate the linkage length-dependent formation of
HNFs.


title: Gradient Descent Converges to Minimizers

abstract:
  We show that gradient descent converges to a local minimizer, almost surely
with random initialization. This is proved by applying the Stable Manifold
Theorem from dynamical systems theory.


title: A linking invariant for algebraic curves

abstract:
  We construct a topological invariant of algebraic plane curves, which is in
some sense an adaptation of the linking number of knot theory. This invariant
is shown to be a generalization of the I-invariant of line arrangements
developed by the first author with Artal and Florens. We give two practical
tools for computing this invariant, using a modification of the usual braid
monodromy or using the connected numbers introduced by Shirane. As an
application, we show that this invariant distinguishes several Zariski pairs,
i.e. pairs of curves having same combinatorics, yet different topologies. The
former is the well known Zariski pair found by Artal, composed of a smooth
cubic with 3 tangent lines at its inflexion points. The latter is formed by a
smooth quartic and 3 bitangents.


title: Voltage Scaling of Graphene Device on SrTiO3 Epitaxial Thin Film

abstract:
  Electrical transport in monolayer graphene on SrTiO3 (STO) thin film is
examined in order to promote gate-voltage scaling using a high-k dielectric
material. The atomically flat surface of thin STO layer epitaxially grown on
Nb-doped STO single-crystal substrate offers good adhesion between the high-k
film and graphene, resulting in nonhysteretic conductance as a function of gate
voltage at all temperatures down to 2 K. The two-terminal conductance
quantization under magnetic fields corresponding to quantum Hall states
survives up to 200 K at a magnetic field of 14 T. In addition, the substantial
shift of charge neutrality point in graphene seems to correlate with the
temperature-dependent dielectric constant of the STO thin film, and its
effective dielectric properties could be deduced from the universality of
quantum phenomena in graphene. Our experimental data prove that the operating
voltage reduction can be successfully realized due to the underlying high-k STO
thin film, without any noticeable degradation of graphene device performance.


title: Multi-Sensor Surface Analysis for Robotic Ironing

abstract:
  Robotic manipulation of deformable objects remains a challenging task. One
such task is to iron a piece of cloth autonomously. Given a roughly flattened
cloth, the goal is to have an ironing plan that can iteratively apply a regular
iron to remove all the major wrinkles by a robot. We present a novel solution
to analyze the cloth surface by fusing two surface scan techniques: a curvature
scan and a discontinuity scan. The curvature scan can estimate the height
deviation of the cloth surface, while the discontinuity scan can effectively
detect sharp surface features, such as wrinkles. We use this information to
detect the regions that need to be pulled and extended before ironing, and the
other regions where we want to detect wrinkles and apply ironing to remove the
wrinkles. We demonstrate that our hybrid scan technique is able to capture and
classify wrinkles over the surface robustly. Given detected wrinkles, we enable
a robot to iron them using shape features. Experimental results show that using
our wrinkle analysis algorithm, our robot is able to iron the cloth surface and
effectively remove the wrinkles.


title: Dimension Quotients of Metabelian Lie Rings

abstract:
  For a Lie ring $L$ over the ring of integers, we compare its lower central
series $\{\gamma_n(L)\}_{n\geq 1}$ and its dimension series
$\{\delta_n(L)\}_{n\geq 1}$ defined by setting $\delta_n(L)= L\cap
\varpi^n(L)$, where $\varpi(L)$ is the augmentation ideal of the universal
enveloping algebra of $L$. While $\gamma_n(L)\subseteq\delta_n(L)$ for all
$n\geq 1$, the two series can differ. In this paper it is proved that if $L$ is
a metabelian Lie ring, then $2\delta_n(L)\subseteq\gamma_n(L)$, and
$[\delta_n(L),\,L]=\gamma_{n+1}(L)$, for all $n\geq 1$.


title: Computing the Canonical Height of a Point in Projective Space

abstract:
  We give an algorithm which requires no integer factorization for computing
the canonical height of a point in $\mathbb{P}^1(\mathbb{Q})$ relative to a
morphism $\phi: \mathbb{P}_{\mathbb{Q}}^1 \rightarrow
\mathbb{P}_{\mathbb{Q}}^1$ of degree $d \geq 2$.


title:
A diffusion and clustering-based approach for finding coherent motions
  and understanding crowd scenes

abstract:
  This paper addresses the problem of detecting coherent motions in crowd
scenes and presents its two applications in crowd scene understanding: semantic
region detection and recurrent activity mining. It processes input motion
fields (e.g., optical flow fields) and produces a coherent motion filed, named
as thermal energy field. The thermal energy field is able to capture both
motion correlation among particles and the motion trends of individual
particles which are helpful to discover coherency among them. We further
introduce a two-step clustering process to construct stable semantic regions
from the extracted time-varying coherent motions. These semantic regions can be
used to recognize pre-defined activities in crowd scenes. Finally, we introduce
a cluster-and-merge process which automatically discovers recurrent activities
in crowd scenes by clustering and merging the extracted coherent motions.
Experiments on various videos demonstrate the effectiveness of our approach.


title: Faster Bottleneck Non-crossing Matchings of Points in Convex Position

abstract:
  Given an even number of points in a plane, we are interested in matching all
the points by straight line segments so that the segments do not cross.
Bottleneck matching is a matching that minimizes the length of the longest
segment. For points in convex position, we present a quadratic-time algorithm
for finding a bottleneck non-crossing matching, improving upon the best
previously known algorithm of cubic time complexity.


title:
Neutron Beam Tests of $CsI(Na)$ and $CaF_{2}(Eu)$ Crystals for Dark
  Matter Direct Search

abstract:
  In recent decades, inorganic crystals have been widely used in dark matter
direct search experiments. To contribute to the understanding of the
capabilities of $CsI(Na)$ and $CaF_{2}(Eu)$ crystals, a mono-energetic neutron
beam is utilized to study the properties of nuclear recoils, which are expected
to be similar to signals of dark matter direct detection. The quenching factor
of nuclear recoils in $CsI(Na)$ and $CaF_{2}(Eu)$, as well as an improved
discrimination factor between nuclear recoils and ${\gamma}$ backgrounds in
$CsI(Na)$, are reported.


title: Personalized Federated Search at LinkedIn

abstract:
  LinkedIn has grown to become a platform hosting diverse sources of
information ranging from member profiles, jobs, professional groups, slideshows
etc. Given the existence of multiple sources, when a member issues a query like
"software engineer", the member could look for software engineer profiles, jobs
or professional groups. To tackle this problem, we exploit a data-driven
approach that extracts searcher intents from their profile data and recent
activities at a large scale. The intents such as job seeking, hiring, content
consuming are used to construct features to personalize federated search
experience. We tested the approach on the LinkedIn homepage and A/B tests show
significant improvements in member engagement. As of writing this paper, the
approach powers all of federated search on LinkedIn homepage.


title:
Quantum heat machines equivalence and work extraction beyond
  Markovianity, and strong coupling via heat exchangers

abstract:
  Various engine types are thermodynamically equivalent in the quantum limit of
small 'engine action'. Our previous derivation of the equivalence is restricted
to Markovian heat baths and to implicit classical work repository (e.g., laser
light in the semi-classical approximation). In this paper all the components,
baths, batteries, and engine, are explicitly taken into account. To neatly
treat non-Markovian dynamics we use mediating particles that function as a heat
exchanger. We find that on top of the previously observed equivalence there is
a higher degree of equivalence that cannot be achieved in the Markovian regime.
Next we focus on the energy transfer to the work repository. A condition for
zero entropy increase in the work repository is given. Moreover, it is shown
that in the strong coupling regime it is possible to charge a battery with
energy while reducing its entropy at the same time.


title: Branes in Gravity's Rainbow

abstract:
  In this work, we investigate the thermodynamics of black $p$-branes (BB) in
the context of Gravity's Rainbow. We investigate this using rainbow functions
that have been motivated from loop quantum gravity and $\kappa$-Minkowski
noncommutative spacetime. Then for the sake of comparison, we examine a couple
of other rainbow functions that have also appeared in the literature. We show
that, for consistency, Gravity's Rainbow imposes a constraint on the minimum
mass of the BB, a constraint that we interpret here as implying the existence
of a black $p$-brane remnant. This interpretation is supported by the
computation of the black $p$-brane's heat capacity that shows that the latter
vanishes when the Schwarzschild radius takes on a value that is bigger than its
extremal limit. We found that the same conclusion is reached for the third
version of rainbow functions treated here but not with the second one for which
only standard black $p$-brane thermodynamics is recovered.


title:
Observation of a nonradiative flat band for spoof surface plasmons in a
  metallic Lieb lattice

abstract:
  We demonstrate a nonradiative flat band for spoof surface plasmon polaritons
bounded on a structured surface with Lieb lattice symmetry in the terahertz
regime. First, we theoretically derive the dispersion relation of spoof
plasmons in a metallic Lieb lattice based on the electrical circuit model. We
obtain three bands, one of which is independent of wave vector. To confirm the
theoretical result, we numerically and experimentally observe the flat band in
transmission and attenuated total reflection configurations. We reveal that the
quality factor of the nonradiative flat-band mode decoupled from the
propagating wave is higher than that of the radiative flat-band mode. This
indicates that the nonradiative flat-band mode is three-dimensionally confined
in the lattice.


title: More on analytic bootstrap for O(N) models

abstract:
  This note is an extension of a recent work on the analytical bootstrapping of
$O(N)$ models. An additonal feature of the $O(N)$ model is that the OPE
contains trace and antisymmetric operators apart from the symmetric-traceless
objects appearing in the OPE of the singlet sector. This in addition to the
stress tensor $(T_{\mu\nu})$ and the $\phi_i\phi^i$ scalar, we also have other
minimal twist operators as the spin-1 current $J_\mu$ and the
symmetric-traceless scalar in the case of $O(N)$. We determine the effect of
these additional objects on the anomalous dimensions of the corresponding
trace, symmetric-traceless and antisymmetric operators in the large spin sector
of the $O(N)$ model, in the limit when the spin is much larger than the twist.
As an observation, we also verified that the leading order results for the
large spin sector from the $\epsilon-$expansion are an exact match with our
$n=0$ case. A plausible holographic setup for the special case when $N=2$ is
also mentioned which mimics the calculation in the CFT.


title:
Bifurcations and degenerate periodic points in a three dimensional
  chaotic fluid flow

abstract:
  Analysis of the periodic points of a conservative periodic dynamical system
uncovers the basic kinematic structure of the transport dynamics, and
identifies regions of local stability or chaos. While elliptic and hyperbolic
points typically govern such behaviour in 3D systems, degenerate (parabolic)
points play a more important role than expected. These points represent a
bifurcation in local stability and Lagrangian topology. In this study we
consider the ramifications of the two types of degenerate periodic points that
occur in a model 3D fluid flow. (1) Period-tripling bifurcations occur when the
local rotation angle associated with elliptic points is reversed, creating a
reversal in the orientation of associated Lagrangian structures. Even though a
single unstable point is created, the bifurcation in local stability has a
large influence on local transport and the global arrangement of manifolds as
the unstable degenerate point has three stable and three unstable directions,
similar to hyperbolic points, and occurs at the intersection of three
hyperbolic periodic lines. The presence of period-tripling bifurcation points
indicates regions of either chaos or confinement depending on the nature of the
associated manifold intersections. (2) The second type of bifurcation occurs
when periodic lines become tangent to local or global invariant surfaces. This
bifurcation creates both saddle-centre bifurcations which can create both
chaotic and stable regions, and period-doubling bifurcations which are a common
route to chaos in 2D systems. We provide conditions for the occurrence of these
tangent bifurcations in 3D conservative systems, as well as constraints on the
possible types of tangent bifurcation that can occur based on topological
considerations.


title:
Generalized minimum dominating set and application in automatic text
  summarization

abstract:
  For a graph formed by vertices and weighted edges, a generalized minimum
dominating set (MDS) is a vertex set of smallest cardinality such that the
summed weight of edges from each outside vertex to vertices in this set is
equal to or larger than certain threshold value. This generalized MDS problem
reduces to the conventional MDS problem in the limiting case of all the edge
weights being equal to the threshold value. We treat the generalized MDS
problem in the present paper by a replica-symmetric spin glass theory and
derive a set of belief-propagation equations. As a practical application we
consider the problem of extracting a set of sentences that best summarize a
given input text document. We carry out a preliminary test of the statistical
physics-inspired method to this automatic text summarization problem.

categories: cs.IR cond-mat.stat-mech cs.CL physics.soc-ph


title: Eutectic Growth in Two-Phase Multicomponent Alloys

abstract:
  A theory of two-phase eutectic growth for a multicomponent alloy is
presented. This theory employs the thermodynamic equilibrium at the
solid/liquid interface and thus makes it possible to use standard CALPHAD
databases to determine the effects of multicomponent phase equilibrium on
eutectic growth. Using the same hypotheses as the Jackson Hunt theory, we find
that the growth law determined for binary alloys in the Jackson Hunt theory can
be generalized to systems with N elements. In particular, a new model is
derived from this theory for ternary two-phase eutectics. The use of this model
to predict the eutectic microstructure of systems is discussed.


title: Emergent quantum mechanics without wave functions

abstract:
  We present our model of an Emergent Quantum Mechanics which can be
characterized by "realism without pre-determination". This is illustrated by
our analytic description and corresponding computer simulations of Bohmian-like
"surreal" trajectories, which are obtained classically, i.e. without the use of
any quantum mechanical tool such as wave functions. However, these trajectories
do not necessarily represent ontological paths of particles but rather mappings
of the probability density flux in a hydrodynamical sense. Modelling emergent
quantum mechanics in a high-low intesity double slit scenario gives rise to the
"quantum sweeper effect" with a characteristic intensity pattern. This
phenomenon should be experimentally testable via weak measurement techniques.


title:
Greedy Ants Colony Optimization Strategy for Solving the Curriculum
  Based University Course Timetabling Problem

abstract:
  Timetabling is a problem faced in all higher education institutions. The
International Timetabling Competition (ITC) has published a dataset that can be
used to test the quality of methods used to solve this problem. A number of
meta-heuristic approaches have obtained good results when tested on the ITC
dataset, however few have used the ant colony optimization technique,
particularly on the ITC 2007 curriculum based university course timetabling
problem. This study describes an ant system that solves the curriculum based
university course timetabling problem and the quality of the algorithm is
tested on the ITC 2007 dataset. The ant system was able to find feasible
solutions in all instances of the dataset and close to optimal solutions in
some instances. The ant system performs better than some published approaches,
however results obtained are not as good as those obtained by the best
published approaches. This study may be used as a benchmark for ant based
algorithms that solve the curriculum based university course timetabling
problem.


title: Strong Backdoors for Linear Temporal Logic

abstract:
  In the present paper we introduce the notion of strong backdoors into the
field of temporal logic for the CNF-fragment of linear temporal logic
introduced by Fisher. We study the parameterised complexity of the
satisfiability problem parameterised by the size of the backdoor. We
distinguish between backdoor detection and evaluation of backdoors into the
fragments of horn and krom formulas. Here we classify the operator fragments of
globally-operators for past or future, and the combination of both. Detection
is shown to be in FPT whereas the complexity of evaluation behaves different.
We show that for krom formulas the problem is paraNP-complete. For horn
formulas the complexity is shown to be either fixed parameter tractable or
paraNP-complete depending on the considered operator fragment.


title: Set Regularities and Feasibility Problems

abstract:
  We synthesize and unify notions of regularity, both of individual sets and of
collections of sets, as they appear in the convergence theory of projection
methods for consistent feasibility problems. Several new characterizations of
regularities are presented which shed light on the relations between seemingly
different ideas and point to possible necessary conditions for local linear
convergence of fundamental algorithms.


title:
Reinforcement Learning approach for Real Time Strategy Games Battle city
  and S3

abstract:
  In this paper we proposed reinforcement learning algorithms with the
generalized reward function. In our proposed method we use Q-learning and SARSA
algorithms with generalised reward function to train the reinforcement learning
agent. We evaluated the performance of our proposed algorithms on two real-time
strategy games called BattleCity and S3. There are two main advantages of
having such an approach as compared to other works in RTS. (1) We can ignore
the concept of a simulator which is often game specific and is usually hard
coded in any type of RTS games (2) our system can learn from interaction with
any opponents and quickly change the strategy according to the opponents and do
not need any human traces as used in previous works. Keywords : Reinforcement
learning, Machine learning, Real time strategy, Artificial intelligence.


title:
Surface terminations and layer-resolved spectroscopy in 122 iron
  pnictide superconductors

abstract:
  The surface terminations of 122-type alkaline earth metal iron pnictides
AEFe2As2 (AE = Ca, Ba) are investigated with scanning tunneling
microscopy/spectroscopy (STM/STS). Cleaving these crystals at a cryogenic
temperature yields a large majority of terminations with atomically resolved
square-root-two (rt2) or 1*2 lattice, as well as the very rare terminations
with 1*1 symmetry. By means of lattice alignment and chemical marking, we
identify these terminations as rt2-AE, 1*2-As, and rt2-Fe surfaces,
respectively. Layer-resolved spectroscopy on these terminating surfaces reveals
a well-defined superconducting gap on the As terminations, while the gap
features become weaker and absent on AE and Fe terminations respectively. The
local gap features are hardly affected by the surface reconstruction on As or
AE surface, whereas a suppression of them along with the in-gap states can be
induced by As vacancies. The emergence of two impurity resonance peaks at +-2
meV is consistent with the sign-reversal pairing symmetry. The definite
identification of surface terminations and their spectroscopic signatures shall
provide a more comprehensive understanding of the high-temperature
superconductivity in multilayered iron pnictides.


title: "Why Should I Trust You?": Explaining the Predictions of Any Classifier

abstract:
  Despite widespread adoption, machine learning models remain mostly black
boxes. Understanding the reasons behind predictions is, however, quite
important in assessing trust, which is fundamental if one plans to take action
based on a prediction, or when choosing whether to deploy a new model. Such
understanding also provides insights into the model, which can be used to
transform an untrustworthy model or prediction into a trustworthy one. In this
work, we propose LIME, a novel explanation technique that explains the
predictions of any classifier in an interpretable and faithful manner, by
learning an interpretable model locally around the prediction. We also propose
a method to explain models by presenting representative individual predictions
and their explanations in a non-redundant way, framing the task as a submodular
optimization problem. We demonstrate the flexibility of these methods by
explaining different models for text (e.g. random forests) and image
classification (e.g. neural networks). We show the utility of explanations via
novel experiments, both simulated and with human subjects, on various scenarios
that require trust: deciding if one should trust a prediction, choosing between
models, improving an untrustworthy classifier, and identifying why a classifier
should not be trusted.


title:
A Multilevel Sampling Method for Detecting Sources in a Stratified Ocean
  Waveguide

abstract:
  In the reconstruction process of sound waves in a 3D stratified waveguide, a
key technique is to effectively reduce the huge computational demand. In this
work, we propose an efficient and simple multilevel reconstruction method to
help locate the accurate position of a point source in a stratified ocean. The
proposed method can be viewed as a direct sampling method since no solutions of
optimizations or linear systems are involved. The novel method exhibits several
strengths: fast convergence, robustness against noise, advantages in
computational complexity and applicability for a very small number of
receivers.


title: Period spacings in red giants II. Automated measurement

abstract:
  The space missions CoRoT and Kepler have provided photometric data of
unprecedented quality for asteroseismology. A very rich oscillation pattern has
been discovered for red giants, including mixed modes that are used to decipher
the red giants interiors. They carry information on the radiative core of red
giant stars and bring strong constraints on stellar evolution. Since more than
15,000 red giant light curves have been observed by Kepler, we have developed a
simple and efficient method for automatically characterizing the mixed-mode
pattern and measuring the asymptotic period spacing. With the asymptotic
expansion of the mixed modes, we have revealed the regularity of the
gravity-mode pattern. The stretched periods were used to study the evenly space
periods with a Fourier analysis and to measure the gravity period spacing, even
when rotation severely complicates the oscillation spectra. We automatically
measured gravity period spacing for more than 6,100 Kepler red giants. The
results confirm and extend previous measurements made by semi-automated
methods. We also unveil the mass and metallicity dependence of the relation
between the frequency spacings and the period spacings for stars on the red
giant branch. The delivery of thousands of period spacings combined with all
other seismic and non-seismic information provides a new basis for detailed
ensemble asteroseismology.


title: On Perfect Classification and Clustering for Gaussian Processes

abstract:
  In this paper, we propose a data based transformation for
infinite-dimensional Gaussian processes and derive its limit theorem. For a
classification problem, this transformation induces complete separation among
the associated Gaussian processes. The misclassification probability of any
simple classifier when applied on the transformed data asymptotically converges
to zero. In a clustering problem using mixture models, an appropriate
modification of this transformation asymptotically leads to perfect separation
of the populations. Theoretical properties are studied for the usual $k$-means
clustering method when used on this transformed data. Good empirical
performance of the proposed methodology is demonstrated using simulated as well
as benchmark data sets, when compared with some popular parametric and
nonparametric methods for such functional data.


title:
Flat rotation curves and low velocity dispersions in KMOS star-forming
  galaxies at z~1

abstract:
  The study of the evolution of star-forming galaxies requires the
determination of accurate kinematics and scaling relations out to high
redshift. In this paper we select a sample of 18 galaxies at z~1, observed in
the H-alpha emission-line with KMOS, to derive accurate kinematics using a
novel 3D analysis technique. We use the new code 3D-Barolo, that models the
galaxy emission directly in the 3D observational space, without the need to
extract kinematic maps. This technique's major advantage is that it is not
affected by beam smearing and thus it enables the determination of rotation
velocity and intrinsic velocity dispersion, even at low spatial resolution. We
find that: 1) the rotation curves of these z~1 galaxies rise very steeply
within few kiloparsecs and remain flat out to the outermost radius and 2) the
H-alpha velocity dispersions are low, ranging from 15 to 40 km/s, which leads
to V/sigma = 3-10. These characteristics are similar to those of disc galaxies
in the local Universe. Finally, we also report no significant evolution of the
stellar-mass Tully-Fisher relation. Our results show that disc galaxies are
kinematically mature and rotation-dominated already at z~1.


title: Twisted Novikov homology of complex hypersurface complements

abstract:
  We study the twisted Novikov homology of the complement of a complex
hypersurface in general position at infinity. We give a self-contained
topological proof of the vanishing (except possibly in the middle degree) of
the twisted Novikov homology groups associated to positive cohomology classes
of degree one defined on the complement.


title: On a multiplicative version of Mumford's theorem

abstract:
  A theorem of Esnault, Srinivas and Viehweg asserts that if the Chow group of
0-cycles of a smooth complete complex variety decomposes, then the top-degree
coherent cohomology group decomposes similarly. In this note, we prove a
similar statement for Chow groups of arbitrary codimension, provided the
variety satisfies the Lefschetz standard conjecture.


title:
Some desultory remarks concerning algebraic cycles and Calabi--Yau
  threefolds

abstract:
  We study some conjectures about Chow groups of varieties of geometric genus
one. Some examples are given of Calabi-Yau threefolds where these conjectures
can be verified, using the theory of finite-dimensional motives.


title: A pathwise approach to continuous-time trading

abstract:
  This paper develops a mathematical framework for the analysis of
continuous-time trading strategies which, in contrast to the classical setting
of continuous-time mathematical finance, does not rely on stochastic integrals
or other probabilistic notions. Our purely analytic framework allows for the
derivation of a pathwise self-financial condition for continuous-time trading
strategies, which is consistent with the classical definition in case a
probability model is introduced. Our first proposition provides us with a
pathwise definition of the gain process for a large class of continuous-time,
path-dependent, self-finacing trading strategies, including the important class
of 'delta-hedging' strategies, and is based on the recently developed
'non-anticipative functional calculus'. Two versions of the statement involve
respectively continuous and c\`adl\`ag price paths. The second proposition is a
pathwise replication result that generalizes the ones obtained in the classical
framework of diffusion models. Moreover, it gives an explicit and purely
pathwise formula for the hedging error of delta-hedging strategies for
path-dependent derivatives across a given set of scenarios. We also provide an
economic justification of our main assumption on price paths.


title: A family of K3 surfaces having finite-dimensional motive

abstract:
  This short note contains an example of a 4-dimensional family of K3 surfaces
having finite-dimensional motive. Some consequences are presented, for instance
the verification of a conjecture of Voisin (concerning 0-cycles on the
self-product) for K3 surfaces in this family.


title: Some remarks on cones of partially ample divisors

abstract:
  We study the cones of q-ample divisors on smooth complex varieties. In
favourable cases, we identify a part where the closure of this cone and the nef
cone have the same boundary. This is especially interesting for Fano (or almost
Fano) varieties.


title:
Orbital selectivity of layer resolved tunneling on iron superconductor
  Ba0.6K0.4Fe2As2

abstract:
  We use scanning tunneling microscopy/spectroscopy (STM/S) to elucidate the
Cooper pairing of the iron pnictide superconductor Ba0.6K0.4Fe2As2. By a
cold-cleaving technique, we obtain atomically resolved termination surfaces
with different layer identities. Remarkably, we observe that the low-energy
tunneling spectrum related to superconductivity has an unprecedented dependence
on the layer-identity. By cross-referencing with the angle-revolved
photoemission results and the tunneling data of LiFeAs, we find that tunneling
on each termination surface probes superconductivity through selecting distinct
Fe-3d orbitals. These findings imply the real-space orbital features of the
Cooper pairing in the iron pnictide superconductors, and propose a new and
general concept that, for complex multi-orbital material, tunneling on
different terminating layers can feature orbital selectivity.


title:
Deviations in expected price impact for small transaction volumes under
  fee restructuring

abstract:
  We report on the occurrence of an anomaly in the price impacts of small
transaction volumes following a change in the fee structure of an electronic
market. We first review evidence for the existence of a master curve for price
impact on the Johannesburg Stock Exchange (JSE). On attempting to re-estimate a
master curve after fee reductions, it is found that the price impact
corresponding to smaller volume trades is greater than expected relative to
prior estimates for a range of listed stocks. We show that a master curve for
price impact can be found following rescaling by an appropriate liquidity
proxy, providing a means for practitioners to approximate price impact curves
without onerous processing of tick data.


title: Q($\lambda$) with Off-Policy Corrections

abstract:
  We propose and analyze an alternate approach to off-policy multi-step
temporal difference learning, in which off-policy returns are corrected with
the current Q-function in terms of rewards, rather than with the target policy
in terms of transition probabilities. We prove that such approximate
corrections are sufficient for off-policy convergence both in policy evaluation
and control, provided certain conditions. These conditions relate the distance
between the target and behavior policies, the eligibility trace parameter and
the discount factor, and formalize an underlying tradeoff in off-policy
TD($\lambda$). We illustrate this theoretical relationship empirically on a
continuous-state control task.


title:
Parallel Linear Search with no Coordination for a Randomly Placed
  Treasure

abstract:
  In STOC'16, Fraigniaud et al. consider the problem of finding a treasure
hidden in one of many boxes that are ordered by importance. That is, if a
treasure is in a more important box, then one would like to find it faster.
Assuming there are many searchers, the authors suggest that using an algorithm
that requires no coordination between searchers can be highly beneficial.
Indeed, besides saving the need for a communication and coordination mechanism,
such algorithms enjoy inherent robustness. The authors proceed to solve this
linear search problem in the case of countably many boxes and an adversary
placed treasure, and prove that the best speed-up possible by $k$
non-coordinating searchers is precisely $\frac{k}{4}(1+1/k)^2$. In particular,
this means that asymptotically, the speed-up is four times worse compared to
the case of full coordination.
  We suggest an important variant of the problem, where the treasure is placed
uniformly at random in one of a finite, large, number of boxes. We devise
non-coordinating algorithms that achieve a speed-up of $6/5$ for two searchers,
a speed-up of $3/2$ for three searchers, and in general, a speed-up of
$k(k+1)/(3k-1)$ for any $k \geq 1$ searchers. Thus, as $k$ grows to infinity,
the speed-up approaches three times worse compared to the case of full
coordination. Moreover, these bounds are tight in a strong sense as no
non-coordinating search algorithm for $k$ searchers can achieve better
speed-ups. We also devise non-coordinating algorithms that use only logarithmic
memory in the size of the search domain, and yet, asymptotically, achieve the
optimal speed-up. Finally, we note that all our algorithms are extremely simple
and hence applicable.


title:
Bjorken flow in one-dimensional relativistic magnetohydrodynamics with
  magnetization

abstract:
  We study the one-dimensional, longitudinally boost-invariant motion of an
ideal fluid with infinite conductivity in the presence of a transverse magnetic
field, i.e., in the ideal transverse magnetohydrodynamical limit. In an
extension of our previous work Roy et al., [Phys. Lett. B 750, 45 (2015)], we
consider the fluid to have a non-zero magnetization. First, we assume a
constant magnetic susceptibility $\chi_{m}$ and consider an ultrarelativistic
ideal gas equation of state. For a paramagnetic fluid (i.e., with
$\chi_{m}>0$), the decay of the energy density slows down since the fluid gains
energy from the magnetic field. For a diamagnetic fluid (i.e., with
$\chi_{m}<0$), the energy density decays faster because it feeds energy into
the magnetic field. Furthermore, when the magnetic field is taken to be
external and to decay in proper time $\tau$ with a power law $\sim\tau^{-a}$,
two distinct solutions can be found depending on the values of $a$ and
$\chi_m$. Finally, we also solve the ideal magnetohydrodynamical equations for
one-dimensional Bjorken flow with a temperature-dependent magnetic
susceptibility and a realistic equation of state given by lattice-QCD data. We
find that the temperature and energy density decay more slowly because of the
non-vanishing magnetization. For values of the magnetic field typical for
heavy-ion collisions, this effect is, however, rather small. Only for magnetic
fields which are about an order of magnitude larger than expected for heavy-ion
collisions, the system is substantially reheated and the lifetime of the quark
phase might be extended.


title:
Transverse flow induced by inhomogeneous magnetic fields in the Bjorken
  expansion

abstract:
  We investigate the magnetohydrodynamics in the presence of an external
magnetic field following the power-law decay in proper time and having spatial
inhomogeneity characterized by a Gaussian distribution in one of transverse
coordinates under the Bjorken expansion. The leading-order solution is obtained
in the weak-field approximation, where both energy density and fluid velocity
are modified. It is found that the spatial gradient of the magnetic field
results in transverse flow, where the flow direction depends on the decay
exponents of the magnetic field. We suggest that such a magnetic-field-induced
effect might influence anisotropic flow in heavy ion collisions.


title: Constructive Patterns of Logical Truth

abstract:
  The simplified linguistic relation between syntax and semantics as intrinsic
property of classic Arabic motivates a dedicated look at P vs. NP in light of
efforts and solutions presented by ancient Arab- and Muslim scholars to
facilitate logical- and mathematical deduction. In Islamic Jurisprudence (Fikh)
it has recently been shown [Abdelwahab et al. 2014] that if a formal system
expressing Fikh is chosen in such a way that it is both, logically complete and
decidable, the question of a complete and consistent legislation is decidable.
If this formal Fikh-system is additionally chosen to be at least as expressive
as propositional logic, the deduction of detailed sentences is efficient while
the deduction of general rules is NP-complete. Further investigation reveals
that ancient scholars adopted a very efficient approach for checking the
validity of assertions with regard to both, language and logical argument which
was mainly characterized by the extensive use of syntactical patterns already
existent in input-variables. Accordingly, this paper introduces efficient
pattern-oriented procedures for 3-SAT as well as 2-approximation algorithms for
MinFBDD. It opens up the possibility of constructing polynomial sized FBDDs for
all Boolean functions expressed in a compact way. Eventually, an application of
this new 3-SAT-solver is shown to enable polynomial upper bounds of the number
of nodes in FBDDs constructed for finite projective planes problems overhauling
the currently known exponential lower bounds.


title: Role of Arsenic in Iron-based Superconductivity at Atomic Scale

abstract:
  In iron-based superconductors, a unique tri-layer Fe-As (Se, Te, P) plays an
essential role in controlling the electronic properties, especially the Cooper
pairing interaction. Here we use scanning tunneling microscopy/spectroscopy
(STM/S) to investigate the role of arsenic atom in superconducting
Ba0.4K0.6Fe2As2 by directly breaking and restoring the Fe-As structure at
atomic scale. After the up-As-layer peeled away, the tunneling spectrum of the
exposed iron surface reveals a shallow incoherent gap, indicating a severe
suppression of superconductivity without arsenic covering. When a pair of
arsenic atoms is placed on such iron surface, a localized topographic feature
is formed due to Fe-As orbital hybridization, and the superconducting coherent
peaks recover locally with the gap magnitude the same as that on the iron-layer
fully covered by arsenic. These observations unravel the Fe-As interactions on
an atomic scale and imply its essential roles in the iron-based
superconductivity.


title: Local explosion in self-similar growth-fragmentation processes

abstract:
  Markovian growth-fragmentation processes describe a family of particles which
can grow larger or smaller with time, and occasionally split in a conservative
manner. They were introduced in a work of Bertoin, where special attention was
given to the self-similar case. A Malthusian condition was notably given under
which the process does not locally explode, in the sense that for all times,
the masses of all the particles can be listed in non-increasing order. Our main
result in this work states the converse: when this condition is not verified,
then the growth-fragmentation process explodes almost surely. Our proof
involves using the additive martingale to bias the probability measure and
obtain a spine decomposition of the process, as well as properties of
self-similar Markov processes.


title:
Periodic transmission peak splitting in one dimensional disordered
  photonic structures

abstract:
  In the present paper we present ways to modulate the periodic transmission
peaks arising in disordered one dimensional photonic structures with hundreds
of layers. Disordered structures in which the optical length nd (n is the
refractive index and d the layer thickness) is the same for each layer show
regular peaks in their transmission spectra. A proper variation of the optical
length of the layers leads to a splitting of the transmission peaks. Notably,
the variation of the occurrence of high and low refractive index layers, gives
a tool to tune also the width of the peaks. These results are of highest
interest for optical application, such as light filtering, where the manifold
of parameters allows a precise design of the spectral transmission ranges.


title: Local And 2-Local Derivations On Algebras Of Measurable Operators

abstract:
  The present paper presents a survey of some recent results devoted to
derivations, local derivations and 2-local derivations on various algebras of
measurable operators affiliated with von Neumann algebras. We give a complete
description of derivation on these algebras, except the case where the von
Neumann algebra is of type II$_1$. In the latter case the result is obtained
under an extra condition of measure continuity of derivations. Local and
2-local derivations on the above algebras are also considered. We give
sufficient conditions on a von Neumann algebra $M$, under which every local or
2-local derivation on the algebra of measurable operators affiliated with $M$
is automatically becomes a derivation. We also give examples of commutative
algebras of measurable operators admitting local and 2-local derivations which
are not derivations.


title: The Brownian limit of separable permutations

abstract:
  We study random uniform permutations in an important class of
pattern-avoiding permutations: the separable permutations. We describe the
asymptotics of the number of occurrences of any fixed given pattern in such a
random permutation in terms of the Brownian excursion. In the recent
terminology of permutons, our work can be interpreted as the convergence of
uniform random separable permutations towards a "Brownian separable permuton".


title: Cooper Pairing and Phase Coherence in Iron Superconductor Fe1+x(Te,Se)

abstract:
  The Cooper pairing and phase coherence are two fundamental aspects of
superconductivity. Due to breaking time reversal symmetry, magnetic impurities
are detrimental to superconductivity, yet microscopically how they affect the
pairing strength and phase coherence in a real material is less understood.
Recently we observed a robust zero-energy bound state at an interstitial Fe
impurity (IFI) in superconducting Fe1+x(Te,Se), signifying intense impurity
scattering. Here we report a comprehensive study, using scanning tunnelling
microscopy/spectroscopy (STM/S) technique, of the global effects of IFIs on the
ground state of Fe1+x(Te,Se) over a wide range of IFI concentration x. Our high
resolution tunnelling spectroscopy and quasi-particle interference data at very
low temperature demonstrate that IFIs hardly affect the electron pairing
strength, while they cause significant decoherence of Cooper pairs in
precedence of the Coulomb correlation, eventually driving the ground state of
the system from strong-coupling-superconductor to diffusive-metal with
incoherent electron pairs.


title:
Energy correlations of photon pairs generated by a silicon microring
  resonator probed by Stimulated Four Wave Mixing

abstract:
  Compact silicon integrated devices, such as micro-ring resonators, have
recently been demonstrated as efficient sources of quantum correlated photon
pairs. The mass production of integrated devices demands the implementation of
fast and reliable techniques to monitor the device performances. In the case of
time-energy correlations, this is particularly challenging, as it requires high
spectral resolution that is not currently achievable in coincidence
measurements. Here we reconstruct the joint spectral density of photons pairs
generated by spontaneous four-wave mixing in a silicon ring resonator by
studying the corresponding stimulated process, namely stimulated four wave
mixing. We show that this approach, featuring high spectral resolution and
short measurement times, allows one to discriminate between nearly-uncorrelated
and highly-correlated photon pairs.


title: Simulations of coalescing black holes

abstract:
  We describe the methods and results of numerical simulations of coalescing
black holes. The simulation in dynamical spacetime covers the inspiral, merger,
and ringdown phases. We analyze the emission of gravitational waves and
properties of a black hole being the merger product. We discuss the results in
the context of astrophysical environment of black holes that exist in the
Universe.


title: Radial pulsation as a function of hydrogen abundance

abstract:
  Using linear non-adabatic pulsation analysis, we explore the radial-mode
(p-mode) stability of stars across a wide range of mass (0.2 <= M <= 50 Msun),
composition (0 <= X <= 0.7, Z=0.001, 0.02), effective temperature (3 000 <=
T_eff <= 40 000 K), and luminosity (0.01 <= L/M <= 100,000 solar units).We
identify the instability boundaries associated with low- to high-order radial
oscillations (0 <= n <=16). The instability boundaries are a strong function of
both composition and radial order (n). With decreasing hydrogen abundance we
find that i) the classical blue edge of the Cepheid instability strip shifts to
higher effective temperature and luminosity, and ii) high-order modes are more
easily excited and small islands of high radial-order instability develop, some
of which correspond with real stars. Driving in all cases is by the classical
kappa-mechanism and/or strange modes. We identify regions of parameter space
where new classes of pulsating variable may, in future, be discovered. The
majority of these are associated with reduced hydrogen abundance in the
envelope; one has not been identified previously.


title:
Transport studies of LPA electron beam towards the FEL amplification at
  COXINEL

abstract:
  Laser Plasma Acceleration (LPA) [1] is an emerging concept enabling to
generate electron beams with high energy, high peak current and small
transverse emittance within a very short distance. The use of LPA can be
applied to the Free Electron Laser (FEL) [2] case in order to investigate
whether it is suitable for the light amplification in the undulator. However,
capturing and guiding of such beams to the undulator is very challenging,
because of the large divergence and high energy spread of the electron beams at
the plasma exit, leading to large chromatic emittances. A specific beam
manipulation scheme was recently proposed for the COXINEL (Coherent X-ray
source inferred from electrons accelerated by laser) setup, which makes an
advantage from the intrinsically large chromatic emittance of such beams [3].
The electron beam transport is studied using two simulation codes: a SOLEIL
in-house one and ASTRA [4]. The influence of the collective effects on the
electron beam performance is also examined.


title: Formulation of small-strain magneto-elastic problems

abstract:
  Despite of the topical engineering need and all scientific investments, the
mathematical formulation of modeling elastic deformations in magnetic systems
is not yet fully established. Often, especially in electrical engineering
applications, a model assuming small (infinitesimal) strains seems sufficient.
To express such small-strain magneto-elastic problems in a suitable form for
discretization methods, we present here a formulation in the framework of
differential geometry. The given analysis shows algebraic similarity between
small-strain elasticity and magnetism. This suggests that a class of magnetic,
elastic, and magneto-elastic problems may be modeled in the same algebraic
category, constituting suitable domain for discretizations.


title: Strongly Universal Reversible Gate Sets

abstract:
  It is well-known that the Toffoli gate and the negation gate together yield a
universal gate set, in the sense that every permutation of $\{0,1\}^n$ can be
implemented as a composition of these gates. Since every bit operation that
does not use all of the bits performs an even permutation, we need to use at
least one auxiliary bit to perform every permutation, and it is known that one
bit is indeed enough. Without auxiliary bits, all even permutations can be
implemented. We generalize these results to non-binary logic: If $A$ is a
finite set of odd cardinality then a finite gate set can generate all
permutations of $A^n$ for all $n$, without any auxiliary symbols. If the
cardinality of $A$ is even then, by the same argument as above, only even
permutations of $A^n$ can be implemented for large $n$, and we show that indeed
all even permutations can be obtained from a finite universal gate set. We also
consider the conservative case, that is, those permutations of $A^n$ that
preserve the weight of the input word. The weight is the vector that records
how many times each symbol occurs in the word. It turns out that no finite
conservative gate set can, for all $n$, implement all conservative even
permutations of $A^n$ without auxiliary bits. But we provide a finite gate set
that can implement all those conservative permutations that are even within
each weight class of $A^n$.


title: Generalising Wigner's theorem

abstract:
  We analyse linear maps of operator algebras $\mathcal{B}_H(\mathcal{H})$
mapping the set of rank-$k$ projectors onto the set of rank-$l$ projectors
surjectively. We give a complete characterisation of such maps for prime $n =
\dim\mathcal{H}$. The solution is known for $k=l=1$ as the Wigner's theorem.


title: Stationary bubbles: information loss paradox?

abstract:
  The main purpose of this work is to build classically stationary bubbles,
within the thin-shell formalism, which are unstable under quantum effects; they
either collapse into a black hole or expand. Thus, the final state can be
thought of a superposition of geometries. We point out that, from a quantum
mechanical point of view, there is no issue with a loss of information in such
configuration. A classical observer sees a definite geometry and, hence, finds
an effective loss of information. Although it does not cover all possible
cases, we emphasise the role of semi-classical gravitational effects, mediated
by instatons, in alleviating/solving the information loss paradox.


title:
The decays $\tau \rightarrow (\eta,\eta') K^{-} \nu_{\tau}$ in the
  extended Nambu-Jona-Lasinio model

abstract:
  The decays $\tau \rightarrow (\eta,\eta') K^{-} \nu_{\tau}$ are described in
the framework of the extended Nambu-Jona-Lasinio model. Both full and
differential widths of these decays are calculated. The vector and scalar
channels are considered. In the vector channels, the subprocesses with
intermediate $K^{*}(892)$ and $K^{*}(1410)$ mesons play the main role. In the
scalar channels, the subprocesses with intermediate $K_{0}^{*}(800)$ and
$K_{0}^{*}(1430)$ mesons are taken into account. Scalar channels play a less
important role in calculation of the full width of the decay $\tau \rightarrow
(\eta,\eta') K^{-} \nu_{\tau}$. The obtained results are in satisfactory
agreement with the experimental data.


title: The combinatorics of overlapping genes

abstract:
  Overlapping genes exist in all domains of life and are much more abundant
than expected at their first discovery in the late 1970s. Assuming that the
reference gene is read in frame +0, an overlapping gene can be encoded in two
reading frames in the sense strand, denoted by +1 and +2, and in three reading
frames in the opposite strand, denoted by -0, -1 and -2. This motivated
numerous researchers to study the constraints induced by the genetic code on
the various overlapping frames, mostly based on information theory. Our focus
in this paper is on the constraints induced on two overlapping genes in terms
of amino acids, as well as polypeptides. We show that simple linear constraints
bind the amino acid composition of two proteins encoded by overlapping genes.
Novel constraints are revealed when polypeptides are considered, and not just
single amino acids. For example, in double-coding sequences with an overlapping
reading frame -2, each Tyrosine (denoted as Tyr or Y) in the overlapping frame
overlaps a Tyrosine in the reference frame +0 (and reciprocally), whereas
specific words (e.g. YY) never occur. We thus distinguish between null
constraints (YY = 0 in frame -2) and non-null constraints (Y in frame +0 <=> Y
in frame -2). Our equivalence-based constraints are symmetrical and thus enable
the characterization of the joint composition of overlapping proteins. We
describe several formal frameworks and a graph algorithm to characterize and
compute these constraints. These results yield support for understanding the
mechanisms and evolution of overlapping genes, and for developing novel
overlapping gene detection methods.


title:
Short-range phase coherence and origin of the 1T-TiSe2 charge density
  wave

abstract:
  The impact of variable Ti self-doping on the 1T-TiSe2 charge density wave
(CDW) is studied by scanning tunneling microscopy. Supported by density
functional theory we show that agglomeration of intercalated-Ti atoms acts as
preferential nucleation centers for the CDW that breaks up in phaseshifted CDW
domains whose size directly depends on the intercalated-Ti concentration and
which are separated by atomically-sharp phase boundaries. The close
relationship between the diminution of the CDW domain size and the
disappearance of the anomalous peak in the temperature dependent resistivity
allows to draw a coherent picture of the 1T-TiSe2 CDW phase transition and its
relation to excitons.


title:
Simulating the Diffference between a DES and a Simple Railgun using
  SPICE

abstract:
  A DES railgun increases the launch efficiency when compared to a simple
railgun setup. In a NGSPICE-simulation a DES and a simple railgun setup
connected to an existing 10-MJ capacitor based power supply are compared.
Important parameters like velocity, power and efficiency are used to quantify
the performance gain, when using the mechanically more complex DES setup. The
results of this study were used to select the simple railgun setup as the
design for a new barrel to the 10-MJ power supply.


title:
Encoding Distortion Modeling For DWT-Based Wireless EEG Monitoring
  System

abstract:
  Recent advances in wireless body area sensor net- works leverage wireless and
mobile communication technologies to facilitate development of innovative
medical applications that can significantly enhance healthcare services and
improve quality of life. Specifically, Electroencephalography (EEG)-based
applications lie at the heart of these promising technologies. However, the
design and operation of such applications is challenging. Power consumption
requirements of the sensor nodes may turn some of these applications
impractical. Hence, implementing efficient encoding schemes are essential to
reduce power consumption in such applications. In this paper, we propose an
analytical distortion model for the EEG-based encoding systems. Using this
model, the encoder can effectively reconfigure its complexity by adjusting its
control parameters to satisfy application constraints while maintaining
reconstruction accuracy at the receiver side. The simulation results illustrate
that the main parameters that affect the distortion are compression ratio and
filter length of the considered DWT-based encoder. Furthermore, it is found
that the wireless channel variations have a significant influence on the
estimated distortion at the receiver side.


title: Dynamic portfolio selection without risk-free assets

abstract:
  We consider the mean--variance portfolio optimization problem under the game
theoretic framework and without risk-free assets. The problem is solved
semi-explicitly by applying the extended Hamilton--Jacobi--Bellman equation.
Although the coefficient of risk aversion in our model is a constant, the
optimal amounts of money invested in each stock still depend on the current
wealth in general. The optimal solution is obtained by solving a system of
ordinary differential equations whose existence and uniqueness are proved and a
numerical algorithm as well as its convergence speed are provided. Different
from portfolio selection with risk-free assets, our value function is quadratic
in the current wealth, and the equilibrium allocation is linearly sensitive to
the initial wealth. Numerical results show that this model performs better than
both the classical one and the variance model in a bull market.


title:
Stochastic Process Bandits: Upper Confidence Bounds Algorithms via
  Generic Chaining

abstract:
  The paper considers the problem of global optimization in the setup of
stochastic process bandits. We introduce an UCB algorithm which builds a
cascade of discretization trees based on generic chaining in order to render
possible his operability over a continuous domain. The theoretical framework
applies to functions under weak probabilistic smoothness assumptions and also
extends significantly the spectrum of application of UCB strategies. Moreover
generic regret bounds are derived which are then specialized to Gaussian
processes indexed on infinite-dimensional spaces as well as to quadratic forms
of Gaussian processes. Lower bounds are also proved in the case of Gaussian
processes to assess the optimality of the proposed algorithm.


title: Peculiarities of {\alpha}-element abundances in Galactic open clusters

abstract:
  A catalog compiling the parameters of 346 open clusters, including their
metallicities, positions, ages, and velocities has been composed. The elements
of the Galactic orbits for 272 of the clusters have been calculated.
Spectroscopic determinations of the relative abundances, [el/Fe], for 14
elements synthesized in various nuclear processes averaged over data from 109
publications are presented for 90 clusters. Since no systematic effects
distorting the relative abundances of the studied elements in these clusters
have been found, these difference suggest real differences between clusters
with high, elongated orbits and field stars. In particular, this supports the
earlier conclusion, based on an analysis of the elements of the Galactic
orbits, that some clusters formed as a result of interactions between
high-velocity, metal-poor clouds and the interstellar medium of the Galactic
thin disk. On average, clusterswith high, elongated orbits and metallicities
${\rm [Fe/H]} < - 0.1$ display lower relative abundances of the primary \'a
elements than do field stars. The low [O,Mg/Fe] ratios of these clusters can be
understood if the high-velocity clouds that gave rise to them were formed of
interstellar material from regions where the star-formation rate and/or the
masses of Type II supernovae were lower than near the Galactic plane. It is
also shown that, on average, the relative abundances of the primary
$\alpha$-elements are higher in relatively metal-rich clusters with high,
elongated orbits than in field stars. This can be understood if clusters with
${\rm [Fe/H]} > - 0.1$ formed as a result of interactions between metal-rich
clouds with intermediate velocities and the interstellar medium of the Galactic
disk; such clouds could form from returning gas in a so-called "Galactic
fountain".


title: Minimal surfaces with micro-oscillations

abstract:
  We show that there are minimal graphs in R^{n+1} whose intersection with the
portion of the horizontal hyperplane contained in the unit ball has any
prescribed geometry, up to a small deformation. The proof hinges on the
construction of minimal graphs that are almost flat but have small oscillations
whose geometry we can control.


title: Optical switching of electron transport in a waveguide-QED system

abstract:
  Electron switching in waveguides coupled to a photon cavity is found to be
strongly influenced by the photon energy and polarization. Therefore, the
charge dynamics in the system is investigated in two different regimes, for
off- and on-resonant photon fields. In the off-resonant photon field, the
photon energy is smaller than the energy spacing between the first two lowest
subbands of the waveguide system, the charge splits between the waveguides
implementing a $\sqrt{\rm NOT}$-quantum logic gate action. In the on-resonant
photon field, the charge is totally switched from one waveguide to the other
due to the appearance of photon replica states of the first subband in the
second subband region instigating a quantum-NOT transition.In addition, the
importance of the photon polarization to control the charge motion in the
waveguide system is demonstrated.The idea of charge switching in electronic
circuits may serve to built quantum bits.


title:
Performance Analysis of RFDMRP:River Formation Dynamics based Multi-Hop
  Routing Protocol in WSNs

abstract:
  In Wireless sensor networks, sensor nodes sense the data from environment
according to its functionality and forwards to its base station. This process
is called Data collection. The Data collection process is done either directly
or by multi-hop routing. In direct routing, every sensor node directly
transfers its sensed data to base station which has an impact on energy
consumption from sensor node due to the far distance between the sensor node
and base station. In multi-hop routing, the sensed data is relayed through
multiple nodes to the base station, it consumes less energy. This paper
presents and analyzes the performance of a data collection routing protocol
called RFDMRP: River Formation Dynamics based multi-hop routing protocol. The
performance of RFDMRP is tested and analyzed for network parameters such as
Network lifetime, Energy usage, and Node density & data aggregation impact on
network lifetime. The simulated results are compared with two algorithms LEACH
and MOD_LEACH. The comparison reveals that the proposed algorithm performs
better than LEACH and MOD_LEACH with respect to Network lifetime.


title: Optimizing Gaze Direction in a Visual Navigation Task

abstract:
  Navigation in an unknown environment consists of multiple separable subtasks,
such as collecting information about the surroundings and navigating to the
current goal. In the case of pure visual navigation, all these subtasks need to
utilize the same vision system, and therefore a way to optimally control the
direction of focus is needed. We present a case study, where we model the
active sensing problem of directing the gaze of a mobile robot with three
machine vision cameras as a partially observable Markov decision process
(POMDP) using a mutual information (MI) based reward function. The key aspect
of the solution is that the cameras are dynamically used either in monocular or
stereo configuration. The benefits of using the proposed active sensing
implementation are demonstrated with simulations and experiments on a real
robot.


title:
Role of multi-level states on quantum-dot emission in photonic-crystal
  cavities

abstract:
  Semiconductor quantum dots embedded in photonic-crystal nanostructures have
been the subject of intense study. In this context, quantum dots are often
considered to be simple two-level emitters, i.e., the complexities arising from
the internal finestructure are neglected. We show that due to the intricate
spatial variations of the electric field polarization found in photonic
crystal, the two orthogonal finestructure states of quantum dots in general
both couple significantly to a cavity mode, implying that the two-level
description is not sufficient. As a consequence the emission dynamics and
spectra, which are often recorded in experiments, are modified both in the
weak- and strong-coupling regimes. The proposed effects are found to be
significant for system parameters of current state-of-the-art photonic-crystal
cavities.


title: Contextual Media Retrieval Using Natural Language Queries

abstract:
  The widespread integration of cameras in hand-held and head-worn devices as
well as the ability to share content online enables a large and diverse visual
capture of the world that millions of users build up collectively every day. We
envision these images as well as associated meta information, such as GPS
coordinates and timestamps, to form a collective visual memory that can be
queried while automatically taking the ever-changing context of mobile users
into account. As a first step towards this vision, in this work we present
Xplore-M-Ego: a novel media retrieval system that allows users to query a
dynamic database of images and videos using spatio-temporal natural language
queries. We evaluate our system using a new dataset of real user queries as
well as through a usability study. One key finding is that there is a
considerable amount of inter-user variability, for example in the resolution of
spatial relations in natural language utterances. We show that our retrieval
system can cope with this variability using personalisation through an online
learning-based retrieval formulation.


title:
Deconvolutional Feature Stacking for Weakly-Supervised Semantic
  Segmentation

abstract:
  A weakly-supervised semantic segmentation framework with a tied
deconvolutional neural network is presented. Each deconvolution layer in the
framework consists of unpooling and deconvolution operations. 'Unpooling'
upsamples the input feature map based on unpooling switches defined by
corresponding convolution layer's pooling operation. 'Deconvolution' convolves
the input unpooled features by using convolutional weights tied with the
corresponding convolution layer's convolution operation. The
unpooling-deconvolution combination helps to eliminate less discriminative
features in a feature extraction stage, since output features of the
deconvolution layer are reconstructed from the most discriminative unpooled
features instead of the raw one. This results in reduction of false positives
in a pixel-level inference stage. All the feature maps restored from the entire
deconvolution layers can constitute a rich discriminative feature set according
to different abstraction levels. Those features are stacked to be selectively
used for generating class-specific activation maps. Under the weak supervision
(image-level labels), the proposed framework shows promising results on lesion
segmentation in medical images (chest X-rays) and achieves state-of-the-art
performance on the PASCAL VOC segmentation dataset in the same experimental
condition.


title: Fast strategies in biased Maker--Breaker games

abstract:
  We study the biased $(1:b)$ Maker--Breaker positional games, played on the
edge set of the complete graph on $n$ vertices, $K_n$. Given Breaker's bias
$b$, possibly depending on $n$, we determine the bounds for the minimal number
of moves, depending on $b$, in which Maker can win in each of the two standard
graph games, the Perfect Matching game and the Hamilton Cycle game.


title:
On the theory of electric double layer with explicit account of a
  polarizable co-solvent

abstract:
  We present a continuation of our theoretical research into the influence of
co-solvent polarizability on a differential capacitance of the electric double
layer [EPL 111, 28002 (2015)]. We formulate a modified Poisson-Boltzmann
theory, using the formalism of density functional approach on the level of
local density approximation taking into account the electrostatic interactions
of ions and co-solvent molecules as well as their excluded volume. We derive
the modified Poisson-Boltzmann equation, considering the three-component
symmetric lattice gas model as a reference system and minimizing the grand
thermodynamic potential with respect to the electrostatic potential. We apply
present modified Poisson-Boltzmann equation to the electric double layer
theory.


title:
A statistical theory of coil-to-globule-to-coil transition of a polymer
  chain in the mixture of good solvents

abstract:
  We present an off-lattice statistical model of a single polymer chain in
mixed solvent media. Taking into account a polymer conformational entropy,
renormalization of solvent composition near the polymer backbone, the universal
intermolecular excluded volume and Van-der-Waals interactions within the
self-consistent field theory the reentrant coil-to-globule-to-coil transition
(co-nonsolvency) has been described in this paper. For convenience we split the
system volume in two parts: the volume occupied by the polymer chain and the
volume of bulk solution. Considering the equilibrium between two sub-volumes,
the polymer solvation free energy as a function of radius of gyration and
co-solvent mole fraction within internal polymer volume has been obtained.
Minimizing the free energy of solvation with respect to its arguments, we show
two qulitatively different regimes of co-nonsolvency. Namely, at sufficiently
high temperature a reentrant coil-to-globule-to-coil transition proceeds
smoothly. On the contrary, when the temperature drops below a certain threshold
value a coil-globule transition occurs in the regime of first-order phase
transition, i.e., discontinuous changes of the radius of gyration and the local
co-solvent mole fraction near the polymer backbone. We show that, when the
collapse of polymer chain takes place, the entropy and enthalpy contributions
to the solvation free energy of globule strongly grow. From the first
principles of statistical thermodynamics we confirm earlier speculations based
on the MD simulations results that the co-nonsolvency is the essentially
enthalpic-entropic effect and caused by enthalpy-entropy compensation. We show
that the temperature dependences of solution heat capacity change due to the
solvation of polymer chain are in qualitative agreement with the Differential
scanning calorimetry data for PNIPAM in aqueous methanol.


title: Maximally extended sl(2|2) as a quantum double

abstract:
  We derive the universal R-matrix of the quantum-deformed enveloping algebra
of centrally extended sl(2|2) using Drinfeld's quantum double construction. We
are led to enlarging the algebra by additional generators corresponding to an
sl(2) automorphism. For this maximally extended algebra we construct a
consistent Hopf algebra structure where the extensions exhibit several uncommon
features. We determine the corresponding universal R-matrix containing some
non-standard functions. Curiously, this Hopf algebra has one extra deformation
parameter for which the R-matrix does not factorize into products of
exponentials.


title: Quantum Stiefel manifolds

abstract:
  Quantum analogs of Stiefel manifolds $SU_{q}(n)/SU_q(n-m)$ were introduced by
Podkolzin \& Vainerman. The underlying $C^*$-algebra $C(SU_{q}(n)/SU_q(n-m))$
can be described as the $C^*$-subalgebra of $C(SU_q(n))$ generated by elements
of last $m$ rows of the fundamental matrix of $SU_q(n)$. Using $R$-matrix of
type $A_{n-1}$, one can find certain relations involving elements of last $m$
rows only. In this paper, by analyzing these relations and using a result of
Neshveyev \& Tuset, we establish $C(SU_{q}(n)/SU_q(n-m))$ as a universal
$C^*$-algbera given by finite sets of generators and relations.


title: A lower bound to the spectral threshold in curved quantum layers

abstract:
  We derive a lower bound to the spectral threshold of the Dirichlet Laplacian
in tubular neighbourhoods of constant radius about complete surfaces. This
lower bound is given by the lowest eigenvalue of a one-dimensional operator
depending on the radius and principal curvatures of the reference surface.
Moreover, we show that it is optimal if the reference surface is non-negatively
curved.


title:
Observation of geometric parametric instability induced by the periodic
  spatial self-imaging of multimode waves

abstract:
  Spatio-temporal mode coupling in highly multimode physical systems permits
new routes for exploring complex instabilities and forming coherent wave
structures. We present here the first experimental demonstration of multiple
geometric parametric instability sidebands, generated in the frequency domain
through resonant space-time coupling, owing to the natural periodic spatial
self-imaging of a multimode quasi-continuous-wave beam in a standard
graded-index multimode fiber. The input beam was launched in the fiber by means
of an amplified microchip laser emitting sub-nanosecond pulses at 1064 nm. The
experimentally observed frequency spacing among sidebands agrees well with
analytical predictions and numerical simulations. The first order peaks are
located at the considerably large detuning of 123.5 THz from the pump. These
results open the remarkable possibility to convert a near-infrared laser
directly into a broad spectral range spanning visible and infrared wavelengths,
by means of a single resonant parametric nonlinear effect occurring in the
normal dispersion regime. As a further evidence of our strong space-time
coupling regime, we observed the striking effect that all of the different
sideband peaks were carried by a well-defined and stable bell-shaped spatial
profile.


title:
Influence of the substrate material on the knife-edge based profiling of
  tightly focused light beams

abstract:
  The performance of the knife-edge method as a beam profiling technique for
tightly focused light beams depends on several parameters, such as the material
and height of the knife-pad as well as the polarization and wavelength of the
focused light beam under study. Here we demonstrate that the choice of the
substrate the knife-pads are fabricated on has a crucial influence on the
reconstructed beam projections as well. We employ an analytical model for the
interaction of the knife-pad with the beam and report good agreement between
our numerical and experimental results. Moreover, we simplify the analytical
model and demonstrate, in which way the underlying physical effects lead to the
apparent polarization dependent beam shifts and changes of the beamwidth for
different substrate materials and heights of the knife-pad.


title:
The electronic structure and intervalley coupling of artificial and
  genuine graphene superlattice

abstract:
  A so-called artificial graphene is an artificial material whose low-energy
carriers are described by the massless Dirac equation. Applying a periodic
potential with triangular symmetry to a two-dimensional electron gas is one way
to make such a material. According to recent experimental results, it is now
possible to realize an artificial graphene in the lab and to even apply an
additional lateral, one-dimensional periodic potential to it. We name the
latter system an artificial graphene superlattice in order to distinguish it
from a genuine graphene superlattice made from graphene. In this study, we
investigate the electronic structure of artificial graphene superlattices,
which exhibit the emergence of energy band gaps, merging and splitting of the
Dirac points, etc. Then, from a similar investigation on genuine graphene
superlattices, we show that many of these features originate from the coupling
between Dirac fermions residing in two different valleys, the intervalley
coupling. Furthermore, contrary to previous studies, we find that the effects
of intervalley coupling on the electronic structure cannot be ignored no matter
how long the spatial period of the superlattice is.


title:
Jacob's ladders, $\mathcal{Z}_{\zeta,Q^2}$-transformation of real
  elementary functions and telegraphic signals generated by the power functions

abstract:
  In this paper we show that the $\mathcal{Z}_{\zeta,Q^2}$-transformation of
every unbounded signal based on increasing power function is a telegraphic
signal, i.e. the unit rectangular signal.


title: On the Density of non-Simple 3-Planar Graphs

abstract:
  A \emph{$k$-planar graph} is a graph that can be drawn in the plane such that
every edge is crossed at most $k$ times. For $k \leq 4$, Pach and T\'oth proved
a bound of $(k+3)(n-2)$ on the total number of edges of a $k$-planar graph,
which is tight for $k=1,2$. For $k=3$, the bound of $6n-12$ has been improved
to $\frac{11}{2}n-11$ and has been shown to be optimal up to an additive
constant for simple graphs. In this paper, we prove that the bound of
$\frac{11}{2}n-11$ edges also holds for non-simple $3$-planar graphs that admit
drawings in which non-homotopic parallel edges and self-loops are allowed.
Based on this result, a characterization of \emph{optimal $3$-planar graphs}
(that is, $3$-planar graphs with $n$ vertices and exactly $\frac{11}{2}n-11$
edges) might be possible, as to the best of our knowledge the densest known
simple $3$-planar is not known to be optimal.


title:
Peculiarities of the abundances of neutron-capture elements in Galactic
  open clusters

abstract:
  The properties of the relative abundances of rapid and slow neutron-capture
elements are studied using a catalog containing spectroscopic abundance
determinations for 14~elements produced in various nuclear-synthesis processes
for 90~open clusters. The catalog also contains the positions, ages,
velocities, and elements of the Galactic orbits of the clusters. The relative
abundances of both $r$-elements (Eu) and $s$-elements (Y, Ba, La, and Ce) in
clusters with high, elongated orbits and in field stars of the Galactic thin
disk display different dependences on metallicity, age, Galactocentric
distance, and the elements of the Galactic orbits, supporting the view that
these objects have different natures. In young clusters, not only barium, but
also the three other studied $s$-elements display significantly higher relative
abundances than field stars of the same metallicity. The relative abundances of
Eu are lower in high-metallicity clusters (${\rm [Fe/H]} > -0.1$) with high,
elongated orbits than in field giants, on average, while the [Eu/Fe] ratios in
lower-metallicity clusters are the same as those in field stars, on average,
although with a large scatter. The metallicity dependence of the [O, Mg/Eu]
ratios in clusters with high, elongated orbits and in field stars are
substantially different. These and other described properties of the Eu
abundances, together with the properties of the abundances of primary
$\alpha$-elements, can be understood in a natural way if clusters with high,
elongated orbits with different metallicities formed as a result of
interactions of two types of high-velocity clouds with the interstellar medium
of the Galactic disk: low-metallicity high-velocity clouds that formed from
"primordial" gas, and high-metallicity clouds with intermediate velocities that
formed in "Galactic fountains".


title:
Hardy-type inequalities for fractional powers of the Dunkl--Hermite
  operator

abstract:
  We prove Hardy-type inequalities for a fractional Dunkl--Hermite operator
which incidentally give Hardy inequalities for the fractional harmonic
oscillator as well. The idea is to use $h$-harmonic expansions to reduce the
problem in the Dunkl--Hermite context to the Laguerre setting. Then, we push
forward a technique based on a non-local ground representation, initially
developed by R. L. Frank, E. H. Lieb and R. Seiringer in the Euclidean setting,
to get a Hardy inequality for the fractional-type Laguerre operator. The
above-mentioned method is shown to be adaptable to an abstract setting,
whenever there is a "good" spectral theorem and an integral representation for
the fractional operators involved.


title:
The Brauer-Manin obstruction to the local-global principle for the
  embedding problem

abstract:
  We study an analogue of the Brauer-Manin obstruction to the local-global
principle for embedding problems over global fields. We will prove the
analogues of several fundamental structural results. In particular we show that
the (algebraic) Brauer-Manin obstruction is the only one to weak approximation
when the embedding problem has abelian kernel. As a part of our investigations
we also give a new, elegant description of the Tate duality pairing and prove a
new theorem on the cup product.


title:
The influence of temperature dynamics and dynamic finite ion Larmor
  radius effects on seeded high amplitude plasma blobs

abstract:
  Thermal effects on the perpendicular convection of seeded pressure blobs in
the scrape-off layer of magnetised fusion plasmas are investigated. Our
numerical study is based on a four field full-F gyrofluid model, which entails
the consistent description of high fluctuation amplitudes and dynamic finite
Larmor radius effects. We find that the maximal radial blob velocity increases
with the square root of the initial pressure perturbation and that a finite
Larmor radius contributes to highly compact blob structures that propagate in
the poloidal direction. An extensive parameter study reveals that a smooth
transition to this compact blob regime occurs when the finite Larmor radius
effect strength, defined by the ratio of the magnetic field aligned component
of the ion diamagnetic to the $\vec{E}\times\vec{B}$ vorticity, exceeds unity.
The maximal radial blob velocities agree excellently with the inertial velocity
scaling law over more than an order of magnitude. We show that the finite
Larmor radius effect strength affects the poloidal and total particle transport
and present an empirical scaling law for the poloidal and total blob
velocities. Distinctions to the blob behaviour in the isothermal limit with
constant finite Larmor radius effects are highlighted.


title:
Extreme abundance ratios in the polluted atmosphere of the cool white
  dwarf NLTT19868

abstract:
  We present an analysis of intermediate-dispersion spectra and photometric
data of the newly identified cool, polluted white dwarf NLTT19868. The spectra
obtained with X-shooter on the Very Large Telescope (VLT)-Melipal show strong
lines of calcium, and several lines of magnesium, aluminium and iron. We use
these spectra and the optical-to-near infrared spectral energy distribution to
constrain the atmospheric parameters of NLTT19868. Our analysis shows that
NLTT19868 is iron poor with respect to aluminium and calcium. A comparison with
other cool, polluted white dwarfs shows that the Fe to Ca abundance ratio
(Fe/Ca) varies by up to approximately two orders of magnitudes over a narrow
temperature range with NLTT19868 at one extremum in the Fe/Ca ratio and, in
contrast, NLTT888 at the other extremum. The sample shows evidence of extreme
diversity in the composition of the accreted material: In the case of NLTT888,
the inferred composition of the accreted matter is akin to iron-rich planetary
core composition, while in the case of NLTT19868 it is close to mantle or
bulk-Earth composition depleted by subsequent chemical separation at the bottom
of the convection zone.


title:
On the moments of roots of Laguerre-polynomials and the Marchenko-Pastur
  law

abstract:
  In this paper we compute the leading terms in the sum of the $k^{th}$ power
of the roots of $L_{p}^{(\alpha)}$, the Laguerre-polynomial of degree $p$ with
parameter $\alpha$. The connection between the Laguerre-polynomials and the
Marchenko-Pastur distribution is expressed by the fact, among others, that the
limiting distribution of the empirical distribution of the normalized roots of
the Laguerre-polynomials is given by the Marchenko-Pastur distribution. We give
a direct proof of this statement based on the recursion satisfied by the
Laguerre-polynomials. At the same time, our main result gives that the leading
term in $p$ and $(\alpha+p)$ of the sum of the $k^{th}$ power of the roots of
$L_{p}^{(\alpha)}$ coincides with the $k^{th}$ moment of the Marchenko-Pastur
law. We also mention the fact that the expectation of the characteristic
polynomial of a $XX^T$ type random covariance matrix, where $X$ is a $p\times
n$ random matrix with iid elements, is $\ell^{(n-p)}_p$, i.e. the monic version
of the $p^{th}$ Laguerre polynomial with parameter $n-p$.


title:
Effects of a dressed quark-gluon vertex in vector heavy-light mesons and
  theory average of B(c)* meson mass

abstract:
  We extend earlier investigations of heavy-light pseudoscalar mesons to the
vector case, using a simple model in the context of the
Dyson-Schwinger-Bethe-Salpeter approach. We investigate the effects of a
dressed-quark-gluon vertex in a systematic fashion and illustrate and attempt
to quantify corrections beyond the phenomenologically very useful and
successful rainbow-ladder truncation. In particular we investigate dressed
quark photon vertex in such a setup and make a prediction for the
experimentally as yet unknown mass of the B_c*, which we obtain at 6.334 GeV
well in line with predictions from other approaches. Furthermore, we combine a
comprehensive set of results from the theory literature. The theory average for
the mass of the B_c* meson is 6.336 +- 0.002 GeV.


title:
The Multivariate Generalised von Mises distribution: Inference and
  applications

abstract:
  Circular variables arise in a multitude of data-modelling contexts ranging
from robotics to the social sciences, but they have been largely overlooked by
the machine learning community. This paper partially redresses this imbalance
by extending some standard probabilistic modelling tools to the circular
domain. First we introduce a new multivariate distribution over circular
variables, called the multivariate Generalised von Mises (mGvM) distribution.
This distribution can be constructed by restricting and renormalising a general
multivariate Gaussian distribution to the unit hyper-torus. Previously proposed
multivariate circular distributions are shown to be special cases of this
construction. Second, we introduce a new probabilistic model for circular
regression, that is inspired by Gaussian Processes, and a method for
probabilistic principal component analysis with circular hidden variables.
These models can leverage standard modelling tools (e.g. covariance functions
and methods for automatic relevance determination). Third, we show that the
posterior distribution in these models is a mGvM distribution which enables
development of an efficient variational free-energy scheme for performing
approximate inference and approximate maximum-likelihood learning.


title:
Nonlinear Schr\"odinger equation from generalized exact uncertainty
  principle

abstract:
  Inspired by the generalized uncertainty principle (GUP), which adds
gravitational effects to the standard description of quantum uncertainty, we
extend the exact uncertainty principle (EUP) approach by Hall and Reginatto [J.
Phys. A: Math. Gen. (2002) 35 3289], and obtain a (quasi)nonlinear
Schr\"odinger equation. This quantum evolution equation of unusual form, enjoys
several desired properties like separation of non-interacting subsystems or
planewave solutions for free particles. Starting with the harmonic oscillator
example, we show that every solution of this equation respects the
gravitationally-induced minimal position uncertainty proportional to the Planck
length. Quite surprisingly, our result successfully merges the core of
classical physics with non-relativistic quantum mechanics in its extremal form.
We predict that the commonly accepted phenomenon, namely a modification of a
free-particle dispersion relation due to quantum gravity might not occur in
reality.


title:
Spectroscopic Indication for a Centi-parsec Supermassive Black Hole
  Binary in the Galactic Center of NGC 5548

abstract:
  As a natural consequence of cosmological hierarchical structure formation,
sub-parsec supermassive black hole binaries (SMBHBs) should be common in
galaxies but thus far have eluded spectroscopic identification. Based on four
decades of optical spectroscopic monitoring, we report that the nucleus of NGC
5548, a nearby Seyfert galaxy long suspected to have experienced a major merger
about one billion years ago, exhibits long-term variability with a period of 14
years in the optical continuum and broad Hbeta emission line. Remarkably, the
double-peaked profile of Hbeta shows systematic velocity changes with a similar
period. These pieces of observations plausibly indicate that a SMBHB resides in
the center of NGC 5548. The complex, secular variations in the line profiles
can be explained by orbital motion of a binary with equal mass and a semi-major
axis of 22 light-days (corresponding to 18 milli-parsec). At a distance of 75
Mpc, NGC 5548 is one of the nearest sub-parsec SMBHB candidates that offers an
ideal laboratory for gravitational wave detection.


title: Towards Rydberg quantum logic with trapped ions

abstract:
  We demonstrate the excitation of ions to the Rydberg state $22F$ by vacuum
ultraviolet radiation at a wavelength of $123\,\text{nm}$ combined with the
coherent manipulation of the optical qubit transition in $^{40}\text{Ca}^+$.
With a tightly focused beam at $729\,\text{nm}$ wavelength we coherently excite
a single ion from a linear string into the metastable $3D_{5/2}$ state before a
VUV pulse excites it to the Rydberg state. In combination with ion shuttling in
the trap, we extend this approach to the addressed excitation of multiple ions.
The coherent initialization as well as the addressed Rydberg excitation are key
prerequisites for more complex applications of Rydberg ions in quantum
simulation or quantum information processing.


title: Finite-time blowup for some nonlinear complex Ginzburg-Landau equations

abstract:
  In this article, we review finite-time blowup criteria for the family of
complex Ginzburg-Landau equations $u_t = e^{ i\theta } [\Delta u + |u|^\alpha
u] + \gamma u$ on ${\mathbb R}^N $, where $0 \le \theta \le \frac {\pi } {2}$,
$\alpha >0$ and $\gamma \in {\mathbb R} $. We study in particular the effect of
the parameters $\theta $ and $\gamma $, and the dependence of the blowup time
on these parameters.