title:
Generation of Spin Currents by Magnetic Field in $\mathcal{T}$- and
  $\mathcal{P}$-Broken Materials

abstract:
  Pure spin currents carry information in quantum spintronics and could play an
essential role in the next generation low-energy-consumption electronics. Here
we theoretically predict that the magnetic field can induce a quantum spin
current without a concomitant charge current in metals without time reversal
symmetry $\mathcal{T}$ and inversion symmetry $\mathcal{P}$ but respect the
combined $\mathcal{PT}$ symmetry. It is governed by the magnetic moment of the
Bloch states on the Fermi surface, and can be regarded as a spinful
generalization of the gyrotropic magnetic effect in $\mathcal{P}$-broken
metals. The effect is explicitly studied for a minimal model of an
antiferromagnetic Dirac semimetal, where the experimental signature is
proposed. We further propose candidate materials, including topological
antiferromagnetic Dirac semimetals, Weyl semimetals, and tenary Heusler
compounds.


title: All Your Cards Are Belong To Us: Understanding Online Carding Forums

abstract:
  Underground online forums are platforms that enable trades of illicit
services and stolen goods. Carding forums, in particular, are known for being
focused on trading financial information. However, little evidence exists about
the sellers that are present on carding forums, the precise types of products
they advertise, and the prices buyers pay. Existing literature mainly focuses
on the organisation and structure of the forums. Furthermore, studies on
carding forums are usually based on literature review, expert interviews, or
data from forums that have already been shut down. This paper provides
first-of-its-kind empirical evidence on active forums where stolen financial
data is traded. We monitored 5 out of 25 discovered forums, collected posts
from the forums over a three-month period, and analysed them quantitatively and
qualitatively. We focused our analyses on products, prices, seller prolificacy,
seller specialisation, and seller reputation.


title: Geometrothermodynamics for Black holes and de Sitter Space

abstract:
  In this report, a general method to extract thermodynamic quantities from
solutions of the Einstein equation is developed. In 1994, Wald established that
the entropy of a black hole could be identified as a Noether charge associated
with a Killing vector of a global space-time (pseudo-Riemann) manifold. We
reconstruct Wald's method using geometrical language, e.g$.$, via differential
forms defined on the local space-time (Minkowski) manifold. Concurrently, the
abstract thermodynamics are also reconstructed using geometrical terminology,
which is parallel to general relativity. The correspondence between the
thermodynamics and general relativity can be seen clearly by comparing the two
expressions. This comparison requires a modification of Wald's method.
  The new method is applied to Schwarzschild, Kerr, and Kerr--Newman black
holes and de Sitter space. The results are consistent with previous results
obtained using various independent methods. This strongly supports the validity
of the area theorem for black holes.


title: One qubit and one photon -- the simplest polaritonic heat engine

abstract:
  Hybrid quantum systems can often be described in terms of polaritons. These
are quasiparticles formed of superpositions of their constituents, with
relative weights depending on some control parameter in their interaction. In
many cases, these constituents are coupled to reservoirs at different
temperatures. This suggests a general approach to the realization of
polaritonic heat engines where a thermodynamic cycle is realized by tuning this
control parameter. Here we discuss what is arguably the simplest such engine, a
single qubit coupled to a single photon. We show that this system can extract
work from feeble thermal microwave fields. We also propose a quantum
measurement scheme of the work and evaluate its back-action on the operation of
the engine.


title:
Holographic intravital microscopy for 2-D and 3-D imaging intact
  circulating blood cells in microcapillaries of live mice

abstract:
  Intravital microscopy is an essential tool that reveals behaviours of live
cells under conditions close to natural physiological states. So far, although
various approaches for imaging cells in vivo have been proposed, most require
the use of labelling and also provide only qualitative imaging information.
Holographic imaging approach based on measuring the refractive index
distributions of cells, however, circumvent these problems and offer
quantitative and label-free imaging capability. Here, we demonstrate in vivo
two- and three-dimensional holographic imaging of circulating blood cells in
intact microcapillaries of live mice. The measured refractive index
distributions of blood cells provide morphological and biochemical properties
including three-dimensional cell shape, haemoglobin concentration, and
haemoglobin contents at the individual cell level. With the present method,
alterations in blood flow dynamics in live healthy and sepsis-model mouse were
also investigated.

categories: physics.bio-ph physics.med-ph physics.optics q-bio.QM


title: Scaling of random walk betweenness in networks

abstract:
  The betweenness centrality of graphs using random walk paths instead of
geodesics is studied. A scaling collapse with no adjustable parameters is
obtained as the graph size $N$ is varied; the scaling curve depends on the
graph model. A normalized random betweenness, that counts each walk passing
through a node only once, is also defined. It is argued to be more useful and
seen to have simpler scaling behavior. In particular, the probability for a
random walk on a preferential attachment graph to pass through the root node is
found to tend to unity as $N\rightarrow\infty.$


title: Less-forgetting Learning in Deep Neural Networks

abstract:
  A catastrophic forgetting problem makes deep neural networks forget the
previously learned information, when learning data collected in new
environments, such as by different sensors or in different light conditions.
This paper presents a new method for alleviating the catastrophic forgetting
problem. Unlike previous research, our method does not use any information from
the source domain. Surprisingly, our method is very effective to forget less of
the information in the source domain, and we show the effectiveness of our
method using several experiments. Furthermore, we observed that the forgetting
problem occurs between mini-batches when performing general training processes
using stochastic gradient descent methods, and this problem is one of the
factors that degrades generalization performance of the network. We also try to
solve this problem using the proposed method. Finally, we show our
less-forgetting learning method is also helpful to improve the performance of
deep neural networks in terms of recognition rates.


title: Spin and localization of relativistic fermions and uncertainty relations

abstract:
  We discuss relations between several relativistic spin observables and derive
a Lorentz-invariant characteristic of a reduced spin density matrix.A
relativistic position operator that satisfies all the properties of its
nonrelativistic analog does not exist. Instead we propose two
causality-preserving positive operator-valued measures (POVMs) that are based
on projections onto one-particle and antiparticle spaces, and on the normalized
energy density. They predict identical expectation values for position. The
variances differ by less than a quarter of the squared de Broglie wavelength
and coincide in the nonrelativistic limit. Since the resulting statistical
moment operators are not canonical conjugates of momentum, the Heisenberg
uncertainty relations need not hold. Indeed, the energy density POVM leads to a
lower uncertainty. We reformulate the standard equations of the spin dynamics
by explicitly considering the charge-independent acceleration, allowing a
consistent treatment of backreaction and inclusion of a weak gravitational
field.


title:
Probing strongly hybrid nuclear-electronic states in a model quantum
  ferromagnet

abstract:
  We present direct local-probe evidence for strongly hybridized
nuclear-electronic spin states of an Ising ferromagnet LiHoF$_4$ in a
transverse magnetic field. The nuclear-electronic states are addressed via a
magnetic resonance in the GHz frequency range using coplanar resonators and a
vector network analyzer. The magnetic resonance spectrum is successfully traced
over the entire field-temperature phase diagram, which is remarkably well
reproduced by mean-field calculations. Our method can be directly applied to a
broad class of materials containing rare-earth ions for probing the
substantially mixed nature of the nuclear and electronic moments.


title: Fluctuation sound absorption in quark matter

abstract:
  We investigate the sound absorption in quark matter due to the interaction of
the sound wave with the precritical fluctuations of the diquark-pair field
above $T_c$. The soft collective mode of the pair field is derived using the
time dependent Ginzburg-Landau functional with random Langevin forces. The
strong absorption near the phase transition line may be viewed as a
manifestation of the Mandelshtam-Leontovich slow relaxation time theory.


title:
Dynamics and Protecting of Entanglement in Two-Level Systems Interacting
  with a Dissipative Cavity: The Gardiner-Collett Approach

abstract:
  In this paper, we study the exact entanglement dynamics of two two-level
atoms in a dissipative cavity. We use the Gardiner-Collett Hamiltonian to model
the dissipative cavity, in which, we assume that the two atoms resonantly
interact with the cavity field and the cavity field itself interacts with the
surrounding medium. Then, with the help of the Fano's technique, we show that,
this system can be regarded as two atoms interacting with a heat bath. In such
a case, we find that, there exists a decoherence-free state that does not
evolve in time. At this time, there exists a so-called super-radiant state
which decays in time due to dissipation. At last, we use the quantum Zeno
effect to preserve the entanglement which already has been stored in the
system.


title:
Tensor Network alternating linear scheme for MIMO Volterra system
  identification

abstract:
  This article introduces two Tensor Network-based iterative algorithms for the
identification of high-order discrete-time nonlinear multiple-input
multiple-output (MIMO) Volterra systems. The system identification problem is
rewritten in terms of a Volterra tensor, which is never explicitly constructed,
thus avoiding the curse of dimensionality. It is shown how each iteration of
the two identification algorithms involves solving a linear system of low
computational complexity. The proposed algorithms are guaranteed to
monotonically converge and numerical stability is ensured through the use of
orthogonal matrix factorizations. The performance and accuracy of the two
identification algorithms are illustrated by numerical experiments, where
accurate degree-10 MIMO Volterra models are identified in about 1 second in
Matlab on a standard desktop pc.


abstract:
  New experimental results on bacterial growth inspire a novel top-down
approach to study cell metabolism, combining mass balance and proteomic
constraints to extend and complement Flux Balance Analysis. We introduce here
Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic
costs associated to growth are accounted for in an effective way through a
single additional genome-wide constraint. Its roots lie in the experimentally
observed pattern of proteome allocation for metabolic functions, allowing to
bridge regulation and metabolism in a transparent way under the principle of
growth-rate maximization. We provide a simple method to solve CAFBA efficiently
and propose an "ensemble averaging" procedure to account for unknown protein
costs. Applying this approach to modeling E. coli metabolism, we find that, as
the growth rate increases, CAFBA solutions cross over from respiratory,
growth-yield maximizing states (preferred at slow growth) to fermentative
states with carbon overflow (preferred at fast growth). In addition, CAFBA
allows for quantitatively accurate predictions on the rate of acetate excretion
and growth yield based on only 3 parameters determined by empirical growth
laws.

categories: q-bio.MN cond-mat.dis-nn physics.bio-ph q-bio.QM


title:
Oxygen, $\alpha$-element and iron abundance distributions in the inner
  part of the Galactic thin disc. II

abstract:
  We have derived the abundances of 36 chemical elements in one Cepheid star,
ASAS 181024--2049.6, located R$_{\rm G}= 2.53$ kpc from the Galactic center.
This star falls within a region of the inner thin disc poorly sampled in
Cepheids. Our spectral analysis shows that iron, magnesium, silicon, calcium
and titanium LTE abundances in that star support the presence of a plateau-like
abundance distribution in the thin disc within 5 kpc of the Galactic center, as
previously suggested by \cite{Maret15}. If confirmed, the flattening of the
abundance gradient within that region could be the result of a decrease in the
star formation rate due to dynamic effects, possibly from the central Galactic
bar.


title: Reduction of Classical Measurement Noise via Quantum-Dense Metrology

abstract:
  Quantum-dense metrology (QDM) constitutes a special case of quantum metrology
in which two orthogonal phase space projections of a signal are simultaneously
sensed beyond the shot noise limit. Previously it was shown that the additional
sensing channel that is provided by QDM contains information that can be used
to identify and to discard corrupted segments from the measurement data. Here,
we demonstrate a proof-of-principle experiment in which this information is
used for improving the sensitivity without discarding any measurement segments.
Our measurement reached sub-shot-noise performance although initially strong
classical noise polluted the data.


title:
Book crossing numbers of the complete graph and small local convex
  crossing numbers

abstract:
  A $ k $-page book drawing of a graph $ G $ is a drawing of $ G $ on $ k $
halfplanes with common boundary $ l $, a line, where the vertices are on $ l $
and the edges cannot cross $ l $. The $ k $-page book crossing number of the
graph $ G $, denoted by $ \nu_k(G) $, is the minimum number of edge-crossings
over all $ k $-page book drawings of $ G $. Let $G=K_n$ be the complete graph
on $n$ vertices. We improve the lower bounds on $ \nu_k(K_n) $ for all $ k\geq
14 $ and determine $ \nu_k(K_n) $ whenever $ 2 < n/k \leq 3 $. Our proofs rely
on bounding the number of edges in convex graphs with small local crossing
numbers. In particular, we determine the maximum number of edges that a convex
graph with local crossing number at most $ \ell $ can have for $ \ell\leq 4 $.


title: Reduced Spherical Convex Bodies

abstract:
  The aim of this paper is to present some properties of reduced spherical
convex bodies on the two-dimensional sphere $S^2$. The intersection of two
different non-opposite hemispheres is called a lune. By its thickness we mean
the distance of the centers of the two semicircles bounding it. The thickness
$\Delta (C)$ of $C$ is the minimum thickness of a lune containing $C$. We say
that a spherical convex body $R$ is reduced if $\Delta (Z) < \Delta (R)$ for
every spherical convex body $Z \subset R$ different from $R$. Our main theorem
permits to describe the shape of reduced bodies of thickness below
$\frac{\pi}{2}$. It implies a number of corollaries. In particular, we estimate
the diameter of reduced spherical bodies in terms of their thickness. Reduced
bodies of thickness at least $\frac{\pi}{2}$ have constant width. Spherical
convex bodies of constant width below $\frac{\pi}{2}$ are strictly convex.


title: Deep Learning with Differential Privacy

abstract:
  Machine learning techniques based on neural networks are achieving remarkable
results in a wide variety of domains. Often, the training of models requires
large, representative datasets, which may be crowdsourced and contain sensitive
information. The models should not expose private information in these
datasets. Addressing this goal, we develop new algorithmic techniques for
learning and a refined analysis of privacy costs within the framework of
differential privacy. Our implementation and experiments demonstrate that we
can train deep neural networks with non-convex objectives, under a modest
privacy budget, and at a manageable cost in software complexity, training
efficiency, and model quality.


title: Dynamical Memory Effects in Correlated Quantum Channels

abstract:
  Memory effects play a fundamental role in the study of the dynamics of open
quantum systems. There exist two conceptually distinct notions of memory
discussed for quantum channels in the literature. In quantum information theory
quantum channels with memory are characterised by the existence of correlations
between successive applications of the channel on a sequence of quantum
systems. In open quantum systems theory memory effects arise dynamically during
the time evolution of quantum systems, and define non-Markovian dynamics. Here
we relate and combine these two different concepts of memory. In particular, we
study the interplay between correlations between multiple uses of quantum
channels and non-Markovianity as non-divisibility of the $t$-parametrized
family of channels defining the dynamical map.


title: Testing the Monogamy Relations via Rank-2 Mixtures

abstract:
  We introduce two tangle-based four-party entanglement measures $t_1$ and
$t_2$, and two negativity-based measures $n_1$ and $n_2$, which are derived
from the monogamy relations. These measures are computed for three four-qubit
maximally entangled and W states explicitly. We also compute these measures for
the rank-$2$ mixture $\rho_4 = p \ket{\mbox{GHZ}_4} \bra{\mbox{GHZ}_4} + (1 -
p) \ket{\mbox{W}_4} \bra{\mbox{W}_4}$ by finding the corresponding optimal
decompositions. It turns out that $t_1 (\rho_4)$ is trivial and the
corresponding optimal decomposition is equal to the spectral decomposition.
Probably, this triviality is a sign of the fact that the corresponding monogamy
inequality is not sufficiently tight. We fail to compute $t_2 (\rho_4)$ due to
the difficulty for the calculation of the residual entanglement. The
negativity-based measures $n_1 (\rho_4)$ and $n_2 (\rho_4)$ are explicitly
computed and the corresponding optimal decompositions are also derived
explicitly.


title:
Missing Data Estimation in High-Dimensional Datasets: A Swarm
  Intelligence-Deep Neural Network Approach

abstract:
  In this paper, we examine the problem of missing data in high-dimensional
datasets by taking into consideration the Missing Completely at Random and
Missing at Random mechanisms, as well as theArbitrary missing pattern.
Additionally, this paper employs a methodology based on Deep Learning and Swarm
Intelligence algorithms in order to provide reliable estimates for missing
data. The deep learning technique is used to extract features from the input
data via an unsupervised learning approach by modeling the data distribution
based on the input. This deep learning technique is then used as part of the
objective function for the swarm intelligence technique in order to estimate
the missing data after a supervised fine-tuning phase by minimizing an error
function based on the interrelationship and correlation between features in the
dataset. The investigated methodology in this paper therefore has longer
running times, however, the promising potential outcomes justify the trade-off.
Also, basic knowledge of statistics is presumed.


title:
Sparse Graphical Representation based Discriminant Analysis for
  Heterogeneous Face Recognition

abstract:
  Face images captured in heterogeneous environments, e.g., sketches generated
by the artists or composite-generation software, photos taken by common cameras
and infrared images captured by corresponding infrared imaging devices, usually
subject to large texture (i.e., style) differences. This results in heavily
degraded performance of conventional face recognition methods in comparison
with the performance on images captured in homogeneous environments. In this
paper, we propose a novel sparse graphical representation based discriminant
analysis (SGR-DA) approach to address aforementioned face recognition in
heterogeneous scenarios. An adaptive sparse graphical representation scheme is
designed to represent heterogeneous face images, where a Markov networks model
is constructed to generate adaptive sparse vectors. To handle the complex
facial structure and further improve the discriminability, a spatial
partition-based discriminant analysis framework is presented to refine the
adaptive sparse vectors for face matching. We conducted experiments on six
commonly used heterogeneous face datasets and experimental results illustrate
that our proposed SGR-DA approach achieves superior performance in comparison
with state-of-the-art methods.


title: Representing Pattern Matching Algorithms by Polynomial-Size Automata

abstract:
  Pattern matching algorithms to find exact occurrences of a pattern
$S\in\Sigma^m$ in a text $T\in\Sigma^n$ have been analyzed extensively with
respect to asymptotic best, worst, and average case runtime. For more detailed
analyses, the number of text character accesses $X^{\mathcal{A},S}_n$ performed
by an algorithm $\mathcal{A}$ when searching a random text of length $n$ for a
fixed pattern $S$ has been considered. Constructing a state space and
corresponding transition rules (e.g. in a Markov chain) that reflect the
behavior of a pattern matching algorithm is a key step in existing analyses of
$X^{\mathcal{A},S}_n$ in both the asymptotic ($n\to\infty$) and the
non-asymptotic regime. The size of this state space is hence a crucial
parameter for such analyses. In this paper, we introduce a general methodology
to construct corresponding state spaces and demonstrate that it applies to a
wide range of algorithms, including Boyer-Moore (BM), Boyer-Moore-Horspool
(BMH), Backward Oracle Matching (BOM), and Backward (Non-Deterministic) DAWG
Matching (B(N)DM). In all cases except BOM, our method leads to state spaces of
size $O(m^3)$ for pattern length $m$, a result that has previously only been
obtained for BMH. In all other cases, only state spaces with size exponential
in $m$ had been reported. Our results immediately imply an algorithm to compute
the distribution of $X^{\mathcal{A},S}_n$ for fixed $S$, fixed $n$, and
$\mathcal{A}\in\{\text{BM},\text{BMH},\text{B(N)DM}\}$ in polynomial time for a
very general class of random text models.


title:
TensiStrength: Stress and relaxation magnitude detection for social
  media texts

abstract:
  Computer systems need to be able to react to stress in order to perform
optimally on some tasks. This article describes TensiStrength, a system to
detect the strength of stress and relaxation expressed in social media text
messages. TensiStrength uses a lexical approach and a set of rules to detect
direct and indirect expressions of stress or relaxation, particularly in the
context of transportation. It is slightly more effective than a comparable
sentiment analysis program, although their similar performances occur despite
differences on almost half of the tweets gathered. The effectiveness of
TensiStrength depends on the nature of the tweets classified, with tweets that
are rich in stress-related terms being particularly problematic. Although
generic machine learning methods can give better performance than TensiStrength
overall, they exploit topic-related terms in a way that may be undesirable in
practical applications and that may not work as well in more focused contexts.
In conclusion, TensiStrength and generic machine learning approaches work well
enough to be practical choices for intelligent applications that need to take
advantage of stress information, and the decision about which to use depends on
the nature of the texts analysed and the purpose of the task.


title:
Synthetic Dimensions with Magnetic Fields and Local Interactions in
  Photonic Lattices

abstract:
  We discuss how one can realize a photonic device that combines synthetic
dimensions and synthetic magnetic fields with spatially local interactions.
Using an array of ring cavities, the angular coordinate around each cavity
spans the synthetic dimension. The synthetic magnetic field arises as the
intercavity photon hopping is associated with a change of angular momentum.
Photon-photon interactions are local in the periodic angular coordinate around
each cavity. Experimentally observable consequences of the synthetic magnetic
field and of the local interactions are pointed out.


title: A Fully Abstract Semantics for Value-passing CCS for Trees

abstract:
  This paper provides a fully abstract semantics for value-passing CCS for
trees (VCCTS). The operational semantics is given both in terms of a reduction
semantics and in terms of a labelled transition semantics. The labelled
transition semantics is non-sequential, allowing more than one action occurring
simultaneously. We develop the theory of behavioral equivalence by introducing
both weak barbed congruence and weak bisimilarity. In particular, we show that
weak barbed congruence coincides with weak bisimilarity on image-finite
processes. This is the first such result for a concurrent model with tree
structures. Distributed systems can be naturally modeled by means of this
graph-based system, and some examples are given to illustrate this.


title:
HD 179821 (V1427 Aql, IRAS 19114+0002) -- A Massive Post-Red Supergiant
  Star?

abstract:
  We have derived elemental abundances of a remarkable star, HD 179821, with
unusual composition (e.g. [Na/Fe]=1.0$\pm$0.2 dex) and extra-ordinary spectral
characteristics. Its metallicity at [Fe/H]=0.4 dex places it among the most
metal-rich stars yet analyzed. The abundance analysis of this luminous star is
based on high resolution and high quality (S/N$\approx$120--420) optical
echelle spectra from McDonald Observatory and Special Astronomy Observatory.
The data includes five years of observations over twenty-one epochs. Standard
1D {\sc LTE} analysis provides a fresh determination of the atmospheric
parameters over all epochs: \Teff = 7350$\pm$200 \kelvin, \logg = +0.6$\pm$0.3,
and a microturbulent velocity $\xi =$ 6.6$\pm$1.6 km s$^{\rm -1}$ and [Fe/H] =
0.4$\pm$0.2, and a carbon abundance [C/Fe]= $-$0.19$\pm$0.30. We find oxygen
abundance [O/Fe]= $-$0.25$\pm$0.28 and an enhancement of 0.9 dex in N. A
supersonic macroturbulent velocity of 22.0 $\pm$ 2.0 km s$^{\rm -1}$ is
determined from both strong and weak Fe\,{\sc i} and Fe\,{\sc ii} lines.
Elemental abundances are obtained for 22 elements. HD 179821 is not enriched in
s-process products. Eu is overabundant relative to the anticipated [X/Fe]
$\approx$ 0.0. Some peculiarities of its optical spectrum (e.g. variability in
the spectral line shapes) is noticed. This includes the line profile variations
for H$\alpha$ line. Based on its estimated luminosity, effective temperature
and surface gravity, HD 179821 is a massive star evolving to become a red
supergiant and finally a Type II supernova.


title:
Nuclear recoil corrections to the Lamb shift of hydrogen and light
  hydrogen-like ions

abstract:
  Accurate calculations of the nuclear recoil effect to the Lamb shift of
hydrogen-like atoms are presented. Numerical results are reported for the $ns$
states with $n \leq 5$ and for the $2p_{1/2}$ and $2p_{3/2}$ states. The
calculations are performed to the first order in the electron-nucleus mass
ratio and to all orders in the nuclear binding strength parameter $Z\alpha$
(where $Z$ is the nuclear charge number and $\alpha$ is the fine structure
constant). The obtained results provide accurate predictions for the
higher-order remainder beyond the known $Z\alpha$-expansion terms. In the case
of hydrogen, the remainder was found to be much larger than anticipated. This
result resolves the previously reported disagreement between the numerical
all-order and the analytical $Z\alpha$-expansion approaches for the nuclear
recoil effect in the hydrogen Lamb shift.


title: Global model structures for $*$-modules

abstract:
  We extend Schwede's work on the unstable global homotopy theory of orthogonal
spaces and $\mathcal{L}$-spaces to the category of $*$-modules (i.e., unstable
$S$-modules). We prove a theorem which transports model structures and their
properties from $\mathcal{L}$-spaces to $*$-modules and show that the resulting
global model structure for $*$-modules is monoidally Quillen equivalent to that
of orthogonal spaces. As a consequence, there are induced Quillen equivalences
between the associated model categories of monoids, which identify equivalent
models for the global homotopy theory of $A_\infty$-spaces.


title: Design of a high-performance GEMM-like Tensor-Tensor Multiplication

abstract:
  We present "GEMM-like Tensor-Tensor multiplication" (GETT), a novel approach
to tensor contractions that mirrors the design of a high-performance general
matrix-matrix multiplication (GEMM). The critical insight behind GETT is the
identification of three index sets, involved in the tensor contraction, which
enable us to systematically reduce an arbitrary tensor contraction to loops
around a highly tuned "macro-kernel". This macro-kernel operates on suitably
prepared ("packed") sub-tensors that reside in a specified level of the cache
hierarchy. In contrast to previous approaches to tensor contractions, GETT
exhibits desirable features such as unit-stride memory accesses,
cache-awareness, as well as full vectorization, without requiring auxiliary
memory. To compare our technique with other modern tensor contractions, we
integrate GETT alongside the so called Transpose-Transpose-GEMM-Transpose and
Loops-over-GEMM approaches into an open source "Tensor Contraction Code
Generator" (TCCG). The performance results for a wide range of tensor
contractions suggest that GETT has the potential of becoming the method of
choice: While GETT exhibits excellent performance across the board, its
effectiveness for bandwidth-bound tensor contractions is especially impressive,
outperforming existing approaches by up to $12.4\times$. More precisely, GETT
achieves speedups of up to $1.41\times$ over an equivalent-sized GEMM for
bandwidth-bound tensor contractions while attaining up to $91.3\%$ of peak
floating-point performance for compute-bound tensor contractions.


title: Efficient and Consistent Robust Time Series Analysis

abstract:
  We study the problem of robust time series analysis under the standard
auto-regressive (AR) time series model in the presence of arbitrary outliers.
We devise an efficient hard thresholding based algorithm which can obtain a
consistent estimate of the optimal AR model despite a large fraction of the
time series points being corrupted. Our algorithm alternately estimates the
corrupted set of points and the model parameters, and is inspired by recent
advances in robust regression and hard-thresholding methods. However, a direct
application of existing techniques is hindered by a critical difference in the
time-series domain: each point is correlated with all previous points rendering
existing tools inapplicable directly. We show how to overcome this hurdle using
novel proof techniques. Using our techniques, we are also able to provide the
first efficient and provably consistent estimator for the robust regression
problem where a standard linear observation model with white additive noise is
corrupted arbitrarily. We illustrate our methods on synthetic datasets and show
that our methods indeed are able to consistently recover the optimal parameters
despite a large fraction of points being corrupted.


title: HERA Mock Observations: Looking for Closure HERA Memorandum Number 13

abstract:
  We investigate the use of closure phase as a method to detect the HI 21cm
signal from the neutral IGM during cosmic reionzation. Closure quantities have
the unique advantage of being independent of antenna-based calibration terms.
We employ realistic, large area sky models from Sims et al. (2016). These
include an estimate of the HI 21cm signal generated using 21cm FAST, plus
continuum models of both the diffuse Galactic synchrotron emission and the
extragalactic point sources. We employ the CASA simulator and adopt the
Dillon-Parsons HERA configuration to generate a uv measurement set. We then use
AIPS to calculate the closure phases as a function of frequency ('closure
spectra'), and python scripts for subsequent analysis. We find that the closure
spectra for the HI signal show dramatic structure in frequency, and based on
thermal noise alone, the redundant HERA-331 array should detect these
fluctuations easily. Comparatively, the frequency structure in the continuum
closure spectra is much smoother than that seen in the HI closure spectra.
Unfortunately, when the line and continuum signals are combined, the continuum
dominates the visibilities at the level of 10^3 to 10^4, and the line signal is
lost. We have investigated fitting and removing smooth curves in frequency to
the line plus continuum closure spectra, and find that the continuum itself
shows enough structure in frequency in the closure spectra to preclude
separation of the continuum and line based on such a process. We have also
considered the subtraction of the continuum from the visibilities using a sky
model, prior to calculation of the closure spectra. TRUNCATED.


title: LSTM-based Encoder-Decoder for Multi-sensor Anomaly Detection

abstract:
  Mechanical devices such as engines, vehicles, aircrafts, etc., are typically
instrumented with numerous sensors to capture the behavior and health of the
machine. However, there are often external factors or variables which are not
captured by sensors leading to time-series which are inherently unpredictable.
For instance, manual controls and/or unmonitored environmental conditions or
load may lead to inherently unpredictable time-series. Detecting anomalies in
such scenarios becomes challenging using standard approaches based on
mathematical models that rely on stationarity, or prediction models that
utilize prediction errors to detect anomalies. We propose a Long Short Term
Memory Networks based Encoder-Decoder scheme for Anomaly Detection (EncDec-AD)
that learns to reconstruct 'normal' time-series behavior, and thereafter uses
reconstruction error to detect anomalies. We experiment with three publicly
available quasi predictable time-series datasets: power demand, space shuttle,
and ECG, and two real-world engine datasets with both predictive and
unpredictable behavior. We show that EncDec-AD is robust and can detect
anomalies from predictable, unpredictable, periodic, aperiodic, and
quasi-periodic time-series. Further, we show that EncDec-AD is able to detect
anomalies from short time-series (length as small as 30) as well as long
time-series (length as large as 500).


title: A non-standard analysis of a cultural icon: The case of Paul Halmos

abstract:
  We examine Paul Halmos' comments on category theory, Dedekind cuts, devil
worship, logic, and Robinson's infinitesimals. Halmos' scepticism about
category theory derives from his philosophical position of naive set-theoretic
realism. In the words of an MAA biography, Halmos thought that mathematics is
"certainty" and "architecture" yet 20th century logic teaches us is that
mathematics is full of uncertainty or more precisely incompleteness. If the
term architecture meant to imply that mathematics is one great solid castle,
then modern logic tends to teach us the opposite lession, namely that the
castle is floating in midair. Halmos' realism tends to color his judgment of
purely scientific aspects of logic and the way it is practiced and applied. He
often expressed distaste for nonstandard models, and made a sustained effort to
eliminate first-order logic, the logicians' concept of interpretation, and the
syntactic vs semantic distinction. He felt that these were vague, and sought to
replace them all by his polyadic algebra. Halmos claimed that Robinson's
framework is "unnecessary" but Henson and Keisler argue that Robinson's
framework allows one to dig deeper into set-theoretic resources than is common
in Archimedean mathematics. This can potentially prove theorems not accessible
by standard methods, undermining Halmos' criticisms.
  Keywords: Archimedean axiom; bridge between discrete and continuous
mathematics; hyperreals; incomparable quantities; indispensability; infinity;
mathematical realism; Robinson.


title:
On the Control of Energy Storage Systems for Electric Vehicles Fast
  Charging in Service Areas

abstract:
  This paper presents a real time control strategy for energy storage systems
integration in electric vehicles fast charging applications combined with
generation from intermittent renewable energy sources. A two steps approach
taking advantage of the model predictive control methodology is designed on
purpose to optimally allocate the reference charging power while managing the
priority among the plugged vehicles and then control the storage for
efficiently sustaining the charging process. Two different use cases are
considered: in the former the charging area is disconnected from the grid, so
that the objective is to minimize the deviation of electric vehicles charging
power from the nominal value; in the latter the focus is on the point of
connection to the grid and the need of mitigating the related power flow. In
both cases the fundamental requirement for feasible control system operation is
to guarantee stability of the storage's state of charge over the time.
Simulation results are provided and discussed in detail, showing the
effectiveness of the proposed approach.


title: Choquard equations under confining external potentials

abstract:
  We consider the nonlinear Choquard equation $$ -\Delta u+V u=(I_\alpha \ast
\vert u\vert ^p)\vert u\vert ^{p-2}u \qquad \text{ in } \mathbb{R}^N $$ where
$N\geq 1$, $I_\alpha$ is the Riesz potential integral operator of order $\alpha
\in (0, N)$ and $p > 1$. If the potential $ V \in C (\mathbb{R}^N; [0,+\infty))
$ satisfies the confining condition $$ \liminf\limits_{\vert x\vert \to
+\infty}\frac{V(x)}{1+\vert x\vert ^{\frac{N+\alpha}{p}-N}}=+\infty, $$ and
$\frac{1}{p} > \frac{N - 2}{N + \alpha}$, we show the existence of a
groundstate, of an infinite sequence of solutions of unbounded energy and, when
$p \ge 2$ the existence of least energy nodal solution. The constructions are
based on suitable weighted compact embedding theorems. The growth assumption is
sharp in view of a Poho\v{z}aev identity that we establish.


title: Inhomogeneous molecular ring around the B[e] supergiant LHA 120-S 73

abstract:
  We aim to improve our knowledge on the structure and dynamics of the
circumstellar disk of the LMC B[e] supergiant LHA 120-S 73. High-resolution
optical and near-IR spectroscopic data were obtained over a period of 16 and 7
years, respectively. The spectra cover the diagnostic emission lines from
[CaII] and [OI], as well as the CO bands. These features trace the disk at
different distances from the star. We analyzed the kinematics of the individual
emission regions by modeling their emission profiles. A low-resolution
mid-infrared spectrum was obtained as well, which provides information on the
composition of the dusty disk. All diagnostic emission features display
double-peaked line profiles, which we interpret as due to Keplerian rotation.
We find that LHA 120-S 73 is surrounded by at least four individual rings of
material with alternating densities (or by a disk with strongly non-monotonic
radial density distribution). Moreover, we find that the molecular ring must
have gaps or at least strong density inhomogeneities, or in other words, a
clumpy structure. The mid-infrared spectrum displays features of oxygen- and
carbon-rich grain species, which indicates a long-lived, stable dusty disk. We
cannot confirm the previously reported high value for the stellar rotation
velocity. The line profile of HeI 5876 A is strongly variable in both width and
shape and resembles of those seen in non-radially pulsating stars. A proper
determination of the real underlying stellar rotation velocity is hence not
possible. The existence of multiple stable and clumpy rings of alternating
density recalls ring structures around planets. Although there is currently
insufficient observational evidence, it is tempting to propose a scenario with
one (or more) minor bodies or planets revolving around LHA 120-S 73 and
stabilizing the ring system, in analogy to the shepherd moons in planetary
systems.


title:
Equidistribution non-archim\'edienne et actions de groupes sur les
  arbres

abstract:
  Nous donnons des r\'esultats d'\'equidistribution d'\'el\'ements de corps de
fonctions sur des corps finis, et d'irrationnels quadratiques sur ces corps,
dans leurs corps locaux compl\'et\'es. Nous d\'eduisons ces r\'esultats de
th\'eor\`emes d'\'equidistribution de perpendiculaires communes dans des
quotients d'arbres par des r\'eseaux de leur groupe d'automorphismes,
d\'emontr\'es \`a l'aide de propri\'et\'es ergodiques du flot g\'eod\'esique
discret.
  Non-Archimedean equidistribution and group actions on trees. We give
equidistribution results of elements of function fields over finite fields, and
of quadratic irrationals over these fields, in their completed local fields. We
deduce these results from equidistribution theorems of common perpendiculars in
quotients of trees by lattices in their automorphism groups, proved by using
ergodic properties of the discrete geodesic flow.


title: Sharp constant for Poincar\'e-type inequalities in the hyperbolic space

abstract:
  In this note, we establish a Poincar\'e-type inequality on the hyperbolic
space $\mathbb H^n$, namely \[ \|u\|_{p} \leqslant C(n,m,p) \|\nabla^m_g
u\|_{p} \] for any $u \in W^{m,p}(\mathbb H^n)$. We prove that the sharp
constant $C(n,m,p)$ for the above inequality is \[ C(n,m,p) = \begin{cases}
\left( p p'/(n-1)^2 \right)^{m/2}&\mbox{if $m$ is even},\\ (p/(n-1))\left( p
p'/(n-1)^2\right)^{(m-1)/2} &\mbox{if $m$ is odd}, \end{cases} \] with $p' =
p/(p-1)$ and this sharp constant is never achieved in $W^{m,p}(\mathbb H^n)$.
Our proofs rely on the symmetrization method extended to hyperbolic spaces.


title: Solute-solute interactions in intermetallic compounds

abstract:
  Two types of solute-solute interactions are investigated in this work.
Quadrupole interactions caused by nearby Ag-solute atoms were measured at
nuclei of 111In/Cd solute probe atoms in the binary compound GdAl2 using the
method of perturbed angular correlation of gamma rays (PAC). Locations of
In-probes and Ag-solutes on both Gd- and Al-sublattices were identified by
comparing site fractions in Gd-poor and Gd-rich GdAl2(Ag) samples. Interaction
enthalpies between solute-atom pairs were determined from temperature
dependences of observed site fractions. Repulsive interactions were observed
for close-neighbor complexes In/Gd/+Ag/Gd/ and In/Gd/+Ag/Al/ pairs, whereas a
slightly attractive interaction was observed for In/Al/+Ag/Al/. Interaction
enthalpies were all in the range +/- 0.15 eV. Temperature dependences of site
fractions of In-probes on locally defect-free Gd- and Al-sites yields a
transfer enthalpy that was found to be 0.343 eV in a previous study of undoped
GdAl2. The corresponding values in GdAl2(Ag) samples are much smaller. This is
attributed to competition of In- and Ag-solutes to occupy sites of the same
sublattice. While the difference in site-enthalpies of In-solutes on Gd- and
Al-sites is temperature independent, it is proposed that the transfer of
Ag-solutes from Gd- to Al-sites leads to a large temperature dependence of
degeneracies of levels available to In-solutes, resulting in an effective
transfer enthalpy that is much smaller than the difference in site-enthalpies.


title:
Newton-Euler, Lagrange and Kirchhoff formulations of rigid body
  dynamics: a unified approach

abstract:
  A unified formulation of rigid body dynamics based on Gauss principle is
proposed. The Lagrange, Kirchhoff and Newton-Euler equations are seen to arise
from different choices of the quasicoordinates in the velocity space. The
group-theoretical aspects of the method are discussed.


title: Cluster Decay of the High-lying excited states in $^{14}$C

abstract:
  A cluster-transfer experiment of
$^9\rm{Be}(^9\rm{Be},^{14}\rm{C}\rightarrow\alpha+^{10}\rm{Be})\alpha$ at an
incident energy of 45 MeV was carried out in order to investigate the molecular
structure in high-lying resonant states in $^{14}$C. This reaction is of
extremely large $Q$-value, making it an excellent case to select the reaction
mechanism and the final states in outgoing nuclei. The high-lying resonances in
$^{14}$C are reconstructed for three sets of well discriminated final states in
$^{10}$Be. The results confirm the previous decay measurements with clearly
improved decay-channel selections and show also a new state at 23.5(1) MeV. The
resonant states at 22.4(3) and 24.0(3) MeV decay primarily into the typical
molecular states at about 6 MeV in $^{10}$Be, indicating a well developed
cluster structure in these high-lying states in $^{14}$C. Further measurements
of more states of this kind are suggested.


title:
Saturation magnetization and band gap tuning in BiFeO$_3$ nanoparticles
  via co-substitution of Gd and Mn

abstract:
  In this investigation, Gd and Mn co-doped
Bi$_{0.85}$Gd$_{0.15}$Fe$_{1-x}$Mn$_x$O$_3$ (x=0.0-0.15) nanoparticles have
been prepared to report the influence of co-substitution on their structural,
optical, magnetic and electrical properties. Due to simultaneous substitution
of Gd and Mn in BiFeO$_3$, the crystal structure has been modified from
rhombohedral (R3c) to orthorhombic (Pn21a) and the Fe-O-Fe bond angle and Fe-O
bond length have been changed. For Mn doping up to 10 % in
Bi$_{0.85}$Gd$_{0.15}$Fe$_{1-x}$Mn$_x$O$_3$ nanoparticles, the saturation
magnetization (Ms) has been enhanced significantly, however, for a further
increase of doping up to 15 %, the Ms has started to reduce again. The
co-substitution of Gd and Mn in BiFeO$_3$ nanoparticles also demonstrates a
strong reduction in the optical band gap energy and electrical resistivity
compared to that of undoped BiFeO$_3$.


title: Parton-shower Effects in Vector-Boson-Fusion Processes

abstract:
  We investigate the effects of combining next-to-leading order QCD results
with parton-shower effects in $W^+W^-jj$ production via vector-boson fusion
including leptonic decays. Using the Herwig 7 framework interfaced to VBFNLO 3,
we compare the predictions obtained from the angular-ordered and dipole-based
parton shower algorithms combined with subtractive, MC@NLO-type, and
multiplicative, Powheg-type, matching. A consistent treatment of
renormalisation and factorisation scale variations in the hard process and the
parton shower allows to assign more reliable theory uncertainty predictions to
key distributions like the central rapidity gap.


title: Trapping of solute atoms at grain boundaries in GdNi2

abstract:
  Lattice locations of 111In impurity probe atoms in intermetallic GdNi2 were
studied as a function of alloy composition and temperature using perturbed
angular correlation spectroscopy (PAC). Three nuclear quadrupole interaction
signals were detected and their equilibrium site fractions were measured up to
700 oC. Two signals have well-defined electric field gradients (EFGs) and are
attributed to In-probes on Gd- and Ni-sites in a well-ordered lattice. A third,
inhomogeneously broadened signal was observed at low temperature. This is
attributed to trapping, or segregation, of In-probes to lattice sinks such as
grain boundaries (GB) that have a large multiplicity of local environments and
EFGs. Changes in site fractions were reversible above 300oC. Measurements were
made on a pair of samples that were richer and poorer in Gd. Remarkably, the
GB-site was populated only in the more Gd-rich sample. This is explained by the
hypothesis that excess Gd segregates to the grain boundaries and provides a
lower enthalpy environment for In-probe atoms. Observations are discussed in
relation to a three-level quantum system. Enthalpy differences between levels
were determined from measurements of temperature dependences of ratios of site
fractions. The enthalpy of transfer of In-probes from the Gd- to Ni-sublattice
was found to be much smaller in the Gd-rich sample. This is attributed to a
large temperature-dependence in the degeneracies of levels available to
In-solutes in the phase, leading to an effective transfer enthalpy that differs
greatly from the difference in site-enthalpies. A possible scenario is
discussed. Different segregation enthalpies were measured for In-solute
transferring from GB sites to Gd- and Ni-sites, whereas only an average value
can be determined through macroscopic measurements.


title:
The violent white dwarf merger scenario for the progenitors of type Ia
  supernovae

abstract:
  Recent observations suggest that some type Ia supernovae (SNe Ia) originate
from the merging of two carbon-oxygen white dwarfs (CO WDs). Meanwhile, recent
hydrodynamical simulations have indicated that the accretion-induced collapse
may be avoided under certain conditions when double WDs merge violently.
However, the properties of SNe Ia from this violent merger scenario are highly
dependent on a particular mass-accretion stage, the so-called WD + He subgiant
channel, during which the primary WD is able to increase its mass by accreting
He-rich material from a He subgiant before the systems evolves into a double WD
system. In this article, we aim to study this particular evolutionary stage
systematically and give the properties of violent WD mergers. By employing the
Eggleton stellar evolution code, we followed a large number of binary
calculations and obtained the regions in parameter space for producing violent
mergers based on the WD + He subgiant channel. According to these simulations,
we found that the primary WDs can increase their mass by ~0.10-0.45 Msun during
the mass-accretion stage. We then conducted a series of binary population
synthesis calculations and found that the Galactic SN Ia birthrate from this
channel is about 0.01-0.4*10-3 yr-1. This suggests that the violent WD mergers
from this channel may only contribute to ~0.3%-10% of all SNe Ia in our Galaxy.
The delay times of violent WD mergers from this channel are >1.7 Gyr,
contributing to the SNe Ia in old populations. We also found that the WD + He
subgiant channel is the dominent way for producing violent WD mergers that may
be able to eventually explode as SNe Ia.


title: On entropy production of repeated quantum measurements I. General theory

abstract:
  We study entropy production (EP) in processes involving repeated quantum
measurements of finite quantum systems. Adopting a dynamical system approach,
we develop a thermodynamic formalism for the EP and study fine aspects of
irreversibility related to the hypothesis testing of the arrow of time. Under a
suitable chaoticity assumption, we establish a Large Deviation Principle and a
Fluctuation Theorem for the EP.

categories: math-ph math.DS math.MP math.PR quant-ph


title:
Alternative PV Bus Modelling with the Holomorphic Embedding Load Flow
  Method

abstract:
  The Holomorphic Embedding Load Flow Method (HELM) has been suggested as an
alternative approach to solve load flow problems. However, the current
literature does not provide any HELM models that can accurately handle general
power networks containing PV and PQ buses of realistic sizes. The original HELM
paper dealt only with PQ buses, while a second paper showed how to include PV
buses but suffered from serious accuracy problems. This paper fills this gap by
providing several models capable of solving general networks, with
computational results for the standard IEEE test cases provided for comparison.
In addition this paper also presents a new derivation of the theory behind the
method and investigates some of the claims made in the original HELM paper.


title:
Generalized concurrence measure for faithful quantification of
  multiparticle pure state entanglement using Lagrange's identity and wedge
  product

abstract:
  Concurrence, introduced by Hill and Wootters [Phys. Rev. Lett. 78, 5022
(1997)], provides an important measure of entanglement for a general pair of
qubits that is faithful: strictly positive for entangled states and vanishing
for all separable states. Such a measure captures the entire content of
entanglement, providing necessary and sufficient conditions for separability.
We present an extension of concurrence to multiparticle pure states in
arbitrary dimensions by a new framework using the Lagrange's identity and wedge
product representation of separability conditions, which coincides with the
"I-concurrence" of Rungta et al. [Phys. Rev. A 64, 042315 (2001)] who proposed
by extending Wootters's spin-flip operator to a so-called universal inverter
superoperator. Our framework exposes an inherent geometry of entanglement, and
may be useful for the further extensions to mixed and continuous variable
states.


title:
Pedestrian dynamics in single-file movement of crowd with different age
  compositions

abstract:
  An aging population is bringing new challenges to the management of escape
routes and facility design in many countries. This paper investigates
pedestrian movement properties of crowd with different age compositions. Three
pedestrian groups are considered: young student group, old people group and
mixed group. It is found that traffic jams occur more frequently in mixed group
due to the great differences of mobilities and self-adaptive abilities among
pedestrians. The jams propagate backward with a velocity 0.4 m/s for global
density around 1.75 m-1 and 0.3 m/s for higher than 2.3 m-1. The fundamental
diagrams of the three groups are obviously different from each other and cannot
be unified into one diagram by direct non-dimensionalization. Unlike previous
studies, three linear regimes in mixed group but only two regimes in young
student group are observed in the headway-velocity relation, which is also
verified in the fundamental diagram. Different ages and mobilities of
pedestrians in a crowd cause the heterogeneity of system and influence the
properties of pedestrian dynamics significantly. It indicates that the density
is not the only factor leading to jams in pedestrian traffic. The composition
of crowd has to be considered in understanding pedestrian dynamics and facility
design.


title:
Numerical investigation of the solutions of Schrodinger equation with
  exponential cubic B-spline finite element method

abstract:
  In this paper, we investigate the numerical solutions of the cubic nonlinear
Schrodinger equation via the exponential B-spline collocation method.
Crank-Nicolson formulas are used for time discretization of the target
equation. A linearization technique is also employed for the numerical purpose.
Four numerical examples related to single soliton, collision of two solitons
that move in opposite directions, the birht of standing and mobile solitons and
bound state solution are considered as the test problems. The accuracy and the
efficiency of the purposed method are measured by max error norm and conserved
constants. The obtained results are compared with the possible analytical
values and those in some earlier studies.


title:
SentiBubbles: Topic Modeling and Sentiment Visualization of
  Entity-centric Tweets

abstract:
  Social Media users tend to mention entities when reacting to news events. The
main purpose of this work is to create entity-centric aggregations of tweets on
a daily basis. By applying topic modeling and sentiment analysis, we create
data visualization insights about current events and people reactions to those
events from an entity-centric perspective.


title: On the classical Schr\"odinger equation

abstract:
  In this paper, the classical Schr\"odinger equation, which allows the study
of classical dynamics in terms of wave functions, is analyzed theoretically and
numerically. First, departing from classical (Newtonian) mechanics, and
assuming an additional single-valued condition for the Hamilton's principal
function, the classical Schr\"odinger equation is obtained. This additional
assumption implies inherent non-classical features on the description of the
dynamics obtained from the classical Schr\"odinger equation: the trajectories
do not cross in the configuration space. Second, departing from Bohmian
mechanics and invoking the quantum-to-classical transition, the classical
Schr\"odinger equation is obtained in a natural way for the center of mass of a
quantum system with a large number of identical particles. This quantum
development imposes the condition of dealing with a narrow wave packet, which
implicitly avoids the non-classical features mentioned above. We illustrate all
the above points with numerical simulations of the classical and quantum
Schr\"odinger equations for different systems.


title:
Size dependent magnetic and electrical properties of Ba-doped
  nanocrystalline BiFeO$_3$

abstract:
  Improvement in magnetic and electrical properties of multiferroic BiFeO$_3$
in conjunction with their dependence on particle size is crucial due to its
potential applications in multifunctional miniaturized devices. In this
investigation, we report a study on particle size dependent structural,
magnetic and electrical properties of sol-gel derived
Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles of different sizes ranging from
$\sim$ 12 to 49 nm. The substitution of Bi by Ba significantly suppresses
oxygen vacancies, reduces leakage current density and Fe$^{2+}$ state. An
improvement in both magnetic and electrical properties is observed for 10 %
Ba-doped BiFeO$_3$ nanoparticles compared to its undoped counterpart. The
saturation magnetization of Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles increase
with reducing particle size in contrast with a decreasing trend of
ferroelectric polarization. Moreover, a first order metamagnetic transition is
noticed for $\sim$ 49 nm Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles which
disappeared with decreasing particle size. The observed strong size dependent
multiferroic properties are attributed to the complex interaction between
vacancy induced crystallographic defects, multiple valence states of Fe,
uncompensated surface spins, crystallographic distortion and suppression of
spiral spin cycloid of BiFeO$_3$.


title:
Properties of groundstates of nonlinear Schr\"odinger equations under a
  weak constant magnetic field

abstract:
  We study the qualitative properties of groundstates of the time-independent
magnetic semilinear Schr\"odinger equation \[ - (\nabla + i A)^2 u + u =
|u|^{p-2} u, \qquad \text{ in } \mathbb{R}^N, \] where the magnetic potential
$A$ induces a constant magnetic field. When the latter magnetic field is small
enough, we show that the groundstate solution is unique up to magnetic
translations and rotations in the complex phase space, that groundstate
solutions share the rotational invariance of the magnetic field and that the
presence of a magnetic field induces a Gaussian decay. In this small magnetic
field r\'egime, the corresponding ground-energy is a convex differentiable
function of the magnetic field.


title:
Sparse l1 Regularisation of Matrix Valued Models for Acoustic Source
  Characterisation

abstract:
  We present a strategy for the recovery of a sparse solution of a common
problem in acoustic engineering, which is the reconstruction of sound source
levels and locations applying microphone array measurements. The considered
task bears similarities to the basis pursuit formalism but also relies on
additional model assumptions that are challenging from a mathematical point of
view. Our approach reformulates the original task as a convex optimisation
model. The sought solution shall be a matrix with a certain desired structure.
We enforce this structure through additional constraints. By combining popular
splitting algorithms and matrix differential theory in a novel framework we
obtain a numerically efficient strategy. Besides a thorough theoretical
consideration we also provide an experimental setup that certifies the
usability of our strategy. Finally, we also address practical issues, such as
the handling of inaccuracies in the measurement and corruption of the given
data. We provide a post processing step that is capable of yielding an almost
perfect solution in such circumstances.


title: On a four-loop form factor in N=4

abstract:
  We report on progress toward computing a four-loop supersymmetric form factor
in maximally supersymmetric Yang-Mills theory. A representative example
particle content from the involved supermultiplets is a stress-tensor operator
with two on-shell gluons. In previous work, the integrand for this form factor
was obtained using color-kinematic duality in a particularly simple form. Here
the result of applying integration-by-parts identities is discussed and
cross-checks of the result is performed. Rational IBP relations and their
reduction are introduced as a potentially useful aide.


title: Vainshtein mechanism in massive gravity nonlinear sigma models

abstract:
  We study the stability of the Vainshtein screening solution of the
massive/bi-gravity based on the massive nonlinear sigma model as the effective
action inside the Vainshtein radius. The effective action is obtained by taking
the $\Lambda_2$ decoupling limit around a curved spacetime. First we derive a
general consequence that any Ricci flat Vainshtein screening solution is
unstable when we take into account the excitation of the scalar graviton only.
This instability suggests that the nonlinear excitation of the scalar graviton
is not sufficient to obtain a successful Vainshtein screening in
massive/bi-gravity. Then to see the role of the excitation of the vector
graviton, we study perturbations around the static and spherically symmetric
solution obtained in bigravity explicitly. As a result, we find that linear
excitations of the vector graviton cannot be helpful and the solution still
suffers from a ghost and/or a gradient instability for any parameters of the
theory for this background.


title: Blockchain-based Proof of Location

abstract:
  Location-Based Services (LBSs) build upon geographic information to provide
users with location-dependent functionalities. In such a context, it is
particularly important that geographic locations claimed by users are
trustworthy. Centralized verification approaches proposed in the last few years
are not satisfactory, as they entail a high risk to the privacy of users. In
this paper, we present and evaluate a novel decentralized,
infrastructure-independent proof-of-location scheme based on blockchain
technology. Our scheme guarantees both location trustworthiness and user
privacy preservation.


title: 13-Moment System with Global Hyperbolicity for Quantum Gas

abstract:
  We point out that the quantum Grad's 13-moment system [R. Yano, Physica A:
Statistical Mechanics and its Applications, 416:231-241, 2014] is lack of
global hyperbolicity, and even worse, the thermodynamic equilibrium is not an
interior point of the hyperbolicity region of the system. To remedy this
problem, by fully considering Grad's expansion, we split the expansion into the
equilibrium part and the non-equilibrium part, and propose a regularization for
the system with the help of the new theory developed in [Z. Cai et al., SIAM J.
Appl. Math., 75(5):2001-2023, 2015, Y. Fan, J. Stat. Phys., 161(4), 2015]. This
provides us a new model which is hyperbolic for all admissible thermodynamic
states, and meanwhile preserves the approximate accuracy of the original
system. It should be noted that this procedure is not a trivial application of
the theory in [Z. Cai et al., SIAM J. Appl. Math., 75(5):2001-2023, 2015, Y.
Fan, J. Stat. Phys., 161(4), 2015].


title: On Semicovering, Subsemicovering and Subcovering Maps

abstract:
  In this paper, by reviewing the concept of subcovering and semicovering maps,
we extend the notion of subcovering map to subsemicovering map. We present some
necessary or sufficient conditions for a local homeomorphism to be a
subsemicovering map. Moreover, we investigate the relationship between these
conditions by some examples. Finally, we give a necessary and sufficient
condition for a subsemicovering map to be semicovering.


title:
Global classical solutions and large-time behavior of the two-phase
  fluid model

abstract:
  We study the global existence of a unique strong solution and its large-time
behavior of a two-phase fluid system consisting of the compressible isothermal
Euler equations coupled with compressible isentropic Navier-Stokes equations
through a drag forcing term. The coupled system can be derived as the
hydrodynamic limit of the Vlasov-Fokker-Planck/isentropic Navier-Stokes
equations with strong local alignment forces. When the initial data is
sufficiently small and regular, we establish the unique existence of the global
$H^s$-solutions in a perturbation framework. We also provide the large-time
behavior of classical solutions showing the alignment between two fluid
velocities exponentially fast as time evolves. For this, we construct a
Lyapunov function measuring the fluctuations of momentum and mass from its
averaged quantities.


title: MPI Derived Datatypes: Performance Expectations and Status Quo

abstract:
  We examine natural expectations on communication performance using MPI
derived datatypes in comparison to the baseline, "raw" performance of
communicating simple, non-contiguous data layouts. We show that common MPI
libraries sometimes violate these datatype performance expectations, and
discuss reasons why this happens, but also show cases where MPI libraries
perform well. Our findings are in many ways surprising and disappointing.
First, the performance of derived datatypes is sometimes worse than the
semantically equivalent packing and unpacking using the corresponding MPI
functionality. Second, the communication performance equivalence stated in the
MPI standard between a single contiguous datatype and the repetition of its
constituent datatype does not hold universally. Third, the heuristics that are
typically employed by MPI libraries at type-commit time are insufficient to
enforce natural performance guidelines, and better type normalization
heuristics may have a significant performance impact. We show cases where all
the MPI type constructors are necessary to achieve the expected performance for
certain data layouts. We describe our benchmarking approach to verify the
datatype performance guidelines, and present extensive verification results for
different MPI libraries.


title:
Centers of inscribed circles in triangular orbits of an elliptic
  billiard

abstract:
  The locus of centers of inscribed circles in triangles, the 3-periodic orbits
of an elliptic billiard, is also an ellipse. In this work we obtain the
canonical equation of this ellipse, complementing the previous results obtained
by O. Romaskevich.


title:
Testing anthropic reasoning for the cosmological constant with a
  realistic galaxy formation model

abstract:
  The anthropic principle is one of the possible explanations for the
cosmological constant ($\Lambda$) problem. In previous studies, a dark halo
mass threshold comparable with our Galaxy must be assumed in galaxy formation
to get a reasonably large probability of finding the observed small value,
$P(<$$\Lambda_{\rm obs})$, though stars are found in much smaller galaxies as
well. Here we examine the anthropic argument by using a semi-analytic model of
cosmological galaxy formation, which can reproduce many observations such as
galaxy luminosity functions. We calculate the probability distribution of
$\Lambda$ by running the model code for a wide range of $\Lambda$, while other
cosmological parameters and model parameters for baryonic processes of galaxy
formation are kept constant. Assuming that the prior probability distribution
is flat per unit $\Lambda$, and that the number of observers is proportional to
stellar mass, we find $P(<$$\Lambda_{\rm obs}) = 6.7 \%$ without introducing
any galaxy mass threshold. We also investigate the effect of metallicity; we
find $P(<$$\Lambda_{\rm obs}) = 9.0 \%$ if observers exist only in galaxies
whose metallicity is higher than the solar abundance. If the number of
observers is proportional to metallicity, we find $P(<$$\Lambda_{\rm obs}) =
9.7 \%$. Since these probabilities are not extremely small, we conclude that
the anthropic argument is a viable explanation, if the value of $\Lambda$
observed in our universe is determined by a probability distribution.


title: On the First Order Cohomology of Infinite--Dimensional Unitary Groups

abstract:
  The irreducible unitary highest weight representations
$(\pi_\lambda,\mathcal{H}_\lambda)$ of the group $U(\infty)$, which is the
countable direct limit of the compact unitary groups $U(n)$, are classified by
the orbits of the weights $\lambda \in \mathbb{Z}^{\mathbb{N}}$ under the Weyl
group $S_{(\mathbb{N})}$ of finite permutations. Here, we determine those
weights $\lambda$ for which the first cohomology space
$H^1(U(\infty),\pi_\lambda,\mathcal{H}_\lambda)$ vanishes. For finitely
supported $\lambda \neq 0$, we find that the first cohomology space
$H^1(U(\infty),\pi_\lambda,\mathcal{H}_\lambda)$ never vanishes. For these
$\lambda$, the highest weight representations extend to norm-continuous
irreducible representations of the full unitary group $U(\mathcal{H})$ (for
$\mathcal{H}:= \ell^2(\mathbb{N},\mathbb{C})$) endowed with the strong operator
topology and to norm-continuous representations of the unitary groups
$U_p(\mathcal{H})$ ($p\in [1,\infty]$) consisting of those unitary operators
$g\in U(\mathcal{H})$ for which $g-\mathbb{1}$ is of $p$th Schatten class.
However, not every 1-cocycle on $U(\infty)$ automatically extends to one on
these unitary groups, so we may not conclude that the first cohomology spaces
of the extended representations are non-vanishing. On the contrary, for the
groups $U(\mathcal{H})$ and $U_\infty(\mathcal{H})$, all first cohomology
spaces vanish. This is different for the groups $U_p(\mathcal{H})$ with $1\leq
p <\infty$, where only the natural representation on $\mathcal{H}$ and on its
dual have vanishing first cohomology spaces.


title: Surface state decoherence in loop quantum gravity, a first toy model

abstract:
  The quantum-to-classical transition through decoherence is a major facet of
the semi-classical analysis of quantum models that are supposed to admit a
classical regime, as quantum gravity should be. A particular problem of
interest is the decoherence of black hole horizons and holographic screens
induced by the bulk-boundary coupling with interior degrees of freedom. Here in
this paper we present a first toy-model, in the context of loop quantum
gravity, for the dynamics of a surface geometry as an open quantum system at
fixed total area. We discuss the resulting decoherence and recoherence and
compare the exact density matrix evolution to the commonly used master equation
approximation {\it \`a la} Lindblad underlining its merits and limitations. The
prospect of this study is to have a clearer understanding of the boundary
decoherence of black hole horizons seen by outside observers.


title:
Parametrized post-Newtonian equations of motion of N mass monopoles with
  the SEP violation

abstract:
  Post-Newtonian equations of motion of a system of $N$ mass monopoles in the
framework of the PPN formalism with two parameters $\beta$ and $\gamma$ are
derived for the case when the Strong Equivalence Principle can be violated. The
derivation is based on the previously published general framework. The
multipole moments of each body are defined as a PPN-generalization of the
corresponding Blanchet-Damour multiple moments in a relevant local reference
system defined for that body. The classical ten integrals of the derived
equations of motion are given. A special version of the equations of motion,
for which seven of these integrals are exact, is discussed. The derived
equations of motion can be used to test the Strong Equivalence Principle in
various solar system experiments.


title:
Constraining $f(R)$ Gravity Theory Using Weak Lensing Peak Statistics
  from the Canada-France-Hawaii-Telescope Lensing Survey

abstract:
  In this Letter, we report the observational constraints on the Hu-Sawicki
$f(R)$ theory derived from weak lensing peak abundances, which are closely
related to the mass function of massive halos. In comparison with studies using
optical or x-ray clusters of galaxies, weak lensing peak analyses have the
advantages of not relying on mass-baryonic observable calibrations. With
observations from the Canada-France-Hawaii-Telescope Lensing Survey, our peak
analyses give rise to a tight constraint on the model parameter $|f_{R0}|$ for
$n=1$. The $95\%$ CL limit is $\log_{10}|f_{R0}| < -4.82$ given WMAP9 priors on
$(\Omega_{\rm m}, A_{\rm s})$. With Planck15 priors, the corresponding result
is $\log_{10}|f_{R0}| < -5.16$.


title: Network Simplification for Secure AF Relaying

abstract:
  We consider a class of Gaussian layered networks where a source communicates
with a destination through L intermediate relay layers with N nodes in each
layer in the presence of a single eavesdropper which can overhear the
transmissions of the nodes in the last layer. For such networks we address the
question: what fraction of maximum secure achievable rate can be maintained if
only a fraction of available relay nodes are used in each layer? In particular,
we provide upper bounds on additive and multiplicative gaps between the optimal
secure AF when all N relays in each layer are used and when only k, 1 <= k < N,
relays are used in each layer. We show that asymptotically (in source power),
the additive gap increases at most logarithmically with ratio N/k and L, and
the corresponding multiplicative gap increases at most quadratically with ratio
N/k and L. To the best of our knowledge, this work offers the first
characterization of the performance of network simplification in layered
amplify-and-forward relay networks in the presence of an eavesdropper.


title:
Throwing fuel on the embers: Probability or Dichotomy, Cognitive or
  Linguistic?

abstract:
  Prof. Robert Berwick's abstract for his forthcoming invited talk at the
ACL2016 workshop on Cognitive Aspects of Computational Language Learning
revives an ancient debate. Entitled "Why take a chance?", Berwick seems to
refer implicitly to Chomsky's critique of the statistical approach of Harris as
well as the currently dominant paradigms in CoNLL.
  Berwick avoids Chomsky's use of "innate" but states that "the debate over the
existence of sophisticated mental grammars was settled with Chomsky's Logical
Structure of Linguistic Theory (1957/1975)", acknowledging that "this debate
has often been revived".
  This paper agrees with the view that this debate has long since been settled,
but with the opposite outcome! Given the embers have not yet died away, and the
questions remain fundamental, perhaps it is appropriate to refuel the debate,
so I would like to join Bob in throwing fuel on this fire by reviewing the
evidence against the Chomskian position!


title: Wegner estimate for Landau-breather Hamiltonians

abstract:
  We consider Landau Hamiltonians with a weak coupling random electric
potential of breather type.
  Under appropriate assumptions we prove a Wegner estimate.
  It implies the Hoelder continuity of the integrated density of states.
  The main challenge is the problem how to deal with non-linear dependence on
the random parameters.


title:
Higgs phase in a gauge $\mathbf{U}(1)$ non-linear $\mathbf{CP}^1$-model.
  Two species of BPS vortices and their zero modes

abstract:
  In this paper zero modes of fluctuation are dissected around the two species
of BPS vortices existing in the critical Higgs phase, where the scalar and
vector meson masses are equal, of a gauged $\mathbb{U}(1)$ nonlinear
$\mathbb{CP}^1$-model. If $2\pi n$, $n\in \mathbb{Z}$, is the quantized
magnetic flux of the two species of BPS vortex solutions, $2n$ linearly
independent vortex zero modes for each species are found and described. The
existence of two species of moduli spaces of dimension $2n$ of these stringy
topological defects is thus locally shown.


title:
Nonergodic subdiffusion from transient interactions with heterogeneous
  partners

abstract:
  Spatiotemporal disorder has been recently associated to the occurrence of
anomalous nonergodic diffusion of molecular components in biological systems,
but the underlying microscopic mechanism is still unclear. We introduce a model
in which a particle performs continuous Brownian motion with changes of
diffusion coefficients induced by transient molecular interactions with
diffusive binding partners. In spite of the exponential distribution of waiting
times, the model shows subdiffusion and nonergodicity similar to the
heavy-tailed continuous time random walk. The dependence of these properties on
the density of binding partners is analyzed and discussed. Our work provide an
experimentally-testable microscopic model to investigate the nature of
nonergodicity in disordered media.


title: Bender-Wu singularities

abstract:
  We consider a family of quantum Hamiltonians $H_\hbar=-\hbar^2\,(d^2\!/dx^2)
+V(x)$, $x\in\mathbb{R},$ $\hbar>0,$ where $V(x)=i(x^3-x)$ is an imaginary
double well potential. We prove the existence of infinite eigenvalue crossings
with the selection rules of the eigenvalue pairs taking part in a crossing.
This is a semiclassical localization effect. The eigenvalues at the crossings
accumulate at a critical energy for some of the Stokes lines.


title:
On supersymmetric Anti-de-Sitter, de-Sitter and Minkowski flux
  backgrounds

abstract:
  We test the robustness of the conditions required for the existence of
(supersymmetric) warped flux anti-de Sitter, de Sitter, and Minkowski
backgrounds in supergravity theories using as examples suitable foliations of
anti-de Sitter spaces. We find that there are supersymmetric de Sitter
solutions in supergravity theories including maximally supersymmetric ones in
10- and 11-dimensional supergravities. Moreover, warped flux Minkowski
backgrounds can admit Killing spinors which are not Killing on the Minkowski
subspace and therefore cannot be put in a factorized form.


title: Bi-Hermitian metrics on Kato surfaces

abstract:
  We investigate bi-Hermitian metrics on compact complex surfaces with odd
first Betti number producing new examples with connected anti-canonical divisor
using the general construction of \cite{abd15}. The result is a complete
classification for all \it unbranched \rm Kato surfaces and a classification up
to logarithmic deformation for \it intermediate \rm surfaces.


title:
Prompt atmospheric neutrino fluxes: perturbative QCD models and nuclear
  effects

abstract:
  We evaluate the prompt atmospheric neutrino flux at high energies using three
different frameworks for calculating the heavy quark production cross section
in QCD: NLO perturbative QCD, $k_T$ factorization including low-$x$
resummation, and the dipole model including parton saturation. We use QCD
parameters, the value for the charm quark mass and the range for the
factorization and renormalization scales that provide the best description of
the total charm cross section measured at fixed target experiments, at RHIC and
at LHC. Using these parameters we calculate differential cross sections for
charm and bottom production and compare with the latest data on forward charm
meson production from LHCb at $7$ TeV and at $13$ TeV, finding good agreement
with the data. In addition, we investigate the role of nuclear shadowing by
including nuclear parton distribution functions (PDF) for the target air
nucleus using two different nuclear PDF schemes. Depending on the scheme used,
we find the reduction of the flux due to nuclear effects varies from $10\%$ to
$50 \%$ at the highest energies. Finally, we compare our results with the
IceCube limit on the prompt neutrino flux, which is already providing valuable
information about some of the QCD models.


title: Correlation-induced DNA adsorption on like-charged membranes

abstract:
  The adsorption of DNA or other polyelectrolyte molecules on charged membranes
is a recurrent motif in soft matter and bionanotechnological systems. Two
typical situations encountered are the deposition of single DNA chains onto
substrates for further analysis, e.g., by force microscopy, or the pulling of
polyelectrolytes into membrane nanopores, as in sequencing applications. In
this paper, we present a theoretical analysis of such scenarios based on the
self-consistent field theory approach, which allows us to address the important
effect of charge correlations. We calculate the grand potential of a stiff
polyelectrolyte immersed in an electrolyte in contact with a negatively charged
dielectric membrane. For the sake of conciseness, we neglect conformational
polymer fluctuations and model the molecule as a rigid charged line. At
strongly charged membranes, the adsorbed counterions enhance the screening
ability of the interfacial region. In the presence of highly charged polymers
such as double-stranded DNA molecules close to the membrane, this enhanced
interfacial screening dominates the mean-field level DNA-membrane repulsion and
results in the adsorption of the DNA molecule to the surface. This picture
provides a simple explanation for the recently observed DNA binding onto
similarly charged substrates [G. L.-Caballero et al., Soft Matter 10, 2805
(2014)] and points out charge correlations as a non-negligible ingredient of
polymer-surface interactions.


title:
Aerodynamic Heating in Hypersonic Boundary Layers:\ Role of Dilatational
  Waves

abstract:
  The evolution of multi-mode instabilities in a hypersonic boundary layer and
their effects on aerodynamic heating are investigated. Experiments are
conducted in a Mach 6 wind tunnel using Rayleigh-scattering flow visualization,
fast-response pressure sensors, fluorescent temperature-sensitive paint (TSP),
and particle image velocimetry (PIV). Calculations are also performed based on
both parabolized stability equations (PSE) and direct numerical simulations
(DNS). It is found that second-mode dilatational waves, accompanied by
high-frequency alternating fluid compression and expansion, produce intense
aerodynamic heating in a small region that rapidly heats the fluid passing
through it. As a result, the surface temperature rapidly increases and results
in an overshoot over the nominal transitional value. When the dilatation waves
decay downstream, the surface temperature decreases gradually until transition
is completed. A theoretical analysis is provided to interpret the temperature
distribution affected by the aerodynamic heating.


title:
Three Hopf algebras from number theory, physics & topology, and their
  common background I: operadic & simplicial aspects

abstract:
  We consider three a priori totally different setups for Hopf algebras from
number theory, mathematical physics and algebraic topology. These are the Hopf
algebra of Goncharov for multiple zeta values, that of Connes-Kreimer for
renormalization, and a Hopf algebra constructed by Baues to study double loop
spaces. We show that these examples can be successively unified by considering
simplicial objects, co-operads with multiplication and Feynman categories at
the ultimate level. These considerations open the door to new constructions and
reinterpretations of known constructions in a large common framework, which is
presented step-by-step with examples throughout. In this first part of two
papers, we concentrate on the simplicial and operadic aspects.

categories: math.AT hep-th math-ph math.AG math.CT math.MP


title: Optimal insider control of stochastic partial differential equations

abstract:
  We study the problem of optimal inside control of an SPDE (a stochastic
evolution equation) driven by a Brownian motion and a Poisson random measure.
Our optimal control problem is new in two ways: (i) The controller has access
to inside information, i.e. access to information about a future state of the
system, (ii) The integro-differential operator of the SPDE might depend on the
control.
  In the first part of the paper, we formulate a sufficient and a necessary
maximum principle for this type of control problem, in two cases: (1) When the
control is allowed to depend both on time t and on the space variable x. (2)
When the control is not allowed to depend on x.
  In the second part of the paper, we apply the results above to the problem of
optimal control of an SDE system when the inside controller has only noisy
observations of the state of the system. Using results from nonlinear
filtering, we transform this noisy observation SDE inside control problem into
a full observation SPDE insider control problem.
  The results are illustrated by explicit examples.


title: Sharing Network Parameters for Crosslingual Named Entity Recognition

abstract:
  Most state of the art approaches for Named Entity Recognition rely on hand
crafted features and annotated corpora. Recently Neural network based models
have been proposed which do not require handcrafted features but still require
annotated corpora. However, such annotated corpora may not be available for
many languages. In this paper, we propose a neural network based model which
allows sharing the decoder as well as word and character level parameters
between two languages thereby allowing a resource fortunate language to aid a
resource deprived language. Specifically, we focus on the case when limited
annotated corpora is available in one language ($L_1$) and abundant annotated
corpora is available in another language ($L_2$). Sharing the network
architecture and parameters between $L_1$ and $L_2$ leads to improved
performance in $L_1$. Further, our approach does not require any hand crafted
features but instead directly learns meaningful feature representations from
the training data itself. We experiment with 4 language pairs and show that
indeed in a resource constrained setup (lesser annotated corpora), a model
jointly trained with data from another language performs better than a model
trained only on the limited corpora in one language.


title: Geometric inequalities in spherically symmetric spacetimes

abstract:
  In geometric inequalities ADM mass plays more fundamental role than the
concept of quasi-local mass. This paper is to demonstrate that using the
quasi-local mass some new insights can be acquired. In spherically symmetric
spacetimes the Misner-Sharp mass and the concept of the Kodama vector field
provides an ideal setting to the investigations of geometric inequalities. We
applying the proposed new techniques to investigate the spacetimes containing
black hole or cosmological horizons but we shall also apply them in context of
normal bodies. Most of the previous investigations applied only the quasi-local
charges and the area. Our main point is to include the quasi-local mass in the
corresponding geometrical inequalities. This way we recover some known
relations but new inequalities are also derived.


title:
An explicit asymptotic preserving low Froude scheme for the multilayer
  shallow water model with density stratification

abstract:
  We present an explicit scheme for a two-dimensional multilayer shallow water
model with density stratification, for general meshes and collocated variables.
The proposed strategy is based on a regularized model where the transport
velocity in the advective fluxes is shifted proportionally to the pressure
potential gradient. Using a similar strategy for the potential forces, we show
the stability of the method in the sense of a discrete dissipation of the
mechanical energy, in general multilayer and non-linear frames. These results
are obtained at first-order in space and time and extended using a simple
second-order MUSCL extension. With the objective of minimizing the diffusive
losses in realistic contexts, sufficient conditions are exhibited on the
regularizing terms to ensure the scheme's linear stability at first and
second-order in time and space. The other main result stands in the consistency
with respect to the asymptotics reached at small and large time scales in low
Froude regimes, which governs large-scale oceanic circulation. Additionally,
robustness and well-balanced results for motionless steady states are also
ensured. These stability properties tend to provide a very robust and efficient
approach, easy to implement and particularly well suited for large-scale
simulations. Some numerical experiments are proposed to highlight the scheme
efficiency: an experiment of fast gravitational modes, a smooth surface wave
propagation, an initial propagating surface water elevation jump considering a
non trivial topography, and a last experiment of slow Rossby modes simulating
the displacement of a baroclinic vortex subject to the Coriolis force.


title:
Dynamics of trapped interacting vortices in Bose-Einstein condensates:
  Role of breathing degree of freedom

abstract:
  With use of a variational principle, we investigate a role of breathing width
degree of freedom in the effective theory of interacting vortices in a trapped
single-component Bose-Einstein condensates in 2 dimensions under the strong
repulsive cubic nonlinearity. As for the trial function, we choose a product of
two vortex functions assuming a pair interaction and employ the amplitude form
of each vortex function in the Pad\'e approximation which accommodates a
hallmark of the vortex core. We have obtained Lagrange equation for the
interacting vortex-core coordinates coupled with the time-derivative of width
and also its Hamilton formalism by having recourse to a non-standard Poisson
bracket. By solving the Hamilton equation, we find rapid radial breathing
oscillations superposed on the slower rotational motion of vortex cores,
consistent with numerical solutions of Gross-Pitaevskii equation. In
higher-energy states of 2 vortex systems, the breathing width degree of freedom
plays role of a kicking in the kicked rotator and generates chaos with a
structure of sea-urchin needles. Byproduct of the present variational approach
includes: (1) the charge-dependent logarithmic inter-vortex interaction
multiplied with a pre-factor which depends on the scalar product of a pair of
core-position vectors; (2) the charge-independent short-range repulsive
inter-vortex interaction and spring force.


title: The International Linear Collider - Physics and Perspectives

abstract:
  With the discovery of a Higgs boson at LHC, all particles of the Standard
Model seem to have been observed experimentally, yet many questions are left
unanswered. The discovery has intensified the planning for future high-energy
colliders, which aim to probe the Standard Model and the mechanism of
electroweak symmetry breaking with higher precision and to extend and
complement the search for new particles currently under way at the LHC. The
most mature option for such a future facility is the International Linear
Collider ILC, an electron-positron collider with a centre-of-mass energy of 500
GeV, and the potential for upgrades into the TeV region. The ILC will fully
explore the Higgs sector, including model-independent coupling and width
measurements, direct measurements of the coupling to the top quark and the
Higgs self-coupling, enable precision measurements of top quark properties and
couplings as well as other electroweak precision measurements and provide
extensive discovery potential for new physics complementary to the capabilities
of hadron colliders. This paper will give an overview of the physics case of
the ILC, put in context of the running scenario covering different
centre-of-mass energies, and discuss the current status and perspectives of
this global facility.


title: Transport, shot noise, and topology in AC-driven dimer arrays

abstract:
  We analyze an AC-driven dimer chain connected to a strongly biased electron
source and drain. It turns out that the resulting transport exhibits
fingerprints of topology. They are particularly visible in the driving-induced
current suppression and the Fano factor. Thus, shot noise measurements provide
a topological phase diagram as a function of the driving parameters. The
observed phenomena can be explained physically by a mapping to an effective
time-independent Hamiltonian and the emergence of edge states. Moreover, by
considering quantum dissipation, we determine the requirements for the
coherence properties in a possible experimental realization. For the
computation of the zero-frequency noise, we develop an efficient method based
on matrix-continued fractions.


title:
Consistent simulation of non-resonant diphoton production in hadron
  collisions including associated jet production up to two jets

abstract:
  An event generator for diphoton ($\gamma\gamma$) production in hadron
collisions that includes associated jet production up to two jets has been
developed using a subtraction method based on the LLL subtraction. The parton
shower (PS) simulation to restore the subtracted divergent components involves
both QED and QCD radiation, and QED radiation at very small $Q^{2}$ are
simulated by referring to a fragmentation function (FF). The PS/FF simulation
has the ability to enforce the radiation of a given number of energetic
photons. The generated events can be fed to PYTHIA to obtain particle
(hadron)-level event information, which enables us to perform realistic
simulations of photon isolation and hadron-jet reconstruction. The simulated
events, in which the loop-mediated $gg \rightarrow \gamma\gamma$ process is
involved, reasonably reproduce the diphoton kinematics measured at the LHC.
Using the developed simulation, we found that the 2-jet processes significantly
contribute to diphoton production. A large 2-jet contribution can be considered
as a common feature in electroweak-boson production in hadron collisions
although the reason is yet to be understood. Discussion concerning the
treatment of the underlying events in photon isolation is necessary for future
higher precision measurements.


title: An Easton-like theorem for Zermelo-Fraenkel Set Theory without Choice

abstract:
  We show that in Zermelo-Fraenkel Set Theory without the Axiom of Choice a
surjectively modified continuum function $\theta(\kappa)$ can take almost
arbitrary values for all infinite cardinals. This choiceless version of
Easton's Theorem is in sharp contrast to the situation in ZFC, where for
singular cardinals $\kappa$, the value of $2^\kappa$ is strongly influenced by
the behaviour of the continuum function below.
  Our construction can roughly be described as follows: In a ground model $V
\models ZFC + GCH$ with a "reasonable" function $F: Card \rightarrow Card$ on
the infinite cardinals, a class forcing ${\mathbb P}$ is introduced, which
blows up the power sets of all cardinals according to $F$ . The eventual model
$N \models ZF$ is a symmetric extension by ${\mathbb P}$ such that
$\theta^N(\kappa) = F(\kappa)$ holds for all $\kappa$.


title: A Characterization of Wishart Processes and Wishart Distributions

abstract:
  A characterization of the existence of non-central Wishart distributions
(with shape and non-centrality parameter) as well as the existence of solutions
to Wishart stochastic differential equations (with initial data and drift
parameter) in terms of their exact parameter domains is given. These two
families are the natural extensions of the non-central chi-square distributions
and the squared Bessel processes to the positive semidefinite matrices.


title:
Frequency tripled 1542 nm telecom laser diode stabilized to iodine
  hyperfine line in the 10-15 range

abstract:
  We report on telecom laser frequency stabilization to narrow iodine hyperfine
line in the green range of the optical domain, after a frequency tripling
process using two nonlinear PPLN crystals. We have generated up to 300 mW
optical power in the green (P3w), from 800 mW of infrared power (Pw). This
result corresponds to an optical conversion efficiency eta= P3w/Pw ~ 36 %. To
our knowledge, this is the best value ever demonstrated for a CW frequency
tripling process. We have used a narrow linewidth iodine hyperfine line
(component a1 of the 127I2 R 35 (44-0) line) to stabilize the IR laser yielding
to frequency stability of 4.8x10-14 t-1/2 with a minimum of 6x10-15 reached
after 50 s of integration time. The whole optical setup is very compact and
mostly optically fibered. This approach opens the way for efficient and elegant
architecture development for space applications as one of several potential
uses.


title: An Optimal Algorithm for Range Search on Multidimensional Points

abstract:
  This paper proposes an efficient and novel method to address range search on
multidimensional points in $\theta(t)$ time, where $t$ is the number of points
reported in $\Re^k$ space. This is accomplished by introducing a new data
structure, called BITS $k$d-tree. This structure also supports fast updation
that takes $\theta(1)$ time for insertion and $O(\log n)$ time for deletion.
The earlier best known algorithm for this problem is $O(\log^k n+t)$ time in
the pointer machine model.


title: Nonlinear Dynamic Force Spectroscopy

abstract:
  Dynamic force spectroscopy (DFS) is an experimental technique that is
commonly used to assess information of the strength, energy landscape, and
lifetime of noncovalent bio-molecular interactions. DFS traditionally requires
an applied force that increases linearly with time so that the bio-complex
under investigation is exposed to a constant loading rate. However, tethers or
polymers can modulate the applied force in a nonlinear regime. For example,
bacterial adhesion pili and polymers with worm-like chain properties are
examples of structures that show nonlinear force responses. In these
situations, the theory for traditional DFS cannot be readily applied. In this
work we expand the theory for DFS to also include nonlinear external forces
while still maintaining compatibility with the linear DFS theory. To validate
the theory we modeled a bio-complex expressed on a stiff, an elastic and a
worm-like chain polymer, using Monte Carlo methods, and assessed the
corresponding rupture force spectra. It was found that the nonlinear DFS
(NLDFS) theory correctly predicted the numerical results. We also present a
protocol suggesting an experimental approach and analysis method of the data to
estimate the bond length and the thermal off-rate.