title:
A second post-AGB nebula that contains gas in rotation and in expansion:
  ALMA maps of IW Car

abstract:
  We aim to study the presence of both rotation and expansion in post-AGB
nebulae, in particular around IW Car, a binary post-AGB star that was suspected
to be surrounded by a Keplerian disk. We obtained high-quality ALMA
observations of 12CO and 13CO J=3-2 lines in IW Car. The maps were analyzed by
means of a simplified model of CO emission, based on those used for similar
objects. Our observations clearly show the presence of gas components in
rotation, in an equatorial disk, and expansion, which shows an hourglass-like
structure with a symmetry axis perpendicular to the rotation plane and is
probably formed of material extracted from the disk. Our modeling can reproduce
the observations and shows moderate uncertainties. The rotation velocity
corresponds to a central stellar mass of approximately 1 Mo. We also derive the
total mass of the molecule-rich nebula, found to be of ~ 4 10e-3 Mo; the
outflow is approximately eight times less massive than the disk. From the
kinematical age of the outflow and the mass values derived for both components,
we infer a (future) lifetime of the disk of approximately 5000--10000 yr.


title:
New Ternary Superconducting Compound LaRu2As2: Physical Properties from
  DFT Calculations

abstract:
  In this paper, we have presented the density functional theory (DFT) based
calculations performed within the first-principles pseudopotential method to
investigate the physical properties of the newly discovered superconductor
LaRu2As2 for the first time. The optimized structural parameters are in good
agreement with the experimental results. The calculated independent elastic
constants ensure mechanical stability of the compound. The calculated Cauchy
pressure, Pugh's ratio as well as Poisson's ratio indicate that LaRu2As2 should
behave as a ductile material. Due to low Debye temperature, LaRu2As2 may be
used as a thermal barrier coating (TBC) material. The new compound should
exhibit metallic nature as its valence bands overlap considerably with the
conduction bands. LaRu2As2 is expected to be a soft material and easily
machineable because of its low hardness value of 6.8 Gpa. The multi-band nature
is observed in calculated Fermi surface. A highly anisotropic combination of
ionic, covalent, and metallic interactions is expected in accordance with
charge density calculations.


title:
Further Results on the Convergence of the Pavon-Ferrante Algorithm for
  Spectral Estimation

abstract:
  In this paper, we provide a detailed analysis of the global convergence
properties of an extensively studied and extremely effective fixed-point
algorithm for the Kullback-Leibler approximation of spectral densities,
proposed by Pavon and Ferrante in [Pavon and Ferrante, 2006]. Our main result
states that the algorithm globally converges to one of its fixed points.


title:
ARPES Studies of Two-Dimensional Electron Gases at Transition Metal
  Oxide Surfaces

abstract:
  High mobility two-dimensional electron gases (2DEGs) underpin today's silicon
based devices and are of fundamental importance for the emerging field of oxide
electronics. Such 2DEGs are usually created by engineering band offsets and
charge transfer at heterointerfaces. However, in 2011 it was shown that highly
itinerant 2DEGs can also be induced at bare surfaces of different transition
metal oxides where they are far more accessible to high resolution angle
resolved photoemission (ARPES) experiments. Here we review work from this
nascent field which has led to a systematic understanding of the subband
structure arising from quantum confinement of highly anisotropic transition
metal d-states along different crystallographic directions. We further discuss
the role of different surface preparations and the origin of surface 2DEGs, the
understanding of which has permitted control over 2DEG carrier densities.
Finally, we discuss signatures of strong many-body interactions and how
spectroscopic data from surface 2DEGs may be related to the transport
properties of interface 2DEGs in the same host materials.


title: Upper bound for the Dvoretzky dimension in Milman-Schechtman theorem

abstract:
  For a symmetric convex body $K\subset\mathbb{R}^n$, the Dvoretzky dimension
$k(K)$ is the largest dimension for which a random central section of $K$ is
almost spherical. A Dvoretzky-type theorem proved by V.~D.~Milman in 1971
provides a lower bound for $k(K)$ in terms of the average $M(K)$ and the
maximum $b(K)$ of the norm generated by $K$ over the Euclidean unit sphere.
Later, V.~D.~Milman and G. Schechtman obtained a matching upper bound for
$k(K)$ in the case when $\frac{M(K)}{b(K)}>c(\frac{\log(n)}{n})^{\frac{1}{2}}$.
  In this paper, we will give an elementary proof of the upper bound in
Milman-Schechtman theorem which does not require any restriction on $M(K)$ and
$b(K)$.


title: Groups that have the same holomorph as a finite perfect group

abstract:
  We describe the groups that have the same holomorph as a finite perfect
group. Our results are complete for centerless groups. When the center is
non-trivial, some questions remain open. The peculiarities of the general case
are illustrated by a couple of examples that might be of independent interest.


title:
Preconditioning trace coupled 3$d$-1$d$ systems using fractional
  Laplacian

abstract:
  Multiscale or multiphysics problems often involve coupling of partial
differential equations posed on domains of different dimensionality. In this
work we consider a simplified model problem of a 3d-1d coupling and the main
objective is to construct algorithms that may utilize stan- dard multilevel
algorithms for the 3d domain, which has the dominating computational
complexity. Preconditioning for a system of two elliptic problems posed,
respectively, in a three dimensional domain and an embedded one dimensional
curve and coupled by the trace constraint is discussed. Investigating
numerically the properties of the well-defined discrete trace operator, it is
found that negative fractional Sobolev norms are suitable preconditioners for
the Schur complement of the sys- tem. The norms are employed to construct a
robust block diagonal preconditioner for the coupled problem.


title: Nonadiabatic holonomic quantum computation with dressed-state qubits

abstract:
  Implementing holonomic quantum computation is a challenging task as it
requires complicated interaction among multilevel systems. Here we propose to
implement nonadiabatic holonomic quantum computation based on dressed-state
qubits in circuit QED. An arbitrary holonomic single-qubit gate can be
conveniently achieved using external microwave fields and tuning their
amplitudes and phases. Meanwhile, nontrivial two-qubit gates can be implemented
in a coupled-cavities scenario assisted by a grounding SQUID with tunable
interaction, where the tuning is achieved by modulating the ac flux threaded
through the SQUID. In addition, our proposal is directly scalable, up to a
two-dimensional lattice configuration. In the present scheme, the dressed
states involve only the lowest two levels of each transmon qubit and the
effective interactions exploited are all of resonant nature. Therefore, we
release the main difficulties for physical implementation of holonomic quantum
computation on superconducting circuits.


title: Convexity and the Dirichlet problem of translating mean curvature flows

abstract:
  In this work, we propose a new evolving geometric flow (called translating
mean curvature flow) for the translating solitons of hypersurfaces in
$R^{n+1}$. We study the basic properties, such as positivity preserving
property, of the translating mean curvature flow. The Dirichlet problem for the
graphical translating mean curvature flow is studied and the global existence
of the flow and the convergence property are also considered.


title: Anomalous couplings in WZ production beyond NLO QCD

abstract:
  We study WZ production with anomalous couplings at $\bar{n}$NLO QCD using the
LoopSim method in combination with the Monte Carlo program VBFNLO. Higher order
corrections to WZ production are dominated by additional hard jet radiation.
Those contributions are insensitive to anomalous couplings and should thus be
removed in analyses. We do this using a dynamical jet veto based on the
transverse energy of the QCD and EW final state particles. This removes jet
dominated events without introducing problematic logs like a fixed
$p_{\text{T}}$ jet veto.


title: Generalized fractional integration of k\-Bessel function

abstract:
  In this present paper our aim is to deal with two integral transforms which
involving the Gauss hypergeometric function as its kernels. We prove some
compositions formulas for such a generalized fractional integrals with k Bessel
function. The results are established in terms of generalized Wright type
hypergeometric function and generalized hypergeometric series. Also, the
authors presented some corresponding assertions for Riemann Liouville and
Erdelyi Kober fractional integral transforms.


title: Enumerating Cayley (di-)graphs on dihedral groups

abstract:
  Let $p$ be an odd prime, and $D_{2p}=\langle \tau,\sigma\mid
\tau^p=\sigma^2=e,\sigma\tau\sigma=\tau^{-1}\rangle$ the dihedral group of
order $2p$. In this paper, we provide the number of (connected) Cayley
(di-)graphs on $D_{2p}$ up to isomorphism by using the P\'{o}lya enumeration
theorem. In the process, we also enumerate (connected) Cayley digraphs on
$D_{2p}$ of out-degree $k$ up to isomorphism for each $k$.


title: Tunable band structure and effective mass of disordered chalcopyrite

abstract:
  Although new photovoltaic materials, such as organic perovskites, have
attracted much attention recently,\cite{perov1,perov2,perov3} zinc-blende
semiconductors still play an important role, owing to their high efficiency and
stability in real environments. For example, Cu$_2$ZnSnSe$_4$ \cite{AM2013}
(CZTS) and Cu(In,Ga)Se$_2$ \cite{JACS2008} (CIGS), which are both based on
chalcopyrite CuGa$X_2$ ($X=$ S, Se), have been considered as potential
candidates for photovoltaics. It has been reported recently that the efficiency
of CIGS has gone beyond 20\%, which is close to that of polycrystalline s
ilicon.\cite{efficiency2014} Furthermore, photovoltaic devices related to CZTS
have gained attention because they solely contain abundant and nontoxic
materials.\cite{AM2013,CZTS}


title: Microparticle assembly pathways on lipid membranes

abstract:
  Understanding interactions between microparticles and lipid membranes is of
increasing importance, especially for unraveling the influence of microplastics
on our health and environment. Here, we study how a short-ranged adhesive force
between microparticles and model lipid membranes causes membrane-mediated
particle assembly. Using confocal microscopy, we observe the initial particle
attachment to the membrane, then particle wrapping, and in rare cases
spontaneous membrane tubulation. In the attached state, we measure that the
particle mobility decreases by 26%. If multiple particles adhere to the same
vesicle, their initial single-particle state determines their interactions and
subsequent assembly pathways: 1) attached particles only aggregate when small
adhesive vesicles are present in solution, 2) wrapped particles reversibly
attract one another by membrane deformation, and 3) a combination of wrapped
and attached particles form membrane-mediated dimers, which further assemble
into a variety of complex structures. The experimental observation of distinct
assembly pathways induced only by a short ranged membrane-particle adhesion,
shows that a cellular cytoskeleton or other active components are not required
for microparticle aggregation. We suggest that this membrane-mediated
microparticle aggregation is a reason behind reported long retention times of
polymer microparticles in organisms.


title: The quantum harmonic Otto cycle

abstract:
  The quantum Otto cycle serves as a bridge between the macroscopic world of
heat engines and the quantum regime of thermal devices composed from a single
element. We compile recent studies of the quantum Otto cycle with a harmonic
oscillator as a working medium. This model has the advantage that it is
analytically trackable. In addition, an experimental realization has been
achieved employing a single ion in a harmonic trap. The review is embedded in
the field of quantum thermodynamics and quantum open systems. The basic
principles of the theory are explained by a specific example illuminating the
basic definitions of work and heat. The relation between quantum observables
and the state of the system is emphasized. The dynamical description of the
cycle is based on a completely positive map formulated as a propagator for each
stroke of the engine. Explicit solutions for these propagators are described on
a vector space of quantum thermodynamical observables. These solutions which
employ different assumptions and techniques are compared. The tradeoff between
power and efficiency is the focal point of finite-time-thermodynamics. The
dynamical model enables to study finite time cycles limiting time on the
adiabtic and the thermalization times. Explicit finite time solutions are found
which are frictionless, meaning that no coherence is generated also known as
shortcuts to adiabaticity. The transition from frictionless to sudden adiabats
is characterized by a non-hermitian degeneracy in the propagator. In addition
the influence of noise on the control is illustrated. These results are used to
close the cycles either as engines or as refrigerators.


title:
On the Pragmatic Design of Literature Studies in Software Engineering:
  An Experience-based Guideline

abstract:
  Systematic literature studies have received much attention in empirical
software engineering in recent years. They have become a powerful tool to
collect and structure reported knowledge in a systematic and reproducible way.
We distinguish systematic literature reviews to systematically analyze reported
evidence in depth, and systematic mapping studies to structure a field of
interest in a broader, usually quantified manner. Due to the rapidly increasing
body of knowledge in software engineering, researchers who want to capture the
published work in a domain often face an extensive amount of publications,
which need to be screened, rated for relevance, classified, and eventually
analyzed. Although there are several guidelines to conduct literature studies,
they do not yet help researchers coping with the specific difficulties
encountered in the practical application of these guidelines. In this article,
we present an experience-based guideline to aid researchers in designing
systematic literature studies with special emphasis on the data collection and
selection procedures. Our guideline aims at providing a blueprint for a
practical and pragmatic path through the plethora of currently available
practices and deliverables capturing the dependencies among the single steps.
The guideline emerges from various mapping studies and literature reviews
conducted by the authors and provides recommendations for the general study
design, data collection, and study selection procedures. Finally, we share our
experiences and lessons learned in applying the different practices of the
proposed guideline.


title:
Thermoelectric efficiency of quantum dot molecules at a high temperature
  bias: the role of thermal-induced voltage

abstract:
  The nonlinear electron and heat currents of quantum dot molecules (QDMs)
under a temperature bias are theoretically investigated, including all
correlation functions arising from electron Coulomb interactions in QDMs.
Unlike the case of double QDs, the maximum efficiency of serially coupled
triple QDs (SCTQD) occurs in the orbital depletion regime owing to the interdot
Coulomb blockade. The electron current in SCTQD shows a bipolar oscillatory
behavior with respect to the variation of QD energy levels, whereas the heat
current does not show such a behavior. This is mainly attributed to
thermal-induced bias. In addition, we illustrate how the efficiency of SCTQD is
influenced by the external load resistance, and phonon heat flow. Finally, a
direction-dependent electron current driven by a temperature bias has been
demonstrated for a SCTQD with staircase-like energy levels.


title: Polarization anisotropy of the emission from type-II quantum dots

abstract:
  We study the polarization response of the emission from type-II GaAsSb capped
InAs quantum dots. The theoretical prediction based on the calculations of the
overlap integrals of the single-particle states obtained in the k.p framework
is given. This is verified experimentally by polarization resolved
photoluminescence measurements on samples with the type-II confinement. We show
that the polarization anisotropy might be utilized to find the vertical
position of the hole wavefunction and its orientation with respect to
crystallographic axes of the sample. A proposition for usage in the information
technology as a room temperature photonic gate operating at the communication
wavelengths as well as a simple model to estimate the energy of fine-structure
splitting for type-II GaAsSb capped InAs QDs are given.


title:
Generation of the Trigonometric Cubic B-Spline Collocation Solutions for
  the Kuramoto-Sivashinsky(KS) Equation

abstract:
  A recent type of B-spline functions, namely trigonometric cubic B-splines,
are adapted to the collocation method for the numerical solutions of the
Kuramoto-Sivashinsky equation. Having only first and second order derivatives
of the trigonometric cubic B-splines at the nodes forces us to convert the
Kuramoto-Sivashinsky equation to a coupled system of equations by reducing the
order of the higher order terms. Crank-Nicolson method is applied for the time
integration of the space discretized system resulted by trigonometric cubic
B-spline approach. Some initial boundary value problems are solved to show the
validity of the proposed method.


title: Single-electron gap in the spectrum of twisted bilayer graphene

abstract:
  We investigate the gap in the single-electron spectrum of twisted bilayer
graphene. In a perfect infinite lattice of a twisted bilayer, the gap varies
exponentially in response to weak changes of the twist angle. Such a large
sensitivity makes theoretical predictions of the gap nearly impossible, since
experimentally the twist angle is always known with finite accuracy. To address
this issue, we numerically study finite clusters of twisted bilayer graphene.
For finite systems, changing the twist angle causes a gradual crossover between
gapless and gapped regimes. The crossover occurs when the finite-size
quantization energy becomes comparable to the matrix elements responsible for
the generation of the gap. We further argue that disorder scattering can induce
similar crossover, in which the mean-free path plays the same role as the
system size for the finite clusters. It is demonstrated that, to observe the
gap experimentally, it is necessary to have a sample of suitable purity, and to
possess the ability to tune the twist angle accurately.


title: Defective Galton-Watson processes

abstract:
  The Galton-Watson process is a Markov chain modeling the population size of
independently reproducing particles giving birth to $k$ offspring with
probability $p_k$, $k\ge0$. In this paper we consider {\it defective}
Galton-Watson processes having defective reproduction laws, so that
$\sum_{k\ge0}p_k=1-\eps$ for some $\eps\in(0,1)$. In this setting, each
particle may send the process to a graveyard state $\Delta$ with probability
$\eps$. Such a Markov chain, having an enhanced state space
$\{0,1,\ldots\}\cup\{\Delta\}$, gets eventually absorbed either at $0$ or at
$\Delta$. Assuming that the process has avoided absorption until the
observation time $t$, we are interested in its trajectories as $t\to\infty$ and
$\eps\to0$.


title: Evidence of topological insulator state in the semimetal LaBi

abstract:
  By employing angle-resolved photoemission spectroscopy combined with
first-principles calculations, we performed a systematic investigation on the
electronic structure of LaBi, which exhibits extremely large magnetoresistance
(XMR), and is theoretically predicted to possess band anticrossing with
nontrivial topological properties. Here, the observations of the Fermi-surface
topology and band dispersions are similar to previous studies on LaSb [Phys.
Rev. Lett. 117, 127204 (2016)], a topologically trivial XMR semimetal, except
the existence of a band inversion along the $\Gamma$-$X$ direction, with one
massless and one gapped Dirac-like surface state at the $X$ and $\Gamma$
points, respectively. The odd number of massless Dirac cones suggests that LaBi
is analogous to the time-reversal $Z_2$ nontrivial topological insulator. These
findings open up a new series for exploring novel topological states and
investigating their evolution from the perspective of topological phase
transition within the family of rare-earth monopnictides.


title:
Statistics of Visual Responses to Object Stimuli from Primate AIT
  Neurons to DNN Neurons

abstract:
  Cadieu et al. (Cadieu,2014) reported that deep neural networks(DNNs) could
rival the representation of primate inferotemporal cortex for object
recognition. Lehky et al. (Lehky,2011) provided a statistical analysis on
neural responses to object stimuli in primate AIT cortex. They found the
intrinsic dimensionality of object representations in AIT cortex is around 100
(Lehky,2014). Considering the outstanding performance of DNNs in object
recognition, it is worthwhile investigating whether the responses of DNN
neurons have similar response statistics to those of AIT neurons. Following
Lehky et al.'s works, we analyze the response statistics to image stimuli and
the intrinsic dimensionality of object representations of DNN neurons. Our
findings show in terms of kurtosis and Pareto tail index, the response
statistics on single-neuron selectivity and population sparseness of DNN
neurons are fundamentally different from those of IT neurons except some
special cases. By increasing the number of neurons and stimuli, the conclusions
could alter substantially. In addition, with the ascendancy of the
convolutional layers of DNNs, the single-neuron selectivity and population
sparseness of DNN neurons increase, indicating the last convolutional layer is
to learn features for object representations, while the following
fully-connected layers are to learn categorization features. It is also found
that a sufficiently large number of stimuli and neurons are necessary for
obtaining a stable dimensionality. To our knowledge, this is the first work to
analyze the response statistics of DNN neurons comparing with AIT neurons, and
our results provide not only some insights into the discrepancy of DNN neurons
with respect to IT neurons in object representation, but also shed some light
on possible outcomes of IT neurons when the number of recorded neurons and
stimuli is beyond the level in (Lehky,2011,2014).


title:
Physical Contact between the +20 km/s Cloud and the Galactic
  Circumnuclear Disk

abstract:
  This paper reports the discovery of evidence for physical contact between the
Galactic circumnuclear disk (CND) and an exterior giant molecular cloud. The
central 10 pc of our Galaxy has been imaged in the HCN J=1-0, HCO+ J=1-0, CS
J=2-1, H13CN J=1-0, SiO J=2-1, SO N_J=2_3-1_2, and HC3N J=11-10 lines using the
Nobeyama Radio Observatory 45 m radio telescope. Based on our examination of
the position-velocity maps of several high-density probe lines, we have found
that an emission "bridge" may be connecting the +20 km/s cloud (M-0.13-0.08)
and the negative-longitude extension of the CND. Analyses of line intensity
ratios imply that the chemical property of the bridge is located between the
+20 km/s cloud and the CND. We introduce a new interpretation that a part of
the CND may be colliding with the 20 km/s cloud and the collision may be
responsible for the formation of the bridge. Such collisional events could
promote mass accretion onto the CND or into the inner ionized cavity, which may
be further tested by proper motion studies.


title: Algorithms for Tight Spans and Tropical Linear Spaces

abstract:
  We describe a new method for computing tropical linear spaces and more
general duals of polyhedral subdivisions. It is based on Ganter's algorithm
(1984) for finite closure systems.


title:
Superconductivity in LiOHFeS single crystals with a shrunk c-axis
  lattice constant

abstract:
  By using a hydrothermal ion-exchange method, we have successfully grown
superconducting crystals of LiOHFeS with ${T_c}$ of about 2.8 K. Being
different from the sister sample (Li${_{1-x}}$Fe${_x}$)OHFeSe, the energy
dispersion spectrum analysis on LiOHFeS shows that the Fe/S ratio is very close
to 1:1, suggesting an almost charge neutrality and less electron doping in the
FeS planes of the system. Comparing with the non superconducting LiOHFeS
crystal, each peak of the X-ray diffraction pattern of the superconducting
crystal splits into two, and the diffraction peaks locating at lower reflection
angles are consistent with that of non-superconducting ones. The rest set of
diffraction peaks with higher reflection angles is corresponding to the
superconducting phase, suggesting that the superconducting phase may has a
shrunk c-axis lattice constant. Magnetization measurements indicate that the
magnetic shielding due to superconductivity can be quite high under a weak
magnetic field. The resistivity measurements under various magnetic fields show
that the upper critical field is quite low, which is similar to the tetragonal
FeS superconductor.


title:
Revisiting Graphene Oxide Chemistry via Spatially-Resolved Electron
  Energy Loss Spectroscopy

abstract:
  The type and distribution of oxygen functional groups in graphene oxide (GO)
and reduced graphene oxide (RGO) remain still a subject of great debate. Local
analytic techniques are required to access the chemistry of these materials at
a nanometric scale. Electron energy loss spectroscopy in a scanning
transmission electron microscope can provide the suitable resolution, but GO
and RGO are extremely sensitive to electron irradiation. In this work we employ
a dedicated experimental setup to reduce electron illumination below damage
limit. GO oxygen maps obtained at a few nanometers scale show separated domains
with different oxidation levels. The C/O ratio varies from about 4:1 to 1:1,
the latter corresponding to a complete functionalization of the graphene
flakes. In RGO the residual oxygen concentrates mostly in regions few tens
nanometers wide. Specific energy-loss near-edge structures are observed for
different oxidation levels. By combining these findings with first-principles
simulations we propose a model for the highly oxidized domains where graphene
is fully functionalized by hydroxyl groups forming a 2D-sp$^3$ carbon network
analogous to that of graphane.


title:
Multiblob coarse-graining for mixtures of long polymers and soft
  colloids

abstract:
  Soft nanocomposites represent both a theoretical and an experimental
challenge due to the high number of the microscopic constituents that strongly
influence the behaviour of the systems. An effective theoretical description of
such systems invokes a reduction of the degrees of freedom to be analysed,
hence requiring the introduction of an efficient, quantitative, coarse-grained
description. We here report on a novel coarse graining approach based on a set
of transferable potentials that quantitatively reproduces properties of
mixtures of linear and star-shaped homopolymeric nanocomposites. By
renormalizing groups of monomers into a single effective potential between a
$f$-functional star polymer and an homopolymer of length $N_0$, and through a
scaling argument, it will be shown how a substantial reduction of the to
degrees of freedom allows for a full quantitative description of the system.
Our methodology is tested upon full monomer simulations for systems of
different molecular weight, proving its full predictive potential.


title:
Type-II InAs/GaAsSb/GaAs quantum dots as artificial quantum dot
  molecules

abstract:
  We have studied theoretically the type-II GaAsSb capped InAs quantum dots for
two structures differing in the composition of the capping layer, being either
(i) constant or (ii) with Sb accumulation above the apex of the dot. We have
found that the hole states are segmented and resemble the states in the quantum
dot molecules. The two-hole states form singlet and triplet with the splitting
energy of 4{\mu}eV / 325{\mu}eV for the case (i) / (ii). We have also tested
the possibility to tune the splitting by vertically applied magnetic field. As
the predicted tunability range was limited, we propose an approach for its
enhancement.


title: Search Personalization with Embeddings

abstract:
  Recent research has shown that the performance of search personalization
depends on the richness of user profiles which normally represent the user's
topical interests. In this paper, we propose a new embedding approach to
learning user profiles, where users are embedded on a topical interest space.
We then directly utilize the user profiles for search personalization.
Experiments on query logs from a major commercial web search engine demonstrate
that our embedding approach improves the performance of the search engine and
also achieves better search performance than other strong baselines.


title:
A Simple Generic Model of Cellular Polarity Alignment: Derivation and
  Analysis

abstract:
  Ordered polarity alignment of a cell population plays a vital role in
biology, such as in hair follicle alignment and asymmetric cell division. Here,
we propose a theoretical framework for the understanding of generic dynamical
properties of polarity alignment in interacting cellular units, where each cell
is described by a reaction-diffusion system and the cells further interact with
one another through their proximal surfaces. The system behavior is shown to be
strongly dependent on geometric properties such as cell alignment and cell
shape. Using a perturbative method under the assumption of weak coupling
between cells, we derive a reduced model in which each cell is described by
just one variable, the phase. The reduced model resembles an XY model but
contains novel terms that possesses geometric information, which enables the
understanding of the geometric dependencies as well as the effects of external
signal and noise. The model is simple, generic, and analytically and
numerically tractable, and is therefore expected to facilitates studies on
cellular polarity alignment in various nonequilibrium systems.


title: Trace reconstruction with $\exp( O( n^{1/3} ) )$ samples

abstract:
  In the trace reconstruction problem, an unknown bit string $x \in \{0,1\}^n$
is observed through the deletion channel, which deletes each bit of $x$ with
some constant probability $q$, yielding a contracted string $\widetilde{x}$.
How many independent copies of $\widetilde{x}$ are needed to reconstruct $x$
with high probability? Prior to this work, the best upper bound, due to
Holenstein, Mitzenmacher, Panigrahy, and Wieder (2008), was
$\exp(\widetilde{O}(n^{1/2}))$. We improve this bound to $\exp(O(n^{1/3}))$
using statistics of individual bits in the output and show that this bound is
sharp in the restricted model where this is the only information used. Our
method, that uses elementary complex analysis, can also handle insertions.


title: Quaternionic toric manifolds

abstract:
  In the present paper we introduce and study a new notion of toric manifold in
the quaternionic setting. We develop a construction with which, starting from
appropriate $m$-dimensional Delzant polytopes, we obtain manifolds of real
dimension $4m$, acted on by $m$ copies of the group ${\rm Sp}(1)$ of unit
quaternions. These manifolds are quaternionic regular and can be endowed with a
$4$-plectic structure and a generalized moment map. Convexity properties of the
image of the moment map are studied. Quaternionic toric manifolds appear to be
a large enough class of examples where one can test and study new results in
quaternionic geometry.


title: Matrix product ansatz for non-equilibrium quantum steady states

abstract:
  We present a general construction of matrix product states for stationary
density matrices of one-dimensional quantum spin systems kept out of
equilibrium through boundary Lindblad dynamics. As an application we review the
isotropic Heisenberg quantum spin chain which is closely related to the
generator of the simple symmetric exclusion process. Exact and heuristic
results as well as numerical evidence suggest a local quantum equilibrium and
long-range correlations reminiscent of similar large-scale properties in
classical stochastic interacting particle systems that can be understood in
terms of fluctuating hydrodynamics.


title:
High-Visibility Time-Bin Entanglement for Testing Chained Bell
  Inequalities

abstract:
  The violation of Bell's inequality requires a well-designed experiment to
validate the result. In experiments using energy-time and time-bin
entanglement, initially proposed by Franson in 1989, there is an intrinsic
loophole due to the high postselection. To obtain a violation in this type of
experiment, a chained Bell inequality must be used. However, the local realism
bound requires a high visibility in excess of 94.63 percent in the time-bin
entangled state. In this work, we show how such a high visibility can be
reached in order to violate a chained Bell inequality with 6, 8 and 10 terms.


title:
Radially anisotropic systems with $r^{-\alpha}$ forces. II: radial-orbit
  instability

abstract:
  We continue to investigate the dynamics of collisionless systems of particles
interacting via additive $r^{-\alpha}$ interparticle forces. Here we focus on
the dependence of the radial-orbit instability on the force exponent $\alpha$.
By means of direct $N$-body simulations we study the stability of equilibrium
radially anisotropic Osipkov-Merritt spherical models with Hernquist density
profile and with $1\leq\alpha<3$. We determine, as a function of $\alpha$, the
minimum value for stability of the anisotropy radius $r_{as}$ and of the
maximum value of the associated stability indicator $\xi_s$. We find that, for
decreasing $\alpha$, $r_{as}$ decreases and $\xi_s$ increases, i.e.
longer-range forces are more robust against radial-orbit instability. The
isotropic systems are found to be stable for all the explored values of
$\alpha$. The end products of unstable systems are all markedly triaxial with
minor-to-major axial ratio $>0.3$, so they are never flatter than an E7 system.


title:
Example of an inhomogeneous cosmological model in the context of
  backreaction

abstract:
  In this article, we present an example of an inhomogeneous cosmological
model, which is inspired by the linear perturbation theory. The metric of this
model can be described as the Einstein-de Sitter background with a periodically
distributed dust overdensities. The model construction enables application of
the Green-Wald averaging scheme and the Buchert averaging technique
simultaneously. We compare the angular diameter distance function of the
considered model to the angular diameter distances corresponding to the average
space-times given by the Green-Wald and the Buchert frameworks respectively.


title: Performance of the LBNL FastCCD for the European XFEL

abstract:
  The European X-ray Free Electron Laser (XFEL.EU) is currently being
commissioned in Schenefeld, Germany. From 2017 onwards it will provide
spatially coherent X-rays of energies between 0.25\,keV and 25\,keV with a
unique timing structure. One of the detectors foreseen at XFEL.EU for the soft
X-ray regime (energies below 6\,keV) is a quasi column-parallel readout FastCCD
developed by Lawrence Berkeley National Lab (LBNL) specifically for the XFEL.EU
requirements. Its sensor has 1920$\times$960 pixels of 30\,$\mu$m
$\times$30\,$\mu$m size with a beam hole in the middle of the sensor. The
camera can be operated in full frame and frame store mode. With the FastCCD a
frame rate of up to 120~fps can be achieved, but at XFEL.EU the camera settings
are optimized for the 10\,Hz XFEL bunch-mode. The detector has been delivered
to XFEL.EU. Results of the performance tests and calibration done using the
XFEL.EU detector calibration infrastructure are presented quantifying noise
level, gain and energy resolution.


title: Analysis of Wigner's Set Theoretical Proof for Bell-type inequalities

abstract:
  We present a detailed analysis of the set theoretical proof of Wigner for
Bell type inequalities with the following result. Wigner introduced a crucial
assumption that is not related to Einstein's local realism, but instead,
without justification, to the existence of certain joint probability measures
for possible and actual measurement outcomes of Einstein-Podolsky-Rosen (EPR)
experiments. His conclusions about Einstein's local realism are, therefore, not
applicable to EPR experiments and the contradiction of the experimental
outcomes to Wigner's results has no bearing on the validity of Einstein's local
realism.


title: $k$-Distinct In- and Out-Branchings in Digraphs

abstract:
  An out-branching and an in-branching of a digraph $D$ are called $k$-distinct
if each of them has $k$ arcs absent in the other. Bang-Jensen, Saurabh and
Simonsen (2016) proved that the problem of deciding whether a strongly
connected digraph $D$ has $k$-distinct out-branching and in-branching is
fixed-parameter tractable (FPT) when parameterized by $k$. They asked whether
the problem remains FPT when extended to arbitrary digraphs. Bang-Jensen and
Yeo (2008) asked whether the same problem is FPT when the out-branching and
in-branching have the same root. By linking the two problems with the problem
of whether a digraph has an out-branching with at least $k$ leaves (a leaf is a
vertex of out-degree zero), we first solve the problem of Bang-Jensen and Yeo
(2008). We then develop a new digraph decomposition called the rooted cut
decomposition and using it we prove that the problem of Bang-Jensen et al.
(2016) is FPT for all digraphs. We believe that the \emph{rooted cut
decomposition} will be useful for obtaining other results on digraphs.


title: A one-way ANOVA test for functional data with graphical interpretation

abstract:
  A new functional ANOVA test, with a graphical interpretation of the result,
is presented. The test is an extension of the global envelope test introduced
by Myllymaki et al. (2017, Global envelope tests for spatial processes, J. R.
Statist. Soc. B 79, 381--404, doi: 10.1111/rssb.12172). The graphical
interpretation is realized by a global envelope which is drawn jointly for all
samples of functions. If a mean function computed from the empirical data is
out of the given envelope, the null hypothesis is rejected with the
predetermined significance level $\alpha$. The advantages of the proposed
one-way functional ANOVA are that it identifies the domains of the functions
which are responsible for the potential rejection. We introduce two versions of
this test: the first gives a graphical interpretation of the test results in
the original space of the functions and the second immediately offers a
post-hoc test by identifying the significant pair-wise differences between
groups. The proposed tests rely on discretization of the functions, therefore
the tests are also applicable in the multidimensional ANOVA problem. In the
empirical part of the article, we demonstrate the use of the method by
analyzing fiscal decentralization in European countries. The aim of the
empirical analysis is to capture differences between the levels of government
expenditure decentralization ratio among different groups of European
countries. The idea behind, based on the existing literature, is
straightforward: countries with a longer European integration history are
supposed to decentralize more of their government expenditure. We use the
government expenditure centralization ratios of 29 European Union and EFTA
countries in period from 1995 to 2016 sorted into three groups according to the
presumed level of European economic and political integration.


title:
Synthesis and properties of A$_x$V$_2$Al$_{20}$ (A = Th, U, Np, Pu)
  ternary actinide aluminides

abstract:
  Polycrystalline samples of A$_x$V$_2$Al$_{20}$ (A = Ce, Th, U, Np, Pu; 0.7 =<
x =< 1.0) actinide intermetallics were synthesized using the arc-melting
method. Crystal structure studies were performed by means of powder x-ray
diffraction and the Rietveld refinement method. All studied compounds
crystallize in the CeCr$_{2}$Al$_{20}$-type structure (space group Fd-3m, no.
227) with the actinide or Ce atom located in the oversized cage formed by Al
atoms. Comparison of the crystallographic results with the reported data for
LnV$_{2}$Al$_{20}$ (Ln = lanthanoids) counterparts reveals distinctly different
behavior of the lanthanide- and actinide-bearing compounds. This difference is
suggested to be caused by fairly localized character of the 4f electrons,
whereas itinerant character of the 5f electrons is likely seen for U- and
Np-containing phases. Magnetic susceptibility and specific heat measurements
did not reveal any magnetic ordering in U$_{0.8}$V$_{2}$Al$_{20}$,
Np$_{0.8}$V$_{2}$Al$_{20}$ and Pu$_{0.8}$V$_{2}$Al$_{20}$ down to 2.5 K. A
small anomaly in low-temperature specific heat of Ce$_{0.8}$V$_{2}$Al$_{20}$,
U$_{0.8}$V$_{2}$Al$_{20}$, and Np$_{0.8}$V$_{2}$Al$_{20}$ is observed, likely
arising from a low-energy Einstein mode.


title: Topologically nontrivial electronic states in CaSn$_{3}$

abstract:
  Based on the first-principles calculations, we theoretically propose
topologically non-trivial states in a recently experimentally discovered
superconducting material CaSn$_3$. When the spin-orbit coupling (SOC) is
ignored, the material is a host to three-dimensional topological nodal-line
semimetal states. Drumhead like surface states protected by the coexistence of
time-reversal and mirror symmetry emerge within the two-dimensional regions of
the surface Brillouin zone connecting the nodal lines. When SOC is included,
unexpectedly, each nodal line evolves into two Weyl nodes (W1, W2) in this
centrosymmetric material. Berry curvature calculations show that these nodes
occur in a pair and act as either a source or sink of Berry flux. The material
also has unique surface states in the form of Fermi arcs, which unlike other
known Weyl semimetal, form closed loops of surface states on the Fermi surface.
Our theoretical realization of topologically non-trivial states in a
superconducting material paves the way towards unraveling the interconnection
between topological physics and superconductivity.


title: Neutrino Processes with Hot Nuclei in Supernovae

abstract:
  In this paper, we calculate cross sections for charged-current
neutrino-nucleus processes occuring under presupernova conditions. To treat
thermal effects we extend self-consistent Skyrme-QRPA calculations to finite
temperature by using the formalism of thermo field dynamics. The numerical
results are presented for the sample nuclei, $^{56}$Fe and $^{82}$Ge


title: Gravitationally induced phase shift on a single photon

abstract:
  The effect of the Earth's gravitational potential on a quantum wave function
has only been observed for massive particles. In this paper we present a scheme
to measure a gravitationally induced phase shift on a single photon travelling
in a coherent superposition along different paths of an optical fiber
interferometer. To create a measurable signal for the interaction between the
static gravitational potential and the wave function of the photon, we propose
a variant of a conventional Mach-Zehnder interferometer. We show that the
predicted relative phase difference of $10^{-5}$ radians is measurable even in
the presence of fiber noise, provided additional stabilization techniques are
implemented for each arm of a large-scale fiber interferometer. Effects arising
from the rotation of the Earth and the material properties of the fibers are
analysed. We conclude that optical fiber interferometry is a feasible way to
measure the gravitationally induced phase shift on a single-photon wave
function, and thus provides a means to corroborate the equivalence of the
energy of the photon and its effective gravitational mass.


title:
Generation of a non-zero discord bipartite state with classical
  second-order interference

abstract:
  We report investigation on quantum discord in classical second-order
interference. In particular, we theoretically show that a bipartite state with
D = 0.311 of discord can be generated via classical second-order interference.
We also experimentally verify the theory by obtaining D = 0.197 +- 0.060 of
non-zero discord state. Together with the fact that non-classicalities
originated from physical constraints and information theoretic perspectives are
not equivalent, this result provides an insight to understand the nature of
quantum discord.


title: Increasing Launch Efficiency with the PEGASUS Launcher

abstract:
  In the real world application of railguns, the launch efficiency is one of
the most important parameters. This efficiency directly relates to the capacity
of the electrical energy storage that is needed for the launch. In this study,
the rail/armature contact behavior for two different armature technologies was
compared. To this end, experiments using aluminum c-shaped armature and copper
brush armature type projectiles were performed under same initial conditions.
The c-shaped armature type showed a superior behavior with respect to
electrical contact to the rails and in acceleration. A 300 g projectile with a
c-shaped armature reached a velocity of 3100 m/s and an overall launch
efficiency including the power supply of 41%. This is to be compared to 2500
m/s and 23% for the launching of a projectile using a brush armature.


title: Kernel-based Reconstruction of Space-time Functions on Dynamic Graphs

abstract:
  Graph-based methods pervade the inference toolkits of numerous disciplines
including sociology, biology, neuroscience, physics, chemistry, and
engineering. A challenging problem encountered in this context pertains to
determining the attributes of a set of vertices given those of another subset
at possibly different time instants. Leveraging spatiotemporal dynamics can
drastically reduce the number of observed vertices, and hence the cost of
sampling. Alleviating the limited flexibility of existing approaches, the
present paper broadens the existing kernel-based graph function reconstruction
framework to accommodate time-evolving functions over possibly time-evolving
topologies. This approach inherits the versatility and generality of
kernel-based methods, for which no knowledge on distributions or second-order
statistics is required. Systematic guidelines are provided to construct two
families of space-time kernels with complementary strengths. The first
facilitates judicious control of regularization on a space-time frequency
plane, whereas the second can afford time-varying topologies. Batch and online
estimators are also put forth, and a novel kernel Kalman filter is developed to
obtain these estimates at affordable computational cost. Numerical tests with
real data sets corroborate the merits of the proposed methods relative to
competing alternatives.


title:
Propagation of intense few-cycle laser pulse in a telecommunication-type
  optical fiber: analysis of the error introduced by the unidirectional
  approximation

abstract:
  Propagation of few-cycle laser pulses in optical fiber is investigated beyond
the unidirectional approximation. Considered medium parameters include
dispersion, Kerr and Raman nonlinearities. High intensities of ~10^10 kW/cm^2
lead to generation of the octave-spanning continuum. The error of the
unidirectional approximation is seen in simulations as two pulses propagating
forwards and backwards, both remain weak under the considered conditions.
Direct analytical estimate of the error is derived and verified numerically. It
can be applied to a priory justification of the unidirectional approach.


title:
Bogoliubov theory of interacting bosons: new insights from an old
  problem

abstract:
  In a gas of $N$ interacting bosons, the Hamiltonian $H_c$, obtained by
dropping all the interaction terms between free bosons with moment
$\hbar\mathbf{k}\ne\mathbf{0}$, is diagonalized exactly. The resulting
eigenstates $|\:S,\:\mathbf{k},\:\eta\:\rangle$ depend on two discrete indices
$S,\:\eta=0,\:1,\:\dots$, where $\eta$ numerates the \emph{quasiphonons}
carrying a moment $\hbar\mathbf{k}$, responsible for transport or dissipation
processes. $S$, in turn, numerates a ladder of \textquoteleft
vacua\textquoteright$\:|\:S,\:\mathbf{k},\:0\:\rangle$, with increasing
equispaced energies, formed by boson pairs with opposite moment. Passing from
one vacuum to another ($S\rightarrow S\pm1$), results from
creation/annihilation of new momentless collective excitations, that we call
\emph{vacuons}. Exact quasiphonons originate from one of the vacua by
\textquoteleft creating\textquoteright$\:$an asymmetry in the number of
opposite moment bosons. The well known Bogoliubov collective excitations (CEs)
are shown to coincide with the exact eigenstates
$|\:0,\:\mathbf{k},\:\eta\:\rangle$, i.e. with the quasiphonons created from
the lowest-level vacuum ($S=0$). All this is discussed, in view of existing or
future experimental observations of the vacuons (PBs), a sort of bosonic Cooper
pairs, which are the main factor of novelty beyond Bogoliubov theory.


title: Generating Code Summaries Using the Power of the Crowd

abstract:
  One of the first steps to perform most of the software maintenance
activities, such as updating features or fixing bugs, is to have a relatively
good understanding of the program's source code which is often written by other
developers. A code summary is a description about a program's entities (e.g.,
its methods) which helps developers have a better comprehension of the code in
a shorter period of time. However, generating code summaries can be a
challenging task. To mitigate this problem, in this article, we introduce
CrowdSummarizer, a code summarization platform that benefits from the concepts
of crowdsourcing, gamification, and natural language processing to
automatically generate a high level summary for the methods of a Java program.
We have implemented CrowdSummarizer as an Eclipse plugin together with a
web-based code summarization game that can be played by the crowd. The results
of two empirical studies that evaluate the applicability of the approach and
the quality of generated summaries indicate that CrowdSummarizer is effective
in generating quality results.


title:
Impurity bound states in fully gapped $d$-wave superconductors with
  subdominant order parameters

abstract:
  Impurities in superconductors and their induced bound states are important
both for engineering novel states such as Majorana zero-energy modes and for
probing bulk properties of the superconducting state. The high-temperature
cuprates offer a clear advantage in a much larger superconducting order
parameter, but the nodal energy spectrum of a pure $d$-wave superconductor only
allows virtual bound states. Fully gapped $d$-wave superconducting states have
however been proposed in several cuprate systems thanks to subdominant order
parameters producing $d+is$- or $d+id'$-wave superconducting states. Here we
study both magnetic and potential impurities in these fully gapped $d$-wave
superconductors. Using analytical T-matrix and complementary numerical
tight-binding lattice calculations, we show that magnetic and potential
impurities behave fundamentally different in $d+is$- and $d+id'$-wave
superconductors. In a $d+is$-wave superconductor, there are no bound states for
potential impurities, while a magnetic impurity produces one pair of bound
states, with a zero-energy level crossing at a finite scattering strength. On
the other hand, a $d+id'$-wave symmetry always give rise to two pairs of bound
states and only produce a reachable zero-energy level crossing if the normal
state has a strong particle-hole asymmetry.


title:
Hamiltonian cycles for the square of the augmentation graphs and Gray
  codes for restricted permutations and ascent sequences

abstract:
  In this paper, we construct a listing for the vertices of the augmentation
graph of given size, and as a consequence, we obtain a Hamiltonian cycle for
the square of the augmentation graph of given size. As applications, we have a
Gray code for the $132$-$312$ avoiding permutations of given length such that
two successive permutations differ by at most $2$ adjacent transpositions. Also
we obtain Gray codes of strong distance $2$ for the $001$ avoiding ascent
sequences and the $010$ avoiding ascent sequences of given length.


title: Quantum-enhanced multi-parameter estimation for unitary photonic systems

abstract:
  Precise device characterization is a fundamental requirement for a large
range of applications using photonic hardware, and constitutes a
multi-parameter estimation problem. Estimates based on measurements using
single photons or classical light have precision which is limited by
shot-noise, while quantum resources can be used to achieve sub-shot-noise
precision. However, there are many open questions with regard to the best
quantum protocols for multi-parameter estimation, including the ultimate limits
to achievable precision, as well as optimal choices for probe states and
measurements. In this paper, we develop a formalism based on Fisher information
to tackle these questions for set-ups based on linear-optical components and
photon-counting measurements. A key ingredient of our analysis is a mapping for
equivalent protocols defined for photonic and spin systems, which allows us to
draw upon results in the literature for general finite-dimensional systems.
Motivated by the protocol in X.-Q. Zhou, et al., Optica 2, 510 (2015), we
present new results for quantum-enhanced tomography of unitary processes,
including a comparison of Holland-Burnett and NOON probe states.


title: A new Improvement of Ambarzumyan's Theorem

abstract:
  We extend the classical Ambarzumyan's theorem to the quasi-periodic boundary
value problems by using only a part knowledge of one spectrum. We also weaken
slightly the Yurko's conditions on the first eigenvalue.


title: Homogeneous distributions on finite dimensional vector spaces

abstract:
  Let $V$ be a finite dimensional vector space over a local field $F$. Let
$\chi: F^\times \rightarrow \mathbb C^\times$ be an arbitrary character of
$F^\times$. We determine the structure of the natural representation of
$\mathrm{GL}(V)$ on the space $\mathcal{S}^*(V)^\chi$ of $\chi$-invariant
distributions on $V$.


title: Lie's correspondence for commutative automorphic formal loops

abstract:
  We develop Lie's correspondence and an explicit Baker-Campbell-Hausdorff
formula for commutative automorphic formal loops.


title:
Problems to be clarified by means of redioactive ion beams provided by
  the ACCULINNA-2 separator

abstract:
  Fragment separator ACCULINNA-2 has been built in the Flerov Laboratory of
Nuclear reactions (JINR, Dubna). It is timely now to choose meaningful and
challenging objectives for experiments dedicated to the study of light
drip-line nuclei. Considerable interest makes the search for the minor
$2p$-decay branch of the first excited state of $^{17}$Ne. The knowledge on the
$\Gamma_{2p}/\Gamma_{\gamma}$ width ratio for this excited state is of
considerable interest because the reverse process of simultaneous two-proton
radiative capture could be a bypass for the $^{15}$O "waiting point" occurring
in the rp-process of nucleosynthesis. Accumulation of high-statistics data for
the $^{10}$He excitation spectrum populated in the $^2$H($^8$He,$p$)$^9$He and
$^3$H($^8$He,$p$)$^{10}$He reactions, as well as the study of cross-check
reactions made with the $^{11}$Li and $^{14}$Be beams, will make an effective
way to clarify the succession of $^{10}$He excited states. A hot topic beyond
the neutron drip line makes the observation of results capable to elucidate the
low-energy resonance states anticipated for the $4n$ decay of $^{7}$H. The RIB
beams provided by ACCULINNA-2 will allow one to perform experiments where
luminosity coming to a level of more than $2 \times 10^{26}$ cm$^{-2}$ s$^{-1}$
will be achievable in experiments aimed study of the $^2$H($^8$He,$^3$He)$^7$H
and $^2$H($^{11}$Li,$^6$Li)$^7$H reactions.


title:
Simulating Electromagnetic Cascades in Magnetospheres of Active Galactic
  Nuclei

abstract:
  Context: At the low accretion-rates typical for BL Lac-objects,
magnetospheres of active galactic nuclei can develop vacuum gaps with strong
electric fields accelerating charged seed particles parallel to the magnetic
fields up to ultra-relativistic energies. The seed particles sustain
electromagnetic cascades by inverse-Compton-scattering and subsequent
pair-production in soft background-radiation-fields from the accretion-disk
and/or photo-ionised clouds, along the direction of the primary particle beams.
  Method: The one-dimensional kinetic equation describing this linear
inverse-Compton-Klein-Nishina-pair-cascade is inferred. We have developed a
novel code, that can numerically solve this kinetic equation for an ample
variety of input-parameters. By this, quasi-stationary particle- and
photon-spectra are obtained.
  Application: We use the code to model the cascaded interaction of electrons,
that have been accelerated in a vacuum gap in the magnetosphere of Mrk 501,
with Lyman-alpha-photons. The resulting spectrum on top of a
synchrotron-self-Compton-background can cause a narrow TeV-bump in the spectrum
of Mrk 501.


title: Holographic complexity and action growth in massive gravities

abstract:
  In this paper, we investigate the growth rates of action for the anti-de
Sitter black holes in massive-Einstein gravity models and obtain the universal
behaviors of the growth rates of action (the rates of holographic complexity)
within the "Wheeler-DeWitt"(WDW) patch at the late limit. Furthermore, we find
that, for the static neutral cases, when the same mass of black holes is given,
the computational speed of the neutral massive black hole is the same as its
Einstein gravity counterpart, which is independent with the effect of the
graviton mass terms, nevertheless, for the static charged cases, when the same
mass and charge parameters of black holes are given, the growth rates of action
for the massive charged black holes are always superior to the growth rates of
action without graviton mass terms, which directly shows that the massive
charged black holes as computers on the computational speeds are faster than
their Einstein gravity counterparts.


title:
VIBIKNet: Visual Bidirectional Kernelized Network for Visual Question
  Answering

abstract:
  In this paper, we address the problem of visual question answering by
proposing a novel model, called VIBIKNet. Our model is based on integrating
Kernelized Convolutional Neural Networks and Long-Short Term Memory units to
generate an answer given a question about an image. We prove that VIBIKNet is
an optimal trade-off between accuracy and computational load, in terms of
memory and time consumption. We validate our method on the VQA challenge
dataset and compare it to the top performing methods in order to illustrate its
performance and speed.


title: CP violation and BSM Higgs bosons

abstract:
  We study extensions of the Standard Model (SM) in which copies of the SM
scalar SU(2) doublet are added to the Higgs sector. These scalar doublets
either acquire a Vacuum Expectation Value (VEV) and hence are active or do not
develop a VEV and are inert. We consider CP-violation (CPV) in both the active
and inert sector. As an example of a model with CPV in the active sector, we
present a Type-I 2-Higgs-Doublet Model (2HDM) with two active doublets and show
Large Hadron Collider (LHC) signals of such a scenario. The amount of CPV in
this case is very limited due to constraints coming from Electric Dipole Moment
experiments. Moreover, 2HDMs with only active doublets do not provide a Dark
Matter (DM) candidate. As a result, we turn to 3-Higgs-Doublet Models (3HDMs)
where unbounded CPV and viable DM candidates could be introduced simultaneously
in the inert sector. We investigate DM phenomenology of such models.


title:
A Binary Convolutional Encoder-decoder Network for Real-time Natural
  Scene Text Processing

abstract:
  In this paper, we develop a binary convolutional encoder-decoder network
(B-CEDNet) for natural scene text processing (NSTP). It converts a text image
to a class-distinguished salience map that reveals the categorical, spatial and
morphological information of characters. The existing solutions are either
memory consuming or run-time consuming that cannot be applied to real-time
applications on resource-constrained devices such as advanced driver assistance
systems. The developed network can process multiple regions containing
characters by one-off forward operation, and is trained to have binary weights
and binary feature maps, which lead to both remarkable inference run-time
speedup and memory usage reduction. By training with over 200, 000 synthesis
scene text images (size of $32\times128$), it can achieve $90\%$ and $91\%$
pixel-wise accuracy on ICDAR-03 and ICDAR-13 datasets. It only consumes $4.59\
ms$ inference run-time realized on GPU with a small network size of 2.14 MB,
which is up to $8\times$ faster and $96\%$ smaller than it full-precision
version.


title: Static Elliptic Minimal Surfaces in AdS(4)

abstract:
  The Ryu-Takayanagi conjecture connects the entanglement entropy in the
boundary CFT to the area of open co-dimension two minimal surfaces in the bulk.
Especially in AdS(4), the latter are two-dimensional surfaces, and, thus,
solutions of a Euclidean non-linear sigma model on a symmetric target space
that can be reduced to an integrable system via Pohlmeyer reduction. In this
work, we invert Pohlmeyer reduction to construct static minimal surfaces in
AdS(4) that correspond to elliptic solutions of the reduced system, namely the
cosh-Gordon equation. The constructed minimal surfaces comprise a two-parameter
family of surfaces that include helicoids and catenoids in H(3) as special
limits. Minimal surfaces that correspond to identical boundary conditions are
discovered within the constructed family of surfaces and the relevant geometric
phase transitions are studied.


title:
Ap stars with resolved magnetically split lines: Magnetic field
  determinations from Stokes $I$ and $V$ spectra

abstract:
  We present the results of a systematic study of the magnetic fields and other
properties of the Ap stars with resolved magnetically split lines. This study
is based on new measurements of the mean magnetic field modulus, the mean
longitudinal magnetic field, the crossover, the mean quadratic magnetic field,
and the radial velocity of 43 stars, complemented by magnetic data from the
literature for 41 additional stars. Stars with resolved magnetically split
lines represent a significant fraction, of the order of several percent, of the
whole population of Ap stars. Most of them are genuine slow rotators, whose
consideration provides new insight into the long-period tail of the
distribution of the periods of the Ap stars. Emerging correlations between
rotation periods and magnetic properties provide important clues for the
understanding of the braking mechanisms that have been at play in the early
stages of stellar evolution. The geometrical structures of the magnetic fields
of Ap stars with magnetically resolved lines appear in general to depart
slightly, but not extremely, from centred dipoles. However, there are a few
remarkable exceptions, which deserve further consideration. We suggest that
pulsational crossover can be observed in some stars; if confirmed, this would
open the door to the study of non-radial pulsation modes of degree $\ell$ too
high for photometric or spectroscopic observations. How the lack of short
orbital periods among binaries containing an Ap component with magnetically
resolved lines is related with their (extremely) slow rotation remains to be
fully understood, but the very existence of acorrelation between the two
periods lends support to the merger scenario for the origin of Ap stars.


title: The abundance discrepancy in H II regions

abstract:
  In this paper we discuss some results concerning the abundance discrepancy
problem in the context of H II regions. We discuss the behavior of the
abundance discrepancy factor (ADF) for different objects and ions. There are
evidences that stellar abundances seem to agree better with the nebular ones
derived from recombination lines in high-metallicity environments and from
collisionally excited lines in the low-metallicity regime. Recent data point
out that the ADF seems to be correlated with the metallicity and the electron
temperature of the objects. These results open new ways for investigating the
origin of the abundance discrepancy problem in H II regions and in ionized
nebulae in general.


title: Commutative algebraic groups up to isogeny. II

abstract:
  This paper develops a representation-theoretic approach to the isogeny
category $\underline{\mathcal{C}}$ of commutative group schemes of finite type
over a field $k$, studied in arXiv:1602:00222. We construct a ring $R$ such
that $\underline{\mathcal{C}}$ is equivalent to the category $R$-mod of all
left $R$-modules of finite length. We also construct an abelian category of
$R$-modules, $R$-$\widetilde{\rm mod}$, which is hereditary, has enough
projectives, and contains $R$-mod as a Serre subcategory; this yields a more
conceptual proof of the main result of [loc. cit.], asserting that
$\underline{\mathcal{C}}$ is hereditary. We show that $R$-$\widetilde{\rm mod}$
is equivalent to the isogeny category of commutative quasi-compact $k$-group
schemes.


title: First operation of a harmonic lasing self-seeded free electron laser

abstract:
  Harmonic lasing is a perspective mode of operation of X-ray FEL user
facilities that allows to provide brilliant beams of higher energy photons for
user experiments. Another useful application of harmonic lasing is so called
Harmonic Lasing Self-Seeded Free Electron Laser (HLSS FEL) that allows to
improve spectral brightness of these facilities. In the past, harmonic lasing
has been demonstrated in the FEL oscillators in infrared and visible wavelength
ranges, but not in high-gain FELs and not at short wavelengths. In this paper
we report on the first evidence of the harmonic lasing and the first operation
of the HLSS FEL at the soft X-ray FEL user facility FLASH in the wavelength
range between 4.5 nm and 15 nm. Spectral brightness was improved in comparison
with Self-Amplified Spontaneous emission (SASE) FEL by a factor of six in the
exponential gain regime. A better performance of HLSS FEL with respect to SASE
FEL in the post-saturation regime with a tapered undulator was observed as
well. The first demonstration of harmonic lasing in a high-gain FEL and at
short wavelengths paves the way for a variety of applications of this new
operation mode in X-ray FELs.


title:
Measurements of top-quark pair to $Z$-boson cross-section ratios at
  $\sqrt s = 13, 8, 7$TeV with the ATLAS detector

abstract:
  Ratios of top-quark pair to $Z$-boson cross sections measured from
proton--proton collisions at the LHC centre-of-mass energies of $\sqrt
s=13$TeV, 8TeV, and 7TeV are presented by the ATLAS Collaboration. Single
ratios, at a given $\sqrt s$ for the two processes and at different $\sqrt s$
for each process, as well as double ratios of the two processes at different
$\sqrt s$, are evaluated. The ratios are constructed using previously published
ATLAS measurements of the $t\overline{t}$ and $Z$-boson production cross
sections, corrected to a common phase space where required, and a new analysis
of $Z \rightarrow \ell^+ \ell^-$ where $\ell=e,\mu$ at $\sqrt s=13$TeV
performed with data collected in 2015 with an integrated luminosity of
$3.2$fb$^{-1}$. Correlations of systematic uncertainties are taken into account
when evaluating the uncertainties in the ratios. The correlation model is also
used to evaluate the combined cross section of the $Z\rightarrow e^+e^-$ and
the $Z\rightarrow \mu^+ \mu^-$ channels for each $\sqrt s$ value. The results
are compared to calculations performed at next-to-next-to-leading-order
accuracy using recent sets of parton distribution functions. The data
demonstrate significant power to constrain the gluon distribution function for
the Bjorken-$x$ values near 0.1 and the light-quark sea for $x<0.02$.


title:
Unidirectional scattering induced by the toroidal dipole moment in the
  system of plasmonic nanoparticles

abstract:
  Unidirectional backward and forward scattering of electromagnetic waves by
nanoparticles are usually interpreted as the interference of conventional
multipole moments (i.e., electric and magnetic dipole, electric quadrupole,
etc.). The role of toroidal dipole moments in unidirectional scattering is
generally overlooked. In this work, we investigate the unidirectional
scattering for the system of three plasmonic nanospheres. It is found that the
unidirectional backward scattering is caused by the interference between the
toroidal dipole moment and other conventional multipole moments. Tunable
primary backward and forward scattering can be achieved under some specific
configurations. Our results can find applications in the design of
nanoantennas.


title: Intersection Graphs of Rays and Grounded Segments

abstract:
  We consider several classes of intersection graphs of line segments in the
plane and prove new equality and separation results between those classes. In
particular, we show that: (1) intersection graphs of grounded segments and
intersection graphs of downward rays form the same graph class, (2) not every
intersection graph of rays is an intersection graph of downward rays, and (3)
not every intersection graph of rays is an outer segment graph. The first
result answers an open problem posed by Cabello and Jej\v{c}i\v{c}. The third
result confirms a conjecture by Cabello. We thereby completely elucidate the
remaining open questions on the containment relations between these classes of
segment graphs. We further characterize the complexity of the recognition
problems for the classes of outer segment, grounded segment, and ray
intersection graphs. We prove that these recognition problems are complete for
the existential theory of the reals. This holds even if a 1-string realization
is given as additional input.


title:
Connection Discovery using Shared Images by Gaussian Relational Topic
  Model

abstract:
  Social graphs, representing online friendships among users, are one of the
fundamental types of data for many applications, such as recommendation,
virality prediction and marketing in social media. However, this data may be
unavailable due to the privacy concerns of users, or kept private by social
network operators, which makes such applications difficult. Inferring user
interests and discovering user connections through their shared multimedia
content has attracted more and more attention in recent years. This paper
proposes a Gaussian relational topic model for connection discovery using user
shared images in social media. The proposed model not only models user
interests as latent variables through their shared images, but also considers
the connections between users as a result of their shared images. It explicitly
relates user shared images to user connections in a hierarchical, systematic
and supervisory way and provides an end-to-end solution for the problem. This
paper also derives efficient variational inference and learning algorithms for
the posterior of the latent variables and model parameters. It is demonstrated
through experiments with over 200k images from Flickr that the proposed method
significantly outperforms the methods in previous works.


title:
Toward improving the visual stimulus meaning for increasing the P300
  detection

abstract:
  The P300 speller is a well known Brain-Computer Interface paradigm that has
been used for over two decades. A new P300 speller paradigm (XP300) is
proposed. It includes several characteristics: (i) the items are not
intensified by using rows and columns, (ii) the order of the visual stimuli is
pseudo-random, (iii) a visual feedback is added on each item to increase the
stimulus meaning, which is the main novelty. XP300 has been tested on ten
healthy subjects on copy spelling mode, with only eight sensors. It has been
compared with the classical P300 paradigm (CP300). With five repetitions, the
average recognition rate across subjects is 85.25% for XP300 and 77.25% for
CP300. Single-trial detection is significantly higher with XP300 by comparing
the AUC (Area Under Curve) of the ROC (Receiver Operating Characteristic)
curve. The mean AUC is 0.86 for XP300, 0.80 for CP300. More importantly, XP300
has also been judged as more convenient and user-friendly than CP300, hence
being able to allow longer sessions.


title: Developing Security Reputation Metrics for Hosting Providers

abstract:
  Research into cybercrime often points to concentrations of abuse at certain
hosting providers. The implication is that these providers are worse in terms
of security; some are considered `bad' or even `bullet proof'. Remarkably
little work exists on systematically comparing the security performance of
providers. Existing metrics typically count instances of abuse and sometimes
normalize these counts by taking into account the advertised address space of
the provider. None of these attempts have worked through the serious
methodological challenges that plague metric design. In this paper we present a
systematic approach for metrics development and identify the main challenges:
(i) identification of providers, (ii) abuse data coverage and quality, (iii)
normalization, (iv) aggregation and (v) metric interpretation. We describe a
pragmatic approach to deal with these challenges. In the process, we answer an
urgent question posed to us by the Dutch police: `which are the worst providers
in our jurisdiction?'. Notwithstanding their limitations, there is a clear need
for security metrics for hosting providers in the fight against cybercrime.


title: Safety-Interlock System of the DSSC X-Ray Imager

abstract:
  In this paper, the DSSC safety-interlock system is introduced. It is designed
to keep the DSSC mega-pixel camera in a safe-state. The system is composed of
four inter-communicating sub-systems referred here as a master SIB
(safety-interlock board) and three partner SIBs. Each SIB monitors and
processes 75 temperature sensors mainly located in the focal plane and also
distributed inside the camera-head electronics. It monitors the signals from
two pressure sensors, one humidity sensor as well as the connectivity to
sixteen low-voltage and two high-voltage cables. The master SIB supervises the
signals to and from external equipments like the cooling system, pressure
gauge, power crates and status information from experimental environment. SIB
is an 8-layer printed-circuit board (PCB) with a micro-controller sitting on
top as its central processing unit. A decision-matrix software reads the sensor
status continuously and determines whether the camera is in a safe state or
not. All error and warnings flags are sent to the detector control software
framework and the end user directly. These flags are also stored every 100 ms
together with the image data. The full SIB sensor data is sent to the back end
for offline analysis. A shutdown sequence is initiated by SIB in case of a
critical failure. The safety-interlock philosophy, hardware design, and
software architecture along with test results will be presented.


title: Almost duality for Saito structure and complex reflection groups

abstract:
  We reformulate Dubrovin's almost duality of Frobenius structures to Saito
structures without metric. Then we formulate and study the existence and
uniqueness problem of the natural Saito structure on the orbit spaces of finite
complex reflection groups from the viewpoint of the almost duality. We give a
complete answer to the problem for the irreducible groups.


title: Equiangular line systems and switching classes containing regular graphs

abstract:
  We develop the theory of equiangular lines in Euclidean spaces. Our focus is
on the question of when a Seidel matrix having precisely three distinct
eigenvalues has a regular graph in its switching class. We make some progress
towards an answer to this question by finding some necessary conditions and
some sufficient conditions. Furthermore, we show that the cardinality of an
equiangular line system in $18$ dimensional Euclidean space is at most $60$.


title:
Mixed and componentwise condition numbers for a linear function of the
  solution of the linear least squares problem with equality constrains

abstract:
  In this paper, we consider the mixed and componentwise condition numbers for
a linear function of the solution to the linear least squares problem with
equality constrains (LSE). We derive the explicit expressions of the mixed and
componentwise condition numbers through the dual techniques. The sharp upper
bounds for the derived mixed and componentwise condition numbers are obtained,
which can be estimated efficiently by means of the classical Hager-Higham
algorithm for estimating matrix one-norm during using the generalized QR
factorization method for solving LSE. The numerical examples show that the
derived condition numbers can give sharp perturbation bounds, on the other hand
normwise condition numbers can severely overestimate the relative errors
because normwise condition numbers ignore the data sparsity and scaling.


title: Breakdown of the Nagaoka phase at finite doping

abstract:
  The Nagaoka ($U=\infty$) limit of the Hubbard model on a square lattice is
mapped onto the itinerant-localized Kondo model at infinitely strong coupling.
Such a model is well suited to perform quantum Monte Carlo (QMC) simulations to
compute spin correlation functions. This model is shown to exhibit no
short-range ferromagnetic (FM) spin correlations at any doping $\delta\ge 0.01$
and finite temperature, $T=0.1t$. Our simulations give no indication that there
is a tendency towards ferromagnetic ordering in the ground state.


title: Observations of the $\gamma$-ray pulsar J1932+1916 in X-rays

abstract:
  We present the analysis of the archival Suzaku and Swift X-ray observations
of the young $\gamma$-ray pulsar J1932+1916 field. The data revealed a
point-like object at the $\gamma$-ray position of the pulsar and diffuse X-ray
emission around it. Spectra of the point-like source and diffuse emission are
well-described by absorbed power-law models with spectral parameters typical
for pulsar plus pulsar wind nebula systems. Therefore we suggest that Suzaku
and Swift detected the X-ray counterpart of PSR J1932+1916. Assuming this
interpretation, we constrain the distance to the pulsar in the range of 2-6
kpc. We also suggest possible association of the pulsar with the nearby
supernova remnant G54.4-0.3 and discuss its implications for the pulsar proper
motion, age and distance.


title:
Statistically convex-cocompact actions of groups with contracting
  elements

abstract:
  This paper presents a study of the asymptotic geometry of groups with
contracting elements, with emphasis on a subclass of statistically
convex-cocompact (SCC) actions. The class of SCC actions includes relatively
hyperbolic groups, CAT(0) groups with rank-1 elements and mapping class groups,
among others. We exploit an extension lemma to prove that a group with SCC
actions contains large free sub-semigroups, has purely exponential growth and
contains a class of barrier-free sets with a growth-tight property. Our study
produces new results and recovers existing ones for many interesting groups
through a unified and elementary approach.


title: Hierarchical searching in episodic memory

abstract:
  An analysis of free-recall datasets from two independent experiments allows
to identify two anomalous instances of non-monotonicity in free recall: a
maximum in the dependence of the inter-response intervals on the
serial-position lags, and a minimum in the rate of contiguous recall near the
beginning of the recall process. Both effects, it is argued, may stem from a
hierarchical search protocol in the space of memories. An elementary
random-walk model on binary strings is used to test this hypothesis.


title:
Time Inconsistent Stochastic Control in Continuous Time: Theory and
  Examples

abstract:
  In this paper, which is a continuation of the previously published discrete
time paper we develop a theory for continuous time stochastic control problems
which, in various ways, are time inconsistent in the sense that they do not
admit a Bellman optimality principle. We study these problems within a game
theoretic framework, and we look for Nash subgame perfect equilibrium points.
For a general controlled continuous time Markov process and a fairly general
objective functional we derive an extension of the standard
Hamilton-Jacobi-Bellman equation, in the form of a system of non-linear
equations, for the determination for the equilibrium strategy as well as the
equilibrium value function. As applications of the general theory we study non
exponential discounting, various types of mean variance problems, a point
process example, as well as a time inconsistent linear quadratic regulator. We
also present a study of time inconsistency within the framework of a general
equilibrium production economy of Cox-Ingersoll-Ross type.


title: FastText.zip: Compressing text classification models

abstract:
  We consider the problem of producing compact architectures for text
classification, such that the full model fits in a limited amount of memory.
After considering different solutions inspired by the hashing literature, we
propose a method built upon product quantization to store word embeddings.
While the original technique leads to a loss in accuracy, we adapt this method
to circumvent quantization artefacts. Our experiments carried out on several
benchmarks show that our approach typically requires two orders of magnitude
less memory than fastText while being only slightly inferior with respect to
accuracy. As a result, it outperforms the state of the art by a good margin in
terms of the compromise between memory usage and accuracy.


title:
On the integrability of a discrete analogue of the Kaup-Kupershmidt
  equation

abstract:
  We study a new example of equation obtained as a result of a recent
generalized symmetry classification of differential-difference equations
defined on five points of one-dimensional lattice. We have established that in
the continuous limit this new equation goes into the well-known
Kaup-Kupershmidt equation. We have also proved its integrability by
constructing an $L-A$ pair and conservation laws. Moreover, we present a
possibly new scheme for deriving conservation laws from $L-A$ pairs.


title:
Learning to Drive using Inverse Reinforcement Learning and Deep
  Q-Networks

abstract:
  We propose an inverse reinforcement learning (IRL) approach using Deep
Q-Networks to extract the rewards in problems with large state spaces. We
evaluate the performance of this approach in a simulation-based autonomous
driving scenario. Our results resemble the intuitive relation between the
reward function and readings of distance sensors mounted at different poses on
the car. We also show that, after a few learning rounds, our simulated agent
generates collision-free motions and performs human-like lane change behaviour.


title:
Deciphering the imprint of topology on nonlinear dynamical network
  stability

abstract:
  Coupled oscillator networks show a complex interrelations between topological
characteristics of the network and the nonlinear stability of single nodes with
respect to large but realistic perturbations. We extend previous results on
these relations by incorporating sampling-based measures of the transient
behaviour of the system, its survivability, as well as its asymptotic
behaviour, its basin stability. By combining basin stability and survivability
we uncover novel, previously unknown asymptotic states with solitary,
desynchronized oscillators which are rotating with a frequency different from
their natural one. They occur almost exclusively after perturbations at nodes
with specific topological properties.
  More generally we confirm and significantly refine the results on the
distinguished role tree-shaped appendices play for nonlinear stability. We find
a topological classification scheme for nodes located in such appendices, that
exactly separates them according to their stability properties, thus
establishing a strong link between topology and dynamics. Hence, the results
can be used for the identification of vulnerable nodes in power grids or other
coupled oscillator networks. From this classification we can derive general
design principles for resilient power grids. We find that striving for
homogeneous network topologies facilitates a better performance in terms of
nonlinear dynamical network stability. While the employed second-order
Kuramoto-like model is parametrized to be representative for power grids, we
expect these insights to transfer to other critical infrastructure systems or
complex network dynamics appearing in various other fields.


title:
Radiative corrections to Higgs masses for the MSSM Higgs potential with
  the dimension-six operators

abstract:
  In the framework of the effective field theory approach to heavy
supersymmetry radiative corrections in the Higgs sector of the Minimal
Supersymmetric Standard Model (MSSM) for the effective potential decomposition
up to the dimension-six operators are calculated. Symbolic expressions for the
threshold corrections induced by $F$- and $D$- soft supersymmetry breaking
terms are derived and the Higgs boson mass spectrum respecting the condition
$m_h=$125 GeV for the lightest $CP$-even scalar is evaluated.


title: Metal pad roll instability in liquid metal batteries

abstract:
  The increasing deployment of renewable energies requires three fundamental
changes to the electric grid: more transmission lines, a flexibilisation of the
demand and grid scale energy storage. Liquid metal batteries (LMBs) are
considered these days as a promising means of stationary energy storage. Built
as a stable density stratification of two liquid metals separated by a liquid
salt, LMBs have three main advantages: a low price, a long life-time and
extremely high current densities. In order to be cheap, LMBs have to be built
large. However, battery currents in the order of kilo-amperes may lead to
magnetohydrodynamic (MHD) instabilities, which - in the worst case - may
short-circuit the thin electrolyte layer. The metal pad roll instability, as
known from aluminium reduction cells, is considered as one of the most
dangerous phenomena for LMBs. We develop a numerical model, combining fluid-
and electrodynamics with the volume-of-fluid method, to simulate this
instability in cylindrical LMBs. We explain the instability mechanism similar
to that in aluminium reduction cells and give some first results, including
growth rates and oscillation periods of the instability.


title: Prescribed Gauss curvature problem on singular surfaces

abstract:
  We study the existence of at least one conformal metric of prescribed
Gaussian curvature on a closed surface $\Sigma$ admitting conical singularities
of orders $\alpha_i$'s at points $p_i$'s. In particular, we are concerned with
the case where the prescribed Gaussian curvature is sign-changing. Such a
geometrical problem reduces to solving a singular Liouville equation. By
employing a min-max scheme jointly with a finite dimensional reduction method,
we deduce new perturbative results providing existence when the quantity
$\chi(\Sigma)+\sum_i \alpha_i$ approaches a positive even integer, where
$\chi(\Sigma)$ is the Euler characteristic of the surface $\Sigma$.


title: Statistical characterization of the standard map

abstract:
  The standard map, paradigmatic conservative system in the $(x,p)$ phase
space, has been recently shown to exhibit interesting statistical behaviors
directly related to the value of the standard map parameter $K$. A detailed
numerical description is achieved in the present paper. More precisely, for
large values of $K$, the Lyapunov exponents are neatly positive over virtually
the entire phase space, and, consistently with Boltzmann-Gibbs (BG) statistics,
we verify $q_{\text{ent}}=q_{\text{sen}}=q_{\text{stat}}=q_{\text{rel}}=1$,
where $q_{\text{ent}}$ is the $q$-index for which the nonadditive entropy $S_q
\equiv k \frac{1-\sum_{i=1}^W p_i^q}{q-1}$ (with $S_1=S_{BG} \equiv
-k\sum_{i=1}^W p_i \ln p_i$) grows linearly with time before achieving its
$W$-dependent saturation value; $q_{\text{sen}}$ characterizes the time
increase of the sensitivity $\xi$ to the initial conditions, i.e., $\xi \sim
e_{q_{\text{sen}}}^{\lambda_{q_{\text{sen}}}
\,t}\;(\lambda_{q_{\text{sen}}}>0)$, where $e_q^z \equiv[1+(1-q)z]^{1/(1-q)}$;
$q_{\text{stat}}$ is the index associated with the $q_{\text{stat}}$-Gaussian
distribution of the time average of successive iterations of the
$x$-coordinate; finally, $q_{\text{rel}}$ characterizes the
$q_{\text{rel}}$-exponential relaxation with time of the entropy
$S_{q_{\text{ent}}}$ towards its saturation value. In remarkable contrast, for
small values of $K$, the Lyapunov exponents are virtually zero over the entire
phase space, and, consistently with $q$-statistics, we verify
$q_{\text{ent}}=q_{\text{sen}}=0$, $q_{\text{stat}} \simeq 1.935$, and
$q_{\text{rel}} \simeq1.4$. The situation corresponding to intermediate values
of $K$, where both stable orbits and a chaotic sea are present, is discussed as
well. The present results transparently illustrate when BG or $q$-statistical
behavior are observed.


title: Unraveling reported dreams with text analytics

abstract:
  We investigate what distinguishes reported dreams from other personal
narratives. The continuity hypothesis, stemming from psychological dream
analysis work, states that most dreams refer to a person's daily life and
personal concerns, similar to other personal narratives such as diary entries.
Differences between the two texts may reveal the linguistic markers of dream
text, which could be the basis for new dream analysis work and for the
automatic detection of dream descriptions. We used three text analytics
methods: text classification, topic modeling, and text coherence analysis, and
applied these methods to a balanced set of texts representing dreams, diary
entries, and other personal stories. We observed that dream texts could be
distinguished from other personal narratives nearly perfectly, mostly based on
the presence of uncertainty markers and descriptions of scenes. Important
markers for non-dream narratives are specific time expressions and
conversational expressions. Dream texts also exhibit a lower discourse
coherence than other personal narratives.


title:
A necessary condition for certain functions to preserve positive
  semi-definiteness on partitioned matrices

abstract:
  If $f$ is a symmetric complex-valued function on the $m$-fold Cartesian
product of the set of non-negative reals and $A$ is a positive semi-definite
$m\times m$ matrix with eigenvalues $\lambda_j$, we set
$f(A):=f(\lambda_1,\dotsc,\lambda_m)$. It is shown that if
$[f(A_{\alpha\beta})]$ is positive semi-definite whenever $[A_{\alpha\beta}]$
is a positive semi-definite matrix with positive semi-definite entries
$A_{\alpha\beta}$, then $f$ has a power series expansion with positive
coefficients.


title: Radial Excitations of the Decuplet Baryons

abstract:
  The ground and first excited states of the decuplet baryons are studied using
the two-point QCD sum rule approach. The mass and residue of these states are
computed and compared with the existing experimental data and other theoretical
predictions. The results for the masses of the ground state particles as well
as the excited $ \Delta $ and $ \Sigma^{*} $ states are in good consistency
with experimental data. Our results on the excited $ \Xi^{*} $ and $ \Omega^{-}
$ states reveal that the experimentally poorly known $ \Xi(1950) $ and $
\Omega^{-}(2250) $ can be assigned as the first excited states in $ \Xi^{*} $
and $ \Omega^{-} $ channels, respectively.


title:
On the rate of merging of vorticity level sets for the 2D Euler
  equations

abstract:
  We show that two distinct level sets of the vorticity of a solution to the 2D
Euler equations on a disc can approach each other along a curve at an
arbitrarily large exponential rate.


title:
Analysis and Optimization of Loss Functions for Multiclass, Top-k, and
  Multilabel Classification

abstract:
  Top-k error is currently a popular performance measure on large scale image
classification benchmarks such as ImageNet and Places. Despite its wide
acceptance, our understanding of this metric is limited as most of the previous
research is focused on its special case, the top-1 error. In this work, we
explore two directions that shed more light on the top-k error. First, we
provide an in-depth analysis of established and recently proposed single-label
multiclass methods along with a detailed account of efficient optimization
algorithms for them. Our results indicate that the softmax loss and the smooth
multiclass SVM are surprisingly competitive in top-k error uniformly across all
k, which can be explained by our analysis of multiclass top-k calibration.
Further improvements for a specific k are possible with a number of proposed
top-k loss functions. Second, we use the top-k methods to explore the
transition from multiclass to multilabel learning. In particular, we find that
it is possible to obtain effective multilabel classifiers on Pascal VOC using a
single label per image for training, while the gap between multiclass and
multilabel methods on MS COCO is more significant. Finally, our contribution of
efficient algorithms for training with the considered top-k and multilabel loss
functions is of independent interest.


title:
Frequency-dependent tidal dissipation in a viscoelastic Saturnian core
  and expansion of Mimas' semi-major axis

abstract:
  Regarding tidal dissipation in Saturn, usually parameterized by Saturn's
quality factor Q, there remains a discrepancy between conventional estimates
and the latest determination that has been derived from astrometric
observations of Saturn's inner satellites. If dissipation in Saturn is as large
as the astrometric observations suggest, conventional models predict that
Mimas' initial orbit should be located inside Saturn's synchronous orbit or
even inside its Roche limit. Using simple structure models and assuming
Saturn's core to be viscoelastic, we look for dissipation models which are
consistent with both the latest astrometric observations and with Mimas'
orbital migration. Firstly, using a two-layer model of Saturn's interior
structure, we constrain the ranges of rigidity and viscosity of Saturn's core
which are consistent with Saturn's dissipation derived from astrometric
observations at the tidal frequencies of Enceladus, Tethys, and Dione. Next,
within the constrained viscosity and rigidity ranges, we calculate Mimas'
semi-major axis considering the frequency dependence of viscoelastic
dissipation in Saturn's core. By the two calculations, we evaluate (1)
Saturnian models which can explain the astrometrically determined Saturnian
dissipation, and (2) whether Mimas' initial semi-major axis is larger than the
synchronous orbit. We show that if the core is assumed to be solid with a
viscosity of 10^{13}-10^{14} Pa s, the lower boundary of the observed Saturnian
dissipation at tidal frequencies of Enceladus, Tethys, and Dione can be
explained by our model. In this viscosity range, Mimas can stay outside the
synchronous orbit and the Roche limit for 4.5 billion years of evolution. In
the case of a frequency dependent viscoelastic dissipative core, the lower
boundary of the observed Saturnian dissipation can be consistent with the
orbital expansion of Mimas.


title:
Modeling dynamical ejecta from binary neutron star mergers and
  implications for electromagnetic counterparts

abstract:
  In addition to the emission of gravitational waves (GWs) the coalescence and
merger of two neutron stars will produce a variety of electromagnetic (EM)
signals. In this work we combine a large set of numerical relativity
simulations performed by different groups and we present fits for the mass,
kinetic energy, and the velocities of the dynamical ejected material.
Additionally, we comment on the geometry and composition of the ejecta and
discuss the influence of the stars' individual rotation.
  The derived fits can be used to approximate the luminosity and lightcurve of
the kilonovae (macronovae) and to estimate the main properties of the radio
flares. This correlation between the binary parameters and the EM signals
allows in case of a GW detection to approximate possible EM counterparts when
first estimates of the masses are available. After a possible kilonovae
observation our results could also be used to restrict the region of the
parameter space which has to be covered by numerical relativity simulations.


title:
Conserved Currents in the Six-Vertex and Trigonometric Solid-On-Solid
  Models

abstract:
  We construct quasi-local conserved currents in the six-vertex model with
anisotropy parameter $\eta$ by making use of the quantum-group approach of
Bernard and Felder. From these currents, we construct parafermionic operators
with spin $1+i\eta/\pi$ that obey a discrete-integral condition around lattice
plaquettes embedded into the complex plane. These operators are identified with
primary fields in a $c=1$ compactified free Boson conformal field theory. We
then consider a vertex-face correspondence that takes the six-vertex model to a
trigonometric SOS model, and construct SOS operators that are the image of the
six-vertex currents under this correspondence. We define corresponding SOS
parafermionic operators with spins $s=1$ and $s=1+2i\eta/\pi$ that obey
discrete integral conditions around SOS plaquettes embedded into the complex
plane. We consider in detail the cyclic-SOS case corresponding to the choice
$\eta=i\pi (p-p')/p$, with $p'<p$ coprime. We identify our SOS parafermionic
operators in terms of the screening operators and primary fields of the
associated $c=1-6(p-p')^2/pp'$ conformal field theory.

categories: math-ph cond-mat.stat-mech hep-th math.MP