title:
Graphical Modeling for Multivariate Hawkes Processes with Nonparametric
  Link Functions

abstract:
  Hawkes (1971) introduced a powerful multivariate point process model of
mutually exciting processes to explain causal structure in data. In this paper
it is shown that the Granger causality structure of such processes is fully
encoded in the corresponding link functions of the model. A new nonparametric
estimator of the link functions based on a time-discretized version of the
point process is introduced by using an infinite order autoregression.
Consistency of the new estimator is derived. The estimator is applied to
simulated data and to neural spike train data from the spinal dorsal horn of a
rat.


title: Space-Efficient Karatsuba Multiplication for Multi-Precision Integers

abstract:
  The traditional Karatsuba algorithm for the multiplication of polynomials and
multi-precision integers has a time complexity of $O(n^{1.59})$ and a space
complexity of $O(n)$. Roche proposed an improved algorithm with the same
$O(n^{1.59})$ time complexity but with a much reduced $O(\log n)$ space
complexity. In Roche's paper details were provided for multiplication of
polynomials, but not for multi-precision integers. Multi-precision integers
differ from polynomials by the presence of carries, which poses difficulties in
implementing Roche's scheme in multi-precision integers. This paper provides a
detailed solution to these difficulties. Finally, numerical comparisons between
the schoolbook, traditional Karatsuba, and space-efficient Karatsuba algorithms
are provided.


title: Charged scalar waves from the RN/CFT correspondence

abstract:
  We examine new tests for (non-)extremal Reissner-Nordstr\"om/Conformal field
theory correspondences (RN/CFT) in this paper. The decay rate of the charged
scalar wave sourced by an orbiting star around the black hole is computed and
is compared with the decay rate computed in the corresponding CFT. We find that
precise matches are achieved.


title:
Exceptionally strong correlation-driven charge migration and attosecond
  transient absorption spectroscopy

abstract:
  We investigate theoretically charge migration following prompt double
ionization of a polyatomic molecule (C$_2$H$_4$BrI) and find that for double
ionization, correlation-driven charge migration appears to be particularly
prominent, i.e., we observe exceptionally rich dynamics solely driven by the
electron-electron interaction even in the situation when the electrons are
emitted from outer-valence orbitals. These strongly correlated electron
dynamics are witnessed in the theoretically determined time-resolved transient
absorption cross section. Strikingly, features in the cross section can be
traced back to electron hole populations and time-dependent partial charges and
hence, can be interpreted with surprising ease. Remarkably, by taking advantage
of element specific core-to-valence transitions, the hole population dynamics
can be followed both in time and space. With this, not only do we report the
high relevance of correlation-driven charge migration following double
ionization but our findings also highlight the outstanding role of attosecond
transient absorption spectroscopy (ATAS) as one of the most promising
techniques for monitoring ultrafast electron dynamics in complex molecular
systems.


title: Radii of starlikeness and convexity of regular Coulomb wave functions

abstract:
  In this paper our aim is to determine the radii of univalence, starlikeness
and convexity of the normalized regular Coulomb wave functions for two
different kinds of normalization. The key tools in the proof of our main
results are the Mittag-Leffler expansion for regular Coulomb wave functions,
and properties of zeros of the regular Coulomb wave functions and their
derivatives. Moreover, by using the technique of differential subordinations we
present some conditions on the parameters of the regular Coulomb wave function
in order to have a starlike normalized form. In addition, by using the
Euler-Rayleigh inequalities we obtain some tight bounds for the radii of
starlikeness of the normalized regular Coulomb wave functions. Some open
problems for the zeros of the regular Coulomb wave functions are also stated
which may be of interest for further research.


title: 3D Face Tracking and Texture Fusion in the Wild

abstract:
  We present a fully automatic approach to real-time 3D face reconstruction
from monocular in-the-wild videos. With the use of a cascaded-regressor based
face tracking and a 3D Morphable Face Model shape fitting, we obtain a
semi-dense 3D face shape. We further use the texture information from multiple
frames to build a holistic 3D face representation from the video frames. Our
system is able to capture facial expressions and does not require any
person-specific training. We demonstrate the robustness of our approach on the
challenging 300 Videos in the Wild (300-VW) dataset. Our real-time fitting
framework is available as an open source library at http://4dface.org.


title:
Probing Multi-Strange Dibaryon with Proton-Omega Correlation in
  High-energy Heavy Ion Collisions

abstract:
  Two-particle intensity correlation between the proton ($p$) and the
Omega-baryon ($\Omega$) in high-energy heavy ion collisions is studied to
unravel the possible spin-2 $p\Omega$ dibaryon recently suggested by lattice
QCD simulations. The ratio of correlation functions between small and large
collision systems, $C_{\rm SL}(Q)$, is proposed to be a new measure to extract
the strong $p\Omega$ interaction without much contamination from the Coulomb
attraction. Relevance of this quantity to the experimental observables in
heavy-ion collisions is also discussed.


title:
Quasi-particle bases of principal subspaces of the affine Lie algebra of
  type $G_2^{(1)}$

abstract:
  The aim of this work is to construct the quasi-particle basis of principal
subspace of standard module of highest weight $k\Lambda_0$ of level $k\geq 1$
of affine Lie algebra of type $G_2^{(1)}$ by means of which we obtain the basis
of principal subspace of generalized Verma module.


title: Hochschild Cohomology of Reduced Incidence Algebras

abstract:
  We compute the Hochschild cohomology of the reduced incidence algebras such
as the algebra of formal power series, the algebra of exponential power series,
the algebra of Eulerian power series, and the algebra of formal Dirichlet
series. We achieve the result by carrying out the computation on the coalgebra
${\rm Cotor}$-groups of their pre-dual coalgebras. Using the same coalgebraic
machinery, we further identify the Hochschild cohomology groups of an incidence
algebra associated to a quiver with the ${\rm Ext}$-groups of the incidence
algebra associated to a suspension of the quiver.


title: A generalization of Kantorovich operators for convex compact subsets

abstract:
  In this paper we introduce and study a new sequence of positive linear
operators acting on function spaces defined on a convex compact subset. Their
construction depends on a given Markov operator, a positive real number and a
sequence of probability Borel measures. By considering special cases of these
parameters for particular convex compact subsets we obtain the classical
Kantorovich operators defined in the one-dimensional and multidimensional
setting together with several of their wide-ranging generalizations scattered
in the literature. We investigate the approximation properties of these
operators by also providing several estimates of the rate of convergence.
Finally, the preservation of Lipschitz-continuity as well as of convexity are
discussed


title:
Dynamics and habitability in circumstellar planetary systems of known
  binary stars

abstract:
  We present a survey on exoplanetary systems of binary stars with stellar
separations less than 100 au. For a sample of 11 binaries that harbour detected
circumstellar giant planets we investigate the frequency of systems with
secular resonances (SR) affecting the habitable zone (HZ). Secular resonances
are connected to dynamically unstable or chaotic regions by enforcing highly
eccentric motion. We apply a semi-analytical method to determine the locations
of linear SR, which is based on finding the apsidal precession frequencies of
the massive bodies. For configurations where the giant planet is located
exterior to the HZ we find that there is always a SR interior to its orbit, the
exact location of the SR strongly depends on the system's architecture. In
systems with the giant planet interior to the HZ no SR can occur in the
Newtonian framework. Taking into account the general relativistic precession of
the perihelion, which increases the precession frequencies, planets with $a <
0.1$ au can cause SR in the HZ. We find two cases where the SR is located
inside the HZ, and some more where it is close to the HZ. Generally, giant
planets interior to the HZ are more favourable than exterior planets to avoid
SR in the HZ. Around the location of the SR weaker mean-motion resonances are
excited, and resonance overlap is possible. Existing analytical models are not
as accurate as the semi-analytical method in locating the SR and deviate by
$\sim 0.1$ au or more.


title: Automatic Construction of Discourse Corpora for Dialogue Translation

abstract:
  In this paper, a novel approach is proposed to automatically construct
parallel discourse corpus for dialogue machine translation. Firstly, the
parallel subtitle data and its corresponding monolingual movie script data are
crawled and collected from Internet. Then tags such as speaker and discourse
boundary from the script data are projected to its subtitle data via an
information retrieval approach in order to map monolingual discourse to
bilingual texts. We not only evaluate the mapping results, but also integrate
speaker information into the translation. Experiments show our proposed method
can achieve 81.79% and 98.64% accuracy on speaker and dialogue boundary
annotation, and speaker-based language model adaptation can obtain around 0.5
BLEU points improvement in translation qualities. Finally, we publicly release
around 100K parallel discourse data with manual speaker and dialogue boundary
annotation.


title: Simple source for large linear cluster photonic states

abstract:
  The experimental realization of many-body entangled states is one of the main
goals of quantum technology as these states are a key resource for quantum
computation and quantum sensing. However, increasing the number of photons in
an entangled state has been proved to be a painstakingly hard task. This is a
result of the non-deterministic emission of current photon sources and the
distinguishability between photons from different sources. Moreover, the
generation rate and the complexity of the optical setups hinder scalability.
Here we present a new scheme that is compact, requires a very modest amount of
components, and avoids the distinguishability issues by using only one
single-photon source. States of any number of photons are generated with the
same configuration, with no need for increasing the optical setup. The basic
operation of this scheme is experimentally demonstrated and its sensitivity to
imperfections is considered.


title: Model Building with Non-Compact Cosets

abstract:
  We explore Goldstone boson potentials in non-compact cosets of the form
SO(n,1)/SO(n). We employ a geometric approach to find the scalar potential, and
focus on the conditions under which it is compact in the large field limit. We
show that such a potential is found for a specific misalignment of the vacuum.
This result has applications in different contexts, such as in Composite Higgs
scenarios and theories for the Early Universe. We work out an example of
inflation based on a non-compact coset which makes predictions which are
consistent with the current observational data.


title: Tensor Network States with Three-Site Correlators

abstract:
  We present a detailed analysis of various tensor network parameterizations
within the Complete Graph Tensor Network States (CGTNS) approach. We extend our
2-site CGTNS scheme by introducing 3-site correlators. For this we devise three
different strategies. The first relies solely on 3-site correlators and the
second on 3-site correlators added on top of the 2-site correlator ansatz. To
avoid an inflation of the variational space introduced by higher-order
correlators, we limit the number of higher-order correlators to the most
significant ones in the third strategy. Approaches for the selection of these
most significant correlators are discussed. The sextet and doublet spin states
of the spin-crossover complex manganocene serve as a numerical test case. In
general, the CGTNS scheme achieves a remarkable accuracy for a significantly
reduced size of the variational space. The advantages, drawbacks, and
limitations of all CGTNS parameterizations investigated are rigorously
discussed.

categories: quant-ph cond-mat.str-el physics.chem-ph physics.comp-ph


title: Congruent numbers on the right trapezoid

abstract:
  We introduce and study a new kind of congruent number problem on the right
trapezoid.


title:
Weak solutions of fractional differential equations in non cylindrical
  domain

abstract:
  We study a time fractional heat equation in a noncylindrical domain. The
problem is one-dimensional. We prove existence of properly defined weak
solutions by means of the Galerkin approximation.


title:
Sparse Signal Reconstruction with Multiple Side Information using
  Adaptive Weights for Multiview Sources

abstract:
  This work considers reconstructing a target signal in a context of
distributed sparse sources. We propose an efficient reconstruction algorithm
with the aid of other given sources as multiple side information (SI). The
proposed algorithm takes advantage of compressive sensing (CS) with SI and
adaptive weights by solving a proposed weighted $n$-$\ell_{1}$ minimization.
The proposed algorithm computes the adaptive weights in two levels, first each
individual intra-SI and then inter-SI weights are iteratively updated at every
reconstructed iteration. This two-level optimization leads the proposed
reconstruction algorithm with multiple SI using adaptive weights (RAMSIA) to
robustly exploit the multiple SIs with different qualities. We experimentally
perform our algorithm on generated sparse signals and also correlated feature
histograms as multiview sparse sources from a multiview image database. The
results show that RAMSIA significantly outperforms both classical CS and CS
with single SI, and RAMSIA with higher number of SIs gained more than the one
with smaller number of SIs.


title: Constraints on the presence of SiO gas in the debris disk of HD 172555

abstract:
  We have carried out two sets of observations to quantify the properties of
SiO gas in the unusual HD 172555 debris disk: (1) a search for the J=8-7
rotational transition from the vibrational ground state, carried out with the
APEX sub-millimeter telescope and heterodyne receiver at 863 microns, and (2) a
search at 8.3 microns for the P(17) ro-vibrational transition of gas phase SiO,
carried out with VLT/VISIR with a resolution, $\lambda/\Delta\lambda$, of
30000. The APEX measurement resulted in a 3 $\sigma$ non-detection of an
interstellar feature, but only an upper limit to emission at the radial
velocity and linewidth expected from HD 172555. The VLT/VISIR result was also
an upper limit. These were used to provide limits for the abundance of gas
phase SiO, for a range of temperatures. The upper limit from our APEX
detection, assuming an 8000 K primary star photospheric excitation, falls more
than an order of magnitude below the self-shielding stability threshold derived
by Johnson et al. (2012). Our results thus favor a solid-state origin for the
8.3 micron feature seen in the Spitzer IRS spectrum of the circumstellar excess
emission, and the production of circumstellar O$^+$ and Si$^+$ by SiO UV
photolysis. The implications of these estimates are explored in the framework
of models of the HD 172555 circumstellar disk.


title:
openXBOW - Introducing the Passau Open-Source Crossmodal Bag-of-Words
  Toolkit

abstract:
  We introduce openXBOW, an open-source toolkit for the generation of
bag-of-words (BoW) representations from multimodal input. In the BoW principle,
word histograms were first used as features in document classification, but the
idea was and can easily be adapted to, e.g., acoustic or visual low-level
descriptors, introducing a prior step of vector quantisation. The openXBOW
toolkit supports arbitrary numeric input features and text input and
concatenates computed subbags to a final bag. It provides a variety of
extensions and options. To our knowledge, openXBOW is the first publicly
available toolkit for the generation of crossmodal bags-of-words. The
capabilities of the tool are exemplified in two sample scenarios:
time-continuous speech-based emotion recognition and sentiment analysis in
tweets where improved results over other feature representation forms were
observed.


title:
Nonlinear Mixed-effects Scalar-on-function Models and Variable Selection
  for Kinematic Upper Limb Movement Data

abstract:
  This paper arises from collaborative research the aim of which was to model
clinical assessments of upper limb function after stroke using 3D kinematic
data. We present a new nonlinear mixed-effects scalar-on-function regression
model with a Gaussian process prior focusing on variable selection from large
number of candidates including both scalar and function variables. A novel
variable selection algorithm has been developed, namely functional least angle
regression (fLARS). As they are essential for this algorithm, we studied the
representation of functional variables with different methods and the
correlation between a scalar and a group of mixed scalar and functional
variables. We also propose two new stopping rules for practical usage.
  This algorithm is able to do variable selection when the number of variables
is larger than the sample size. It is efficient and accurate for both variable
selection and parameter estimation. Our comprehensive simulation study showed
that the method is superior to other existing variable selection methods. When
the algorithm was applied to the analysis of the 3D kinetic movement data the
use of the non linear random-effects model and the function variables
significantly improved the prediction accuracy for the clinical assessment.


title:
Semi-analytic version of shooting method and the bound states in
  non-analytic potential $V(x)= -g^2\exp (-|x|)$

abstract:
  People construct quantum bound states either non-numerically (in not too many
exceptional cases) or, in general, numerically (mainly using majorization or
discretization techniques). We point out that there exists a class of
interactions "in between". Being, in conventional terminology, neither exactly
solvable nor purely numerical. The idea is illustrated by the elementary
exponential-well toy-model potential $V(x)= -g^2\exp (-|x|)$.


title: Spin control of light with hyperbolic metasurfaces

abstract:
  Transverse spin angular momentum is an inherent feature of evanescent waves
which may have applications in nanoscale optomechanics, spintronics, and
quantum information technology due to the robust spin-directional coupling.
Here we analyze a local spin angular momentum density of hybrid surface waves
propagating along anisotropic hyperbolic metasurfaces. We reveal that, in
contrast to bulk plane waves and conventional surface plasmons at isotropic
interfaces, the spin of the hybrid surface waves can be engineered to have an
arbitrary angle with the propagation direction. This property allows to tailor
directivity of surface waves via the magnetic control of the spin projection of
quantum emitters, and it can be useful for optically controlled spin transfer.


title: Entangled light from bimodal optical nanoantennas

abstract:
  We suggest a hybrid plasmonic device consisting of a bimodal metallic
nanoantenna coupled to an incoherently pumped quantum emitter. This hybrid
device emits light into the two modes entangled in the number of photons. The
process is a prime example where losses are turned from a nuisance into
something beneficial, since, even though counterintuitively, the entanglement
is enabled by strong incoherent processes, i.e. dominant scattering and
absorption rates of the nanoantenna. Both, the high emission rate and the
degree of entanglement of the emitted light are insensitive with respect to
imperfections in the nanoantenna geometry, rendering the scheme feasible for an
implementation.


title: A conformally invariant variational problem for time-like curves

abstract:
  We study the conformally invariant variational problem for time-like curves
in the $n$-dimensional Einstein universe defined by the conformal strain
functional. We prove that the stationary curves are trapped into an Einsetin
universe of dimension $2$, $3$ or $4$. We study the linearly-full stationary
curves in a four-dimensional Einstein universe and we show that they can be
integrated by quadratures in terms of elliptic functions, elliptic integrals
and Jacobi's theta functions.


title: Planck scale effect on the thermodynamics of photon gas

abstract:
  A particular framework for quantum gravity is the doubly special relativity
(DSR) formalism that introduces a new observer independent scale (the Planck
scale). We resort to the methods of statistical mechanics in this framework to
determine how the deformed dispersion relation affects the thermodynamics of a
photon gas. The ensuing modifications to the density of states, partition
function, pressure, internal energy, entropy, free energy and specific heat are
calculated. These results are compared with the outcome obtained in the Lorentz
violating model of Camacho and Marcias (Gen. Relativ. Gravit. 39: 1175-1183,
2007). The two types of models predict different results due to different
spacetime structure near the Planck scale. The resulting modifications can be
interpreted as a consequence of the deformed Lorentz symmetry present in the
particular model we have considered. In the low energy limit, our calculation
coincides with usual results of photon thermodynamics in special relativity
(SR) theory, in contrast to the study presented in (Phys. Rev. D81, 085039
(2010)).


title: Fractal snowflake domain diffusion with boundary and interior drifts

abstract:
  We study a parabolic Ventsell problem for a second order differential
operator in divergence form and with interior and boundary drift terms on the
snowflake domain. We prove that under standard conditions a related Cauchy
problem possesses a unique classical solution and explain in which sense it
solves a rigorous formulation of the initial Ventsell problem. As a second
result we prove that functions that are intrinsically Lipschitz on the
snowflake boundary admit Euclidean Lipschitz extensions to the closure of the
entire domain. Our methods combine the fractal membrane analysis, the vector
analysis for local Dirichlet forms and PDE on fractals, coercive closed forms,
and the analysis of Lipschitz functions.


title: Dynamical Quantum Tomography

abstract:
  We consider quantum state tomography with measurement procedures of the
following type: First, we subject the quantum state we aim to identify to a
know time evolution for a desired period of time. Afterwards we perform a
measurement with a fixed measurement set-up. This procedure can then be
repeated for other periods of time, the measurement set-up however remains
unaltered. Given an $n$-dimensional system with suitable unitary dynamics, we
show that any two states can be discriminated by performing a measurement with
a set-up that has $n$ outcomes at $n+1$ points in time. Furthermore, we
consider scenarios where prior information restricts the set of states to a
subset of lower dimensionality. Given an $n$-dimensional system with suitable
unitary dynamics and a semi-algebraic subset $\mathcal{R}$ of its state space,
we show that any two states of the subset can be discriminated by performing a
measurement with a set-up that has $n$ outcomes at $l$ steps of the time
evolution if $(n-1)l\ge 2\dim\mathcal{R}$. In addition, by going beyond unitary
dynamics, we show that one can in fact reduce to a set-up with the minimal
number of two outcomes.


title:
Disentangling surface and bulk transport in topological-insulator
  $p$-$n$ junctions

abstract:
  By combining $n$-type $\mathrm{Bi_2Te_3}$ and $p$-type $\mathrm{Sb_2Te_3}$
topological insulators, vertically stacked $p$-$n$ junctions can be formed,
allowing to position the Fermi level into the bulk band gap and also tune
between $n$- and $p$-type surface carriers. Here we use low-temperature
magnetotransport measurements to probe the surface and bulk transport modes in
a range of vertical $\mathrm{Bi_2Te_3/Sb_2Te_3}$ heterostructures with varying
relative thicknesses of the top and bottom layers. With increasing thickness of
the $\mathrm{Sb_2Te_3}$ layer we observe a change from $n$- to $p$-type
behavior via a specific thickness where the Hall signal is immeasurable.
Assuming that the the bulk and surface states contribute in parallel, we can
calculate and reproduce the dependence of the Hall and longitudinal components
of resistivity on the film thickness. This highlights the role played by the
bulk conduction channels which, importantly, cannot be probed using surface
sensitive spectroscopic techniques. Our calculations are then buttressed by a
semi-classical Boltzmann transport theory which rigorously shows the vanishing
of the Hall signal. Our results provide crucial experimental and theoretical
insights into the relative roles of the surface and bulk in the vertical
topological $p$-$n$ junctions.


title: Ground states for a fractional scalar field problem with critical growth

abstract:
  We prove the existence of a ground state solution for the following
fractional scalar field equation $(-\Delta)^{s} u= g(u)$ in $\mathbb{R}^{N}$
where $s\in (0,1), N> 2s$,$ (-\Delta)^{s}$ is the fractional Laplacian, and
$g\in C^{1, \beta}(\mathbb{R}, \mathbb{R})$ is an odd function satisfying the
critical growth assumption.


title: Maps of Mori dream spaces

abstract:
  Given a map $\phi: X \to Y$ of $\mathbb Q$-factorial Mori dream spaces, one
can ask whether this map is induced by a homogeneous homomorphism $R(Y) \to
R(X)$ of Cox rings. As soon as $Y$ is singular, such a homomorphism needs not
to exist, as pulling back Weil divisors is not well-defined. In this article,
we prove that there is a unique Cox lift $\Phi: \mathcal X \to \mathcal Y$ of
Mori dream stacks coming from a homogeneous homomorphism $R(Y) = R(\mathcal Y)
\to R(\mathcal X)$, where $\mathcal Y$ is a canonical stack to $Y$ and
$\mathcal X$ is obtained from $X$ by root constructions. Moreover, $\phi$ is
induced from $\Phi$ by passing to coarse moduli spaces.


title:
Model distinguishability and inference robustness in mechanisms of
  cholera transmission and loss of immunity

abstract:
  Mathematical models of cholera and waterborne disease vary widely in their
structures, in terms of transmission pathways, loss of immunity, and other
features. These differences may yield different predictions and parameter
estimates from the same data. Given the increasing use of models to inform
public health decision-making, it is important to assess distinguishability
(whether models can be distinguished based on fit to data) and inference
robustness (whether model inferences are robust to realistic variations in
model structure). We examined the effects of uncertainty in model structure in
epidemic cholera, testing a range of models based on known features of cholera
epidemiology. We fit to simulated epidemic and long-term data, as well as data
from the 2006 Angola epidemic. We evaluated model distinguishability based on
data fit, and whether parameter values and forecasts can accurately be inferred
from incidence data. In general, all models were able to successfully fit to
all data sets, even if misspecified. However, in the long-term data, the best
model fits were achieved when the loss of immunity form matched those of the
model that simulated the data. Two transmission and reporting parameters were
accurately estimated across all models, while the remaining showed broad
variation across the different models and data sets. Forecasting efforts were
not successful early, but once the epidemic peak had been achieved, most models
showed similar accuracy. Our results suggest that we are unlikely to be able to
infer mechanistic details from epidemic case data alone, underscoring the need
for broader data collection. Nonetheless, with sufficient data, conclusions
from forecasting and some parameter estimates were robust to variations in the
model structure, and comparative modeling can help determine how variations in
model structure affect conclusions drawn from models and data.


title: On reduced polytopes

abstract:
  A convex body $R$ in $\mathbb R^d$ is called reduced if the minimal width
$\Delta(R')$ of each convex body $R'\subset R$ different from $R$ is strictly
smaller than the minimal width $\Delta(R)$ of $R$. In this article we construct
a reduced polytope in $\mathbb R^3$, i.e. we answer the following question
posed by Lassak: do there exist reduced polytopes in $\mathbb R^d$,
$d\geqslant3$? Also, we prove some properties of reduced polytopes in $\mathbb
R^3$.


title: Active Nearest-Neighbor Learning in Metric Spaces

abstract:
  We propose a pool-based non-parametric active learning algorithm for general
metric spaces, called MArgin Regularized Metric Active Nearest Neighbor
(MARMANN), which outputs a nearest-neighbor classifier. We give prediction
error guarantees that depend on the noisy-margin properties of the input
sample, and are competitive with those obtained by previously proposed passive
learners. We prove that the label complexity of MARMANN is significantly lower
than that of any passive learner with similar error guarantees. MARMANN is
based on a generalized sample compression scheme, and a new label-efficient
active model-selection procedure.


title: Multimetric Supergravities

abstract:
  Making use of integral forms and superfield techniques we propose
supersymmetric extensions of the multimetric gravity Lagrangians in dimensions
one, two, three and four. The supersymmetric interaction potential covariantly
deforms the bosonic one, producing in particular suitable super-symmetric
polynomials generated by the Berezinian. As an additional application of our
formalism we construct supersymmetric multi-Maxwell theories in dimensions
three and four.


title: Model category of diffeological spaces

abstract:
  The existence of a model structure on the category $\mathcal{D}$ of
diffeological spaces is crucial to developing smooth homotopy theory. We
construct a compactly generated model structure on the category $\mathcal{D}$
whose weak equivalences are just smooth maps inducing isomorphisms on smooth
homotopy groups. The essential part of our construction of the model structure
on $\mathcal{D}$ is to introduce diffeologies on the sets $\Delta^{p}$ $(p \geq
0)$ such that $\Delta^{p}$ contains the $k^{th}$ horn $\Lambda^{p}_{k}$ as a
smooth deformation retract.


title: The Main Results of the Borexino Experiment

abstract:
  The main physical results on the registration of solar neutrinos and the
search for rare processes obtained by the Borexino collaboration to date are
presented.


title: Interpretable Distribution Features with Maximum Testing Power

abstract:
  Two semimetrics on probability distributions are proposed, given as the sum
of differences of expectations of analytic functions evaluated at spatial or
frequency locations (i.e, features). The features are chosen so as to maximize
the distinguishability of the distributions, by optimizing a lower bound on
test power for a statistical test using these features. The result is a
parsimonious and interpretable indication of how and where two distributions
differ locally. An empirical estimate of the test power criterion converges
with increasing sample size, ensuring the quality of the returned features. In
real-world benchmarks on high-dimensional text and image data, linear-time
tests using the proposed semimetrics achieve comparable performance to the
state-of-the-art quadratic-time maximum mean discrepancy test, while returning
human-interpretable features that explain the test results.


title: Low Gilbert damping in Co2FeSi and Fe2CoSi films

abstract:
  Thin highly textured Fe$_{\mathrm{1+x}}$Co$_{\mathrm{2-x}}$Si ($0 \leq$ x
$\leq 1$) films were prepared on MgO (001) substrates by magnetron
co-sputtering. The magneto-optic Kerr effect (MOKE) and ferromagnetic resonance
(FMR) measurements were used to investigate the composition dependence of the
magnetization, the magnetic anisotropy, the gyromagnetic ratio and the
relaxation of the films. The effective magnetization for the thin
Fe$_{\mathrm{1+x}}$Co$_{\mathrm{2-x}}$Si films, determined by FMR measurements,
are consistent with the Slater Pauling prediction. Both MOKE and FMR
measurements reveal a pronounced fourfold anisotropy distribution for all
films. In addition we found a strong influence of the stoichiometry on the
anisotropy as the cubic anisotropy strongly increases with increasing Fe
concentration. The gyromagnetic ratio is only weakly dependent on the
composition. We find low Gilbert damping parameters for all films with values
down to $0.0012\pm0.00012$ for Fe$_{1.75}$Co$_{1.25}$Si. The effective damping
parameter for Co$_2$FeSi is found to be $0.0018\pm 0.0004$. We also find a
pronounced anisotropic relaxation, which indicates significant contributions of
two-magnon scattering processes that is strongest along the easy axes of the
films. This makes thin Fe$_{\mathrm{1+x}}$Co$_{\mathrm{2-x}}$Si films ideal
materials for the application in STT-MRAM devices.


title:
Performance of Resistive Plate Chambers installed during the first long
  shutdown of the CMS experiment

abstract:
  The CMS experiment, located at the CERN Large Hadron Collider, has a
redundant muon system composed by three different detector technologies:
Cathode Strip Chambers (in the forward regions), Drift Tubes (in the central
region) and Resistive Plate Chambers (both its central and forward regions).
All three are used for muon reconstruction and triggering. During the first
long shutdown (LS1) of the LHC (2013-2014) the CMS muon system has been
upgraded with 144 newly installed RPCs on the forth forward stations. The new
chambers ensure and enhance the muon trigger efficiency in the high luminosity
conditions of the LHC Run2. The chambers have been successfully installed and
commissioned. The system has been run successfully and experimental data has
been collected and analyzed. The performance results of the newly installed
RPCs will be presented.


title: Textual Paralanguage and its Implications for Marketing Communications

abstract:
  Both face-to-face communication and communication in online environments
convey information beyond the actual verbal message. In a traditional
face-to-face conversation, paralanguage, or the ancillary meaning- and
emotion-laden aspects of speech that are not actual verbal prose, gives
contextual information that allows interactors to more appropriately understand
the message being conveyed. In this paper, we conceptualize textual
paralanguage (TPL), which we define as written manifestations of nonverbal
audible, tactile, and visual elements that supplement or replace written
language and that can be expressed through words, symbols, images, punctuation,
demarcations, or any combination of these elements. We develop a typology of
textual paralanguage using data from Twitter, Facebook, and Instagram. We
present a conceptual framework of antecedents and consequences of brands' use
of textual paralanguage. Implications for theory and practice are discussed.


title: Twisted Blanchfield pairings and symmetric chain complexes

abstract:
  We define the twisted Blanchfield pairing of a symmetric triad of chain
complexes over a group ring Z[G], together with a unitary representation of G
over an Ore domain with involution.
  We prove that the pairing is sesquilinear, and we prove that it is hermitian
and nonsingular under certain extra conditions. A twisted Blanchfield pairing
is then associated to a 3-manifold together with a decomposition of its
boundary into two pieces and a unitary representation of its fundamental group.


title: Keeping Your Distance is Hard

abstract:
  We study the computational complexity of distance games, a class of
combinatorial games played on graphs. A move consists of colouring an
uncoloured vertex subject to it not being at certain distances determined by
two sets, D and S. D is the set of forbidden distances for colouring vertices
in different colors, while S is the set of forbidden distances for the same
colour. The last player to move wins. Well-known examples of distance games are
Node-Kayles, Snort, and Col, whose complexities were shown to be PSPACE-hard.
We show that many more distance games are also PSPACE-hard.


title:
Large influence of capping layers on tunnel magnetoresistance in
  magnetic tunnel junctions

abstract:
  It has been reported in experiments that capping layers which enhance the
perpendicular magnetic anisotropy (PMA) of magnetic tunnel junctions (MTJs)
induce great impact on the tunnel magnetoresistance (TMR). To explore the
essential influence caused by capping layers, we carry out ab initio
calculations on TMR in the X(001)|CoFe(001)|MgO(001)|CoFe(001)|X(001) MTJ,
where X represents the capping layer material which can be tungsten, tantalum
or hafnium. We report TMR in different MTJs and demonstrate that tungsten is an
ideal candidate for a giant TMR ratio. The transmission spectrum in Brillouin
zone is presented. It can be seen that in the parallel condition of MTJ, sharp
transmission peaks appear in the minority-spin channel. This phenomenon is
attributed to the resonant tunnel transmission effect and we explained it by
the layer-resolved density of states (DOS). In order to explore transport
properties in MTJs, the density of scattering states (DOSS) was studied from
the point of band symmetry. It has been found that CoFe|tungsten interface
blocks scattering states transmission in the anti-parallel condition. This work
reports TMR and transport properties in MTJs with different capping layers, and
proves that tungsten is a proper capping layer material, which would benefit
the design and optimization of MTJs.


title: $\chi_{c1}$ and $\chi_{c2}$ production at $e^+e^-$ colliders

abstract:
  Direct, resonant production of the charmonium states $\chi_{c1}$ and
$\chi_{c2}$ in electron-positron annihilation is investigated. Depending on
details of the model, a sizeable variation of the prediction for the production
cross section is anticipated. It is demonstrated that resonant production could
be observed under favorable circumstances.


title: Harmonic almost Hermitian structures

abstract:
  This is a survey of old and new results on the problem when a compatible
almost complex structure on a Riemannian manifold is a harmonic section or a
harmonic map from the manifold into its twistor space. In this context, a
special attention is paid to the Atiyah-Hitchin-Singer and Eells-Salamon almost
complex structures on the twistor space of an oriented Riemannain
four-manifold.


title: Fractional Choquard Equation with Critical Nonlinearities

abstract:
  In this article, we study the Brezis-Nirenberg type problem of nonlinear
Choquard equation involving a fractional Laplacian \[ (-\De)^s u = \left(
\int_{\Om}\frac{|u|^{2^*_{\mu,s}}}{|x-y|^{\mu}}\mathrm{d}y
\right)|u|^{2^*_{\mu,s}-2}u +\la u \; \text{in } \Om,\] where $\Om $ is a
bounded domain in $\mathbb R^n$ with Lipschitz boundary, $\la $ is a real
parameter, $s \in (0,1)$, $n >2s$ and $2^*_{\mu,s}= (2n-\mu)/(n-2s)$ is the
critical exponent in the sense of Hardy-Littlewood-Sobolev inequality. We
obtain some existence, multiplicity, regularity and nonexistence results for
solution of the above equation using variational methods.


title: Some Results and Connections of an Eigendecomposition Problem

abstract:
  We consider the problem of finding nonzero eigenvalues and the corresponding
eigenvectors of a matrix $AA^{\top}$, where $A$ is a special incidence matrix;
This matrix can equivalently be defined based on a match relation between some
sequences. By using a concrete description of the obtained eigenvectors, we
show that these are pairwise orthogonal and satisfy nice properties. The
combinatorial arguments, in the sequel, lead us to obtain formulas for entries
of matrices $W$ and $WA$, where $W$ is the Moore-Penrose pseudo-inverse of $A$.
A special case of this problem has previously found applications in
computational biology. .


title:
Strained band edge characteristics from hybrid density functional theory
  and empirical pseudopotentials: GaAs, GaSb, InAs and InSb

abstract:
  The properties of a semiconductor get drastically modified when the crystal
point group symmetry is broken under an arbitrary strain. We investigate the
family of semiconductors consisting of GaAs, GaSb, InAs and InSb, considering
their electronic band structure and deformation potentials subject to various
strains based on hybrid density functional theory. Guided by these
first-principles results, we develop strain-compliant local pseudopotentials
for use in the empirical pseudopotential method (EPM). We demonstrate that the
newly proposed empirical pseudopotentials perform well close to band edges and
under anisotropic crystal deformations. Using EPM, we explore the heavy
hole-light hole mixing characteristics under different stress directions which
may be useful in manipulating their transport properties and optical selection
rules. The very low 5 Ry cutoff targeted in the generated pseudopotentials
paves the way for large-scale EPM-based electronic structure computations
involving these lattice mismatched constituents.


title:
Unraveling the Formation History of the Black Hole X-ray Binary LMC X-3
  from ZAMS to Present

abstract:
  We have endeavoured to understand the formation and evolution of the black
hole (BH) X-ray binary LMC X-3. We estimate the properties of the system at 4
evolutionary stages: 1) at the Zero Age Main Sequence (ZAMS), 2) just prior to
the supernova (SN) explosion of the primary, 3) just after the SN, and 4) at
the moment of RLO onset.We use a hybrid approach, combining detailed stellar
structure and binary evolution calculations with approximate population
synthesis models. This allows us to estimate potential natal kicks and the
evolution of the BH spin. In the whole analysis we incorporate as model
constraints the most up-to-date observational information, encompassing the
binary's orbital properties, the companion star mass, effective temperature,
surface gravity and radius, as well as the black hole's mass and spin. We find
that LMC X-3 began as a ZAMS system with the mass of the primary star in the
range $M_{\rm{1,ZAMS}}$ = 22-31 $\rm{M_{\odot}}$ and a secondary star of
$M_{\rm{2,ZAMS}} = 5.0-8.3M_{\odot}$, in a wide ($P_{ZAMS} \gtrsim 2.000\, \rm
days$) and eccentric ($e_{\rm{ZAMS}} \gtrsim 0.23$) orbit. Just prior to the
SN, the primary has a mass of $M_{\mathrm{1,preSN}} = 11.1-18.0\,\rm
M_{\odot}$, with the secondary star largely unaffected. The orbital period
decreases to $0.6-1.7\, \rm days$, and is still eccentric $0 \leq
e_{\rm{preSN}} \leq 0.44$. We find that a symmetric SN explosion with no or
small natal kicks (a few tens of $\rm km\, s^{-1}$) imparted on the BH cannot
be formally excluded, however, large natal kicks in excess of $\gtrsim 120
\,\rm km\, s^{-1}$ increase the estimated formation rate by an order of
magnitude. Following the SN, the system has a BH $M_{\mathrm{BH,postSN}} =
6.4-8.2\,\rm M_{\odot}$ and is put into an eccentric orbit. At the RLO onset
the orbit is circularised and it has an orbital period of $P_{\rm{RLO}} =
0.8-1.4\,\rm days$.


title:
Excitation of vibrational soft modes in disordered systems using active
  oscillation

abstract:
  We propose a new method to characterize the spatial distribution of
particles' vibrations in solids with much lower computational costs compared to
the usual normal mode analysis. We excite the specific vibrational mode in a
two dimensional athermal jammed system by giving a small amplitude of active
oscillation to each particle's size with an identical driving frequency. The
response is then obtained as the real time displacements of the particles. We
show remarkable correlations between the real time displacements and the eigen
vectors obtained from conventional normal mode analysis. More importantly, from
these real time displacements, we can measure the participation ratio and
spatial polarization of particles' vibrations. From these measurements, we find
three distinct frequency regimes which characterize the spatial distribution
and correlation of particles' vibrations in jammed amorphous solids.
Furthermore, we can possibly apply this method to a much larger system to
examine the low frequency behaviour of amorphous solids with a much higher
resolution of the frequency space.


title: On extended graphical calculus for categorified quantum $sl(n)$

abstract:
  We study the properties of the extended graphical calculus for categorified
quantum $sl(n)$. The main results include proofs of Reidemeister 2 and
Reidemeister 3-like moves involving strands corresponding to arbitrary
thicknesses and arbitrary colors -- the results that were anounced in [M.
Stosic: Indecomposable objects and Lusztig's canonical basis, Math. Res. Lett.
22, no. 1 (2015), 245-278].


title: VARTOOLS: A Program for Analyzing Astronomical Time-Series Data

abstract:
  This paper describes the VARTOOLS program, which is an open-source
command-line utility, written in C, for analyzing astronomical time-series
data, especially light curves. The program provides a general-purpose set of
tools for processing light curves including signal identification, filtering,
light curve manipulation, time conversions, and modeling and simulating light
curves. Some of the routines implemented include the Generalized Lomb-Scargle
periodogram, the Box-Least Squares transit search routine, the Analysis of
Variance periodogram, the Discrete Fourier Transform including the CLEAN
algorithm, the Weighted Wavelet Z-Transform, light curve arithmetic, linear and
non-linear optimization of analytic functions including support for Markov
Chain Monte Carlo analyses with non-trivial covariances, characterizing and/or
simulating time-correlated noise, and the TFA and SYSREM filtering algorithms,
among others. A mechanism is also provided for incorporating a user's own
compiled processing routines into the program. VARTOOLS is designed especially
for batch processing of light curves, including built-in support for parallel
processing, making it useful for large time-domain surveys such as searches for
transiting planets. Several examples are provided to illustrate the use of the
program.


title: Heralded Control of Mechanical motion by Single Spins

abstract:
  We propose a method to achieve high degree control of nanomechanical
oscillators by coupling their mechanical motion to single spins. By
manipulating the spin alone and measuring its quantum state heralds the cooling
or squeezing of the oscillator even for weak spin-oscillator couplings. We
analytically show that the asymptotic behavior of the oscillator is determined
by a spin-induced thermal filter function whose overlap with the initial
thermal distribution of the oscillator determines its cooling, heating or
squeezing. Counterintuitively, the rate of cooling dependence on the
instantaneous thermal occupancy of the oscillator renders robust cooling or
squeezing even for high initial temperatures and damping rates. We further
estimate how the proposed scheme can be used to control the motion of a thin
diamond cantilever by coupling it to its defect centers at low temperature.


title: Aspects of non-associative structures in physics

abstract:
  We summarize the emergence of non-commutative/non-associative structures in
Dirac's generalization of Maxwell theory, focusing mostly on the magnetic field
analogue of the non-geometric R-flux string model. The cohomological
interpretation of the obstructions to associativity in terms of 3-cocycles and
the use of the star product as alternative to ordinary quantization are also
discussed in this context.


title: Space-Time Tradeoffs for Distributed Verification

abstract:
  Verifying that a network configuration satisfies a given boolean predicate is
a fundamental problem in distributed computing. Many variations of this problem
have been studied, for example, in the context of proof labeling schemes (PLS),
locally checkable proofs (LCP), and non-deterministic local decision (NLD). In
all of these contexts, verification time is assumed to be constant. Korman,
Kutten and Masuzawa [PODC 2011] presented a proof-labeling scheme for MST, with
poly-logarithmic verification time, and logarithmic memory at each vertex.
  In this paper we introduce the notion of a $t$-PLS, which allows the
verification procedure to run for super-constant time. Our work analyzes the
tradeoffs of $t$-PLS between time, label size, message length, and computation
space. We construct a universal $t$-PLS and prove that it uses the same amount
of total communication as a known one-round universal PLS, and $t$ factor
smaller labels. In addition, we provide a general technique to prove lower
bounds for space-time tradeoffs of $t$-PLS. We use this technique to show an
optimal tradeoff for testing that a network is acyclic (cycle free). Our
optimal $t$-PLS for acyclicity uses label size and computation space $O((\log
n)/t)$. We further describe a recursive $O(\log^* n)$ space verifier for
acyclicity which does not assume previous knowledge of the run-time $t$.


title: A non-commutative generalisation of Thurston's gluing equations

abstract:
  In his famous Princeton Notes, Thurston introduced the so-called gluing
equations defining the deformation variety. Later, Kashaev defined a
non-commutative ring from H-triangulations of 3-manifolds and observed that for
trefoil and figure-eight knot complements the abelianization of this ring is
isomorphic to the ring of regular functions on the deformation variety,
\cite{Kashaev-definition_delta_groupoid, def_anneau,
Kashaev-Delta-groupoids_and_ideal_triangulations}. In this paper, we prove that
this is true for any knot complement in a homology sphere. We also analyse some
examples on other manifolds.


title:
The effects of cap layer thickness on the performance of InGaN/GaN MQW
  solar cell

abstract:
  Following letter introduces a theoretical approach to investigate the effect
of two-step GaN barrier layer growth methodology on the performance of
InGaN/GaN MQW solar cell, in which a lower temperature GaN cap layer was grown
on top of each quantum well followed by a higher temperature GaN barrier layer.
Different growth conditions would cause changes in the concentration of trap
level density of states and imperfection sites. The simulation and comparison
of 3 samples each with different cap layer thickness, reveals the fact that
increasing cap layer thickness results in higher quantum efficiency, improved
short circuit density of current and 3.2% increase of the fill factor.


title: Enhanced superconductivity in aluminum-based hyperbolic metamaterials

abstract:
  One of the most important goals of condensed matter physics is materials by
design, i.e. the ability to reliably predict and design materials with a set of
desired properties. A striking example is the deterministic enhancement of the
superconducting properties of materials. Recent experiments have demonstrated
that the metamaterial approach is capable of achieving this goal, such as
tripling the critical temperature Tc in Al-Al2O3 epsilon near zero (ENZ)
core-shell metamaterial superconductors. However, transport properties of such
metamaterials remained much worse compared to conventional superconductors.
Here, we demonstrate that an Al/Al2O3 hyperbolic metamaterial geometry is
capable of a similar Tc enhancement, while having superior transport and
magnetic properties compared to the core-shell metamaterial superconductors.
This result opens up numerous new possibilities for metamaterial enhancement of
Tc in other practically important simple superconductors, such as niobium and
MgB2. It also indicates that the recently discovered hyperbolic properties of
high Tc superconductors may play considerable role in superconductivity
enhancement in cuprates.


title:
Summations associated with Gamma exponentiated exponential Weibull
  distribution

abstract:
  Considering the recently studied Gamma exponentiated exponential Weibull
${\rm GEEW}(\theta)$ probability distribution \cite{PoganySaboor} surprising
infinite summations are obtained for series which building blocks are special
functions like lower and upper incomplete Gamma, Fox--Wright Psi, Meijer $G$ or
Whittaker $W$ functions.


title:
A new approach to the Stein-Tikhomirov method: with applications to the
  second Wiener chaos and Dickman convergence

abstract:
  In this paper, we propose a general means of estimating the rate at which
convergences in law occur. Our approach, which is an extension of the classical
Stein-Tikhomirov method, rests on a new pair of linear operators acting on
characteristic functions. In principle, this method is admissible for any
approximating sequence and any target, although obviously the conjunction of
several favorable factors is necessary in order for the resulting bounds to be
of interest. As we briefly discuss, our approach is particularly promising
whenever some version of Stein's method applies. We apply our approach to two
examples. The first application concerns convergence in law towards targets
$F_\infty$ which belong to the second Wiener chaos (i.e. $F_{\infty}$ is a
linear combination of independent centered chi-squared rvs). We detail an
application to $U$-statistics. The second application concerns convergence
towards targets belonging to the generalized Dickman family of distributions.
We detail an application to a theorem from number theory. In both cases our
method produces bounds of the correct order (up to a logarithmic loss) in terms
of quantities which occur naturally in Stein's method.


title: Automated Resolution Selection for Image Segmentation

abstract:
  It is well-known in image processing that computational cost increases
rapidly with the number and dimensions of the images to be processed. Several
fields, such as medical imaging, routinely use numerous very large images,
which might also be 3D and/or captured at several frequency bands, all adding
to the computational expense. Multiresolution analysis is a method of
increasing the efficiency of the segmentation process. One multiresolution
approach is the coarse-to-fine segmentation strategy, whereby the segmentation
starts at a coarse resolution and is then fine-tuned during subsequent steps.
The starting resolution for segmentation is generally selected arbitrarily with
no clear selection criteria. The research reported in this paper showed that
starting from different resolutions for image segmentation results in different
accuracies and computational times, even for images of the same category
(depicting similar scenes or objects). An automated method for resolution
selection for an input image would thus be beneficial. This paper introduces a
framework for the automated selection of the best resolution for image
segmentation. We propose a measure for defining the best resolution based on
user/system criteria, offering a trade-off between accuracy and computation
time. A learning approach is then introduced for the selection of the
resolution, whereby extracted image features are mapped to the previously
determined best resolution. In the learning process, class (i.e., resolution)
distribution is generally imbalanced, making effective learning from the data
difficult. Experiments conducted with three datasets using two different
segmentation algorithms show that the resolutions selected through learning
enable much faster segmentation than the original ones, while retaining at
least the original accuracy.


title: The Game-Theoretic Formation of Interconnections Between Networks

abstract:
  We introduce a network design game where the objective of the players is to
design the interconnections between the nodes of two different networks $G_1$
and $G_2$ in order to maximize certain local utility functions. In this
setting, each player is associated with a node in $G_1$ and has functional
dependencies on certain nodes in $G_2$. We use a distance-based utility for the
players in which the goal of each player is to purchase a set of edges
(incident to its associated node) such that the sum of the distances between
its associated node and the nodes it depends on in $G_2$ is minimized. We
consider a heterogeneous set of players (i.e., players have their own costs and
benefits for constructing edges). We show that finding a best response of a
player in this game is NP-hard. Despite this, we characterize some properties
of the best response actions which are helpful in determining a Nash
equilibrium for certain instances of this game. In particular, we prove
existence of pure Nash equilibria in this game when $G_2$ contains a star
subgraph, and provide an algorithm that outputs such an equilibrium for any set
of players. Finally, we show that the price of anarchy in this game can be
arbitrarily large.


title:
Epitaxially stabilized iron thin films via effective strain relief from
  steps

abstract:
  We show a new way to stabilize epitaxial structures against transforming bulk
stable phases for Fe thin films on a vicinal Cu(001) surface.
Atomically-resolved observations by scanning tunneling microscopy reveal that
high-density Cu steps serve as strain relievers for keeping
epitaxially-stabilized Fe fcc(001) lattice even at a transient thickness
towards the bulk stable bcc(110) lattice. Spectroscopic measurements further
clarify the intrinsic electronic properties of the fcc Fe thin film in real
space, implying electronic differences between 6 and 7 monolayer thick films
induced by the modification of the lattice constant in the topmost layers.


title: Colossal magnetic phase transition asymmetry in mesoscale FeRh stripes

abstract:
  Coupled order parameters in phase-transition materials can be controlled
using various driving forces such as temperature, magnetic and electric field,
strain, spin-polarized currents and optical pulses. Tuning the material
properties to achieve efficient transitions would enable fast and low-power
electronic devices. Here we show that the first-order metamagnetic phase
transition in FeRh films becomes strongly asymmetric in mesoscale structures.
In patterned FeRh stripes we observed pronounced supercooling and an
avalanche-like abrupt transition from the ferromagnetic to the
antiferromagnetic phase while the reverse transition remains nearly continuous
over a broad temperature range. Although modest asymmetry signatures have been
found in FeRh films, the effect is dramatically enhanced at the mesoscale. The
asymmetry in the transitions is independent of applied magnetic fields and the
activation volume of the antiferromagnetic phase is more than two orders of
magnitude larger than typical magnetic heterogeneities observed in films. The
collective behavior upon cooling results from the role of long-range
ferromagnetic exchange correlations that become important at the mesoscale and
should be a general property of first-order magnetic phase transitions.


title:
Experimental Discovery of the First Nonsymmorphic Topological Insulator
  KHgSb

abstract:
  Topological insulators (TIs) host novel states of quantum matter,
distinguished from trivial insulators by the presence of nontrivial conducting
boundary states connecting the valence and conduction bulk bands. Up to date,
all the TIs discovered experimentally rely on the presence of either time
reversal or symmorphic mirror symmetry to protect massless Dirac-like boundary
states. Very recently, it has been theoretically proposed that several
materials are a new type of TIs protected by nonsymmorphic symmetry, where
glide-mirror can protect novel exotic surface fermions with hourglass-shaped
dispersion. However, an experimental confirmation of such new nonsymmorphic TI
(NSTI) is still missing. Using angle-resolved photoemission spectroscopy, we
reveal that such hourglass topology exists on the (010) surface of crystalline
KHgSb while the (001) surface has no boundary state, which is fully consistent
with first-principles calculations. We thus experimentally demonstrate that
KHgSb is a NSTI hosting hourglass fermions. By expanding the classification of
topological insulators, this discovery opens a new direction in the research of
nonsymmorphic topological properties of materials.


title: Pattern Avoiding Linear Extensions of Rectangular Posets

abstract:
  Inspired by Yakoubov's 2015 investigation of pattern avoiding linear
extensions of the posets called combs, we study pattern avoiding linear
extensions of rectangular posets. These linear extensions are closely related
to standard tableaux. For positive integers $s$ and $t$ we consider two natural
rectangular partial orders on $\{1,2,\ldots,s t\}$, which we call the NE
rectangular order and the EN rectangular order. First we enumerate linear
extensions of both rectangular orders avoiding most sets of patterns of length
three. Then we use both a generating tree and a bijection to show that the
linear extensions of the EN rectangular order which avoid 1243 are counted by
the Fuss-Catalan numbers. Next we use the transfer matrix method to enumerate
linear extensions of the EN rectangular order which avoid 2143. Finally, we
open an investigation of the distribution of the inversion number on pattern
avoiding linear extensions.


title: Determinants of Matrices over Commutative Finite Principal Ideal Rings

abstract:
  In this paper, the determinants of $n\times n$ matrices over commutative
finite chain rings and over commutative finite principal ideal rings are
studied. The number of $n\times n$ matrices over a commutative finite chain
ring ${R}$ of a fixed determinant $a$ is determined for all $a\in {R}$ and
positive integers $n$. Using the fact that every commutative finite principal
ideal ring is a product of commutative finite chain rings, the number of
$n\times n$ matrices of a fixed determinant over a commutative finite principal
ideal ring is shown to be multiplicative, and hence, it can be determined.
These results generalize the case of matrices over the ring of integers modulo
$m$.


title: Complementary Dual Subfield Linear Codes Over Finite Fields

abstract:
  Two families of complementary codes over finite fields $\mathbb{F}_q$ are
studied, where $q=r^2$ is square: i) Hermitian complementary dual linear codes,
and ii) trace Hermitian complementary dual subfield linear codes. Necessary and
sufficient conditions for a linear code (resp., a subfield linear code) to be
Hermitian complementary dual (resp., trace Hermitian complementary dual) are
determined. Constructions of such codes are given together their parameters.
Some illustrative examples are provided as well.


title:
Maps of Mori Dream Spaces in Cox coordinates. Part I: existence of
  descriptions

abstract:
  Any rational map between affine spaces, projective spaces or toric varieties
can be described in terms of their affine, homogeneous, or Cox coordinates. We
show an analogous statement in the setting of Mori Dream Spaces. More precisely
(in the case of regular maps) we show there exists a finite extension of the
Cox ring of the source, such that the regular map lifts to a morphism from the
Cox ring of the target to the finite extension. Moreover the extension only
involves roots of homogeneous elements. Such a description of the map can be
applied in practical computations.


title:
On Hamiltonians with position-dependent mass from Kaluza-Klein
  compactifications

abstract:
  In a recent paper (J.R. Morris, Quant. Stud. Math. Found. 2 (2015) 359), an
inhomogeneous compactification of the extra dimension of a five-dimensional
Kaluza-Klein metric has been shown to generate a position-dependent mass (PDM)
in the corresponding four-dimensional system. As an application of this
dimensional reduction mechanism, a specific static dilatonic scalar field has
been connected with a PDM Lagrangian describing a well-known nonlinear PDM
oscillator. Here we present more instances of this construction that lead to
PDM systems with radial symmetry, and the properties of their corresponding
inhomogeneous extra dimensions are compared with the ones in the nonlinear
oscillator model. Moreover, it is also shown how the compactification
introduced in this type of models can alternatively be interpreted as a novel
mechanism for the dynamical generation of curvature.


title: Determination of the QCD Coupling from ALEPH $\tau$ Decay Data

abstract:
  We present a comprehensive study of the determination of the strong coupling
from $\tau$ decay, using the most recent release of the experimental ALEPH
data. We critically review all theoretical strategies used in previous works
and put forward various novel approaches which allow to study complementary
aspects of the problem. We investigate the advantages and disadvantages of the
different methods, trying to uncover their potential hidden weaknesses and test
the stability of the obtained results under slight variations of the assumed
inputs. We perform several determinations, using different methodologies, and
find a very consistent set of results. All determinations are in excellent
agreement, and allow us to extract a very reliable value for
$\alpha_s(m_\tau^2)$. The main uncertainty originates in the pure perturbative
error from unknown higher orders. Taking into account the systematic
differences between the results obtained with the CIPT and FOPT prescriptions,
we find $\alpha_{s}^{(n_f=3)}(m_\tau^2) = 0.328 \pm 0.013$ which implies
$\alpha_{s}^{(n_f=5)}(M_Z^{2}) = 0.1197\pm 0.0015$.


title: New fermions on the line in topological symmorphic metals

abstract:
  Topological metals and semimetals (TMs) have recently drawn significant
interest. These materials give rise to condensed matter realizations of many
important concepts in high-energy physics, leading to wide-ranging protected
properties in transport and spectroscopic experiments. The most studied TMs,
i.e., Weyl and Dirac semimetals, feature quasiparticles that are direct
analogues of the textbook elementary particles. Moreover, the TMs known so far
can be characterized based on the dimensionality of the band crossing. While
Weyl and Dirac semimetals feature zero-dimensional points, the band crossing of
nodal-line semimetals forms a one-dimensional closed loop. In this paper, we
identify a TM which breaks the above paradigms. Firstly, the TM features
triply-degenerate band crossing in a symmorphic lattice, hence realizing
emergent fermionic quasiparticles not present in quantum field theory.
Secondly, the band crossing is neither 0D nor 1D. Instead, it consists of two
isolated triply-degenerate nodes interconnected by multi-segments of lines with
two-fold degeneracy. We present materials candidates. We further show that
triplydegenerate band crossings in symmorphic crystals give rise to a Landau
level spectrum distinct from the known TMs, suggesting novel magneto-transport
responses. Our results open the door for realizing new topological phenomena
and fermions including transport anomalies and spectroscopic responses in
metallic crystals with nontrivial topology beyond the Weyl/Dirac paradigm.


title:
A total measure of multi-particle quantum correlations in atomic
  Schr\"odinger cat states

abstract:
  We propose a total measure of multi-particle quantum correlation in a system
of N two-level atoms (N qubits). We construct a parameter that encompasses all
possible quantum correlations among N two-level atoms in arbitrary symmetric
pure states and define its numerical value to be the total measure of the net
atom-atom correlations. We use that parameter to quantify the total quantum
correlations in atomic Schr\"{o}dinger cat states, which are generated by the
dispersive interaction in a cavity. We study the variation of the net amount of
quantum correlation as we vary the number of atoms from N=2 to N=100 and obtain
some interesting results. We also study the variation of the net correlation,
for fixed interaction time, as we increase the number of atoms in the excited
state of the initial system, and notice some interesting features. We also
observe the behaviour of the net quantum correlation as we continuously
increase the interaction time, for the general state of N two-level atoms in a
dispersive cavity.


title: The four genus of a link, Levine-Tristram signatures and satellites

abstract:
  We give a new proof that the Levine-Tristram signatures of a link give lower
bounds for the minimal sum of the genera of a collection of oriented, locally
flat, disjointly embedded surfaces that the link can bound in the 4-ball. We
call this minimal sum the 4-genus of the link. We also extend a theorem of
Cochran, Friedl and Teichner to show that the 4-genus of a link does not
increase under infection by a string link, which is a generalised satellite
construction, provided that certain homotopy triviality conditions hold on the
axis curves, and that enough Milnor's invariants of the infection string link
vanish. We construct knots for which the combination of the two results
determines the 4-genus.


title: Dark Matter and Leptogenesis Linked by Classical Scale Invariance

abstract:
  In this work we study a classically scale invariant extension of the Standard
Model that can explain simultaneously dark matter and the baryon asymmetry in
the universe. In our set-up we introduce a dark sector, namely a non-Abelian
SU(2) hidden sector coupled to the SM via the Higgs portal, and a singlet
sector responsible for generating Majorana masses for three right-handed
sterile neutrinos. The gauge bosons of the dark sector are mass-degenerate and
stable, and this makes them suitable as dark matter candidates. Our model also
accounts for the matter-anti-matter asymmetry. The lepton flavour asymmetry is
produced during CP-violating oscillations of the GeV-scale right-handed
neutrinos, and converted to the baryon asymmetry by the electroweak sphalerons.
All the characteristic scales in the model: the electro-weak, dark matter and
the leptogenesis/neutrino mass scales, are generated radiatively, have a common
origin and related to each other via scalar field couplings in perturbation
theory.


title: Pseudo-functors modelling higher structures

abstract:
  We introduce a new higher categorical structure called a weakly globular
n-fold category. This structure is based on iterated internal categories and on
the notion of weak globularity. We identify a suitable class of pseudo-functors
whose strictification produces weakly globular n-fold categories.


title:
Zeros of random linear combinations of entire functions with complex
  Gaussian coefficients

abstract:
  We study zero distribution of random linear combinations of the form
$$P_n(z)=\sum_{j=0}^n\eta_jf_j(z),$$ in any Jordan region $\Omega \subset
\mathbb C$. The basis functions $f_j$ are entire functions that are real-valued
on the real line, and $\eta_0,\dots,\eta_n$ are complex-valued iid Gaussian
random variables. We derive an explicit intensity function for the number of
zeros of $P_n$ in $\Omega$ for each fixed $n$. Our main application is to
polynomials orthogonal on the real line. Using the Christoffel-Darboux formula
the intensity function takes a very simple shape. Moreover, we give the
limiting value of the intensity function when the orthogonal polynomials are
associated to Szeg\H{o} weights.


title: Functional Mapping of Multiple Dynamic Traits

abstract:
  Many biological phenomena undergo developmental changes in time and space.
Functional mapping, which is aimed at mapping genes that affect developmental
patterns, is instrumental for studying the genetic architecture of biological
changes. Often biological processes are mediated by a network of developmental
and physiological components and, therefore, are better described by multiple
phenotypes. In this article, we develop a multivariate model for functional
mapping that can detect and characterize quantitative trait loci (QTLs) that
simultaneously control multiple dynamic traits. Because the true genotypes of
QTLs are unknown, the measurements for the multiple dynamic traits are modeled
using a mixture distribution. The functional means of the multiple dynamic
traits are estimated using the nonparametric regression method, which avoids
any parametric assumption on the functional means. We propose the profile
likelihood method to estimate the mixture model. A likelihood ratio test is
exploited to test for the existence of pleiotropic effects on distinct but
developmentally correlated traits. A simulation study is implemented to
illustrate the finite sample performance of our proposed method. We also
demonstrate our method by identifying QTLs that simultaneously control three
dynamic traits of soybeans. The three dynamic traits are the time-course
biomass of the leaf, the stem, and the root of the whole soybean. The genetic
linkage map is constructed with 950 microsatellite markers. The new model can
aid in our comprehension of the genetic control mechanisms of complex dynamic
traits over time.


title:
Causality on Longitudinal Data: Stable Specification Search in
  Constrained Structural Equation Modeling

abstract:
  A typical problem in causal modeling is the instability of model structure
learning, i.e., small changes in finite data can result in completely different
optimal models. The present work introduces a novel causal modeling algorithm
for longitudinal data, that is robust for finite samples based on recent
advances in stability selection using subsampling and selection algorithms. Our
approach uses exploratory search but allows incorporation of prior knowledge,
e.g., the absence of a particular causal relationship between two specific
variables. We represent causal relationships using structural equation models.
Models are scored along two objectives: the model fit and the model complexity.
Since both objectives are often conflicting we apply a multi-objective
evolutionary algorithm to search for Pareto optimal models. To handle the
instability of small finite data samples, we repeatedly subsample the data and
select those substructures (from the optimal models) that are both stable and
parsimonious. These substructures can be visualized through a causal graph. Our
more exploratory approach achieves at least comparable performance as, but
often a significant improvement over state-of-the-art alternative approaches on
a simulated data set with a known ground truth. We also present the results of
our method on three real-world longitudinal data sets on chronic fatigue
syndrome, Alzheimer disease, and chronic kidney disease. The findings obtained
with our approach are generally in line with results from more
hypothesis-driven analyses in earlier studies and suggest some novel
relationships that deserve further research.


title: Geometric inequalities on Heisenberg groups

abstract:
  We establish geometric inequalities in the sub-Riemannian setting of the
Heisenberg group $\mathbb H^n$. Our results include a natural sub-Riemannian
version of the celebrated curvature-dimension condition of Lott-Villani and
Sturm and also a geodesic version of the Borell-Brascamp-Lieb inequality akin
to the one obtained by Cordero-Erausquin, McCann and Schmuckenschl\"ager. The
latter statement implies sub-Riemannian versions of the geodesic
Pr\'ekopa-Leindler and Brunn-Minkowski inequalities. The proofs are based on
optimal mass transportation and Riemannian approximation of $\mathbb H^n$
developed by Ambrosio and Rigot. These results refute a general point of view,
according to which no geometric inequalities can be derived by optimal mass
transportation on singular spaces.


title:
Asymptotic Eigenvalue Distribution of Wishart Matrices whose Components
  are not Independently and Identically Distributed

abstract:
  In the present work, eigenvalue distributions defined by a random rectangular
matrix whose components are neither independently nor identically distributed
are analyzed using replica analysis and belief propagation. In particular, we
consider the case in which the components are independently but not identically
distributed; for example, only the components in each row or in each column may
be {identically distributed}. We also consider the more general case in which
the components are correlated with one another. We use the replica approach
while making only weak assumptions in order to determine the asymptotic
eigenvalue distribution and to derive an algorithm for doing so, based on
belief propagation. One of our findings supports the results obtained from
Feynman diagrams. We present the results of several numerical experiments that
validate our proposed methods.

categories: q-fin.PM cond-mat.dis-nn math-ph math.MP


title: Nonlinear echoes and Landau damping with insufficient regularity

abstract:
  We prove that the theorem of Mouhot and Villani on Landau damping near
equilibrium for the Vlasov-Poisson equations on $\mathbb{T}_x \times
\mathbb{R}_v$ cannot, in general, be extended to high Sobolev spaces in the
case of gravitational interactions. This is done by showing in every Sobolev
space, there exists background distributions such that one can construct
arbitrarily small perturbations that exhibit arbitrarily many isolated
nonlinear oscillations in the density. These oscillations are known as plasma
echoes in the physics community. For the case of electrostatic interactions, we
demonstrate a sequence of small background distributions and asymptotically
smaller perturbations in $H^s$ which display similar nonlinear echoes. This
shows that in the electrostatic case, any extension of Mouhot and Villani's
theorem to Sobolev spaces would have to depend crucially on some additional
non-resonance effect coming from the background -- unlike the case of
Gevrey-$\nu$ with $\nu < 3$ regularity, for which results are uniform in the
size of small backgrounds. In particular, the uniform dependence on small
background distributions obtained in Mouhot and Villani's theorem in Gevrey
class is false in Sobolev spaces.


title:
Effects of critical fluctuations and dimensionality on the jump in
  specific heat at the superconducting transition temperature: Application to
  YBa2Cu_3 O_7 - \delta, Bi_2 Sr_2CaCu_2 O_8+\delta and KOs_2 O_6 compounds

abstract:
  We report on a study of the superconducting order parameter thermodynamic
fluctuations in $\mathrm{YBa}_2\mathrm{Cu}_3\mathrm{O}_{7 - \delta}$,
$\mathrm{Bi}_{2}\mathrm{Sr}_{2}\mathrm{CaCu}_{2}\mathrm{O}_{8+ \delta}$ and
$\mathrm{KOs}_2\mathrm{O}_6$ compounds. A non-perturbative technique within the
framework of the renormalized Gaussian approach is proposed. The essential
features are reported (analytically and numerically) through Ginzburg-Landau
(GL) model-based calculations which take into account both the dimension and
the microscopic parameters of the system. By presenting a self-consistent
approach (SCA) improvement on the GL theory, a technique for obtaining
corrections to the asymptotic critical behavior in terms of non universal
parameters is developed. Therefore, corrections to the specific heat and the
critical transition temperature for one-, two- and three-dimensional samples
are found taking into account the fact that fluctuations occur at all length
scales as the critical point of a system is approached. The GL model in the
free-field approximation and the 3D-XY model are suitable for describing the
weak and strong fluctuation regimes respectively. However, with a modified
quadratic coefficient, the renormalized GL model is able to explain certain
experimental observations including the specific heat of complicated systems,
such as the cuprate superconductors and the $\beta$-pyrochlore oxides. It is
clearly shown that the enhancement, suppression or rounding of the specific
heat jump of high-$T_c$ cuprate superconductors at the transition are
indicative of the order parameter thermodynamic fluctuations according to the
dimension and the nature of interactions.


title:
Portfolio Optimization Problem with Non-identical Variances of Asset
  Returns using Statistical Mechanical Informatics

abstract:
  The portfolio optimization problem in which the variances of the return rates
of assets are not identical is analyzed in this paper using the methodology of
statistical mechanical informatics, specifically, replica analysis. We define
two characteristic quantities of an optimal portfolio, namely, minimal
investment risk and concentrated investment level, in order to solve the
portfolio optimization problem and analytically determine their asymptotical
behaviors using replica analysis. Moreover, numerical experiments were
performed, and a comparison between the results of our simulation and those
obtained via replica analysis validated our proposed method.


title:
Information-Theoretic Lower Bounds on the Storage Cost of Shared Memory
  Emulation

abstract:
  The focus of this paper is to understand storage costs of emulating an atomic
shared memory over an asynchronous, distributed message passing system.
Previous literature has developed several shared memory emulation algorithms
based on replication and erasure coding techniques. In this paper, we present
information-theoretic lower bounds on the storage costs incurred by shared
memory emulation algorithms. Our storage cost lower bounds are universally
applicable, that is, we make no assumption on the structure of the algorithm or
the method of encoding the data.
  We consider an arbitrary algorithm $A$ that implements an atomic multi-writer
single-reader (MWSR) shared memory variable whose values come from a finite set
$\mathcal{V}$ over a system of $N$ servers connected by point-to-point
asynchronous links. We require that in every fair execution of algorithm $A$
where the number of server failures is smaller than a parameter $f$, every
operation invoked at a non-failing client terminates. We define the storage
cost of a server in algorithm $A$ as the logarithm (to base 2) of number of
states it can take on; the total-storage cost of algorithm $A$ is the sum of
the storage cost of all servers.
  Our results are as follows. (i) We show that if algorithm $A$ does not use
server gossip, then the total storage cost is lower bounded by $2
\frac{N}{N-f+1}\log_2|\mathcal{V}|-o(\log_2|\mathcal{V}|)$. (ii) The total
storage cost is at least $2 \frac{N}{N-f+2}
\log_{2}|\mathcal{V}|-o(\log_{2}|\mathcal{V}|)$ even if the algorithm uses
server gossip. (iii) We consider algorithms where the write protocol sends
information about the value in at most one phase. We show that the total
storage cost is at least $\nu^* \frac{N}{N-f+\nu^*-1} \log_2( |\mathcal{V}|)-
o(\log_2(|\mathcal{V}|),$ where $\nu^*$ is the minimum of $f+1$ and the number
of active write operations of an execution.


title:
Minimal Investment Risk of Portfolio Optimization Problem with Budget
  and Investment Concentration Constraints

abstract:
  In the present paper, the minimal investment risk for a portfolio
optimization problem with imposed budget and investment concentration
constraints is considered using replica analysis. Since the minimal investment
risk is influenced by the investment concentration constraint (as well as the
budget constraint), it is intuitive that the minimal investment risk for the
problem with an investment concentration constraint be larger than that without
the constraint (that is, with only the budget constraint). Moreover, a
numerical experiment shows the effectiveness of our proposed analysis.


title: Continuous perturbations of noncommutative Euclidean spaces and tori

abstract:
  We prove a noncompact version of Haagerup and R{\o}rdam's result about
continuous paths of the rotation $C^*$-algebras. It gives a continuous Moyal
deformation of Euclidean plane. Moveover, the construction is generalized to
noncommutative Euclidean spaces of dimension $d\ge 2$. As a corollary, we
obtain Lip$^{\frac12}$ continuous maps for the generators of noncommutative
$d$-tori.


title:
A simple construction of cover-free $(s,\ell)$-code with certain
  constant weight

abstract:
  We give a method of constructing a cover-free $(s, \ell)$-code. For $k > s$,
our construction yields a $ {{n \choose s} \choose \ell}\times {n \choose k}$
cover-free $(s, \ell)$-code with a constant column weight.


title: Nonnegative Matrix Factorization Requires Irrationality

abstract:
  Nonnegative matrix factorization (NMF) is the problem of decomposing a given
nonnegative $n \times m$ matrix $M$ into a product of a nonnegative $n \times
d$ matrix $W$ and a nonnegative $d \times m$ matrix $H$. A longstanding open
question, posed by Cohen and Rothblum in 1993, is whether a rational matrix $M$
always has an NMF of minimal inner dimension $d$ whose factors $W$ and $H$ are
also rational. We answer this question negatively, by exhibiting a matrix for
which $W$ and $H$ require irrational entries.


title:
A note on optimal expected utility of dividend payments with
  proportional reinsurance

abstract:
  In this paper, we consider the problem of maximizing the expected discounted
utility of dividend payments for an insurance company that controls risk
exposure by purchasing proportional reinsurance. We assume the preference of
the insurer is of CRRA form. By solving the corresponding
Hamilton-Jacobi-Bellman equation, we identify the value function and the
corresponding optimal strategy. We also analyze the asymptotic behavior of the
value function for large initial reserves. Finally, we provide some numerical
examples to illustrate the results and analyze the sensitivity of the
parameters.


title:
Many body quantum physics in XANES of highly correlated materials, mixed
  valence oxides and high temperature superconductors

abstract:
  The x-ray absorption near edge structure (XANES), developed in these last 40
years using synchrotron radiation, is a unique tool probing electronic
correlations in complex systems via quantum many body final state effects.
Multi electron excitations have been observed first in the sixties in x-ray
absorption spectra of atoms and later in molecules and solids. The applications
of XANES many body final states to probe unique features of electronic
correlation in heavy fermions, mixed valence systems, mixed valence oxides and
high temperature superconductors are discussed.


title: Generalized Nonlinear Yule Models

abstract:
  With the aim of considering models with persistent memory we propose a
fractional nonlinear modification of the classical Yule model often studied in
the context of macrovolution. Here the model is analyzed and interpreted in the
framework of the development of networks such as the World Wide Web.
Nonlinearity is introduced by replacing the linear birth process governing the
growth of the in-links of each specific webpage with a fractional nonlinear
birth process with completely general birth rates.
  Among the main results we derive the explicit distribution of the number of
in-links of a webpage chosen uniformly at random recognizing the contribution
to the asymptotics and the finite time correction. The mean value of the latter
distribution is also calculated explicitly in the most general case.
Furthermore, in order to show the usefulness of our results, we particularize
them in the case of specific birth rates giving rise to a saturating behaviour,
a property that is often observed in nature. The further specialization to the
non-fractional case allows us to extend the Yule model accounting for a
nonlinear growth.


title: The Greedy Spanner is Existentially Optimal

abstract:
  The greedy spanner is arguably the simplest and most well-studied spanner
construction. Experimental results demonstrate that it is at least as good as
any other spanner construction, in terms of both the size and weight
parameters. However, a rigorous proof for this statement has remained elusive.
  In this work we fill in the theoretical gap via a surprisingly simple
observation: The greedy spanner is \emph{existentially optimal} (or
existentially near-optimal) for several important graph families, in terms of
both the size and weight. Roughly speaking, the greedy spanner is said to be
existentially optimal (or near-optimal) for a graph family $\mathcal G$ if the
worst performance of the greedy spanner over all graphs in $\mathcal G$ is just
as good (or nearly as good) as the worst performance of an optimal spanner over
all graphs in $\mathcal G$.
  Focusing on the weight parameter, the state-of-the-art spanner constructions
for both general graphs (due to Chechik and Wulff-Nilsen [SODA'16]) and
doubling metrics (due to Gottlieb [FOCS'15]) are complex. Plugging our
observation on these results, we conclude that the greedy spanner achieves
near-optimal weight guarantees for both general graphs and doubling metrics,
thus resolving two longstanding conjectures in the area.
  Further, we observe that approximate-greedy spanners are existentially
near-optimal as well. Consequently, we provide an $O(n \log n)$-time
construction of $(1+\epsilon)$-spanners for doubling metrics with constant
lightness and degree. Our construction improves Gottlieb's construction, whose
runtime is $O(n \log^2 n)$ and whose number of edges and degree are unbounded,
and remarkably, it matches the state-of-the-art Euclidean result (due to
Gudmundsson et al.\ [SICOMP'02]) in all the involved parameters (up to
dependencies on $\epsilon$ and the dimension).


title: Path Planning in Dynamic Environments with Adaptive Dimensionality

abstract:
  Path planning in the presence of dynamic obstacles is a challenging problem
due to the added time dimension in search space. In approaches that ignore the
time dimension and treat dynamic obstacles as static, frequent re-planning is
unavoidable as the obstacles move, and their solutions are generally
sub-optimal and can be incomplete. To achieve both optimality and completeness,
it is necessary to consider the time dimension during planning. The notion of
adaptive dimensionality has been successfully used in high-dimensional motion
planning such as manipulation of robot arms, but has not been used in the
context of path planning in dynamic environments. In this paper, we apply the
idea of adaptive dimensionality to speed up path planning in dynamic
environments for a robot with no assumptions on its dynamic model.
Specifically, our approach considers the time dimension only in those regions
of the environment where a potential collision may occur, and plans in a
low-dimensional state-space elsewhere. We show that our approach is complete
and is guaranteed to find a solution, if one exists, within a cost
sub-optimality bound. We experimentally validate our method on the problem of
3D vehicle navigation (x, y, heading) in dynamic environments. Our results show
that the presented approach achieves substantial speedups in planning time over
4D heuristic-based A*, especially when the resulting plan deviates
significantly from the one suggested by the heuristic.


title:
Macroscopic transverse drift of long current-induced spin coherence in
  two-dimensional electron gases

abstract:
  We imaged the transport of current-induced spin coherence in a
two-dimensional electron gas confined in a triple quantum well. Nonlocal Kerr
rotation measurements, based on the optical resonant amplification of the
electrically-induced polarization, revealed a large spatial variation of the
electron g factor and the efficient generation of a current controlled
spin-orbit field in a macroscopic Hall bar device. We observed coherence times
in the nanoseconds range transported beyond half-millimeter distances in a
direction transverse to the applied electric field. The measured long spin
transport length can be explained by two material properties: large mean free
path for charge diffusion in clean systems and enhanced spin-orbit coefficients
in the triple well.


title: Smart broadcasting: Do you want to be seen?

abstract:
  Many users in online social networks are constantly trying to gain attention
from their followers by broadcasting posts to them. These broadcasters are
likely to gain greater attention if their posts can remain visible for a longer
period of time among their followers' most recent feeds. Then when to post? In
this paper, we study the problem of smart broadcasting using the framework of
temporal point processes, where we model users feeds and posts as discrete
events occurring in continuous time. Based on such continuous-time model, then
choosing a broadcasting strategy for a user becomes a problem of designing the
conditional intensity of her posting events. We derive a novel formula which
links this conditional intensity with the visibility of the user in her
followers' feeds. Furthermore, by exploiting this formula, we develop an
efficient convex optimization framework for the when-to-post problem. Our
method can find broadcasting strategies that reach a desired visibility level
with provable guarantees. We experimented with data gathered from Twitter, and
show that our framework can consistently make broadcasters' post more visible
than alternatives.


title:
Orion: Enabling Suggestions in a Visual Query Builder for
  Ultra-Heterogeneous Graphs

abstract:
  The database community has long recognized the importance of graphical query
interface to the usability of data management systems. Yet, relatively less has
been done. We present Orion, a visual interface for querying
ultra-heterogeneous graphs. It iteratively assists users in query graph
construction by making suggestions via machine learning methods. In its active
mode, Orion automatically suggests top-k edges to be added to a query graph. In
its passive mode, the user adds a new edge manually, and Orion suggests a
ranked list of labels for the edge. Orion's edge ranking algorithm, Random
Decision Paths (RDP), makes use of a query log to rank candidate edges by how
likely they will match the user's query intent. Extensive user studies using
Freebase demonstrated that Orion users have a 70% success rate in constructing
complex query graphs, a significant improvement over the 58% success rate by
the users of a baseline system that resembles existing visual query builders.
Furthermore, using active mode only, the RDP algorithm was compared with
several methods adapting other machine learning algorithms such as random
forests and naive Bayes classifier, as well as class association rules and
recommendation systems based on singular value decomposition. On average, RDP
required 40 suggestions to correctly reach a target query graph (using only its
active mode of suggestion) while other methods required 1.5--4 times as many
suggestions.


title: Finding the Year's Share in Day-of-Week Calculations

abstract:
  The dominant part in the mental calculation of the day of the week for any
given date is to determine the year share, that is, the contribution of the
two-digit year part of the date. This paper describes a number of year share
computation methods, some well-known and some new. The "Parity Minus 3" method,
in particular, is a new alternative to the popular "Odd+11" method. The paper
categorizes the methods of year share computation, and presents simpler proofs
of their correctness than usually provided.
  Keywords and phrases: day of the week, calendar algorithms, doomsday method,
first Sunday algorithm, mental arithmetic, year share


title:
Effect of extended confinement on the structure of edge channels in the
  quantum anomalous Hall effect

abstract:
  Quantum anomalous Hall (QAH) effect in the films with nontrivial band
structure accompanies the ferromagnetic transition in the system of magnetic
dopants. Experimentally, the QAH transition manifests itself as a jump in the
dependence of longitudinal resistivity on a weak external magnetic field.
Microscopically, this jump originates from the emergence of a chiral edge mode
on one side of the ferromagnetic transition. We study analytically the effect
of an extended confinement on the structure of the edge modes. We employ the
simplest model of the extended confinement in the form of potential step next
to the hard wall. It is shown that, unlike the conventional quantum Hall
effect, where all edge channels are chiral, in QAH effect, a complex structure
of the boundary leads to nonchiral edge modes which are present on both sides
of the ferromagnetic transition. Wave functions of nonchiral modes are
different above and below the transition: on the "topological" side, where the
chiral edge mode is supported, nonchiral modes are "repelled" from the
boundary, i.e. they are much less localized than on the "trivial" side. Thus,
the disorder-induced scattering into these modes will boost the extension of
the chiral edge mode. The prime experimental manifestation of nonchiral modes
is that, by contributing to longitudinal resistance, they smear the QAH
transition.