title:
Development of an Interatomic Potential for the Simulation of Defects,
  Plasticity and Phase Transformations in Titanium

abstract:
  New interatomic potentials describing defects, plasticity and high
temperature phase transitions for Ti are presented. Fitting the martensitic
hcp-bcc phase transformation temperature requires an efficient and accurate
method to determine it. We apply a molecular dynamics (MD) method based on
determination of the melting temperature of competing solid phases, and
Gibbs-Helmholtz integration, and a lattice-switch Monte Carlo method (LSMC):
these agree on the hcp-bcc transformation temperatures to within 2 K. We were
able to develop embedded atom potentials which give a good fit to either low or
high temperature data, but not both. The first developed potential (Ti1)
reproduces the hcp-bcc transformation and melting temperatures and is suitable
for the simulation of phase transitions and bcc Ti. Two other potentials (Ti2
and Ti3) correctly describe defect properties, and can be used to simulate
plasticity or radiation damage in hcp Ti. The fact that a single EAM potential
cannot describe both low and high temperature phases may be attributed to
neglect of electronic degrees of freedom, notably bcc has a much higher
electronic entropy. A temperature-dependent potential obtained from the
combination of potentials Ti1 and Ti2 may be used to simulate Ti properties at
any temperature.


title:
Chromospheric activity on the late-type star V1355 Ori using Lijiang
  1.8-m and 2.4-m telescopes

abstract:
  We obtained new high-resolution spectra using the Lijiang 1.8-m and 2.4-m
telescopes to investigate the chromospheric activities of V1355 Ori as
indicated in the behaviors of Ca ii H&K, Hdelta, Hgamma, Hbeta, Na i D1, D2,
Halpha and Ca ii infrared triplet (IRT) lines. The observed spectra show
obvious emissions above the continuum in Ca ii H&K lines, absorptions in the
Hdelta, Hgamma, Hbeta and Na i D1, D2 lines, variable behavior (filled-in
absorption, partial emission with a core absorption component or emission above
the continuum) in the Halpha line, and weak self-reversal emissions in the
strong filled-in absorptions of the Ca ii IRT lines. We used a spectral
subtraction technique to analyze our data. The results show no excess emission
in the Hdelta and Hgamma lines, very weak excess emissions in the Na i D1, D2
lines, excess emission in the Hbeta line, clear excess emission in the Halpha
line, and excess emissions in the Ca ii IRT lines. The value of the ratio of
EW8542/EW8498 is in the range 0.9 to 1.7, which implies that chromospheric
activity might have been caused by plage events. The value of the ratio E
Halpha/E Hbeta is above 3, indicating that the Balmer lines would arise from
prominence-like material. We also found time variations in light curves
associated with equivalent widths of chromospheric activity lines in the Na i
D1, D2, Ca ii IRT and Halpha lines in particular. These phenomena can be
explained by plage events, which are consistent with the behavior of
chromospheric activity indicators.


title: Patterns of Linguistic Diffusion in Space and Time: The Case of Mazatec

abstract:
  In the framework of complexity theory, which provides a unified framework for
natural and social sciences, we study the complex and interesting problem of
the internal structure, similarities, and differences between the Mazatec
dialects, an endangered Otomanguean language spoken in south-east Mexico. The
analysis is based on some databases, which are used to compute linguistic
distances between the dialects. The results are interpreted in the light of
linguistics as well as statistical considerations and used to infer the history
of the development of the observed pattern of diversity.


title:
The population of hot subdwarf stars studied with Gaia I. The catalogue
  of known hot subdwarf stars

abstract:
  In preparation for the upcoming all-sky data releases of the Gaia mission we
compiled a catalogue of known hot subdwarf stars and candidates drawn from the
literature and yet unpublished databases. The catalogue contains 5613 unique
sources and provides multi-band photometry from the ultraviolet to the far
infrared, ground based proper motions, classifications based on spectroscopy
and colours, published atmospheric parameters, radial velocities and light
curve variability information. Using several different techniques we removed
outliers and misclassified objects. By matching this catalogue with astrometric
and photometric data from the Gaia mission, we will develop selection criteria
to construct a homogeneous, magnitude-limited all-sky catalogue of hot subdwarf
stars based on Gaia data.


title:
Exploring Interacting Topological Insulators with Ultracold Atoms: the
  Synthetic Creutz-Hubbard Model

abstract:
  Understanding the robustness of topological phases of matter in the presence
of strong interactions, and synthesising novel strongly-correlated topological
materials, lie among the most important and difficult challenges of modern
theoretical and experimental physics. In this work, we present a complete
theoretical analysis of the synthetic Creutz-Hubbard ladder, which is a
paradigmatic model that provides a neat playground to address these challenges.
We put special attention to the competition of correlated topological phases
and orbital quantum magnetism in the regime of strong interactions. These
results are furthermore confirmed and extended by extensive numerical
simulations. Moreover we propose how to experimentally realize this model in a
synthetic ladder, made of two internal states of ultracold fermionic atoms in a
one-dimensional optical lattice. Our work paves the way towards quantum
simulators of interacting topological insulators with cold atoms.


title:
Reconstruction and Selection of Single Top + Higgs to
  $\mathrm{b}\overline{\mathrm{b}}$ events at CMS in pp Collisions at
  $\sqrt{s}$ = 13 TeV

abstract:
  The associated production of a single top quark together with a Higgs boson
at the LHC can be used to lift the degeneracy regarding the sign of the top
quark Yukawa coupling. Therefore, t-channel and tW-channel production where the
Higgs boson is decaying into a $\mathrm{b}\overline{\mathrm{b}}$ pair is
inspected. Boosted decision trees are used to assign jets to the quarks in the
final state and classify the events. To maximize the separation between the
signal and the dominating $\mathrm{t}\overline{\mathrm{t}}$ background each
event is reconstructed under a signal and a $\mathrm{t}\overline{\mathrm{t}}$
hypothesis. The poster focuses on the event selection and the reconstruction of
events.


title:
Effective Theory of Non-Adiabatic Quantum Evolution Based on the Quantum
  Geometric Tensor

abstract:
  We study the role of the quantum geometric tensor (QGT) in the evolution of
quantum systems. We show that all its components play an important role on the
extra phase acquired by a spinor and on the trajectory of an accelerated
wavepacket in any realistic finite-duration experiment. While the adiabatic
phase is determined by the Berry curvature (the imaginary part of the tensor),
the non-adiabaticity is determined by the quantum metric (the real part of the
tensor) and allows to determine corrections in the regimes where Landau-Zener
approach is inapplicable. The particular case of a planar microcavity in the
strong coupling regime allows to extract the QGT components by direct light
polarization measurements and to check their effects on the quantum evolution.


title:
Mixed-order phase transition of the contact process near multiple
  junctions

abstract:
  We have studied the phase transition of the contact process near a multiple
junction of $M$ semi-infinite chains by Monte Carlo simulations. As opposed to
the continuous transitions of the translationally invariant ($M=2$) and
semi-infinite ($M=1$) system, the local order parameter is found to be
discontinuous for $M>2$. Furthermore, the temporal correlation length diverges
algebraically as the critical point is approached, but with different exponents
on the two sides of the transition. In the active phase, the estimate is
compatible with the bulk value, while in the inactive phase it exceeds the bulk
value and increases with $M$. The unusual local critical behavior is explained
by a scaling theory with an irrelevant variable, which becomes dangerous in the
inactive phase. Quenched spatial disorder is found to make the transition
continuous in agreement with earlier renormalization group results.


title:
Keep Your Nice Friends Close, but Your Rich Friends Closer --
  Computation Offloading Using NFC

abstract:
  The increasing complexity of smartphone applications and services necessitate
high battery consumption but the growth of smartphones' battery capacity is not
keeping pace with these increasing power demands. To overcome this problem,
researchers gave birth to the Mobile Cloud Computing (MCC) research area. In
this paper we advance on previous ideas, by proposing and implementing the
first known Near Field Communication (NFC)-based computation offloading
framework. This research is motivated by the advantages of NFC's short distance
communication, with its better security, and its low battery consumption. We
design a new NFC communication protocol that overcomes the limitations of the
default protocol; removing the need for constant user interaction, the one-way
communication restraint, and the limit on low data size transfer. We present
experimental results of the energy consumption and the time duration of two
computationally intensive representative applications: (i) RSA key generation
and encryption, and (ii) gaming/puzzles. We show that when the helper device is
more powerful than the device offloading the computations, the execution time
of the tasks is reduced. Finally, we show that devices that offload application
parts considerably reduce their energy consumption due to the low-power NFC
interface and the benefits of offloading.


title:
Interactions between pi-conjugated chromophores in a giant molecular
  spoked wheel

abstract:
  We discuss the intriguing photophysics of a giant molecular spoked wheel of
pi-conjugated arylenealkynylene chromophores on the single-molecule level. This
"molecular mesoscopic" tructure, C1878H2682, shows fast switching between the
12 identical chromophores since the fluorescence is unpolarised but only one
chromophore emits at a time.


title: Momentum conserving defects in affine Toda field theories

abstract:
  Type II integrable defects with more than one degree of freedom at the defect
are investigated. A condition on the form of the Lagrangian for such defects is
found which ensures the existence of a conserved momentum in the presence of
the defect. In addition it is shown that for any Lagrangian satisfying this
condition, the defect equations of motion, when taken to hold everywhere, can
be extended to give a B\"{a}cklund transformation between the bulk theories on
either side of the defect. This strongly suggests that such systems are
integrable. Momentum conserving defects and B\"{a}cklund transformations for
affine Toda field theories based on the $A_n$, $B_n$, $C_n$ and $D_n$ series of
Lie algebras are found. The defect associated with the $D_4$ affine Toda field
theory is examined in more detail. In particular classical time delays for
solitons passing through the defect are calculated.


title: Georges Lema\^itre: Life, Science and Legacy

abstract:
  This paper celebrates the remarkable life, science and legacy of Abb\'e
Georges Lema\^itre, the Belgian cleric and professor of physics; he was the
architect of the fireworks model for the origin of the universe. He died half a
century ago, three days after learning that Arno Penzias and Robert Wilson had
discovered the cosmic microwave background. Despite being gravely ill from
leukaemia, Lema\^itre lucidly praised this news, which confirmed the explosive
genesis of our universe.


title: Excitonic valley effects in monolayer WS$_2$ under high magnetic fields

abstract:
  Transition-metal dichalcogenides can be easily produced as atomically thin
sheets, exhibiting the possibility to optically polarize and read out the
valley pseudospin of extremely stable excitonic quasiparticles present in these
2D semiconductors. Here, we investigate a monolayer of tungsten disulphide in
high magnetic fields up to 30\,T via photoluminescence spectroscopy at low
temperatures. The valley degeneracy is lifted for all optical features,
particularly for excitons, singlet and triplet trions, for which we determine
the g factor separately. While the observation of a diamagnetic shift of the
exciton and trion resonances gives us insight into the real-space extension of
these quasiparticles, magnetic field induced valley polarization effects shed
light onto the exciton and trion dispersion relations in reciprocal space. The
field dependence of the trion valley polarizations is in line with the
predicted trion splitting into singlet and triplet configurations.


title: No domain left behind: is Let's Encrypt democratizing encryption?

abstract:
  The 2013 National Security Agency revelations of pervasive monitoring have
lead to an "encryption rush" across the computer and Internet industry. To push
back against massive surveillance and protect users privacy, vendors, hosting
and cloud providers have widely deployed encryption on their hardware,
communication links, and applications. As a consequence, the most of web
traffic nowadays is encrypted. However, there is still a significant part of
Internet traffic that is not encrypted. It has been argued that both costs and
complexity associated with obtaining and deploying X.509 certificates are major
barriers for widespread encryption, since these certificates are required to
established encrypted connections. To address these issues, the Electronic
Frontier Foundation, Mozilla Foundation, and the University of Michigan have
set up Let's Encrypt (LE), a certificate authority that provides both free
X.509 certificates and software that automates the deployment of these
certificates. In this paper, we investigate if LE has been successful in
democratizing encryption: we analyze certificate issuance in the first year of
LE and show from various perspectives that LE adoption has an upward trend and
it is in fact being successful in covering the lower-cost end of the hosting
market.


title:
Out of the dark and into the light: towards dark-state based chemical
  sensors

abstract:
  The rapidly increasing use of sensors throughout different research
disciplines and the demand for more efficient devices with less power
consumption depends critically on the emergence of new sensor materials and
novel sensor concepts. Atomically thin transition metal dichalcogenides have a
huge potential for sensor development within a wide range of applications.
Their optimal surface-to-volume ratio combined with strong light-matter
interaction results in a high sensitivity to changes in their surrounding.
Here, we present a novel, highly efficient sensing mechanism to detect
molecules based on dark excitons in these materials. We show that the presence
of molecules with a dipole moment transforms dark states into bright excitons
resulting in an additional pronounced peak in easy accessible optical spectra.
This effect exhibits a huge potential for sensor applications, since it offers
an unambiguous optical finger print for the detection of molecules - in
contrast to common sensing schemes relying on small peak shifts and intensity
changes.


title:
A coupled ligand-receptor bulk-surface system on a moving domain: well
  posedness, regularity and convergence to equilibrium

abstract:
  We prove existence, uniqueness, and regularity for a reaction-diffusion
system of coupled bulk-surface equations on a moving domain modelling
receptor-ligand dynamics in cells. The nonlinear coupling between the three
unknowns is through the Robin boundary condition for the bulk quantity and the
right hand sides of the two surface equations. Our results are new even in the
non-moving setting, and in this case we also show exponential convergence to a
steady state. The primary complications in the analysis are indeed the
nonlinear coupling and the Robin boundary condition. For the well posedness and
essential boundedness of solutions we use several De Giorgi-type arguments, and
we also develop some useful estimates to allow us to apply a Steklov averaging
technique for time-dependent operators to prove that solutions are strong. Some
of these auxiliary results presented in this paper are of independent interest
by themselves.


title: Efficient photochemistry of coronene: water complexes

abstract:
  The photochemistry of ices with polycyclic aromatic hydrocarbons (PAHs) has
been extensively studied, but to date no investigation has been made of PAHs in
interaction with low numbers (n < 4) of molecules of water. We performed
photochemical matrix isolation studies of coronene:water complexes, probing the
argon matrix with FTIR spectroscopy. We find that coronene readily reacts with
water upon irradiation with a mercury vapour lamp to produce oxygenated PAH
photoproducts, and we postulate a reaction mechanism via a charge transfer
Rydberg state. This result suggests that oxygenated PAHs should be widely
observed in regions of the ISM with sufficiently high water abundances, for
example near the edges of molecular clouds where water molecules begin to form,
but before icy layers are observed, that is at AV <3. In order to explain the
low derived observational abundances of oxygenated PAHs, additional destruction
routes must be invoked.


title:
Probing emergent geometry through phase transitions in free vector and
  matrix models

abstract:
  Boundary correlation functions provide insight into the emergence of an
effective geometry in higher spin gravity duals of O(N) or U(N) symmetric field
theories. On a compact manifold, the singlet constraint leads to nontrivial
dynamics at finite temperature and large N phase transitions even at vanishing
't Hooft coupling. At low temperature, the leading behavior of boundary
two-point functions is consistent with propagation through a bulk thermal anti
de Sitter space. Above the phase transition, the two-point function shows
significant departure from thermal AdS space and the emergence of localized
black hole like objects in the bulk. In adjoint models, these objects appear at
length scales of order of the AdS radius, consistent with a Hawking-Page
transition, but in vector models they are parametrically larger than the AdS
scale. In low dimensions, we find another crossover at large distances beyond
which the correlation function again takes a thermal AdS form, albeit with a
temperature dependent normalization factor.


title: Drell-Yan hadron tensor: contour gauge and gluon propagator

abstract:
  We consider the gauge invariant Drell-Yan hadron tensor which includes the
standard and non-standard diagram contributions. The non-standard diagram
contribution is appeared owing to the complexity of the twist three
$B^V(x_1,x_2)$-function where the gluon pole manifests. We use the contour
gauge conception which allows us to fix easily the spurious uncertainties in
the gluon propagator. The contour gauge condition is generated by the
corresponding Wilson lines in both the standard and non-standard diagrams. We
demonstrate the substantial role of the non-standard diagram for forming of the
relevant contour in the Wilson path-ordered exponential that leads to the
spurious singularity fixing.


title:
Local correlation functions of arbitrary order for the Falicov-Kimball
  model

abstract:
  Local n-particle vertex functions represent the crucial ingredient for all
diagrammatic extensions of dynamical mean field theory (DMFT). Hitherto their
application has been restricted -with a few exceptions- to the n=2-particle
vertex while higher-order vertices have been neglected. In this paper we derive
a general analytical expression for the n-particle (one-particle reducible)
vertex of the Falicov-Kimball model (FKM). We observe that the magnitude of
such vertex functions itself strongly increases with the particle-number n. On
the other hand, their effect on generic Feynman diagrams remains rather
moderate due to the damping effect of the Green's functions present in such
diagrams. Nevertheless, they yield important contributions to the self-energy
corrections calculated in diagrammatic extensions of DMFT as we explicitly
demonstrate using the example of dual fermion (DF) calculations for the
two-dimensional FKM at quarter filling of stationary f-electrons where
corrections to the self-energy obtained from the three-particle vertex are
indeed comparable in magnitude to corresponding corrections stemming from the
two-particle vertex.


title:
Approximations of classes of generalized Poisson integrals by Fourier
  sums in metrics of spaces $L_{s}$

abstract:
  In metrics of spaces $L_{s}, \ 1\leq s\leq\infty$, we find asymptotic
equalities for upper bounds of approximations by Fourier sums on classes of
generalized Poisson integrals of periodic functions, which belong to unit ball
of space $L_{1}$.


title: Ornstein-Uhlenbeck Process with Fluctuating Damping

abstract:
  This paper studies Langevin equation with random damping due to
multiplicative noise and its solution. Two types of multiplicative noise,
namely the dichotomous noise and fractional Gaussian noise are considered.
Their solutions are obtained explicitly, with the expressions of the mean and
covariance determined explicitly. Properties of the mean and covariance of the
Ornstein-Uhlenbeck process with random damping, in particular the asymptotic
behavior, are studied. The effect of the multiplicative noise on the stability
property of the resulting processes is investigated.


title:
Improved WKB approximation for quantum tunneling: Application to heavy
  ion fusion

abstract:
  In this paper we revisit the one-dimensional tunneling problem. We consider
Kemble's approximation for the transmission coefficient. We show how this
approximation can be extended to above-barrier energies by performing the
analytical continuation of the radial coordinate to the complex plane. We
investigate the validity of this approximation by comparing their predictions
for the cross section and for the barrier distribution with the corresponding
quantum mechanical results. We find that the extended Kemble's approximation
reproduces the results of quantum mechanics with great accuracy.


title: Exploring Microtask Crowdsourcing as a Means of Fault Localization

abstract:
  Microtask crowdsourcing is the practice of breaking down an overarching task
to be performed into numerous, small, and quick microtasks that are distributed
to an unknown, large set of workers. Microtask crowdsourcing has shown
potential in other disciplines, but with only a handful of approaches explored
to date in software engineering, its potential in our field remains unclear. In
this paper, we explore how microtask crowdsourcing might serve as a means of
fault localization. We particularly take a first step in assessing whether a
crowd of workers can correctly locate known faults in a few lines of code (code
fragments) taken from different open source projects. Through Mechanical Turk,
we collected the answers of hundreds of workers to a pre-determined set of
template questions applied to the code fragments, with a replication factor of
twenty answers per question. Our findings show that a crowd can correctly
distinguish questions that cover lines of code that contain a fault from those
that do not. We also show that various filters can be applied to identify the
most effective subcrowds. Our findings also presented serious limitations in
terms of the proportion of lines of code selected for inspection and the cost
to collect answers. We describe the design of our experiment, discuss the
results, and provide an extensive analysis of different filters and their
effects in terms of speed, cost, and effectiveness. We conclude with a
discussion of limitations and possible future experiments toward more
full-fledged fault localization on a large scale involving more complex faults.


title:
Precision measurement and interpretation of inclusive $W^+$, $W^-$ and
  $Z/\gamma^*$ production cross sections with the ATLAS detector

abstract:
  High-precision measurements by the ATLAS Collaboration are presented of
inclusive $W^+\to\ell^+\nu$, $W^-\to\ell^-\bar{\nu}$ and
$Z/\gamma^*\to\ell\ell$ ($\ell=e,\mu$) Drell-Yan production cross sections at
the LHC. The data were collected in proton-proton collisions at $\sqrt{s} = 7$
TeV with an integrated luminosity of 4.6 fb$^{-1}$. Differential $W^+$ and
$W^-$ cross sections are measured in a lepton pseudorapidity range
$|\eta_{\ell}| = 2.5$. Differential $Z/\gamma^*$ cross sections are measured as
a function of the absolute dilepton rapidity, for $|y_{\ell\ell}| < 3.6$, for
three intervals of dilepton mass, $m_{\ell\ell}$, extending from 46 to 150 GeV.
The integrated and differential electron- and muon-channel cross sections are
combined and compared to theoretical predictions using recent sets of parton
distribution functions. The data, together with the final inclusive $e^{\pm}p$
scattering cross-section data from H1 and ZEUS, are interpreted in a
next-to-next-to-leading-order QCD analysis, and a new set of parton
distribution functions, ATLAS-epWZ16, is obtained. The ratio of
strange-to-light sea-quark densities in the proton is determined more
accurately than in previous determinations based on collider data only, and is
established to be close to unity in the sensitivity range of the data. A new
measurement of the CKM matrix element $|V_{cs}|$ is also provided.


title: Vertex Sparsification in Trees

abstract:
  Given an unweighted tree $T=(V,E)$ with terminals $K \subset V$, we show how
to obtain a $2$-quality vertex flow and cut sparsifier $H$ with $V_H = K$. We
prove that our result is essentially tight by providing a $2-o(1)$ lower-bound
on the quality of any cut sparsifier for stars. In addition we give improved
results for quasi-bipartite graphs. First, we show how to obtain a $2$-quality
flow sparsifier with $V_H = K$ for such graphs. We then consider the other
extreme and construct exact sparsifiers of size $O(2^{k})$, when the input
graph is unweighted.


title: Effects of tidal gravitational fields in clustering dark energy models

abstract:
  We extend a previous work by Reischke et al., 2016 by studying the effects of
tidal shear on clustering dark energy models within the framework of the
extended spherical collapse model and using the Zel'dovich approximation. As in
previous works on clustering dark energy, we assumed a vanishing effective
sound speed describing the perturbations in dark energy models. To be
self-consistent, our treatment is valid only on linear scales since we do not
intend to introduce any heuristic models. This approach makes the linear
overdensity $\delta_{\rm c}$ mass dependent and similarly to the case of smooth
dark energy, its effects are predominant at small masses and redshifts. Tidal
shear has effects of the order of percent or less, regardless of the model and
preserves a well known feature of clustering dark energy: When dark energy
perturbations are included, the models resemble better the $\Lambda$CDM
evolution of perturbations. We also showed that effects on the comoving number
density of halos are small and qualitatively and quantitatively in agreement
with what previously found for smooth dark energy models.


title:
Automatic Model Based Dataset Generation for Fast and Accurate Crop and
  Weeds Detection

abstract:
  Selective weeding is one of the key challenges in the field of agriculture
robotics. To accomplish this task, a farm robot should be able to accurately
detect plants and to distinguish them between crop and weeds. Most of the
promising state-of-the-art approaches make use of appearance-based models
trained on large annotated datasets. Unfortunately, creating large agricultural
datasets with pixel-level annotations is an extremely time consuming task,
actually penalizing the usage of data-driven techniques. In this paper, we face
this problem by proposing a novel and effective approach that aims to
dramatically minimize the human intervention needed to train the detection and
classification algorithms. The idea is to procedurally generate large synthetic
training datasets randomizing the key features of the target environment (i.e.,
crop and weed species, type of soil, light conditions). More specifically, by
tuning these model parameters, and exploiting a few real-world textures, it is
possible to render a large amount of realistic views of an artificial
agricultural scenario with no effort. The generated data can be directly used
to train the model or to supplement real-world images. We validate the proposed
methodology by using as testbed a modern deep learning based image segmentation
architecture. We compare the classification results obtained using both real
and synthetic images as training data. The reported results confirm the
effectiveness and the potentiality of our approach.


title:
Influence of intermixing at the Ta/CoFeB interface on spin Hall angle in
  Ta/CoFeB/MgO heterostructures

abstract:
  We investigate the spin Hall effect in perpendicularly magnetized
Ta/Co40Fe40B20/MgO trilayers with Ta underlayers thicker than the spin
diffusion length. The crystallographic structures of the Ta layer and Ta/CoFeB
interface are examined in detail using X-ray diffraction and transmission
electron microscopy. The thinnest Ta underlayer is amorphous, whereas for
thicker Ta layers a disoriented tetragonal beta-phase appears. Effective
spin-orbit torques are calculated based on harmonic Hall voltage measurements
performed in a temperature range between 15 and 300 K. To account for the
temperature dependence of damping-like and field-like torques, we extend the
spin diffusion model by including an additional contribution from the Ta/CoFeB
interface. Based on this approach, the temperature dependence of the spin Hall
angle in the Ta underlayer and at Ta/CoFeB interface are determined separately.
The results indicate an almost temperature-independent spin Hall angle of
theta_SH-N = -0.2 in Ta and a strongly temperature-dependent theta_SH-I for the
intermixed Ta/CoFeB interface.


title: A complete radical formula and 2-primal modules

abstract:
  We introduce a complete radical formula for modules over non-commutative
rings which is the equivalence of a radical formula in the setting of modules
defined over commutative rings.
  This gives a general frame work through which known results about modules
over commutative rings that satisfy the radical formula are retrieved. Examples
and properties of modules that satisfy the complete radical formula are given.
For instance, it is shown that a module that satisfies the complete radical
formula is completely semiprime if and only if it is a subdirect product of
completely prime modules. This generalizes a ring theoretical result: a ring is
reduced if and only if it is a subdirect product of domains. We settle in
affirmative a conjecture by Groenewald and the current author given in
\cite{2p} that a module over a 2-primal ring is 2-primal.
  More instances where 2-primal modules behave like modules over commutative
rings are given. This is in tandem with the behaviour of 2-primal rings of
exhibiting tendencies of commutative rings. We end with some questions about
the role of 2-primal rings in algebraic geometry.


title: Compact foliations with finite transverse LS category

abstract:
  We prove that if F is a foliation of a compact manifold M with all leaves
compact submanifolds, and the transverse saturated category of F is finite,
then the leaf space M/F is compact Hausdorff. The proof is surprisingly
delicate, and is based on some new observations about the geometry of compact
foliations. Colman proved in her 1998 doctoral thesis that the transverse
saturated category of a compact Hausdorff foliation is always finite, so we
obtain a new characterization of the compact Hausdorff foliations among the
compact foliations as those with finite transverse saturated category.


title: Finite temperature quantum field theory in the heat kernel method

abstract:
  The trace of the heat kernel in a (D+1)-dimensional Euclidean spacetime
(integer D > 1) is used to derive the free energy in finite temperature field
theory. The spacetime presents a D-dimensional compact space (domain) with a
(D-1)-dimensional boundary, and a closed dimension, whose volume is
proportional the Planck's inverse temperature. The thermal sum appears due to
topology of the closed Euclidean time. The obtained free energy in (3+1) and
(2+1) dimensions contain two contributions defined by the volume of a domain
and by the volume of the domain's boundary. This functional is finite and valid
for arbitrary values of the Planck's inverse temperature. The absolute zero of
thermodynamic temperature is forbidden topologically, and no universal low
temperature asymptotics of the free energy can exist.


title:
How strong a logistic damping can prevent blow-up for the minimal
  Keller-Segel chemotaxis system?

abstract:
  In this paper, we study the minimal Keller-Segel model with a logistic source
and obtain quantitative and qualitative descriptions of the competition between
logistic damping and other ingredient, especially, chemotactic aggregation to
guarantee boundedness and convergence. More specifically, we establish how
precisely strong a logistic source can prevent blow-up, and then we obtain an
explicit relationship between logistic damping and other ingredient,
especially, chemotactic aggregation so that convergences are ensured and their
respective convergence rates are explicitly calculated out. Known results in
the literature are completed and refined.
  Furthermore, our findings provide clues on how to produce blowup solutions
for KS chemotaxis models with logistic sources.


title: A quantum hybrid with a thin antenna at the vertex of a wedge

abstract:
  We study the spectrum, resonances and scattering matrix of a quantum
hamiltonian on a "hybrid surface" consisting of a half-line attached by its
endpoint to the vertex of a concave planar wedge. At the boundary of the wedge,
outside the vertex, Dirichlet boundary are imposed. The system is tunable by
varying the measure of the angle at the vertex.


title:
High repetition pump-and-probe photoemission spectroscopy based on a
  compact fiber laser system

abstract:
  The paper describes a time-resolved photoemission (TRPES) apparatus equipped
with a Yb-doped fiber laser system delivering 1.2-eV pump and 5.9-eV probe
pulses at the repetition rate of 95 MHz. Time and energy resolutions are 11.3
meV and ~310 fs, respectively; the latter is estimated by performing TRPES on a
highly oriented pyrolytic graphite (HOPG). The high repetition rate is suited
for achieving high signal-to-noise ratio in TRPES spectra, thereby facilitating
investigations of ultrafast electronic dynamics in the low pump fluence (p)
region. TRPES of polycrystalline bismuth (Bi) at p as low as 30 nJ/mm2 is
demonstrated. The laser source is compact and is docked to an existing TRPES
apparatus based on a 250-kHz Ti:sapphire laser system. The 95-MHz system is
less prone to space-charge broadening effects compared to the 250-kHz system,
which we explicitly show in a systematic probe-power dependency of the Fermi
cutoff of polycrystalline gold. We also describe that the TRPES response of an
oriented Bi(111)/HOPG sample is useful for fine-tuning the spatial overlap of
the pump and probe beams even when p is as low as 30 nJ/mm2.


title:
Geometric inequalities for manifolds with Ricci curvature in the Kato
  class

abstract:
  We obtain an Euclidean volume growth results for complete Riemannian
manifolds satisfying a Euclidean Sobolev inequality and a spectral type
condition on the Ricci curvature. We also obtain eigenvalue estimates, heat
kernel estimates, Betti number estimates for closed manifolds whose Ricci
curvature is controlled in the Kato class.


title: Positive sparse domination of variational Carleson operators

abstract:
  Due to its nonlocal nature, the $r$-variation norm Carleson operator $C_r$
does not yield to the sparse domination techniques of Lerner, Di Plinio and
Lerner, Lacey. We overcome this difficulty and prove that the dual form to
$C_r$ can be dominated by a positive sparse form involving $L^p$ averages. Our
result strengthens the $L^p$ estimates by Oberlin et. al. As a corollary, we
obtain quantitative weighted norm inequalities improving on previous results by
Do and Lacey. Our proof relies on the localized outer $L^p$-embeddings of Di
Plinio-Ou and Uraltsev.


title: The Poisson-Voronoi cell around an isolated nucleus

abstract:
  Consider a planar random point process made of the union of a point (the
origin) and of a Poisson point process with a uniform intensity outside a
deterministic set surrounding the origin. When the intensity goes to infinity,
we show that the Voronoi cell associated with the origin converges from above
to a deterministic convex set. We describe this set and give the asymptotics of
the expectation of its defect area, defect perimeter and number of vertices. On
the way, two intermediary questions are treated. First, we describe the mean
characteristics of the Poisson-Voronoi cell conditioned on containing a fixed
convex body around the origin and secondly, we show that the nucleus of such
cell converges to the Steiner point of the convex body. As in R\'enyi and
Sulanke's seminal papers on random convex hulls, the regularity of the convex
body has crucial importance. We deal with both the smooth and polygonal cases.
Techniques are based notably on accurate estimates of the area of the Voronoi
flower and of the support function of the cell containing the origin as well as
on an Efron-type relation.


title: Origin of CH+ in diffuse molecular clouds warm H2 and ion-neutral drift

abstract:
  This paper assesses the roles of the presence of warm H2, and the increased
formation rate due to the ion-neutral drift. We performed ideal MHD simulations
that include the heating and cooling of the multiphase ISM, and where we treat
dynamically the formation of H2. In a post-processing step we compute the
abundances of species at chemical equilibrium. We show that CH+ is efficiently
formed at the edge of clumps, in regions where the H2 fraction is low, but
nevertheless higher than its equilibrium value, and where the gas temperature
is high. We show that warm and out of equilibrium H2 increases the integrated
column densities of CH+ by one order of magnitude, up to values still 3-10
times lower than those observed in the diffuse ISM. We balance the Lorentz
force with the ion-neutral drag to estimate the ion-drift velocities (vd). We
find that the vd distribution peaks around 0.04 km s-1, and that high vd are
too rare to have a significant statistical impact on the abundances of CH+.
Compared to previous works, our multiphase simulations reduce the spread in vd,
and our self-consistent treatment of the ionisation leads to much reduced vd.
Nevertheless, our resolution study shows that this velocity distribution is not
converged: the ion-neutral drift has a higher impact on CH+ at higher
resolution. On the other hand, our ideal MHD simulations do not include
ambipolar diffusion, which would yield lower drift velocities. Within these
limitations, we conclude that warm H2 is a key ingredient in the efficient
formation of CH+ and that the ambipolar diffusion has very little influence on
the abundance of CH+, mainly due to the small drift velocities obtained.
However, we point out that small-scale processes and other non-thermal
processes not included in our MHD simulation may be of crucial importance, and
higher resolution studies with better controlled dissipation processes are
needed.


title:
Early exercise decision in American options with dividends, stochastic
  volatility and jumps

abstract:
  Using a fast numerical technique, we investigate a large database of investor
suboptimal non-exercise of short maturity American call options on
dividend-paying stocks listed on the Dow Jones. The correct modelling of the
discrete dividend is essential for a correct calculation of the early exercise
boundary as confirmed by theoretical insights. Pricing with stochastic
volatility and jumps instead of the Black-Scholes-Merton benchmark cuts by a
quarter the amount lost by investors through suboptimal exercise. The remaining
three quarters are largely unexplained by transaction fees and may be
interpreted as an opportunity cost for the investors to monitor optimal
exercise.


title: CoALP-Ty'16

abstract:
  This volume constitutes the pre-proceedings of the Workshop on Coalgebra,
Horn Clause Logic Programming and Types (CoALP-Ty'16), held on 28--29 November
2016 in Edinburgh as a mark of the end of the EPSRC Grant Coalgebraic Logic
Programming for Type Inference, by E. Komendantskaya and J. Power. This volume
consists of extended abstracts describing current research in the following
areas:
  Semantics: Lawvere theories and Coalgebra in Logic and Functional Programming
  Programming languages: Horn Clause Logic for Type Inference in Functional
Languages and Beyond
  After discussion at the workshop authors of the extended abstracts will be
invited to submit a full paper to go through a second round of refereeing and
selection for the formal proceedings.


title: Robust state preparation in quantum simulations of Dirac dynamics

abstract:
  A non-relativistic system such as an ultracold trapped ion may perform a
quantum simulation of a Dirac equation dynamics under specific conditions. The
resulting Hamiltonian and dynamics are highly controllable, but the coupling
between momentum and internal levels poses some difficulties to manipulate the
internal states accurately in wave packets. We use invariants of motion to
inverse engineer robust population inversion processes with a homogeneous,
time-dependent simulated electric field. This exemplifies the usefulness of
inverse-engineering techniques to improve the performance of quantum simulation
protocols.


title:
First test of Verlinde's theory of Emergent Gravity using Weak
  Gravitational Lensing measurements

abstract:
  Verlinde (2016) proposed that the observed excess gravity in galaxies and
clusters is the consequence of Emergent Gravity (EG). In this theory the
standard gravitational laws are modified on galactic and larger scales due to
the displacement of dark energy by baryonic matter. EG gives an estimate of the
excess gravity (described as an apparent dark matter density) in terms of the
baryonic mass distribution and the Hubble parameter. In this work we present
the first test of EG using weak gravitational lensing, within the regime of
validity of the current model. Although there is no direct description of
lensing and cosmology in EG yet, we can make a reasonable estimate of the
expected lensing signal of low redshift galaxies by assuming a background
LambdaCDM cosmology. We measure the (apparent) average surface mass density
profiles of 33,613 isolated central galaxies, and compare them to those
predicted by EG based on the galaxies' baryonic masses. To this end we employ
the ~180 square degrees overlap of the Kilo-Degree Survey (KiDS) with the
spectroscopic Galaxy And Mass Assembly (GAMA) survey. We find that the
prediction from EG, despite requiring no free parameters, is in good agreement
with the observed galaxy-galaxy lensing profiles in four different stellar mass
bins. Although this performance is remarkable, this study is only a first step.
Further advancements on both the theoretical framework and observational tests
of EG are needed before it can be considered a fully developed and solidly
tested theory.


title: Direct numerical simulation of water-ethanol flows in a T-mixer

abstract:
  The efficient mixing of fluids is key in many applications, such as chemical
reactions and nanoparticle precipitation. Detailed experimental measurements of
the mixing dynamics are however difficult to obtain, and so predictive
numerical tools are helpful in designing and optimizing many processes. If two
different fluids are considered, the viscosity and density of the mixture
depend often nonlinearly on the composition, which makes the modeling of the
mixing process particularly challenging. Hence water-water mixtures in simple
geometries such as T-mixers have been intensively investigated, but little is
known about the dynamics of more complex mixtures, especially in the turbulent
regime. We here present a numerical method allowing the accurate simulation of
two-fluid mixtures. Using a high-performance implementation of this method we
perform direct numerical simulations resolving the spatial and temporal
dynamics of water-ethanol flows for Reynolds numbers from 100 to 2000. The
flows states encountered during turbulence transition and their mixing
properties are discussed in detail and compared to water-water mixtures.


title:
Quantum Nonlinear Optics with a Germanium-Vacancy Color Center in a
  Nanoscale Diamond Waveguide

abstract:
  We demonstrate a quantum nanophotonics platform based on germanium-vacancy
(GeV) color centers in fiber-coupled diamond nanophotonic waveguides. We show
that GeV optical transitions have a high quantum efficiency and are nearly
lifetime-broadened in such nanophotonic structures. These properties yield an
efficient interface between waveguide photons and a single GeV without the use
of a cavity or slow-light waveguide. As a result, a single GeV center reduces
waveguide transmission by $18 \pm 1\%$ on resonance in a single pass. We use a
nanophotonic interferometer to perform homodyne detection of GeV resonance
fluorescence. By probing the photon statistics of the output field, we
demonstrate that the GeV-waveguide system is nonlinear at the single-photon
level.


title:
Impact of Sommerfeld enhancement on helium reionization via WIMP dark
  matter

abstract:
  Dark matter annihilation can have a strong impact on many astrophysical
processes in the Universe. In the case of Sommerfeld-enhanced annihilation
cross sections, the annihilation rates are enhanced at late times, thus
enhancing the potential annihilation signatures. We here calculate the
Sommerfeld-enhanced annihilation signatures during the epoch of helium
reionization, the epoch where helium becomes fully ionized due to energetic
photons. When considering the upper limits on the energy injection from the
CMB, we find that the resulting abundance of He$^{++}$ becomes independent of
the dark matter particle mass. The resulting enhancement compared to a standard
scenario is thus 1-2 orders of magnitude higher. For realistic scenarios
compatible with CMB constraints, there is no significant shift in the epoch of
helium reionization, which is completed between redshifts $3$ and $4$. While it
is thus difficult to disentangle dark matter annihilation from astrophysical
contributions (active galactic nuclei), a potential detection of dark matter
particles and its interactions using the Large Hadron Collider (LHC) would
allow one to quantify the dark matter contribution.


title:
Universal scaling of unequal-time correlation functions in ultracold
  Bose gases far from equilibrium

abstract:
  We explore the far-from-equilibrium dynamics of Bose gases in a universal
regime associated to nonthermal fixed points. While previous investigations
concentrated on scaling functions and exponents describing equal-time
correlations, we compute the additional scaling functions and dynamic exponent
$z$ characterizing the frequency dependence or dispersion from unequal-time
correlations. This allows us to compare the characteristic condensation and
correlation times from a finite-size scaling analysis depending on the system's
volume.


title:
Computer simulation study of the nematic-vapour interface in the
  Gay-Berne model

abstract:
  We present computer simulations of the vapour-nematic interface of the
Gay-Berne model. We considered situations which correspond to either prolate or
oblate molecules. We determine the anchoring of the nematic phase and correlate
it with the intermolecular potential parameters. On the other hand, we evaluate
the surface tension associated to this interface. We find a corresponding
states law for the surface tension dependence on the temperature, valid for
both prolate and oblate molecules.


title: A note on holographic dark energy with varying $c^2$ term

abstract:
  We reconsider the holographic dark energy (HDE) model with a slowly time
varying $ c^2(z)$ parameter in the energy density, namely $\rho_D=3M_p^2
c^2(z)/L^2$, where $L$ is the IR cutoff and $z$ is the redshift parameter. As
the system's IR cutoff we choose the Hubble radius and the Granda-Oliveros (GO)
cutoffs. The latter inspired by the Ricci scalar curvature. We derive the
evolution of the cosmological parameters such as the equation of state and the
deceleration parameters as the explicit functions of the redshift parameter
$z$. Then, we plot the evolutions of these cosmological parameters in terms of
the redshift parameter during the history of the universe. Interestingly
enough, we observe that by choosing $L=H^{-1}$ as the IR cutoff for the HDE
with time varying $ c ^2(z) $ term, the present acceleration of the universe
expansion can be achieved, even in the absence of interaction between dark
energy and dark matter. This is in contrast to the usual HDE model with
constant $c^2$ term, which leads to a wrong equation of state, namely that for
dust $w_D=0$, when the IR cutoff is chosen the Hubble radius.


title:
Surface energy coefficient determination in global mass formula from
  fission barrier energy

abstract:
  Semi-empirical mass formula of the atomic nucleus describe binding energies
of the nuclei. In the simple form of this formula, there are five terms related
to the properties of the nuclear structure. The coefficients in each terms can
be determined by various approach such as fitting on experimental binding
energy values. In this study, the surface energy coefficient in the formula
which is a correction on total binding energy has been obtained by a method
that is not previously described in the literature. The experimental fission
barrier energies of nuclei have been used for this task. According to the
results, surface energy coefficient in one of the most conventional formula has
been improved by a factor 3.4.


title:
Analyzing the Synergy between Broadcast Polling and Piggybacking in
  WiMAX Networks

abstract:
  In this work we present a model for analyzing the combined use of broadcast
polling and piggybacking in Worldwide Interoperability for Microwave Access
(WiMAX) networks. For an accurate analysis of piggybacking, the model focuses
on the realistic case of limited up-link bandwidth and non-trivial queueing
capability at the subscriber stations. We first model the activity of a
subscriber station using a Markov chain and its queue as an M/G/1 system with
vacations in order to facilitate the analysis of the piggyback mechanism. We
then derive a set of fixed point equations that describe not only the
contention process at the network level but also bandwidth allocation to
contending and piggybacked requests. Our model uses a minimal set of
assumptions and is generic in the sense that it is customizable through a set
of parameters. It can also reproduce the system performance in both saturated
and non-saturated conditions. After validating our analysis through extensive
simulations, we shed light on the aspects of the synergy between broadcast
polling and piggybacking and unveil the pros and cons of using the latter.


title:
The relation between quenched and annealed Lyapunov exponents in random
  potential on trees

abstract:
  In the first part of the article our subject of interest is a simple
symmetric random walk on the integers which faces a random risk to be killed.
This risk is described by random potentials, which in turn are defined by a
sequence of independent and identically distributed non-negative random
variables. To determine the risk of taking a walk in these potentials we
consider the decay of the Green function. There are two possible tools to
describe this decay: The quenched Lyapunov exponents and the annealed Lyapunov
exponents. It turns out that on the integers we can state a precise relation
between these two. The main tool for proving this is due to a special path
property on the integers: if the random walk travels from one point to another
one in finite time all the points between have to be passed in finite time as
well. This allows using Ergodic Theorems. In the second part we show that the
relation is also true in the case of Lyapunov exponents for simple symmetric
random walks on d-regular trees and for random walks with drift.


title: Spectroscopic evolution of massive stars on the main sequence

abstract:
  We provide an observational view of evolutionary models in the
Hertzsprung--Russell diagram, on the main sequence. For that we computed
evolutionary models with the code STAREVOL for 15 < M/Msun < 100. We
subsequently calculated atmosphere models at specific points along the
evolutionary tracks, using the code CMFGEN. Synthetic spectra obtained in this
way were classified as if they were observational data. We tested our spectral
classification by comparison to observed spectra of various stars. We also
compared our results with empirical data of a large number of OB stars. We
obtain spectroscopic sequences along evolutionary tracks. In our computations,
the earliest O stars (O2-3.5) appear only above ~50 Msun. For later spectral
types, a similar mass limit exists, but is lower. A luminosity class V does not
correspond to the entire main sequence. This only holds for the 15 Msun track.
As mass increases, a larger portion of the main sequence is spent in luminosity
class III. Above 50 Msun, supergiants appear before the end of core-hydrogen
burning. Dwarf stars do not occur on the zero-age main sequence above 80 Msun.
Consequently, the distribution of luminosity class V in the HR diagram cannot
be used to constrain the size of the convective core. The distribution of
dwarfs and giants in the HR diagram agrees well with the location of stars
analyzed by means of quantitative spectroscopy. For supergiants, there is a
slight discrepancy in the sense that luminosity class I is observed slightly
earlier than our predictions. This is mainly due to wind densities that affect
the luminosity class diagnostic lines. We predict an upper mass limit for dwarf
stars (~60 Msun) that is found consistent with the rarity of O2V stars in the
Galaxy. Stars with WNh spectral type are not predicted by our models. Stronger
winds are required to produce the characteristic emission lines of these
objects.


title: The conventions for the polarization angle

abstract:
  Since more than a century astronomers measure the position angle of the major
axis of the polarization ellipse starting from the North direction and
increasing counter-clockwise, when looking at the source. This convention has
been enforced by the IAU with a Resolution in 1973. Much later the WMAP
satellite, which has observed the polarization of the cosmic microwave
background, has unfortunately adopted the opposite convention: the polarization
position angle is measured starting from the South and increasing clockwise,
when looking at the source. This opposite convention has been followed by most
cosmic microwave background polarization experiments and is causing obvious
problems and misunderstandings. The attempts and prospects to enforce the
official IAU convention are described.


title:
Definition of the Riesz Derivative and its Application to Space
  Fractional Quantum Mechanics

abstract:
  We investigate and compare different representations of the Riesz derivative,
which plays an important role in anomalous diffusion and space fractional
quantum mechanics. In particular, we show that a certain representation of the
Riesz derivative that is generally given as also valid for order alpha equals
1, behaves no differently than the other definition given in terms of its
Fourier transform. In the light of this, we discuss the alpha goes to 1 limit
of the space fractional quantum mechanics and its consistency.


title:
The Quantum State Of The Universe From Deformation Quantization and
  Classical-Quantum Correlation

abstract:
  In this paper we study the quantum cosmology of homogeneous and isotropic
cosmology, via the Weyl-Wigner-Groenewold-Moyal formalism of phase space
quantization, with perfect fluid as a matter source. The corresponding quantum
cosmology is described by the Moyal-Wheeler-DeWitt equation which has exact
solutions in Moyal phase space, resulting in Wigner quasiprobability
distribution functions peaking around the classical paths for large values of
scale factor. We show that the Wigner functions of these models are peaked
around the non-singular universes with quantum modified density parameter of
radiation.


title:
Polariton pattern formation and photon statistics of the associated
  emission

abstract:
  We report on the formation of a diverse family of transverse spatial polygon
patterns in a microcavity polariton fluid under coherent driving by a
blue-detuned pump. Patterns emerge spontaneously as a result of
energy-degenerate polariton-polariton scattering from the pump state to
interfering high order vortex and antivortex modes, breaking azimuthal
symmetry. The interplay between a multimode parametric instability and
intrinsic optical bistability leads to a sharp spike in the value of second
order coherence $g^{(2)}(0)$ of the emitted light, which we attribute to the
strongly superlinear kinetics of the underlying scattering processes driving
the formation of patterns. We show numerically by means of a linear stability
analysis how the growth of parametric instabilities in our system can lead to
spontaneous symmetry breaking, predicting the formation and competition of
different pattern states in good agreement with experimental observations.


title: Perfect valley polarization in MoS2

abstract:
  We study perfect valley polarization in a molybdenum disulfide MoS2
nanoribbon monolayer using two bands Hamiltonian model and non-equilibrium
Green's function method. The device consists of a one-dimensional quantum wire
of MoS2 monolayer sandwiched between two zigzag MoS2 nanoribbons such that the
sites A and B of the honeycomb lattice are constructed by the molecular orbital
of Mo atoms, only. Spin-valley coupling is seen in energy dispersion curve due
to the inversion asymmetry and time-reversal symmetry. Although, the time
reversal symmetry is broken by applying an external magnetic field, the valley
polarization is very small. A valley polarization equal to 46% can be achieved
using an exchange field of 0.13 eV. It is shown that a particular spin-valley
combination with perfect valley polarization can be selected based on a given
set of exchange field and gate voltage as input parameters. Therefore, the
valley polarization can be detected by detecting the spin degree of freedom.


title: Rotating Stars in Relativity

abstract:
  Rotating relativistic stars have been studied extensively in recent years,
both theoretically and observationally, because of the information they might
yield about the equation of state of matter at extremely high densities and
because they are considered to be promising sources of gravitational waves. The
latest theoretical understanding of rotating stars in relativity is reviewed in
this updated article. The sections on equilibrium properties and on
nonaxisymmetric oscillations and instabilities in $f$-modes and $r$-modes have
been updated. Several new sections have been added on equilibria in modified
theories of gravity, approximate universal relationships, the one-arm spiral
instability, on analytic solutions for the exterior spacetime, rotating stars
in LMXBs, rotating strange stars, and on rotating stars in numerical relativity
including both hydrodynamic and magnetohydrodynamic studies of these objects.


title: Statics and dynamics of a self-bound matter-wave quantum ball

abstract:
  We study the statics and dynamics of a stable, mobile, three-dimensional
matter-wave spherical quantum ball created in the presence of an attractive
two-body and a very small repulsive three-body interaction. The quantum ball
can propagate with a constant velocity in any direction in free space and its
stability under a small perturbation is established numerically and
variationally. In frontal head-on and angular collisions at large velocities
two quantum balls behave like quantum solitons. Such collision is found to be
quasi elastic and the quantum balls emerge after collision without any change
of direction of motion and velocity and with practically no deformation in
shape. When reflected by a hard impenetrable plane, the quantum ball bounces
off like a wave obeying the law of reflection without any change of shape or
speed. However, in a collision at small velocities two quantum balls coalesce
to form a larger ball which we call a quantum-ball breather. We point out the
similarity and difference between the collision of two quantum and classical
balls. The present study is based on an analytic variational approximation and
a full numerical solution of the mean-field Gross-Pitaevskii equation using the
parameters of $^7$Li atoms.


title: ActionFlowNet: Learning Motion Representation for Action Recognition

abstract:
  Even with the recent advances in convolutional neural networks (CNN) in
various visual recognition tasks, the state-of-the-art action recognition
system still relies on hand crafted motion feature such as optical flow to
achieve the best performance. We propose a multitask learning model
ActionFlowNet to train a single stream network directly from raw pixels to
jointly estimate optical flow while recognizing actions with convolutional
neural networks, capturing both appearance and motion in a single model. We
additionally provide insights to how the quality of the learned optical flow
affects the action recognition. Our model significantly improves action
recognition accuracy by a large margin 31% compared to state-of-the-art
CNN-based action recognition models trained without external large scale data
and additional optical flow input. Without pretraining on large external
labeled datasets, our model, by well exploiting the motion information,
achieves competitive recognition accuracy to the models trained with large
labeled datasets such as ImageNet and Sport-1M.


title:
Online Actions with Offline Impact: How Online Social Networks Influence
  Online and Offline User Behavior

abstract:
  Many of today's most widely used computing applications utilize social
networking features and allow users to connect, follow each other, share
content, and comment on others' posts. However, despite the widespread adoption
of these features, there is little understanding of the consequences that
social networking has on user retention, engagement, and online as well as
offline behavior. Here, we study how social networks influence user behavior in
a physical activity tracking application. We analyze 791 million online and
offline actions of 6 million users over the course of 5 years, and show that
social networking leads to a significant increase in users' online as well as
offline activities. Specifically, we establish a causal effect of how social
networks influence user behavior. We show that the creation of new social
connections increases user online in-application activity by 30%, user
retention by 17%, and user offline real-world physical activity by 7% (about
400 steps per day). By exploiting a natural experiment we distinguish the
effect of social influence of new social connections from the simultaneous
increase in user's motivation to use the app and take more steps. We show that
social influence accounts for 55% of the observed changes in user behavior,
while the remaining 45% can be explained by the user's increased motivation to
use the app. Further, we show that subsequent, individual edge formations in
the social network lead to significant increases in daily steps. These effects
diminish with each additional edge and vary based on edge attributes and user
demographics. Finally, we utilize these insights to develop a model that
accurately predicts which users will be most influenced by the creation of new
social network connections.


title: DERGMs: Degeneracy-restricted exponential random graph models

abstract:
  Exponential random graph models, or ERGMs, are a flexible and general class
of models for modeling dependent data. While the early literature has shown
them to be powerful in capturing many network features of interest, recent work
highlights difficulties related to the models' ill behavior, such as most of
the probability mass being concentrated on a very small subset of the parameter
space. This behavior limits both the applicability of an ERGM as a model for
real data and inference and parameter estimation via the usual Markov chain
Monte Carlo algorithms.
  To address this problem, we propose a new exponential family of models for
random graphs that build on the standard ERGM framework. Specifically, we solve
the problem of computational intractability and `degenerate' model behavior by
an interpretable support restriction. We introduce a new parameter based on the
graph-theoretic notion of degeneracy, a measure of sparsity whose value is
commonly low in real-worlds networks. The new model family is supported on the
sample space of graphs with bounded degeneracy and is called
degeneracy-restricted ERGMs, or DERGMs for short. Since DERGMs generalize ERGMs
-- the latter is obtained from the former by setting the degeneracy parameter
to be maximal -- they inherit good theoretical properties, while at the same
time place their mass more uniformly over realistic graphs.
  The support restriction allows the use of new (and fast) Monte Carlo methods
for inference, thus making the models scalable and computationally tractable.
We study various theoretical properties of DERGMs and illustrate how the
support restriction improves the model behavior. We also present a fast Monte
Carlo algorithm for parameter estimation that avoids many issues faced by
Markov Chain Monte Carlo algorithms used for inference in ERGMs.


title:
Measuring Adverse Drug Effects on Multimorbity using Tractable Bayesian
  Networks

abstract:
  Managing patients with multimorbidity often results in polypharmacy: the
prescription of multiple drugs. However, the long-term effects of specific
combinations of drugs and diseases are typically unknown. In particular, drugs
prescribed for one condition may result in adverse effects for the other. To
investigate which types of drugs may affect the further progression of
multimorbidity, we query models of diseases and prescriptions that are learned
from primary care data. State-of-the-art tractable Bayesian network
representations, on which such complex queries can be computed efficiently, are
employed for these large medical networks. Our results confirm that
prescriptions may lead to unintended negative consequences in further
development of multimorbidity in cardiovascular diseases. Moreover, a drug
treatment for one disease group may affect diseases of another group.


title:
Quantum Walk in Periodic Potential on a Line and a Model of Interacting
  Opinions

abstract:
  Two subjects are discussed in this work: localisation and recurrence in a
model of quantum walk in a periodic potential, and a model of opinion dynamics
with multiple choices of opinions.


title: Relativistic analysis of stochastic kinematics

abstract:
  The relativistic analysis of stochastic kinematics is developed in order to
determine the transformation of the effective diffusivity tensor in inertial
frames. Poisson-Kac stochastic processes are initially considered. For
one-dimensional spatial models, the effective diffusion coefficient $D$
measured in a frame $\Sigma$ moving with velocity $w$ with respect to the rest
frame of the stochastic process can be expressed as $D= D_0 \, \gamma^{-3}(w)$.
Subsequently, higher dimensional processes are analyzed, and it is shown that
the diffusivity tensor in a moving frame becomes non-isotropic with
$D_\parallel = D_0 \, \gamma^{-3}(w)$, and $D_\perp = D_0 \, \gamma^{-1}(w)$,
where $D_\parallel$ and $D_\perp$ are the diffusivities parallel and orthogonal
to the velocity of the moving frame. The analysis of discrete Space-Time
Diffusion processes permits to obtain a general transformation theory of the
tensor diffusivity, confirmed by several different simulation experiments.
Several implications of the theory are also addressed and discussed.


title:
Suzaku observations of the merging galaxy cluster Abell2255: The
  northeast radio relic

abstract:
  We present the results of deep 140 ks Suzaku X-ray observations of the
north-east (NE) radio relic of the merging galaxy cluster Abell2255. The
temperature structure of Abell2255 is measured out to 0.9 times the virial
radius (1.9 Mpc) in the NE direction for the first time. The Suzaku temperature
map of the central region suggests a complex temperature distribution, which
agrees with previous work. Additionally, on a larger-scale, we confirm that the
temperature drops from 6 keV around the cluster center to 3 keV at the
outskirts, with two discontinuities at {\it r}$\sim$5\arcmin~(450 kpc) and
$\sim$12\arcmin~(1100 kpc) from the cluster center. Their locations coincide
with surface brightness discontinuities marginally detected in the XMM-Newton
image, which indicates the presence of shock structures. From the temperature
drop, we estimate the Mach numbers to be ${\cal M}_{\rm inner}\sim$1.2 and,
${\cal M}_{\rm outer}\sim$1.4. The first structure is most likely related to
the large cluster core region ($\sim$350--430 kpc), and its Mach number is
consistent with the XMM-Newton observation (${\cal M}\sim$1.24: Sakelliou &
Ponman 2006). Our detection of the second temperature jump, based on the Suzaku
key project observation, shows the presence of a shock structure across the NE
radio relic. This indicates a connection between the shock structure and the
relativistic electrons that generate radio emission. Across the NE radio relic,
however, we find a significantly lower temperature ratio
($T_1/T_2\sim1.44\pm0.16$ corresponds to~${\cal M}_{\rm X-ray}\sim1.4$) than
the value expected from radio wavelengths, based on the standard diffusive
shock acceleration mechanism ($T_1/T_2>$ 3.2 or ${\cal M}_{\rm Radio}>$ 2.8).


title: A note on the Chermak-Delgado lattice of a finite group

abstract:
  In this note we describe the structure of finite groups G whose
Chermak-Delgado lattice is the interval [G/Z(G)] = {H \in L(G) \mid Z(G)\leq
H\leq G}.


title:
The Fermi surface of Sr2RuO4: spin-orbit and anisotropic Coulomb
  interaction effects

abstract:
  The topology of the Fermi surface of Sr2RuO4 is well described by
local-density approximation calculations with spin-orbit interaction, but the
relative size of its different sheets is not. By accounting for many-body
effects via dynamical mean-field theory, we show that the standard isotropic
Coulomb interaction alone worsens or does not correct this discrepancy. In
order to reproduce experiments, it is essential to account for the Coulomb
anisotropy. The latter is small but has strong effects; it competes with the
Coulomb-enhanced spin-orbit coupling and the isotropic Coulomb term in
determining the Fermi surface shape. Its effects are likely sizable in other
correlated multi-orbital systems. In addition, we find that the low-energy
self-energy matrix -- responsible for the reshaping of the Fermi surface --
sizably differ from the static Hartree-Fock limit. Finally, we find a strong
spin-orbital {entanglement}; this supports the view that the conventional
description of Cooper pairs via factorized spin and orbital part might not
apply to Sr2RuO4.


title: A Plancherel measure associated to set partitions and its limit

abstract:
  In recent years increasing attention has been paid on the area of
supercharacter theories, especially to those of the upper unitriangular group.
A particular supercharacter theory, in which supercharacters are indexed by set
partitions, has several interesting properties, which make it object of further
study. We define a natural generalization of the Plancherel measure, called
superplancherel measure, and prove a limit shape result for a random set
partition according to this distribution. We also give a description of the
asymptotical behavior of two set partition statistics related to the
supercharacters. The study of these statistics when the set partitions are
uniformly distributed has been done by Chern, Diaconis, Kane and Rhoades.


title:
A Look Back at the Ehrenfest Classification. Translation and Commentary
  of Ehrenfest's 1933 paper introducing the notion of phase transitions of
  different order

abstract:
  A translation of Paul Ehrenfest's 1933 paper, entitled "Phase transitions in
the usual and generalized sense, classified according to the singularities of
the thermodynamic potential" is presented. Some historical commentary about the
paper's context is also given.


title:
Reducing phonon-induced decoherence in solid-state single-photon sources
  with cavity quantum electrodynamics

abstract:
  Solid-state emitters are excellent candidates for developing integrated
sources of single photons. Yet, phonons degrade the photon indistinguishability
both through pure dephasing of the zero-phonon line and through phonon-assisted
emission. Here, we study theoretically and experimentally the
indistinguishability of photons emitted by a semiconductor quantum dot in a
microcavity as a function of temperature. We show that a large coupling to a
high quality factor cavity can simultaneously reduce the effect of both
phonon-induced sources of decoherence. It first limits the effect of pure
dephasing on the zero phonon line with indistinguishabilities above $97\%$ up
to $18$ K. Moreover, it efficiently redirects the phonon sidebands into the
zero-phonon line and brings the indistinguishability of the full emission
spectrum from $87\%$ (resp. $24\%$) without cavity effect to more than $99\%$
(resp. $76\%$) at $0$ K (resp. $20$ K). We provide guidelines for optimal
cavity designs that further minimize the phonon-induced decoherence.


title:
The evolution of the Oxygen abundance radial gradient in the Milky Way
  Galaxy disk

abstract:
  We review the state of our chemical evolution models for spiral and low mass
galaxies. We analyze the consequences of using different stellar yields, infall
rate laws and star formation prescriptions in the time/redshift evolution of
the radial distributions of abundances, and other quantities as star formation
rate or gas densities, in the Milky Way Galaxy; In particular we will study the
evolution of the Oxygen abundance radial gradient analyzing its relation with
the ratio SFR/infall. We also compare the results with our old chemical
evolution models, cosmological simulations and with the existing data, mainly
with the planetary nebulae abundances.


title: Deformed relativity symmetries and the local structure of spacetime

abstract:
  A spacetime interpretation of deformed relativity symmetry groups was
recently proposed by resorting to Finslerian geometries, seen as the outcome of
a continuous limit endowed with first order corrections from the quantum
gravity regime. In this work we further investigate such connection between
deformed algebras and Finslerian geometries by showing that the Finsler
geometries associated to the generalisation of the Poincar\'{e} group (the so
called $\kappa$-Poincar\'{e} Hopf algebra) are maximally symmetric spacetimes
which are also of the Berwald type: Finslerian spacetimes for which the
connections are substantially Riemannian, belonging to the unique class for
which the weak equivalence principle still holds. We also extend this analysis
by considering a generalization of the de Sitter group (the so called $q$-de
Sitter group) and showing that its associated Finslerian geometry reproduces
locally the one from the $\kappa$-Poincar\'{e} group and that itself can be
recast in a Berwald form in an appropriate limit.


title: Parameter uncertainty and reserve risk under Solvency II

abstract:
  In this article we consider the parameter risk in the context of internal
modelling of the reserve risk under Solvency II.
  We discuss two opposed perspectives on parameter uncertainty and point out
that standard methods of classical reserving focusing on the estimation error
of claims reserves are in general not appropriate to model the impact of
parameter uncertainty upon the actual risk of economic losses from the
undertakings's perspective.
  Referring to the requirements of Solvency II we assess methods to model
parameter uncertainty for the reserve risk by comparing the probability of
solvency actually attained when modelling the solvency risk capital requirement
based on the respective method to the required confidence level. Using the
simple example of a normal model we show that the bootstrapping approach is not
appropriate to model parameter uncertainty according to this criterion. We then
present an adaptation of the approach proposed in \cite {froehlich2014}.
Experimental results demonstrate that this new method yields a risk capital
model for the reserve risk achieving the required confidence level in good
approximation.


title: FIMP and Muon ($g-2$) in a U$(1)_{L_{\mu}-L_{\tau}}$ Model

abstract:
  The tightening of the constraints on the standard thermal WIMP scenario has
forced physicists to propose alternative dark matter (DM) models. One of the
most popular alternate explanations of the origin of DM is the non-thermal
production of DM via freeze-in. In this scenario the DM never attains thermal
equilibrium with the thermal soup because of its feeble coupling strength
($\sim 10^{-12}$) with the other particles in the thermal bath and is generally
called the Feebly Interacting Massive Particle (FIMP). In this work, we present
a gauged U(1)$_{L_{\mu}-L_{\tau}}$ extension of the Standard Model (SM) which
has a scalar FIMP DM candidate and can consistently explain the DM relic
density bound. In addition, the spontaneous breaking of the
U(1)$_{L_{\mu}-L_{\tau}}$ gauge symmetry gives an extra massive neutral gauge
boson $Z_{\mu\tau}$ which can explain the muon ($g-2$) data through its
additional one-loop contribution to the process. Lastly, presence of three
right-handed neutrinos enable the model to successfully explain the small
neutrino masses via the Type-I seesaw mechanism. The presence of the
spontaneously broken U(1)$_{L_{\mu}-L_{\tau}}$ gives a particular structure to
the light neutrino mass matrix which can explain the peculiar mixing pattern of
the light neutrinos.


title: Generalized Algorithm for Wythoff's Game with Basis Vector $(2^b,2^b)$

abstract:
  Wythoff's Game is a variation of Nim in which players may take an equal
number of stones from each pile or make valid Nim moves. W. A. Wythoff proved
that the set of P-Positions (losing position), $C$, for Wythoff's Game is given
by $C := \left\{ (\lfloor k\phi \rfloor, \lfloor k\phi^2 \rfloor), (\lfloor
k\phi^2 \rfloor, \lfloor k\phi \rfloor) : k \in \mathbb Z_{\geq 0} \right\}$.
An open Wythoff problem remains where players make the valid Nim moves or
remove $kb$ stones from each pile, where $b$ is a fixed integer. We denote this
as the $(b,b)$ game. For example, regular Wythoff's Game is just the $(1,1)$
game. In 2009, Duch${\^e}$ne and Gravier proved an algorithm to generate the
set of P-Positions for the $(2,2)$ game by exploiting the periodic nature of
the differences of stones between the two piles modulo $4$. We observe similar
cyclic behaviour for any $b$, where $b$ is a power of $2$, modulo $b^2$, and
construct an algorithm to generate the set of P-Positions for this game. Let
$a$ be a power of $2$. We prove our algorithm works by first showing that it
holds for the first $a^2$ terms in the $(a,a)$ game. Next, we construct an
ordered multiset for the $(2a,2a)$ game from the $a^2$ terms, and an inductive
proof follows. Moreover, we conjecture that all cyclic games require $a$ to be
a power of $2$, suggesting that there is no similar structure in the
generalised $(b,b)$ game where $b$ isn't a power of $2$. Future directions for
generalising this result would likely utilise numeration systems, particularly
the PV numbers.


title:
Gauge hierarchy problem in asymptotically safe gravity--the resurgence
  mechanism

abstract:
  The gauge hierarchy problem could find a solution within the scenario of
asymptotic safety for quantum gravity. We discuss a "resurgence mechanism"
where the running dimensionless coupling responsible for the Higgs scalar mass
first decreases in the ultraviolet regime and subsequently increases in the
infrared regime. A gravity induced large anomalous dimension plays a crucial
role for the required "self-tuned criticality" in the ultraviolet regime beyond
the Planck scale.


title:
Wave propagation through disordered media without backscattering and
  intensity variations

abstract:
  A fundamental manifestation of wave scattering in a disordered medium is the
highly complex intensity pattern the waves acquire due to multi-path
interference. Here we show that these intensity variations can be entirely
suppressed by adding disorder-specific gain and loss components to the medium.
The resulting constant-intensity (CI) waves in such non-Hermitian scattering
landscapes are free of any backscattering and feature perfect transmission
through the disorder. An experimental demonstration of these unique wave states
is envisioned based on spatially modulated pump beams that can flexibly control
the gain and loss components in an active medium.


title: Blind Identification of SM and Alamouti STBC-OFDM Signals

abstract:
  This paper proposes an efficient identification algorithm for spatial
multiplexing (SM) and Alamouti (AL) coded orthogonal frequency division
multiplexing (OFDM) signals. The cross-correlation between the received signals
from different antennas is exploited to provide a discriminating feature to
identify SM-OFDM and AL-OFDM signals. The proposed algorithm requires neither
estimation of the channel coefficients and noise power, nor the modulation of
the transmitted signal. Moreover, it does not need space-time block code (STBC)
or OFDM block synchronization. The effectiveness of the proposed algorithm is
demonstrated through extensive simulation experiments in the presence of
diverse transmission impairments, such as time and frequency offsets, Doppler
frequency, and spatially correlated fading.


title: Young stars in the periphery of the Large Magellanic Cloud

abstract:
  Despite their close proximity, the complex interplay between the two
Magellanic Clouds, the Milky Way, and the resulting tidal features, is still
poorly understood. Recent studies have shown that the Large Magellanic Cloud
(LMC) has a very extended disk strikingly perturbed in its outskirts. We search
for recent star formation in the far outskirts of the LMC, out to ~30 degrees
from its center. We have collected intermediate-resolution spectra of
thirty-one young star candidates in the periphery of the LMC and measured their
radial velocity, stellar parameters, distance and age. Our measurements confirm
membership to the LMC of six targets, for which the radial velocity and
distance values match well those of the Cloud. These objects are all young
(10-50 Myr), main-sequence stars projected between 7 and 13 degrees from the
center of the parent galaxy. We compare the velocities of our stars with those
of a disk model, and find that our stars have low to moderate velocity
differences with the disk model predictions, indicating that they were formed
in situ. Our study demonstrates that recent star formation occurred in the far
periphery of the LMC, where thus far only old objects were known. The spatial
configuration of these newly-formed stars appears ring-like with a radius of 12
kpc, and a displacement of 2.6 kpc from the LMC's center. This structure, if
real, would be suggestive of a star-formation episode triggered by an
off-center collision between the Small Magellanic Cloud and the LMC's disk.


title: Bayesian forecasting of electoral outcomes with new parties' competition

abstract:
  This paper proposed a methodology to forecast electoral outcomes using the
result of the combination of a fundamental model and a model-based aggregation
of polls. We propose a Bayesian hierarchical structure for the fundamental
model that synthesises data at the provincial, regional and national level. We
use a Bayesian strategy to combine the fundamental model with the information
coming for recent polls. This model can naturally be updated every time new
information, for instance a new poll, becomes available. This methodology is
well suited to deal with increasingly frequent situations in which new
political parties enter an electoral competition, although our approach is
general enough to accommodate any other electoral situation. We illustrate the
advantages of our method using the 2015 Spanish Congressional Election in which
two new parties ended up receiving 30\% of the votes. We compare the predictive
performance of our model versus alternative models. In general the predictions
of our model outperform the alternative specifications, including hybrid models
that combine fundamental and polls models. Our predictions are, in relative
terms, particularly accurate in predicting the seats obtained by each political
party.


title: Quivers and equations a la Pl\"ucker for the Hilbert scheme

abstract:
  Several moduli spaces parametrizing linear subspaces of the projective space
are cut out by linear and quadratic equations in their natural embedding:
Grassmannians, Flag varieties, and Schubert varieties. The goal of this paper
is to prove that a similar statement holds when one replaces linear subspaces
with algebraic subschemes of the projective space. We exhibit equations of
degree 1 and 2 that define schematically the Hilbert schemes
$\mathbf{Hilb}^{p}_{\mathbb P^n}$ for all (possibly nonconstant) Hilbert
polynomials $p$. The equations are reminiscent of the Pl\"ucker relations on
the Grassmannians: they are built formally with permutations on indexes on the
Pl\"ucker coordinates. Our method relies on a new construction of the Hilbert
scheme as a quotient of a scheme of quiver representations.


title: Polarized $^3$He target and final state interactions in SiDIS

abstract:
  Jefferson Lab (JLab) is starting a wide experimental program aimed at
studying the neutron's structure, with a great emphasis on the extraction of
the parton transverse-momentum distributions (TMDs). To this end,
Semi-inclusive deep-inelastic scattering (SiDIS) experiments on polarized
$^3$He will be carried out, providing, together with proton and deuteron data,
a sound flavor decomposition of the TMDs. Given the expected high statistical
accuracy, it is crucial to disentangle nuclear and partonic degrees of freedom
to get an accurate theoretical description of both initial and final states. In
this contribution, a preliminary study of the Final State Interaction (FSI) in
the standard SiDIS, where a pion (or a Kaon) is detected in the final state is
presented, in view of constructing a realistic description of the nuclear
initial and final states.


title: Different models of gravitating Dirac fermions in optical lattices

abstract:
  In this paper I construct the naive lattice Dirac Hamiltonian describing the
propagation of fermions in a generic 2D optical metric for different lattice
and flux-lattice geometries. First, I apply a top-down constructive approach
that we first proposed in [Boada {\it et al.,New J. Phys.} {\bf 13} 035002
(2011)] to the honeycomb and to the brickwall lattices. I carefully discuss how
gauge transformations that generalize momentum (and Dirac cone) shifts in the
Brillouin zone in the Minkowski homogeneous case can be used in order to change
the phases of the hopping. In particular, I show that lattice Dirac Hamiltonian
for Rindler spacetime in the honeycomb and brickwall lattices can be realized
by considering real and isotropic (but properly position dependent) tunneling
terms. For completeness, I also discuss a suitable formulation of Rindler Dirac
Hamiltonian in semi-synthetic brickwall and $\pi$-flux square lattices (where
one of the dimension is implemented by using internal spin states of atoms as
we originally proposed in [Boada {\it et al.,Phys. Rev. Lett. } {\bf 108}
133001 (2012)] and [Celi {\it et al.,Phys. Rev. Lett. } {\bf 112} 043001
(2012)]).


title:
Nucleon tomography. What can we do better today than Rutherford 100
  years ago?

abstract:
  A survey is presented on the current status of 3D nucleon tomography. Several
research frontiers are addressed that dominate modern physics from theory to
current and future experiments. We have now a much more detailed spatial image
of the nucleon thanks to various theoretical concepts and methods to describe
its charge distribution and spin decomposition which are highlighted here. The
progress of lattice computations of these quantities is reported and the
prospects of what we can come to expect in the near future are discussed.
Multi-dimensional maps of the nucleon's partonic structure appear now within
reach of forthcoming experiments.


title:
A Mecke-type formula and Markov properties for STIT tessellation
  processes

abstract:
  An analogue of the classical Mecke formula for Poisson point processes is
proved for the class of space-time STIT tessellation processes. From this key
identity the Markov property of a class of associated random processes is
derived. This in turn is used to determine the distribution of the number of
internal vertices of the typical maximal tessellation segment.


title: Clipper: A Low-Latency Online Prediction Serving System

abstract:
  Machine learning is being deployed in a growing number of applications which
demand real-time, accurate, and robust predictions under heavy query load.
However, most machine learning frameworks and systems only address model
training and not deployment.
  In this paper, we introduce Clipper, a general-purpose low-latency prediction
serving system. Interposing between end-user applications and a wide range of
machine learning frameworks, Clipper introduces a modular architecture to
simplify model deployment across frameworks and applications. Furthermore, by
introducing caching, batching, and adaptive model selection techniques, Clipper
reduces prediction latency and improves prediction throughput, accuracy, and
robustness without modifying the underlying machine learning frameworks. We
evaluate Clipper on four common machine learning benchmark datasets and
demonstrate its ability to meet the latency, accuracy, and throughput demands
of online serving applications. Finally, we compare Clipper to the TensorFlow
Serving system and demonstrate that we are able to achieve comparable
throughput and latency while enabling model composition and online learning to
improve accuracy and render more robust predictions.


title:
Characterizing the maximum parameter of the total-variation denoising
  through the pseudo-inverse of the divergence

abstract:
  We focus on the maximum regularization parameter for anisotropic
total-variation denoising. It corresponds to the minimum value of the
regularization parameter above which the solution remains constant. While this
value is well know for the Lasso, such a critical value has not been
investigated in details for the total-variation. Though, it is of importance
when tuning the regularization parameter as it allows fixing an upper-bound on
the grid for which the optimal parameter is sought. We establish a closed form
expression for the one-dimensional case, as well as an upper-bound for the
two-dimensional case, that appears reasonably tight in practice. This problem
is directly linked to the computation of the pseudo-inverse of the divergence,
which can be quickly obtained by performing convolutions in the Fourier domain.


title: Nonlinear oscillations and waves in multi-species cold plasmas

abstract:
  The spatio-temporal evolution of nonlinear oscillations in multi-species
plasma is revisited to provide more insight into the physics of phase mixing by
constructing two sets of nonlinear solutions up to the second order. The first
solution exhibits perfect oscillations in the linear regime and phase mixing
appears only nonlinearly in the second order as a response to the ponderomotive
forces. This response can be both direct and indirect. The indirect
contribution of the ponderomotive forces appears through self-consistently
generated low frequency fields. Furthermore, the direct and indirect
contributions of the ponderomotive forces on the phase mixing process is
explored and it is found that the indirect contribution is negligible in an
electron-ion plasma and it disappears in the case of electron-positron plasma,
yet represents an equal contribution in the electron-positron-ion plasma.
However, the second solution does not exhibit any phase mixing due to the
absence of ponderomotive forces but results in an undistorted nonlinear
traveling wave. These investigations have relevance for
laboratory/astrophysical multi-species plasma.


title: Minimum energy control for complex networks

abstract:
  The aim of this paper is to shed light on the problem of controlling a
complex network with minimal control energy. We show first that the control
energy depends on the time constant of the modes of the network, and that the
closer the eigenvalues are to the imaginary axis of the complex plane, the less
energy is required for complete controllability. In the limit case of networks
having all purely imaginary eigenvalues (e.g. networks of coupled harmonic
oscillators), several constructive algorithms for minimum control energy driver
node selection are developed. A general heuristic principle valid for any
directed network is also proposed: the overall cost of controlling a network is
reduced when the controls are concentrated on the nodes with highest ratio of
weighted outdegree vs indegree.


title: Internally connected graphs and the Kashiwara-Vergne Lie algebra

abstract:
  It is conjectured that the Kashiwara-Vergne Lie algebra
$\widehat{\mathfrak{krv}}_2$ is isomorphic to the direct sum of the
Grothendieck-Teichm\"uller Lie algebra $\mathfrak{grt}_1$ and a one-dimensional
Lie algebra. In this paper, we use the graph complex of internally connected
graphs to define a nested sequence of Lie subalgebras of
$\widehat{\mathfrak{krv}}_2$ whose intersection is $\mathfrak{grt}_1$, thus
giving a way to interpolate between these two Lie algebras.


title: Is a typical bi-Perron number a pseudo-Anosov dilatation?

abstract:
  In this note, we deduce a partial answer to the question in the title. In
particular, we show that asymptotically almost all bi-Perron algebraic unit
whose characteristic polynomial has degree at most $2n$ do not correspond to
dilatations of pseudo-Anosov maps on a closed orientable surface of genus $n$
for $n\geq 10$. As an application of the argument, we also obtain a statement
on the number of closed geodesics of the same length in the moduli space of
area one abelian differentials for low genus cases.


title: An Epidemiological Mechanistic Model of Box Office Dynamics

abstract:
  In this paper we propose a mechanistic model that links micro social
interactions to macro observables in the case of diffusion of film-going
decisions. We devise a generalized epidemic model to capture the temporal
evolution of box office revenues. The model adds social influence and memory
effects to conventional epidemic models. Fitting the model to a temporal data
set containing domestic weekly revenue of the 5000 top US-grossing films of all
time, we find that a two-parameter model can capture a remarkable portion of
the observed variance in the data. Using the distribution of the estimated
parameters for different genres, we then present a predictive model which
provides reasonable a-priori estimates of future sale as a function of time.


title: Robust Multiplication-based Tests for Reed-Muller Codes

abstract:
  We consider the following multiplication-based tests to check if a given
function $f: \mathbb{F}_q^n\to \mathbb{F}_q$ is a codeword of the Reed-Muller
code of dimension $n$ and order $d$ over the finite field $\mathbb{F}_q$ for
prime $q$ (i.e., $f$ is the evaluation of a degree-$d$ polynomial over
$\mathbb{F}_q$ for $q$ prime).
  * $\mathrm{Test}_{e,k}$: Pick $P_1,\ldots,P_k$ independent random degree-$e$
polynomials and accept iff the function $fP_1\cdots P_k$ is the evaluation of a
degree-$(d+ek)$ polynomial (i.e., is a codeword of the Reed-Muller code of
dimension $n$ and order $(d+ek)$).
  We prove the robust soundness of the above tests for large values of $e$,
answering a question of Dinur and Guruswami [Israel Journal of Mathematics,
209:611-649, 2015]. Previous soundness analyses of these tests were known only
for the case when either $e=1$ or $k=1$. Even for the case $k=1$ and $e>1$,
earlier soundness analyses were not robust.
  We also analyze a derandomized version of this test, where (for example) the
polynomials $P_1,\dots,P_k$ can be the same random polynomial $P$. This
generalizes a result of Guruswami et al. [SIAM J. Comput., 46(1):132-159,
2017].
  One of the key ingredients that go into the proof of this robust soundness is
an extension of the standard Schwartz-Zippel lemma over general finite fields
$\mathbb{F}_q$, which may be of independent interest.