title:
The 2011 unrest at Katla volcano: characterization and interpretation of
  the tremor sources

abstract:
  A 23 hour tremor burst was recorded on July 8-9th 2011 at the Katla
subglacial volcano, one of the most active and hazardous volcanoes in Iceland.
This was associated with deepening of cauldrons on the ice cap and a glacial
flood that caused damage to infrastructure. Increased earthquake activity
within the caldera started a few days before and lasted for months afterwards
and new seismic activity started on the south flank. No visible eruption broke
the ice and the question arose as to whether this episode relates to a minor
subglacial eruption with the tremor being generated by volcanic processes, or
by the flood. The tremor signal consisted of bursts with varying amplitude and
duration. We have identified and described three different tremor phases, based
on amplitude and frequency features. A tremor phase associated with the flood
was recorded only at stations closest to the river that flooded, correlating in
time with rising water level observed at gauging stations. Using
back-projection of double cross-correlations, two other phases have been
located near the active ice cauldrons and are interpreted to be caused by
volcanic or hydrothermal processes. The greatly increased seismicity and
evidence of rapid melting of the glacier may be explained by a minor
sub-glacial eruption. It is also plausible that the tremor was generated by
hydrothermal boiling and/or explosions with no magma involved. This may have
been induced by pressure drop triggered by the release of water when the
glacial flood started. All interpretations require an increase of heat released
by the volcano.


title:
Interplay between adsorption and hydrodynamics in nanochannels: towards
  tunable membranes

abstract:
  We study how adsorption of a near-critical binary mixture in a nanopore is
modified by flow inside the pore. We identify three types of steady states upon
variation of the pore P\'{e}clet number (${\rm Pe}_p$), which can be reversibly
accessed by the application of an external pressure. Interestingly, for small
${\rm Pe}_p$ the pore acts as a weakly selective membrane which separates the
mixture. For intermediate ${\rm Pe}_p$, the flow effectively shifts the
adsorption in the pore thereby opening possibilities for enhanced and tunable
solute transport through the pore. For large ${\rm Pe}_p$, the adsorption is
progressively reduced inside the pore, accompanied by a long ranged dispersion
of the mixture far from the pore.


title:
Calculated high-pressure structural properties, lattice dynamics and
  quasi particle band structures of perovskite fluorides KZnF 3 , CsCaF 3 and
  BaLiF 3

abstract:
  A detailed study of the high-pressure structural properties, lattice dynamics
and band structures of perovskite structured fluorides KZnF3, CsCaF3 and BaLiF3
has been carried out by means of density functional theory. The calculated
structural properties including elastic constants and equation of state agree
well with available experimental information. The phonon dispersion curves are
in good agreement with available experimental inelastic neutron scattering
data. The electronic structures of these fluorides have been calculated using
the quasi particle self-consistent [Formula: see text] approximation. The
[Formula: see text] calculations reveal that all the fluorides studied are wide
band gap insulators, and the band gaps are significantly larger than those
obtained by the standard local density approximation, thus emphasizing the
importance of quasi particle corrections in perovskite fluorides.


title:
Temperature-dependent photoluminescence characteristics of GeSn
  epitaxial layers

abstract:
  GeSn epitaxial heterostructures are emerging as prominent candidates for the
monolithic integration of light sources on Si substrates. Here we propose a
judicious explanation for their temperature-dependent photoluminescence (PL)
that is based upon the so far disregarded optical activity of dislocations. By
working at the onset of plastic relaxation, which occurs whenever the epilayer
releases the strain accumulated during growth on the lattice mismatched
substrate, we demonstrate that dislocation nucleation can be explicitly seen in
the PL data. Notably, our findings point out that a monotonous thermal PL
quenching can be observed in coherent films, in spite of the indirect nature of
the GeSn bandgap. Our investigation, therefore, contributes to a deeper
understanding of the recombination dynamics in this intriguing group IV alloy
and offers insights into crucial phenomena shaping the light emission
efficiency.


title: On Profiling Bots in Social Media

abstract:
  The popularity of social media platforms such as Twitter has led to the
proliferation of automated bots, creating both opportunities and challenges in
information dissemination, user engagements, and quality of services. Past
works on profiling bots had been focused largely on malicious bots, with the
assumption that these bots should be removed. In this work, however, we find
many bots that are benign, and propose a new, broader categorization of bots
based on their behaviors. This includes broadcast, consumption, and spam bots.
To facilitate comprehensive analyses of bots and how they compare to human
accounts, we develop a systematic profiling framework that includes a rich set
of features and classifier bank. We conduct extensive experiments to evaluate
the performances of different classifiers under varying time windows, identify
the key features of bots, and infer about bots in a larger Twitter population.
Our analysis encompasses more than 159K bot and human (non-bot) accounts in
Twitter. The results provide interesting insights on the behavioral traits of
both benign and malicious bots.


title:
On unrooted and root-uncertain variants of several well-known
  phylogenetic network problems

abstract:
  The hybridization number problem requires us to embed a set of binary rooted
phylogenetic trees into a binary rooted phylogenetic network such that the
number of nodes with indegree two is minimized. However, from a biological
point of view accurately inferring the root location in a phylogenetic tree is
notoriously difficult and poor root placement can artificially inflate the
hybridization number. To this end we study a number of relaxed variants of this
problem. We start by showing that the fundamental problem of determining
whether an \emph{unrooted} phylogenetic network displays (i.e. embeds) an
\emph{unrooted} phylogenetic tree, is NP-hard. On the positive side we show
that this problem is FPT in reticulation number. In the rooted case the
corresponding FPT result is trivial, but here we require more subtle
argumentation. Next we show that the hybridization number problem for unrooted
networks (when given two unrooted trees) is equivalent to the problem of
computing the Tree Bisection and Reconnect (TBR) distance of the two unrooted
trees. In the third part of the paper we consider the "root uncertain" variant
of hybridization number. Here we are free to choose the root location in each
of a set of unrooted input trees such that the hybridization number of the
resulting rooted trees is minimized. On the negative side we show that this
problem is APX-hard. On the positive side, we show that the problem is FPT in
the hybridization number, via kernelization, for any number of input trees.


title: The quenching of the star formation activity in cluster galaxies

abstract:
  We study the star formation quenching mechanism in cluster galaxies by
fitting the SED of the Herschel Reference Survey, a complete volume-limited
K-band-selected sample of nearby galaxies including objects in different
density regions, from the core of the Virgo cluster to the general field. The
SED are fitted using the CIGALE SED modelling code. The truncated activity of
cluster galaxies is parametrised using a specific SFH with 2 free parameters,
the quenching age QA and the quenching factor QF. These 2 parameters are
crucial for the identification of the quenching mechanism which acts on long
timescales if starvation while rapid and efficient if ram pressure. To be
sensitive to an abrupt and recent variation of the star formation activity, we
combine in a new way 20 UV to FIR photometric bands with 3 age-sensitive Balmer
line absorption indices extracted from available medium-resolution integrated
spectroscopy and with Halpha narrow band imaging data. The use of a truncated
SFH significantly increases the quality of the fit in those objects whose
atomic gas content has been removed during the interaction with the hostile
cluster environment. The typical QA of the perturbed late-type galaxies is QA <
300 Myr whenever the activity of star formation is reduced by 50% < QF <= 80%
and QA < 500 Myr for QF > 80%, while that of the quiescent early-types is QA ~
1-3 Gyr. The fraction of late-types with a star formation activity reduced by
QF > 80% and with an HI-deficiency parameter HI-def > 0.4 drops by a factor of
~ 5 from the inner half virial radius of the Virgo cluster, where the hot
diffuse X-ray emitting gas of the cluster is located, to the outer regions. The
efficient quenching of the star formation activity observed in Virgo suggests
that the dominant stripping process is ram pressure. We discuss the implication
of this result in the cosmological context of galaxy evolution.


title: A regularized tri-linear approach for optical interferometric imaging

abstract:
  In the context of optical interferometry, only undersampled power spectrum
and bispectrum data are accessible. It poses an ill-posed inverse problem for
image recovery. Recently, a tri-linear model was proposed for monochromatic
imaging, leading to an alternated minimization problem. In that work, only a
positivity constraint was considered, and the problem was solved by an
approximated Gauss-Seidel method. In this paper, we propose to improve the
approach on three fundamental aspects. Firstly, we define the estimated image
as a solution of a regularized minimization problem, promoting sparsity in a
fixed dictionary using either an $\ell_1$ or a weighted-$\ell_1$ regularization
term. Secondly, we solve the resultant non-convex minimization problem using a
block-coordinate forward-backward algorithm. This algorithm is able to deal
both with smooth and non-smooth functions, and benefits from convergence
guarantees even in a non-convex context. Finally, we generalize our model and
algorithm to the hyperspectral case, promoting a joint sparsity prior through
an $\ell_{2,1}$ regularization term. We present simulation results, both for
monochromatic and hyperspectral cases, to validate the proposed approach.


title:
Climate network suggests enhanced El Ni\~no global impacts in localized
  areas

abstract:
  We construct directed and weighted climate networks based on near surface air
temperature to investigate the global impacts of El Nino and La Nina. We find
that regions which are characterized by higher positive or negative network in
weighted links, are exhibiting stronger correlations with the El Nino basin and
are warmer or cooler during El Nino or La Nina periods. These stronger
in-weighted activities are found to be concentrated in localized areas, as
compared to non-El Nino periods, whereas a large fraction of the globe is not
influenced by the events. The regions of localized activity vary from one El
Nino (La Nina) event to another; still some El Nino (La Nina) events are more
similar to each other. We quantify this similarity using network community
structure. The results and methodology reported here may be used to improve the
understanding and prediction of El Nino or La Nina events and also may be
applied in the investigation of other climate variables.


title:
Including heavy spin effects in a lattice QCD study of
  static-static-light-light tetraquarks

abstract:
  In previous works we predicted the existence of a $\bar b \bar b u d$
tetraquark with quantum numbers $I(J^P) = 0(1^+)$ using the static
approximation for the $\bar b$ quarks and neglecting heavy spin effects. Since
the binding energy is of the same order as expected for these heavy spin
effects, it is essential to include them in the computation. Here we present a
corresponding method and show evidence that binding is only slightly weakened
and that the $\bar b \bar b u d$ tetraquark persists.


title: Universal decoding using a noisy codebook

abstract:
  We consider the topic of universal decoding with a decoder that does not have
direct access to the codebook, but only to noisy versions of the various
randomly generated codewords, a problem motivated by biometrical identification
systems. Both the source that generates the original (clean) codewords, and the
channel that corrupts them in generating the noisy codewords, as well as the
main channel for communicating the messages, are all modeled by non-unifilar,
finite-state systems (hidden Markov models). As in previous works on universal
decoding, here too, the average error probability of our proposed universal
decoder is shown to be as small as that of the optimal maximum likelihood (ML)
decoder, up to a multiplicative factorthat is a sub-exponential function of the
block length. It therefore has the same error exponent, whenever the ML decoder
has a positive error exponent. The universal decoding metric is based on
Lempel-Ziv (LZ) incremental parsing of each noisy codeword jointly with the
given channel output vector, but this metric is somewhat different from the one
proposed in earlier works on universal decoding for finite-state channels, by
Ziv (1985) and by Lapidoth and Ziv (1998). The reason for the difference is
that here, unlike in those earlier works, the probability distribution that
governs the (noisy) codewords is, in general, not uniform across its support.
This non-uniformity of the codeword distribution also makes our derivation more
challenging. Another reason for the more challenging analysis is the fact that
the effective induced channel between the noisy codeword of the transmitted
message and the main channel output is not a finite-state channel in general.


title: Pressure profiles of nonuniform two-dimensional atomic Fermi gases

abstract:
  Spatial profiles of the pressure have been measured in atomic Fermi gases
with primarily 2D kinematics. The in-plane motion of the particles is confined
by a gaussian-shape potential. The two-component deeply-degenerate Fermi gases
are prepared at different values of the s-wave attraction. The pressure profile
is found using the force-balance equation, from the measured density profile
and the trapping potential. The pressure is compared to zero-temperature models
within the local density approximation. In the weakly-interacting regime, the
pressure lies above a Landau Fermi-liquid theory and below the ideal-Fermi-gas
model, whose prediction coincides with that of the Cooper-pair mean-field
theory. The values closest to the data are provided by the approach where the
mean-field of Cooper pairs is supplemented with fluctuations. In the regime of
strong interactions, in response to the increasing attraction, the pressure
shifts below this model reaching lower values calculated within Monte Carlo
methods. Comparison to models shows that interaction-induced departure from 2D
kinematics is either small or absent. In particular, comparison with a lattice
Monte Carlo suggests that kinematics is 2D in the strongly-interacting regime.


title:
Detection of exposed H$_2$O ice on the nucleus of comet
  67P/Churyumov-Gerasimenko

abstract:
  Since the orbital insertion of the Rosetta spacecraft, comet
67P/Churyumov-Gerasimenko (67P/C-G) has been mapped by OSIRIS camera and VIRTIS
spectro-imager, producing a huge quantity of images and spectra of the comet's
nucleus. The aim of this work is to search for the presence of H$_2$O on the
nucleus which, in general, appears very dark and rich in dehydrated organic
material. After selecting images of the bright spots which could be good
candidates to search for H$_2$O ice, taken at high resolution by OSIRIS, we
check for spectral cubes of the selected coordinates to identify these spots
observed by VIRTIS. The selected OSIRIS images were processed with the OSIRIS
standard pipeline and corrected for the illumination conditions for each pixel
using the Lommel-Seeliger disk law. The spots with higher I/F were selected and
then analysed spectrophotometrically and compared with the surrounding area. We
selected 13 spots as good targets to be analysed by VIRTIS to search for the 2
micron absorption band of water ice in the VIRTIS spectral cubes. Out of the 13
selected bright spots, eight of them present positive H$_2$O ice detection on
the VIRTIS data. A spectral analysis was performed and the approximate
temperature of each spot was computed. The H$_2$O ice content was confirmed by
modeling the spectra with mixing (areal and intimate) of H$_2$O ice and dark
terrain, using Hapke's radiative transfer modeling. We also present a detailed
analysis of the detected spots.


title:
Incorporating Clicks, Attention and Satisfaction into a Search Engine
  Result Page Evaluation Model

abstract:
  Modern search engine result pages often provide immediate value to users and
organize information in such a way that it is easy to navigate. The core
ranking function contributes to this and so do result snippets, smart
organization of result blocks and extensive use of one-box answers or side
panels. While they are useful to the user and help search engines to stand out,
such features present two big challenges for evaluation. First, the presence of
such elements on a search engine result page (SERP) may lead to the absence of
clicks, which is, however, not related to dissatisfaction, so-called "good
abandonments." Second, the non-linear layout and visual difference of SERP
items may lead to non-trivial patterns of user attention, which is not captured
by existing evaluation metrics.
  In this paper we propose a model of user behavior on a SERP that jointly
captures click behavior, user attention and satisfaction, the CAS model, and
demonstrate that it gives more accurate predictions of user actions and
self-reported satisfaction than existing models based on clicks alone. We use
the CAS model to build a novel evaluation metric that can be applied to
non-linear SERP layouts and that can account for the utility that users obtain
directly on a SERP. We demonstrate that this metric shows better agreement with
user-reported satisfaction than conventional evaluation metrics.


title: Semi-classical Time-frequency Analysis and Applications

abstract:
  This work represents a first systematic attempt to create a common ground for
semi-classical and time-frequency analysis. These two different areas combined
together provide interesting outcomes in terms of Schr\"odinger type equations.
Indeed, continuity results of both Schr\"odinger propagators and their
asymptotic solutions are obtained on $\hbar$-dependent Banach spaces, the
semi-classical version of the well-known modulation spaces. Moreover, their
operator norm is controlled by a constant independent of the Planck's constant
$\hbar$. The main tool in our investigation is the joint application of
standard approximation techniques from semi-classical analysis and a
generalized version of Gabor frames, dependent of the parameter $\hbar$.
Continuity properties of more general Fourier integral operators (FIOs) and
their sparsity are also investigated.


title:
On Jensen's inequality for generalized Choquet integral with an
  application to risk aversion

abstract:
  In the paper we give necessary and sufficient conditions for the Jensen
inequality to hold for the generalized Choquet integral with respect to a pair
of capacities. Next, we apply obtained result to the theory of risk aversion by
providing the assumptions on utility function and capacities under which an
agent is risk averse. Moreover, we show that the Arrow-Pratt theorem can be
generalized to cover the case, where the expectation is replaced by the
generalized Choquet integral.


title: Quantum emitter dipole-dipole interactions in nanoplasmonic systems

abstract:
  We introduce a generalized Dicke-like model to describe two-level systems
coupled with a single bosonic mode. In addition, the two-level systems mutually
interact via direct dipole-dipole interaction. We apply the model to an
ensemble of dye molecules coupled to a plasmonic excitation in a metallic
nanoparticle and study how the dipole-dipole interaction and configurational
randomness introduced to the system affect the energy spectra. Comparing the
system eigenenergies obtained by our model with the light spectra from a
multiple-scattering simulation, we suggest a way to identify dark modes in our
model. Finally, we perform a parameter sweep in order to determine the scaling
properties of the system and to classify the regions of the parameter space
where the dipole-dipole interactions can have significant effects.


title:
Marginally stable and turbulent boundary layers in low-curvature
  Taylor-Couette flow

abstract:
  Marginal stability arguments are used to describe the rotation-number
dependence of torque in Taylor-Couette (TC) flow for radius ratios $\eta \geq
0.9$ and shear Reynolds number $Re_S=2\times 10^4$. With an approximate
representation of the mean profile by piecewise linear functions, characterized
by the boundary-layer thicknesses at the inner and outer cylinder and the
angular momentum in the center, profiles and torques are extracted from the
requirement that the boundary layers represent marginally stable TC subsystems
and that the torque at the inner and outer cylinder coincide. This model then
explains the broad shoulder in the torque as a function of rotation number near
$R_\Omega\approx 0.2$. For rotation numbers $R_\Omega < 0.07$ the TC stability
conditions predict boundary layers in which shear Reynolds numbers are very
large. Assuming that the TC instability is bypassed by some shear instability,
a second maximum in torque appears, in very good agreement with numerical
simulations. The results show that, despite the shortcomings of marginal
stability theory in other cases, it can explain quantitatively the
non-monotonic torque variation with rotation number for both the broad maximum
as well as the narrow maximum.


title:
Non-equilibrium fluctuations of a semi-flexible filament driven by
  active cross-linkers

abstract:
  The cytoskeleton is an inhomogeneous network of semi-flexible filaments,
which are involved in a wide variety of active biological processes. Although
the cytoskeletal filaments can be very stiff and embedded in a dense and
cross-linked network, it has been shown that, in cells, they typically exhibit
significant bending on all length scales. In this work we propose a model of a
semi-flexible filament deformed by different types of cross-linkers for which
one can compute and investigate the bending spectrum. Our model allows to
couple the evolution of the deformation of the semi-flexible polymer with the
stochastic dynamics of linkers which exert transversal forces onto the
filament. We observe a $q^{-2}$ dependence of the bending spectrum for some
biologically relevant parameters and in a certain range of wavenumbers $q$.
However, generically, the spatially localized forcing and the non-thermal
dynamics both introduce deviations from the thermal-like $q^{-2}$ spectrum.


title:
Monte Carlo Simulation of the Crossover from Bose Glass to Bragg Glass
  Phase in Layered BSCCO with Columnar Defects

abstract:
  Monte Carlo simulations of layered BSCCO samples are used to investigate the
behavior of vortex matter at low fields, particularly in connection with the
possible occurrence of a Bragg glass (BrG) phase at low density of columnar
defects, a phenomenon characterized by the prevalence of short-range over
long-range order. In this dislocation-free topological phase the translational
order correlation function displays a power law decay. For magnetic induction
$B=0.1$ kG the analysis of the data for the first Bragg peak of the planar
structure factor, the hexatic order parameter, and the Delaunay triangulation
shows that, as the density of columnar defects is lowered, a \textit{crossover}
(or transition) from Bose glass to BrG phase takes place in this \textit{highly
anisotropic} high-T${}_c$ superconductor. Most importantly, an analysis of the
{low-temperature} 3D vortex-vortex correlation function in terms of the
structure factor, calculated via a saddle point approach and the use of the
numerical data as input, provides clear-cut evidence of {the} power law decay
of the {divergent} Bragg peaks in the BrG phase, a fundamental feature that was
inequivocally verified only in isotropic compounds.


title:
Improving Correlation with Human Judgments by Integrating Semantic
  Similarity with Second--Order Vectors

abstract:
  Vector space methods that measure semantic similarity and relatedness often
rely on distributional information such as co--occurrence frequencies or
statistical measures of association to weight the importance of particular
co--occurrences. In this paper, we extend these methods by incorporating a
measure of semantic similarity based on a human curated taxonomy into a
second--order vector representation. This results in a measure of semantic
relatedness that combines both the contextual information available in a
corpus--based vector space representation with the semantic knowledge found in
a biomedical ontology. Our results show that incorporating semantic similarity
into a second order co--occurrence matrices improves correlation with human
judgments for both similarity and relatedness, and that our method compares
favorably to various different word embedding methods that have recently been
evaluated on the same reference standards we have used.


title:
The simplest microscopic model of a complex fluid: flow phenomena and
  constitutive relation

abstract:
  It was shown in [PRL 114, 138301 (2015)] that a remarkably simple dynamical
model exhibits many of the complex flow regimes and non-equilibrium phase
transitions characteristic of complex fluids. By removing extraneous detail,
this simplest microscopic model of non-Newtonian flow can reveal the universal
physics relevant to all complex fluids. Here we present more detailed results
and a full derivation of the model's compact mean-field constitutive relation,
with great potential scope for insights into universality and tractable
mathematics. By enforcing local conservation of angular momentum, the
one-dimensional (1D) XY-model (originally used for equilibrium magnetic
systems) can be driven into various flow regimes, including simple Newtonian
behaviour, shear banding, solid-liquid coexistence and slip-plane motion. The
model demonstrates that the phenomenon of shear banding does not rely on
details of tensorial stress fields, but can exist in 1D.


title:
Room-temperature transport properties of spin-orbit coupled Fermi
  systems: Spin thermoelectric effects, phonon skew scattering

abstract:
  In this note we summarize our recent results for the temperature dependence
of transport coefficients of metallic films in the presence of spin-orbit
coupling. Our focus is on (i) the spin Nernst and the thermal Edelstein
effects, and (ii) the phonon skew scattering contribution to the spin Hall
conductivity, which is relevant for the temperature dependence of the spin Hall
angle. Depending on the parameters, the latter is expected to show a
non-monotonous behavior.


title: Polaritonic linear dynamic in Keldysh formalism

abstract:
  We study the dynamic of polaritons in the Keldysh functional formalism.
Dissipation is considered through the coupling of the exciton and photon fields
to two independent photonic and excitonic baths. As such, this theory allows to
describe more intricate decay mechanisms that depend dynamically on the state
of the system, such as a direct upper-polariton lifetime, that is motivated
from experiments. We show that the dynamical equations in the Keldysh framework
otherwise follow the same Josephson--like equations of motions than the
standard master equation approach, that is however limited to simple decay
channels. We also discuss the stability of the dynamic and reconsider the
criterion of strong coupling in the presence of upper polariton decay.


title:
Asymptotically optimal priority policies for indexable and nonindexable
  restless bandits

abstract:
  We study the asymptotic optimal control of multi-class restless bandits. A
restless bandit is a controllable stochastic process whose state evolution
depends on whether or not the bandit is made active. Since finding the optimal
control is typically intractable, we propose a class of priority policies that
are proved to be asymptotically optimal under a global attractor property and a
technical condition. We consider both a fixed population of bandits as well as
a dynamic population where bandits can depart and arrive. As an example of a
dynamic population of bandits, we analyze a multi-class $\mathit{M/M/S+M}$
queue for which we show asymptotic optimality of an index policy. We combine
fluid-scaling techniques with linear programming results to prove that when
bandits are indexable, Whittle's index policy is included in our class of
priority policies. We thereby generalize a result of Weber and Weiss [J. Appl.
Probab. 27 (1990) 637-648] about asymptotic optimality of Whittle's index
policy to settings with (i) several classes of bandits, (ii) arrivals of new
bandits and (iii) multiple actions. Indexability of the bandits is not required
for our results to hold. For nonindexable bandits, we describe how to select
priority policies from the class of asymptotically optimal policies and present
numerical evidence that, outside the asymptotic regime, the performance of our
proposed priority policies is nearly optimal.


title:
Heat conduction in a chain of colliding particles with stiff repulsive
  potential

abstract:
  One-dimensional billiard, i.e. a chain of colliding particles with equal
masses, is well-known example of completely integrable system. Billiards with
different particles are generically not integrable, but still exhibit
divergence of a heat conduction coefficient (HCC) in thermodynamic limit.
Traditional billiard models imply instantaneous (zero-time) collisions between
the particles. We lift this condition and consider the heat transport in a
chain of stiff colliding particles with power-law potential of the
nearest-neighbor interaction. The instantaneous collisions correspond to the
limit of infinite power in the interaction potential; for finite powers, the
interactions take nonzero time. This modification of the model leads to
profound physical consequence -- probability of multiple, in particular, triple
particle collisions becomes nonzero. Contrary to the integrable billiard of
equal particles, the modified model exhibits saturation of the heat conduction
coefficient for large system size. Moreover, identification of scattering
events with the triple particle collisions leads to simple definition of
characteristic mean free path and kinetic description of the heat transport.
This approach allows prediction both of temperature and density dependencies
for the HCC limit values. The latter dependence is quite counterintuitive - the
HCC is inversely proportional to the particle density in the chain. Both
predictions are confirmed by direct numeric simulations.


title:
Skipping Word: A Character-Sequential Representation based Framework for
  Question Answering

abstract:
  Recent works using artificial neural networks based on word distributed
representation greatly boost the performance of various natural language
learning tasks, especially question answering. Though, they also carry along
with some attendant problems, such as corpus selection for embedding learning,
dictionary transformation for different learning tasks, etc. In this paper, we
propose to straightforwardly model sentences by means of character sequences,
and then utilize convolutional neural networks to integrate character embedding
learning together with point-wise answer selection training. Compared with deep
models pre-trained on word embedding (WE) strategy, our character-sequential
representation (CSR) based method shows a much simpler procedure and more
stable performance across different benchmarks. Extensive experiments on two
benchmark answer selection datasets exhibit the competitive performance
compared with the state-of-the-art methods.


title:
A comparison between pretriangulated $\mbox{A}_{\infty}$-categories and
  $\infty$-Stable categories

abstract:
  In this paper we will prove that the $\mbox{A}_{\infty}$-nerve of two
quasi-equivalent $\mbox{A}_{\infty}$-categories are weak-equivalent in the
Joyal model structure, a consequence of this fact is that the
$\mbox{A}_{\infty}$-nerve of a pretriangulated $\mbox{A}_{\infty}$-category is
$\infty$-stable. Moreover we give a comparison between the notions of
pretriangulated $\mbox{A}_{\infty}$-categories, pretriangulated dg-categories
and $\infty$-stable categories.


title:
Orbital angular momentum complex spectrum analyzer for vortex light
  based on rotational Doppler Effect

abstract:
  The function to measure orbital angular momentum (OAM) distribution of vortex
light is essential for OAM applications. Although there are lots of works to
measure OAM modes, it is difficult to measure the power distribution of
different OAM modes quantitatively and instantaneously, let alone measure the
phase distribution among them. In this work, we demonstrate an OAM complex
spectrum analyzer, which enables to measure the power and phase distribution of
OAM modes simultaneously by employing rotational Doppler Effect. The original
OAM mode distribution is mapped to electrical spectrum of beating signals with
a photodetector. The power distribution and phase distribution of superimposed
OAM beams are successfully retrieved by analyzing the electrical spectrum. We
also extend the measurement to other spatial modes, such as linear polarization
modes. These results represent a new landmark of spatial mode analysis and show
great potentials in optical communication and OAM quantum state tomography.


title:
16CygA&B and Kepler Legacy values : Differences between the values of
  frequencies by different fitters

abstract:
  The differences between the oscillation frequencies and uncertainty estimates
of a star derived by different fitters can be large, sufficiently large so
that, were one to find a stellar model that fitted one frequency set
($\chi^2\sim 1$), it does not fit an alternative set. I give 21 examples,
comparing frequency sets in common between the Kepler Legacy project and
frequency sets from Appourchaux et al (2014) and Davies et al (2015). For
16CygA&B the differences are large; the $\chi^2$ of the fit of Legacy to
Davies's values ranging from 1.64 to 11.47 for 16CygA and 1.62 to 1.79 for
16CygB, depending on which error estimates are used. I analyse both stars in
some detail applying my own mode fitting code to both the Legacy and Davies's
power spectra and find reasonable agreement with Davies's full frequency sets
and very good agreement between values for modes with signal/noise > 1 ($\chi^2
= 0.06, \chi^2_B=0.03$). But the difference with the Legacy values remains
large even for modes with S/N>1. I also examine the effects of different power
spectra (weighted and unweighted) using the kasoc light curves for Q6-17.2 and
Q7-Q16, the effect of different mode height ratios and different rotational
splitting and inclination.


title:
Dependence of the Sunspot-group Size on the Level of Solar Activity and
  its Influence on the Calibration of Solar Observers

abstract:
  The distribution of the sunspot group size (area) and its dependence on the
level of solar activity is studied. It is shown that the fraction of small
groups is not constant but decreases with the level of solar activity so that
high solar activity is largely defined by big groups. We study the possible
influence of solar activity on the ability of a realistic observer to see and
report the daily number of sunspot groups. It is shown that the relation
between the number of sunspot groups as seen by different observers with
different observational acuity thresholds is strongly non-linear and cannot be
approximated by the traditionally used linear scaling ($k-$factors). The
observational acuity threshold [$A_{\rm th}$] is considered to quantify the
quality of each observer, instead of the traditional relative $k-$factor. A
nonlinear $c-$factor based on $A_{\rm th}$ is proposed, which can be used to
correct each observer to the reference conditions. The method is tested on a
pair of principal solar observers, Wolf and Wolfer, and it is shown that the
traditional linear correction, with the constant $k-$factor of 1.66 to scale
Wolf to Wolfer, leads to an overestimate of solar activity around solar maxima.


title: Surfaces expanding by non-concave curvature functions

abstract:
  In this paper, we first investigate the flow of convex surfaces in the space
form $\mathbb{R}^3(\kappa)~(\kappa=0,1,-1)$ expanding by $F^{-\alpha}$, where
$F$ is a smooth, symmetric, increasing and homogeneous of degree one function
of the principal curvatures of the surfaces and the power $\alpha\in(0,1]$ for
$\kappa=0,-1$ and $\alpha=1$ for $\kappa=1$. By deriving that the pinching
ratio of the flow surface $M_t$ is no greater than that of the initial surface
$M_0$, we prove the long time existence and the convergence of the flow. No
concavity assumption of $F$ is required. We also show that for the flow in
$\mathbb{H}^3$ with $\alpha\in (0,1)$, the limit shape may not be necessarily
round after rescaling.


title: A Note on convergence of double sequences in a topological space

abstract:
  In this paper we have shown that a double sequence in a topological space
satisfies certain conditions which in turn are capable to generate a topology
on a non empty set. Also we have used the idea of I-convergence of double
sequences to study the idea of I-sequentially compactness [3] in the sense of
double sequences.


title: Conformal Bootstrap in Mellin Space

abstract:
  We propose a new approach towards analytically solving for the dynamical
content of Conformal Field Theories (CFTs) using the bootstrap philosophy. This
combines the original bootstrap idea of Polyakov with the modern technology of
the Mellin representation of CFT amplitudes. We employ exchange Witten diagrams
with built in crossing symmetry as our basic building blocks rather than the
conventional conformal blocks in a particular channel. Demanding consistency
with the operator product expansion (OPE) implies an infinite set of
constraints on operator dimensions and OPE coefficients. We illustrate the
power of this method in the epsilon expansion of the Wilson-Fisher fixed point
by reproducing anomalous dimensions and, strikingly, obtaining OPE coefficients
to higher orders in epsilon than currently available using other analytic
techniques (including Feynman diagram calculations). Our results enable us to
get a somewhat better agreement of certain observables in the 3d Ising model,
with the precise numerical values that have been recently obtained.

categories: hep-th cond-mat.stat-mech cond-mat.str-el hep-ph


title: Circulant preconditioners for discrete ill-posed Toeplitz systems

abstract:
  Circulant preconditioners are commonly used to accelerate the rate of
convergence of iterative methods when solving linear systems of equations with
a Toeplitz matrix. Block extensions that can be applied when the system has a
block Toeplitz matrix with Toeplitz blocks also have been developed. This paper
is concerned with preconditioning of linear systems of equations with a
symmetric block Toeplitz matrix with symmetric Toeplitz blocks that stem from
the discretization of a linear ill-posed problem. The right-hand side of the
linear systems represents available data and is assumed to be contaminated by
error. These kinds of linear systems arise, e.g., in image deblurring problems.
It is important that the preconditioner does not affect the invariant subspace
associated with the smallest eigenvalues of the block Toeplitz matrix to avoid
severe propagation of the error in the right-hand side. A perturbation result
indicates how the dimension of the subspace associated with the smallest
eigenvalues should be chosen and allows the determination of a suitable
preconditioner when an estimate of the error in the right-hand side is
available. This estimate also is used to decide how many iterations to carry
out by a minimum residual iterative method. Applications to image restoration
are presented.


title: Pathologies on Mori fibre spaces in positive characteristic

abstract:
  We show that there exist Mori fibre spaces whose total spaces are klt but
bases are not. We also construct Mori fibre spaces which have relatively
non-trivial torsion line bundles.


title: On the nature of bright compact radio sources at z>4.5

abstract:
  High-redshift radio-loud quasars are used to, among other things, test the
predictions of cosmological models, set constraints on black hole growth in the
early universe and understand galaxy evolution. Prior to this paper, 20
extragalactic radio sources at redshifts above 4.5 have been imaged with very
long baseline interferometry (VLBI). Here we report on observations of an
additional ten z>4.5 sources at 1.7 and 5 GHz with the European VLBI Network
(EVN), thereby increasing the number of imaged sources by 50%. Combining our
newly observed sources with those from the literature, we create a substantial
sample of 30 z>4.5 VLBI sources, allowing us to study the nature of these
objects. Using spectral indices, variability and brightness temperatures, we
conclude that of the 27 sources with sufficient information to classify, the
radio emission from one source is from star formation, 13 are flat-spectrum
radio quasars and 13 are steep-spectrum sources. We also argue that the
steep-spectrum sources are off-axis (unbeamed) radio sources with rest-frame
self-absorption peaks at or below GHz frequencies and that these sources can be
classified as gigahertz peaked-spectrum (GPS) and megahertz peaked-spectrum
(MPS) sources.


title: Semigroups of isometries of the hyperbolic plane

abstract:
  Motivated by a problem on the dynamics of compositions of plane hyperbolic
isometries, we prove several fundamental results on semigroups of isometries,
thought of as real M\"obius transformations. We define a semigroup $S$ of
M\"obius transformations to be \emph{semidiscrete} if the identity
transformation is not an accumulation point of $S$. We say that $S$ is
\emph{inverse free} if it does not contain the identity element. One of our
main results states that if $S$ is a semigroup generated by some finite
collection $\mathcal{F}$ of M\"obius transformations, then $S$ is semidiscrete
and inverse free if and only if every sequence of the form $F_n=f_1\dotsb f_n$,
where $f_n\in\mathcal{F}$, converges pointwise on the upper half-plane to a
point on the ideal boundary, where convergence is with respect to the chordal
metric on the extended complex plane. We fully classify all two-generator
semidiscrete semigroups, and include a version of J{\o}rgensen's inequality for
semigroups.
  We also prove theorems that have familiar counterparts in the theory of
Fuchsian groups. For instance, we prove that every semigroup is one of four
standard types: elementary, semidiscrete, dense in the M\"obius group, or
composed of transformations that fix some nontrivial subinterval of the
extended real line. As a consequence of this theorem, we prove that, with
certain minor exceptions, a finitely-generated semigroup $S$ is semidiscrete if
and only if every two-generator semigroup contained in $S$ is semidiscrete.
  After this we examine the relationship between the size of the `group part'
of a semigroup and the intersection of its forward and backward limit sets. In
particular, we prove that if $S$ is a finitely-generated nonelementary
semigroup, then $S$ is a group if and only if its two limit sets are equal.
  We finish by applying some of our methods to address an open question of
Yoccoz.


title: Generic Inference in Latent Gaussian Process Models

abstract:
  We develop an automated variational method for inference in models with
Gaussian process (GP) priors and general likelihoods. The method supports
multiple outputs and multiple latent functions and does not require detailed
knowledge of the conditional likelihood, only needing its evaluation as a
black-box function. Using a mixture of Gaussians as the variational
distribution, we show that the evidence lower bound and its gradients can be
estimated efficiently using samples from univariate Gaussian distributions.
Furthermore, the method is scalable to large datasets which is achieved by
using an augmented prior via the inducing-variable approach underpinning most
sparse GP approximations, along with parallel computation and stochastic
optimization. We evaluate our approach quantitatively and qualitatively with
experiments on small datasets, medium-scale datasets and large datasets,
showing its competitiveness under different likelihood models and sparsity
levels. On the large-scale experiments involving prediction of airline delays
and classification of handwritten digits, we show that our method is on par
with the state-of-the-art hard-coded approaches for scalable GP regression and
classification.


title:
Seismic Wave Amplification in 3D Alluvial Basins: 3D/1D Amplification
  Ratios from Fast Multipole BEM Simulations

abstract:
  In this work, we study seismic wave amplification in alluvial basins having
3D standard geometries through the Fast Multipole Boundary Element Method in
the frequency domain. We investigate how much 3D amplification differs from the
1D (horizontal layering) case. Considering incident fields of plane harmonic
waves, we examine the relationships between the amplification level and the
most relevant physical parameters of the problem (impedance contrast, 3D aspect
ratio, vertical and oblique incidence of plane waves). The FMBEM results show
that the most important parameters for wave amplification are the impedance
contrast and the so-called equivalent shape ratio. Using these two parameters,
we derive simple rules to compute the fundamental frequency for various 3D
basin shapes and the corresponding 3D/1D amplification factor for 5% damping.
Effects on amplification due to 3D basin asymmetry are also studied and
incorporated in the derived rules.


title:
Modelling Geomechanical Impact of CO2 Injection Using Precomputed
  Response Functions

abstract:
  When injecting CO2 or other fluids into a geological formation, pressure
plays an important role both as a driver of flow and as a risk factor for
mechanical integrity.
  The full effect of geomechanics on aquifer flow can only be captured using a
coupled flow-geomechanics model. In order to solve this computationally
expensive system, various strategies have been put forwards over the years,
with some of the best current methods based on sequential splitting.
  In the present work, we seek to approximate the full geomechanical effect on
flow without the need of coupling with a geomechanics solver during simulation,
and at a computational cost comparable to that of an uncoupled model. We do
this by means of precomputed pressure response functions. At grid model
generation time, a geomechanics solver is used to compute the mechanical
response of the aquifer for a set of pressure fields. The relevant information
from these responses is then stored in a compact form and embedded with the
grid model.
  We test the accuracy and computational performance of our approach on a
simple 2D and a more complex 3D model, and compare the results with those
produced by a fully coupled approach as well as from a simple decoupled method
based on Geertsma's uniaxial expansion coefficient.


title:
Approach to the steady state in kinetic models with thermal reservoirs
  at different temperatures

abstract:
  We continue the investigation of kinetic models of a system in contact via
stochastic interactions with several spatially homogeneous thermal reservoirs
at different temperatures. Considering models different from those investigated
in earlier work, we explicitly compute the unique spatially uniform
non-equilibrium steady state (NESS) and prove that it is approached
exponentially fast from any uniform initial state. This leaves open the
question of whether there exist NESS that are not spatially uniform. Making a
further simplification of our models, we then prove non-existence of such NESS
and exponential approach to the unique spatially uniform NESS (with a
computably boundable rate). The method of proof relies on refined Doeblin
estimates and other probabilisitic techniques, and is quite different form the
analysis in earlier work that was based on contraction mapping methods.


title: $AB$-algorithm and its application for solving matrix square roots

abstract:
  This work is to propose an iterative method of choice to compute a stable
subspace of a regular matrix pencil. This approach is to define a sequence of
matrix pencils via particular left null spaces. We show that this iteration
preserves a discrete-type flow depending only on the initial matrix pencil. Via
this recursion relationship, we propose an accelerated iterative method to
compute the stable subspace and use it to provide a theoretical result to solve
the principal square root of a given matrix, both nonsingular and singular. We
show that this method can not only find out the matrix square root, but also
construct an iterative approach which converges to the square root with any
desired order.


title:
Stochastic affine evolution equations with multiplicative fractional
  noise

abstract:
  A stochastic affine evolution equation with bilinear noise term is studied
where the driving process is a real-valued fractional Brownian motion.
Stochastic integration is understood in the Skorokhod sense. Existence and
uniqueness of weak solution is proved and some results on the large time
dynamics are obtained


title:
Analysis of the Fourier series Dirichlet-to-Neumann boundary condition
  of the Helmholtz equation and its application to finite element methods

abstract:
  It is well known that the Fourier series Dirichlet-to-Neumann (DtN) boundary
condition can be used to solve the Helmholtz equation in unbounded domains. In
this work, applying such DtN boundary condition and using the finite element
method, we solve and analyze a two dimensional transmission problem describing
elastic waves inside a bounded and closed elastic obstacle and acoustic waves
outside it. We are mainly interested in analyzing the DtN boundary condition of
the Helmholtz equation in order to establish the well-posedness results of the
approximated variational equation, and further derive a priori error estimates
involving effects of both the finite element discretization and the DtN
boundary condition truncation. Finally, some numerical results are presented to
illustrate the accuracy of the numerical scheme.


title: A Theory of Shape-Shifting Droplets

abstract:
  Recent studies of cooled oil emulsion droplets uncovered transformations into
a host of flattened shapes with straight edges and sharp corners, driven by a
partial phase transition of the bulk liquid phase. Here, we explore
theoretically the simplest geometric competition between this phase transition
and surface tension in planar polygons, and recover the observed sequence of
shapes and their statistics in qualitative agreement with experiments.
Extending the model to capture some of the three-dimensional structure of the
droplets, we analyze the evolution of protrusions sprouting from the vertices
of the platelets and the topological transition of a puncturing planar polygon.


title:
Doubly stochastic large scale kernel learning with the empirical kernel
  map

abstract:
  With the rise of big data sets, the popularity of kernel methods declined and
neural networks took over again. The main problem with kernel methods is that
the kernel matrix grows quadratically with the number of data points. Most
attempts to scale up kernel methods solve this problem by discarding data
points or basis functions of some approximation of the kernel map. Here we
present a simple yet effective alternative for scaling up kernel methods that
takes into account the entire data set via doubly stochastic optimization of
the emprical kernel map. The algorithm is straightforward to implement, in
particular in parallel execution settings; it leverages the full power and
versatility of classical kernel functions without the need to explicitly
formulate a kernel map approximation. We provide empirical evidence that the
algorithm works on large data sets.


title: Chemical Propagation Pattern for Molecular Communications

abstract:
  In a diffusion-based molecular communication system, molecules are employed
to convey information. When propagation and reception processes are considered
in a framework of first passage processes, we need to focus on absorbing
receivers. For this kind of molecular communication system, the characteristics
of the channel is also affected by the shape of the transmitter. In the
literature, most studies focus on systems with a point transmitter due to
circular symmetry. In this letter, we address propagation and reception pattern
for chemical signals emitted from a spherical transmitter. We also investigate
the directivity gain achieved by the reflecting spherical transmitter. We
quantify the power gain by measuring the received power at different angles on
a circular region. Moreover, we define three metrics, i.e., the half-power
pattern-width, the directivity gain, and the peak time of the signal, for
analyzing the received signal pattern.


title: On long term investment optimality

abstract:
  We study the problem of optimal long term portfolio selection with a view to
beat a benchmark. Two kinds of objectives are considered. One concerns the
probability of outperforming the benchmark and seeks either to minimise the
decay rate of the probability that the portfolio exceeds the benchmark or to
maximise the decay rate that the portfolio falls short. The other criterion
concerns the growth rate of the risk-sensitive utility of wealth which has to
be either minimised, for the risk-averse investor, or maximised, for the
risk-seeking investor. It is assumed that the mean returns and volatilities of
the securities are affected by an economic factor, possibly, in a nonlinear
fashion. The economic factor and the benchmark are modelled with general It\^o
differential equations. The results identify optimal portfolios and produce
decay, or growth, rates. The portfolios have the form of time-homogeneous
functions of the economic factor. Furthermore, a uniform treatment is given to
the out- and under- performance probability optimisation as well as to the
risk-averse and risk-seeking optimisation. In particular, it is shown that
there exists a portfolio that optimises the decay rates of both the
outperfomance probability and the underperformance probability. Whereas earlier
research on the subject has relied on the techniques of stochastic optimal
control and dynamic programming, in this contribution the quantities of
interest are studied directly by employing the methods of the large deviation
theory. The key to the analysis is to recognise the setup in question as a case
of coupled diffusions with time scale separation, with the economic factor
representing "the fast process".


title: Upper bounds for dominant dimensions of gendo-symmetric algebras

abstract:
  The famous Nakayama conjecture states that the dominant dimension of a
non-selfinjective finite dimensional algebra is finite. In \cite{Yam}, Yamagata
stated the stronger conjecture that the dominant dimension of a
non-selfinjective finite dimensional algebra is bounded by a function depending
on the number of simple modules of that algebra. With a view towards those
conjectures, new bounds on dominant dimensions seem desirable. We give a new
approach to bounds on the dominant dimension of gendo-symmetric algebras via
counting non-isomorphic indecomposable summands of rigid modules in the module
category of those algebras. On the other hand, by Mueller's theorem, the
calculation of dominant dimensions is directly related to the calculation of
certain Ext-groups. Motivated by this connection, we generalize a theorem of
Tachikawa about non-vanishing of $Ext^{1}(M,M)$ for a non-projective module $M$
in group algebras of $p$-groups to local Hopf algebras and we also give new
results for showing the non-vanishing of $Ext^{1}(M,M)$ for certain modules in
other local selfinjective algebras, which specializes to show that blocks of
category $\mathcal{O}$ and 1-quasi-hereditary algebras with a special duality
have dominant dimension exactly 2. In the final section we raise different
questions with the hope of a new developement on those conjectures in the
future.


title: Dynamical fluid-type Universe scenario with dust and radiation

abstract:
  Within the context of a cosmic space whose energy source is modeled with a
perfect fluid, a uniform model of Universe based on a standard FRW cosmology
containing decoupled mixed matter sources namely stiff matter and cosmic dust
together with a positive cosmological constant, has been studied. Within the
scenario of a $k=0-$ spatially-flat geometry, we analysed the geometrodynamics
of the theoretical cosmology. For the model with an added cosmological
constant, the main scope was to point out the effects of it on the universe'
dynamics. In this last case, the thermodynamics of the model was also
considered together with the relation between the cosmological energy density
and fluid pressure in terms of the inverse function of the equation of state.


title:
Towards quantum entanglement of micromirrors via a two-level atom and
  radiation pressure

abstract:
  We propose a method to entangle two distant vibrating microsize mirrors
(i.e., mechanical oscillators) in a cavity optomechanical system. In this
scheme, we discuss both the resonant and large-detuning conditions, and show
that the entanglement of two mechanical oscillators can be achieved with the
assistance of a two-level atom and cavity-radiation pressure. In the resonant
case, the operation time is relatively short, which is desirable to minimize
the effects of decoherence. While in the large-detuning case, the cavity is
only virtually excited during the interaction. Therefore, the decay of the
cavity is effectively suppressed, which makes the efficient decoherence time of
the cavity to be greatly prolonged. Thus, we observe that this virtual-photon
process of microscopic objects may induce the entanglement of macroscopic
objects. Moreover, in both cases, the generation of entanglement is
deterministic and no measurements on the atom and the cavity are required.
These are experimentally important. Finally, the decoherence effect and the
experimental feasibility of the proposal are briefly discussed.


title:
Mirror graphs: graph theoretical characterization of reflection
  arrangements and finite Coxeter groups

abstract:
  Mirror graphs were introduced by Bre\v{s}ar et al. in 2004 as an intriguing
class of graphs: vertex-transitive, isometrically embeddable into hypercubes,
having a strong connection with regular maps and polytope structure. In this
article we settle the structure of mirror graphs by characterizing them as
precisely the Cayley graphs of the finite Coxeter groups or equivalently the
tope graphs of reflection arrangements - well understood and classified
structures. We provide a polynomial algorithm for their recognition.


title: 2D dynamics of the radiation zone of low mass stars

abstract:
  The internal rotation of low mass stars all along their evolution is of
primary interest when studying their rotational dynamics, internal mixing and
magnetic fields generation. In this context, helio- and asteroseismology probe
angular velocity gradients deep within solar type stars. Still the rotation of
the close center of such stars on the main sequence is hardly detectable and
the dynamical interactions of the radiative core with the surface convective
envelope is not well understood. Among them, the influence of the differential
rotation profile sustained by convection and applied as a boundary condition to
the radiation zone may be very important leading to the formation of
tachoclines. In the solar convective region, the equator is rotating faster
than the pole while numerical simulations predict either a solar or an
anti-solar rotation in other low mass stars envelopes depending on their
convective Rossby number. In this work, we therefore build for the first time
2D steady hydrodynamical models of low mass stars radiation zone providing a
full 2D description of their dynamics and studying the influence of a general
shear boundary condition accounting for a solar or an anti-solar differential
rotation in the convective envelope. We compute coherently differential
rotation and the associated meridional circulation using the Boussinesq
approximation.


title: The internal structure of overpressured, magnetized, relativistic jets

abstract:
  This work presents the first characterization of the internal structure of
overpressured steady superfast magnetosonic relativistic jets in connection
with their dominant type of energy. To this aim, relativistic
magnetohydrodynamic simulations of different jet models threaded by a helical
magnetic field have been analyzed covering a wide region in the magnetosonic
Mach number - specific internal energy plane. The merit of this plane is that
models dominated by different types of energy (internal energy: hot jets;
rest-mass energy: kinetically dominated jets; magnetic energy: Poynting-flux
dominated jets) occupy well separated regions. The analyzed models also cover a
wide range of magnetizations. Models dominated by the internal energy (i.e.,
hot models, or Poynting-flux dominated jets with magnetizations larger than but
close to 1) have a rich internal structure characterized by a series of
recollimation shocks and present the largest variations in the flow Lorentz
factor (and internal energy density). Conversely, in kinetically dominated
models there is not much internal nor magnetic energy to be converted into
kinetic one and the jets are featureless, with small variations in the flow
Lorentz factor. The presence of a significant toroidal magnetic field threading
the jet produces large gradients in the transversal profile of the internal
energy density. Poynting-flux dominated models with high magnetization (>10)
are prone to be unstable against magnetic pinch modes, which sets limits to the
expected magnetization in parsec-scale AGN jets {and/or constrains their
magnetic field configuration}.


title:
On Gaussian MACs with Variable-Length Feedback and Non-Vanishing
  Error~Probabilities

abstract:
  We characterize the fundamental limits of transmission of information over a
Gaussian multiple access channel (MAC) with the use of variable-length feedback
codes and under a non-vanishing error probability formalism. We develop new
achievability and converse techniques to handle the continuous nature of the
channel and the presence of expected power constraints. We establish the
$\varepsilon$-capacity regions and bounds on the second-order asymptotics of
the Gaussian MAC with variable-length feedback with termination (VLFT) codes
and stop-feedback codes. We show that the former outperforms the latter
significantly. Due to the multi-terminal nature of the channel model, we
leverage tools from renewal theory developed by Lai and Siegmund to bound the
asymptotic behavior of the maximum of a finite number of stopping times.


title: On the relations of isotonian algebras

abstract:
  It is shown that for large classes of posets $P$ and $Q$, the defining ideal
$J_{P,Q}$ of an isotonian algebras is generated by squarefree binomials. Within
these classes, those posets are classified for which $J_{P,Q}$ is quadratically
generated.


title: Abnormal oscillation modes in a waning light bridge

abstract:
  A sunspot acts as a waveguide in response to the dynamics of the solar
interior; the trapped waves and oscillations could reveal its thermal and
magnetic structures.
  We study the oscillations in a sunspot intruded by a light bridge, the
details of the oscillations could reveal the fine structure of the magnetic
topology.
  We use the Solar Dynamics Observatory/Atmospheric Imaging Assembly data to
analyse the oscillations in the emission intensity of light bridge plasma at
different temperatures and investigate their spatial distributions.
  The extreme ultraviolet emission intensity exhibits two persistent
oscillations at five-minute and sub-minute ranges. The spatial distribution of
the five-minute oscillation follows the spine of the bridge; whereas the
sub-minute oscillations overlap with two flanks of the bridge. Moreover, the
sub-minute oscillations are highly correlated in spatial domain, however, the
oscillations at the eastern and western flanks are asymmetric with regard to
the lag time. In the meanwhile, jet-like activities are only found at the
eastern flank.
  Asymmetries in forms of oscillatory pattern and jet-like activities
\textbf{are} found between two flanks of a granular light bridge. Based on our
study and recent findings, we propose a new model of twisted magnetic field for
a light bridge and its dynamic interactions with the magnetic field of a
sunspot.


title:
Influence of Cu deposition potential on the giant magnetoresistance and
  surface roughness of electrodeposited Ni-Co/Cu multilayers

abstract:
  It has been shown previously for electrodeposited Co/Cu multilayers that the
single-bath electrodeposition process can be optimized from an electrochemical
point of view in order to avoid unwanted Co dissolution and incorporation of Co
in the non-magnetic layer during the Cu deposition pulse. In the present work,
electrodeposition of Ni-Co/Cu multilayers has been studied to clarify if the
same optimization method is appropriate when two magnetic elements are present
and if this potential results in the largest giant magnetoresistance (GMR) for
the particular alloy system studied. For this purpose, several Ni-Co/Cu
multilayers were prepared by varying the deposition potential of the Cu layer.
The composition analysis of the deposits showed that the Ni:Co ratio exhibits a
minimum as a function of the Cu deposition potential, which can be explained by
considering both the dissolution of Co and the mass transport of the reactants.
Both the saturation GMR value and the intensity of the satellite peaks in the
X-ray diffractograms were highly correlated with the resulting surface
roughness of the deposits which was strongly varying with the Cu deposition
potential. Higher GMR values, lower saturation fields and more perfect
multilayer structure were observed for sufficiently positive Cu deposition
potentials only which enabled a partial Co dissolution resulting in a reduced
surface roughness. The results draw attention to the complexity of the
optimization procedure of the deposition of multilayers with several alloying
components.


title:
Scaling of compressible magnetohydrodynamic turbulence in the fast solar
  wind

abstract:
  The role of compressible fluctuations in the energy cascade of fast solar
wind turbulence is studied using a reduced form of an exact law derived
recently (Banerjee and Galtier, PRE, 2013) for compressible isothermal
magnetohydrodynamics and in-situ observations from the THEMIS B/ARTEMIS P1
spacecraft. A statistical survey of the data revealed a turbulent energy
cascade over two decades of scales, which is broader than the previous
estimates made from an exact incompressible law. A term-by-term analysis of the
compressible model reveals new insight into the role played by the compressible
fluctuations in the energy cascade. The compressible fluctuations are shown to
amplify (2 to 4 times) the turbulent cascade rate with respect to the
incompressible model in 10 % of the analyzed samples. This new estimated
cascade rate is shown to provide the adequate energy dissipation required.


title: Optimal Execution in a Multiplayer Model of Transient Price Impact

abstract:
  Trading algorithms that execute large orders are susceptible to exploitation
by order anticipation strategies. This paper studies the influence of order
anticipation strategies in a multi-investor model of optimal execution under
transient price impact. Existence and uniqueness of a Nash equilibrium is
established under the assumption that trading incurs quadratic transaction
costs. A closed-form representation of the Nash equilibrium is derived for
exponential decay kernels. With this representation, it is shown that while
order anticipation strategies raise the execution costs of a large order
significantly, they typically do not cause price overshooting in the sense of
Brunnermeier and Pedersen.


title: The supernova remnant W49B as seen with H.E.S.S. and Fermi-LAT

abstract:
  The supernova remnant (SNR) W49B originated from a core-collapse supernova
that occurred between one and four thousand years ago, and subsequently evolved
into a mixed-morphology remnant, which is interacting with molecular clouds
(MC). $\gamma$-ray observations of SNR/MC associations are a powerful tool to
constrain the origin of Galactic cosmic-rays, as they can probe the
acceleration of hadrons through their interaction with the surrounding medium
and subsequent emission of non-thermal photons. The detection of a $\gamma$-ray
source coincident with W49B at very high energies (VHE; E > 100 GeV) with the
H.E.S.S. Cherenkov telescopes is reported together with a study of the source
with 5 years of Fermi-LAT high energy $\gamma$-ray (0.06 - 300 GeV) data. The
smoothly-connected combined source spectrum, measured from 60 MeV to multi-TeV
energies, shows two significant spectral breaks at $304\pm20$ MeV and
$8.4_{-2.5}^{+2.2}$ GeV, the latter being constrained by the joint fit from the
two instruments. The detected spectral features are similar to those observed
in several other SNR/MC associations and are found to be indicative of
$\gamma$-ray emission produced through neutral-pion decay.


title: A Revised Gyro-Age for M 67 from Kepler/K2-Campaign-5 Light Curves

abstract:
  We revisit the photometric variability of stars in the M 67 field using
Kepler/K2-Campaign-5 light curves. In our previous work, we limited the search
area around M\,67 to that of a recent ground-based study. In the present work,
we expand the search area and apply a more rigorous period-finding algorithm to
determine the rotation periods of 98 main sequence cluster members from the
same data. In addition, we derive periods of 40 stars from the K2SC detrended
light curves. We determine the mean period of single sun-like main sequence
cluster members to be $29.6 \pm 0.6$ d. Assuming the periods correspond to
stellar rotation, the corresponding mean gyro-age is $5.4 \pm 0.2$ Gyr.


title: Climate Cycling on Early Mars Caused by the Carbonate-Silicate Cycle

abstract:
  For decades, scientists have tried to explain the evidence for fluvial
activity on early Mars, but a consensus has yet to emerge regarding the
mechanism for producing it. One hypothesis suggests early Mars was warmed by a
thick greenhouse atmosphere. Another suggests that early Mars was generally
cold but was warmed occasionally by impacts or by episodes of enhanced
volcanism. These latter hypotheses struggle to produce the amounts of rainfall
needed to form the martian valleys, but are consistent with inferred low rates
of weathering compared to Earth. Here, we provide a geophysical mechanism that
could have induced cycles of glaciation and deglaciation on early Mars. Our
model produces dramatic climate cycles with extended periods of glaciation
punctuated by warm periods lasting up to 10 Myr, much longer than those
generated in other episodic warming models. The cycles occur because stellar
insolation was low, and because CO2 outgassing is not able to keep pace with
CO2 consumption by silicate weathering followed by deposition of carbonates.
While CO2 by itself is not able to deglaciate early Mars in our model, we
assume that the greenhouse effect is enhanced by substantial amounts of H2
outgassed from Mars' reduced crust and mantle. Our hypothesis can be tested by
future Mars exploration that better establishes the time scale for valley
formation.


title:
Theoretical prediction of Reynolds stresses and velocity profiles for
  barotropic turbulent jets

abstract:
  It is extremely uncommon to be able to predict the velocity profile of a
turbulent flow. In two-dimensional flows, atmosphere dynamics, and plasma
physics, large scale coherent jets are created through inverse energy transfers
from small scales to the largest scales of the flow. We prove that in the
limits of vanishing energy injection, vanishing friction, and small scale
forcing, the velocity profile of a jet obeys an equation independent of the
details of the forcing. We find another general relation for the maximal
curvature of a jet and we give strong arguments to support the existence of an
hydrodynamic instability at the point with minimal jet velocity. Those results
are the first computations of Reynolds stresses and self consistent velocity
profiles from the turbulent dynamics, and the first consistent analytic theory
of zonal jets in barotropic turbulence.


title: Deformations of Wreath Products

abstract:
  Connectivity is a homotopy invariant property of a separable C*-algebra A
which has three important consequences: absence of nontrivial projections,
quasidiagonality and realization of the Kasparov group KK(A,B) as homotopy
classes of asymptotic morphisms from A to the stabilization of B if A is
nuclear. Here we give a new characterization of connectivity for separable
exact C*-algebras and use this characterization to show that the class of
discrete countable amenable groups whose augmentation ideals are connective is
closed under generalized wreath products. In a related circle of ideas, we give
a result on quasidiagonality of reduced crossed-product C*-algebras associated
to noncommutative Bernoulli actions.


title:
Attracting Currents and Equilibrium Measures for Quasi-attractors of
  $\mathbb P^k$

abstract:
  Let $f$ be a holomorphic endomorphism of $\mathbb P^k$ of degree $d.$ For
each quasi-attractor of $f$ we construct a finite set of currents with
attractive behaviors. To every such an attracting current is associated an
equilibrium measure which allows for a systematic ergodic theoretical approach
in the study of quasi-attractors of $\mathbb P^k.$ As a consequence, we deduce
that there exist at most countably many quasi-attractors, each one with
topological entropy equal to a multiple of $\log d.$ We also show that the
study of these analytic objects can initiate a bifurcation theory for
attracting sets.


title: The magnitude and direction of collider bias for binary variables

abstract:
  Suppose we are interested in the effect of variable $X$ on variable $Y$. If
$X$ and $Y$ both influence, or are associated with variables that influence, a
common outcome, called a collider, then conditioning on the collider (or on a
variable influenced by the collider -- its "child") induces a spurious
association between $X$ and $Y$, which is known as collider bias.
Characterizing the magnitude and direction of collider bias is crucial for
understanding the implications of selection bias and for adjudicating decisions
about whether to control for variables that are known to be associated with
both exposure and outcome but could be either confounders or colliders.
Considering a class of situations where all variables are binary, and where $X$
and $Y$ either are, or are respectively influenced by, two marginally
independent causes of a collider, we derive collider bias that results from (i)
conditioning on specific levels of, or (ii) linear regression adjustment for,
the collider (or its child). We also derive simple conditions that determine
the sign of such bias.


title:
Parton Shower Uncertainties in Jet Substructure Analyses with Deep
  Neural Networks

abstract:
  Machine learning methods incorporating deep neural networks have been the
subject of recent proposals for new hadronic resonance taggers. These methods
require training on a dataset produced by an event generator where the true
class labels are known. However, training a network on a specific event
generator may bias the network towards learning features associated with the
approximations to QCD used in that generator which are not present in real
data. We therefore investigate the effects of variations in the modelling of
the parton shower on the performance of deep neural network taggers using jet
images from hadronic W-bosons at the LHC, including detector-related effects.
By investigating network performance on samples from the Pythia, Herwig and
Sherpa generators, we find differences of up to fifty percent in background
rejection for fixed signal efficiency. We also introduce and study a method,
which we dub zooming, for implementing scale-invariance in neural network-based
taggers. We find that this leads to an improvement in performance across a wide
range of jet transverse momenta. Our results emphasise the importance gaining a
detailed understanding what aspects of jet physics these methods are
exploiting.


title:
On the spectral properties of Dirac operators with electrostatic
  $\delta$-shell interactions

abstract:
  In this paper the spectral properties of Dirac operators $A_\eta$ with
electrostatic $\delta$-shell interactions of constant strength $\eta$ supported
on compact smooth surfaces in $\mathbb{R}^3$ are studied. Making use of
boundary triple techniques a Krein type resolvent formula and a
Birman-Schwinger principle are obtained. With the help of these tools some
spectral, scattering, and asymptotic properties of $A_\eta$ are investigated.
In particular, it turns out that the discrete spectrum of $A_\eta$ inside the
gap of the essential spectrum is finite, the difference of the third powers of
the resolvents of $A_\eta$ and the free Dirac operator $A_0$ is trace class,
and in the nonrelativistic limit $A_\eta$ converges in the norm resolvent sense
to a Schr\"odinger operator with an electric $\delta$-potential of strength
$\eta$.


title:
Parton distribution of nucleon and nuclear EMC effect in a statistical
  model

abstract:
  We study the parton distribution of nucleon and nuclear EMC effect in a
statistical model. We find when we choose the parameters appropriately, the
predictions given by pure statistical laws can fit the experimental data well
in most range of $x$, this reveal statistical law play an important role in the
parton distribution of nucleon.


title: Modeling, refining and analyzing Incomplete B\"uchi Automata

abstract:
  Software development is an iterative process which includes a set of
development steps that transform the initial high level specification of the
system into its final, fully specified, implementation. This report discusses
the theoretical foundations that allow Incomplete B\"uchi Automata (IBAs) to be
used in the iterative development of a sequential system.


title:
On the Dispersion Relation of Magnetoplasmons in a Planar Graphene-Based
  Superlattice

abstract:
  The dispersion relation for magnetoplasmons in a planar superlattice with
periodically alternating regions of gapless and gapped modications of graphene
has been derived within the frame of the random-phase approximation. The
contribution of virtual transitions between the lower electron miniband and the
upper hole miniband to the polarization operator has been taken into account in
addition to the contribution of virtual intra-miniband transitions.


title:
Potential Energy Driven Spin Manipulation via a Controllable Hydrogen
  Ligand

abstract:
  Spin-bearing molecules can be stabilized on surfaces and in junctions with
desirable properties such as a net spin that can be adjusted by external
stimuli. Using scanning probes, initial and final spin states can be deduced
from topographic or spectroscopic data, but how the system transitioned between
these states is largely unknown. Here we address this question by manipulating
the total spin of magnetic cobalt hydride complexes on a corrugated boron
nitride surface with a hydrogen- functionalized scanning probe tip by
simultaneously tracking force and conductance. When the additional hydrogen
ligand is brought close to the cobalt monohydride, switching between a corre-
lated S = 1 /2 Kondo state, where host electrons screen the magnetic moment,
and a S = 1 state with magnetocrystalline anisotropy is observed. We show that
the total spin changes when the system is transferred onto a new potential
energy surface defined by the position of the hydrogen in the junction. These
results show how and why chemically functionalized tips are an effective tool
to manipulate adatoms and molecules, and a promising new method to selectively
tune spin systems.


title:
Analysis of the charmed mesons $D_{1}^{*}(2680)$, $D_{3}^{*}(2760)$ and
  $D_{2}^{*}(3000)$

abstract:
  In this work, we systematically study the strong decay behaviors of the
charmed mesons $D_{1}^{*}(2680)$, $D_{3}^{*}(2760)$ and $D_{2}^{*}(3000)$
reported by the LHCb collaboration. By comparing the masses and the decay
properties with the results of the experiment, we assigned these newly observed
mesons as the $2S\frac{1}{2}1^{-}$, $1D\frac{5}{2}3^{-}$ and
$1F\frac{5}{2}2^{+}$ states respectively. As a byproduct, we also study the
strong decays of the unobserved $2P\frac{3}{2}2^{+}$ and $2F\frac{5}{2}2^{+}$
charmed mesons, which is helpful to the future experiments in searching for
these charmed mesons.


title:
Can we Falsify the Consciousness-Causes-Collapse Hypothesis in Quantum
  Mechanics?

abstract:
  In this paper we examine some proposals to disprove the hypothesis that the
interaction between mind and matter causes the collapse of the wave function,
showing that such proposals are fundamentally flawed. We then describe a
general experimental setup retaining the key features of the ones examined, and
show that even a more general case is inadequate to disprove the mind-matter
collapse hypothesis. Finally, we use our setup provided to argue that, under
some reasonable assumptions about consciousness, such hypothesis is
unfalsifiable.


title:
Artificial gravity field, astrophysical analogues, and topological phase
  transitions in strained topological semimetals

abstract:
  Effective gravity and gauge fields are emergent properties intrinsic for
low-energy quasiparticles in topological semimetals. Here, taking two Dirac
semimetals as examples, we demonstrate that applied lattice strain can generate
warped spacetime, with fascinating analogues in astrophysics. Particularly, we
study the possibility of simulating black-hole/white-hole event horizons and
gravitational lensing effect. Furthermore, we discover strain-induced
topological phase transitions, both in the bulk materials and in their thin
films. Especially in thin films, the transition between the quantum spin Hall
and the trivial insulating phases can be achieved by a small strain, naturally
leading to the proposition of a novel piezo-topological transistor device.
Possible experimental realizations and analogue of Hawking radiation effect are
discussed. Our result bridges multiple disciplines, revealing topological
semimetals as a unique table-top platform for exploring interesting phenomena
in astrophysics and general relativity; it also suggests realistic materials
and methods to achieve controlled topological phase transitions with great
potential for device applications.


title: SHA-1 and the Strict Avalanche Criterion

abstract:
  The Strict Avalanche Criterion (SAC) is a measure of both confusion and
diffusion, which are key properties of a cryptographic hash function. This work
provides a working definition of the SAC, describes an experimental methodology
that can be used to statistically evaluate whether a cryptographic hash meets
the SAC, and uses this to investigate the degree to which compression function
of the SHA-1 hash meets the SAC. The results ($P < 0.01$) are heartening: SHA-1
closely tracks the SAC after the first 24 rounds, and demonstrates excellent
properties of confusion and diffusion throughout.


title:
Orientation-Preservation Conditions on an Iso-parametric FEM in
  Cavitation Computation

abstract:
  The orientation-preservation condition, i.e., the Jacobian determinant of the
deformation gradient $\det \nabla u$ is required to be positive, is a natural
physical constraint in elasticity as well as in many other fields. It is well
known that the constraint can often cause serious difficulties in both
theoretical analysis and numerical computation, especially when the material is
subject to large deformations. In this paper, we derive a set of sufficient and
necessary conditions for the quadratic iso-parametric finite element
interpolation functions of cavity solutions to be orientation preserving on a
class of radially symmetric large expansion accommodating triangulations. The
result provides a practical quantitative guide for meshing in the neighborhood
of a cavity and shows that the orientation-preservation can be achieved with a
reasonable number of total degrees of freedom by the quadratic iso-parametric
finite element method.


title: The feedback effect caused by bed load on a turbulent liquid flow

abstract:
  Experiments on the effects due solely to a mobile granular layer on a liquid
flow are presented (feedback effect). Nonintrusive measurements were performed
in a closed conduit channel of rectangular cross section where grains were
transported as bed load by a turbulent water flow. The water velocity profiles
were measured over fixed and mobile granular beds of same granulometry by
Particle Image Velocimetry. The spatial resolution of the measurements allowed
the experimental quantification of the feedback effect. The present findings
are of importance for predicting the bed-load transport rate and the pressure
drop in activities related to the conveyance of grains.


title:
Charge neutrality breakdown in confined aqueous electrolytes: theory and
  simulation

abstract:
  We study, using Density Functional theory and Monte Carlo simulations,
aqueous electrolyte solutions between charged infinite planar surfaces, in a
contact with a bulk salt reservoir. In agreement with recent experimental
observations [Z. Luo et al., Nat. Comm. 6, 6358 (2015)], we find that the
confined electrolyte lacks local charge neutrality. We show that a Density
Functional Theory (DFT) based on a bulk- HNC expansion properly accounts for
strong electrostatic correlations and allows us to accurately calculate the
ionic density profiles between the charged surfaces, even for electrolytes
containing trivalent counterions. The DFT allows us to explore the degree of
local charge neutrality violation, as a function of plate separation and bulk
electrolyte concentration, and to accurately calculate the interaction force
between the charged surfaces.


title: Bone Remodeling as a Spatial Evolutionary Game

abstract:
  Bone remodeling is a complex process involving cell-cell interactions,
biochemical signaling and mechanical stimuli. Early models of the biological
aspects of remodeling were non-spatial and focused on the local dynamics at a
fixed location in the bone. Several spatial extensions of these models have
been proposed, but they generally suffer from two limitations: first, they are
not amenable to analysis and are computationally expensive, and second, they
neglect the role played by bone-embedded osteocytes. To address these issues,
we developed a novel model of spatial remodeling based on the principles of
evolutionary game theory. The analytically tractable framework describes the
spatial interactions between zones of bone resorption, bone formation and
quiescent bone, and explicitly accounts for regulation of remodeling by
bone-embedded, mechanotransducing osteocytes. Using tools from the theory of
interacting particle systems we systematically classified the different dynamic
regimes of the spatial model and identified regions of parameter space that
allow for coexistence of resorption, formation and quiescence, as observed in
physiological remodeling. In coexistence scenarios, three-dimensional
simulations revealed the emergence of sponge-like bone clusters. Comparison
between spatial and non-spatial dynamics revealed substantial differences and
suggested a stabilizing role of space. Our findings emphasize the importance of
accounting for spatial structure and bone-embedded osteocytes when modeling the
process of bone remodeling. Thanks to the lattice-based framework, the proposed
model can easily be coupled to a mechanical model of bone loading.


title:
Device-to-device Cooperation in Massive MIMO Systems with Cascaded
  Precoding

abstract:
  This paper investigates user cooperation in massive multiple-input
multiple-output (MIMO) systems with cascaded precoding. The high-dimensional
physical channel in massive MIMO systems can be converted into a
low-dimensional effective channel through the inner precoder to reduce the
overhead of channel estimation and feedback. The inner precoder depends on the
spatial covariance matrix of the channels, and thus the same precoder can be
used for different users as long as they have the same spatial covariance
matrix. Spatial covariance matrix is determined by the surrounding environment
of user terminals. Therefore, the users that are close to each other will share
the same spatial covariance matrix. In this situation, it is possible to
achieve user cooperation by sharing receiver information through some dedicated
link, such as device-to-device communications. To reduce the amount of
information that needs to be shared, we propose a decoding codebook based
scheme, which can achieve user cooperation without the need of channel state
information. Moreover, we also investigate the amount of bandwidth required to
achieve efficient user cooperation. Simulation results show that user
cooperation can improve the capacity compared to the non-cooperation scheme.


title: Dissipative entanglement of solid-state spins in diamond

abstract:
  Generating robust entanglement among solid-state spins is key for
applications in quantum information processing and precision sensing. We show
here a dissipative approach to generate such entanglement among the hyperfine
coupled electron nuclear spins using the rapid optical decay of electronic
excited states. The combined dark state interference effects of the optical and
microwave driving fields in the presence of spontaneous emission from the
short-lived excited state leads to a dissipative formation of an entangled
steady state. We show that the dissipative entanglement is generated for any
initial state conditions of the spins and is resilient to external field
fluctuations. We analyze the scheme both for continuous and pulsed driving
fields in the presence of realistic noise sources.


title: The double-layer structure of overscreened surfaces by smeared-out ions

abstract:
  Charge inversion occurring for smeared-out ions is accompanied by an
oscillatory charge density profile, indicating a layering of an alternating
charge. The layering effect, however, is not coextensive with charge inversion,
and charge inversion accompanied by a monotonically decaying profile is
possible. The present work focuses on the structure of a double-layer of
overscreened charged surfaces by smeared-out charges and probes the link
between the structure of a double-layer and the bulk properties of an
electrolyte, with special view to the role of the Kirkwood crossover.


title: Intrinsic mirror symmetry and punctured Gromov-Witten invariants

abstract:
  This contribution to the 2015 AMS Summer Institute in Algebraic Geometry
(Salt Lake City) announces a general mirror construction. This construction
applies to log Calabi-Yau pairs (X,D) with maximal boundary D or to maximally
unipotent degenerations of Calabi-Yau manifolds. The new ingredient is a notion
of "punctured Gromov-Witten invariant", currently in progress with Abramovich
and Chen. The mirror to a pair (X,D) is constructed as the spectrum of a ring
defined using the punctured invariants of (X,D). An analogous construction
leads to mirrors of Calabi-Yau manifolds. This can be viewed as a
generalization of constructions developed jointly with Hacking and Keel in the
case of log CY surfaces and K3 surfaces.


title: Parahoric Restriction for GSp(4)

abstract:
  We determine the parahoric restriction of non-cuspidal irreducible smooth
representations of GSp(4,F) for a local non-archimedean number field F.


title: SynsetRank: Degree-adjusted Random Walk for Relation Identification

abstract:
  In relation extraction, a key process is to obtain good detectors that find
relevant sentences describing the target relation. To minimize the necessity of
labeled data for refining detectors, previous work successfully made use of
BabelNet, a semantic graph structure expressing relationships between synsets,
as side information or prior knowledge. The goal of this paper is to enhance
the use of graph structure in the framework of random walk with a few
adjustable parameters. Actually, a straightforward application of random walk
degrades the performance even after parameter optimization. With the insight
from this unsuccessful trial, we propose SynsetRank, which adjusts the initial
probability so that high degree nodes influence the neighbors as strong as low
degree nodes. In our experiment on 13 relations in the FB15K-237 dataset,
SynsetRank significantly outperforms baselines and the plain random walk
approach.


title:
Smart Computing and Sensing Technologies for Animal Welfare: A
  Systematic Review

abstract:
  Animals play a profoundly important and intricate role in our lives today.
Dogs have been human companions for thousands of years, but they now work
closely with us to assist the disabled, and in combat and search and rescue
situations. Farm animals are a critical part of the global food supply chain,
and there is increasing consumer interest in organically fed and humanely
raised livestock, and how it impacts our health and environmental footprint.
Wild animals are threatened with extinction by human induced factors, and
shrinking and compromised habitat. This review sets the goal to systematically
survey the existing literature in smart computing and sensing technologies for
domestic, farm and wild animal welfare. We use the notion of \emph{animal
welfare} in broad terms, to review the technologies for assessing whether
animals are healthy, free of pain and suffering, and also positively stimulated
in their environment. Also the notion of \emph{smart computing and sensing} is
used in broad terms, to refer to computing and sensing systems that are not
isolated but interconnected with communication networks, and capable of remote
data collection, processing, exchange and analysis. We review smart
technologies for domestic animals, indoor and outdoor animal farming, as well
as animals in the wild and zoos. The findings of this review are expected to
motivate future research and contribute to data, information and communication
management as well as policy for animal welfare.


title:
Quasi-phase-matched high harmonic generation in corrugated
  micrometer-scale waveguides

abstract:
  The high harmonic generation in periodically corrugated submicrometer
waveguides is studied numerically. Plasmonic field enhancement in the vicinity
of the corrugations allows to use low pump intensities. Simultaneously,
periodic placement of the corrugations leads to quasi-phase-matching and
corresponding increase of the high harmonic efficiency. The optimization of
waveguide geometry is performed, and the resulting spectra are analyzed by the
means of (1+1)D numerical model.


title:
SEBOOST - Boosting Stochastic Learning Using Subspace Optimization
  Techniques

abstract:
  We present SEBOOST, a technique for boosting the performance of existing
stochastic optimization methods. SEBOOST applies a secondary optimization
process in the subspace spanned by the last steps and descent directions. The
method was inspired by the SESOP optimization method for large-scale problems,
and has been adapted for the stochastic learning framework. It can be applied
on top of any existing optimization method with no need to tweak the internal
algorithm. We show that the method is able to boost the performance of
different algorithms, and make them more robust to changes in their
hyper-parameters. As the boosting steps of SEBOOST are applied between large
sets of descent steps, the additional subspace optimization hardly increases
the overall computational burden. We introduce two hyper-parameters that
control the balance between the baseline method and the secondary optimization
process. The method was evaluated on several deep learning tasks, demonstrating
promising results.


title:
Nanosecond-level time synchronization of AERA using a beacon reference
  transmitter and commercial airplanes

abstract:
  Radio detection of cosmic-ray air showers requires time synchronization of
detectors on a nanosecond level, especially for advanced reconstruction
algorithms based on the wavefront curvature and for interferometric analysis
approaches. At the Auger Engineering Radio Array, the distributed, autonomous
detector stations are time-synchronized via the Global Positioning System
which, however, does not provide sufficient timing accuracy. We thus employ a
dedicated beacon reference transmitter to correct for event-by-event clock
drifts in our offline data analysis. In an independent cross-check of this
"beacon correction" using radio pulses emitted by commercial airplanes, we have
shown that the combined timing accuracy of the two methods is better than 2
nanoseconds.