title: Speaker Recognition for Children's Speech

abstract:
  This paper presents results on Speaker Recognition (SR) for children's
speech, using the OGI Kids corpus and GMM-UBM and GMM-SVM SR systems. Regions
of the spectrum containing important speaker information for children are
identified by conducting SR experiments over 21 frequency bands. As for adults,
the spectrum can be split into four regions, with the first (containing primary
vocal tract resonance information) and third (corresponding to high frequency
speech sounds) being most useful for SR. However, the frequencies at which
these regions occur are from 11% to 38% higher for children. It is also noted
that subband SR rates are lower for younger children. Finally results are
presented of SR experiments to identify a child in a class (30 children,
similar age) and school (288 children, varying ages). Class performance depends
on age, with accuracy varying from 90% for young children to 99% for older
children. The identification rate achieved for a child in a school is 81%.


title:
Statistical Analysis of Binary Functional Graphs of the Discrete
  Logarithm

abstract:
  The increased use of cryptography to protect our personal information makes
us want to understand the security of cryptosystems. The security of many
cryptosystems relies on solving the discrete logarithm, which is thought to be
relatively difficult. Therefore, we focus on the statistical analysis of
certain properties of the graph of the discrete logarithm. We discovered the
expected value and variance of a certain property of the graph and compared the
expected value to experimental data. Our finding did not coincide with our
intuition of the data following a Gaussian distribution given a large sample
size. Thus, we found the theoretical asymptotic distributions of certain
properties of the graph.


title: Colors of Ellipticals from GALEX to Spitzer

abstract:
  Multi-color photometry is presented for a large sample of local ellipticals
selected by morphology and isolation. The sample uses data from GALEX, SDSS,
2MASS and Spitzer to cover the filters NUV, ugri, JHK and 3.6mum. Various
two-color diagrams, using the half-light aperture defined in the 2MASS J
filter, are very coherent from color to color, meaning that galaxies defined to
be red in one color are always red in other colors. Comparison to globular
cluster colors demonstrates that ellipticals are *not* composed of a single
age, single metallicity (e.g., [Fe/H]) stellar population, but require a
multi-metallicity model using a chemical enrichment scenario. Such a model is
sufficient to explain two-color diagrams and the color-magnitude relations for
all colors using only metallicity as a variable on a solely 12 Gyrs stellar
population with no evidence of stars younger than 10 Gyrs. The [Fe/H] values
that match galaxy colors range from -0.5 to +0.4, much higher (and older) than
population characteristics deduced from Lick/IDS line-strength system studies,
indicating an inconsistency between galaxy colors and line indices values for
reasons unknown. The NUV colors have unusual behavior signaling the rise and
fall of the UV upturn with elliptical luminosity. Models with BHB tracks can
reproduce this behavior indicating the UV upturn is strictly a metallicity
effect.


title:
Safety Certified Cooperative Adaptive Cruise Control under Unreliable
  Inter-vehicle Communications

abstract:
  Cooperative adaptive cruise control(CACC) system provides a great promise to
significantly reduce traffic congestion while maintaining a high level of
safety. Recent years have seen an increase of using formal methods in the
analysis and design of cooperative adaptive cruise control systems. However,
most existing results using formal methods usually assumed an ideal
inter-vehicle communication, which is far from the real world situation. Hence,
we are motivated to close the gap by explicitly considering non-deterministic
time delay and packet dropout due to unreliable inter-vehicle communications.
In particular, we consider a passive safety property, which requests a vehicle
to avoid any collisions that can be considered as its fault. Under the
assumption that the communication delay is bounded and we know the upper bound,
we then formally verify the passivity safety of a class of hybrid CACC systems.
This result allows us to define a safe control envelope that will guide the
synthesis of control signals. Vehicles under the CACC within the safe control
envelope are guaranteed to avoid active collisions.


title:
Nodal Line Entanglement Entropy: Generalized Widom Formula from
  Entanglement Hamiltonians

abstract:
  A system of fermions forming a Fermi surface exhibits a large degree of
quantum entanglement, even in the absence of interactions. In particular, the
usual case of a codimension one Fermi surface leads to a logarithmic violation
of the area law for entanglement entropy, as dictated by the Widom formula. We
here generalize this formula to the case of arbitrary codimension, which is of
particular interest for nodal lines in three dimensions. We first rederive the
standard Widom formula by calculating an entanglement Hamiltonian for Fermi
surface systems, obtained by repurposing a trick commonly applied to
relativistic theories. The entanglement Hamiltonian will take a local form in
terms of a low-energy patch theory for the Fermi surface, though it is nonlocal
with respect to the microscopic fermions. This entanglement Hamiltonian can
then be used to derive the entanglement entropy, yielding a result in agreement
with the Widom formula. The method is then generalized to arbitrary
codimension. For nodal lines, the area law is obeyed, and the magnitude of the
coefficient for a particular partition is non-universal. However, the
coefficient has a universal dependence on the shape and orientation of the
nodal line relative to the partitioning surface. By comparing the relative
magnitude of the area law for different partitioning cuts, entanglement entropy
can be used as a tool for diagnosing the presence and shape of a nodal line in
a ground state wavefunction.


title: Dawes Review. The tidal downsizing hypothesis of planet formation

abstract:
  Tidal Downsizing is the modern version of the Kuiper (1951) scenario of
planet formation. Detailed simulations of self-gravitating discs, gas
fragments, dust grain dynamics, and planet evolutionary calculations are
summarised here and used to build a predictive planet formation model and
population synthesis. A new interpretation of exoplanetary and debris disc
data, the Solar System's origins, and the links between planets and brown
dwarfs is offered. This interpretation is contrasted with the current
observations and the predictions of the Core Accretion theory. Observations
that can distinguish the two scenarios are pointed out. In particular, Tidal
Downsizing predicts that presence of debris discs, sub-Neptune mass planets,
planets more massive than $\sim 5$~Jupiter masses and brown dwarfs should not
correlate strongly with the metallicity of the host. For gas giants of $\sim$
Saturn to a few Jupiter mass, a strong host star metallicity correlation is
predicted only inwards of a few AU from the host. Composition of massive cores
is predicted to be dominated by rock rather than ices. Debris discs made by
Tidal Downsizing are distinct from those made by Core Accretion at birth: they
have an innermost edge always larger than about 1 au, have smaller total masses
and are usually in a dynamically excited state. It is argued that planet
formation in surprisingly young or very dynamic systems such as HL Tau and
Kepler-444 may be a signature of Tidal Downsizing. Open questions and potential
weaknesses of the hypothesis are pointed out.


title:
Transport and localization in a topological phononic lattice with
  correlated disorder

abstract:
  Recently proposed classical analogs of topological insulators in phononic
lattices have the advantage of much more accessible experimental realization as
compared to conventional materials. Drawn to their potential practical
structural applications, we investigate how disorder, which is generically
non-negligible in macroscopic realization, can attenuate the topologically
protected edge (TPE) modes that constitute robust transmitting channels at zero
disorder. We simulate the transmission of phonon modes in a
quasi-one-dimensional classical lattice waveguide with mass disorder, and show
that the TPE mode transmission remains highly robust ($\Xi\sim1$) in the
presence of uncorrelated disorder, but diminishes when disorder is spatially
correlated. This reduction in transmittance is attributed to the Anderson
localization of states within the mass disorder domains. By contrast, non-TPE
channels exhibit qualitatively different behavior, with spatial correlation in
the mass disorder leading to significant transmittance reduction (enhancement)
at low (high) frequencies. Our results demonstrate how topologically protected
edge modes drastically modify the effect of spatial correlation on mode
localization.


title:
Conic Programming Reformulations of Two-Stage Distributionally Robust
  Linear Programs over Wasserstein Balls

abstract:
  Adaptive robust optimization problems are usually solved approximately by
restricting the adaptive decisions to simple parametric decision rules.
However, the corresponding approximation error can be substantial. In this
paper we show that two-stage robust and distributionally robust linear programs
can often be reformulated exactly as conic programs that scale polynomially
with the problem dimensions. Specifically, when the ambiguity set constitutes a
2-Wasserstein ball centered at a discrete distribution, then the
distributionally robust linear program is equivalent to a copositive program
(if the problem has complete recourse) or can be approximated arbitrarily
closely by a sequence of copositive programs (if the problem has sufficiently
expensive recourse). These results directly extend to the classical robust
setting and motivate strong tractable approximations of two-stage problems
based on semidefinite approximations of the copositive cone. We also
demonstrate that the two-stage distributionally robust optimization problem is
equivalent to a tractable linear program when the ambiguity set constitutes a
1-Wasserstein ball centered at a discrete distribution and there are no support
constraints.


title: On the local equivalence of partial differential equations

abstract:
  In all the practical applications of partial differential equations, what is
mostly needed and what is in fact hardest to obtains are the solutions of the
system or, occasionally, some specific solutions. This work is based on a most
enlightening M\'emoire written by \'Elie Cartan in 1914 and that the majority
ignores. We discuss a setting for the local equivalence problem and illustrate
it by some examples. It should also be noted that any integration process or
method is in fact a local equivalence problem involving a suitable model.


title:
Construction of Perturbatively Correct Light Front Hamiltonian for
  (2+1)-Dimensional Gauge Theory

abstract:
  In this paper we consider (2+1)-dimensional SU(N)-symmetric gauge theory
within light front perturbation theory, regularized by the method analogous to
Pauli-Villars regularization. This enables us to construct correct renormalized
light front Hamiltonian.


title: Observation of genuine three-photon interference

abstract:
  Multiparticle quantum interference is critical for our understanding and
exploitation of quantum information, and for fundamental tests of quantum
mechanics. A remarkable example of multi-partite correlations is exhibited by
the Greenberger-Horne-Zeilinger (GHZ) state. In a GHZ state, three particles
are correlated while no pairwise correlation is found. The manifestation of
these strong correlations in an interferometric setting has been studied
theoretically since 1990 but no three-photon GHZ interferometer has been
realized experimentally. Here we demonstrate three-photon interference that
does not originate from two-photon or single photon interference. We observe
phase-dependent variation of three-photon coincidences with 90.5 \pm 5.0 %
visibility in a generalized Franson interferometer using energy-time entangled
photon triplets. The demonstration of these strong correlations in an
interferometric setting provides new avenues for multiphoton interferometry,
fundamental tests of quantum mechanics and quantum information applications in
higher dimensions.


title: Proof mining and effective bounds in differential polynomial rings

abstract:
  Using the functional interpretation from proof theory, we analyze
nonconstructive proofs of several central theorems about polynomial and
differential polynomial rings. We extract effective bounds, some of which are
new to the literature, from the resulting proofs. In the process we discuss the
constructive content of Noetherian rings and the Nullstellensatz in both the
classical and differential settings. Sufficient background is given to
understand the proof-theoretic and differential-algebraic framework of the main
results.


title: Wind-driven Accretion in Transitional Protostellar Disks

abstract:
  Transitional protostellar disks have inner cavities heavily depleted in dust
and gas, yet most show signs of ongoing accretion, often at rates comparable to
full disks. We show that recent constraints on the gas surface density in a few
well-studied disk cavities imply that the accretion speed is at least
transsonic. We propose that this is the natural result of accretion driven by
magnetized winds. Typical physical conditions of the gas inside such cavities
are estimated for plausible X-ray and FUV radiation fields. The gas is
molecular and predominantly neutral, with a dimensionless ambipolar parameter
in the right general range for wind solutions of the type developed by
K\"onigl, Wardle, and others. That is to say, the density of ions and electrons
is sufficient for moderately good coupling to the magnetic field, but not so
good that the magnetic flux need be dragged inward by the accreting neutrals.


title:
Mortality and life expectancy forecasting for a group of populations in
  developed countries: A robust multilevel functional data method

abstract:
  A robust multilevel functional data method is proposed to forecast
age-specific mortality rate and life expectancy for two or more populations in
developed countries with high-quality vital registration systems. It uses a
robust multilevel functional principal component analysis of aggregate and
population-specific data to extract the common trend and population-specific
residual trend among populations. This method is applied to age- and
sex-specific mortality rate and life expectancy for the United Kingdom from
1922 to 2011, and its forecast accuracy is then further compared with standard
multilevel functional data method. For forecasting both age-specific mortality
and life expectancy, the robust multilevel functional data method produces more
accurate point and interval forecasts than the standard multilevel functional
data method in the presence of outliers.


title:
Kinematics in the Galactic Bulge with APOGEE: II. High-Order Kinematical
  Moments and Comparison to Extragalactic Bar Diagnostics

abstract:
  Much of the inner Milky Way's (MW) global rotation and velocity dispersion
patterns can be reproduced by models of secularly-evolved, bar-dominated
bulges. More sophisticated constraints, including the higher moments of the
line-of-sight velocity distributions (LOSVDs) and limits on the chemodynamical
substructure, are critical for interpreting observations of the unresolved
inner regions of extragalactic systems and for placing the MW in context with
other galaxies. Here, we use SDSS-APOGEE data to develop these constraints, by
presenting the first maps of the LOSVD skewness and kurtosis of metal-rich and
metal-poor inner MW stars (divided at [Fe/H] = -0.4), and comparing the
observed patterns to those that are seen both in N-body models and in
extragalactic bars. Despite closely matching the mean velocity and dispersion,
the models do not reproduce the observed LOSVD skewness patterns in different
ways, which demonstrates that our understanding of the detailed orbital
structure of the inner MW remains an important regime for improvement. We find
evidence in the MW of the skewness-velocity correlation that is used as a
diagnostic of extragalactic bar/bulges. This correlation appears in metal-rich
stars only, providing further evidence for different evolutionary histories of
chemically differentiated populations. We connect these skewness measurements
to previous work on high-velocity "peaks" in the inner Galaxy, confirming the
presence of that phenomenon, and we quantify the cylindrical rotation of the
inner Galaxy, finding that the latitude-independent rotation vanishes outside
of lon ~ 7 deg. Finally, we evaluate the MW data in light of select
extragalactic bar diagnostics and discuss progress and challenges of using the
MW as a resolved analog of unresolved stellar populations.


title: X-ray Fourier ptychographic microscopy

abstract:
  Following the recent developement of Fourier ptychographic microscopy (FPM)
in the visible range by Zheng et al. (2013), we propose an adaptation for hard
x-rays. FPM employs ptychographic reconstruction to merge a series of
low-resolution, wide field of view images into a high-resolution image. In the
x-ray range this opens the possibility to overcome the limited numerical
aperture of existing x-ray lenses. Furthermore, digital wave front correction
(DWC) may be used to charaterize and correct lens imperfections. Given the
diffraction limit achievable with x-ray lenses (below 100 nm), x-ray Fourier
ptychographic microscopy (XFPM) should be able to reach resolutions in the 10
nm range.


title:
An integrated and multi-purpose microscope for the characterization of
  atomically thin optoelectronic devices

abstract:
  Optoelectronic devices based on graphene and other two-dimensional (2D)
materials, such as transition metal dichalcogenides (TMDs) are the focus of
wide research interest. The characterization these emerging atomically thin
materials and devices strongly relies on a set of measurements involving both
optical and electronic instrumentation ranging from scanning photocurrent
mapping to Raman and photoluminescence (PL) spectroscopy. Furthermore,
proof-of-concept devices are usually fabricated from micro-meter size flakes,
requiring microscopy techniques to characterize them. Current state-of-the-art
commercial instruments offer the ability to characterize individual properties
of these materials with no option for the in situ characterization of a wide
enough range of complementary optical and electrical properties. Presently, the
requirement to switch atomically-thin materials from one system to another
often radically affects the properties of these uniquely sensitive materials
through atmospheric contamination. Here, we present an integrated,
multi-purpose instrument dedicated to the optical and electrical
characterization of devices based on 2D materials which is able to perform low
frequency electrical measurements, scanning photocurrent mapping, Raman,
absorption and PL spectroscopy in one single set-up. We characterize this
apparatus by performing multiple measurements on graphene, transition metal
dichalcogenides (TMDs) and Si. The performance and resolution of each
individual measurement technique is found to be equivalent to that of
commercially available instruments. Contrary to nowadays commercial systems, a
significant advantage of the developed instrument is that for the first time
the integration of a wide range of complementary opto-electronic and
spectroscopy characterization techniques is demonstrated in a single compact
unit.

categories: physics.ins-det cond-mat.mtrl-sci cond-mat.other physics.app-ph physics.optics


title:
Low Background Stainless Steel for the Pressure Vessel in the PandaX-II
  Dark Matter Experiment

abstract:
  We report on the custom produced low radiation background stainless steel and
the welding rod for the PandaX experiment, one of the deep underground
experiments to search for dark matter and neutrinoless double beta decay using
xenon. The anthropogenic 60 Co concentration in these samples is at the range
of 1 mBq/kg or lower. We also discuss the radioactivity of nuclear-grade
stainless steel from TISCO which has a similar background rate. The PandaX-II
pressure vessel was thus fabricated using the stainless steel from CISRI and
TISCO. Based on the analysis of the radioactivity data, we also made
discussions on potential candidate for low background metal materials for
future pressure vessel development.


title: Topologically protected localised states in spin chains

abstract:
  We consider spin chain families inspired by the Su, Schrieffer and Hegger
(SSH) model. We demonstrate explicitly the topologically induced spatial
localisation of quantum states in our systems. We present detailed
investigations of the effects of random noise, showing that these topologically
protected states are very robust against this type of perturbation. Systems
with such topological robustness are clearly good candidates for quantum
information tasks and we discuss some potential applications. Thus, we present
interesting spin chain models which show promising applications for quantum
devices.


title:
SimBa: An Efficient Tool for Approximating Rips-filtration Persistence
  via Simplicial Batch-collapse

abstract:
  In topological data analysis, a point cloud data P extracted from a metric
space is often analyzed by computing the persistence diagram or barcodes of a
sequence of Rips complexes built on $P$ indexed by a scale parameter.
Unfortunately, even for input of moderate size, the size of the Rips complex
may become prohibitively large as the scale parameter increases. Starting with
the Sparse Rips filtration introduced by Sheehy, some existing methods aim to
reduce the size of the complex so as to improve the time efficiency as well.
However, as we demonstrate, existing approaches still fall short of scaling
well, especially for high dimensional data. In this paper, we investigate the
advantages and limitations of existing approaches. Based on insights gained
from the experiments, we propose an efficient new algorithm, called SimBa, for
approximating the persistent homology of Rips filtrations with quality
guarantees. Our new algorithm leverages a batch collapse strategy as well as a
new sparse Rips-like filtration. We experiment on a variety of low and high
dimensional data sets. We show that our strategy presents a significant size
reduction, and our algorithm for approximating Rips filtration persistence is
order of magnitude faster than existing methods in practice.


title:
QUARKS: Identification of large-scale Kronecker Vector-AutoRegressive
  models

abstract:
  In this paper we propose a Kronecker-based modeling for identifying the
spatial-temporal dynamics of large sensor arrays. The class of Kronecker
networks is defined for which we formulate a Vector Autoregressive model. Its
coefficient-matrices are decomposed into a sum of Kronecker products. For a
two-dimensional array of size $N \times N$, and when the number of terms in the
sum is small compared to $N$, exploiting the Kronecker structure leads to high
data compression. We propose an Alternating Least Squares algorithm to identify
the coefficient matrices with $\mathcal{O}(N^3N_t)$, where $N_t$ is the number
of temporal samples, instead of $\mathcal{O}(N^6)$ in the unstructured case.
This framework moreover allows for a convenient integration of more structure
(e.g sparse, banded, Toeplitz) on the factor matrices. Numerical examples on
atmospheric turbulence data has shown comparable performances with the
unstructured least-squares estimation while the number of parameters is growing
only linearly w.r.t. the number of nodes instead of quadratically in the full
unstructured matrix case.


title: On the strength of some topological lattices

abstract:
  We study the model theoretic strength of various lattices that occur
naturally in topology, like closed (semi-linear or semi-algebraic or convex)
sets. The method is based on weak monadic second order logic and sharpens
previous results by Grzegorczyk. We also answers a question of Grzegorczyk on
the 'algebra of convex sets'.


title: Applying Bayesian Inference to Galileon Solutions of the Muon Problem

abstract:
  We derive corrections to atomic energy levels from disformal couplings in
Galileon theories. Through Bayesian inference, we constrain the cutoff radii
and Galileon scale via these corrections. To connect different atomic systems,
we assume the various cutoff radii related by a one-parameter family of
solutions. This introduces a new parameter $\alpha$ which is also constrained.
In this model, we predict shifts to muonic helium of $\delta
E_{He^3}=1.97^{+9.28}_{-1.87}$ meV and $\delta E_{He^4}=1.69^{+9.25}_{-1.61}$
meV as well as for true muonium, $\delta E_{TM}=0.06^{+0.46}_{-0.05}$ meV.


title: Fast Learning of Clusters and Topics via Sparse Posteriors

abstract:
  Mixture models and topic models generate each observation from a single
cluster, but standard variational posteriors for each observation assign
positive probability to all possible clusters. This requires dense storage and
runtime costs that scale with the total number of clusters, even though
typically only a few clusters have significant posterior mass for any data
point. We propose a constrained family of sparse variational distributions that
allow at most $L$ non-zero entries, where the tunable threshold $L$ trades off
speed for accuracy. Previous sparse approximations have used hard assignments
($L=1$), but we find that moderate values of $L>1$ provide superior
performance. Our approach easily integrates with stochastic or incremental
optimization algorithms to scale to millions of examples. Experiments training
mixture models of image patches and topic models for news articles show that
our approach produces better-quality models in far less time than baseline
methods.


title: Interpreting formulas of divisible lattice ordered abelian groups

abstract:
  We show that a large class of divisible abelian $\ell$-groups (lattice
ordered groups) of continuous functions is interpretable (in a certain sense)
in the lattice of the zero sets of these functions. This has various
applications to the model theory of these $\ell$-groups, including decidability
results.


title:
Complexity of holomorphic maps from the complex unit ball to classical
  domains

abstract:
  We study the complexity of holomorphic isometries and proper maps from the
complex unit ball to type IV classical domains. We investigate on degree
estimates of holomorphic isometries and holomorphic maps with minimum target
dimension. We also construct a real-parameter family of mutually inequivalent
holomorphic isometries from the unit ball to type IV domains. We also provide
examples of non-isometric proper holomorphic maps from the complex unit ball to
classical domains.


title: Renormalization of unicritical analytic circle maps

abstract:
  In this paper we generalize renormalization theory for analytic critical
circle maps with a cubic critical point to the case of maps with an arbitrary
odd critical exponent by proving a quasiconformal rigidity statement for
renormalizations of such maps.


title: Boundary Measurement Matrices for Directed Networks on Surfaces

abstract:
  Franco, Galloni, Penante, and Wen have proposed a boundary measurement map
for a graph on any closed orientable surface with boundary. We consider this
boundary measurement map which takes as input an edge weighted directed graph
embedded on a surface and produces on element of a Grassmannian. Computing the
boundary measurement requires a choice of fundamental domain. Here the boundary
measurement map is shown to be independent of the choice of fundamental domain
Also, a formula for the Pl\"ucker coordinates of the element of Grassmannian in
the image of the boundary measurement map is given. The formula expresses the
Pl\"ucker coordinates as a rational function which can be combinatorially
described in terms of paths and cycles in the directed graph.


title: Balancing Speed and Coverage by Sequential Seeding in Complex Networks

abstract:
  Information spreading in complex networks is often modeled as diffusing
information with certain probability from nodes that possess it to their
neighbors that do not. Information cascades are triggered when the activation
of a set of initial nodes (seeds) results in diffusion to large number of
nodes. Here, several novel approaches for seed initiation that replace the
commonly used activation of all seeds at once with a sequence of initiation
stages are introduced. Sequential strategies at later stages avoid seeding
highly ranked nodes that are already activated by diffusion active between
stages. The gain arises when a saved seed is allocated to a node difficult to
reach via diffusion. Sequential seeding and a single stage approach are
compared using various seed ranking methods and diffusion parameters on real
complex networks. The experimental results indicate that, regardless of the
seed ranking method used, sequential seeding strategies deliver better coverage
than single stage seeding in about 90% of cases. Longer seeding sequences tend
to activate more nodes but they also extend the duration of diffusion. Various
variants of sequential seeding resolve the trade-off between the coverage and
speed of diffusion differently.


title: High-Redshift AGNs and the Next Decade of Chandra and XMM-Newton

abstract:
  We briefly review how X-ray observations of high-redshift active galactic
nuclei (AGNs) at z = 4-7 have played a critical role in understanding their
basic demographics as well as their physical processes; e.g., absorption by
nuclear material and winds, accretion rates, and jet emission. We point out
some key remaining areas of uncertainty, highlighting where further Chandra and
XMM-Newton observations/analyses, combined with new multiwavelength survey
data, can advance understanding over the next decade.


title: Compressed Hypothesis Testing: To Mix or Not to Mix?

abstract:
  In this paper, we study the problem of determining $k$ anomalous random
variables that have different probability distributions from the rest $(n-k)$
random variables. Instead of sampling each individual random variable
separately as in the conventional hypothesis testing, we propose to perform
hypothesis testing using mixed observations that are functions of multiple
random variables. We characterize the error exponents for correctly identifying
the $k$ anomalous random variables under fixed time-invariant mixed
observations, random time-varying mixed observations, and deterministic
time-varying mixed observations. For our error exponent characterization, we
introduce the notions of inner conditional Chernoff information and outer
conditional Chernoff information. It is demonstrated that mixed observations
can strictly improve the error exponents of hypothesis testing, over separate
observations of individual random variables. We further characterize the
optimal sensing vector maximizing the error exponents, which leads to explicit
constructions of the optimal mixed observations in special cases of hypothesis
testing for Gaussian random variables. These results show that mixed
observations of random variables can reduce the number of required samples in
hypothesis testing applications. In order to solve large-scale hypothesis
testing problems, we also propose efficient algorithms - LASSO based and
message passing based hypothesis testing algorithms.


title:
Chirality-driven orbital magnetic moments as a new probe for topological
  magnetic structures

abstract:
  When electrons are driven through unconventional magnetic structures, such as
skyrmions, they experience emergent electromagnetic fields that originate
several Hall effects. Independently, ground state emergent magnetic fields can
also lead to orbital magnetism, even without the spin-orbit interaction. The
close parallel between the geometric theories of the Hall effects and of the
orbital magnetization raises the question: does a skyrmion display topological
orbital magnetism? Here we first address the smallest systems with nonvanishing
emergent magnetic field, trimers, characterizing the orbital magnetic
properties from first-principles. Armed with this understanding, we study the
orbital magnetism of skyrmions, and demonstrate that the contribution driven by
the emergent magnetic field is topological. This means that the topological
contribution to the orbital moment does not change under continous deformations
of the magnetic structure. Furthermore, we use it to propose a new experimental
protocol for the identification of topological magnetic structures, by soft
x-ray spectroscopy.


title: GRS 1739-278 observed at very low luminosity with XMM-Newton and NuSTAR

abstract:
  We present a detailed spectral analysis of XMM-Newton and NuSTAR observations
of the accreting transient black hole GRS 1739-278 during a very faint low hard
state at ~0.02% of the Eddington luminosity (for a distance of 8.5 kpc and a
mass of 10 M_sun ). The broad-band X-ray spectrum between 0.5-60 keV can be
well-described by a power law continuum with an exponential cutoff. The
continuum is unusually hard for such a low luminosity, with a photon index of
Gamma = 1.39 +/- 0.04. We find evidence for an additional reflection component
from an optically thick accretion disk at the 98% likelihood level. The
reflection fraction is low with R_refl = 0.043(+0.033,-0.023). In combination
with measurements of the spin and inclination parameters made with NuSTAR
during a brighter hard state by Miller and co-workers, we seek to constrain the
accretion disk geometry. Depending on the assumed emissivity profile of the
accretion disk, we find a truncation radius of 15-35 Rg (5-12 R_ISCO ) at the
90% confidence limit. These values depend strongly on the assumptions and we
discuss possible systematic uncertainties.


title: Popular Matchings with Multiple Partners

abstract:
  Our input is a bipartite graph $G = (A \cup B,E)$ where each vertex in $A
\cup B$ has a preference list strictly ranking its neighbors. The vertices in
$A$ and in $B$ are called students and courses, respectively. Each student $a$
seeks to be matched to $\mathsf{cap}(a) \ge 1$ courses while each course $b$
seeks $\mathsf{cap}(b) \ge 1$ many students to be matched to it. The
Gale-Shapley algorithm computes a pairwise-stable matching (one with no
blocking edge) in $G$ in linear time. We consider the problem of computing a
popular matching in $G$ -- a matching $M$ is popular if $M$ cannot lose an
election to any matching where vertices cast votes for one matching versus
another. Our main contribution is to show that a max-size popular matching in
$G$ can be computed by the 2-level Gale-Shapley algorithm in linear time. This
is an extension of the classical Gale-Shapley algorithm and we prove its
correctness via linear programming.


title:
Well-posed Bayesian Inverse Problems with Infinitely-Divisible and
  Heavy-Tailed Prior Measures

abstract:
  We present a new class of prior measures in connection to $\ell_p$
regularization techniques when $p \in(0,1)$ which is based on the generalized
Gamma distribution. We show that the resulting prior measure is heavy-tailed,
non-convex and infinitely divisible. Motivated by this observation we discuss
the class of infinitely divisible prior measures and draw a connection between
their tail behavior and the tail behavior of their L{\'evy} measures. Next, we
use the laws of pure jump L{\'e}vy processes in order to define new classes of
prior measures that are concentrated on the space of functions with bounded
variation. These priors serve as an alternative to the classic total variation
prior and result in well-defined inverse problems. We then study the
well-posedness of Bayesian inverse problems in a general enough setting that
encompasses the above mentioned classes of prior measures. We establish that
well-posedness relies on a balance between the growth of the log-likelihood
function and the tail behavior of the prior and apply our results to special
cases such as additive noise models and linear problems. Finally, we discuss
some of the practical aspects of Bayesian inverse problems such as their
consistent approximation and present three concrete examples of well-posed
Bayesian inverse problems with heavy-tailed or stochastic process prior
measures.


title: Elasticity, Flexibility and Ideal Strength of Borophenes

abstract:
  We study the mechanical properties of two-dimensional (2D) boron, borophenes,
by first-principles calculations. The recently synthesized borophene with 1/6
concentration of hollow hexagons (HH) is shown to have in-plane modulus C up to
210 N/m and bending stiffness as low as D = 0.39 eV. Thus, its Foppl-von Karman
number per unit area, defined as C/D, reaches 568 nm-2, over twofold higher
than graphene's value, establishing the borophene as one of the most flexible
materials. Yet, the borophene has a specific modulus of 346 m2/s2 and ideal
strengths of 16 N/m, rivaling those (453 m2/s2 and 34 N/m) of graphene. In
particular, its structural fluxionality enabled by delocalized multi-center
chemical bonding favors structural phase transitions under tension, which
result in exceptionally small breaking strains yet highly ductile breaking
behavior. These mechanical properties can be further tailored by varying the HH
concentration, and the boron sheet without HHs can even be stiffer than
graphene against tension. The record high flexibility combined with excellent
elasticity in boron sheets can be utilized for designing composites and
flexible systems.


title: Predictive and Self Triggering for Event-based State Estimation

abstract:
  Event-based state estimation can achieve estimation quality comparable to
traditional time-triggered methods, but with a significantly lower number of
samples. In networked estimation problems, this reduction in sampling instants
does, however, not necessarily translate into better usage of the shared
communication resource. Because typical event-based approaches decide
instantaneously whether communication is needed or not, free slots cannot be
reallocated immediately, and hence remain unused. In this paper, novel
predictive and self triggering protocols are proposed, which give the
communication system time to adapt and reallocate freed resources. From a
unified Bayesian decision framework, two schemes are developed: self-triggers
that predict, at the current triggering instant, the next one; and predictive
triggers that indicate, at every time step, whether communication will be
needed at a given prediction horizon. The effectiveness of the proposed
triggers in trading off estimation quality for communication reduction is
compared in numerical simulations.


title:
Time Reversal Symmetry Breaking in the B Phase of the Heavy Fermion
  Superconductor PrOs$_4$Sb$_{12}$

abstract:
  We present polar Kerr effect measurements of the filled skutterudite
superconductor PrOs$_4$Sb$_{12}$. Simultaneous AC susceptibility measurements
allow us to observe the superconducting transition under the influence of
heating from the optical beam. A nonzero Kerr angle $\theta_K$ develops below
the superconducting transition, saturating at $\sim 300$ nrad at low
temperatures. This result is repeated across several measurements of multiple
samples. By extrapolating the measured $\theta_K(T)$ to zero optical power, we
are able to show that the Kerr angle onset temperature in one set of
measurements is consistent with the transition to the B phase at $T_{C2}$. We
discuss the possible explanations for this result and its impact on the
understanding of multi-phase and inhomogeneous superconductivity in
PrOs$_4$Sb$_{12}$.


title:
Alternative Form of Predictor Based Identification of LPV-SS Models with
  Innovation Noise

abstract:
  In this paper, we present an approach to identify linear parameter-varying
(LPV) systems with a state-space (SS) model structure in an innovation form
where the coefficient functions have static and affine dependency on the
scheduling signal. With this scheme, the curse of dimensionality problem is
reduced, compared to existing predictor based LPV subspace identification
schemes. The investigated LPV-SS model is reformulated into an equivalent
impulse response form, which turns out to be a moving average with exogenous
inputs (MAX) system. The Markov coefficient functions of the LPV-MAX
representation are multi-linear in the scheduling signal and its time-shifts,
contrary to the predictor based schemes where the corresponding LPV
auto-regressive with exogenous inputs system is multi-quadratic in the
scheduling signal and its time-shifts. In this paper, we will prove that under
certain conditions on the input and scheduling signals, the $\ell_2$ loss
function of the one-step-ahead prediction error for the LPV-MAX model has only
one unique minimum, corresponding to the original underlying system. Hence,
identifying the LPV-MAX model in the prediction error minimization framework
will be consistent and unbiased. The LPV-SS model is realized by applying an
efficient basis reduced Ho-Kalman realization on the identified LPV-MAX model.
The performance of the proposed scheme is assessed on a Monte Carlo simulation
study.


title:
A Tutorial on Distributed (Non-Bayesian) Learning: Problem, Algorithms
  and Results

abstract:
  We overview some results on distributed learning with focus on a family of
recently proposed algorithms known as non-Bayesian social learning. We consider
different approaches to the distributed learning problem and its algorithmic
solutions for the case of finitely many hypotheses. The original centralized
problem is discussed at first, and then followed by a generalization to the
distributed setting. The results on convergence and convergence rate are
presented for both asymptotic and finite time regimes. Various extensions are
discussed such as those dealing with directed time-varying networks, Nesterov's
acceleration technique and a continuum sets of hypothesis.


title:
Geometrical and Kinematic Parameters of the Jet of the Blazar S5 0716+71
  in a Helical-Jet Model

abstract:
  Periodic variations of the position angle of the inner jet of the blazar S5
0716+71 suggest a helical structure for the jet. The geometrical parameters of
a model helical jet are determined. It is shown that, when the trajectories of
the jet components are non-ballistic, the angle between their velocity vectors
and the line of sight lies in a broader interval than is the case for ballistic
motions of the components, in agreement with available estimates. The
contradictory results for the apparent speeds of components in the inner and
outer jet at epochs 2004 and 2008-2010 can be explained in such a model. The
ratio of the apparent speeds in the inner and outer jet is used to derive a
lower limit for the true speed of the components ($\beta>0.999$) and to
determine the pitch angle of the helical jet ($p=5.5^\circ$). The derived
parameters can give rise to the conditions required to observe high speeds
(right to 37$c$) for individual jet components.


title: On the Almost Everywhere Stability of Discrete-Time Dynamical Systems

abstract:
  For a dynamical system, it is known that the existence of a Lyapunov-type
density function, called Lyapunov density or Rantzer's density function,
implies convergence of Lebesgue almost all solutions to an equilibrium. Using
the duality between Frobenius-Perron and Koopmann operators, we generalize this
result from equilibrium to invariant sets, both for continuous- and
discrete-time. Furthermore, some redundant assumptions that exist in the
literature of almost everywhere stability for discrete-time, such as the local
stability of the attractor and the compactness of the state space, has been
removed.


title: Derivative Delay Embedding: Online Modeling of Streaming Time Series

abstract:
  The staggering amount of streaming time series coming from the real world
calls for more efficient and effective online modeling solution. For time
series modeling, most existing works make some unrealistic assumptions such as
the input data is of fixed length or well aligned, which requires extra effort
on segmentation or normalization of the raw streaming data. Although some
literature claim their approaches to be invariant to data length and
misalignment, they are too time-consuming to model a streaming time series in
an online manner. We propose a novel and more practical online modeling and
classification scheme, DDE-MGM, which does not make any assumptions on the time
series while maintaining high efficiency and state-of-the-art performance. The
derivative delay embedding (DDE) is developed to incrementally transform time
series to the embedding space, where the intrinsic characteristics of data is
preserved as recursive patterns regardless of the stream length and
misalignment. Then, a non-parametric Markov geographic model (MGM) is proposed
to both model and classify the pattern in an online manner. Experimental
results demonstrate the effectiveness and superior classification accuracy of
the proposed DDE-MGM in an online setting as compared to the state-of-the-art.


title:
On classical uniformization theorems for higher dimensional complex
  Kleinian groups

abstract:
  In this article we show that Bers' simultaneous uniformization as well as the
K\"oebe's retrosection theorem are not longer true for discrete groups of
projective transformations acting on the complex projective space.


title: Compressed Learning for Tactile Object Classification

abstract:
  The potential of large tactile arrays to improve robot perception for safe
operation in human-dominated environments and of high-resolution tactile arrays
to enable human-level dexterous manipulation is well accepted. However, the
increase in the number of tactile sensing elements introduces challenges
including wiring complexity, power consumption, and data processing. To help
address these challenges, we previously developed a tactile sensing technique
based compressed sensing that reduces hardware complexity and data
transmission, while allowing accurate reconstruction of the full-resolution
signal. In this paper, we apply tactile compressed sensing to the problem of
object classification. Specifically, we perform object classification on the
compressed tactile data. We evaluate our method using BubbleTouch, our tactile
array simulator. Our results show our approach achieves high classification
accuracy, even with compression factors up to 64.


title: Hanbury Brown and Twiss anticorrelation in disordered photonic lattices

abstract:
  We report measurements of Hanbury Brown and Twiss correlation of coherent
light transmitted through disordered one-dimensional photonic lattices.
Although such a lattice exhibits transverse Anderson localization when a single
input site is excited, uniform excitation precludes its observation. By
examining the Hanbury Brown--Twiss correlation for a uniformly excited
disordered lattice, we observe intensity anticorrelations associated with
photon antibunching--a signature of non-Gaussian statistics. Although the
measured average intensity distribution is uniform, transverse Anderson
localization nevertheless underlies the observed anticorrelation.


title: GMRT HI study of giant low surface brightness galaxies

abstract:
  We present HI observations of four giant low surface brightness (GLSB)
galaxies UGC 1378, UGC 1922, UGC 4422 and UM 163 using the Giant Meterwave
Radio Telescope (GMRT). We include HI results on UGC 2936, UGC 6614 and Malin 2
from literature. HI is detected from all the galaxies and the extent is roughly
twice the optical size; in UM 163, HI is detected along a broken disk
encircling the optical galaxy. We combine our results with those in literature
to further understand these systems. The main results are the following: (1)
The peak HI surface densities in GLSB galaxies are several times 10^21 cm^{-2}
. The HI mass is between 0.3 - 4 x 10^10 M_Sun/yr, dynamical mass ranges from a
few times 10^11 M_Sun/yr to a few times 10^12 M_Sun/yr. (2) The rotation curves
of GLSB galaxies are flat to the outermost measured point with rotation
velocities of the seven GLSB galaxies being between 225 and 432 km s^{-1}. (3)
Recent star formation traced by near-ultraviolet emission in five GLSB galaxies
in our sample appears to be located in rings around the galaxy centre. We
suggest that this could be due to a stochastic burst of star formation at one
location in the galaxy being propagated along a ring over a rotation period.
(4) The Hi is correlated with recent star formation in five of the seven GLSB
galaxies.


title: Benchmarking SciDB Data Import on HPC Systems

abstract:
  SciDB is a scalable, computational database management system that uses an
array model for data storage. The array data model of SciDB makes it ideally
suited for storing and managing large amounts of imaging data. SciDB is
designed to support advanced analytics in database, thus reducing the need for
extracting data for analysis. It is designed to be massively parallel and can
run on commodity hardware in a high performance computing (HPC) environment. In
this paper, we present the performance of SciDB using simulated image data. The
Dynamic Distributed Dimensional Data Model (D4M) software is used to implement
the benchmark on a cluster running the MIT SuperCloud software stack. A peak
performance of 2.2M database inserts per second was achieved on a single node
of this system. We also show that SciDB and the D4M toolbox provide more
efficient ways to access random sub-volumes of massive datasets compared to the
traditional approaches of reading volumetric data from individual files. This
work describes the D4M and SciDB tools we developed and presents the initial
performance results. This performance was achieved by using parallel inserts, a
in-database merging of arrays as well as supercomputing techniques, such as
distributed arrays and single-program-multiple-data programming.


title: Proving Linearizability via Branching Bisimulation

abstract:
  Linearizability and progress properties are key correctness notions for
concurrent objects. However, model checking linearizability has suffered from
the PSPACE-hardness of the trace inclusion problem. This paper proposes to
exploit branching bisimulation, a fundamental semantic equivalence relation
developed for process algebras which can be computed efficiently, in checking
these properties. A quotient construction is provided which results in huge
state space reductions. We confirm the advantages of the proposed approach on
more than a dozen benchmark problems.


title: Galaxy Simulation with Dust Formation and Destruction

abstract:
  We perform smoothed particle hydrodynamics (SPH) simulations of an isolated
galaxy with a new treatment for dust formation and destruction. To this aim, we
treat dust and metal production self-consistently with star formation and
supernova feedback. For dust, we consider a simplified model of grain size
distribution by representing the entire range of grain sizes with large and
small grains. We include dust production in stellar ejecta, dust destruction by
supernova (SN) shocks, grain growth by accretion and coagulation, and grain
disruption by shattering. We find that the assumption of fixed dust-to-metal
mass ratio becomes no longer valid when the galaxy is older than 0.2 Gyr, at
which point the grain growth by accretion starts to contribute to the nonlinear
rise of dust-to-gas ratio. As expected in our previous one-zone model,
shattering triggers grain growth by accretion since it increases the total
surface area of grains. Coagulation becomes significant when the galaxy age is
greater than $\sim$ 1 Gyr: at this epoch the abundance of small grains becomes
high enough to raise the coagulation rate of small grains. We further compare
the radial profiles of dust-to-gas ratio $(\mathcal{D})$ and dust-to-metal
ratio $(\mathcal{D}/Z)$ (i.e., depletion) at various ages with observational
data. We find that our simulations broadly reproduce the radial gradients of
dust-to-gas ratio and depletion. In the early epoch ($\lesssim 0.3$ Gyr), the
radial gradient of $\mathcal{D}$ follows the metallicity gradient with
$\mathcal{D}/Z$ determined by the dust condensation efficiency in stellar
ejecta, while the $\mathcal{D}$ gradient is steeper than the $Z$ gradient at
the later epochs because of grain growth by accretion. The framework developed
in this paper is applicable to any SPH-based galaxy evolution simulations
including cosmological ones.


title: The BigDAWG Polystore System and Architecture

abstract:
  Organizations are often faced with the challenge of providing data management
solutions for large, heterogenous datasets that may have different underlying
data and programming models. For example, a medical dataset may have
unstructured text, relational data, time series waveforms and imagery. Trying
to fit such datasets in a single data management system can have adverse
performance and efficiency effects. As a part of the Intel Science and
Technology Center on Big Data, we are developing a polystore system designed
for such problems. BigDAWG (short for the Big Data Analytics Working Group) is
a polystore system designed to work on complex problems that naturally span
across different processing or storage engines. BigDAWG provides an
architecture that supports diverse database systems working with different data
models, support for the competing notions of location transparency and semantic
completeness via islands and a middleware that provides a uniform multi--island
interface. Initial results from a prototype of the BigDAWG system applied to a
medical dataset validate polystore concepts. In this article, we will describe
polystore databases, the current BigDAWG architecture and its application on
the MIMIC II medical dataset, initial performance results and our future
development plans.


title:
Symmetry-protected topological phases with uniform computational power
  in one dimension

abstract:
  We investigate the usefulness of ground states of quantum spin chains with
symmetry-protected topological order (SPTO) for measurement-based quantum
computation. We show that, in spatial dimension one, if an SPTO phase supports
quantum wire, then, subject to an additional symmetry condition that is
satisfied in all cases so far investigated, it can also be used for quantum
computation.


title:
Estimation of the chiral magnetic effect considering the magnetic field
  response of the QGP medium

abstract:
  The magnetic field plays a major role in the searching of the chiral magnetic
effect in relativistic heavy-ion collisions. If the lifetime of the magnetic
field is too short, as expected by simulations of the field in the vacuum, the
chiral magnetic effect will be largely suppressed. However, the lifetime of the
magnetic field will become longer when the QGP medium response is considered.
We give an estimate of the effect, especially considering the magnetic field
response of the QGP medium, and compare it with the experimental results of
background-subtracted correlator $H$ at RHIC and LHC energies. The results show
that our method explains better for the experimental results at the top RHIC
energy than that of the LHC energy.


title: Tensor product of modules over a vertex algebra

abstract:
  We found a necessary and sufficient condition for the existence of the tensor
product of modules over a vertex algebra. We defined the notion of vertex
bilinear map and we provide two algebraic construction of the tensor product,
where one of them is of ring theoretical type. We show the relation between the
tensor product and the vertex homomorphisms. We prove the commutativity of the
tensor product. We also prove the associativity of the tensor product of
modules under certain necessary and sufficient condition. Finally, we show
certain functorial properties of the vertex homomorphims and the tensor
product.


title:
Chiral Huygens metasurfaces for nonlinear structuring of linearly
  polarized light

abstract:
  We report on a chiral nanostructure, which we term a "butterfly nanoantenna,"
that, when used in a metasurface, allows the direct conversion of a linearly
polarized beam into a nonlinear optical far-field of arbitrary complexity. The
butterfly nanoantenna exhibits field enhancement in its gap for every incident
linear polarization, which can be exploited to drive nonlinear optical emitters
within the gap, for the structuring of light within a frequency range not
accessible by linear plasmonics. As the polarization, phase and amplitude of
the field in the gap are highly controlled, nonlinear emitters within the gap
behave as an idealized Huygens source. A general framework is thereby proposed
wherein the butterfly nanoantennas can be arranged on a surface to produce a
highly structured far-field nonlinear optical beam with high purity. A third
harmonic Laguerre-Gauss beam carrying an optical orbital angular momentum of 41
is demonstrated as an example, through large-scale simulations on a
high-performance computing platform of the full plasmonic metasurface with an
area large enough to contain up to 3600 nanoantennas.


title: Controlling Strain Bursts and Avalanches at the Nano-to-Micro Scale

abstract:
  We demonstrate, through 3-dimensional discrete dislocation dynamics
simulations, that the com- plex dynamical response of nano and micro crystals
to external constraints can be tuned. Under load rate control, strain bursts
are shown to exhibit scale-free avalanche statistics, similar to critical
phenomena in many physical systems. For the other extreme of displacement rate
control, strain burst response transitions to quasi-periodic oscillations,
similar to stick-slip earthquakes. External load mode control is shown to
enable a qualitative transition in the complex collective dynamics of
dislocations from self-organized criticality to quasi-periodic oscillations.


title: An information-based classification of Elementary Cellular Automata

abstract:
  A novel, information-based classification of elementary cellular automata is
proposed that circumvents the problems associated with isolating whether
complexity is in fact intrinsic to a dynamical rule, or if it arises merely as
a product of a complex initial state. Transfer entropy variations processed by
the system split the 256 elementary rules into three information classes, based
on sensitivity to initial conditions. These classes form a hierarchy such that
coarse-graining transitions observed among elementary cellular automata rules
predominately occur within each information- based class, or much more rarely,
down the hierarchy.


abstract:
  Let $P$ be the set of all prime numbers, ${q_1},{q_2}, \cdots ,{q_m} \in P$,
$P_k$ be the k-th $(k = 1,2, \cdots m)$ element of $P$ in ascending order of
size, ${\alpha _1},{\alpha _2}, \cdots ,{\alpha _m}$ be positive integers, and
${\beta _1},{\beta _2}, \cdots ,{\beta _m}$ is a permutation of ${\alpha
_1},{\alpha _2}, \cdots ,{\alpha _m}$ with ${\beta _1} \ge {\beta _2} \ge
\cdots \ge {\beta _m}$, The following results are given in this paper:
  (i) The following inequality is true:
  ${e^\gamma }\log \log \prod\limits_{k = 1}^m {q_k^{{\alpha _k}}} -
\prod\limits_{k = 1}^m {\frac{{{q_k} - {\textstyle{1 \over {q_k^{{\alpha
_k}}}}}}}{{{q_k} - 1}}} \ge {e^\gamma }\log \log \prod\limits_{k = 1}^m
{p_k^{{\beta _k}}} - \prod\limits_{k = 1}^m {\frac{{{p_k} - {\textstyle{1 \over
{p_k^{{\beta _k}}}}}}}{{{p_k} - 1}}}$.
  (ii) If $n = \prod\limits_{k = 1}^m {p_k^{{\beta _k}}}= {\left(
{\prod\limits_{k = 1}^m {{p_k}} } \right)^{1 + {\varepsilon _m}(n)}}$, $\mathop
{\lim }\limits_{m \to \infty } {\varepsilon _m}(n) > 0$ or $\mathop {\lim
}\limits_{m \to \infty } {\varepsilon _m}(n) = + \infty$, then $\mathop {\lim
}\limits_{m \to \infty } ({e^\gamma }n\log \log n - \sigma (n)) > 0$ . Where
$\{ {\beta _k}\}$ is a sequence, ${\beta _k} \in N$, ${\beta _1} \ge {\beta _2}
\ge \cdots \ge {\beta _m}$, $\sigma (n) = \sum\limits_{\left. d \right|n} d$,
and $\gamma$ is the Euler constant.
  (iii) The probability of Riemann's hypothesis being true is equal to 1.
  In addition, two results are given when $\mathop {\lim }\limits_{m \to \infty
} {\varepsilon _m}(n) = 0$.


title: Discrete Anderson Speckle

abstract:
  When a disordered array of coupled waveguides is illuminated with an extended
coherent optical field, discrete speckle develops: partially coherent light
with a granular intensity distribution on the lattice sites. The same paradigm
applies to a variety of other settings in photonics, such as imperfectly
coupled resonators or fibers with randomly coupled cores. Through numerical
simulations and analytical modeling, we uncover a set of surprising features
that characterize discrete speckle in one- and two-dimensional lattices known
to exhibit transverse Anderson localization. Firstly, the fingerprint of
localization is embedded in the fluctuations of the discrete speckle and is
revealed in the narrowing of the spatial coherence function. Secondly, the
transverse coherence length (or speckle grain size) is frozen during
propagation. Thirdly, the axial coherence depth is independent of the axial
position, thereby resulting in a coherence voxel of fixed volume independently
of position. We take these unique features collectively to define a distinct
regime that we call discrete Anderson speckle.


title:
A characterization of $L_{2}$ mixing and hypercontractivity via hitting
  times and maximal inequalities

abstract:
  There are several works characterizing the total-variation mixing time of a
reversible Markov chain in term of natural probabilistic concepts such as
stopping times and hitting times. In contrast, there is no known analog for the
$L_{2}$ mixing time, $\tau_{2}$ (while there are sophisticated analytic tools
to bound $ \tau_2$, in general they do not determine $\tau_2$ up to a constant
factor and they lack a probabilistic interpretation). In this work we show that
$\tau_2$ can be characterized up to a constant factor using hitting times
distributions. We also derive a new extremal characterization of the
Log-Sobolev constant, $c_{\mathrm{LS}}$, as a weighted version of the spectral
gap. This characterization yields a probabilistic interpretation of
$c_{\mathrm{LS}}$ in terms of a hitting time version of hypercontractivity. As
applications of our results, we show that (1) for every reversible Markov
chain, $\tau_2$ is robust under addition of self-loops with bounded weights,
and (2) for weighted nearest neighbor random walks on trees, $\tau_2 $ is
robust under bounded perturbations of the edge weights.


title: Discrete Sums of Geometric Brownian Motions, Annuities and Asian Options

abstract:
  The discrete sum of geometric Brownian motions plays an important role in
modeling stochastic annuities in insurance. It also plays a pivotal role in the
pricing of Asian options in mathematical finance. In this paper, we study the
probability distributions of the infinite sum of geometric Brownian motions,
the sum of geometric Brownian motions with geometric stopping time, and the
finite sum of the geometric Brownian motions. These results are extended to the
discrete sum of the exponential L\'evy process. We derive tail asymptotics and
compute numerically the asymptotic distribution function. We compare the
results against the known results for the continuous time integral of the
geometric Brownian motion up to an exponentially distributed time. The results
are illustrated with numerical examples for life annuities with discrete
payments, and Asian options.


title: Short Maturity Asian Options in Local Volatility Models

abstract:
  We present a rigorous study of the short maturity asymptotics for Asian
options with continuous-time averaging, under the assumption that the
underlying asset follows a local volatility model. The asymptotics for
out-of-the-money, in-the-money, and at-the-money cases are derived, considering
both fixed strike and floating strike Asian options. The asymptotics for the
out-of-the-money case involves a non-trivial variational problem which is
solved completely. We present an analytical approximation for Asian options
prices, and demonstrate good numerical agreement of the asymptotic results with
the results of Monte Carlo simulations and benchmark test cases in the
Black-Scholes model for option parameters relevant in practical applications.


title: Informative Planning and Online Learning with Sparse Gaussian Processes

abstract:
  A big challenge in environmental monitoring is the spatiotemporal variation
of the phenomena to be observed. To enable persistent sensing and estimation in
such a setting, it is beneficial to have a time-varying underlying
environmental model. Here we present a planning and learning method that
enables an autonomous marine vehicle to perform persistent ocean monitoring
tasks by learning and refining an environmental model. To alleviate the
computational bottleneck caused by large-scale data accumulated, we propose a
framework that iterates between a planning component aimed at collecting the
most information-rich data, and a sparse Gaussian Process learning component
where the environmental model and hyperparameters are learned online by taking
advantage of only a subset of data that provides the greatest contribution. Our
simulations with ground-truth ocean data shows that the proposed method is both
accurate and efficient.


title: Distilling an Ensemble of Greedy Dependency Parsers into One MST Parser

abstract:
  We introduce two first-order graph-based dependency parsers achieving a new
state of the art. The first is a consensus parser built from an ensemble of
independently trained greedy LSTM transition-based parsers with different
random initializations. We cast this approach as minimum Bayes risk decoding
(under the Hamming cost) and argue that weaker consensus within the ensemble is
a useful signal of difficulty or ambiguity. The second parser is a
"distillation" of the ensemble into a single model. We train the distillation
parser using a structured hinge loss objective with a novel cost that
incorporates ensemble uncertainty estimates for each possible attachment,
thereby avoiding the intractable cross-entropy computations required by
applying standard distillation objectives to problems with structured outputs.
The first-order distillation parser matches or surpasses the state of the art
on English, Chinese, and German.


title:
Sub-thermal to super-thermal light statistics from a disordered lattice
  via deterministic control of excitation symmetry

abstract:
  Monochromatic coherent light traversing a disordered photonic medium evolves
into a random field whose statistics are dictated by the disorder level. Here
we demonstrate experimentally that light statistics can be deterministically
tuned in certain disordered lattices, even when the disorder level is held
fixed, by controllably breaking the excitation symmetry of the lattice modes.
We exploit a lattice endowed with disorder-immune chiral symmetry in which the
eigenmodes come in skew-symmetric pairs. If a single lattice site is excited, a
"photonic thermalization gap" emerges: the realm of sub-thermal light
statistics is inaccessible regardless of the disorder level. However, by
exciting two sites with a variable relative phase, as in a traditional two-path
interferometer, the chiral symmetry is judiciously broken and interferometric
control over the light statistics is exercised, spanning sub-thermal and
super-thermal regimes. These results may help develop novel incoherent lighting
sources from coherent lasers.


title: Lattice realization of the generalized chiral symmetry in two dimensions

abstract:
  While it has been pointed out that the chiral symmetry, which is important
for the Dirac fermions in graphene, can be generalized to tilted Dirac fermions
as in organic metals, such a generalized symmetry was so far defined only for a
continuous low-energy Hamiltonian. Here we show that the generalized chiral
symmetry can be rigorously defined for lattice fermions as well. A key concept
is a continuous "algebraic deformation" of Hamiltonians, which generates
lattice models with the generalized chiral symmetry from those with the
conventional chiral symmetry. This enables us to explicitly express zero modes
of the deformed Hamiltonian in terms of that of the original Hamiltonian.
Another virtue is that the deformation can be extended to non-uniform systems,
such as fermion-vortex systems and disordered systems. Application to fermion
vortices in a deformed system shows how the zero modes for the conventional
Dirac fermions with vortices can be extended to the tilted case.


title: Field-like spin orbit torque in ultra-thin polycrystalline FeMn films

abstract:
  Field-like spin orbit torque in FeMn/Pt bilayers with ultra-thin
polycrystalline FeMn has been characterized through planar Hall effect
measurements. A large effective field is obtained for FeMn in the thickness
range of 2 to 5 nm. The experimental observations can be reasonably accounted
for by using a macro-spin model under the assumption that the FeMn layer is
composed of two spin sublattices with unequal magnetizations. The large
effective field corroborates the spin Hall origin of the effective field
considering the much smaller uncompensated net moments in FeMn as compared to
NiFe. The effective absorption of spin current by FeMn is further confirmed by
the fact that spin current generated by Pt in NiFe/FeMn/Pt trilayers can only
travel through the FeMn layer with a thickness of 1 to 4 nm. By quantifying the
field-like effective field induced in NiFe, a spin diffusion length of 2 nm is
estimated in FeMn, in consistence with values reported in literature by
ferromagnetic resonance and spin-pumping experiments.


title:
The stability of the higher topological complexity of real projective
  spaces: an approach to their immersion dimension

abstract:
  The $s$-th higher topological complexity of a space $X$, $TC_s(X)$, can be
estimated from above by homotopical methods, and from below by homological
methods. We give a thorough analysis of the gap between such estimates when
$X=RP^m$, the real projective space of dimension $m.$ In particular, we
describe a number $r(m)$, which depends on the structure of zeros and ones in
the binary expansion of $m$, and with the property that $TC_s(RP^m)$ is given
by $sm$ with an error of at most one provided $s \geq r(m)$ and $m \not\equiv 3
\bmod 4$ (the error vanishes for even $m$). The latter fact appears to be
closely related to the estimation of the Euclidean immersion dimension of
$RP^m$. We illustrate the phenomenon in the case $m=3 \cdot 2^a$.


title: Thickness dependence of spin Hall magnetoresistance in FeMn/Pt bilayers

abstract:
  We investigated spin Hall magnetoresistance in FeMn/Pt bilayers, which was
found to be one order of magnitude larger than that of heavy metal and
insulating ferromagnet or antiferromagnet bilayer systems, and comparable to
that of NiFe/Pt bilayers. The spin Hall magnetoresistance shows a non-monotonic
dependence on the thicknesses of both FeMn and Pt. The former can be accounted
for by the thickness dependence of net magnetization in FeMn thin films,
whereas the latter is mainly due to spin accumulation and diffusion in Pt.
Through analysis of the Pt thickness dependence, the spin Hall angle, spin
diffusion length of Pt and the real part of spin mixing conductance were
determined to be 0.2, 1.1 nm, and $5.5 * 10^{14} {\Omega}^{-1} m^{-2}$,
respectively. The results corroborate the spin orbit torque effect observed in
this system recently.


title:
Electron elastic scattering off polarizable $A$@C$_{60}$: The complete
  study within a particular theory

abstract:
  A deeper insight into electron elastic scattering off endohedral fullerenes
$A$@C$_{60}$ is provided. The study accounts for polarization of both the
encapsulated atom $A$ and C$_{60}$ cage by an incident electron. It is carried
out in the framework of the combination of both a model and the first-principle
approximations. A core principle of the model is that the C$_{60}$ cage itself
is presented by an attractive spherical potential of a certain inner radius,
thickness, and depth. The main idea of the first-principle approximation is
that the polarization of $A$@C$_{60}$ by an incident electron is accounted with
the help of the Dyson equation for the self-energy part of the Green's function
of an incident electron. Calculations are performed for, and comparison is made
between the individual cases: (a) when $A$@C$_{60}$ is regarded as a static
system, (b) when C$_{60}$ is a static cage, but the encapsulated atom is
polarizable, (c) when both C$_{60}$ and $A$ are polarized simultaneously but
independently of each other, and (d), as the most general scenario, when
polarizabilities of C$_{60}$ and $A$ are coupled. Spectacular similarities and
discrepancies between results of each of the exploited approximations are
demonstrated. Revealed features of the overall significant impact of
$A$@C$_{60}$ polarization by an incident electron on its elastic scattering off
$A$@C$_{60}$ are demonstrated. Choosing Ne, Xe, and Ba as "probing" atoms, the
dependence of $e + A@{\rm C_{60}}$ scattering on the size and polarizability of
the encapsulated atom is unraveled.


title:
A Character-level Convolutional Neural Network for Distinguishing
  Similar Languages and Dialects

abstract:
  Discriminating between closely-related language varieties is considered a
challenging and important task. This paper describes our submission to the DSL
2016 shared-task, which included two sub-tasks: one on discriminating similar
languages and one on identifying Arabic dialects. We developed a
character-level neural network for this task. Given a sequence of characters,
our model embeds each character in vector space, runs the sequence through
multiple convolutions with different filter widths, and pools the convolutional
representations to obtain a hidden vector representation of the text that is
used for predicting the language or dialect. We primarily focused on the Arabic
dialect identification task and obtained an F1 score of 0.4834, ranking 6th out
of 18 participants. We also analyze errors made by our system on the Arabic
data in some detail, and point to challenges such an approach is faced with.


title: Evolution of Cooperation on Temporal Networks

abstract:
  The structure of social networks is a key determinant in fostering
cooperation and other altruistic behavior among naturally selfish individuals.
However, most real social interactions are temporal, being both finite in
duration and spread out over time. This raises the question of whether stable
cooperation can form despite an intrinsically fragmented social fabric. Here we
develop a framework to study the evolution of cooperation on temporal networks
in the setting of the classic Prisoner's Dilemma. By analyzing both real and
synthetic datasets, we find that temporal networks generally facilitate the
evolution of cooperation compared to their static counterparts. More
interestingly, we find that the intrinsic human interactive pattern like bursty
behavior impedes the evolution of cooperation. Finally, we introduce a measure
to quantify the temporality present in networks and demonstrate that there is
an intermediate level of temporality that boosts cooperation most. Our results
open a new avenue for investigating the evolution of cooperation in more
realistic structured populations.


title:
Electrostatic deflection of a molecular beam of massive neutral
  particles: Fully field-oriented polar molecules within superfluid
  nanodroplets

abstract:
  Electric deflection measurements on liquid helium nanodroplets doped with
individual polar molecules demonstrate that the cold superfluid matrix enables
full orientation of the molecular dipole along the external field. This
translates into a deflection force which is increased enormously by comparison
with typical deflection experiments, and it becomes possible to measurably
deflect neutral doped droplets with masses of tens to hundreds of thousands of
Daltons. This approach permits preparation and study of continuous fluxes of
fully oriented polar molecules and is broadly and generally applicable,
including to complex and biological molecules. It is shown that the dipole
moments of internally cryogenically cold molecules can be directly determined
from a deflection measurement on the doped nanodroplet beam.


title:
The transparency of graphene and other direct-gap two dimensional
  materials

abstract:
  Graphene and other two-dimensional materials display remarkable optical
properties, including a simple light transparency of $T \approx 1 - \pi \alpha$
for light in the visible region. Most theoretical rationalizations of this
"universal" opacity employ a model coupling light to the electron's crystal
momentum and put emphasis on the linear dispersion of the graphene bands.
However, such a formulation of interband absorption is not allowable within
band structure theory, because it conflates the crystal momentum label with the
canonical momentum operator. We show that the physical origin of the optical
behavior of graphene can be explained within a straightforward picture with the
correct use of canonical momentum coupling. Its essence lies in the
two-dimensional character of the density of states rather than in the precise
dispersion relation, and therefore the discussion is applicable to other
systems such as semiconductor membranes. At higher energies the calculation
predicts a peak corresponding to a van Hove singularity as well as a specific
asymmetry in the absorption spectrum of graphene, in agreement with previous
results.


title: Topology, Holonomy, and Quantum Walks

abstract:
  We present a review on the progress in the understanding and characterization
of holonomy and topology of a discrete-time quantum walk architecture,
consisting of a unitary step given by a sequence of two non-commuting rotations
in parameter space \cite{Puentesarxiv}. Unlike other similar systems recently
studied in detail in the literature, this system does not present continous 1D
topological boundaries, it only presents a discrete number of Dirac points
where the quasi- energy gap closes. At these discrete points the topological
winding number is not defined. Therefore, such discrete points represent
topological boundaries of dimension zero, and they endow the system with a
non-trivial topology. We illustrate the non-trivial character of the system by
calculating the Zak phase. We also propose a suitable experimental scheme to
implement these ideas, and we present preliminary experimental data.


title:
Modelling and mitigating refractive propagation effects in precision
  pulsar timing observations

abstract:
  To obtain the most accurate pulse arrival times from radio pulsars, it is
necessary to correct or mitigate the effects of the propagation of radio waves
through the warm and ionised interstellar medium. We examine both the strength
of propagation effects associated with large-scale electron-density variations
and the methodology used to estimate infinite-frequency arrival times. Using
simulations of two-dimensional phase-varying screens, we assess the strength
and non-stationarity of timing perturbations associated with large-scale
density variations. We identify additional contributions to arrival times that
are stochastic in both radio frequency and time and therefore not amenable to
correction solely using times of arrival. We attribute this to the frequency
dependence of the trajectories of the propagating radio waves. We find that
this limits the efficacy of low-frequency (metre-wavelength) observations.
Incorporating low-frequency pulsar observations into precision timing campaigns
is increasingly problematic for pulsars with larger dispersion measures.


title: Dynamic Pricing in High-dimensions

abstract:
  We study the pricing problem faced by a firm that sells a large number of
products, described via a wide range of features, to customers that arrive over
time. Customers independently make purchasing decisions according to a general
choice model that includes products features and customers' characteristics,
encoded as $d$-dimensional numerical vectors, as well as the price offered. The
parameters of the choice model are a priori unknown to the firm, but can be
learned as the (binary-valued) sales data accrues over time. The firm's
objective is to minimize the regret, i.e., the expected revenue loss against a
clairvoyant policy that knows the parameters of the choice model in advance,
and always offers the revenue-maximizing price. This setting is motivated in
part by the prevalence of online marketplaces that allow for real-time pricing.
We assume a structured choice model, parameters of which depend on $s_0$ out of
the $d$ product features. We propose a dynamic policy, called Regularized
Maximum Likelihood Pricing (RMLP) that leverages the (sparsity) structure of
the high-dimensional model and obtains a logarithmic regret in $T$. More
specifically, the regret of our algorithm is of $O(s_0 \log d \cdot \log T)$.
Furthermore, we show that no policy can obtain regret better than $O(s_0 (\log
d + \log T))$.


title:
Ordered set partitions, generalized coinvariant algebras, and the Delta
  Conjecture

abstract:
  The symmetric group $\mathfrak{S}_n$ acts on the polynomial ring
$\mathbb{Q}[\mathbf{x}_n] = \mathbb{Q}[x_1, \dots, x_n]$ by variable
permutation. The invariant ideal $I_n$ is the ideal generated by all
$\mathfrak{S}_n$-invariant polynomials with vanishing constant term. The
quotient $R_n = \frac{\mathbb{Q}[\mathbf{x}_n]}{I_n}$ is called the coinvariant
algebra. The coinvariant algebra $R_n$ has received a great deal of study in
algebraic and geometric combinatorics. We introduce a generalization $I_{n,k}
\subseteq \mathbb{Q}[\mathbf{x}_n]$ of the ideal $I_n$ indexed by two positive
integers $k \leq n$. The corresponding quotient $R_{n,k} :=
\frac{\mathbb{Q}[\mathbf{x}_n]}{I_{n,k}}$ carries a graded action of
$\mathfrak{S}_n$ and specializes to $R_n$ when $k = n$. We generalize many of
the nice properties of $R_n$ to $R_{n,k}$. In particular, we describe the
Hilbert series of $R_{n,k}$, give extensions of the Artin and Garsia-Stanton
monomial bases of $R_n$ to $R_{n,k}$, determine the reduced Gr\"obner basis for
$I_{n,k}$ with respect to the lexicographic monomial order, and describe the
graded Frobenius series of $R_{n,k}$. Just as the combinatorics of $R_n$ are
controlled by permutations in $\mathfrak{S}_n$, we will show that the
combinatorics of $R_{n,k}$ are controlled by ordered set partitions of $\{1, 2,
\dots, n\}$ with $k$ blocks. The {\em Delta Conjecture} of Haglund, Remmel, and
Wilson is a generalization of the Shuffle Conjecture in the theory of diagonal
coinvariants. We will show that the graded Frobenius series of $R_{n,k}$ is (up
to a minor twist) the $t = 0$ specialization of the combinatorial side of the
Delta Conjecture. It remains an open problem to give a bigraded
$\mathfrak{S}_n$-module $V_{n,k}$ whose Frobenius image is even conjecturally
equal to any of the expressions in the Delta Conjecture; our module $R_{n,k}$
solves this problem in the specialization $t = 0$.


title: Incentivizing Energy Trading for Interconnected Microgrids

abstract:
  In this paper, we study the interactions among interconnected autonomous
microgrids, and propose a joint energy trading and scheduling strategy. Each
interconnected microgrid not only schedules its local power supply and demand,
but also trades energy with other microgrids in a distribution network.
Specifically, microgrids with excessive renewable generations can trade with
other microgrids in deficit of power supplies for mutual benefits. Since
interconnected microgrids operate autonomously, they aim to optimize their own
performance and expect to gain benefits through energy trading. We design an
incentive mechanism using Nash bargaining theory to encourage proactive energy
trading and fair benefit sharing. We solve the bargaining problem by
decomposing it into two sequential problems on social cost minimization and
trading benefit sharing, respectively. For practical implementation, we propose
a decentralized solution method with minimum information exchange overhead.
Numerical studies based on realistic data demonstrate that the total cost of
the interconnected-microgrids operation can be reduced by up to 13.2% through
energy trading, and an individual participating microgrid can achieve up to
29.4% reduction in its cost through energy trading.


title:
Gone with the Wind: Nonlinear Guidance for Small Fixed-Wing Aircrafts in
  Arbitrarily Strong Windfields

abstract:
  The recent years have witnessed increased development of small, autonomous
fixed-wing Unmanned Aerial Vehicles (UAVs). In order to unlock widespread
applicability of these platforms, they need to be capable of operating under a
variety of environmental conditions. Due to their small size, low weight, and
low speeds, they require the capability of coping with wind speeds that are
approaching or even faster than the nominal airspeed. In this paper we present
a principled nonlinear guidance strategy, addressing this problem. More
broadly, we propose a methodology for the high-level control of non-holonomic
unicycle-like vehicles in the presence of strong flowfields (e.g. winds,
underwater currents) which may outreach the maximum vehicle speed. The proposed
strategy guarantees convergence to a safe and stable vehicle configuration with
respect to the flowfield, while preserving some tracking performance with
respect to the target path. Evaluations in simulations and a challenging
real-world flight experiment in very windy conditions confirm the feasibility
of the proposed guidance approach.


title: Mass-Imbalanced Superconductivity in Effective Two-Channel Kondo Lattice

abstract:
  We propose that mass-imbalanced superconductivity is realized in an effective
two-channel Kondo lattice, and its characteristic property appears in
electromagnetic responses such as the Meissner effect. Starting from an
effective two-channel Kondo lattice model as a low-energy effective theory, and
approximating it with two mean-field order parameter components in a
self-consistent fashion, it is shown that the balance of the two components is
sensitively reflected in the magnitude of the Meissner kernel, while
thermodynamic properties are little affected by the balance. This remarkable
behavior is understood by the localized character of one partner in the Cooper
pair, namely, the effect of the mass imbalance. We briefly mention the
relevance to the huge enhancement of the upper critical field under pressure
observed in Pr 1-2-20 systems.


title:
Intertwining operators for non self-adjoint Hamiltonians and bicoherent
  states

abstract:
  This paper is devoted to the construction of what we will call {\em exactly
solvable models}, i.e. of quantum mechanical systems described by an
Hamiltonian $H$ whose eigenvalues and eigenvectors can be explicitly
constructed out of some {\em minimal ingredients}. In particular, motivated by
PT-quantum mechanics, we will not insist on any self-adjointness feature of the
Hamiltonians considered in our construction. We also introduce the so-called
bicoherent states, we analyze some of their properties and we show how they can
be used for quantizing a system. Some examples, both in finite and in
infinite-dimensional Hilbert spaces, are discussed.


title:
Classification of infrastructure networks by neighborhood degree
  distribution

abstract:
  A common way of classifying network connectivity is the association of the
nodal degree distribution to specific probability distribution models. During
the last decades, researchers classified many networks using the Poisson or
Pareto distributions. Urban infrastructures, like transportation (railways,
roads, etc.) and distribution (gas, water, energy, etc.) systems, are peculiar
networks strongly constrained by spatial characteristics of the environment
where they are constructed. Consequently, the nodal degree of such networks
spans very small ranges not allowing a reliable classification using the nodal
degree distribution. In order to overcome this problem, we here (i) define the
neighborhood degree, equal to the sum of the nodal degrees of the nearest
topological neighbors, the adjacent nodes and (ii) propose to use neighborhood
degree to classify infrastructure networks. Such neighborhood degree spans a
wider range of degrees than the standard one allowing inferring the
probabilistic model in a more reliable way, from a statistical standpoint. In
order to test our proposal, we here analyze twenty-two real water distribution
networks, built in different environments, demonstrating that the Poisson
distribution generally models very well their neighborhood degree
distributions. This result seems consistent with the less reliable
classification achievable with the scarce information using the standard nodal
degree distribution.


title:
Quantum steerability: characterization, quantification, superactivation
  and unbounded amplification

abstract:
  Quantum steering, also called Einstein-Podolsky-Rosen steering, is the
intriguing phenomenon associated with the ability of spatially separated
observers to steer---by means of local measurements---the set of conditional
quantum states accessible by a distant party. In the light of quantum
information, all steerable quantum states are known to be resources for quantum
information processing tasks. Here, via a quantity dubbed steering fraction, we
derive a simple, but general criterion that allows one to identify quantum
states that can exhibit quantum steering, thus making an important step towards
the characterization of steerable quantum states. The criterion, in turn, also
provides upper bounds on the largest steering-inequality violation achievable
by arbitrary finite-dimensional maximally entangled states. For the
quantification of steerability, we prove that a strengthened version of the
steering fraction is a convex steering monotone and demonstrate how it is
related to two others, namely, steerable weight and steering robustness. Using
these tools, we further demonstrate the superactivation of steerability, i.e.,
we show how the steerability of certain entangled, but unsteerable quantum
states can be recovered by allowing joint measurements on multiple copies of
the same state. In particular, our approach allows one to explicitly construct
a steering inequality to manifest this phenomenon. Finally, we prove that there
exist quantum states (including some unsteerable under projective measurements)
whose steering-inequality violation can be arbitrarily amplified by allowing
joint measurements on three copies of the same state. For completeness, we also
demonstrate how the largest steering-inequality violation can be used to bound
the largest Bell-inequality violation and derive, analogously, a simple
sufficient condition for Bell-nonlocality from the latter.


title:
Scaling of sub-gap excitations in a superconductor-semiconductor
  nanowire quantum dot

abstract:
  A quantum dot coupled to a superconducting contact provides a tunable
artificial analogue of a magnetic atom in a superconductor, a paradigmatic
quantum impurity problem. We realize such a system with an InAs semiconductor
nanowire contacted by an Al-based superconducting electrode. We use an
additional normal-type contact as weakly coupled tunnel probe to perform
tunneling spectroscopy measurements of the elementary sub-gap excitations,
known as Andreev bound states or Yu-Shiba-Rusinov states. We demonstrate that
the energy of these states, $\zeta$, scales with the ratio between the Kondo
temperature, $T_K$, and the superconducting gap, $\Delta$. $\zeta$ vanishes for
$T_K/\Delta \approx 0.6$, denoting a quantum phase transition between spin
singlet and doublet ground states. By further leveraging the gate control over
the quantum dot parameters, we determine the singlet-doublet phase boundary in
the stability diagram of the system. Our experimental results show remarkable
quantitative agreement with numerical renormalization group calculations.


title: New LUX result compensates LHC searches for exotic quarks

abstract:
  The scenario of the compressed mass spectrum between heavy quark and dark
matter is a challenge for LHC searches. However, the elastic scattering cross
section between dark matter and nuclei in dark matter direct detection
experiments can be enhanced with nearly degenerate masses between heavy quarks
and dark matter. In this paper, we illustrate such scenario with a vector dark
matter, using the latest result from LUX 2016. The mass constraints on heavy
quarks can be more stringent than current limits from LHC, unless the coupling
strength is very small. However, the compress mass spectrum with allowed tiny
coupling strength makes the decay lifetime of heavy quarks longer than the time
scale of QCD hadronization.


title:
Coherent Manipulation of Thermal Transport by Tunable Electron-Photon
  and Electron-Phonon Interaction

abstract:
  We propose a system where coherent thermal transport between two reservoirs
in non-galvanic contact is modulated by independently tuning the
electron-photon and the electron-phonon coupling. The scheme is based on two
gate-controlled electrodes capacitively coupled through a dc-SQUID as
intermediate phase-tunable resonator. Thereby the electron-photon interaction
is modulated by controlling the flux threading the dc-SQUID and the impedance
of the two reservoirs, while the electron-phonon coupling is tuned by
controlling the charge carrier concentration in the electrodes. To
quantitatively evaluate the behavior of the system we propose to exploit
graphene reservoirs. In this case, the scheme can work at temperatures reaching
1 K, with unprecedented temperature modulations as large as 245 mK,
transmittance up to 99% and energy conversion efficiency up to 50%. Finally,
the accuracy of heat transport control allows to use this system as an
experimental tool to determine the electron-phonon coupling in two dimensional
electronic systems (2DES).


title:
An Investigation of Recurrent Neural Architectures for Drug Name
  Recognition

abstract:
  Drug name recognition (DNR) is an essential step in the Pharmacovigilance
(PV) pipeline. DNR aims to find drug name mentions in unstructured biomedical
texts and classify them into predefined categories. State-of-the-art DNR
approaches heavily rely on hand crafted features and domain specific resources
which are difficult to collect and tune. For this reason, this paper
investigates the effectiveness of contemporary recurrent neural architectures -
the Elman and Jordan networks and the bidirectional LSTM with CRF decoding - at
performing DNR straight from the text. The experimental results achieved on the
authoritative SemEval-2013 Task 9.1 benchmarks show that the bidirectional
LSTM-CRF ranks closely to highly-dedicated, hand-crafted systems.


title:
The reconstruction of sound speed in the Marmousi model by the boundary
  control method

abstract:
  We present the results on numerical testing of the Boundary Control Method in
the sound speed determination for the acoustic equation on semiplane. This
method for solving multidimensional inverse problems requires no a priory
information about the parameters under reconstruction. The application to the
realistic Marmousi model demonstrates that the boundary control method is
workable in the case of complicated and irregular field of acoustic rays. By
the use of the chosen boundary controls, an `averaged' profile of the sound
speed is recovered (the relative error is about $10-15\%$). Such a profile can
be further utilized as a starting approximation for high resolution iterative
reconstruction methods.


title: Exploring fundamental physics with neutron stars

abstract:
  In this lecture, we give a first introduction to neutron stars, based on
fundamental physical principles. After outlining their outstanding macroscopic
properties, as obtained from observations, we infer the extreme conditions of
matter in their interiors. We then describe two crucial physical phenomena
which characterize compact stars, namely the gravitational stability of
strongly degenerate matter and the neutronization of nuclear matter with
increasing density, and explain how the formation and properties of neutron
stars are a direct consequence of the extreme compression of matter under
strong gravity. Finally, we describe how multi-wavelength observations of
different external macroscopic features (e.g. maximum mass, surface
temperature, pulsar glitches) can give invaluable information about the exotic
internal microscopic scenario: super-dense, isospin-asymmetric, superfluid,
bulk hadronic matter (probably deconfined in the most central regions) which
can be found nowhere else in the Universe. Indeed, neutrons stars represent a
unique probe to study the properties of the low-temperature, high-density
sector of the QCD phase diagram. Moreover, binary systems of compact stars
allow to make extremely precise measurements of the properties of curved
space-time in the strong field regime, as well as being efficient sources of
gravitational waves.


title:
Modeling and simulation of non-linear and hysteresis behavior of
  magneto-rheological dampers in the example of quarter-car model

abstract:
  This paper presents reviews of several models and numerical simulation models
of non-linear and hysteresis behaviors of magneto-rheological liquid dampers in
MATLAB/Simulink in the example of quarter-car model of vehicle suspension
simulation, such as, Bingham, Dahl, LuGre and Bouc-Wen models. In addition, it
demonstrates numerical simulation models built in MATLAB/Simulink and discusses
results from numerical simulation models for two different input excitations
from terrain.