title:
An LES study of turbulent flow over in-line tube-banks and comparison
  with experimental measurements

abstract:
  Turbulent flow across an in-line array of tube-banks with transverse and
longitudinal pitch PT /D = 2.67, and PL /D = 2.31, has been simulated
successfully by Large Eddy Simulation (LES) based on the dynamic Smagorinsky
subgrid scale model (SGS), in which a wall-layer model is used to reduce the
computational cost. The flow structures across the tube-banks were examined
through the normalized Q criterion. The surface pressure characteristics from
the middle cylinder within each column of cylinders are found to agree well
with the existing experimental data, as did also the values of drag and lift
coefficients. These results indicate that cylinders from the second column
experience the minimum drag force and maximum lift force fluctuation. Spectral
analyses were performed for velocity signals sampled behind each middle
cylinder axis, which show that the dominant vortex shedding frequency does not
vary across the tube-banks. On this basis, we also examined the shear layer
instability. Finally, we report auto-correlation functions for streamwise and
cross velocity fluctuations as a function of the spanwise length.


title:
Kinetic Transition Networks for the Thomson Problem and Smale's 7th
  Problem

abstract:
  The Thomson Problem, arrangement of identical charges on the surface of a
sphere, has found many applications in physics, chemistry and biology. Here we
show that the energy landscape of the Thomson Problem for $N$ particles with
$N=132, 135, 138, 141, 144, 147$ and $150$ is single funnelled, characteristic
of a structure-seeking organisation where the global minimum is easily
accessible. Algorithmically constructing starting points close to the global
minimum of such a potential with spherical constraints is one of Smale's 18
unsolved problems in mathematics for the 21st century because it is important
in the solution of univariate and bivariate random polynomial equations. By
analysing the kinetic transition networks, we show that a randomly chosen
minimum is in fact always `close' to the global minimum in terms of the number
of transition states that separate them, a characteristic of small world
networks.


title: The Lifting Problem is NP Complete

abstract:
  Let $M$ be a 3-manifold. Every knotted (embedded) surface in $M \times \R$
can be moved via an ambient isotopy in such a way that its projection into $M$
is a generic surface. A surface is generic if every point on it is either a
regular, double or triple value - the transversal intersection of 1, 2 or 3
embedded surface sheets, or a "branch value" that look like Whitney's umbrella.
We elaborate on this in Definition 3.1.1. The double values form arcs, and
along each arc two long strips of surface intersect. In a knotted surface, the
additional $\R$ coordinate distinguishes between the two strips. One of them
must be "higher" than the other. We elaborate on this in Definition 3.1.3.
  The lifting problem is the problem of determining if a \gls{genericsurface}
in $M$ can occur as the $M$-projection of a knotted surface in 4-space in $M
\times \R$. The main purpose of this thesis is to study the computational
aspects of the lifting problem. We will prove that the problem is NP-complete,
and devise an efficient algorithm that determines if a generic surface is
liftable.


title:
A Bochner Formula for Harmonic Maps into Non-Positively Curved Metric
  Spaces

abstract:
  We study harmonic maps from Riemannian manifolds into arbitrary
non-positively curved and CAT(-1) metric spaces. First we discuss the domain
variation formula with special emphasis on the error terms. Expanding higher
order terms of this and other formulas in terms of curvature, we prove an
analogue of the Eels-Sampson Bochner formula in this more general setting. In
particular, we show that harmonic maps from spaces of non-negative Ricci
curvature into non-positively curved spaces have subharmonic energy density.
When the domain is compact the energy density is constant, and if the domain
has a point of positive Ricci curvature every harmonic map into an NPC space
must be constant.


title:
Minimal subfamilies and the probabilistic interpretation for modulus on
  graphs

abstract:
  The notion of $p$-modulus of a family of objects on a graph is a measure of
the richness of such families. We develop the notion of minimal subfamilies
using the method of Lagrangian duality for $p$-modulus. We show that minimal
subfamilies have at most $|E|$ elements and that these elements carry a weight
related to their "importance" in relation to the corresponding $p$-modulus
problem. When $p=2$, this measure of importance is in fact a probability
measure and modulus can be thought as trying to minimize the expected overlap
in the family.


title:
Topological surface states interacting with bulk excitations in the
  Kondo insulator SmB$_6$ revealed via planar tunneling spectroscopy

abstract:
  Samarium hexaboride (SmB$_6$), a well-known Kondo insulator in which the
insulating bulk arises from strong electron correlations, has recently
attracted great attention owing to increasing evidence for its topological
nature, thereby harboring protected surface states. However, corroborative
spectroscopic evidence is still lacking, unlike in the weakly correlated
counterparts, including Bi$_2$Se$_3$. Here we report results from planar
tunneling that unveil the detailed spectroscopic properties of SmB$_6$. The
tunneling conductance obtained on the (001) and (011) single crystal surfaces
reveal linear density of states as expected for two and one Dirac cone(s),
respectively. Quite remarkably, it is found that these topological states are
not protected completely within the bulk hybridization gap. A phenomenological
model of the tunneling process invoking interaction of the surface states with
bulk excitations (spin excitons), as predicted by a recent theory, provides a
consistent explanation for all of the observed features. Our spectroscopic
study supports and explains the proposed picture of the incompletely protected
surface states in this topological Kondo insulator SmB$_6$.


title:
Low-Cost Scene Modeling using a Density Function Improves Segmentation
  Performance

abstract:
  We propose a low cost and effective way to combine a free simulation software
and free CAD models for modeling human-object interaction in order to improve
human & object segmentation. It is intended for research scenarios related to
safe human-robot collaboration (SHRC) and interaction (SHRI) in the industrial
domain. The task of human and object modeling has been used for detecting
activity, and for inferring and predicting actions, different from those works,
we do human and object modeling in order to learn interactions in RGB-D data
for improving segmentation. For this purpose, we define a novel density
function to model a three dimensional (3D) scene in a virtual environment
(VREP). This density function takes into account various possible
configurations of human-object and object-object relationships and interactions
governed by their affordances. Using this function, we synthesize a large,
realistic and highly varied synthetic RGB-D dataset that we use for training.
We train a random forest classifier, and the pixelwise predictions obtained is
integrated as a unary term in a pairwise conditional random fields (CRF). Our
evaluation shows that modeling these interactions improves segmentation
performance by ~7\% in mean average precision and recall over state-of-the-art
methods that ignore these interactions in real-world data. Our approach is
computationally efficient, robust and can run real-time on consumer hardware.


title:
On the spontaneous time-reversal symmetry breaking in
  synchronously-pumped passive Kerr resonators

abstract:
  We study the spontaneous temporal symmetry breaking instability in a
coherently-driven passive optical Kerr resonator observed experimentally by Xu
and Coen in Opt.~Lett.~{\bf 39}, 3492 (2014). We perform a detailed stability
analysis of the Lugiato-Lefever model for the optical Kerr resonators and
analyze the temporal bifurcation structure of stationary symmetric and the
emerging asymmetric states as a function of the pump power. For intermediate
pump powers a pitchfork loop is responsible for the destabilization of
symmetric states towards stationary asymmetric ones while at large pump powers
we find the emergence of periodic asymmetric solutions via a Hopf bifurcation.
From a theoretical perspective, we use local bifurcation theory in order to
analyze the most unstable eigenmode of the system. We also explore a
non-conservative variational approximation capturing, among others, the
evolution of the solution's amplitude, width and center of mass. Both methods
provide insight towards the pitchfork bifurcations associated with the symmetry
breaking.


title: Empirical Bayes Estimates for a 2-Way Cross-Classified Additive Model

abstract:
  We develop an empirical Bayes procedure for estimating the cell means in an
unbalanced, two-way additive model with fixed effects. We employ a hierarchical
model, which reflects exchangeability of the effects within treatment and
within block but not necessarily between them, as suggested before by Lindley
and Smith (1972). The hyperparameters of this hierarchical model, instead of
considered fixed, are to be substituted with data-dependent values in such a
way that the point risk of the empirical Bayes estimator is small. Our method
chooses the hyperparameters by minimizing an unbiased risk estimate and is
shown to be asymptotically optimal for the estimation problem defined above.
The usual empirical Best Linear Unbiased Predictor (BLUP) is shown to be
substantially different from the proposed method in the unbalanced case and
therefore performs sub-optimally. Our estimator is implemented through a
computationally tractable algorithm that is scalable to work under large
designs. The case of missing cell observations is treated as well. We
demonstrate the advantages of our method over the BLUP estimator through
simulations and in a real data example, where we estimate average nitrate
levels in water sources based on their locations and the time of the day.


title: Adaptive density estimation based on a mixture of Gammas

abstract:
  We consider the problem of Bayesian density estimation on the positive
semiline for possibly unbounded densities. We propose a hierarchical Bayesian
estimator based on the gamma mixture prior which can be viewed as a location
mixture. We study convergence rates of Bayesian density estimators based on
such mixtures. We construct approximations of the local H\"older densities, and
of their extension to unbounded densities, to be continuous mixtures of gamma
distributions, leading to approximations of such densities by finite mixtures.
These results are then used to derive posterior concentration rates, with
priors based on these mixture models. The rates are minimax (up to a log n
term) and since the priors are independent of the smoothness the rates are
adaptive to the smoothness.


title:
Phonon transport in single-layer Mo1-xWxS2 alloy embedded with WS2
  nanodomains

abstract:
  Two-dimensional (2-D) transition metal dichalcogenides (TMDs) have shown
numerous interesting physical and chemical properties, making them promising
materials for electronic, optoelectronic, and energy applications. Tuning
thermal conductivity of two-dimensional (2-D) materials could expand their
applicability in many of these fields. In this paper, we propose a strategy of
using alloying and nanodomains to suppress the thermal conductivity of 2-D
materials. To predict the thermal conductivity of 2-D alloy embedded with
nanodomains, we employ the Green's function approach to assess the phonon
scattering strength due to alloying and nanodomain embedding. Our
first-principles-driven phonon Boltzmann transport equation calculations show
that the thermal conductivity of single-layer MoS2 can be reduced to less than
one-tenth of its intrinsic thermal conductivity after alloying with W and
introducing nanodomains due to the strong scattering for both high- and
low-frequency phonons. The strategies to further reduce the thermal
conductivity are also discussed.


title:
Measurement Techniques for Thermal Conductivity and Interfacial Thermal
  Conductance of Bulk and Thin Film Materials

abstract:
  Thermal conductivity and interfacial thermal conductance play crucial roles
in the design of engineering systems where temperature and thermal stress are
of concerns. To date, a variety of measurement techniques are available for
both bulk and thin film solid-state materials with a broad temperature range.
For thermal characterization of bulk material, the steady-state absolute
method, laser flash diffusivity method, and transient plane source method are
most used. For thin film measurement, the 3{\omega} method and transient
thermoreflectance technique including both frequency-domain and time-domain
analysis are employed widely. This work reviews several most commonly used
measurement techniques. In general, it is a very challenging task to determine
thermal conductivity and interface contact resistance with less than 5% error.
Selecting a specific measurement technique to characterize thermal properties
need to be based on: 1) knowledge on the sample whose thermophysical properties
is to be determined, including the sample geometry and size, and preparation
method; 2) understanding of fundamentals and procedures of the testing
technique and equipment, for example, some techniques are limited to samples
with specific geometrics and some are limited to specific range of
thermophysical properties; 3) understanding of the potential error sources
which might affect the final results, for example, the convection and radiation
heat losses.


title: A Feature based Approach for Video Compression

abstract:
  It is a high cost problem for panoramic image stitching via image matching
algorithm and not practical for real-time performance. In this paper, we take
full advantage ofHarris corner invariant characterization method light
intensity parallel meaning, translation and rotation, and made a realtime
panoramic image stitching algorithm. According to the basic characteristics and
performance FPGA classical algorithm, several modules such as the feature point
extraction, and matching description is to optimize the feature-based logic.
Real-time optimization system to achieve high precision match. The new
algorithm process the image from pixel domain and obtained from CCD camera
Xilinx Spartan-6 hardware platform. After the image stitching algorithm, will
eventually form a portable interface to output high-definition content on the
display. The results showed that, the proposed algorithm has higher precision
with good real-time performance and robustness.


title:
Do planetary seasons play a fundamental role in attaining habitable
  climates?

abstract:
  A simple phenomenological account for planetary climate instabilities is
presented. The description is based on the standard model where the balance of
incoming stellar radiation and outward thermal radiation is described by the
effective planet temperature. Often, it is found to have three different
points, or temperatures, where the influx of radiation is balanced with the
out-flux, even with conserved boundary conditions. Two of these points are
relatively long-term stable, namely the point corresponding to a frozen-climate
and the point corresponding to a hot-climate. The hypothesis promoted in this
paper is the possibility that it is the intermediate third point which is the
basis for habitable-climates. I.e. that this initially unstable point is made
relatively stable over a long period by the presence of seasonal climate
variations. This points to the axial inclination, and perhaps the presence of
orbital eccentricity, as the origin of the stability of the habitable point. An
analysis involving the inclination, the size of the ice caps, and the length of
the year shows that within the currently accepted value of the heat capacity of
the Earth, the otherwise unstable habitable point is stabilized.


title: Strong Lensing In The Inner Halo Of Galaxy Clusters

abstract:
  We present an axially symmetric formula to calculate the probability of
finding gravitational arcs in galaxy clusters, being induced by their massive
dark matter haloes, as a function of clusters redshifts and virial masses. The
formula includes the ellipticity of the clusters dark matter potential by using
a pseudo-elliptical approximation. The probabilities are calculated and
compared for two dark-matter halo profiles, the Navarro, Frenk and White (NFW)
and the Non-Singular-Isothermal-Sphere (NSIS). We demonstrate the power of our
formulation through a Kolmogorov-Smirnov (KS) test on the strong lensing
statistics of an X-ray bright sample of low redshift Abell clusters. This KS
test allows to establish limits on the values of the concentration parameter
for the NFW profile ($c_\Delta$) and the core radius for the NSIS profile
(\rc), which are related to the lowest cluster redshift ($z_{\rm cut}$) where
strong arcs can be observed. For NFW dark matter profiles, we infer cluster
haloes with concentrations that are consistent to those predicted by
$\Lambda$CDM simulations. As for NSIS dark matter profiles, we find only upper
limits for the clusters core radii and thus do not rule out a purely SIS model.
For alternative mass profiles, our formulation provides constraints through
$z_{\rm cut}$ on the parameters that control the concentration of mass in the
inner region of the clusters haloes. We find that $z_{\rm cut}$ is expected to
lie in the 0.0--0.2 redshift, highlighting the need to include very low-$z$
clusters in samples to study the clusters mass profiles.


title: Robust designs for experiments with blocks

abstract:
  For experiments running in field plots or over time, the observations are
often correlated due to spatial or serial correlation, which leads to
correlated errors in a linear model analyzing the treatment means. Without
knowing the exact correlation matrix of the errors, it is not possible to
compute the generalized least squares estimator for the treatment means and use
it to construct optimal designs for the experiments. In this paper we propose
to use neighbourhoods to model the covariance matrix of the errors, and apply a
modified generalized least squares estimator to construct robust designs for
experiments with blocks. A minimax design criterion is investigated, and a
simulated annealing algorithm is developed to find robust designs. We have
derived several theoretical results, and representative examples are presented.


title: Dynamics of transcription-translation networks

abstract:
  A theory for qualitative models of gene regulatory networks has been
developed over several decades, generally considering transcription factors to
regulate directly the expression of other transcription factors, without any
intermediate variables. Here we explore a class of models that explicitly
includes both transcription and translation, keeping track of both mRNA and
protein concentrations. We mainly deal with transcription regulation functions
that are steep sigmoids or step functions, as is often done in protein-only
models, though translation is governed by a linear term. We extend many aspects
of the protein-only theory to this new context, including properties of fixed
points, description of trajectories by mappings between switching points,
qualitative analysis via a state-transition diagram, and a result on periodic
orbits for negative feedback loops. We find that while singular behaviour in
switching domains is largely avoided, non-uniqueness of solutions can still
occur in the step-function limit.


title:
Toward an Energy Efficient Language and Compiler for (Partially)
  Reversible Algorithms

abstract:
  We introduce a new programming language for expressing reversibility,
Energy-Efficient Language (Eel), geared toward algorithm design and
implementation. Eel is the first language to take advantage of a partially
reversible computation model, where programs can be composed of both reversible
and irreversible operations. In this model, irreversible operations cost energy
for every bit of information created or destroyed. To handle programs of
varying degrees of reversibility, Eel supports a log stack to automatically
trade energy costs for space costs, and introduces many powerful control logic
operators including protected conditional, general conditional, protected
loops, and general loops. In this paper, we present the design and compiler for
the three language levels of Eel along with an interpreter to simulate and
annotate incurred energy costs of a program.


title:
Variational Approach to studying solitary waves in the nonlinear
  Schrodinger equation with Complex Potentials

abstract:
  We discuss the behavior of solitary wave solutions of the nonlinear
Schr{\"o}dinger equation (NLSE) as they interact with complex potentials, using
a four parameter variational approximation based on a dissipation functional
formulation of the dynamics. We concentrate on spatially periodic potentials
with the periods of the real and imaginary part being either the same or
different. Our results for the time evolution of the collective coordinates of
our variational ansatz are in good agreement with direct numerical simulation
of the NLSE. We compare our method with a collective coordinate approach of
Kominis and give examples where the two methods give qualitatively different
answers. In our variational approach, we are able to give analytic results for
the small oscillation frequency of the solitary wave oscillating parameters
which agree with the numerical solution of the collective coordinate equations.
We also verify that instabilities set in when the slope of $dp(t)/dv(t)$
becomes negative when plotted parametrically as a function of time, where
$p(t)$ is the momentum of the solitary wave and $v(t)$ the velocity.


title: Spatial Mode Selective Waveguide with Hyperbolic Cladding

abstract:
  Hyperbolic Meta-Materials~(HMMs) are anisotropic materials with permittivity
tensor that has both positive and negative eigenvalues. Here we report that by
using a type II HMM as cladding material, a waveguide which only supports
higher order modes can be achieved, while the lower order modes become leaky
and are absorbed in the HMM cladding. This counter intuitive property can lead
to novel application in optical communication and photonic integrated circuit.
The loss in our HMM-Insulator-HMM~(HIH) waveguide is smaller than that of
similar guided mode in a Metal-Insulator-Metal~(MIM) waveguide.


title: Model-Free Imitation Learning with Policy Optimization

abstract:
  In imitation learning, an agent learns how to behave in an environment with
an unknown cost function by mimicking expert demonstrations. Existing imitation
learning algorithms typically involve solving a sequence of planning or
reinforcement learning problems. Such algorithms are therefore not directly
applicable to large, high-dimensional environments, and their performance can
significantly degrade if the planning problems are not solved to optimality.
Under the apprenticeship learning formalism, we develop alternative model-free
algorithms for finding a parameterized stochastic policy that performs at least
as well as an expert policy on an unknown cost function, based on sample
trajectories from the expert. Our approach, based on policy gradients, scales
to large continuous environments with guaranteed convergence to local minima.


title:
Evaluating the paleomagnetic potential of single zircon crystals using
  the Bishop Tuff

abstract:
  Zircon crystals offer a unique combination of suitability for high-precision
radiometric dating and high resistance to alteration. Paleomagnetic experiments
on ancient zircons may potentially constrain the earliest geodynamo, which
holds broad implications for the early Earth interior and atmosphere. However,
the ability of zircons to record accurately the geomagnetic field has not been
fully demonstrated. Here we conduct thermal and room temperature alternating
field (AF) paleointensity experiments on 767.1 thousand year old (ka) zircons
from the Bishop Tuff, California. The rapid emplacement of these zircons in a
well-characterized magnetic field provides a high-fidelity test of the zircons
intrinsic paleomagnetic recording accuracy. Successful dual heating experiments
on nine zircons measured using a superconducting quantum interference device
(SQUID) microscope yield a mean paleointensity of 46.2 +/- 18.8 microtesla
(1sigma), which agrees closely with high-precision results from Bishop Tuff
whole rock (43.0 +/- 3.2 microtesla). High-resolution quantum diamond magnetic
mapping, electron microscopy, and X-ray tomography indicate that the bulk of
the remanent magnetization in Bishop Tuff zircons is carried by Fe oxides
associated with apatite inclusions, which would be susceptible to destruction
via metamorphism and aqueous alteration in older zircons. As such, while
zircons can reliably record the geomagnetic field, robust zircon-derived
paleomagnetic results require careful characterization of the ferromagnetic
carrier and demonstration of their occurrence in primary inclusions. We further
conclude that a combination of quantum diamond magnetometry and high-resolution
imaging can provide detailed, direct characterization of the ferromagnetic
mineralogy of geological samples.


title:
Coherent and Incoherent Coupling Dynamics between Neutral and Charged
  Excitons in Monolayer MoSe2

abstract:
  The optical properties of semiconducting transition metal dichalcogenides are
dominated by both neutral excitons (electron-hole pairs) and charged excitons
(trions) that are stable even at room temperature. While trions directly
influence charge transport properties in optoelectronic devices, excitons may
be relevant through exciton-trion coupling and conversion phenomena. In this
work, we reveal the coherent and incoherent nature of exciton-trion coupling
and the relevant timescales in monolayer MoSe2 using optical two-dimensional
coherent spectroscopy. Coherent interaction between excitons and trions is
definitively identified as quantum beating of cross-coupling peaks that
persists for a few hundred femtoseconds. For longer times up to 10 ps,
surprisingly, the relative intensity of the cross-coupling peaks increases,
which is attributed to incoherent energy transfer likely due to phonon-assisted
up-conversion and down-conversion processes that are efficient even at
cryogenic temperature.


title:
Open Problem: Best Arm Identification: Almost Instance-Wise Optimality
  and the Gap Entropy Conjecture

abstract:
  The best arm identification problem (BEST-1-ARM) is the most basic pure
exploration problem in stochastic multi-armed bandits. The problem has a long
history and attracted significant attention for the last decade. However, we do
not yet have a complete understanding of the optimal sample complexity of the
problem: The state-of-the-art algorithms achieve a sample complexity of
$O(\sum_{i=2}^{n} \Delta_{i}^{-2}(\ln\delta^{-1} + \ln\ln\Delta_i^{-1}))$
($\Delta_{i}$ is the difference between the largest mean and the $i^{th}$
mean), while the best known lower bound is $\Omega(\sum_{i=2}^{n}
\Delta_{i}^{-2}\ln\delta^{-1})$ for general instances and $\Omega(\Delta^{-2}
\ln\ln \Delta^{-1})$ for the two-arm instances. We propose to study the
instance-wise optimality for the BEST-1-ARM problem. Previous work has proved
that it is impossible to have an instance optimal algorithm for the 2-arm
problem. However, we conjecture that modulo the additive term
$\Omega(\Delta_2^{-2} \ln\ln \Delta_2^{-1})$ (which is an upper bound and worst
case lower bound for the 2-arm problem), there is an instance optimal algorithm
for BEST-1-ARM. Moreover, we introduce a new quantity, called the gap entropy
for a best-arm problem instance, and conjecture that it is the instance-wise
lower bound. Hence, resolving this conjecture would provide a final answer to
the old and basic problem.


title:
Electric dipole response of neutron-rich Calcium isotopes in
  relativistic quasiparticle time blocking approximation

abstract:
  New results for electric dipole strength in the chain of even-even Calcium
isotopes with the mass numbers A = 40 - 54 are presented. Starting from the
covariant Lagrangian of Quantum Hadrodynamics, spectra of collective vibrations
(phonons) and phonon-nucleon coupling vertices for $J \leq 6$ and normal parity
were computed in a self-consistent relativistic quasiparticle random phase
approximation (RQRPA). These vibrations coupled to Bogoliubov two-quasiparticle
configurations (2q$\otimes$phonon) form the model space for the calculations of
the dipole response function in the relativistic quasiparticle time blocking
approximation (RQTBA). The results for giant dipole resonance in the latter
approach are compared to those obtained in RQRPA and to available data.
Evolution of the dipole strength with neutron number is investigated for both
high-frequency giant dipole resonance (GDR) and low-lying strength. Development
of a pygmy resonant structure on the low-energy shoulder of GDR is traced and
analyzed in terms of transition densities. A dependence of the pygmy dipole
strength on the isospin asymmetry parameter is extracted.


title:
Did the Crab Pulsar Undergo a Small Glitch in 2006 late March/early
  April?

abstract:
  On 2006 August 23 the Crab Pulsar underwent a glitch, that was reported by
the Jodrell Bank and the Xinjiang radio observatories. Neither data are
available to the public. However, the Jodrell group publishes monthly arrival
times of the Crab Pulsar pulse (their actual observations are done daily),
using which it is shown that about five months earlier, the Crab Pulsar most
probably underwent a small glitch, which has not been reported before. Neither
observatory discusses the detailed analysis of data from 2006 March to August;
either they may not have detected this small glitch, or may have attributed it
to timing noise in the Crab Pulsar. The above result is verified using X-ray
data from the RXTE observatory. If this is indeed true, this may probably be
the smallest glitch observed in the Crab Pulsar so far, whose implications are
discussed. This work addresses the confusion possible between small magnitude
glitches and timing noise in pulsars.


title:
Networks of Gratitude: Structures of Thanks and User Expectations in
  Workplace Appreciation Systems

abstract:
  Appreciation systems--platforms for users to exchange thanks and praise--are
becoming common in the workplace, where employees share appreciation, managers
are notified, and aggregate scores are sometimes made visible. Who do people
thank on these systems, and what do they expect from each other and their
managers? After introducing the design affordances of 13 appreciation systems,
we discuss a system we call Gratia, in use at a large multinational company for
over four years. Using logs of 422,000 appreciation messages and user surveys,
we explore the social dynamics of use and ask if use of the system addresses
the recognition problem. We find that while thanks is mostly exchanged among
employees at the same level and different parts of the company, addressing the
recognition problem, managers do not always act on that recognition in ways
that employees expect.


title: The State of the Art in Cartograms

abstract:
  Cartograms combine statistical and geographical information in thematic maps,
where areas of geographical regions (e.g., countries, states) are scaled in
proportion to some statistic (e.g., population, income). Cartograms make it
possible to gain insight into patterns and trends in the world around us and
have been very popular visualizations for geo-referenced data for over a
century. This work surveys cartogram research in visualization, cartography and
geometry, covering a broad spectrum of different cartogram types: from the
traditional rectangular and table cartograms, to Dorling and diffusion
cartograms. A particular focus is the study of the major cartogram dimensions:
statistical accuracy, geographical accuracy, and topological accuracy. We
review the history of cartograms, describe the algorithms for generating them,
and consider task taxonomies. We also review quantitative and qualitative
evaluations, and we use these to arrive at design guidelines and research
challenges.


title: Mixtape Application: Last.fm Data Characterization

abstract:
  This report analyses data collected from Last.fm and used to create a
real-time recommendation system. We collected over 2M songs and 1M tags and
372K user's listening habits. We characterize users' profiles: age, playcount,
friends, gender and country. We characterized song, artist and tag popularity,
genres of songs. Additionally we evaluated the co-occurrence of songs in users'
histories, which can be used to compute similarity between songs.


title: On The 2D Phase Retrieval Problem

abstract:
  The recovery of a signal from the magnitude of its Fourier transform, also
known as phase retrieval, is of fundamental importance in many scientific
fields. It is well known that due to the loss of Fourier phase the problem in
1D is ill-posed. Without further constraints, there is no unique solution to
the problem. In contrast, uniqueness up to trivial ambiguities very often
exists in higher dimensions, with mild constraints on the input. In this paper
we focus on the 2D phase retrieval problem and provide insight into this
uniqueness property by exploring the connection between the 2D and 1D
formulations. In particular, we show that 2D phase retrieval can be cast as a
1D problem with additional constraints, which limit the solution space. We then
prove that only one additional constraint is sufficient to reduce the many
feasible solutions in the 1D setting to a unique solution for almost all
signals. These results allow to obtain an analytical approach (with
combinatorial complexity) to solve the 2D phase retrieval problem when it is
unique.


title: Gamma-ray-emitting quasar 0202$+$149: a CSS revisited

abstract:
  PKS 0202$+$149 is a low-power radio source with blazar-like $\gamma$-ray AGN
characteristics and its properties and classification are investigated in
relation to its $\gamma$-ray characteristics. It shows a hint of low frequency
turnover at about 200 MHz. Radio imaging data of 0202$+$149 at different
frequencies show differing morphologies on both kilo-parsec (kpc) and parsec
(pc) scales. The overall source shows a triple structure of core and double
lobes with a total projected size of $\sim$1.3 kpc. The compact source
structure of 0202+149 is reminiscent of a compact steep spectrum (CSS) source.
At pc scales a core-jet structure extends $\sim$25 pc (in projection) at a
position angle perpendicular to the kpc-scale structure. The curved pc-scale
structure with jet and inner lobe suggests that the CSS nuclear activity has
recently re-started although its power has been decreasing, while the kpc-scale
lobes are relics of earlier activity. A maximum apparent superluminal motion of
$\sim16\,c$ is detected in the jet components, indicating a highly relativistic
jet flow. The brightness temperature of the core is lower than the average
value found for highly-beamed $\gamma$-ray AGN, indicating a lower radio power
and a relatively lower Doppler boosting factor. The CSS radio classification
indicates that blazar-like $\gamma$-ray properties can also be manifested in
low-power CSS radio sources with appropriate jet and beaming properties.


title: The Primary Design of the Ridgetron

abstract:
  The ridgetron is used to accelerate the intense beam for the electron
irradiation. According to the electromagnetic field simulation, the extend
electrode should be cancelled to increase the shunt impedence. The method of
parameter sweeping with constraint variables (PSCV) is used to scan the
mechanical parameters of the cavity to optimize the shunt impedence. The
thermal analysis also has been done for water cooling. The beam dynamic
simulation has been done at last.


title: A Simple and Strongly-Local Flow-Based Method for Cut Improvement

abstract:
  Many graph-based learning problems can be cast as finding a good set of
vertices nearby a seed set, and a powerful methodology for these problems is
based on maximum flows. We introduce and analyze a new method for
locally-biased graph-based learning called SimpleLocal, which finds good
conductance cuts near a set of seed vertices. An important feature of our
algorithm is that it is strongly-local, meaning it does not need to explore the
entire graph to find cuts that are locally optimal. This method solves the same
objective as existing strongly-local flow-based methods, but it enables a
simple implementation. We also show how it achieves localization through an
implicit L1-norm penalty term. As a flow-based method, our algorithm exhibits
several ad- vantages in terms of cut optimality and accurate identification of
target regions in a graph. We demonstrate the power of SimpleLocal by solving
problems on a 467 million edge graph based on an MRI scan.


title: Provable Algorithms for Inference in Topic Models

abstract:
  Recently, there has been considerable progress on designing algorithms with
provable guarantees -- typically using linear algebraic methods -- for
parameter learning in latent variable models. But designing provable algorithms
for inference has proven to be more challenging. Here we take a first step
towards provable inference in topic models. We leverage a property of topic
models that enables us to construct simple linear estimators for the unknown
topic proportions that have small variance, and consequently can work with
short documents. Our estimators also correspond to finding an estimate around
which the posterior is well-concentrated. We show lower bounds that for shorter
documents it can be information theoretically impossible to find the hidden
topics. Finally, we give empirical results that demonstrate that our algorithm
works on realistic topic models. It yields good solutions on synthetic data and
runs in time comparable to a {\em single} iteration of Gibbs sampling.


title: Tracing the Attention of Moving Citizens

abstract:
  With the widespread use of mobile computing devices in contemporary society,
our trajectories in the physical space and virtual world are increasingly
closely connected. Using the anonymous smartphone data of $1 \times 10^5$ users
in 30 days, we constructed the mobility network and the attention network to
study the correlations between online and offline human behaviours. In the
mobility network, nodes are physical locations and edges represent the
movements between locations, and in the attention network, nodes are websites
and edges represent the switch of users between websites. We apply the
box-covering method to renormalise the networks. The investigated network
properties include the size of box $l_B$ and the number of boxes $N(l_B)$. We
find two universal classes of behaviours: the mobility network is featured by a
small-world property, $N(l_B) \simeq e^{-l_B}$, whereas the attention network
is characterised by a self-similar property $N(l_B) \simeq l_B^{-\gamma}$. In
particular, with the increasing of the length of box $l_B$, the degree
correlation of the network changes from positive to negative which indicates
that there are two layers of structure in the mobility network. We use the
results of network renormalisation to detect the community and map the
structure of the mobility network. Further, we located the most relevant
websites visited in these communities, and identified three typical
location-based behaviours, including the shopping, dating, and taxi-calling.
Finally, we offered a revised geometric network model to explain our findings
in the perspective of spatial-constrained attachment.


title:
Quantum Locality, Rings a Bell?: Bell's inequality meets local reality
  and true determinism

abstract:
  By assuming a deterministic evolution of quantum systems and taking realism
into account, we carefully build a hidden variable theory for Quantum Mechanics
based on the notion of ontological states proposed by 't Hooft. We view these
ontological states as the ones embedded with realism and compare them to the
(usual) quantum states that represent superpositions, viewing the latter as
mere information of the system they describe. Such a deterministic model puts
forward conditions for the applicability of Bell's inequality: the usual
inequality cannot be applied to the usual experiments. We build a Bell-like
inequality that can be applied to the EPR scenario and show that this
inequality is always satisfied by Quantum Mechanics. In this way we show that
Quantum Mechanics can indeed have a local interpretation, and thus meet with
the causal structure imposed by the Theory of Special Relativity in a
satisfying way.


title: Mixtape Application: Music Map Methodology and Evaluation

abstract:
  This report discusses dimensionality reduction techniques used to create a
music map - a map where the distances between songs represent their similarity
and that can be used to recommend songs. We evaluate two techniques: Isomap and
L-Isomap.


title: Matched witness for multipartite entanglement

abstract:
  We transform the way of finding entanglement criterion into two steps: to
obtain necessary criterion of separability by maximizing an algebra function
for a set of characteristic variables of the witness operator and the given
number of partitions, then to obtain the sufficient criterion by minimizing an
algebra function with respect to the characteristic variables for a given
quantum state. Our method avoids the semi-definite program calculation in the
witness operator entanglement detection. The necessary and sufficient criterion
of separability for the three qubit X shaped state is given to illustrate the
procedure of finding the criterion. We give the necessary and sufficient
criteria of the three partite and full separabilities for the four qubit noisy
GHZ state and the four qubit noisy cluster state.


title:
Necessary and sufficient criterion for k-separability of N-qubit noisy
  GHZ states

abstract:
  A Multipartite entangled state has many different kinds of entanglement
specified by the number of partitions. The most essential example of
multipartite entanglement is the entanglement of multi-qubit
Greenberger-Horne-Zeilinger (GHZ) state in white noise. We explicitly construct
the entanglement witnesses for these states with stabilizer generators of the
GHZ states. For a $N$ qubit GHZ state in white noise, we demonstrate the
necessary and sufficient criterion of separability when it is divided into $k$
parties with $N\leq 2k-1$ for arbitrary $N$ and $k$. The criterion covers more
than a half of all kinds of partial entanglement for $% N $-qubit GHZ states in
white noise. For the rest of multipartite entanglement problems, we present a
method to obtain the sufficient conditions of separability. As an application,
we consider $N$ qubit GHZ state as a codeword of the degenerate quantum code
passing through depolarizing channel. We find that the output state is neither
genuinely entangled nor fully separable when the quantum channel capacity
reduces from positive to zero.


title: Universum Learning for SVM Regression

abstract:
  This paper extends the idea of Universum learning [18, 19] to regression
problems. We propose new Universum-SVM formulation for regression problems that
incorporates a priori knowledge in the form of additional data samples. These
additional data samples or Universum belong to the same application domain as
the training samples, but they follow a different distribution. Several
empirical comparisons are presented to illustrate the utility of the proposed
approach.


title: Correlation Functions of Sp(2n) Invariant Higher-Spin Systems

abstract:
  We study the general structure of correlation functions in an
Sp(2n)-invariant formulation of systems of an infinite number of higher-spin
fields. For n=4,8 and 16 these systems comprise the conformal higher-spin
fields in space-time dimensions D=4,6 and 10, respectively, while when n=2, one
deals with conventional D=3 conformal field theories of scalars and spinors. We
show that for n>2 the Sp(2n) symmetry and current conservation makes the
3-point correlators of two (rank-one or rank-two) conserved currents with a
scalar operator be that of free theory.This situation is analogous to the one
in conventional conformal field theories, where conservation of higher-spin
currents implies that the theories are free.


title:
Evaluation of Coded Aperture Radiation Detectors using a Bayesian
  Approach

abstract:
  We investigate the utility of coded aperture (CA) for roadside radiation
threat detection applications. With coded aperture, information in the form of
photon quantity is traded for directional information. Whether and in what
scenarios this trade-off is beneficial is the focus of this study. We quantify
the impact of a masking approach by comparing performance with an unmasked
approach in terms of both detection and localization of a roadside nuclear
threat. We measure performance over many instances of a drive-by scenario via
Monte Carlo simulation based on empirical observations.


title: Generalized Morrey spaces and trace operator

abstract:
  The theory of generalized Besov-Morrey spaces and generalized
Triebel-Lizorkin-Morrey spaces is developed. Generalized Morrey spaces, which
T. Mizuhara and E. Nakai proposed, are equipped with a parameter and a
function. The trace property is one of the main focuses of the present paper,
which will clarify the role of the parameter of generalized Morrey spaces. The
quarkonial decomposition is obtained as an application of atomic decomposition.
In the end, the relation between the function spaces dealt in the present paper
and the foregoing researches is discussed.


title: Local Region Sparse Learning for Image-on-Scalar Regression

abstract:
  Identification of regions of interest (ROI) associated with certain disease
has a great impact on public health. Imposing sparsity of pixel values and
extracting active regions simultaneously greatly complicate the image analysis.
We address these challenges by introducing a novel region-selection penalty in
the framework of image-on-scalar regression. Our penalty combines the Smoothly
Clipped Absolute Deviation (SCAD) regularization, enforcing sparsity, and the
SCAD of total variation (TV) regularization, enforcing spatial contiguity, into
one group, which segments contiguous spatial regions against zero-valued
background. Efficient algorithm is based on the alternative direction method of
multipliers (ADMM) which decomposes the non-convex problem into two iterative
optimization problems with explicit solutions. Another virtue of the proposed
method is that a divide and conquer learning algorithm is developed, thereby
allowing scaling to large images. Several examples are presented and the
experimental results are compared with other state-of-the-art approaches.


title: Gravitational Quasinormal Modes of Regular Phantom Black Hole

abstract:
  We investigate the gravitational quasi-normal modes (QNMs) for a type of
regular black hole (BH) known as phantom BH, which is a static self-gravitating
solution of a minimally coupled phantom scalar field with a potential. The
studies are carried out for three different spacetimes: asymptotically flat, de
Sitter (dS), and anti de Sitter (AdS). In order to consider the standard odd
parity and even parity of gravitational perturbations, the corresponding master
equations are derived. The QNMs are discussed by evaluating the temporal
evolution of the perturbation field which, in turn, provides direct information
on the stability of BH spacetime. It is found that in asymptotically flat, dS
and AdS spacetimes, the gravitational perturbations have similar
characteristics for both odd and even parities. The decay rate of perturbation
is strongly dependent on the scale parameter $b$, which measures the coupling
strength between phantom scalar field and the gravity. Furthermore, through the
analysis of Hawking radiation, it is shown that the thermodynamics of such
regular phantom BH is also influenced by $b$. The obtained results might shed
some light on the quantum interpretation of QNM perturbation.


title:
Pipeline Implementations of Neumann-Neumann and Dirichlet-Neumann
  Waveform Relaxation Methods

abstract:
  This paper is concerned with the reformulation of Neumann-Neumann Waveform
Relaxation (NNWR) methods and Dirichlet-Neumann Waveform Relaxation (DNWR)
methods, a family of parallel space-time approaches to solving time-dependent
PDEs. By changing the order of the operations, pipeline-parallel computation of
the waveform iterates are possible without changing the final solution. The
parallel efficiency and the increased communication cost of the pipeline
implementation is presented, along with weak scaling studies to show the
effectiveness of the pipeline NNWR and DNWR algorithms.


title: Multiply Phased Traveling BPS Vortex

abstract:
  We present the multiply phased current carrying vortex solutions in the U(1)
gauge theory coupled to an $(N+1)$-component SU(N+1) scalar multiplet in the
Bogomolny limit. Our vortex solutions correspond to the static vortex dressed
with traveling waves along the axis of symmetry. What is notable in our vortex
solutions is that the frequencies of traveling waves in each component of the
scalar field can have different values. The energy of the static vortex is
proportional to the topological charge of $CP^N$ model in the BPS limit, and
the multiple phase of the vortex supplies additional energy contribution which
is proportional to the Noether charge associated to the remaining symmetry.


title: Spin-Hall effect and circular birefringence of a uniaxial crystal plate

abstract:
  The linear birefringence of uniaxial crystal plates is known since the 17th
century, and it is widely used in numerous optical setups and devices. Here we
demonstrate, both theoretically and experimentally, a fine lateral circular
birefringence of such crystal plates. This effect is a novel example of the
spin-Hall effect of light, i.e., a transverse spin-dependent shift of the
paraxial light beam transmitted through the plate. The well-known linear
birefringence and the new circular birefringence form an interesting analogy
with the Goos-H\"anchen and Imbert-Fedorov beam shifts that appear in the light
reflection at a dielectric interface. We report the experimental observation of
the effect in a remarkably simple system of a tilted half-wave plate and
polarizers using polarimetric and quantum-weak-measurement techniques for the
beam-shift measurements. In view of great recent interest in spin-orbit
interaction phenomena, our results could find applications in modern
polarization optics and nano-photonics.


title: Generalized concurrence in boson sampling

abstract:
  A fundamental question in linear optical quantum computing is to understand
the origin of the quantum supremacy in the physical system. It is found that
the multimode linear optical transition amplitudes are calculated through the
permanents of transition operator matrices, which is a hard problem for
classical simulations (boson sampling problem). We can understand this problem
by considering a quantum measure that directly determines the runtime for
computing the transition amplitudes. In this paper, we suggest a quantum
measure named "Fock state concurrence sum" $C_S$, which is the summation over
all the members of "the generalized Fock state concurrence" (a measure
analogous to the generalized concurrences of entanglement and coherence). By
introducing generalized algorithms for computing the transition amplitudes of
the Fock state boson sampling with an arbitrary number of photons per mode, we
show that the minimal classical runtime for all the known algorithms directly
depends on $C_S$. Therefore, we can state that \emph{the Fock state concurrence
sum $C_S$ behaves as a collective measure that controls the computational
complexity of Fock state BS}. We expect that our observation on the role of the
Fock state concurrence in the generalized algorithm for permanents would
provide a unified viewpoint to interpret the quantum computing power of linear
optics.


title: "Dancing with the stars" - astronomy and music in the Torres Strait

abstract:
  Song and dance are a traditional means of strengthening culture and passing
knowledge to successive generations in the Torres Strait of northeastern
Australia. Dances incorporate a range of apparatuses to enhance the
performance, such as dance machines (Zamiyakal) and headdresses (Dhari). The
dances, songs, headdresses and dance machines work together to transfer
important knowledge about subsistence survival, social structure, and cultural
continuity. This paper explores how celestial phenomena inspire and inform
music and dance.


title: Spectroscopic factor strengths using $ab ~ initio$ approaches

abstract:
  We have calculated the spectroscopic factor strengths for the one-proton and
one-neutron pick-up reactions $^{27}$Al($d$,$^{3}$He)$^{26}$Mg and
$^{27}$Al($d$,$t$)$^{26}$Al within the framework of the shell model. We
employed two different $ab ~ initio$ approaches : an in-medium similarity
renormalization targeted for a particular nucleus, and the coupled- cluster
effective interaction. We also compared our results with recently determined
experimental spectroscopic factors.


title:
Restriction Theorem for Oscillatory Integral Operator with Certain
  Polynomial Phase

abstract:
  We consider the following oscillatory integral operator
\begin{equation}\label{opera-defi-1}
  T_{\alpha,m}f(x)=\int_{\mathbb R^n}e^{i(x_1^{\alpha_1}
y_1^m+\cdots+x_n^{\alpha_n} y_n^m)}f(y)dy, \end{equation} where the function
$f$ is a Schwartz function. In this paper, the restriction theorem on
$\mathbb{S}^{n-1}$ for this operator is obtained. Moreover, we obtain a
necessary condition which ensures the restriction theorem hold.


title:
Bounded orbits of certain diagonalizable flows on
  $SL_{n}(\mathbb{R})/SL_{n}(\mathbb{Z})$

abstract:
  We prove that the set of points that have bounded orbits under certain
diagonalizable flows is a hyperplane absolute winning subset of
$SL_{n}(\mathbb{R})/SL_{n}(\mathbb{Z})$.


title:
Convergence of the Z-Bus Method for Three-Phase Distribution Load-Flow
  with ZIP Loads

abstract:
  This paper derives a set of sufficient conditions guaranteeing that the
load-flow problem in unbalanced three-phase distribution networks with wye and
delta ZIP loads has a unique solution over a region that can be explicitly
calculated from the network parameters. It is also proved that the well-known
Z-Bus iterative method is a contraction over the defined region, and hence
converges to the unique solution.


title: SNN: Stacked Neural Networks

abstract:
  It has been proven that transfer learning provides an easy way to achieve
state-of-the-art accuracies on several vision tasks by training a simple
classifier on top of features obtained from pre-trained neural networks. The
goal of this work is to generate better features for transfer learning from
multiple publicly available pre-trained neural networks. To this end, we
propose a novel architecture called Stacked Neural Networks which leverages the
fast training time of transfer learning while simultaneously being much more
accurate. We show that using a stacked NN architecture can result in up to 8%
improvements in accuracy over state-of-the-art techniques using only one
pre-trained network for transfer learning. A second aim of this work is to make
network fine- tuning retain the generalizability of the base network to unseen
tasks. To this end, we propose a new technique called "joint fine-tuning" that
is able to give accuracies comparable to finetuning the same network
individually over two datasets. We also show that a jointly finetuned network
generalizes better to unseen tasks when compared to a network finetuned over a
single task.


title:
Stochastic Online Control for Energy-Harvesting Wireless Networks with
  Battery Imperfections

abstract:
  In energy harvesting (EH) network, the energy storage devices (i.e.,
batteries) are usually not perfect. In this paper, we consider a practical
battery model with finite battery capacity, energy (dis-)charging loss, and
energy dissipation. Taking into account such battery imperfections, we rely on
the Lyapunov optimization technique to develop a stochastic online control
scheme that aims to maximize the utility of data rates for EH multi-hop
wireless networks. It is established that the proposed algorithm can provide a
feasible and efficient data admission, power allocation, routing and scheduling
solution, without requiring any statistical knowledge of the stochastic
channel, data-traffic, and EH processes. Numerical results demonstrate the
merit of the proposed scheme.


title:
Competition between disorder and Coulomb interaction in a
  two-dimensional plaquette Hubbard model

abstract:
  We have studied a disordered $N_{\rm c} \times N_{\rm c}$ plaquette Hubbard
model on a two-dimensional square lattice at half-filling using a coherent
potential approximation (CPA) in combination with a single-site dynamical mean
field theory (DMFT) approach with a paramagnetic bath. Such a model
conveniently interpolates between the ionic Hubbard model at $N_{\rm
c}=\sqrt{2}$ and the Anderson model at $N_{\rm c} = \infty$ and enables the
analysis of the various limiting properties. We confirmed that within the CPA
approach a band insulator behavior appears for non-interacting strongly
disordered systems with a small plaquette size $N_{\rm c} = 4$, while the
paramagnetic Anderson insulator with nearly gapless density of states is
present for large plaquette sizes $N_{\rm c}=48$. When the interaction $U$ is
turned on in the strongly fluctuating random potential regions, the electrons
on the low energy states push each other into high energy states in DMFT in a
paramagnetic bath and correlated metallic states with a quasiparticle peak and
Hubbard bands emerge, though a larger critical interaction $U$ is needed to
obtain this state from the paramagnetic Anderson insulator ($N_{\rm c}=48$)
than from the band insulator ($N_{\rm c}=4$). Finally, we observe a Mott
insulator behavior in the strong interaction $U$ regions for both $N_{\rm c}=4$
and $N_{\rm c}=48$ independent of the disorder strength. We discuss the
application of this model to real materials.


title:
Uplink Spectral Efficiency Analysis of Decoupled Access in Multiuser
  MIMO Communications

abstract:
  In a heterogeneous network consisting of macro base stations (MBSs) and small
base stations (SBSs), the traditional cell association policy, i.e., coupled
access (CA), is far from optimal, due to the significant difference between the
coverage and transmit powers of MBSs and SBSs. Hence, users may choose to
associate with different types of BSs in downlink (DL) and uplink (UL), i.e.,
decoupled access (DA), to enhance spectral efficiency. In this paper, DA in
multiuser MIMO communications is investigated in terms of UL spectral
efficiency. Firstly, we obtain the UL association probabilities. In contrast to
the CA scenario, association probabilities for DA scenario only depend on the
densities of BSs. Hence, DA allows UL and DL to be totally independent.
Secondly, we derive lower bounds on the spectral efficiency. The lower bounds
show that, different from CA, the UL spectral efficiency for DA scenario is
irrelative with the transmit powers of BSs, which implies DA allows users to
associate with any BSs that can achieve the highest UL spectral efficiency.
Finally, the spectral efficiencies for DA and CA scenarios are compared via
simulation results, where it can be concluded that the spectral efficiency in
multiuser MIMO systems is improved by DA.


title: Menshov' "adjustment theorem" with respect to general measures

abstract:
  A classical theorem of Menshov states that every measurable function can
redefined on a set of arbitrarily small Lebesgue measure, so that the resulting
function has uniformly convergent Fourier series. We prove that the same is
true if we replace Lebesgue measure with an arbitrary Borel measure.


title: The Many-agent limit of the Extreme Introvert-Extrovert model

abstract:
  We consider a toy model of interacting extrovert and introvert agents
introduced earlier by Liu et al [Europhys. Lett. {\bf 100} (2012) 66007]. The
number of extroverts, and introverts is $N$ each. At each time step, we select
an agent at random, and allow her to modify her state. If an extrovert is
selected, she adds a link at random to an unconnected introvert. If an
introvert is selected, she removes one of her links. The set of $N^2$ links
evolves in time, and may be considered as a set of Ising spins on an $N \times
N$ square-grid with single-spin-flip dynamics. This dynamics satisfies detailed
balance condition, and the probability of different spin configurations in the
steady state can be determined exactly. The effective hamiltonian has
long-range multi-spin couplings that depend on the row and column sums of
spins. If the relative bias of choosing an extrovert over an introvert is
varied, this system undergoes a phase transition from a state with very few
links to one in which most links are occupied. We show that the behavior of the
system can be determined exactly in the limit of large $N$. The behavior of
large fluctuations in the total numer of links near the phase transition is
determined. We also discuss two variations, called egalitarian and elitist
agents, when the agents preferentially add or delete links to their least/
most-connected neighbor. These shows interesting cooperative behavior.


title:
Energy-Efficient Resource Allocation for Mobile-Edge Computation
  Offloading (Extended Version)

abstract:
  Mobile-edge computation offloading (MECO) offloads intensive mobile
computation to clouds located at the edges of cellular networks. Thereby, MECO
is envisioned as a promising technique for prolonging the battery lives and
enhancing the computation capacities of mobiles. In this paper, we study
resource allocation for a multiuser MECO system based on time-division multiple
access (TDMA) and orthogonal frequency-division multiple access (OFDMA). First,
for the TDMA MECO system with infinite or finite computation capacity, the
optimal resource allocation is formulated as a convex optimization problem for
minimizing the weighted sum mobile energy consumption under the constraint on
computation latency. The optimal policy is proved to have a threshold-based
structure with respect to a derived offloading priority function, which yields
priorities for users according to their channel gains and local computing
energy consumption. As a result, users with priorities above and below a given
threshold perform complete and minimum offloading, respectively. Moreover, for
the cloud with finite capacity, a sub-optimal resource-allocation algorithm is
proposed to reduce the computation complexity for computing the threshold.
Next, we consider the OFDMA MECO system, for which the optimal resource
allocation is formulated as a non-convex mixed-integer problem. To solve this
challenging problem and characterize its policy structure, a sub-optimal
low-complexity algorithm is proposed by transforming the OFDMA problem to its
TDMA counterpart. The corresponding resource allocation is derived by defining
an average offloading priority function and shown to have close-to-optimal
performance by simulation.


title:
Highly efficient coherent optical memory based on electromagnetically
  induced transparency

abstract:
  Quantum memory is an important component in the long-distance quantum
communication system based on the quantum repeater protocol. To outperform the
direct transmission of photons with quantum repeaters, it is crucial to develop
quantum memories with high fidelity, high efficiency and a long storage time.
Here, we achieve a storage efficiency of 92.0(1.5)\% for a coherent optical
memory based on the electromagnetically induced transparency (EIT) scheme in
optically dense cold atomic media. We also obtain a useful time-bandwidth
product of 1200, considering only storage where the retrieval efficiency
remains above 50\%. Both are the best record to date in all kinds of the
schemes for the realization of optical memory. Our work significantly advances
the pursuit of a high-performance optical memory and should have important
applications in quantum information science.


title:
Testing the dark matter scenario in the inert doublet model by future
  precision measurements of the Higgs boson couplings

abstract:
  We evaluate radiative corrections to the Higgs boson couplings in the inert
doublet model, in which the lightest component of the $Z_2^{}$ odd scalar
doublet field can be a dark matter candidate. The one-loop contributions to the
$hVV$, $hff$ and $hhh$ couplings are calculated in the on-shell scheme, where
$h$ is the Higgs boson with the mass 125 GeV, $V$ represents a weak gauge boson
and $f$ is a fermion. We investigate how the one-loop corrected Higgs boson
couplings can be deviated from the predictions in the standard model under the
constraints from perturbative unitarity and vacuum stability in the scenario
where the model can explain current dark matter data. When the mass of the dark
matter is slightly above a half of the Higgs boson mass, it would be difficult
to test the model by the direct search experiments for dark matter. We find
that in such a case the model can be tested at future collider experiments by
either the direct search of heavier inert particles or precision measurements
of the Higgs boson couplings.


title:
Exact homogeneous master equation for open quantum systems incorporating
  initial correlations

abstract:
  We show that the exact master equation incorporating initial correlations for
open quantum systems, within the Nakajima-Zwanzig operator-projection method,
is a homegenous master equation for the reduced density matrix. We also derive
explicitly the exact master equation for a large class of bosonic and fermionic
open quantum systems incorporating initial correlations, the resulting master
equation is homogenous. We find that the effects of the initial correlations
can be fully embedded into the fluctuation dynamics through the exact
homogenous master equation. Also a generalized nonequilibrium
fluctuation-dissipation theorem incorporating the initial correlations is
obtained.


title:
Comparing submillimeter polarized emission with near-infrared
  polarization of background stars for the Vela C molecular cloud

abstract:
  We present a large-scale combination of near-infrared (near-IR) interstellar
polarization data from background starlight with polarized emission data at
submillimeter (sub-mm) wavelengths for the Vela C molecular cloud. The near-IR
data consist of more than 6700 detections probing a range of visual extinctions
between $2$ and $20\,$mag in and around the cloud. The sub-mm data was
collected in Antartica by the Balloon-borne Large Aperture Submillimeter
Telescope for Polarimetry (BLASTPol). This is the first direct combination of
near-IR and sub-mm polarization data for a molecular cloud aimed at measuring
the "polarization efficiency ratio" ($R_{\mathrm{eff}}$), a quantity that is
expected to depend only on grain intrinsic physical properties. It is defined
as $p_{500}/(p_{I}/\tau_{V})$, where $p_{500}$ and $p_{I}$ are polarization
fractions at $500\,\mu$m and $I$-band, respectively, and $\tau_{V}$ is the
optical depth. To ensure that the same column density of material is producing
both polarization from emission and from extinction, we conducted a careful
selection of near-background stars using 2MASS, $Herschel$ and $Planck$ data.
This selection excludes objects contaminated by the Galactic diffuse background
material as well as objects located in the foreground. Accounting for
statistical and systematic uncertainties, we estimate an average
$R_{\mathrm{eff}}$ value of $2.4\pm0.8$, which can be used to test the
predictions of dust grain models designed for molecular clouds when such
predictions become available. $R_{\mathrm{eff}}$ appears to be relatively flat
as a function of the cloud depth for the range of visual extinctions probed.


title:
Laboratory validation of the dual-zone phase mask coronagraph in
  broadband light at the high-contrast imaging THD-testbed

abstract:
  Specific high contrast imaging instruments are mandatory to characterize
circumstellar disks and exoplanets around nearby stars. Coronagraphs are
commonly used in these facilities to reject the diffracted light of an observed
star and enable the direct imaging and spectroscopy of its circumstellar
environment. One important property of the coronagraph is to be able to work in
broadband light.
  Among several proposed coronagraphs, the dual-zone phase mask coronagraph is
a promising solution for starlight rejection in broadband light. In this paper,
we perform the first validation of this concept in laboratory.
  First, we recall the principle of the dual-zone phase mask coronagraph. Then,
we describe the high-contrast imaging THD testbed, the manufacturing of the
components and the quality-control procedures. Finally, we study the
sensitivity of our coronagraph to low-order aberrations (inner working angle
and defocus) and estimate its contrast performance. Our experimental broadband
light results are compared with numerical simulations to check agreement with
the performance predictions.
  With the manufactured prototype and using a dark hole technique based on the
self-coherent camera, we obtain contrast levels down to $2\,10^{-8}$ between 5
and 17$\,\lambda_0/D$ in monochromatic light (640 nm). We also reach contrast
levels of $4\,10^{-8}$ between 7 and 17$\lambda_0/D$ in broadband
($\lambda_0=675$ nm, $\Delta\lambda=250$ nm and $\Delta\lambda / \lambda_0 =
40$ %), which demonstrates the excellent chromatic performance of the dual-zone
phase mask coronagraph.
  The performance reached by the dual-zone phase mask coronagraph is promising
for future high-contrast imaging instruments that aim at detecting and
spectrally characterizing old or light gaseous planets.


title: Photons with half-integral spin as q-Fermions

abstract:
  The recently discovered 'light (photons) with half-integral spin' is
interpreted as q-Fermions proposed by us in 1991, as these q-Fermions satisfy
q-deformed anti-commutation relations (pertaining to spin half) and have the
property that more than one q-Fermion can occupy a given quantum state. In this
article, in view of the recent discovery, we recall the construction of
q-Fermions and give the statistical properties of q-Fermion gas, based on our
preprint in 1992.


title:
Non-Asymptotic Gaussian Estimates for the Recursive Approximation of the
  Invariant Measure of a Diffusion

abstract:
  We obtain non-asymptotic Gaussian concentration bounds for the difference
between the invariant measure $\nu$ of an ergodic Brownian diffusion process
and the empirical distribution of an approximating scheme with decreasing time
step along a suitable class of (smooth enough) test functions f such that f --
$\nu$(f) is a coboundary of the infinitesimal generator. We show that these
bounds can still be improved when the (squared) Fr{\"o}benius norm of the
diffusion coefficient lies in this class. We apply these bounds to design
computable non-asymptotic confidence intervals for the approximating scheme. As
a theoretical application, we finally derive non-asymptotic deviation bounds
for the almost sure Central Limit Theorem.


title: Nonlinear thermoelectric efficiency of superlattice-structured nanowires

abstract:
  We theoretically investigate nonlinear ballistic thermoelectric transport in
a superlattice-structured nanowire. By a special choice of nonuniform widths of
the superlattice barriers - analogous to anti-reflection coating in optical
systems - it is possible to achieve a transmission which comes close to a
square profile as a function of energy. We calculate the low-temperature output
power and power-conversion efficiency of a thermoelectric generator based on
such a structure and show that the efficiency remains high also when operating
at a significant power. To provide guidelines for experiments, we study how the
results depend on the nanowire radius, the number of barriers, and on random
imperfections in barrier width and separation. Our results indicate that high
efficiencies can indeed be achieved with todays capabilities in epitaxial
nanowire growth.


title: Stochastic Optimization for Large-scale Optimal Transport

abstract:
  Optimal transport (OT) defines a powerful framework to compare probability
distributions in a geometrically faithful way. However, the practical impact of
OT is still limited because of its computational burden. We propose a new class
of stochastic optimization algorithms to cope with large-scale problems
routinely encountered in machine learning applications. These methods are able
to manipulate arbitrary distributions (either discrete or continuous) by simply
requiring to be able to draw samples from them, which is the typical setup in
high-dimensional learning problems. This alleviates the need to discretize
these densities, while giving access to provably convergent methods that output
the correct distance without discretization error. These algorithms rely on two
main ideas: (a) the dual OT problem can be re-cast as the maximization of an
expectation ; (b) entropic regularization of the primal OT problem results in a
smooth dual optimization optimization which can be addressed with algorithms
that have a provably faster convergence. We instantiate these ideas in three
different setups: (i) when comparing a discrete distribution to another, we
show that incremental stochastic optimization schemes can beat Sinkhorn's
algorithm, the current state-of-the-art finite dimensional OT solver; (ii) when
comparing a discrete distribution to a continuous density, a semi-discrete
reformulation of the dual program is amenable to averaged stochastic gradient
descent, leading to better performance than approximately solving the problem
by discretization ; (iii) when dealing with two continuous densities, we
propose a stochastic gradient descent over a reproducing kernel Hilbert space
(RKHS). This is currently the only known method to solve this problem, apart
from computing OT on finite samples. We backup these claims on a set of
discrete, semi-discrete and continuous benchmark problems.


title:
Hydrostatic pressure response of an oxide two-dimensional electron
  system

abstract:
  Two-dimensional electron systems with fascinating properties exist in
multilayers of standard semiconductors, on helium surfaces, and in oxides.
Compared to the two-dimensional (2D) electron gases of semiconductors, the 2D
electron systems in oxides are typically more strongly correlated and more
sensitive to the microscopic structure of the hosting lattice. This sensitivity
suggests that the oxide 2D systems are highly tunable by hydrostatic pressure.
Here we explore the effects of hydrostatic pressure on the well-characterized
2D electron system formed at LaAlO$_{3}$ -SrTiO$_{3}$ interfaces[1] and measure
a pronounced, unexpected response. Pressure of $\sim$2 GPa reversibly doubles
the 2D carrier density $n_{s}$ at 4 K. Along with the increase of $n_{s}$, the
conductivity and mobility are reduced under pressure. First-principles pressure
simulations reveal the same behavior of the carrier density and suggest a
possible mechanism of the mobility reduction, based on the dielectric
properties of both materials and their variation under external pressure.


title: Correlations between outcomes of random measurements

abstract:
  We recently showed that multipartite correlations between outcomes of random
observables detect quantum entanglement in all pure and some mixed states. In
this followup article we further develop this approach, derive a maximal amount
of such correlations, and show that they are not monotonous under local
operations and classical communication. Nevertheless, we demonstrate their
usefulness in entanglement detection with a single random observable per party.
Finally we study convex-roof extension of the correlations and provide a
closed-form necessary and sufficient condition for entanglement in rank-2 mixed
states and a witness in general.


title: Integer homology 3-spheres admit irreducible representations in SL(2,C)

abstract:
  We prove that the fundamental group of any integer homology 3-sphere
different from the 3-sphere admits irreducible representations of its
fundamental group in SL(2,C). For hyperbolic integer homology spheres this
comes with the definition, and for Seifert fibered integer homology spheres
this is well known. We prove that the splicing of any two non-trivial knots in
the 3-sphere admits an irreducible SU(2)-representation. By work of Boileau,
Rubinstein, and Wang, the general case follows. Using a result of Kuperberg, we
get the corollary that the problem of 3-sphere recognition is in the complexity
class coNP, provided the generalised Riemann hypothesis holds. To prove our
result, we establish a topological fact about the image of the
SU(2)-representation variety of a non-trivial knot complement into the
representation variety of its boundary torus, a pillowcase. For this, we use
holonomy perturbations of the Chern-Simons function in an exhaustive way - we
show that any area-preserving self-map of the pillowcase fixing the four
singular points, and which is isotopic to the identity, can be C^0-approximated
by maps which are realised geometrically through holonomy perturbations of the
flatness equation in a thickened torus. To conclude, we use a stretching
argument in instanton gauge theory, and a non-vanishing result of Kronheimer
and Mrowka for Donaldson's invariants of a 4-manifold which contains the
0-surgery of a knot as a splitting hypersurface.


title:
Combined Brillouin light scattering and microwave absorption study of
  magnon-photon coupling in a split-ring resonator/YIG film system

abstract:
  Microfocused Brillouin light scattering (BLS) and microwave absorption (MA)
are used to study magnon-photon coupling in a system consisting of a split-ring
microwave resonator and a yttrium iron garnet (YIG) film. The split-ring
resonantor is defined by optical lithography and loaded with a 1 $\mu$m-thick
YIG film grown by liquid phase epitaxy. BLS and MA spectra of the hybrid system
are simultaneously recorded as a function of the applied magnetic field
magnitude and microwave excitation frequency. Strong coupling of the magnon and
photon modes is found with a coupling strength of $g_\text{eff}/2 \pi = 63$
MHz. The combined BLS and MA data allows to study the continuous transition of
the hybridized modes from a purely magnonic to a purely photonic mode by
varying the applied magnetic field and microwave frequency. Furthermore, the
BLS data represent an up-conversion of the microwave frequency coupling to
optical frequencies.


title: Metallic Indium Monolayers on Si(111)

abstract:
  Density-functional calculations are used to identify one-atom-thick metallic
In overlayers on the Si(111) surface, which have long been sought in quest of
the ultimate two-dimensional (2D) limit of free-electron-like metallic
properties. We predict two metastable single-layer In phases, one
$\sqrt{7}\times\sqrt{3}$ phase with a coverage of 1.4 monolayer (ML; here 1 ML
refers to one In atom per top Si atom) and the other $\sqrt{7}\times\sqrt{7}$
phase with 1.43 ML, which indeed match well with experimental evidences. Both
phases reveal quasi-1D arrangements of protruded In atoms, leading to
2D-metallic but anisotropic band structures and Fermi surfaces. This
directional feature contrasts with the free-electron-like In-overlayer
properties that are known to persist up to the double-layer thickness, implying
that we may have achieved the 2D limit of free-electron-like In overlayers in
previous studies of double-layer In phases.


title:
Episodic High Velocity Outflows from V899 Mon: A Constraint On The
  Outflow Mechanisms

abstract:
  We report the detection of large variations in the outflow wind velocity from
a young eruptive star, V899 Mon during its ongoing high accretion outburst
phase. Such large variations in the outflow velocity (from -722 km s$^{-1}$ to
-425 km s$^{-1}$) have never been reported previously in this family of
objects. Our continuous monitoring of this source shows that the
multi-component, clumpy, and episodic high velocity outflows are stable in the
time scale of a few days, and vary over the time scale of a few weeks to
months. We detect significant decoupling in the instantaneous outflow strength
to accretion rate. From the comparison of various possible outflow mechanisms
in magnetospheric accretion of young stellar objects, we conclude magnetically
driven polar winds to be the most consistent mechanism for the outflows seen in
V899 Mon. The large scale fluctuations in outflow over the short period makes
V899 Mon the most ideal source to constrain various magnetohydrodynamics (MHD)
simulations of magnetospheric accretion.
  *footnote: based on observations made with the Southern African Large
Telescope (SALT)


title:
On the two-filter approximations of marginal smoothing distributions in
  general state space models

abstract:
  A prevalent problem in general state space models is the approximation of the
smoothing distribution of a state conditional on the observations from the
past, the present, and the future. The aim of this paper is to provide a
rigorous analysis of such approximations of smoothed distributions provided by
the two-filter algorithms. We extend the results available for the
approximation of smoothing distributions to these two-filter approaches which
combine a forward filter approximating the filtering distributions with a
backward information filter approximating a quantity proportional to the
posterior distribution of the state given future observations.


title: Deep API Learning

abstract:
  Developers often wonder how to implement a certain functionality (e.g., how
to parse XML files) using APIs. Obtaining an API usage sequence based on an
API-related natural language query is very helpful in this regard. Given a
query, existing approaches utilize information retrieval models to search for
matching API sequences. These approaches treat queries and APIs as bag-of-words
(i.e., keyword matching or word-to-word alignment) and lack a deep
understanding of the semantics of the query.
  We propose DeepAPI, a deep learning based approach to generate API usage
sequences for a given natural language query. Instead of a bags-of-words
assumption, it learns the sequence of words in a query and the sequence of
associated APIs. DeepAPI adapts a neural language model named RNN
Encoder-Decoder. It encodes a word sequence (user query) into a fixed-length
context vector, and generates an API sequence based on the context vector. We
also augment the RNN Encoder-Decoder by considering the importance of
individual APIs. We empirically evaluate our approach with more than 7 million
annotated code snippets collected from GitHub. The results show that our
approach generates largely accurate API sequences and outperforms the related
approaches.


title: Band gap engineering of PtSe2

abstract:
  Besides its predicted promising high electron mobilities at room temperature,
PtSe2 bandgap sensitively depends on the number of monolayers combined by van
der Waals interaction according to our calculations. We understand this by
using bandstructure calculations based on the density functional theory. It was
found that the front orbitals of VBM and CBM are contributed mainly from pz and
px+y orbitals of Se which are sensitive to the out-plane and in-plane lattice
constants, respectively. The van der Waals force enhances the bonding
out-of-plane, which in-turn influences the bonding in-plane. We found that the
thickness dependent bandgap has the same origin as the strain dependent
bandgap, which is from the change of the front orbital interactions. The work
shows the flexibilities of tuning the electronic and optical properties of this
compound in a wide range.


title:
Performance of a resistive plate chamber equipped with a new prototype
  of amplified front-end electronics

abstract:
  ALICE is the LHC experiment dedicated to the study of heavy-ion collisions.
At forward rapidity a muon spectrometer detects muons from low mass mesons,
quarkonia, open heavy-flavor hadrons as well as weak bosons. A muon selection
based on transverse momentum is made by a trigger system composed of 72
resistive plate chambers (RPCs). For the LHC Run 1 and the ongoing Run 2 the
RPCs have been equipped with a non-amplified FEE called ADULT. However, in view
of an increase in luminosity expected for Run 3 (2021-2023) the possibility to
use an amplified FEE has been explored in order to improve the counting rate
limitation and to prevent the aging of the detector, by reducing the charge per
hit. A prototype of this new electronics (FEERIC) has been developed and tested
first with cosmic rays before equipping one RPC in the ALICE cavern with it. In
this paper the most important performance indicators - efficiency, dark
current, dark rate, cluster size and total charge - of an RPC equipped with
this new FEE will be reviewed and compared to the others read out with ADULT,
in pp collisions at 5 and 13 TeV and in Pb-Pb collisions at 5 TeV.


title:
Maximum Semidefinite and Linear Extension Complexity of Families of
  Polytopes

abstract:
  We relate the maximum semidefinite and linear extension complexity of a
family of polytopes to the cardinality of this family and the minimum pairwise
Hausdorff distance of its members. This result directly implies a known lower
bound on the maximum semidefinite extension complexity of 0/1-polytopes. We
further show how our result can be used to improve on the corresponding bounds
known for polygons with integer vertices.
  Our geometric proof builds upon nothing else than a simple well-known
property of maximum volume inscribed ellipsoids of convex bodies. In
particular, it does not rely on factorizations over the semidefinite cone and
thus avoids involved procedures of balancing them as required, e.g., in [Briet,
Dadush & Pokutta 2015]. We hope that revealing the geometry behind the
phenomenon opens doors for further results.
  Moreover, we show that the linear extension complexity of every d-dimensional
0/1-polytope is bounded from above by O(2^d / d).


title:
Specular Andreev reflection at the edge of an InAs/GaSb double quantum
  well with band inversion

abstract:
  We experimentally investigate transport through the side junction between a
niobium superconductor and the mesa edge of a two-dimensional system, realized
in an InAs/GaSb double quantum well with band inversion. We demonstrate, that
different transport regimes can be achieved by variation of the mesa step. We
observe anomalous behavior of Andreev reflection within a finite low-bias
interval, which is invariant for both transport regimes. We connect this
behavior with the transition from retro- (at low biases) to specular (at high
ones) Andreev reflection channels in an InAs/GaSb double quantum well with band
inversion.


title: Induced Minor Free Graphs: Isomorphism and Clique-width

abstract:
  Given two graphs $G$ and $H$, we say that $G$ contains $H$ as an induced
minor if a graph isomorphic to $H$ can be obtained from $G$ by a sequence of
vertex deletions and edge contractions. We study the complexity of Graph
Isomorphism on graphs that exclude a fixed graph as an induced minor. More
precisely, we determine for every graph $H$ that Graph Isomorphism is
polynomial-time solvable on $H$-induced-minor-free graphs or that it is
GI-complete. Additionally, we classify those graphs $H$ for which
$H$-induced-minor-free graphs have bounded clique-width. These two results
complement similar dichotomies for graphs that exclude a fixed graph as an
induced subgraph, minor, or subgraph.


title:
Inhomogeneous superconductivity in the presence of time-reversal
  symmetry

abstract:
  We propose a new type of non-uniform condensate state in the presence of
time-reversal symmetry. The underlying platform of this state is a corrugated
honeycomb lattice which exhibits an inhomogeneous pseudo magnetic field. Using
the self-consistent tight-binding Bogoliubov-de Gennes formalism, we show that
an s-wave pairing of chiral carriers in the presence of an inhomogeneous pseudo
magnetic field results in a spatially modulated order parameter with the half
wavelength of the corrugation. The manner of modulation depends on the
fundamental directions of the honeycomb lattice, the zigzag and armchair
directions. The stability of this inhomogeneous superconductivity is also
analyzed and possible experimental realization is discussed.


title:
Distributed controller-estimator for target tracking of networked
  robotic systems under sampled interaction

abstract:
  This paper investigates the target tracking problem for networked robotic
systems (NRSs) under sampled interaction. The target is assumed to be
time-varying and described by a second-order oscillator. Two novel distributed
controller-estimator algorithms (DCEA), which consist of both continuous and
discontinuous signals, are presented. Based on the properties of small-value
norms and Lyapunov stability theory, the conditions on the interaction
topology, the sampling period, and the other control parameters are given such
that the practical stability of the tracking error is achieved and the
stability region is regulated quantitatively. The advantages of the presented
DCEA are illustrated by comparisons with each other and the existing
coordination algorithms. Simulation examples are given to demonstrate the
theoretical results.


title: Lazy Evaluation of Convolutional Filters

abstract:
  In this paper we propose a technique which avoids the evaluation of certain
convolutional filters in a deep neural network. This allows to trade-off the
accuracy of a deep neural network with the computational and memory
requirements. This is especially important on a constrained device unable to
hold all the weights of the network in memory.


title:
Low-Energy Excitations and Ground State Selection in Quantum Breathing
  Pyrochlore Antiferromagnet Ba$_3$Yb$_2$Zn$_5$O$_{11}$

abstract:
  We study low energy excitations in the quantum breathing pyrochlore
antiferromagnet Ba$_3$Yb$_2$Zn$_5$O$_{11}$ by combination of inelastic neutron
scattering (INS) and thermodynamical properties measurements. The INS spectra
are quantitatively explained by spin-1/2 single-tetrahedron model having $XXZ$
anisotropy and Dzyaloshinskii-Moriya interaction. This model has a two-fold
degeneracy of the lowest-energy state per tetrahedron and well reproduces the
magnetization curve at 0.5 K and heat capacity above 1.5 K. At lower
temperatures, however, we observe a broad maximum in the heat capacity around
63 mK, demonstrating that a unique quantum ground state is selected due to
extra perturbations with energy scale smaller than the instrumental resolution
of INS.


title:
Geometric conditions for $\square$-irreducibility of certain
  representations of the general linear group over a non-archimedean local
  field

abstract:
  Let $\pi$ be an irreducible, complex, smooth representation of $GL_n$ over a
local non-archimedean (skew) field. Assuming $\pi$ has regular Zelevinsky
parameters, we give a geometric necessary and sufficient criterion for the
irreducibility of the parabolic induction of $\pi\otimes\pi$ to $GL_{2n}$. The
latter irreducibility property is the $p$-adic analogue of a special case of
the notion of "real representations" introduced by Leclerc and studied recently
by Kang-Kashiwara-Kim-Oh (in the context of KLR or quantum affine algebras).
Our criterion is in terms of singularities of Schubert varieties of type $A$
and admits a simple combinatorial description. It is also equivalent to a
condition studied by Geiss-Leclerc-Schr\"oer.


title:
Two-body Charmed $B$ Meson Decays In Factorization Assisted Topological
  Amplitude Approach

abstract:
  We analyze the two-body charmed $B$ meson decays $B_{u,d,s} \to D^{(*)}P(V)$
in the factorization assisted topological amplitude approach, where $P(V)$
denoting a light pseudoscalar (vector) meson. Different from the conventional
topological diagram approach, flavor $SU(3)$ symmetry breaking effects are
taken into account. Therefore only four universal nonperturbative parameters
are introduced to describe the contribution from non-factorization diagrams for
all the decay channels. The number of free parameters and the $\chi^2$ per
degree of freedom are both significantly reduced comparing with the
conventional topological diagram approach. With the 4 fitted parameters, we
predict the branching fractions of 120 decay modes induced by both $b\to c$ and
$b\to u$ transitions, which are well consistent with the measured data or to be
tested on the future experiments. We also investigated the relative size of
different topological diagrams, isospin violation, flavor $SU(3)$ symmetry
breaking effects, compared with previous approaches.


title: Experimental ten-photon entanglement

abstract:
  Quantum entanglement among multiple spatially separated particles is of
fundamental interest, and can serve as central resources for studies in quantum
nonlocality, quantum-to-classical transition, quantum error correction, and
quantum simulation. The ability of generating an increasing number of entangled
particles is an important benchmark for quantum information processing. The
largest entangled states were previously created with fourteen trapped ions,
eight photons, and five superconducting qubits. Here, based on spontaneous
parametric down-converted two-photon entanglement source with simultaneously a
high brightness of ~12 MHz/W, a collection efficiency of ~70% and an
indistinguishability of ~91% between independent photons, we demonstrate, for
the first time, genuine and distillable entanglement of ten single photons
under different pump power. Our work creates a state-of-the-art platform for
multi-photon experiments, and provide enabling technologies for challenging
optical quantum information tasks such as high-efficiency scattershot boson
sampling with many photons.


title: Journeys & Notes: Designing Social Computing for Non-Places

abstract:
  In this work we present a mobile application we designed and engineered to
enable people to log their travels near and far, leave notes behind, and build
a community around spaces in between destinations. Our design explores new
ground for location-based social computing systems, identifying opportunities
where these systems can foster the growth of on-line communities rooted at
non-places. In our work we develop, explore, and evaluate several innovative
features designed around four usage scenarios: daily commuting, long-distance
traveling, quantified traveling, and journaling. We present the results of two
small-scale user studies, and one large-scale, world-wide deployment,
synthesizing the results as potential opportunities and lessons learned in
designing social computing for non-places.


title:
XMM-Newton reveals a Seyfert-like X-ray spectrum in the z=3.6 QSO
  B1422+231

abstract:
  Matter flows in the central regions of quasars during their active phases are
probably responsible for the properties of the super-massive black holes and
that of the bulges of host galaxies. To understand how this mechanism works, we
need to characterize the geometry and the physical state of the accreting
matter at cosmological redshifts. The few high quality X-ray spectra of distant
QSO have been collected by adding sparse pointings of single objects obtained
during X-ray monitoring campaigns. This could have introduced spurious spectral
features due to source variability. Here we present a single epoch,
high-quality X-ray spectrum of the z=3.62 quasar B1422+231 whose flux is
enhanced by gravitationally lensing (F$_{2-10 keV}\sim$10$^{-12}$erg s$^{-1}$
cm$^{-2}$). The X-ray spectrum of B1422+231 is found to be very similar to the
one of a typical nearby Seyfert galaxy. Neutral absorption is detected
(N$_{H}\sim$5$\times$10$^{21}$ cm$^{-2}$ at the redshift of the source) while a
strong absorption edge is measured at E$\sim$7.5 keV with an optical depth of
$\tau\sim$0.14. We also find hints of the FeK$\alpha$ line in emission at
E$\sim$6.4 keV line (EW$\lesssim$70 eV) and a hump is detected in the
E$\sim$15-20 keV energy band (rest-frame) suggesting the presence of a
reflection component. In this scenario, the primary emission of B1422+231 is
most probably dominated by the thermal Comptonization of UV seed photons in a
corona with kT$\sim$40 keV and the reflection component has a relative
direct-to-reflect normalization r$\sim$1. These findings confirm that
gravitational lensing is effective to obtain good quality X-ray spectral
information of quasar at high-z, moreover they support the idea that the same
general picture characterizing active galactic nuclei in the nearby Universe is
valid also at high redshift.


title: Complete biconservative surfaces in $\mathbb{R}^3$ and $\mathbb{S}^3$

abstract:
  In this paper we consider the complete biconservative surfaces in Euclidean
space $\mathbb{R}^3$ and in the unit Euclidean sphere $\mathbb{S}^3$.
Biconservative surfaces in 3-dimensional space forms are characterized by the
fact that the gradient of their mean curvature function is an eigenvector of
the shape operator, and we are interested in studying local and global
properties of such surfaces with non-constant mean curvature function. We
determine the simply connected, complete Riemannian surfaces that admit
biconservative immersions in $\mathbb{R}^3$ and $\mathbb{S}^3$. Moreover, such
immersions are explicitly described.