title:
Rotating Stars and the Formation of Bipolar Planetary Nebulae II: Tidal
  Spin-up

abstract:
  We present new binary stellar evolution models that include the effects of
tidal forces, rotation, and magnetic torques with the goal of testing Planetary
Nebulae (PNe) shaping via binary interaction. We explore whether tidal
interaction with a companion can spin up the AGB envelope. To do so we have
selected binary systems with main sequence masses of 2.5 \Mo and of 0.8 \Mo and
evolve them allowing initial separations of 5, 6, 7, and 8 AU. The binary
stellar evolution models have been computed all the way to the PNe formation
phase or until Roche lobe overflow (RLOF) is reached, whatever happens first.
We show that with initial separations of 7 and 8 AU, the binary avoids entering
into RLOF, and the AGB star reaches moderate rotational velocities at the
surface ($\sim 3.5 $ and $\sim 2 $ \kms respectively) during the inter-pulse
phases, but after the thermal pulses it drops to a final rotational velocity of
only $\sim 0.03 $ \kms. For the closest binary separations explored, 5 and 6
AU, the AGB star reaches rotational velocities of $\sim 6 $ and $\sim 4 $ \kms
respectively when the RLOF is initiated. We conclude that the detached binary
models that avoid entering the RLOF phase during the AGB will not shape bipolar
PNe, since the acquired angular momentum is lost via the wind during the last
two thermal pulses. This study rules out tidal spin-up in non-contact binaries
as a sufficient condition to form bipolar PNe.


title: Market Share Analysis with Brand Effect

abstract:
  In this paper, we investigate the effect of brand in market competition.
Specifically, we propose a variant Hotelling model where companies and
customers are represented by points in an Euclidean space, with axes being
product features. $N$ companies compete to maximize their own profits by
optimally choosing their prices, while each customer in the market, when
choosing sellers, considers the sum of product price, discrepancy between
product feature and his preference, and a company's brand name, which is
modeled by a function of its market area of the form $-\beta\cdot\text{(Market
Area)}^q$, where $\beta$ captures the brand influence and $q$ captures how
market share affects the brand. By varying the parameters $\beta$ and $q$, we
derive existence results of Nash equilibrium and equilibrium market prices and
shares. In particular, we prove that pure Nash equilibrium always exists when
$q=0$ for markets with either one and two dominating features, and it always
exists in a single dominating feature market when market affects brand name
linearly, i.e., $q=1$. Moreover, we show that at equilibrium, a company's price
is proportional to its market area over the competition intensity with its
neighbors, a result that quantitatively reconciles the common belief of a
company's pricing power. We also study an interesting "wipe out" phenomenon
that only appears when $q>0$, which is similar to the "undercut" phenomenon in
the Hotelling model, where companies may suddenly lose the entire market area
with a small price increment. Our results offer novel insight into market
pricing and positioning under competition with brand effect.


title: On the uniform one-dimensional fragment

abstract:
  The uniform one-dimensional fragment of first-order logic, U1, is a recently
introduced formalism that extends two-variable logic in a natural way to
contexts with relations of all arities. We survey properties of U1 and
investigate its relationship to description logics designed to accommodate
higher arity relations, with particular attention given to DLR_reg. We also
define a description logic version of a variant of U1 and prove a range of new
results concerning the expressivity of U1 and related logics.


title: OFFl models: novel schema for dynamical modeling of biological systems

abstract:
  Flow diagrams are a common tool used to help build and interpret models of
dynamical systems, often in biological contexts such as consumer-resource
models and similar compartmental models. Typically, their usage is intuitive
and informal. Here, we present a formalized version of flow diagrams as a kind
of weighted directed graph which follow a strict grammar, which translate into
a system of ordinary differential equations (ODEs) by a single unambiguous
rule, and which have an equivalent representation as a relational database. (We
abbreviate this schema of "ODEs and formalized flow diagrams" as OFFl.) Drawing
a diagram within this strict grammar encourages a mental discipline on the part
of the modeler in which all dynamical processes of a system are thought of as
interactions between dynamical species that draw parcels from one or more
source species and deposit them into target species according to a set of
transformation rules. From these rules, the net rate of change for each species
can be derived. The modeling schema can therefore be understood as both an
epistemic and practical heuristic for modeling, serving both as an
organizational framework for the model building process and as a mechanism for
deriving ODEs. All steps of the schema beyond the initial scientific
(intuitive, creative) abstraction of natural observations into model variables
are algorithmic and easily carried out by a computer, thus enabling the future
development of a dedicated software implementation. Such tools would empower
the modeler to consider significantly more complex models than practical
limitations might have otherwise proscribed, since the modeling framework
itself manages that complexity on the modeler's behalf. In this report, we
describe the chief motivations for OFFl, outline its implementation, and
utilize a range of classic examples from ecology and epidemiology to showcase
its features.


title:
Modeling QoE of Video Streaming in Wireless Networks with Large-Scale
  Measurement of User Behavior

abstract:
  Unraveling quality of experience (QoE) of video streaming is very challenging
in bandwidth shared wireless networks. It is unclear how QoE metrics such as
starvation probability and buffering time interact with dynamics of streaming
traffic load. In this paper, we collect view records from one of the largest
streaming providers in China over two weeks and perform an in-depth measurement
study on flow arrival and viewing time that shed light on the real traffic
pattern. Our most important observation is that the viewing time of streaming
users fits a hyper-exponential distribution quite well. This implies that all
the views can be categorized into two classes, short and long views with
separated time scales. We then map the measured traffic pattern to bandwidth
shared cellular networks and propose an analytical framework to compute the
closed-form starvation probability on the basis of ordinary differential
equations (ODEs). Our framework can be naturally extended to investigate
practical issues including the progressive downloading and the finite video
duration. Extensive trace-driven simulations validate the accuracy of our
models. Our study reveals that the starvation metrics of the short and long
views possess different sensitivities to the scheduling priority at base
station. Hence, a better QoE tradeoff between the short and long views has a
potential to be leveraged by offering them different scheduling weights. The
flow differentiation involves tremendous technical and non-technical challenges
because video content is owned by content providers but not the network
operators and the viewing time of each session is unknown beforehand. To
overcome these difficulties, we propose an online Bayesian approach to infer
the viewing time of each incoming flow with the "least" information from
content providers.


title: Perturbation theory for string sigma models

abstract:
  In this thesis we investigate quantum aspects of the Green-Schwarz
superstring in various AdS backgrounds relevant for the AdS/CFT correspondence,
providing several examples of perturbative computations in the corresponding
integrable sigma-models. We start by reviewing in details the supercoset
construction of the superstring action in $AdS_5 \times S^5$, pointing out the
limits of this procedure for $AdS_4$ and $AdS_3$ backgrounds. For the $AdS_4
\times CP^3$ case we give a thorough derivation of an alternative action, based
on the double-dimensional reduction of eleven-dimensional super-membranes. We
then consider the expansion about the BMN vacuum and the S-matrix for the
scattering of worldsheet excitations in the decompactification limit. To
evaluate its elements efficiently we describe a unitarity-based method
resulting in a very compact formula yielding the cut-constructible part of any
one-loop two-dimensional S-matrix. In the second part of this review we analyze
the superstring action on $AdS_4 \times CP^3$ expanded around the null cusp
vacuum. The free energy of this model, whose computation we reproduce up to
two-loops at strong coupling, is related to the cusp anomalous dimension of the
ABJM theory and, indirectly, to a non-trivial effective coupling $h(\lambda)$
featuring all integrability-based calculations in $AdS_4/CFT_3$. Finally, we
extensively discuss the comparison of the perturbative results and the
integrability predictions for the one-loop dispersion relation of GKP
excitations. Our results provide valuable data in support of the quantum
consistency of the string actions - often debated due to possible issues with
cancellation of UV divergences and the lack of manifest power-counting
renormalizability - and furnish non-trivial stringent tests for the quantum
integrability of the analyzed models.


title: Quantum Interpolation for High Resolution Sensing

abstract:
  Recent advances in engineering and control of nanoscale quantum sensors have
opened new paradigms in precision metrology. Unfortunately, hardware
restrictions often limit the sensor performance. In nanoscale magnetic
resonance probes, for instance, finite sampling times greatly limit the
achievable sensitivity and spectral resolution. We develop a technique for
coherent quantum interpolation that can overcome these problems. Using a
quantum sensor associated with the Nitrogen Vacancy center in diamond, we
experimentally demonstrate that quantum interpolation can achieve spectroscopy
of classical magnetic fields and individual quantum spins with orders of
magnitude finer frequency resolution than conventionally possible. Not only is
quantum interpolation an enabling technique to extract structural and chemical
information from single biomolecules, but it can be directly applied to other
quantum systems for super-resolution quantum spectroscopy.


title:
Thermodynamically consistent description of criticality in models of
  correlated electrons

abstract:
  Criticality in models of correlated electrons emerges in proximity of a
low-temperature singularity in a two-particle Green function. Such
singularities are generally related to a symmetry breaking of the one-particle
self-energy. A consistent description demands that the symmetry breaking in the
self-energy emerges at the critical point of the respective two-particle
function. This cannot easily be achieved in models of correlated electrons,
since there are two ways connecting one- and two-electron functions that cannot
be made fully equivalent in approximations. We present a general construction
of diagrammatic two-particle approximations consistent with the one-particle
functions so that both produce qualitatively the same quantum critical behavior
in thermodynamically equivalent descriptions. The general scheme is applied on
the single-impurity Anderson model to derive qualitatively the same Kondo
critical scale from the spectral function and the magnetic susceptibility.


title: Coherence for monoidal $G$-categories and braided $G$-crossed categories

abstract:
  We prove a coherence theorem for actions of groups on monoidal categories. As
an application we prove coherence for arbitrary braided $G$-crossed categories.


title: The Complex Hierarchical Topology of EEG Functional Connectivity

abstract:
  Understanding the complex hierarchical topology of functional brain networks
is a key aspect of functional connectivity research. Such topics are obscured
by the widespread use of sparse binary network models which are fundamentally
different to the complete weighted networks derived from functional
connectivity. We introduce two techniques to probe the hierarchical complexity
of topologies. Firstly, a new metric to measure hierarchical complexity;
secondly, a Weighted Complex Hierarchy (WCH) model. To thoroughly evaluate our
techniques, we generalise sparse binary network archetypes to weighted forms
and explore the main topological features of brain networks- integration,
regularity and modularity- using curves over density. By controlling the
parameters of our model, the highest complexity is found to arise between a
random topology and a strict 'class-based' topology. Further, the model has
equivalent complexity to EEG phase-lag networks at peak performance.
Hierarchical complexity attains greater magnitude and range of differences
between different networks than the previous commonly used complexity metric
and our WCH model offers a much broader range of network topology than the
standard scale-free and small-world models at a full range of densities. Our
metric and model provide a rigorous characterisation of hierarchical
complexity. Importantly, our framework shows a scale of complexity arising
between 'all nodes are equal' topologies at one extreme and 'strict
class-based' topologies at the other.


title:
Anomalous Phase Shift of Quantum Oscillations in 3D Topological
  Semimetals

abstract:
  Berry phase physics is closely related to a number of topological states of
matter. Recently discovered topological semimetals are believed to host a
nontrivial $\pi$ Berry phase to induce a phase shift of $\pm 1/8$ in the
quantum oscillation ($+$ for hole and $-$ for electron carriers). We
theoretically study the Shubnikov-de Haas oscillation of Weyl and Dirac
semimetals, taking into account their topological nature and inter-Landau band
scattering. For a Weyl semimetal with broken time-reversal symmetry, the phase
shift is found to change nonmonotonically and go beyond known values of $\pm
1/8$ and $\pm 5/8$. For a Dirac semimetal or paramagnetic Weyl semimetal,
time-reversal symmetry leads to a discrete phase shift of $\pm 1/8$ or $\pm
5/8$, as a function of the Fermi energy. Different from the previous works, we
find that the topological band inversion can lead to beating patterns in the
absence of Zeeman splitting. We also find the resistivity peaks should be
assigned integers in the Landau index plot. Our findings may account for recent
experiments in Cd$_2$As$_3$ and should be helpful for exploring the Berry phase
in various 3D systems.


title:
Contributions of loops with dynamical vector mesons to masses and decay
  constants of pseudoscalar mesons and their quark mass dependence

abstract:
  The contributions of one-loop diagrams with dynamical vector mesons to masses
and decay constants of pseudoscalar mesons are determined. Hereby, a
relativistic Lagrangian for both the pseudoscalar-meson octet and the
vector-meson nonet is used. The vector mesons are given in the antisymmetric
tensor representation. Both the differences between static and dynamical vector
mesons and the differences between calculations with and without vector mesons
are studied as functions of the light quark mass.


title:
Fusing Face and Periocular biometrics using Canonical correlation
  analysis

abstract:
  This paper presents a novel face and periocular biometric fusion at feature
level using canonical correlation analysis. Face recognition itself has
limitations such as illumination, pose, expression, occlusion etc. Also,
periocular biometrics has spectacles, head angle, hair and expression as its
limitations. Unimodal biometrics cannot surmount all these limitations. The
recognition accuracy can be increased by fusing dual information (face and
periocular) from a single source (face image) using canonical correlation
analysis (CCA). This work also proposes a new wavelet decomposed local binary
pattern (WD-LBP) feature extractor which provides sufficient features for
fusion. A detailed analysis on face and periocular biometrics shows that WD-LBP
features are more accurate and faster than local binary pattern (LBP) and gabor
wavelet. The experimental results using Muct face database reveals that the
proposed multimodal biometrics performs better than the unimodal biometrics.


title:
Face Image Analysis using AAM, Gabor, LBP and WD features for Gender,
  Age, Expression and Ethnicity Classification

abstract:
  The growth in electronic transactions and human machine interactions rely on
the information such as gender, age, expression and ethnicity provided by the
face image. In order to obtain these information, feature extraction plays a
major role. In this paper, retrieval of age, gender, expression and race
information from an individual face image is analysed using different feature
extraction methods. The performance of four major feature extraction methods
such as Active Appearance Model (AAM), Gabor wavelets, Local Binary Pattern
(LBP) and Wavelet Decomposition (WD) are analyzed for gender recognition, age
estimation, expression recognition and racial recognition in terms of accuracy
(recognition rate), time for feature extraction, neural training and time to
test an image. Each of this recognition system is compared with four feature
extractors on same dataset (training and validation set) to get a better
understanding in its performance. Experiments carried out on FG-NET,
Cohn-Kanade, PAL face database shows that each method has its own merits and
demerits. Hence it is practically impossible to define a method which is best
at all circumstances with less computational complexity. Further, a detailed
comparison of age estimation and age estimation using gender information is
provided along with a solution to overcome aging effect in case of gender
recognition. An attempt has been made in obtaining all (i.e. gender, age range,
expression and ethnicity) information from a test image in a single go.


title: The Cityscapes Dataset for Semantic Urban Scene Understanding

abstract:
  Visual understanding of complex urban street scenes is an enabling factor for
a wide range of applications. Object detection has benefited enormously from
large-scale datasets, especially in the context of deep learning. For semantic
urban scene understanding, however, no current dataset adequately captures the
complexity of real-world urban scenes.
  To address this, we introduce Cityscapes, a benchmark suite and large-scale
dataset to train and test approaches for pixel-level and instance-level
semantic labeling. Cityscapes is comprised of a large, diverse set of stereo
video sequences recorded in streets from 50 different cities. 5000 of these
images have high quality pixel-level annotations; 20000 additional images have
coarse annotations to enable methods that leverage large volumes of
weakly-labeled data. Crucially, our effort exceeds previous attempts in terms
of dataset size, annotation richness, scene variability, and complexity. Our
accompanying empirical study provides an in-depth analysis of the dataset
characteristics, as well as a performance evaluation of several
state-of-the-art approaches based on our benchmark.


title:
Relationship between Variants of One-Class Nearest Neighbours and
  Creating their Accurate Ensembles

abstract:
  In one-class classification problems, only the data for the target class is
available, whereas the data for the non-target class may be completely absent.
In this paper, we study one-class nearest neighbour (OCNN) classifiers and
their different variants. We present a theoretical analysis to show the
relationships among different variants of OCNN that may use different
neighbours or thresholds to identify unseen examples of the non-target class.
We also present a method based on inter-quartile range for optimising
parameters used in OCNN in the absence of non-target data during training.
Then, we propose two ensemble approaches based on random subspace and random
projection methods to create accurate OCNN ensembles. We tested the proposed
methods on 15 benchmark and real world domain-specific datasets and show that
random-projection ensembles of OCNN perform best.


title:
Nonlinear strong coupling between sub-band excitons: a new coherent path
  for ultrafast relaxation

abstract:
  We demonstrate theoretically and experimentally that the nonlinear
interaction between excitations whose harmonic energies coincide gives rise to
a strong coupling that opens a new coherent ultrafast energy relaxation path.
Instead of an incoherent decay of excitations, that should take a finite time
that depends on the energy difference between the initial state and the final
state, the nonlinear interaction allows their coherent superposition and thus
an instantaneous transfer of the excitation over energies as large as the
electron-volt. Such a situation should be encountered in many systems. We
demonstrate that such a model applies also for excitons in single-wall carbon
nanotubes (SWCNT) where a strong nonlinear Coulomb interaction occurs between
$\rm E_{11}$ and $\rm E_{22}$ states. This explains a wide panel of
observations about optoelectronic properties of the SWCNT and gives a coherent
picture of their features like the exciton-line spectral positions, exciton
collisions and their ultrafast relaxation, as well as the low light-emission
efficiency of the nanotubes.


title: Chemical potential asymmetry and quantum oscillations in insulators

abstract:
  We present a theory of quantum oscillations in insulators that are
particle-hole symmetric and non-topological but with arbitrary band dispersion,
at both zero and non-zero temperature. At temperatures $T$ less than or
comparable to the gap, the dependence of oscillations on $T$ is markedly
different from that in metals and depends crucially on the position of the
chemical potential $\mu$ in the gap. If $\mu$ is in the middle of the gap,
oscillations do not change with $T$; however, if $\mu$ is asymmetrically
positioned in the gap, surprisingly, oscillations go to zero at a critical
value of the inverse field determined by $T$ and $\mu$ and then change their
phase by $\pi$ and grow again. Additionally, the temperature dependence is
different for quantities derived from the grand canonical potential, such as
magnetization and susceptibility, and those derived from the density of states,
such as resistivity. However, the non-trivial features arising from asymmetric
$\mu$ are present in both.


title:
The ground state of the Pomeron and its decays to light mesons and
  photons

abstract:
  The problem of the timelike Pomeron coupling to light mesons and photons is
considered in light of available data on high-energy meson-proton scattering.
Possible correspondence of $f_2(1950)$ resonance to the ground state of the
Pomeron is argued.


title: Quantization condition from exact WKB for difference equations

abstract:
  A well-motivated conjecture states that the open topological string partition
function on toric geometries in the Nekrasov-Shatashvili limit is annihilated
by a difference operator called the quantum mirror curve. Recently, the complex
structure variables parameterizing the curve, which play the role of
eigenvalues for related operators, were conjectured to satisfy a quantization
condition non-perturbative in the NS parameter $\hbar$. Here, we argue that
this quantization condition arises from requiring single-valuedness of the
partition function, combined with the requirement of smoothness in the
parameter $\hbar$. To determine the monodromy of the partition function, we
study the underlying difference equation in the framework of exact WKB.


title: Integrable matrix theory: Level statistics

abstract:
  We study level statistics in ensembles of integrable $N\times N$ matrices
linear in a real parameter $x$. The matrix $H(x)$ is considered integrable if
it has a prescribed number $n>1$ of linearly independent commuting partners
$H^i(x)$ (integrals of motion) $\left[H(x),H^i(x)\right] = 0$, $\left[H^i(x),
H^j(x)\right]$ = 0, for all $x$. In a recent work, we developed a
basis-independent construction of $H(x)$ for any $n$ from which we derived the
probability density function, thereby determining how to choose a typical
integrable matrix from the ensemble. Here, we find that typical integrable
matrices have Poisson statistics in the $N\to\infty$ limit provided $n$ scales
at least as $\log{N}$; otherwise, they exhibit level repulsion. Exceptions to
the Poisson case occur at isolated coupling values $x=x_0$ or when correlations
are introduced between typically independent matrix parameters. However, level
statistics cross over to Poisson at $ \mathcal{O}(N^{-0.5})$ deviations from
these exceptions, indicating that non-Poissonian statistics characterize only
subsets of measure zero in the parameter space. Furthermore, we present strong
numerical evidence that ensembles of integrable matrices are stationary and
ergodic with respect to nearest neighbor level statistics.


title: An Ensemble Method to Produce High-Quality Word Embeddings (2016)

abstract:
  A currently successful approach to computational semantics is to represent
words as embeddings in a machine-learned vector space. We present an ensemble
method that combines embeddings produced by GloVe (Pennington et al., 2014) and
word2vec (Mikolov et al., 2013) with structured knowledge from the semantic
networks ConceptNet (Speer and Havasi, 2012) and PPDB (Ganitkevitch et al.,
2013), merging their information into a common representation with a large,
multilingual vocabulary. The embeddings it produces achieve state-of-the-art
performance on many word-similarity evaluations. Its score of $\rho = .596$ on
an evaluation of rare words (Luong et al., 2013) is 16% higher than the
previous best known system.


title: The Spatial Ecology of War and Peace

abstract:
  Human flourishing is often severely limited by persistent violence.
Quantitative conflict research has found common temporal and other statistical
patterns in warfare, but very little is understood about its general spatial
patterns. While the importance of topology in geostrategy has long been
recognised, the role of spatial patterns of cities in determining a region's
vulnerability to conflict has gone unexplored. Here, we show that global
patterns in war and peace are closely related to the relative position of
cities in a global interaction network. We find that regions with betweenness
centrality above a certain threshold are often engulfed in entrenched conflict,
while a high degree correlates with peace. In fact, betweenness accounts for
over 80% of the variance in number of attacks. This metric is also a good
predictor of the distance to a conflict zone and can estimate the risk of
conflict. We conjecture that a high betweenness identifies areas with fuzzy
cultural boundaries, whereas high degree cities are in cores where peace is
more easily maintained. This is supported by a simple agent-based model in
which cities influence their neighbours, which exhibits the same threshold
behaviour with betweenness as seen in conflict data. These findings not only
shed new light on the causes of violence, but could be used to estimate the
risk associated with actions such as the merging of cities, construction of
transportation infrastructure, or interventions in trade or migration patterns.


title:
On the classification of ancient solutions to curvature flows on the
  sphere

abstract:
  We consider the evolution of hypersurfaces on the unit sphere
$\mathbb{S}^{n+1}$ by smooth functions of the Weingarten map. We introduce the
notion of `quasi-ancient' solutions for flows that do not admit non-trivial,
convex, ancient solutions. Such solutions are somewhat analogous to ancient
solutions for flows such as the mean curvature flow, or 1-homogeneous flows.
The techniques presented here allow us to prove that any convex, quasi-ancient
solution of a curvature flow which satisfies a backwards in time uniform bound
on mean curvature must be stationary or a family of shrinking geodesic spheres.
The main tools are geometric, employing the maximum principle, a rigidity
result in the sphere and an Alexandrov reflection argument. We emphasize that
no homogeneity or convexity/concavity restrictions are placed on the speed,
though we do also offer a short classification proof for several such
restricted cases.


title: Recent Advances Concerning Certain Class of Geophysical Flows

abstract:
  This paper is devoted to reviewing several recent developments concerning
certain class of geophysical models, including the primitive equations (PEs) of
atmospheric and oceanic dynamics and a tropical atmosphere model. The PEs for
large-scale oceanic and atmospheric dynamics are derived from the Navier-Stokes
equations coupled to the heat convection by adopting the Boussinesq and
hydrostatic approximations, while the tropical atmosphere model considered here
is a nonlinear interaction system between the barotropic mode and the first
baroclinic mode of the tropical atmosphere with moisture.
  We are mainly concerned with the global well-posedness of strong solutions to
these systems, with full or partial viscosity, as well as certain singular
perturbation small parameter limits related to these systems, including the
small aspect ratio limit from the Navier-Stokes equations to the PEs, and a
small relaxation-parameter in the tropical atmosphere model. These limits
provide a rigorous justification to the hydrostatic balance in the PEs, and to
the relaxation limit of the tropical atmosphere model, respectively. Some
conditional uniqueness of weak solutions, and the global well-posedness of weak
solutions with certain class of discontinuous initial data, to the PEs are also
presented.

categories: math.AP physics.ao-ph physics.flu-dyn physics.geo-ph


title:
A Corpus and Evaluation Framework for Deeper Understanding of
  Commonsense Stories

abstract:
  Representation and learning of commonsense knowledge is one of the
foundational problems in the quest to enable deep language understanding. This
issue is particularly challenging for understanding casual and correlational
relationships between events. While this topic has received a lot of interest
in the NLP community, research has been hindered by the lack of a proper
evaluation framework. This paper attempts to address this problem with a new
framework for evaluating story understanding and script learning: the 'Story
Cloze Test'. This test requires a system to choose the correct ending to a
four-sentence story. We created a new corpus of ~50k five-sentence commonsense
stories, ROCStories, to enable this evaluation. This corpus is unique in two
ways: (1) it captures a rich set of causal and temporal commonsense relations
between daily events, and (2) it is a high quality collection of everyday life
stories that can also be used for story generation. Experimental evaluation
shows that a host of baselines and state-of-the-art models based on shallow
language understanding struggle to achieve a high score on the Story Cloze
Test. We discuss these implications for script and story learning, and offer
suggestions for deeper language understanding.


title: Online Lower Bounds via Duality

abstract:
  In this paper, we exploit linear programming duality in the online setting
(i.e., where input arrives on the fly) from the unique perspective of designing
lower bounds on the competitive ratio. In particular, we provide a general
technique for obtaining online deterministic and randomized lower bounds (i.e.,
hardness results) on the competitive ratio for a wide variety of problems. We
show the usefulness of our approach by providing new, tight lower bounds for
three diverse online problems. The three problems we show tight lower bounds
for are the Vector Bin Packing problem, Ad-auctions (and various online
matching problems), and the Capital Investment problem. Our methods are
sufficiently general that they can also be used to reconstruct existing lower
bounds.
  Our techniques are in stark contrast to previous works, which exploit linear
programming duality to obtain positive results, often via the useful
primal-dual scheme. We design a general recipe with the opposite aim of
obtaining negative results via duality. The general idea behind our approach is
to construct a primal linear program based on a collection of input sequences,
where the objective function corresponds to optimizing the competitive ratio.
We then obtain the corresponding dual linear program and provide a feasible
solution, where the objective function yields a lower bound on the competitive
ratio. Online lower bounds are often achieved by adapting the input sequence
according to an online algorithm's behavior and doing an appropriate ad hoc
case analysis. Using our unifying techniques, we simultaneously combine these
cases into one linear program and achieve online lower bounds via a more robust
analysis. We are confident that our framework can be successfully applied to
produce many more lower bounds for a wide array of online problems.


title:
Starburst galaxies in the COSMOS field: clumpy star-formation at
  redshift 0 < z < 0.5

abstract:
  At high redshift, starburst galaxies present irregular morphologies, with
10-20\%\ of their star formation occurring in giant clumps. These clumpy
galaxies are considered to be the progenitors of local disk galaxies. To
understand the properties of starbursts at intermediate and low redshift, it is
fundamental to track their evolution and possible link with the systems at
higher $z$. We present an extensive, systematic, and multi-band search and
analysis of the starburst galaxies at redshift ($0 < z < 0.5$) in the COSMOS
field, as well as detailed characteristics of their star-forming clumps by
using Hubble Space Telescope/Advance Camera for Surveys (HST/ACS) images. Their
principal properties, sizes, masses, and star formation rates are provided. The
individual star-forming knots in our sample follow the same L(H$\alpha$) vs.
size scaling relation than local giant HII regions (Fuentes-Masip et al. 2000).
However, they slightly differ from the one provided using samples at high
redshift. This result highlights the importance of spatially resolving the
star-forming regions for this kind of study. Star-forming clumps in the central
regions of Mknots galaxies are more massive, and present higher star formation
rates, than those in the outskirts. This trend is smeared when we consider
either the mass surface density or surface star formation rate. Sknot galaxies
do show properties similar to both dwarf elliptical and irregulars in the
surface brightness ($\mu$) versus M$_{host}$ diagram in the $B-$band (Amor\'in
et al. 2012), and to spheroidals and ellipticals in the $\mu$ versus M$_{host}$
diagram in the $V-$band (Kormendy \&\ Bender 2012). Sknot galaxies might be
transitional phases of the BCD class, with their properties consistent with
spheroidal like, but blue structures.


title: The $L^2$ Behavior of Eigenfunctions Near the Glancing Set

abstract:
  Let $M$ be a compact manifold with or without boundary and $H\subset M$ be a
smooth, interior hypersurface. We study the restriction of Laplace
eigenfunctions solving $(-h^2\Delta_g-1)u=0$ to $H$. In particular, we study
the degeneration of $u|_H$ as one microlocally approaches the glancing set by
finding the optimal power $s_0$ so that $(1+h^2\Delta_H)_+^{s_0}u|_H$ remains
uniformly bounded in $L^2(H)$ as $h\to 0$. Moreover, we show that this bound is
saturated at every $h$-dependent scale near glancing using examples on the disk
and sphere. We give an application of our estimates to quantum ergodic
restriction theorems.


title: The fibres of the Prym map of \'etale cyclic coverings of degree 7

abstract:
  We study the Prym varieties arising from \'etale cyclic coverings of degree 7
over a curve of genus 2. These Prym varieties are products of Jacobians JY x JY
of genus 3 curves Y with polarization type D=(1,1,1,1,1,7). We describe the
fibers of the Prym map between the moduli space of such coverings and the
moduli space of abelian sixfolds with polarization type D, admitting an
automorphism of order 7.


title:
Cohomology of automorphism groups of free groups with twisted
  coefficients

abstract:
  We compute the groups $H^*(\mathrm{Aut}(F_n); M)$ and $H^*(\mathrm{Out}(F_n);
M)$ in a stable range, where $M$ is obtained by applying a Schur functor to
$H_\mathbb{Q}$ or $H^*_\mathbb{Q}$, respectively the first rational homology
and cohomology of $F_n$. For reasons which are not conceptually clear, taking
coefficients in $H_\mathbb{Q}$ and its related modules behaves in a far less
trivial way than taking coefficients in $H^*_\mathbb{Q}$ and its related
modules. The answer may be described in terms of stable multiplicities of
irreducibles in the plethysm $\mathrm{Sym}^k \circ \mathrm{Sym}^l$ of symmetric
powers.
  We also compute the stable integral cohomology groups of $\mathrm{Aut}(F_n)$
with coefficients in $H$ or $H^*$, respectively the first integral homology and
cohomology of $F_n$, and compute the stable cohomology with coefficients in
Schur functors of $H$ or $H^*$ modulo small primes.


title:
The (extended) dynamical mean field theory combined with the
  two-particle irreducible functional renormalization-group approach as a tool
  to study strongly-correlated systems

abstract:
  We propose new approach for treatment of local and non-local interactions in
correlated electronic systems, which uses self-energy and the two-particle
irreducible vertices, obtained from (extended) dynamical mean-field theory, as
an input of two-particle irreducible functional renormalization-group (2PI-fRG)
approach. Using 2PI-fRG approach allows us to treat both, local and non-local
interactions. In case of purely local interaction the corresponding equations
have similar (although not identical) structure to the earlier developed
DMF$^2$RG approach. In a simplest truncation, neglecting scale-dependence of
the two-particle irreducible vertices, we reproduce the results for the
two-particle vertices/susceptibilities in the ladder approximation of the dual
boson or D$\Gamma$A approach; in more sophisticated truncations the method
allows us to consider non-local corrections to the self-energy, as well as the
interplay of charge- and spin correlations. treatment of vertex
renormalizations. The proposed scheme is tested on the two-dimensional standard
and extended $U$-$V$ half-filled Hubbard models. For the standard Hubbard model
we obtain non-local self-energy, which is in agreement with numerical studies;
for the extended Hubbard model we obtain the boundary of charge instability,
which agrees well with the results of the dual boson (DB) approach. We also
find that the effect of spin correlations on electron interaction in the charge
channel, not considered previously in the DB approach, only slightly reduces
critical next-nearest-neighbor interaction of charge instability of the
extended Hubbard model at the considered finite small temperature, yielding
better agreement with dynamic cluster approximation. The considered method is
rather general and can be applied to study various phenomena in
strongly-correlated electronic systems.


title:
Quantum backaction and noise interference in asymmetric two-cavity
  optomechanical systems

abstract:
  We study the effect of cavity damping asymmetries on backaction in a
"membrane-in-the-middle" optomechanical system, where a mechanical mode
modulates the coupling between two photonic modes. We show that in the
adiabatic limit, this system generically realizes a dissipative optomechanical
coupling, with an effective position-dependent photonic damping rate. The
resulting quantum noise interference can be used to ground-state cool a
mechanical resonator in the unresolved sideband regime. We explicitly
demonstrate how quantum noise interference controls linear backaction effects,
and show that this interference persists even outside the adiabatic limit. For
a one-port cavity in the extreme bad-cavity limit, the interference allows one
to cancel all linear backaction effects. This allows continuous measurements of
position-squared, with no stringent constraints on the single-photon
optomechanical coupling strength. In contrast, such a complete cancellation is
not possible in the good cavity limit. This places strict bounds on the
optomechanical coupling required for quantum non-demolition measurements of
mechanical energy, even in a one-port device.


title:
A probabilistic approach to systems of parameters and Noether
  normalization

abstract:
  We study systems of parameters over finite fields from a probabilistic
perspective, and use this to give the first effective Noether normalization
result over a finite field. Our central technique is an adaptation of Poonen's
closed point sieve, where we sieve over higher dimensional subvarieties, and we
express the desired probabilities via a zeta function-like power series that
enumerates higher dimensional varieties instead of closed points. This also
yields a new proof of a recent result of Gabber-Liu-Lorenzini and
Chinburg-Moret-Bailly-Pappas-Taylor on Noether normalizations of projective
families over the integers.


title: Universal behavior of dense clusters of magnetic nanoparticles

abstract:
  A detailed numerical simulation of quasistatic hysteresis loops of dense
clusters of interacting magnetic nanoparticles is carried out. Both clusters of
magnetically soft and magnetically hard nanoparticles are considered. The
clusters are characterized by an average particle diameter D, the cluster
radius Rc, the particle saturation magnetization Ms, and the uniaxial
anisotropy constant K. The number of particles in the cluster varies between Np
= 30 - 120. The particle centers are randomly distributed within the cluster,
their easy anisotropy axes being randomly oriented. It is shown that a rare
assembly of identical random clusters of magnetic nanoparticles can be
characterized by two dimensionless parameters: 1) the relative strength of
magneto-dipole interaction, K/Ms^2, and the average particle concentration
within the cluster, {\eta} = VNp/Vc. Here V is the nanoparticle volume, and Vc
is the volume of the cluster, respectively. In the strong interaction limit,
Ms*{\eta}/Ha >> 1, where Ha = 2K/Ms is the anisotropy field, the ultimate
hysteresis loops of dilute assemblies of clusters have been constructed. In the
variables (M/Ms, H/Ms) these hysteresis loops depend only on the particle
volume fraction {\eta}. In the weak interaction limit, Ms*{\eta}/Ha << 1, the
assembly hysteresis loops in the variables (M/Ms, H/Ha) are close to the
standard Stoner-Wohlfarth hysteresis loop.


title: Electronic Evidence for Type II Weyl Semimetal State in MoTe2

abstract:
  Topological quantum materials, including topological insulators and
superconductors, Dirac semimetals and Weyl semimetals, have attracted much
attention recently for their unique electronic structure, spin texture and
physical properties. Very lately, a new type of Weyl semimetals has been
proposed where the Weyl Fermions emerge at the boundary between electron and
hole pockets in a new phase of matter, which is distinct from the standard type
I Weyl semimetals with a point-like Fermi surface. The Weyl cone in this type
II semimetals is strongly tilted and the related Fermi surface undergos a
Lifshitz transition, giving rise to a new kind of chiral anomaly and other new
physics. MoTe2 is proposed to be a candidate of a type II Weyl semimetal; the
sensitivity of its topological state to lattice constants and correlation also
makes it an ideal platform to explore possible topological phase transitions.
By performing laser-based angle-resolved photoemission (ARPES) measurements
with unprecedentedly high resolution, we have uncovered electronic evidence of
type II semimetal state in MoTe2. We have established a full picture of the
bulk electronic states and surface state for MoTe2 that are consistent with the
band structure calculations. A single branch of surface state is identified
that connects bulk hole pockets and bulk electron pockets. Detailed
temperature-dependent ARPES measurements show high intensity spot-like features
that is ~40 meV above the Fermi level and is close to the momentum space
consistent with the theoretical expectation of the type II Weyl points. Our
results constitute electronic evidence on the nature of the Weyl semimetal
state that favors the presence of two sets of type II Weyl points in MoTe2.


title:
Identifying two-dimensional $Z_2$ antiferromagnetic topological
  insulators

abstract:
  We revisit the question of whether a two-dimensional topological insulator
may arise in a commensurate N\'eel antiferromagnet, where staggered
magnetization breaks both the elementary translation and time reversal, but
retains their product as a symmetry. In contrast to the so-called $Z_2$
topological insulators, an exhaustive characterization of antiferromagnetic
topological phases with the help of a topological invariant has been missing.
We analyze a simple model of an antiferromagnetic topological insulator and
chart its phase diagram based on a recently proposed criterion for
centrosymmetric systems [Fang et al., Phys. Rev. B 88, 085406 (2013)]. We then
adapt two methods, originally designed for paramagnetic systems, and make
antiferromagnetic topological phases manifest. The proposed methods apply far
beyond the particular example treated in this work, and admit straightforward
generalization. We illustrate this by considering a non-centrosymmetric system,
where there are no simple criteria to identify topological phases. We also
present an explicit construction of edge states in an antiferromagnetic
topological insulator.


title:
Ponderomotive forces in electrodynamics of moving media: The Minkowski
  and Abraham approaches

abstract:
  In the general setting of the problem, the explicit compact formulae are
derived for the ponderomotive forces in the macroscopic electrodynamics of
moving media in the Minkowski and Abraham approaches. Taking account of the
Minkowski constitutive equations and making use of a special representation for
the Abraham energy-momentum tensor enable one to obtain a compact expression
for the Abraham force in the case of arbitrary dependence of the medium
velocity on spatial coordinates and the time and for nonstationary external
electromagnetic field. We term the difference between the ponderomotive forces
in the Abraham and Minkowski approaches as the Abraham force not only under
consideration of media at rest but also in the case of moving media. The
Lorentz force is found which is exerted by external electromagnetic field on
the conduction current in a medium, the covariant Ohm law and the constitutive
Minkowski relations being taken into account. The physical argumentation is
traced for definition of the 4-vector of the ponderomotive force as the
4-divergence of the energy-momentum tensor of electromagnetic field in a
medium.

categories: physics.class-ph cond-mat.mes-hall math-ph math.MP


title: High Temperature Effects on Compactlike Structures

abstract:
  In this work we investigate the transition from kinks to compactons at high
temperatures. We deal with a family of models, described by a real scalar field
with standard kinematics, controlled by a single parameter, real and positive.
The family of models supports kinklike solutions, and the solutions tend to
become compact when the parameter increases to larger and larger values. We
study the one-loop corrections at finite temperature, to see how the thermal
effects add to the effective potential. The results suggest that the symmetry
is restored at very high temperatures.


title:
Measurement of the double-beta decay half-life and search for the
  neutrinoless double-beta decay of $^{48}{\rm Ca}$ with the NEMO-3 detector

abstract:
  The NEMO-3 experiment at the Modane Underground Laboratory has investigated
the double-$\beta$ decay of $^{48}{\rm Ca}$. Using $5.25$ yr of data recorded
with a $6.99\,{\rm g}$ sample of $^{48}{\rm Ca}$, approximately $150$
double-$\beta$ decay candidate events have been selected with a
signal-to-background ratio greater than $3$. The half-life for the two-neutrino
double-$\beta$ decay of $^{48}{\rm Ca}$ has been measured to be
$T^{2\nu}_{1/2}\,=\,[6.4\, ^{+0.7}_{-0.6}{\rm (stat.)} \, ^{+1.2}_{-0.9}{\rm
(syst.)}] \times 10^{19}\,{\rm yr}$. A search for neutrinoless double-$\beta$
decay of $^{48}{\rm Ca}$ yields a null result and a corresponding lower limit
on the half-life is found to be $T^{0\nu}_{1/2} > 2.0 \times 10^{22}\,{\rm yr}$
at $90\%$ confidence level, translating into an upper limit on the effective
Majorana neutrino mass of $< m_{\beta\beta} > < 6.0 - 26$ ${\rm eV}$, with the
range reflecting different nuclear matrix element calculations. Limits are also
set on models involving Majoron emission and right-handed currents.


title:
The 750 GeV Resonance as Non-Minimally Coupled Inflaton: Unitarity
  Violation and Why the Resonance is a Real Singlet Scalar

abstract:
  The 750 GeV resonance observed by ATLAS and CMS may be explained by a gauge
singlet scalar. This would provide an ideal candidate for a gauge singlet
scalar alternative to Higgs Inflation, S-inflation. Here we discuss the
relevant results of S-inflation in the context of the 750 GeV resonance. In
particular, we show that a singlet scalar, if it is real, has a major advantage
over the Higgs boson with regard to unitarity violation during inflation. This
is because it is possible to restrict the large non-minimal coupling required
for inflation, $\xi \sim 10^5$, to the real singlet scalar, with all other
scalars having $\xi \sim 1$. In this case the scale of unitarity violation
$\Lambda$ is much larger than the inflaton field during inflation. This
protects the inflaton effective potential from modification by the new physics
or strong coupling which is necessary to restore unitarity, which would
otherwise invalidate the perturbative effective potential based on Standard
Model physics. This is in contrast to the case of Higgs Inflation or models
based on complex singlet scalars, where the unitarity violation scale during
inflation is less than or of the order of the inflaton field. Therefore if the
750 GeV resonance is the inflaton, it must be a non-minimally coupled real
singlet scalar.


title:
Magnetic structure, magnetoelastic coupling, and thermal properties of
  EuCrO$_3$ nano-powders

abstract:
  We carried out detailed studies of the magnetic structure, magnetoelastic
coupling, and thermal properties of EuCrO$_3$ nano-powders from room
temperature to liquid helium temperature. Our neutron powder diffraction and
X-ray powder diffraction measurements provide precise atomic positions of all
atoms in the cell, especially for the light oxygen atoms. The low-temperature
neutron powder diffraction data revealed extra Bragg peaks of magnetic origin
which can be attributed to a $G_x$ antiferromagnetic structure with an ordered
moment of $\sim$ 2.4 $\mu_{\rm B}$ consistent with the $3d^3$ electronic
configuration of the Cr$^{3+}$ cations. Apart from previously reported
antiferromagnetic and ferromagnetic transitions in EuCrO$_3$ at low
temperatures, we also observed an anomaly at about 100 K. This anomaly was
observed in temperature dependence of sample's, lattice parameters, thermal
expansion, Raman spectroscopy, permittivity and conductance measurements. This
anomaly is attributed to the magnetoelastic distortion in the EuCrO$_3$
crystal.


title:
A block Recycled GMRES method with investigations into aspects of solver
  performance

abstract:
  We propose a block Krylov subspace version of the GCRO-DR method proposed in
[Parks et al. SISC 2005], which is an iterative method allowing for the
efficient minimization of the the residual over an augmented block Krylov
subspace. We offer a clean derivation of the method and discuss methods of
selecting recycling subspaces at restart as well as implementation decisions in
the context of high-performance computing. Numerical experiments are split into
those demonstrating convergence properties and those demonstrating the data
movement and cache efficiencies of the dominant operations of the method,
measured using processor monitoring code from Intel.


title: Temperature Dependence of Angular Momentum Transport Across Interfaces

abstract:
  Angular momentum transport in magnetic multilayered structures plays a
central role in spintronic physics and devices. The angular momentum currents
or spin currents are carried by either quasi-particles such as electrons and
magnons, or by macroscopic order parameters such as local magnetization of
ferromagnets. Based on the generic interface exchange interaction, we develop a
microscopic theory that describes interfacial spin conductance for various
interfaces among non-magnetic metals, ferromagnetic and antiferromagnetic
insulators. Spin conductance and its temperature dependence are obtained for
different spin batteries including spin pumping, temperature gradient and spin
Hall effect. As an application of our theory, we calculate the spin current in
a trilayer made of a ferromagnetic insulator, an antiferromagnetic insulator
and a non-magnetic heavy metal. The calculated results on the temperature
dependence of spin conductance quantitatively agree with the existing
experiments.


title: A phylogenetic latent feature model for clonal deconvolution

abstract:
  Tumours develop in an evolutionary process, in which the accumulation of
mutations produces subpopulations of cells with distinct mutational profiles,
called clones. This process leads to the genetic heterogeneity widely observed
in tumour sequencing data, but identifying the genotypes and frequencies of the
different clones is still a major challenge. Here, we present Cloe, a
phylogenetic latent feature model to deconvolute tumour sequencing data into a
set of related genotypes. Our approach extends latent feature models by placing
the features as nodes in a latent tree. The resulting model can capture both
the acquisition and the loss of mutations, as well as episodes of convergent
evolution. We establish the validity of Cloe on synthetic data and assess its
performance on controlled biological data, comparing our reconstructions to
those of several published state-of-the-art methods. We show that our method
provides highly accurate reconstructions and identifies the number of clones,
their genotypes and frequencies even at a modest sequencing depth. As a proof
of concept we apply our model to clinical data from three cases with chronic
lymphocytic leukaemia, and one case with acute myeloid leukaemia.


title:
Positive tensor products of qubit maps and n-tensor-stable positive
  qubit maps

abstract:
  We analyze positivity of a tensor product of two linear qubit maps, $\Phi_1
\otimes \Phi_2$. Positivity of maps $\Phi_1$ and $\Phi_2$ is a necessary but
not a sufficient condition for positivity of $\Phi_1 \otimes \Phi_2$. We find a
non-trivial sufficient condition for positivity of the tensor product map
beyond the cases when both $\Phi_1$ and $\Phi_2$ are completely positive or
completely co-positive. We find necessary and (separately) sufficient
conditions for $n$-tensor-stable positive qubit maps, i.e. such qubit maps
$\Phi$ that $\Phi^{\otimes n}$ is positive. Particular cases of 2- and
3-tensor-stable positive qubit maps are fully characterized, and the
decomposability of 2-tensor-stable positive qubit maps is discussed. The case
of non-unital maps is reduced to the case of appropriate unital maps. Finally,
$n$-tensor-stable positive maps are used in characterization of multipartite
entanglement, namely, in the entanglement depth detection.


title:
Harmonic expansion of the effective potential in Functional
  Renormalization Group at finite chemical potential

abstract:
  In this paper we propose a method to study the Functional Renormalization
Group at finite chemical potential. The method consists of mapping the FRG
equations within the Fermi surface into a differential equation defined on a
rectangle with zero boundary conditions. To solve this equation we use an
expansion of the potential in a harmonic basis. With this method we determined
the phase diagram of a simple Yukawa-type model; as expected, the bosonic
fluctuations decrease the strength of the transition.


title:
Existence and stability of standing waves for nonlinear Schrodinger
  systems involving the fractional Laplacian

abstract:
  In the present paper we consider the coupled system of nonlinear
Schr\"{o}dinger equations with the fractional Laplacian \[ \left\{
\begin{aligned}
  (-\Delta)^\alpha u_1 & = \lambda_1u_1+f_1(u_1)+\partial_1F(u_1,u_2)\ \
\mathrm{in}\ \mathbb{R}^N, \\
  (-\Delta)^\alpha u_2 & = \lambda_2u_2+f_2(u_2)+\partial_2F(u_1,u_2)\ \
\mathrm{in}\ \mathbb{R}^N, \end{aligned} \right. \] where $u_1,
u_2:\mathbb{R}^N\to \mathbb{C},\ N\geq 2,$ and $0<\alpha<1.$ By studying an
appropriate family of constrained minimization problems, we obtain the
existence of solutions in the space $H^\alpha(\mathbb{R}^N) \times
H^\alpha(\mathbb{R}^N)$ satisfying \[ \int_{\mathbb{R}^N}|u_1|^2\ dx =
\sigma_1\ \ \textrm{and}\ \ \int_{\mathbb{R}^N}|u_2|^2\ dx=\sigma_2 \] for
given $\sigma_j>0.$ The numbers $\lambda_1$ and $\lambda_2$ in the system
appear as Lagrange multiplier. The method is based on the concentration
compactness arguments, but introduces a new way to verify some of the
properties of the variational problem that are required in order for the
concentration compactness method to work. We consider the case when
$f_j(s)=\mu_j|s|^{p_j-2}s$ and $F(s,t)=\beta |s|^{r_1}|t|^{r_2}$ with $\mu_j>0,
\beta>0,$ and the values $r_i>1, 2<p_j, r_1+r_2<2+\frac{4\alpha}{N}.$ The
method also enables us to prove the stability result of standing wave solutions
associated with the set of global minimizers.


title: Exorcising the Ostrogradsky ghost in coupled systems

abstract:
  The Ostrogradsky theorem implies that higher-derivative terms of a single
mechanical variable are either trivial or lead to additional, ghost-like
degrees of freedom. In this letter we systematically investigate how the
introduction of additional variables can remedy this situation. Employing a
Lagrangian analysis, we identify conditions on the Lagrangian to ensure the
existence of primary and secondary constraints that together imply the absence
of Ostrogradsky ghosts. We also show the implications of these conditions for
the structure of the equations of motion as well as possible redefinitions of
the variables. We discuss applications to analogous higher-derivative field
theories such as multi-Galileons and beyond Horndeski.


title:
Reading Between the Pixels: Photographic Steganography for Camera
  Display Messaging

abstract:
  We exploit human color metamers to send light-modulated messages less visible
to the human eye, but recoverable by cameras. These messages are a key
component to camera-display messaging, such as handheld smartphones capturing
information from electronic signage. Each color pixel in the display image is
modified by a particular color gradient vector. The challenge is to find the
color gradient that maximizes camera response, while minimizing human response.
The mismatch in human spectral and camera sensitivity curves creates an
opportunity for hidden messaging. Our approach does not require knowledge of
these sensitivity curves, instead we employ a data-driven method. We learn an
ellipsoidal partitioning of the six-dimensional space of colors and color
gradients. This partitioning creates metamer sets defined by the base color at
the display pixel and the color gradient direction for message encoding. We
sample from the resulting metamer sets to find color steps for each base color
to embed a binary message into an arbitrary image with reduced visible
artifacts. Unlike previous methods that rely on visually obtrusive intensity
modulation, we embed with color so that the message is more hidden. Ordinary
displays and cameras are used without the need for expensive LEDs or high speed
devices. The primary contribution of this work is a framework to map the pixels
in an arbitrary image to a metamer pair for steganographic photo messaging.


title:
N-block presentations and decidability of direct conjugacy between
  Subshifts of Finite Type

abstract:
  We consider the problem of inverting the transformation which consists in
replacing a word by the sequence of its blocks of length N, i.e. its so-called
N-block presentation. It was previously shown that among all the possible
preimages of an N-block presentation, there exists a particular one which is
maximal in the sense that all the other preimages can be obtained from it by
letter to letter applications. We give here a combinatorial characterization of
the maximal preimages of N-block presentations. Using this characterization, we
show that, being given two subshifts of finite type X and Y, the existence of
two numbers N and M such that the N-block presentation of X is similar to the
M-block presentation of Y, which implies that X and Y are conjugate, is
decidable.


title: CD-HPF: New Habitability Score Via Data Analytic Modeling

abstract:
  The search for life on the planets outside the Solar System can be broadly
classified into the following: looking for Earth-like conditions or the planets
similar to the Earth (Earth similarity), and looking for the possibility of
life in a form known or unknown to us (habitability). The two frequently used
indices, ESI and PHI, describe heuristic methods to score
similarity/habitability in the efforts to categorize different exoplanets or
exomoons. ESI, in particular, considers Earth as the reference frame for
habitability and is a quick screening tool to categorize and measure physical
similarity of any planetary body with the Earth. The PHI assesses the
probability that life in some form may exist on any given world, and is based
on the essential requirements of known life: a stable and protected substrate,
energy, appropriate chemistry and a liquid medium. We propose here a different
metric, a Cobb-Douglas Habitability Score (CDHS), based on Cobb-Douglas
habitability production function (CD-HPF), which computes the habitability
score by using measured and calculated planetary input parameters. The proposed
metric, with exponents accounting for metric elasticity, is endowed with
verifiable analytical properties that ensure global optima, and is scalable to
accommodate finitely many input parameters. The model is elastic, does not
suffer from curvature violations and, as we discovered, the standard PHI is a
special case of CDHS. Computed CDHS scores are fed to K-NN (K-Nearest
Neighbour) classification algorithm with probabilistic herding that facilitates
the assignment of exoplanets to appropriate classes via supervised feature
learning methods, producing granular clusters of habitability. The proposed
work describes a decision-theoretical model using the power of convex
optimization and algorithmic machine learning.


title: Postorder Preimages

abstract:
  Given a set $Y$ of decreasing plane trees and a permutation $\pi$, how many
trees in $Y$ have $\pi$ as their postorder? Using combinatorial and geometric
constructions, we provide a method for answering this question for certain sets
$Y$ and all permutations $\pi$. We then provide applications of our results to
the study of the deterministic stack-sorting algorithm.


title:
Some remarks about the weak containment property for groupoids and
  semigroups

abstract:
  A locally compact groupoid is said to have the weak containment property if
its full $C^*$-algebra coincides with its reduced one. This property is
strictly weaker than amenability and is known to be equivalent to amenability
for transformation groupoids relative to actions of exact discrete groups. We
believe that for general \'etale groupoids one should have the same equivalence
of the two properties under some mild exactness assumption. In this paper we
try to support this statement.


title:
Fractional Lattice Dynamics: Nonlocal constitutive behavior generated by
  power law matrix functions and their fractional continuum limit kernels

abstract:
  We introduce positive elastic potentials in the harmonic approximation
leading by Hamilton's variational principle to fractional Laplacian matrices
having the forms of power law matrix functions of the simple local Bornvon
Karman Laplacian. The fractional Laplacian matrices are well defined on
periodic and infinite lattices in $n=1,2,3,..$ dimensions. The present approach
generalizes the central symmetric second differenceoperator (Born von Karman
Laplacian) to its fractional central symmetric counterpart (Fractional
Laplacian matrix).For non-integer powers of the Born von Karman Laplacian, the
fractional Laplacian matrix is nondiagonal with nonzero matrix elements
everywhere, corresponding to nonlocal behavior: For large lattices the matrix
elements far from the diagonal expose power law asymptotics leading to
continuum limit kernels of Riesz fractional derivative type. We present
explicit results for the fractional Laplacian matrix in 1D for finite periodic
and infinite linear chains and their Riesz fractional derivative continuum
limit kernels.The approach recovers for $\alpha=2$ the well known classical
Born von Karman linear chain (1D lattice) with local next neighbor
springsleading in the well known continuum limit of classic local standard
elasticity, and for other integer powers to gradient elasticity.We also present
a generalization of the fractional Laplacian matrix to n-dimensional cubic
periodic (nD tori) and infinite lattices. For the infinite nD lattice we
deducea convenient integral representation.We demonstrate that our fractional
lattice approach is a powerful tool to generate physically admissible nonlocal
lattice material models and their continuum representations.


title: Statistical properties of Fourier-based time-lag estimates

abstract:
  The study of X-ray time-lag spectra in active galactic nuclei (AGN) is
currently an active research area, since it has the potential to illuminate the
physics and geometry of the innermost region (i.e. close to the putative
super-massive black hole) in these objects. To obtain reliable information from
these studies, the statistical properties of time-lags estimated from data must
be known as accurately as possible.
  Aims: We investigated the statistical properties of Fourier-based time-lag
estimates (i.e. based on the cross-periodogram), using evenly sampled time
series with no missing points. Our aim is to provide practical `guidelines' on
estimating time-lags that are minimally biased (i.e. whose mean is close to
their intrinsic value) and have known errors.}
  Methods: Our investigation is based on both analytical work and extensive
numerical simulations. The latter consisted of generating artificial time
series with various signal-to-noise ratios and sampling patterns/durations
similar to those offered by AGN observations with present and past X-ray
satellites. We also considered a range of different model time-lag spectra
commonly assumed in X-ray analyses of compact accreting systems.
  Results: Discrete sampling, binning and finite light curve duration cause the
mean of the time-lag estimates to have a smaller magnitude than their intrinsic
values. Smoothing (i.e. binning over consecutive frequencies) of the
cross-periodogram can add extra bias at low frequencies. The use of light
curves with low signal-to-noise ratio reduces the intrinsic coherence, and can
introduce a bias to the sample coherence, time-lag estimates, and their
predicted error.


title:
One-dimensional parametric determining form for the two-dimensional
  Navier-Stokes equations

abstract:
  The evolution of a determining form for the 2D Navier-Stokes equations (NSE),
which is an ODE on a space of trajectories is completely described. It is
proved that at every stage of its evolution, the solution is a convex
combination of the initial trajectory and the fixed steady state, with a
dynamical convexity parameter $\theta$, which will be called the characteristic
determining parameter. That is, we show a remarkable separation of variables
formula for the solution of the determining form. Moreover, for a given initial
trajectory, the dynamics of the infinite-dimensional determining form are
equivalent to those of the characteristic determining parameter $\theta$ which
is governed by a one-dimensional ODE. %for the parameter specifying the
position on the line segment. This one-dimensional ODE is used to show that if
the solution to the determining form converges to the fixed state it does so no
faster than $\mathcal{O}(\tau^{-1/2})$, otherwise it converges to a projection
of some other trajectory in the global attractor of the NSE, but no faster than
$\mathcal{O}(\tau^{-1})$, as $\tau \to \infty$, where $\tau$ is the
evolutionary variable in determining form. The one-dimensional ODE also
exploited in computations which suggest that the one-sided convergence rate
estimates are in fact achieved. The ODE is then modified to accelerate the
convergence to an exponential rate. Remarkably, it is shown that the zeros of
the scalar function that governs the dynamics of $\theta$, which are called
characteristic determining values, identify in a unique fashion the
trajectories in the global attractor of the 2D NSE. Furthermore, the
one-dimensional characteristic determining form enables us to find
unanticipated geometric features of the global attractor, a subject of future
research.


title:
Evidence for neutral-current diffractive neutral pion production from
  hydrogen in neutrino interactions on hydrocarbon

abstract:
  The MINERvA experiment observes an excess of events containing
electromagnetic showers relative to the expectation from Monte Carlo
simulations in neutral-current neutrino interactions with mean beam energy of
4.5 GeV on a hydrocarbon target. The excess is characterized and found to be
consistent with neutral-current neutral pion production with a broad energy
distribution peaking at 7 GeV and a total cross section of 0.26 +- 0.02 (stat)
+- 0.08 (sys) x 10^{-39} cm^{2}. The angular distribution, electromagnetic
shower energy, and spatial distribution of the energy depositions of the excess
are consistent with expectations from neutrino neutral-current diffractive
neutral pion production from hydrogen in the hydrocarbon target. These data
comprise the first direct experimental observation and constraint for a
reaction that poses an important background process in neutrino oscillation
experiments searching for muon neutrino to electron neutrino oscillations.


title:
Improving LSTM-based Video Description with Linguistic Knowledge Mined
  from Text

abstract:
  This paper investigates how linguistic knowledge mined from large text
corpora can aid the generation of natural language descriptions of videos.
Specifically, we integrate both a neural language model and distributional
semantics trained on large text corpora into a recent LSTM-based architecture
for video description. We evaluate our approach on a collection of Youtube
videos as well as two large movie description datasets showing significant
improvements in grammaticality while modestly improving descriptive quality.


title:
Homogeneous one-dimensional Bose-Einstein Condensate in the Bogoliubov's
  Regime

abstract:
  We analyze the corrections caused by finite size effects upon the ground
state properties of a homogeneous one-dimensional Bose-Einstein condensate. We
assume from the very beginning that the Bogoliubov's formalism is valid and
consequently we show that in order to obtain a well defined ground state
properties, finite size effects of the system must be taken into account.
Indeed, the formalism described in the present work allows to recover the usual
properties related to the ground state of a homogeneous one-dimensional
Bose-Einstein condensate but corrected by finite size effects of the system.
Finally, this scenario allows us to analyze the sensitivity of the system when
the Bogoliubov's regime is valid and when finite size effects are present.
These facts open the possibility to apply these ideas to more realistic
scenarios, e.g., low-dimensional trapped Bose-Einstein condensates.


title: B_c^+- decays into tetraquarks

abstract:
  The recent observation by the D0 collaboration of a narrow structure X(5568)
consisting of four different quark flavors bdus, has not been confirmed by
LHCb. More data and dedicated analyses are needed to cover a larger mass range.
In the tightly bound diquark model, we estimate the lightest bdus, 0^+
tetraquark at a mass of about 5770 MeV, approximately 200 MeV above the
reported X(5568), and just 7 MeV below the B Kbar threshold. The charged
tetraquark is accompanied by I=1 and I=0 neutral partners almost degenerate in
mass. A bdus, S-wave, 1^+ quartet at 5820 MeV is implied as well. In the charm
sector, cdus, 0^+ and 1^+ tetraquarks are predicted at 2365 MeV and 2501 MeV,
about 40-50 MeV heavier than D_{s0}(2317) and D_{s1}(2460). bdus tetraquarks
can be searched in the hadronic debris of a jet initiated by a b. However, some
of them may also be produced in B_c decays. The proposed discovery modes of
S-wave tetraquarks are B_c --> X_{b0} + pi with the subsequent decays X_{b0}
--> B_s + pi, giving rise to final states such as B_s pi^+ pi^0. We also
emphasize the importance of B_c decays as a source of bound hidden charm
tetraquarks, such as B_c --> X(3872) + pi.


title: Topological Resonances on Quantum Graphs

abstract:
  In this paper, we try to put the results of Smilansky and al. on "Topological
resonances" on a mathematical basis.A key role in the asymptotic of resonances
near the real axis for Quantum Graphs is played by the set of metrics for which
there exists compactly supported eigenfunctions. We give several estimateof the
dimension of this semi-algebraic set, in particular in terms of the girth of
the graph. The case oftrees is also discussed.


title:
A U-statistic Approach to Hypothesis Testing for Structure Discovery in
  Undirected Graphical Models

abstract:
  Structure discovery in graphical models is the determination of the topology
of a graph that encodes conditional independence properties of the joint
distribution of all variables in the model. For some class of probability
distributions, an edge between two variables is present if and only if the
corresponding entry in the precision matrix is non-zero. For a finite sample
estimate of the precision matrix, entries close to zero may be due to low
sample effects, or due to an actual association between variables; these two
cases are not readily distinguishable. %Fisher provided a hypothesis test based
on a parametric approximation to the distribution of an entry in the precision
matrix of a Gaussian distribution, but this may not provide valid upper bounds
on $p$-values for non-Gaussian distributions. Many related works on this topic
consider potentially restrictive distributional or sparsity assumptions that
may not apply to a data sample of interest, and direct estimation of the
uncertainty of an estimate of the precision matrix for general distributions
remains challenging. Consequently, we make use of results for $U$-statistics
and apply them to the covariance matrix. By probabilistically bounding the
distortion of the covariance matrix, we can apply Weyl's theorem to bound the
distortion of the precision matrix, yielding a conservative, but sound test
threshold for a much wider class of distributions than considered in previous
works. The resulting test enables one to answer with statistical significance
whether an edge is present in the graph, and convergence results are known for
a wide range of distributions. The computational complexities is linear in the
sample size enabling the application of the test to large data samples for
which computation time becomes a limiting factor. We experimentally validate
the correctness and scalability of the test on multivariate distributions for
which the distributional assumptions of competing tests result in
underestimates of the false positive ratio. By contrast, the proposed test
remains sound, promising to be a useful tool for hypothesis testing for diverse
real-world problems.


title:
Efficiency and Sequenceability in Fair Division of Indivisible Goods
  with Additive Preferences

abstract:
  In fair division of indivisible goods, using sequences of sincere choices (or
picking sequences) is a natural way to allocate the objects. The idea is the
following: at each stage, a designated agent picks one object among those that
remain. This paper, restricted to the case where the agents have numerical
additive preferences over objects, revisits to some extent the seminal paper by
Brams and King [9] which was specific to ordinal and linear order preferences
over items. We point out similarities and differences with this latter context.
In particular, we show that any Pareto-optimal allocation (under additive
preferences) is sequenceable, but that the converse is not true anymore. This
asymmetry leads naturally to the definition of a "scale of efficiency" having
three steps: Pareto-optimality, sequenceability without Pareto-optimality, and
non-sequenceability. Finally, we investigate the links between these efficiency
properties and the "scale of fairness" we have described in an earlier work
[7]: we first show that an allocation can be envy-free and non-sequenceable,
but that every competitive equilibrium with equal incomes is sequenceable. Then
we experimentally explore the links between the scales of efficiency and
fairness.


title:
Plasma-screening effects on the electronic structure of multiply charged
  Al ions using Debye and ionsphere models

abstract:
  We analyze atomic structures of plasma embedded aluminum (Al) atom and its
ions in the weakly and strongly coupling regimes. The plasma screening effects
in these atomic systems are accounted for using the Debye and ion sphere (IS)
potentials for the weakly coupling and strongly coupling plasmas, respectively.
Within the Debye model, special attention is given to investigate the spherical
and non-spherical plasma-screening effects considering in the electron-electron
interaction potential. The relativistic coupled-cluster (RCC) method has been
employed to describe the relativistic and electronic correlation effects in the
above atomic systems. The variation in the ionization potentials (IPs) and
excitation energies (EEs) of the plasma embedded Al ions are presented. It is
found that the atomic systems exhibit more stability when the exact screening
effects are taken into account. It is also showed that in the presence of
strongly coupled plasma environment, the highly ionized Al ions show blue and
red shifts in the spectral lines of the transitions between the states with
same and different principal quantum numbers, respectively. Comparison among
the results obtained from the Debye and IS models are also carried out
considering similar plasma conditions.


title:
Deterministic radiative coupling between plasmonic nanoantennas and
  semiconducting nanowire quantum dots

abstract:
  We report on the deterministic coupling between single semiconducting
nanowire quantum dots emitting in the visible and plasmonic Au nanoantennas.
Both systems are separately carefully characterized through
microphotoluminescence and cathodoluminescence. A two-step realignment process
using cathodoluminescence allows for electron beam lithography of Au antennas
near individual nanowire quantum dots with a precision of 50 nm. A complete set
of optical properties are measured before and after antenna fabrication. They
evidence both an increase of the NW absorption, and an improvement of the
quantum dot emission rate up to a factor two in presence of the antenna.


title:
Comment on '[N(CH3)3H]2ZnCl4: Ferroelectric properties and
  characterization of phase transitions by Raman spectroscopy'

abstract:
  The authors of paper commented claim that trimethylammonium
tetrachlorozincate crystal shows at 282 K the ferroelectric-paraelectric phase
transition. But no ferroelectric hysteresis loop was observed below this
temperature. Moreover, in the low-temperature phase the ferroelectric domain
walls should exist giving dielectric relaxation in a low frequency electric
field. The authors conclude that the phase transition is of the second order.
This conclusion is contrary to the DSC data where the phase transition has a
strong first order character. In the whole measured temperature range the
dielectric loss is 100 times higher than the real part of dielectric constant.


title:
A large time-step and well-balanced Lagrange-Projection type scheme for
  the shallow-water equations

abstract:
  This work focuses on the numerical approximation of the Shallow Water
Equations (SWE) using a Lagrange-Projection type approach. We propose to extend
to this context recent implicit-explicit schemes developed in the framework of
compressibleflows, with or without stiff source terms. These methods enable the
use of time steps that are no longer constrained by the sound velocity thanks
to an implicit treatment of the acoustic waves, and maintain accuracy in the
subsonic regime thanks to an explicit treatment of the material waves. In the
present setting, a particular attention will be also given to the
discretization of the non-conservative terms in SWE and more specifically to
the well-known well-balanced property. We prove that the proposed numerical
strategy enjoys important non linear stability properties and we illustrate its
behaviour past several relevant test cases.


title:
Towards Service-oriented 5G: Virtualizing the Networks for
  Everything-as-a-Service

abstract:
  It is widely acknowledged that the forthcoming 5G architecture will be highly
heterogeneous and deployed with a high degree of density. These changes over
the current 4G bring many challenges on how to achieve an efficient operation
from the network management perspective. In this article, we introduce a
revolutionary vision of the future 5G wireless networks, in which the network
is no longer limited by hardware or even software. Specifically, by the idea of
virtualizing the wireless networks, which has recently gained increasing
attention, we introduce the Everything-as-a-Service (XaaS) taxonomy to light
the way towards designing the service-oriented wireless networks. The concepts,
challenges along with the research opportunities for realizing XaaS in wireless
networks are overviewed and discussed.


title: Multiple network alignment via multiMAGNA++

abstract:
  Network alignment (NA) aims to find a node mapping between molecular networks
of different species that identifies topologically or functionally similar
network regions. Analogous to genomic sequence alignment, NA can be used to
transfer biological knowledge from well- to poorly-studied species between
aligned network regions. Pairwise NA (PNA) finds similar regions between two
networks while multiple NA (MNA) can align more than two networks. We focus on
MNA. Existing MNA methods aim to maximize total similarity over all aligned
nodes (node conservation). Then, they evaluate alignment quality by measuring
the amount of conserved edges, but only after the alignment is constructed.
Directly optimizing edge conservation during alignment construction in addition
to node conservation may result in superior alignments. Thus, we present a
novel MNA approach called multiMAGNA++ that can achieve this. Indeed,
multiMAGNA++ generally outperforms or is on par with the existing MNA methods,
while often completing faster than the existing methods. That is, multiMAGNA++
scales well to larger network data and can be parallelized effectively. During
method evaluation, we also introduce new MNA quality measures to allow for more
complete alignment characterization as well as more fair MNA method comparison
compared to using only the existing alignment quality measures.


title:
Cournot-Nash Equilibria for Bandwidth Allocation under Base-Station
  Cooperation

abstract:
  -In this paper, a novel resource allocation scheme based on discrete
Cournot-Nash equilibria and optimal transport theory is proposed. The
originality of this framework lies in the joint optimization of downlink
bandwidth allocation and cooperation between base stations. A tractable
formalization is given in the form of a quadratic optimization problem. A low
complexity approximate solution is derived and theoretically characterized.
Simulations highlight the existence of an optimal working point, that maximizes
user satisfaction ratio and network load. The impact of the network deployment
on the optimum is numerically investigated, thanks to the $\beta$-Ginibre
model. Indeed, base stations are assumed to be drawn according to
$\beta$-Ginibre point processes. Numerical analysis shows that the network
performance increases with $\beta$ going to one.


title:
Indo-Pacific variability on seasonal to multidecadal timescales. Part I:
  Intrinsic SST modes in models and observations

abstract:
  The variability of Indo-Pacific SST on seasonal to multidecadal timescales is
investigated using a recently introduced technique called nonlinear Laplacian
spectral analysis (NLSA). Through this technique, drawbacks associated with ad
hoc pre-filtering of the input data are avoided, enabling recovery of
low-frequency and intermittent modes not previously accessible via classical
approaches. Here, a multiscale hierarchy of spatiotemporal modes is identified
for Indo-Pacific SST in millennial control runs of CCSM4 and CM3 and in HadISST
data. On interannual timescales, a mode with spatiotemporal patterns
corresponding to the fundamental component of ENSO emerges, along with
ENSO-modulated annual modes consistent with combination mode theory. The ENSO
combination modes also feature prominent activity in the Indian Ocean,
explaining significant fraction of the SST variance in regions associated with
the Indian Ocean dipole. A pattern resembling the tropospheric biennial
oscillation emerges in addition to ENSO and the associated combination modes.
On multidecadal timescales, the dominant NLSA mode in the model data is
predominantly active in the western tropical Pacific. The interdecadal Pacific
oscillation also emerges as a distinct NLSA mode, though with smaller explained
variance than the western Pacific multidecadal mode. Analogous modes on
interannual and decadal timescales are also identified in HadISST data for the
industrial era, as well as in model data of comparable timespan, though decadal
modes are either absent or of degraded quality in these datasets.


title:
Lower Bounds and the Asymptotic Behaviour of Positive Operator
  Semigroups

abstract:
  If $(T_t)$ is a semigroup of Markov operators on an $L^1$-space that admits a
non-trivial lower bound, then a well-known theorem of Lasota and Yorke asserts
that the semigroup is strongly convergent as $t \to \infty$. In this article we
generalise and improve this result in several respects.
  First, we give a new and very simple proof for the fact that the same
conclusion also holds if the semigroup is merely assumed to be bounded instead
of Markov. As a main result we then prove a version of this theorem for
semigroups which only admit certain individual lower bounds. Moreover, we
generalise a theorem of Ding on semigroups of Frobenius-Perron operators. We
also demonstrate how our results can be adapted to the setting of general
Banach lattices and we give some counterexamples to show optimality of our
results.
  Our methods combine some rather concrete estimates and approximation
arguments with abstract functional analytical tools. One of these tools is a
theorem which relates the convergence of a time-continuous operator semigroup
to the convergence of embedded discrete semigroups.


title:
The effect of $^{22}$Ne diffusion in the evolution and pulsational
  properties of white dwarfs with solar metallicity progenitors

abstract:
  Because of the large neutron excess of $^{22}$Ne, this isotope rapidly
sediments in the interior of the white dwarfs. This process releases an
additional amount of energy, thus delaying the cooling times of the white
dwarf. This influences the ages of different stellar populations derived using
white dwarf cosmochronology. Furthermore, the overabundance of $^{22}$Ne in the
inner regions of the star, modifies the Brunt-V\"ais\"al\"a frequency, thus
altering the pulsational properties of these stars. In this work, we discuss
the impact of $^{22}$Ne sedimentation in white dwarfs resulting from Solar
metallicity progenitors ($Z=0.02$). We performed evolutionary calculations of
white dwarfs of masses $0.528$, $0.576$, $0.657$ and $0.833$ M$_{\sun}$,
derived from full evolutionary computations of their progenitor stars, starting
at the Zero Age Main Sequence all the way through central hydrogen and helium
burning, thermally-pulsing AGB and post-AGB phases. Our computations show that
at low luminosities ($\log(L/L_{\sun})\la -4.25$), $^{22}$Ne sedimentation
delays the cooling of white dwarfs with Solar metallicity progenitors by about
1~Gyr. Additionally, we studied the consequences of $^{22}$Ne sedimentation on
the pulsational properties of ZZ~Ceti white dwarfs. We find that $^{22}$Ne
sedimentation induces differences in the periods of these stars larger than the
present observational uncertainties, particularly in more massive white dwarfs.

categories: astro-ph.SR astro-ph.GA cond-mat.stat-mech nucl-th


title: Distributed Synthesis of State-Dependent Switching Control

abstract:
  We present a correct-by-design method of state-dependent control synthesis
for linear discrete-time switching systems. Given an objective region R of the
state space, the method builds a capture set S and a control which steers any
element of S into R. The method works by iterated backward reachability from R.
More precisely, S is given as a parametric extension of R, and the maximum
value of the parameter is solved by linear programming. The method can also be
used to synthesize a stability control which maintains indefinitely within R
all the states starting at R. We explain how the synthesis method can be
performed in a distributed manner. The method has been implemented and
successfully applied to the synthesis of a distributed control of a concrete
floor heating system with 11 rooms and 2^11 = 2048 switching modes.


title:
Strengths and weaknesses of weak-strong cluster problems: A detailed
  overview of state-of-the-art classical heuristics vs quantum approaches

abstract:
  To date, a conclusive detection of quantum speedup remains elusive. Recently,
a team by Google Inc.~[V.~S.~Denchev {\em et al}., Phys.~Rev.~X {\bf 6}, 031015
(2016)] proposed a weak-strong cluster model tailored to have tall and narrow
energy barriers separating local minima, with the aim to highlight the value of
finite-range tunneling. More precisely, results from quantum Monte Carlo
simulations, as well as the D-Wave 2X quantum annealer scale considerably
better than state-of-the-art simulated annealing simulations. Moreover, the
D-Wave 2X quantum annealer is $\sim 10^8$ times faster than simulated annealing
on conventional computer hardware for problems with approximately $10^3$
variables. Here, an overview of different sequential, nontailored, as well as
specialized tailored algorithms on the Google instances is given. We show that
the quantum speedup is limited to sequential approaches and study the typical
complexity of the benchmark problems using insights from the study of spin
glasses.


title:
Symmetrization of exterior parabolic problems and probabilistic
  interpretation

abstract:
  We prove a comparison theorem for the averages of the solutions of two
exterior parabolic problems, the second being the "symmetrization" of the first
one, by using approximation of the Schwarz symmetrization by polarizations, as
it was introduced in [4]. This comparison provides an alternative proof, based
on PDEs, of the isoperimetric inequality for the Wiener sausage, which was
proved in [14].


title: Gorenstein and Totally Reflexive Orders

abstract:
  In this paper we study orders over Cohen-Macaulay rings. We discuss desirable
properties for these orders if they are to represent NCCRs of the base rings.
While some definitions have been made, we discuss an alternate definition and
the non-existence of examples. We then give necessary and sufficient conditions
for an order to have certain desirable homological properties. We examine
examples of rings satisfying these properties to prove that certain
endormorphism rings over abelian quotient singularities have infinite global
dimension.


title:
Quantum Wigner molecules in semiconductor quantum dots and cold-atom
  optical traps and their mathematical symmetries

abstract:
  Strong repelling interactions between a few fermions or bosons confined in
two-dimensional circular traps lead to particle localization and formation of
quantum Wigner molecules (QWMs) possessing definite point-group space
symmetries. These point-group symmetries are "hidden" (or emergent), namely
they cannot be traced in the circular single-particle densities (SPDs)
associated with the exact many-body wave functions, but they are manifested as
characteristic signatures in the ro-vibrational spectra. An example, among
many, are the few-body QWM states under a high magnetic field or at fast
rotation, which are precursor states for the fractional quantum Hall effect.
The hidden geometric symmetries can be directly revealed by using spin-resolved
conditional probability distributions, which are extracted from
configuration-interaction (CI), exact-diagonalization wave functions. The
hidden symmetries can also be revealed in the CI SPDs by reducing the symmetry
of the trap (from circular to elliptic to quasi-linear). In addition the hidden
symmetries are directly connected to the explicitly broken-symmetry (BS)
solutions of mean-field approaches, such as unrestricted Hartree-Fock (UHF). A
companion step of restoration of the broken symmetries via projection operators
applied on the BS-UHF solutions produces wave functions directly comparable to
the CI ones, and sheds further light into the role played by the emergence of
hidden symmetries in the exact many-body wave functions. Illustrative examples
of the importance of hidden symmetries in the many-body problem of few
electrons in semiconductor quantum dots and of few ultracold atoms in optical
traps (where unprecedented control of the interparticle interaction has been
experimentally achieved recently) will be presented.

categories: cond-mat.mes-hall cond-mat.quant-gas nucl-th quant-ph


title:
An explicit bound for the least prime ideal in the Chebotarev density
  theorem

abstract:
  We prove an explicit version of Weiss' bound on the least norm of a prime
ideal in the Chebotarev density theorem, which is itself a significant
improvement on the work of Lagarias, Montgomery, and Odlyzko. In order to
accomplish this, we prove an explicit log-free zero density estimate and an
explicit version of the zero-repulsion phenomenon for Hecke $L$-functions. As
an application, we prove the first explicit nontrivial upper bound for the
least prime represented by a positive-definite primitive binary quadratic form.
We also present applications to the group of $\mathbb{F}_p$-rational points of
an elliptic curve and congruences for the Fourier coefficients of holomorphic
cuspidal modular forms.


title: Spatio-temporal optical vortices

abstract:
  We present the first experimental evidence, supported by theory and
simulation, of spatiotemporal optical vortices (STOVs). Quantized STOVs are a
fundamental element of the nonlinear collapse and subsequent propagation of
short optical pulses in material media. A STOV consists of a ring-shaped null
in the electromagnetic field about which the phase is spiral, forming a dynamic
torus which is concentric with and tracks the propagating pulse. Depending on
the sign of the material dispersion, the local electromagnetic energy flow is
saddle or spiral about the STOV. STOVs are born and evolve conserving
topological charge; they can be simultaneously created in pairs with opposite
windings, or generated from a point null. Our results, here obtained for
optical pulse collapse and filamentation in air, are generalizable to broad
class of nonlinearly propagating waves.


title:
Large-$N$ Pion Scattering, Finite-Temperature Effects and the
  Relationship of the $f_{0}(500)$ with Chiral Symmetry Restoration

abstract:
  In this work, we review how the mass and the width of the $f_{0}(500)$ pole
behave in a regime where temperature is below the critical chiral transition
value. This is attained by considering a large-$N$ $O(N + 1)/O(N)$ invariant
Non-Linear Sigma Model (NLSM) such that we can study the dynamical generation
of a $f_{0}(500)$ resonance. Introducing thermal effects via the imaginary time
formalism allows us to study the behavior of the pole and relate it to chiral
restoration.


title:
Hollywood in Homes: Crowdsourcing Data Collection for Activity
  Understanding

abstract:
  Computer vision has a great potential to help our daily lives by searching
for lost keys, watering flowers or reminding us to take a pill. To succeed with
such tasks, computer vision methods need to be trained from real and diverse
examples of our daily dynamic scenes. While most of such scenes are not
particularly exciting, they typically do not appear on YouTube, in movies or TV
broadcasts. So how do we collect sufficiently many diverse but boring samples
representing our lives? We propose a novel Hollywood in Homes approach to
collect such data. Instead of shooting videos in the lab, we ensure diversity
by distributing and crowdsourcing the whole process of video creation from
script writing to video recording and annotation. Following this procedure we
collect a new dataset, Charades, with hundreds of people recording videos in
their own homes, acting out casual everyday activities. The dataset is composed
of 9,848 annotated videos with an average length of 30 seconds, showing
activities of 267 people from three continents. Each video is annotated by
multiple free-text descriptions, action labels, action intervals and classes of
interacted objects. In total, Charades provides 27,847 video descriptions,
66,500 temporally localized intervals for 157 action classes and 41,104 labels
for 46 object classes. Using this rich data, we evaluate and provide baseline
results for several tasks including action recognition and automatic
description generation. We believe that the realism, diversity, and casual
nature of this dataset will present unique challenges and new opportunities for
computer vision community.