title:
Quantum engines and the range of the second law of thermodynamics in the
  noncommutative phase-space

abstract:
  Two testable schemes for quantum heat engines are investigated under the
quantization framework of noncommutative (NC) quantum mechanics (QM). By
identifying the phenomenological connection between the phase-space NC driving
parameters and an effective external magnetic field, the NC effects on the
efficiency coefficient, \mathcal{N} , of quantum engines can be quantified for
two different cycles: an isomagnetic one and an isoenergetic one. In addition,
paying a special attention to the quantum Carnot cycle, one notices that the
inclusion of NC effects does not affect the maximal (Carnot) efficiency,
\mathcal{N}^C, ratifying the robustness of the second law of thermodynamics.


title: Introspective Agents: Confidence Measures for General Value Functions

abstract:
  Agents of general intelligence deployed in real-world scenarios must adapt to
ever-changing environmental conditions. While such adaptive agents may leverage
engineered knowledge, they will require the capacity to construct and evaluate
knowledge themselves from their own experience in a bottom-up, constructivist
fashion. This position paper builds on the idea of encoding knowledge as
temporally extended predictions through the use of general value functions.
Prior work has focused on learning predictions about externally derived signals
about a task or environment (e.g. battery level, joint position). Here we
advocate that the agent should also predict internally generated signals
regarding its own learning process - for example, an agent's confidence in its
learned predictions. Finally, we suggest how such information would be
beneficial in creating an introspective agent that is able to learn to make
good decisions in a complex, changing world.


title: Reconstructing plane quartics from their invariants

abstract:
  We present an explicit method that, given a generic tuple of Dixmier-Ohno
invariants, reconstructs a corresponding plane quartic curve.


title:
Structure and dynamics of binary liquid mixtures near their continuous
  demixing transitions

abstract:
  The dynamic and static critical behavior of five binary Lennard-Jones liquid
mixtures, close to their continuous demixing points (belonging to the so-called
model H' dynamic universality class), are studied computationally by combining
semi-grand canonical Monte Carlo simulations and large-scale molecular dynamics
(MD) simulations, accelerated by graphic processing units (GPU). The symmetric
binary liquid mixtures considered cover a variety of densities, a wide range of
compressibilities, and various interactions between the unlike particles. The
static quantities studied here encompass the bulk phase diagram (including both
the binodal and the $\lambda$-line), the correlation length, the concentration
susceptibility, the compressibility of the finite-sized systems at the bulk
critical temperature $T_c$, and the pressure. Concerning the collective
transport properties, we focus on the Onsager coefficient and the shear
viscosity. The critical power-law singularities of these quantities are
analyzed in the mixed phase (above $T_c$) and non-universal critical amplitudes
are extracted. Two universal amplitude ratios are calculated. The first one
involves static amplitudes only and agrees well with the expectations for the
three-dimensional Ising universality class. The second ratio includes also
dynamic critical amplitudes and is related to the Einstein--Kawasaki relation
for the interdiffusion constant. Precise estimates of this amplitude ratio are
difficult to obtain from MD simulations, but within the error bars our results
are compatible with theoretical predictions and experimental values for model
H'. Evidence is reported for an inverse proportionality of the pressure and the
isothermal compressibility at the demixing transition, upon varying either the
number density or the repulsion strength between unlike particles.


title: Ground Truth Bias in External Cluster Validity Indices

abstract:
  It has been noticed that some external CVIs exhibit a preferential bias
towards a larger or smaller number of clusters which is monotonic (directly or
inversely) in the number of clusters in candidate partitions. This type of bias
is caused by the functional form of the CVI model. For example, the popular
Rand index (RI) exhibits a monotone increasing (NCinc) bias, while the Jaccard
Index (JI) index suffers from a monotone decreasing (NCdec) bias. This type of
bias has been previously recognized in the literature. In this work, we
identify a new type of bias arising from the distribution of the ground truth
(reference) partition against which candidate partitions are compared. We call
this new type of bias ground truth (GT) bias. This type of bias occurs if a
change in the reference partition causes a change in the bias status (e.g.,
NCinc, NCdec) of a CVI. For example, NCinc bias in the RI can be changed to
NCdec bias by skewing the distribution of clusters in the ground truth
partition. It is important for users to be aware of this new type of biased
behaviour, since it may affect the interpretations of CVI results. The
objective of this article is to study the empirical and theoretical
implications of GT bias. To the best of our knowledge, this is the first
extensive study of such a property for external cluster validity indices.


title: Adding Context to Concept Trees

abstract:
  A Concept Tree is a structure for storing knowledge where the trees are
stored in a database called a Concept Base. It sits between the highly
distributed neural architectures and the distributed information systems, with
the intention of bringing brain-like and computer systems closer together.
Concept Trees can grow from the semi-structured sources when consistent
sequences of concepts are presented. Each tree ideally represents a single
cohesive concept and the trees can link with each other for navigation and
semantic purposes. The trees are therefore also a type of semantic network and
would benefit from having a consistent level of context for each node. A
consistent build process is managed through a 'counting rule' and some other
rules that can normalise the database structure. This restricted structure can
then be complimented and enriched by the more dynamic context. It is also
suggested to use the linking structure of the licas system [15] as a basis for
the context links, where the mathematical model is extended further to define
this. A number of tests have demonstrated the soundness of the architecture.
Building the trees from text documents shows that the tree structure could be
inherent in natural language. Then, two types of query language are described.
Both of these can perform consistent query processes to return knowledge to the
user and even enhance the query with new knowledge. This is supported even
further with direct comparisons to a cognitive model, also being developed by
the author.


title: Identifiability and testability in GRT with Individual Differences

abstract:
  Silbert and Thomas (2013) showed that failures of decisional separability are
not, in general, identifiable in fully parameterized $2 \times 2$ Gaussian GRT
models. A recent extension of $2 \times 2$ GRT models (GRTwIND) was developed
to solve this problem and a conceptually similar problem with the simultaneous
identifiability of means and marginal variances in GRT models. Central to the
ability of GRTwIND to solve these problems is the assumption of universal
perception, which consists of shared perceptual distributions modified by
attentional and global scaling parameters (Soto et al., 2015). If universal
perception is valid, GRTwIND solves both issues. In this paper, we show that
GRTwIND with universal perception and subject-specific failures of decisional
separability is mathematically, and thereby empirically, equivalent to a model
with decisional separability and failure of universal perception. We then
provide a formal proof of the fact that means and marginal variances are not,
in general, simultaneously identifiable in $2 \times 2$ GRT models, including
GRTwIND. These results can be taken to delineate precisely what the assumption
of universal perception must consist of. Based on these results and related
recent mathematical developments in the GRT framework, we propose that, in
addition to requiring a fixed subset of parameters to determine the location
and scale of any given GRT model, some subset of parameters must be set in GRT
models to fix the orthogonality of the modeled perceptual dimensions, a central
conceptual underpinning of the GRT framework. We conclude with a discussion of
perceptual primacy and its relationship to universal perception.


title:
A note on the independent domination number versus the domination number
  in bipartite graphs

abstract:
  Let $\gamma(G)$ and $i(G)$ be the domination number and the independent
domination number of $G$, respectively. Rad and Volkmann posted a conjecture
that $i(G)/ \gamma(G) \leq \Delta(G)/2$ for any graph $G$, where $\Delta(G)$ is
its maximum degree (See \cite{5}: N.J. Rad, L. Volkmann, A note on the
independent domination number in graphs. Discrete Appl. Math. 161(2013)
3087--3089). In this work, we verify the conjecture for bipartite graphs.
Several graph classes attaining the extremal bound and graphs containing odd
cycles with the ratio larger than $\Delta(G)/2$ are provided as well.


title:
Stochastic transport in the presence of spatial disorder:
  fluctuation-induced corrections to homogenization

abstract:
  Motivated by uncertainty quantification in natural transport systems, we
investigate an individual-based transport process involving particles
undergoing a random walk along a line of point sinks whose strengths are
themselves independent random variables. We assume particles are removed from
the system via first-order kinetics. We analyse the system using a hierarchy of
approaches when the sinks are sparsely distributed, including a stochastic
homogenization approximation that yields explicit predictions for the extrinsic
disorder in the stationary state due to sink strength fluctuations. The
extrinsic noise induces long-range spatial correlations in the particle
concentration, unlike fluctuations due to the intrinsic noise alone.
Additionally, the mean concentration profile, averaged over both intrinsic and
extrinsic noise, is elevated compared with the corresponding profile from a
uniform sink distribution, showing that the classical homogenization
approximation can be a biased estimator of the true mean.


title:
Criteria for the Existence of Principal Eigenvalues of Time Periodic
  Cooperative Linear Systems with Nonlocal Dispersal

abstract:
  The current paper {establishes} criteria for the existence of principal
eigenvalues of time periodic cooperative linear nonlocal dispersal systems with
Direchlet type, Neumann type or periodic type boundary conditions. It is shown
that such a nonlocal dispersal system has a principal eigenvalue in the
following cases: the nonlocal dispersal distance is sufficiently small; the
spatial inhomogeneity satisfies a so called vanishing condition; or the spatial
inhomogeneity is nearly globally homogeneous. Moreover, it is shown that the
principal eigenvalue of a time periodic cooperative linear nonlocal dispersal
system (if it exists) is algebraically simple. A linear nonlocal dispersal
system may not have a principal eigenvalue. The results established in the
current paper extend those in literature for time independent or periodic
nonlocal dispersal equations to time periodic cooperative nonlocal dispersal
systems and {will} serve as {a} basic tool for the study of cooperative
nonlinear systems with nonlocal dispersal.


title:
Some Remarks on the Topology of Hyperbolic Actions of $\mathbb{R}^n$ on
  $n$-manifolds

abstract:
  This paper contains some more results on the topology of a nondegenerate
action of $\mathbb{R}^n$ on a compact connected $n$-manifold $M$ when the
action is totally hyperbolic (i.e. its toric degree is zero). We study the
$\mathbb{R}$-action generated by a fixed vector of $\mathbb{R}^n$, that
provides some results on the number of hyperbolic domains and the number of
fixed points of the action. We study with more details the case of the
2-sphere, in particular we investigate some combinatorial properties of the
associated 4-valent graph embedded in $S^2$. We also construct hyperbolic
actions in dimension 3, on the sphere $S^3$ and on the projective space
$\mathbb{RP}^3$.


title:
The end states of long-period comets and the origin of Halley-type
  comets

abstract:
  We analyze a sample of 73 old long-period comets (LPCs) (orbital periods $200
< P < 1000$ yr) with perihelion distances $q < 2.5$ au, discovered in the
period 1850-2014. We cloned the observed comets and also added fictitious LPCs
with perihelia in the Jupiter's zone. We consider both a purely dynamical
evolution and a physico-dynamical one with different physical lifetimes. We can
fit the computed energy distribution of comets with $q < 1.3$ au to the
observed one only within the energy range $0.01 < x < 0.04$ au$^{-1}$ (or
periods $125 < P < 1000$ yr), where the "energy" is taken as the inverse of the
semimajor axis $a$, namely $x \equiv 1/a$. The best results are obtained for
physical lifetimes of about 200-300 revolutions (for a comet with a standard $q
= 1$ au). We find that neither a purely dynamical evolution, nor a
physico-dynamical one can reproduce the long tail of larger binding energies
($x \gsim 0.04$ au$^{-1}$) that correspond to most Halley-type comets (HTCs)
and Jupiter-family comets. We conclude that most HTCs are not the end states of
the evolution of LPCs, but come from a different source, a flattened one that
we identify with the Centaurs that are scattered to the inner planetary region
from the trans-Neptunian belt. These results also show that the boundary
between LPCs and HTCs should be located at an energy $x \sim 0.04$ au$^{-1}$
($P \sim 125$ yr), rather than the conventional classical boundary at $P = 200$
yr.


title: Compare triangular bases of acyclic quantum cluster algebras

abstract:
  Given a quantum cluster algebra, we show that its triangular bases defined by
Berenstein and Zelevinsky and those defined by the author are the same for the
seeds associated with acyclic quivers. This result implies that the
Berenstein-Zelevinsky's basis contains all the quantum cluster monomials.
  We also give an easy proof that the two bases are the same for the seeds
associated with bipartite skew-symmetrizable matrices.


title: Interaction of axions with relativistic spinning particles

abstract:
  We consider a covariant phenomenological model, which describes an
interaction between a pseudoscalar (axion) field and massive spinning
particles. The model extends the Bagrmann-Michel-Telegdy approach in
application to the axion electrodynamics. We present some exact solutions and
discuss them in the context of experimental tests of the model and axion
detection.


title: On the Commutative Algebra of Categories

abstract:
  We discuss what it means for a symmetric monoidal category to be a module
over a commutative semiring category. Each of the categories of (1) cartesian
monoidal categories, (2) semiadditive categories, and (3) connective spectra
can be recovered in this way as categories of modules over a commutative
semiring category (or $\infty$-category in the last case). This language
provides a simultaneous generalization of the formalism of algebraic theories
(operads, PROPs, Lawvere theories) and stable homotopy theory, with essentially
a variant of algebraic K-theory bridging between the two.


title:
Vector Dark-Antidark Solitary Waves in Multi-Component Bose-Einstein
  condensates

abstract:
  Multi-component Bose-Einstein condensates exhibit an intriguing variety of
nonlinear structures. In recent theoretical work, the notion of magnetic
solitons has been introduced. Here we generalize this concept to vector
dark-antidark solitary waves in multi-component Bose-Einstein condensates. We
first provide concrete experimental evidence for such states in an atomic BEC
and subsequently illustrate the broader concept of these states, which are
based on the interplay between miscibility and inter-component repulsion. Armed
with this more general conceptual framework, we expand the notion of such
states to higher dimensions presenting the possibility of both vortex-antidark
states and ring-antidark-ring (dark soliton) states. We perform numerical
continuation studies, investigate the existence of these states and examine
their stability using the method of Bogolyubov-de Gennes analysis.
Dark-antidark and vortex-antidark states are found to be stable for broad
parametric regimes. In the case of ring dark solitons, where the
single-component ring state is known to be unstable, the vector entity appears
to bear a progressively more and more stabilizing role as the inter-component
coupling is increased.


title:
Explicit correlation amplifiers for finding outlier correlations in
  deterministic subquadratic time

abstract:
  We derandomize G. Valiant's [J. ACM 62 (2015) Art. 13] subquadratic-time
algorithm for finding outlier correlations in binary data. Our derandomized
algorithm gives deterministic subquadratic scaling essentially for the same
parameter range as Valiant's randomized algorithm, but the precise constants we
save over quadratic scaling are more modest. Our main technical tool for
derandomization is an explicit family of correlation amplifiers built via a
family of zigzag-product expanders in Reingold, Vadhan, and Wigderson [Ann. of
Math. 155 (2002) 157--187]. We say that a function
$f:\{-1,1\}^d\rightarrow\{-1,1\}^D$ is a correlation amplifier with threshold
$0\leq\tau\leq 1$, error $\gamma\geq 1$, and strength $p$ an even positive
integer if for all pairs of vectors $x,y\in\{-1,1\}^d$ it holds that (i)
$|\langle x,y\rangle|<\tau d$ implies $|\langle
f(x),f(y)\rangle|\leq(\tau\gamma)^pD$; and (ii) $|\langle x,y\rangle|\geq\tau
d$ implies $\bigl(\frac{\langle x,y\rangle}{\gamma d}\bigr)^pD
  \leq\langle f(x),f(y)\rangle\leq
  \bigl(\frac{\gamma\langle x,y\rangle}{d}\bigr)^pD$.


title: Research on Wikipedia Vandalism: a brief literature review

abstract:
  Research on vandalism in Wikipedia has been of interest for the last decade.
This paper performs a literature review on the subject, with the goal of
identifying the main research topics and approaches, methods and techniques
used. 67 papers have been reviewed. Main topic is the detection of vandalism,
although there is a increasing interest about content quality. The most
commonly used technique is machine learning, based on feature analysis. It
draws attention to the lack of research on information behavior of vandals.


title: CP Symmetry and Lepton Mixing from a Scan of Finite Discrete Groups

abstract:
  Including the generalized CP symmetry, we have performed a comprehensive scan
of leptonic mixing patterns which can be obtained from finite discrete groups
with order less than 2000. Both the semidirect approach and its variant are
considered. The lepton mixing matrices which can admit a good agreement with
experimental data can be organized into eight different categories up to
possible row and column permutations. These viable mixing patterns can be
completely obtained from the discrete flavor groups $\Delta(6n^2)$,
$D^{(1)}_{9n,3n}$, $A_5$ and $\Sigma(168)$ combined with CP symmetry. We
perform a detailed analytical and numerical analysis for each possible mixing
pattern. The resulting predictions for lepton mixing parameter, neutrinoless
double decay and flavored leptogenesis are studied.


title:
Data-driven HR - R\'esum\'e Analysis Based on Natural Language
  Processing and Machine Learning

abstract:
  Recruiters usually spend less than a minute looking at each r\'esum\'e when
deciding whether it's worth continuing the recruitment process with the
candidate. Recruiters focus on keywords, and it's almost impossible to
guarantee a fair process of candidate selection. The main scope of this paper
is to tackle this issue by introducing a data-driven approach that shows how to
process r\'esum\'es automatically and give recruiters more time to only examine
promising candidates. Furthermore, we show how to leverage Machine Learning and
Natural Language Processing in order to extract all required information from
the r\'esum\'es. Once the information is extracted, a ranking score is
calculated. The score describes how well the candidates fit based on their
education, work experience and skills. Later this paper illustrates a prototype
application that shows how this novel approach can increase the productivity of
recruiters. The application enables them to filter and rank candidates based on
predefined job descriptions. Guided by the ranking, recruiters can get deeper
insights from candidate profiles and validate why and how the application
ranked them. This application shows how to improve the hiring process by giving
an unbiased hiring decision support.


title:
Time dependence of Fe/O ratio within a 3D Solar Energetic Particle
  propagation model including drift

abstract:
  Context. The intensity profiles of iron and oxygen in Solar Energetic
Particle (SEP) events often display differences that result in a decreasing
Fe/O ratio over time. The physical mechanisms behind this behaviour are not
fully understood, but these observational signatures provide important tests of
physical modelling efforts. Aims. In this paper we study the propagation of
iron and oxygen SEP ions using a 3D model of propagation which includes the
effect of guiding centre drift in a Parker spiral magnetic field. We derive
time intensity profiles for a variety of observer locations and study the
temporal evolution of the Fe/O ratio. Methods. We use a 3D full orbit test
particle model which includes scattering. The configuration of the
interplanetary magnetic field is a unipolar Parker spiral. Particles are
released instantaneously from a compact region at 2 solar radii and allowed to
propagate in 3D. Results. Both Fe and O experience significant transport across
the magnetic field due to gradient and curvature drifts. We find that Fe ions
drift more than O ions due to their larger mass-to-charge ratio, so that an
observer that is not magnetically well connected to the source region will
observe Fe arriving before O, for particles within the same range in energy per
nucleon. As a result, for the majority of observer locations, the Fe/O ratio
displays a decrease in time. Conclusions. We conclude that propagation effects
associated with drifts produce a decay over time of the Fe/O ratio,
qualitatively reproducing that observed in SEP event profiles.


title:
Controlling the intensity of light in large areas at the interfaces of a
  scattering medium

abstract:
  The recent advent of wave-shaping methods has demonstrated the focusing of
light through and inside even the most strongly scattering materials. Typically
in wavefront shaping, light is focused in an area with the size of one speckle
spot. It has been shown that the intensity is not only increased in the target
speckle spot, but also in an area outside the optimized speckle spot.
Consequently, the total transmission is enhanced, even though only the
intensity in a single speckle spot is controlled. Here, we experimentally study
how the intensity enhancement on both interfaces of a scattering medium depends
on the optimization area on the transmission side. We observe that as the
optimization radius increases, the enhancement of the total transmitted
intensity increases. We find a concomitant decrease of the total reflected
intensity, which implies an energy redistribution between transmission and
reflection channels. In addition, we find a qualitative evidence of a
long-range reflection-transmission correlation. Our result is useful for
efficient light harvesting in solar cells, multi-channel quantum secure
communications, imaging, and complex beam delivery through a scattering medium.


title: High-resolution LIDAR-based Depth Mapping using Bilateral Filter

abstract:
  High resolution depth-maps, obtained by upsampling sparse range data from a
3D-LIDAR, find applications in many fields ranging from sensory perception to
semantic segmentation and object detection. Upsampling is often based on
combining data from a monocular camera to compensate the low-resolution of a
LIDAR. This paper, on the other hand, introduces a novel framework to obtain
dense depth-map solely from a single LIDAR point cloud; which is a research
direction that has been barely explored. The formulation behind the proposed
depth-mapping process relies on local spatial interpolation, using
sliding-window (mask) technique, and on the Bilateral Filter (BF) where the
variable of interest, the distance from the sensor, is considered in the
interpolation problem. In particular, the BF is conveniently modified to
perform depth-map upsampling such that the edges (foreground-background
discontinuities) are better preserved by means of a proposed method which
influences the range-based weighting term. Other methods for spatial upsampling
are discussed, evaluated and compared in terms of different error measures.
This paper also researches the role of the mask's size in the performance of
the implemented methods. Quantitative and qualitative results from experiments
on the KITTI Database, using LIDAR point clouds only, show very satisfactory
performance of the approach introduced in this work.


title:
Guaranteed Non-convex Optimization: Submodular Maximization over
  Continuous Domains

abstract:
  Submodular continuous functions are a category of (generally)
non-convex/non-concave functions with a wide spectrum of applications. We
characterize these functions and demonstrate that they can be maximized
efficiently with approximation guarantees. Specifically, i) We introduce the
weak DR property that gives a unified characterization of submodularity for all
set, integer-lattice and continuous functions; ii) for maximizing monotone
DR-submodular continuous functions under general down-closed convex
constraints, we propose a Frank-Wolfe variant with $(1-1/e)$ approximation
guarantee, and sub-linear convergence rate; iii) for maximizing general
non-monotone submodular continuous functions subject to box constraints, we
propose a DoubleGreedy algorithm with $1/3$ approximation guarantee. Submodular
continuous functions naturally find applications in various real-world
settings, including influence and revenue maximization with continuous
assignments, sensor energy management, multi-resolution data summarization,
facility location, etc. Experimental results show that the proposed algorithms
efficiently generate superior solutions compared to baseline algorithms.


title:
The minimum vertex degree for an almost-spanning tight cycle in a
  $3$-uniform hypergraph

abstract:
  We prove that any $3$-uniform hypergraph whose minimum vertex degree is at
least $\left(\frac{5}{9} + o(1) \right)\binom{n}{2}$ admits an almost-spanning
tight cycle, that is, a tight cycle leaving $o(n)$ vertices uncovered. The
bound on the vertex degree is asymptotically best possible. Our proof uses the
hypergraph regularity method, and in particular a recent version of the
hypergraph regularity lemma proved by Allen, B\"ottcher, Cooley and Mycroft.


title: Algebraic Cycles Representing Cohomology Operations

abstract:
  In this paper we show that certain universal homology classes which are
fundamental in topology are algebraic. To be specific, the products of
Eilenberg-MacLane spaces ${\cal K}_{2q} \equiv K({\Bbb Z},2) \times K({\Bbb Z},
4) \times ... \times K({\Bbb Z}, 2q)$ have models which are limits of complex
projective varieties. Precisely, we have ${\cal K}_{2q} =
\lim_{d\to\infty}{\cal C}_d^q({\Bbb P}^n)$ where ${\cal C}_d^q({\Bbb P}^n)$
denotes the Chow variety of effective cycles of codimension $q$ and degree $d$
on ${\Bbb P}^n$. It is natural to ask which elements in the homology of ${\cal
K}_{2q}$ are represented by algebraic cycles in these approximations. In this
paper we find such representations for the even dimensional classes known as
Steenrod squares (as well as their Pontrjagin and join products). These classes
are dual to the cohomology classes which correspond to the basic cohomology
operations also known as the Steenrod squares.


title:
Density of States under non-local interactions II. Simplified
  polynomially screened interactions

abstract:
  Following [5], we analyze regularity properties of single-site probability
distributions of the random potential and of the Integrated Density of States
(IDS) in the Anderson models with infinite-range interactions. In the present
work, we study in detail a class of polynomially decaying interaction
potentials of rather artificial (piecewise-constant) form, and give a complete
proof of infinite smoothness of the IDS in an arbitrarily large finite domain
subject to the fluctuations of the entire, infinite random environment. A
variant of this result, based as in [5] on the harmonic analysis of probability
measures, results in a proof of spectral and dynamical Anderson localization in
the considered models.


title: Data Privacy and Specimen Pooling: Using an old tool for New Challenges

abstract:
  Background: In the context of ongoing debate over data confidentiality versus
shared use of research data, as raised following the new EU General Data
Protection Regulation, we seek to find alternate techniques that can balance
these two issues. In particular, we demonstrate that an existing epidemiologic
tool, specimen pooling, can be adapted as a privacy-preserving method to enable
data analysis while maintaining data confidentiality. Specimen pooling is a
cost-effective tool in studying the effect of an expensive-to-measure exposure
on a disease outcome, for both unmatched and matched case-control designs. We
propose the technique in a new context to analyze confidential data and
demonstrate that it can be successfully used to estimate OR of covariates based
on aggregate data when individual patient data cannot be shared.
  Methods: We demonstrate the application of specimen pooling based on
aggregate covariate level and show that aggregated covariate levels can be used
in a conditional logistic regression model to estimate individual-level odds
ratio parameters of interest. We then show how to adapt the technique as a
privacy-preserving method to analyze data from a matched case-control design. A
similar approach can be applied for an unmatched design and unconditional
logistic regression.
  Results: The parameter estimates from the standard conditional logistic
regression are compared to those based on aggregated data. The parameter
estimates are similar and have similar standard errors and confidence interval
coverage.
  Conclusions: Pooling can be used effectively to analyze confidential data
arising from distributed data networks and will be extremely useful in
pharmacoepidemiology.


title: On derivations of subalgebras of real semisimple Lie algebras

abstract:
  Let $\mathfrak{g}$ be a real semisimple Lie algebra with Iwasawa
decomposition $\mathfrak{k} \oplus \mathfrak{a} \oplus \mathfrak{n}$. We show
that, except for some explicit exceptional cases, every derivation of the
nilpotent subalgebra $\mathfrak{n}$ that preserves its restricted root space
decomposition is of the form $\text{ad}( W)$, where $W \in \mathfrak{m}\oplus .


title:
Design of Synchronous Section-Carry Based Carry Lookahead Adders with
  Improved Figure of Merit

abstract:
  The section-carry based carry lookahead adder (SCBCLA) architecture was
proposed as an efficient alternative to the conventional carry lookahead adder
(CCLA) architecture for the physical implementation of computer arithmetic. In
previous related works, self-timed SCBCLA architectures and synchronous SCBCLA
architectures were realized using standard cells and FPGAs. In this work, we
deal with improved realizations of synchronous SCBCLA architectures designed in
a semi-custom fashion using standard cells. The improvement is quantified in
terms of a figure of merit (FOM), where the FOM is defined as the inverse
product of power, delay and area. Since power, delay and area of digital
designs are desirable to be minimized, the FOM is desirable to be maximized.
Starting from an efficient conventional carry lookahead generator, we show how
an optimized section-carry based carry lookahead generator is realized. In
comparison with our recent work dealing with standard cells based
implementation of SCBCLAs to perform 32-bit addition of two binary operands, we
show in this work that with improved section-carry based carry lookahead
generators, the resulting SCBCLAs exhibit significant improvements in FOM.
Compared to the earlier optimized hybrid SCBCLA, the proposed optimized hybrid
SCBCLA improves the FOM by 88.3%. Even the optimized hybrid CCLA features
improvement in FOM by 77.3% over the earlier optimized hybrid CCLA. However,
the proposed optimized hybrid SCBCLA is still the winner and has a better FOM
than the currently optimized hybrid CCLA by 15.3%. All the CCLAs and SCBCLAs
are implemented to realize 32-bit dual-operand binary addition using a 32/28nm
CMOS process.


title: Homoclinic orbits in the Euler problem of two fixed centers

abstract:
  We give a complete description of the shapes and the behavior of all
homoclinic orbits in the Euler problem of two fixed centers.


title:
Alternative paths to realize Majorana Fermions in
  Superconductor-Ferromagnet Heterostructures

abstract:
  A fundamental obstacle for achieving quantum computation is local
decoherence. One way to circumvent this problem rests on the concepts of
topological quantum computation using non-local information storage, for
example on pairs of Majorana fermions (MFs). The arguably most promising way to
generate MFs relies at present on spin-triplet p-wave states of superconductors
(SC), which are not abundant in nature, unfortunately. Thus, proposals for
their engineering in devices, usually via proximity effect from a conventional
SC into materials with strong spinorbit coupling (SOC), are intensively
investigated nowadays. Here we take an alternative path, exploiting the
different connections between fields based on a quartet coupling rule for
fields introduced by one of us, we demonstrate that, for instance, coexisting
Zeeman field with a charge current would provide the conditions to induce
p-wave pairing in the presence of singlet superconductivity. This opens new
avenues for the engineering of robust MFs in various, not necessarily
(quasi-)one-dimensional, superconductor-ferromagnet heterostructures, including
such motivated by recent pioneering experiments that report MFs, in particular,
without the need of any exotic materials with special structures of intrinsic
SOC.


title: Metastable Localization of Diseases in Complex Networks

abstract:
  We describe the phenomenon of localization in the epidemic SIS model on
highly heterogeneous networks in which strongly connected nodes (hubs) play the
role of centers of localization. We find that in this model the localized
states below the epidemic threshold are metastable. The longevity and scale of
the metastable outbreaks do not show a sharp localization transition, instead
there is a smooth crossover from localized to delocalized states as we approach
the epidemic threshold from below. Analyzing these long-lasting local outbreaks
for a random regular graph with a hub, we show how this localization can be
detected from the shape of the distribution of the number of infective nodes.


title: Fermion zero modes in a $Z_2$ vortex background

abstract:
  In this paper we study the zero energy solutions of the Dirac equation in the
background of a $Z_2$ vortex of a non-Abelian gauge model with three charged
scalar fields. We determine the number of the fermionic zero modes giving their
explicit form for two specific Ansatze.


title: The complexity of simulating local measurements on quantum systems

abstract:
  An important task in quantum physics is the estimation of local quantities
for ground states of local Hamiltonians. Recently, [Ambainis, CCC 2014] defined
the complexity class P^QMA[log], and motivated its study by showing that the
physical task of estimating the expectation value of a local observable against
the ground state of a local Hamiltonian is P^QMA[log]-complete. In this paper,
we continue the study of P^QMA[log], obtaining the following lower and upper
bounds.
  Lower bounds (hardness results): (1) The P^QMA[log]-completeness result of
[Ambainis, CCC 2014] requires O(log n)-local observables and Hamiltonians. We
show that simulating even a single qubit measurement on ground states of
5-local Hamiltonians is P^QMA[log]-complete, resolving an open question of
Ambainis. (2) We formalize the complexity theoretic study of estimating
two-point correlation functions against ground states, and show that this task
is similarly P^QMA[log]-complete. (3) We identify a flaw in [Ambainis, CCC
2014] regarding a P^UQMA[log]-hardness proof for estimating spectral gaps of
local Hamiltonians. By introducing a "query validation" technique, we build on
[Ambainis, CCC 2014] to obtain P^UQMA[log]-hardness for estimating spectral
gaps under polynomial-time Turing reductions.
  Upper bounds (containment in complexity classes): P^QMA[log] is thought of as
"slightly harder" than QMA. We justify this formally by exploiting the
hierarchical voting technique of [Beigel, Hemachandra, Wechsung, SCT 1989] to
show P^QMA[log] is in PP. This improves the containment QMA is in PP [Kitaev,
Watrous, STOC 2000].
  This work contributes a rigorous treatment of the subtlety involved in
studying oracle classes in which the oracle solves a promise problem. This is
particularly relevant for quantum complexity theory, where most natural classes
such as BQP and QMA are defined as promise classes.


title:
Anomalous transport model study of chiral magnetic effects in heavy ion
  collisions

abstract:
  Using an anomalous transport model for massless quarks and antiquarks, we
study the effect of a magnetic field on the elliptic flows of quarks and
antiquarks in relativistic heavy ion collisions. With initial conditions from a
blast wave model and assuming that the strong magnetic field produced in
non-central heavy ion collisions can last for a sufficiently long time, we
obtain an appreciable electric quadrupole moment in the transverse plane of a
heavy ion collision. The electric quadrupole moment subsequently leads to a
splitting between the elliptic flows of quarks and antiquarks. The slope of the
charge asymmetry dependence of the elliptic flow difference between positively
and negatively charged particles is positive, which is expected from the chiral
magnetic wave formed in the produced QGP and observed in experiments at the BNL
Relativistic Heavy Ion Collider, only if the Lorentz force acting on the
charged particles is neglected and the quark-antiquark scattering is assumed to
be dominated by the chirality changing channel.


title: On ordered Ramsey numbers of bounded-degree graphs

abstract:
  An ordered graph is a pair $\mathcal{G}=(G,\prec)$ where $G$ is a graph and
$\prec$ is a total ordering of its vertices. The ordered Ramsey number
$\overline{R}(\mathcal{G})$ is the minimum number $N$ such that every
$2$-coloring of the edges of the ordered complete graph on $N$ vertices
contains a monochromatic copy of $\mathcal{G}$.
  We show that for every integer $d \geq 3$, almost every $d$-regular graph $G$
satisfies $\overline{R}(\mathcal{G}) \geq
\frac{n^{3/2-1/d}}{4\log{n}\log{\log{n}}}$ for every ordering $\mathcal{G}$ of
$G$. In particular, there are 3-regular graphs $G$ on $n$ vertices for which
the numbers $\overline{R}(\mathcal{G})$ are superlinear in $n$, regardless of
the ordering $\mathcal{G}$ of $G$. This solves a problem of Conlon, Fox, Lee,
and Sudakov.
  On the other hand, we prove that every graph $G$ on $n$ vertices with maximum
degree 2 admits an ordering $\mathcal{G}$ of $G$ such that
$\overline{R}(\mathcal{G})$ is linear in $n$.
  We also show that almost every ordered matching $\mathcal{M}$ with $n$
vertices and with interval chromatic number two satisfies
$\overline{R}(\mathcal{M}) \geq cn^2/\log^2{n}$ for some absolute constant $c$.


title:
Ultrafast laser pulse heating of metallic photocathodes and its
  contribution to intrinsic emittance

abstract:
  The heating of the electronic distribution of a copper photocathode due to an
intense drive laser pulse is calculated under the two-temperature model using
fluences and pulse lengths typical in RF photoinjector operation. Using the
finite temperature-extended relations for the photocathode intrinsic emittance
and quantum efficiency, the time-dependent emittance growth due to the same
photoemission laser pulse is calculated. This laser heating is seen to limit
the intrinsic emittance achievable for photoinjectors using short laser pulses
and low quantum efficiency metal photocathodes. A pump-probe photocathode
experiment in a standard 1.6 cell S-band gun is proposed, in which simulations
show the time dependent thermal emittance modulation within the bunch from
laser heating can persist for meters downstream and, in principle, be measured
using a slice emittance diagnostic.


title:
A cubic nonconventional ergodic average with multiplicative or Mangoldt
  weights

abstract:
  We show that the cubic nonconventional ergodic averages of any order with a
bounded multiplicative function weight converge almost surely to zero provided
that the multiplicative function satisfies a strong Daboussi-Delange condition.
We further obtain that the Ces\`{a}ro mean of the self-correlations and some
moving average of the self-correlations of such multiplicative functions
converge to zero. Our proof gives, for any $N \geq 2$,
$$\frac1{N}\sum_{m=1}^{N}\Big|\frac1{N}\sum_{n=1}^{N} \bnu(n) \bnu(n+m)\Big|
\leq \frac{C}{\log(N)^{\epsilon}},$$ and
$$\frac1{N^2}\sum_{n,p=1}^{N}\Big|\frac1{N}\sum_{m=1}^{N} \bnu(m)
\bnu(n+m)\bnu(m+p)\bnu(n+m+p)\Big| \leq \frac{C}{\log(N)^{\varepsilon}},$$
where $C,\varepsilon$ are some positive constants and $\bnu$ is a bounded
multiplicative function satisfying a Daboussi-Delange condition with
logarithmic speed. We further establish that the cubic nonconventional ergodic
averages of any order with Mangoldt weight converge almost surely provided that
all the systems are nilsystems.


title:
Variational formulation and numerical analysis of linear elliptic
  equations in nondivergence form with Cordes coefficients

abstract:
  This paper studies formulations of second-order elliptic partial differential
equations in nondivergence form on convex domains as equivalent variational
problems. The first formulation is that of Smears \& S\"uli [SIAM J.\ Numer.\
Anal.\ 51(2013), pp.\ 2088--2106.], and the second one is a new symmetric
formulation based on a least-squares functional. These formulations enable the
use of standard finite element techniques for variational problems in subspaces
of $H^2$ as well as mixed finite element methods from the context of fluid
computations. Besides the immediate quasi-optimal a~priori error bounds, the
variational setting allows for a~posteriori error control with explicit
constants and adaptive mesh-refinement. The convergence of an adaptive
algorithm is proved. Numerical results on uniform and adaptive meshes are
included.


title:
Enhancement of Supersymmetry via Renormalization Group Flow and the
  Superconformal Index

abstract:
  We find a four-dimensional N=1 gauge theory which flows to the minimal
interacting N=2 superconformal field theory, the Argyres-Douglas theory, in the
infrared up to the extra free chiral multiplets. The gauge theory is obtained
from a certain N=1 preserving deformation of the N=2 SU(2) gauge theory with
four fundamental hypermultiplets. From this description, we compute the full
superconformal index and find agreements with the known results in special
limits.


title: Equi-depth Histogram Construction for Big Data with Quality Guarantees

abstract:
  The amount of data generated and stored in cloud systems has been increasing
exponentially. The examples of data include user generated data, machine
generated data as well as data crawled from the Internet. There have been
several frameworks with proven efficiency to store and process the petabyte
scale data such as Apache Hadoop, HDFS and several NoSQL frameworks. These
systems have been widely used in industry and thus are subject to several
research. The proposed data processing techniques should be compatible with the
above frameworks in order to be practical. One of the key data operations is
deriving equi-depth histograms as they are crucial in understanding the
statistical properties of the underlying data with many applications including
query optimization. In this paper, we focus on approximate equi-depth histogram
construction for big data and propose a novel merge based histogram
construction method with a histogram processing framework which constructs an
equi-depth histogram for a given time interval. The proposed method constructs
approximate equi-depth histograms by merging exact equi-depth histograms of
partitioned data by guaranteeing a maximum error bound on the number of items
in a bucket (bucket size) as well as any range on the histogram.


title:
Common Codebook Millimeter Wave Beam Design: Designing Beams for Both
  Sounding and Communication with Uniform Planar Arrays

abstract:
  Fifth generation (5G) wireless networks are expected to utilize wide
bandwidths available at millimeter wave (mmWave) frequencies for enhancing
system throughput. However, the unfavorable channel conditions of mmWave links,
e.g., higher path loss and attenuation due to atmospheric gases or water vapor,
hinder reliable communications. To compensate for these severe losses, it is
essential to have a multitude of antennas to generate sharp and strong beams
for directional transmission. In this paper, we consider mmWave systems using
uniform planar array (UPA) antennas, which effectively place more antennas on a
two-dimensional grid. A hybrid beamforming setup is also considered to generate
beams by combining a multitude of antennas using only a few radio frequency
chains. We focus on designing a set of transmit beamformers generating beams
adapted to the directional characteristics of mmWave links assuming a UPA and
hybrid beamforming. We first define ideal beam patterns for UPA structures.
Each beamformer is constructed to minimize the mean squared error from the
corresponding ideal beam pattern. Simulation results verify that the proposed
codebooks enhance beamforming reliability and data rate in mmWave systems.


title: Quantum fate of timelike naked singularity with scalar hair

abstract:
  We study the quantum fate of a naked curvature singularity sourced by a
scalar field via several methods and compare the results obtained. The first
method relies on relativistic quantum mechanics on a fixed background employing
the Klein--Gordon and the Dirac equations for a static spacetime. We show that
both the Klein--Gordon and the Dirac particles feel this singularity therefore
this method does not provide its resolution. For comparison, we subsequently
employ methods for quantizing the geometry itself. We selected the canonical
quantization via conditional symmetries and as a last approach we use a maximal
acceleration derivation in the covariant loop quantum gravity. In both of these
approaches the singularity is resolved at the quantum level. We discuss these
conflicting results bearing in mind that quantum particles probe classical
geometry in the first approach while the last two methods quantize the geometry
itself.


title: On the null origin of the ambitwistor string

abstract:
  In this paper we present the null string origin of the ambitwistor string.
Classically, the null string is the tensionless limit of string theory, and so
too is the Ambitwistor string. Both have as constraint algebra the Galilean
Conformal Algebra in two dimensions. But something interesting happens in the
quantum theory since there is an ambiguity in quantizing the null string. We
show that, given a particular choice of quantization scheme and a particular
gauge, the null string coincides with the ambitwistor string both classically
and quantum mechanically. We also show that the same holds for the spinning
versions of the null string and Ambitwistor string. With these results we
clarify the relationship between the Ambitwistor string, the null string, the
usual string and the Hohm-Siegel-Zwiebach theory.


title: Non-classical photon correlation in a two-dimensional photonic lattice

abstract:
  Quantum interference and quantum correlation, as two main features of quantum
optics, play an essential role in quantum information applications, such as
multi-particle quantum walk and boson sampling. While many experimental
demonstrations have been done in one-dimensional waveguide arrays, it remains
unexplored in higher dimensions due to tight requirement of manipulating and
detecting photons in large-scale. Here, we experimentally observe non-classical
correlation of two identical photons in a fully coupled two-dimensional
structure, i.e. photonic lattice manufactured by three-dimensional femtosecond
laser writing. Photon interference consists of 36 Hong-Ou-Mandel interference
and 9 bunching. The overlap between measured and simulated distribution is up
to $0.890\pm0.001$. Clear photon correlation is observed in the two-dimensional
photonic lattice. Combining with controllably engineered disorder, our results
open new perspectives towards large-scale implementation of quantum simulation
on integrated photonic chips.


title:
A Lightcone Embedding of the Twin Building of a Hyperbolic Kac-Moody
  Group

abstract:
  Let A be a symmetrizable hyperbolic generalized Cartan matrix with Kac-Moody
algebra g = g(A) and (adjoint) Kac-Moody group G = G(A)=$\langle\exp(ad(t
e_i)), \exp(ad(t f_i)) \,|\, t\in C\rangle$ where $e_i$ and $f_i$ are the
simple root vectors. Let $(B^+, B^-, N)$ be the twin BN-pair naturally
associated to G and let $(\mathcal B^+,\mathcal B^-)$ be the corresponding twin
building with Weyl group W and natural G-action, which respects the usual
W-valued distance and codistance functions. This work connects the twin
building of G and the Kac-Moody algebra g in a new geometrical way. The
Cartan-Chevalley involution, $\omega$, of g has fixed point real subalgebra, k,
the 'compact' (unitary) real form of g, and k contains the compact Cartan t = k
$\cap$ h. We show that a real bilinear form $(\cdot,\cdot)$ is Lorentzian with
signatures $(1, \infty)$ on k, and $(1, n -1)$ on t. We define $\{x\in {\rm k}
\,|\, (x, x) \leq 0\}$ to be the lightcone of k, and similarly for t. Let K be
the compact (unitary) real form of G, that is, the fixed point subgroup of the
lifting of $\omega$ to G. We construct a K-equivariant embedding of the twin
building of G into the lightcone of the compact real form k of g. Our embedding
gives a geometric model of part of the twin building, where each half consists
of infinitely many copies of a W-tessellated hyperbolic space glued together
along hyperplanes of the faces. Locally, at each such face, we find an
$SU(2)$-orbit of chambers stabilized by $U(1)$ which is thus parametrized by a
Riemann sphere $SU(2)/U(1)\cong S^2$. For n = 2 the twin building is a twin
tree. In this case, we construct our embedding explicitly and we describe the
action of the real root groups on the fundamental twin apartment. We also
construct a spherical twin building at infinity, and construct an embedding of
it into the set of rays on the boundary of the lightcone.


title: Symmetric Sums of Squares over $k$-Subset Hypercubes

abstract:
  We consider the problem of finding sum of squares (sos) expressions to
establish the non-negativity of a symmetric polynomial over a discrete
hypercube whose coordinates are indexed by the $k$-element subsets of $[n]$.
For simplicity, we focus on the case $k=2$, but our results extend naturally to
all values of $k \geq 2$. We develop a variant of the Gatermann-Parrilo
symmetry-reduction method tailored to our setting that allows for several
simplifications and a connection to flag algebras.
  We show that every symmetric polynomial that has a sos expression of a fixed
degree also has a succinct sos expression whose size depends only on the degree
and not on the number of variables. Our method bypasses much of the technical
difficulties needed to apply the Gatermann-Parrilo method, and offers
flexibility in obtaining succinct sos expressions that are combinatorially
meaningful. As a byproduct of our results, we arrive at a natural
representation-theoretic justification for the concept of flags as introduced
by Razborov in his flag algebra calculus. Furthermore, this connection exposes
a family of non-negative polynomials that cannot be certified with any fixed
set of flags, answering a question of Razborov in the context of our finite
setting.


title:
A model-based approach to the spatial and spectral calibration of
  NIRSpec onboard JWST

abstract:
  Context: The NIRSpec instrument for the James Webb Space Telescope (JWST) can
be operated in multiobject (MOS), long-slit, and integral field (IFU) mode with
spectral resolutions from 100 to 2700. Its MOS mode uses about a quarter of a
million individually addressable minislits for object selection, covering a
field of view of $\sim$9 $\mathrm{arcmin}^2$. Aims: The pipeline used to
extract wavelength-calibrated spectra from NIRSpec detector images relies
heavily on a model of NIRSpec optical geometry. We demonstrate how dedicated
calibration data from a small subset of NIRSpec modes and apertures can be used
to optimize this parametric model to the necessary levels of fidelity. Methods:
Following an iterative procedure, the initial fiducial values of the model
parameters are manually adjusted and then automatically optimized, so that the
model predicted location of the images and spectral lines from the fixed slits,
the IFU, and a small subset of the MOS apertures matches their measured
location in the main optical planes of the instrument. Results: The NIRSpec
parametric model is able to reproduce the spatial and spectral position of the
input spectra with high fidelity. The intrinsic accuracy (1-sigma, RMS) of the
model, as measured from the extracted calibration spectra, is better than 1/10
of a pixel along the spatial direction and better than 1/20 of a resolution
element in the spectral direction for all of the grating-based spectral modes.
This is fully consistent with the corresponding allocation in the spatial and
spectral calibration budgets of NIRSpec.


title: Layered social influence promotes multiculturality in the Axelrod model

abstract:
  Why is our society multicultural? Based on the two mechanisms of homophily
and social influence, the classical model for the dissemination of cultures
proposed by Axelrod predicts the existence of a fragmented regime where
different cultures can coexist in a social network. However, in such model the
multicultural regime is achievable only when a high number of cultural traits
is present, and is not robust against cultural drift, i.e. the spontaneous
mutations of agents' traits. In real systems, social influence is inherently
organised in layers, meaning that individuals tend to diversify their
connections according to the topic on which they interact. In this work we show
that the observed persistence of multiculturality in real-world social systems
is a natural consequence of the layered organisation of social influence. We
find that the critical number of cultural traits that separates the
monocultural and the multicultural regimes depends on the redundancy of
pairwise connections across layers. Surprisingly, for low values of structural
redundancy the system is always in a multicultural state, independently on the
number of traits, and is robust to the presence of cultural drift. Moreover, we
show that layered social influence allows the coexistence of different levels
of consensus on different topics. The insight obtained from simulations on
synthetic graphs are confirmed by the analysis of two real-world social
networks, where the multicultural regime persists even for a very small number
of cultural traits, suggesting that the layered organisation of social
interactions might indeed be at the heart of multicultural societies.


title: Balancing New Against Old Information: The Role of Surprise in Learning

abstract:
  Surprise describes a range of phenomena from unexpected events to behavioral
responses. We propose a measure of surprise and use it for surprise-driven
learning. Our surprise measure takes into account data likelihood as well as
the degree of commitment to a belief via the entropy of the belief
distribution. We find that surprise-minimizing learning dynamically adjusts the
balance between new and old information without the need of knowledge about the
temporal statistics of the environment. We apply our framework to a dynamic
decision-making task and a maze exploration task. Our surprise minimizing
framework is suitable for learning in complex environments, even if the
environment undergoes gradual or sudden changes and could eventually provide a
framework to study the behavior of humans and animals encountering surprising
events.


title:
Enhancement of the superconducting gap by nesting in CaKFe4As4 - a new
  high temperature superconductor

abstract:
  We use high resolution angle resolved photoemission spectroscopy and density
functional theory with experimentally obtained crystal structure parameters to
study the electronic properties of CaKFe4As4. In contrast to related CaFe2As2
compounds, CaKFe4As4 has high Tc of 35K at stochiometric composition. This
presents unique opportunity to study properties of high temperature
superconductivity of iron arsenic superconductors in absence of doping or
substitution. The Fermi surface consists of three hole pockets at $\Gamma$ and
two electron pockets at the $M$ point. We find that the values of the
superconducting gap are nearly isotropic, but significantly different for each
of the FS sheets. Most importantly we find that the overall momentum dependence
of the gap magnitudes plotted across the entire Brillouin zone displays a
strong deviation from the simple cos(kx)cos(ky) functional form of the gap
function, proposed in the scenario of the Cooper-pairing driven by a short
range antiferromagnetic exchange interaction. Instead, the maximum value of the
gap is observed for FS sheets that are closest to the ideal nesting condition
in contrast to the previous observations in some other ferropnictides. These
results provide strong support for the multiband character of superconductivity
in CaKFe4As4, in which Cooper pairing forms on the electron and the hole bands
interacting via dominant interband repulsive interaction, enhanced by FS
nesting}.


title:
Near-Horizon Geometry and the Entropy of a Minimally Coupled Scalar
  Field in the Kerr Black Hole

abstract:
  In this article we will discuss a Lorentzian sector calculation of the
entropy of a minimally coupled scalar field in the Kerr black hole background.
We will use the brick wall model of t' Hooft. In the Kerr black hole,
complications arise due to the absence of a global timelike Killing field and
the presence of the ergosphere. Nevertheless, it is possible to calculate the
entropy of a thin shell of matter field in the near-horizon region using the
brick wall model. The corresponding leading order entropy of the
nonsuperradiant modes is found to be proportional to the area of the horizon
and is logarithmically divergent. Thus, the entropy of a three dimensional
system in the near-horizon region is proportional to the boundary surface. This
is similar to that of the black hole entropy itself. The corresponding internal
energy remains finite if the entropy is chosen to be of the order of the black
hole entropy itself. For a fixed value of the brick wall cut-off, the leading
order entropy in the Kerr black hole is found to be half of the corresponding
term in the Schwarzschild black hole. This is consistent with the preferential
emission of particles in the Kerr black hole with azimuthal angular momentum in
the same direction as that of the black hole itself. However, we can obtain the
Schwarzschild case expression by including a subleading term and taking the
appropriate limit. The results obtained in this article may be relevant to
entropy bound and holographic principle.


title: The GlueX DIRC Project

abstract:
  The GlueX experiment was designed to search for and study the pattern of
gluonic excitations in the meson spectrum produced through photoproduction
reactions at a new tagged photon beam facility in Hall D at Jefferson
Laboratory. The particle identification capabilities of the GlueX experiment
will be enhanced by constructing a DIRC (Detection of Internally Reflected
Cherenkov light) detector, utilizing components of the decommissioned BaBar
DIRC. The DIRC will allow systematic studies of kaon final states that are
essential for inferring the quark flavor content of both hybrid and
conventional mesons. The design for the GlueX DIRC is presented, including the
new expansion volumes that are currently under development.


title: Measuring protoplanetary disk gas surface density profiles with ALMA

abstract:
  The gas and dust are spatially segregated in protoplanetary disks due to the
vertical settling and radial drift of large grains. A fuller accounting of the
mass content and distribution in disks therefore requires spectral line
observations. We extend the modeling approach presented in Williams & Best
(2014) to show that gas surface density profiles can be measured from high
fidelity 13CO integrated intensity images. We demonstrate the methodology by
fitting ALMA observations of the HD 163296 disk to determine a gas mass, Mgas =
0.048 solar masse, and accretion disk characteristic size Rc = 213au and
gradient gamma = 0.39. The same parameters match the C18O 2--1 image and
indicates an abundance ratio [13CO]/[C18O] of 700 independent of radius. To
test how well this methodology can be applied to future line surveys of
smaller, lower mass T Tauri disks, we create a large 13CO 2--1 image library
and fit simulated data. For disks with gas masses 3-10 Jupiter masses at 150pc,
ALMA observations with a resolution of 0.2-0.3 arcseconds and integration times
of about 20 minutes allow reliable estimates of Rc to within about 10au and
gamma to within about 0.2. Economic gas imaging surveys are therefore feasible
and offer the opportunity to open up a new dimension for studying disk
structure and its evolution toward planet formation.


title:
Collective Decision Dynamics in Group Evacuation: Behavioral Experiment
  and Machine Learning Models

abstract:
  Identifying factors that affect human decision making and quantifying their
influence remain essential and challenging tasks for the design and
implementation of social and technological communication systems. We report
results of a behavioral experiment involving decision making in the face of an
impending natural disaster. In a controlled laboratory setting, we characterize
individual and group evacuation decision making influenced by several key
factors, including the likelihood of the disaster, available shelter capacity,
group size, and group decision protocol. Our results show that success in
individual decision making is not a strong predictor of group performance. We
use an artificial neural network trained on the collective behavior of subjects
to predict individual and group outcomes. Overall model accuracy increases with
the inclusion of a subject-specific performance parameter based on laboratory
trials that captures individual differences. In parallel, we demonstrate that
the social media activity of individual subjects, specifically their Facebook
use, can be used to generate an alternative individual personality profile that
leads to comparable model accuracy. Quantitative characterization and
prediction of collective decision making is crucial for the development of
effective policies to guide the action of populations in the face of threat or
uncertainty.


title:
AGNfitter: A Bayesian MCMC approach to fitting spectral energy
  distributions of AGN

abstract:
  We present AGNfitter, a publicly available open-source algorithm implementing
a fully Bayesian Markov Chain Monte Carlo method to fit the spectral energy
distributions (SEDs) of active galactic nuclei (AGN) from the sub-mm to the UV,
allowing one to robustly disentangle the physical processes responsible for
their emission. AGNfitter makes use of a large library of theoretical,
empirical, and semi-empirical models to characterize both the nuclear and host
galaxy emission simultaneously. The model consists of four physical emission
components: an accretion disk, a torus of AGN heated dust, stellar populations,
and cold dust in star forming regions. AGNfitter determines the posterior
distributions of numerous parameters that govern the physics of AGN with a
fully Bayesian treatment of errors and parameter degeneracies, allowing one to
infer integrated luminosities, dust attenuation parameters, stellar masses, and
star formation rates. We tested AGNfitter's performace on real data by fitting
the SEDs of a sample of 714 X-ray selected AGN from the XMM-COSMOS survey,
spectroscopically classified as Type1 (unobscured) and Type2 (obscured) AGN by
their optical-UV emission lines. We find that two independent model parameters,
namely the reddening of the accretion disk and the column density of the dusty
torus, are good proxies for AGN obscuration, allowing us to develop a strategy
for classifying AGN as Type1 or Type2, based solely on an SED-fitting analysis.
Our classification scheme is in excellent agreement with the spectroscopic
classification, giving a completeness fraction of $\sim 86\%$ and $\sim 70\%$,
and an efficiency of $\sim 80\%$ and $\sim 77\%$, for Type1 and Type2 AGNs,
respectively.


title:
The Geometry of the Infrared and X-ray Obscurer in a Dusty Hyperluminous
  Quasar

abstract:
  We study the geometry of the AGN obscurer in IRAS 09104+4109, an IR-luminous,
radio-intermediate FR-I source at $z=0.442$, using infrared data from Spitzer
and Herschel, X-ray data from Nustar, Swift, Suzaku, and Chandra, and an
optical spectrum from Palomar. The infrared data imply a total rest-frame
1-1000$\mu$m luminosity of $5.5\times10^{46}$erg s$^{-1}$ and require both an
AGN torus and starburst model. The AGN torus has an anisotropy-corrected IR
luminosity of $4.9\times10^{46}$erg s$^{-1}$, and a viewing angle and half
opening angle both of approximately $36$ degrees from pole-on. The starburst
has a star formation rate of $(110\pm34)$M$_{\odot}$ yr$^{-1}$ and an age of
$<50$Myr. These results are consistent with two epochs of luminous activity in
09104: one approximately $150$Myr ago, and one ongoing. The X-ray data suggest
a photon index of $\Gamma \simeq 1.8$ and a line-of-sight column of $N_{\rm H}
\simeq 5\times10^{23}$cm$^{-2}$. This argues against a reflection-dominated
hard X-ray spectrum, which would have implied a much higher $N_{\rm H}$ and
luminosity. The X-ray and infrared data are consistent with a bolometric AGN
luminosity of $L_{\rm bol}\sim(0.5-2.5)\times10^{47}$erg s$^{-1}$. The X-ray
and infrared data are further consistent with coaligned AGN obscurers in which
the line of sight "skims" the torus. This is also consistent with the optical
spectra, which show both coronal iron lines and broad lines in polarized but
not direct light. Combining constraints from the X-ray, optical, and infrared
data suggests that the AGN obscurer is within a vertical height of $20$pc, and
a radius of $125$pc, of the nucleus.


title: Partial breakdown of quantum thermalization in a Hubbard-like model

abstract:
  We study the possible breakdown of quantum thermalization in a model of
itinerant electrons on a one-dimensional chain without disorder, with both spin
and charge degrees of freedom. The eigenstates of this model exhibit peculiar
properties in the entanglement entropy, the apparent scaling of which is
modified from a "volume law" to an "area law" after performing a partial,
site-wise measurement on the system. These properties and others suggest that
this model realizes a new, non-thermal phase of matter, known as a quantum
disentangled liquid (QDL). The putative existence of this phase has striking
implications for the foundations of quantum statistical mechanics.

categories: cond-mat.stat-mech cond-mat.mes-hall cond-mat.quant-gas cond-mat.str-el


title:
Chemical tagging with APOGEE: Discovery of a large population of N-rich
  stars in the inner Galaxy

abstract:
  Formation of globular clusters (GCs), the Galactic bulge, or galaxy bulges in
general, are important unsolved problems in Galactic astronomy. Homogeneous
infrared observations of large samples of stars belonging to GCs and the
Galactic bulge field are one of the best ways to study these problems. We
report the discovery by APOGEE of a population of field stars in the inner
Galaxy with abundances of N, C, and Al that are typically found in GC stars.
The newly discovered stars have high [N/Fe], which is correlated with [Al/Fe]
and anti-correlated with [C/Fe]. They are homogeneously distributed across, and
kinematically indistinguishable from, other field stars in the same volume.
Their metallicity distribution is seemingly unimodal, peaking at [Fe/H]~-1,
thus being in disagreement with that of the Galactic GC system. Our results can
be understood in terms of different scenarios. N-rich stars could be former
members of dissolved GCs, in which case the mass in destroyed GCs exceeds that
of the surviving GC system by a factor of ~8. In that scenario, the total mass
contained in so-called "first-generation" stars cannot be larger than that in
"second-generation" stars by more than a factor of ~9 and was certainly
smaller. Conversely, our results may imply the absence of a mandatory genetic
link between "second generation" stars and GCs. Last, but not least, N-rich
stars could be the oldest stars in the Galaxy, the by-products of chemical
enrichment by the first stellar generations formed in the heart of the Galaxy.


title: Symmetry protected gapless $Z_2$ spin liquids

abstract:
  Despite rapid progress in understanding gapped topological states, much less
is known about gapless topological phases of matter, especially in strongly
correlated electrons. In this work we discuss a large class of robust gapless
quantum spin liquids in frustrated magnets made of half-integer spins, which
are described by gapless fermionic spinons coupled to dynamical $Z_2$ gauge
fields. Requiring $U(1)$ spin conservation, time reversal and certain space
group symmetries, we show that certain spinon symmetry fractionalization class
necessarily leads to a gapless spectrum. These gapless excitations are stable
against any perturbations, as long as the required symmetries are preserved.
Applying these gapless criteria to spin one-half systems on square, triangular
and kagome lattices, we show that all gapped symmetric $Z_2$ spin liquids in
Abrikosov-fermion representation can also be realized in Schwinger-boson
representation. This leads to 64 gapped $Z_2$ spin liquids on square lattice,
and 8 gapped states on both kagome and triangular lattices.


title:
de Sitter vacua and supersymmetry breaking in six-dimensional flux
  compactifications

abstract:
  We consider six-dimensional supergravity with Abelian bulk flux compactified
on an orbifold. The effective low-energy action can be expressed in terms of
N=1 chiral moduli superfields with a gauged shift symmetry. The D-term
potential contains two Fayet-Iliopoulos terms which are induced by the flux and
by the Green-Schwarz term canceling the gauge anomalies, respectively. The
Green-Schwarz term also leads to a correction of the gauge kinetic function
which turns out to be crucial for the existence of Minkowski and de Sitter
vacua. Moduli stabilization is achieved by the interplay of the D-term and a
nonperturbative superpotential. Varying the gauge coupling and the
superpotential parameters, the scale of the extra dimensions can range from the
GUT scale down to the TeV scale. Supersymmetry is broken by F- and D-terms, and
the scale of gravitino, moduli, and modulini masses is determined by the size
of the compact dimensions.


title: Scale Invariant Dynamics and Universal Quantum Beats in Bose Gases

abstract:
  We study the signature of scale invariance in the far-from-equilibrium
quantum dynamics of two dimensional Bose gases. We show that the density
profile displays a scale invariant logarithmic singularity near the center. In
addition, the density oscillates due to quantum beats with universal
structures. Namely, the frequencies of the beats can be connected with one
another by a universal discrete scale transformation induced by the scale
invariance. The experimental applicability of these results is then discussed.


title: SN2002es-like Supernovae From Different Viewing Angles

abstract:
  In this letter, we compare optical light curves of two SN2002es-like Type Ia
supernovae, iPTF14atg and iPTF14dpk, from the intermediate Palomar Transient
Factory. Although the two light curves resemble each other around and after
maximum, they show distinct early-phase rise behavior in the $\textit{r}$-band.
On the one hand, iPTF14atg revealed a slow and steady rise which lasted for 22
days with a mean rise rate of $0.2\sim0.3\,\textrm{mag}\,\textrm{day}^{-1}$,
before it reached the $R$-band peak ($-18.05\,$mag). On the other hand,
iPTF14dpk rose rapidly to $-17\,$mag within a day of discovery with a rise rate
$>1.8\,\textrm{mag}\,\textrm{day}^{-1}$, and then rose slowly to its peak
($-18.19\,$mag) with a rise rate similar to iPTF14atg. The apparent total rise
time of iPTF14dpk is therefore only 16 days. We show that emission from
iPTF14atg before $-17\,$days with respect to its maximum can be entirely
attributed to radiation produced by collision between the SN and its companion
star. Such emission is absent in iPTF14dpk probably because of an unfavored
viewing angle, provided that SN2002es-like events arise from the same
progenitor channel. We further show that a SN2002es-like SN may experience a
dark phase after the explosion but before its radioactively powered light curve
becomes visible. This dark phase may be hidden by radiation from
supernova-companion interaction.


title:
Dynamic Model Averaging for Practitioners in Economics and Finance: The
  eDMA Package

abstract:
  Raftery, Karny, and Ettler (2010) introduce an estimation technique, which
they refer to as Dynamic Model Averaging (DMA). In their application, DMA is
used to predict the output strip thickness for a cold rolling mill, where the
output is measured with a time delay. Recently, DMA has also shown to be useful
in macroeconomic and financial applications. In this paper, we present the eDMA
package for DMA estimation implemented in R. The eDMA package is especially
suited for practitioners in economics and finance, where typically a large
number of predictors are available. Our implementation is up to 133 times
faster then a standard implementation using a single-core CPU. Thus, with the
help of this package, practitioners are able to perform DMA on a standard PC
without resorting to large clusters, which are not easily available to all
researchers. We demonstrate the usefulness of this package through simulation
experiments and an empirical application using quarterly U.S. inflation data.


title:
The XMM Cluster Outskirts Project (X-COP): Physical conditions to the
  virial radius of Abell 2142

abstract:
  Context. Galaxy clusters are continuously growing through the accretion of
matter in their outskirts. This process induces inhomogeneities in the gas
density distribution (clumping) which need to be taken into account to recover
the physical properties of the intracluster medium (ICM) at large radii. Aims.
We studied the thermodynamic properties in the outskirts (R > R500) of the
massive galaxy cluster Abell 2142 by combining the Sunyaev Zel'dovich (SZ)
effect with the X-ray signal. Methods. We combined the SZ pressure profile
measured by Planck with the XMM-Newton gas density profile to recover radial
profiles of temperature, entropy and hydrostatic mass out to 2R500. We used a
method that is insensitive to clumping to recover the gas density, and we
compared the results with traditional X-ray measurement techniques. Results.
When taking clumping into account, our joint SZ/X-ray entropy profile is
consistent with the predictions from pure gravitational collapse, whereas a
significant entropy flattening is found when the effect of clumping is
neglected. The hydrostatic mass profile recovered using joint X-ray/SZ data
agrees with that obtained from spectroscopic X-ray measurements and with mass
reconstructions obtained through weak lensing and galaxy kinematics.
Conclusions. We found that clumping can explain the entropy flattening observed
by Suzaku in the outskirts of several clusters. When using a method insensitive
to clumping for the reconstruction of the gas density, the thermodynamic
properties of Abell 2142 are compatible with the assumption that the thermal
gas pressure sustains gravity and that the entropy is injected at accretion
shocks, with no need to evoke more exotic physics. Our results highlight the
need for X-ray observations with sufficient spatial resolution, and large
collecting area, to understand the processes at work in cluster outer regions.


title:
The basis function approach for modeling autocorrelation in ecological
  data

abstract:
  Analyzing ecological data often requires modeling the autocorrelation created
by spatial and temporal processes. Many of the statistical methods used to
account for autocorrelation can be viewed as regression models that include
basis functions. Understanding the concept of basis functions enables
ecologists to modify commonly used ecological models to account for
autocorrelation, which can improve inference and predictive accuracy.
Understanding the properties of basis functions is essential for evaluating the
fit of spatial or time-series models, detecting a hidden form of
multicollinearity, and analyzing large data sets. We present important concepts
and properties related to basis functions and illustrate several tools and
techniques ecologists can use when modeling autocorrelation in ecological data.


title: Restriction, subadditivity, and semicontinuity theorems for Hodge ideals

abstract:
  We prove results concerning the behavior of Hodge ideals under restriction to
hypersurfaces or fibers of morphisms, and addition. The main tool is the
description of restriction functors for mixed Hodge modules by means of the
$V$-filtration.


title: Greedy palindromic lengths

abstract:
  In [A. Frid, S. Puzynina, L.Q. Zamboni, \textit{On palindromic factorization
of words}, Adv. in Appl. Math. 50 (2013), 737-748], it was conjectured that any
infinite word whose palindromic lengths of factors are bounded is ultimately
periodic. We introduce variants of this conjecture and prove this conjecture in
particular cases. Especially we introduce left and right greedy palindromic
lengths. These lengths are always greater than or equals to the initial
palindromic length. When the greedy left (or right) palindromic lengths of
prefixes of a word are bounded then this word is ultimately periodic.


title:
The Gaia-ESO survey: Hydrogen lines in red giants directly trace stellar
  mass

abstract:
  Red giant stars are perhaps the most important type of stars for Galactic and
extra-galactic archaeology: they are luminous, occur in all stellar
populations, and their surface temperatures allow precise abundance
determinations for many different chemical elements. Yet, the full star
formation and enrichment history of a galaxy can be traced directly only if two
key observables can be determined for large stellar samples - age and chemical
composition. While spectroscopy is a powerful method to analyse the detailed
abundances of stars, stellar ages are the "missing link in the chain", since
they are not a direct observable. However, spectroscopy should be able to
estimate stellar masses, which for red giants directly infer ages provided
their chemical composition is known.
  Here we establish a new empirical relation between the shape of the hydrogen
line in the observed spectra of red giants and stellar mass determined from
asteroseismology. The relation allows to determine stellar masses and ages with
the accuracy of 10-15%. The method can be used with confidence for stars in the
following range of stellar parameters: 4000 < Teff < 5000 K, 0.5 < log g < 3.5,
-2.0 < [Fe/H] < 0.3, and luminosities log L/LSun < 2.5. Our analysis provides
observational evidence that the Halpha spectral characteristics of red giant
stars are tightly correlated with their mass and therefore their age. We also
show that the method samples well all stellar populations with ages above 1
Gyr. Targeting bright giants, the method allows to obtain simultaneous age and
chemical abundance information far deeper than would be possible with
asteroseismology, extending the possible survey volume to remote regions of the
Milky Way and even to neighbouring galaxies like Andromeda or the Magellanic
Clouds already with present instrumentation, like VLT and Keck facilities.


title:
Non-standard interactions and the resolution of ordering of neutrino
  masses at DUNE and other long baseline experiments

abstract:
  In the era of precision neutrino physics, we study the influence of matter
NSI on the question of neutrino mass ordering and its resolution. At long
baseline experiments, since matter effects play a crucial role in addressing
this very important question, it is timely to investigate how sub-leading
effects due to NSI may affect and drastically alter inferences pertaining to
this question. We demonstrate that the sensitivity to mass ordering gets
significantly impacted due to NSI effects for various long baseline experiments
including the upcoming long baseline experiment, Deep Underground Neutrino
Experiment (DUNE). Finally we draw a comparison of DUNE, with the sensitivities
offered by two of the current neutrino beam experiments NOvA and T2K.


title: Driven quantum tunneling and pair creation with graphene Landau levels

abstract:
  Driven tunneling between graphene Landau levels is theoretically linked to
the process of pair creation from vacuum, a prediction of quantum
electrodynamics (QED). Landau levels are created by the presence of a strong,
constant, quantizing magnetic field perpendicular to a graphene mono-layer.
Following the formal analogy between QED and the description of low-energy
excitations in graphene, solutions of the fully interacting Dirac equation are
used to compute electron-hole pair creation driven by a circularly or linearly
polarized field. This is achieved via the coupled channel method, a numerical
scheme for the solution of the time-dependent Dirac equation in the presence of
bound states. The case of a monochromatic driving field is first considered,
followed by the more realistic case of a pulsed excitation. We show that the
pulse duration yields an experimental control parameter over the maximal pair
yield. Orders of magnitude of the pair yield are given for experimentally
achievable magnetic fields and laser intensities weak enough to preserve the
Landau level structure.


title:
Linear Classification of data with Support Vector Machines and
  Generalized Support Vector Machines

abstract:
  In this paper, we study the support vector machine and introduced the notion
of generalized support vector machine for classification of data. We show that
the problem of generalized support vector machine is equivalent to the problem
of generalized variational inequality and establish various results for the
existence of solutions. Moreover, we provide various examples to support our
results.


title: Perspectives on Multi-Level Dynamics

abstract:
  As Physics did in previous centuries, there is currently a common dream of
extracting generic laws of nature in economics, sociology, neuroscience, by
focalising the description of phenomena to a minimal set of variables and
parameters, linked together by causal equations of evolution whose structure
may reveal hidden principles. This requires a huge reduction of dimensionality
(number of degrees of freedom) and a change in the level of description. Beyond
the mere necessity of developing accurate techniques affording this reduction,
there is the question of the correspondence between the initial system and the
reduced one. In this paper, we offer a perspective towards a common framework
for discussing and understanding multi-level systems exhibiting structures at
various spatial and temporal levels. We propose a common foundation and
illustrate it with examples from different fields. We also point out the
difficulties in constructing such a general setting and its limitations.

categories: physics.soc-ph math-ph math.MP nlin.AO quant-ph


title:
Design and Implementation of a Novel Compatible Encoding Scheme in the
  Time Domain for Image Sensor Communication

abstract:
  This paper presents a modulation scheme in the time domain based on
On-Off-Keying and proposes various compatible supports for different types of
image sensors. The content of this article is a sub-proposal to the IEEE
802.15.7r1 Task Group (TG7r1) aimed at Optical Wireless Communication (OWC)
using an image sensor as the receiver. The compatibility support is
indispensable for Image Sensor Communications (ISC) because the rolling shutter
image sensors currently available have different frame rates, shutter speeds,
sampling rates, and resolutions. However, focusing on unidirectional
communications (i.e., data broadcasting, beacons), an asynchronous
communication prototype is also discussed in the paper. Due to the physical
limitations associated with typical image sensors (including low and varying
frame rates, long exposures, and low shutter speeds), the link speed
performance is critically considered. Based on the practical measurement of
camera response to modulated light, an operating frequency range is suggested
along with the similar system architecture, decoding procedure, and algorithms.
A significant feature of our novel data frame structure is that it can support
both typical frame rate cameras (in the oversampling mode) as well as very low
frame rate cameras (in the error detection mode for a camera whose frame rate
is lower than the transmission packet rate). A high frame rate camera, i.e., no
less than 20 fps, is supported in an oversampling mode in which a majority
voting scheme for decoding data is applied. A low frame rate camera, i.e., when
the frame rate drops to less than 20 fps at some certain time, is supported by
an error detection mode in which any missing data sub-packet is detected in
decoding and later corrected by external code. Numerical results and valuable
analysis are also included to indicate the capability of the proposed schemes.


title: In memoriam: Markus B\"uttiker (1950 - 2013)

abstract:
  Introduction for a special issue of Physica E dedicated to the memory of
Markus B\"uttiker.


title: Odd symmetry of least energy nodal solutions for the Choquard equation

abstract:
  We consider the Choquard equation (also known as stationary Hartree equation
or Schr\"odinger--Newton equation) \[
  -\Delta u + u = (I_\alpha \star |u|^p) |u|^{p - 2}u. \] Here $I_\alpha$
stands for the Riesz potential of order $\alpha \in (0,N)$, and $\frac{N - 2}{N
+ \alpha} < \frac{1}{p} \le \frac{1}{2}$. We prove that least energy nodal
solutions have an odd symmetry with respect to a hyperplane when $\alpha $ is
either close to $0$ or close to $N$.


title: Functors (between oo-categories) that aren't strictly unital

abstract:
  Let C and D be quasi-categories (a.k.a. infinity-categories). Suppose also
that one has an assignment sending commutative diagrams of C to commutative
diagrams of D which respects face maps, but not necessarily degeneracy maps.
(This is akin to having an assignment which respects all compositions, but may
not send identity morphisms to identity morphisms.) When does this assignment
give rise to an actual functor? We show that if the original assignment can be
shown to respect identity morphisms up to homotopy, then there exists an honest
functor of infinity-categories which respects the original assignments up to
homotopy. Moreover, we prove that such honest functors can be chosen naturally
with respect to the original assignments.


title: Discrete trigonometric and hyperbolic systems: An overview

abstract:
  In this paper we present an overview of results for discrete trigonometric
and hyperbolic systems. These systems are discrete analogues of trigonometric
and hyperbolic linear Hamiltonian systems. We show results which can be viewed
as discrete n-dimensional extensions of scalar continuous trigonometric and
hyperbolic formulas


title:
Uncertainties in the production of $p$ nuclei in massive stars obtained
  from Monte Carlo variations

abstract:
  Nuclear uncertainties in the production of $p$ nuclei in massive stars have
been quantified in a Monte Carlo procedure. Bespoke temperature-dependent
uncertainties were assigned to different types of reactions involving nuclei
from Fe to Bi. Their simultaneous impact was studied in postprocessing
explosive trajectories for three different stellar models. It was found that
the grid of mass zones in the model of a 25 $M_\odot$ star, which is widely
used for investigations of $p$ nucleosynthesis, is too crude to properly
resolve the detailed temperature changes required for describing the production
of $p$ nuclei. Using models with finer grids for 15 $M_\odot$ and 25 $M_\odot$
stars with initial solar metallicity, it was found that most of the production
uncertainties introduced by nuclear reaction uncertainties are smaller than a
factor of two. Since a large number of rates were varied at the same time in
the Monte Carlo procedure, possible cancellation effects of several
uncertainties could be taken into account. Key rates were identified for each
$p$ nucleus, which provide the dominant contribution to the production
uncertainty. These key rates were found by examining correlations between rate
variations and resulting abundance changes. This method is superior to studying
flow patterns, especially when the flows are complex, and to individual,
sequential variation of a few rates.


title: Interpretability in Linear Brain Decoding

abstract:
  Improving the interpretability of brain decoding approaches is of primary
interest in many neuroimaging studies. Despite extensive studies of this type,
at present, there is no formal definition for interpretability of brain
decoding models. As a consequence, there is no quantitative measure for
evaluating the interpretability of different brain decoding methods. In this
paper, we present a simple definition for interpretability of linear brain
decoding models. Then, we propose to combine the interpretability and the
performance of the brain decoding into a new multi-objective criterion for
model selection. Our preliminary results on the toy data show that optimizing
the hyper-parameters of the regularized linear classifier based on the proposed
criterion results in more informative linear models. The presented definition
provides the theoretical background for quantitative evaluation of
interpretability in linear brain decoding.


title:
User-Centric Mobility Management in Ultra-Dense Cellular Networks under
  Spatio-Temporal Dynamics

abstract:
  This article investigates the mobility management of an ultra dense cellular
network (UDN) from an energy-efficiency (EE) point of view. Many dormant base
stations (BSs) in a UDN do not transmit signals, and thus a received power
based handover (HO) approach as in traditional cellular networks is hardly
applicable. In addition, the limited front/backhaul capacity compared to a huge
number of BSs makes it difficult to implement a centralized HO and power
control. For these reasons, a novel user-centric association rule is proposed,
which jointly optimizes HO and power control for maximizing EE. The proposed
mobility management is able to cope not only with the spatial randomness of
user movement but also with temporally correlated wireless channels. The
proposed approach is implemented over a HO time window and tractable power
control policy by exploiting mean-field game (MFG) and stochastic geometry
(SG). Compared to a baseline with a fixed HO interval and transmit power, the
proposed approach achieves the 1.2 times higher long-term average EE at a
typical active BS.


title:
Kinetic models of collective decision-making in the presence of equality
  bias

abstract:
  We introduce and discuss kinetic models describing the influence of the
competence in the evolution of decisions in a multi-agent system. The original
exchange mechanism, which is based on the human tendency to compromise and
change opinion through self-thinking, is here modified to include the role of
the agents' competence. In particular, we take into account the agents'
tendency to behave in the same way as if they were as good, or as bad, as their
partner: the so-called equality bias. This occurred in a situation where a wide
gap separated the competence of group members. We discuss the main properties
of the kinetic models and numerically investigate some examples of collective
decision under the influence of the equality bias. The results confirm that the
equality bias leads the group to suboptimal decisions.


title:
DeepFood: Deep Learning-Based Food Image Recognition for Computer-Aided
  Dietary Assessment

abstract:
  Worldwide, in 2014, more than 1.9 billion adults, 18 years and older, were
overweight. Of these, over 600 million were obese. Accurately documenting
dietary caloric intake is crucial to manage weight loss, but also presents
challenges because most of the current methods for dietary assessment must rely
on memory to recall foods eaten. The ultimate goal of our research is to
develop computer-aided technical solutions to enhance and improve the accuracy
of current measurements of dietary intake. Our proposed system in this paper
aims to improve the accuracy of dietary assessment by analyzing the food images
captured by mobile devices (e.g., smartphone). The key technique innovation in
this paper is the deep learning-based food image recognition algorithms.
Substantial research has demonstrated that digital imaging accurately estimates
dietary intake in many environments and it has many advantages over other
methods. However, how to derive the food information (e.g., food type and
portion size) from food image effectively and efficiently remains a challenging
and open research problem. We propose a new Convolutional Neural Network
(CNN)-based food image recognition algorithm to address this problem. We
applied our proposed approach to two real-world food image data sets (UEC-256
and Food-101) and achieved impressive results. To the best of our knowledge,
these results outperformed all other reported work using these two data sets.
Our experiments have demonstrated that the proposed approach is a promising
solution for addressing the food image recognition problem. Our future work
includes further improving the performance of the algorithms and integrating
our system into a real-world mobile and cloud computing-based system to enhance
the accuracy of current measurements of dietary intake.


title:
Modal analysis of the scattering coefficients of an open cavity in a
  waveguide

abstract:
  The characteristics of an acoustic scatterer are often described by
scattering coefficients. The understanding of the mechanisms involved in the
frequency dependent features of the coefficients has been a challenge task,
owing to the complicated coupling between the waves in open space and the modes
inside the finite scatterer. In this paper, a frequency-dependent modal
description of the scattering coefficient is utilized to study the modal
properties of the scatterer. The important role that eigenmodes play in
defining the features of the scattering coefficients is revealed via an
expansion of the coefficients by the eigenmodes. The results show the local
extrema of the scattering coefficients can be attributed to the
constructive/destructive interference of resonant and non-resonant modes. In
particular, an approximated equation, which is equivalent to the standard Fano
formula, is obtained to describe the sharp anti-symmetric Fano characteristics
of the scattering coefficients. The special cases where scattering is dominated
by a single resonance eigenmode, corresponding to the "resonance transmission",
are also illustrated.


title:
A possible role of Alpha Crucis in the astronomical landscape of Silbury
  Hill

abstract:
  The paper is proposing a possible link between the construction of the
Silbury Hill, the prehistoric artificial mound near Avebury, and the
observation of Alpha Crucis, the main star of the Crux constellation, which was
slowly disappearing from the local sky due to the precession of the Earth's
axis. For the discussion, we used simulations of the local astronomical
landscape made by means of Stellarium software.