title:
On the penalized maximum likelihood estimation of high-dimensional
  approximate factor model

abstract:
  In this paper, we mainly focus on the penalized maximum likelihood estimation
(MLE) of the high-dimensional approximate factor model. Since the current
estimation procedure can not guarantee the positive definiteness of the error
covariance matrix, by reformulating the estimation of error covariance matrix
and based on the lagrangian duality, we propose an accelerated proximal
gradient (APG) algorithm to give a positive definite estimate of the error
covariance matrix. Combined the APG algorithm with EM method, a new estimation
procedure is proposed to estimate the high-dimensional approximate factor
model. The new method not only gives positive definite estimate of error
covariance matrix but also improves the efficiency of estimation for the
high-dimensional approximate factor model. Although the proposed algorithm can
not guarantee a global unique solution, it enjoys a desirable non-increasing
property. The efficiency of the new algorithm on estimation and forecasting is
also investigated via simulation and real data analysis.


title:
Conditional stability for an inverse source problem for the
  time-fractional diffusion equation

abstract:
  This paper deals with an inverse source problem for the $1$D time-fractional
diffusion equation by using boundary measurement. The conditional stability in
identification of the unknown source term is proved on the basis of the Fourier
transform and several properties of the Mittag-Leffler functions.


title: Th\'eor\`eme de Gabber d'ind\'ependance de $l$

abstract:
  We present Gabber's theorem of independence of $l$ for the intersection
cohomology of a proper equidimensional scheme over the spectrum of a finite
field. We follow [Fuji] very closely.
  -----
  On expose ici le th\'eor\`eme de Gabber d'ind\'ependance de $l$ pour la
cohomologie d'intersection d'un sch\'ema propre \'equidimensionnel sur le
spectre d'un corps fini. On suit [Fuji] \`a tr\`es peu pr\`es.


title: Efficient Continuous Relaxations for Dense CRF

abstract:
  Dense conditional random fields (CRF) with Gaussian pairwise potentials have
emerged as a popular framework for several computer vision applications such as
stereo correspondence and semantic segmentation. By modeling long-range
interactions, dense CRFs provide a more detailed labelling compared to their
sparse counterparts. Variational inference in these dense models is performed
using a filtering-based mean-field algorithm in order to obtain a
fully-factorized distribution minimising the Kullback-Leibler divergence to the
true distribution. In contrast to the continuous relaxation-based energy
minimisation algorithms used for sparse CRFs, the mean-field algorithm fails to
provide strong theoretical guarantees on the quality of its solutions. To
address this deficiency, we show that it is possible to use the same filtering
approach to speed-up the optimisation of several continuous relaxations.
Specifically, we solve a convex quadratic programming (QP) relaxation using the
efficient Frank-Wolfe algorithm. This also allows us to solve
difference-of-convex relaxations via the iterative concave-convex procedure
where each iteration requires solving a convex QP. Finally, we develop a novel
divide-and-conquer method to compute the subgradients of a linear programming
relaxation that provides the best theoretical bounds for energy minimisation.
We demonstrate the advantage of continuous relaxations over the widely used
mean-field algorithm on publicly available datasets.


title:
The fossil wind structures of Eta Carinae: changes across on 5.54-year
  cycle

abstract:
  Eta Carinae, the closest, active, massive binary containing a highly unstable
LBV, exhibits expanding, compressed wind shells, seen in emission, that are
spatially and spectrally resolved by \hst/\stis. Starting in June 2009, these
structures were mapped across its 5.54-year, highly elliptical, binary orbit to
follow temporal changes in the light of [Fe~III] 4659\AA\ and [Fe~II] 4815\AA.
The emissions trace portions of fossil wind-shells, that were formed by
wind-wind interactions across each cycle. Over the high-ionization state, dense
arcs, photo-ionized by far ultraviolet radiation from the hot secondary, are
seen in [Fe~III]. Other arcs, ionized by mid-ultraviolet radiation from the
primary star, are seen in [Fe II]. The [Fe III] structures tend to be interior
to [Fe II] structures that trace extensive, less disturbed primary wind. During
the brief periastron passage when the secondary plunges deep into the primary's
extremely dense wind, on the far side of primary star, high-ionization [Fe III]
structures fade and reappear in [Fe II]. Multiple fossil wind-structures were
traced across the 5.7-year monitoring interval. The strong similarity of the
expanding [Fe II] shells suggests that the wind and photo-ionization properties
of the massive binary have not changed substantially from one orbit to the next
over the past several orbital cycles. These observations trace structures that
can be used to test three-dimensional hydrodynamical and radiative-transfer
models of massive, interacting winds. They also provide a baseline for
following future changes in Eta Carinae, especially of its winds and
photoionization properties.


title:
Understanding molecular representations in machine learning: The role of
  uniqueness and target similarity

abstract:
  The predictive accuracy of Machine Learning (ML) models of molecular
properties depends on the choice of the molecular representation. Based on the
postulates of quantum mechanics, we introduce a hierarchy of representations
which meet uniqueness and target similarity criteria. To systematically control
target similarity, we rely on interatomic many body expansions, as implemented
in universal force-fields, including Bonding, Angular, and higher order terms
(BA). Addition of higher order contributions systematically increases
similarity to the true potential energy and predictive accuracy of the
resulting ML models. We report numerical evidence for the performance of BAML
models trained on molecular properties pre-calculated at electron-correlated
and density functional theory level of theory for thousands of small organic
molecules. Properties studied include enthalpies and free energies of
atomization, heatcapacity, zero-point vibrational energies, dipole-moment,
polarizability, HOMO/LUMO energies and gap, ionization potential, electron
affinity, and electronic excitations. After training, BAML predicts energies or
electronic properties of out-of-sample molecules with unprecedented accuracy
and speed.


title: Fluid Flows driven by Oscillating Body Force

abstract:
  In this note we consider general formulation of Euler's equations for an
inviscid incompressible homogeneous fluid with an oscillating body force. Our
aim is to derive the averaged equations for these flows with the help of
two-timing method. Our main result is the general and simple form of the
equation describing the averaged flows, which are derived without making any
additional assumptions. The presented results can have many interesting
applications.


title:
A Framework for the Construction of Generative Models for Mesoscale
  Structure in Multilayer Networks

abstract:
  Multilayer networks allow one to represent diverse and coupled connectivity
patterns --- e.g., time-dependence, multiple subsystems, or both --- that arise
in many applications and which are difficult or awkward to incorporate into
standard network representations. In the study of multilayer networks, it is
important to investigate mesoscale (i.e., intermediate-scale) structures, such
as dense sets of nodes known as communities, to discover network features that
are not apparent at the microscale or the macroscale. The ill-defined nature of
mesoscale structure and its ubiquity in empirical networks make it crucial to
develop generative models that can produce the features that one encounters in
empirical networks. Key purposes of such generative models include generating
synthetic networks with empirical properties of interest, benchmarking
mesoscale-detection methods and algorithms, and inferring structure in
empirical multilayer networks. In this paper, we introduce a framework for the
construction of generative models for mesoscale structures in multilayer
networks. Our framework provides a standardized set of generative models,
together with an associated set of principles from which they are derived, for
studies of mesoscale structures in multilayer networks. It unifies and
generalizes many existing models for mesoscale structures in fully-ordered
(e.g., temporal) and unordered (e.g., multiplex) multilayer networks. One can
also use it to construct generative models for mesoscale structures in
partially-ordered multilayer networks (e.g., networks that are both temporal
and multiplex). Our framework has the ability to produce many features of
empirical multilayer networks, and it explicitly incorporates a user-specified
dependency structure between layers.

categories: cs.SI cond-mat.stat-mech nlin.AO physics.soc-ph stat.ME


title: CrowdNet: A Deep Convolutional Network for Dense Crowd Counting

abstract:
  Our work proposes a novel deep learning framework for estimating crowd
density from static images of highly dense crowds. We use a combination of deep
and shallow, fully convolutional networks to predict the density map for a
given crowd image. Such a combination is used for effectively capturing both
the high-level semantic information (face/body detectors) and the low-level
features (blob detectors), that are necessary for crowd counting under large
scale variations. As most crowd datasets have limited training samples (<100
images) and deep learning based approaches require large amounts of training
data, we perform multi-scale data augmentation. Augmenting the training samples
in such a manner helps in guiding the CNN to learn scale invariant
representations. Our method is tested on the challenging UCF_CC_50 dataset, and
shown to outperform the state of the art methods.


title: Quantum Control Landscapes Are Almost Always Trap Free

abstract:
  A proof that almost all quantum systems have trap free (that is, free from
local optima) landscapes is presented for a large and physically general class
of quantum system. This result offers an explanation for why gradient methods
succeed so frequently in quantum control in both theory and practice. The role
of singular controls is analyzed using geometric tools in the case of the
control of the propagator of closed finite dimension systems. This type of
control field has been implicated as a source of landscape traps. The
conditions under which singular controls can introduce traps, and thus
interrupt the progress of a control optimization, are discussed and a
geometrical characterization of the issue is presented. It is shown that a
control being singular is not sufficient to cause a control optimization
progress to halt and sufficient conditions for a trap free landscape are
presented. It is further shown that the local surjectivity axiom of landscape
analysis can be refined to the condition that the end-point map is transverse
to each of the level sets of the fidelity function. This novel condition is
shown to be sufficient for a quantum system's landscape to be trap free. The
control landscape for a quantum system is shown to be trap free for all but a
null set of Hamiltonians using a novel geometric technique based on the
parametric transversality theorem. Numerical evidence confirming this is also
presented. This result is the analogue of the work of Altifini, wherein it is
shown that controllability holds for all but a null set of quantum systems in
the dipole approximation. The presented results indicate that by-and-large
limited control resources are the most physically relevant source of landscape
traps.


title: Emptying Dirac valleys in bismuth using high magnetic fields

abstract:
  The Fermi surface of elemental bismuth consists of three small rotationally
equivalent electron pockets, offering a valley degree of freedom to charge
carriers. A relatively small magnetic field can confine electrons to their
lowest Landau level. This is the quantum limit attained in other dilute metals
upon application of sufficiently strong magnetic field. Here, we report on the
observation of another threshold magnetic field never encountered before in any
other solid. Above this field, $B_{\rm{empty}}$, one or two valleys become
totally empty. Drying up a Fermi sea by magnetic field in the Brillouin zone
leads to a manyfold enhancement in electric conductance. We trace the origin of
the large drop in magnetoresistance across $B_{\rm{empty}}$ to transfer of
carriers between valleys with highly anisotropic mobilities. The
non-interacting picture of electrons with field-dependent mobility explains
most results. Coulomb interaction may play a role in shaping the fine details.


title:
Structural Transitions and Hysteresis in Clump- and Stripe-Forming
  Systems Under Dynamic Compression

abstract:
  Using numerical simulations, we study the dynamical evolution of particles
interacting via competing long-range repulsion and short-range attraction in
two dimensions. The particles are compressed using a time-dependent quasi-one
dimensional trough potential that controls the local density, causing the
system to undergo a series of structural phase transitions from a low density
clump lattice to stripes, voids, and a high density uniform state. The
compression proceeds via slow elastic motion that is interrupted with
avalanche-like bursts of activity as the system collapses to progressively
higher densities via plastic rearrangements. The plastic events vary in
magnitude from small rearrangements of particles, including the formation of
quadrupole-like defects, to large-scale vorticity and structural phase
transitions. In the dense uniform phase, the system compresses through row
reduction transitions mediated by a disorder-order process. We characterize the
rearrangement events by measuring changes in the potential energy, the fraction
of sixfold coordinated particles, the local density, and the velocity
distribution. At high confinements, we find power law scaling of the velocity
distribution during row reduction transitions. We observe hysteresis under a
reversal of the compression when relatively few plastic rearrangements occur.
The decompressing system exhibits distinct phase morphologies, and the phase
transitions occur at lower compression forces as the system expands compared to
when it is compressed.


title: Effective Distances for Epidemics Spreading on Complex Networks

abstract:
  We show that the recently introduced logarithmic metrics used to predict
disease arrival times on complex networks are approximations of more general
network-based measures derived from random walks theory. Using the daily
air-traffic transportation data we perform numerical experiments to compare the
infection arrival time with this alternative metric that is obtained by
accounting for multiple walks instead of only the most probable path. The
comparison with direct simulations of arrival times reveals a higher
correlation compared to the shortest path approach used previously. In addition
our method allows to connect fundamental observables in epidemic spreading with
the cumulant generating function of the hitting time for a Markov chain. Our
results provides a general and computationally efficient approach to the
problem using only algebraic methods.


title:
Properties and evolution of anisotropic structures in collisionless
  plasmas

abstract:
  A new class of exact electrostatic solutions of the Vlasov-Maxwell equations
based on the Jeans's theorem is proposed for studying the evolution and
properties of two-dimensional anisotropic plasmas that are far from
thermodynamic equilibrium. In particular, the free expansion of a slab of
electron-ion plasma into vacuum is investigated.


title: Computational and Statistical Tradeoffs in Learning to Rank

abstract:
  For massive and heterogeneous modern datasets, it is of fundamental interest
to provide guarantees on the accuracy of estimation when computational
resources are limited. In the application of learning to rank, we provide a
hierarchy of rank-breaking mechanisms ordered by the complexity in thus
generated sketch of the data. This allows the number of data points collected
to be gracefully traded off against computational resources available, while
guaranteeing the desired level of accuracy. Theoretical guarantees on the
proposed generalized rank-breaking implicitly provide such trade-offs, which
can be explicitly characterized under certain canonical scenarios on the
structure of the data.


title:
Towards the Interactive Effects of Demand Response Participation on
  Electricity Spot Market Price

abstract:
  The electricity market is threatened by supply scarcity, which may lead to
very sharp price spikes in the spot market. On the other hand, demand-side's
activities could effectively mitigate the supply scarcity and absorb most of
these shocks and therefore smooth out the price volatility. In this paper, the
positive effects of employing demand response programs on the spot market price
are investigated. A demand-price elasticity based model is used to simulate the
customer reaction function in the presence of a real time pricing. The demand
achieve by DR program is used to adjust the spot market price by using a price
regression model. SAS software is used to run the multiple linear regression
model and MATLAB is used to simulate the demand response model. The approach is
applied on one week data in summer 2014 of Connecticut in New England ISO. It
could be concluded from the results of this study that applying DR program
smooths out most of the price spikes in the electricity spot market and
considerably reduces the customers' electricity cost.


title:
Model analysis of magnetic susceptibility of Sr$_2$IrO$_4$ - 2D $J_{\rm
  eff}$ = 1/2 Heisenberg system with competing interlayer couplings

abstract:
  We report the analysis of magnetic susceptibility $\chi$($T$) of
Sr$_2$IrO$_4$ single crystal in the paramagnetic phase. We formulate the
theoretical susceptibility based on isotropic Heisenberg antiferromagnetism
incorporating the Dzyaloshinsky-Moriya interaction exactly, and include the
interlayer couplings in a mean-field approximation. $\chi$($T$) above $T_{\rm
N}$ was found to be well described by the model, indicating the predominant
Heisenberg exchange consistent with the microscopic theory. The analysis points
to a competition of nearest and next-nearest neighbor interlayer couplings,
which results in the up-up-down-down configuration of the in-plane canting
moments identified by the diffraction experiments.


title: Four-body Central Configurations with Adjacent Equal Masses

abstract:
  For any convex non-collinear central configuration of the planar Newtonian
4-body problem with adjacent equal masses $m_1=m_2\neq m_3=m_4$, with equal
lengths for the two diagonals, we prove it must possess a symmetry and must be
an isosceles trapezoid; furthermore, which is also an isosceles trapezoid when
the length between $m_1$ and $ m_4$ equals the length between $m_2$ and $ m_3$.


title: Snyder-type spaces, twisted Poincar\'e algebra and addition of momenta

abstract:
  We discuss a generalisation of the Snyder model that includes all the
possible deformations of the Heisenberg algebra compatible with Lorentz
invariance, in terms of realisations of the noncommutative geometry. The
corresponding deformed addition of momenta, the twist and the $R$-matrix are
calculated to first order in the deformation parameters for all models. In the
particular case of the Snyder realisation, the exact formula for the twist is
obtained.


title:
Two Forms of Proximal Physical Geometry. Axioms, Sewing Regions
  Together, Classes of Regions, Duality, and Parallel Fibre Bundles

abstract:
  This paper introduces two proximal forms of Lenzen physical geometry, namely,
an \emph{axiomatized strongly proximal physical geometry} that is built on
simplicial complexes with the dualities and sewing operations derived from
string geometry and an \emph{axiomatized descriptive proximal physical
geometry} in which spatial regions are described based on their features and
the descriptive proximities between regions. This is a computational proximity
approach to a Lenzen geometry of physical space. In both forms of physical
geometry, region is a primitive. Intuitively, a region is a set of connected
subregions. The primitive in this geometry is \emph{region}, instead of
\emph{point}. Each description of a region with $n$ features is a mapping from
the region to a feature vector in $\mathbb{R}^n$. In the feature space,
proximal physical geometry has the look and feel of either Euclidean,
Riemannian, or non-Euclidean geometry, since we freely work with the relations
between points in the feature space. The focus in these new forms of geometry
is the relation between individual regions with their own distinctive features
such as shape, area, perimeter and diameter and the relation between nonempty
sets of regions. The axioms for physical geometry as well as the axioms for
proximal physical geometry are given and illustrated. Results for parallel
classes of regions, descriptive fibre bundles and BreMiller-Sloyer sheaves are
given. In addition, a region-based Borsuk-Ulam Theorem as well as a Wired
Friend Theorem are given in the context of both forms of physical geometry.


title:
Bethe ansatz solution of the $\tau_2$-model with arbitrary boundary
  fields

abstract:
  The quantum $\tau_2$-model with generic site-dependent inhomogeneity and
arbitrary boundary fields is studied via the off-diagonal Bethe Ansatz method.
The eigenvalues of the corresponding transfer matrix are given in terms of an
inhomogeneous T-Q relation, which is based on the operator product identities
among the fused transfer matrices and the asymptotic behavior of the transfer
matrices. Moreover, the associated Bethe Ansatz equations are also obtained.

categories: math-ph cond-mat.stat-mech hep-th math.MP


title: $\sigma$-Ideals and outer measures on the real line

abstract:
  A {\it weak selection} on $\mathbb{R}$ is a function $f: [\mathbb{R}]^2 \to
\mathbb{R}$ such that $f(\{x,y\}) \in \{x,y\}$ for each $\{x,y\} \in
[\mathbb{R}]^2$. In this article, we continue with the study (which was
initiated in \cite{ag}) of the outer measures $\lambda_f$ on the real line
$\mathbb{R}$ defined by weak selections $f$. One of the main results is to show
that $CH$ is equivalent to the existence of a weak selection $f$ for which: \[
\mathcal \lambda_f(A)= \begin{cases} 0 & \text{if $|A| \leq \omega$,}\\ \infty
& \text{otherwise.} \end{cases} \] Some conditions are given for a
$\sigma$-ideal of $\mathbb{R}$ in order to be exactly the family
$\mathcal{N}_f$ of $\lambda_f$-null subsets for some weak selection $f$. It is
shown that there are $2^\mathfrak{c}$ pairwise distinct ideals on $\mathbb{R}$
of the form $\mathcal{N}_f$, where $f$ is a weak selection. Also we prove that
Martin Axiom implies the existence of a weak selection $f$ such that
$\mathcal{N}_f$ is exactly the $\sigma$-ideal of meager subsets of
$\mathbb{R}$. Finally, we shall study pairs of weak selections which are
"almost equal" but they have different families of $\lambda_f$-measurable sets.


title:
{\cal N}=2 Supersymmetric quantum mechanics of N Lieb-Liniger-Yang
  bosons on a line

abstract:
  A supersymmetric generalization of the Lieb-Liniger-Yang dynamics governing
$N$ massive bosons moving on a line with delta interactions among them at
coinciding points is developed. The analysis of the delicate balance between
integrability and supersymmetry, starting from the exactly solvable non
supersymmetric LLY system, is one of the paper main concerns. Two extreme
regimes of the $N$ parameter are explored: 1) For few bosons we fall in the
realm of supersymmetric quantum mechanics with a short number of degrees of
freedom, e.g., the SUSY P$\ddot{\rm o}$sch-Teller potentials if $N=1$. 2) For
large $N$ we deal with supersymmetric extensions of many body systems in the
thermodynamic limit akin, e.g., to the supersymmetric Calogero-Sutherland
systems. Emphasis will be put in the investigation of the ground state
structure of these quantum mechanical systems enjoying ${\cal N}=2$ extended
supersymmetry without spoiling integrability. The decision about wether or not
supersymmetry is spontaneously broken, a central question in SUSY quantum
mechanics determined from the ground state structure, is another goal of the
paper.


title: Datatype defining rewrite systems for naturals and integers

abstract:
  A datatype defining rewrite system (DDRS) is an algebraic (equational)
specification intended to specify a datatype. When interpreting the equations
from left-to-right, a DDRS defines a term rewriting system that must be
ground-complete. First we define two DDRSs for the ring of integers, each
comprising twelve rewrite rules, and prove their ground-completeness. Then we
introduce natural number and integer arithmetic specified according to unary
view, that is, arithmetic based on a postfix unary append constructor (a form
of tallying). Next we specify arithmetic based on two other views: binary and
decimal notation. The binary and decimal view have as their characteristic that
each normal form resembles common number notation, that is, either a digit, or
a string of digits without leading zero, or the negated versions of the latter.
Integer arithmetic in binary and decimal notation is based on (postfix) digit
append functions. For each view we define a DDRS, and in each case the
resulting datatype is a canonical term algebra that extends a corresponding
canonical term algebra for natural numbers. Then, for each view, we consider an
alternative DDRS based on tree constructors that yields comparable normal
forms, which for that view admits expressions that are algorithmically more
involved. For all DDRSs considered, ground-completeness is proven.


title:
Dacorogna-Moser theorem on the Jacobian determinant equation with
  control of support

abstract:
  The original proof of Dacorogna-Moser theorem on the prescribed Jacobian PDE,
$\text{det}\,\nabla\varphi=f$, can be modified in order to obtain control of
support of the solutions from that of the initial data, while keeping optimal
regularity. Briefly, under the usual conditions, a solution diffeomorphism
$\varphi$ satisfying \[
\text{supp}(f-1)\subset\varOmega\Longrightarrow\text{supp}(\varphi-\text{id})\subset\varOmega
\] can be found and $\varphi$ is still of class $C^{r+1,\alpha}$ if $f$ is
$C^{r,\alpha}$, the domain of $f$ being a bounded connected open
$C^{r+2,\alpha}$ set $\varOmega\subset\mathbb{R}^{n}$.


title: Nonlocal elasticity near jamming

abstract:
  We demonstrate that the elasticity of jammed solids is nonlocal. By forcing
frictionless soft sphere packings at varying wavelength, we directly access
their transverse and longitudinal compliances without resorting to curve
fitting. The observed wavelength dependence of the compliances is incompatible
with classical (local) elasticity, and hence quantifies the amplitude of
nonlocal effects. Three distinct length scales, two of which diverge, control
the amplitude of both nonlocal effects and fluctuations about the mean
response. Our results identify new, more accurate constitutive relations for
weakly jammed solids, including emulsions, foams, and granulates.


title:
Maximal rank subgroups and strong functoriality of the additive
  eigencone

abstract:
  Let $G$ be a simple connected complex Lie group. The additive eigencone of
$G$ is a polyhedral cone containing the set of solutions to the additive
eigenvalue problem, a generalization of the Hermitian eigenvalue problem. The
additive eigencone is functorial, and for certain subgroups satisfies a
stronger functoriality property: the eigencone of the subgroup is determined by
the inequalities of the larger eigencone. Belkale and Kumar first studied this
property for subgroups invariant under a diagram automorphism of $G$. We study
a new class of subgroups arising from centralizers of torus elements that have
the strong eigencone functoriality property.


title:
The Magellan PFS Planet Search Program: Radial Velocity and Stellar
  Abundance Analyses of the 360 AU, Metal-Poor Binary "Twins" HD 133131A & B

abstract:
  We present a new precision radial velocity (RV) dataset that reveals multiple
planets orbiting the stars in the $\sim$360 AU, G2$+$G2 "twin" binary HD
133131AB. Our 6 years of high-resolution echelle observations from MIKE and 5
years from PFS on the Magellan telescopes indicate the presence of two
eccentric planets around HD 133131A with minimum masses of 1.43$\pm$0.03 and
0.63$\pm$0.15 $\mathcal{M}_{\rm J}$ at 1.44$\pm$0.005 and 4.79$\pm$0.92 AU,
respectively. Additional PFS observations of HD 133131B spanning 5 years
indicate the presence of one eccentric planet of minimum mass 2.50$\pm$0.05
$\mathcal{M}_{\rm J}$ at 6.40$\pm$0.59 AU, making it one of the longest period
planets detected with RV to date. These planets are the first to be reported
primarily based on data taken with PFS on Magellan, demonstrating the
instrument's precision and the advantage of long-baseline RV observations. We
perform a differential analysis between the Sun and each star, and between the
stars themselves, to derive stellar parameters and measure a suite of 21
abundances across a wide range of condensation temperatures. The host stars are
old (likely $\sim$9.5 Gyr) and metal-poor ([Fe/H]$\sim$-0.30), and we detect a
$\sim$0.03 dex depletion in refractory elements in HD 133131A versus B (with
standard errors $\sim$0.017). This detection and analysis adds to a small but
growing sample of binary "twin" exoplanet host stars with precise abundances
measured, and represents the most metal-poor and likely oldest in that sample.
Overall, the planets around HD 133131A and B fall in an unexpected regime in
planet mass-host star metallicity space and will serve as an important
benchmark for the study of long period giant planets.


title: Low Energy Clamped Planar Elastica

abstract:
  A method is given for estimating clamped plane elastica. Arguments are made,
and evidence is provided by way of illustrative examples, suggesting that the
new method is quicker and more robust than standard discretisation, and more
likely to give elastica of low energy. Just as for standard discretisation, no
use is made of the known solutions for elastica in terms of elliptic functions.


title: Circular motion in NUT space-time

abstract:
  We consider circular motion in the NUT (Newman-Unti-Tamburino) space-time.
Among other things, we determine the location of circular time-like geodesic
orbits, in particular of the innermost stable circular orbit (ISCO) and of the
marginally bound circular orbit. Moreover, we discuss the von Zeipel cylinders
with respect to the stationary observers and with respect to the Zero Angular
Momentum Observers (ZAMOs). We also investigate the relation of von Zeipel
cylinders to inertial forces, in particular in the ultra-relativistic limit.
Finally, we generalise the construction of thick accretion tori ("Polish
doughnuts") which are well known on the Schwarzschild or Kerr background to the
case of the NUT metric. We argue that, in principle, a NUT source could be
distinguished from a Schwarzschild or Kerr source by observing the features of
circular matter flows in its neighbourhood.


title: Precessing Jet in the High-Redshift Blazar J0017+8135

abstract:
  The prominent flat-spectrum radio quasar J0017+8135 (S5 0014+81) at z = 3.366
is one of the most luminous active galactic nuclei (AGN) known. Its
milliarcsecond-scale radio jet structure has been studied with very long
baseline interferometry (VLBI) since the 1980s. The quasar was selected as one
of the original defining objects of the International Celestial Reference
Frame, but left out from its current second realization (ICRF2) because of
systematic long-term positional variations. Here we analyse archival 8.6- and
2.3-GHz VLBI imaging data collected at nearly 100 different epochs during more
than 20 years, to obtain information about the kinematics of jet components.
Because of the cosmological time dilation, extensive VLBI monitoring data are
essential to reveal changes in the jet structure of high-redshift AGN. In the
case of J0017+8135, the data can be described with a simple kinematic model of
jet precession with a 12-year periodicity in the observer's frame.


title: A Note on the Quartic Diophantine Equation $A^4+hB^4=C^4+hD^4$

abstract:
  Integer solutions of the diophantine equation $A^4+hB^4=C^4+hD^4$ are known
for all positive integer values of $h < 1000$. While a solution of the
aforementioned diophantine equation for any arbitrary positive integer value of
$h$ is not known, Gerardin and Piezas found solutions of this equation when $h$
is given by polynomials of degrees 5 and 2 respectively. In this paper, we
present several new solutions of this equation when $h$ is given by polynomials
of degrees $2,\;3$ and 4.


title: Quantum channel-estimation with particle loss: GHZ versus W states

abstract:
  We consider quantum channel-estimation for depolarizing channels and
phase-flip channels extended by ancilla qubits and fed with a GHZ or W state.
After application of the channel one or several qubits can be lost, and we
calculate the impact of the loss on the quantum Fisher information that
determines the smallest uncertainty with which the parameters of these channels
can be estimated.


title:
Modeling the Influence of Local Environmental Factors on Malaria
  Transmission in Benin and Its Implications for Cohort Study

abstract:
  Malaria remains endemic in tropical areas, especially in Africa. For the
evaluation of new tools and to further ourunderstanding of host-parasite
interactions, knowing the environmental risk of transmission-even at a very
local scale-isessential. The aim of this study was to assess how malaria
transmission is influenced and can be predicted by local climaticand
environmental factors. As the entomological part of a cohort study of 650
newborn babies in nine villages in the ToriBossito district of Southern Benin
between June 2007 and February 2010, human landing catches were performed to
assessthe density of malaria vectors and transmission intensity. Climatic
factors as well as household characteristics were recordedthroughout the study.
Statistical correlations between Anopheles density and environmental and
climatic factors weretested using a three-level Poisson mixed regression model.
The results showed both temporal variations in vector density(related to season
and rainfall), and spatial variations at the level of both village and house.
These spatial variations could belargely explained by factors associated with
the house's immediate surroundings, namely soil type, vegetation index andthe
proximity of a watercourse. Based on these results, a predictive regression
model was developed using a leave-one-outmethod, to predict the spatiotemporal
variability of malaria transmission in the nine villages. This study points up
theimportance of local environmental factors in malaria transmission and
describes a model to predict the transmission risk ofindividual children, based
on environmental and behavioral characteristics.


title: Dissipative Axial Inflation

abstract:
  We analyze in detail the background cosmological evolution of a scalar field
coupled to a massless abelian gauge field through an axial term
$\frac{\phi}{f_\gamma} F \tilde{F}$, such as in the case of an axion. Gauge
fields in this case are known to experience tachyonic growth and therefore can
backreact on the background as an effective dissipation into radiation energy
density $\rho_R$, which which can lead to inflation without the need of a flat
potential. We analyze the system, for momenta $k$ smaller than the cutoff
$f_\gamma$, including numerically the backreaction. We consider the evolution
from a given static initial condition and explicitly show that, if $f_\gamma$
is smaller than the field excursion $\phi_0$ by about a factor of at least
${\cal O} (20)$, there is a friction effect which turns on before that the
field can fall down and which can then lead to a very long stage of inflation
with a generic potential. In addition we find superimposed oscillations, which
would get imprinted on any kind of perturbations, scalars and tensors. Such
oscillations have a period of 4-5 efolds and an amplitude which is typically
less than a few percent and decreases linearly with $f_\gamma$. We also stress
that the comoving curvature perturbation on uniform density should be sensitive
to slow-roll parameters related to $\rho_R$ rather than $\dot{\phi}^2/2$,
although we postpone a calculation of the power spectrum and of non-gaussianity
to future work and we simply define and compute suitable slow roll parameters.
Finally we stress that this scenario may be realized in the axion case, if the
coupling $1/f_\gamma$ to U(1) (photons) is much larger than the coupling
$1/f_G$ to non-abelian gauge fields (gluons), since the latter sets the range
of the potential and therefore the maximal allowed $\phi_0\sim f_G$.


title:
Improving the measurement of the CKM phase $\phi_2 = \alpha$ in $B \to
  \pi \pi$ and $B \to \rho \rho$ decays

abstract:
  CP-violating asymmetries in $B \to \pi \pi$ and $B \to \rho \rho$ decays can
help specify the weak phase $\phi_2 = \alpha$ of the Cabibbo-Kobayashi-%
Maskawa (CKM) matrix. We discuss the impact of improved measurements of these
processes such as will be available in the near future, finding special value
in better measurement of the time-dependent CP violation parameter $S_{00}$ in
$B^0 \to \pi^0 \pi^0$ and $B^0 \to \rho^0 \rho^0$. Reducing the errors on $B
\to \rho \rho$ measurements by a factor of two can potentially lead to an error
in $\phi_2 = \alpha$ just above $2^\circ$, at which level isospin-breaking
corrections must be considered.


title:
Remanent magnetization: signature of Many-Body Localization in quantum
  antiferromagnets

abstract:
  We study the remanent magnetization in antiferromagnetic, many-body localized
quantum spin chains, initialized in a fully magnetized state. Its long time
limit is an order parameter for the localization transition, which is readily
accessible by standard experimental probes in magnets. We analytically
calculate its value in the strong-disorder regime exploiting the explicit
construction of quasi-local conserved quantities of the localized phase. We
discuss analogies in cold atomic systems.


title:
Stability Analysis for Composite Optimization Problems and Parametric
  Variational Systems

abstract:
  This paper aims to provide various applications for second-order variational
analysis of extended-real-valued piecewise liner functions recently obtained in
[1]. We mainly focus here on establishing relationships between full stability
of local minimizers in composite optimization and Robinson's strong regularity
of associated (linearized and nonlinearized) KKT systems. Finally, we address
Lipschitzian stability of parametric variational systems with convex piecewise
linear potentials.


title:
Phonon-assisted indirect transitions in angle-resolved photoemission
  spectra of graphite and graphene

abstract:
  Indirect transitions of electrons in graphene and graphite are investigated
by means of angle-resolved photoemission spectroscopy (ARPES) with several
different incident photon energies and light polarizations. The theoretical
calculations of the indirect transition for graphene and graphite are compared
with the experimental measurements for highly-oriented pyrolytic graphite and a
single-crystal of graphite. The dispersion relations for the transverse optical
(TO) and the out-of-plane longitudinal acoustic (ZA) phonon modes of graphite
and the TO phonon mode of graphene can be extracted from the inelastic ARPES
intensity. We find that the TO phonon mode for $k$ points along the
$\Gamma$-$K$ and $K$-$M$-$K'$ directions in the Brillouin zone can be observed
in the ARPES spectra of graphite and graphene by using a photon energy of about
11.1 eV. The relevant mechanism in the ARPES process for this case is the
resonant indirect transition. On the other hand, the ZA phonon mode of graphite
can be observed by using a photon energy of about 6.3 eV through a nonresonant
indirect transition, while the ZA phonon mode of graphene within the same
mechanism should not be observed.


title: Absolutely maximally entangled states of seven qubits do not exist

abstract:
  Pure multiparticle quantum states are called absolutely maximally entangled
if all reduced states obtained by tracing out at least half of the particles
are maximally mixed. We provide a method to characterize these states for a
general multiparticle system. With that, we prove that a seven-qubit state
whose three-body marginals are all maximally mixed, or equivalently, a pure
$((7,1,4))_2$ quantum error correcting code, does not exist. Furthermore, we
obtain an upper limit on the possible number of maximally mixed three-body
marginals and identify the state saturating the bound. This solves the
seven-particle problem as the last open case concerning maximally entangled
states of qubits.


title: A Systematic Identification and Analysis of Scientists on Twitter

abstract:
  Metrics derived from Twitter and other social media---often referred to as
altmetrics---are increasingly used to estimate the broader social impacts of
scholarship. Such efforts, however, may produce highly misleading results, as
the entities that participate in conversations about science on these platforms
are largely unknown. For instance, if altmetric activities are generated mainly
by scientists, does it really capture broader social impacts of science? Here
we present a systematic approach to identifying and analyzing scientists on
Twitter. Our method can identify scientists across many disciplines, without
relying on external bibliographic data, and be easily adapted to identify other
stakeholder groups in science. We investigate the demographics, sharing
behaviors, and interconnectivity of the identified scientists. We find that
Twitter has been employed by scholars across the disciplinary spectrum, with an
over-representation of social and computer and information scientists;
under-representation of mathematical, physical, and life scientists; and a
better representation of women compared to scholarly publishing. Analysis of
the sharing of URLs reveals a distinct imprint of scholarly sites, yet only a
small fraction of shared URLs are science-related. We find an assortative
mixing with respect to disciplines in the networks between scientists,
suggesting the maintenance of disciplinary walls in social media. Our work
contributes to the literature both methodologically and conceptually---we
provide new methods for disambiguating and identifying particular actors on
social media and describing the behaviors of scientists, thus providing
foundational information for the construction and use of indicators on the
basis of social media metrics.


title:
On the existence, uniqueness and regularity of solutions of a
  viscoelastic Stokes problem modelling salt rocks

abstract:
  A Stokes-type problem for a viscoelastic model of salt rocks is considered,
and existence, uniqueness and regularity are investigated in the scale of
$L^2$-based Sobolev spaces. The system is transformed into a generalized Stokes
problem, and the proper conditions on the parameters of the model that
guarantee that the system is uniformly elliptic are given. Under those
conditions, existence, uniqueness and low-order regularity are obtained under
classical regularity conditions on the data, while higher-order regularity is
proved under less stringent conditions than classical ones. Explicit estimates
for the solution in terms of the data are given accordingly.


title:
NLO QCD Corrections for $J/\psi+ c + \bar{c}$ Production in
  Photon-Photon Collision

abstract:
  The $\gamma+\gamma\rightarrow J/\psi+c+\bar{c}$ inclusive process is an
extremely important subprocess in $J/\psi$ production via photon-photon
scattering, like at LEP\uppercase\expandafter{\romannumeral2} or various types
future electron-positron colliders. In this work we perform the
next-to-leading(NLO) QCD corrections to this process in the framework of
non-relativistic QCD(NRQCD) factorization formalism, the first NLO calculation
for two projectiles to 3-body quarkonium inclusive production process. By
setting the center-of-mass energy at LEP\uppercase\expandafter{\romannumeral2},
the $\sqrt{s}=197$ GeV, we conduct analyses of the $p_t^2$ distribution and
total cross section of this process at the NLO accuracy. It turns out that the
total cross section is moderately enhanced by the NLO correction with a $K$
factor of about 1.46, and hence the discrepancy between DELPHI data and
color-singlet(CS) calculation is reduced while the color-octet(CO)
contributions are still inevitable at this order. At the future Circular
Electron-Positron Collider(CEPC), the NLO corrections are found to be more
significant, with a $K$ factor of about 1.76.


title: An energy-capacity inequality for Legendrian submanifolds

abstract:
  We prove that the number of Reeb chords between a Legendrian submanifold and
its contact Hamiltonian push-off is at least the sum of the
$\mathbb{Z}_2$-Betti numbers of the submanifold, provided that the contact
isotopy is sufficiently small when compared to the smallest Reeb chord on the
Legendrian. Moreover, the established invariance enables us to use two
different contact forms: one for the count of Reeb chords and another for the
measure of the smallest length, under the assumption that there is a suitable
symplectic cobordism from the latter to the former. The size of the contact
isotopy is measured in terms of the oscillation of the contact Hamiltonian,
together with the maximal factor by which the contact form is shrunk during the
isotopy. The main tool used is a Mayer--Vietoris sequence for Lagrangian Floer
homology, obtained by "neck-stretching" and "splashing."


title: From expanded digraphs to lifts of voltage digraphs and line digraphs

abstract:
  In this note we present a general approach to construct large digraphs from
small ones. These are called expanded digraphs, and, as particular cases, we
show the close relationship between lifted digraphs of voltage digraphs and
line digraphs, which are two known ways to obtain dense digraphs. In the same
context, we show the equivalence between the vertex-splitting and partial line
digraph techniques. Then, we give a sufficient condition for a lifted digraph
of a base line digraph to be again a line digraph. Some of the results are
illustrated with two well-known families of digraphs. Namely, the De Bruijn and
Kautz digraphs, where it is shown that both families can be seen as lifts of
smaller De Bruijn digraphs with appropriate voltage assignments.


title:
Spatially Homogeneous Entanglement for Matter-Wave Interferometry
  Created with Time-Averaged Measurements

abstract:
  We demonstrate a method to generate spatially homogeneous entangled,
spin-squeezed states of atoms appropriate for maintaining a large amount of
squeezing even after release into the arm of a matter-wave interferometer or
other free space quantum sensor. Using an effective intracavity dipole trap, we
allow atoms to move along the cavity axis and time average their coupling to
the standing wave used to generate entanglement via collective measurements,
demonstrating 11(1) dB of directly observed spin squeezing. Our results show
that time averaging in collective measurements can greatly reduce the impact of
spatially inhomogeneous coupling to the measurement apparatus.


title:
Adaptive Probabilistic Trajectory Optimization via Efficient Approximate
  Inference

abstract:
  Robotic systems must be able to quickly and robustly make decisions when
operating in uncertain and dynamic environments. While Reinforcement Learning
(RL) can be used to compute optimal policies with little prior knowledge about
the environment, it suffers from slow convergence. An alternative approach is
Model Predictive Control (MPC), which optimizes policies quickly, but also
requires accurate models of the system dynamics and environment. In this paper
we propose a new approach, adaptive probabilistic trajectory optimization, that
combines the benefits of RL and MPC. Our method uses scalable approximate
inference to learn and updates probabilistic models in an online incremental
fashion while also computing optimal control policies via successive local
approximations. We present two variations of our algorithm based on the Sparse
Spectrum Gaussian Process (SSGP) model, and we test our algorithm on three
learning tasks, demonstrating the effectiveness and efficiency of our approach.


title: The homotopy type of the PL cobordism category. I

abstract:
  We introduce in this article a bordism category $\mathcal{C}_d^{PL}$ whose
objects are bundles of closed $(d-1)$-dimensional piecewise linear manifolds
and whose morphisms are bundles of $d$-dimensional piecewise linear cobordisms.
$\mathcal{C}_d^{PL}$ is a simplicial non-unital category and, in the main
theorem of this article, we show that its classifying space
$B\mathcal{C}_d^{PL}$ is weak homotopy equivalent to an infinite loop space. We
regard $\mathcal{C}_d^{PL}$ as the piecewise linear analogue of the category of
smooth cobordisms which has been studied extensively in connection to the
Madsen-Weiss Theorem, and the main result of this paper is a first step towards
obtaining Madsen-Weiss type results in the context of piecewise linear
topology.


title: Long-Baseline Neutrino Experiments

abstract:
  We review long-baseline neutrino experiments in which neutrinos are detected
after traversing macroscopic distances. Over such distances neutrinos have been
found to oscillate among flavor states. Experiments with solar, atmospheric,
reactor, and accelerator neutrinos have resulted in a coherent picture of
neutrino masses and mixing of the three known flavor states. We will summarize
the current best knowledge of neutrino parameters and phenomenology with our
focus on the evolution of the experimental technique. We proceed from the first
evidence produced by astrophysical neutrino sources to the current open
questions and the goals of future research.


title: Single-shot Adaptive Measurement for Quantum-enhanced Metrology

abstract:
  Quantum-enhanced metrology aims to estimate an unknown parameter such that
the precision scales better than the shot-noise bound. Single-shot adaptive
quantum-enhanced metrology (AQEM) is a promising approach that uses feedback to
tweak the quantum process according to previous measurement outcomes.
Techniques and formalism for the adaptive case are quite different from the
usual non-adaptive quantum metrology approach due to the causal relationship
between measurements and outcomes. We construct a formal framework for AQEM by
modeling the procedure as a decision-making process, and we derive the
imprecision and the Cram\'{e}r-Rao lower bound with explicit dependence on the
feedback policy. We also explain the reinforcement learning approach for
generating quantum control policies, which is adopted due to the optimal policy
being non-trivial to devise. Applying a learning algorithm based on
differential evolution enables us to attain imprecision for adaptive
interferometric phase estimation, which turns out to be SQL when non-entangled
particles are used in the scheme.


title:
Finite-temperature valence-bond-solid transitions and thermodynamic
  properties of interacting SU($2N$) Dirac fermions

abstract:
  We investigate the SU($2N$) symmetry effects with $2N>2$ on the
two-dimensional interacting Dirac fermions at finite temperatures, including
the valence-bond-solid transition, the Pomeranchuk effect, the compressibility
and the uniform spin susceptibility, by performing the determinant quantum
Monte Carlo simulations of the half-filled SU($2N$) Hubbard model on a
honeycomb lattice. The columnar valence-bond-solid (cVBS) phase only breaks the
three-fold discrete symmetry, and thus can survive at finite temperatures. The
disordered phase in the weak coupling regime is the thermal Dirac semi-metal
state, while in the strong coupling regime it is largely a Mott state in which
the cVBS order is thermally melted. The calculated entropy-temperature
relations for various values of the Hubbard interaction $U$ show that, the
Pomeranchuk effect occurs when the specific entropy is below a characteristic
value of $S^*$ --- the maximal entropy per particle from the spin channel of
local moments. The SU($2N$) symmetry enhances the Pomeranchuk effect, which
facilitates the interaction-induced adiabatic cooling. Our work sheds new light
on future explorations of novel states of matter with ultra-cold large-spin
alkaline fermions.


title: Detailed photometric analysis of young star groups in the galaxy NGC 300

abstract:
  The purpose of this work is to understand the global characteristics of the
stellar populations in NGC 300. In particular, we focused our attention on
searching young star groups and study their hierarchical organization.
  The research was conducted using archival point spread function fitting
photometry measured from images in multiple bands obtained with the Advanced
Camera for Surveys of the Hubble Space Telescope. Using the path linkage
criterion, we cataloged young star groups and analyzed them from the
observation of individual stars in the galaxy NGC 300. We also built stellar
density maps from the bluest stars and applied the SExtractor code to identify
overdensities. By plotting isocontours over the density maps and comparing the
two methods, we could infer and delineate the hierarchical structure of the
blue population in the galaxy. For each region of a detected young star group,
we estimated the size and derived the radial surface density profiles for
stellar populations of different color. A statistical decontamination of field
stars was performed for each region. In this way it was possible to build the
color-magnitude diagrams and compare them with theoretical evolutionary models.
We also constrained the present-day mass function per group by estimating a
value for its slope.
  The blue population in NGC 300 shows a hierarchical behavior in which the
larger and loosely distributed structures split into more compact and denser
ones over several density levels. We created a catalog of 1147 young star
groups in six fields of the galaxy NGC 300, in which we present their
fundamental characteristics. The mean and the mode radius values obtained from
the size distribution are both 25 pc, in agreement with the value for the Local
Group and nearby galaxies. Additionally, we found an average PDMF slope that is
compatible with the Salpeter value.


title: Modular Bootstrap Revisited

abstract:
  We constrain the spectrum of two-dimensional unitary, compact conformal field
theories with central charge c > 1 using modular bootstrap. Upper bounds on the
gap in the dimension of primary operators of any spin, as well as in the
dimension of scalar primaries, are computed numerically as functions of the
central charge using semi-definite programming. Our bounds refine those of
Hellerman and Friedan-Keller, and are in some cases saturated by known CFTs. In
particular, we show that unitary CFTs with c < 8 must admit relevant
deformations, and that a nontrivial bound on the gap of scalar primaries exists
for c < 25. We also study bounds on the dimension gap in the presence of twist
gaps, bounds on the degeneracy of operators, and demonstrate how "extremal
spectra" which maximize the degeneracy at the gap can be determined
numerically.


title: Some Models for Epidemics of Vector-Transmitted Diseases

abstract:
  Vector-transmitted diseases such as dengue fever and chikungunya have been
spreading rapidly in many parts of the world. The Zika virus has been known
since 1947 and invaded South America in 2013. It can be transmitted not only by
(mosquito) vectors but also directly through sexual contact. Zika has developed
into a serious global health problem because, while most cases are asymptomatic
or very light, babies born to Zika - infected mothers may develop microcephaly
and other very serious birth defects.
  We formulate and analyze two epidemic models for vector-transmitted diseases,
one appropriate for dengue and chikungunya fever outbreaks and one that
includes direct transmission appropriate for Zika virus outbreaks. This is
especially important because the Zika virus is the first example of a disease
that can be spread both indirectly through a vector and directly (through
sexual contact). In both cases, we obtain expressions for the basic
reproduction number and show how to use the initial exponential growth rate to
estimate the basic reproduction number. However, for the model that includes
direct transmission some additional data would be needed to identify the
fraction of cases transmitted directly. Data for the 2015 Zika virus outbreak
in Barranquilla, Colombia has been used to fit parameters to the model
developed here and to estimate the basic reproduction number.


title: TMCI threshold with space charge and different wake fields

abstract:
  Transverse mode coupling instability of a bunch with space charge and wake
field is considered within the frameworks of the boxcar model. Eigenfunctions
of the bunch without wake are used as a basis for the solution of the equations
with the wake field included. A dispersion equation for constant wake is
presented in the form of an infinite continued fraction and also as the
recursive relation with an arbitrary number of the basis functions. Realistic
wake fields are considered as well including resistive wall, square, and
oscillating wakes. It is shown that the TMCI threshold of the negative wake
grows up in absolute value when the SC tune shift increases. Threshold of
positive wake goes down at the increasing SC tune shift. The explanation is
developed by an analysis of the bunch spectrum.


title:
Analytical Investigations on Carrier Phase Recovery in
  Dispersion-Unmanaged n-PSK Coherent Optical Communication Systems

abstract:
  Using coherent optical detection and digital signal processing, laser phase
noise and equalization enhanced phase noise can be effectively mitigated using
the feed-forward and feed-back carrier phase recovery approaches. In this
paper, theoretical analyses of feed-back and feed-forward carrier phase
recovery methods have been carried out in the long-haul high-speed n-level
phase shift keying (n-PSK) optical fiber communication systems, involving a
one-tap normalized least-mean-square (LMS) algorithm, a block-wise average
algorithm, and a Viterbi-Viterbi algorithm. The analytical expressions for
evaluating the estimated carrier phase and for predicting the bit-error-rate
(BER) performance (such as the BER floors) have been presented and discussed in
the n-PSK coherent optical transmission systems by considering both the laser
phase noise and the equalization enhanced phase noise. The results indicate
that the Viterbi-Viterbi carrier phase recovery algorithm outperforms the
one-tap normalized LMS and the block-wise average algorithms for small phase
noise variance (or effective phase noise variance), while the one-tap
normalized LMS algorithm shows a better performance than the other two
algorithms for large phase noise variance (or effective phase noise variance).
In addition, the one-tap normalized LMS algorithm is more sensitive to the
level of modulation formats.


title:
The Remote Observatories of the Southeastern Association for Research in
  Astronomy (SARA)

abstract:
  We describe the remote facilities operated by the Southeastern Association
for Research in Astronomy (SARA), a consortium of colleges and universities in
the US partnered with Lowell Observatory, the Chilean National Telescope
Allocation Committee, and the Instituto de Astrofisica de Canarias. SARA
observatories comprise a 0.96m telescope at Kitt Peak, Arizona; a 0.6m
instrument on Cerro Tololo, Chile; and the 1m Jacobus Kapteyn Telescope at the
Roque de los Muchachos, La Palma, Spain. All are operated using standard VNC or
Radmin protocols communicating with on-site PCs. Remote operation offers
considerable flexibility in scheduling, allowing long-term observational
cadences difficult to achieve with classical observing at remote facilities, as
well as obvious travel savings. Multiple observers at different locations can
share a telescope for training, educational use, or collaborative research
programs. Each telescope has a CCD system for optical imaging, using
thermoelectric cooling to avoid the need for frequent local service, and a
second CCD for offset guiding. The Arizona and Chile instruments also have
fiber-fed echelle spectrographs. Switching between imaging and spectroscopy is
very rapid, so a night can easily accommodate mixed observing modes. We present
some sample observational programs. For the benefit of other groups organizing
similar consortia, we describe the operating structure and principles of SARA,
as well as some lessons learned from almost 20 years of remote operations.


title:
Callan-Giddings-Harvey-Strominger vacuum in loop quantum gravity and
  singularity resolution

abstract:
  We study here a complete quantization of a Callan-Giddings-Harvey-Strominger
(CGHS) vacuum model following loop quantum gravity techniques. Concretely, we
adopt a formulation of the model in terms of a set of new variables that
resemble the ones commonly employed in spherically symmetric loop quantum
gravity. The classical theory consists of two pairs of canonical variables plus
a scalar and diffeomorphism (first class) constraints. We consider a suitable
redefinition of the Hamiltonian constraint such that the new constraint algebra
(with structure constants) is well adapted to the Dirac quantization approach.
For it, we adopt a polymeric representation for both the geometry and the
dilaton field. On the one hand, we find a suitable invariant domain of the
scalar constraint operator, and we construct explicitly its solution space.
There, the eigenvalues of the dilaton and the metric operators cannot vanish
locally, allowing us to conclude that singular geometries are ruled out in the
quantum theory. On the other hand, the physical Hilbert space is constructed
out of them, after group averaging the previous states with the diffeomorphism
constraint. In turn, we identify the standard observable corresponding to the
mass of the black hole at the boundary, in agreement with the classical theory.
We also construct an additional observable on the bulk associated with the
square of the dilaton field, with no direct classical analog.


title: Mechanisms for Network Growth that Preserve Spectral and Local Structure

abstract:
  We introduce a method that can be used to evolve the topology of a network in
a way that preserves both the network's spectral as well as local structure.
This method is quite versatile in the sense that it can be used to evolve a
network's topology over any collection of the network's elements. This
evolution preserves both the eigenvector centrality of these elements as well
as the eigenvalues of the original network. Although this method is introduced
as a tool to model network growth, we show it can also be used to compare the
topology of different networks where two networks are considered similar if
their evolved topologies are the same. Because this method preserves the
spectral structure of a network, which is related to the network's dynamics, it
can also be used to study the interplay of network growth and function. We show
that if a network's dynamics is intrinsically stable, which is a stronger
version of the standard notion of stability, then the network remains
intrinsically stable as the network's topology evolves. This is of interest
since the growth of a network can have a destabilizing effect on the network's
dynamics, in general. In this sense the methods developed here can be used as a
tool for designing mechanisms of network growth that ensure a network remains
stabile as it grows.


title:
Visual C++ Implementation of Sinogram-based Adaptive Iterative
  Reconstruction for Sparse View X-Ray CT

abstract:
  With the availability of more powerful computing processors, iterative
reconstruction algorithms have recently been successfully implemented as an
approach to achieving significant dose reduction in X-ray CT. In this report,
we describe our proposal of an adaptive iterative reconstruction algorithm for
X-ray CT, that is shown to provide results comparable to those obtained by
proprietary algorithms, both in terms of reconstruction accuracy and execution
time. Implementation code in the C language is provided, along with example of
user interface.


title: A Survey on Honeypot Software and Data Analysis

abstract:
  In this survey, we give an extensive overview on honeypots. This includes not
only honeypot software but also methodologies to analyse honeypot data.


title: A class of $2$-local finite spectra which admit a $v_2^1$-self-map

abstract:
  At the prime $2$, Behrens, Hill, Hopkins and Mahowald showed $M_2(1,4)$
admits $32$-periodic $v_2$-self-map and more recently authors joint with
Mahowald showed $A_1$ also admits $32$-periodic $v_2$-self-map. This leads to
the question, whether there exists a finite $2$-local complex with periodicity
less than $32$. This paper will answer the question by producing a class of
finite $2$-local spectra $\widetilde{\mathcal{Z}}$ all of which admit
$1$-periodic $v_2$-self-map.


title: The phase space analysis of modified gravity (MOG)

abstract:
  We investigate the cosmological consequences of a scalar-vector-tensor theory
of gravity known as MOG. In MOG, in addition to metric tensor, there are two
scalar fields $G(x)$ and $\mu(x)$, and one vector field $\phi_{\alpha}(x)$.
Using the phase space analysis, we explore the cosmological consequences of a
model of MOG and find some new interesting features which are absent in
$\Lambda$CDM model. More specifically we study the possibility that if the
extra fields of this theory behave like dark energy to explain the cosmic
speedup. More interestingly, with or without cosmological constant, strongly
phantom crossing happens. Also we find that this theory in its original form
($\Lambda\neq 0$), possesses a true sequence of cosmological epochs. Albeit we
show that, surprisingly, there are two radiation dominated epochs $f_5$ and
$f_6$, two matter dominated phases $f_3$ and $f_4$, and two late time
accelerated eras $f_{12}$ and $f_{7}$. Depending on the initial conditions the
universe will realize only three of these six eras. However, the matter
dominated phases are dramatically different from the standard matter dominated
epoch. In these phases the cosmic scale factor grows as $a(t)\sim t^{0.46}$ and
$t^{0.52}$, respectively, which are slower than the standard case, i.e.
$a(t)\sim t^{2/3}$. Considering these results we discuss the cosmological
viability of MOG.


title: Holographic Renormalization of Einstein-Maxwell-Dilaton Theories

abstract:
  We generalize the boundary value problem with a mixed boundary condition that
involves the gauge and scalar fields in the context of Einstein-Maxwell-Dilaton
theories. In particular, the expectation value of the dual scalar operator can
be a function of the expectation value of the current operator. The properties
are prevalent in a fixed charge ensemble because the conserved charge is shared
by both fields through the dilaton coupling, which is also responsible for
non-Fermi liquid properties. We study the on-shell action and the stress energy
tensor to note practical importances of the boundary value problem. In the
presence of the scalar fields, physical quantities are not fully fixed due to
the finite boundary terms that manifest in the massless scalar or the scalar
with mass saturating the Breitenlohner-Freedman bound.


title: Multi-Dueling Bandits and Their Application to Online Ranker Evaluation

abstract:
  New ranking algorithms are continually being developed and refined,
necessitating the development of efficient methods for evaluating these
rankers. Online ranker evaluation focuses on the challenge of efficiently
determining, from implicit user feedback, which ranker out of a finite set of
rankers is the best. Online ranker evaluation can be modeled by dueling ban-
dits, a mathematical model for online learning under limited feedback from
pairwise comparisons. Comparisons of pairs of rankers is performed by
interleaving their result sets and examining which documents users click on.
The dueling bandits model addresses the key issue of which pair of rankers to
compare at each iteration, thereby providing a solution to the
exploration-exploitation trade-off. Recently, methods for simultaneously
comparing more than two rankers have been developed. However, the question of
which rankers to compare at each iteration was left open. We address this
question by proposing a generalization of the dueling bandits model that uses
simultaneous comparisons of an unrestricted number of rankers. We evaluate our
algorithm on synthetic data and several standard large-scale online ranker
evaluation datasets. Our experimental results show that the algorithm yields
orders of magnitude improvement in performance compared to stateof- the-art
dueling bandit algorithms.


title:
Automated Synthesis of Semantic Malware Signatures using Maximum
  Satisfiability

abstract:
  This paper proposes a technique for automatically learning semantic malware
signatures for Android from very few samples of a malware family. The key idea
underlying our technique is to look for a maximally suspicious common subgraph
(MSCS) that is shared between all known instances of a malware family. An MSCS
describes the shared functionality between multiple Android applications in
terms of inter-component call relations and their semantic metadata (e.g.,
data-flow properties). Our approach identifies such maximally suspicious common
subgraphs by reducing the problem to maximum satisfiability. Once a semantic
signature is learned, our approach uses a combination of static analysis and a
new approximate signature matching algorithm to determine whether an Android
application matches the semantic signature characterizing a given malware
family.
  We have implemented our approach in a tool called ASTROID and show that it
has a number of advantages over state-of-the-art malware detection techniques.
First, we compare the semantic malware signatures automatically synthesized by
ASTROID with manually-written signatures used in previous work and show that
the signatures learned by ASTROID perform better in terms of accuracy as well
as precision. Second, we compare ASTROID against two state-of-the-art malware
detection tools and demonstrate its advantages in terms of interpretability and
accuracy. Finally, we demonstrate that ASTROID's approximate signature matching
algorithm is resistant to behavioral obfuscation and that it can be used to
detect zero-day malware. In particular, we were able to find 22 instances of
zero-day malware in Google Play that are not reported as malware by existing
tools.


title: The $\mathbb{Z}_2$-orbifold of the $\mathcal{W}_3$-algebra

abstract:
  The Zamolodchikov $\mathcal{W}_3$-algebra $\mathcal{W}^c_3$ with central
charge $c$ has full automorphism group $\mathbb{Z}_2$. It was conjectured in
the physics literature over 20 years ago that the orbifold
$(\mathcal{W}^c_3)^{\mathbb{Z}_2}$ is of type $\mathcal{W}(2,6,8,10,12)$ for
generic values of $c$. We prove this conjecture for all $c \neq \frac{559 \pm 7
\sqrt{76657}}{95}$, and we show that for these two values, the orbifold is of
type $\mathcal{W}(2,6,8,10,12,14)$. This paper is part of a larger program of
studying orbifolds and cosets of vertex algebras that depend continuously on a
parameter. Minimal strong generating sets for orbifolds and cosets are often
easy to find for generic values of the parameter, but determining which values
are generic is a difficult problem. In the example of
$(\mathcal{W}^c_3)^{\mathbb{Z}_2}$, we solve this problem using tools from
algebraic geometry.


title: On the $K$-sat model with large number of clauses

abstract:
  We show that in the $K$-sat model with $N$ variables and $\alpha N$ clauses,
the expected ratio of the smallest number of unsatisfied clauses to the number
of variables is $\alpha/2^K - \sqrt{\alpha} c_*(N)/2^K$ up to smaller order
terms $o(\sqrt{\alpha})$ as $\alpha\to\infty$ uniformly in $N$, where $c_*(N)$
is the expected normalized maximum energy of some specific mixed $p$-spin spin
glass model. The formula for the limit of $c_*(N)$ is well known in the theory
of spin glasses.


title: Reduction of wind power variability through geographic diversity

abstract:
  The variability of wind-generated electricity can be reduced by aggregating
the outputs of wind generation plants spread over a large geographic area. In
this chapter we utilize Monte Carlo simulations to investigate upper bounds on
the degree of achievable smoothing and clarify how the degree of smoothing
depends on the number of plants and on the size of the geographic area over
which they are spread.


title:
Large Observatory for x-ray Timing (LOFT-P): A Probe-classs Mission
  Concept Study

abstract:
  LOFT-P is a concept for a NASA Astrophysics Probe-Class (<$1B) X-ray timing
mission, based on the LOFT concept originally proposed to ESAs M3 and M4 calls.
LOFT-P requires very large collecting area (>6 m^2, >10x RXTE), high time
resolution, good spectral resolution, broad-band spectral coverage (2-30 keV),
highly flexible scheduling, and an ability to detect and respond promptly to
time-critical targets of opportunity. It addresses science questions such as:
What is the equation of state of ultra dense matter? What are the effects of
strong gravity on matter spiraling into black holes? It would be optimized for
sub-millisecond timing to study phenomena at the natural timescales of neutron
star surfaces and black hole event horizons and to measure mass and spin of
black holes. These measurements are synergistic to imaging and high-resolution
spectroscopy instruments, addressing much smaller distance scales than are
possible without very long baseline X-ray interferometry, and using
complementary techniques to address the geometry and dynamics of emission
regions. A sky monitor (2-50 keV) acts as a trigger for pointed observations,
providing high duty cycle, high time resolution monitoring of the X-ray sky
with ~20 times the sensitivity of the RXTE All-Sky Monitor, enabling
multi-wavelength and multi-messenger studies. A probe-class mission concept
would employ lightweight collimator technology and large-area solid-state
detectors, technologies which have been recently greatly advanced during the
ESA M3 study. Given the large community interested in LOFT (>800 supporters,
the scientific productivity of this mission is expected to be very high,
similar to or greater than RXTE (~2000 refereed publications). We describe the
results of a study, recently completed by the MSFC Advanced Concepts Office,
that demonstrates that LOFT-P is feasible within a NASA probe-class mission
budget.


title:
Linear and nonlinear instabilities of a granular bed: determination of
  the scales of ripples and dunes in rivers

abstract:
  Granular media are frequently found in nature and in industry and their
transport by a fluid flow is of great importance to human activities. One case
of particular interest is the transport of sand in open-channel and river
flows. In many instances, the shear stresses exerted by the fluid flow are
bounded to certain limits and some grains are entrained as bed-load: a mobile
layer which stays in contact with the fixed part of the granular bed. Under
these conditions, an initially flat granular bed may be unstable, generating
ripples and dunes such as those observed on the bed of rivers. In free-surface
water flows, dunes are bedforms that scale with the flow depth, while ripples
do not scale with it. This article presents a model for the formation of
ripples and dunes based on the proposition that ripples are primary linear
instabilities and that dunes are secondary instabilities formed from the
competition between the coalescence of ripples and free surface effects.
Although simple, the model is able to explain the growth of ripples, their
saturation (not explained in previous models) and the evolution from ripples to
dunes, presenting a complete picture for the formation of dunes.


title:
Magnetic-field-induced abrupt spin state transition in a quantum dot
  containing magnetic ions

abstract:
  We present the results of a comprehensive magneto-optical characterization of
single CdTe quantum dots containing a few Mn2+ ions. We find that some quantum
dots exhibit an unexpected evolution of excitonic photoluminescence spectrum
with the magnetic field. At a certain value of the magnetic field, specific for
every quantum dot, each of the broad spectral lines related to the
recombination of various excitonic complexes confined inside the dot transforms
into a pair of narrow lines split by several meV. We interpret this abrupt
change in the character of excitonic emission spectrum as a consequence of a
transition from a non-polarized state of the Mn2+ spins in a low field regime
to a highly (almost fully) polarized state above the critical magnetic field.
Various optical experiments, including polarization-resolved studies,
investigation of different excitation regimes and time-resolved measurements
corroborate this scenario. However, these measurements indicate also that the
observed effect is not related or influenced by the photo-created charge
carriers, but it is rather originating from unusual spin configuration in the
cluster of Mn2+ ions.


title:
Spectral analysis of four 'hypervariable' AGN: a microneedle in the
  haystack?

abstract:
  We analyze four extreme active galactic nuclei (AGN) transients to explore
the possibility that they are caused by rare, high-amplitude microlensing
events. These previously unknown type-I AGN are located in the redshift range
0.6-1.1 and show changes of > 1.5 mag in the g-band on a time-scale of ~years.
Multi-epoch optical spectroscopy, from the William Herschel Telescope, shows
clear differential variability in the broad line fluxes with respect to the
continuum changes and also evolution in the line profiles. In two cases, a
simple point-source, point-lens microlensing model provides an excellent match
to the long-term variability seen in these objects. For both models, the
parameter constraints are consistent with the microlensing being due to an
intervening stellar mass object but as yet there is no confirmation of the
presence of an intervening galaxy. The models predict a peak amplification of
10.3/13.5 and an Einstein time-scale of 7.5/10.8 yr, respectively. In one case,
the data also allow constraints on the size of the CIII] emitting region, with
some simplifying assumptions, to to be ~1.0-6.5 light-days and a lower limit on
the size of the MgII emitting region to be > 9 light-days (half-light radii).
This CIII] radius is perhaps surprisingly small. In the remaining two objects,
there is spectroscopic evidence for an intervening absorber but the extra
structure seen in the light curves requires a more complex lensing scenario to
adequately explain.


title:
ICE: a scalable, low-cost FPGA-based telescope signal processing and
  networking system

abstract:
  We present an overview of the 'ICE' hardware and software framework that
implements large arrays of interconnected FPGA-based data acquisition, signal
processing and networking nodes economically. The system was conceived for
application to radio, millimeter and sub-millimeter telescope readout systems
that have requirements beyond typical off-the-shelf processing systems, such as
careful control of interference signals produced by the digital electronics,
and clocking of all elements in the system from a single precise
observatory-derived oscillator. A new generation of telescopes operating at
these frequency bands and designed with a vastly increased emphasis on digital
signal processing to support their detector multiplexing technology or
high-bandwidth correlators---data rates exceeding a terabyte per second---are
becoming common. The ICE system is built around a custom FPGA motherboard that
makes use of an Xilinx Kintex-7 FPGA and ARM-based co-processor. The system is
specialized for specific applications through software, firmware, and custom
mezzanine daughter boards that interface to the FPGA through the
industry-standard FMC specifications. For high density applications, the
motherboards are packaged in 16-slot crates with ICE backplanes that implement
a low-cost passive full-mesh network between the motherboards in a crate, allow
high bandwidth interconnection between crates, and enable data offload to a
computer cluster. A Python-based control software library automatically detects
and operates the hardware in the array. Examples of specific telescope
applications of the ICE framework are presented, namely the
frequency-multiplexed bolometer readout systems used for the SPT and Simons
Array and the digitizer, F-engine, and networking engine for the CHIME and
HIRAX radio interferometers.


title: Detection of the secondary eclipse of Qatar-1b in the Ks band

abstract:
  Qatar-1b is a close-orbiting hot Jupiter ($R_p\simeq 1.18$ $R_J$, $M_p\simeq
1.33$ $M_J$) around a metal-rich K-dwarf, with orbital separation and period of
0.023 AU and 1.42 days. We have observed the secondary eclipse of this
exoplanet in the Ks band with the objective of deriving a brightness
temperature for the planet and providing further constraints to the orbital
configuration of the system. We obtained near-infrared photometric data from
the ground by using the OMEGA2000 instrument at the 3.5 m telescope at Calar
Alto (Spain) in staring mode, with the telescope defocused. We have used
principal component analysis (PCA) to identify correlated systematic trends in
the data. A Markov chain Monte Carlo analysis was performed to model the
correlated systematics and fit for the secondary eclipse of Qatar-1b using a
previously developed occultation model. We adopted the prayer bead method to
assess the effect of red noise on the derived parameters. We measured a
secondary eclipse depth of $0.196\%^{+0.071\%}_{-0.051\%}$, which indicates a
brightness temperature in the Ks band for the planet of $1885^{+212}_{-168}$ K.
We also measured a small deviation in the central phase of the secondary
eclipse of $-0.0079^{+0.0162}_{-0.0043}$, which leads to a value for
$e\cos{\omega}$ of $-0.0123^{+0.0252}_{-0.0067}$. However, this last result
needs to be confirmed with more data.


title: Low-mass disc galaxies and the issue of stability: MOND vs dark matter

abstract:
  We analyse the rotation curves and gravitational stability of a sample of six
bulgeless galaxies for which detailed images reveal no evidence for strong
bars. We explore two scenarios: Newtonian dark matter models and MOdified
Newtonian Dynamics (MOND). By adjusting the stellar mass-to-light ratio, dark
matter models can match simultaneously both the rotation curve and
bar-stability requirements in these galaxies. To be consistent with stability
constraints, in two of these galaxies, the stellar mass-to-light ratio is a
factor of ~1.5-2 lower than the values suggested from galaxy colours. In
contrast, MOND fits to the rotation curves are poor in three galaxies, perhaps
because the gas tracer contains noncircular motions. The bar stability analysis
provides a new observational test to MOND. We find that most of the galaxies
under study require abnormally-high levels of random stellar motions to be bar
stable in MOND. In particular, for the only galaxy in the sample for which the
line-of-sight stellar velocity dispersion has been measured (NGC 6503), the
observed velocity dispersion is not consistent with MOND predictions because it
is far below the required value to guarantee bar stability. Precise
measurements of mass-weighted velocity dispersions in (unbarred and bulgeless)
spiral galaxies are crucial to test the consistency of MOND.


title:
On the linearity of lattices in affine buildings and ergodicity of the
  singular Cartan flow

abstract:
  Let $X$ be a locally finite irreducible affine building of dimension $\geq 2$
and $\Gamma \leq \mathrm{Aut}(X)$ be a discrete group acting cocompactly. The
goal of this paper is to address the following question: When is $\Gamma$
linear? More generally, when does $\Gamma$ admit a finite-dimensional
representation with infinite image over a commutative unital ring? If $X$ is
the Bruhat--Tits building of a simple algebraic group over a local field and if
$\Gamma$ is an arithmetic lattice, then $\Gamma$ is clearly linear. We prove
that if $X$ is of type $\widetilde A_2$, then the converse holds. In
particular, cocompact lattices in exotic $\widetilde A_2$-buildings are
non-linear. As an application, we obtain the first infinite family of lattices
in exotic $\widetilde A_2$-buildings of arbitrarily large thickness, providing
also a partial answer to a question of W. Kantor from 1986. We also show that
if $X$ is Bruhat--Tits of arbitrary type, then the linearity of $\Gamma$
implies that $\Gamma$ is virtually contained in the linear part of the
automorphism group of $X$, in particular $\Gamma$ is an arithmetic lattice. The
proofs are based on the machinery of algebraic representations of ergodic
systems recently developed by U. Bader and A. Furman. The implementation of
that tool in the present context requires the geometric construction of a
suitable ergodic $\Gamma$-space attached to the the building $X$, which we call
the \emph{singular Cartan flow}.


title: Naturally Stable Right-Handed Neutrino Dark Matter

abstract:
  We point out that a class of non-supersymmetric models based on the gauge
group $SU(3)_C \times SU(2)_L\times SU(2)_R\times U(1)_{Y_L}\times U(1)_{Y_R}$
possesses an automatic, exact $Z_{2 }$ symmetry under which the fermions in the
$SU(2)_R\times U(1)_{Y_R}$ sector (called $R$-sector) are odd and those in the
standard model sector (called $L$-sector) are even. This symmetry, which is
different from the usual parity symmetry of the left-right symmetric models,
persists in the lepton sector even after the gauge symmetry breaks down to
$SU(3)_C \times U(1)_{\rm EM}$. This keeps the lightest right-handed neutrino
naturally stable, thereby allowing it to play the role of dark matter (DM) in
the Universe. There are several differences between the usual left-right models
and the model presented here: (i) our model can have two versions, one which
has no parity symmetry so that the couplings and masses in the $L$ and $R$
sectors are unrelated, and another which has parity symmetry so that couplings
are related; (ii) the $R$-sector fermions are chosen much heavier than the
$L$-sector ones in both scenarios; and finally (iii) both light and heavy
neutrinos are Majorana fermions with the light neutrino masses arising from a
pure type-II seesaw mechanism. We discuss the DM relic density, direct and
indirect detection prospects and associated collider signatures of the model.
Comparing with current collider and direct detection constraints, we find a
lower bound on the DM mass of order of 1 TeV. We also point out a way to relax
the DM unitarity bound in our model for much larger DM masses by an entropy
dilution mechanism. An additional feature of the model is that the DM can be
made very long lived, if desired, by allowing for weak breaking of the above
$Z_{2}$ symmetry. Our model also predicts the existence of long-lived colored
particles which could be searched for at the LHC.


title: Dark matter and the neutrino portal paradigm

abstract:
  A simple extension of the Standard Model (SM) that provides an explicit
realization of the dark-matter (DM) neutrino-portal paradigm is presented. The
leading interactions between the dark sector, containing scalars and relic
fermions, and the SM involve neutrinos. This model meets all observational
constraints.


title:
Doping Evolution of Magnetic Order and Magnetic Excitations in
  (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$

abstract:
  We use resonant elastic and inelastic X-ray scattering at the Ir-$L_3$ edge
to study the doping-dependent magnetic order, magnetic excitations and
spin-orbit excitons in the electron-doped bilayer iridate
(Sr$_{1-x}$La$_{x}$)$_3$Ir$_2$O$_7$ ($0 \leq x \leq 0.065$). With increasing
doping $x$, the three-dimensional long range antiferromagnetic order is
gradually suppressed and evolves into a three-dimensional short range order
from $x = 0$ to $0.05$, followed by a transition to two-dimensional short range
order between $x = 0.05$ and $0.065$. Following the evolution of the
antiferromagnetic order, the magnetic excitations undergo damping, anisotropic
softening and gap collapse, accompanied by weakly doping-dependent spin-orbit
excitons. Therefore, we conclude that electron doping suppresses the magnetic
anisotropy and interlayer couplings and drives
(Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$ into a correlated metallic state hosting
two-dimensional short range antiferromagnetic order and strong
antiferromagnetic fluctuations of $J_{\text{eff}} = \frac{1}{2}$ moments, with
the magnon gap strongly suppressed.


title: On generic and dense chaos for maps induced on hyperspaces

abstract:
  A continuous map $f$ on a compact metric space $X$ induces in a natural way
the map $\tilde f$ on the hyperspace $\mathcal K(X)$ of all closed non-empty
subsets of $X$. We study the question of transmission of chaos between $f$ and
$\tilde f$. We deal with generic, generic $\varepsilon$-, dense and dense
$\varepsilon$-chaos for interval maps. We prove that all four types of chaos
transmit from $f$ to $\tilde f$, while the converse transmission from $\tilde
f$ to $f$ is true for generic, generic $\varepsilon$- and dense
$\varepsilon$-chaos. Moreover, the transmission of dense $\varepsilon$- and
generic $\varepsilon$-chaos from $\tilde f$ to $f$ is true for maps on general
compact metric spaces.


title: On Asymptotic Expansions in Spin Boson Models

abstract:
  We consider expansions of eigenvalues and eigenvectors of models of quantum
field theory. For a class of models known as generalized spin boson model we
prove the existence of asymptotic expansions of the ground state and the ground
state energy to arbitrary order. We need a mild but very natural infrared
assumption, which is weaker than the assumption usually needed for other
methods such as operator theoretic renormalization to be applicable. The result
complements previously shown analyticity properties.


title: Black hole at Lovelock gravity with anisotropic fluid

abstract:
  In this work a new family of black hole solutions in Lovelock gravity is
discussed. These solutions describe anisotropic fluids which extend to the
spatial infinity. Though far from the horizon their geometries approach some
previously known black holes solutions the location of the horizons differ.
Furthemore, although the masses of these solutions match the masses of those
previously known black holes, their temperatures and entropies differ.


title:
ASIC Design of a Noisy Gradient Descent Bit Flip Decoder for 10GBASE-T
  Ethernet Standard

abstract:
  In this paper, the NGDBF algorithm is implemented on a code that is deployed
in the IEEE 802.3an Ethernet standard. The design employs a fully parallel
architecture and operates in two-phases: start-up phase and decoding phase. The
two phase operation keeps the high latency operations off-line, thereby
reducing the decoding latency during the decoding phase. The design is
bench-marked with other state-of-the-art designs on the same code that employ
different algorithms and architectures. The results indicate that the NGDBF
decoder has a better area efficiency and a better energy efficiency compared to
other state-of-art decoders. When the design is operated in medium to high
signal to noise ratios, the design is able to provide greater than the required
minimum throughput of 10Gbps. The design consumes 0.81mm2 of area and has an
energy efficiency of 1.7pJ/bit, which are the lowest in the reported
literature. The design also provides better error performance compared to other
simplified decoder implementations and consumes lesser wire-length compared to
a recently proposed design.


title:
Optimization of infrared and magnetic shielding of superconducting TiN
  and Al coplanar microwave resonators

abstract:
  We present a systematic study of the effects of shielding on the internal
quality factors (Qi) of Al and TiN microwave resonators designed for use in
quantum coherent circuits. Measurements were performed in an adiabatic
demagnetization refrigerator, where typical magnetic fields of 200 {\mu}T are
present at the unshielded sample stage. Radiation shielding consisted of 100 mK
and 500 mK Cu cans coated with infrared absorbing epoxy. Magnetic shields
consisted of Cryoperm 10 and Sn plating of the Cu cans. A 2.7 K radiation can
and coaxial thermalization filters were present in all measurements. TiN
samples with Qi = $1.3*10^6$ at 100 mK exhibited no significant variation in
quality factor when tested with limited shielding. In contrast, Al resonators
showed improved Qi with successive shielding, with the largest gains obtained
from the addition of the first radiation and magnetic shields and saturating
before the addition of Sn plating infrared absorbing epoxy.


title: Homological combinatorics and extensions of the cd-index

abstract:
  Many combinatorial proofs rely on induction. When these proofs are formulated
in traditional language, they can be bulky and unmanageable. Coalgebras provide
a language which can reduce reduce many inductive proofs in graded poset theory
to comprehensible size. As a bonus, the visual form of the resulting recursive
proofs suggests combinatorial interpretations for constants appearing in the
longer arguments. We use the techniques of coalgebras to compute invariants of
toric and affine arrangements as well as of poset products. In additional
chapters we prove structure theorems for acyclic orientations and critical
groups of graphs.


title:
Superconducting Order from Disorder in 2H-TaSe$_{2-x}$S$_{x}$
  (0$\leq$x$\leq$2)

abstract:
  We report on the emergence of robust superconducting order in single crystal
alloys of 2H-TaSe$_{2-x}$S$_{x}$ (0$\leq$x$\leq$2) . The critical temperature
of the alloy is surprisingly higher than that of the two end compounds
TaSe$_{2}$ and TaS$_{2}$. The evolution of superconducting critical temperature
T$_{c} (x)$ correlates with the full width at half maximum of the Bragg peaks
and with the linear term of the high temperature resistivity. The conductivity
of the crystals near the middle of the alloy series is higher or similar than
that of either one of the end members 2H-TaSe$_{2}$ and/or 2H-TaS$_{2}$. It is
known that in these materials superconductivity (SC) is in close competition
with charge density wave (CDW) order. We interpret our experimental findings in
a picture where disorder tilts this balance in favor of superconductivity by
destroying the CDW order.


title: Coloring the Real Line with Monochromatic Intervals

abstract:
  Let D be a finite set of positive real numbers. The distance graph G(R,D) is
the graph with vertex set R (set of real numbers), and two vertices x, y are
adjacent if |x-y| belongs to D. We prove that every positive integer t>1 there
is a distance set D such that the chromatic number of G(R,D) is t and no proper
coloring of G(R,D) with t colors allows monochromatic intervals. This result
disproves a conjecture in [2].


title:
Fundamental principles of cortical computation: unsupervised learning
  with prediction, compression and feedback

abstract:
  There has been great progress in understanding of anatomical and functional
microcircuitry of the primate cortex. However, the fundamental principles of
cortical computation - the principles that allow the visual cortex to bind
retinal spikes into representations of objects, scenes and scenarios - have so
far remained elusive. In an attempt to come closer to understanding the
fundamental principles of cortical computation, here we present a functional,
phenomenological model of the primate visual cortex. The core part of the model
describes four hierarchical cortical areas with feedforward, lateral, and
recurrent connections. The three main principles implemented in the model are
information compression, unsupervised learning by prediction, and use of
lateral and top-down context. We show that the model reproduces key aspects of
the primate ventral stream of visual processing including Simple and Complex
cells in V1, increasingly complicated feature encoding, and increased
separability of object representations in higher cortical areas. The model
learns representations of the visual environment that allow for accurate
classification and state-of-the-art visual tracking performance on novel
objects.


title:
Light yield of an undoped CsI crystal coupled directly to a
  photomultiplier tube at 77 Kelvin

abstract:
  A light yield of 20.4 $\pm$ 0.8 photoelectrons/keV was achieved with an
undoped CsI crystal coupled directly to a photomultiplier tube at 77 Kelvin.
This is by far the largest yield in the world achieved with CsI crystals. An
energy threshold that is several times lower than the current dark matter
experiments utilizing CsI(Tl) crystals may be achievable using this technique.
Together with novel CsI crystal purification methods, the technique may be used
to improve the sensitivities of dark matter and coherent elastic
neutrino-nucleus scattering experiments. Also measured were the scintillation
light decay constants of the undoped CsI crystal at both room temperature and
77 Kelvin. The results are consistent with those in the literature.


title: A tight estimate for the waist of the ball

abstract: We answer a question of M. Gromov on the waist of the unit ball.


title: Path Integral Solutions to the Distributions of Statistical Mechanics

abstract:
  We present the path-integral solutions to the distributions in classical
(Gibbs) and quantum (Wigner) statistical mechanics. The kernel of the
distributions are derived in two ways - one by time slicing and defining the
appropriate short-time interval phase space matrix element and second by making
use of the kernel in the path-integral approach to quantum mechanics. We show
that the two approaches are perturbatively identical. We also present another
computation for the Wigner kernel, which is also the Liouville kernel, for the
harmonic oscillator and free particle. These kernels may be used as the
starting point in the perturbative expansion of the Wigner kernel for any
potential. With the kernel solved, we essentially solve also the distributions
in classical and quantum statistical mechanics.