title:
Non-perturbative Gauge-Higgs Unification, a quantum and bosonic
  mechanism of spontaneous gauge symmetry breaking

abstract:
  We review a construction called Non-Perturbative Gauge-Higgs Unification
which is a rather rare type of Higgs mechanism that is a pure quantum and
bosonic effect. It is constructed on a five-dimensional "orbifold lattice" with
SU(2) bulk gauge symmetry and a (spontaneously broken) Abelian-Higgs like
theory on the boundaries.


title:
Stability of the d-wave pairing with respect to the intersite Coulomb
  repulsion in cuprate superconductors

abstract:
  Within the spin-fermion model for cuprate superconductors, the influence of
the intersite Coulomb interactions $V_2$ and $V_2'$ between holes located at
the next-nearest-neighbor oxygen ions of CuO$_2$ plane on the implementation of
the d_{x^2-y^2}-wave pairing is studied. It is shown that d-wave pairing can be
suppressed only for unphysically large values of $V_2$ and $V_2'$.


title: Bounds on Codes with Locality and Availability

abstract:
  In this paper we investigate bounds on rate and minimum distance of codes
with $t$ availability. We present bounds on minimum distance of a code with $t$
availability that are tighter than existing bounds. For bounds on rate of a
code with $t$ availability, we restrict ourselves to a sub-class of codes with
$t$ availability called codes with strict $t$ availability and derive a tighter
rate bound. Codes with strict $t$ availability can be defined as the null space
of an $(m \times n)$ parity-check matrix $H$, where each row has weight $(r+1)$
and each column has weight $t$, with intersection between support of any two
rows atmost one. We also present two general constructions for codes with $t$
availability.


title:
Boundary conditions and heat resistance at the moving solid--liquid
  interface

abstract:
  Boundary conditions for the solid-liquid interface of the solidifying pure
melt have been derived. In the derivation the model of Gibbs interface is used.
The boundary conditions include both the state quantities of bulk phases are
taken at the interface and the quantities characterizing interfacial surface
such as the surface temperature and the surface heat flux. Introduction of the
surface temperature as an independent variable allows us to describe the
scattering energy at the interface. For the steady-state motion of the planar
interface the expression for the temperature discontinuity across the phase
boundary has been obtained. Effect of Kapitza resistance on the interface
velocity is considered. It is shown that heat resistance leads to non-linearity
in solidification kinetics, namely, in "velocity-undercooling" relationship.
The conditions of the steady--state motion of the planar interface has been
found.


title:
Ab Initio Modeling Of Friction Reducing Agents Shows Quantum Mechanical
  Interactions Can Have Macroscopic Manifestation

abstract:
  Two of the most commonly encountered friction reducing agents used in plastic
sheet production are the amides known as erucamide and behenamide, which
despite being almost identical chemically, lead to markedly different values of
the friction coefficient. To understand the origin of this contrasting
behavior, in this work we model brushes made of these two types of linear chain
molecules using quantum mechanical numerical simulations under the Density
Functional Theory at the B97D/6-31G(d,p)level of theory. Four chains of
erucamide and behenamide were linked to a 2X10 zigzag graphene sheet and
optimized both in vacuum and in continuous solvent using the SMD implicit
solvation model. We find that erucamide chains tend to remain closer together
through {\pi}{\pi} stacking interactions arising from the double bonds located
at C13 C14, a feature behenamide lacks and thus a more spread configuration is
obtained with the latter. It is argued that this arrangement of the erucamide
chains is responsible for the lower friction coefficient of erucamide brushes,
compared with behenamide brushes, which is a macroscopic consequence of
cooperative quantum mechanical interactions. While only quantum level
interactions are modeled here, we show that behenamide chains are more spread
out in the brush than erucamide chains as a consequence of those interactions.
The spread out configuration allows more solvent particles to penetrate the
brush, leading in turn to more friction, in agreement with macroscopic
measurements and mesoscale simulations of the friction coefficient reported in
the literature.


title: The Flow of Gauge Transformations on Riemannian Surface with Boundary

abstract:
  We consider the gauge transformations of a metric $G$-bundle over a compact
Riemannian surface with boundary. By employing the heat flow method, the local
existence and the long time existence of generalized solution are proved.


title: Neck Analysis of Extrinsic Polyharmonic Maps

abstract:
  We prove the energy identity and the no neck property for a sequence of
smooth extrinsic polyharmonic maps with bounded total energy.


title: Finite difference methods for fractional Laplacians

abstract:
  The fractional Laplacian $(-\Delta)^{\alpha/2}$ is the prototypical non-local
elliptic operator. While analytical theory has been advanced and understood for
some time, there remain many open problems in the numerical analysis of the
operator. In this article, we study several different finite difference
discretisations of the fractional Laplacian on uniform grids in one dimension
that takes the same form. Many properties can be compared and summarised in
this relatively simple setting, to tackle more important questions like the
nonlocality, singularity and flat tails common in practical implementations.
The accuracy and the asymptotic behaviours of the methods are also studied,
together with treatment of the far field boundary conditions, providing a
unified perspective on the further development of the scheme in higher
dimensions.


title:
Alpha-event and surface characterisation in segmented true-coaxial HPGe
  detectors

abstract:
  A detailed study of alpha interactions on the passivation layer on the
end-plate of a true-coaxial high-purity germanium detector is presented. The
observation of alpha events on such a surface indicates an unexpectedly thin
so-called "dead layer" of less than 20 {\mu}m thickness. In addition, the
influence of the metalisation close to the end-plate on the time evolution of
the output pulses is discussed. The results indicate that alpha contamination
can result in events which could be mistaken as signals for neutrinoless double
beta decay and provide some guidance on how to prevent this.


title:
Exploring detection of nuclearites in a large liquid scintillator
  neutrino detector

abstract:
  We take the JUNO experiment as an example to explore nuclearites in the
future large liquid scintillator detector. Comparing to the previous
calculations, the visible energy of nuclearites across the liquid scintillator
will be reestimated for the liquid scintillator based detector. Then the JUNO
sensitivities to the nuclearite flux are presented. It is found that the JUNO
projected sensitivities can be better than $7.7 \times 10^{-17} {\rm cm^{-2}
s^{-1} sr^{-1}}$ for the nuclearite mass $10^{15} \; {\rm GeV} \leq M \leq
10^{24}$ GeV and initial velocity $10^{-4} \leq \beta_0 \leq 10^{-1}$ with a 20
year running. Note that the JUNO will give the most stringent limits for
downgoing nuclearites with $1.6 \times 10^{13} \; {\rm GeV} \leq M \leq 4.0
\times 10^{15}$ GeV and a typical galactic velocity $\beta_0 = 10^{-3}$.


title: The structure of dust aggregates in hierarchical coagulation

abstract:
  Dust coagulation in interstellar space and protoplanetary disks is usually
treated as one of 2 extreme cases: Particle-Cluster Aggregation and
Cluster-Cluster Aggregation. In this paper we study the process of hierarchical
growth, where aggregates are built from significantly smaller aggregates (but
not monomers). We show that this process can be understood as a modified,
PCA-like process that produces porous, but non-fractal particles whose filling
factor is chiefly determined by the porosity of the building blocks.
  We also show that in a coagulation environment where relative velocities are
driven by turbulence, a logarithmically flat mass distribution (equal mass per
mass decade) as it is typically found in environments where fragmentation
replenishes small grains, leads to a situation where small particles and
aggregates dominate the growth of large ones. Therefore, in such environments,
hierarchical growth should be seen as the norm. Consequently, we predict that
the aggregates in such environments are not fractals with extremely low
densities as they would result from extrapolation fractal laws to large sizes.
The compactification of aggregates does not only result from collisions with
enough energy to restructure aggregates - it starts already earlier by filling
voids in particles with smaller grains that contribute to the growth.


title: A chiral covariant approach to $\rho\rho$ scattering

abstract:
  We analyze vector meson - vector meson scattering in a unitarized chiral
theory based on a chiral covariant framework. We show that a pole assigned to
the the scalar meson $f_0(1370)$ can be dynamically generated from the
$\rho\rho$ interaction, while this is not the case for the tensor meson
$f_2(1270)$ as found in earlier works. We show that the generation of the
tensor state is untenable due to an artefact of the extreme non-relativistic
kinematics used before. We further consider the effects arising from the
coupling of channels with different orbital angular momenta. We suggest to use
the formalism outlined here to obtain more reliable results for the dynamical
generation of resonances in the vector-vector interaction.


title: Multiuser Media-based Modulation for Massive MIMO Systems

abstract:
  In this paper, we consider {\em media-based modulation (MBM)}, an attractive
modulation scheme which is getting increased research attention recently, for
the uplink of a massive MIMO system. Each user is equipped with one transmit
antenna with multiple radio frequency (RF) mirrors (parasitic elements) placed
near it. The base station (BS) is equipped with tens to hundreds of receive
antennas. MBM with $m_{rf}$ RF mirrors and $n_r$ receive antennas over a
multipath channel has been shown to asymptotically (as $m_{rf}\rightarrow
\infty$) achieve the capacity of $n_r$ parallel AWGN channels. This suggests
that MBM can be attractive for use in massive MIMO systems which typically
employ a large number of receive antennas at the BS. In this paper, we
investigate the potential performance advantage of multiuser MBM (MU-MBM) in a
massive MIMO setting. Our results show that multiuser MBM (MU-MBM) can
significantly outperform other modulation schemes. For example, a bit error
performance achieved using 500 receive antennas at the BS in a massive MIMO
system using conventional modulation can be achieved using just 128 antennas
using MU-MBM. Even multiuser spatial modulation, and generalized spatial
modulation in the same massive MIMO settings require more than 200 antennas to
achieve the same bit error performance. Also, recognizing that the MU-MBM
signal vectors are inherently sparse, we propose an efficient MU-MBM signal
detection scheme that uses compressive sensing based reconstruction algorithms
like orthogonal matching pursuit (OMP), compressive sampling matching pursuit
(CoSaMP), and subspace pursuit (SP).


title:
Online Maximum Likelihood Estimation of the Parameters of Partially
  Observed Diffusion Processes

abstract:
  We revisit the problem of estimating the parameters of a partially observed
diffusion process, consisting of a hidden state process and an observed
process, with a continuous time parameter. The estimation is to be done online,
i.e. the parameter estimate should be updated recursively based on the
observation filtration. We provide a theoretical analysis of the stochastic
gradient ascent algorithm on the incomplete-data log-likelihood. The
convergence of the algorithm is proved under suitable conditions regarding the
ergodicity of the process consisting of state, filter, and tangent filter.
Additionally, our parameter estimation is shown numerically to have the
potential of improving suboptimal filters, and can be applied even when the
system is not identifiable due to parameter redundancies. Online parameter
estimation is a challenging problem that is ubiquitous in fields such as
robotics, neuroscience, or finance in order to design adaptive filters and
optimal controllers for unknown or changing systems. Despite this, theoretical
analysis of convergence is currently lacking for most of these algorithms. This
article sheds new light on the theory of convergence in continuous time.


title:
Characterization of phase transitions in a model ecosystem of sessile
  species

abstract:
  We consider a model ecosystem of sessile species competing for space. In
particular, we consider the system introduced in [Mathiesen et al. Phys. Rev.
Lett. 107, 188101 (2011)] where species compete according to a fixed
interaction network with links determined by a Bernoulli process. In the limit
of a small introduction rate of new species, the model exhibits a discontinuous
transition from a high-diversity state to a low-diversity state as the
interaction probability between species, $\gamma$, is increased from zero. Here
we explore the effects of finite introduction rates and system-size on the
phase transition by utilizing efficient parallel computing. We find that the
low state appears for $\gamma>\gamma_c$. As $\gamma$ is increased further, the
high state approaches to the low state, suggesting the possibility that the two
states merge at a high $\gamma$. We find that the fraction of time spent in the
high state becomes longer with higher introduction rates, but the availability
of the two states is rather insensitive to the value of the introduction rate.
Furthermore we establish a relation between the introduction rate and the
system size, which preserves the probability for the system to remain in the
high-diversity state.


title: Reducing Controversy by Connecting Opposing Views

abstract:
  Society is often polarized by controversial issues, that split the population
into groups of opposing views. When such issues emerge on social media, we
often observe the creation of 'echo chambers', i.e., situations where
like-minded people reinforce each other's opinion, but do not get exposed to
the views of the opposing side. In this paper we study algorithmic techniques
for bridging these chambers, and thus, reducing controversy. Specifically, we
represent the discussion on a controversial issue with an endorsement graph,
and cast our problem as an edge-recommendation problem on this graph. The goal
of the recommendation is to reduce the controversy score of the graph, which is
measured by a recently-developed metric based on random walks. At the same
time, we take into account the acceptance probability of the recommended edge,
which represents how likely the edge is to materialize in the endorsement
graph. We propose a simple model based on a recently-developed user-level
controversy score, that is competitive with state-of- the-art link-prediction
algorithms. We thus aim at finding the edges that produce the largest reduction
in the controversy score, in expectation. To solve this problem, we propose an
efficient algorithm, which considers only a fraction of all the combinations of
possible edges. Experimental results show that our algorithm is more efficient
than a simple greedy heuristic, while producing comparable score reduction.
Finally, a comparison with other state-of-the-art edge-addition algorithms
shows that this problem is fundamentally different from what has been studied
in the literature.


title: Exact solutions for scalar field cosmology in f(R) gravity

abstract:
  We look for exact solutions in scalar field cosmology. To achieve this we use
$f(R)$ modified gravity with a scalar field and do not specify the the form of
the $f(R)$ function. In particular, we study Friedmann universe assuming that
acceleration of the scalar curvature is negligible. We first present solutions
for special cases and then the general solution. Using initial conditions which
represent the universe at the present epoch, we evaluated the constants of
integration. This allows for the comparison of the scale factor in the new
solutions with that of the $\Lambda CDM$ solution, thereby affecting the age of
the universe in $f(R)$ gravity.


title:
Attractor metadynamics in terms of target points in slow-fast systems:
  adiabatic vs. symmetry protected flow in a recurrent neural network

abstract:
  In dynamical systems with distinct time scales the time evolution in phase
space may be influenced strongly by the fixed points of the fast subsystem.
Orbits then typically follow these points, performing in addition rapid
transitions between distinct branches on the time scale of the fast variables.
As the branches guide the dynamics of a system along the manifold of former
fixed points, they are considered transiently attracting states and the
intermittent transitions between branchescorrespond to state switching within
transient-state dynamics. A full characterization of the set of former fixed
points, the critical manifold, tends to be difficult in high-dimensional
dynamical systems such as large neural networks. Here we point out that an
easily computable subset of the critical manifold, the set of target points,
can be used as a reference for the investigation of high-dimensional slow-fast
systems. The set of target points corresponds in this context to the adiabatic
projection of a given orbit to the critical manifold. Applying our framework to
a simple recurrent neural network, we find that the scaling relation of the
Euclidean distance between the trajectory and its target points with the
control parameter of the slow time scale allows to distinguish an adiabatic
regime from a state that is effectively independent from target points.


title: Robust Spectral Inference for Joint Stochastic Matrix Factorization

abstract:
  Spectral inference provides fast algorithms and provable optimality for
latent topic analysis. But for real data these algorithms require additional
ad-hoc heuristics, and even then often produce unusable results. We explain
this poor performance by casting the problem of topic inference in the
framework of Joint Stochastic Matrix Factorization (JSMF) and showing that
previous methods violate the theoretical conditions necessary for a good
solution to exist. We then propose a novel rectification method that learns
high quality topics and their interactions even on small, noisy data. This
method achieves results comparable to probabilistic techniques in several
domains while maintaining scalability and provable optimality.


title: A generic property of Solovay's set $\Sigma$

abstract:
  We prove that Solovay's set $\Sigma$ is generic over the ground model via a
forcing notion whose order relation $\subseteq$-extends the given order
relation.


title: Transcendental extensions of a valuation domain of rank one

abstract:
  Let $V$ be a valuation domain of rank one and quotient field $K$. Let
$\overline{\hat{K}}$ be a fixed algebraic closure of the $v$-adic completion
$\hat K$ of $K$ and let $\overline{\hat{V}}$ be the integral closure of $\hat
V$ in $\overline{\hat{K}}$. We describe a relevant class of valuation domains
$W$ of the field of rational functions $K(X)$ which lie over $V$, which are
indexed by the elements $\alpha\in\overline{\hat{K}}\cup\{\infty\}$, namely,
$W=W_{\alpha}=\{\varphi\in K(X) \mid \varphi(\alpha)\in\overline{\hat{V}}\}$.
If $V$ is discrete and $\pi\in V$ is a uniformizer, then a valuation domain $W$
of $K(X)$ is of this form if and only if the residue field degree $[W/M:V/P]$
is finite and $\pi W=M^e$, for some $e\geq 1$, where $M$ is the maximal ideal
of $W$. In general, for $\alpha,\beta\in\overline{\hat{K}}$ we have
$W_{\alpha}=W_{\beta}$ if and only if $\alpha$ and $\beta$ are conjugated over
$\hat K$. Finally, we show that the set $\mathcal{P}^{{\rm irr}}$ of
irreducible polynomials over $\hat K$ endowed with an ultrametric distance
introduced by Krasner is homeomorphic to the space $\{W_{\alpha} \mid
\alpha\in\overline{\hat{K}}\}$ endowed with the Zariski topology.


title: Double parton scattering for perturbative transverse momenta

abstract:
  The cross section for transverse momentum dependent double parton scattering
involves transverse momentum dependent double parton distributions (DTMDs). In
the region of perturbative transverse momentum the DTMDs can be matched onto
collinear double parton distributions. We present the framework and results for
this matching, as well as the evolution equations for DTMDs in the region of
large distance between the two partons. We discuss explicit results for
one-loop matching coefficients and evolution kernels.


title: Dual Learning for Machine Translation

abstract:
  While neural machine translation (NMT) is making good progress in the past
two years, tens of millions of bilingual sentence pairs are needed for its
training. However, human labeling is very costly. To tackle this training data
bottleneck, we develop a dual-learning mechanism, which can enable an NMT
system to automatically learn from unlabeled data through a dual-learning game.
This mechanism is inspired by the following observation: any machine
translation task has a dual task, e.g., English-to-French translation (primal)
versus French-to-English translation (dual); the primal and dual tasks can form
a closed loop, and generate informative feedback signals to train the
translation models, even if without the involvement of a human labeler. In the
dual-learning mechanism, we use one agent to represent the model for the primal
task and the other agent to represent the model for the dual task, then ask
them to teach each other through a reinforcement learning process. Based on the
feedback signals generated during this process (e.g., the language-model
likelihood of the output of a model, and the reconstruction error of the
original sentence after the primal and dual translations), we can iteratively
update the two models until convergence (e.g., using the policy gradient
methods). We call the corresponding approach to neural machine translation
\emph{dual-NMT}. Experiments show that dual-NMT works very well on
English$\leftrightarrow$French translation; especially, by learning from
monolingual data (with 10% bilingual data for warm start), it achieves a
comparable accuracy to NMT trained from the full bilingual data for the
French-to-English translation task.


title: One-step green synthesis of graphene nanomesh by fluid-based method

abstract:
  A fluid-based method is demonstrated for preparing graphene nanomeshes (GNMs)
directly from pristine graphite flakes by a one-step process. The high
efficiency is attributed to the combination of fluid-assisted exfoliation and
perforation of the graphene sheets. Atomic force microscopy shows that the
as-produced GNMs are less than 1.5 nm thick. The total area of the pores within
1 um2 of the GNM sheet is estimated as ~0.15 um2 and the pore density as ~22
um-2, The yield of GNMs from pristine graphite powder and the power consumption
for per gram GNM synthesis are evaluated as 5 wt% and 120 kWh, respectively.
X-ray photoelectron spectroscopy, infrared spectroscopy, elemental analysis and
Raman spectroscopy results indicate the purity of the GNMs and thus it is a
green efficient method. The present work is expected to facilitate the
production of GNMs in large scale.


title:
Energy conservation in the 3D Euler equations on $\mathbb{T}^2\times
  \mathbb{R}_+$

abstract:
  The aim of this paper is to prove energy conservation for the incompressible
Euler equations in a domain with boundary. We work in the domain
$\mathbb{T}^2\times\mathbb{R}_+$, where the boundary is both flat and has
finite measure.
  However, first we study the equations on domains without boundary (the whole
space $\mathbb{R}^3$, the torus $\mathbb{T}^3$, and the hybrid space
$\mathbb{T}^2\times\mathbb{R}$). We make use of some of the arguments of Duchon
\& Robert ({\it Nonlinearity} {\bf 13} (2000) 249--255) to prove energy
conservation under the assumption that $u\in L^3(0,T;L^3(\mathbb{R}^3))$ and
one of the two integral conditions \begin{equation*} \lim_{|y|\to
0}\frac{1}{|y|}\int^T_0\int_{\mathbb{R}^3} |u(x+y)-u(x)|^3\,d x\,d t=0
\end{equation*} or \begin{equation*}
  \int_0^T\int_{\mathbb{R}^3}\int_{\mathbb{R}^3}\frac{|u(x)-u(y)|^3}{|x-y|^{4+\delta}}\,d
x\,d y<\infty,\qquad\delta>0, \end{equation*} the second of which is equivalent
to requiring $u\in L^3(0,T;W^{\alpha,3}(\mathbb{R}^3))$ for some $\alpha>1/3$.
  We then use the first of these two conditions to prove energy conservation
for a weak solution $u$ on $D_+:=\mathbb{T}^2\times \mathbb{R}_+$: we extend
$u$ a solution defined on the whole of $\mathbb{T}^2\times\mathbb{R}$ and then
use the condition on this domain to prove energy conservation for a weak
solution $u\in L^3(0,T;L^3(D_+))$ that satisfies \begin{equation*} \lim_{|y|\to
0}
\frac{1}{|y|}\int^{T}_{0}\iint_{\mathbb{T}^2}\int^\infty_{|y|}|u(t,x+y)-u(t,x)|^3
\,d x_3 \,d x_1 \,d x_2 \,d t=0, \end{equation*} and certain continuity
conditions near the boundary $\partial D_+=\{x_3=0\}$.


title: Parametrizations of degenerate density matrices

abstract:
  It turns out that a parametrization of degenerate density matrices requires a
parametrization of $\mathfrak{F}=U(n)/({U(k_1)\times U(k_2)\times \cdots \times
U(k_m)})\quad n=k_1 +\cdots + k_m $ where $U(k)$ denotes the set of all unitary
$k\times k$-matrices with complex entries. Unfortunately the parametrization of
this quotient space is quite involved. Our solution does not rely on Lie
algebra methods {directly,} but succeeds through the construction of suitable
sections for natural projections, by using techniques from the theory of
homogeneous spaces. We mention the relation to the Lie algebra back ground and
conclude with two concrete examples.


title: Local Subspace-Based Outlier Detection using Global Neighbourhoods

abstract:
  Outlier detection in high-dimensional data is a challenging yet important
task, as it has applications in, e.g., fraud detection and quality control.
State-of-the-art density-based algorithms perform well because they 1) take the
local neighbourhoods of data points into account and 2) consider feature
subspaces. In highly complex and high-dimensional data, however, existing
methods are likely to overlook important outliers because they do not
explicitly take into account that the data is often a mixture distribution of
multiple components.
  We therefore introduce GLOSS, an algorithm that performs local subspace
outlier detection using global neighbourhoods. Experiments on synthetic data
demonstrate that GLOSS more accurately detects local outliers in mixed data
than its competitors. Moreover, experiments on real-world data show that our
approach identifies relevant outliers overlooked by existing methods,
confirming that one should keep an eye on the global perspective even when
doing local outlier detection.


title: On a $p(\cdot)$-biharmonic problem with no-flux boundary condition

abstract:
  The study of fourth order partial differential equations has flourished in
the last years, however, a $p(\cdot)$-biharmonic problem with no-flux boundary
condition has never been considered before, not even for constant $p$. This is
an important step further, since surfaces that are impermeable to some
contaminants are appearing quite often in nature, hence the significance of
such boundary condition. By relying on several variational arguments, we obtain
the existence and the multiplicity of weak solutions to our problem. We point
out that, although we use a mountain pass type theorem in order to establish
the multiplicity result, we do not impose an Ambrosetti-Rabinowitz type
condition, nor a symmetry condition, on our nonlinearity $f$.


title:
Characterisation and testing of a prototype $6 \times 6$ cm$^2$ Argonne
  MCP-PMT

abstract:
  The Argonne micro-channel plate photomultiplier tube (MCP-PMT) is an offshoot
of the Large Area Pico-second Photo Detector (LAPPD) project, wherein \mbox{6
$\times$ 6 cm$^2$} sized detectors are made at Argonne National Laboratory.
Measurements of the properties of these detectors, including gain, time and
spatial resolution, dark count rates, cross-talk and sensitivity to magnetic
fields are reported. In addition, possible applications of these devices in
future neutrino and collider physics experiments are discussed.


title: On complex homogeneous singularities

abstract:
  In this article, we consider the singularity of an arbitrary homogeneous
polynomial with complex coefficients $f(x_0,\dots,x_n)$ at the origin of
$\mathbb C^{n+1}$, via the study of the monodromy characteristic polynomials
$\Delta_l(t)$, and the relation between the monodromy zeta function and the
Hodge spectrum of the singularity. We go further with $\Delta_1(t)$ in the case
$n=2$. This work is based on knowledge of multiplier ideals and local systems.


title:
Determining the Galactic Bar Parameters based on the Hercules and Wolf
  630 Stellar Streams

abstract:
  We have identified the four most significant features in the UV velocity
distribution of solar neighborhood stars: H1,H2 and W1,W2 in the Hercules and
Wolf 630 streams respectively. We have put the task of determining number of
characteristics of the central Galactic bar independently from each of the
identified features by assuming that the Hercules and Wolf 630 streams have a
bar-induced dynamical nature. The problem has been solved by constructing 2:1
resonant orbits in the rotating bar frame for each star in these streams.
Analysis of the resonant orbits found has shown that the bar pattern speed
\Omega_b lies within the range 45-52 km/s/kpc with a mean of 48.1+/-1.0
km/s/kpc, while the bar angle \theta_b is within the range 35-65 degrees with a
mean of 50+/-4 degrees. The results obtained are consistent with the view that
the Hercules and Wolf 630 streams could be formed by a single mechanism
associated with the fact that a long-term influence of the Galactic bar led to
a characteristic bimodal splitting of the UV velocity plane.


title:
Quantum optimal control via gradient ascent in function space and the
  time-bandwidth quantum speed limit

abstract:
  A gradient ascent method for optimal quantum control synthesis is presented
that employs a gradient derived with respect to the coefficients of a
functional basis expansion of the control. Restricting the space of allowable
controls to weighted sums of the Slepian sequences efficiently parameterizes
the control in terms of bandwidth, resolution and pulse duration. A bound
showing minimum time evolutions scaling with the inverse of the control
bandwidth [S. Lloyd and S. Montangero, PRL, 113, 010502, (2014)] is recovered
and the method is shown numerically to achieve the bound on entangling
two-qubit quantum gates.


title: Magnetic field geometry of the large globule CB 34

abstract:
  We report the results of optical polarimetric observations of a Bok globule
CB34 to study magnetic field structure on large scales ($10^5-10^6$ AU), which
is combined with archival sub-mm observations to characterize the magnetic
field structure of CB34 on small scales ($10^4 - 10^5$ AU). The optical
polarization measurements indicate that the magnetic field in the globule is
constrained to a maximum radius of $10^5$AU around the core, out to densities
not smaller than $10^4$cm$^{-3}$. Our study is mainly concentrated on two
submillimeter cores C1 and C2 of CB34. The direction of magnetic field of core
C2 is found to be nearly perpendicular to the CO outflow direction of the
globule. The magnetic field of core C1 is almost aligned with the minor axis of
the core which is typical for magnetically dominated star formation models. The
mean value of offset between the minor axis of core C2 and the outflow
direction is found to be $14^\circ$ which suggests that the direction of the
outflow is almost aligned with the minor axis of core C2. The magnetic field
strength in the plane-of-sky for cores C1 and C2 is estimated to be $\approx
34\mu$G and $\approx 70\mu$G.


title:
Anomalous Fraunhofer Interference in Epitaxial
  Superconductor-Semiconductor Josephson Junctions

abstract:
  We investigate patterns of critical current as a function of perpendicular
and in-plane magnetic fields in superconductor-semiconductor-superconductor
(SNS) junctions based on InAs/InGaAs heterostructures with an epitaxial Al
layer. This material system is of interest due to its exceptionally good
superconductor-semiconductor coupling, as well as large spin-orbit interaction
and g-factor in the semiconductor. Thin epitaxial Al allows the application of
large in-plane field without destroying superconductivity. For fields
perpendicular to the junction, flux focusing results in aperiodic node spacings
in the pattern of critical currents known as Fraunhofer patterns by analogy to
the related interference effect in optics. Adding an in-plane field yields two
further anomalies in the pattern. First, higher order nodes are systematically
strengthened, indicating current flow along the edges of the device, as a
result of confinement of Andreev states driven by an induced flux dipole;
second, asymmetries in the interference appear that depend on the field
direction and magnitude. A model is presented, showing good agreement with
experiment, elucidating the roles of flux focusing, Zeeman and spin-orbit
coupling, and disorder in producing these effects.


title:
Active Brownian particles and run-and-tumble particles separate inside a
  maze

abstract:
  A diverse range of natural and artificial self-propelled particles are known
and are used nowadays. Among them, active Brownian particles (ABPs) and
run-and-tumble particles (RTPs) are two important classes. We numerically study
non-interacting ABPs and RTPs strongly confined to different maze geometries in
two dimensions. We demonstrate that by means of geometrical confinement alone,
ABPs are separable from RTPs. By investigating Matryoshka-like mazes with
nested shells, we show that a circular maze has the best filtration efficiency.
Results on the mean first-passage time reveal that ABPs escape faster from the
center of the maze, while RTPs reach the center from the rim more easily.
According to our simulations and a rate theory, which we developed, ABPs in
steady state accumulate in the outermost region of the Matryoshka-like mazes,
while RTPs occupy all locations within the maze with nearly equal probability.
These results suggest a novel technique for separating different types of
self-propelled particles by designing appropriate confining geometries without
using chemical or biological agents.


title:
Characterization of electron detectors by time-of-flight in neutron
  \b{eta} decay experiments

abstract:
  Progress in neutron decay experiments requires better methods for the
characterization of electron detectors. I show that for such \b{eta}-decay
studies, electron time-of-flight can be used for in-situ calibration of
electron detectors. Energy resolution down to a few keV can be reached for the
lower part of the electron spectrum in neutron decay, where conventional
calibration methods come to their limit. Novel time-of-flight methods can also
be used to perform a complete experiment on electron backscattering from their
detectors.


title:
General Scalar-Tensor cosmology: Analytical solutions via Noether
  symmetry

abstract:
  We analyze the cosmology of a general Scalar-Tensor theory which encompasses
generalized Brans-Dicke theory, Gauss-Bonnet gravity, non-minimal derivative
gravity, generalized Galileon gravity and also the general k-essence type
models. Instead of taking into account phenomenological considerations we adopt
a Noether symmetry approach, as a physical criterion, to single out the form of
undetermined functions in the action. These specified functions symmetrize
equations of motion in the simplest possible form which result in exact
solutions. Demanding de Sitter, power-law and bouncing universe solutions in
the absence and presence of matter density leads to exploring new as well as
well-investigated models. We show that there are models for which dynamics of
the system allow transition from a decelerating phase (matter dominated era) to
an accelerating phase (dark energy epoch) and could also lead to general
Brans-Dicke with string correction without a self-interaction potential.
Furthermore, we classify the models based on phantom or quintessence dark
energy point of view. Finally, we obtain the condition for stability of a de
Sitter solution for which the solution is an attractor of the system.


title:
Exact correlations in the Lieb-Liniger model and detailed balance
  out-of-equilibrium

abstract:
  We study the density-density correlation function of the 1D Lieb-Liniger
model and obtain an exact expression for the small momentum limit of the static
correlator in the thermodynamic limit. We achieve this by summing exactly over
the relevant form factors of the density operator in the small momentum limit.
The result is valid for any eigenstate, including thermal and non-thermal
states. We also show that the small momentum limit of the dynamic structure
factors obeys a generalized detailed balance relation valid for any equilibrium
state.


title: A method to compute derivatives of functions of large complex matrices

abstract:
  A recently developed numerical method for the calculation of derivatives of
functions of general complex matrices, which can also be combined with implicit
matrix function approximations such as Krylov-Ritz type algorithms, is
presented. An important use case for the method in the context of lattice gauge
theory is the overlap Dirac operator at finite quark chemical potential.
Derivatives of the lattice Dirac operator are necessary for the computation of
conserved lattice currents or the fermionic force in Hybrid Monte-Carlo and
Langevin simulations. To calculate the overlap Dirac operator at finite
chemical potential the product of the sign function of a non-Hermitian matrix
with a vector has to be computed. For non-Hermitian matrices it is not possible
to efficiently approximate the sign function with polynomials or rational
functions. Implicit approximation algorithms, like Krylov-Ritz methods, that
depend on the source vector have to be used instead. Our method can also
provide derivatives of such implicit approximations. We show how a generalised
deflation prescription can be used to improve the performance of the method, if
some eigenvalues and eigenvectors of the matrix being differentiated are known.
To show that the method is efficient and well suited for practical calculations
we provide test results for the two-sided Lanczos approximation of the
finite-density overlap Dirac operator on SU(3) gauge field configurations on
lattices with sizes up to $14 \times 14^3$.


title:
Recurrent Neural Network Language Model Adaptation Derived Document
  Vector

abstract:
  In many natural language processing (NLP) tasks, a document is commonly
modeled as a bag of words using the term frequency-inverse document frequency
(TF-IDF) vector. One major shortcoming of the frequency-based TF-IDF feature
vector is that it ignores word orders that carry syntactic and semantic
relationships among the words in a document, and they can be important in some
NLP tasks such as genre classification. This paper proposes a novel distributed
vector representation of a document: a simple recurrent-neural-network language
model (RNN-LM) or a long short-term memory RNN language model (LSTM-LM) is
first created from all documents in a task; some of the LM parameters are then
adapted by each document, and the adapted parameters are vectorized to
represent the document. The new document vectors are labeled as DV-RNN and
DV-LSTM respectively. We believe that our new document vectors can capture some
high-level sequential information in the documents, which other current
document representations fail to capture. The new document vectors were
evaluated in the genre classification of documents in three corpora: the Brown
Corpus, the BNC Baby Corpus and an artificially created Penn Treebank dataset.
Their classification performances are compared with the performance of TF-IDF
vector and the state-of-the-art distributed memory model of paragraph vector
(PV-DM). The results show that DV-LSTM significantly outperforms TF-IDF and
PV-DM in most cases, and combinations of the proposed document vectors with
TF-IDF or PV-DM may further improve performance.


title:
Evolution of electric-field-induced quasibound states and resonances in
  one-dimensional open quantum systems

abstract:
  A comparative analysis of three different time-independent approaches to
studying open quantum structures in uniform electric field $\mathscr{E}$ was
performed using the example of one-dimensional attractive or repulsive
$\delta$-potential and surface that supports the Robin boundary condition. The
three considered methods exploit different properties of the scattering matrix
$S(\mathscr{E};E)$ as a function of energy $E$: its poles, real values, and
zeros of the second derivative of its phase. The essential feature of the
method of zeroing the resolvent, which produces complex energies, is the
unlimited growth of the wave function at infinity, which is, however,
eliminated by the time-dependent interpretation. The real energies at which the
unitary scattering matrix becomes real correspond to the largest possible
distortion, $S=+1$, or its absence at $S=-1$ which in either case leads to the
formation of quasibound states. Depending on their response to increasing
electric intensity, two types of field-induced positive energy quasibound
levels are identified: electron- and hole-like states. Their evolution and
interaction in enlarging field lead ultimately to the coalescence of pairs of
opposite states, with concomitant divergence of the associated dipole moments
in what is construed as an electric breakdown of the structure. The
characteristic features of the coalescence fields and energies are calculated
and the behavior of the levels in their vicinity is analyzed. Similarities
between the different approaches and their peculiarities are highlighted; in
particular, for zero-field bound state in limit of vanishing $\mathscr{E}$, all
three methods produce same results, with their outcomes deviating from each
other according to growing electric intensity.

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


title:
Deterministic Fully Dynamic Approximate Vertex Cover and Fractional
  Matching in $O(1)$ Amortized Update Time

abstract:
  We consider the problems of maintaining an approximate maximum matching and
an approximate minimum vertex cover in a dynamic graph undergoing a sequence of
edge insertions/deletions. Starting with the seminal work of Onak and Rubinfeld
[STOC 2010], this problem has received significant attention in recent years.
Very recently, extending the framework of Baswana, Gupta and Sen [FOCS 2011],
Solomon [FOCS 2016] gave a randomized dynamic algorithm for this problem that
has an approximation ratio of $2$ and an amortised update time of $O(1)$ with
high probability. This algorithm requires the assumption of an {\em oblivious
adversary}, meaning that the future sequence of edge insertions/deletions in
the graph cannot depend in any way on the algorithm's past output. A natural
way to remove the assumption on oblivious adversary is to give a deterministic
dynamic algorithm for the same problem in $O(1)$ update time. In this paper, we
resolve this question.
  We present a new {\em deterministic} fully dynamic algorithm that maintains a
$O(1)$-approximate minimum vertex cover and maximum fractional matching, with
an amortised update time of $O(1)$. Previously, the best deterministic
algorithm for this problem was due to Bhattacharya, Henzinger and Italiano
[SODA 2015]; it had an approximation ratio of $(2+\epsilon)$ and an amortised
update time of $O(\log n/\epsilon^2)$. Our results also extend to a fully
dynamic $O(f^3)$-approximate algorithm with $O(f^2)$ amortized update time for
the hypergraph vertex cover and fractional hypergraph matching problems, where
every hyperedge has at most $f$ vertices.


title:
On the Existence of the Kolmogorov Inertial Range in the Terrestrial
  Magnetosheath Turbulence

abstract:
  In the solar wind, power spectral density (PSD) of the magnetic field
fluctuations generally follow the so-called Kolmogorov spectrum f^-5/3 in the
inertial range, where the dynamics is thought to be dominated by nonlinear
interactions between counter-propagating incompressible Alfv\'en wave parquets.
These features are thought to be ubiquitous in space plasmas. The present study
gives a new and more complex picture of magnetohydrodynamics (MHD) turbulence
as observed in the terrestrial magnetosheath. The study uses three years of
in-situ data from the Cluster mission to explore the nature of the magnetic
fluctuations at MHD scales in different locations within the magnetosheath,
including flanks and subsolar regions. It is found that the magnetic field
fluctuations at MHD scales generally have a PSD close to f^-1 (shallower than
the Kolmogorov one f^-5/3) down to the ion characteristic scale, which recalls
the energy containing scales of solar wind turbulence. The Kolmogorov spectrum
is observed only away from the bow shock toward the flank and the magnetopause
regions in 17% of the analyzed time intervals. Measuring the magnetic
compressibility, it is shown that only a fraction (35%) of the observed
Kolmogorov spectra were populated by shear Alfv\'enic fluctuations, whereas the
majority of the events (65%) was found to be dominated by compressible
magnetosonic-like fluctuations, which contrasts with well-known turbulence
properties in the solar wind. This study gives a first comprehensive view of
the origin of the f^-1 and the transition to the Kolmogorov inertial range;
both questions remain controversial in solar wind turbulence.


title: Catalogue and Properties of {\delta} Scuti Stars in Binaries

abstract:
  The catalogue contains 199 confirmed cases of binary systems containing at
least one pulsating component of {\delta} Scuti type. The sample is divided
into subgroups in order to describe the properties and characteristics of the
{\delta} Sct type stars in binaries according to their Roche geometry.
Demographics describing quantitatively our knowledge for these systems as well
as the distributions of their pulsating components in the Mass-Radius,
Colour-Magnitude and Evolutionary Status-Temperature diagrams are presented and
discussed. It is shown that a threshold of ~13 days of the orbital period
regarding the influence of binarity on the pulsations is established. Finally,
the correlations between the pulsation periods and the orbital periods,
evolutionary status, and companion's gravity influence are updated based on the
largest sample to date.


title:
Towards Lifelong Self-Supervision: A Deep Learning Direction for
  Robotics

abstract:
  Despite outstanding success in vision amongst other domains, many of the
recent deep learning approaches have evident drawbacks for robots. This
manuscript surveys recent work in the literature that pertain to applying deep
learning systems to the robotics domain, either as means of estimation or as a
tool to resolve motor commands directly from raw percepts. These recent
advances are only a piece to the puzzle. We suggest that deep learning as a
tool alone is insufficient in building a unified framework to acquire general
intelligence. For this reason, we complement our survey with insights from
cognitive development and refer to ideas from classical control theory,
producing an integrated direction for a lifelong learning architecture.


title: The countable type properties in free paratopological groups

abstract:
  A space $X$ is of countable type (resp. subcountable type) if every compact
subspace $F$ of $X$ is contained in a compact subspace $K$ that is of countable
character (resp. countable pseudocharacter) in $X$. In this paper, we mainly
show that: (1) For a functionally Hausdorff space $X$, the free paratopological
group $FP(X)$ and the free abelian paratopological group $AP(X)$ are of
countable type if and only if $X$ is discrete; (2) For a functionally Hausdorff
space $X$, if the free abelian paratopological group $AP(X)$ is of subcountable
type then $X$ has countable pseudocharacter. Moreover, we also show that, for
an arbitrary Hausdorff $\mu$-space $X$, if $AP_{2}(X)$ or $FP_{2}(X)$ is
locally compact, then $X$ is homeomorphic to the topological sum of a compact
space and a discrete space.


title: Orthogonal Gaussian process models

abstract:
  Gaussian processes models are widely adopted for
nonparameteric/semi-parametric modeling. Identifiability issues occur when the
mean model contains polynomials with unknown coefficients. Though resulting
prediction is unaffected, this leads to poor estimation of the coefficients in
the mean model, and thus the estimated mean model loses interpretability. This
paper introduces a new Gaussian process model whose stochastic part is
orthogonal to the mean part to address this issue. This paper also discusses
applications to multi-fidelity simulations using data examples.


title: Reliability of digitized quantum annealing and the decay of entanglement

abstract:
  We performed a banged-digital-analog simulation of a quantum annealing
protocol in a two-qubit Nuclear Magnetic Resonance (NMR) quantum computer. Our
experimental simulation employed up to 235 Trotter steps, with more than 2000
gates (pulses), and we obtained a protocol success above 80%. Given the
exquisite control of the NMR quantum computer, we performed the simulation with
different noise levels. We thus analyzed the reliability of the quantum
annealing process, and related it to the level of entanglement produced during
the protocol. Although the presence of entanglement is not a sufficient
signature for a better-than-classical simulation, the level of entanglement
achieved relates to the fidelity of the protocol.


title:
Topological invariant and cotranslational symmetry in strongly
  interacting multi-magnon systems

abstract:
  It is still an outstanding challenge to characterize and understand the
topological features of strongly interacting states such as bound-states in
interacting quantum systems. Here, by introducing a cotranslational symmetry in
an interacting multi-particle quantum system, we systematically develop a
method to define a Chern invariant, which is a generalization of the well-known
Thouless-Kohmoto-Nightingale-den Nijs invariant, for identifying strongly
interacting topological states. As an example, we study the topological
multi-magnon states in a generalized Heisenberg XXZ model, which can be
realized by the currently available experiment techniques of cold atoms [Phys.
Rev. Lett. \textbf{111}, 185301 (2013); Phys. Rev. Lett. \textbf{111}, 185302
(2013)]. Through calculating the two-magnon excitation spectrum and the defined
Chern number, we explore the emergence of topological edge bound-states and
give their topological phase diagram. We also analytically derive an effective
single-particle Hofstadter superlattice model for a better understanding of the
topological bound-states. Our results not only provide a new approach to
defining a topological invariant for interacting multi-particle systems, but
also give insights into the characterization and understanding of strongly
interacting topological states.


title: Fractal Strichartz estimate for the wave equation

abstract:
  We consider Strichartz estimates for the wave equation with respect to
general measures which satisfy certain growth condition. In $\mathbb R^{3+1}$
we obtain the sharp estimate and in higher dimensions improve the previous
results.


title:
Stability in a scalar differential equation with multiple, distributed
  time delays

abstract:
  We consider a linear scalar delay differential equation (DDE), consisting of
two arbitrary distributed time delays. We formulate necessary conditions for
stability of the trivial solution which are independent of the distributions.
For the case of one discrete and one gamma distributed delay, we give an
explicit description of the region of stability of the trivial solution and
discuss how this depends on the model parameters.


title:
Strange Horizons: Understanding Causal Barriers Beyond General
  Relativity

abstract:
  This thesis explores two avenues into understanding the physics of black
holes and horizons beyond general relativity, via analogue models and Lorentz
violating theories. Analogue spacetimes have wildly different dynamics to
general relativity; this allows the possibility of non-Killing horizons in
stationary solutions. In the case of non-Killing horizons different definitions
of surface gravity are truly different quantities. This also has application to
modified theories of gravity, where there is no reason to expect all horizons
to be Killing horizons. In Lorentz violating theories, the situation becomes
even stranger, as Killing horizons are at best low energy barriers, but for
superluminal dispersion relations a true causal barrier, the universal horizon,
may be present. We investigate the nature of these universal horizons via a ray
tracing study, and delve into what happens near both the universal and Killing
horizons. From this study we determine the surface gravity of universal
horizons by the peeling properties of rays near the horizon and discuss
whether, and at what temperature these horizons radiate. Finally, we combine
our investigations of universal horizons and analogue spacetimes, and ask why
we have not seen a universal horizon in studies of analogue gravity.


title:
Phase Transitions of Chiral Spin Textures via Dipolar Coupling in
  Multilayered Films with Interfacial DMI

abstract:
  Under the correct conditions, Dzyaloshinskii-Moriya interactions (DMI) can
lead to topologically protected spin textures such as skyrmions. The
application of DMI for spin-based computation and memory technologies is
promising and requires a detailed consideration of the role intrinsic energies
have on stabilizing the diverse textures observed thus far. Here we
experimentally investigate the effect of dipolar energy from interlayer
coupling on the remanent spin textures found at room temperature for
interfacial DMI multilayers of [ Pt \ Co \ Ir ]$_{\times N}$. The total dipolar
energy is modified by increasing the number of layer repetitions N which result
in different phases of chiral magnetic textures. We use the phase transitions
to estimate the DMI energy present in the ultrathin films to be D = 2.1 $\pm$
0.1 mJ m$^{-2}$. Unlike traditional perpendicular magnetic anisotropy films,
these multilayer films with finite DMI exhibit isolated hedgehog skyrmion
bubbles as well as sub 100 nm labyrinth domains with cycloidal homochiral
N\'eel walls which are dependent on DMI as well as the total dipolar energy.


title: Inflation from the Finite Scale Gauged Nambu-Jona-Lasinio Model

abstract:
  The possibility to construct an inflationary universe scenario for the
finite-scale gauged Nambu-Jona-Lasinio model is investigated. This model can be
described by the Higgs-Yukawa type interaction model with the corresponding
compositeness scale. Therefore, the one-loop Higgs-Yukawa effective potential
is used with the compositeness condition for the study of inflationary
dynamics. We evaluate the fluctuations in the cosmic microwave background for
the model with a finite compositeness scale in the slow-roll approximation. We
find the remarkable dependence on the gauge group and the number of fermion
flavors. It is also proved that the model has similar behavior with the
$\phi^{4n}$ chaotic inflation and the Starobinsky model at the flat and steep
limits, respectively. It is demonstrated that realistic inflation consistent
with Planck data is possible for a range of theory parameters.


title:
Joint Optimization of Data Sponsoring and Edge Caching for Mobile Video
  Delivery

abstract:
  In this work, we study the joint optimization of edge caching and data
sponsoring for a video content provider (CP), aiming at reducing the content
delivery cost and increasing the CP's revenue. Specifically, we formulate the
joint optimization problem as a two-stage decision problem for the CP. In Stage
I, the CP determines the edge caching policy (for a relatively long time
period). In Stage II, the CP decides the real-time data sponsoring strategy for
each content request within the period. We first propose a Lyapunov-based
online sponsoring strategy in Stage II, which reaches 90% of the offline
maximum performance (benchmark). We then solve the edge caching problem in
Stage I based on the online sponsoring strategy proposed in Stage II, and show
that the optimal caching policy depends on the aggregate user request for each
content in each location. Simulations show that such a joint optimization can
increase the CP's revenue by 30%~100%, comparing with the purely data
sponsoring (i.e., without edge caching).


title:
Non-trivial Resource Amount Requirement in the Early Stage for
  Containing Fatal Diseases

abstract:
  During an epidemic control, the containment of the disease is usually
achieved through increasing devoted resource to shorten the duration of
infectiousness. However, the impact of this resource expenditure has not been
studied quantitatively. Using the well-documented cholera data, we observe
empirically that the recovery rate which is related to the duration of
infectiousness has a strong positive correlation with the average resource
devoted to the infected individuals. By incorporating this relation we build a
novel model and find that insufficient resource leads to an abrupt increase in
the infected population size, which is in marked contrast with the continuous
phase transitions believed previously. Counterintuitively, this abrupt phase
transition is more pronounced in the less contagious diseases, which usually
correspond to the most fatal ones. Furthermore, we find that even for a single
infection source, public resource needs to meet a significant amount, which is
proportional to the whole population size to ensure epidemic containment. Our
findings provide a theoretical foundation for efficient epidemic containment
strategies in the early stage.


title:
A comparison of untagged gamma-ray and tagged-neutron yields from
  241AmBe and 238PuBe sources

abstract:
  Untagged gamma-ray and tagged-neutron yields from 241AmBe and 238PuBe
mixed-field sources have been measured. Gamma-ray spectroscopy measurements
from 1 - 5 MeV were performed in an open environment using a CeBr3 detector and
the same experimental conditions for both sources. The shapes of the
distributions are very similar and agree well with previous data.
Tagged-neutron measurements from 2 - 6 MeV were performed in a shielded
environment using a NE-213 liquid-scintillator detector for the neutrons and a
YAP(Ce) detector to tag the 4.44 MeV gamma-rays associated with the
de-excitation of the first excited state of 12C. Again, the same experimental
conditions were used for both sources. The shapes of these distributions are
also very similar and agree well with previous data, each other, and the ISO
recommendation. Our 238PuBe source provides approximately 2.6 times more 4.44
MeV gamma-rays and 2.4 times more neutrons over the tagged-neutron energy
range, the latter in reasonable agreement with the original full-spectrum
source-calibration measurements performed at the time of their acquisition.


title: A Kolmogorov Consistency Theorem in the Multiple Probabilities Setting

abstract:
  We consider a system of weak* closed sets of finite-dimensional
distributions. We show that a corresponding system of random variables can be
defined on a probability space with a probability measure determined up to some
set of measures, provided that the sets of finite-dimensional distributions are
consistent.


title:
Soliton Solutions and their (In)stability for the Focusing
  Davey-Stewartson II Equation

abstract:
  We give a rigorous mathematical analysis of the one-soliton solution of the
focusing Davey-Stewartson II equation and a proof of its instability under
perturbation. Building on the fundamental perturbation analysis of Gadyl'shin
and Kiselev, we verify their Assumption 1 and use Fredholm determinants to
globalize their perturbation analysis.


title: Jacobi-Trudi determinants over finite fields

abstract:
  In this paper, we work toward answering the following question: given a
uniformly random algebra homomorphism from the ring of symmetric functions over
the integers to a finite field $\mathbb{F}_q$, what is the probability that the
Schur function $s_\lambda$ maps to zero? We show that this probability is
always at least $1/q$ and is asymptotically $1/q$. Moreover, we give a complete
classification of all shapes that can achieve probability $1/q$. In addition,
we identify certain families of shapes where the corresponding Schur functions
being sent to zero are independent events, and we look into the probability
that a Schur functions is mapped to nonzero values in $\mathbb{F}_q$.


title: Sources of Change for Modern Knowledge Organization Systems

abstract:
  Knowledge Organization Systems (e.g. taxonomies and ontologies) continue to
contribute benefits in the design of information systems by providing a shared
conceptual underpinning for developers, users, and automated systems. However,
the standard mechanisms for the management of KOSs changes are inadequate for
systems built on top of thousands of data sources or with the involvement of
hundreds of individuals. In this work, we review standard sources of change for
KOSs (e.g. institutional shifts; standards cycles; cultural and political;
distribution, etc) and then proceed to catalog new sources of change for KOSs
ranging from massively cooperative development to always-on automated
extraction systems. Finally, we reflect on what this means for the design and
management of KOSs.


title: Sliding Dictionary Based Sparse Representation For Action Recognition

abstract:
  The task of action recognition has been in the forefront of research, given
its applications in gaming, surveillance and health care. In this work, we
propose a simple, yet very effective approach which works seamlessly for both
offline and online action recognition using the skeletal joints. We construct a
sliding dictionary which has the training data along with their time stamps.
This is used to compute the sparse coefficients of the input action sequence
which is divided into overlapping windows and each window gives a probability
score for each action class. In addition, we compute another simple feature,
which calibrates each of the action sequences to the training sequences, and
models the deviation of the action from the each of the training data. Finally,
a score level fusion of the two heterogeneous but complementary features for
each window is obtained and the scores for the available windows are
successively combined to give the confidence scores of each action class. This
way of combining the scores makes the approach suitable for scenarios where
only part of the sequence is available. Extensive experimental evaluation on
three publicly available datasets shows the effectiveness of the proposed
approach for both offline and online action recognition tasks.


abstract:
  We use a three-body Continuum Discretized Coupled Channel (CDCC) model to
investigate Coulomb and nuclear effects in breakup and reaction cross sections.
The breakup of the projectile is simulated by a finite number of square
integrable wave functions. First we show that the scattering matrices can be
split in a nuclear term, and in a Coulomb term. This decomposition is based on
the Lippmann-Schwinger equation, and requires the scattering wave functions. We
present two different methods to separate both effects. Then, we apply this
separation to breakup and reaction cross sections of 7Li + 208Pb. For breakup,
we investigate various aspects, such as the role of the alpha + t continuum,
the angular-momentum distribution, and the balance between Coulomb and nuclear
effects. We show that there is a large ambiguity in defining the 'Coulomb' and
'nuclear' breakup cross sections, since both techniques, although providing the
same total breakup cross sections, strongly differ for the individual
components. We suggest a third method which could be efficiently used to
address convergence problems at large angular momentum. For reaction cross
sections, interference effects are smaller, and the nuclear contribution is
dominant above the Coulomb barrier. We also draw attention on different
definitions of the reaction cross section which exist in the literature, and
which may induce small, but significant, differences in the numerical values.


title: Should T2K run in dominant neutrino mode to detect CP violation ?

abstract:
  The main aim of the T2K experiment in Japan is to discover CP violation in
the leptonic sector by measuring the Dirac phase $\delta_{CP}$. For that
purpose T2K has already started collecting data in both neutrino and
antineutrino mode. But in this work we will show that, in T2K the main role of
the antineutrinos is to resolve the octant degeneracy. If the octant is known
then the pure neutrino run of T2K is capable to give the maximum CP
sensitivity. On the other hand in the experiment like NO$\nu$A, antineutrinos
are still useful even when octant is known. Thus we propose that let T2K run in
the dominant neutrino mode whereas the antineutrino component of the other
experiments can resolve the octant degeneracy in T2K. As an example we show
that if T2K is combined with the experiments NO$\nu$A and ICAL@INO, then T2K
will have the potential to discover CP violation with maximum sensitivity in
the dominant neutrino mode.


title: Noncommutative Cantor-Bendixson derivatives and scattered $C^*$-algebras

abstract:
  We analyze the sequence obtained by consecutive applications of the
Cantor-Bendixson derivative for a noncommutative scattered $C^*$-algebra
$\mathcal A$, using the ideal $\mathcal I^{At}(\mathcal A)$ generated by the
minimal projections of $\mathcal A$. With its help, we present some fundamental
results concerning scattered $C^*$-algebras, in a manner parallel to the
commutative case of scattered compact or locally compact Hausdorff spaces and
superatomic Boolean algebras. It also allows us to formulate problems which
have motivated the "cardinal sequences" programme in the classical topology, in
the noncommutative context.
  This leads to some new constructions of noncommutative scattered
$C^*$-algebras and new open problems. In particular, we construct a type $I$
$C^*$-algebra which is the inductive limit of stable ideals $\mathcal
A_\alpha$, along an uncountable limit ordinal $\lambda$, such that $\mathcal
A_{\alpha+1}/\mathcal A_\alpha$ is $*$-isomorphic to the algebra of all compact
operators on a separable Hilbert space and $\mathcal A_{\alpha+1}$ is
$\sigma$-unital and stable for each $\alpha<\lambda$, but $\mathcal A$ is not
stable and where all ideals of $\mathcal A$ are of the form $\mathcal
A_\alpha$. In particular, $\mathcal A$ is a nonseparable $C^*$-algebra with no
ideal which is maximal among the stable ideals.
  This answers a question of M. R\ordam in the nonseparable case. All the above
$C^*$-algebras $A_\alpha$s and $A$ satisfy the following version of the
definition of an AF algebra: any finite subset can be approximated from a
finite-dimensional subalgebra. Two more complex constructions based on the
language developed in this paper are presented in separate papers.


title:
A box full of chocolates: The rich structure of the nearby stellar halo
  revealed by Gaia and RAVE

abstract:
  The hierarchical structure formation model predicts that stellar halos should
form, at least partly, via mergers. If this was a predominant formation channel
for the Milky Way's halo, imprints of this merger history in the form of moving
groups or streams should exist also in the vicinity of the Sun. Here we study
the kinematics of halo stars in the Solar neighbourhood using the very recent
first data release from the Gaia mission, and in particular the TGAS dataset,
in combination with data from the RAVE survey. Our aim is to determine the
amount of substructure present in the phase-space distribution of halo stars
that could be linked to merger debris. To characterise kinematic substructure,
we measure the velocity correlation function in our sample of halo (low
metallicity) stars. We also study the distribution of these stars in the space
of energy and two components of the angular momentum, in what we call
"Integrals of Motion" space. The velocity correlation function reveals
substructure in the form of an excess of pairs of stars with similar
velocities, well above that expected for a smooth distribution. Comparison to
cosmological simulations of the formation of stellar halos indicate that the
levels found are consistent with the Galactic halo having been built fully via
accretion. Similarly, the distribution of stars in the space of "Integrals of
motion" is highly complex. A strikingly high fraction (between 58% and upto
73%) of the stars that are somewhat less bound than the Sun are on (highly)
retrograde orbits. A simple comparison to Milky Way-mass galaxies in
cosmological hydrodynamical simulations suggests that less than 1% have such
prominently retrograde outer halos. We also identify several other
statistically significant structures in "Integrals of Motion" space that could
potentially be related to merger events.


title:
Heterotic Supergravity with Internal Almost-K\"ahler Spaces, Instantons
  for $SO(32)$, or $E_8 \times E_8$, Gauge Groups, and Deformed Black Holes
  with Soliton, Quasiperiodic and/or Pattern-forming Structures

abstract:
  Heterotic supergravity with (1+3)--dimensional domain wall configurations and
(warped) internal, six dimensional, almost-K\"ahler manifolds $\ ^6\mathbf{X}$
are studied. Considering ten dimensional spacetimes with nonholonomic
distributions and conventional double fibrations, 2+2+...=2+2+3+3, and
associated $SU(3)$ structures on internal space, we generalize for real,
internal, almost symplectic gravitational structures the constructions with
gravitational and gauge instantons of tanh-kink type. They include the first
$\alpha ^{\prime}$ corrections to the heterotic supergravity action,
parameterized in a form to imply nonholonomic deformations of the Yang-Mills
sector and corresponding Bianchi identities. We show how it is possible to
construct a variety of solutions depending on the type of nonholonomic
distributions and deformations of 'prime' instanton configurations
characterized by two real supercharges. This corresponds to $\mathcal{N}=1/2$
supersymmetric, nonholonomic manifolds from the four dimensional point of view.
Our method provides a unified description of embedding nonholonomically
deformed tanh-kink-type instantons into half-BPS solutions of heterotic
supergravity. This allows us to elaborate new geometric methods of constructing
exact solutions of motion equations, with first order $\alpha ^{\prime}$
corrections to the heterotic supergravity. Such a formalism is applied for
general and/or warped almost-K\"ahler configurations, which allows us to
generate nontrivial (1+3)-d domain walls and black hole deformations determined
by quasiperiodic internal space structures. This formalism is utilized in our
associated publication [EPJC 77 (2017) 17, arXiv: 1608.01980] in order to
construct and study generic off-diagonal nonholonomic deformations of the Kerr
metric, encoding contributions from heterotic supergravity.


title: True randomness from an incoherent source

abstract:
  Quantum random number generators (QRNGs) harness the intrinsic randomness in
measurement processes: the measurement outputs are truly random given the input
state is a superposition of the eigenstates of the measurement operators. In
the case of \emph{trusted} devices, true randomness could be generated from a
mixed state $\rho$ so long as the system entangled with $\rho$ is well
protected. We propose a random number generation scheme based on measuring the
quadrature fluctuations of a single mode thermal state using an optical
homodyne detector. By mixing the output of a broadband amplified spontaneous
emission (ASE) source with a single mode local oscillator (LO) at a beam
splitter and performing differential photo-detection, we can selectively detect
the quadrature fluctuation of a single mode output of the ASE source, thanks to
the filtering function of the LO. Experimentally, a quadrature variance about
three orders of magnitude larger than the vacuum noise has been observed,
suggesting this scheme can tolerate much higher detector noise in comparison
with QRNGs based on measuring the vacuum noise. The high quality of this
entropy source is evidenced by the small correlation coefficients of the
acquired data. A Toeplitz hashing extractor is applied to generate unbiased
random bits from the Gaussian distributed raw data, achieving an efficiency of
5.12 bits per sample. The output of the Toeplitz extractor successfully passes
all the NIST statistical tests for random numbers.


title:
Quantum fluctuations and vortex-antivortex unbinding in the 2D BCS-BEC
  crossover

abstract:
  Very recently quasi two-dimensional (2D) systems made of attractive fermionic
alkali-metal atoms with a widely tunable interaction due to Fano-Feshbach
resonances have been realized. In this way it has been achieved the 2D
crossover from the Bardeen-Cooper-Schrieffer regime of weakly-interacting
Cooper pairs to the Bose-Einstein condensate regime strongly bound dimers.
These experiments pave the way to the investigation of 2D strongly-interacting
attractive fermions during the Berezinskii-Kosterlitz-Thouless (BKT) transition
from a low-temperature superfluid phase characterized by quasi-condensation to
a high-temperature normal phase, where vortex proliferation driven by quantum
and thermal fluctuations completely destroys superfluidity. In this paper we
discuss our preliminar theoretical results on the behavior of the BKT critical
temperature across the crossover. Our microscopic calculations are based on
functional integration taking into account renormalized Gaussian fluctuations
and the crucial 2D effect of vortex-antivortex unbinding.


title: Deciphering the Enigma of Wave-Particle Duality

abstract:
  A reasonable explanation of the confounding wave-particle duality of matter
is presented in terms of the reality of the wave nature of a particle. In this
view a quantum particle is an objectively real wave packet consisting of
irregular disturbances of underlying quantum fields. It travels holistically as
a unit and thereby acts as a particle. Only the totality of the entire wave
packet at any instance embodies all the conserved quantities, for example the
energy-momentum, rest mass, and charge of the particle, and as such must be
acquired all at once during detection. On this basis, many of the bizarre
behaviors observed in the quantum domain, such as wave function collapse, the
limitation of prediction to only a probability rather than a certainty, the
apparent simultaneous existence of a particle in more than one place, and the
inherent uncertainty can be adequately understood. The reality of comprehending
the wave function as an amplitude distribution of irregular disturbances
imposes the necessity of acquiring the wave function in its entirety for
detection. This is evinced by the observed certainty of wave function collapse
that supports the paradigm of reality of the wave function portrayed in this
article.


title: Nonlinear Graphene Quantum Capacitors for Electro-optics

abstract:
  Owing to its peculiar energy dispersion, the quantum capacitance property of
graphene can be exploited in a two-dimensional layered capacitor configuration.
Using graphene and boron nitride respectively as the electrodes and the
insulating dielectric, a strongly nonlinear behavior at zero bias and small
voltages is obtained. When the temperature is sufficiently low, the strong
nonlinear interaction emerging from the quantum capacitance exhibits a diverse
range of phenomena. The proposed structure could take over the functionalities
of nonlinear elements in many cryogenic quantum systems, and in particular,
quantum electro-optics. It is shown that ultrastrong coupling is easily reached
with small number of pump photons at temperatures around 1K and capacitor areas
of the order of $1\mu{\textrm{m}}^2$. A measure of anharmonicity is defined and
as potential applications, a qubit design as well as schemes for non-reciprocal
devices such as an electromagnetic frequency circulator are discussed.


title:
Application Specific Instrumentation (ASIN): A Bio-inspired Paradigm to
  Instrumentation using recognition before detection

abstract:
  In this paper we present a new scheme for instrumentation, which has been
inspired by the way small mammals sense their environment. We call this scheme
Application Specific Instrumentation (ASIN). A conventional instrumentation
system focuses on gathering as much information about the scene as possible.
This, usually, is a generic system whose data can be used by another system to
take a specific action. ASIN fuses these two steps into one. The major merit of
the proposed scheme is that it uses low resolution sensors and much less
computational overhead to give good performance for a highly specialised
application


title:
Existence of conformal metrics with constant scalar curvature and
  constant boundary mean curvature on compact manifolds

abstract:
  We study the problem of deforming a Riemannian metric to a conformal one with
nonzero constant scalar curvature and nonzero constant boundary mean curvature
on a compact manifold of dimension $n\geq 3$. We prove the existence of such
conformal metrics in the cases of $n=6,7$ or the manifold is spin and some
other remaining ones left by Escobar. Furthermore, in the positive Yamabe
constant case, by normalizing the scalar curvature to be $1$, there exists a
sequence of conformal metrics such that their constant boundary mean curvatures
go to $+\infty$.


title: Towards Blended Reactive Planning and Acting using Behavior Trees

abstract:
  In this paper, we show how a planning algorithm can be used to automatically
create and update a Behavior Tree (BT), controlling a robot in a dynamic
environment. The planning part of the algorithm is based on the idea of back
chaining. Starting from a goal condition we iteratively select actions to
achieve that goal, and if those actions have unmet preconditions, they are
extended with actions to achieve them in the same way. The fact that BTs are
inherently modular and reactive makes the proposed solution blend acting and
planning in a way that enables the robot to efficiently react to external
disturbances. If an external agent undoes an action the robot reexecutes it
without re-planning, and if an external agent helps the robot, it skips the
corresponding actions, again without replanning. We illustrate our approach in
two different robotics scenarios.


title:
Model independent analysis of $b \to (c,\,u)\,\tau\nu$ leptonic and
  semileptonic decays

abstract:
  Latest measurement of the ratio of branching ratios $R_D = \mathcal B(B \to
D\,\tau\,\nu)/\mathcal B(B \to D\,l\,\nu)$ and $R_{D^{\ast}} = \mathcal B(B \to
D^{\ast}\,\tau\,\nu)/\mathcal B(B \to D^{\ast}\,l\,\nu)$, where $l$ is either
an electron or muon, differs from the standard model expectation by $1.9\sigma$
and $3.3\sigma$, respectively. Similar tension has been observed in purely
leptonic $B \to \tau\nu$ decays as well. In this context, we consider the most
general effective Lagrangian in the presence of new physics and perform a model
independent analysis to explore various new physics couplings. Motivated by the
recently proposed new observables $R_D^{\tau} = R_D/\mathcal B(B \to \tau\nu)$
and $R_{D^{\ast}}^{\tau} = R_{D^{\ast}}/\mathcal B(B \to \tau\nu)$, we impose
$2\sigma$ constraints coming from $R_D^{\tau}$ and $R_{D^{\ast}}^{\tau}$ in
addition to the constraints coming from $R_D$, $R_{D^{\ast}}$, and $\mathcal
B(B \to \tau\nu)$ to constrain the new physics parameter space. We study the
impact of new physics on various observables related to $B_s \to
(D_s,\,D^{\ast}_s)\tau\nu$ and $B \to \pi\tau\nu$ decay processes.


title: Structural and decay properties of $Z=132,138$ superheavy nuclei

abstract:
  In this paper, we analyze the structural properties of $Z=132$ and $Z=138$
superheavy nuclei within the ambit of axially deformed relativistic mean-field
framework with NL$3^{*}$ parametrization and calculate the total binding
energies, radii, quadrupole deformation parameter, separation energies, density
distributions. We also investigate the phenomenon of shape coexistence by
performing the calculations for prolate, oblate and spherical configurations.
For clear presentation of nucleon distributions, the two-dimensional contour
representation of individual nucleon density and total matter density has been
made. Further, a competition between possible decay modes such as
$\alpha$-decay, $\beta$-decay and spontaneous fission of the isotopic chain of
superheavy nuclei with $Z=132$ within the range 312 $\le$ A $\le$ 392 and 318
$\le$ A $\le$ 398 for $Z=138$ is systematically analyzed within self-consistent
relativistic mean field model. From our analysis, we inferred that the
$\alpha$-decay and spontaneous fission are the principal modes of decay in
majority of the isotopes of superheavy nuclei under investigation apart from
$\beta$ decay as dominant mode of decay in $^{318-322}138$ isotopes.


title:
Inverse of the flow and moments of the free Jacobi process associated
  with a single projection

abstract:
  This paper is a companion to a series of papers devoted to the study of the
spectral distribution of the free Jacobi process associated with a single
projection. Actually, we notice that the flow solves a radial L\"owner equation
and as such, the general theory of L\"owner equations implies that it is
univalent in some connected region in the open unit disc. We also prove that
its inverse defines the Aleksandrov-Clark measure at $z=1$ of some Herglotz
function which is absolutely-continuous with an essentially bounded density. As
a by-product, we deduce that $z=1$ belongs only to the discrete spectrum of the
unitary operator whose spectral dynamics are governed by the flow. Moreover, we
use a previous result due to the first author in order to derive an explicit,
yet complicated, expression of the moments of both the unitary and the free
Jacobi processes. The paper is closed with some remarks on the boundary
behavior of the flow's inverse.


title:
On a Cahn--Hilliard--Darcy system for tumour growth with solution
  dependent source terms

abstract:
  We study the existence of weak solutions to a mixture model for tumour growth
that consists of a Cahn--Hilliard--Darcy system coupled with an elliptic
reaction-diffusion equation. The Darcy law gives rise to an elliptic equation
for the pressure that is coupled to the convective Cahn--Hilliard equation
through convective and source terms. Both Dirichlet and Robin boundary
conditions are considered for the pressure variable, which allows for the
source terms to be dependent on the solution variables.


title: Nonlinear Frequency-Division Multiplexing in the Focusing Regime

abstract:
  Achievable rates of the nonlinear frequency-division multiplexing (NFDM) and
wavelength-division multiplexing (WDM) subject to the same power and bandwidth
constraints are computed as a function of transmit power in the standard
single-mode fiber. NFDM achieves higher rates than WDM.


title: Revisiting SU(N) integrals

abstract:
  In this note, I revisit integrals over $\SU(N)$ of the form $ \int DU\,
U_{i_1j_1}\cdots U_{i_pj_p}\Ud_{k_1l_1}\cdots \Ud_{k_nl_n}$.
  While the case $p=n$ is well known, it seems that explicit expressions for
$p=n+N$ had not appeared in the literature. Similarities and differences, in
particular in the large $N$ limit, between the two cases are discussed


title:
On The Existence of a Holographic Description of the LHC Quark-Gluon
  Plasmas

abstract:
  Peripheral collisions of heavy ions can give rise to extremely intense
magnetic fields. It has been suggested that these fields might invalidate the
holographic description of the corresponding quark-gluon plasmas, assuming that
these can be modelled by strongly coupled field theories. In the case of the
plasmas produced in collisions at the RHIC facility (including in the beam
energy scans), it is known how to deal with this problem: one has to take into
account the large angular momenta generated in these plasmas, and the effects
of the baryonic chemical potential. But this does not work for the plasmas
produced in peripheral collisions at the LHC. However, these results neglect
some (less significant) aspects of bulk physics; could it be that the problem
is resolved by taking into account these lower-order effects? Here we use a
bulk dilatonic field (fully compatible with boundary data, as well as with the
asymptotically AdS character of the bulk geometry) as a model of these effects,
and show that this is unlikely to be the solution. Thus, the existence of a
consistent holographic description of the most extreme LHC plasmas remains open
to question.


title: Optothermal nonlinearity of silica aerogel

abstract:
  We report on the characterization of silica aerogel thermal optical
nonlinearity, obtained by z-scan technique. The results show that typical
silica aerogels have nonlinear optical coefficient similar to that of glass
$(\simeq 10^{-12} $m$^2/$W), with negligible optical nonlinear absorption. The
non\-li\-near coefficient can be increased to values in the range of $10^{-10}
$m$^2/$W by embedding an absorbing dye in the aerogel. This value is one order
of magnitude higher than that observed in the pure dye and in typical highly
nonlinear materials like liquid crystals.


title:
Experimental evidence for the importance of Hund's exchange interaction
  for the incoherence of the charge carriers in iron-based superconductors

abstract:
  Angle-resolved photoemission spectroscopy (ARPES) is used to study the
scattering rates of charge carriers from the hole pockets near Gamma in the
iron-based high-Tc hole doped superconductors KxBa1-xFe2As2 x=0.4 and
KxEu1-xFe2As2 x=0.55$ and the electron doped compound Ba(Fe1-xCox)2As2 x=0.075.
The scattering rate for any given band is found to depend linearly on energy,
indicating a non-Fermi liquid regime. The scattering rates in the hole-doped
compound are considerably larger than those in the electron-doped compounds. In
the hole-doped systems the scattering rate of the charge carriers of the inner
hole pocket is about three times bigger than the binding energy indicating that
the spectral weight is heavily incoherent. The strength of the scattering rates
and the difference between electron and hole doped compounds signals the
importance of Hund's exchange coupling for correlation effects in these
iron-based high-Tc superconductors. The experimental results are in qualitative
agreement with theoretical calculations in the framework of combined density
functional dynamical mean-field theory.


title: An introduction to the colloidal glass transition

abstract:
  Colloids are suspensions of small solid particles in a liquid, and exhibit
glassy behavior when the particle concentration is high. In these samples, the
particles are roughly analogous to individual molecules in a traditional glass.
This model system has been used to study the glass transition since the 1980's.
In this Viewpoint we summarize some of the intriguing behaviors of the glass
transition in colloids, and discuss open questions.


title:
Effect of Low Electric Fields on Alpha Scintillation Light Yield in
  Liquid Argon

abstract:
  Measurements were made of scintillation light yield of alpha particles from
the $^{222}$Rn decay chain within the DarkSide-50 liquid argon time projection
chamber. The light yield was found to increase as the applied electric field
increased, with alphas in a 200 V/cm electric field exhibiting a 2% increase in
light yield compared to alphas in no field.


title:
On Spectral Approximations With Nonstandard Weight Functions and Their
  Implementations to Generalized Chaos Expansions

abstract:
  In this manuscript, we analyze the expansions of functions in orthogonal
polynomials associated with a general weight function in a multidimensional
setting. Such orthogonal polynomials can be obtained by Gram-Schmidt
orthogonalization. However, in most cases, they are not eigenfunctions of some
singular Sturm-Liouville problem, as is the case for classical polynomials.
Therefore, standard results regarding convergence cannot be applied.
Furthermore, since in general, the weight functions are not a tensor product of
one-dimensional functions, the orthogonal polynomials are not a tensor product
of one-dimensional orthogonal polynomials, as well. In this work, we determine
the convergence rate using a comparison Lemma. We also present a spectrally
convergent, multidimensional, integration method. Numerical examples
demonstrate the efficacy of the proposed method. We show that the use of
nonstandard weight functions can allow for efficient integration of singular
functions. We also apply this method to Generalized Polynomial Chaos Expansions
in the case of dependent random variables.


title:
Real-space post-processing correction of thermal drift and piezoelectric
  actuator nonlinearities in scanning tunneling microscope images

abstract:
  We have developed a real-space method to correct distortion due to thermal
drift and piezoelectric actuator nonlinearities on scanning tunneling
microscope images using Matlab. The method uses the known structures typically
present in high-resolution atomic and molecularly-resolved images as an
internal standard. Each image feature (atom or molecule) is first identified in
the image. The locations of each feature's nearest neighbors (NNs) are used to
measure the local distortion at that location. The local distortion map across
the image is simultaneously fit to our distortion model, which includes thermal
drift in addition to piezoelectric actuator hysteresis and creep. The image
coordinates of the features and image pixels are corrected using an inverse
transform from the distortion model. We call this technique the thermal-drift,
hysteresis, and creep transform (DHCT). Performing the correction in real space
allows defects, domain boundaries, and step edges to be excluded with a spatial
mask. Additional real-space image analyses are now possible with these
corrected images. Using graphite(0001) as model system, we show lattice fitting
to the corrected image, averaged unit cell images, and symmetry-averaged unit
cell images. Statistical analysis of the distribution of the image features
around their best-fit lattice sites measures the aggregate noise in the image,
which can be expressed as feature confidence ellipsoids.


title:
Shear softening of Earth's inner core indicated by its high Poisson's
  ratio and elastic anisotropy

abstract:
  Earth's inner core exhibits an unusually high Poisson's ratio and noticeable
elastic anisotropy. The mechanisms responsible for these features are critical
for understanding the evolution of the Earth but remain unclear. This study
indicates that once the correct formula for the shear modulus is used, shear
softening can simultaneously explain the high Poisson's ratio and strong
anisotropy of the inner core. Body-centred-cubic (bcc) iron shows shear
instability at the pressures found in the inner-core and can be dynamically
stabilized by temperature and light elements. It is very likely that some
combinations of light elements stabilize the bcc iron alloy under inner-core
conditions. Such a bcc phase would exhibit significant shear softening and
match the geophysical constraints of the inner core. Identifying which light
elements and what concentrations of these elements stabilize the bcc phase will
provide critical information on the light elements of the inner core.


title: Low Codimension Strata of the Singular Locus of Moduli of Level Curves

abstract:
  We further analyze the moduli space of stable curves with level structure
provided by Chiodo and Farkas in \cite{AA}. Their result builds upon Harris and
Mumford analysis of the locus of singularities of the moduli space of curves
and shows in particular that for levels 2, 3, 4, and 6 the locus of
noncanonical singularities is completely analogous to the locus described by
Harris and Mumford, it has codimension 2 and arises from the involution of
elliptic tails carrying a trivial level structure. For the remaining levels (5,
7, and beyond), the picture also involves components of higher codimension. We
show that there exists a component of codimension 3 for levels $\ell=5$ and
$\ell\geqslant 7$ with the only exception of level 12. We also show that there
exists a component of codimension 4 for $\ell=12$.


title: On the phylogeny graphs of degree-bounded digraphs

abstract:
  Hefner [K. A. S. Hefner, K. F. Jones, S. -R. Kim, R. J. Lundgren and F. S.
Roberts: $(i,j)$ competition graphs, Discrete Applied Mathematics, 32, (1991)
241-262] characterized acyclic digraphs each vertex of which has inderee and
outdegree at most two and whose competition graphs are interval. They called
acyclic digraphs each vertex of which has inderee and outdegree at most two
$(2,2)$ digraphs. In this paper, we study the phylogeny graphs of $(2,2)$
digraphs. Especially, we give a sufficient condition and necessary conditions
for $(2,2)$ digraphs having chordal phylogeny graphs. Phylogeny graphs are also
called moral graphs in Bayesian network theory. Our work is motivated by
problems related to evidence propagation in a Bayesian network for which it is
useful to know which acyclic digraphs have their moral graphs being chordal.


title:
Foldy-Wouthuysen transfer matrix method for Dirac tunneling through
  monolayer graphene with a mass gap

abstract:
  We provide a transfer matrix method for the Foldy-Wouthuysen representation
of the Dirac equation. We develop the relationship between the reflection and
transmission coefficients of the Dirac spinors and the wavefunction in the
transformed representation. We develop a WKB approximation for Dirac fermions
which has the same elegant form as the WKB solution to Schr\"{o}dinger's
equation. Our WKB approximation is to all orders and includes the
semi-classical turning point. We provide an extension to fully 2-dimensional
periodic structures by Fourier methods for band engineering. We verify our
methods for all energies by comparison with analytic solutions developed in the
Dirac spinor representation. We also include a rich appendix detailing our
research into the Green's functions of Dirac fermions.


title: Wronskians and Linear Dependence of Formal Power Series

abstract:
  We give a new proof of the fact that the vanishing of generalized Wronskians
implies linear dependence of formal power series in serveral variables. Our
results are also valid for quotients of germs of analytic functions.


title: Computing the Braid Monodromy of Completely Reducible $n$-gonal Curves

abstract:
  Braid monodromy is an important tool for computing invariants of curves and
surfaces. In this paper, the \emph{rectangular braid diagram (RBD)} method is
proposed to compute the braid monodromy of a completely reducible $n$-gonal
curve, i.e. the curves in the form $(y-y_1(x))...(y-y_n(x))=0$ where $n\in
\mathbb{Z}^{+}$ and $y_i\in \mathbb{C}[x]$. Also, an algorithm is presented to
compute the Alexander polynomial of these curve complements using Burau
representations of braid groups. Examples for each computation are provided.


title: Wounded quarks at the LHC

abstract:
  We review the results of the wounded quark model, with a stress on
eccentricity observables in small systems. A new element is a presentation of
symmetric cumulants for the elliptic and triangular flow correlations, obtained
in the wounded-quark approach.


title: Simulating confined particles with a flat density profile

abstract:
  Particle simulations confined by sharp walls usually develop an oscillatory
density profile. For some applications, most notably soft matter liquids, this
behavior is often unrealistic and one expects a monotonic density climb
instead. To reconcile simulations with experiments, we propose mirror-and-shift
boundary conditions where each interface is mapped to a distant part of itself.
The main result is that the particle density increases almost monotonically
from zero to bulk, over a short distance of about one particle diameter. The
method is applied to simulate a polymer brush in explicit solvent, grafted on a
flat silicon substrate. The simulated density profile agrees favorably with
neutron reflectometry measurements and self-consistent field theory results.


title:
Improving a Credit Scoring Model by Incorporating Bank Statement Derived
  Features

abstract:
  In this paper, we investigate the extent to which features derived from bank
statements provided by loan applicants, and which are not declared on an
application form, can enhance a credit scoring model for a New Zealand lending
company. Exploring the potential of such information to improve credit scoring
models in this manner has not been studied previously. We construct a baseline
model based solely on the existing scoring features obtained from the loan
application form, and a second baseline model based solely on the new bank
statement-derived features. A combined feature model is then created by
augmenting the application form features with the new bank statement derived
features. Our experimental results using ROC analysis show that a combined
feature model performs better than both of the two baseline models, and show
that a number of the bank statement-derived features have value in improving
the credit scoring model. The target data set used for modelling was highly
imbalanced, and Naive Bayes was found to be the best performing model, and
outperformed a number of other classifiers commonly used in credit scoring,
suggesting its potential for future use on highly imbalanced data sets.