title: Local geodesics for plurisubharmonic functions

abstract:
  We study geodesics for plurisubharmonic functions from the Cegrell class
${\mathcal F}_1$ on a bounded hyperconvex domain of ${\mathbb C}^n$ and show
that, as in the case of metrics on K\"{a}hler compact menifolds, they linearize
an energy functional. As a consequence, we get a uniqueness theorem for
functions from ${\mathcal F}_1$ in terms of total masses of certain mixed
Monge-Amp\`ere currents. Geodesics of relative extremal functions are
considered and a reverse Brunn-Minkowski inequality is proved for capacities of
multiplicative combinations of multi-circled compact sets. We also show that
functions with strong singularities generally cannot be connected by
(sub)geodesic arks.


title:
A short note on extension theorems and their connection to universal
  consistency in machine learning

abstract:
  Statistical machine learning plays an important role in modern statistics and
computer science. One main goal of statistical machine learning is to provide
universally consistent algorithms, i.e., the estimator converges in probability
or in some stronger sense to the Bayes risk or to the Bayes decision function.
Kernel methods based on minimizing the regularized risk over a reproducing
kernel Hilbert space (RKHS) belong to these statistical machine learning
methods. It is in general unknown which kernel yields optimal results for a
particular data set or for the unknown probability measure. Hence various
kernel learning methods were proposed to choose the kernel and therefore also
its RKHS in a data adaptive manner. Nevertheless, many practitioners often use
the classical Gaussian RBF kernel or certain Sobolev kernels with good success.
The goal of this short note is to offer one possible theoretical explanation
for this empirical fact.


title: Integrating Know-How into the Linked Data Cloud

abstract:
  This paper presents the first framework for integrating procedural knowledge,
or "know-how", into the Linked Data Cloud. Know-how available on the Web, such
as step-by-step instructions, is largely unstructured and isolated from other
sources of online knowledge. To overcome these limitations, we propose
extending to procedural knowledge the benefits that Linked Data has already
brought to representing, retrieving and reusing declarative knowledge. We
describe a framework for representing generic know-how as Linked Data and for
automatically acquiring this representation from existing resources on the Web.
This system also allows the automatic generation of links between different
know-how resources, and between those resources and other online knowledge
bases, such as DBpedia. We discuss the results of applying this framework to a
real-world scenario and we show how it outperforms existing manual
community-driven integration efforts.


title:
Correlations between the final momenta of electrons and their initial
  phase-space distribution in the process of tunnel ionization

abstract:
  We present both full quantum mechanical and semiclassical calculations of
above threshold ionization (ATI) of a hydrogen atom in the tunneling regime by
a few-cycle linearly polarized infrared laser pulse. As a quantum treatment, we
applied the direct integration of the time dependent Schr\"odinger equation
(TDSE). In the semiclassical approximation (SCA), it is assumed that wavepacket
propagation in the post-tunneling process can be well described within the
classical framework. With these two methods, we analyze the similarities and
deviations for ionization of the hydrogen atom. We found that the 3 dimensional
semiclassical method can describe reasonably well the momentum correlation
pattern of the ATI peaks. We also show good agreement between the results
obtained by TDSE method and the semi-classical method. Furthermore, with the
semiclassical approximation we clearly identify and separate the regions in
momentum distributions of the ejected electrons according to initial
conditions. We illustrate the corresponding regions with typical electron
trajectories.


title:
On the average value of the least common multiple of $k$ positive
  integers

abstract:
  We deduce an asymptotic formula with error term for the sum
$\sum_{n_1,\ldots,n_k \le x} f([n_1,\ldots, n_k])$, where $[n_1,\ldots, n_k]$
stands for the least common multiple of the positive integers $n_1,\ldots, n_k$
($k\ge 2$) and $f$ belongs to a large class of multiplicative arithmetic
functions, including, among others, the functions $f(n)=n^r$, $\varphi(n)^r$,
$\sigma(n)^r$ ($r>-1$ real), where $\varphi$ is Euler's totient function and
$\sigma$ is the sum-of-divisors function. The proof is by elementary arguments,
using the extension of the convolution method for arithmetic functions of
several variables, starting with the observation that given a multiplicative
function $f$, the function of $k$ variables $f([n_1,\ldots,n_k])$ is
multiplicative.


title: Bounding the search number of graph products

abstract:
  In this paper, we provide results for the search number of the Cartesian
product of graphs. We consider graphs on opposing ends of the spectrum: paths
and cliques. Our main result determines the pathwidth of the product of cliques
and provides a lower bound for the search number of the product of cliques. A
consequence of this result is a bound for the search number of arbitrary graphs
G and H based on their respective clique numbers.


title:
Structure constants of shs$[\lambda]$: the deformed-oscillator point of
  view

abstract:
  We derive and spell out the structure constants of the $\mathbb{Z}_2$-graded
algebra $\mathfrak{shs}[\lambda]\,$ by using deformed-oscillators techniques in
$Aq(2;\nu)\,$, the universal enveloping algebra of the Wigner-deformed
Heisenberg algebra in 2 dimensions. The use of Weyl ordering of the deformed
oscillators is made throughout the paper, via the symbols of the operators and
the corresponding associative, non-commutative star product. The deformed
oscillator construction was used by Vasiliev in order to construct the higher
spin algebras in three spacetime dimensions. We derive an expression for the
structure constants of $\mathfrak{shs}[\lambda]\,$ and show that they must obey
a recurrence relation as a consequence of the associativity of the star
product. We solve this condition and show that the $\mathfrak{hs}[\lambda]\,$
structure constants are given by those postulated by Pope, Romans and Shen for
the Lone Star product.


title: Fibonacci anyon excitations of one-dimensional dipolar lattice bosons

abstract:
  We study a system of dipolar bosons in a one-dimensional optical lattice
using exact diagonalization and density matrix renormalization group methods.
In particular, we analyze low energy properties of the system at an average
filling of 3/2 atoms per lattice site. We identify the region of the parameter
space where the system has non-Abelian Fibonacci anyon excitations that
correspond to fractional domain walls between different charge-density-waves.
When such one-dimensional systems are combined into a two-dimensional network,
braiding of Fibonacci anyon excitations has potential application for fault
tolerant, universal, topological quantum computation. Contrary to previous
calculations, our results also demonstrate that super-solid phases are not
present in the phase diagram for the discussed 3/2 average filling. Instead,
decreasing the value of the nearest-neighbor tunneling strength leads to a
direct, Berezinskii-Kosterlitz-Thouless, super-fluid to charge-density-wave
quantum phase transition.


title:
Large time behaviour of solutions to parabolic equations with Dirichlet
  operators and nonlinear dependence on measure data

abstract:
  We study large time behaviour of solutions of the Cauchy problem for
equations of the form $\partial_tu-L u+\lambda u=f(x,u)+g(x,u)\cdot\mu$, where
$L$ is the operator associated with a regular lower bounded semi-Dirichlet form
${\mathcal{E}}$ and $\mu$ is a nonnegative bounded smooth measure with respect
to the capacity determined by ${\mathcal{E}}$. We show that under the
monotonicity and some integrability assumptions on $f,g$ as well as some
assumptions on the form ${\mathcal{E}}$, $u(t,x)\rightarrow v(x)$ as
$t\rightarrow\infty$ for quasi-every $x$, where $v$ is a solution of some
elliptic equation associated with our parabolic equation. We also provide the
rate convergence. Some examples illustrating the utility of our general results
are given.


title: Piezoelectricity in asymmetrically strained bilayer graphene

abstract:
  We study the electronic properties of commensurate faulted bilayer graphene
by diagonalizing the one-particle Hamiltonian of the bilayer system in a
complete basis of Bloch states of the individual graphene layers. Our novel
approach is very general and can be easily extended to any commensurate
graphene-based heterostructure. Here, we consider three cases: i) twisted
bilayer graphene, ii) bilayer graphene where triaxial stress is applied to one
layer, and iii) bilayer graphene where uniaxial stress is applied to one layer.
We show that the resulting superstructures can be divided into distinct
classes, depending on the twist angle or the magnitude of the induced strain.
The different classes are distinguished from each other by the interlayer
coupling mechanism, resulting in fundamentally different low-energy physics.
For the cases of triaxial and uniaxial stress, the individual graphene layers
tend to decouple and we find significant charge transfer between the layers. In
addition, this piezoelectric effect can be tuned by applying a perpendicular
electric field. Finally, we show how our approach can be generalized to
multilayer systems.


title:
On the block counting process and the fixation line of the
  Bolthausen-Sznitman coalescent

abstract:
  The block counting process and the fixation line of the Bolthausen-Sznitman
coalescent are analyzed. Spectral decompositions for their generators and
transition probabilities are provided leading to explicit expressions for
functionals such as hitting probabilities and absorption times. It is
furthermore shown that the block counting process and the fixation line of the
Bolthausen-Sznitman $n$-coalescent, properly scaled, converge in the Skorohod
topology to the Mittag-Leffler process and Neveu's continuous-state branching
process respectively as the sample size $n$ tends to infinity. Strong relations
to Siegmund duality and to Mehler semigroups and self-decomposability are
pointed out.


title: The unusually strong coronal emission lines of SDSS J1055+5637

abstract:
  Many Seyfert galaxies display weak 'coronal' emission features corresponding
to [Fe VII], [Fe XI] and [Fe XIV] in their optical spectra, whereas elsewhere
these lines seem to be entirely absent. These lines appear to highlight zones
in the nucleus irradiated by high-energy photons. The presence of these zones
and the conditions therein as determined by the relative line strengths and
profiles impose important constraints on the physical models of active galactic
nuclei, and Seyferts in particular. In 2009 the discovery was announced of the
highly unusual spectrum of SDSS J0952+2143, where the coronal lines are
exceptionally strong. This paper presents a second object with abnormally
strong coronal features, SDSS J1055+5637. The spectrum, line ratios and related
parameters are compared to those of SDSS J0952+2143, three AGN with moderate
coronal lines and one where the coronal lines are missing altogether. Possible
mechanisms are discussed that may account for the stronger than usual coronal
features.


title:
Robust adaptive efficient estimation for semi-Markov nonparametric
  regression models

abstract:
  We consider the nonparametric robust estimation problem for regression models
in continuous time with semi-Markov noises. An adaptive model selection
procedure is proposed. Under general moment conditions on the noise
distribution a sharp non-asymptotic oracle inequality for the robust risks is
obtained and the robust efficiency is shown. It turns out that for semi-Markov
models the robust minimax convergence rate may be faster or slower than the
classical one.


title:
Twist in the bias-dependence of spin-torques in magnetic tunnel
  junctions

abstract:
  The spin-torque in magnetic tunnel junctions possesses two components that
both depend on the applied voltage. Here, we develop a new method for the
accurate extraction of this bias-dependence from experiments over large voltage
ranges. We study several junctions with different magnetic layer structures of
the top electrode. Our results obtained on junctions with symmetric CoFeB
electrodes agree well with theoretical calculations. The bias-dependences of
asymmetric samples, with top electrodes containing NiFe, however, are twisted
compared to the quadratic form generally assumed. Our measurements reveal the
complexity of spin-torque mechanisms at large bias.


title: Thermodynamics of quark matter with a chiral imbalance

abstract:
  We show how a scheme of rewriting a divergent momentum integral can
conciliate results obtained with the Nambu--Jona-Lasinio model and recent
lattice results for the chiral transition in the presence of a chiral imbalance
in quark matter. Purely vacuum contributions are separated from
medium-dependent regularized momentum integrals in such a way that one is left
with ultraviolet divergent momentum integrals that depend on vacuum quantities
only. The scheme is applicable to other commonly used effective models to study
quark matter with a chiral imbalance, it allows us to identify the source of
their difficulties in reproducing the qualitative features of lattice results,
and enhances their predictability and uses in other applications.


title:
Exactly solvable time-dependent models of two interacting two-level
  systems

abstract:
  Two coupled two-level systems placed under external time-dependent magnetic
fields are modeled by a general Hamiltonian endowed with a symmetry that
enables us to reduce the total dynamics into two independent two-dimensional
sub-dynamics. Each of the sub-dynamics is shown to be brought into an exactly
solvable form by appropriately engineering the magnetic fields and thus we
obtain an exact time evolution of the compound system. Several physically
relevant and interesting quantities are evaluated exactly to disclose
intriguing phenomena in such a system.


title:
Search for metastable heavy charged particles with large ionization
  energy loss in pp collisions at $\sqrt{s} = 13$ TeV using the ATLAS
  experiment

abstract:
  This paper presents a search for massive charged long-lived particles
produced in pp collisions at $\sqrt{s}=$ 13 TeV at the LHC using the ATLAS
experiment. The dataset used corresponds to an integrated luminosity of 3.2
fb$^{-1}$. Many extensions of the Standard Model predict the existence of
massive charged long-lived particles, such as $R$-hadrons. These massive
particles are expected to be produced with a velocity significantly below the
speed of light, and therefore to have a specific ionization higher than any
Standard Model particle of unit charge at high momenta. The Pixel subsystem of
the ATLAS detector is used to measure the ionization energy loss of
reconstructed charged particles and to search for such highly ionizing
particles. The search presented here has much greater sensitivity than a
similar search performed using the ATLAS detector in the $\sqrt{s}=$ 8 TeV
dataset, thanks to the increase in expected signal cross-section due to the
higher center-of-mass energy of collisions, to an upgraded detector with a new
silicon layer close to the interaction point, and to analysis improvements. No
significant deviation from Standard Model background expectations is observed,
and lifetime-dependent upper limits on $R$-hadron production cross-sections and
masses are set. Gluino $R$-hadrons with lifetimes above 0.4 ns and decaying to
$q\bar{q}$ plus a 100 GeV neutralino are excluded at the 95% confidence level,
with lower mass limit ranging between 740 GeV and 1590 GeV. In the case of
stable $R$-hadrons the lower mass limit at the 95% confidence level is 1570
GeV.


title: The obstacle problem for nonlinear integro-differential operators

abstract:
  We investigate the obstacle problem for a class of nonlinear equations driven
by nonlocal, possibly degenerate, integro-differential operators, whose model
is the fractional $p$-Laplacian operator with measurable coefficients. Amongst
other results, we will prove both the existence and uniqueness of the solutions
to the obstacle problem, and that these solutions inherit regularity
properties, such as boundedness, continuity and H\"older continuity (up to the
boundary), from the obstacle.


title: Generalized multicritical one-matrix models

abstract:
  We show that there exists a simple generalization of Kazakov's multicritical
one-matrix model, which interpolates between the various multicritical points
of the model. The associated multicritical potential takes the form of a power
series with a heavy tail, leading to a cut of the potential and its derivative
at the real axis, and reduces to a polynomial at Kazakov's multicritical
points. From the combinatorial point of view the generalized model allows
polygons of arbitrary large degrees (or vertices of arbitrary large degree,
when considering the dual graphs), and it is the weight assigned to these large
order polygons which brings about the interpolation between the multicritical
points in the one-matrix model.


title: Chern class of Schubert cells in the flag manifold and related algebras

abstract:
  We discuss a relationship between Chern-Schwartz-MacPherson classes for
Schubert cells in flag manifolds, Fomin-Kirillov algebra, and the generalized
nil-Hecke algebra. We show that nonnegativity conjecture in Fomin-Kirillov
algebra implies the nonnegativity of the Chern-Schwartz-MacPherson classes for
Schubert cells in flag manifolds for type A. Motivated by this connection, we
also prove that the (equivariant) Chern-Schwartz-MacPherson classes for
Schubert cells in flag manifolds are certain summations of the structure
constants of the equivariant cohomology of the Bott-Samelson varieties. We also
discuss the refined positivity conjectures of the Chern-Schwartz-MacPherson
classes for Schubert cells motivated by the nonnegativity conjecture in
Fomin-Kirillov algebra.


title: Nonsimplicity of certain universal $\mathrm{C}^\ast$-algebras

abstract:
  Given $n\geq 2$, $z_{ij}\in\mathbb{T}$ such that $z_{ij}=\overline z_{ji}$
for $1\leq i,j\leq n$ and $z_{ii}=1$ for $1\leq i\leq n$, and integers
$p_1,...,p_n\geq 1$, we show that the universal $\mathrm{C}^*$-algebra
generated by unitaries $u_1,...,u_n$ such that
$u_i^{p_i}u_j^{p_j}=z_{ij}u_j^{p_j}u_i^{p_i}$ for $1\leq i,j \leq n$ is not
simple if at least one exponent $p_i$ is at least two. We indicate how the
method of proof by `working with various quotients' can be used to establish
nonsimplicity of universal $\mathrm{C}^*$-algebras in other cases.


title:
Electrical conductivity of the lowermost mantle explains absorption of
  core torsional waves at the equator

abstract:
  Torsional Alfv{\'e}n waves propagating in the Earth's core have been inferred
by inversion techniques applied to geomagnetic models. They appear to propagate
across the core but vanish at the equator, exchanging angular momentum between
core and mantle. Assuming axial symmetry, we find that an electrically
conducting layer at the bottom of the mantle can lead to total absorption of
torsional waves that reach the equator. We show that the reflection coefficient
depends on G Br , where Br is the strength of the radial magnetic field at the
equator, and G the conductance of the lower mantle there. With Br = 7e-4 T.,
torsional waves are completely absorbed when they hit the equator if G = 1.3e8
S. For larger or smaller G, reflection occurs. As G is increased above this
critical value, there is less attenuation and more angular momentum exchange.
Our finding dissociates efficient core-mantle coupling from strong ohmic
dissipation in the mantle.


title: A First-Order Electroweak Phase Transition from Varying Yukawas

abstract:
  We show that the dynamics responsible for the variation of the Yukawa
couplings of the Standard Model fermions generically leads to a very strong
first-order electroweak phase transition, assuming that the Yukawa couplings
are large and of order 1 before the electroweak phase transition and reach
their present value afterwards. There are good motivations to consider that the
flavour structure could emerge during electroweak symmetry breaking, for
example if the Froggatt-Nielsen field dynamics were linked to the Higgs field.
In this paper, we do not need to assume any particular theory of flavour and
show in a model-independent way how the nature of the electroweak phase
transition is completely changed when the Standard Model Yukawas vary at the
same time as the Higgs is acquiring its vacuum expectation value. The thermal
contribution of the fermions creates a barrier between the symmetric and broken
phase minima of the effective potential, leading to a first-order phase
transition. This offers new routes for generating the baryon asymmetry at the
electroweak scale, strongly tied to flavour models.


title: Deep Learning for Short-Term Traffic Flow Prediction

abstract:
  We develop a deep learning model to predict traffic flows. The main
contribution is development of an architecture that combines a linear model
that is fitted using $\ell_1$ regularization and a sequence of $\tanh$ layers.
The challenge of predicting traffic flows are the sharp nonlinearities due to
transitions between free flow, breakdown, recovery and congestion. We show that
deep learning architectures can capture these nonlinear spatio-temporal
effects. The first layer identifies spatio-temporal relations among predictors
and other layers model nonlinear relations. We illustrate our methodology on
road sensor data from Interstate I-55 and predict traffic flows during two
special events; a Chicago Bears football game and an extreme snowstorm event.
Both cases have sharp traffic flow regime changes, occurring very suddenly, and
we show how deep learning provides precise short term traffic flow predictions.


title: Tracking Human-like Natural Motion Using Deep Recurrent Neural Networks

abstract:
  Kinect skeleton tracker is able to achieve considerable human body tracking
performance in convenient and a low-cost manner. However, The tracker often
captures unnatural human poses such as discontinuous and vibrated motions when
self-occlusions occur. A majority of approaches tackle this problem by using
multiple Kinect sensors in a workspace. Combination of the measurements from
different sensors is then conducted in Kalman filter framework or optimization
problem is formulated for sensor fusion. However, these methods usually require
heuristics to measure reliability of measurements observed from each Kinect
sensor. In this paper, we developed a method to improve Kinect skeleton using
single Kinect sensor, in which supervised learning technique was employed to
correct unnatural tracking motions. Specifically, deep recurrent neural
networks were used for improving joint positions and velocities of Kinect
skeleton, and three methods were proposed to integrate the refined positions
and velocities for further enhancement. Moreover, we suggested a novel measure
to evaluate naturalness of captured motions. We evaluated the proposed approach
by comparison with the ground truth obtained using a commercial optical
maker-based motion capture system.


title:
$L^2$-error analysis of an isoparametric unfitted finite element method
  for elliptic interface problems

abstract:
  In the context of unfitted finite element discretizations the realization of
high order methods is challenging due to the fact that the geometry
approximation has to be sufficiently accurate. Recently a new unfitted finite
element method was introduced which achieves a high order approximation of the
geometry for domains which are implicitly described by smooth level set
functions. This method is based on a parametric mapping which transforms a
piecewise planar interface (or surface) reconstruction to a high order
approximation. In the paper [C. Lehrenfeld, A. Reusken, \emph{Analysis of a
High Order Finite Element Method for Elliptic Interface Problems}, arXiv
1602.02970, Accepted for publication in IMA J. Numer. Anal.] an a priori error
analysis of the method applied to an interface problem is presented. The
analysis reveals optimal order discretization error bounds in the $H^1$-norm.
In this paper we extend this analysis and derive optimal $L^2$-error bounds.


title: Noise-induced transitions in rugged energy landscapes

abstract:
  We consider the problem of an overdamped Brownian particle moving in
multiscale potential with N + 1 characteristic length scales: the macroscale
and N separated microscales. We show that the coarse-grained dynamics is given
by an overdamped Langevin equation with respect to the free energy and with a
space dependent diffusion tensor, the calculation of which requires the
solution of N fully coupled Poisson equations. We study in detail the structure
of the bifurcation diagram for one-dimensional problems and we show that the
multiscale structure in the potential leads to hysteresis effects and to
noise-induced transitions. Furthermore, we obtain an explicit formula for the
effective diffusion coefficient for a self-similar separable potential and we
investigate the limit of infinitely many small scales.


title:
Pressure effects on magnetic ground states in cobalt doped multiferroic
  Mn$_{1-x}$Co$_{x}$WO$_4$

abstract:
  Using ambient pressure x-ray and high pressure neutron diffraction, we
studied the pressure effect on structural and magnetic properties of
multiferroic Mn$_{1-x}$Co$_x$WO$_4$ single crystals ($x=0, 0.05, 0.135$ and
$0.17$), and compared it with the effects of doping. Both Co doping and
pressure stretch the Mn-Mn chain along the $c$~direction. At high doping level
($x=0.135$ and $0.17$), pressure and Co doping drive the system in a similar
way and induce a spin-flop transition for the $x=0.135$ compound. In contrast,
magnetic ground states at lower doping level ($x=0$ and $0.05$) are robust
against pressure but experience a pronounced change upon Co substitution. As Co
introduces both chemical pressure and magnetic anisotropy into the frustrated
magnetic system, our results suggest the magnetic anisotropy is the main
driving force for the Co induced phase transitions at low doping level, and
chemical pressure plays a more significant role at higher Co concentrations.


title: An adaptive preconditioner for steady incompressible flows

abstract:
  This paper describes an adaptive preconditioner for numerical continuation of
incompressible Navier--Stokes flows. The preconditioner maps the identity (no
preconditioner) to the Stokes preconditioner (preconditioning by Laplacian)
through a continuous parameter and is built on a first order Euler
time-discretization scheme. The preconditioner is tested onto two fluid
configurations: three-dimensional doubly diffusive convection and a reduced
model of shear flows. In the former case, Stokes preconditioning works but a
mixed preconditioner is preferred. In the latter case, the system of equation
is split and solved simultaneously using two different preconditioners, one of
which is parameter dependent. Due to the nature of these applications, this
preconditioner is expected to help a wide range of studies.


title: Universal critical behavior of the 2d Ising spin glass

abstract:
  We use finite size scaling to study Ising spin glasses in two spatial
dimensions. The issue of universality is addressed by comparing discrete and
continuous probability distributions for the quenched random couplings. The
sophisticated temperature dependency of the scaling fields is identified as the
major obstacle that has impeded a complete analysis. Once temperature is
relinquished in favor of the correlation length as the basic variable, we
obtain a reliable estimation of the anomalous dimension and of the thermal
critical exponent. Universality among binary and Gaussian couplings is
confirmed to a high numerical accuracy.


title:
Polarization leakage in epoch of reionization windows: II. Primary beam
  model and direction dependent calibration

abstract:
  Leakage of diffuse polarized emission into Stokes I caused by the polarized
primary beam of the instrument might mimic the spectral structure of the 21-cm
signal coming from the epoch of reionization (EoR) making their separation
difficult. Therefore, understanding polarimetric performance of the antenna is
crucial for a successful detection of the EoR signal. Here, we have calculated
the accuracy of the nominal model beam of LOFAR in predicting the leakage from
Stokes I to Q, U by comparing them with the corresponding leakage of compact
sources actually observed in the 3C295 field. We have found that the model beam
has errors of less than or equal to 10% on the predicted levels of leakage of
~1% within the field of view, i. e. if the leakage is taken out perfectly using
this model the leakage will reduce to $10^{-3}$ of the Stokes I flux. If
similar levels of accuracy can be obtained in removing leakage from Stokes Q, U
to I, we can say, based on the results of our previous paper, that the removal
of this leakage using this beam model would ensure that the leakage is well
below the expected EoR signal in almost the whole instrumental k-space of the
cylindrical power spectrum. We have also shown here that direction dependent
calibration can remove instrumentally polarized compact sources, given an
unpolarized sky model, very close to the local noise level.


title:
Algebraic K-theory and derived equivalences suggested by T-duality for
  torus orientifolds

abstract:
  We show that certain isomorphisms of (twisted) KR-groups that underlie
T-dualities of torus orientifold string theories have purely algebraic
analogues in terms of algebraic K-theory of real varieties and equivalences of
derived categories of (twisted) coherent sheaves. The most interesting
conclusion is a kind of Mukai duality in which the "dual abelian variety" to a
smooth projective genus-1 curve over R with no real points is (mildly)
noncommutative.


title:
Trend to equilibrium for reaction-diffusion systems arising from complex
  balanced chemical reaction networks

abstract:
  The quantitative convergence to equilibrium for reaction-diffusion systems
arising from complex balanced chemical reaction networks with mass action
kinetics is studied by using the so-called entropy method. In the first part of
the paper, by deriving explicitly the entropy dissipation, we show that for
complex balanced systems without boundary equilibria, each trajectory converges
exponentially fast to the unique complex balance equilibrium. Moreover, a
constructive proof is proposed to explicitly estimate the rate of convergence
in the special case of a cyclic reaction. In the second part of the paper,
complex balanced systems with boundary equilibria are considered. We
investigate two specific cases featuring two and three chemical substances
respectively. In these cases, the boundary equilibria are shown to be unstable
in some sense, so that exponential convergence to the unique strictly positive
equilibrium can also be proven.


title:
Collimation and asymmetry of the hot blast wave from the recurrent nova
  V745 Scorpii

abstract:
  The recurrent symbiotic nova V745 Sco exploded on 2014 February 6 and was
observed on February 22 and 23 by the Chandra X-ray Observatory Transmission
Grating Spectrometers. By that time the supersoft source phase had already
ended and Chandra spectra are consistent with emission from a hot, shock-heated
circumstellar medium with temperatures exceeding 10^7K. X-ray line profiles are
more sharply peaked than expected for a spherically-symmetric blast wave, with
a full width at zero intensity of approximately 2400 km/s, a full width at half
maximum of 1200 +/- 30 km/s and an average net blueshift of 165 +/- 10 km/s.
The red wings of lines are increasingly absorbed toward longer wavelengths by
material within the remnant. We conclude that the blast wave was sculpted by an
aspherical circumstellar medium in which an equatorial density enhancement
plays a role, as in earlier symbiotic nova explosions. Expansion of the
dominant X-ray emitting material is aligned close to the plane of the sky and
most consistent with an orbit seen close to face-on. Comparison of an
analytical blast wave model with the X-ray spectra, Swift observations and
near-infrared line widths indicates the explosion energy was approximately
10^43 erg, and confirms an ejected mass of approximately 10^-7 Msun. The total
mass lost is an order of magnitude lower than the accreted mass required to
have initiated the explosion, indicating the white dwarf is gaining mass and is
a supernova Type 1a progenitor candidate.


title: An Assessment of Sunspot Number Data Composites over 1845-2014

abstract:
  New sunspot data composites, some of which are radically different in the
character of their long-term variation, are evaluated over the interval
1845-2014. The method commonly used to calibrate historic sunspot data,
relative to modern-day data, is "daisy-chaining", whereby calibration is passed
from one data subset to the neighbouring one, usually using regressions of the
data subsets for the intervals of their overlap. Recent studies have
illustrated serious pitfalls in these regressions and the resulting errors can
be compounded by their repeated use as the data sequence is extended back in
time. Hence the recent composite data series by Usoskin et al. (2016),
$R_{UEA}$, is a very important advance because it avoids regressions,
daisy-chaining and other common, but invalid, assumptions: this is achieved by
comparing the statistics of "active day" fractions to those for a single
reference dataset. We study six sunspot data series including $R_{UEA}$ and the
new "backbone" data series $R_{BB}$, recently generated by Svalgaard and
Schatten (2016) by employing both regression and daisy-chaining. We show that
all six can be used with a continuity model to reproduce the main features of
the open solar flux variation for 1845-2014, as reconstructed from geomagnetic
activity data. However, some differences can be identified that are consistent
with tests using a basket of other proxies for solar magnetic fields. Using
data from a variety of sunspot observers, we illustrate problems with the
method employed in $R_{BB}$ which cause it to increasingly overestimate sunspot
numbers going back in time and we recommend using $R_{UEA}$ because it employs
more robust procedures that avoid such problems.


title:
Unsupervised single-particle deep clustering via statistical manifold
  learning

abstract:
  Motivation: Structural heterogeneity in single-particle cryo-electron
microscopy (cryo-EM) data represents a major challenge for high-resolution
structure determination. Unsupervised classification may serve as the first
step in the assessment of structural heterogeneity. Traditional algorithms for
unsupervised classification, such as K-means clustering and maximum likelihood
optimization, may classify images into wrong classes with decreasing
signal-to-noise-ratio (SNR) in the image data, yet demand increased cost in
computation. Overcoming these limitations requires further development on
clustering algorithms for high-performance cryo-EM data analysis. Results: Here
we introduce a statistical manifold learning algorithm for unsupervised
single-particle deep clustering. We show that statistical manifold learning
improves classification accuracy by about 40% in the absence of input
references for lower SNR data. Applications to several experimental datasets
suggest that our deep clustering approach can detect subtle structural
difference among classes. Through code optimization over the Intel
high-performance computing (HPC) processors, our software implementation can
generate thousands of reference-free class averages within several hours from
hundreds of thousands of single-particle cryo-EM images, which allows
significant improvement in ab initio 3D reconstruction resolution and quality.
Our approach has been successfully applied in several structural determination
projects. We expect that it provides a powerful computational tool in analyzing
highly heterogeneous structural data and assisting in computational
purification of single-particle datasets for high-resolution reconstruction.


title:
Dielectrics in a time-dependent electric field: a real-time approach
  based on density-polarization functional theory

abstract:
  In the presence of a (time-dependent) macroscopic electric field the electron
dynamics of dielectrics cannot be described by the time-dependent density only.
We present a real-time formalism that has the density and the macroscopic
polarization P as key quantities. We show that a simple local function of P
already captures long-range correlation in linear and nonlinear optical
response functions. Specifically, after detailing the numerical implementation,
we examine the optical absorption, the second- and third-harmonic generation of
bulk Si, GaAs, AlAs and CdTe at different level of approximation. We highlight
links with ultranonlocal exchange-correlation functional approximations
proposed within linear response time-dependent density functional theory
framework.


title: Worst-case multi-objective error estimation and adaptivity

abstract:
  This paper introduces a new computational methodology for determining
a-posteriori multi-objective error estimates for finite-element approximations,
and for constructing corresponding (quasi-)optimal adaptive refinements of
finite-element spaces. As opposed to the classical goal-oriented approaches,
which consider only a single objective functional, the presented methodology
applies to general closed convex subsets of the dual space and constructs a
worst-case error estimate of the finite-element approximation error. This
worst-case multi-objective error estimate conforms to a dual-weighted residual,
in which the dual solution is associated with an approximate supporting
functional of the objective set at the approximation error. We regard both
standard approximation errors and data-incompatibility errors associated with
incompatibility of boundary data with the trace of the finite-element space.
Numerical experiments are presented to demonstrate the efficacy of applying the
proposed worst-case multi-objective error in adaptive refinement procedures.


title: Untangling knots via reaction-diffusion dynamics of vortex strings

abstract:
  We introduce and illustrate a new approach to the unknotting problem via the
dynamics of vortex strings in a nonlinear partial differential equation of
reaction-diffusion type. To untangle a given knot, a Biot-Savart construction
is used to initialize the knot as a vortex string in the FitzHugh-Nagumo
equation. Remarkably, we find that the subsequent evolution preserves the
topology of the knot and can untangle an unknot into a circle. Illustrative
test case examples are presented, including the untangling of a hard unknot
known as the culprit. Our approach to the unknotting problem has two novel
features, in that it applies field theory rather than particle mechanics and
uses reaction-diffusion dynamics in place of energy minimization.

categories: nlin.PS cond-mat.soft hep-th math-ph math.GT math.MP


title:
Radio Flaring from the T6 Dwarf WISEPC J112254.73+255021.5 with A
  Possible Ultra-short Periodicity

abstract:
  We present new results from a continuing 5 GHz search for flaring radio
emission from a sample of L and T brown dwarfs, conducted with the 305-m
Arecibo radio telescope. In addition to the previously reported flaring from
the T6.5-dwarf 2MASS J10475385+212423, we have detected and confirmed
circularly polarized flares from another T6-dwarf, WISEPC J112254.73+255021.5.
Although the flares are sporadic, they appear to occur at a stable period of
0.288 hours. Given the current constraints, periods equal to its second and
third subharmonic cannot be ruled out. The stability of this period over the
8-month timespan of observations indicates that, if real, it likely reflects
the star's rapid rotation. If confirmed, any of the three inferred
periodicities would be much shorter than the shortest, 1.41-hour rotation
period of a brown dwarf measured so far. This finding would place a new
observational constraint on the angular momentum evolution and rotational
stability of substellar objects. The detection of radio emission from the sixth
~1000 K dwarf further demonstrates that the coolest brown dwarfs and, possibly,
young giant planets, can be efficiently investigated using radio observations
at centimeter wavelengths as a tool.


title: Dynamics of a Probable Earth-mass Planet in GJ 832 System

abstract:
  Stability of planetary orbits around the GJ 832 star system, which contains
inner (GJ 832c) and outer (GJ 832b) planets, is investigated numerically and a
detailed phase-space analysis is performed. A special emphasis is given to the
existence of stable orbits for a planet less than 15M$_\oplus$ which is
injected between the inner and outer planets. Thus, numerical simulations are
performed for three and four bodies in elliptical orbits (or circular for
special cases) by using a large number of initial conditions that cover the
selected phase-spaces of the planet's orbital parameters. The results presented
in the phase-space maps for GJ 832c indicate the least deviation of
eccentricity from its nominal value, which is then used to determine its
inclination regime relative to the star-outer planet plane. Also, the injected
planet displays stable orbital configurations for at least one billion years.
Then, the radial velocity curves based on the signature from the Keplerian
motion are generated for the injected planets with masses 1M$_\oplus$ to
15M$_\oplus$ in order to estimate their semimajor axes and mass-limit. The
synthetic RV signal suggests that an additional planet of mass $\le$
15M$_\oplus$ with dynamically stable configuration may be residing between 0.25
- 2.0 AU from the star. We have provided an estimated number of RV observations
for the additional planet that is required for further observational
verification.


title: How well does CO emission measure the H$_2$ mass of MCs?

abstract:
  We present numerical simulations of molecular clouds (MCs) with
self-consistent CO gas-phase and isotope chemistry in various environments. The
simulations are post-processed with a line radiative transfer code to obtain
$^{12}$CO and $^{13}$CO emission maps for the $J=1\rightarrow0$ rotational
transition. The emission maps are analysed with commonly used observational
methods, i.e. the $^{13}$CO column density measurement, the virial mass
estimate and the so-called $X_{\textrm{CO}}$ (also CO-to-H$_2$) conversion
factor, and then the inferred quantities (i.e. mass and column density) are
compared to the physical values. We generally find that most methods examined
here recover the CO-emitting H$_{2}$ gas mass of MCs within a factor of two
uncertainty if the metallicity is not too low. The exception is the $^{13}$CO
column density method. It is affected by chemical and optical depth issues, and
it measures both the true H$_{2}$ column density distribution and the molecular
mass poorly. The virial mass estimate seems to work the best in the considered
metallicity and radiation field strength range, even when the overall virial
parameter of the cloud is above the equilibrium value. This is explained by a
systematically lower virial parameter (i.e. closer to equilibrium) in the
CO-emitting regions; in CO emission, clouds might seem (sub-)virial, even when,
in fact, they are expanding or being dispersed. A single CO-to-H$_{2}$
conversion factor appears to be a robust choice over relatively wide ranges of
cloud conditions, unless the metallicity is low. The methods which try to take
the metallicity dependence of the conversion factor into account tend to
systematically overestimate the true cloud masses.


title: Geometric optics for surface waves in nonlinear elasticity

abstract:
  This work is devoted to the analysis of high frequency solutions to the
equations of nonlinear elasticity in a half-space. We consider surface waves
(or more precisely, Rayleigh waves) arising in the general class of isotropic
hyperelastic models, which includes in particular the Saint Venant-Kirchhoff
system. Work has been done by a number of authors since the 1980s on the
formulation and well-posedness of a nonlinear evolution equation whose (exact)
solution gives the leading term of an \emph{approximate} Rayleigh wave solution
to the underlying elasticity equations. This evolution equation, which we refer
to as "the amplitude equation", is an integrodifferential equation of nonlocal
Burgers type. We begin by reviewing and providing some extensions of the theory
of the amplitude equation. The remainder of the paper is devoted to a rigorous
proof in 2D that exact, highly oscillatory, Rayleigh wave solutions $u^\eps$ to
the nonlinear elasticity equations exist on a fixed time interval independent
of the wavelength $\eps$, and that the approximate Rayleigh wave solution
provided by the analysis of the amplitude equation is indeed close in a precise
sense to $u^\eps$ on a time interval independent of $\eps$. The paper focuses
mainly on the case of Rayleigh waves that are \emph{pulses}, which have
profiles with continuous Fourier spectrum, but our method applies equally well
to the case of wavetrains, whose Fourier spectrum is discrete.


title: Kaon regeneration

abstract:
  We have performed the calculation of kaon regeneration based on the exact
solution of equations of motion. The result differs radically from the previous
one.


title:
Experimental observation of strong coupling effects on the dispersion of
  dust acoustic waves in a plasma

abstract:
  The dispersion properties of low frequency dust acoustic waves in the strong
coupling regime are investigated experimentally in an argon plasma embedded
with a mixture of kaolin and $MnO_2$ dust particles. The neutral pressure is
varied over a wide range to change the collisional properties of the dusty
plasma. In the low collisional regime the turnover of the dispersion curve at
higher wave numbers and the resultant region of $\partial\omega/\partial k < 0$
are identified as signatures of dust-dust correlations. In the high collisional
regime dust neutral collisions produce a similar effect and prevent an
unambiguous identification of strong coupling effects.


title: Scalefree hardness of average-case Euclidean TSP approximation

abstract:
  We show that if P$\neq$NP, then a wide class of TSP heuristics fail to
approximate the length of the TSP to asymptotic optimality, even for random
Euclidean instances. Previously, this result was not even known for any
heuristics (greedy, etc) used in practice. As an application, we show that when
using a heuristic from this class, a natural class of branch-and-bound
algorithms takes exponential time to find an optimal tour (again, even on a
random point-set), regardless of the particular branching strategy or
lower-bound algorithm used.


title: Resistive Plate Chamber Digitization in a Hadronic Shower Environment

abstract:
  The CALICE Semi-Digital Hadron Calorimeter (SDHCAL) technological prototype
is a sampling calorimeter using Glass Resistive Plate Chamber detectors with a
three-threshold readout as the active medium. This technology is one of the two
options proposed for the hadron calorimeter of the International Large Detector
for the International Linear Collider. The prototype was exposed to beams of
muons, electrons and pions of different energies at the CERN Super Proton
Synchrotron. To be able to study the performance of such a calorimeter in
future experiments it is important to ensure reliable simulation of its
response. In this paper we present our prototype simulation performed with
GEANT4 and the digitization procedure achieved with an algorithm called
SimDigital. A detailed description of this algorithm is given and the methods
to determinate its parameters using muon tracks and electromagnetic showers are
explained. The comparison with hadronic shower data shows a good agreement up
to 50 GeV. Discrepancies are observed at higher energies. The reasons for these
differences are investigated.


title:
Single crystal growth from separated educts and its application to
  lithium transition-metal oxides

abstract:
  Thorough mixing of the starting materials is the first step of a crystal
growth procedure. This holds true for almost any standard technique, whereas
the intentional separation of educts is considered to be restricted to a very
limited number of cases. A noticeable exception is the crystal growth in gels
that allows for a better control of the nucleation by limiting the diffusion.
The successful application of this principle to open systems, however, has
remained elusive. Here we show that single crystals of {\alpha}-Li2IrO3 can be
grown from separated educts in an open crucible in air. Elemental lithium and
iridium are oxidized and transported over a distance of typically one
centimeter in an isothermal process. Single crystals grow from an exposed
condensation point placed in between the educts. The method has also been
applied to the growth of Li2RuO3, Li2PtO3 and {\beta}-Li2IrO3 and a successful
use for various other materials is anticipated.


title:
Collider Constraints and Prospects of a Scalar Singlet Extension to
  Higgs Portal Dark Matter

abstract:
  This work considers an extension of the Standard Model (SM) Higgs sector by a
real, scalar singlet field, including applicability to a dark matter (DM) model
with the addition of a Yukawa coupling to a Dirac fermion. The collider
signatures and constraints on the mixed two-Higgs scenario are determined,
including limits from Higgs production signals and exclusion searches, as well
as constraints arising from the Higgs total and invisible widths. As there is
overwhelming Higgs data which is consistent with a SM scenario, the case in
which an additional scalar has evaded detection is further explored in the
context of Higgs precision measurement. The discovery reach and prospective
signatures of the model at a proposed linear collider are investigated, with
particular focus on the Higgs triple coupling, and di-Higgs production
processes.


title:
Inferring $R_0$ in emerging epidemics - the effect of common population
  structure is small

abstract:
  When controlling an emerging outbreak of an infectious disease it is
essential to know the key epidemiological parameters, such as the basic
reproduction number $R_0$ and the control effort required to prevent a large
outbreak. These parameters are estimated from the observed incidence of new
cases and information about the infectious contact structures of the population
in which the disease spreads. However, the relevant infectious contact
structures for new, emerging infections are often unknown or hard to obtain.
Here we show that for many common true underlying heterogeneous contact
structures, the simplification to neglect such structures and instead assume
that all contacts are made homogeneously in the whole population, results in
conservative estimates for $R_0$ and the required control effort. This means
that robust control policies can be planned during the early stages of an
outbreak, using such conservative estimates of the required control effort.


title: Momentum Maps and Stochastic Clebsch Action Principles

abstract:
  We derive stochastic differential equations whose solutions follow the flow
of a stochastic nonlinear Lie algebra operation on a configuration manifold.
For this purpose, we develop a stochastic Clebsch action principle, in which
the noise couples to the phase space variables through a momentum map. This
special coupling simplifies the structure of the resulting stochastic Hamilton
equations for the momentum map. In particular, these stochastic Hamilton
equations collectivize for Hamiltonians that depend only on the momentum map
variable. The Stratonovich equations are derived from the Clebsch variational
principle and then converted into It\^o form. In comparing the Stratonovich and
It\^o forms of the stochastic dynamical equations governing the components of
the momentum map, we find that the It\^o contraction term turns out to be a
double Poisson bracket. Finally, we present the stochastic Hamiltonian
formulation of the collectivized momentum map dynamics and derive the
corresponding Kolmogorov forward and backward equations.


title:
Comments on "Thermic and Caloric Equations of State with Small Number of
  Parameters"

abstract:
  It is shown that the potential of Keesom which depends on temperature cannot
be used for calculate the second virial coefficient of polar molecules and the
formulae for second virial coefficient of [2] have no molecular statistical
mechanical base for water and carbon dioxide. The contradictions and errors of
[2] are discussed.


title: Bottom ${\bf (70,1^-)}$ baryon multiplet

abstract:
  The masses of negative parity $(70,1^-)$ bottom nonstrange baryons are
calculated in the relativistic quark model. The relativistic three-quark
equations of the $(70,1^-)$ bottom baryon multiplet are derived in the
framework of the dispersion relation technique. The approximate solutions of
these equations using the method based on the extraction of leading
singularities of the amplitude are obtained. The masses of 21 baryons are
predicted.


title: Reversed Dickson polynomials of the fourth kind over finite fields

abstract:
  In this paper, we obtain several results on the permutational behavior of the
reversed Dickson polynomial $D_{n,3}(1,x)$ of the fourth kind over the finite
field ${\mathbb F}_{q}$. Particularly, we present the explicit evaluation of
the first moment $\sum_{a\in {\mathbb F}_{q}}D_{n,3}(1,a)$.


title: Accessing accurate documents by mining auxiliary document information

abstract:
  Earlier techniques of text mining included algorithms like k-means, Naive
Bayes, SVM which classify and cluster the text document for mining relevant
information about the documents. The need for improving the mining techniques
has us searching for techniques using the available algorithms. This paper
proposes one technique which uses the auxiliary information that is present
inside the text documents to improve the mining. This auxiliary information can
be a description to the content. This information can be either useful or
completely useless for mining. The user should assess the worth of the
auxiliary information before considering this technique for text mining. In
this paper, a combination of classical clustering algorithms is used to mine
the datasets. The algorithm runs in two stages which carry out mining at
different levels of abstraction. The clustered documents would then be
classified based on the necessary groups. The proposed technique is aimed at
improved results of document clustering.


title:
Dark matter scattering on electrons: Accurate calculations of atomic
  excitations and implications for the DAMA signal

abstract:
  We revisit the WIMP-type dark matter scattering on electrons that results in
atomic ionization, and can manifest itself in a variety of existing
direct-detection experiments. Unlike the WIMP-nucleon scattering, where current
experiments probe typical interaction strengths much smaller than the Fermi
constant, the scattering on electrons requires a much stronger interaction to
be detectable, which in turn requires new light force carriers. We account for
such new forces explicitly, by introducing a mediator particle with scalar or
vector couplings to dark matter and to electrons. We then perform state of the
art numerical calculations of atomic ionization relevant to the existing
experiments. Our goals are to consistently take into account the atomic physics
aspect of the problem (e.g., the relativistic effects, which can be quite
significant), and to scan the parameter space: the dark matter mass, the
mediator mass, and the effective coupling strength, to see if there is any part
of the parameter space that could potentially explain the DAMA modulation
signal. While we find that the modulation fraction of all events with energy
deposition above 2 keV in NaI can be quite significant, reaching ~50%, the
relevant parts of the parameter space are excluded by the XENON10 and XENON100
experiments.

categories: hep-ph astro-ph.CO hep-ex physics.atom-ph


title:
A generalized traction integral equation for Stokes flow, with
  applications to near-wall particle mobility and viscous erosion

abstract:
  A double-layer integral equation for the surface tractions on a body moving
in a viscous fluid is derived which allows for the incorporation of a
background flow and/or the presence of a plane wall. The Lorentz reciprocal
theorem is used to link the surface tractions on the body to integrals
involving the background velocity and stress fields on an imaginary bounding
sphere (or hemisphere for wall-bounded flows). The derivation requires the
velocity and stress fields associated with numerous fundamental singularity
solutions which we provide for free-space and wall-bounded domains. Two sample
applications of the method are discussed: we study the tractions on an
ellipsoid moving near a plane wall, which provides a more detailed
understanding of the well-studied glancing and reversing trajectories in the
context of particle sedimentation, and the erosion of bodies by a viscous flow,
in which the surface is ablated at a rate proportional to the local viscous
shear stress. Simulations and analytical estimates suggest that a spherical
body in a uniform flow first reduces nearly but not exactly to the drag
minimizing profile and then vanishes in finite time. The shape dynamics of an
eroding body in a shear flow and near a wall are also investigated. Stagnation
points on the body surface lead generically to the formation of cusps, whose
number depends on the flow configuration and/or the presence of nearby
boundaries.

categories: physics.flu-dyn cond-mat.soft physics.bio-ph physics.comp-ph physics.geo-ph


title:
Commutation principles in Euclidean Jordan algebras and normal
  decomposition systems

abstract:
  The commutation principle of Ramirez, Seeger, and Sossa
\cite{ramirez-seeger-sossa} proved in the setting of Euclidean Jordan algebras
says that when the sum of a Fr\'{e}chet differentiable function $\Theta(x)$ and
a spectral function $F(x)$ is minimized over a spectral set $\Omega$, any local
minimizer $a$ operator commutes with the Fr\'{e}chet derivative
$\Theta^{\prime}(a)$. In this paper, we extend this result to sets and
functions which are (just) invariant under algebra automorphisms. We also
consider a similar principle in the setting of normal decomposition systems.


title: A Network-based End-to-End Trainable Task-oriented Dialogue System

abstract:
  Teaching machines to accomplish tasks by conversing naturally with humans is
challenging. Currently, developing task-oriented dialogue systems requires
creating multiple components and typically this involves either a large amount
of handcrafting, or acquiring costly labelled datasets to solve a statistical
learning problem for each component. In this work we introduce a neural
network-based text-in, text-out end-to-end trainable goal-oriented dialogue
system along with a new way of collecting dialogue data based on a novel
pipe-lined Wizard-of-Oz framework. This approach allows us to develop dialogue
systems easily and without making too many assumptions about the task at hand.
The results show that the model can converse with human subjects naturally
whilst helping them to accomplish tasks in a restaurant search domain.


title:
Torsion points and height jumping in higher-dimensional families of
  abelian varieties

abstract:
  In 1983 Silverman and Tate showed that the set of points in a 1-dimensional
family of abelian varieties where a section of infinite order has `small
height' is finite. We conjecture a generalisation to higher-dimensional
families, where we replace `finite' by `not Zariski dense'. We show that this
conjecture would imply the Uniform Boundedness Conjecture for torsion points on
abelian varieties. We then prove a few special cases of this new conjecture.


title: The analytic class number formula for $1$-dimensional affine schemes

abstract:
  We derive an analytic class number formula valid for an order in a product of
$S$-integers in global fields, or equivalently for reduced finite-type affine
schemes of pure dimension $1$ over $\mathbb{Z}$.


title:
Novel magnetism on a honeycomb lattice in a-RuCl3 studied by muon spin
  rotation

abstract:
  Muon spin rotation measurements have been performed on a powder sample of
a-RuCl3, a layered material which previously has been proposed to be a quantum
magnet on a honeycomb lattice close to a quantum spin liquid ground state. Our
data reveal two distinct phase transitions at 11 K and 14 K which we interpret
as originating from the onset of three-dimensional order and in-plane magnetic
order, respectively. We identify, with the help of density functional theory
calculations, likely muon stopping sites and combine these with dipolar field
calculations to show that the two measured muon rotation frequencies are
consistent with two inequivalent muon sites within a zig-zag antiferromagnetic
structure proposed previously.


title:
Diverse Features of the Multi-wavelength Afterglows of Gamma-ray Bursts:
  Natural or Special?

abstract:
  The detection of optical re-brightenings and X-ray plateaus in the afterglows
of gamma-ray bursts (GRBs) challenges the generic external shock model.
Recently, we have developed a numerical method to calculate the dynamic of the
system consisting of a forward shock and a reverse shock. Here, we briefly
review the applications of this method in the afterglow theory. By relating
these diverse features to the central engines of GRBs, we find that the steep
optical re-brightenings would be caused by the fall-back accretion of black
holes, while the shallow optical re-brightenings are the consequence of the
injection of the electron-positron-pair wind from the central magnetar. These
studies provide useful ways to probe the characteristics of GRB central
engines.


title: Cooperative Wireless Backhauling

abstract:
  We consider wireless backhauling for a scenario where two small-cell base
stations (SC-BSs) employ the same time and frequency resources for offloading
their data to a common macro-cell base station (MC-BS). The two SC-BSs allocate
a part of the shared resource to exchange data in order to be able to cooperate
to boost the backhaul capacity. For this scenario, we develop the optimal
transmission strategy which, based on the channel state information, determines
whether the SC-BSs should exchange data and cooperate or transmit their data
independently to the MC-BS. Our numerical results demonstrate the superiority
of the proposed cooperative~wireless backhauling protocol compared to existing
protocols in the literature.


title:
Local convergence analysis of Newton's method for solving strongly
  regular generalized equations

abstract:
  In this paper we study Newton's method for solving generalized equations in
Banach spaces. We show that under strong regularity of the generalized
equation, the method is locally convergent to a solution with
superlinear/quadratic rate. The presented analysis is based on Banach
Perturbation Lemma for generalized equation and the classical Lipschitz
condition on the derivative is relaxed by using a general majorant function,
which enables obtaining the optimal convergence radius, uniqueness of solution
as well as unifies earlier results pertaining to Newton's method theory.


title:
Kantorovich's theorem on Newton's method for solving strongly regular
  generalized equation

abstract:
  In this paper we consider the Newton's method for solving the generalized
equation of the form $ f(x) +F(x) \ni 0, $ where $f:{\Omega}\to Y$ is a
continuously differentiable mapping, $X$ and $Y$ are Banach spaces,
$\Omega\subseteq X$ an open set and $F:X \rightrightarrows Y$ be a set-valued
mapping with nonempty closed graph. We show that, under strong regularity of
the generalized equation, concept introduced by S.M.Robinson in [27], and
starting point satisfying the Kantorovich's assumptions, the Newton's method is
quadratically convergent to a solution, which is unique in a suitable
neighborhood of the starting point. The analysis presented based on Banach
Perturbation Lemma for generalized equation and the majorant technique, allow
to unify some results pertaining the Newton's method theory.


title: Community structure and interaction dynamics through the lens of quotes

abstract:
  This is the first work investigating community structure and interaction
dynamics through the lens of quotes in online discussion forums. We examine
four forums of different size, language, and topic. Quote usage, which is
surprisingly consistent over time and users, appears to have an important role
in aiding intra-thread navigation, and uncovers a hidden "social" structure in
communities otherwise lacking all trappings (from friends and followers to
reputations) of today's social networks.


title: Level structures on abelian varieties and Vojta's conjecture

abstract:
  Assuming Vojta's conjecture, and building on recent work of the authors, we
prove that, for a fixed number field $K$ and positive integer $g$, there is an
integer $m_0$ such that for any $m > m_0$ there is no principally polarized
abelian variety $A/K$ of dimension $g$ with full level-$m$ structure. To this
end, we develop a version of Vojta's conjecture for Deligne-Mumford stacks,
which we deduce from Vojta's conjecture for schemes.


title:
Classical Electromagnetic Fields from Quantum Sources in Heavy-Ion
  Collisions

abstract:
  Electromagnetic fields are generated in high energy nuclear collisions by
spectator valence protons. These fields are traditionally computed by
integrating the Maxwell equations with point sources. One might expect that
such an approach is valid at distances much larger than the proton size and
thus such a classical approach should work well for almost the entire
interaction region in the case of heavy nuclei. We argue that, in fact, the
contrary is true: due to the quantum diffusion of the proton wave function, the
classical approximation breaks down at distances of the order of the system
size. We compute the electromagnetic field created by a charged particle
described initially as a Gaussian wave packet of width 1 fm and evolving in
vacuum according to the Klein-Gordon equation. We completely neglect the medium
effects. We show that the dynamics, magnitude and even sign of the
electromagnetic field created by classical and quantum sources are different.


title: CNN-RNN: A Unified Framework for Multi-label Image Classification

abstract:
  While deep convolutional neural networks (CNNs) have shown a great success in
single-label image classification, it is important to note that real world
images generally contain multiple labels, which could correspond to different
objects, scenes, actions and attributes in an image. Traditional approaches to
multi-label image classification learn independent classifiers for each
category and employ ranking or thresholding on the classification results.
These techniques, although working well, fail to explicitly exploit the label
dependencies in an image. In this paper, we utilize recurrent neural networks
(RNNs) to address this problem. Combined with CNNs, the proposed CNN-RNN
framework learns a joint image-label embedding to characterize the semantic
label dependency as well as the image-label relevance, and it can be trained
end-to-end from scratch to integrate both information in a unified framework.
Experimental results on public benchmark datasets demonstrate that the proposed
architecture achieves better performance than the state-of-the-art multi-label
classification model


title: Learning Temporal Regularity in Video Sequences

abstract:
  Perceiving meaningful activities in a long video sequence is a challenging
problem due to ambiguous definition of 'meaningfulness' as well as clutters in
the scene. We approach this problem by learning a generative model for regular
motion patterns, termed as regularity, using multiple sources with very limited
supervision. Specifically, we propose two methods that are built upon the
autoencoders for their ability to work with little to no supervision. We first
leverage the conventional handcrafted spatio-temporal local features and learn
a fully connected autoencoder on them. Second, we build a fully convolutional
feed-forward autoencoder to learn both the local features and the classifiers
as an end-to-end learning framework. Our model can capture the regularities
from multiple datasets. We evaluate our methods in both qualitative and
quantitative ways - showing the learned regularity of videos in various aspects
and demonstrating competitive performance on anomaly detection datasets as an
application.


title:
Proof-relevant $\pi$-calculus: a constructive account of concurrency and
  causality

abstract:
  We present a formalisation in Agda of the theory of concurrent transitions,
residuation, and causal equivalence of traces for the pi-calculus. Our
formalisation employs de Bruijn indices and dependently-typed syntax, and
aligns the "proved transitions" proposed by Boudol and Castellani in the
context of CCS with the proof terms naturally present in Agda's representation
of the labelled transition relation. Our main contributions are proofs of the
"diamond lemma" for the residuals of concurrent transitions and a formal
definition of equivalence of traces up to permutation of transitions.
  In the pi-calculus transitions represent propagating binders whenever their
actions involve bound names. To accommodate these cases, we require a more
general diamond lemma where the target states of equivalent traces are no
longer identical, but are related by a braiding that rewires the bound and free
names to reflect the particular interleaving of events involving binders. Our
approach may be useful for modelling concurrency in other languages where
transitions carry metadata sensitive to particular interleavings, such as
dynamically allocated memory addresses.


title:
Epsilon-Near-Zero Photonics Wires for Mid-Infrared Optical Lumped
  Circuitry

abstract:
  There has been recent interest in the development of optical analogues of
lumped element circuitry, where optical elements act as effective optical
inductors, capacitors, and resistors. Such optical circuitry requires the
photonic equivalent of electrical wires, structures able carry optical
frequency signals to and from the lumped circuit elements while simultaneously
maintaining signal carrier wavelengths much larger than the size of the lumped
elements. Here we demonstrate the design, fabrication, and characterization of
hybrid metal/doped-semiconductor 'photonic wires' operating at optical
frequencies with effective indices of propagation near-zero. Our samples are
characterized by polarization and angle-dependent FTIR spectroscopy and modeled
by finite element methods and rigorous coupled wave analysis. We demonstrate
coupling to such photonic wires from free space, and show the effective
wavelength of the excited mode to be approximately an order of magnitude larger
than the free-space wavelength of our light. The operational length of the
photonic wires approaches twice the free space wavelength, significantly longer
than what is achievable with bulk epsilon near zero materials. The novel
architecture utilized in our hybrid waveguides allows for significant design
flexibility by control of the semiconductor material's optical properties and
the sample geometry. In addition, by utilizing a semiconductor-based
architecture, our photonic wires can be designed to monolithically integrate
the optical equivalents of capacitive, inductive, and resistive lumped circuit
elements, as well optoelectronic sources and detectors. As such, the
demonstrated photonic wires have the potential to provide a key component, and
a realistic framework, for the development of optical circuitry.


title:
Ionized outflows in luminous type 2 AGNs at z<0.6: no evidence for
  significant impact on the host galaxies

abstract:
  We investigate the presence of extended ionized outflows in 18 luminous type
2 AGNs (11 quasars and 7 high luminosity Seyfert 2s) at 0.3<z<0.6 based on
VLT-FORS2 spectroscopy. We infer typical lower limits on the radial sizes of
the outflows R>=severalx100 pc and upper limits R<1-2 kpc. Our results are
inconsistent with related studies which suggest that large scale R~several-15
kpc are ubiquitous in QSO2. We study the possible causes of discrepancy and
propose that seeing smearing is the cause of the large inferred sizes. The
implications in our understanding of the feedback phenomenon are important
since the mass M (through the density), mass injection M(dot) and energy
injection rates E(dot) of the outflows become highly uncertain. One conclusion
seems unavoidable: M, M(dot), E(dot) are modest or low compared with previous
estimations. No evidence is found supporting that typical outflows can affect
the interstellar medium of the host galaxies accross spatial scales >~1-2 kpc.


title: Static spherically symmetric wormholes with isotropic pressure

abstract:
  In this paper we study static spherically symmetric wormhole solutions
sustained by matter sources with isotropic pressure. We show that such
spherical wormholes do not exist in the framework of zero-tidal-force
wormholes. On the other hand, it is shown that for the often used power-law
shape function there is no spherically symmetric traversable wormholes
sustained by sources with a linear equation of state $p=\omega \rho$ for the
isotropic pressure, independently of the form of the redshift function
$\phi(r)$. We consider a solution obtained by Tolman at 1939 for describing
static spheres of isotropic fluids, and show that it also may describe wormhole
spacetimes with a power-law redshift function, which leads to a polynomial
shape function, generalizing a power-law shape function, and inducing a solid
angle deficit.


title:
Competition Between Regulation-Providing and Fixed-Power Charging
  Stations for Electric Vehicles

abstract:
  This paper models a non-cooperative game between two EV charging stations.
One is a fixed-power charging station purchasing electricity from the grid at
wholesale price and reselling the energy to EV owners at a higher retail price;
the other is regulation-providing and varies the recharging power level of its
clients to provide regulation services to the grid, so its profit comes from
both EV owners (who buy energy) and the grid (which pays for regulation
services). Users are reluctant to charging power variations and prefer shorter
overall charging times, hence regulation-providing charging has to be cheaper
than fixed-power charging.
  We analyze the competition among those charging providers, and examine the
performance at the equilibrium in terms of user welfare, station revenue and
electricity prices. As expected, competing stations provide users with lower
charging prices than when both charging solutions are offered by a monopolistic
provider. Moreover, while competition benefits users, it also benefits the grid
in that the amount of regulation services increases significantly with respect
to the monopolistic case.


title: Compact Sets in the Free Topology

abstract:
  Subsets of the set of $g$-tuples of matrices that are closed with respect to
direct sums and compact in the free topology are characterized. They are, in a
dilation theoretic sense, contained in the hull of a single point.


title:
Electronic Structure Descriptor for Discovery of Narrow-Band
  Red-Emitting Phosphors

abstract:
  Narrow-band red-emitting phosphors are a critical component in
phosphor-converted light-emitting diodes for highly efficient
illumination-grade lighting. In this work, we report the discovery of a
quantitative descriptor for narrow-band Eu2+-activated emission identified
through a comparison of the electronic structure of known narrow-band and
broad-band phosphors. We find that a narrow emission bandwidth is characterized
by a large splitting of more than 0.1 eV between the two highest Eu2+ 4f7
bands. By incorporating this descriptor in a high throughput first principles
screening of 2,259 nitride compounds, we identify five promising new nitride
hosts for Eu2+-activated red-emitting phosphors that are predicted to exhibit
good chemical stability, thermal quenching resistance and quantum efficiency,
as well as narrow-band emission. Our findings provide important insights into
the emission characteristics of rare-earth activators in phosphor hosts, and a
general strategy to the discovery of phosphors with a desired emission peak and
bandwidth.


title: Simulations on the combinatorial structure of D-optimal designs

abstract:
  In this work we present the results of several simulations on main-effect
factorial designs. The goal of such simulations is to investigate the
connections between the $D$-optimality of a design and its geometrical
structure. By means of a combinatorial object, namely the circuit basis of the
design matrix, we show that it is possible to define a simple index that
exhibits strong connections with the $D$-optimality.


title: Cassini observations of Saturn's southern polar cusp

abstract:
  The magnetospheric cusps are important sites of the coupling of a
magnetosphere with the solar wind. The combination of both ground- and
space-based observations at Earth have enabled considerable progress to be made
in understanding the terrestrial cusp and its role in the coupling of the
magnetosphere to the solar wind via the polar magnetosphere. Voyager 2 fully
explored Neptune's cusp in 1989 but highly inclined orbits of the Cassini
spacecraft at Saturn present the most recent opportunity to repeatedly studying
the polar magnetosphere of a rapidly rotating planet. In this paper we discuss
observations made by Cassini during two passes through Saturn's southern polar
magnetosphere. Our main findings are that i) Cassini directly encounters the
southern polar cusp with evidence for the entry of magnetosheath plasma into
the cusp via magnetopause reconnection, ii) magnetopause reconnection and entry
of plasma into the cusp can occur over a range of solar wind conditions, and
iii) double cusp morphologies are consistent with the position of the cusp
oscillating in phase with Saturn's global magnetospheric periodicities.


title:
A Proposal for Energy-Efficient Cellular Neural Network based on
  Spintronic Devices

abstract:
  Due to the massive parallel computing capability and outstanding image and
signal processing performance, cellular neural network (CNN) is one promising
type of non-Boolean computing system that can outperform the traditional
digital logic computation and mitigate the physical scaling limit of the
conventional CMOS technology. The CNN was originally implemented by VLSI analog
technologies with operational amplifiers and operational transconductance
amplifiers as neurons and synapses, respectively, which are power and area
consuming. In this paper, we propose a hybrid structure to implement the CNN
with magnetic components and CMOS peripherals with a complete driving and
sensing circuitry. In addition, we propose a digitally programmable magnetic
synapse that can achieve both positive and negative values of the templates.
After rigorous performance analyses and comparisons, optimal energy is achieved
based on various design parameters, including the driving voltage and the CMOS
driving size. At a comparable footprint area and operation speed, a spintronic
CNN is projected to achieve more than one order of magnitude energy reduction
per operation compared to its CMOS counterpart.


title:
Efficient computation of partition of unity interpolants through a
  block-based searching technique

abstract:
  In this paper we propose a new efficient interpolation tool, extremely
suitable for large scattered data sets. The partition of unity method is used
and performed by blending Radial Basis Functions (RBFs) as local approximants
and using locally supported weight functions. In particular we present a new
space-partitioning data structure based on a partition of the underlying
generic domain in blocks. This approach allows us to examine only a reduced
number of blocks in the search process of the nearest neighbour points, leading
to an optimized searching routine. Complexity analysis and numerical
experiments in two- and three-dimensional interpolation support our findings.
Some applications to geometric modelling are also considered. Moreover, the
associated software package written in \textsc{Matlab} is here discussed and
made available to the scientific community.


title:
Robust Reduced-Order Model Stabilization for Partial Differential
  Equations Based on Lyapunov Theory and Extremum Seeking with Application to
  the 3D Boussinesq Equations

abstract:
  We present some results on stabilization for reduced-order models (ROMs) of
partial differential equations. The stabilization is achieved using Lyapunov
theory to design a new closure model that is robust to parametric
uncertainties. The free parameters in the proposed ROM stabilization method are
optimized using a model-free multi-parametric extremum seeking (MES) algorithm.
The 3D Boussinesq equations provide a challenging numerical test-problem that
is used to demonstrate the advantages of the proposed method.


title:
Digital Adaptive Carrier Phase Estimation in Multi-Level Phase Shift
  Keying Coherent Optical Communication Systems

abstract:
  The analysis of adaptive carrier phase estimation is investigated in
long-haul high speed n-level phase shift keying (n-PSK) optical fiber
communication systems based on the one-tap normalized least-mean-square (LMS)
algorithm. The close-form expressions for the estimated carrier phase and the
bit-error-rate floor have been derived in the n-PSK coherent optical
transmission systems. The results show that the one-tap normalized LMS
algorithm performs pretty well in the carrier phase estimation, but will be
less effective with the increment of modulation levels, in the compensation of
both intrinsic laser phase noise and equalization enhanced phase noise.


title:
Mathematical Analysis and Dynamic Active Subspaces for a Long term model
  of HIV

abstract:
  Recently, a long-term model of HIV infection dynamics was developed to
describe the entire time course of the disease. It consists of a large system
of ODEs with many parameters, and is expensive to simulate. In the current
paper, this model is analyzed by determining all infection-free steady states
and studying the local stability properties of the unique biologically-relevant
equilibrium. Active subspace methods are then used to perform a global
sensitivity analysis and study the dependence of an infected individual's
T-cell count on the parameter space. Building on these results, a
global-in-time approximation of the T-cell count is created by constructing
dynamic active subspaces and reduced order models are generated, thereby
allowing for inexpensive computation.


title:
Gamma ray signals of the annihilation of Higgs-portal singlet dark
  matter

abstract:
  This article is an exploration of gamma ray signals of annihilating
Higgs-portal singlet scalar and vector dark matter. Gamma ray signals are
considered in the context of contributions from annihilations of singlets in
the galactic halo to the Isotropic Gamma Ray Background (IGRB), in the context
of the Galactic center excess, and in the context of observations of dwarf
spheroidal galaxies. We find that Higgs-portal singlets of both species with a
mass of $~$65 GeV can explain the Galactic center excess with reasonable
accuracy, but that this mass range is in tension with current direct detection
bounds. We also find that singlets in the mass range of 250-1000 GeV are
consistent with both the Fermi-LAT IGRB observations and direct detection
bounds. Additionally, bounds from gamma ray observations of the dwarf
spheroidal galaxy Segue I are translated into bounds on the Higgs-portal
couplings.


title:
Separated Characteristics and Global Solvability for the one and
  one-half dimensional Vlasov Maxwell System

abstract:
  The motion of a collisionless plasma - a high-temperature, low-density,
ionized gas - is described by the Vlasov-Maxwell (VM) system. These equations
are considered in one space dimension and two momentum dimensions without the
assumption of relativistic velocity corrections. The main results are bounds on
the spatial and velocity supports of the particle distribution function and
uniform estimates on derivatives of this function away from the critical
velocity $| v_1 | = 1$. Additionally, for initial particle distributions that
are even in the second velocity argument $v_2$, the global-in-time existence of
solutions is shown.


title: An Interference-Free Programming Model for Network Objects

abstract:
  Network objects are a simple and natural abstraction for distributed
object-oriented programming. Languages that support network objects, however,
often leave synchronization to the user, along with its associated pitfalls,
such as data races and the possibility of failure. In this paper, we present
D-SCOOP, a distributed programming model that allows for interference-free and
transaction-like reasoning on (potentially multiple) network objects, with
synchronization handled automatically, and network failures managed by a
compensation mechanism. We achieve this by leveraging the runtime semantics of
a multi-threaded object-oriented concurrency model, directly generalizing it
with a message-based protocol for efficiently coordinating remote objects. We
present our pathway to fusing these contrasting but complementary ideas, and
evaluate the performance overhead of the automatic synchronization in D-SCOOP,
finding that it comes close to---or outperforms---explicit locking-based
synchronization in Java RMI.


title:
Advanced Coordinated Beamforming for the Downlink of Future LTE Cellular
  Networks

abstract:
  Modern cellular networks in traditional frequency bands are notoriously
interference-limited especially in urban areas, where base stations are
deployed in close proximity to one another. The latest releases of Long Term
Evolution (LTE) incorporate features for coordinating downlink transmissions as
an efficient means of managing interference. Recent field trial results and
theoretical studies of the performance of joint transmission (JT) coordinated
multi-point (CoMP) schemes revealed, however, that their gains are not as high
as initially expected, despite the large coordination overhead. These schemes
are known to be very sensitive to defects in synchronization or information
exchange between coordinating bases stations as well as uncoordinated
interference. In this article, we review recent advanced coordinated
beamforming (CB) schemes as alternatives, requiring less overhead than JT CoMP
while achieving good performance in realistic conditions. By stipulating that,
in certain LTE scenarios of increasing interest, uncoordinated interference
constitutes a major factor in the performance of CoMP techniques at large, we
hereby assess the resilience of the state-of-the-art CB to uncoordinated
interference. We also describe how these techniques can leverage the latest
specifications of current cellular networks, and how they may perform when we
consider standardized feedback and coordination. This allows us to identify
some key roadblocks and research directions to address as LTE evolves towards
the future of mobile communications.


title: Traffic Modeling and Real-time Control for Metro Lines

abstract:
  We present in this article traffic flow and control models for the train
dynamics in metro lines. The first model, written in the max-plus algebra,
takes into account minimum running, dwell and safety time constraints, without
any control of the train dwell times at platforms, and without consideration of
the passenger travel demand. We show that the dynamics are stable and converge
to stationary regimes with a unique asymptotic average growth rate. Moreover,
the asymptotic average train time-headway, dwell time, as well as close-in
time, are derived analytically, as functions of the number of running trains on
the metro line. We then introduce, in a second model, the effect of the
passenger demand on the train dwell times at platforms. We review that, if this
effect is not well controlled, then the traffic is unstable. Finally, we
propose a traffic control model which deals with this instability, by well
controlling the effect of passenger arrivals on the train dwell times at
platforms. We show that the dynamics are stable and converge to stationary
regimes with a unique asymptotic average growth rate. We then calculate by
numerical simulations the asymptotic average time-headway as a function of the
number of running trains, compare the results with those of the max-plus
algebra model, and derive the effect of the passenger travel demand on the
frequency of the metro line, under the proposed control model.


title:
Electron magnetic resonance in magnetic nanoparticles: dependence on the
  particle size and applicability of the modified giant spin model

abstract:
  Superparamagnetic nanoparticles containing hundreds and thousands of coupled
electron spins are on the boundary between classical and quantum behavior, and
demonstrate features which are typical for paramagnetic spins and absent in
macroscopic ferromagnetic systems. In order to better understand the evolution
of magnetization dynamics from quantum to classical behavior with the increase
in the system size, we study the electron magnetic resonance signal in
suspensions of iron oxide nanoparticles as the function of the particle size.
The experimental data are compared with numerical simulations based on the
giant spin approach.


title:
Active Versus Passive: Receiver Model Transforms for Diffusive Molecular
  Communication

abstract:
  This paper presents an analytical comparison of active and passive receiver
models in diffusive molecular communication. In the active model, molecules are
absorbed when they collide with the receiver surface. In the passive model, the
receiver is a virtual boundary that does not affect molecule behavior. Two
approaches are presented to derive transforms between the receiver signals. As
an example, two models for an unbounded diffusion-only molecular communication
system with a spherical receiver are unified. As time increases in the
three-dimensional system, the transform functions have constant scaling
factors, such that the receiver models are effectively equivalent. Methods are
presented to enable the transformation of stochastic simulations, which are
used to verify the transforms and demonstrate that transforming the simulation
of a passive receiver can be more efficient and more accurate than the direct
simulation of an absorbing receiver.


title: Particle Path Through a Nested Mach-Zehnder Interferometer

abstract:
  Possible paths of a photon passing through a nested Mach-Zehnder
interferometer on its way to a detector are analyzed using the consistent
histories formulation of quantum mechanics, and confirmed using a set of weak
measurements (but not weak values). The results disagree with an analysis by
Vaidman [ Phys.\ Rev.\ A 87 (2013) 052104 ], and agree with a conclusion
reached by Li et al.\ [ Phys.\ Rev.\ A 88 (2013) 046102 ]. However, the
analysis casts serious doubt on the claim of Salih et al.\ (whose authorship
includes Li et al.) [ Phys.\ Rev.\ Lett.\ 110 (2013) 170502 ] to have
constructed a protocol for counterfactual communication: a channel which can
transmit information even though it contains a negligible number of photons.


title: Ultra-relativistic nuclear collisions: where the spectators flow?

abstract:
  In high energy heavy ion collisions, the directed flow of particles is
conventionally measured with respect to that of the projectile spectators,
which is defined as positive $x$ direction. But it is not known if the
spectators deflect in the "outward" direction or "inward" -- toward the center
line of the collision. In this Letter we discuss how the measurements of the
directed flow at mid-rapidity, especially in asymmetric collision such as
Cu+Au, can be used to answer this question. We show that the existing data
strongly favor the case that the spectators, in the ultrarelativistic
collisions, on average deflect outwards.


title: $1$-perfectly orientable $K_4$-minor-free and outerplanar graphs

abstract:
  A graph $G$ is said to be $1$-perfectly orientable if it has an orientation
such that for every vertex $v\in V(G)$, the out-neighborhood of $v$ in $D$ is a
clique in $G$. In $1982$, Skrien posed the problem of characterizing the class
of $1$-perfectly orientable graphs. This graph class forms a common
generalization of the classes of chordal and circular arc graphs; however,
while polynomially recognizable via a reduction to $2$-SAT, no structural
characterization of this intriguing class of graphs is known. Based on a
reduction of the study of $1$-perfectly orientable graphs to the biconnected
case, we characterize, both in terms of forbidden induced minors and in terms
of composition theorems, the classes of $1$-perfectly orientable
$K_4$-minor-free graphs and of $1$-perfectly orientable outerplanar graphs. As
part of our approach, we introduce a class of graphs defined similarly as the
class of $2$-trees and relate the classes of graphs under consideration to two
other graph classes closed under induced minors studied in the literature:
cyclically orientable graphs and graphs of separability at most~$2$.


title: Dark photons in the Dalitz-like decay of a scalar

abstract:
  The couplings of the Standard Model sector to the scale invariant degrees of
freedom can open the possibility to study dark photons (DP). The Dalitz-like
decay of the (Higgs-like) scalar boson into a single photon and DP is studied.
The interaction between DP and quarks is mediated by the derivative of the
scalar field - the dilaton, the virtual (fictitious) state. The mass of the
dilaton does not enter the final solutions. Upper limits are set on the DP
mass, the mixing strength between the standard photon and DP. The model does
allow to estimate the DP mass with the value of 4.5 MeV.


title:
Estimation of low rank density matrices: bounds in Schatten norms and
  other distances

abstract:
  Let ${\mathcal S}_m$ be the set of all $m\times m$ density matrices
(Hermitian positively semi-definite matrices of unit trace). Consider a problem
of estimation of an unknown density matrix $\rho\in {\mathcal S}_m$ based on
outcomes of $n$ measurements of observables $X_1,\dots, X_n\in {\mathbb H}_m$
(${\mathbb H}_m$ being the space of $m\times m$ Hermitian matrices) for a
quantum system identically prepared $n$ times in state $\rho.$ Outcomes
$Y_1,\dots, Y_n$ of such measurements could be described by a trace regression
model in which ${\mathbb E}_{\rho}(Y_j|X_j)={\rm tr}(\rho X_j), j=1,\dots, n.$
The design variables $X_1,\dots, X_n$ are often sampled at random from the
uniform distribution in an orthonormal basis $\{E_1,\dots, E_{m^2}\}$ of
${\mathbb H}_m$ (such as Pauli basis). The goal is to estimate the unknown
density matrix $\rho$ based on the data $(X_1,Y_1), \dots, (X_n,Y_n).$ Let $$
\hat Z:=\frac{m^2}{n}\sum_{j=1}^n Y_j X_j $$ and let $\check \rho$ be the
projection of $\hat Z$ onto the convex set ${\mathcal S}_m$ of density
matrices. It is shown that for estimator $\check \rho$ the minimax lower bounds
in classes of low rank density matrices (established earlier) are attained up
logarithmic factors for all Schatten $p$-norm distances, $p\in [1,\infty]$ and
for Bures version of quantum Hellinger distance. Moreover, for a slightly
modified version of estimator $\check \rho$ the same property holds also for
quantum relative entropy (Kullback-Leibler) distance between density matrices.


title: Radiation hydrodynamical models of the inner rim in protoplanetary disks

abstract:
  Many stars host planets orbiting within a few astronomical units (AU). The
occurrence rate and distributions of masses and orbits vary greatly with the
host stars mass. These close planets origins are a mystery that motivates
investigating protoplanetary disks central regions. A key factor governing the
conditions near the star is the silicate sublimation front, which largely
determines where the starlight is absorbed, and which is often called the inner
rim. We present the first radiation hydrodynamical modeling of the sublimation
front in the disks around the young intermediate-mass stars called Herbig Ae
stars. The models are axisymmetric, and include starlight heating, silicate
grains sublimating and condensing to equilibrium at the local, time-dependent
temperature and density, and accretion stresses parametrizing the results of
MHD magneto-rotational turbulence models. The results compare well with
radiation hydrostatic solutions, and prove to be dynamically stable. Passing
the model disks into Monte Carlo radiative transfer calculations, we show that
the models satisfy observational constraints on the inner rims location. A
small optically-thin halo of hot dust naturally arises between the inner rim
and the star. The inner rim has a substantial radial extent, corresponding to
several disk scale heights. While the fronts overall position varies with the
stellar luminosity, its radial extent depends on the mass accretion rate. A
pressure maximum develops near the location of thermal ionization at
temperatures about 1000 K. The pressure maximum is capable of halting solid
pebbles radial drift and concentrating them in a zone where temperatures are
sufficiently high for annealing to form crystalline silicates.


title: Beam Normal Single Spin Asymmetry Measurements from QWeak

abstract:
  The Q weak experiment has made several interesting beam normal single spin
asymmetry measurements. Preliminary result from a 3.2% measurement of the beam
normal single spin asymmetry in elastic e+p scattering at E = 1.155 GeV and
{\theta} lab = 7.8(deg) is presented. We have also made measurements of this
asymmetry in elastic and inelastic scattering in the Delta resonance region
from Hydrogen, Aluminum and Carbon targets and e+e scattering from Hydrogen
target. Some initial results from these measurements are also presented.