title:
Resource Allocation in Dynamic TDD Heterogeneous Networks under Mixed
  Traffic

abstract:
  Recently, Dynamic Time Division Duplex (TDD) has been proposed to handle the
asymmetry of traffic demand between DownLink (DL) and UpLink (UL) in
Heterogeneous Networks (HetNets). However, for mixed traffic consisting of best
effort traffic and soft Quality of Service (QoS) traffic, the resource
allocation problem has not been adequately studied in Dynamic TDD HetNets. In
this paper, we focus on such problem in a two-tier HetNet with co-channel
deployment of one Macro cell Base Station (MBS) and multiple Small cell Base
Stations (SBSs) in hotspots. Different from existing work, we introduce low
power almost blank subframes to alleviate MBS-to-SBS interference which is
inherent in TDD operation. To tackle the resource allocation problem, we
propose a two-step strategy. First, from the view point of base stations, we
propose a transmission protocol and perform time resource allocation by
formulating and solving a network capacity maximization problem under DL/UL
traffic demands. Second, from the view point of User Equipments (UEs), we
formulate their resource allocation as a Network Utility Maximization (NUM)
problem. An efficient iterative algorithm is proposed to solve the NUM problem.
Simulations show the advantage of the proposed algorithm in terms of network
throughput and UE QoS satisfaction level.


title: Optimal laser pulse energy partitioning for air ionization

abstract:
  We investigate the pulse partitioning of a 6.3 mJ, 450 fs pulse at 1030 nm to
produce plasma channels. At such moderate energies, splitting the energy into
several sub-pulses reduces the ionization efficiency and thus does not extend
the plasma lifetime. We numerically show that when sufficient energy to produce
multifilamentation is available, splitting the pulse temporally in a pulse
train increases the gas temperature compared to a filament bundle of the same
energy. This could improve the mean free path of the free electrons, therefore
enhancing the efficiency of discharge triggering.


title: The intrinsic beauty of polytropic spheres in reduced variables

abstract:
  The concept of reduced variables is revisited with regard to van der Waals'
theory and an application is made to polytropic spheres, where the reduced
radial coordinate is ${\rm red}(r)=r/R=\xi/\Xi$, $R$ radius, and the reduced
density is ${\rm red}(\rho)=\rho/\lambda=\theta^n$, $\lambda$ central density.
Reduced density profiles are plotted for several polytropic indexes within the
range, $0\le n\le5$, disclosing two noticeable features. First, any point of
coordinates, $({\rm red}(r),{\rm red}(\rho))$, $0\le{\rm red}(r)\le1$,
$0\le{\rm red}(\rho)\le1$, belongs to a reduced density profile of the kind
considered. Second, sufficiently steep i.e. large $n$ reduced density profiles
exhibit an oblique inflection point, where the threshold is found to be located
at $n=n_{\rm th}=0.888715$. Reduced pressure profiles, ${\rm
red}(P)=P/\varpi=\theta^{n+1}$, $\varpi$ central pressure, Lane-Emden
fucntions, $\theta=(\rho/\lambda)^{1/n}$, and polytropic curves, ${\rm
red}(P)={\rm red}(P)({\rm red}(\rho))$, are also plotted. The method can be
extended to nonspherical polytropes with regard to a selected direction, ${\rm
red}(r)(\mu)=r(\mu)/R(\mu)=\xi(\mu)/\Xi(\mu)$. The results can be extended to
polytropic spheres made of collisionless particles, for polytropic index within
a more restricted range, $1/2\le n\le5$.


title: Robust Named Entity Recognition in Idiosyncratic Domains

abstract:
  Named entity recognition often fails in idiosyncratic domains. That causes a
problem for depending tasks, such as entity linking and relation extraction. We
propose a generic and robust approach for high-recall named entity recognition.
Our approach is easy to train and offers strong generalization over diverse
domain-specific language, such as news documents (e.g. Reuters) or biomedical
text (e.g. Medline). Our approach is based on deep contextual sequence learning
and utilizes stacked bidirectional LSTM networks. Our model is trained with
only few hundred labeled sentences and does not rely on further external
knowledge. We report from our results F1 scores in the range of 84-94% on
standard datasets.


title:
Non-Gaussian quasi-likelihood estimation of SDE driven by locally stable
  L\'evy process

abstract:
  We address estimation of parametric coefficients of a pure-jump L\'evy driven
univariate stochastic differential equation (SDE) model, which is observed at
high frequency over a fixed time period. It is known from the previous study
Masuda (2013) that adopting the conventional Gaussian quasi-maximum likelihood
estimator then leads to an inconsistent estimator. In this paper, under the
assumption that the driving L\'evy process is locally stable, we extend the
Gaussian framework into a non-Gaussian counterpart, by introducing a novel
quasi-likelihood function formally based on the small-time stable approximation
of the unknown transition density. The resulting estimator turns out to be
asymptotically mixed normally distributed without ergodicity and finite moments
for a wide range of the driving pure-jump L\'evy process, showing much better
theoretical performance compared with the Gaussian quasi-maximum likelihood
estimator. Extensive simulations are carried out to show good estimation
accuracy. The case of large-time asymptotics under ergodicity is briefly
mentioned as well, where we can deduce an analogous asymptotic normality
result.


title:
Systematic Evaluation of Sandboxed Software Deployment for Real-time
  Software on the Example of a Self-Driving Heavy Vehicle

abstract:
  Companies developing and maintaining software-only products like web shops
aim for establishing persistent links to their software running in the field.
Monitoring data from real usage scenarios allows for a number of improvements
in the software life-cycle, such as quick identification and solution of
issues, and elicitation of requirements from previously unexpected usage. While
the processes of continuous integration, continuous deployment, and continuous
experimentation using sandboxing technologies are becoming well established in
said software-only products, adopting similar practices for the automotive
domain is more complex mainly due to real-time and safety constraints. In this
paper, we systematically evaluate sandboxed software deployment in the context
of a self-driving heavy vehicle that participated in the 2016 Grand Cooperative
Driving Challenge (GCDC) in The Netherlands. We measured the system's
scheduling precision after deploying applications in four different execution
environments. Our results indicate that there is no significant difference in
performance and overhead when sandboxed environments are used compared to
natively deployed software. Thus, recent trends in software architecting,
packaging, and maintenance using microservices encapsulated in sandboxes will
help to realize similar software and system engineering for cyber-physical
systems.


title:
Multiplicities of charged kaons from deep-inelastic muon scattering off
  an isoscalar target

abstract:
  Precise measurements of charged-kaon multiplicities in deep inelastic
scattering were performed. The results are presented in three-dimensional bins
of the Bjorken scaling variable x, the relative virtual-photon energy y, and
the fraction z of the virtual-photon energy carried by the produced hadron. The
data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off
an isoscalar 6 LiD target. They cover the kinematic domain 1 (GeV/c)2 < Q2 < 60
(GeV/c)^2 in the photon virtuality, 0.004 < x < 0.4, 0.1 < y < 0.7, 0.20 < z <
0.85, and W > 5 GeV/c^2 in the invariant mass of the hadronic system. The
results from the sum of the z-integrated K+ and K- multiplicities at high x
point to a value of the non-strange quark fragmentation function larger than
obtained by the earlier DSS fit.


title: A Study of Vision based Human Motion Recognition and Analysis

abstract:
  Vision based human motion recognition has fascinated many researchers due to
its critical challenges and a variety of applications. The applications range
from simple gesture recognition to complicated behaviour understanding in
surveillance system. This leads to major development in the techniques related
to human motion representation and recognition. This paper discusses
applications, general framework of human motion recognition, and the details of
each of its components. The paper emphasizes on human motion representation and
the recognition methods along with their advantages and disadvantages. This
study also discusses the selected literature, popular datasets, and concludes
with the challenges in the domain along with a future direction. The human
motion recognition domain has been active for more than two decades, and has
provided a large amount of literature. A bird's eye view for new researchers in
the domain is presented in the paper.


title:
Hamiltonian Magnetohydrodynamics: Lagrangian, Eulerian, and Dynamically
  Accessible Stability -- Examples with Translation Symmetry

abstract:
  Because different constraints are imposed, stability conditions for
dissipationless fluids and magnetofluids may take different forms when derived
within the Lagrangian, Eulerian (energy-Casimir), or dynamical accessible
frameworks. This is in particular the case when flows are present. These
differences are explored explicitly by working out in detail two
magnetohydrodynamic examples: convection against gravity in a stratified fluid
and translationally invariant perturbations of a rotating magnetized plasma
pinch. In this second example we show in explicit form how to perform the
time-dependent relabeling introduced in Andreussi {\it et al.}\ [Phys.\ Plasmas
{\bf20}, 092104 (2013)] that makes it possible to reformulate Eulerian
equilibria with flows as Lagrangian equilibria in the relabeled variables. The
procedures detailed in the present article provide a paradigm that can be
applied to more general plasma configurations and in addition extended to more
general plasma descriptions where dissipation is absent.

categories: physics.plasm-ph math-ph math.MP physics.flu-dyn


title:
Topological Dirac line nodes and superconductivity coexist in SnSe at
  high pressure

abstract:
  Due to fundamental interest and potential applications in quantum
computation, tremendous efforts have been invested to study topological
superconductivity. However, bulk topological superconductivity seems to be
difficult to realize and its mechanism is still elusive. Several possible
routes to induce topological superconductivity have been proposed, including
proximity efforts, doping or pressurizing a topological insulator or semimetal.
Among them, the pressurizing is considered to be a clean way to tune the
electronic structures. Here we report the discovery of a pressure-induced
topological and superconducting phase of SnSe, a material which is highly
focused recently due to its superior thermoelectric properties. In situ
high-pressure electrical transport and synchrotron X-ray diffraction
measurements show that the superconductivity emerges along with the formation
of a CsCl-type structural symmetry of SnSe above around 27 GPa, with a maximum
critical temperature of 3.2 K at 39 GPa. Based on ab initio calculations, this
CsCl-type SnSe is predicted to be a Dirac line nodes (DLN) semimetal in the
absence of spin-orbit coupling, whose DLN states are protected by the
coexistence of time-reversal and inversion symmetries. These results make
CsCl-type SnSe an interesting model platform with simple crystal symmetry to
study the interplay of topological physics and superconductivity.


title: Evolution of spherical overdensities in new agegraphic dark energy model

abstract:
  We study the structure formation by investigating the spherical collapse
model in the context of new agegraphic dark energy model in flat FRW cosmology.
We compute the perturbational quantities $g(a)$, $\delta_{c}(z_{c})$,
$\lambda(z_{c})$, $\xi(z_{c})$, $\Delta_{vir}(z_{c})$, $\log[\nu f(\nu)]$ and
$\log[n(k)]$ for the new agegraphic dark energy model and compare the results
with those of EdS and $\Lambda CDM$ models. We find that there is a dark energy
dominated universe at low redshifts and a matter dominated universe at high
redshifts in agreement with observations. Also, the size of structures, the
overdense spherical region, and the halo size in the new agegraphic dark energy
model are found smaller, denser, and larger than those of EdS and $\Lambda CDM$
models. We compare our results with the results of tachyon scalar field and
holographic dark energy models.


title:
Gauge-Independent Scales Related to the Standard Model Vacuum
  Instability

abstract:
  The measured (central) values of the Higgs and top quark masses indicate that
the Standard Model (SM) effective potential develops an instability at high
field values. The scale of this instability, determined as the Higgs field
value at which the potential drops below the electroweak minimum, is about
$10^{11}$ GeV. However, such a scale is unphysical as it is not gauge-invariant
and suffers from a gauge-fixing uncertainty of up to two orders of magnitude.
Subjecting our system, the SM, to several probes of the instability (adding
higher order operators to the potential; letting the vacuum decay through
critical bubbles; heating up the system to very high temperature; inflating it)
and asking in each case physical questions, we are able to provide several
gauge-invariant scales related with the Higgs potential instability.


title: On quantum statistical mechanics; A study guide

abstract:
  These notes are intended as an introduction to a study of applications of
noncommutative calculus to quantum statistical Physics. Centered on
noncommutative calculus we describe the physical concepts and mathematical
structures appearing in the analysis of large quantum systems, and their
consequences. These include the emergence of algebraic approach and the
necessity of employment of infinite dimensional structures. As an illustration,
a quantization of stochastic processes, new formalism for statistical
mechanics, quantum field theory and quantum correlations are discussed.


title:
On-line Joint Limit Avoidance for Torque Controlled Robots by Joint
  Space Parametrization

abstract:
  This paper proposes control laws ensuring the stabilization of a time-varying
desired joint trajectory, as well as joint limit avoidance, in the case of
fully-actuated manipulators. The key idea is to perform a parametrization of
the feasible joint space in terms of exogenous states. It follows that the
control of these states allows for joint limit avoidance. One of the main
outcomes of this paper is that position terms in control laws are replaced by
parametrized terms, where joint limits must be avoided. Stability and
convergence of time-varying reference trajectories obtained with the proposed
method are demonstrated to be in the sense of Lyapunov. The introduced control
laws are verified by carrying out experiments on two degrees-of-freedom of the
humanoid robot iCub.


title:
On the influence of impact effect modelling for global asteroid impact
  risk distribution

abstract:
  ESA and NASA maintain asteroid hazard lists that contain all known asteroids
with a non zero chance of colliding with the Earth in the future. Some software
tools exist that are, either, capable of calculating the impact points of those
asteroids, or that can estimate the impact effects of a given impact incident.
However, no single tool is available that combines both aspects and enables a
comprehensive risk analysis. The question is, thus, whether tools that can
calculate impact location may be used to obtain a qualitative understanding of
the asteroid impact risk distribution. To answer this question, two impact risk
distributions that control for impact effect modelling were generated and
compared. The Asteroid Risk Mitigation Optimization and Research (ARMOR) tool,
in conjunction with the freely available software OrbFit, was used to project
the impact probabilities of listed asteroids with a minimum diameter of 30 m
onto the surface of the Earth representing a random sample (15% of all objects)
of the hazard list. The resulting 261 impact corridors were visualized on a
global map. Furthermore, the impact corridors were combined with Earth
population data to estimate the simplified risk (without impact effects) and
advanced risk (with impact effects) associated with the direct asteroid impacts
that each nation faces from present to 2100 based on this sample. The
relationship between risk and population size was examined for the 40 most
populous countries and it was apparent that population size is a good proxy for
relative risk. The advanced and simplified risk distributions were compared and
the alteration of the results based on the introduction of physical impact
effects was discussed. Population remained a valid proxy for relative impact
risk, but the inclusion of impact effects resulted in significantly different
risks, especially when considered at the national level.


title:
Direct likelihood-based inference for discretely observed stochastic
  compartmental models of infectious disease

abstract:
  Stochastic compartmental models are important tools for understanding the
course of infectious diseases epidemics in populations and in prospective
evaluation of intervention policies. However, calculating the likelihood for
discretely observed data from even simple models -- such as the ubiquitous
susceptible-infectious-removed (SIR) model -- has been considered
computationally intractable, since its formulation almost a century ago.
Recently researchers have proposed methods to circumvent this limitation
through data augmentation or approximation, but these approaches often suffer
from high computational cost or loss of accuracy. We develop the mathematical
foundation and an efficient algorithm to compute the likelihood for discretely
observed data from a broad class of stochastic compartmental models. We also
give expressions for the derivatives of the transition probabilities using the
same technique, making possible inference via Hamiltonian Monte Carlo (HMC). We
use the 17th century plague in Eyam, a classic example of the SIR model, to
compare our recursion method to sequential Monte Carlo, analyze using HMC, and
assess the model assumptions. We also apply our direct likelihood evaluation to
perform Bayesian inference for the 2014-2015 Ebola outbreak in Guinea. The
results suggest that the epidemic infectious rates have decreased since October
2014 in the Southeast region of Guinea, while rates remain the same in other
regions, facilitating understanding of the outbreak and the effectiveness of
Ebola control interventions.


title: Automatic Synchronization of Multi-User Photo Galleries

abstract:
  In this paper we address the issue of photo galleries synchronization, where
pictures related to the same event are collected by different users. Existing
solutions to address the problem are usually based on unrealistic assumptions,
like time consistency across photo galleries, and often heavily rely on
heuristics, limiting therefore the applicability to real-world scenarios. We
propose a solution that achieves better generalization performance for the
synchronization task compared to the available literature. The method is
characterized by three stages: at first, deep convolutional neural network
features are used to assess the visual similarity among the photos; then, pairs
of similar photos are detected across different galleries and used to construct
a graph; eventually, a probabilistic graphical model is used to estimate the
temporal offset of each pair of galleries, by traversing the minimum spanning
tree extracted from this graph. The experimental evaluation is conducted on
four publicly available datasets covering different types of events,
demonstrating the strength of our proposed method. A thorough discussion of the
obtained results is provided for a critical assessment of the quality in
synchronization.


title:
A priori stopping rule for an iterative Bregman method for optimal
  control problems

abstract:
  In this article we continue our investigation of the iterative regularization
method for optimization problems based on Bregman distances. The optimization
problems are subject to pointwise inequality constraints in $L^2(\Omega)$. We
provide an estimate for the noise error for perturbed data, which can be used
to construct an a priori stopping rule. Furthermore we show how to implement
our method with a semi-smooth Newton method using finite elements and present
numerical results for the stopping rule.


title:
Impacts of stellar evolution and dynamics on the habitable zone: The
  role of rotation and magnetic activity

abstract:
  In this article, we aim to provide the community with the dependence of the
habitable zone upon the stellar mass, metallicity, rotation, and for various
prescriptions of the limits of the habitable zone. We use the STAREVOL code to
study the evolution of the habitable zone and of the continuously habitable
zone limits. Mass and metallicity are the stellar parameters that have the most
dramatic effects on the habitable zone limits. Conversely, for a given stellar
mass and metallicity, stellar rotation has only a marginal effect on these
limits and does not modify the width of the habitable zone. The evolution of
the habitable zone limits is also correlated to the evolution of the stellar
activity (through the Rossby number) that depends on the stellar mass
considered. While the magnetic activity has negligible consequence in the case
of more massive stars, these effects may have a strong impact on the
habitability of a planet around M dwarf stars. Thus, stellar activity cannot be
neglected and may have strong impacts on the development of life during the
early stage of the continuously habitable zone phase of low-mass stars. Using
observed trends of stellar magnetic field strength we also constrain the
planetary magnetic field (at the zero order) required for a sufficient
magnetospheric protection during the whole stellar evolution. We explicit for
the first time the systematic dependence of planet habitability on stellar
parameters along the full evolution of low- and intermediate-mass stars. These
results can be used as physical inputs for a first order estimation of
exoplanetary habitability.


title:
Low-energy relation for the trace of the energy-momentum tensor in QCD
  and the gluon condensate in a magnetic field

abstract:
  A treatment is given of the nonperturbative QCD vacuum in a magnetic field.
The low-energy equation for the trace of the energy-momentum tensor in a
magnetic field is derived. It is shown that the derivatives with respect to a
magnetic field of the quark and gluon contributions to the trace of the
energy-momentum tensor are equal. The dependence of the gluon condensate on the
magnetic field strength is derived both for strong and weak fields.


title: The depth of the maximal subgroups of Ree groups

abstract:
  We determine the combinatorial and the ordinary depth of the maximal
subgroups of the simple Ree groups, $R(q)$.


title:
Periodic solutions with prescribed minimal period of vortex type problem
  in domains

abstract:
  We consider Hamiltonian systems with two degrees of freedom of point vortex
type \[
  \kappa_j \dot{z}_j = J \nabla_{z_j} H_\Omega(z_1,z_2), \quad j=1,2, \] for
$z_1,z_2$ in a domain $\Omega\subset\mathbb{R}^2$. In the classical point
vortex context the Hamiltonian $H_\Omega$ is of the form \[
  H_\Omega(z_1,z_2) = -\frac{\kappa_1 \kappa_2}{\pi} \log |z_1-z_2| - 2\kappa_1
\kappa_2g(z_1,z_2) - \kappa_1^2 h(z_1) - \kappa_2^2 h(z_2), \] where
$g:\Omega\times\Omega\to\mathbb{R}$ is the regular part of a hydrodynamic Green
function in $\Omega$, $h:\Omega\to\mathbb{R}$ is the Robin function:
$h(z)=g(z,z)$, and $\kappa_1$, $\kappa_2$ are the vortex strengths.
  We prove the existence of infinitely many periodic solutions with prescribed
minimal period that are superpositions of a slow motion of the center of
vorticity close to a star-shaped level line of $h$ and of a fast rotation of
the two vortices around their center of vorticity. The proofs are based on a
recent higher dimensional version of the Poincar\'e-Birkhoff theorem due to
Fonda and Ure\~na.


title: GravityCam: Higher Resolution Visible Wide-Field Imaging

abstract:
  The limits to the angular resolution achievable with conventional
ground-based telescopes are unchanged over 70 years. Atmospheric turbulence
limits image quality to typically ~1 arcsec in practice. We have developed a
new concept of ground-based imaging instrument called GravityCam capable of
delivering significantly sharper images from the ground than is normally
possible without adaptive optics. The acquisition of visible images at high
speed without significant noise penalty has been made possible by advances in
optical and near IR imaging technologies. Images are recorded at high speed and
then aligned before combination and can yield a 3-5 fold improvement in image
resolution. Very wide survey fields are possible with widefield telescope
optics. We describe GravityCam and detail its application to accelerate greatly
the rate of detection of Earth size planets by gravitational microlensing.
GravityCam will also improve substantially the quality of weak shear studies of
dark matter distribution in distant clusters of galaxies. The microlensing
survey will also provide a vast dataset for asteroseismology studies. In
addition, GravityCam promises to generate a unique data set that will help us
understand of the population of the Kuiper belt and possibly the Oort cloud.


title: SPIKE a Processing Software dedicated to Fourier Spectroscopies

abstract:
  We present SPIKE (Spectrometry Processing Innovative KErnel), an open-source
Python package dedicated to Fourier spectroscopies. It provides basic
functionalities such as apodisation, a complete set of Fourier transforms,
phasing for NMR), peak-picking, baseline correction and also tools such as
Linear Prediction. Beside its versatility, the most prominent novelty of this
package is to incorporate new tools for Big Data processing. This is
exemplified by its ability to handle the processing and visualization of very
large data-sets, with multiprocessor capabilities and a low memory footprint.
The software contains also all the tools necessary for the specific fast
processing and visualization of 2D-FTICR-MS data-sets.


title:
Prompt gamma ray diagnostics and enhanced hadron-therapy using
  neutron-free nuclear reactions

abstract:
  We propose a series of simulations about the potential use of Boron isotopes
to trigger neutron-free (aneutronic) nuclear reactions in cancer cells through
the interaction with an incoming energetic proton beam, thus resulting in the
emission of characteristic prompt gamma radiation (429 keV, 718 keV and 1435
keV). Furthermore assuming that the Boron isotopes are absorbed in cancer
cells, the three alpha-particles produced in each p-11B aneutronic nuclear
fusion reactions can potentially result in the enhancement of the biological
dose absorbed in the tumor region since these multi-MeV alpha-particles are
stopped inside the single cancer cell, thus allowing to spare the surrounding
tissues. Although a similar approach based on the use of 11B nuclei has been
proposed in [1], our work demonstrate, using Monte Carlo simulations, the
crucial importance of the use of 10B nuclei (in a solution containing also 11B)
for the generation of prompt gamma-rays, which can be applied to medical
imaging. In fact, we demonstrate that the use of 10B nuclei can enhance the
intensity of the 718 keV gamma-ray peak more than 30 times compared to the
solution containing only 11B nuclei. A detailed explanation of the origin of
the different prompt gamma-rays, as well as of their application as real-time
diagnostics during a potential cancer treatment, is here discussed.


title: Characterizations and representations of core and dual core inverses

abstract:
  In this paper, double commutativity and the reverse order law for the core
inverse are considered. Then, new characterizations of the Moore-Penrose
inverse of a regular element are given by one-sided invertibilities in a ring.
Furthermore, the characterizations and representations of the core and dual
core inverses of a regular element are considered.


title:
Central elements in U(gl(n)), shifted symmetric functions and the
  superalgebraic Capelli's method of virtual variables

abstract:
  In this work, we propose a new method for a unified study of some of the main
features of the theory of the center of the enveloping algebra U(gl(n)) and of
the algebra of shifted symmetric polynomials, that allows the whole theory to
be developed, in a transparent and concise way, from the
representation-theoretic point of view, that is entirely in the center of
U(gl(n)). Our methodological innovation is the systematic use of the
superalgebraic method of virtual variables for gl(n), which is, in turn, an
extension of Capelli's method of "variabili ausiliarie".


title:
Fractal approach towards power-law coherency to measure
  cross-correlations between time series

abstract:
  We focus on power-law coherency as an alternative approach towards studying
power-law cross-correlations between simultaneously recorded time series. To be
able to study empirical data, we introduce three estimators of the power-law
coherency parameter $H_{\rho}$ based on popular techniques usually utilized for
studying power-law cross-correlations -- detrended cross-correlation analysis
(DCCA), detrending moving-average cross-correlation analysis (DMCA) and height
cross-correlation analysis (HXA). In the finite sample properties study, we
focus on the bias, variance and mean squared error of the estimators. We find
that the DMCA-based method is the safest choice among the three. The HXA method
is reasonable for long time series with at least $10^4$ observations, which can
be easily attainable in some disciplines but problematic in others. The
DCCA-based method does not provide favorable properties which even deteriorate
with an increasing time series length. The paper opens a new venue towards
studying cross-correlations between time series.


title:
Determination of two unknown thermal coefficients through an inverse
  one-phase fractional Stefan problem

abstract:
  We consider a semi-infinite one-dimensional phase-change material with two
unknown constant thermal coefficients among the latent heat per unit mass, the
specific heat, the mass density and the thermal conductivity. Aiming at the
determination of them, we consider an inverse one-phase Stefan problem with an
over-specified condition at the fixed boundary and a known evolution for the
moving boundary. We assume that the phase-change process presents latent-heat
memory effects by considering a fractional time derivative of order $\alpha$
($0<\alpha<1$) in the Caputo sense and a sharp front model for the interface.
According to the choice of the unknown thermal coefficients, six inverse
fractional Stefan problems arise. For each of them, we determine necessary and
sufficient conditions on data to obtain the existence and uniqueness of a
solution of similarity type. Moreover, we present explicit expressions for the
temperature and the unknown thermal coefficients. Finally, we show that the
results for the classical statement of this problem, associated with
$\alpha=1$, are obtained through the fractional model when $\alpha\to 1^-$.


title: Second-order perturbation theory: the problem of infinite mode coupling

abstract:
  Second-order self-force computations, which will be essential in modeling
extreme-mass-ratio inspirals, involve two major new difficulties that were not
present at first order. One is the problem of large scales, discussed in [Phys.
Rev. D 92, 104047 (2015)]. Here we discuss the second difficulty, which occurs
instead on small scales: if we expand the field equations in spherical
harmonics, then because the first-order field contains a singularity, we
require an arbitrarily large number of first-order modes to accurately compute
even a single second-order mode. This is a generic feature of nonlinear field
equations containing singularities, allowing us to study it in the simple
context of a scalar toy model in flat space. Using that model, we illustrate
the problem and demonstrate a robust strategy for overcoming it.


title: The twisting Sato-Tate group of the curve $y^2 = x^{8} - 14x^4 + 1$

abstract:
  We determine the twisting Sato-Tate group of the genus $3$ hyperelliptic
curve $y^2 = x^{8} - 14x^4 + 1$ and show that all possible subgroups of the
twisting Sato-Tate group arise as the Sato-Tate group of an explicit twist of
$y^2 = x^{8} - 14x^4 + 1$. Furthermore, we prove the generalized Sato-Tate
conjecture for the Jacobians of all $\mathbb Q$-twists of the curve $y^2 =
x^{8} - 14x^4 + 1$.


title:
Ergodicity of scalar stochastic differential equations with H\"older
  continuous coefficients

abstract:
  It is well-known that for a one dimensional stochastic differential equation
driven by Brownian noise, with coefficient functions satisfying the assumptions
of the Yamada-Watanabe theorem \cite{yamada1,yamada2} and the Feller test for
explosions \cite{feller51,feller54}, there exists a unique stationary
distribution with respect to the Markov semigroup of transition probabilities.
We consider systems on a restricted domain $D$ of the phase space $\mathbb{R}$
and study the rate of convergence to the stationary distribution. Using a
geometrical approach that uses the so called {\it free energy function} on the
density function space, we prove that the density functions, which are
solutions of the Fokker-Planck equation, converge to the stationary density
function exponentially under the Kullback-Leibler {divergence}, thus also in
the total variation norm. The results show that there is a relation between the
Bakry-Emery curvature dimension condition and the dissipativity condition of
the transformed system under the Fisher-Lamperti transformation. Several
applications are discussed, including the Cox-Ingersoll-Ross model and the
Ait-Sahalia model in finance and the Wright-Fisher model in population
genetics.


title:
Anisotropic spin fluctuations in Sr$_2$RuO$_4$: role of spin-orbit
  coupling and induced strain

abstract:
  We analyze the spin anisotropy of the magnetic susceptibility of Sr$_2$RuO$4$
in presence of spin-orbit coupling and anisotropic strain using
quasi-two-dimensional tight-binding parametrization fitted to the ARPES
results. Similar to the previous observations we find the in-plane polarization
of the low ${\bf q}$ magnetic fluctuations and the out-of-plane polarization of
the incommensurate magnetic fluctuation at the nesting wave vector ${\bf Q}_1 =
(2/3 \pi ,2/3 \pi)$ but also nearly isotropic fluctuations near ${\bf
Q}_2=(\pi/6,\pi/6)$. Furthermore, one finds that apart from the high-symmetry
direction of the tetragonal Brillouin zone the magnetic anisotropy is maximal,
i.e. $\chi^{xx} \neq \chi^{yy} \neq \chi^{zz}$. This is the consequence of the
orbital anisotropy of the $xz$ and $yz$ orbitals in the momentum space. We also
study how the magnetic anisotropy evolves in the presence of the strain and
find strong Ising-like ferromagnetic fluctuations near the Lifshitz transition
for the $xy$-band.


title: Expressibility of norms in temporal logic

abstract:
  In this short note we address the issue of expressing norms (such as
obligations and prohibitions) in temporal logic. In particular, we address the
argument from [Governatori 2015] that norms cannot be expressed in Linear Time
Temporal Logic (LTL).


title:
Efficient systematic scheme to construct second-principles
  lattice-dynamical models

abstract:
  We start from the polynomic interatomic potentials introduced by Wojde{\l} et
al. [J. Phys. Condens. Matt. 25, 305401(2013)] and take advantage of one of
their key features -- namely, the linear dependence of the energy on the
potential's adjustable parameters -- to devise a scheme for the construction of
first-principles-based ({\em second-principles}) models for large-scale
lattice-dynamical simulations. Our method presents the following convenient
features. The parameters of the model are computed in a very fast and efficient
way, as it is possible to recast the fit to a training set of first-principles
data into a simple matrix diagonalization problem. Our method selects
automatically the interactions that are most relevant to reproduce the
training-set data, by choosing from a pool that includes virtually all possible
coupling terms, and produces a family of models of increasing complexity and
accuracy. We work with practical and convenient cross-validation criteria
linked to the physical properties that will be relevant in future simulations
based on the new model, and which greatly facilitate the task of identifying a
potential that is simultaneously simple (thus computationally light), very
accurate, and predictive. We also discuss practical ways to guarantee that our
energy models are bounded from below, with a minimal impact on their accuracy.
Finally, we demonstrate our scheme with an application to ferroelastic
perovskite SrTiO$_{3}$, which features many non-trivial lattice-dynamical
features (e.g., a phase transition driven by soft phonons, competing structural
instabilities, highly anharmonic dynamics) and provides a very demanding test.


title:
Molecular Dynamics Simulations of Field Emission From a Prolate
  Spheroidal Tip

abstract:
  High resolution molecular dynamics simulations with full Coulomb interactions
of electrons are used to investigate field emission from a prolate spheroidal
tip. The space charge limited current is several times lower than the current
calculated with the Fowler-Nordheim formula. The image-charge is taken into
account with a spherical approximation, which is good around the top of the
tip, i.e. region where the current is generated.


title: Segal-Bargmann-Fock modules of monogenic functions

abstract:
  In this paper we introduce the classical Segal-Bargmann transform starting
from the basis of Hermite polynomials and extend it to Clifford algebra-valued
functions. Then we apply the results to monogenic functions and prove that the
Segal-Bargmann kernel corresponds to the kernel of the Fourier-Borel transform
for monogenic functionals. This kernel is also the reproducing kernel for the
monogenic Bargmann module.


title:
Exact prior-free probabilistic inference in a class of non-regular
  models

abstract:
  The use of standard statistical methods, such as maximum likelihood, is often
justified based on their asymptotic properties. For suitably regular models,
this theory is standard but, when the model is non-regular, e.g., the support
depends on the parameter, these asymptotic properties may be difficult to
assess. Recently, an inferential model (IM) framework has been developed that
provides valid prior-free probabilistic inference without the need for
asymptotic justification. In this paper, we construct an IM for a class of
highly non-regular models with parameter-dependent support. This construction
requires conditioning, which is facilitated through the solution of a
particular differential equation. We prove that the plausibility intervals
derived from this IM are exact confidence intervals, and we demonstrate their
efficiency in a simulation study.


title:
Quantifying the Survival Uncertainty of Wolbachia-infected Mosquitoes in
  a Spatial Model *

abstract:
  Artificial releases of Wolbachia-infected Aedes mosquitoes have been under
study in the past years for fighting vector-borne diseases such as dengue,
chikungunya and zika. Several strains of this bacterium cause cytoplasmic
incompatibility (CI) and can also affect their host's fecundity or lifespan,
while highly reducing vector competence for the main arboviruses .We consider
and answer the following questions: 1) what should be the initial condition
(i.e. size of the initial mosquito population) to have invasion with one
mosquito release source? We note that it is hard to have an invasion in such
case. 2) How many release points does one need to have sufficiently high
probability of invasion? 3) What happens if one accounts for uncertainty in the
release protocol (e.g. unequal spacing among release points)? We build a
framework based on existing reaction-diffusion models for the uncertainty
quantification in this context, obtain both theoretical and numerical lower
bounds for the probability of release success and give new quantitative results
on the one dimensional case.


title:
Lie algebras with nilpotent length greater than that of each of their
  subalgebras

abstract:
  The main purpose of this paper is to study the finite-dimensional solvable
Lie algebras described in its title, which we call {\em minimal non-${\mathcal
N}$}. To facilitate this we investigate solvable Lie algebras of nilpotent
length $k$, and of nilpotent length $\leq k$, and {\em extreme} Lie algebras,
which have the property that their nilpotent length is equal to the number of
conjugacy classes of maximal subalgebras. We characterise the minimal
non-${\mathcal N}$ Lie algebras in which every nilpotent subalgebra is abelian,
and those of solvability index $\leq 3$.


title:
Improving Sparse Word Representations with Distributional Inference for
  Semantic Composition

abstract:
  Distributional models are derived from co-occurrences in a corpus, where only
a small proportion of all possible plausible co-occurrences will be observed.
This results in a very sparse vector space, requiring a mechanism for inferring
missing knowledge. Most methods face this challenge in ways that render the
resulting word representations uninterpretable, with the consequence that
semantic composition becomes hard to model. In this paper we explore an
alternative which involves explicitly inferring unobserved co-occurrences using
the distributional neighbourhood. We show that distributional inference
improves sparse word representations on several word similarity benchmarks and
demonstrate that our model is competitive with the state-of-the-art for
adjective-noun, noun-noun and verb-object compositions while being fully
interpretable.


title:
Electromagnetic 3D subsurface imaging with source sparsity for a
  synthetic object

abstract:
  This paper concerns electromagnetic 3D subsurface imaging in connection with
sparsity of signal sources. We explored an imaging approach that can be
implemented in situations that allow obtaining a large amount of data over a
surface or a set of orbits but at the same time require sparsity of the signal
sources. Characteristic to such a tomography scenario is that it necessitates
the inversion technique to be genuinely three-dimensional: For example, slicing
is not possible due to the low number of sources. Here, we primarily focused on
astrophysical subsurface exploration purposes. As an example target of our
numerical experiments we used a synthetic small planetary object containing
three inclusions, e.g. voids, of the size of the wavelength. A tetrahedral
arrangement of source positions was used, it being the simplest symmetric point
configuration in 3D. Our results suggest that somewhat reliable inversion
results can be produced within the present a priori assumptions, if the data
can be recorded at a specific resolution. This is valuable early-stage
knowledge especially for design of future planetary missions in which the
payload needs to be minimized, and potentially also for the development of
other lightweight subsurface inspection systems.

categories: astro-ph.IM math-ph math.MP physics.med-ph


title: Velocity segregation effects in galaxy clusters at 0.4<~z<~1.5

abstract:
  Our study is meant to extend our knowledge of the galaxy color and luminosity
segregation in velocity space (VCS and VLS, resp.), to clusters at intermediate
and high redshift. Our sample is a collection of 41 clusters in the 0.4<~z<~1.5
redshift range, for a total of 4172 galaxies, 1674 member galaxies within 2R200
with photometric or spectroscopic information, as taken from the literature. We
pay attention to perform homogeneous procedures to select cluster members,
compute global cluster properties, in particular the LOS velocity dispersion
sigmaV, and separate blue from red galaxies. We find evidence of VCS in
clusters out to z~0.8 (at the 97%-99.99% c.l., depending on the test), in the
sense that the blue galaxy population has a 10-20% larger sigmaV than the red
galaxy population. Poor or no VCS is found in the High-z sample at z>=0.8. For
the first time, we detect VLS in non-local clusters and confirm that VLS only
affects the very luminous galaxies, with brighter galaxies having lower
velocities. The threshold magnitude of VLS is ~m3+0.5, where m3 is the
magnitude of the third brightest cluster galaxy, and current data suggest that
the threshold value moves to fainter magnitudes at higher redshift. We also
detect (marginal) evidence of VLS for blue galaxies. We conclude that the
segregation effects, when their study is extended to distant clusters, can be
important tracers of the galaxy evolution and cluster assembly and discuss the
poor/no evidence of VCS at high redshift.


title: Additive Stabilizers for Unstable Graphs

abstract:
  Stabilization of graphs has received substantial attention in recent years
due to its connection to game theory. Stable graphs are exactly the graphs
inducing a matching game with non-empty core. They are also the graphs that
induce a network bargaining game with a balanced solution. A graph with
weighted edges is called stable if the maximum weight of an integral matching
equals the cost of a minimum fractional weighted vertex cover. If a graph is
not stable, it can be stabilized in different ways. Recent papers have
considered the deletion or addition of edges and vertices in order to stabilize
a graph. In this work, we focus on a fine-grained stabilization strategy,
namely stabilization of graphs by fractionally increasing edge weights. We show
the following results for stabilization by minimum weight increase in edge
weights (min additive stabilizer): (i) Any approximation algorithm for min
additive stabilizer that achieves a factor of $O(|V|^{1/24-\epsilon})$ for
$\epsilon>0$ would lead to improvements in the approximability of
densest-$k$-subgraph. (ii) Min additive stabilizer has no $o(\log{|V|})$
approximation unless NP=P. Results (i) and (ii) together provide the first
super-constant hardness results for any graph stabilization problem. On the
algorithmic side, we present (iii) an algorithm to solve min additive
stabilizer in factor-critical graphs exactly in poly-time, (iv) an algorithm to
solve min additive stabilizer in arbitrary-graphs exactly in time exponential
in the size of the Tutte set, and (v) a poly-time algorithm with approximation
factor at most $\sqrt{|V|}$ for a super-class of the instances generated in our
hardness proofs.


title: Uniqueness of form extensions and domination of semigroups

abstract:
  In this article, we present a new method to study uniqueness of form
extensions in a rather general setting. The method is based on the theory of
ordered Hilbert spaces and the concept of domination of semigroups. Our main
abstract result transfers uniqueness of form extension of a dominating form to
that of a dominated form. This result can be applied to a multitude of examples
including various magnetic Schr\"odinger forms on graphs and on manifolds.


title:
Topological Entropy and bulging deformation of real projective
  structures on surface

abstract:
  In this paper we study the deformation of strictly convex real projective
structures on a closed surface. Specially we study the deformation in terms of
the entropy on bulging deformations. As a byproduct we construct a sequence of
divergent structures whose topological entropy converges to a designated number
between 0 and 1.


title: In the Saddle: Chasing Fast and Repeatable Features

abstract:
  A novel similarity-covariant feature detector that extracts points whose
neighbourhoods, when treated as a 3D intensity surface, have a saddle-like
intensity profile. The saddle condition is verified efficiently by intensity
comparisons on two concentric rings that must have exactly two dark-to-bright
and two bright-to-dark transitions satisfying certain geometric constraints.
Experiments show that the Saddle features are general, evenly spread and
appearing in high density in a range of images. The Saddle detector is among
the fastest proposed. In comparison with detector with similar speed, the
Saddle features show superior matching performance on number of challenging
datasets.


title: Detection of burning ashes from thermonuclear X-ray bursts

abstract:
  When neutron stars (NS) accrete gas from low-mass binary companions,
explosive nuclear burning reactions in the NS envelope fuse hydrogen and helium
into heavier elements. The resulting thermonuclear (type-I) X-ray bursts
produce energy spectra that are fit well with black bodies, but a significant
number of burst observations show deviations from Planck spectra. Here we
present our analysis of RXTE/PCA observations of X-ray bursts from the NS
low-mass X-ray binary HETE J1900.1-2455. We have discovered that the
non-Planckian spectra are caused by photo-ionization edges. The
anti-correlation between the strength of the edges and the colour temperature
suggests that the edges are produced by the nuclear burning ashes that have
been transported upwards by convection and become exposed at the photosphere.
The atmosphere model fits show that occasionally the photosphere can consist
entirely of metals, and that the peculiar changes in black body temperature and
radius can be attributed to the emergence and disappearance of metals in the
photosphere. As the metals are detected already in the Eddington-limited phase,
it is possible that a radiatively driven wind ejects some of the burning ashes
into the interstellar space.


title: Predictive Inference Based on Markov Chain Monte Carlo Output

abstract:
  In Bayesian inference, predictive distributions are typically in the form of
samples generated via Markov chain Monte Carlo (MCMC) or related algorithms. In
this paper, we conduct a systematic analysis of how to make and evaluate
probabilistic forecasts from such simulation output. Based on proper scoring
rules, we develop a notion of consistency that allows to assess the adequacy of
methods for estimating the stationary distribution underlying the simulation
output. We then provide asymptotic results that account for the salient
features of Bayesian posterior simulators, and derive conditions under which
choices from the literature satisfy our notion of consistency. Importantly,
these conditions depend on the scoring rule being used, such that the choices
of approximation method and scoring rule are intertwined. While the logarithmic
rule requires fairly stringent conditions, the continuous ranked probability
score (CRPS) yields consistent approximations under minimal assumptions. These
results are illustrated in a simulation study and an economic data example.
Overall, mixture-of-parameters approximations which exploit the parametric
structure of Bayesian models perform particularly well. Under the CRPS, the
empirical distribution function is a simple and appealing alternative option.


title: Magnetic Phases in Periodically Rippled Graphene

abstract:
  We study the effects that ripples induce on the electrical and magnetic
properties of graphene. The variation of the interatomic distance created by
the ripples translates in a modulation of the hopping parameter between carbon
atoms. A tight binding Hamiltonian including a Hubbard interaction term is
solved self consistently for ripples with different amplitudes and periods. We
find that, for values of the Hubbard interaction $U$ above a critical value
$U_C$, the system displays a superposition of local ferromagnetic and
antiferromagnetic ordered states. Nonetheless the global ferromagnetic order
parameter is zero. The $U_C$ depends only on the product of the period and
hopping amplitude modulation. When the Hubbard interaction is close to the
critical value of the antiferromagnetic transition in pristine graphene, the
antiferromagnetic order parameter becomes much larger than the ferromagnetic
one, being the ground state similar to that of flat graphene.


title:
Total dominating sequences in trees, split graphs, and under modular
  decomposition

abstract:
  A sequence of vertices in a graph $G$ with no isolated vertices is called a
total dominating sequence if every vertex in the sequence totally dominates at
least one vertex that was not totally dominated by preceding vertices in the
sequence, and, at the end all vertices of $G$ are totally dominated (by
definition a vertex totally dominates its neighbors). The maximum length of a
total dominating sequence is called the Grundy total domination number,
$\gamma_{\rm gr}^t(G)$, of $G$, as introduced in [B. Bre\v{s}ar, M.A. Henning,
and D. F. Rall, Total dominating sequences in graphs, Discrete Math. 339
(2016), 1165--1676]. In this paper we continue the investigation of this
concept, mainly from the algorithmic point of view. While it was known that the
decision version of the problem is NP-complete in bipartite graphs, we show
that this is also true if we restrict to split graphs. A linear time algorithm
for determining the Grundy total domination number of an arbitrary tree $T$ is
presented, based on the formula $\gamma_{\rm gr}^t(T)=2\tau(T)$, where
$\tau(T)$ is the vertex cover number of $T$. A similar efficient algorithm is
presented for bipartite distance-hereditary graphs. Using the modular
decomposition of a graph, we present a frame for obtaining polynomial
algorithms for this problem in classes of graphs having relatively simple
modular subgraphs. In particular, a linear algorithm for determining the Grundy
total domination number of $P_4$-tidy graphs is presented. In addition, we
prove a realization result by exhibiting a family of graphs $G_k$ such that
$\gamma_{\rm gr}^t(G_k)=k$, for any $k\in{\mathbb{Z}^+}\setminus\{1,3\}$, and
showing that there are no graphs $G$ with $\gamma_{\rm gr}^t(G)\in \{1,3\}$. We
also present such a family, which has minimum possible order and size among all
graphs with Grundy total domination number equal to $k$.


title: Analyzing two-stage experiments in the presence of interference

abstract:
  Two-stage randomization is a powerful design for estimating treatment effects
in the presence of interference; that is, when one individual's treatment
assignment affects another individual's outcomes. Our motivating example is a
two-stage randomized trial evaluating an intervention to reduce student
absenteeism in the School District of Philadelphia. In that experiment,
households with multiple students were first assigned to treatment or control;
then, in treated households, one student was randomly assigned to treatment.
Using this example, we highlight key considerations for analyzing two-stage
experiments in practice. Our first contribution is to address additional
complexities that arise when household sizes vary; in this case, researchers
must decide between assigning equal weight to households or equal weight to
individuals. We propose unbiased estimators for a broad class of individual-
and household-weighted estimands, with corresponding theoretical and estimated
variances. Our second contribution is to connect two common approaches for
analyzing two-stage designs: linear regression and randomization inference. We
show that, with suitably chosen standard errors, these two approaches yield
identical point and variance estimates, which is somewhat surprising given the
complex randomization scheme. Finally, we explore options for incorporating
covariates to improve precision. We confirm our analytic results via simulation
studies and apply these methods to the attendance study, finding substantively
meaningful spillover effects.


title: Hadron Diffraction: Results and Problems

abstract:
  This is a cursory review of diffractive studies ( mostly elastic
scattering)at the LHC with physical interpretation of the experimental data and
comments to related problems of theory.


title: Efficient Training for Positive Unlabeled Learning

abstract:
  Positive unlabeled (PU) learning is useful in various practical situations,
where there is a need to learn a classifier for a class of interest from an
unlabeled data set, which may contain anomalies as well as samples from unknown
classes. The learning task can be formulated as an optimization problem under
the framework of statistical learning theory. Recent studies have theoretically
analyzed its properties and generalization performance, nevertheless, little
effort has been made to consider the problem of scalability, especially when
large sets of unlabeled data are available. In this work we propose a novel
scalable PU learning algorithm that is theoretically proven to provide the
optimal solution, while showing superior computational and memory performance.
Experimental evaluation confirms the theoretical evidence and shows that the
proposed method can be successfully applied to a large variety of real-world
problems involving PU learning.


title: A Newton conditional gradient method for constrained nonlinear systems

abstract:
  In this paper, we consider the problem of solving a constrained system of
nonlinear equations. We propose an algorithm based on a combination of the
Newton and conditional gradient methods, and establish its local convergence
analysis. Our analysis is set up by using a majorant condition technique,
allowing us to prove in a unified way convergence results for two large
families of nonlinear functions. The first one includes functions whose
derivative satisfies a Holder-like condition, and the second one consists of a
substantial subclass of analytic functions. Numerical experiments illustrating
the applicability of the proposed method are presented, and comparisons with
some other methods are discussed.


title:
A rotational traveling wave based levitation device - Modeling, design,
  and control

abstract:
  Described is a device acting on an acoustically levitated object by
manipulating the pressure and flow of a thin layer of air such that its
rotation can be precisely controlled without mechanical contact. Virtual work
analysis assists in simplifying the multi-actuator control problem into a
problem governed by a controllable parameter. Actuation is done with a
vibrating ring capable of producing ultrasonic standing and traveling waves,
creating the acoustic excitation that affects the pressure in a thin,
intermediate layer of gas. A distinctive vibration pattern is required to
generate the temporal and spatial pressure field of the squeezed air layer that
gives rise to both acoustic levitation force and rotational torque. Described
are the physical and design development stages leading to an optimized
structure, all followed by verifying and dynamics-calibration experiments.
Moreover, by precisely controlling the ratio of standing and traveling waves in
a closed-loop, one can affect the shear forces applied by the squeezed air
layer, thus creating a non-contacting manipulation mechanism. An over-actuated
set-up is converted via an algebraic transformation, into a simplified single
control-parameter problem. The transformation ties the standing waves ratio,
and hence the rotational torque, to the amplitudes and phases of the actuators.
This arrangement leads to an effective closed loop methodology that was
implemented experimentally showing good performance and exhibiting rapid
angular positioning.


title: Short addition sequences for theta functions

abstract:
  The main step in numerical evaluation of classical Sl2 (Z) modular forms and
elliptic functions is to compute the sum of the first N nonzero terms in the
sparse q-series belonging to the Dedekind eta function or the Jacobi theta
constants. We construct short addition sequences to perform this task using N +
o(N) multiplications. Our constructions rely on the representability of
specific quadratic progressions of integers as sums of smaller numbers of the
same kind. For example, we show that every generalised pentagonal number c 5
can be written as c = 2a + b where a, b are smaller generalised pentagonal
numbers. We also give a baby-step giant-step algorithm that uses O(N/ log r N)
multiplications for any r > 0, beating the lower bound of N multiplications
required when computing the terms explicitly. These results lead to speed-ups
in practice.


title: Toric P-Difference Varieties

abstract:
  In this paper, we introduce the concept of P-difference varieties and study
the properties of toric P-difference varieties. Toric P-difference varieties
are analogues of toric varieties in difference algebra geometry. The category
of affine toric P-difference varieties with toric morphisms is shown to be
antiequivalent to the category of affine P[x]-semimodules with P[x]-semimodule
morphisms. Moreover, there is a one-to-one correspondence between the
irreducible invariant P-difference subvarieties of an affine toric P-difference
variety and the faces of the corresponding affine P[x]-semimodule. We also
define abstract toric P-difference varieties associated with fans by gluing
affine toric P-difference varieties. The irreducible invariant P-difference
subvarieties-faces correspondence is generalized to abstract toric P-difference
varieties. By virtue of this correspondence, a divisor theory for abstract
toric P-difference varieties is developed.


title:
High resolution VLBI polarisation imaging of AGN with the Maximum
  Entropy Method

abstract:
  Radio polarisation images of the jets of Active Galactic Nuclei (AGN) can
provide a deep insight into the launching and collimation mechanisms of
relativistic jets. However, even at VLBI scales, resolution is often a limiting
factor in the conclusions that can be drawn from observations. The Maximum
Entropy Method (MEM) is a deconvolution algorithm that can outperform the more
common CLEAN algorithm in many cases, particularly when investigating
structures present on scales comparable to or smaller than the nominal beam
size with "super-resolution". A new implementation of the MEM suitable for
single- or multiple-wavelength VLBI polarisation observations has been
developed and is described here. Monte Carlo simulations comparing the
performances of CLEAN and MEM at reconstructing the properties of model images
are presented; these demonstrate the enhanced reliability of MEM over CLEAN
when images of the fractional polarisation and polarisation angle are
constructed using convolving beams that are appreciably smaller than the full
CLEAN beam. The results of using this new MEM software to image VLBA
observations of the AGN 0716+714 at six different wavelengths are presented,
and compared to corresponding maps obtained with CLEAN. MEM and CLEAN maps of
Stokes $I$, the polarised flux, the fractional polarisation and the
polarisation angle are compared for convolving beams ranging from the full
CLEAN beam down to a beam one-third of this size. MEM's ability to provide more
trustworthy polarisation imaging than a standard CLEAN-based deconvolution when
convolving beams appreciably smaller than the full CLEAN beam are used is
discussed.


title:
The habitability of Proxima Centauri b. I. Irradiation, rotation and
  volatile inventory from formation to the present

abstract:
  Proxima b is a planet with a minimum mass of 1.3 MEarth orbiting within the
habitable zone (HZ) of Proxima Centauri, a very low-mass, active star and the
Sun's closest neighbor. Here we investigate a number of factors related to the
potential habitability of Proxima b and its ability to maintain liquid water on
its surface. We set the stage by estimating the current high-energy irradiance
of the planet and show that the planet currently receives 30 times more EUV
radiation than Earth and 250 times more X-rays. We compute the time evolution
of the star's spectrum, which is essential for modeling the flux received over
Proxima b's lifetime. We also show that Proxima b's obliquity is likely null
and its spin is either synchronous or in a 3:2 spin-orbit resonance, depending
on the planet's eccentricity and level of triaxiality. Next we consider the
evolution of Proxima b's water inventory. We use our spectral energy
distribution to compute the hydrogen loss from the planet with an improved
energy-limited escape formalism. Despite the high level of stellar activity we
find that Proxima b is likely to have lost less than an Earth ocean's worth of
hydrogen before it reached the HZ 100-200 Myr after its formation. The largest
uncertainty in our work is the initial water budget, which is not constrained
by planet formation models. We conclude that Proxima b is a viable candidate
habitable planet.


title: Sub-atom shot noise Faraday imaging of ultracold atom clouds

abstract:
  We demonstrate that a dispersive imaging technique based on the Faraday
effect can measure the atom number in a large, ultracold atom cloud with a
precision below the atom shot noise level. The minimally destructive character
of the technique allows us to take multiple images of the same cloud, which
enables sub-atom shot noise measurement precision of the atom number and allows
for an in situ determination of the measurement precision. We have developed a
noise model that quantitatively describes the noise contributions due to photon
shot noise in the detected light and the noise associated with single atom
loss. This model contains no free parameters and is calculated through an
analysis of the fluctuations in the acquired images. For clouds containing $N
\sim 5 \times 10^6$ atoms, we achieve a precision more than a factor of two
below the atom shot noise level.


title:
Depolarization of high-energy neutral particles in crystals and the
  possibility to measure anomalous magnetic moments of short-lived hyperons

abstract:
  The degree of depolarization of neutral particles in crystals can reach tens
of percents over the crystal length of several centimeters, which can be the
basis for possible experimental application of the depolarization effect for
measuring anomalous magnetic moments of short-lived neutral hyperons.


title:
Hidden Structures of Information Transport Underlying Spiral Wave
  Dynamics

abstract:
  A spiral wave is a macroscopic dynamic of excitable media that plays an
important role in several distinct systems, including the Belousov-Zhabotinsky
reaction, seizures in the brain, and lethal arrhythmia in the heart. Because
spiral wave dynamics can exhibit a wide spectrum of behaviors, its precise
quantification can be challenging. Here we present a hybrid geometric and
information-theoretic approach to quantifying spiral wave dynamics. We
demonstrate the effectiveness of our approach by applying it to numerical
simulations of a two-dimensional excitable medium with different numbers and
spatial patterns of spiral waves. We show that, by defining information flow
over the excitable medium, hidden coherent structures emerge that effectively
quantify the information transport underlying spiral wave dynamics. Most
importantly, we find that some coherent structures become more clearly defined
over a longer observation period. These findings validate our approach to
quantitatively characterize spiral wave dynamics by focusing on information
transport. Our approach is computationally efficient and is applicable to many
excitable media of interest in distinct physical, chemical and biological
systems. Our approach could ultimately contribute to an improved therapy of
clinical conditions such as seizures and cardiac arrhythmia by identifying
potential targets of interventional therapies.


title:
Effects of $\rho$-meson width on pion distributions in heavy-ion
  collisions

abstract:
  The influence of the finite width of $\rho$ meson on the pion momentum
distribution is studied quantitatively in the framework of the S-matrix
approach combined with a blast-wave model to describe particle emissions from
an expanding fireball. We find that the proper treatment of resonances which
accounts for their production dynamics encoded in data for partial wave
scattering amplitudes can substantially modify spectra of daughter particles
originating in their two body decays. In particular, it results in an
enhancement of the low-$p_T$ pions from the decays of $\rho$ mesons which
improves the quantitative description of the pion spectra in heavy ion
collisions obtained by the ALICE collaboration at the LHC energy.


title: Doubled strings, negative strings and null waves

abstract:
  We revisit the fundamental string (F1) solution in the doubled formalism. We
show that the wave-like solution of double field theory (DFT) corresponding to
the F1/pp-wave duality pair is more properly a solution of the DFT action
coupled to a doubled sigma model action. The doubled string configuration which
sources the pp-wave can be thought of as static gauge with the string oriented
in a dual direction. We also discuss the DFT solution corresponding to a
vibrating string, carrying both winding and momentum. We further show that the
solution dual to the F1 in both time and space can be viewed as a "negative
string" solution. Negative branes are closely connected to certain exotic
string theories which involve unusual signatures for both spacetime and brane
worldvolumes. In order to better understand this from the doubled point of
view, we construct a variant of DFT suitable for describing theories in which
the fundamental string has a Euclidean worldsheet, for which T-dualities appear
to change the spacetime signature.


title:
Pricing and Optimization in Shared Vehicle Systems: An Approximation
  Framework

abstract:
  Optimizing shared vehicle systems (bike/scooter/car/ride-sharing) is more
challenging compared to traditional resource allocation settings due to the
presence of \emph{complex network externalities} -- changes in the
demand/supply at any location affect future supply throughout the system within
short timescales. These externalities are well captured by steady-state
Markovian models, which are therefore widely used to analyze such systems.
However, using such models to design pricing and other control policies is
computationally difficult since the resulting optimization problems are
high-dimensional and non-convex.
  To this end, we develop a \emph{rigorous approximation framework} for shared
vehicle systems, providing a unified approach for a wide range of controls
(pricing, matching, rebalancing), objective functions (throughput, revenue,
welfare), and system constraints (travel-times, welfare benchmarks,
posted-price constraints). Our approach is based on the analysis of natural
convex relaxations, and obtains as special cases existing approximate-optimal
policies for limited settings, asymptotic-optimality results, and heuristic
policies. The resulting guarantees are non-asymptotic and parametric, and
provide operational insights into the design of real-world systems. In
particular, for any shared vehicle system with $n$ stations and $m$ vehicles,
our framework obtains an approximation ratio of $1+(n-1)/m$, which is
particularly meaningful when $m/n$, the average number of vehicles per station,
is large, as is often the case in practice.


title: Revised variational approach to QCD in Coulomb gauge

abstract:
  The variational approach to QCD in Coulomb gauge is revisited. By assuming
the non-Abelian Coulomb potential to be given by the sum of its infrared and
ultraviolet parts, i.e.~by a linearly rising potential and an ordinary Coulomb
potential, and by using a Slater determinant ansatz for the quark wave
functional, which contains the coupling of the quarks and the gluons with two
different Dirac structures, we obtain variational equations for the kernels of
the fermionic vacuum wave functional, which are free of ultraviolet
divergences. Thereby, a Gaussian type wave functional is assumed for the
gluonic part of the vacuum. By using the results of the pure Yang--Mills sector
for the gluon propagator as input, we solve the equations for the fermionic
kernels numerically and calculate the quark condensate and the effective quark
mass in leading order. Assuming a value of $\sigma_{\mathrm{C}} = 2.5 \sigma$
for the Coulomb string tension (where $\sigma$ is the usual Wilsonian string
tension) the phenomenological value of the quark condensate $\langle \bar{\psi}
\psi \rangle \simeq (-235 \, \mathrm{MeV})^3$ is reproduced with a value of $g
\simeq 2.1$ for the strong coupling constant of the quark-gluon vertex.


title: Electronic structure of (Ga,Mn)As revisited

abstract:
  The detailed nature of electronic states mediating ferromagnetic coupling in
dilute magnetic semiconductors, specifically (Ga,Mn)As, has been an issue of
long debate. Two confronting models have been discussed emphasizing host band
vs. impurity band carriers. Using angle resolved photoemission we are for the
first time able to identify a highly dispersive Mn-induced energy band in
(Ga,Mn)As. Our results show that the electronic structure of the (Ga,Mn)As
system is significantly modified from that of GaAs throughout the valence band.
Close to the Fermi energy, the presence of Mn induces a strong mixing of the
bulk bands of GaAs, which results in the appearance of a highly dispersive band
in the gap region of GaAs. For Mn concentrations above 1% the band reaches the
Fermi level, and can thus host the delocalized holes needed for ferromagnetic
coupling. Overall, our data provide a firm evidence of delocalized carriers
belonging to the modified host valence band.


title: Creation of single-photon entangled states around rotating black holes

abstract:
  Recently, numerical simulations showed that X-ray photons emitted by
accretion disks acquire rotation of polarization angle and orbital angular
momentum due to strong gravitational field in the vicinity of the rotating
black holes. Based on these two degrees of freedom we construct a bipartite
two-level quantum system of the accretion disk's photons. To characterize the
quantum states of this composite system we consider linear entropy for the
reduced density matrix of polarization with the intention to exploit its direct
relation with the photons degree of polarization. Accordingly, the minimum
degree of polarization of X-ray radiation located in the transition region of
the accretion disk indicates a high value of the linear entropy for the photons
emitted on this region, inferring a high degree of entanglement in the
composite system. We emphasize that for an extreme rotating black hole in the
thermal state, the photons with energies at the thermal peak are maximally
entangled in polarization and orbital angular momentum, leading to the creation
of all four Bell states. Detection and measurement of quantum information
encoded in photons emitted in the accretion disk around rotating black holes
may be performed by actual quantum information technology.


title:
Isogeometric implementation of high order microplane model for the
  simulation of high order elasticity, softening, and localization

abstract:
  In this paper, a recently developed Higher Order Microplane (HOM) model for
softening and localization, is implemented within a isogeometric finite element
framework. The HOM model was derived directly from a three dimensional discrete
particle model and it was shown to be associated with a high order continuum
characterized by independent rotation and displacement fields. Furthermore, the
HOM model possesses two characteristic lengths: the first associated with the
spacing of flaws in the material internal structure and related to the gradient
character of the continuum; and the second associated with the size of these
flaws and related to the micro-polar character of the continuum. The
displacement-based finite element implementation of this type of continua
requires $C^1$ continuity both within the elements and at the element
boundaries. This motivated the implementation of the concept of isogeometric
analysis which ensures a higher degree of smoothness and continuity. NURBS
based isogeometric elements were implemented in a 3D setting, with both
displacement and rotational degrees of freedom at each control point. The
performed numerical analyses demonstrate the effectiveness of the proposed HOM
model implementation to ensure optimal convergence in both elastic and
softening regime. Furthermore, the proposed approach allows the natural
formulation of a localization limiter able to prevent strain localization and
spurious mesh sensitivity known to be pathological issues for typical local
strain-softening constitutive equations.


title:
Thermodynamics and Phase transition of Schwarzschild black hole in
  Gravity's Rainbow

abstract:
  The Planck length and Planck energy should be taken as invariant scales are
in agreement with various theories of quantum gravity. In this scenario, the
original general relativity can be changed to the so-called gravity's rainbow
which produces significant modifications to the black holes' evolution. In this
paper, using two kinds of rainbow functions, we investigate the thermodynamics
and the phase transition of Schwarzschild black hole in the context of
gravity's rainbow theory. Firstly, with the help of the Heisenberg uncertainty
principle, we calculate the modified Hawking temperature. Then, based on this
modification, we derive the local temperature, free energy and other
thermodynamic quantities in an isothermal cavity. Finally, the critical
behavior, the thermodynamic stability and phase transition of the rainbow
Schwarzschild black hole are analyzed. It turns out that our results are
different from the those of Hawking-Page phase transition. Meanwhile, it is
found that there are many similarities and differences between rainbow
functions I case and rainbow functions II.


title: Global cross-calibration of Landsat spectral mixture models

abstract:
  Data continuity for the Landsat program relies on accurate cross-calibration
among sensors. The Landsat 8 OLI has been shown to exhibit superior performance
to the sensors on Landsats 4-7 with respect to radiometric calibration, signal
to noise, and geolocation. However, improvements to the positioning of the
spectral response functions on the OLI have resulted in known biases for
commonly used spectral indices because the new band responses integrate
absorption features differently from previous Landsat sensors. The objective of
this analysis is to quantify the impact of these changes on linear spectral
mixture models that use imagery collected by different Landsat sensors. The
2013 underflight of Landsat 7 and 8 provides an opportunity to cross calibrate
the spectral mixing spaces of the ETM+ and OLI sensors using near-simultaneous
acquisitions from a wide variety of land cover types worldwide. We use
80,910,343 pairs of OLI and ETM+ spectra to characterize the OLI spectral
mixing space and perform a cross-calibration with ETM+. This new global
collection of Landsat spectra spans a greater spectral diversity than those
used in prior studies and the resulting Substrate, Vegetation, and Dark (SVD)
spectral endmembers (EMs) supplant prior global Landsat EMs. We find only minor
(-0.01 < u < 0.01) differences between SVD fractions unmixed using
sensor-specific EMs. RMS misfit fractions are also small (<98% of pixels with
<5% RMSE), in accord with past studies. Finally, vegetation is used as an
example to illustrate the empirical and theoretical relationship between
commonly used spectral indices and subpixel fractions. SVD fractions unmixed
using global EMs thus provide easily computable, linearly scalable, physically
based measures of subpixel land cover which can be compared accurately across
the entire Landsat 4-8 archive without introducing any additional cross-sensor
corrections.


title:
Charged Cylindrical Polytropes with Generalized Polytropic Equation of
  State

abstract:
  We study the general formalism of polytropes in relativistic regime with
generalized polytropic equations of state in the vicinity of cylindrical
symmetry. We take charged anisotropic fluid distribution of matter with
conformally flat condition for the development of general framework of
polytropes. We discussed the stability of the model by Whittaker formula and
concluded that one of the developed model is physically viable.


title:
The habitability of Proxima Centauri b II. Possible climates and
  Observability

abstract:
  Radial velocity monitoring has found the signature of a $M \sin i =
1.3$~M$_\oplus$ planet located within the Habitable Zone (HZ) of Proxima
Centauri \citep{Anglada16}. Despite a hotter past and an active host star the
planet Proxima~b could have retained enough volatiles to sustain surface
habitability \citep{Ribas2016}. Here we use a 3D Global Climate Model (GCM) to
simulate Proxima b's atmosphere and water cycle for its two likely rotation
modes (1:1 and 3:2 spin-orbit resonances) while varying the unconstrained
surface water inventory and atmospheric greenhouse effect. We find that a broad
range of atmospheric compositions allow surface liquid water. On a
tidally-locked planet with sufficient surface water inventory, liquid water is
always present, at least in the substellar region. With a non-synchronous
rotation, this requires a minimum greenhouse warming ($\sim$10~mbar of CO$_2$
and 1~bar of N$_2$). If the planet is dryer, $\sim$0.5~bar/1.5~bars of CO$_2$
(respectively for asynchronous/synchronous rotation) suffice to prevent the
trapping of any arbitrary small water inventory into polar/nightside ice caps.
We produce reflection/emission spectra and phase curves for the simulated
climates. We find that atmospheric characterization will be possible by direct
imaging with forthcoming large telescopes. The angular separation of $7
\lambda/D$ at 1~$\mu$m (with the E-ELT) and a contrast of $\sim$10$^{-7}$ will
enable high-resolution spectroscopy and the search for molecular signatures,
including H$_2$O, O$_2$, and CO$_2$. The observation of thermal phase curves
can be attempted with JWST, thanks to a contrast of $2\times10^{-5}$ at
10~$\mu$m. Proxima~b will also be an exceptional target for future IR
interferometers. Within a decade it will be possible to image Proxima~b and
possibly determine whether this exoplanet's surface is habitable.


title:
Efficient algorithms for computing the Euler-Poincar\'e characteristic
  of symmetric semi-algebraic sets

abstract:
  Let $\mathrm{R}$ be a real closed field and $\mathrm{D} \subset \mathrm{R}$
an ordered domain. We consider the algorithmic problem of computing the
generalized Euler-Poincar\'e characteristic of real algebraic as well as
semi-algebraic subsets of $\mathrm{R}^k$, which are defined by symmetric
polynomials with coefficients in $\mathrm{D}$. We give algorithms for computing
the generalized Euler-Poincar\'e characteristic of such sets, whose
complexities measured by the number the number of arithmetic operations in
$\mathrm{D}$, are polynomially bounded in terms of $k$ and the number of
polynomials in the input, assuming that the degrees of the input polynomials
are bounded by a constant. This is in contrast to the best complexity of the
known algorithms for the same problems in the non-symmetric situation, which
are singly exponential. This singly exponential complexity for the latter
problem is unlikely to be improved because of hardness result
($\#\mathbf{P}$-hardness) coming from discrete complexity theory.


title: Extremal metrics for Laplace eigenvalues in perturbed conformal classes

abstract:
  We prove that in many cases the existence of an extremal metric for some
Laplace eigenvalue in a conformal class allows to find extremal metrics in
conformal classes close by. As a consequence and as part of the arguments we
obtain perturbed harmonic maps with constant density.


title: $E^2$-MAC: Energy Efficient Medium Access for Massive M2M Communications

abstract:
  In this paper, we investigate energy-efficient clustering and medium access
control (MAC) for cellular-based M2M networks to minimize device energy
consumption and prolong network battery lifetime. First, we present an accurate
energy consumption model that considers both static and dynamic energy
consumptions, and utilize this model to derive the network lifetime. Second, we
find the cluster size to maximize the network lifetime and develop an
energy-efficient cluster-head selection scheme. Furthermore, we find feasible
regions where clustering is beneficial in enhancing network lifetime. We
further investigate communications protocols for both intra- and inter-cluster
communications. While inter-cluster communications use conventional cellular
access schemes, we develop an energy-efficient and load-adaptive multiple
access scheme, called n-phase CSMA/CA, which provides a tunable tradeoff
between energy efficiency, delay, and spectral efficiency of the network. The
simulation results show that the proposed clustering, cluster-head selection,
and communications protocol design outperform the others in energy saving and
significantly prolong the lifetimes of both individual nodes and the whole M2M
network.


title: A model for reducing the angulon operator

abstract:
  We propose a mathematical model for the recently introduced angulon. In our
formulation, the angulon operator is decomposable relative to the field of
Hilbert spaces over the probability measure space. That is, we transfer the
population of phonons from the inner structure of the many-body Hamiltonian to
the definition of the measure. We do not compute the measure itself. However,
we demonstrate that the approach allows us to perform angular reduction thereby
considerably simplifying the spectral analysis.

categories: math-ph cond-mat.quant-gas math.MP quant-ph


title:
Operation regimes, gain dynamics and highly stable operation points of
  Ho:YLF regenerative amplifiers

abstract:
  We present a comprehensive study of laser pulse amplification with respect to
operation regimes, gain dynamics, and highly stable operation points of Ho:YLF
regenerative amplifiers (RAs). The findings are expected to be more generic
than for this specific case. Operation regimes are distinguished with respect
to pulse energy and the appearance of pulse instability, and are studied as a
function of the repetition rate, seed energy, and pump intensity. The
corresponding gain dynamics are presented, identifying highly stable operation
points related to high gain build -up during pumping and high gain depletion
during pulse amplification. These operation points are studied numerically and
experimentally as a function of several parameters, thereby achieving, for our
Ho:YLF RA, highly stable output pulses with measured fluctuations of only 0.19%
(standard deviation).


title: On Friedrichs Model with Two Continuum States

abstract:
  The Friedrichs model with one discrete state coupled to more than one
continuum is studied. The exact eigenstates for the full Hamiltonian can be
solved explicitly. The discrete state is found to generate more than one
virtual state pole or more than one pair of resonance poles in different
Riemann sheets in different situations. The form factors could also generate
new states on different sheets. All these states can appear in the generalized
completeness relation.


title: Friends of 12

abstract:
  A friend of 12 is a positive integer different from 12 with the same
abundancy index. By enlarging the supply of methods of Ward [1], it is shown
that (i) if n is an odd friend of 12, then n=m^2, where m has at least 5
distinct prime factors, including 3, and (ii) if n is an even friend of 12
other than 234, then n=2*(q^e)*(m^2), in which q is a prime greater than or
equal to 29, e is a positive integer, and both q and e are congruent to 1 mod
4, and m has at least 3 distinct odd prime factors, one of which is 3, and the
other, none equal to q, are greater than or equal to 29.


title:
Study of W and Z Boson Production in Proton-Lead Collisions at the LHC
  with KP Nuclear Parton Distributions

abstract:
  We present a detailed study of the (pseudo)rapidity distributions of massive
vector bosons produced in p+p and p+Pb collisions at the LHC within the
next-to-leading order approximation in perturbative quantum chromodynamics. In
particular, we discuss the impact of different cold nuclear matter effects on
this process using the nuclear parton distributions calculated from the
microscopic model developed by Kulagin and Petti (KP). This model was
successfully applied to study nuclear effects in the deep-inelastic scattering
and the Drell-Yan reactions off various (fixed) target nuclei. Results are
compared with the recent CMS and ATLAS p+Pb data with \sqrt{s}=5.02 TeV per two
colliding nucleons. We found an excellent agreement between the predictions of
the KP model and the recent LHC data on W+- and Z0 production in p+Pb
collisions, including the differential cross sections, the forward-backward
asymmetries, and W charge asymmetry. We also discuss the sensitivity of the
current and future LHC data to the underlying mechanisms responsible for the
nuclear modifications of parton density functions.


title:
A 1.9 Earth radius rocky planet and the discovery of a non-transiting
  planet in the Kepler-20 system

abstract:
  Kepler-20 is a solar-type star (V = 12.5) hosting a compact system of five
transiting planets, all packed within the orbital distance of Mercury in our
own Solar System. A transition from rocky to gaseous planets with a planetary
transition radius of ~1.6 REarth has recently been proposed by several
publications in the literature (Rogers 2015;Weiss & Marcy 2014). Kepler-20b (Rp
~ 1.9 REarth) has a size beyond this transition radius, however previous mass
measurements were not sufficiently precise to allow definite conclusions to be
drawn regarding its composition. We present new mass measurements of three of
the planets in the Kepler-20 system facilitated by 104 radial velocity
measurements from the HARPS-N spectrograph and 30 archival Keck/HIRES
observations, as well as an updated photometric analysis of the Kepler data and
an asteroseismic analysis of the host star (MStar = 0.948+-0.051 Msun and Rstar
= 0.964+-0.018 Rsun). Kepler-20b is a 1.868+0.066-0.034 REarth planet in a 3.7
day period with a mass of 9.70+1.41-1.44 MEarth resulting in a mean density of
8.2+1.5-1.3 g/cc indicating a rocky composition with an iron to silicate ratio
consistent with that of the Earth. This makes Kepler-20b the most massive
planet with a rocky composition found to date. Furthermore, we report the
discovery of an additional non-transiting planet with a minimum mass of
19.96+3.08-3.61 MEarth and an orbital period of ~34 days in the gap between
Kepler-20f (P ~ 11 days) and Kepler-20d (P ~ 78 days).


title:
Active-to-absorbing phase transition subjected to the velocity
  fluctuations in the frozen limit case

abstract:
  The directed bond percolation process is studied in the presence of com-
pressible velocity fluctuations with long-range correlations. We discuss a
construction of a field theoretic action and a way of obtaining its large scale
properties using the perturbative renormalization group. The most interest- ing
results for the frozen velocity limit are given.


title:
Global well-posedness of the derivative nonlinear Schr\"odinger equation
  with periodic boundary condition in $H^{\frac12}$

abstract:
  We establish the global well-posedness of the derivative nonlinear
Schr\"odinger equation with periodic boundary condition in the Sobolev space
$H^{\frac12}$, provided that the mass of initial data is less than $4\pi$. This
result matches the one by Miao, Wu, and Xu and its recent mass threshold
improvement by Guo and Wu in the non-periodic setting. Below $H^{\frac12}$, we
show that the uniform continuity of the solution map on bounded subsets of
$H^s$ does not hold, for any gauge equivalent equation.


title: Thermal Tomography of Asteroid Surface Structure

abstract:
  Knowledge of the surface thermal inertia of an asteroid can provide insight
into surface structure: porous material has a lower thermal inertia than rock.
We develop a means to estimate thermal inertia values of asteroids and use it
to show that thermal inertia appears to increase with spin period in the case
of main-belt asteroids (MBAs). Similar behavior is found on the basis of
thermophysical modeling for near-Earth objects (NEOs). We interpret our results
in terms of rapidly increasing material density and thermal conductivity with
depth, and provide evidence that thermal inertia increases by factors of 10
(MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent
with a very general picture of rapidly changing material properties in the
topmost regolith layers of asteroids and have important implications for
calculations of the Yarkovsky effect, including its perturbation of the orbits
of potentially hazardous objects and those of asteroid family members after the
break-up event. Evidence of a rapid increase of thermal inertia with depth is
also an important result for studies of the ejecta-enhanced momentum transfer
of impacting vehicles ("kinetic impactors") in planetary defense.


title: Machian strings as an alternative to dark energy

abstract:
  The expansion history of the Universe is calculated using a simple model in
which the entire rest mass energy of a massive particle is distributed
throughout the set of Machian strings connecting it to all the other particles
in the observable Universe. With the assumption that the energy in a Machian
string has the form of positive Newtonian potential energy, the deceleration
rates in the radiation and matter eras are exactly the same as in the
conventional $\Lambda$CDM model. The transition from deceleration to
acceleration at the present time is obtained by making the simplest possible
modification of the Newtonian potential energy to represent the effect of the
cosmological expansion. The effective dark matter and dark energy densities are
calculated in terms of the speed of the Hubble flow at the radius of the
observable Universe.


title: Machian strings as an alternative to dark matter

abstract:
  Dark matter effects may be attributed to interactions between the Machian
strings connecting every pair of elementary particles in the observable
Universe. A simple model for the interaction between Machian strings is
proposed. In the early Universe, the Machian strings of a density perturbation
had a spherically symmetric distribution and the interaction with the Machian
strings of a test particle is found to give a multiple of the Newtonian
gravitational acceleration. In a strong gravitational field, the interaction
between Machian strings tends to a constant limit in order to ensure the
absence of dark matter effects in the Solar System. Dark matter effects on a
galactic scale may be attributed to a change in the distribution of the Machian
strings around a galaxy during the process of galaxy formation. The interaction
between the Machian strings of a test mass and the Machian strings of a galaxy
is considered in detail and the MOND phenomenology for galaxy rotation curves
is obtained.


title: Delone Sets: Local Identity and Global Symmetry

abstract:
  In the paper we present a proof of the local criterion for crystalline
structures which generalizes the local criterion for regular systems. A Delone
set is called a crystal if it is invariant with respect to a crystallgraphic
group. So-called locally antipodal Delone sets, i.e. such sets in which all
2R-clusters are centrally symmetrical, are considered. It turns out that the
local antipodal sets have crystalline structure. Moreover, if in a locally
antipodal set all 2R-clusters are the same the set is a regular system, i.e. a
Delone set whose symmetry group operates transitively on the set.


title:
Optical performance of prototype horn-coupled TES bolometer arrays for
  SAFARI

abstract:
  The SAFARI Detector Test Facility is an ultra-low background optical testbed
for characterizing ultra-sensitive prototype horn-coupled TES bolmeters for
SAFARI, the grating spectrometer on board the proposed SPICA satellite. The
testbed contains internal cold and hot black-body illuminators and a light-pipe
for illumination with an external source. We have added reimaging optics to
facilitate array optical measurements. The system is now being used for optical
testing of prototype detector arrays read out with frequency-domain
multiplexing. We present our latest optical measurements of prototype arrays
and discuss these in terms of the instrument performance.


title: Seifert fibrations of lens spaces

abstract:
  We classify the Seifert fibrations of any given lens space L(p,q). We give an
algorithmic construction of a Seifert fibration of L(p,q) over the base
orbifold S^2(m,n) with the coprime parts of m and n arbitrarily prescribed.
This algorithm produces all possible Seifert fibrations, and the equivalences
between the resulting Seifert fibrations are described completely. Also, we
show that all Seifert fibrations are equivalent to certain standard models.


title: Effect of Incomplete Meta-dataset on Average Ranking Method

abstract:
  One of the simplest metalearning methods is the average ranking method. This
method uses metadata in the form of test results of a given set of algorithms
on given set of datasets and calculates an average rank for each algorithm. The
ranks are used to construct the average ranking. We investigate the problem of
how the process of generating the average ranking is affected by incomplete
metadata including fewer test results. This issue is relevant, because if we
could show that incomplete metadata does not affect the final results much, we
could explore it in future design. We could simply conduct fewer tests and save
thus computation time. In this paper we describe an upgraded average ranking
method that is capable of dealing with incomplete metadata. Our results show
that the proposed method is relatively robust to omission in test results in
the meta datasets.


title: Yuri Safarov (1958-2015)

abstract:
  This is the editor's preface to the special issue of Journal of Spectral
Theory, in memory of Yuri Safarov.


title: Additive Energy and Irregularities of Distribution

abstract:
  We consider strictly increasing sequences $\left(a_{n}\right)_{n \geq 1}$ of
integers and sequences of fractional parts $\left(\left\{a_{n}
\alpha\right\}\right)_{n \geq 1}$ where $\alpha \in \mathbb{R}$. We show that a
small additive energy of $\left(a_{n}\right)_{n \geq 1}$ implies that for
almost all $\alpha$ the sequence $\left(\left\{a_{n} \alpha\right\}\right)_{n
\geq 1}$ has large discrepancy. We prove a general result, provide various
examples, and show that the converse assertion is not necessarily true.