title:
Generic irreducibilty of Laplace eigenspaces on certain compact Lie
  groups

abstract:
  If $G$ is a compact Lie group endowed with a left invariant metric $g$, then
$G$ acts via pullback by isometries on each eigenspace of the associated
Laplace operator $\Delta_g$. We establish algebraic criteria for the existence
of left invariant metrics $g$ on $G$ such that each eigenspace of $\Delta_g$,
regarded as the real vector space of the corresponding real eigenfunctions, is
irreducible under the action of $G$. We prove that generic left invariant
metrics on the Lie groups
$G=\operatorname{SU}(2)\times\ldots\times\operatorname{SU}(2)\times T$, where
$T$ is a (possibly trivial) torus, have the property just described. The same
holds for quotients of such groups $G$ by discrete central subgroups. In
particular, it also holds for $\operatorname{SO}(3)$, $\operatorname{U}(2)$,
$\operatorname{SO}(4)$.


title:
Fredholm criteria for pseudodifferential operators and induced
  representations of groupoid algebras

abstract:
  We characterize the groupoids for which an operator is Fredholm if, and only
if, its principal symbol and all its boundary restrictions are invertible. A
groupoid with this property is called {\em Fredholm}. Using results on the
Effros-Hahn conjecture, we show that an almost amenable, Hausdorff, second
countable groupoid is Fredholm. Many groupoids, and hence many
pseudodifferential operators appearing in practice, fit into this framework. In
particular, one can use these results to characterize the Fredholm operators on
manifolds with cylindrical and poly-cylindrical ends, on manifolds that are
asymptotically Euclidean or asymptotically hyperbolic, on products of such
manifolds, and on many others. Moreover, we show that the desingularization of
Lie groupoids preserves the class of Fredholm groupoids.

categories: math.OA math-ph math.AP math.FA math.MP math.SP


title:
Finding mixed families of special polynomials associated with Appell
  sequences

abstract:
  In this paper, certain mixed special polynomial families associated with
Appell sequences are introduced and their properties are established. Further,
operational rules providing connections between these families and the known
special polynomials are established, which are used to derive the identities
and results for the members of these new families. Determinantal definitions of
the polynomials associated with Appell family is also derived. The approach
presented is general.


title: Distributed Information-Theoretic Clustering

abstract:
  We study a novel multi-terminal source coding setup motivated by the
biclustering problem. Two separate encoders observe two i.i.d. sequences $X^n$
and $Y^n$, respectively. The goal is to find rate-limited encodings $f(x^n)$
and $g(z^n)$ that maximize the mutual information $I(f(X^n); g(Y^n))/n$. We
discuss connections of this problem with hypothesis testing against
independence, pattern recognition, and the information bottleneck method.
Improving previous cardinality bounds for the inner and outer bounds allows us
to thoroughly study the special case of a binary symmetric source and to
quantify the gap between the inner and the outer bound in this special case.
Furthermore, we investigate a multiple description (MD) extension of the Chief
Operating Officer (CEO) problem with mutual information constraint.
Surprisingly, this MD-CEO problem permits a tight single-letter
characterization of the achievable region.


title: Controlled long-range interactions between Rydberg atoms and ions

abstract:
  We theoretically investigate trapped ions interacting with atoms that are
coupled to Rydberg states. The strong polarizabilities of the Rydberg levels
increases the interaction strength between atoms and ions by many orders of
magnitude, as compared to the case of ground state atoms, and may be mediated
over micrometers. We calculate that such interactions can be used to generate
entanglement between an atom and the motion or internal state of an ion.
Furthermore, the ion could be used as a bus for mediating spin-spin
interactions between atomic spins in analogy to much employed techniques in ion
trap quantum simulation. The proposed scheme comes with attractive features as
it maps the benefits of the trapped ion quantum system onto the atomic one
without obviously impeding its intrinsic scalability. No ground state cooling
of the ion or atom is required and the setup allows for full dynamical control.
Moreover, the scheme is to a large extent immune to the micromotion of the ion.
Our findings are of interest for developing hybrid quantum information
platforms and for implementing quantum simulations of solid state physics.


title:
Jet tomography in heavy-ion collisions -- Challenges, Results, and Open
  Problems

abstract:
  Over the past 30 years, jet observables have proven to provide important
information about the quark-gluon plasma created in heavy-ion collisions. I
review the challenges, results, and open problems of jet physics in heavy-ion
collisions, discussing the main ideas as well as some most recent results
focussing on two major jet observables, the nuclear modification factor and the
high-pT elliptic flow.


title:
Effects of the Number of Active Receiver Channels on the Sensitivity of
  a Reflector Antenna System with a Multi-Beam Wideband Phased Array Feed

abstract:
  A method for accurate modeling of a reflector antenna system with a wideband
phased array feed is presented and used to study the effects of the number of
active antenna elements and associated receiving channels on the receiving
sensitivity of the antenna system. Numerical results are shown for a practical
design named APERTIF that is currently under developed at The Netherlands
Institute for Radio Astronomy (ASTRON).


title:
Partially observed optimal stopping problem for discrete-time Markov
  processes

abstract:
  This paper is dedicated to the investigation of a new numerical method to
approximate the optimal stopping problem for a discrete-time continuous state
space Markov chain under partial observations. It is based on a two-step
discretization procedure based on optimal quantization. First,we discretize the
state space of the unobserved variable by quantizing an underlying reference
measure. Then we jointly discretize the resulting approximate filter and the
observation process. We obtain a fully computable approximation of the value
function with explicit error bounds for its convergence towards the true value
fonction.


title:
Spherically symmetric potential in noncommutative spacetime with a
  compactified extra dimensions

abstract:
  The Schr\"odinger equation of the spherical symmetry quantum models such as
the hydrogen atom problem seems to be analytically non-solvable in higher
dimensions. When we try to compactifying one or several dimensions this
question can maybe solved. This paper stands for the study of the spherical
symmetry quantum models on noncommutative spacetime with compactified extra
dimensions. We provide analytically the resulting spectrum of the hydrogen atom
and Yukawa problem in $4+1$ dimensional noncommutative spacetime in the first
order approximation of noncommutative parameter. The case of higher dimensions
$D\geq 4$ is also discussed.


title: Effects of Dephasing on Spin Lifetime in Ballistic Spin-Orbit Materials

abstract:
  We theoretically investigate spin dynamics in spin-orbit-coupled materials.
In the ballistic limit, the spin lifetime is dictated by dephasing that arises
from energy broadening plus a non-uniform spin precession. For the case of
clean graphene, we find a strong anisotropy with spin lifetimes that can be
short even for modest energy scales, on the order of a few ns. These results
offer deeper insight into the nature of spin dynamics in graphene, and are also
applicable to the investigation of other systems where spin-orbit coupling
plays an important role.


title:
Simple nuclear C*-algebras not equivariantly isomorphic to their
  opposites

abstract:
  We exhibit examples of simple separable nuclear C*-algebras, along with
actions of the circle group and outer actions of the integers, which are not
equivariantly isomorphic to their opposite algebras. In fact, the fixed point
subalgebras are not isomorphic to their opposites. The C*-algebras we exhibit
are well behaved from the perspective of structure and classification of
nuclear C*-algebras: they are unital C*-algebras in the UCT class, with finite
nuclear dimension. One is an AH-algebra with unique tracial state and absorbs
the CAR algebra tensorially. The other is a Kirchberg algebra.


title:
Towards reducing the multidimensionality of OLAP cubes using the
  Evolutionary Algorithms and Factor Analysis Methods

abstract:
  Data Warehouses are structures with large amount of data collected from
heterogeneous sources to be used in a decision support system. Data Warehouses
analysis identifies hidden patterns initially unexpected which analysis
requires great memory and computation cost. Data reduction methods were
proposed to make this analysis easier. In this paper, we present a hybrid
approach based on Genetic Algorithms (GA) as Evolutionary Algorithms and the
Multiple Correspondence Analysis (MCA) as Analysis Factor Methods to conduct
this reduction. Our approach identifies reduced subset of dimensions from the
initial subset p where p'<p where it is proposed to find the profile fact that
is the closest to reference. GAs identify the possible subsets and the Khi
formula of the ACM evaluates the quality of each subset. The study is based on
a distance measurement between the reference and n facts profile extracted from
the Warehouses.


title:
Effective Polyakov loop models for QCD-like theories at finite chemical
  potential

abstract:
  We study genuine finite density effects in QCD-like theories with
three-dimensional Polyakov-loop effective theories for heavy quarks. These are
derived from the full QCD-like theories by combined strong-coupling and hopping
expansions. In particular, we investigate the cold and dense regimes of phase
diagrams where we expect to find Bose-Einstein-condensation of diquark baryons
or a fermionic first-order liquid-gas transition, depending on the gauge group
of the theory. In two-color QCD, for example, we observe evidence of a
continuous zero-temperature transition to finite diquark density when the quark
chemical potential $\mu$ reaches half the diquark mass, i.e. without binding
energy. In G$_2$-QCD we observe, in addition to this "Silver Blaze" onset of
diquark density, a second transition in the density towards an exponential
increase by roughly $3\mu/T$ corresponding to a finite density of
G$_2$-nucleons.


title:
Analysis of receiving sensitivity of multi-beam antenna systems with a
  focal plane array (in Russian)

abstract:
  In this paper, we present a numerical electromagnetic model of a focal plane
array in combination with a multi-channel receiver. Initial experimental
validation results are shown that confirm the expected predictions from the
model.


title: Quantum Trajectory Thermodynamics with Discrete Feedback Control

abstract:
  We employ the quantum jump trajectory approach to construct a systematic
framework to study the thermodynamics at the trajectory level in a
nonequilibrium open quantum system under discrete feedback control. Within this
framework, we derive quantum versions of the generalized Jarzynski equalities,
which are demonstrated in an isolated pseudospin system and a coherently driven
two-level open quantum system. Due to quantum coherence and measurement
backaction, a fundamental distinction from the classical generalized Jarzynski
equalities emerges in the quantum versions, which is characterized by a large
negative information gain reflecting genuinely quantum rare events. A possible
experimental scheme to test our findings in superconducting qubits is
discussed.


title:
Comment on "Atomic structure calculations for F-like tungsten" by S.
  Aggarwal

abstract:
  Recently, S. Aggarwal [Chin. Phys. B 23 (2014) 093203] reported energy
levels, radiative rates and lifetimes for the lowest 60 levels belonging to the
2s$^2$2p$^5$, 2s2p$^6$ and 2s$^2$2p$^4$3$\ell$ configurations of F-like
tungsten. There is no discrepancy for his calculated energies for the levels
and the radiative rates for the limited number of E1 transitions, but the
reported results for lifetimes are highly inaccurate. According to our
calculations, errors in his reported lifetimes are up to 6 orders of magnitude
for several levels. Here we report the correct lifetimes for future comparisons
and applications, and also explain the reason for discrepancies.


title:
On Polya's inequality for torsional rigidity and first Dirichlet
  eigenvalue

abstract:
  Let $\Omega$ be an open set in Euclidean space with finite Lebesgue measure
$|\Omega|$. We obtain some properties of the set function $F:\Omega\mapsto
\R^+$ defined by $$ F(\Omega)=\frac{T(\Omega)\lambda_1(\Omega)}{|\Omega|} ,$$
where $T(\Omega)$ and $\lambda_1(\Omega)$ are the torsional rigidity and the
first eigenvalue of the Dirichlet Laplacian respectively. We improve the
classical P\'olya bound $F(\Omega)\le 1,$ and show that $$F(\Omega)\le 1- \nu_m
T(\Omega)|\Omega|^{-1-\frac2m},$$ where $\nu_m$ depends only on $m$. For any
$m=2,3,\dots$ and $\epsilon\in (0,1)$ we construct an open set
$\Omega_{\epsilon}\subset \R^m$ such that $F(\Omega_{\epsilon})\ge 1-\epsilon$.


title:
Size dependence of thermoelectric power of Au, Pd, Pt nanoclusters
  deposited onto HOPG surface

abstract:
  The paper presents the study of tunnel current-voltage characteristics of Au,
Pd and Pt nanoclusters deposited onto the highly oriented pyrolytic graphite
(HOPG) surface by pulsed laser deposition. The analysis of tunnel
current-voltage characteristics obtained by scanning tunneling spectroscopy
(STS) allowed to recover the thermoelectric power value of nanoclusters. It was
found that the value of thermoelectric power of pulsed laser deposited
nanoclusters depends on nanocluster material and shows qualitative difference
in size dependence for different materials of nanoclusters. Thus,
thermoelectric power value of PLD Pd nanoclusters decreases with increasing of
nanocluster size, while for Au nanoclusters this value increases. The analysis
of the results are discussed.


title:
A Framework for the Adoption of Biometric ATM Authentication in the
  Kenyan Banks

abstract:
  The use of ATMs has become fundamental in the banking industry owing to the
values transacted using these systems and their 24/7 usage. Although several
researchers have studied the role of biometrics in security applications for
financial institutions, no systematic empirical research has been applied to
studying the role of organizational characteristics and contextual factors in
the Kenyan financial sector. This study sought to develop a framework for the
adoption of biometric ATMs in the Kenyan banking sector, apply the developed
framework to study factors influencing adoption of biometric ATM authentication
and validate the developed conceptual framework. A survey was used to collect
quantitative data from the ATM users which was then analysed using factor
analysis and multiple regression analysis. The study established that
performance expectancy, effort expectancy, social influence and user privacy
were key determinants for biometric ATMs acceptance, adoption and usage. The
study further demonstrated that age, gender and experience were moderating
factors on effort expectancy with experience further moderating performance
expectancy, effort expectancy, social influence and user privacy. Key words:
Key words: framework, adoption, authentication, financial institutions


title: Deep Exploration via Bootstrapped DQN

abstract:
  Efficient exploration in complex environments remains a major challenge for
reinforcement learning. We propose bootstrapped DQN, a simple algorithm that
explores in a computationally and statistically efficient manner through use of
randomized value functions. Unlike dithering strategies such as epsilon-greedy
exploration, bootstrapped DQN carries out temporally-extended (or deep)
exploration; this can lead to exponentially faster learning. We demonstrate
these benefits in complex stochastic MDPs and in the large-scale Arcade
Learning Environment. Bootstrapped DQN substantially improves learning times
and performance across most Atari games.


title:
The SOPHIE search for northern extrasolar planets. X. Detection and
  characterization of giant planets by the dozen

abstract:
  We present new radial velocity measurements of eight stars secured with the
spectrograph SOPHIE at the 193-cm telescope of the Haute-Provence Observatory
allowing the detection and characterization of new giant extrasolar planets.
The host stars are dwarfs of spectral types between F5 and K0 and magnitudes
between 6.7 and 9.6; the planets have minimum masses M_p sin i between 0.4 to
3.8 M_Jup and orbital periods of several days to several months. The data allow
only single planets to be discovered around the first six stars (HD143105,
HIP109600, HD35759, HIP109384, HD220842, and HD12484), but one of them shows
the signature of an additional substellar companion in the system. The seventh
star, HIP65407, allows the discovery of two giant planets, just outside the
12:5 resonance in weak mutual interaction. The last star, HD141399, was already
known to host a four-planetary system; our additional data and analyses allow
new constraints to be put on it. We present Keplerian orbits of all systems,
together with dynamical analyses of the two multi-planetary systems. HD143105
is one of the brightest stars known to host a hot Jupiter, which could allow
numerous follow-up studies to be conducted despite this is not a transiting
system. The giant planets HIP109600b, HIP109384b, and HD141399c are located in
the habitable zone of their host star.


title: Competition numbers of planar graphs

abstract:
  In this paper, we relate the competition number of a graph to its edge clique
cover number by presenting a tight inequality $k(G) \ge
\theta_e(G)-|V(G)|+\widetilde{k}(G)$ where $\theta_e(G)$, $k(G)$, and
$\widetilde{k}(G)$ are the edge clique cover number, the competition number,
and the co-competition number of a graph $G$, respectively. By utilizing this
inequality and a notion of competition-effective edge clique cover, we obtain
some meaningful results on competition numbers of planar graphs.


title: Diffusion of a Brownian ellipsoid in a force field

abstract:
  We calculate the effective long-term convective velocity and dispersive
motion of an ellipsoidal Brownian particle in three dimensions when it is
subjected to a constant external force. This long-term motion results as a
"net" average behavior from the particle rotation and translation on short time
scales. Accordingly, we apply a systematic multi-scale technique to derive the
effective equations of motion valid on long times. We verify our theoretical
results by comparing them to numerical simulations.


title: Stable discontinuous Galerkin FEM without penalty parameters

abstract:
  We propose a modified local discontinuous Galerkin (LDG) method for
second--order elliptic problems that does not require extrinsic penalization to
ensure stability. Stability is instead achieved by showing a discrete
Poincar\'e--Friedrichs inequality for the discrete gradient that employs a
lifting of the jumps with one polynomial degree higher than the scalar
approximation space. Our analysis covers rather general simplicial meshes with
the possibility of hanging nodes.


title:
A Semi-Lagrangian Scheme with Radial Basis Approximation for Surface
  Reconstruction

abstract:
  We propose a Semi-Lagrangian scheme coupled with Radial Basis Function
interpolation for approximating a curvature-related level set model, which has
been proposed by Zhao et al. in \cite{ZOMK} to reconstruct unknown surfaces
from sparse, possibly noisy data sets. The main advantages of the proposed
scheme are the possibility to solve the level set method on unstructured grids,
as well as to concentrate the reconstruction points in the neighbourhood of the
data set, with a consequent reduction of the computational effort. Moreover,
the scheme is explicit. Numerical tests show the accuracy and robustness of our
approach to reconstruct curves and surfaces from relatively sparse data sets.


title:
Multi-beaming propertieis of reflector antennas used in radio telescopes
  with wide field of view

abstract:
  The given work is devoted to the modern developments in the field of radio
astronomy instrumentation. In particular, the sensitivity of the multi-beam
reflector radio telescope which is fed by phased array (PAF) is considered.
Using PAF as reflector feed allows obtaining wide and continuous field of view
(FOV) of the telescope. This has several advantages with compare to
horn-cluster feeds which are described in this work. The sensitivity inside
whole FOV was computed using three different beamforming schemes.


title: Sharp thresholds for half-random games II

abstract:
  We study biased Maker-Breaker positional games between two players, one of
whom is playing randomly against an opponent with an optimal strategy. In this
work we focus on the case of Breaker playing randomly and Maker being "clever".
The reverse scenario is treated in a separate paper. We determine the sharp
threshold bias of classical games played on the edge set of the complete graph
$K_n$, such as connectivity, perfect matching, Hamiltonicity, and minimum
degree-$1$. In all of these games, the threshold is equal to the trivial upper
bound implied by the number of edges needed for Maker to occupy a winning set.
Moreover, we show that the clever Maker can not only win against an
asymptotically optimal bias, but can do so very fast, wasting only
logarithmically many moves (while the winning set sizes are linear in $n$).


title: srsLTE: An Open-Source Platform for LTE Evolution and Experimentation

abstract:
  Testbeds are essential for experimental evaluation as well as for product
development. In the context of LTE networks, existing testbed platforms are
limited either in functionality and/or extensibility or are too complex to
modify and customise. In this work we present srsLTE, an open-source platform
for LTE experimentation designed for maximum modularity and code reuse and
fully compliant with LTE Release 8. We show the potential of the srsLTE library
by extending the baseline code to allow LTE transmissions in the unlicensed
bands and coexistence with WiFi. We also expand previous results on this
emerging research area by showing how different vendor-specific mechanisms in
WiFi cards might affect coexistence.


title: Content Delivery in Erasure Broadcast Channels with Cache and Feedback

abstract:
  We study a content delivery problem in a K-user erasure broadcast channel
such that a content providing server wishes to deliver requested files to
users, each equipped with a cache of a finite memory. Assuming that the
transmitter has state feedback and user caches can be filled during off-peak
hours reliably by the decentralized content placement, we characterize the
achievable rate region as a function of the memory sizes and the erasure
probabilities. The proposed delivery scheme, based on the broadcasting scheme
by Wang and Gatzianas et al., exploits the receiver side information
established during the placement phase. Our results can be extended to
centralized content placement as well as multi-antenna broadcast channels with
state feedback.


title: Non-Boltzmann Ensembles and Monte Carlo Simulation

abstract:
  Boltzmann sampling based on Metropolis algorithm has been extensively used
for simulating a canonical ensemble. An estimate of a mechanical property, like
energy, of an equilibrium system, can be made by averaging over a large number
microstates generated by Boltzmann Monte Carlo methods. However, a thermal
property like entropy is not easily accessible to these methods. The reason is
simple. We can assign a numerical value for energy to each microstate. But we
can not assign a numerical value for entropy, to a microstate. Entropy is not a
property associated with any single microstate.It is a collective property of
allthe microstates. Toward calculating entropy and other thermal properties, a
non-Boltzmann Monte Carlo technique called Umbrella sampling was proposed in
the mid-seventies (of the last century). Umbrella sampling has since undergone
several metamorphoses and we have now, multi-canonical Monte Carlo, entropic
sampling, flat histogram methods, Wang-Landau algorithm {\it etc.} This class
of methods generates non-Boltzmann ensembles which are un-physical. However,
physical quantities can be calculated by un-weighting of the microstates of the
entropic ensemble, followed by re-weighting to the desired physical ensemble.In
this talk I shall tellyou of a few non-Boltzmann Monte Carlo methods with
emphasis on recent developments.


title: Symmetry breaking in hexagonal and cubic polymorphs of BaTiO3

abstract:
  BaTiO3 appears in cubic and hexagonal variants, both of which are
centrosymmetric. Samples of cubic BaTiO3 are known to exhibit breaking of the
centric symmetry locally and globally. It has been proposed that the local
symmetry breaking originates in polar regions, the precursors of the
ferroelectric phase. Origins of the macroscopic symmetry breaking, which are
not well understood, have been previously tentatively correlated with
inhomogeneities in the samples, such as strain gradients that may align or
redistribute objects such as charged point defects or polar regions making
material macroscopically polar. No such data are available for BaTiO3 with
hexagonal symmetry. We compare dielectric, elastic, and pyroelectric properties
of the two materials in polycrystalline form. In contrast to cubic BaTiO3,
hexagonal BaTiO3 does not exhibit macroscopic pyroelectric response at room
temperature. This is consistent with apparent absence of polar regions in the
hexagonal material and the fact that in hexagonal BaTiO3 strain rather then
polarization is the order parameter for the phase transition into
ferroelectric-ferroelastic phase. The thermally stimulated currents measured in
hexagonal and cubic BaTiO3, however, show that both materials exhibit
noncentric macroscopic symmetry. This result supports the idea that extrinsic
factors such as strain gradients, which are apparently common for both
materials, may break the macroscopic symmetry, which may then lead to alignment
and redistribution of polar regions or charged defects.


title:
Modeling and optimization of the antenna system with focal plane array
  for the new generation radio telescopes with wide field of view

abstract:
  The model of the reflector antenna system with focal plane array, low-noise
amplifier and beamformer is developed in the work. The beamformer strategy is
suggested to reduce the receiving sensitivity ripple inside field of view of
the telescope, while the sensitivity itself drops slightly (less than 10%). The
system APERTIF (which is currently under development in Netherlands Institute
For Radioastronomy, ASTRON) has been analyzed using developed model, and
numerical results are presented. The obtained numerical results have been
verified experimentally in anechoic chamber as well as on one of the dishes of
the Westerbork Synthesis Radio Telescope (all measurements have been done in
ASTRON).


title: Structures of General Relativity in Dilaton-Maxwell Electrodynamics

abstract:
  It is shown that electro (magneto) static sector of Maxwell's electrodynamics
coupled to the dilaton field in a string theory form possesses the symmetry
group of the stationary General Relativity in vacuum. Performing the Ernst
formalism, we develope a technique for generation of exact solutions in this
modified electrodynamics on the base of the normalized Ehlers symmetry
transformation. In the electrostatic case, we construct and study a general
class of spherically symmetric solutions that describes a point-like sourse of
the Coulomb type. It is shown that this source is characterized by asymptotical
freedom of the electrostatic interaction at short distances. Also it is
established that the total electrostatic energy of this source is finite and
inversely proportional to the dilaton-Maxwell coupling constant.


title: Beta-Decay Correlations in the LHC Era

abstract:
  Neutron and nuclear beta decay correlation coefficients are linearly
sensitive to the exotic scalar and tensor interactions that are not included in
the Standard Model. The proposed experiment will measure simultaneously 11
neutron correlation coefficients ($a$, $A$, $B$, $D$, $H$, $L$, $N$, $R$, $S$,
$U$, $V$) where 5 of them ($H$, $L$, $S$, $U$, $V$) were never addressed
before. Silicon pixel detectors are considered as promising alternative to
multi-wire gas chambers devoted for electron tracking in the original setup.
The expected sensitivity limits for $\epsilon_S$ and $\epsilon_T$ -- EFT
parameters describing the scalar and tensor contributions to be extracted from
the transverse electron polarization related coefficients $H$, $L$, $N$, $R$,
$S$, $U$, $V$ are discussed.


title: Singularity-free interaction in dilaton-Maxwell electrodynamics

abstract:
  An effective potential is created for the dynamics of a test particle, which
preserves dilatation symmetry for nonlinear static dilaton-Maxwell background.
It is found that the central interaction in this theory is regular everywhere,
and that the theory is asymptotically free at short distances and that it has a
Coulomb properties at great distances from the source. It is shown that static
and spherically symmetric source, behaves like a soliton: it has the finite
energy characteristics that are inversely proportional to the dilaton-Maxwell
coupling constant.


title: Incircular nets and confocal conics

abstract:
  We consider congruences of straight lines in a plane with the combinatorics
of the square grid, with all elementary quadrilaterals possessing an incircle.
It is shown that all the vertices of such nets (we call them incircular or
IC-nets) lie on confocal conics.
  Our main new results are on checkerboard IC-nets in the plane. These are
congruences of straight lines in the plane with the combinatorics of the square
grid, combinatorially colored as a checkerboard, such that all black coordinate
quadrilaterals possess inscribed circles. We show how this larger class of
IC-nets appears quite naturally in Laguerre geometry of oriented planes and
spheres, and leads to new remarkable incidence theorems. Most of our results
are valid in hyperbolic and spherical geometries as well. We present also
generalizations in spaces of higher dimension, called checkerboard IS-nets. The
construction of these nets is based on a new 9 inspheres incidence theorem.


title: Group Representations on Reflexive Spaces

abstract:
  For weighted group convoltion measure algebra we construct a representation
on reflexsive space.


title: Medium polarization in asymmetric nuclear matter

abstract:
  The influence of the core polarization on the effective nuclear interaction
of asymmetric nuclear matter is calculated in the framework of the induced
interaction theory. The strong isospin dependence of the density and spin
density fluctuations is studied along with the interplay between the neutron
and proton core polarizations. Moving from symmetric nuclear matter to pure
neutron matter the crossover of the induced interaction from attractive to
repulsive in the spin singlet state is determined as a function of the isospin
imbalance.The density range in which it occurs is also determined. For the spin
triplet state the induced interaction turns out to be always repulsive. The
implications of the results for the neutron star superfluid phases are shortly
discussed.


title:
Wind mass transfer in S-type symbiotic binaries II. Indication of wind
  focusing

abstract:
  Context. The wind mass transfer from a giant to its white dwarf companion in
symbiotic binaries is not well understood. For example, the efficiency of wind
mass transfer of the canonical Bondi-Hoyle accretion mechanism is too low to
power the typical luminosities of the accretors. However, recent observations
and modelling indicate a considerably more efficient mass transfer in symbiotic
binaries.
  Aims. We determine the velocity profile of the wind from the giant at the
near-orbital-plane region of eclipsing S-type symbiotic binaries EG And and SY
Mus, and derive the corresponding spherical equivalent of the mass-loss rate.
With this approach, we indicate the high mass transfer ratio.
  Methods. We achieved this aim by modelling the observed column densities
taking into account ionization of the wind of the giant, whose velocity profile
is derived using the inversion of Abel's integral operator for the hydrogen
column density function.
  Results. Our analysis revealed the spherical equivalent of the mass-loss rate
from the giant to be a few times 10^{-6}M_{Sun}/yr, which is a factor of >=10
higher than rates determined by methods that do not depend on the line of
sight. This discrepancy rules out the usual assumption that the wind is
spherically symmetric. As our values were derived from near-orbital-plane
column densities, these values can be a result of focusing the wind from the
giant towards the orbital plane.
  Conclusions. Our findings suggests that the wind from giants in S-type
symbiotic stars is not spherically symmetric, since it is enhanced at the
orbital plane and, thus, is accreted more effectively onto the hot component.


title: Collective behavior of strongly confined suspensions of squirmers

abstract:
  We run numerical simulations of strongly confined suspensions of model
spherical swimmers called "squirmers". Because of the confinement, the
Stokeslet dipoles generated by the particles are quickly screened and the
far-field flow is dominated by the source dipole for all the different kinds of
squirmers. However, we show that the collective behavior of the suspension
still depends on the self-propelling mechanism of the swimmers as polar states
can only be observed for neutral squirmers. We demonstrate that the near-field
hydrodynamic interactions play a crucial role in the alignment of the
orientation vectors of spherical particles. Moreover, we point out that the
enstrophy and the fluid fluctuations of an active suspension also depend on the
nature of the squirmers.


title:
Degree growth of polynomial automorphisms and birational maps: some
  examples

abstract:
  We provide the existence of new degree growths in the context of polynomial
automorphisms of $\mathbb{C}^k$: if $k$ is an integer $\geq 3$, then for any
$\ell\leq \left[\frac{k-1}{2}\right]$ there exist polynomial automorphisms $f$
of $\mathbb{C}^k$ such that $\mathrm{deg}\, f^n\sim n^\ell$. We also give
counter-examples in dimension $k\geq 3$ to some classical properties satisfied
by polynomial automorphisms of $\mathbb{C}^2$.
  We provide the existence of new degree growths in the context of birational
maps of $\mathbb{P}^k_\mathbb{C}$: assume $k\geq 3$; forall $0\leq\ell\leq k$
there exist birational maps $\phi$ of $\mathbb{P}^k_\mathbb{C}$ such that
$\mathrm{deg}\, \phi^n\sim n^\ell$.


title: Optimal shortcuts for atomic transport in anharmonic traps

abstract:
  We design optimal trajectories to transport cold atoms in anharmonic traps,
combining invariant-based inverse engineering, perturbation theory, and optimal
control theory. The anharmonic perturbation energy is minimized constraining
the maximally allowed relative displacement between the trap center and the
atom.


title: The pseudo-fundamental group-scheme

abstract:
  Let $X$ be any scheme defined over a Dedekind scheme $S$ with a given section
$x\in X(S)$. We prove the existence of a pro-finite $S$-group scheme
$\aleph(X,x)$ and a universal $\aleph(X,x)$-torsor dominating all the
pro-finite pointed torsors over $X$. Though $\aleph(X,x)$ may not be unique in
general it still can provide useful information in order to better understand
$X$. In a similar way we prove the existence of a pro-algebraic $S$-group
scheme $\aleph^{\rm alg}(X,x)$ and a $\aleph^{\rm alg}(X,x)$-torsor dominating
all the pro-algebraic and affine pointed torsors over $X$. The case where $X\to
S$ has no sections is also considered.


title:
On the existence of a local quasi hidden variable (LqHV) model for each
  N-qudit state and the maximal quantum violation of Bell inequalities

abstract:
  We specify the local quasi hidden variable (LqHV) model reproducing the
probabilistic description of all N-partite joint von Neumann measurements on an
N-qudit state. Via this local probability model, we derive a new upper bound on
the maximal violation by an N-qudit state of N-partite Bell inequalities of any
type (either on correlation functions or on joint probabilities) for S
observables per site. This new upper bound not only improves for all N, S and d
the corresponding results available for general Bell inequalities in the
literature but also, for the N-qubit case with two observables per site,
reduces exactly to the attainable upper bound known for quantum violations of
correlation 2x...x2-setting Bell inequalities in a dichotomic case.


title: Monitoring Akkuyu Nuclear Reactor Using Antineutrino Flux Measurement

abstract:
  We present a simulation-based study for monitoring Akkuyu Nuclear Power
Plant's activity using antineutrino flux originating from the reactor core. A
water Cherenkov detector has been designed and optimization studies have been
performed using Geant4 simulation toolkit. A first study for the design of a
monitoring detector facility for Akkuyu Nuclear Power Plant is discussed in
this paper.


title:
Ferromagnetic Cluster Glass Phase Embedded in a Paramagnetic and
  Metallic Host in Non-uniform Magnetic System CaRu_{1-x}Sc_{x}O_{3}

abstract:
  We have investigated both static and dynamic magnetic properties of
polycrystalline CaRu$_{1-x}$Sc$_{x}$O$_{3}$ system in order to clarify the role
of Sc ions as a disorder for magnetic ordering. We have observed typical
features of a ferromagnetic cluster glass state below around 40 K: (i) a broad,
frequency-dependent peak in the ac magnetic susceptibility, (ii) a slow
relaxation of the magnetization, and (iii) a continuous increase in the dc
magnetic susceptibility in field cooling process. The composition dependence of
characteristic parameters for the cluster glass state suggests that chemical
segregation can hardly explain the clustering mechanism. We propose a possible
picture that the ferromagnetic clusters are distributed uniformly and form the
glassy state embedded in the paramagnetic and metallic host of CaRuO$_{3}$.


title: Prediction of Dynamical Systems by Symbolic Regression

abstract:
  We study the modeling and prediction of dynamical systems based on
conventional models derived from measurements. Such algorithms are highly
desirable in situations where the underlying dynamics are hard to model from
physical principles or simplified models need to be found. We focus on symbolic
regression methods as a part of machine learning. These algorithms are capable
of learning an analytically tractable model from data, a highly valuable
property. Symbolic regression methods can be considered as generalized
regression methods. We investigate two particular algorithms, the so-called
fast function extraction which is a generalized linear regression algorithm,
and genetic programming which is a very general method. Both are able to
combine functions in a certain way such that a good model for the prediction of
the temporal evolution of a dynamical system can be identified. We illustrate
the algorithms by finding a prediction for the evolution of a harmonic
oscillator based on measurements, by detecting an arriving front in an
excitable system, and as a real-world application, the prediction of solar
power production based on energy production observations at a given site
together with the weather forecast.


title:
Continuity of Hausdorff dimension across generic dynamical Lagrange and
  Markov spectra

abstract:
  Let $\varphi_0$ be a smooth area-preserving diffeomorphism of a compact
surface $M$ and let $\Lambda_0$ be a horseshoe of $\varphi_0$ with Hausdorff
dimension strictly smaller than one. Given a smooth function $f:M\to
\mathbb{R}$ and a small smooth area-preserving perturtabion $\varphi$ of
$\varphi_0$, let $L_{\varphi, f}$, resp. $M_{\varphi, f}$ be the Lagrange,
resp. Markov spectrum of asymptotic highest, resp. highest values of $f$ along
the $\varphi$-orbits of points in the horseshoe $\Lambda$ obtained by
hyperbolic continuation of $\Lambda_0$.
  We show that, for generic choices of $\varphi$ and $f$, the Hausdorff
dimension of the sets $L_{\varphi, f}\cap (-\infty, t)$ vary continuously with
$t\in\mathbb{R}$ and, moreover, $M_{\varphi, f}\cap (-\infty, t)$ has the same
Hausdorff dimension of $L_{\varphi, f}\cap (-\infty, t)$ for all
$t\in\mathbb{R}$.


title: Hyperbolae Are No Hyperbole: Modelling Communities That Are Not Cliques

abstract:
  Cliques are frequently used to model communities: a community is a set of
nodes where each pair is equally likely to be connected. But studying
real-world communities reveals that they have more structure than that. In
particular, the nodes can be ordered in such a way that (almost) all edges in
the community lie below a hyperbola. In this paper we present three new models
for communities that capture this phenomenon. Our models explain the structure
of the communities differently, but we also prove that they are identical in
their expressive power. Our models fit to real-world data much better than
traditional block models or previously-proposed hyperbolic models, both of
which are a special case of our model. Our models also allow for intuitive
interpretation of the parameters, enabling us to summarize the shapes of the
communities in graphs effectively.


title: Hyperbolic localization via shrinking subbundles

abstract:
  We study the Lefschetz fixed point formula for constructible sheaves with
higher-dimensional fixed point sets. We give another proof to the explicit
description of Lefschetz cycles in our previous paper. For this purpose, we
introduce a new notion of shrinking subbundles and describe Lefschetz cycles by
using hyperbolic localization with respect to shrinking subbundles.


title: On the insertion time of random walk cuckoo hashing

abstract:
  Cuckoo Hashing is a hashing scheme invented by Pagh and Rodler. It uses
$d\geq 2$ distinct hash functions to insert items into the hash table. It has
been an open question for some time as to the expected time for Random Walk
Insertion to add items. We show that if the number of hash functions $d=O(1)$
is sufficiently large, then the expected insertion time is $O(1)$ per item.


title:
Weak dispersion for the Dirac equation on asymptotically flat and warped
  products spaces

abstract:
  We prove local smoothing estimates for the Dirac equation on some non-flat
manifolds; in particular, we will consider asymptotically flat and warped
products metrics. The strategy of the proofs relies on the multiplier method.


title: Nonlocal Nambu-Jona-Lasinio model and chiral chemical potential

abstract:
  We derive the critical temperature in a nonlocal Nambu-Jona-Lasinio model
with the presence of a chiral chemical potential. The model we consider uses a
form factor derived from recent studies of the gluon propagator in Yang-Mills
theory and has the property to fit in excellent way the form factor arising
from the instanton liquid picture for the vacuum of the theory.
Nambu-Jona-Lasinio model is derived form quantum chromodynamics providing all
the constants of the theory without any need for fits. We show that the
critical temperature in this case always exists and increases as the square of
the chiral chemical potential. The expression we obtain for the critical
temperature depends on the mass gap that naturally arises from Yang-Mills
theory at low-energy as also confirmed by lattice computations.


title:
Semiclassical Theory of Superresolution for Two Incoherent Optical Point
  Sources

abstract:
  Using a semiclassical model of photodetection with Poissonian noise and
insights from quantum metrology, we prove that linear optics and photon
counting can optimally estimate the separation between two incoherent point
sources without regard to Rayleigh's criterion. The model is applicable to weak
thermal or fluorescent sources as well as lasers.


title: Dividend maximization in a hidden Markov switching model

abstract:
  In this paper we study the valuation problem of an insurance company by
maximizing the expected discounted future dividend payments in a model with
partial information that allows for a changing economic environment. The
surplus process is modeled as a Brownian motion with drift. This drift depends
on an underlying Markov chain the current state of which is assumed to be
unobservable. The different states of the Markov chain thereby represent
different phases of the economy. We apply results from filtering theory to
overcome uncertainty and then we give an analytic characterization of the
optimal value function. Finally, we present a numerical study covering various
scenarios to get a clear picture of how dividends should be paid out.


title: In situ TEM study of twin boundary migration in sub-micron Be fibers

abstract:
  Deformation twinning in hexagonal crystals is often considered as a way to
palliate the lack of independent slip systems. This mechanism might be either
exacerbated or shut down in small-scale crystals whose mechanical behavior can
significantly deviate from bulk materials. Here, we show that sub-micron
beryllium fibers initially free of dislocation and tensile tested in-situ in a
transmission electron microscope (TEM) deform by a $\{ 10\bar{1}2 \}$ $\langle
10\bar{1}1 \rangle$ twin thickening. The propagation speed of the twin boundary
seems to be entirely controlled by the nucleation of twinning dislocations
directly from the surface. The shear produced is in agreement with the repeated
lateral motion of twinning dislocations. We demonstrate that the activation
volume ($V$) associated with the twin boundary propagation can be retrieved
from the measure of the twin boundary speed as the stress decreases as in a
classical relaxation mechanical test. The value of $V \approx 8.3 \pm 3.3
\times 10^{-29}m^3$ is comparable to the value expected from surface
nucleation.


title: Bifurcations of families of 1D-tori in 4D symplectic maps

abstract:
  The regular structures of a generic 4D symplectic map with a mixed phase
space are organized by one-parameter families of elliptic 1D-tori. Such
families show prominent bends, gaps, and new branches. We explain these
features in terms of bifurcations of the families when crossing a resonance.
For these bifurcations no external parameter has to be varied. Instead, the
longitudinal frequency, which varies along the family, plays the role of the
bifurcation parameter. As an example we study two coupled standard maps by
visualizing the elliptic and hyperbolic 1D-tori in a 3D phase-space slice,
local 2D projections, and frequency space. The observed bifurcations are
consistent with analytical predictions previously obtained for
quasi-periodically forced oscillators. Moreover, the new families emerging from
such a bifurcation form the skeleton of the corresponding resonance channel.


title:
A survey of luminous high-redshift quasars with SDSS and WISE. I. target
  selection and optical spectroscopy

abstract:
  High-redshift quasars are important tracers of structure and evolution in the
early universe. However, they are very rare and difficult to find when using
color selection because of contamination from late-type dwarfs. High-redshift
quasar surveys based on only optical colors suffer from incompleteness and low
identification efficiency, especially at $z\gtrsim4.5$. We have developed a new
method to select $4.7\lesssim z \lesssim 5.4$ quasars with both high efficiency
and completeness by combining optical and mid-IR Wide-field Infrared Survey
Explorer (WISE) photometric data, and are conducting a luminous $z\sim5$ quasar
survey in the whole Sloan Digital Sky Survey (SDSS) footprint. We have
spectroscopically observed 99 out of 110 candidates with $z$-band magnitudes
brighter than 19.5 and 64 (64.6\%) of them are quasars with redshifts of
$4.4\lesssim z \lesssim 5.5$ and absolute magnitudes of $-29\lesssim M_{1450}
\lesssim -26.4$. In addition, we also observed 14 fainter candidates selected
with the same criteria and identified 8 (57.1\%) of them as quasars with
$4.7<z<5.4$ . Among 72 newly identified quasars, 12 of them are at $5.2 < z <
5.7$, which leads to an increase of $\sim$36\% of the number of known quasars
at this redshift range. More importantly, our identifications doubled the
number of quasars with $M_{1450}<-27.5$ at $z>4.5$, which will set strong
constraints on the bright end of the quasar luminosity function. We also expand
our method to select quasars at $z\gtrsim5.7$. In this paper we report the
discovery of four new luminous $z\gtrsim5.7$ quasars based on SDSS-WISE
selection.


title: Bayesian Dividend Optimization and Finite Time Ruin Probabilities

abstract:
  We consider the valuation problem of an (insurance) company under partial
information. Therefore we use the concept of maximizing discounted future
dividend payments. The firm value process is described by a diffusion model
with constant and observable volatility and constant but unknown drift
parameter. For transforming the problem to a problem with complete information,
we derive a suitable filter. The optimal value function is characterized as the
unique viscosity solution of the associated Hamilton-Jacobi-Bellman equation.
We state a numerical procedure for approximating both the optimal dividend
strategy and the corresponding value function. Furthermore, threshold
strategies are discussed in some detail. Finally, we calculate the probability
of ruin in the uncontrolled and controlled situation.


title: The weight distribution of the self-dual $[128,64]$ polarity design code

abstract:
  The weight distribution of the binary self-dual $[128,64]$ code being the
extended code $C^{*}$ of the code $C$ spanned by the incidence vectors of the
blocks of the polarity design in $PG(6,2)$ [11] is computed. It is shown also
that $R(3,7)$ and $C^{*}$ have no self-dual $[128,64,d]$ neighbor with $d \in
\{ 20, 24 \}$.


title:
Optimal Control of an Energy Storage Facility Under a Changing Economic
  Environment and Partial Information

abstract:
  In this paper we consider an energy storage optimization problem in finite
time in a model with partial information that allows for a changing economic
environment. The state process consists of the storage level controlled by the
storage manager and the energy price process, which is a diffusion process the
drift of which is assumed to be unobservable. We apply filtering theory to find
an alternative state process which is adapted to our observation filtration.
For this alternative state process we derive the associated
Hamilton-Jacobi-Bellman equation and solve the optimization problem
numerically. This results in a candidate for the optimal policy for which it is
a-priori not clear whether the controlled state process exists. Hence, we prove
an existence and uniqueness result for a class of time-inhomogeneous stochastic
differential equations with discontinuous drift and singular diffusion
coefficient. Finally, we apply our result to prove admissibility of the
candidate optimal control.


title:
Quantum-classical hybrids in a simplified model of QED and geometric
  phase induced by charged particle trajectory

abstract:
  We derive a model of quantum-classical hybrids for a simplified model of
quantum electrodynamics in the framework of the stochastic variational method.
In this model, charged particle trajectories are affected by the interaction
with quantized electromagnetic fields, and this quantum-classical interaction
induces a displacement current. We further investigate a geometric phase in the
wave functional of the gauge field configuration, which is induced by adiabatic
motions of the charged particles. This phase contains the quantum-classical
backreaction effect and usual Berry's phase is reproduced in the vanishing
limit of the fluctuation of the charged particle trajectories.


title: A class of linear viscoelastic models based on Bessel functions

abstract:
  In this paper we investigate a general class of linear viscoelastic models
whose creep and relaxation memory functions are expressed in Laplace domain by
suitable ratios of modified Bessel functions of contiguous order. In time
domain these functions are shown to be expressed by Dirichlet series (that is
infinite Prony series). It follows that the corresponding creep compliance and
relaxation modulus turn out to be characterized by infinite discrete spectra of
retardation and relaxation time respectively. As a matter of fact, we get a
class of viscoelastic models depending on a real parameter $\nu > -1$. Such
models exhibit rheological properties akin to those of a fractional Maxwell
model (of order $1/2$) for short times and of a standard Maxwell model for long
times.


title:
Wind Dynamics and Circumstellar Extinction Variations in the T Tauri
  Star RY Tau

abstract:
  The wind interaction with the dusty environment of the classical T Tauri star
RY Tau has been investigated. During two seasons of 2013-2015 we carried out a
spectroscopic and photometric (BVR) monitoring of the star. A correlation
between the stellar brightness and the radial velocity of the wind determined
from the H-alpha and Na D line profiles has been found for the first time. The
irregular stellar brightness variations are shown to be caused by extinction in
a dusty disk wind at a distance of about 0.2 AU from the star. We suppose, that
variations of the circumstellar extinction results from cyclic rearrangements
of the stellar magnetosphere and coronal mass ejections, which affect the dusty
disk wind near the inner boundary of the circumstellar disk.


title: Gravitational Wave Detection in the Introductory Lab

abstract:
  Great physics breakthroughs are rarely included in the introductory physics
or astronomy course. General relativity and binary black hole coalescence are
no different, and can be included in the introductory course only in a very
limited sense. However, we can design activities that directly involve the
detection of GW150914, the designation of the Gravitation Wave signal detected
on September 14, 2015, thereby engage the students in this exciting discovery
directly. The activities naturally do not include the construction of a
detector or the detection of gravitational waves. Instead, we design it to
include analysis of the data from GW150914, which includes some interesting
analysis activities for students of the introductory course. The same
activities can be assigned either as a laboratory exercise or as a
computational project for the same population of students. The analysis tools
used here are simple and available to the intended student population. It does
not include the sophisticated analysis tools, which was used by LIGO to
carefully analyze the detected signal. However, these simple tools are
sufficient to allow the student to get important results.


title: Rapid Asynchronous Plurality Consensus

abstract:
  We consider distributed plurality consensus in a complete graph of size $n$
with $k$ initial opinions. We design an efficient and simple protocol in the
asynchronous communication model that ensures that all nodes eventually agree
on the initially most frequent opinion. In this model, each node is equipped
with a random Poisson clock with parameter $\lambda=1$. Whenever a node's clock
ticks, it samples some neighbors, uniformly at random and with replacement, and
adjusts its opinion according to the sample.
  A prominent example is the so-called two-choices algorithm in the synchronous
model, where in each round, every node chooses two neighbors uniformly at
random, and if the two sampled opinions coincide, then that opinion is adopted.
This protocol is very efficient and well-studied when $k=2$. If
$k=O(n^\varepsilon)$ for some small $\varepsilon$, we show that it converges to
the initial plurality opinion within $O(k \cdot \log{n})$ rounds, w.h.p., as
long as the initial difference between the largest and second largest opinion
is $\Omega(\sqrt{n \log n})$. On the other side, we show that there are cases
in which $\Omega(k)$ rounds are needed, w.h.p.
  One can beat this lower bound in the synchronous model by combining the
two-choices protocol with randomized broadcasting. Our main contribution is a
non-trivial adaptation of this approach to the asynchronous model. If the
support of the most frequent opinion is at least $(1+\varepsilon)$ times that
of the second-most frequent one and $k=O(\exp(\log{n}/\log \log{n}))$, then our
protocol achieves the best possible run time of $O(\log n)$, w.h.p. We relax
full synchronicity by allowing $o(n)$ nodes to be poorly synchronized, and the
well synchronized nodes are only required to be within a certain time
difference from one another. We enforce this synchronicity by introducing a
novel gadget into the protocol.


title:
On the nonexistence of $k$-reptile simplices in $\mathbb R^3$ and
  $\mathbb R^4$

abstract:
  A $d$-dimensional simplex $S$ is called a $k$-reptile (or a $k$-reptile
simplex) if it can be tiled by $k$ simplices with disjoint interiors that are
all mutually congruent and similar to $S$. For $d=2$, triangular $k$-reptiles
exist for all $k$ of the form $a^2, 3a^2$ or $a^2 + b^2$ and they have been
completely characterized by Snover, Waiveris, and Williams. On the other hand,
the only $k$-reptile simplices that are known for $d \ge 3$, have $k = m^d$,
where $m$ is a positive integer. We substantially simplify the proof by
Matou\v{s}ek and the second author that for $d=3$, $k$-reptile tetrahedra can
exist only for $k=m^3$. We then prove a weaker analogue of this result for
$d=4$ by showing that four-dimensional $k$-reptile simplices can exist only for
$k=m^2$.


title:
From Simplicial Homotopy to Crossed Module Homotopy in Modified
  Categories of Interest

abstract:
  We address the (pointed) homotopy of crossed module morphisms in modified
categories of interest; which generalizes the groups and various algebraic
structures. We prove that, the homotopy relation gives rise to an equivalence
relation; furthermore a groupoid structure, without any restriction on neither
domain nor co-domain of the crossed module morphism. Additionally, we consider
the particular cases such as associative algebras, Leibniz algebras, Lie
algebras and dialgebras of crossed modules of this generalized homotopy
definition. Then as the main part of the paper, we prove that the functor from
simplicial objects to crossed modules in modified categories of interest
preserves the homotopy and also the homotopy equivalence.


title:
Exploring the Anomalous Top-Higgs FCNC Couplings at the electron proton
  colliders

abstract:
  We perform an updated analysis on the searches for the anomalous FCNC Yukawa
interactions between the top quark, the Higgs boson, and either an up or charm
quark ($\rm tqh,\ q=u,\ c$). We probe the observability of the FCNC top-Higgs
couplings through the processes $\rm e^- p\rightarrow \nu_e \bar{t} \rightarrow
\nu_e h \bar{q}$ (signal.I) and $\rm \ e^- p \to \nu_e h b$ (singal.II) at the
proposed electron proton (ep) colliders, where the Higgs boson decays to a $\rm
b\bar{b}$ pair. We find that at the high luminosity (1 $\rm ab^{-1}$) ep
colliders where the electrons have a polarisation of $\rm 80\%$ and electron
energy is typical 60 GeV, the 2$\sigma$ upper limit on $\rm Br(t\to uh)$ are
$0.15\times 10^{-2}$($2.9\times 10^{-4}$) at the 7TeV@LHeC(50TeV@FCC-eh) for
signal.I and $0.15\times 10^{-2}$($2.2\times 10^{-4}$) for signal.II. We also
give an estimate on how the sensitivity (take signal.I as examples) would
change when we reduce the electron beam energy from 60 GeV to 50 GeV or even 40
GeV due to the cost reason. The conclusion is that the discovery potential
reduce $8.7\%$($29.4\%$) if the electron beam change from 60GeV to 50(40) GeV
at the 7TeV LHeC, and $16.8\%$($19.8\%$) at the 50 TeV FCC-eh.


title: Phylogenetic mixtures and linear invariants for equal input models

abstract:
  The reconstruction of phylogenetic trees from molecular sequence data relies
on modelling site substitutions by a Markov process, or a mixture of such
processes. In general, allowing mixed processes can result in different tree
topologies becoming indistinguishable from the data, even for infinitely long
sequences. However, when the underlying Markov process supports linear
phylogenetic invariants, then provided these are sufficiently informative, the
identifiability of the tree topology can be restored. In this paper, we
investigate a class of processes that support linear invariants once the
stationary distribution is fixed, the `equal input model'. This model
generalizes the `Felsenstein 1981' model (and thereby the Jukes--Cantor model)
from four states to an arbitrary number of states (finite or infinite), and it
can also be described by a `random cluster' process. We describe the structure
and dimension of the vector spaces of phylogenetic mixtures and of linear
invariants for any fixed phylogenetic tree (and for all trees -- the so called
`model invariants'), on any number $n$ of leaves. We also provide a precise
description of the space of mixtures and linear invariants for the special case
of $n=4$ leaves. By combining techniques from discrete random processes and
(multi-) linear algebra, our results build on a classic result that was first
established by James Lake in 1987.


title: Black Hole Mass Estimation: How good is the virial estimate?

abstract:
  Black hole mass is a key factor in determining how a black hole interacts
with its environment. However, the determination of black hole masses at high
redshifts depends on secondary mass estimators, which are based on empirical
relationships and broad approximations. A dynamical disk wind broad line region
(BLR) model of active galactic nuclei (AGN) is built in order to test the
impact on the black hole mass calculation due to different BLR geometries and
the inclination of the AGN. Monte Carlo simulations of two disk wind models are
constructed to recover the virial scale factor, $f$, at various inclination
angles. The resulting $f$ values strongly correlate with inclination angle,
with large $f$ values associated with small inclination angles (close to
face-on) and small $f$ values with large inclination angles (close to edge-on).
  The $f$ factors are consistent with previously determined $f$ values, found
from empirical relationships. Setting $f$ as a constant may introduce a bias
into virial black hole mass estimates for a large sample of AGN. However, the
extent of the bias depends on the line width characterisation (e.g. full width
at half maximum (FWHM) or line dispersion). Masses estimated using
$f_{\text{FWHM}}$ tend to biased towards larger masses, but this can be
corrected by calibrating for the width or shape of the emission line.


title:
A formula for the partition function of the beta-gamma system on the
  cone pure spinors

abstract:
  In this note, we propose a closed formula for the partition function $Z(t,q)$
of the $\beta\gamma$ system on the cone of pure spinors. We give the answer in
terms of theta functions, $q$-Pochhammer symbols and Eisenstein series.


title: Einstein and Gravitational Waves 1936-1938

abstract:
  Around 1936, Einstein wrote to his close friend Max Born telling him that,
together with Nathan Rosen, he had arrived at the interesting result that
gravitational waves did not exist, though they had been assumed a certainty to
the first approximation. He finally had found a mistake in his 1936 paper with
Rosen and believed that gravitational waves do exist. However, in 1938,
Einstein again obtained the result that there could be no gravitational waves!


title: Intervals of Antichains and Their Decompositions

abstract:
  An antichain of subsets is a set of subsets such that no subset in the
antichain is a proper subset of any other subset in the antichain. The Dedekind
number counts the total number of antichains of subsets of an n-element set.
This paper investigates the interval structure of the lattice of antichains.
Several partitioning theorems and counting formulas for the size of intervals
are derived.


title: Maximin Action Identification: A New Bandit Framework for Games

abstract:
  We study an original problem of pure exploration in a strategic bandit model
motivated by Monte Carlo Tree Search. It consists in identifying the best
action in a game, when the player may sample random outcomes of sequentially
chosen pairs of actions. We propose two strategies for the fixed-confidence
setting: Maximin-LUCB, based on lower-and upper-confidence bounds; and
Maximin-Racing, which operates by successively eliminating the sub-optimal
actions. We discuss the sample complexity of both methods and compare their
performance empirically. We sketch a lower bound analysis, and possible
connections to an optimal algorithm.


title: Holomorphic affine connections on non-K\"ahler manifolds

abstract:
  Our aim here is to investigate the holomorphic geometric structures on
compact complex manifolds which may not be K\"ahler. We prove that holomorphic
geometric structures of affine type on compact Calabi-Yau manifolds with
polystable tangent bundle (with respect to some Gauduchon metric on it) are
locally homogeneous. In particular, if the geometric structure is rigid in
Gromov's sense, then the fundamental group of the manifold must be infinite. We
also prove that compact complex manifolds of algebraic dimension one bearing a
holomorphic Riemannian metric must have infinite fundamental group.


title: Percolation assisted excitation transport in discrete-time quantum walks

abstract:
  Coherent transport of excitations along chains of coupled quantum systems
represents an interesting problem with a number of applications ranging from
quantum optics to solar cell technology. A convenient tool for studying such
processes are quantum walks. They allow to determine in a quantitative way all
the process features. We study the survival probability and the transport
efficiency on a simple, highly symmetric graph represented by a ring. The
propagation of excitation is modeled by a discrete-time (coined) quantum walk.
For a two-state quantum walk, where the excitation (walker) has to leave its
actual position to the neighboring sites, the survival probability decays
exponentially and the transport efficiency is unity. The decay rate of the
survival probability can be estimated using the leading eigenvalue of the
evolution operator. However, if the excitation is allowed to stay at its
present position, i.e. the propagation is modeled by a lazy quantum walk, then
part of the wave-packet can be trapped in the vicinity of the origin and never
reaches the sink. In such a case, the survival probability does not vanish and
the excitation transport is not efficient. The dependency of the transport
efficiency on the initial state is determined. Nevertheless, we show that for
some lazy quantum walks dynamical percolations of the ring eliminate the
trapping effect and efficient excitation transport can be achieved.


title:
Optimal curing policy for epidemic spreading over a community network
  with heterogeneous population

abstract:
  The design of an efficient curing policy, able to stem an epidemic process at
an affordable cost, has to account for the structure of the population contact
network supporting the contagious process. Thus, we tackle the problem of
allocating recovery resources among the population, at the lowest cost possible
to prevent the epidemic from persisting indefinitely in the network.
Specifically, we analyze a susceptible-infected-susceptible epidemic process
spreading over a weighted graph, by means of a first-order mean-field
approximation. First, we describe the influence of the contact network on the
dynamics of the epidemics among a heterogeneous population, that is possibly
divided into communities. For the case of a community network, our
investigation relies on the graph-theoretical notion of equitable partition; we
show that the epidemic threshold, a key measure of the network robustness
against epidemic spreading, can be determined using a lower-dimensional
dynamical system. Exploiting the computation of the epidemic threshold, we
determine a cost-optimal curing policy by solving a convex minimization
problem, which possesses a reduced dimension in the case of a community
network. Lastly, we consider a two-level optimal curing problem, for which an
algorithm is designed with a polynomial time complexity in the network size.


title:
Morphology and chemical composition of cobalt germanide islands on
  Ge(001): in-situ nanoscale insights into contact formation for Ge-based
  device technology

abstract:
  The reactive growth of cobalt germanide on Ge(001) was investigated by means
of in-situ x-ray absorption spectroscopy photoemission electron microscopy
(XAS-PEEM), micro-illumination low-energy electron diffraction ($\mu$-LEED),
and ex-situ atomic force microscopy (AFM). At a Co deposition temperature of
670{\deg}C, a rich morphology with different island shapes and dimensions is
observed, and a correlation between island morphology and stoichiometry is
found. Combining XAS-PEEM and $\mu$-LEED, we were able to identify a large part
of the islands to consist of CoGe$_2$, with many of them having an unusual
epitaxial relationship: CoGe$_2$[$\bar110$](111) $\parallel$
Ge[$\bar110$](001). Side facets with (112) and (113) orientation have been
found for such islands. However, two additional phases were observed, most
likely Co$_5$Ge$_7$ and CoGe. The occurrence of these intermediate phases is
promoted by defects, as revealed by comparing growth on Ge(001) single crystals
and on Ge(001)/Si(001) epilayer substrates.


title:
Near room-temperature memory devices based on hybrid spin-crossover SiO2
  nanoparticles coupled to single-layer graphene nanoelectrodes

abstract:
  In this paper, we report on the charge transport properties of hybrid
nanoparticles (NPs) based on the polymeric 1D compound [Fe(Htrz)2(trz)](BF4),
which is one of the most promising SCO systems for designing electronic
devices. In particular, we used for the first time hybrid SCO NPs covered with
a silica shell and placed in between single-layer graphene electrodes. We
evidence a reproducible thermal hysteresis loop in the conductance above
room-temperature, meaning that no degradation of the current levels has been
detected; we thus conclude that the robustness of the spin-transition is
significantly improved as compared with previous results and with other reports
where even larger assemblies and SCO objects were involved. This bistability
combined with the versatility of graphene represents a promising scenario for a
variety of technological applications but also for future sophisticated
fundamental studies.


title:
HD 41641: A classical $\delta$ Sct-type pulsator with chemical
  signatures of an Ap star

abstract:
  Among the known groups of pulsating stars, $\delta$ Sct stars are one of the
least understood. Theoretical models do not predict the oscillation frequencies
that observations reveal. Complete asteroseismic studies are necessary to
improve these models and better understand the internal structure of these
targets. We study the $\delta$ Sct star HD 41641 with the ultimate goal of
understanding its oscillation pattern. The target was simultaneously observed
by the CoRoT space telescope and the HARPS high-resolution spectrograph. The
photometric data set was analyzed with the software package PERIOD04, while
FAMIAS was used to analyze the line profile variations. The method of spectrum
synthesis was used for spectroscopically determining the fundamental
atmospheric parameters and individual chemical abundances. A total of 90
different frequencies was identified and analyzed. An unambiguous
identification of the azimuthal order of the surface geometry could only be
provided for the dominant p-mode, which was found to be a nonradial prograde
mode with m = +1. Using $T_\mathrm{eff}$ and $\log g$, we estimated the mass,
radius, and evolutionary stage of HD 41641. We find HD 41641 to be a moderately
rotating, slightly evolved $\delta$ Sct star with subsolar overall atmospheric
metal content and unexpected chemical peculiarities. HD 41641 is a pure
$\delta$ Sct pulsator with p-mode frequencies in the range from 10 d$^{-1}$ to
20 d$^{-1}$. This pulsating star presents chemical signatures of an Ap star and
rotational modulation due to surface inhomogeneities, which we consider
indirect evidence of the presence of a magnetic field.


title: The orbit of Beta Pic b as a transiting planet

abstract:
  In 1981, Beta Pictoris showed strong and rapid photometric variations
possibly due to a transiting giant planet. Later, a planetary mass companion to
the star, Beta Pic b, was identified using imagery. Observations at different
epochs (2003 and 2009-2015) detected the planet at a projected distance of 6 to
9 AU from the star and showed that the planet is on an edge-on orbit. The
observed motion is consistent with an inferior conjunction in 1981, and Beta
Pic b can be the transiting planet proposed to explain the photometric event
observed at that time. Assuming that the 1981 event is related to the transit
or the inferior conjunction of Beta Pic b on an edge-on orbit, we search for
the planetary orbit in agreement with all the measurements of the planet
position published so far. We find two different orbits that are compatible
with all these constraints: (i) an orbit with a period of 17.97$\pm$0.08 years
along with an eccentricity of around 0.12 and (ii) an orbit with a period of
36.38$\pm$0.13 years and a larger eccentricity of about 0.32. In the near
future, new imaging observations should allow us to discriminate between these
two different orbits. We also estimate the possible dates for the next
transits, which could take place as early as 2017 or 2018, even for a
long-period orbit.


title:
Numerical method for solving electromagnetic wave scattering by one and
  many small perfectly conducting bodies

abstract:
  In this paper, we investigate the problem of electromagnetic (EM) wave
scattering by one and many small perfectly conducting bodies and present a
numerical method for solving it. For the case of one body, the problem is
solved for a body of arbitrary shape, using the corresponding boundary integral
equation. For the case of many bodies, the problem is solved asymptotically
under the physical assumptions $a\ll d \ll \lambda$, where $a$ is the
characteristic size of the bodies, $d$ is the minimal distance between
neighboring bodies, $\lambda=2\pi/k$ is the wave length and $k$ is the wave
number. Numerical results for the cases of one and many small bodies are
presented. Error analysis for the numerical method are also provided.


title: On the initial value formulation of classical electrodynamics

abstract:
  We describe a seemingly unnoticed feature of the text-book Maxwell-Lorentz
system of classical electrodynamics which challenges its formulation in terms
of an initial value problem. For point-charges, even after appropriate
renormalization, we demonstrate that most of the generic initial data evolves
to develop singularities in the electromagnetic fields along the light cones of
the initial charge positions. We provide explicit formulas for the
corresponding fields, demonstrate how this phenomenon renders the initial value
problem ill-posed, and show how such bad initial data can be ruled out by extra
conditions in addition to the Maxwell constraints. These extra conditions,
however, require knowledge of the history of the solution and, as we discuss,
effectively turn the Maxwell-Lorentz system into a system of delay equations
much like the Fokker-Schwarzschild-Tetrode equations. For extended charges such
singular light fronts persist in a smoothened form and, as we argue, yield
physically doubtful solutions. Our results also apply to some extent to
expectation values of field operators in quantum field theory.


title: Local and non-local thermopowers in three-terminal nanostructures

abstract:
  The thermoelectric effects in three-terminal structures with a quantum dot
are considered. We propose the experimentally consistent protocol for
determination of the transport coefficients in terms of the local and non-local
conductances and thermopowers that can be measured in two steps, applying the
`four probe technique'. This proposal is compared with other approaches
discussed so far in the literature. As an example we study in detail the
thermopower induced by the superconducting electrode in a subgap regime which
might be useful for analysis of novel hybrid devices.


title:
Conformal embeddings of affine vertex algebras in minimal $W$-algebras
  I: structural results

abstract:
  We find all values of $k\in \mathbb C$, for which the embedding of the
maximal affine vertex algebra in a simple minimal W-algebra $W_k(\mathfrak
g,\theta)$ is conformal, where $\mathfrak g$ is a basic simple Lie superalgebra
and $-\theta$ its minimal root. In particular, it turns out that if
$W_k(\mathfrak g,\theta)$ does not collapse to its affine part, then the
possible values of these $k$ are either $-\frac{2}{3} h^\vee$ or
$-\frac{h^\vee-1}{2}$, where $h^\vee$ is the dual Coxeter number of $\mathfrak
g$ for the normalization $(\theta,\theta)=2$. As an application of our results,
we present a realization of simple affine vertex algebra $V_{-\tfrac{n+1}{2} }
(sl(n+1))$ inside of the tensor product of the vertex algebra
$W_{\tfrac{n-1}{2}} (sl(2| n), \theta)$ (also called the Bershadsky-Knizhnik
algebra) with a lattice vertex algebra.


title: An efficient threshold dynamics method for wetting on rough surfaces

abstract:
  The threshold dynamics method developed by Merriman, Bence and Osher (MBO) is
an efficient method for simulating the motion by mean curvature flow when the
interface is away from the solid boundary. Direct generalization of MBO-type
methods to the wetting problem with interfaces intersecting the solid boundary
is not easy because solving the heat equation in a general domain with a
wetting boundary condition is not as efficient as it is with the original MBO
method. The dynamics of the contact point also follows a different law compared
with the dynamics of the interface away from the boundary. In this paper, we
develop an efficient volume preserving threshold dynamics method for simulating
wetting on rough surfaces. This method is based on minimization of the weighted
surface area functional over an extended domain that includes the solid phase.
The method is simple, stable with $O(N \log N)$ complexity per time step and is
not sensitive to the inhomogeneity or roughness of the solid boundary.


title: Character degrees of some $p$-groups

abstract:
  We restrict the possibilities for the character degrees of $p$-groups $G$
satisfying $|G:G'| = p^2$. E.g. if $G$ is of maximal class and has an
irreducible character of degree $> p$, then it has such a character of degree
at most $p^{\frac{p+1}{2}}$.


title: Towards Diffraction in Herwig

abstract:
  We propose changes to the colour reconnection model in the Monte Carlo event
generator Herwig in order to remove the quasi diffractive events from the soft
multiple parton interactions. We then implement explicitly soft diffraction and
show some preliminary results.


title:
A Fast Algorithm for Solving Scalar Wave Scattering Problem by Billions
  of Particles

abstract:
  Scalar wave scattering by many small particles of arbitrary shapes with
impedance boundary condition is studied. The problem is solved asymptotically
and numerically under the assumptions a << d << lambda, where k = 2pi/lambda is
the wave number, lambda is the wave length, a is the characteristic size of the
particles, and d is the smallest distance between neighboring particles. A fast
algorithm for solving this wave scattering problem by billions of particles is
presented. The algorithm comprises the derivation of the (ORI) linear system
and makes use of Conjugate Orthogonal Conjugate Gradient method and Fast
Fourier Transform. Numerical solutions of the scalar wave scattering problem
with 1, 4, 7, and 10 billions of small impedance particles are achieved for the
first time. In these numerical examples, the problem of creating a material
with negative refraction coefficient is also described and a recipe for
creating materials with a desired refraction coefficient is tested.


title: Photons, Photon Jets and Dark Photons at 750 GeV and Beyond

abstract:
  In new physics searches involving photons at the LHC, one challenge is to
distinguish scenarios with isolated photons from models leading to "photon
jets". For instance, in the context of the 750 GeV diphoton excess, it was
pointed out that a true diphoton resonance $S \to \gamma\gamma$ can be mimicked
by a process of the form $p p \to S \to a a \to 4\gamma$, where $S$ is a new
scalar with a mass of 750 GeV and $a$ is a light pseudoscalar decaying to two
collinear photons. Photon jets can be distinguished from isolated photons by
exploiting the fact that a large fraction of photons convert to an $e^+e^-$
pair inside the inner detector. In this note, we quantify this discrimination
power, and we study how the sensitivity of future searches differs for photon
jets compared to isolated photons. We also investigate how our results depend
on the lifetime of the particle(s) decaying to the photon jet. Finally, we
discuss the extension to $S\to A^\prime A^\prime\to e^+e^-e^+e^-$, where there
are no photons at all but the dark photon $A^\prime$ decays to $e^+e^-$ pairs.
Our results will be useful in future studies of the putative 750 GeV signal,
but also more generally in any new physics search involving hard photons.


title: DroidNative: Semantic-Based Detection of Android Native Code Malware

abstract:
  According to the Symantec and F-Secure threat reports, mobile malware
development in 2013 and 2014 has continued to focus almost exclusively ~99% on
the Android platform. Malware writers are applying stealthy mutations
(obfuscations) to create malware variants, thwarting detection by signature
based detectors. In addition, the plethora of more sophisticated detectors
making use of static analysis techniques to detect such variants operate only
at the bytecode level, meaning that malware embedded in native code goes
undetected. A recent study shows that 86% of the most popular Android
applications contain native code, making this a plausible threat. This paper
proposes DroidNative, an Android malware detector that uses specific control
flow patterns to reduce the effect of obfuscations, provides automation and
platform independence, and as far as we know is the first system that operates
at the Android native code level, allowing it to detect malware embedded in
both native code and bytecode. When tested with traditional malware variants it
achieves a detection rate (DR) of 99.48%, compared to academic and commercial
tools' DRs that range from 8.33% -- 93.22%. When tested with a dataset of 2240
samples DroidNative achieves a DR of 99.16%, a false positive rate of 0.4% and
an average detection time of 26.87 sec/sample.


title: Exceptional solutions to the Painlev\'e VI equation

abstract:
  We find all solutions of the Painlev\'e VI equations with the property that
they have no zeros, no poles, no 1-points and no fixed points.


title: A Perron-type theorem for fractional linear differential systems

abstract:
  We give a necessary and sufficient condition for a system of linear
inhomogeneous fractional differential equations to have at least one bounded
solution. We also obtain an explicit description for the set of all bounded (or
decay) solutions for these systems.


title:
Bound state operators and wedge-locality in integrable quantum field
  theories

abstract:
  We consider scalar two-dimensional quantum field theories with the
factorizing S-matrix which has poles in the physical strip. In our previous
work, we introduced the bound state operators and constructed candidate
operators for observables in wedges.
  Under some additional assumptions on the S-matrix, we show that, in order to
obtain their strong commutativity, it is enough to prove the essential
self-adjointness of the sum of the left and right bound state operators. This
essential self-adjointness is shown up to the two-particle component.


title: Method for generating two coupled Gaussian stochastic processes

abstract:
  Most processes in nature are coupled; however, extensive null models for
generating such processes still lacks. We present a new method to generate two
coupled Gaussian stochastic processes with arbitrary correlation functions.
This method is developed by modifying the Fourier filtering method. The
robustness of this method is proved by generating two coupled fractional
Brownian motions and extending its range of application to Gaussian random
fields.

categories: math.PR cond-mat.stat-mech physics.comp-ph physics.data-an


title: A New Characterisation of Total Graphs

abstract:
  Graphs constructed to translate some graph problem into another graph problem
are usually called auxiliary graphs. Specifically total graphs of simple graphs
are used to translate the total colouring problem of the original graph into a
vertex colouring problem of the transformed graph. In this paper, we obtain a
new characterisation of total graphs of simple graphs. We also design
algorithms to compute the inverse total graphs when the input graph is a total
graph. These results improve over the work of Behzad, by using novel
observations on the properties of the local structure in the neighbourhood of
each vertex. The earlier algorithm was based on bfs and distances. Our theorems
result in partitioning the vertex set of the total graph into the original
graph and the line graph efficiently. We obtain constructive results for
special classes, most notably for total graph of complete graphs.


title:
Traversable holographic dark energy wormholes constrained by
  astronomical observations

abstract:
  In this letter, we investigate the traversable wormholes in the holographic
dark energy (HDE) model constrained by the modern astronomical observations.
First of all, we constrain the HDE model by adopting different data-sets,
explore the cosmological background evolution of the HDE model, and find that
the HDE model will be fitting better than the Ricci dark energy (RDE) model for
the same SNe Ia data-sets by using the the so-called Akaike Information
Criterions (AIC) and Bayesian Information Criterions (BIC) . Furthermore, we
discover that if taking the SNe Ia data-sets, the wormholes will appear (open)
when the redshift $z<0.027$. Subsequently, several specific traversable
wormhole solutions are obtained, including the constant redshift function,
traceless stress energy tensor, a special choice for the shape function as well
as the case of isotropic pressure. Except for the first case, it is very
necessary to theoretically construct the traversable wormholes by matching the
exterior geometries to the interior geometries. Naturally, one can easily find
that the dimensions of the wormholes for the left cases are substantially
finite.


title:
Approximation of the least Rayleigh quotient for degree $p$ homogeneous
  functionals

abstract:
  We present two novel methods for approximating minimizers of the abstract
Rayleigh quotient $\Phi(u)/ \|u\|^p$. Here $\Phi$ is a strictly convex
functional on a Banach space with norm $\|\cdot\|$, and $\Phi$ is assumed to be
positively homogeneous of degree $p\in (1,\infty)$. Minimizers are shown to
satisfy $\partial \Phi(u)- \lambda\mathcal{J}_p(u)\ni 0$ for a certain
$\lambda\in \mathbb{R}$, where $\mathcal{J}_p$ is the subdifferential of
$\frac{1}{p}\|\cdot\|^p$. The first approximation scheme is based on inverse
iteration for square matrices and involves sequences that satisfy $$ \partial
\Phi(u_k)- \mathcal{J}_p(u_{k-1})\ni 0 \quad (k\in \mathbb{N}). $$ The second
method is based on the large time behavior of solutions of the doubly nonlinear
evolution $$ \mathcal{J}_p(\dot v(t))+\partial\Phi(v(t))\ni 0 \quad(a.e.\;t>0)
$$ and more generally $p$-curves of maximal slope for $\Phi$. We show that both
schemes have the remarkable property that the Rayleigh quotient is
nonincreasing along solutions and that properly scaled solutions converge to a
minimizer of $\Phi(u)/ \|u\|^p$. These results are new even for Hilbert spaces
and their primary application is in the approximation of optimal constants and
extremal functions for inequalities in Sobolev spaces.


title:
Iran's scientific dominance and the emergence of South-East Asian
  countries as scientific collaborators in the Persian Gulf Region

abstract:
  A longitudinal bibliometric analysis of publications indexed in Thomson
Reuters' Incites and Elsevier's Scopus, and published from Persian Gulf States
and neighbouring Middle East countries, shows clear effects of major political
events during the past 35 years. Predictions made in 2006 by the US diplomat
Richard N. Haass on political changes in the Middle East have come true in the
Gulf States' national scientific research systems, to the extent that Iran has
become in 2015 by far the leading country in the Persian Gulf, and South-East
Asian countries including China, Malaysia and South Korea have become major
scientific collaborators, displacing the USA and other large Western countries.
But collaborations patterns among Persian Gulf States show no apparent
relationship with differences in Islam denominations.


title: Non-signalling boxes and Bohrification

abstract:
  The premise of this note is the following observation: the formalism of
Bohrification is a natural place for the interpretation of general
non-signalling theories. We demonstrate it through an analysis of so-called
box-worlds, a popular framework for the discussion of systems exhibiting
super-quantum correlations. In particular, we show that non-signalling
box-world states are precisely the internal probability valuations on an
internal frame in a Kripke topos naturally associated with a given box world.


title:
Decoherence wave in magnetic systems and creation of N\'eel
  antiferromagnetic state by measurement

abstract:
  The interplay between the singlet ground state of the antiferromagnetic
Heisenberg model and the experimentally measured N\'eel state of
antiferromagnets is studied. To verify the hypothesis [M. I. Katsnelson et al.,
Phys. Rev. B 63, 212404 (2001)] that the latter can be considered to be a
result of local measurements destroying the entanglement of the quantum ground
state, we have performed systematic simulations of the effects of von
Neumannmeasurements for the case of a one-dimensional antiferromagnetic
spin-1/2 system for various types and degrees of magnetic anisotropies. It is
found that in the ground state, a magnetization measurement can create
decoherence waves [M. I. Katsnelson et al. Phys. Rev. A 62, 022118 (2000)] in
the magnetic sublattices, and that a symmetry breaking anisotropy does not lead
to alignment of the spins in a particular direction. However, for an easy-axis
anisotropy of the same order magnitude as the exchange constant, a measurement
on the singlet ground state can create N\'eel-ordering in finite systems of
experimentally accessible size.

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


title:
Quasi-Monte Carlo and Multilevel Monte Carlo Methods for Computing
  Posterior Expectations in Elliptic Inverse Problems

abstract:
  We are interested in computing the expectation of a functional of a PDE
solution under a Bayesian posterior distribution. Using Bayes' rule, we reduce
the problem to estimating the ratio of two related prior expectations. For a
model elliptic problem, we provide a full convergence and complexity analysis
of the ratio estimator in the case where Monte Carlo, quasi-Monte Carlo or
multilevel Monte Carlo methods are used as estimators for the two prior
expectations. We show that the computational complexity of the ratio estimator
to achieve a given accuracy is the same as the corresponding complexity of the
individual estimators for the numerator and the denominator. We {also include
numerical simulations, in the context of the model elliptic problem, which
demonstrate the effectiveness of the approach.


title: Double ramification cycles on the moduli spaces of curves

abstract:
  Curves of genus g which admit a map to CP1 with specified ramification
profile mu over 0 and nu over infinity define a double ramification cycle
DR_g(mu,nu) on the moduli space of curves. The study of the restrictions of
these cycles to the moduli of nonsingular curves is a classical topic. In 2003,
Hain calculated the cycles for curves of compact type. We study here double
ramification cycles on the moduli space of Deligne-Mumford stable curves.
  The cycle DR_g(mu,nu) for stable curves is defined via the virtual
fundamental class of the moduli of stable maps to rubber. Our main result is
the proof of an explicit formula for DR_g(mu,nu) in the tautological ring
conjectured by Pixton in 2014. The formula expresses the double ramification
cycle as a sum over stable graphs (corresponding to strata classes) with
summand equal to a product over markings and edges. The result answers a
question of Eliashberg from 2001 and specializes to Hain's formula in the
compact type case.
  When mu and nu are both empty, the formula for double ramification cycles
expresses the top Chern class lambda_g of the Hodge bundle of the moduli space
of stable genus g curves as a push-forward of tautological classes supported on
the divisor of nonseparating nodes. Applications to Hodge integral calculations
are given.


title:
Energy-Efficient Time Synchronization Based on Asynchronous Source Clock
  Frequency Recovery and Reverse Two-Way Message Exchanges in Wireless Sensor
  Networks

abstract:
  We consider energy-efficient time synchronization in a wireless sensor
network where a head node (i.e., a gateway between wired and wireless networks
and a center of data fusion) is equipped with a powerful processor and supplied
power from outlet, and sensor nodes (i.e., nodes measuring data and connected
only through wireless channels) are limited in processing and battery-powered.
It is this asymmetry that our study focuses on; unlike most existing schemes to
save the power of all network nodes, we concentrate on battery-powered sensor
nodes in minimizing energy consumption for time synchronization. We present a
time synchronization scheme based on asynchronous source clock frequency
recovery and reverse two-way message exchanges combined with measurement data
report messages, where we minimize the number of message transmissions from
sensor nodes, and carry out the performance analysis of the estimation of both
measurement time and clock frequency with lower bounds for the latter.
Simulation results verify that the proposed scheme outperforms the schemes
based on conventional two-way message exchanges with and without clock
frequency recovery in terms of the accuracy of measurement time estimation and
the number of message transmissions and receptions at sensor nodes as an
indirect measure of energy efficiency.


title:
A 3D Sweep Hull Algorithm for computing Convex Hulls and Delaunay
  Triangulation

abstract:
  This paper presents a new O(nlog(n)) algorithm for computing the convex hull
of a set of 3 dimensional points. The algorithm first sorts the point in
(x,y,z) then incrementally adds sorted points to the convex hull using the
constraint that each new point added to the hull can 'see' at least one facet
touching the last point added. The reduces the search time for adding new
points. The algorithm belongs to the family of swept hull algorithms.
  While slower than q-hull for the general case it significantly outperforms
q-hull for the pathological case where all of the points are on the 3D hull (as
is the case for Delaunay triangulation). The algorithm has been named the
'Newton Apple Wrapper algorithm' and has been released under GPL in C++.
keywords: Delaunay triangulation, 3D convex hull.


title: Giant flux jumps through a thin superconducting Nb film

abstract:
  The dynamics of magnetic field penetration into thin-walled superconducting
niobium cylinders is experimentally investigated. It is shown that magnetic
field penetrates through the wall of a cylinder in a series of giant jumps with
amplitude 10 - 20 Oe and duration of a few $\mu$s. The jumps take place when
the total current in the wall, not the current density, exceeds some critical
value. In addition there are small jumps and/or smooth penetration, and their
contribution can reach 20% of the total penetrating flux. It is demonstrated
that the magnetic field inside the cylinder exhibits several oscillations. The
number of giant jumps reduces with temperature.


title:
Identifying Structures in Social Conversations in NSCLC Patients through
  the Semi-Automatic extraction of Topical Taxonomies

abstract:
  The exploration of social conversations for addressing patient's needs is an
important analytical task in which many scholarly publications are contributing
to fill the knowledge gap in this area. The main difficulty remains the
inability to turn such contributions into pragmatic processes the
pharmaceutical industry can leverage in order to generate insight from social
media data, which can be considered as one of the most challenging source of
information available today due to its sheer volume and noise. This study is
based on the work by Scott Spangler and Jeffrey Kreulen and applies it to
identify structure in social media through the extraction of a topical taxonomy
able to capture the latent knowledge in social conversations in health-related
sites. The mechanism for automatically identifying and generating a taxonomy
from social conversations is developed and pressured tested using public data
from media sites focused on the needs of cancer patients and their families.
Moreover, a novel method for generating the category's label and the
determination of an optimal number of categories is presented which extends
Scott and Jeffrey's research in a meaningful way. We assume the reader is
familiar with taxonomies, what they are and how they are used.